WO2022102551A1 - Balancing circuit and work machine - Google Patents

Abstract

Provided are: a balancing circuit in which a plurality of battery packs that are not mutually balanced can be simultaneously used, thus achieving improvement in workability; and a work machine. The balancing circuit includes: a first battery pack mounting section 2c and a second battery pack mounting section 2d in which a first battery pack 10 and a second battery pack 20 can be mounted, respectively; a parallel connection circuit that connects in parallel the first battery pack mounting section 2c and the second battery pack mounting section 2d; and suppression units M1, M2 that suppress a charging current flowing through the parallel connection circuit from one side to another side in a state where the first battery pack mounting section 2c and the second battery pack mounting section 2d each have a battery pack mounted therein.

Description

Balance circuit and working machine

The present invention relates to a balance circuit and a working machine to which a plurality of battery packs can be mounted.

In recent years, cordless type work machines using battery packs, for example, electric tools have become widespread, while cordless type work machines are also required to have high output like the corded type. Patent Document 1 below describes a power tool that achieves high output by connecting two battery packs in parallel.

Japanese Unexamined Patent Publication No. 2020-054169

The configuration of Patent Document 1 is such that the current does not flow from one of the two battery packs to the other, that is, the balance of the voltage (remaining capacity) cannot be adjusted between the two battery packs, so that the discharge path of the two battery packs is set. Two backflow prevention means are provided for each. Therefore, so-called balanced charging, in which a battery pack having a high voltage (remaining capacity) is charged to a battery pack having a low voltage (remaining capacity), cannot be performed. Therefore, the balance between the two battery packs cannot be adjusted, and the space between the two battery packs cannot be fully utilized.

Therefore, in order to solve the above problems, it is an object of the present invention to provide a balance circuit and a work machine in which a plurality of battery packs that are not balanced with each other can be used at the same time and workability is improved. Another object of the present invention is to provide a balance circuit and a working machine in which an inrush current does not easily flow when the potential difference between a plurality of battery packs is large. In addition, it has a balance circuit and a balance circuit that can adjust the balance of multiple battery packs while suppressing the charging current (inrush current) with a simple configuration, and use multiple battery packs in parallel. The purpose is to provide a working machine that can be used.

One aspect of the invention is a balanced circuit. This balance circuit includes a plurality of battery pack mounting portions having a first battery pack mounting portion and a second battery pack mounting portion to which the battery pack can be mounted, and the first battery pack mounting portion and the second battery pack mounting portion. The first battery pack is mounted in a state where the battery pack is mounted in the parallel connection circuit connected in parallel and the battery pack mounted in each of the first battery pack mounting portion and the second battery pack mounting portion provided in the parallel connection circuit. It is characterized by including a portion and a suppression portion that suppresses a charging current flowing through the parallel connection circuit from one side to the other side of the second battery pack mounting portion. According to this aspect, an unbalanced battery pack can be used and workability can be improved. In addition, the balance can be adjusted while suppressing the charging current between a plurality of battery packs with a simple configuration. Then, a plurality of balanced battery packs can be connected and used in parallel.

The suppression portion includes a first switching element provided in a first discharge path between the first battery pack mounting portion and the driving portion, and a second switching element between the second battery pack mounting portion and the driving portion. It may have a second switching element provided in the discharge path.

It is connected in parallel with the first switching element, and while passing a current in the direction from the first battery pack mounting portion to the second battery pack mounting portion, the first battery pack mounting portion is connected to the second battery pack mounting portion. The current in the direction toward the above is connected in parallel with the first diode that cuts off the second switching element, and the current is passed in the direction from the second battery pack mounting portion to the first battery pack mounting portion. It may have a second diode that cuts off the current in the direction from the first battery pack mounting portion to the second battery pack mounting portion.

When the voltage difference between the battery pack with the larger voltage and the battery pack with the smaller voltage mounted on the plurality of battery pack mounting portions is equal to or larger than the potential difference threshold value, the balance between the battery packs is not adjusted. May be good.

One aspect of the present invention is a working machine. This working machine includes the balance circuit, a control unit that controls the first switching element and the second switching element, and the driving unit that is driven by the electric power of the battery pack mounted on the battery pack mounting portion. When the control unit turns on the first switching element and the second switching element, the balance circuit is a battery pack mounted on each of the first battery pack mounting portion and the second battery pack mounting portion. The charging current is configured to flow from one side to the other side of the first battery pack mounting portion and the second battery pack mounting portion so that the potential difference becomes small. According to this aspect, an unbalanced battery pack can be used and workability can be improved. In addition, the balance can be adjusted while suppressing the charging current between a plurality of battery packs with a simple configuration. Then, a plurality of balanced battery packs can be connected and used in parallel.

One aspect of the present invention is a working machine. In this working machine, the potential difference between the balance circuit, the drive unit driven by the power of the battery pack mounted on the battery pack mounting portion, and the battery pack mounted on each of the plurality of battery pack mounting portions is small. The balance adjustment circuit that limits the discharge current from the battery pack with the higher voltage to the battery pack with the lower voltage and adjusts the balance between the battery packs is connected in parallel. It is characterized by including the parallel connection circuit connected to the drive unit. According to this aspect, an unbalanced battery pack can be used and workability can be improved. In addition, inrush current can be prevented.

The balance adjustment circuit may have a charging circuit for charging from the battery pack having the higher voltage to the battery pack having the lower voltage.

It may be configured to be switchable whether or not to charge via the charging circuit according to the potential difference.

When the potential difference is equal to or greater than a predetermined value, a first balance circuit configured to charge the battery pack having a higher voltage to the battery pack having a lower voltage may be provided via the charging circuit.

The first balance circuit is the first switching element or the second switching element provided between the charging circuit, the battery pack mounting portion to which the battery pack having the higher voltage is connected, and the charging circuit. And may have.

When the potential difference is less than a predetermined value, it may have a second balance circuit configured to charge the battery pack having a larger voltage to the battery pack having a smaller voltage without going through the charging circuit. ..

The second balance circuit may include the first switching element and the second switching element.

A control unit for controlling the on / off of the suppression unit or the first switching element and the second switching element is provided, and the control unit charges the battery pack having a higher voltage to the battery pack having a lower voltage. In this state, the first balance circuit may be configured to switch to the second balance circuit.

The suppression unit or the control unit for controlling the on / off of the first switching element and the second switching element is provided, and the control unit is the balance adjustment circuit so that a current of a predetermined value or more does not flow in the parallel connection circuit. May be configured to control. According to this, it is possible to adjust the balance while suppressing the flow of a large current.

The balance adjustment circuit may be provided in a discharge path between each of the plurality of battery pack mounting portions and the driving portion, and may include a blocking portion that cuts off the path between the plurality of battery pack mounting portions.

The balance adjustment circuit may include a discharge circuit having a resistance portion for discharging the battery pack having the larger voltage when the battery packs mounted on the plurality of battery pack mounting portions have a potential difference. According to this, the charging circuit is unnecessary and the circuit becomes simple.

A control unit for controlling on and off of the first switching element and the second switching element is provided, and the control unit controls the PWM duty ratio of at least one of the first switching element and the second switching element. It is also good. It was

A display unit that displays the status of each battery pack mounted on the plurality of battery pack mounting portions may be provided.

The display unit may have a remaining amount display unit that displays the remaining amount of the battery pack.

The display unit may include a balance display unit that indicates that the battery pack is being balanced.

The display unit may have an operation prohibition display unit that indicates that the balance is not adjusted. According to these display units, the operator can grasp the state of the battery pack.

It should be noted that any combination of the above components and a conversion of the expression of the present invention between methods, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a balanced circuit and a working machine in which a plurality of battery packs that are not balanced with each other can be used at the same time and workability is improved. Further, it is possible to provide a balance circuit and a working machine in which an inrush current is difficult to flow when the potential difference between a plurality of battery packs is large. Further, it is possible to provide a balance circuit and a working machine capable of adjusting the balance while suppressing the charging current between the battery packs with a simple configuration.

The perspective view of the working machine 1 which concerns on Embodiment 1 of this invention. The external view of the control panel 40 of the work machine 1. A simple circuit configuration diagram of the work machine 1. Detailed circuit configuration diagram of the first part of the working machine 1. Detailed circuit configuration diagram of the second part of the work machine 1. FIG. 3 is a circuit diagram showing a specific example of the charging circuit 16 shown in FIGS. 3 and 4. In charging (balance adjustment) from the first battery pack 10 to the second battery pack 20 of the working machine 1, the voltage v ₁ of the first battery pack 10, the voltage v ₂ of the second battery pack 20, and the charging current i _out . A graph showing changes over time. The flowchart which shows the first half of the control of the work machine 1. The flowchart which shows the latter half of the control of the work machine 1. A time chart showing the operation of the work machine 1. The simple circuit block diagram of the working machine 1A which concerns on Embodiment 2 of this invention. The graph which shows the time change of the voltage v ₁ of the 1st battery pack 10, the voltage v ₂ of the 2nd battery pack 20, and the current consumption i _out in the balance adjustment by the discharge of the 1st battery pack 10 of the working machine 1A. The control flowchart of the working machine 1A. A time chart showing the operation of the working machine 1A. The simple circuit block diagram of the working machine 1B which concerns on Embodiment 3 of this invention. Detailed circuit block diagram of the first part of the working machine 1B. In charging (balance adjustment) from the first battery pack 10 to the second battery pack 20 of the working machine 1B, the voltage v ₁ of the first battery pack 10, the voltage v ₂ of the second battery pack 20, and the charging current i _out . A graph showing changes over time. The control flowchart of the working machine 1B. A time chart showing the operation of the work machine 1B.

In the following, the same or equivalent components, members, etc. shown in the drawings are designated by the same reference numerals, and duplicate description thereof will be omitted as appropriate. The embodiment is not limited to the invention but is an example. Not all features and combinations thereof described in embodiments are essential to the invention.

(Embodiment 1) The first embodiment of the present invention will be described with reference to FIGS. 1 to 10. The present embodiment relates to the working machine 1. The working machine 1 is a power tool. FIG. 1 defines the front-back, up-down, and left-right directions of the working machine 1 that are orthogonal to each other. The working machine 1 is powered by the detachable first battery pack 10 and the second battery pack 20.

The working machine 1 includes a housing 2 constituting an outer frame. The housing 2 has a body portion 2a, a handle portion 2b, a first battery pack mounting portion 2c, and a second battery pack mounting portion 2d. The body portion 2a is a substantially cylindrical tubular portion whose central axis is parallel to the front-rear direction. The handle portion 2b extends downward from the intermediate portion in the front-rear direction of the body portion 2a. The first battery pack mounting portion 2c is provided on the lower left portion of the handle portion 2b. The second battery pack mounting portion 2d is provided on the lower right portion of the handle portion 2b. In the working machine 1, the portion excluding the first battery pack 10 and the second battery pack 20 corresponds to the working machine main body.

At the front end portion of the body portion 2a, a tip tool mounting portion 9 to which a tip tool (not shown) can be mounted is provided. The body portion 2a accommodates a drive mechanism for rotationally driving the tip tool. The drive mechanism includes a motor (drive unit) 33 shown in FIG. 3 and a rotation transmission mechanism (not shown). A trigger switch 7 is provided at the upper end of the handle portion 2b. The first battery pack mounting portion 2c mounts the first battery pack 10 in a detachable manner. The second battery pack mounting portion 2d mounts the second battery pack 20 in a detachable manner. The first battery pack 10 and the second battery pack 20 are of the same type and have the same rated voltage and rated capacity.

The control panel 40 shown in FIG. 2 is provided on, for example, the upper surface of the first battery pack mounting portion 2c or the second battery pack mounting portion 2d. The control panel 40 has an operation mode button 41, an operation mode confirmation LED 42, a light mode button 43, a light mode confirmation LED 44, a battery remaining amount display unit 45, a battery remaining amount confirmation button 46, an operation prohibition display LED 47, and a battery balance display. LED48 is provided. The lighting of each LED of the control panel 40 is controlled by the main body control unit 30 (FIG. 3).

The operation mode button 41 is a button for switching the operation mode of the work machine 1. The operation mode confirmation LED 42 is an operation mode display unit for displaying the current operation mode. The light mode button 43 is a button for switching the lighting mode of a light (not shown). The light mode confirmation LED 44 is a light mode display unit for displaying the lighting mode of the current light.

The battery remaining amount display unit 45 is a display unit for displaying the remaining amount of each of the first battery pack 10 and the second battery pack 20. In the illustrated example, the battery level indicator 45 has four LEDs for each of the first battery pack 10 and the second battery pack 20. The battery remaining amount confirmation button 46 is a button to be pressed when confirming the remaining amount display by the battery remaining amount display unit 45. When the battery remaining amount confirmation button 46 is pressed, the remaining battery level display unit 45 displays the remaining amount for a certain period of time.

The operation prohibition display LED 47 is the light emitting diode D10 of FIG. 5, and is an operation prohibition display unit that lights up when the work machine 1 cannot operate due to a large potential difference between the first battery pack 10 and the second battery pack 20. The battery balance in-display LED 48 is the light emitting diode D7 of FIG. 5, and is a balance display unit that lights up when the balance adjustment of the first battery pack 10 and the second battery pack 20 is being performed, which will be described later.

FIG. 3 is a simplified circuit configuration diagram of the working machine 1. In the first battery pack 10 and the first battery pack mounting portion 2c, positive terminals, negative terminals, LD terminals, and LS terminals are connected to each other. Similarly, in the second battery pack 20 and the second battery pack mounting portion 2d, the positive terminals, the negative terminals, the LD terminals, and the LS terminals are connected to each other.

The first battery pack 10 has a first battery cell set 11 and a first battery control unit 12. The second battery pack 20 has a second battery cell set 21 and a second battery control unit 22. The first battery cell set 11 and the second battery cell set 21 are each in which a plurality of secondary battery cells are connected in series. The first battery control unit 12 and the second battery control unit 22 include, for example, an MCU (MicroControllerUnit).

When the first battery control unit 12 detects an abnormality in the first battery cell set 11, it outputs an abnormality detection signal to the LD terminal. Abnormalities include over-discharging of battery cells and high temperatures. The first battery control unit 12 outputs a signal indicating the battery temperature and the charging state of the first battery cell set 11 to the LS terminal. When the second battery control unit 22 detects an abnormality in the second battery cell set 21, it outputs an abnormality detection signal to the LD terminal. The second battery control unit 22 outputs a signal indicating the battery temperature and the charging state of the second battery cell set 21 to the LS terminal.

The switching element M1 as the first blocking unit and the switching element M2 as the second blocking unit are N-channel MOSFETs, respectively. The source of the switching element M1 is connected to the positive terminal of the first battery pack mounting portion 2c. The switching element M1 is provided in the first discharge path connecting the first battery pack mounting portion 2c and the motor 33. The source of the switching element M2 is connected to the positive terminal of the second battery pack mounting portion 2d. The switching element M2 is provided in the second path path connecting the second battery pack mounting portion 2d and the motor 33. The drain of the switching element M1 and the drain of the switching element M2 are connected to each other. The on / off of the switching element M1 and the switching element M2, that is, the gate voltage is controlled by the main body control unit 30. The switching element M1 corresponds to the first switching element of the present invention, the switching element M2 corresponds to the second switching element of the present invention, and the switching elements M1 and M2 correspond to the suppression unit of the present invention.

The switching element M1 has a parasitic diode (body diode) D1 between the source and the drain. The parasitic diode D1 passes the current from the source to the drain of the switching element M1 regardless of whether the switching element M1 is turned on or off, while blocking the current from the drain to the source. That is, the current in the direction of the motor 33 is passed from the first battery pack mounting portion 2c, while the current in the opposite direction is cut off. The switching element M2 has a parasitic diode D2 between the source and the drain. The parasitic diode D2 passes the current from the source to the drain of the switching element M2 regardless of whether the switching element M2 is turned on or off, while blocking the current from the drain to the source. That is, the current in the direction of the motor 33 is passed from the second battery pack mounting portion 2d, while the current in the opposite direction is cut off. The parasitic diode D1 corresponds to the first diode of the present invention, and the parasitic diode D2 corresponds to the second diode of the present invention.

The drain of the switching element M1 and the drain of the switching element M2 are connected to the charging input terminal of the charging circuit 16. The charging circuit 16 is a part of the balance adjustment circuit, and the current higher voltage of the first battery pack 10 and the second battery pack 20 (hereinafter referred to as “high voltage battery pack”) to the lower one (hereinafter referred to as “low”). This is a circuit for passing a charging current through a voltage battery pack ()) so that the potential difference between the first battery pack 10 and the second battery pack 20 becomes smaller. The charge output terminal of the charging circuit 16 is connected to the anodes of the diodes D8 and D9. The cathode of the diode D8 is connected to the positive terminal of the second battery pack mounting portion 2d. The cathode of the diode D9 is connected to the positive terminal of the first battery pack mounting portion 2c. The operation of the charging circuit 16 is controlled by a charging control signal from the main body control unit 30. The charging circuit 16 is provided in a path different from the first discharge path and the second discharge path.

The drain of the switching element M1 and the drain of the switching element M2 are connected to the source of the switching element M5. The switching element M5 is a P-channel MOSFET. The drain of the switching element M5 is connected to the input terminal of the power supply circuit 18. The on / off of the switching element M5, that is, the gate voltage is controlled by the on / off of the trigger switch 7 and the power on / off signal from the main body control unit 30.

The power supply circuit 18 generates a power supply voltage of the main body control unit 30 and supplies it to the main body control unit 30. The inverter drive circuit 31 includes, for example, a half-bridge circuit of a gate driver, and controls on / off of the switching elements Q1 to Q6, that is, the gate voltage by the control of the main body control unit 30. The switching elements Q1 to Q6 are N-channel MOSFETs. The switching elements Q1 to Q6 are connected by a three-phase bridge to form an inverter circuit. The notification LED circuit 32 controls the lighting of the operation prohibition display LED 47 and the battery balance in progress display LED 48 of FIG. 2 under the control of the main body control unit 30.

The drain of the switching element M1 and the drain of the switching element M2 are connected to the drains of the switching elements Q1 to Q3. The sources of the switching elements Q1 to Q3 are connected to the drains of the motor 33 and the switching Q4 to Q6. The sources of switching Q4 to Q6 are connected to the negative terminal of the first battery pack mounting portion 2c via the resistor R12, and are connected to the negative terminal of the second battery pack mounting portion 2d via the resistor R3.

The switching elements M1 and M2 form a parallel connection circuit in which the first battery pack 10 and the second battery pack 20 are connected in parallel and connected to the motor 33. The parallel connection circuit includes a circuit connecting the first battery pack mounting portion 2c, the switching element M1, the switching element M2, and the battery pack mounting portion 2d. When the voltage of the first battery pack 10 is higher than the voltage of the second battery pack 20, the switching element M1 and the charging circuit 16 form the first balance circuit. When the voltage of the second battery pack 20 is higher than the voltage of the first battery pack 10, the switching element M2 and the charging circuit 16 form the first balance circuit. The switching elements M1 and M2 have a low voltage from the high voltage battery pack without going through the charging circuit 16 when the potential difference between the first battery pack 10 and the second battery pack 20 is equal to or less than a predetermined value (second potential difference threshold) described later. A second balance circuit for charging the battery pack is configured.

4 and 5 are detailed circuit configuration diagrams of the working machine 1. 4 and 5 show in detail the circuit configurations of the parts other than the first battery pack 10 and the second battery pack 20 as compared with FIG.

The first voltage detection circuit 13 is a circuit for transmitting the output voltage (V1_DET) of the first battery pack 10 to the main body control unit 30. The first voltage detection circuit 13 includes switching elements M11 and M12, and resistors R8 and R9. The switching element M11 is an N-channel MOSFET, and the switching element M12 is a P-channel MOSFET.

The source of the switching element M11 is connected to the positive terminal of the first battery pack 10. One end of the resistor R8 is connected to the source of the switching element M11, and the other end is connected to the gate of the switching element M11 and one end of the resistor R9. The other end of the resistor R9 is connected to the drain of the switching element M12. The source of the switching element M12 is connected to the ground and is connected to the negative terminal of the first battery pack 10 via the resistor R12. The on / off of the switching element M12, that is, the gate voltage (V1_DET_SIG) is controlled by the main body control unit 30.

When the switching element M12 is turned on by the main body control unit 30, current flows in the order of the positive terminal of the first battery pack 10, the resistors R8, R9, the switching element M12, the resistor R12, and the negative terminal of the first battery pack 10, and the resistance. Due to the voltage drop in R8, the gate-source voltage of the switching element M11 becomes negative, and the switching element M11 turns on. As a result, the output voltage (V1_DET) of the first battery pack 10 is input to the main body control unit 30.

The second voltage detection circuit 23 is a circuit for transmitting the output voltage (V2_DET) of the second battery pack 20 to the main body control unit 30, and is configured in the same manner as the first voltage detection circuit 13 and operates in the same manner. That is, when the switching element M14 is turned on by the main body control unit 30 (V2_DET_SIG), the positive terminal of the second battery pack 20, the resistors R10, R11, the switching element M14, the resistor R3, and the negative terminal of the second battery pack 20 are in this order. A current flows, the voltage drop in the resistor R10 causes the gate-source voltage of the switching element M13 to become negative, and the switching element M13 turns on. As a result, the output voltage (V2_DET) of the second battery pack 20 is input to the main body control unit 30.

The first battery on circuit 14 is a circuit for turning on the switching element M1. The first battery-on circuit 14 includes switching elements M9 and M10, and resistors R6 and R7. The switching element M9 is an N-channel MOSFET, and the switching element M10 is a P-channel MOSFET.

The source of the switching element M10 is connected to the output terminal of the battery-side gate voltage circuit 18a. One end of the resistor R6 is connected to the source of the switching element M10, and the other end is connected to the gate of the switching element M10 and one end of the resistor R7. The other end of the resistor R7 is connected to the drain of the switching element M9. The source of the switching element M9 is connected to the ground and is connected to the negative terminal of the first battery pack 10 via the resistor R12. The on / off of the switching element M9, that is, the gate voltage (VG_BAT_SIG1) is controlled by the main body control unit 30.

When the switching element M9 is turned on by the main body control unit 30, current flows in the order of the output terminal of the battery side gate voltage circuit 18a, the resistors R6, R7, the switching element M9, the resistor R12, and the negative terminal of the first battery pack 10. Due to the voltage drop in the resistor R6, the gate-source voltage of the switching element M10 becomes negative, and the switching element M10 turns on. As a result, the voltage (VG_BAT) of the output terminal of the gate voltage circuit 18a for the battery side is input to the gate of the switching element M1, and the switching element M1 is turned on.

The second battery on circuit 24 is a circuit for turning on the switching element M2, and is configured in the same manner as the first battery on circuit 14 and operates in the same manner. That is, when the switching element M6 is turned on by the main body control unit 30, the current is in the order of the output terminal of the battery side gate voltage circuit 18a, the resistors R4, R5, the switching element M6, the resistor R3, and the negative terminal of the second battery pack 20. The voltage drop in the resistor R4 causes the gate-source voltage of the switching element M8 to become negative, and the switching element M8 turns on. As a result, the voltage (VG_BAT) of the output terminal of the gate voltage circuit 18a for the battery side is input to the gate of the switching element M2, and the switching element M2 is turned on.

The abnormality detection circuit 15 includes diodes D3 and D4. The anodes of the diodes D3 and D4 are connected to the abnormality detection signal input terminal of the main body control unit 30. The cathode of the diode D3 is connected to the LD terminal of the first battery pack 10. The cathode of the diode D4 is connected to the LD terminal of the second battery pack 20. The abnormality detection circuit 15 outputs a low-level LD signal (LD) indicating an abnormality when at least one of the LD signals (LD1, LD2) from the first battery pack 10 and the second battery pack 20 reaches a low level indicating an abnormality. It is transmitted to the main body control unit 30.

The power supply circuit 18 includes a battery-side gate voltage circuit 18a, a motor drive gate voltage circuit 18b, and a control power supply circuit 18c. The battery-side gate voltage circuit 18a boosts the output voltage of the first battery pack 10 and the second battery pack 20 into a voltage (VG_BAT) for inputting to the gates of the switching elements M1 and M2, for example, a battery voltage + 15V. It is a circuit. Since it is desirable that both or one of the switching elements M1 and M2 are always turned on during motor drive, charge control, and balance control, a circuit such as a charge pump is used. The motor drive gate voltage circuit 18b is a step-down circuit that converts the output voltages of the first battery pack 10 and the second battery pack 20 into a voltage for inputting to the gates of the switching elements Q1 to Q6, for example, 15V. It is a linear regulator circuit or the like. The control power supply circuit 18c is a step-down circuit that converts the output voltage of the motor drive gate voltage circuit 18b into the power supply voltage of the main body control unit 30, the notification LED circuit 32, and other electronic components 34, for example, 5V. It is a linear regulator circuit or the like.

The power-on circuit 17 inputs the output voltages of the first battery pack 10 and the second battery pack 20 to the battery-side gate voltage circuit 18a and the motor drive gate voltage circuit 18b in response to the on operation of the trigger switch 7. The gate voltage circuit 18a for the battery side and the motor drive from the first battery pack 10 and the second battery pack 20 for a certain period of time even after the trigger switch 7 is turned off by the power on signal (MCU_PWON) from the main body control unit 30. It is a circuit that maintains the voltage input to the gate voltage circuit 18b.

The power-on circuit 17 includes switching elements M5 and M7, resistors R1 and R2, and a trigger switch 7. As described above, the switching element M5 is a P-channel MOSFET, and the switching element M7 is an N-channel MOSFET. The source of the switching element M5 is connected to the drains of the switching elements M1 and M2 as described above. One end of the resistor R1 is connected to the source of the switching element M5, and the other end is connected to the gate of the switching element M5 and one end of the resistor R2. The other end of the resistor R2 is connected to one end of the trigger switch 7 and the drain of the switching element M7. The other end of the trigger switch 7 and the source of the switching element M7 are connected to the ground. The on / off of the switching element M7, that is, the gate voltage is controlled by the power on signal (MCU_PWON) from the main body control unit 30. The on / off of the trigger switch 7 is switched by the operation of the operator.

When the trigger switch 7 is turned on, the positive terminal of the first battery pack 10 (and the positive terminal of the second battery pack 20), the switching element M1 (and the switching M2), the resistors R1, R2, the trigger switch 7, and the ground are used. Current flows in order, the voltage drop between the resistors R1 causes the gate-source voltage of the switching element M5 to become negative, and the switching element M5 turns on. As a result, the output voltages of the first battery pack 10 and the second battery pack 20 are input to the battery side gate voltage circuit 18a and the motor drive gate voltage circuit 18b.

The notification LED circuit 32 includes a light emitting diode D7 (battery balance in-display LED48), a light emitting diode D10 (operation prohibition display LED47), resistors R14 and R15, and switching elements M22 and M23. The switching elements M22 and M23 are N-channel MOSFETs.

The anodes of the light emitting diodes D7 and D10 are connected to the output terminals of the control power supply circuit 18c. The cathode of the light emitting diode D7 is connected to one end of the resistor R14. The other end of the resistor R14 is connected to the drain of the switching element M22. The cathode of the light emitting diode D10 is connected to one end of the resistor R15. The other end of the resistor R15 is connected to the drain of the switching element M23. The sources of the switching elements M22 and M23 are connected to the ground. The on / off of the switching elements M22 and M23, that is, the gate voltage (BALANCE_LED_SIG, PROHIBIT_LED_SIG) is controlled by the main body control unit 30.

When the switching element M22 is turned on by the main body control unit 30 (BALANCE_LED_SIG), current flows in the order of the output terminal of the control power supply circuit 18c, the light emitting diode D7, the resistor R14, the switching element M22, and the ground, and the light emitting diode D7 lights up. When the switching element M23 is turned on by the main body control unit 30 (PROHIBIT_LED_SIG), current flows in the order of the output terminal of the control power supply circuit 18c, the light emitting diode D10, the resistor R15, the switching element M23, and the ground, and the light emitting diode D10 lights up.

The main body control unit 30 includes an MCU 30a. The main body control unit 30 detects the output current (I1) of the first battery pack 10 by the voltage across the resistor R12, and detects the output current (I2) of the second battery pack 20 by the voltage across the resistor R3. The main body control unit 30 detects the output voltage, temperature, and abnormality (LS1, LS2, etc.) of the first battery pack 10 and the second battery pack 20.

The main body control unit 30 controls the on / off of the switching element M1 through the on / off of the switching element M9, and controls the on / off of the switching element M2 through the on / off of the switching element M6. The main body control unit 30 switches between conduction and disconnection of the input voltage to the power supply circuit 18 through on / off of the switching element M7. The main body control unit 30 outputs a charging signal (CHARGE_SIG) to the charging circuit 16 and controls the charging circuit 16. The main body control unit 30 controls the lighting of the light emitting diode D7 by turning on / off the switching element M22, and controls the lighting of the light emitting diode D10 by turning on / off the switching element M23. The main body control unit 30 controls the on / off of the switching elements Q1 to Q6 (based on INV_SIG1 to 6) through the control of the inverter drive circuit 31, and controls the drive of the motor 33.

FIG. 6 is a circuit diagram showing a specific example of the charging circuit 16 shown in FIGS. 3 and 4. This circuit is a non-isolated step-down DC / DC converter. The switching element SW such as the FET is switched and controlled by the charging signal (CHARGE_SIG) applied from the main body control unit 30.

FIG. 7 shows the voltage v ₁ of the first battery pack 10, the voltage v ₂ of the second battery pack 20, and the charging in charging (balance adjustment) from the first battery pack 10 to the second battery pack 20 of the working machine 1. It is a graph which shows the time change of a current i _out . This graph is an example of a case where the voltage of the first battery pack 10 is higher than that of the second battery pack 20 and the potential difference is larger than a predetermined value.

At time t0, the main body control unit 30 starts the balance adjustment control. Specifically, the main body control unit 30 turns on the switching element M1 and turns off the switching element M2 at time t0, so that the charging circuit 16 has a constant current output, that is, the first battery pack mounting unit 2c and It is controlled so that a current exceeding the constant current does not flow between the second battery pack mounting portions 2d (to limit the discharge current of the high voltage battery pack). By this constant current charging, the charging current i _out is kept constant, the voltage v ₁ of the first battery pack 10 decreases linearly, and the voltage v ₂ of the second battery pack 20 increases linearly.

The main body control unit 30 switches the charging circuit 16 at time t1 when the potential difference between the first battery pack 10 and the second battery pack 20 drops below a predetermined value and constant current output from the charging circuit 16 becomes impossible. Switch to full ON charging that turns on the SW continuously. In full-on charging, the charging current i _out decreases as the potential difference between the first battery pack 10 and the second battery pack 20 decreases.

The main body control unit 30 stops the charging circuit 16 (turns off the switching element SW) and turns on the switching element M2 at the time t2 when the charging current i _out drops below the first current threshold value. As a result, the first battery pack 10 and the second battery pack 20 are short-circuited, and a charging current flows directly from the first battery pack 10 to the second battery pack 20 (short-circuit charging is started). Even in short-circuit charging, the charging current i _out decreases as the potential difference between the first battery pack 10 and the second battery pack 20 decreases.

When the potential difference between the first battery pack 10 and the second battery pack 20 becomes substantially zero at time t3, charging (balance adjustment) from the first battery pack 10 to the second battery pack 20 is completed. After that, the main body control unit 30 keeps turning on the switching elements M1 and M2.

8 and 9 show a control flow of the working machine 1. By turning on the trigger switch 7 (S1), the power supply circuit 18 is activated (S2), and the main body control unit 30 is activated (S3). The main body control unit 30 keeps the switching element M7 in the on state by the power-on signal, so that the power supply circuit 18 is kept in the active state even if the trigger switch 7 is turned off.

The main body control unit 30 is in a motor drive disallowed state (S4), and the operation prohibition display LED 47 is turned on (S5). The main body control unit 30 starts periodic measurement of the output voltage of the first battery pack 10 and the second battery pack 20 (S6), and periodically measures the output currents of the first battery pack 10 and the second battery pack 20. Measurement is started (S7).

When the potential difference between the first battery pack 10 and the second battery pack 20 is less than the first potential difference threshold (Yes in S8), the main body control unit 30 determines that the potential difference is the second potential difference threshold (second potential difference threshold <first potential difference). When it is larger than the threshold value (Yes of S9), the battery balance in-display LED 48 is turned on (S10), and the balance is adjusted to charge the low voltage battery pack from the high voltage battery pack with a constant current by controlling the charging circuit 16. (S11).

When the potential difference between the first battery pack 10 and the second battery pack 20 decreases and charging at a constant current becomes impossible (Yes in S12), the main body control unit 30 displays the battery balance in-display LED 48 in the first blinking pattern. Blinking is controlled (S13), and the balance is adjusted by full ON charging that continuously turns on the switching SW of the charging circuit 16 (S14).

When the charging current i _out by the charging circuit 16 becomes less than the first current threshold (Yes in S15), the main body control unit 30 controls the battery balance in-display LED 48 to blink in the second blinking pattern (S16), and the first battery pack. Balance adjustment is performed by short-circuit charging that short-circuits between 10 and the second battery pack 20 (S17). The blinking speed of the second blinking pattern is different from that of the first blinking pattern. The second blinking pattern may have a faster blinking speed than the first blinking pattern. The blinking speed may be increased as the balance adjustment approaches completion (closer to voltage equilibrium).

When the charging current due to short-circuit charging becomes less than the second current threshold value (Yes in S18), the main body control unit 30 turns off the battery balance in-display LED 48 (S19), enters the motor drive permission state (S20), and activates the operation prohibition display LED 47. Is turned off (S20a).

The main body control unit 30 drives the motor 33 when the trigger switch 7 is ON (ON of S21) (S22), and stops the motor 33 when the trigger switch 7 is OFF (OFF of S21) (S23). The main body control unit 30 may be in the motor drive permission state at the time of S17, and the operation prohibition display LED 47 may be turned off.

When the potential difference between the first battery pack 10 and the second battery pack 20 is equal to or less than the second potential difference threshold value in S9 (No in S9), the main body control unit 30 proceeds to S16. When the potential difference between the first battery pack 10 and the second battery pack 20 is equal to or greater than the first potential difference threshold value (No in S8) in S8, the main body control unit 30 blinks the operation prohibition display LED 47 for a certain period of time (S24), and then blinks the operation prohibition display LED 47 for a certain period of time (S24). The switching element M7 is turned off to cut off the input voltage to the power supply circuit 18 and stop (S25).

The first potential difference threshold is, for example, 10V when the rated voltage of the first battery pack 10 and the second battery pack 20 is 36V. For example, when one voltage is 38V and the other voltage is 28V, the voltage proceeds to No in S8. The second potential difference threshold is a potential difference at which a large current does not flow even when both the switching elements M1 and M2 are turned on, and is, for example, 0.05 V. The first current threshold value and the second current threshold value are, for example, 0.1 A.

FIG. 10 is a time chart showing the operation of the working machine 1. This time chart is for the case where the voltage of the first battery pack 10 is higher than the voltage of the second battery pack 20. When the voltage of the first battery pack 10 is lower than the voltage of the second battery pack 20, the time chart is obtained by switching the on / off of the switching elements M1 and M2 of FIG.

When the trigger switch 7 is turned on at time t11, the power supply circuit 18 is activated and the main body control unit 30 is activated. The main body control unit 30 sets the motor drive permission state to the prohibition state as the initial state, and sets the operation prohibition display LED signal to the high level. The main body control unit 30 turns on the switching element M1 at time t12, and starts charging control from the first battery pack 10 to the second battery pack 20 by the charging circuit 16. Although the trigger switch 7 is turned off at time t13, the power supply circuit 18 is maintained in the active state by the power on signal of the main body control unit 30, and the charging control by the charging circuit 16 is continued.

At time t14, the main body control unit 30 detects that the charging current i _out by the charging circuit 16 is less than the first current threshold, stops the charging circuit 16, turns on the switching element M2, and sets the first battery pack 10. And short-circuit charging that short-circuits between the second battery packs 20 is started. At time t15, the main body control unit 30 detects that the charging current due to short-circuit charging has become less than the second current threshold value, sets the motor drive permission state to the permission state, and switches the operation prohibition display LED signal from the high level to the low level. ..

When the trigger switch 7 is turned on at time t16, the main body control unit 30 drives the motor 33. When the trigger switch 7 is turned off at time t17, the main body control unit 30 stops the motor 33.

According to this embodiment, the following effects can be obtained.

(1) The high-voltage battery pack is charged to the low-voltage battery pack by the charging circuit 16 so that the potential difference between the first battery pack 10 and the second battery pack 20 becomes small, and then the first battery pack 10 and the second battery are charged. The packs 20 are short-circuited to charge the high-voltage battery pack to the low-voltage battery pack. Therefore, even if the balance between the first battery pack 10 and the second battery pack 20 is not balanced, the first battery pack 10 and the second battery pack 20 are placed in the first battery pack mounting portion 2c and the second battery pack mounting portion 2d. It can be used by connecting to, and workability can be improved. Further, it is possible to suppress the charging current (inrush current) from one battery pack to the other battery pack with a simple configuration.

(2) The charging circuit 16 first charges the high-voltage battery pack to the low-voltage battery pack with a constant current. Therefore, it is possible to suppress the flow of a charging current exceeding the constant current. Further, the charging circuit 16 switches to full ON charging in which the switching element SW of the charging circuit 16 is continuously turned on after constant current charging. Therefore, the potential difference between the first battery pack 10 and the second battery pack 20 can be made smaller than in the case where only constant current charging is completed.

(3) After full ON charging by the charging circuit 16, the first battery pack 10 and the second battery pack 20 are short-circuited, and the high-voltage battery pack is charged to the low-voltage battery pack by short-circuit charging. Therefore, the potential difference between the first battery pack 10 and the second battery pack 20 can be made smaller than in the case where only charging by the charging circuit 16 is completed.

(4) Since the current path between the positive terminal of the first battery pack 10 and the positive terminal of the second battery pack 20 can be cut off by the switching elements M1 and M2, the first battery pack 10 and the second battery pack 20 Even if there is a potential difference of, it is possible to prevent the inrush current from the high voltage battery pack to the low voltage battery pack.

(5) The switching element M1 cuts off only the current flowing into the positive terminal of the first battery pack 10, and the switching element M2 cuts off only the current flowing into the positive terminal of the second battery pack 20. Since the current in the reverse direction can flow through the parasitic diodes D1 and D2, even if the switching elements M1 and M2 are off, the high voltage battery pack supplies power to the power supply circuit 18 and supplies power to the main body control unit 30. can. Further, the number of switching elements can be reduced as compared with the case where the switching elements are further provided so as to cut off the current in both directions. Further, since the motor 33 can be driven from the first battery pack 10 and the second battery pack 20 with the loss of only the N-channel MOSFET having a small on-resistance, the efficiency is high.

(6) If the potential difference between the 1st battery pack 10 and the 2nd battery pack 20 is too large, the operation prohibition display LED 47 is blinked to notify the operator without performing the balance adjustment, and the balance adjustment takes time. It is convenient because it is possible to avoid the situation where the remaining capacity is too small after the balance adjustment.

(7) Since the lighting mode of the battery balance in-display LED 48 is changed according to the progress of the balance adjustment, the operator not only is in the balance adjustment by the battery balance in-display LED 48, but also the progress of the balance adjustment. It is also convenient to know.

(Embodiment 2) The second embodiment of the present invention will be described with reference to FIGS. 11 to 14. The present embodiment relates to the working machine 1A. Hereinafter, the differences from the first embodiment will be mainly described. The circuit of FIG. 11 differs from the circuit of FIG. 3 in that the charging circuit 16 and the diodes D8 and D9 are replaced with a discharge circuit (balance adjustment circuit) including the resistor R18 and the switching element M17, and the other parts are different. Match at the point. The switching element M17 is an N-channel MOSFET. The resistor R18 has a function of limiting the discharge current of the high voltage battery pack.

One end of the resistor R18 as a resistance portion is connected to the drain of the switching element M1 and the drain of the switching element M2. The other end of the resistor R18 is connected to the drain of the switching element M17. The source of the switching element M17 is connected to the negative terminal of the first battery pack mounting portion 2c via the resistor R12, and is connected to the negative terminal of the second battery pack mounting portion 2d via the resistor R3. The on / off of the switching element M17 is switched by a voltage balanced discharge signal input from the main body control unit 30 to the gate of the switching element M17.

FIG. 12 shows time changes of the voltage v ₁ of the first battery pack 10, the voltage v ₂ of the second battery pack 20, and the current consumption i _out in the balance adjustment by discharging the first battery pack 10 of the working machine 1A. It is a graph. This graph is an example when the voltage of the first battery pack 10 is higher than that of the second battery pack 20.

At time t20, the main body control unit 30 starts balance adjustment control. Specifically, at time t20, the main body control unit 30 turns on the switching element M1, turns off the switching element M2, turns on the switching element M17, and starts discharging from the first battery pack 10. The charging current i _out decreases as the voltage v ₁ of the first battery pack 10 decreases. The voltage v ₂ of the second battery pack 20 is constant and does not change. When the potential difference between the first battery pack 10 and the second battery pack 20 becomes equal to or less than the second potential difference threshold value at time t21, the main body control unit 30 turns off the switching element M17 and stops consumption by the resistor R18.

FIG. 13 is a control flowchart of the working machine 1A. Hereinafter, the differences from FIGS. 8 and 9 will be mainly described. After the same processing of S1 to S6 as in FIG. 8, the main body control unit 30 determines that the potential difference between the first battery pack 10 and the second battery pack 20 is less than the first potential difference threshold (Yes in S8). When it is larger than the second potential difference threshold (Yes in S9), the battery balance indicating LED 48 is turned on (S10), the switching element M17, and one of the switching elements M1 and M2 are turned on to discharge the high voltage battery pack (Yes). The balance is adjusted by the consumption of the resistor R18) (S11a).

When the potential difference between the first battery pack 10 and the second battery pack 20 becomes equal to or less than the second potential difference threshold in S9 (No in S9), the main body control unit 30 turns off the battery balance in-display LED 48 (S31), and the switching element M17. Is turned off to stop the consumption of the resistor R18 (S32), both the switching elements M1 and M2 are turned on (S33), the motor drive permission state is set (S34), and the operation prohibition display LED 47 is turned off (S34a). The main body control unit 30 drives the motor 33 when the trigger switch 7 is ON (ON of S35) (S36), and stops the motor 33 when the trigger switch 7 is OFF (OFF of S35) (S37).

FIG. 14 is a time chart showing the operation of the working machine 1A. This time chart is for the case where the voltage of the first battery pack 10 is higher than the voltage of the second battery pack 20. When the voltage of the first battery pack 10 is lower than the voltage of the second battery pack 20, the time chart is obtained by switching the on / off of the switching elements M1 and M2 of FIG.

When the trigger switch 7 is turned on at time t31, the power supply circuit 18 is activated and the main body control unit 30 is activated. The main body control unit 30 sets the motor drive permission state to the prohibition state as the initial state, and sets the operation prohibition display LED signal to the high level. The main body control unit 30 turns on the switching elements M1 and M7 at time t32, and starts the balance adjustment control of discharging from the first battery pack 10 to the resistor R18. Although the trigger switch 7 is turned off at time t33, the power supply circuit 18 is maintained in the active state by the power on signal of the main body control unit 30, and the balance adjustment control is continued.

At time t34, the main body control unit 30 detects that the potential difference between the first battery pack 10 and the second battery pack 20 is equal to or less than the second potential difference threshold value, turns off the switching element M7, and turns on the switching element M2. The motor drive permission state is set to the permission state, and the operation prohibition display LED signal is switched from the high level to the low level. When the trigger switch 7 is turned on at time t35, the main body control unit 30 drives the motor 33. When the trigger switch 7 is turned off at time t36, the main body control unit 30 stops the motor 33.

In the present embodiment, unlike the first embodiment, the balance is adjusted by consuming the electric power of the high voltage battery pack with the resistor R18, so that the circuit configuration is simplified.

(Embodiment 3) The third embodiment of the present invention will be described with reference to FIGS. 15 to 19. The present embodiment relates to the working machine 1B. The circuits of FIGS. 15 and 16 differ from the circuits of FIGS. 3 and 4 in that the charging circuit 16 and the diodes D8 and D9 are eliminated, and are otherwise consistent. In the present embodiment, the internal resistance of the first battery pack 10 and the second battery pack 20, and a slight inductor component and resistance component of the circuit pattern are utilized.

The switching elements M1 and M2 form a balance adjustment circuit. In the balance adjustment control, the main body control unit 30 sets the switching elements M1 and M2 connected to the positive terminal of the high voltage battery pack (hereinafter referred to as “high voltage side switching element”) to full ON (continuous ON) for switching. Among the elements M1 and M2, those connected to the positive terminal of the low voltage battery pack (hereinafter referred to as "low voltage side switching element") are controlled by PWM (Pulse Width Modulation). The main body control unit 30 controls the charging current by controlling the frequency and duty ratio of PWM control. By sufficiently increasing the frequency of the PWM control, it is possible to charge the low voltage battery pack from the high voltage battery pack while suppressing the charging current from becoming excessive (while limiting the discharge current of the high voltage battery pack).

FIG. 17 shows the voltage v ₁ of the first battery pack 10, the voltage v ₂ of the second battery pack 20, and the charging in charging (balance adjustment) from the first battery pack 10 to the second battery pack 20 of the working machine 1B. It is a graph which shows the time change of a current i _out . This graph is an example when the voltage of the first battery pack 10 is higher than that of the second battery pack 20.

The main body control unit 30 PWM-controls the switching element M2 while fully turning on the switching element M1 to charge the first battery pack 10 to the second battery pack 20. The effective value of the charging current i _out decreases as the potential difference between the first battery pack 10 and the second battery pack 20 decreases. As shown enlarged in FIG. 17, the charging current i _out flows intermittently. The main body control unit 30 may lower the frequency of the PWM control as the balance adjustment progresses (according to the decrease in the potential difference between the first battery pack 10 and the second battery pack 20). For example, the lower limit may be 100 kHz, the potential difference of 10 V may be 1 MHz, and the potential difference of 5 V may be 500 kHz. With such a configuration, even if the potential difference decreases, charging can be performed without lowering the effective current. Further, it may be changed linearly according to the voltage difference, or may be changed stepwise according to the range of the potential difference.

FIG. 18 is a control flowchart of the working machine 1B. Hereinafter, the differences from FIGS. 8 and 9 or 13 will be mainly described. After the same processing of S1 to S6 as in FIG. 8, the main body control unit 30 determines that the potential difference between the first battery pack 10 and the second battery pack 20 is less than the first potential difference threshold (Yes in S8). When it is larger than the second potential difference threshold (Yes in S9), the battery balance in-display LED 48 is turned on (S10), and the low voltage side switching element is PWM-controlled while the high voltage side switching element is fully turned on (continuously on). The balance is adjusted by control (S11b).

When the potential difference between the first battery pack 10 and the second battery pack 20 becomes equal to or less than the second potential difference threshold in S9 (No in S9), the main body control unit 30 turns off the battery balance in-display LED 48 (S31) to the low voltage side. The PWM control of the switching element is stopped (charge control is stopped) (S32a), both the switching elements M1 and M2 are turned on (S33), the motor drive permission state is set (S34), and the operation prohibition display LED 47 is turned off (S34a). .. The main body control unit 30 performs the processes of S35 to S37 in the same manner as in FIG.

FIG. 19 is a time chart showing the operation of the working machine 1B. This time chart is for the case where the voltage of the first battery pack 10 is higher than the voltage of the second battery pack 20. When the voltage of the first battery pack 10 is lower than the voltage of the second battery pack 20, the time chart is obtained by switching the on / off of the switching elements M1 and M2 of FIG.

When the trigger switch 7 is turned on at time t51, the power supply circuit 18 is activated and the main body control unit 30 is activated. The main body control unit 30 sets the motor drive permission state to the prohibition state as the initial state, and sets the operation prohibition display LED signal to the high level. The main body control unit 30 starts balance adjustment control for PWM control of the switching element M2 while fully turning on the switching element M1 (continuously ON) at time t52. Although the trigger switch 7 is turned off at time t53, the power supply circuit 18 is maintained in the active state by the power on signal of the main body control unit 30, and the balance adjustment control is continued.

At time t54, the main body control unit 30 detects that the potential difference between the first battery pack 10 and the second battery pack 20 is equal to or less than the second potential difference threshold value, switches the switching element M2 to full ON (continuous on), and motors the motor. The drive permission state is set to the permission state, and the operation prohibition display LED signal is switched from the high level to the low level. When the trigger switch 7 is turned on at time t55, the main body control unit 30 drives the motor 33. When the trigger switch 7 is turned off at time t56, the main body control unit 30 stops the motor 33.

In the present embodiment, unlike the first embodiment, the balance is adjusted by charging the low voltage battery pack from the high voltage battery pack without using the charging circuit 16, so that the circuit configuration is simplified. In the present embodiment, the output currents of the first battery pack 10 and the second battery pack 20 are periodically measured, and when an excessive current flows, the charge control is stopped or the PWM control frequency is increased. The function of suppressing the charging current may be added.

Although the present invention has been described above by taking the embodiment as an example, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, a modification example will be touched upon.

The working machines 1, 1A, and 1B may have three or more battery pack mounting portions, and may be capable of mounting three or more battery packs. Specific numerical values such as voltage, current, and threshold value shown in the embodiment are examples, and can be arbitrarily changed according to the design.

1 ... Working machine, 2 ... Housing, 2a ... Body part, 2b ... Handle part, 2c ... First battery pack mounting part, 2d ... Second battery pack mounting part, 7 ... Trigger switch, 9 ... Tip tool mounting part, 10 ... 1st battery pack, 11 ... 1st battery cell set, 12 ... 1st battery control unit, 13 ... 1st battery detection circuit, 14 ... 1st battery on circuit, 15 ... abnormality detection circuit, 16 ... charging circuit, 17 ... power-on circuit, 18 ... power supply circuit, 18a ... battery side gate voltage circuit, 18b ... motor drive gate voltage circuit, 18c ... control power supply circuit, 20 ... second battery pack, 21 ... second battery cell set, 22 ... 2nd battery control unit, 23 ... 2nd voltage detection circuit, 24 ... 2nd battery on circuit, 30 ... main body control unit, 31 ... inverter drive circuit, 32 ... notification LED circuit, 33 ... motor, 34 ... other electronic parts , 40 ... Control panel, 41 ... Operation mode button, 42 ... Operation mode confirmation LED, 43 ... Light mode button, 44 ... Light mode confirmation LED, 45 ... Battery level display, 46 ... Battery level confirmation button, 47 ... Operation prohibition display LED, 48 ... Battery balance in progress display LED
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Claims (15)

1. A plurality of battery pack mounting portions having a first battery pack mounting portion and a second battery pack mounting portion to which a battery pack can be mounted, and a plurality of battery pack mounting portions.
   A parallel connection circuit that connects the first battery pack mounting portion and the second battery pack mounting portion in parallel,
   The first battery pack mounting portion and the second battery pack mounting portion are provided in the parallel connection circuit, and the battery pack is mounted on each of the first battery pack mounting portion and the second battery pack mounting portion. A suppression unit that suppresses the charging current flowing through the parallel connection circuit from one side to the other,
   A balance circuit characterized by being equipped with.
2. The balance circuit according to claim 1.
   The suppression portion includes a first switching element provided in a first discharge path between the first battery pack mounting portion and the driving portion, and a second switching element between the second battery pack mounting portion and the driving portion. The second switching element provided in the discharge path and
   Have,
   A balance circuit characterized by that.
3. The balance circuit according to claim 2.
   It is connected in parallel with the first switching element, and while passing a current in the direction from the first battery pack mounting portion to the second battery pack mounting portion, the first battery pack mounting portion is connected to the second battery pack mounting portion. The first diode that cuts off the current in the direction toward
   It is connected in parallel with the second switching element, conducts current in the direction from the second battery pack mounting portion to the first battery pack mounting portion, and mounts the second battery pack from the first battery pack mounting portion. The second diode that cuts off the current in the direction toward the part,
   Have,
   A balance circuit characterized by that.
4. The balance circuit according to any one of claims 1 to 3.
   When the voltage difference between the battery pack with the larger voltage and the battery pack with the smaller voltage mounted on the plurality of battery pack mounting portions is equal to or larger than the potential difference threshold value, the balance between the battery packs is not adjusted. A characteristic balance circuit.
5. The balance circuit according to any one of claims 2 to 4,
   A control unit that controls the first switching element and the second switching element,
   The drive unit driven by the electric power of the battery pack mounted on the battery pack mounting unit,
   Equipped with
   When the control unit turns on the first switching element and the second switching element, the balance circuit has a potential difference between the battery packs mounted on the first battery pack mounting portion and the second battery pack mounting portion. A working machine characterized in that the charging current is configured to flow from one side to the other side of the first battery pack mounting portion and the second battery pack mounting portion so as to be smaller.
6. The balance circuit according to any one of claims 1 to 4,
   The drive unit driven by the electric power of the battery pack mounted on the battery pack mounting unit,
   The battery pack is limited in discharge current from the battery pack having a large voltage to the battery pack having a small voltage so that the potential difference between the battery packs mounted on each of the plurality of battery pack mounting portions is small. Equipped with a balance adjustment circuit that adjusts the balance between
   The parallel connection circuit is a working machine comprising connecting the battery packs in parallel and connecting them to the drive unit.
7. The working machine according to claim 6.
   The balance adjusting circuit is a working machine having a charging circuit for charging from a battery pack having a higher voltage to a battery pack having a lower voltage.
8. The working machine according to claim 7.
   A working machine characterized in that it can be switched whether or not to charge via the charging circuit according to the potential difference.
9. The working machine according to claim 8.
   When the potential difference is equal to or greater than a predetermined value, it has a first balance circuit configured to charge the battery pack having a higher voltage to the battery pack having a lower voltage via the charging circuit.
   The first balance circuit is the first switching element or the second switching element provided between the charging circuit, the battery pack mounting portion to which the battery pack having the higher voltage is connected, and the charging circuit. And, a working machine characterized by having.
10. The working machine according to claim 8 or 9.
    When the potential difference is less than a predetermined value, it has a second balance circuit configured to charge from the battery pack having a higher voltage to the battery pack having a lower voltage without going through the charging circuit.
    The second balance circuit is a working machine including the first switching element and the second switching element.
11. The working machine according to claim 10.
    A control unit for controlling the on / off of the suppression unit or the first switching element and the second switching element is provided.
    The control unit is characterized in that it is configured to switch from the first balance circuit to the second balance circuit while charging the battery pack having a lower voltage from the battery pack having a higher voltage. Working machine to do.
12. The working machine according to any one of claims 6 to 11.
    A control unit for controlling the on / off of the suppression unit or the first switching element and the second switching element is provided.
    The control unit is a working machine configured to control the balance adjustment circuit so that a current of a predetermined value or more does not flow in the parallel connection circuit.
13. The working machine according to claim 6.
    The balance adjusting circuit is characterized by including a discharge circuit having a resistance portion for discharging the battery pack having a larger voltage when the battery packs mounted on the plurality of battery pack mounting portions have a potential difference. Working machine.
14. The working machine according to claim 5.
    A control unit for controlling on / off of the first switching element and the second switching element is provided.
    The control unit is a working machine characterized in that it controls the PWM duty ratio of at least one of the first switching element and the second switching element.
15. The working machine according to any one of claims 4 to 14.
    A display unit for displaying the status of each battery pack mounted on the plurality of battery pack mounting portions is provided.
    The display unit is characterized by having at least one of a balance display unit that indicates that the battery pack is in the process of balance adjustment and an operation prohibition display unit that indicates that the balance adjustment is not performed. ..

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