WO2021084989A1

WO2021084989A1 - Battery pack and electrical device

Info

Publication number: WO2021084989A1
Application number: PCT/JP2020/036445
Authority: WO
Inventors: 聡史山口; 聡明増森; 浩之塙
Original assignee: 工機ホールディングス株式会社
Priority date: 2019-10-28
Filing date: 2020-09-25
Publication date: 2021-05-06
Also published as: JP7259983B2; JPWO2021084989A1

Abstract

Provided is a battery pack which can switch connection states of a plurality of cell units, wherein control is carried out such that the power consumption of two cell units is equal. A battery pack 100 has a first cell unit 146 and a second cell unit 147 each having a plurality of battery cells, and is configured so as to be able to switch between a parallel connection state and a series connection state in which the first and second cell units are connected in series to each other while the first cell unit is connected to a higher voltage side than the second cell unit, wherein a current consumption control means 195 that consumes power is provided on the first cell unit 146 side so that ON/OFF of the current consumption control means 195 can be controlled by a control signal 194 from a control unit 190. Due to this configuration, it is possible to maintain an equal power balance between the first and second cell units 146, 147.

Description

Battery pack and electrical equipment

The present invention relates to a battery pack and an electric device that operates a load such as a motor and lighting by using the battery pack.

As a power source for electric devices such as electric tools, a battery pack using a secondary battery such as a lithium ion battery is widely used. The battery pack is detachably attached to the main body of the electric device, and when the voltage drops due to discharge, the battery pack is removed from the main body of the electric device and charged using an external charging device. Normally, the output voltage of the battery pack is fixed, but in Patent Document 1, a plurality of cell units are provided in the housing accommodating the battery, and whether they are output as a series connection or a parallel connection is determined by the connection means. As selectable, a battery pack that can be used with devices of different voltages has been realized. By using this battery pack, it is not necessary to prepare different types of battery packs when using a plurality of electric devices. Further, the battery pack of Patent Document 1 does not require a special operation when switching the voltage, and there is no risk of an operation error occurring. Further, the battery pack of Patent Document 1 has a first cell unit and a second cell unit built-in, a microcomputer and a power supply are provided on one cell unit side, and a discharge circuit is provided on the other cell unit side. Is configured to operate in conjunction with the startup of the microcomputer.

Japanese Unexamined Patent Publication No. 2019-004631

In the battery pack of Patent Document 1, when the microcomputer is started, the discharge circuit is always operating regardless of the operating status (sleep mode, etc.) of the microcomputer, so that fine adjustment of the voltage balance is insufficient. Further, if a new power consumption circuit is added to the second cell unit side (the other cell unit side) in the battery pack of Patent Document 1, it may cause the voltage balance to be lost, and it is necessary to take measures against it. It was found by the verification of the inventors.

The present invention has been made in view of the above background, and an object of the present invention is a battery cell protection circuit provided for each of a plurality of cell units in a battery pack capable of switching the connection form of the plurality of cell units. It is an object of the present invention to provide a battery pack and electrical equipment in which a monitoring microcomputer (hereinafter referred to as "microcomputer") is provided and the imbalance of voltage balance between cell units can be adjusted by the microcomputer. Another object of the present invention is to finely adjust the power consumption on the other cell unit side by a microcomputer driven by the power on one cell unit side in a battery pack capable of switching the connection form of a plurality of cell units. Then, the present invention provides a battery pack in which the power consumption of both cell units is equalized, and an electric device using the battery pack.

The typical features of the invention disclosed in the present application will be described as follows. According to one feature of the present invention, a plurality of battery cells have at least first and second cell units as cell units connected in series, and the first cell unit is higher than the second cell unit. In the battery pack configured to switch between a series connection state in which the first and second cell units are connected in series with each other while connected to the voltage side and a connection state other than the series connection state, the first and first cells are used. Connected to one of the two cell units (for example, the second cell unit), the state of the battery cells constituting at least one cell unit can be monitored, and a discharge control signal for controlling the discharge of the battery pack can be output. A configured control unit (including a microcomputer) was provided. Further, an adjusting unit which is connected to the other of the first and second cell units (for example, the first cell unit) and finely adjusts the power consumption of the other cell unit side by the control signal from the control unit is provided. Further, the battery pack is connected to the control unit and includes a power supply unit that supplies a power supply voltage to the control unit, the power supply unit is connected to one cell unit, and the control unit is connected to the power supply unit and the negative electrode of one cell unit. , The power supply unit is configured to generate a power supply voltage from the voltage input from one of the cell units and supply it to the control unit.

According to another feature of the present invention, the power supply unit is connected to the second cell unit, and the power supply voltage is supplied from the second cell unit to the control unit via the power supply unit. Further, the control unit controls the adjustment unit according to its own state or the state of the connecting element connected to one of the cell units. Further, the adjusting unit is a discharge circuit including a resistance unit connected in parallel with the other cell unit and a switch unit connected in series with the resistance unit, and the control unit controls the switch unit.

According to still another feature of the present invention, the control unit includes at least a plurality of operation modes including a normal mode and a sleep mode, and in the normal mode, the control unit is the other cell unit than in the sleep mode. Control the adjustment unit so that the power consumption of the Further, a wireless communication mode is provided as an operation mode, and the control unit controls the adjustment unit so that the power consumption of the other cell unit is larger in the wireless communication mode than in the sleep mode. Here, when the voltage difference between the first and second cell units is equal to or greater than a predetermined value, the control unit always operates (on) the adjusting unit until the voltage difference becomes less than the predetermined value. When the voltage difference between the first and second cell units is less than a predetermined value, the control unit controls the adjustment unit according to the operation mode.

According to still another feature of the present invention, the electric device has a battery pack and at least the first electric device main body as an electric device main body that can be connected to the battery pack, and the battery pack is connected to the first electric device main body. If this is the case, the first and second cell units are connected in series with each other, and if the battery pack is not connected to the first electrical device body, the first and second cell units are connected to each other. It becomes electrically independent and disconnected. Further, the battery pack is in a parallel connection state in which the first and second cell units are connected in parallel to each other when the battery pack is connected to the second electric device main body, and the battery pack is in the second electric device main body. When removed from, the first and second cell units are configured to be electrically independent of each other in a disconnected state (the first and second cell units are electrically disconnected).

According to the present invention, since the adjusting unit for adjusting the power consumption of the other cell unit by the control signal from the control unit is provided, the balance of the power consumption between the plurality of cell units can be adjusted with high accuracy. Therefore, even if a load device (wireless communication circuit, indicator lamp, etc.) that consumes power is provided on one of the cell units, the balance of power consumption between the cell units can be finely adjusted according to the actual usage conditions. It will be possible. Further, since the operation or stop of the adjustment unit for adjusting the power consumption can be controlled by the control unit, the power balance between the cell units can be easily adjusted even if the microcomputer included in the control unit is put to sleep.

It is a figure for demonstrating the mounting state of the battery pack 100 which concerns on this invention to the power tool

main body

1, 51. It is a perspective view which shows the appearance of the battery pack 100 which concerns on embodiment of this invention. (A) is a partial perspective view showing the shapes of the positive electrode terminals (162 and 172) and the negative electrode terminals (167 and 177), and a diagram showing a connection circuit at the time of high voltage output, and (B) is a terminal of a high voltage electric device. It is a partial perspective view for showing the connection state of the part 30 and the terminal on the battery pack 100 side. (A) is a partial perspective view showing the shapes of the positive electrode terminals (162 and 172) and the negative electrode terminals (167 and 177), and a diagram showing a connection circuit at the time of low voltage output, and (B) is a terminal of a low voltage electric device. It is a partial perspective view for showing the connection state of the part 80 and the terminal on the battery pack 100 side. It is a block diagram which shows the basic internal circuit of a battery pack 100. It is a circuit diagram of the electric equipment (power tool main body 1) for high voltage to which the battery pack 100 of this Example is connected. It is a figure which shows the example of the operation mode of the current consumption control means 195. It is a flowchart which shows the current consumption control for adjusting the voltage balance of the battery pack 100 which concerns on this Example. It is a flowchart which shows the current consumption control for adjusting the voltage balance of the battery pack 100 which concerns on 2nd Embodiment.

Hereinafter, examples of the present invention will be described with reference to the drawings. In the following figures, the same parts are designated by the same reference numerals, and the repeated description will be omitted. In this specification, an electric tool operated by a battery pack will be used as an example of an electric device.

FIG. 1 is a diagram for explaining a state in which the battery pack according to the present embodiment is attached to the power tool. There are various types of power tools, which are a form of electric equipment. In addition to the power tools that use the currently widely used battery pack with a rating of 18V, the battery pack 100 with a rating of 36V that can obtain higher output. Power tools using the above are commercially available. Further, a battery pack that can be attached to either the power tool main body 51 having a rating of 18 V or the power tool main body 1 having a rating of 36 V is commercially available depending on the applicant.

The

power tool bodies

1 and 51 shown in FIG. 1 are both called impact tools. The

power tool bodies

1 and 51 are tools in which tip tools such as bits (not shown) are attached to output shafts 9 and 59, and tightening work is performed by applying a rotational force or a striking force in the axial direction to the tip tools. Here, hexagonal holes (not shown) having a hexagonal cross section are formed on the output shafts 9 and 59, and one-

touch mounting mechanisms

8 and 58 are provided. The

power tool bodies

1 and 51 include

housings

2 and 52 which are outer frames forming an outer shape. The

housings

2 and 52 are formed with substantially

tubular body portions

2a and 52a and handle

portions

2b and 52b extending in the orthogonal direction (downward) from the vicinity of the axial center of the

body portions

2a and 52a. Trigger-shaped operation switches 4 and 54 are provided in the vicinity of the

handle portions

2b and 52b where the index finger hits when the operator grips the

handle portions

2b and 52b. In the vicinity of the operation switches 4 and 54, forward /

reverse switching levers

5 and 55 for switching the rotation directions of the output shafts 9 and 59 are provided. Battery

pack mounting portions

2c and 52c for mounting the battery pack 100 are formed below the

handle portions

2b and 52b.

The power tool main body 51 is an electric device that uses a battery pack having a rated voltage of 18 V. The power tool main body 1 is an electric device main body that uses a battery pack having a rated voltage of 36 V. The conventional battery pack dedicated to 36V contains only one set of cell units in which 10 cells of a lithium-ion battery rated at 3.6V are connected in series. In the battery pack 100 of this embodiment, two sets of cell units formed by connecting five cells of a lithium ion battery rated at 3.6V in series are accommodated, and these two cell units are connected in series. The rated output of 36V was obtained, and the rated output of 18V was obtained by connecting in parallel other than the series connection state. In the present specification, the voltage of 18V is referred to as "low voltage" in the sense that the voltage is lower than the voltage of 36V, and 36V is referred to as "high voltage".

In the battery pack 100 of this embodiment, by devising the terminal configuration on the battery pack 100 side and the terminal configuration on the terminal portion 30 on the device side of the power tool body 1 for 36V, the power tool body 51 can also be the power tool body. I made it possible to attach it to 1. Further, when the battery pack 100 is attached to the power tool body 51 for 18V as shown by arrow a1, the output of the battery pack 100 is automatically set to 18V, and when it is attached to the power tool body 1 for 36V as shown by arrow a2, the battery pack 100 is automatically attached. The output of 100 automatically becomes 36V. That is, by mounting the battery pack 100 on either the power tool

main body

1 or 51, the output voltage is switched to match the mounted power tool main body.

FIG. 2 is a perspective view of the battery pack 100 according to the embodiment of the present invention. The battery pack 100 can be mounted and removed from the battery

pack mounting portions

2c and 52c (see FIG. 1). Further, in order to have compatibility with the conventional battery pack for rating 18V in terms of mounting, the shape of the mounting portion of the battery pack 100 is the same as that of the conventional battery pack. The housing of the battery pack 100 is formed by a lower case 101 and an upper case 110 that can be divided in the vertical direction. The upper case 110 is formed with a mounting mechanism in which two

rail grooves

138a and 138b are formed for mounting on the battery pack mounting portion 2c. The

rail grooves

138a and 138b are formed so as to extend in a direction parallel to the mounting direction of the battery pack 100 and to project to the left and right side surfaces of the upper case 110. The

rail grooves

138a and 138b are formed in a shape corresponding to a rail (not shown) formed in the battery pack mounting portion 2c of the power tool main body 1, and the

rail grooves

138a and 138b are fitted with the rail on the electric device main body side. In this state, the battery pack 100 is fixed to the

power tool bodies

1 and 51 by locking with the locking portion 142 which is the claw of the latch 141. When removing the battery pack 100 from the

power tool bodies

1 and 51, by pushing the latches 141 on both the left and right sides, the locking portion 142 moves inward and the locked state is released. Therefore, the battery pack 100 is released in that state. Move 100 to the side opposite to the mounting direction.

The lower surface 111 and the upper surface 115 of the upper case 110 are formed in a stepped shape, and a plurality of slots 121 to 128 extending rearward from the connecting portion thereof are formed. Slots 121 to 128 are notched portions so as to have a predetermined length in the battery pack mounting direction, and inside the notched portions, the power tool

main bodies

1, 51 or an external charging device ( A plurality of connection terminals that can be fitted with the device-side terminals (not shown) are arranged. In slots 121 to 128, the slot 121 on the right side of the battery pack 100 near the rail groove 138a serves as an insertion port for the positive electrode terminal (C + terminal) for charging, and the slot 122 serves as an insertion port for the positive electrode terminal (+ terminal) for discharging. Become. Further, the slot 127 on the side closer to the rail groove 138b on the left side serves as an insertion port for the negative electrode terminal (-terminal). Between the positive electrode terminal and the negative electrode terminal, a plurality of signal terminals for transmitting signals to the battery pack 100 and the

power tool bodies

1 and 51 and an external charging device (not shown) are arranged, and here, for signal terminals. Four slots 123-126 are provided between the power terminals. The slot 123 is a spare terminal insertion slot, and no terminal is provided in this embodiment. The slot 124 is an insertion port for a T terminal for outputting a signal serving as identification information of the battery pack 100 to the power tool main body or the charging device. Slot 125 is an insertion slot for a V terminal for inputting a control signal from an external charging device (not shown). The slot 126 is an insertion port for an LS terminal for outputting battery temperature information by a thermistor (temperature sensitive element) (not shown) provided in contact with the cell. On the left side of the slot 127 which is the insertion port of the negative electrode terminal (-terminal), a slot 128 for the LD terminal which outputs an abnormal stop signal by the battery protection circuit (not shown) included in the battery pack 100 is further provided. ..

On the rear side of the upper surface 115, a raised portion 132 formed so as to be raised is formed. A recessed stopper 131 is formed near the center of the raised 132. The stopper portion 131 becomes a contact surface when the battery pack 100 is mounted on the battery

pack mounting portions

2c and 52c. When the battery pack 100 is mounted at a predetermined position on the

power tool bodies

1 and 51, a plurality of terminals (device side terminals) arranged on the

power tool bodies

1 and 51 and a plurality of connections arranged on the battery pack 100. The terminals come into contact and become conductive.

FIG. 3A is a partial perspective view showing the shapes of the positive electrode terminals (162 and 172) and the negative electrode terminals (167 and 177) of this embodiment, and FIG. 3B is a diagram showing a connection circuit at the time of high voltage output. It is a partial perspective view for showing the connection state of the terminal part 30 of the electric apparatus for high voltage, and the terminal of a battery pack 100 side. As shown in FIG. 3A, two positive electrode terminals and two negative electrode terminals of the battery pack 100 of this embodiment are provided in order to realize the voltage variable battery pack. The positive electrode terminal is composed of an upper positive electrode terminal 162 and a lower positive electrode terminal 172, and is arranged in the slot 122 shown in FIG. Similarly, the negative electrode terminal is composed of an upper negative electrode terminal 167 and a lower negative electrode terminal 177, and is arranged in the slot 127 shown in FIG. The number of connection terminals other than the positive electrode terminal and the negative electrode terminal, that is, the T terminal, V terminal, LS terminal, and LD terminal (none of which are shown) of slots 124 to 126 and 128 is one.

In the inner space where the slot 122 is provided, the upper positive electrode terminal 162 and the lower positive electrode terminal 172 are arranged side by side at the upper limit. The upper positive electrode terminal 162 and the lower positive electrode terminal 172 are formed by pressing a metal plate, and the legs are firmly fixed to the circuit board 150 by soldering or the like. The upper positive electrode terminal 162 and the lower positive electrode terminal 172 are arranged at a distance from each other and are in an electrically non-conducting state. Similarly, the upper negative electrode terminal 167 and the lower negative electrode terminal 177 are arranged side by side in the inner space where the slot 127 is provided. The upper positive electrode terminal 162 and the upper negative electrode terminal 167, and the lower positive electrode terminal 172 and the lower negative electrode terminal 177 are the same metal parts.

Inside the battery pack 100, an upper cell unit (first cell unit) 146 and a lower cell unit (second cell unit) 147 in which five lithium ion battery cells are connected in series are housed, and the upper cell unit is accommodated. The positive electrode of 146 is connected to the upper positive electrode terminal 162 corresponding to the first positive electrode terminal, and the negative electrode of the upper cell unit 146 is connected to the lower negative electrode terminal 177 corresponding to the first negative electrode terminal. Similarly, the positive electrode of the lower cell unit 147 is connected to the lower positive electrode terminal 172 corresponding to the second positive electrode terminal, and the negative electrode of the lower cell unit 147 is connected to the upper negative electrode terminal 167 corresponding to the second negative electrode terminal. To. In such a form of the battery pack 100, the positive electrode input terminal on the power tool body 1 side is connected to the upper positive electrode terminal 162, the negative electrode input terminal is connected to the upper negative electrode terminal 167, and the lower side is shown by the dotted line 39. If the side positive electrode terminal 172 and the lower negative electrode terminal 177 are electrically connected, the output of the series connection of the upper cell unit 146 and the lower cell unit 147, that is, the rated value of 36 V, is from the battery pack 100 to the load device 40 of the power tool body 1. Will be output to. Here, the upper cell unit 146 is referred to as a high voltage side (high potential side) cell unit, and the lower cell unit 147 is referred to as a low voltage side (ground side) cell unit.

FIG. 3B is a diagram showing a connection relationship between the terminal portion 30 of the power tool main body 1 having a rating of 36 V and the connection terminals (162, 167, 172, 177) on the battery pack 100 side. The terminal portion 30 is provided in the battery pack mounting portion 2c of the power tool main body 1. The terminal unit 30 is provided with device-side terminals (32, 39a, 34 to 36, 37, 39b, 38) corresponding to slots 121 to 128 (see FIG. 2) of the battery pack 100, and is made of a synthetic resin base. It is fixed so as to be cast in 31. The short-circuit circuit 39 can be composed of a short-circuit element made of a metal plate, and as shown in FIG. 3, the short-circuit circuit 39 is U-shaped on a synthetic resin base 31 together with other device-side terminals such as the positive electrode input terminal 32 and the negative electrode input terminal 37. It can be constructed by casting a metal plate bent into a shape. One end of the U-shaped bent metal plate serves as a short-circuit terminal 39a, and the other end serves as a short-circuit terminal 39b. The upper connection terminal portion of the base 31 and the lower plate-shaped terminal portion having the same reference numeral are composed of an electrically conductive metal plate. Here, the device-side terminal is not provided at the position corresponding to the slot 123 (see FIG. 2). As input terminals for electric power, the positive electrode input terminal 32 and the negative electrode input terminal 37 for receiving power are configured in a small size, and are provided above the short-

circuit terminals

39a and 39b, respectively. The positive electrode input terminal 32 and the short-circuit terminal 39a are not conducting with each other. Further, the negative electrode input terminal 37 and the short-circuit terminal 39b are not conducting with each other.

When the battery pack 100 is attached, the positive electrode input terminal 32 is fitted only to the upper positive electrode terminal 162, and the negative electrode input terminal 37 is fitted only to the upper negative electrode terminal 167. Further, since the terminal portion 30 of the power tool main body 1 is provided with

small terminals

39a and 39b for short-circuiting the lower positive electrode terminal 172 and the lower negative electrode terminal 177, the lower positive electrode terminal 172 and the lower terminal 172 are provided when the battery pack 100 is attached. The side negative electrode terminal 177 is electrically connected by the short circuit 39.

The positive electrode input terminal 32 is a portion that fits with the upper positive electrode terminal 162 and connects the terminal portion formed in a flat plate shape to the circuit board side of the power tool main body 1 side, and is a base 31. It is composed of terminals protruding upward. The positive electrode input terminal 32 is cast into a base 31 made of synthetic resin. The negative electrode input terminal 37 is the same as the positive electrode input terminal 32, and the height of the terminal plate is set to be slightly smaller than half that of the other terminal (34 to 36, 38) plates. The other terminals (34 to 36, 38) are terminals for signal transmission.

Recesses

31a and 31b for being sandwiched by the housing 2 are provided on the front side and the rear side of the synthetic resin base 31 of the terminal portion 30.

In FIG. 3B, when the battery pack 100 is mounted, when the battery pack 100 is relatively moved with respect to the power tool main body 1 along the insertion direction, the positive electrode input terminal 32 and the short-circuit terminal 39a are the same. It is inserted all the way through the slot 122 (see FIG. 3) and fitted into the upper positive electrode terminal 162 and the lower positive electrode terminal 172, respectively. At this time, the positive electrode input terminal 32 is press-fitted between the

arms

162a and 162b of the upper positive electrode terminal 162 so as to spread between the fitting portions of the upper positive electrode terminal 162, and the short-circuit terminal 39a is the lower positive electrode terminal 172. It is press-fitted so as to spread between the

arms

172a and 172b. Similarly, the negative electrode input terminal 37 and the short-circuit terminal 39b are inserted into the inside through the same slot 127 (see FIG. 2), and are fitted into the upper negative electrode terminal 167 and the lower negative electrode terminal 177, respectively. At this time, the negative electrode input terminal 37 is press-fitted between the

arm portions

167a and 167b of the upper negative electrode terminal 167 so as to spread between the fitting portions. Further, the short-circuit terminal 39b is press-fitted so as to spread between the

arm portions

177a and 177b of the lower negative electrode terminal 177. As described above, by realizing the connection form of FIG. 3B, the output of the series connection of the upper cell unit 146 and the lower cell unit 147, that is, the rated value of 36V is output from the battery pack 100.

4 (A) and 4 (B) are diagrams showing a connection state when the battery pack 100 of this embodiment is attached to the conventional power tool main body 51 for 18V (see FIG. 1). The positive electrode input terminal 82 and the negative electrode input terminal 87 have the same shape as the other connection terminals, and have the same height in the vertical direction. When the battery pack 100 is attached to the power tool main body 51, the terminal portion of the positive electrode input terminal 82 is fitted and press-fitted so as to spread both the upper positive electrode terminal 162 and the open end portion of the lower positive electrode terminal 172. A part of the upper side of the terminal portion of the positive electrode input terminal 82 comes into contact with the upper positive electrode terminal 162, and a part of the lower side comes into contact with the lower positive electrode terminal 172. By simultaneously fitting the terminal portion of the positive electrode input terminal 82 to the

arm portions

162a and 162b of the upper positive electrode terminal 162 and the

arm portions

172a and 172b of the lower positive electrode terminal 172, the two positive electrode terminals (162 and 172) are fitted. Is short-circuited. Similarly, the terminal portion of the negative electrode input terminal 87 is fitted and press-fitted so as to push out both the upper negative electrode terminal 167 and the open end portion of the lower negative electrode terminal 177, and the upper portion of the terminal portion of the negative electrode input terminal 87. Region is in contact with the upper negative electrode terminal 167, and a part of the lower region is in contact with the lower negative electrode terminal 177. By simultaneously fitting the terminal portion of the negative electrode input terminal 87 to the

arm portions

167a and 167b of the upper negative electrode terminal 167 and the

arm portions

177a and 177b of the lower negative electrode terminal 177, the two negative electrode terminals (167 and 177) are fitted. Is short-circuited, and the output of the parallel connection of the upper cell unit 146 and the lower cell unit 147 to the power tool main body 51, that is, the rated 18V is output from the battery pack 100 to the load device 90 of the power tool main body 51. ..

As described above, the output of the battery pack 100 is automatically switched by mounting the battery pack 100 of the present embodiment on either the power tool main body 51 for 18V or the power tool main body 1 for 36V. Since this voltage switching is not performed on the battery pack 100 side but automatically depending on the shape of the terminal portion on the power tool

main bodies

1 and 51 side, there is no possibility that a voltage setting error will occur. Further, since it is not necessary to provide a dedicated voltage switching mechanism such as a mechanical switch on the battery pack 100 side, the structure is simple, the risk of failure is low, and a long-life battery pack can be realized.

When the battery pack 100 is charged using an external charging device (not shown), it can be charged with the same charging device as the conventional 18V battery pack. Since the slot 121 of the battery pack 100 is provided with a positive electrode terminal for charging having the same shape as the upper positive electrode terminal 162 and the lower positive electrode terminal 172, it is used for charging instead of the positive electrode terminals for discharging (162, 172). The positive electrode terminal (not shown) of the above may be connected to the positive electrode terminal of the external charging device (not shown). As described above, the battery pack 100 is charged by using the charging device for 18V with the upper cell unit 146 and the lower cell unit 147 connected in parallel. Therefore, when charging the battery pack 100 of the present embodiment, the battery pack 100 is charged. It has the advantage of not having to prepare a new charging device.

FIG. 5 is a block diagram showing an internal circuit of the battery pack 100 of this embodiment. Here, only the basic components for explaining the connection status of the microcomputer 190 and the

protection ICs

151 and 181 to the upper cell unit 146 and the lower cell unit 147 are shown, and other related circuits, particularly the main body, are shown. The illustration of the circuit for communicating with the signal terminal on the device side is omitted. As shown in FIG. 3, the battery pack 100 includes an upper positive electrode terminal (upper +) 162, a lower positive electrode terminal (lower +) 172, an upper negative electrode terminal (upper-) 167, and a lower negative electrode terminal (lower). +) 177 and LD terminal 168 are included. In addition to these, the battery pack 100 is provided with an upper positive electrode terminal (upper +) for charging, a lower positive electrode terminal 172, and other signal terminal groups (T terminal, V terminal, LS terminal). The illustrations thereof are omitted. The output of the upper cell unit 146 is connected to the upper positive electrode terminal 162 and the lower negative electrode terminal 177. That is, the positive electrode (+ output) of the upper cell unit 146 is connected to the upper positive electrode terminal 162, and the negative electrode (− output) of the upper cell unit 146 is connected to the lower negative electrode terminal 177. Similarly, the positive electrode (+ output) of the lower cell unit 147 is connected to the lower positive electrode terminal 172, and the negative electrode (− output) of the lower cell unit 147 is connected to the upper negative electrode terminal 167.

Protection ICs

151 and 181 for monitoring the voltage of the battery cell are connected to the upper cell unit 146 and the lower cell unit 147, respectively, and the microcomputer 190 is connected to these

protection ICs

151 and 181. The protection IC 151 executes a cell balance function, a cascade connection function, and a disconnection detection function in addition to an overcharge protection function and an overdischarge protection function by inputting a voltage across each battery cell of the upper cell unit 146. It is an integrated circuit commercially available as a "protection IC for a lithium ion battery". Further, when the voltage of the battery cell of the upper cell unit 146 drops below a predetermined value and becomes an over-discharged state, the protection IC 151 outputs a signal (high signal) 156 indicating over-discharge to the microcomputer 190 to output the upper side. When the voltage of the battery cell of the cell unit 146 reaches a predetermined value or more at the time of charging and becomes an overcharged state, a signal (high signal) 155 indicating overcharge is output to the microcomputer 190.

A protective IC 181 is connected to the lower cell unit 147. Here, the microcomputer 190 is further provided in the circuit of the lower cell unit 147, that is, in the circuit between the lower positive electrode terminal 172 and the upper negative electrode terminal 167. That is, the protection IC 151 is arranged in the circuit provided in parallel with the upper cell unit 146, whereas the protection IC 181 and the microcomputer (MicroControllerUnit) 190 are arranged in the circuit provided in parallel with the lower cell unit 147. Be placed. The output from the protection IC 151 (overdischarge signal 156, overcharge signal 155) and the output from the protection IC 181 (overdischarge signal 186, overcharge signal 185) are input to the microcomputer 190. The microcomputer 190 includes, for example, a voltage detection circuit called an analog front end (AFE), and measures the current value flowing from the output voltage of the current detection circuit 183 to the lower cell unit 147. The voltage adjustment of each battery cell included in the upper cell unit 146 and the lower cell unit 147 is performed by the respective protection ICs (151, 181). The microcomputer 190 adjusts the voltage balance between the upper cell unit 146 and the lower cell unit 147 in which the voltage of each battery cell is adjusted.

The power supply for driving the microcomputer 190 is generated by the power supply circuit (power supply unit) 187 connected to the lower cell unit 147, and the reference voltage (VDD1) is supplied to the microcomputer 190. A shunt resistor 182 for measuring the current value is provided on the ground side of the lower cell unit 147.

The microcomputer 190 monitors the current value and the cell temperature, and also monitors the states of the upper cell unit 146 and the lower cell unit 147 to integrate and control the operating status of both. Further, when the power tool main body 1 needs to be stopped urgently, the discharge prohibition signal 188 is transmitted to the electric device main body side via the LD terminal 168. The protection IC 181 monitors the voltage of the battery cell in the lower cell unit 147, and sends an over-discharge signal 186 to the microcomputer 190 when it detects a state in which the voltage drops to a predetermined lower limit value (over-discharge state). Further, when the battery pack 100 is attached to an external charging device (not shown) and charging is performed, the protection IC 181 detects that the voltage of the battery cell exceeds a predetermined upper limit value, and is overcharged. The overcharge signal 185 indicating the state is sent to the microcomputer 190. The microcomputer 190 sends a charge stop signal to a charging device (not shown) via an LS terminal (not shown).

The microcomputer 190 is provided with a wireless communication means 192 using Bluetooth (Bluetooth: Bluetooth SIG, Inc. USA registered trademark). The wireless communication means 192 performs wireless communication with an external device registered for pairing under the control of the microcomputer 190, and includes an antenna unit (not shown). A storage unit 191 is connected to the microcomputer 190 to appropriately store information transmitted / received after pairing with an external device and pairing. The battery pack 100 is provided with a pairing switch (not shown), and when an operator presses the pairing switch, the microcomputer 190 executes a pairing registration process with an external device. With the above configuration, the battery pack 100 can perform bidirectional communication with an external device using wireless communication means. Through this communication, the external device can obtain management information from the battery pack 100 and analyze the state of the battery pack 100 using a predetermined algorithm.

The cell temperature detecting means 193 is connected to the microcomputer 190. Outputs of a plurality of temperature sensors (not shown) are connected to the cell temperature detecting means 193. As the temperature sensor, a thermistor can be used, and one or more thermistors are provided at a location in contact with or close to the upper cell unit 146, and another thermistor is provided at a location in contact with or close to the lower cell unit 147. .. The cell temperature detecting means 193 measures the temperatures of the upper cell unit 146 and the lower cell unit 147 by utilizing the change in the electric resistance of the thermistor with respect to the temperature change, and outputs the temperature to the microcomputer 190.

The power supply circuit 187 uses the electric power of the lower cell unit 147 to generate a power supply for operating the microcomputer 190. Since the battery pack 100 of this embodiment is a voltage switching type of 18V and 36V, if a microcomputer is mounted on the protection circuit on the upper cell unit 146 side, the ground of the microcomputer 190 is used when the two cell units are connected in series and in parallel. The potential changes. On the other hand, if the power supply circuit 187 is provided on the lower stage side, the ground potential of the power supply circuit 187 does not change. Therefore, in this embodiment, the microcomputer 190 is provided not in the circuit of the upper cell unit 146 but in the circuit of the lower cell unit 147. By arranging the microcomputer 190, the microcomputer 190 can be operated stably even if the output voltage is switched between the rated voltage of 18V and 36V. The microcomputer 190 can switch between holding and releasing the power supply voltage (VDD ₁ ) applied to itself, and can switch between a normal operation state (normal mode), an operation function limited state (so-called sleep mode), and an operation stop state (so-called shutdown). Have.

The output of the upper voltage detection circuit 189 connected to the upper positive electrode terminal 162 is input to the microcomputer 190. This output indicates the potential of the upper cell unit 146 when the battery pack 100 is not mounted on the

power tool bodies

1, 51 or an external charging device (not shown). On the other hand, when mounted on the power tool body 1 for low voltage (18V), the upper positive electrode terminal 162 and the lower positive electrode terminal 172 are connected, so that the positive electrodes of the upper cell unit 146 and the lower cell unit 147 are connected to each other. The potentials are the same, and each negative electrode has the same potential. From this, the microcomputer 190 compares the potential of the upper positive electrode terminal 162 with the potential of the lower positive electrode terminal 172 to determine whether the battery pack 100 is not mounted or is mounted on the low voltage device main body. It is possible to determine whether or not it is attached to a high-voltage device. In order to detect the potential of the lower positive electrode terminal 172, it is preferable that the microcomputer 190 can acquire the positive electrode potential of the uppermost battery cell 147a among the battery cells in the lower cell unit 147. When the power supply from the battery pack 100 must be stopped, for example, when an excessive current during discharge, a decrease in cell voltage during discharge (overdischarge), an abnormal rise in cell temperature (overtemperature), etc. occur. By transmitting the discharge prohibition signal 188 to the power tool main body side via the microcomputer 190, the operations of the power tool

main bodies

1 and 51 can be stopped quickly. The discharge prohibition signal 188 is transmitted by dropping the LD terminal 168 to the ground potential by making the switching element 184 conductive by outputting a high signal from the I / O port of the microcomputer 190.

With the above configuration, the battery pack 100 capable of automatically switching the output voltage (connection form of the cell unit) can be realized. However, in the basic configuration of this embodiment, the lower cell unit 147 supplies the power consumption of the microcomputer 190, the power consumption of the wireless communication means 192, and the power consumption of the cell temperature detecting means 193. The total power consumption of 147 becomes larger than the total power consumption of the upper cell unit 146. It is not preferable that the unbalanced state of power consumption continues for a long time because the potential on the lower cell unit 147 side becomes lower than that on the upper cell unit. This is because when the upper cell unit 146 and the lower cell unit 147 are connected in parallel to output a rated value of 18 V, a circulating current flows due to a voltage imbalance between the cell units immediately after the parallel connection state is established. Therefore, in this embodiment, the current consumption control means 195 for adjusting the amount of current consumption with the lower cell unit 147 is provided in the circuit of the upper cell unit 146 with low power consumption. The current consumption control means 195 is interposed in parallel with the lower power consumption side of the two cell units, here the upper cell unit 146, and is configured as a load circuit different from the integrated protection IC 151. To.

The current consumption control means 195 operates according to an instruction from the microcomputer 190. The microcomputer 190 can switch between holding and releasing the power supply voltage (reference voltage VDD ₁ ) applied to itself, and is in a normal operating state (normal mode), an operating function limited state (so-called sleep mode), and an operation stopped state (so-called shutdown). ). Since the power supply circuit 187 of the microcomputer 190 is shared with the protection IC 181, when the microcomputer starts up, the protection IC 181 also starts up at the same time. Further, when the reference voltage VDD ₁ becomes high, the source and drain of the switching element 154 become conductive, so that the power ON / OFF port of the protection IC 151 is grounded and the protection IC 151 is activated.

The current consumption control means 195 is an electric circuit (discharge circuit) composed of a resistance portion by a resistor and a switch portion by a switching element 197. As for the resistance portion, the resistance value of the resistor 196 is about several hundred Ω. Here, a resistor 196 that serves as a pseudo load is connected between both terminals of the upper cell unit 146, and its circuit is turned on or off by a switching element 197 that is a switch unit. The gate terminal of the switching element 197 is connected to the I / O terminal of the microcomputer 190. One end of the resistor 196 is connected to the positive electrode output of the upper cell unit 146, and the other end is connected to the drain terminal of the switching element 197. The source terminal of the switching element 197 is connected to the ground line of the upper cell unit 146. The switching element 197 is turned on or off by the control signal 194 from the microcomputer 190. In the current consumption control means 195, the gate potential of the switching element 197 is 0 V when the instruction from the microcomputer 190 is off. Then, the switching element 197 is turned off. When the switching element 197 is in the OFF state, the current path to the resistor 196 is cut off, so that the power consumption by the current consumption control means 195 is zero. In this circuit diagram, although it is briefly shown to show the basic principle of the current consumption control means 195, a circuit in which a plurality of switching elements are provided to stabilize the switching operation or the switching element 197 is a P channel instead of an N channel. It is sufficient if the desired power consumption can be achieved even if various changes are made by changing the size of the resistor and the installation position.

As described above, by providing the current consumption control means 195, the surplus power consumption on the lower cell unit 147 side can be similarly consumed in the circuit of the upper cell unit 146. Further, since the switching between the movable and stopped current consumption control means 195 can be arbitrarily controlled from the microcomputer 190, the microcomputer 190 can perform highly accurate power balance adjustment between the cell units.

There are three stages of the state of the microcomputer 190: normal, sleep, and shutdown. Normal is a state in which the microcomputer 190 is always running. Sleep is a mode in which the operation of the functions of the external circuit and the microcomputer 190 itself is restricted to the minimum, and the microcomputer 190 starts up intermittently by itself. For example, the operation of stopping for 240 milliseconds after starting for 10 milliseconds is repeated. .. Shutdown is a state in which the reference voltage VDD ₁ is not supplied at all, and the microcomputer 190 is completely stopped. The microcomputer 190 can operate not only when the battery pack 100 is attached to the power tool main body 1 but also when it is not attached. However, when the battery pack 100 is not installed, or when the power tool has not been used for a certain period of time even when it is installed, for example, the trigger operation is performed for about 2 hours after the trigger operation of the electric device main body is completed. If this is not done, the microcomputer 190 goes to sleep. When the operation switch 4 of the power tool main body 1 is pulled again and a current flows through the motor 3, the microcomputer 190 detects an increase in the current value detected by the current detection circuit 183 and returns to the normal state.

In this embodiment, when the microcomputer 190 is included in only one of the protection circuits of the plurality of cell units, the potential difference between the plurality of cell units is increased by leaving the battery pack for a long period of time. The problem was solved by adding the current consumption control means 195 to the protection circuit of another cell unit in which the microcomputer 190 is not provided. Further, the operation or stop of the current consumption control means 195 can be arbitrarily controlled by the discharge control signal 194 from the microcomputer 190. In this configuration, the microcomputer 190 compares its own operation mode and peripheral circuits (wireless communication means) using the lower cell unit 147 as a power source while comparing the actual voltage of the upper cell unit 146 with the voltage of the lower cell unit 147. The current consumption control means 195 is operated according to the power consumption of the cell temperature detection means 193, etc.). As a result, the microcomputer 190 can satisfactorily adjust the balance of the current consumption of each of the plurality of cell units (146, 147), and the voltage balance of each cell unit can be adjusted even after long-term use (especially after storage). We were able to realize a battery pack that does not deteriorate.

FIG. 6 is a circuit diagram of a power tool main body 1 (electric device for high voltage) on which the battery pack 100 is mounted. The right side is the battery pack 100, and the specific circuit configuration is the same as that shown in FIG. As shown in FIG. 3, the terminal portion 30 of the power tool main body 1 having a rating of 36 V includes a short-circuit circuit 39 for short-circuiting the lower positive electrode terminal 172 and the lower negative electrode terminal 177. In this embodiment, the power tool main body 1 is provided with a terminal portion 30 (see FIG. 3) having a short-circuit circuit 39, thereby having two positive electrode terminals (162, 172) and two negative electrode terminals (167, 177). A series connection circuit of the upper cell unit 146 and the lower cell unit 147 can be established only by mounting the battery pack 100 of the above. The power tool main body 1 includes a microcomputer 20 for controlling the rotation of the motor 3. The driving voltage (5V or 3.3V) of the microcomputer 20 is supplied by the power supply circuit 21 that inputs the voltages across the positive electrode input terminal 32 and the negative electrode input terminal 37.

The microcomputer 20 includes, for example, a voltage detection circuit called an analog front end (AFE), and the voltage (V +) of the positive input terminal 32 is input from the battery voltage detection circuit 22 to the input port of the microcomputer 20. The microcomputer 20 outputs a signal for turning on the switching element 25 via the output port (A / D output terminal). The switching element 25 is a switch for stopping the motor 3 under the control of the microcomputer 20 when the discharge prohibition signal is received. The switch (SW) state detection circuit 23 is a circuit that detects whether the state of the operation switch 4 is on or off, and outputs an on signal to the microcomputer 20 when the lever of the operation switch 4 is pulled even a little. The microcomputer 20 inputs / outputs various signals such as various control signals, input signals from sensors, and control signals to the battery pack 100. The current detection circuit 24 outputs the magnitude of the current value to the microcomputer 20 by measuring the voltage across the shunt resistor 26.

The LD terminal 38 is connected to the input / output port of the microcomputer 20 via the resistor 28. The resistor 28 and the microcomputer 20 are connected to the _{reference voltage VDD 2 via the resistor 27.} When the microcomputer 190 on the battery pack 100 side sends (sets high) the discharge prohibition signal 188, the switching element 184 conducts, so that the

LD terminals

146 and 38 are dropped to the ground potential. As a result, the input potential of the microcomputer 20 connected to the resistor 28 changes to the voltage dividing potential of the resistors 27 and 28, so that the microcomputer 20 can detect that the discharge is prohibited.

FIG. 7 is a diagram showing an example of an operation mode of the current consumption control means 195. The vertical axis represents the potential of the control signal 194 input as a gate signal to the switching element 197 of the current consumption control means 195, and the horizontal axis represents the passage of time (unit: seconds). Time T is the unit time to be managed. FIG. 7A shows the operating status of the current consumption control means 195 when the microcomputer 190 is operating normally (normal mode). Here, the control signal 201 is a signal pattern of the control signal 194 in the normal mode, and only the section of the time B, which is about half of the first half of the time T of one cycle, is turned on (gate voltage of the switching element 197 of the current consumption control means 195). Is high, the switching element 197 is conductive and power is consumed by the resistor 196), and the remaining section is turned off of the switching element 197 (the gate voltage of the switching element 197 is a cutoff state of zero). The resistor 196 is in a state where power is not consumed. In the normal mode, the operation of the current consumption control means 195 according to the pattern of the time T of one cycle is intermittently repeated.

FIG. 7B shows the operating status of the current consumption control means 195 when the microcomputer 190 is in the sleep state, and shows the sleep mode. At this time, the control signal 202 operates the current consumption control means 195 with only the first short time C of the time T of one cycle turned on, and most of the remaining power is generated by the non-operating state, that is, the resistor 196. It is in a state where it is not consumed. In the operation mode of FIG. 7B, the power consumption by the current consumption control means 195 is reduced to about 1/40 of that of FIG. 7A. In the sleep state, the microcomputer 190 operates for about the same time as the first short time C, or for a time slightly longer than the time C, and is inactive at other times.

FIG. 7C shows an operating status of the current consumption control means 195 in a state in which the microcomputer 190 is operating normally and the wireless communication means 192 (see FIG. 5) is being operated (wireless). Communication mode). Here, the total time (= time A) is obtained by adding the power consumption of the microcomputer 190 consumed in the normal mode (time B minutes in FIG. 7A) and the power consumption increased by the wireless communication means 192. To do. This time A is about 70% of the time T of one cycle. In this way, under the control of the microcomputer 190, the electric power consumed for the operation of the control unit in the lower cell unit 147 can be discharged from the upper cell unit 146 by the current consumption control means 195.

FIG. 7D shows a state in which the current consumption control means 195 is continuously operated. Here, the switching element 197 of the current consumption control means 195 is continuously turned on in the entire section of the time T of one cycle, and the current consumption control means 195 is continuously operated.

Next, the current consumption control flow for adjusting the voltage balance of the battery pack 100 according to the present embodiment will be described with reference to the flowchart of FIG. The procedure of this flowchart is executed when the microcomputer 190 is running, and is executed until the microcomputer 190 is stopped (shut down). When the microcomputer 190 operates in the sleep mode, this flowchart is executed only while the microcomputer 190 is running.

The current consumption control flow is a control in which the microcomputer 190 operates the current consumption control means 195 to consume the power of the upper cell unit 146 to match the voltage of the lower cell unit 147. When the microcomputer 190 is started, the microcomputer 190 executes the program of the procedure of FIG. 8 stored in a storage means (not shown) (step 220). First, the microcomputer 190 compares the voltages of the

cell units

146 and 147, and determines whether or not the voltage of the upper cell unit 146 is higher than the voltage of the lower cell unit 147 by a predetermined value or more (step 221). If it is higher than a predetermined value, it means that the voltage of the upper cell unit 146 and the voltage of the lower cell unit 147 have a large deviation. Therefore, the current consumption control is performed so as to obtain the discharge pattern shown in FIG. 7 (D). A parameter indicating the time for turning on the means 195, that is, the discharge time X is set to T (step 225), and the process proceeds to step 228. Here, T is the “managed unit time” shown in FIG. 7, for example, in units of several hundred mm seconds.

When the difference between the voltage of the upper cell unit 146 and the voltage of the lower cell unit 147 is less than a predetermined value, it is determined whether or not the wireless communication mode is being executed by the microcomputer 190 (step 222). When the wireless communication mode is being executed, the discharge time X is set to A (step 226), and the process proceeds to step 228. If the wireless communication mode is not being executed, the process proceeds to step 223. In step 223, it is determined whether or not the operation mode of the microcomputer 190 is in the normal mode, and in the case of the normal mode, the discharge time X is set to B (step 227), and the process proceeds to step 228. If the mode is not the normal mode in step 223, that is, in the sleep mode, the discharge time X is set to C (step 224).

Next, it is determined whether or not the value of the time counter t of the microcomputer 190 has not reached the management target unit time T (step 228). Immediately after the microcomputer 190 is started and steps 221 to 224 are first executed, t = 0, so t <T becomes true (YES), and “1” is incremented to t in step 229. (Step 229). “1” is a count unit of the time counter t, for example, in mm seconds. If the time counter t becomes equal to T in step 228, the determination in step 228 becomes NO, so the process proceeds to step 230 and the time counter t is cleared to 0.

Next, it is determined whether or not the value of the time counter t of the microcomputer 190 has reached the discharge time X at which the discharge time ends (step 231). When the discharge time X has not been reached, the current consumption control means 195 is turned on or kept on (step 232), and the process returns to step 221. After reaching the discharge time X, the current consumption control means 195 is turned off, and the process returns to step 221.

By repeating the above control, the microcomputer 190 operates the current consumption control means 195 during the first half of the managed unit time T, and the current consumption control means 195 is stopped during the second half after the time X. According to this embodiment, since the current consumption control means 195 is finely operated by the microcomputer 190, it is possible to accurately adjust the voltage between the cell units and to increase the degree of freedom in power management of the battery pack. It got higher. In particular, since the operation and stop of the current consumption control means 195 are controlled by software by the microcomputer 190, highly accurate control is possible. In the control of this embodiment, the upper cell unit 146 and the lower cell unit 147 are provided, and the upper cell unit 146 and the lower cell unit 147 are electrically connected for the first time when they are mounted on the main body of the electric device. As long as the battery pack is such that the battery voltage is fixed, the same can be applied to the battery pack.

Next, the voltage balance adjusting procedure of the battery pack 100 according to the second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the discharge time X setting method of the first embodiment is set in detail according to the state of the peripheral devices (for example, circuits A to C) connected to the microcomputer 190. is there. Here, steps 250 to 255 in the latter half shown by the dotted line are the same as steps 228 to 233 in the flowchart of FIG. This flowchart is executed when the microcomputer 190 is running, and is executed until the microcomputer 190 is stopped (shut down). In the sleep mode, this flowchart is executed only while the microcomputer 190 is running.

First, “a” is set as the initial value of the discharge time X (step 241). “A” is the minimum power consumed by the microcomputer 190, that is, the time required for the current consumption control means 195 to consume the power consumed by the microcomputer 190 during sleep. This is a control for eliminating the imbalance because the microcomputer 190 consumes only the power of the lower cell unit 147 and not the power of the upper cell unit 146. Next, when the circuit A (for example, the wireless communication means 192) using the lower cell unit 147 as the power source is operating, the microcomputer 190 consumes the power consumed by the circuit A by the current consumption control means 195. It is added as the time D required for (steps 242 and 243). When the circuit A is not operating, that is, when it is stopped, the process proceeds to step 244 (step 242).

Next, when the circuit B (for example, the cell temperature detecting means 193) using the lower cell unit 147 as a power source is operating, the microcomputer 190 consumes the power consumed by the circuit B by the current consumption controlling means 195. It is added as the time E required for (steps 244 and 245). When the circuit B is not operating, that is, when it is stopped, the process proceeds to step 246 (step 244). Next, when the circuit C (for example, a battery level indicator lamp (not shown)) using the lower cell unit 147 as a power source is operating, the microcomputer 190 uses the current consumption control means 195 to measure the power consumed by the circuit C. The time F required for consumption is added (steps 246 and 247). When the circuit C is not operating, that is, when it is stopped, the process proceeds to step 248 (step 246).

Next, the microcomputer 190 compares the cell voltages of the

cell units

146 and 147, and determines whether or not the voltage of the upper cell unit 146 is higher than the voltage of the lower cell unit 147 by a predetermined value or more (step 248). If it is higher than a predetermined value, it means that the voltage of the upper cell unit 146 and the voltage of the lower cell unit 147 have a large deviation. Therefore, the current consumption control is performed so as to obtain the discharge pattern shown in FIG. 7 (D). The discharge time X, which is a parameter indicating the time for turning on the means 195, is set to T (step 249). Since the discharge time X = T means that the power consumption of the upper cell unit 146 using the current consumption control means 195 is maximized, the relationship becomes larger than the value set in

steps

243, 245, and 247, that is, T> a + D + E + F.

Next, the current consumption control means 195 is operated or stopped by executing steps 250 to 255 based on the discharge time X of the current consumption control means 195 determined by the procedure of steps 240 to 249. Since the processes of steps 250 to 255 are the same as the processes of steps 228 to 233 shown in FIG. 8, the repeated description will be omitted. Following

steps

254 and 255, the process returns to step 241.

By using the second embodiment, even if additional power consumption circuits other than the circuits A to C are added to the lower cell unit 147 side, the optimum current consumption control means 195 according to the consumption amount thereof. The operation becomes possible, and the power balance of the upper cell unit 146 and the lower cell unit 147 can be satisfactorily adjusted.

Although the present invention has been described above based on Examples, the present invention is not limited to the above-mentioned Examples, and various modifications can be made without departing from the spirit of the present invention. The battery pack 100 of this embodiment is not limited to the one of the voltage switching type, and can be similarly applied as long as it has a plurality of cell units. For example, the present invention is used for adjusting the voltage balance between cell units in a battery pack of a fixed voltage type battery pack in which the outputs of the upper cell unit and the lower cell unit are connected in parallel in the battery pack and output. Can be used. That is, the invention of the present application may have various voltages, various types of secondary batteries, and various housings as long as the battery pack has a plurality of cell units. Further, the type of the electric device main body to which the battery pack 100 is mounted is not limited to the impact tool described in the above embodiment, and the battery pack 100 can be mounted, and the battery pack 100 is used as the main power source. Alternatively, it may be an arbitrary electric device main body that operates as an auxiliary power source.

1 ... Power tool body, 2 ... Housing, 2a ... Body part, 2b ... Handle part, 2c ... Battery pack mounting part, 3 ... Motor, 4 ... Operation switch, 5 ... Forward / reverse switching lever, 8 ... Mounting mechanism, 9 ... Output shaft, 20 ... microcomputer, 21 ... power supply circuit, 22 ... battery voltage detection circuit, 23 ... state detection circuit, 24 ... current detection circuit, 25 ... switching element, 26 ... shunt resistance, 27, 28 ... resistor, 30 ... Terminal unit, 31 ... base, 31a ... concave, 32 ... positive electrode input terminal, 34 ... T terminal, 35 ... V terminal, 36 ... LS terminal, 37 ... negative electrode input terminal, 38 ... LD terminal, 39 ... short circuit, 39a , 39b ... Short-circuit terminal, 40 ... Load device, 51 ... Power tool body, 52 ... Housing, 52a ... Body part, 52b ... Handle part, 52c ... Battery pack mounting part, 80 ... Terminal part, 81 ... Base, 82 ... Positive electrode input terminal, 84 ... T terminal, 85 ... V terminal, 86 ... LS terminal, 87 ... Negative electrode input terminal, 88 ... LD terminal, 90 ... Load device, 100 ... Battery pack, 101 ... Lower case, 110 ... Upper case , 111 ... Lower surface, 115 ... Upper surface, 121-128 ... Slot, 131 ... Stopper, 132 ... Raised part, 138a, 138b ... Rail groove, 141 ... Latch, 142 ... Locking part, 146 ... Upper cell unit, 147 ... Lower cell unit, 147a ... Battery cell, 150 ... Circuit board, 151 ... Protection IC, 154 ... Switching element, 155 ... Overcharge signal, 156 ... Overdischarge signal, 162 ... Upper positive electrode terminal, 162a, 162b ... Arm Unit, 167 ... Upper negative electrode terminal, 167a, 167b ... Arm, 168 ... LD terminal, 172 ... Lower positive electrode terminal, 172a, 172b ... Arm, 177 ... Lower negative electrode terminal, 177a, 177b ... Arm, 181 ... Protection IC, 182 ... shunt resistance, 183 ... current detection circuit, 184 ... switching element, 185 ... overcharge signal, 186 ... overdischarge signal, 187 ... power supply circuit (power supply unit), 188 ... discharge prohibition signal, 189 ... upper voltage Detection circuit, 190 ... Microcomputer, 191 ... Storage unit, 192 ... Wireless communication means, 193 ... Cell temperature detection means, 194 ... (Discharge) control signal, 195 ... Current consumption control means (adjustment unit), 196 ... Resistor, 197. ... Switching element, 201-204 ... Control signal, A ... Reference potential, VDD ₁ ... Reference voltage (of battery pack 100), VDD ₂ ... Reference voltage (of power tool body 1)

Claims

A state in which at least the first and second cell units are provided as cell units in which a plurality of battery cells are connected in series, and the first cell unit is connected to a higher voltage side than the second cell unit. A battery pack configured to switch between a series connection state in which the first and second cell units are connected in series with each other and a connection state other than the series connection state.
A discharge control signal for controlling the discharge of the battery pack can be output by monitoring the state of the battery cells connected to one of the first and second cell units and constituting at least one of the cell units. The configured control unit and
A battery pack including an adjusting unit connected to the other of the first and second cell units and adjusting the power consumption of the other cell unit by a control signal from the control unit.
A power supply unit connected to the control unit and supplying a power supply voltage to the control unit is provided.
The power supply unit is connected to the one cell unit.
The control unit is connected to the power supply unit and the negative electrode of the one cell unit, and the power supply unit generates the power supply voltage from the voltage input from the one cell unit and supplies the power supply voltage to the control unit. The battery pack according to claim 1.
The battery according to claim 2, wherein the power supply unit is connected to the second cell unit, and the power supply voltage is supplied from the second cell unit to the control unit via the power supply unit. pack.
The battery according to any one of claims 1 to 3, wherein the control unit controls the adjustment unit according to its own state or the state of a connecting element connected to the one cell unit. pack.
The adjusting unit is a discharge circuit including a resistance unit connected in parallel with the other cell unit and a switch unit connected in series with the resistance unit.
The battery pack according to claim 4, wherein the control unit controls the switch unit.
The control unit includes at least a normal mode and an operation mode including a sleep mode.
Any one of claims 1 to 5, wherein the control unit controls the power consumption of the other cell unit in the normal mode so as to be larger than in the sleep mode. Battery pack described in.
The control unit includes a wireless communication mode as the operation mode.
The battery pack according to claim 6, wherein the control unit controls the wireless communication mode so that the power consumption of the other cell unit is larger than that in the sleep mode.
Claims 1 to 1, wherein when the voltage difference between the first and second cell units is equal to or greater than a predetermined value, the control unit always operates the adjusting unit until the voltage difference becomes less than a predetermined value. The battery pack according to any one of 7.
The battery according to claim 6 or 7, wherein when the voltage difference between the first and second cell units is less than a predetermined value, the control unit controls the adjustment unit according to the operation mode. pack.
An electric device having the battery pack according to any one of claims 1 to 9 and at least a first electric device main body as an electric device main body that can be connected to the battery pack.
When the battery pack is connected to the first electric device main body, the first and second cell units are connected in series to each other in a series connection state.
An electric device characterized in that when the battery pack is not connected to the first electric device main body, the first and second cell units are electrically independent and disconnected from each other.
An electric device having the battery pack according to any one of claims 1 to 10 and at least a second electric device main body as an electric device main body that can be connected to the battery pack.
When the battery pack is connected to the second electric device main body, the first and second cell units are connected in parallel to each other in a parallel connection state.
An electric device characterized in that when the battery pack is not connected to the second electric device main body, the first and second cell units are electrically independent and disconnected from each other.