Battery pack, electrical device body, and electrical device

Abstract

The invention provides a battery pack, an electrical device body, and an electrical device. According to the present invention, the state of contact between the connection terminal and the device-side terminal can be monitored by the control unit of the battery pack, so that charging or discharging can be immediately stopped upon detecting an abnormality in voltage balance between the plurality of cell units due to poor contact of the terminal unit. A battery pack (100) has cell units (146, 147) in which upper and lower battery cells are connected in series, and is capable of switching the connection state of the cell units (146, 147), and a control unit (350) monitors whether or not there are occurrences of imbalance in voltage between a plurality of cell units and poor contact between the cell units. If contact failure occurs, a signal (an abnormal stop signal (341) or a charging stop signal (441)) for stopping discharging is emitted and output to the electrical device body side, so that charging and discharging are stopped.

Description

[0001] This application is a divisional application of the original application number 201880043060.8, application date July 24, 2018 (priority date July 24, 2017), and the invention name is "Battery Pack and Electrical Equipment Using Battery Pack". Technical Field

[0002] The present invention relates to an electrical device having loads such as a motor and lighting, and a battery pack for supplying power to the electrical device. Background Art

[0003] Electric tools and other electrical equipment will be driven by battery packs using secondary batteries such as lithium ion batteries, and the cord-less nature of electrical equipment is being promoted. For example, in a handheld electric tool that drives a front tool with a motor, a battery pack containing multiple secondary battery cells is used, and the motor is driven by the electric energy stored in the battery pack. The battery pack is detachably mounted on the power tool body, and once the voltage drops due to discharge, the battery pack is removed from the power tool body and charged using an external charging device.

[0004] In cordless power tools or electrical equipment, it is required to ensure a specified operating time or a specified output. With the improvement of the performance of secondary batteries, high output or high voltage is gradually realized. In addition, with the development of electrical equipment that uses battery packs as power sources, battery packs of various voltages have been commercialized. Usually, the output voltage of a battery pack is fixed, but Patent Document 1 proposes a power supply device for electrical equipment, which has a plurality of battery units in a housing that accommodates the battery, and can select whether to connect them in series for output or in parallel for output through connecting components, thereby supporting equipment with different voltages.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-17954 Summary of the invention

[0008] Problems to be solved by the invention

[0009] If a plurality of battery cells (cells) are provided in a battery pack, a voltage imbalance may occur between the cell units. For example, if a control unit is provided only on one of the cell units, the power consumption of the cell units will become different, and a power consumption imbalance may occur between the cell units. Moreover, when the connection terminals of the battery pack and the connection terminals of the electrical device body have poor contact, a voltage imbalance may also occur between the cell units. Moreover, for a user, it is cumbersome to prepare a variety of battery packs when using a plurality of electrical devices, and it is desirable to implement an easy-to-use battery pack that can cope with electrical devices of different voltages by switching the voltage. Furthermore, it is desirable to implement a voltage switching type using a battery pack that can be easily installed on an electrical device, rather than using a power supply device that is separate from the electrical device body as in Patent Document 1.

[0010] The present invention is completed in view of the above background, and an object of the present invention is to adjust the voltage balance between multiple battery cells in a battery pack that can switch the connection status of multiple battery cells. Another object of the present invention is to ensure the voltage balance between multiple battery cells in a battery pack that can switch the output voltage so that it can be shared between electrical devices with different voltages and an electrical device using the battery pack. Another object of the present invention is to detect poor contact with the device-side terminal of the electrical device body in a battery pack that can switch the connection status of multiple battery cells, and if poor contact occurs, it can be notified to the operator. Another object of the present invention is to stop charging or discharging if poor contact with the device-side terminal of the electrical device body occurs.

[0011] Technical means of solving problems

[0012] Representative features of the invention disclosed in the present application are described as follows. According to one embodiment of the present invention, a battery pack is provided, comprising: a first battery cell unit, which is composed of a plurality of battery cells connected in series in units of a plurality; a second battery cell unit, which is composed of a plurality of battery cells connected in series in units of a plurality; a first positive terminal, connected to the positive electrode of the first battery cell unit; a first negative terminal, connected to the negative electrode of the first battery cell unit; a second positive terminal, connected to the positive electrode of the second battery cell unit; a second negative terminal, connected to the negative electrode of the second battery cell unit; a signal terminal; and a microcomputer, in which, in the battery pack, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device-side terminal of the high-voltage electrical device body, the first battery cell unit and the second The battery cells are connected in series. On the other hand, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the low-voltage electrical equipment body, the first battery cell and the second battery cell are connected in parallel. In this way, the connection state of the first battery cell and the second battery cell can be switched. In the case of the parallel connection state, only one of the first battery cell and the second battery cell continues to discharge to the low-voltage electrical equipment body, and when a voltage imbalance occurs between the first battery cell and the second battery cell, the microcomputer is configured to output a signal for stopping the discharge to the low-voltage electrical equipment body through the signal terminal.

[0013] In one embodiment of the present invention, the battery pack also includes: a first protection integrated circuit connected to the first battery cell unit; and a second protection integrated circuit connected to the second battery cell unit; wherein the output from the first protection integrated circuit and the output from the second protection integrated circuit are input to the microcomputer, and the microcomputer outputs the signal to the connected electrical equipment body.

[0014] In one embodiment of the present invention, the battery pack further includes: a protection circuit, which is provided for the first battery cell unit and the second battery cell unit to monitor the voltage of the battery cell, and the microcomputer is connected to the protection circuit to monitor the load state of the battery cell.

[0015] In one embodiment of the present invention, the battery pack further includes a power supply circuit connected to a lower cell located on a ground line side in the series connection state of the first cell and the second cell, and supplying power to the microcomputer.

[0016] In one embodiment of the present invention, when the temperature difference between the first battery cell and the second battery cell reaches a threshold value or when the current difference flowing through the first battery cell and the second battery cell reaches a threshold value or more, the microcomputer outputs a signal for stopping the discharge.

[0017] In one embodiment of the present invention, the battery pack further includes: a first voltage detection circuit connected to the first positive terminal; and a second voltage detection circuit connected to the second positive terminal, wherein the outputs from the first voltage detection circuit and the second voltage detection circuit are input to the microcomputer.

[0018] In one embodiment of the present invention, the microcomputer detects the voltages of the first positive terminal and the second positive terminal using outputs from the first voltage detection circuit and the second voltage detection circuit.

[0019] In one embodiment of the present invention, the battery pack also includes: a system detection circuit for detecting whether the battery pack is installed on the electrical equipment body or an external charging device, and the system detection circuit is used to detect poor contact with the device side terminal of the electrical equipment body on which the battery pack is installed.

[0020] In one embodiment of the present invention, the battery pack further comprises: a connection status detection circuit, which detects whether any of the positive terminal or the negative terminal of the battery pack has poor contact by comparing the negative electrode side potentials of the first battery cell unit and the second battery cell unit.

[0021] In one embodiment of the present invention, the battery pack also includes: a system detection circuit for detecting whether the battery pack is installed on the electrical equipment body or an external charging device, the system detection circuit being used to detect poor contact with the device side terminal of the electrical equipment body on which the battery pack is installed; and a first voltage detection circuit and a second voltage detection circuit for detecting the voltage values ​​of the first battery cell and the second battery cell relative to the low-side grounding wire, wherein the microcomputer uses the outputs of the system detection circuit, the first voltage detection circuit, and the second voltage detection circuit to determine whether there are any battery cells that cannot be charged or discharged due to poor contact between the first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal and the device side terminal.

[0022] In one embodiment of the present invention, the battery pack further includes: a remaining capacity display component for displaying the remaining battery power, wherein the remaining battery power is displayed based on the voltage across the first battery cell unit and one of the second battery cell units, or based on the lowest voltage value among the multiple battery cells.

[0023] According to another embodiment of the present invention, there is provided an electrical device body capable of connecting the battery pack, the electrical device body comprising: the device side terminal; a device side signal terminal connected to the signal terminal; and a load connected to the device side terminal, wherein when the signal is input through the device side signal terminal, the operation of the load is stopped.

[0024] In one embodiment of the present invention, the electrical device body further includes: a switch element, which is arranged in series with the load, and when the signal is input through the device-side signal terminal, the switch element is blocked to stop the operation of the load.

[0025] In one embodiment of the present invention, the electrical device body further includes: a device-side microcomputer that controls the switch element, and the device-side microcomputer is configured to output a blocking signal to block the switch element when the signal is input through the device-side signal terminal.

[0026] According to another embodiment of the present invention, there is provided an electrical device having: a battery pack, and an electrical device body capable of connecting the battery pack, wherein the battery pack includes: a first battery cell unit, which is formed by connecting a plurality of battery cells in series in units of a plurality; a second battery cell unit, which is formed by connecting a plurality of battery cells in series in units of a plurality; a first positive terminal connected to the positive electrode of the first battery cell unit; a first negative terminal connected to the negative electrode of the first battery cell unit; a second positive terminal connected to the positive electrode of the second battery cell unit; a second negative terminal connected to the negative electrode of the second battery cell unit; a signal terminal; and a microcomputer. The electrical device body includes: a plurality of device-side terminals connected to each of the first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal; a device-side signal terminal connected to the signal terminal; and a load connected to the device-side terminal. In the battery pack, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the high-voltage electrical equipment body, the first cell unit and the second cell unit are connected in series. On the other hand, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the low-voltage electrical equipment body, the first cell unit and the second cell unit are connected in parallel. In this way, the connection state of the first cell unit and the second cell unit can be switched. In the case of the parallel connection state, only one of the first cell unit and the second cell unit continues to discharge to the low-voltage electrical equipment body. When a voltage imbalance occurs between the first cell unit and the second cell unit, the microcomputer is configured to output a signal for stopping the discharge to the low-voltage electrical equipment body through the signal terminal, and the low-voltage electrical equipment body is configured to stop the load when the signal is input.

[0027] In one embodiment of the present invention, the battery pack also includes: a first protection integrated circuit connected to the first battery cell unit; and a second protection integrated circuit connected to the second battery cell unit; wherein the output from the first protection integrated circuit and the output from the second protection integrated circuit are input to the microcomputer, and the microcomputer outputs the signal to the connected electrical equipment body.

[0028] In one embodiment of the present invention, the electrical device body further comprises: a switch element arranged in series with the load, and the electrical device body is configured to block the switch element and stop the operation of the load when the signal is input through the device-side signal terminal.

[0029] In one embodiment of the present invention, the electrical device body further includes: a device-side microcomputer for controlling the switch element, wherein the device-side microcomputer is configured to output a blocking signal to block the switch element when the signal is input through the device-side signal terminal.

[0030] Effects of the Invention

[0031] According to the present invention, the contact state between the connection terminal and the device-side terminal can be monitored through the control unit of the battery pack, so once the voltage balance abnormality between multiple battery cells caused by poor contact of the terminal part is detected, charging or discharging can be stopped immediately. Furthermore, since the voltage of the battery cell can be adjusted using the discharge component, the voltage difference between the battery cells can be maintained to be small, thereby realizing a battery pack with long life and high reliability. Moreover, there is no need to rely on a mechanical switch mechanism for switching the output voltage. As long as it is installed on the main body of the electrical equipment, the appropriate output voltage can be automatically obtained, so the battery pack can be shared between electrical equipment with different voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a diagram for explaining how the battery pack of the present invention is mounted on an electric power tool.

[0033] Figure 2 Yes means Figure 1 A perspective view of the shape of the battery pack mounting portion 10 of the electric tool body 1.

[0034] Figure 3 FIG. 1 is a perspective view of a battery pack 100 according to an embodiment of the present invention.

[0035] Figure 4 yes Figure 3 An expanded perspective view of the battery pack 100 is shown.

[0036] Figure 5 It is used for illustration purposes Figure 4 An expanded three-dimensional diagram showing the stacking condition and wiring method of the battery cells with the partition 445.

[0037] Figure 6 Yes means Figure 4 FIG. 1 is a diagram of the single-body shape of the positive terminal pair 162 and 172 and the negative terminal pair 167 and 177 for discharge in the power terminals.

[0038] Figure 7 Yes means Figure 4 Figure 1 shows the single-body shapes of the power terminals 161 and 171, 162 and 172, 167 and 177, Figure 7 (1) is the overall stereogram. Figure 7 (2) is the overall side view. Figure 7(3) in the figure is the overall front view.

[0039] Figure 8 1 is a diagram for explaining the connection between the main body of the electric device and the power terminal of the battery pack 100. Figure 8 (1) represents a connection circuit in a state of being connected to the electric tool body 30 of this embodiment, Figure 8 (2) in the figure shows a connection circuit connected to a conventional electric tool body 1 .

[0040] Fig. 9 (1) is a perspective view of the contact end 50 of the electric tool body 30 of this embodiment. Fig. 9 (2) is a three-dimensional diagram of a single short-circuit bar 59. Fig. 9 (3) is a diagram showing a method of connecting the contact end portion 50 and the power terminal of the battery pack 100 .

[0041] Fig.10 (1) is a perspective view of the contact end 20 of the conventional electric tool body 1. Fig.10 (2) is a diagram showing the connection status between the contact end portion 20 and the power terminal of the battery pack 100.

[0042] Fig.11 2 is a diagram showing the shape of a single body of the signal terminal component 240 of the present embodiment. Fig.11 (1) is a stereoscopic view from the upper left front. Fig.11 (2) is a stereoscopic image viewed from the lower right front.

[0043] Fig.12 1 is a circuit diagram showing a state where the battery pack 100 of the present embodiment is connected to a conventional electric tool body 1 .

[0044] Fig.13 1 is a circuit diagram showing a state where the battery pack 100 of the present embodiment is connected to a conventional electric tool body 1A.

[0045] Fig.14 1 is a circuit diagram of the battery pack 100 of the present embodiment, and shows a state in which the battery pack 100 is connected to a 36V electric power tool body 30 .

[0046] Fig.15 1 is another circuit diagram showing a circuit portion for the control unit 350 to detect a poor contact state, among the circuit configurations within the battery pack 100 .

[0047] Fig.16 This is a flowchart showing the flow of determining whether the connection state of the connection terminal of the battery pack 100 is normal or abnormal by the microcomputer of the control unit 350 .

[0048] Fig.17This is a list showing how the microcomputer of the control unit 350 determines the connection state of the battery pack 100 , how the terminal connection state is determined to be normal or abnormal, and the corresponding actions to the determination results.

[0049] Fig.18 It is a timing chart for further explaining the operation of the battery pack 100 .

[0050] Fig.19 It is a schematic diagram showing an electric tool according to a second embodiment of the present invention.

[0051] Fig. 20 1 is a schematic diagram showing an electric tool 630A according to a modified example of the second embodiment of the present invention.

[0052] Explanation of symbols

[0053] 1. 1A: Power tool body

[0054] 2: Shell

[0055] 3: Handle

[0056] 4: Trigger switch (action switch)

[0057] 5: Motor

[0058] 6: Organization Department

[0059] 8: Front tool holding part

[0060] 9: Front-end tools

[0061] 10: Battery pack installation

[0062] 11a, 11b: Track groove

[0063] 12: Bending part

[0064] 14: Protrusion

[0065] 15: Battery Pack

[0066] 20: Contact end

[0067] 20a: Vertical plane

[0068] 20b: Horizontal plane

[0069] 21: Abutment

[0070] 22: Positive input terminal

[0071] 22a: Terminal part

[0072] 24: T terminal

[0073] 24a: Terminal part

[0074] 25: V terminal

[0075] 25a: Terminal part

[0076] 26: LS terminal

[0077] 26a: Terminal part

[0078] 27: Negative input terminal

[0079] 27a: Terminal part

[0080] 28: LD terminal

[0081] 28a: Terminal part

[0082] 30: Power tool body

[0083] 32: Shell

[0084] 33: Handle

[0085] 34: Action switch

[0086] 35: Motor

[0087] 40: Battery pack installation

[0088] 45: Motor

[0089] 50, 50A: Contact end

[0090] 51: Abutment

[0091] 51b, 51c: concave part

[0092] 52: Positive input terminal

[0093] 52a, 52b: Terminal part

[0094] 52c: Wiring terminal

[0095] 54: T terminal

[0096] 54a: Terminal part

[0097] 54c~56c, 58c: Wiring terminal

[0098] 55: V terminal

[0099] 55a: Terminal part

[0100] 56: LS terminal

[0101] 56a: Terminal part

[0102] 56c: Wiring section

[0103] 57: Negative input terminal

[0104] 57a: Terminal part

[0105] 58: LD terminal

[0106] 58a: Terminal part

[0107] 58c: Wiring section

[0108] 58f: Terminal

[0109] 59: Short circuit bar

[0110] 59a: Connection

[0111] 59b, 59c: Terminal part

[0112] 60: Control Department

[0113] 61: Power circuit

[0114] 62: Battery voltage detection circuit

[0115] 63: Switch state detection circuit

[0116] 64: Current detection circuit

[0117] 65: Input line

[0118] 100: Battery Pack

[0119] 101: Lower shell

[0120] 101a: Front surface wall

[0121] 101b: rear surface wall

[0122] 101c: Right side wall

[0123] 101d: Left side wall

[0124] 102: Fixed rib

[0125] 103a~103d: Screw holes

[0126] 104: Slit (wind window)

[0127] 105: ribs

[0128] 110: Upper shell

[0129] 111: Lower section noodles

[0130] 113: Opening

[0131] 114: Step difference

[0132] 115: Upper Noodles

[0133] 120: Slot group configuration area

[0134] 121~128: Slot

[0135] 131: Blocking Department

[0136] 132: Bump

[0137] 134: Slit (wind window)

[0138] 138a, 138b: Track

[0139] 141: Lock

[0140] 142a, 142b: locking portion

[0141] 146: Upper battery cell

[0142] 146a~146e:Battery cells

[0143] 147: Lower battery cell

[0144] 147a~147e:Battery cells

[0145] 150: Circuit board

[0146] 151: Mounting hole

[0147] 160: Slot group configuration area

[0148] 161: Upper positive terminal

[0149] 162: Upper positive terminal

[0150] 162a, 162b: Arm

[0151] 164: T terminal

[0152] 165: V terminal

[0153] 166: LS terminal

[0154] 167: Upper negative terminal

[0155] 167a, 167b: Arm

[0156] 168: LD terminal

[0157] 171, 172: Lower positive terminal

[0158] 172a, 172b: Arm

[0159] 177: Lower negative terminal

[0160] 177a, 177b: Arm

[0161] 180: Substrate cover

[0162] 185a: Vertical wall

[0163] 240: Signal terminal parts

[0164] 241: Base part

[0165] 242: Bridge Department

[0166] 243: Right side

[0167] 243a: Extension

[0168] 243b: Bending part

[0169] 243c: Cutting department

[0170] 244: Left side

[0171] 245: Base of the arm

[0172] 245b: Grooving

[0173] 246: Base of the arm

[0174] 246b: Grooving

[0175] 249, 250: Feet

[0176] 249a: Cutting Department

[0177] 250a, 250b: step difference part

[0178] 251-254: Arm

[0179] 251d, 253d: Fitting part

[0180] 260: Upper terminal parts

[0181] 261: Base part

[0182] 262: Bridge Department

[0183] 262a: Step difference

[0184] 263: Right side

[0185] 263a: Bending part

[0186] 264: Left side

[0187] 264a: Bending part

[0188] 264b: Dashed Line

[0189] 264c: Enhanced surface

[0190] 264d, 264e: Arrow

[0191] 265, 266: Arm

[0192] 265a, 266a: Flat surface

[0193] 265d, 266d: Fitting part

[0194] 267, 268: Arm

[0195] 280: Lower terminal parts

[0196] 281: Base part

[0197] 282: Bridge Department

[0198] 283: Right side

[0199] 284: Left side

[0200] 284b: Dashed line

[0201] 284c: Resection

[0202] 284d, 284e: Arrow

[0203] 285, 286: Arm

[0204] 291: Incision

[0205] 300: Protection IC

[0206] 301: Ground wire

[0207] 302: Action signal

[0208] 305: Over discharge signal

[0209] 306: Overcharge signal

[0210] 310: Current consumption control component

[0211] 320: Protection IC, overcharge signal

[0212] 321: Power circuit

[0213] 322: Upper cell voltage detection circuit

[0214] 323: Upper cell voltage

[0215] 325: Over discharge signal

[0216] 326: Overcharge signal

[0217] 327: Current detection circuit

[0218] 328: LD terminal voltage detection circuit

[0219] 329: Shunt resistor

[0220] 331: Battery cell temperature detection component

[0221] 332: Lower cell voltage detection circuit

[0222] 333: Lower cell voltage

[0223] 335: Remaining capacity display component

[0224] 341: Discharge prohibition signal

[0225] 342: Connecting wire

[0226] 344: Voltage imbalance detection signal

[0227] 344a-344e, 345a-345e, 346a, 346b, 349a-349i, 411a-411d, 421a-421c, 421e, 431a-431f, 453b, 453d: Arrows

[0228] A345, B346: Connection status signal

[0229] 349: Discharge current

[0230] 350: Control Department

[0231] 400: Connection status detection component

[0232] 410: Upper battery cell discharge component

[0233] 411: Discharge execution signal A

[0234] 420: Lower battery cell discharge component

[0235] 421: Discharge execution signal B

[0236] 430: System detection circuit

[0237] 431: System detection signal

[0238] 435: Discharge stop circuit

[0239] 440: Charging stop circuit

[0240] 441: Charging stop signal

[0241] 453: Charge and discharge prohibition signal

[0242] 445: Partition

[0243] 446: Space

[0244] 447a, 447b: Screw column

[0245] 450~452、455~457:Splice bracket

[0246] 461, 466, 471, 476: Lead-out board

[0247] 461a, 466a, 471a, 476a: Lead-out tabs

[0248] 462~465、472~475:Connection plate

[0249] 462a, 463a: Middle lead-out tab

[0250] 482a, 482b: Insulation sheet

[0251] 494b, 496b~499b: End

[0252] 501-506: Steps 601, 630, 630A: Power tools

[0253] 605, 635: Motor

[0254] 660: Microcomputer

[0255] 665: LED

[0256] 665A: Buzzer parts

[0257] 689: Short Circuit

[0258] A: Reference potential

[0259] b1, b2: arrows

[0260] B: Reference potential, battery pack

[0261] B1: Imaginary line

[0262] B2: Chain Line

[0263] R1: Radius of curvature

[0264] H1: Height

[0265] M31~M33, M41, M51, M52, M54, M60~M66, M81, M82, M85, M86, M91~M96, M101: switch element

[0266] R31~R35, R46, R52, R53, R65~R69, R70~R74, R93, R96, R97, R101, R102, R112, R113: resistor

[0267] R51, R54: fake resistors

[0268] R61~R64, R81~R88, R91: voltage divider resistors

[0269] R92, R94: grounding resistance

[0270] R111: Shunt resistor

[0271] S1: Distance

[0272] T: Fixed time

[0273] TH1: Thermistor

[0274] VbatA, VbatB: positive potential

[0275] VDD1: power supply voltage (reference voltage)

[0276] VDD2: reference voltage DETAILED DESCRIPTION

[0277] Example 1

[0278] The following is an explanation of the embodiments of the present invention based on the accompanying drawings. In the following drawings, the same reference numerals are used for the same parts, and repeated explanations are omitted. In this specification, an electric tool operated by a battery pack is used as an example of an electrical device, and the front, rear, left, and right directions of the main body of the electric tool are set as Figure 2 The directions shown in the figure are based on the installation direction of the battery pack, and the front, back, left, right, and up and down directions when observing a single battery pack are based on the installation direction of the battery pack. Figure 3 In addition, for the sake of convenience, the battery pack installation direction is described based on the situation where the battery pack side is moved without moving the power tool body side.

[0279] Figure 1 This is a diagram for explaining the installation of the battery pack of this embodiment to the electric tool. As an embodiment of the electric device, the electric tool has a battery pack and uses a motor to provide a rotational driving force to drive the front tool or the working device. The electric tool is realized in various types, Figure 1The electric tool bodies 1, 30 shown are both called impact tools. The electric tool bodies 1, 30 are tools that perform tightening operations by applying rotational force or axial impact force to a front end tool such as a bit or socket wrench (not shown). These electric tool bodies 1, 30 include a shell 2, 32 that forms an outer shape and serves as an outer frame, and a handle portion 3, 33 is formed on the shell 2, 32. A trigger-shaped action switch 4, 34 is provided in a part of the handle portion 3, 33 and near where the index finger of the operator touches when holding the handle, and a battery pack mounting portion 10, 40 for mounting the battery pack 15, 100 is formed below the handle portion 3, 33.

[0280] The power tool body 1 is a conventional electrical device that uses a battery pack 15 with a rated voltage of 18V. The battery pack 15 is a conventional battery pack that can be installed in the battery pack mounting portion 10 of an electrical device (power tool body 1) that supports 18V as shown in the combination of arrow a. Inside the battery pack 15, only one group of battery cells formed by connecting five lithium-ion battery cells rated at 3.6V in series is accommodated, or two groups of such battery cells are accommodated and connected in parallel with each other. Here, the so-called "battery cell unit" refers to a plurality of battery cells electrically connected. As an example of a "battery cell unit", it includes a connection body formed by connecting a plurality of battery cells in series, a connection body formed by connecting a plurality of battery cells in parallel, or a connection body formed by connecting a plurality of battery cells in series and in parallel. The voltage of 18V means a relatively low voltage, which is sometimes referred to as a low voltage here. Similarly, the power tool body 1 or the electrical device body with a rated voltage of 18V is sometimes referred to as a low-voltage power tool body or a low-voltage electrical device body, respectively. Likewise, the battery pack 15 having a nominal voltage of 18V is sometimes referred to as a low-voltage battery pack.

[0281] The power tool body 30 is an electrical device body with a rated voltage of 36V. As shown by arrow b1, a battery pack 100 capable of outputting 36V is installed in the battery pack installation portion 40. The voltage of 36V means a relatively high voltage, which is sometimes referred to as a high voltage. Similarly, the power tool body 30 or the electrical device body with a rated voltage of 36V is sometimes referred to as a high-voltage power tool body or a high-voltage electrical device body, respectively. Inside the battery pack 100, two groups of battery cell units are accommodated, each of which is formed by connecting five lithium-ion battery cells rated at 3.6V in series. By changing the connection method of the two groups of battery cell units, it is possible to switch between the two outputs of 18V output and 36V output. In this embodiment, the battery pack 100 is constructed to support dual voltages and can achieve low voltage and high voltage outputs. Therefore, the battery pack 100 can be installed on the power tool body 1 supporting 18V as shown by arrow b2, and can also be installed on the power tool body 30 supporting 36V as shown by arrow b1. In this way, the battery pack 100 that can achieve low voltage and high voltage output is sometimes referred to as a voltage variable battery pack. In order to install the battery pack 100 on the power tool bodies 1 and 30 of different voltages as shown by arrows b1 and b2, it is important to: set the shapes of the rail parts or terminal parts of the battery pack mounting parts 10 and 40 to be roughly the same; and be able to switch the output voltage of the battery pack 100. At this time, it is important that the output voltage of the battery pack 100 corresponds to the rated voltage of the installed electrical equipment body or power tool body to avoid voltage setting errors (miss).

[0282] Figure 2: is a three-dimensional diagram showing the shape of the battery pack mounting portion 10 of the power tool body 1. The power tool body 1 shown here is an impact screwdriver, and is provided with a handle portion extending downward from the main body portion of the housing 2, and a battery pack mounting portion 10 is formed on the lower side of the handle portion. A trigger switch 4 is provided on the handle portion. On the front side of the housing 2, an anvil (not shown) is provided as an output shaft, and at the front end of the anvil, a front end tool holding portion 8 for mounting a front end tool 9 is provided. Here, a cross-shaped screwdriver head is installed as the front end tool 9. Not limited to power tools, in all electrical equipment using battery packs, a battery pack mounting portion 10 corresponding to the shape of the installed battery pack is formed so that a battery pack that is not suitable for the battery pack mounting portion 10 cannot be installed. In the battery pack mounting portion 10, rail grooves 11a and 11b extending parallel to the front-to-back direction are formed on the inner wall portions on the left and right sides, and a contact end 20 is provided between them. The contact end 20 is made by integrally molding a non-conductive material such as synthetic resin, and a plurality of metal terminals such as a positive input terminal 22, a negative input terminal 27, and an LD terminal (abnormal signal terminal) 28 are cast therein. The contact end 20 is formed with a vertical surface 20a which becomes a contact surface in the installation direction (front-back direction) and a horizontal surface 20b. The horizontal surface 20b becomes a contact surface with the upper surface 115 (which will be used as the contact surface) when the battery pack 100 is installed. Figure 3 On the front side of the horizontal plane 20b, a raised portion 132 (which will be referred to as Figure 3 The curved portion 12 abuts against the battery pack 100 (described later), and a protrusion 14 is formed near the left and right center of the curved portion 12. The protrusion 14 also serves as a screw column (boss) for screwing the housing of the power tool body 1 divided into two in the left and right directions, and also plays the role of a blocking portion for limiting the relative movement of the battery pack 100 in the installation direction.

[0283] Figure 3 1 is a perspective view of a battery pack 100 according to an embodiment of the present invention. The battery pack 100 can be mounted on the battery pack mounting portion 10, 40 (see Figure 1 ) and automatically switches between low voltage (here 18V) and high voltage (here 36V) outputs according to the shape of the contact terminal on the power tool body 1 or 30. In addition, in order to be compatible with the conventional battery pack 15 (see Figure 1) has installation compatibility, and the shape of the installation part of the battery pack 100 is set to be the same as that of the conventional battery pack 15. The frame of the battery pack 100 is formed by a lower shell 101 and an upper shell 110 that can be divided in the up and down direction. The lower shell 101 and the upper shell 110 are made of a non-electrical member such as a synthetic resin, and are fixed to each other by four screws not shown. The upper shell 110 is formed into a mounting mechanism with two rails 138a and 138b for installation on the battery pack mounting part 10. The rails 138a and 138b are formed in a manner that the long side direction becomes parallel to the installation direction of the battery pack 100, and protrudes in the left and right directions from the left and right side surfaces of the upper shell 110. The front side ends of the rails 138a and 138b become open ends, and the rear side ends become closed ends connected to the front side wall surface of the raised portion 132. The rails 138a and 138b are formed to be aligned with the rail grooves 11a and 11b formed in the battery pack mounting portion 10 of the electric tool body 1 (see Figure 2 ) corresponding to the shape, when the rails 138a, 138b are engaged with the rail grooves 11a, 11b, the locking portion 142a (the locking portion on the right side) which becomes the locking claw is used. Figure 3 ), 142b are locked, thereby fixing the battery pack 100 to the power tool body 1, 30. When the battery pack 100 is removed from the power tool body 1, 30, the lock parts 141 located on the left and right sides are pressed, thereby the locking parts 142a, 142b move to the inside and the locking state is released. Therefore, in this state, the battery pack 100 is moved to the side opposite to the installation direction.

[0284] A flat lower surface 111 is formed on the front side of the upper shell 110, and an upper surface 115 that is higher than the lower surface 111 is formed near the center. The lower surface 111 and the upper surface 115 are formed in a stepped shape, and the connecting portion between them is a step portion 114 that forms a vertical plane. The step portion 114 to the front side portion of the upper surface 115 forms a slot group configuration area 120. In the slot group configuration area 120, a plurality of slots 121 to 128 are formed that extend from the front step portion 114 toward the rear side. The slots 121 to 128 are portions that are cut out in a manner having a specified length along the battery pack installation direction, and a plurality of connection terminals (which will be used as connectors) that can be engaged with the device-side terminals of the power tool body 1, 30 or an external charging device (not shown) are arranged inside the cut portion. Figure 4To be described later). The narrow grooves 121 to 128 are formed with cuts on the upper surface and the vertical plane parallel to the installation direction in such a way that the contact end of the power tool body can be inserted from the lower section surface 111 side. In addition, an opening portion 113 that is continuously opened in the horizontal direction is formed on the lower side of the narrow grooves 121 to 128 and between the lower section surface 111. The opening portion 113 is formed in a planar shape on the left and right sides of a rib-shaped vertical wall portion 185a extending in the vertical direction arranged in the center, and the planar portion is formed by the substrate cover 180. The substrate cover 180 is a part manufactured separately from the upper shell 110.

[0285] Among the slots 121 to 128, the slot 121 near the right rail 138a side of the battery pack 100 becomes the insertion port for the positive terminal (C+ terminal) for charging, and the slot 122 becomes the insertion port for the positive terminal (+ terminal) for discharging. Moreover, the slot 127 near the left rail 138b side of the battery pack 100 becomes the insertion port for the negative terminal (- terminal). In the battery pack 100, the positive side and the negative side of the power terminal for transmitting power are usually arranged in a manner that is sufficiently separated. Therefore, when viewed from the vertical imaginary plane located at the center of the left and right, the positive terminal is provided at a sufficiently separated position on the right side, and the negative terminal is provided at a sufficiently separated position on the left side. Between the positive terminal and the negative terminal, a plurality of signal terminals for signal transmission for controlling the battery pack 100 and the power tool body 1, 30 or an external charging device (not shown) are arranged. Here, four slots 123 to 126 for the signal terminals are provided between the power terminal groups. Slot 123 is a spare terminal insertion port, and no terminal is provided in this embodiment. Slot 124 is an insertion port for the T terminal, which is used to output a signal serving as identification information of the battery pack 100 to the power tool body or the charging device. Slot 125 is an insertion port for the V terminal, which is used to input a control signal from an external charging device (not shown). Slot 126 is an insertion port for the LS terminal, which is used to output battery temperature information. The battery temperature information is obtained by a thermistor (temperature sensing element) not shown in the figure that is provided in contact with the battery cell. On the left side of slot 127, which serves as an insertion port for the negative terminal (-terminal), there is further provided a slot 128 for the LD terminal, which outputs an abnormal stop signal. The abnormal stop signal is output by a battery protection circuit described later contained in the battery pack 100.

[0286] A raised portion 132 is formed on the rear side of the upper surface 115. The raised portion 132 is shaped to be raised upward from the upper surface 115, and a concave stopper 131 is formed near the center thereof. The stopper 131 becomes the protrusion 14 (see FIG. 1 ) when the battery pack 100 is mounted on the battery pack mounting portion 10. Figure 2), so when the protrusion 14 on the side of the power tool body 1 is inserted until it abuts against the blocking portion 131, the multiple terminals (device-side terminals) provided on the power tool body 1 and the multiple connection terminals (to be connected with the battery pack 100) provided on the battery pack 100 are connected. Figure 4 The battery pack 100 is in a conductive state when the locking portion 142a (the locking portion on the right side) of the locking portion 141 is in contact with the battery pack 100. Figure 3 ), 142b are ejected to the left and right directions at the lower part of the rails 138a and 138b by the action of the spring, and engage with the unillustrated recessed parts of the rail grooves 11a and 11b formed in the power tool body 1, thereby preventing the battery pack 100 from falling off. On the inner side of the blocking part 131, there is a slit 134 as a cooling air inlet connected to the inside of the battery pack 100. Moreover, when the battery pack 100 is installed in the power tool body 1, the slit 134 is covered in a manner that cannot be seen from the outside and becomes a closed state. The slit 134 is a wind window for forcing cooling air to flow into the battery pack 100 when the battery pack 100 is connected to a charging device not shown in the figure for charging. The cooling air introduced into the battery pack 100 is discharged to the outside from the slit 104 as an exhaust wind window provided on the front wall of the lower shell 101.

[0287] Figure 4 yes Figure 3 The unfolded stereoscopic view of the battery pack 100. The frame of the battery pack 100 is formed by an upper shell 110 and a lower shell 101 that can be separated in the upper and lower directions. Ten battery cells are accommodated in the internal space of the lower shell 101. Two screw holes 103a and 103b are formed on the front side wall surface of the lower shell 101 for screwing with the upper shell 110. The screws not shown in the figure pass through the screw holes 103a and 103b from the bottom to the top. Two screw holes 103c (not visible in the figure) and 103d are also formed on the rear side wall surface of the lower shell 101. A plurality of battery cells (not shown) are stacked in two sections of five each and fixed by a separator 445 made of a non-conductor such as synthetic resin. The separator 145 holds the plurality of battery cells in a manner that only the left and right sides that become the two ends of the battery cells are open.

[0288] A circuit substrate 150 is fixed on the upper side of the partition 445. The circuit substrate 150 fixes a plurality of connection terminals 161, 162, 164 to 168, 171, 172, and 177 by welding, and electrically connects these connection terminals to a circuit pattern not shown in the figure. The circuit substrate 150 is further equipped with various electronic components (not shown here) such as a battery protection integrated circuit (IC) or a microcomputer, a positive temperature coefficient (PTC) thermistor, a resistor, a capacitor, a fuse, and a light-emitting diode. The material of the circuit substrate 150 is what is called a printed circuit board, that is, a substrate impregnated with a resin that is insulating relative to the raw material, and pattern wiring is printed using a conductor such as copper foil. A single-layer substrate, a double-sided substrate, or a multi-layer substrate can be used. In the present embodiment, a double-sided substrate is used, and the upper surface (the surface and from the top) of the circuit substrate 150 is provided with a printed circuit board. Figure 4 A wiring pattern is formed on the upper surface (the upper surface seen) and the lower surface (the back surface). A slot group configuration area 160 is provided slightly in front of the center in the front-to-back direction of the circuit substrate 150, in which a plurality of connection terminals 161, 162, 164 to 168, 171, 172, 177) are arranged and fixed in the horizontal direction.

[0289] The positive terminals 161, 162, 171, 172 and the negative terminals 167, 177 are arranged at far-apart locations in the left-right direction, and three signal terminals (T terminal 164, V terminal 165, LS terminal 166) are arranged between them. In this embodiment, as a part for power terminals, a set of arms extending in the horizontal direction is used, one set is arranged on the left and right sides of the upper side, and one set is arranged on the left and right sides of the lower side. The detailed shape will be described in detail. Fig.11 In addition, for the signal terminals 164 to 166, 168, the conventional signal terminal parts with one arm in the vertical direction can be used directly. However, in this embodiment, in order to make the positive terminals 161, 162, 171, 172 and the negative terminals 167, 177 have the same fitting state as the device side terminals, a signal terminal part with two arms in the vertical direction is also used on the signal terminal side (the Fig.11 to be described later).

[0290] On the left side of the negative terminal pair 167, 177, an LD terminal 168 is provided. The LD terminal 168 is also formed in a manner having two sets of arms on the upper side and the lower side. All signal terminals 164 to 166, 168 have their respective legs extending from the surface through the plurality of mounting holes 151 formed on the circuit substrate 150 to the back side, and are fixed by welding on the back side. In this embodiment, the fixing method of the three signal terminals 164 to 166 is also characteristic, but the details will be described in detail. Fig.11 and Fig.12 As described above, electronic components (not shown) are mounted on the circuit substrate 150, a plurality of connection terminals are fixed by welding, and then the substrate cover 180 is provided, and the surface of the circuit substrate 150 is reinforced with resin and then fixed to the partition 445 by screws (not shown). Figure 4 The substrate cover 180 is omitted in the figure.

[0291] The lower case 101 is a generally rectangular parallelepiped shape with an open upper surface, and includes a bottom surface, a front surface wall 101a extending in a vertical direction relative to the bottom surface, a rear surface wall 101b, a right side wall 101c, and a left side wall 101d. The internal space of the lower case 101 is set to a shape suitable for accommodating the partition 445. In order to stably hold the partition 445, a plurality of fixing ribs 102 formed on the inner side of the bottom surface or a plurality of ribs 105 formed in a continuous manner in a vertical direction to strengthen the wall surface are formed. A slit 104 is provided in the approximate center of the front surface wall 101a. The slit 134 of the upper case 110 is used as an inlet for allowing cooling air sent from the charging device side to the internal space of the battery pack 100 to flow in when charging is performed using the charging device, and the slit 104 of the lower case 101 is used as an outlet for the cooling air.

[0292] The output from the battery cell side is connected to the circuit substrate 150 via the lead-out tabs 461a, 466a, 471a, 476a extending upward in a plate-like manner. In addition, the ends 494b, 496b to 499b of the wires from the intermediate connection points of the battery cells connected in series are arranged to extend upward and are welded to the circuit substrate. Furthermore, the intermediate lead-out tabs 462a, 463a from the intermediate connection points of the battery cells connected in series are arranged to extend upward in order to connect to the circuit substrate 150. On the upper side of the partition 445, screw columns 447a, 447b for fixing the circuit substrate 150 are formed.

[0293] Next, use Figure 5 The stacking state and wiring method of the battery cells using the partition plate 445 are explained with reference to the expanded perspective view of FIG. The partition plate 445 stacks five of each of the ten battery cells 146a to 146e and 147a to 147e into two upper and lower stages. Figure 54 shows the state where the battery cells 146a to 146e and 147a to 147e are led out from the partition 445, but during assembly, they are inserted into the cylindrical space 446 of the partition 445, and the terminals exposed to the left and right sides of the partition are connected to each other through the connecting plates 462 to 465 and 472 to 475, and the lead plates 461, 466, 471 and 476 are connected to the battery cells. Subsequently, for insulation, the insulating sheets 482a and 482b are attached to the connecting plates 462 to 465 and 472 to 475 or the lead plates 461, 466, 471 and 476.

[0294] The axes of the battery cells are stacked in parallel, and the directions of the adjacent cells are arranged in an alternating manner, and the positive terminals and negative terminals of the adjacent battery cells are connected using metal connecting plates 462-465, 472-475. The terminals on both sides of the battery cells and the connecting plates 462-465, 472-475 are fixed by multiple spot welding. Here, the upper cell unit 146 is formed by five battery cells connected in series in the upper section (with the upper cell unit 146 connected in series). Figure 8 The lower side battery cell unit 147 is formed by five battery cells connected in series on the lower side (described later). Figure 8 (described later). In addition, the upper side and lower side of the battery cell mentioned here do not refer to the physical position of the battery cell in the upper section or the lower section in the lower shell 101, but when two battery cells are connected in series, the battery cell located on the ground line side is called the "lower battery cell", and the battery cell located on the high voltage side when connected in series is called the "upper battery cell", which is based on the electrical potential. In the battery pack of this embodiment, the upper battery cell 146 is arranged in the upper section, and the lower battery cell 147 is arranged in the lower section, but it is not limited to this configuration, and the battery cell configuration method can also be divided into the front side and the rear side instead of the upper section and the lower section.

[0295] Battery cells 146a to 146e, 147a to 147e use lithium-ion battery cells (not shown) with a diameter of 18 mm and a length of 65 mm, which are called 18650 size and can be charged and discharged multiple times. In this embodiment, in order to switch the output voltage from the battery pack 100, an embodiment of a series connection voltage (high voltage side output) and a parallel connection voltage (low voltage side output) of multiple battery cells can be selected. Therefore, according to the concept of the present invention, as long as the number of batteries connected in series in each battery cell is equal, the number of battery cells can be arbitrary. The battery cells used are not limited to the 18650 size, but can also be battery cells of the so-called 21700 size or battery cells of other sizes. Moreover, the shape of the battery cell is not limited to the cylindrical shape, but can also be a rectangular parallelepiped, a laminated shape, or other shapes. The type of battery cell is not limited to lithium-ion batteries, and any type of secondary battery such as nickel-hydrogen battery cells, lithium-ion polymer battery cells, and nickel-cadmium battery cells can also be used. Two electrodes are provided at both ends of the battery cell in the longitudinal direction. One of the two electrodes is a positive electrode and the other is a negative electrode, but the location of the electrodes is not limited to the two ends, and any electrode configuration can be used as long as the battery cell unit can be easily formed in the battery pack.

[0296] The positive electrode of the upper cell unit 146 is connected to the circuit substrate 150 using a lead plate 461 having a lead tab 461a, and the negative electrode of the upper cell unit 146 is connected to the circuit substrate 150 using a lead plate 466 having a lead tab 466a. Similarly, the positive electrode of the lower cell unit 147 is connected to the circuit substrate 150 using a lead plate 471 having a lead tab 471a, and the negative electrode of the lower cell unit 147 is connected to the circuit substrate 150 using a lead plate 476 having a lead tab 476a. Tab holders 450 to 452, 455 to 457 are formed on the upper surface of the partition plate 445, and the tab holders 450 to 452, 455 to 457 are used to hold the tabs of the lead plates 461, 466, 471, 476 in the shape of bent metal sheets. The tab holders 450-452, 455-457 are tab holders formed to hold the lead tabs 461a, 462a, 463a, 466a, 471a, 476a bent into an L-shape, and are integrally formed as recesses having a support surface, a back surface, and both side surfaces when the partition 445 is formed, and the lead tabs 461a, 462a, 463a, 466a, 471a, 476a are respectively embedded in the recesses. Two screw posts 447a, 447b for screwing the circuit substrate 150 are formed on the upper portion of the partition 445. The right sides of the lead plates 461, 471 and the connection plates 463, 465, 473, 475 are covered with an insulating sheet 482a, and the left sides of the lead plates 466, 476 and the connection plates 462, 464, 472, 474 are covered with an insulating sheet 482b. The insulating sheet 482a is made of a non-conductive material, and a sealing material is applied to the inner side thereof.

[0297] Next, use Figure 6 To illustrate the shapes of the two sets of power terminals. Figure 6 yes Figure 4The partial view of the circuit substrate 150 shown only illustrates the positive terminal pair (upper positive terminal 162 and lower positive terminal 172) and the negative terminal pair (upper negative terminal 167 and lower negative terminal 177) fixed to the circuit substrate 150. The positive terminal for output is configured so that the electrically independent upper positive terminal 162 and lower positive terminal 172 are arranged in the front-to-back direction when viewed from the installation position of the circuit substrate 150. They are a plurality of terminals 162 and 172 arranged close to each other, and function as a switching terminal group for voltage switching. The upper positive terminal 162 and the lower positive terminal 172 each have an arm group (arms 162a and 162b, arms 172a and 172b) extending toward the front side. Here, the arms 162a, 162b and the arms 172a, 172b are located at positions separated in the up-down direction, and are shaped so that the front-to-back positions of their fitting parts are roughly the same. These positive terminal pairs 162, 172 are arranged in a single slot 122. The negative terminal pair also has the same shape as the positive terminal pair, and includes an upper negative terminal 167 and a lower negative terminal 177, and these negative terminal pairs 167, 177 are arranged inside a single slot 127. They are multiple terminals 167, 177 arranged close to each other, and function as a switching terminal group for voltage switching. Inside the slot 127, an arm group of the upper negative terminal 167 is arranged on the upper side, and an arm group of the lower negative terminal 177 is arranged on the lower side of the arm group of the upper negative terminal 167. In addition, although Figure 6 Although not shown in the figure, a pair of positive terminals for charging (upper positive terminal 161 and lower positive terminal 171, see Figure 4 ). The shape of the pair of positive terminals 161 and 171 for charging is the same as that of the upper positive terminal 162 and the lower positive terminal 172 .

[0298] Figure 7(1) is a three-dimensional view showing the upper terminal part 260 and the lower terminal part 280 as a single part. The upper terminal part 260 is a common part used as the upper positive terminal 161, 162 and the upper negative terminal 167, and the lower terminal part 280 is a common part used as the lower positive terminal 171, 172 and the lower negative terminal 177. The upper terminal part 260 and the lower terminal part 280 are formed by cutting a flat plate containing a conductive metal by stamping and bending it into a U shape. The upper terminal part 260 is bent in such a way that the bridge part 262, which is the bottom surface of the U shape, is on the rear side, and the lower terminal part 280 is bent in such a way that the bridge part 262 is on the rear side. In the upper terminal part 260, long arms 265, 266 extending toward the upper side of the lower terminal part 280 are formed. When viewed from the front-rear direction in which the arm portions 265 and 266 extend, the bridge portion 262 has a perpendicular surface, and this surface serves as a vertical surface extending in the vertical direction.

[0299] The upper terminal part 260 has a right side surface 263 and a left side surface 264 formed in a manner that is bent into a U-shape and becomes parallel, and a bridge portion 262 that connects them and becomes the rear. On the front side of the right side surface 263 and the left side surface 264, arm portions 265 and 266 are provided from the left and right sides to the inside to clamp the device side terminal. The arm portions 265 and 266 are formed in the following manner: from the lower side of the front edge portion of the left side surface 264 to the position near the upper end, the arm portions 265 and 266 are formed in a manner that extends in a plane in the vertical direction, and from the vicinity of the upper end, the arm portions 265 and 266 are formed in a manner that extends toward the front side. The shape of the right side surface 263 is formed to be symmetrical with the left side surface 264. The arm portion 265 is configured to extend from the upper front edge of the right side surface 263 to the front side, and the arm portion 266 is configured to extend from the upper front edge of the left side surface 264 to the front side. Thus, the arm portions 265 and 266 are formed so as to extend from the upper portion of the front side edge of the base portion 261 toward the front side, that is, in a direction parallel to the installation direction of the battery pack 100. The arm portions 265 and 266 face each other when viewed in the left-right direction, and are stamped to be close to the minimum interval portion, that is, the position where the fitting portion that fits with the device connection terminal is almost in contact, thereby having elasticity. Here, the so-called stamping process refers to plastic processing performed using a stamping machine, in which a raw material such as a metal plate is pressed into a mold using high pressure, and shearing processes such as cutting, punching, and opening are performed, and then bending or drawing processes are performed as needed, thereby shearing and forming into a desired shape. In this embodiment, the upper terminal part 260 and the lower terminal part 280 are formed, for example, by a flat plate with a thickness of 0.8 mm. As a result, the upper positive terminals 161 and 162 and the upper negative terminal 167 have high mechanical strength, and the fitting pressure when fitting with the device side terminal becomes high. Furthermore, heat treatment or plating treatment may be performed after the press working.

[0300] The lower terminal part 280 is also manufactured in the same manner, and has a base part 281, which includes a right side surface 283 and a left side surface 284 formed in a manner of being bent into a U-shape and becoming parallel, and a bridge part 262 connecting them, and arms 285 and 286 are formed from the vicinity of the elongated upper parts of the right side surface 283 and the left side surface 284 toward the front side. The arms 285 and 286 are formed in a shape that clamps the device-side terminal from the left and right sides toward the inside. The distance S between the upper end position of the upper arm group 265 and 266 and the lower end position of the lower arm group 285 and 286 is configured to be approximately the same as the width of the power terminal provided in the conventional 18V battery pack. On the other hand, the upper arm group 265 and 266 and the lower arm group 285 and 286 are respectively arranged in a manner of being separated by a predetermined distance S1 in the upper and lower directions. A notch 291 is formed below the lower arm group 285, 286. The rear side of the lower terminal part 280 is arranged and fixed in the front-to-back direction with a predetermined gap from the right side 263 and the left side 264 of the upper terminal part 260 without contacting each other.

[0301] Figure 7 In (2), the portions of the legs 267 and 268 are hatched to clearly illustrate their range. The base portion 261 referred to in this specification refers to the portion exposed from the surface of the mounted circuit substrate 150 to the upper side, and refers to the portion excluding the arms 265 and 266. The base portion 261 of the upper terminal part 260 includes a right side surface 263, a left side surface 264, and a bridge portion 262. The legs 267 and 268 are connected to the lower side of the base portion 261. The right side surface 263 and the left side surface 264 are substantially rectangular and extend in the vertical direction. In the portion near the upper end, the arms 265 and 266 are formed so as to extend toward the front side. The width (length in the vertical direction) is large near the rear side root of the arms 265 and 266, that is, near the chain line B2, and the width gradually decreases as it moves toward the front. The width becomes constant on the side further forward than the imaginary line B1. The fitting parts 265d and 266d are curved inwardly with a predetermined curvature radius R1 when viewed from above. The arms 265 and 266 are formed to extend forward from the upper front edge of the U-shaped base part, and are formed to have elasticity when not in contact with each other.

[0302] The legs 267 and 268 are inserted into the mounting holes (through holes) of the circuit substrate 150, so that the legs 267 and 268 protrude from the mounting surface (surface) of the circuit substrate 150 to the surface (back side) opposite to the mounting surface, and the legs 267 and 268 are welded to the circuit substrate 150 on the back side. Moreover, the arms 265 and 266 are electrically connected to the battery cells or electronic components mounted on the circuit substrate 150 by welding. Here, the height H1 of the legs 267 and 268 is formed to be greater than the thickness of the circuit substrate 150 but less than twice. At the lower side portion of the rear side of the right side surface 263 and the left side surface 264, as shown by the arrow 262a, the bridge portion 262 protrudes in a manner bent toward the rear side, so that the protruding portion is used for positioning the upper terminal part 260 and the lower terminal part 280 in the upper and lower directions when they are mounted on the circuit substrate 150. A portion extending convexly in the horizontal direction is formed on the front side of the lower part of the right side surface 263 and the left side surface 264, and the convex part forms a bent portion 263a (not visible in the figure) and 264a that bends inward. A substantially circular cutout portion is formed on the upper and lower sides of the bent portion of the bent portion 263a and 264a to facilitate the bending process. The bent portion 263a and 264a and the step portion 262a are formed to contact the upper surface near the mounting hole of the circuit substrate 150 to position the upper terminal part 260 in the vertical direction.

[0303] The base portion 261 is in an inverted L-shape when viewed from the side. The rear portion of the arm portions 265 and 266 forms a flat portion 265a and 266a extending from the vicinity of the connection portion on the rear side toward the front to form the right side surface 263 and the left side surface 264 in the same plane. The front end portion of the arm portions 265 and 266 forms a fitting portion 265d and 266d that is curved in a manner extending outward with a large radius of curvature R1. The curved surface portion on the inner side of the fitting portion 265d and 266d contacts the terminal of the power tool body 1 and 30, thereby the upper terminal part 260 is electrically connected to the connection terminal on the side of the power tool body 1 and 30. The inner side of the fitting portion 265d and 266d is set to the following shape, that is, there is a small gap when the battery pack 100 has been removed from the power tool body 1 and 30. The front sides of the fitting parts 265d and 266d are formed so that the intervals thereof rapidly widen toward the front, and guide the terminals on the electric tool bodies 1 and 30 sides.

[0304] The lower terminal part 280 has a right side surface 283 and a left side surface 284 formed in a manner of being bent into a U-shape and becoming parallel, and a bridge part 282 connecting them, and arms 285 and 286 are provided from the elongated upper parts of the right side surface 283 and the left side surface 284 so as to extend forward and obliquely upward. The width of the arms 285 and 286 in the vertical direction is substantially constant in the front-back direction, and is formed in a manner of extending in the horizontal direction on the front side of the imaginary line B1, but is arranged obliquely on the rear side of the imaginary line B1. A notch 291 is formed below the arm group 285 and 286 of the lower terminal part 280, which is cut out from the front side. As a result of this formation, the length of the arms 265 and 266 of the upper terminal part 260 (length in the front-back direction and forward of B2) is longer than the length of the arms 285 and 286 of the lower terminal part 280 (length in the front-back direction and forward of the arrow 291 position). For such an arm group with different lengths in the front-to-back direction, it is also preferred to make the mating pressure of the mating portion of the upper terminal part 260 the same as the mating pressure of the lower terminal part 280. This is because, if the mating pressure is not made equal, the contact resistance with the flat device-side terminal on the side of the power tool body 1, 30 will change, which may cause slight differences in heat generation or different wear conditions due to long-term use. In this variation, in order to achieve a balance between the mating pressures of the upper terminal part 260 and the lower terminal part 280, the initial gap intervals in the non-installed state of the battery pack are made different. That is, when the battery pack 100 is not installed on the power tool body 1 or 30 (disassembled state), the minimum spacing between the left and right arm parts 265, 266 is different from the spacing between the arm parts 285, 286. Here, the interval between the arm portions 265 and 266 of the upper terminal fitting 260 is 0.2 mm, whereas the minimum interval between the arm portions 285 and 286 of the lower terminal fitting 280 is 0.5 mm.

[0305] In order to make the fitting pressure uniform, the shapes of the upper terminal part 260 and the lower terminal part 280 are also carefully designed. Figure 7As shown in (2), originally, the upper terminal part 260 should have a substantially right-angled inner angle as shown by the dotted line 264b, but here, it is set to the following shape, that is, the outline of the dotted line 264b is extended in the direction of the arrow 264e, and a reinforcing surface 264c is added in the shape of an equilateral triangle when viewed from the side. As a result, the outline of the inner angle portion becomes inclined as shown by the arrow 264d, and the mounting rigidity of the arm portions 265 and 266 of the upper terminal part is improved by the shape change. In accordance with the shape change of the inner angle portion of the upper terminal part 260, the shape of the outer angle portion of the lower terminal part 280 is cut away from the portion of the dotted line 284b in the direction of the arrow 284e, thereby forming a shape with a cut-off portion 284c in the shape of an equilateral triangle when viewed from the side. As a result, the outline of the outer angle portion becomes as shown by the arrow 284d, which reduces the rigidity of the arm portions 285 and 286 of the lower terminal part. The contours of the contour parts indicated by arrows 264d and 284d are determined in the following manner, that is, they are spaced apart by a certain interval in a manner that they are roughly parallel to each other when viewed from the side. In addition, if the cutout portion 284c is formed, the length of the bridge portion 282 in the vertical direction will become shorter. However, since the lower terminal part 280 is small, it is also strong enough compared to the upper terminal part 260, so a balance in strength is achieved by changing their shapes. In this way, for the upper terminal part 260, the shape of the inner corner part is changed by adding a reinforcing surface 264c, and for the lower terminal part 280, the shape of the outer corner part is changed by adjusting the strength by forming the cutout portion 284c, thereby achieving a balance in strength between the two, and the fitting pressure of the arms 265 and 266, 285 and 286 on the main body side terminal can be made roughly the same.

[0306] Figure 7 (3) is a view of the upper terminal part 260 and the lower terminal part 280 as viewed from the front. When the battery pack 100 is not installed, the minimum spacing between the upper and lower arm groups is different. That is, the structure is such that the spacing between the lower arms 285 and 286 in the left-right direction is larger than the spacing between the upper arms 265 and 266 in the left-right direction. It is set to be inversely proportional to the length of the arms 265 and 266 and the length of the arms 285 and 286 in the installation direction (front-back direction) arranged vertically. The long arms 265 and 266 face each other with a narrow spacing in the initial state. On the contrary, the short arms 285 and 286 face each other with a wide spacing.

[0307] As described above, the power terminal uses the upper terminal part 260 and the lower terminal part 280 with a plate thickness of 0.8 mm. As for the signal terminal parts, since only a small current flows through them, they can be manufactured using a metal plate with a thickness of about 0.3 mm, just like the previous battery pack 15. In this modified example, the rigidity of the power terminal through which a large current flows is further improved, and the mating condition can be maintained well not only during operation but also after long-term use. In addition, to make the mating pressure of the upper and lower arm groups roughly the same, it is not limited to the gap adjustment of the mating part and the shape change near the installation root, and it can also be achieved through other changes, especially the adjustment of the plate thickness, the material selection of the terminal parts, etc.

[0308] Next, use Figure 8 The shape of the contact end portion 20 on the electric tool body 1 or 30 and the connection state with the connection terminal of the battery pack 100 when the battery pack 100 is mounted on the electric tool body 1 or 30 will be described. Figure 8 (1) in the figure shows the state where the battery pack 100 is installed in the 36V power tool body 30. As mentioned above, ten battery cells are housed inside the battery pack 100, five of which constitute the upper cell unit 146, and the remaining five constitute the lower cell unit 147. The power tool body 30 is engaged with the upper positive terminal 162 and the upper negative terminal 167 to operate the drive unit 35. The drive unit 35 is a load device that supplies power from the battery pack 100, and has a motor 5 (which is shown in FIG. 1 ). Fig.12 At this time, the short-circuit bar provided in the power tool body 30 forms an electrical connection circuit shown by the dotted line 59, so that the upper battery cell 146 and the lower battery cell 147 are connected in series. That is, the negative electrode of the upper battery cell 146 is connected to the positive electrode of the lower battery cell 147, and the positive electrode of the upper battery cell 146 is connected as the positive output of the battery pack 100, and the negative electrode of the lower battery cell 147 is connected as the negative output. In this way, the series output of the upper battery cell 146 and the lower battery cell 147 is output, that is, the rated 36V.

[0309] Figure 8 (2) in FIG. 1 is a diagram showing a state where the battery pack 100 is installed in the 18V power tool body 1. The 18V power tool body 1 is provided with a positive input terminal (which is sized to fit in with the upper positive terminal 162 and the lower positive terminal 172) having a size of Fig.10 Similarly, a negative input terminal (which will be described later) of a size that can be simultaneously fitted with the upper negative terminal 167 and the lower negative terminal 177 is provided. Fig.10To be described later). That is, it becomes a parallel connection state as described below, that is: the positive poles of the upper battery cell 146 and the lower battery cell 147 are connected to each other to become a positive pole output, and the negative poles of the upper battery cell 146 and the lower battery cell 147 are connected to each other to become a negative pole output. As a result, when connected to the power tool body 1, the rated 18V is automatically output. By changing the connection relationship with the switching terminal group 162, 167, 172, 174 for switching the voltage of the battery pack 100 in this way, the output voltage obtained from the battery pack 100 can be switched.

[0310] Fig. 9 middle, Fig. 9 (1) is a perspective view of the contact end 50 of the electric tool body 30 of this embodiment. Fig. 9 (2) is a three-dimensional diagram of a single short-circuit bar 59. Fig. 9 (3) is a diagram showing a method of connecting the contact end 50 and the power terminal of the battery pack 100. At the contact end 50 of the electric tool body 30 rated at 36V, as input terminals for power, a small terminal portion 52a of a positive input terminal 52 for receiving power and a terminal portion 57a ​​of a negative input terminal 57 are formed and arranged on the upper side. During installation, the terminal portion 52a of the positive input terminal 52 is only engaged with the upper positive terminal 162, and the terminal portion 57a ​​of the negative input terminal 57 is only engaged with the upper negative terminal 167. On the other hand, at the contact end of the electric tool body 30, a short-circuit bar 59 (59a~59c) is provided for short-circuiting the lower positive terminal 172 and the lower negative terminal 177. As shown Fig. 9 As shown in (2) in the figure, the short-circuit bar 59 is a short-circuit element including a metal conductive component, and is a component bent into a "コ" shape. A terminal portion 59b is formed on one end side of the connecting portion 59a of the short-circuit bar 59, and is arranged on the lower side of the terminal portion 52a. A terminal portion 59c is formed on the other end side of the connecting portion 59a of the short-circuit bar 59, and the terminal portion 59c is arranged on the lower side of the terminal portion 57a. The terminal portion 59b is engaged with the lower positive terminal 172, and the terminal portion 59c is engaged with the lower negative terminal 177. The short-circuit bar 59 is cast into the synthetic resin base 51 (to be used as a base) together with other device-side terminals such as the positive input terminal 52 or the negative input terminal 57. Figure 7 At this time, the short-circuit bar 59 does not contact the other metal terminals 52, 54 to 58. Moreover, the short-circuit bar 59 is only used to short-circuit the lower positive terminal 172 and the lower negative terminal 177, so there is no need to wire to the control circuit of the power tool body.

[0311] The positive input terminal 52 is formed by a terminal portion 52a, which is a portion that fits into the upper positive terminal 162 and is formed in a flat plate shape, a wiring portion 52c for welding a wire that is connected to the circuit substrate side of the power tool body 30, and a connecting portion that is a portion that connects the terminal portion 52a and the wiring portion 52c and is cast into the synthetic resin base 51. The negative input terminal 57 is also the same as the positive input terminal 52, and the height of the terminal portion 57a ​​is set to be about half or less than half of the height of the other terminal portions 54a to 56a, 58a. The other terminal portions 54a to 56a, 58a are terminals for signal transmission (signal output), and are connected to the control circuit substrate on the power tool body 30 side via the wiring portions 54c to 56c, 58c and wires (not shown). Concave portions 51 b and 51 c for being clamped by the housing are provided on the front and rear sides of the synthetic resin base 51 of the contact end portion 50 .

[0312] Fig. 9 In (3), when the battery pack 100 is installed, when the battery pack 100 is moved relative to the power tool body 30 in the insertion direction, the positive input terminal 52 and the terminal portion 59b pass through the same slot 128 (see Figure 3 ) and inserted into the interior, and respectively fit into the upper positive terminal 162 and the lower positive terminal 172. At this time, the positive input terminal 52 is pressed between the arm portions 162a and 162b of the upper positive terminal 162 in a manner that expands the interlocking portion of the upper positive terminal 162, and the terminal portion 59b of the short-circuit bar 59 is pressed between the arm portions 172a and 172b of the lower positive terminal 172 in a manner that expands. Similarly, the negative input terminal 57 and the terminal portion 59c pass through the same slot 127 (refer to Figure 3 ) and inserted into the interior, and respectively fitted into the upper negative terminal 167 and the lower negative terminal 177. At this time, the terminal portion 57a ​​of the negative input terminal 57 is pressed between the arm portions 167a and 167b of the upper negative terminal 167 in a manner that expands the fitting portion. Furthermore, the terminal portion 59c of the short-circuit bar 59 is pressed in a manner that expands the arm portions 177a and 177b of the lower negative terminal 177.

[0313] The plate thickness of the terminal parts 52a, 57a, 59b, 59c is slightly larger than the initial gap of the fitting parts of each arm part (the gap when the battery pack 100 is not installed), so the prescribed fitting pressure acts on the fitting points of each of the terminal parts 52a, 57a, 59b, 59c with the upper positive terminal 162, the lower positive terminal 172, the upper negative terminal 167, and the lower negative terminal 177. As a result of this connection, the device-side terminals (terminal parts 52a, 57a, 59b, 59c) of the power tool body 30 and the power terminals (upper positive terminal 162, lower positive terminal 172, upper negative terminal 167, lower negative terminal 177) of the battery pack are in good contact with a small contact resistance. Thus, the power tool body 30 has: a third terminal 52a, which is inserted into the single slot 122 and connected only to the first terminal 162 of the first and second terminals 162 and 172; and a fourth terminal 59b, which is inserted into the single slot 122 and connected only to the second terminal 172. When the battery pack 100 is connected to the power tool body 30, in the single slot 121, the first and third terminals 162 and 52a are connected to each other and both become a first potential, and the second and fourth terminals 172 and 59b are connected to each other and both become a second potential different from the first potential. The negative terminal pair 167 and 177 also become the same connection state, so through Fig. 9 The connection embodiment (1) is realized, thereby realizing the output of the series connection of the upper battery cell 146 and the lower battery cell 147, that is, the rated 36V is output from the battery pack 100.

[0314] On the other hand, when the battery pack 100 is installed in the conventional 18V electric tool body 1, Fig.10When the battery pack 100 is installed in the power tool body 1, the terminal portion 22a of the positive input terminal 22 is inserted and pressed in such a way that the opening ends of the upper positive terminal 162 and the lower positive terminal 172 are expanded, and a part of the upper side of the terminal portion 22a of the positive input terminal 22 contacts the upper positive terminal 162, and a part of the lower side contacts the lower positive terminal 172. In this way, by simultaneously inserting the terminal portion 22a into the arm portions 162a, 162b of the upper positive terminal 162 and the arm portions 172a, 172b of the lower positive terminal 172, the two positive terminals 162 and 172 are in a short-circuited state. Similarly, the terminal portion 27a of the negative input terminal 27 is inserted and pressed in such a manner that the opening ends of the upper negative terminal 167 and the lower negative terminal 177 are expanded, and a part of the upper side area of ​​the terminal portion 27a of the negative input terminal 27 contacts the upper negative terminal 167, and a part of the lower side area contacts the lower negative terminal 177. In this way, by simultaneously inserting the terminal portion 27a into the arm portions 167a, 167b of the upper negative terminal 167 and the arm portions 177a, 177b of the lower negative terminal 177, the two negative terminals 167 and 177 are short-circuited, and the output of the parallel connection of the upper battery cell 146 and the lower battery cell 147, that is, the rated 18V, is output to the power tool body 1. The terminal portion 22a of the positive input terminal 22 and the terminal portion 27a of the negative input terminal 27 include a metal plate having a certain thickness. Therefore, it is important that the fitting pressure of the arm portions of the upper positive electrode terminal 162 and the upper negative electrode terminal 167 is equal to the fitting pressure of the arm portions of the lower positive electrode terminal 172 and the lower negative electrode terminal 177 .

[0315] As described above, the battery pack 100 of this embodiment is installed in either the 18V power tool body 1 or the 36V power tool body 30 to automatically switch the output of the battery pack 100, thereby realizing an easy-to-use battery pack 100 that supports multiple voltages. The voltage switching is not performed on the battery pack 100 side, but is automatically performed according to the shape of the contact end on the power tool body 1, 30 side, so there is no risk of voltage setting errors. Moreover, on the battery pack 100 side, there is no need to set a dedicated voltage switching mechanism such as a mechanical switch, so the structure is simple and the possibility of failure is low, so a long-life battery pack can be realized. The short-circuit bar 59 that short-circuits the lower positive terminal 172 and the lower negative terminal 177 can be installed in the same space as the existing contact end 20 of the 18V battery pack, so a voltage switching battery pack can be realized with a size that is compatible with the past. Furthermore, when charging is performed using an external charging device, it can be Fig.10 Since charging is performed by the connection method (2) in the above description, there is no need to prepare a charging device for charging at both high and low voltages.

[0316] When the battery pack 100 is charged using an external charging device (not shown), the battery pack 100 can be charged using the same charging device as the conventional 18V battery pack. Fig.10 The shape is the same as (1) in FIG. 1 , but the positive terminals 162 and 172 for discharge are replaced by the positive terminals 161 and 171 for charge, and the positive terminals 161 and 171 for charge are connected to the positive terminals of the charging device (not shown). The connection condition at this time is also the same as Fig.10 Thus, the upper battery cell 146 and the lower battery cell 147 are connected in parallel and charged using a charging device for 18V. This has the advantage that when charging the battery pack 100 of this embodiment, it is not necessary to prepare a new charging device.

[0317] Next, use Fig.11The shape of the signal terminal part 240, which is a part used in the three terminals 164 to 166, will be described. The signal terminal part 240 is manufactured by stamping a sheet of metal plate, and is formed from a base part 241 in which a thin metal plate is bent so that a bridge part 242 as a bottom part of a U-shape becomes a vertical plane on the rear side, and an arm group (arm base 245, 246) extends toward the front side, and the arm base 245 is formed in a manner of being separated into an upper and lower arm group (arm 251, 253), and the arm base 246 is formed in a manner of being separated into an upper and lower arm group 252, 254 by forming a cutout 246b extending in the horizontal direction. The metal plate used for stamping is a flat plate with a thickness of 0.3 mm, which can be thinner than the plate thickness of 0.5 mm of the upper terminal part 260 and the lower terminal part 280 used for the power terminal. The upper and lower arm groups are formed in the same shape, and the length in the front-to-back direction, the width in the up-down direction, the plate thickness, etc. are the same. The upper arm group (arms 251 and 252) and the lower arm group (arms 253 and 254) are respectively formed with a fitting portion (251d, 253d, etc.), but the shape bent for the fitting portion is also the same up and down, and the left and right arms are in a plane-symmetrical shape. On the other hand, the installation positions of the legs 249 and 250 are arranged in a manner that is greatly staggered in the front-to-back direction. The shape of the lower side portion of the base 241 is different on the left and right, and the shapes of the right side surface 243 and the left side surface 244 are asymmetrical. Compared with the position of the previous leg 250, the leg 249 is arranged to be greatly staggered toward the front side, and the legs 249 and 250 are greatly separated in the front-to-back direction. Thus, the foot 249 and the foot 250 are not arranged adjacent to each other in the left-right direction, but are arranged in a staggered manner, so that an extension portion 243a extending greatly forward is formed near the lower side of the right side surface 243, and the foot 249 is formed in a manner extending downward from its front end portion. The foot 249 and the foot 250 respectively penetrate through the through hole (not shown) formed on the circuit substrate 150 from the surface to the back side, and are fixed to the circuit substrate 150 by welding the portion protruding to the back side, and the upper arm group (arms 251 and 252) and the lower arm group (arms 253 and 254) are electrically connected to the electronic components mounted on the circuit substrate 150.

[0318] A bent portion 243b is formed above the leg portion 249, and the bent portion 243b is used to limit the mounting hole 151 (see Figure 4) is inserted and bent toward the left direction. On the upper and lower sides of the bent portion of the bending portion 243b, cutout portions 243c and 249a that are cut into semicircular shapes are formed to facilitate the bending process. For positioning the foot 250 on the rear side to the circuit substrate 150, step portions 250a and 250b formed on the front and rear sides of the foot 250 are used. The step portion 250a is formed by extending the lower side portion of the left side surface 244 toward the front side, and the step portion 250b is formed by utilizing the lower side portion of the bridge portion 242 that is bent into a U shape. In this way, the step portions 250a and 250b abut against the surface of the circuit substrate 150, thereby determining the installation position of the foot 250 in the up-and-down direction. The installation position of the feet 249 and 250 in the front-to-back direction is determined by the mounting hole 151 (refer to Figure 4 )’s position.

[0319] Fig.11(2) is a diagram of the signal terminal part 240 monomer observed from the lower front side. As can be seen from this figure, a groove 245b extending in the horizontal direction is formed on the front side of the arm base 245, thereby separating it into upper and lower arm groups (arms 251, 253). Moreover, the right foot 249 is configured in a manner that deviates significantly toward the front side than the left foot 250. As a result, even if a force in the upward or downward direction is applied to the four arms 251, 252, 253, 254, the signal terminal part 240 can be firmly held on the circuit substrate. The external force applied to the arms 251, 252, 253, 254 is applied in a manner that pushes the arm group toward the rear side when the battery pack 100 is installed on the power tool body 1, 30. This force is in a direction that causes the signal terminal part 240 to fall toward the rear. On the contrary, when the battery pack 100 is removed from the power tool body 1, 30, a force is applied to push the arm group forward, and this force is applied in a direction that causes the signal terminal part 240 to fall forward. In this way, by staggering the positions of the legs 249, 250 in the front-to-back direction, the external force applied when the battery pack 100 is installed and removed can be effectively blocked, thereby greatly strengthening the installation rigidity of the signal terminal part 240, thereby improving the durability of the battery pack 100. Furthermore, the arm group is also formed in two sections, the upper side and the lower side, so that even if it is subjected to various vibrations or external forces during the operation of the power tool, it can maintain a good contact state with the terminals on the power tool body side through the four contact areas of the arm. The so-called "contact area" here refers to the area where the arm parts 251, 252, 253, and 254 of the signal terminal part 240 contact the input terminals (for example, the positive input terminal 52 and the negative input terminal 57) when the battery pack 100 is installed on the power tool body. On the other hand, the number of mounting holes or the number of welding locations of the circuit board 150 required when manufacturing the signal terminal parts 240 is the same as that in the related art, so that an increase in manufacturing cost can be suppressed.

[0320] The signal terminal part 240 of this embodiment not only improves rigidity, but also has other effects. The conventional signal terminal part (not shown) is provided with two feet that are welded to the circuit substrate and electrically / mechanically mounted, but the feet are arranged in parallel in the left and right directions, and the distance between the feet is narrow, so the welding parts are often connected together, and it is impossible to make the signal pattern pass through the left and right feet. In the battery pack 100 of this embodiment, one of the feet 249 of the signal terminal part 240 is arranged on the front side, and the other foot 250 is located on the rear side, so that the two feet are arranged separately. As a result, the distance between the feet of the signal terminal part 240 becomes wider, so that it is easy to carry out multiple wiring or wiring of a thick pattern through which the main current flows. This signal terminal part 240 is suitable for the battery pack 100 of this embodiment, that is, compared with the conventional battery pack, it is desired to achieve high functionality and promote miniaturization in terms of voltage ratio. In particular, when the voltage is increased and the voltage switching function is realized, the number of electronic components mounted on the circuit substrate 150 increases. Therefore, it is necessary to improve the efficiency of pattern wiring and to make the wiring through which the main current flows thicker. In this embodiment, a larger circuit board 150 than conventionally used boards is used, and electronic components are mounted not only behind the connection terminal group but also in the front area.

[0321] Fig.121 is a circuit diagram showing a state where the battery pack 100 of the present embodiment is connected to a conventional electric tool body 1. The conventional electric tool body 1 is composed of a positive input terminal 22, a negative input terminal 27 and an LD terminal 28 on the device side. A trigger switch 4 and a DC motor 5 are connected between the positive input terminal 22 and the negative input terminal 27. A switching element M101 formed of a semiconductor is provided between the motor 5 and the negative input terminal 27. The drain-source of the switching element M101 is connected to the power supply path of the motor 5, and the gate is connected to the positive input terminal 22 via a resistor R101. Moreover, the gate of the switching element M101 is connected to the LD terminal 28 via a resistor R102. Normally, the LD terminal 28 on the battery pack 100 side is in a high impedance state. At this time, a positive voltage is applied to the gate of the switching element M101 via the resistor R101, and the switching element M101 is in an on state. At this time, if the LD terminal 168 is lowered to the ground potential by the discharge prohibition signal 341 from the battery pack 100 side, the gate potential of the switch element M101 becomes a voltage obtained by dividing the voltage of the positive input terminal 22 by the resistors R101 and R102, and the divided potential becomes a potential that blocks the source-drain of the switch element M101. As a result, the power supply path to the motor 5 is blocked, and the rotation of the motor 5 stops. The potential switching of the LD terminal 168 is performed by the control of the control unit 350 on the battery pack 100 side, and is performed when the voltage of the battery cell drops to a specified value, when the so-called over-discharge state is reached, when the current flowing through the battery cell exceeds a specified upper limit, when the temperature of the battery cell exceeds an upper limit, etc.

[0322] The battery pack 100 is Figure 4 As shown, it is composed of an upper positive terminal (upper +) 162, a lower positive terminal (lower +) 172, an upper negative terminal (upper -) 167 and a lower negative terminal (lower -) 177. In addition, it has an LD terminal 168 as a signal terminal. In the battery pack 100, in addition to these terminals, other signal terminal groups (T terminal 164, V terminal 165, LS terminal 166) are also provided, but their illustrations are omitted here. The output of the upper battery cell unit 146 is connected to the upper positive terminal 162 and the lower negative terminal 177. That is, the positive electrode (+ output) of the upper battery cell unit 146 is connected to the upper positive terminal 162, and the negative electrode (- output) of the upper battery cell unit 146 is connected to the lower negative terminal 177. Likewise, the positive electrode (+ output) of the lower cell unit 147 is connected to the lower positive terminal 172 , and the negative electrode (− output) of the lower cell unit 147 is connected to the upper negative terminal 167 .

[0323] The upper cell unit 146 and the lower cell unit 147 are formed by connecting five lithium-ion battery cells in series. A protection IC 300 is connected to the upper cell unit 146. The protection IC 300 performs the overcharge protection function and the over-discharge protection function by inputting the voltages at both ends of each battery cell of the upper cell unit 146. In addition, it also performs the cell balancing function, the cascade connection function, and the disconnection detection function. The protection IC 300 is an integrated circuit commercially available as a "protection IC for lithium-ion batteries". The protection IC 300 has a built-in power supply circuit, and the power supply circuit obtains the operating power of the protection IC from the voltage of the upper cell unit 146. Moreover, when the voltage of the battery cell of the upper battery cell unit 146 drops to less than a specified value and becomes an over-discharge state, the protection IC300 outputs a signal (high signal) 305 indicating over-discharge to the control unit 350. When the voltage of the battery cell of the upper battery cell unit 146 reaches a specified value or more during charging and becomes an over-charge state, the protection IC300 outputs a signal (high signal) 306 indicating over-charge to the control unit 350.

[0324] The protection IC 326 is connected to the lower cell unit 147. Here, a control unit 350 is also provided in the circuit of the lower cell unit 147, that is, in the circuit between the lower positive terminal 172 and the upper negative terminal 167. That is, the protection circuit arranged in parallel with the upper cell unit 146 includes only the protection IC 300, whereas the protection circuit arranged in parallel with the lower cell unit 147 includes the protection IC 326 and the control unit 350. The control unit 350 includes a microcontroller unit (MCU) (so-called "microcomputer"). The control unit 350 receives inputs of the output from the protection IC 300 (over-discharge signal 305, over-charge signal 306), the output from the protection IC 326 (over-discharge signal 325, over-charge signal 326), and the signal from the cell temperature detection component 331. The microcomputer of the control unit 350 includes a voltage detection circuit called an analog front end (AFE), for example, and measures the current value flowing through the lower battery cell 147 based on the output voltage of the current detection circuit 327. The driving power supply of the control unit 350 is generated by the power supply circuit 321 connected to the lower battery cell 147, and the driving power supply (VDD1) is supplied to the control unit 350.

[0325] A shunt resistor 329 is provided on the grounding line side of the lower battery cell 147, but no shunt resistor is provided on the upper battery cell 146 side. This is because, when the upper battery cell 146 and the lower battery cell 147 are connected in series, the constant current value can be measured using only the shunt resistor 329. On the other hand, when the upper battery cell 146 and the lower battery cell 147 are connected in parallel, the actual measured current value on the upper battery cell 146 side cannot be measured. However, the control unit 350 only needs to monitor the current value of the upper battery cell 146 as if it is equal to that of the lower battery cell 147. In addition, it can also be configured so that a shunt resistor and a voltage detection circuit are provided on the grounding line side of the upper battery cell 146, and the current value on the lower battery cell 147 side is also directly monitored by the microcomputer of the control unit 350.

[0326] The control unit 350 monitors the current value or the cell temperature, and monitors the state of the upper cell unit 146 and the lower cell unit 147 to control the operation of the two in an integrated manner. For example, the control may be performed in the following manner, that is, the temperature of the cell units 146 and 147 is monitored, and if the difference between their temperatures reaches or exceeds a threshold value, it is determined that a poor contact of the connection terminal has occurred, and the control unit 350 stops charging and discharging. Moreover, in the case where an emergency stop of the power tool body 1 is required, the potential of the LD terminal 168 is changed by issuing a discharge prohibition signal 341, so that the power tool body 1 side stops operation via the LD terminal 28. Among these monitorings performed by the control unit 350, the most important is the amount of current flowing through the battery cells contained in the upper cell unit 146 and the lower cell unit 147. In recent power tools, with the improvement of the performance and capacity of the battery cells, a large current can be drawn from the battery pack 100. However, considering the life or heat generation, it is preferable to limit the battery cells to a specified current (below the current upper limit value). Therefore, in order to monitor the current flowing through the battery cells, the control unit 350 uses the shunt resistor 329 and the current detection circuit 327 interposed in the middle of the power supply line of the lower cell unit 147 to monitor the current value.

[0327] Monitoring the current value also helps detect poor contact of the connection terminals 161, 167, 171, and 177 during charging. When the battery pack 100 is connected to an external charging device (not shown) for constant current charging control, the charging current flowing through the upper cell unit 146 and the lower cell unit 147 becomes a specified current value. For example, when a charging current of 12A flows through the charging device, it is ideal that a charging current of 6A flows through each of the upper cell unit 146 and the lower cell unit 147. However, if any of the connection terminals 161, 167, 171, and 177 and the device-side terminals on the charging device side have poor contact, the current flowing in the cell unit connected to the connection terminal having poor contact becomes zero or greatly decreases, and the total current 12A flows to the remaining cell units. Therefore, the microcomputer determines whether the detection value of the current detection circuit 327 is within the normal current range. If it is very small (e.g., close to 0A) or very large (e.g., above 10A), it is determined that any of the connections of the plurality of battery cells is abnormal, and the charging by the charging device is stopped. As described above, even when the battery pack 100 is charged using an external charging device, the control unit 350 determines whether an abnormality has occurred in the connection of the plurality of battery cells based on the charging current. If it is determined that an abnormality has occurred, a charging stop signal is transmitted (output) to the external charging device via the LS terminal 166.

[0328] The protection circuit for managing the lower cell unit 147, including the protection IC 320, the control unit 350, the power supply circuit 321, the current detection circuit 327, etc., can also be integrated into one chip to form a "battery management IC". On the other hand, the protection IC 300 for the upper cell unit 146 can be the same as that in the conventional battery pack 15 (see Figure 1 ) is a protection IC that is commercially available as a “battery protection IC” for five batteries. The operation of the protection IC 320 is substantially the same as that of the protection IC 300. When it is detected that the voltage of the battery cell in the lower battery cell unit 147 drops to a state of a specified lower limit value (over-discharge state), the over-discharge signal 325 is sent to the control unit 350. Furthermore, when the battery pack 100 is installed in an external charging device (not shown) for charging, the protection IC 320 sends an over-charge signal 325 indicating an over-charge state to the control unit 350 when it detects that the voltage of the battery cell exceeds a specified upper limit value. The control unit 350 receives the over-charge signal 325 through the LS terminal 166 (refer to Figure 4 ) to send a charging stop signal to a charging device (not shown). As described above, the upper cell unit 146 and the lower cell unit 147 are each equipped with a protection circuit for the battery cell, so that the cell balancing function can be achieved through extremely precise battery monitoring.

[0329] In this embodiment, the protection circuit of the upper cell unit 146 only has the protection IC 300 without a microcomputer. In contrast, in the protection circuit of the lower cell unit 147, in addition to the protection IC 300, a control unit 350 including a microcomputer is provided. In addition, the power supply circuit 321 generates power for the operation of the control unit 350 using the power of the lower cell unit 147. The battery pack 100 of this embodiment is a voltage switching type between 18V and 36V. When a microcomputer is installed in the protection circuit on the upper cell unit 146 side, the ground potential of the control unit 350 changes when the two cell units are connected in series and in parallel. On the other hand, if the power supply circuit 321 is provided on the lower side, the ground potential of the power supply circuit 321 does not change. Therefore, in this embodiment, the control unit 350 equipped with a microcomputer is not provided in the circuit of the upper cell unit 146, but in the circuit of the lower cell unit 147. With the configuration of the microcomputer, even when the output voltage is switched between the rated 18 V and 36 V, the control unit 350 including the microcomputer can be operated stably.

[0330] The practice of only providing the control unit 350 including the microcomputer in the circuit on one of the battery cells will cause the problem of unbalanced power consumption between the two battery cells. Although the power consumption of the control unit 350 is extremely weak, the power consumption on the lower battery cell 147 side will be greater than the power consumption on the upper battery cell 146 side. The long-term unbalanced state of power consumption will cause the potential on the lower battery cell 147 side to become lower than that on the upper battery cell, which is not good. In particular, when the upper battery cell 146 and the lower battery cell 147 are connected in parallel to output a rated 18V, a circulating current will flow due to the voltage imbalance between the battery cells just after the parallel connection state is achieved. Therefore, in the present embodiment, a consumption current control component 310 is provided in the circuit of the upper battery cell 146 with less power consumption, and the consumption current control component 310 has the function of adjusting the consumption current with the lower battery cell 147. The current consumption control member 310 is connected in parallel with the lower power consumption side of the two cell units, in this case, the upper cell unit 146, and is mounted on the circuit board 150 (see FIG. 1 ) as a load circuit independent of the integrated protection IC 300. Figure 4 )middle.

[0331] The current consumption control unit 310 is controlled to operate in conjunction with the operation of the control unit 350. The microcomputer included in the control unit 350 can switch between holding and releasing the power supply voltage (reference voltage VDD1) applied to itself, and has a normal operation state (normal mode) and an operation stop state (so-called sleep state). While the microcomputer of the control unit 350 holds the reference voltage VDD1, the protection IC 300 is also in an operation state by switching the state of the ground line 301 used as a control signal. In this embodiment, the circuit of the current consumption control unit 310 is carefully designed and configured so that once the microcomputer of the control unit 350 is in a state of holding the reference voltage VDD1, the current for adjusting power consumption is passed through the current consumption control unit 310 in conjunction with the control unit 350, and the current consumption control unit 310 switches the state of the ground line 301. As a result, the protection IC 300 is also activated in conjunction with the activation of the control unit 350. Since the power supply circuit 321 of the control unit 350 is shared with the protection IC 320, when the microcomputer is started, the protection IC 320 is also started at the same time. Through the consumption current control component 310, the consumption current consumed in the battery group (lower battery unit 147) connected to the control unit 350 and the other battery group (upper battery unit 146) becomes the same.

[0332] The current consumption control component 310 is an electrical circuit composed of multiple switching elements M31~M33 such as field effect transistors (FET) and multiple resistors (resistors R31~R35). The basic circuit structure is: a series connection of resistors R31 and R34 as two dummy loads is connected between the two terminals of the battery cell 146, and the conduction or disconnection of this circuit is switched by the switch element M32. The source terminal of the switch element M32 is connected to the positive electrode of the upper battery cell 146, and the drain terminal is connected to the resistor R31. The gate terminal of the switch element M32 is connected to the connection point of the resistors R32 and R35. One end of the resistor R32 is connected to the source terminal of the switch element M32, and the other end is connected to the gate terminal. One end of the resistor R35 is connected to the gate terminal of the switch element M32, and the other end is connected to the drain terminal of the switch element M33. The switch element M33 inputs a gate signal to the power supply voltage (VDD1) of the microcomputer included in the control unit 350, and switches on or off in conjunction with the reference voltage VDD1. The source terminal of the switch element M33 is grounded, and a resistor R33 is connected between the source terminal and the gate terminal. The resistor R33 is configured to stably switch the switch element M33 according to the voltage change of the gate signal. When the reference voltage VDD1 of the microcomputer is disconnected, the gate potential of the switch element M33 is 0V. Thus, the switch element M33 becomes disconnected (closed). When the switch element M33 is in the disconnected state, the switch element M32 is also in the disconnected state, so the current path toward the dummy load side formed by the resistors R31 and R34 is blocked, and therefore, the power consumption of the current consumption control component 310 is zero. In order to make the protection IC300 also disconnected in this state, a switch element M31 is also provided, and the switch element M31 inputs the potential of the connection point of the resistors R31 and R32 as a gate signal (action signal 302). The drain terminal of the switch element M31 is connected to the ground line 301 of the built-in power supply (not shown) of the protection IC300, and the source terminal is connected to the negative electrode of the upper battery cell 146. The action signal 302 is a signal indicating the operating state of the consumption current control component 310. When it is at a low level, it indicates that the consumption current control component 310 is running, that is, the microcomputer of the control unit 350 is also running. On the other hand, when the consumption current control component 310 is not in the operating state, that is, the microcomputer of the control unit 350 is in a stopped state, the action signal 302 becomes low, and the ground line 301 becomes a high impedance state, so the protection IC300 stops.

[0333] The potential (reference potential A) of the negative electrode of the upper cell unit 146 is the ground potential when the upper cell unit 146 and the lower cell unit 147 are connected in parallel, but is equal to the positive potential of the lower cell unit 147 when they are connected in series. In this connection state, the potential of the upper cell unit 146 is not applied to the resistor R31, and the switch element M31 becomes disconnected, so the ground line 301 becomes a high impedance state that is not connected. On the other hand, when the switch element M32 becomes conductive and current flows through the dummy load, the divided voltage of the resistors R31 and R32 flows to the gate terminal of the switch element M31, so the switch element M31 becomes conductive. As a result, the ground line 301 is connected to the reference potential A, and therefore, power is supplied to the built-in power supply in the protection IC 300, so that the protection IC 300 is started. According to the connection embodiment as described above, by consuming the current control component 310, it is possible to consume power corresponding to the power consumption of the microcomputer on the lower cell unit 147 side in the circuit of the upper cell unit 146. Furthermore, the protection IC 300 itself can be activated and deactivated by switching the current consumption control member 310. Therefore, the microcomputer of the control unit 350 can activate or deactivate the protection circuit of the lower cell unit 147 in conjunction with the protection circuit of the upper cell unit 146.

[0334] The microcomputer has three states: normal, sleep, and shutdown. Normal is a state in which the microcomputer is always started. Sleep is a mode in which the microcomputer starts intermittently by itself, repeating the action of stopping for 49 milliseconds after starting for 1 millisecond. Shutdown is a state in which the reference voltage VDD1 is not supplied at all, and is a state in which the microcomputer is completely stopped. The microcomputer operates regardless of whether the battery pack 100 is installed in the power tool body 1 or not. However, when the battery pack 100 is not installed, or when the power tool has not been used for a certain period of time despite being installed, for example, when the trigger operation has not been performed for about two hours after the trigger operation is completed, the microcomputer enters a sleep state. Even in the sleep state, the current consumption control component 310 still operates in conjunction with the startup of the microcomputer, and the protection IC 300 is also started via the current consumption control component 310. When the trigger switch 4 of the electric tool body 1 is pulled and current flows through the motor 5 , the microcomputer of the control unit 350 detects an increase in the current value detected by the current detection circuit 327 and returns to a normal state.

[0335] In the present embodiment, in the case of adopting a structure in which a microcomputer is included in the protection circuit of only one of the multiple battery cells, a consumption current control component 310 for performing power consumption corresponding to the microcomputer is added to the protection circuit of the other battery cells that are not provided with a microcomputer. This solves the problem of the increase in potential difference between the multiple battery cells due to the battery pack being placed in a disassembled state for a long time, thereby adjusting the balance of consumption current of each of the multiple battery cells, thereby realizing a battery pack in which the voltage balance of each battery cell will not deteriorate even after long-term storage.

[0336] The battery pack 100 is provided with a remaining capacity display component 335 for displaying the remaining battery capacity. When a switch (not shown) for displaying the remaining battery capacity is pressed, the battery voltage is displayed by the number of light-emitting diodes (not shown). The remaining battery capacity displayed by the remaining capacity display component 335 can be displayed based on the voltage across one of the upper battery cell 146 and the lower battery cell 147, or can be displayed based on the lowest voltage value among the ten battery cells.

[0337] The control unit 350 is input with the output of the upper cell voltage detection circuit 322 connected to the upper positive terminal 162. This output indicates the potential of the upper cell 146 when the battery pack 100 is not installed on the power tool body 1, 30 or the charging device (not shown). On the other hand, when installed on the power tool body 1 for low voltage (18V), since the upper positive terminal 162 is connected to the lower positive terminal 172, the positive poles of the upper cell 146 and the lower cell 147 are at the same potential, and the negative poles are at the same potential. Accordingly, the microcomputer contained in the control unit 350 can judge whether the battery pack 100 is in an uninstalled state, installed on a low voltage device body, or installed on a high voltage device by comparing the potential of the upper positive terminal 162 with the potential of the lower positive terminal 172. In addition, in order to detect the potential of the lower positive terminal 172, the control unit 350 can be configured to obtain the positive electrode potential of the uppermost battery cell 147a among the battery cells in the lower battery cell unit 147. In this way, the microcomputer provided in the circuit of the lower battery cell unit 147 can determine whether the upper battery cell unit 146 and the lower battery cell unit 147 of the battery pack 100 are in a state of series connection (a state in which they are installed in a 36V device) or in a state of parallel connection (a state in which they are installed in an 18V device). In this way, the microcomputer can also monitor the voltage value on the upper battery cell 146 side that exceeds the power supply voltage acquisition range (the voltage in the lower battery cell unit 147), thereby being able to determine the connection state of the battery pack 100 in a voltage switching mode and to perform optimal control corresponding to the determined connection state.

[0338] The LD terminal 168 is a terminal for transmitting (outputting) the following signals, namely: a signal from the battery pack 100 side to stop the power tool body 1, or a signal to stop the operation of an electrical device that uses the battery pack (not shown) as a power source. In order to change the state of the LD terminal 168, the control unit 350 switches the gate signal (discharge inhibition signal 341) input to the semiconductor switch element M41 from a normal low state ("discharge allowed" from the battery pack 100) to a high state ("discharge prohibited" from the battery pack 100). The switch element M41 is, for example, a P-type field effect transistor (FET), the drain side of which is connected to the LD terminal 168 and the source side is grounded. Therefore, when the switch element M41 is normally in operation (the discharge inhibition signal 341 is low), the LD terminal 28 is in a high impedance state, and the potential of the LD terminal 28 is approximately equal to the voltage of the positive input terminal 22 on the power tool body 1 side. On the other hand, when the discharge prohibition signal 341 is switched to high by the control from the control unit 350, the source-drain of the switch element M41 is connected to the ground by conduction, so the potential of the LD terminal 28 on the side of the power tool body 1 drops to the ground potential. As a result, due to the drop in the gate potential of the switch element M101 on the side of the power tool body 1, that is, the voltage-dividing potential formed by the voltage-dividing resistors R101 and R102, the source-drain of the switch element M101 becomes non-conductive, the power circuit of the power tool body 1 is blocked, and the rotation of the motor 5 is prevented. In this way, the discharge prohibition signal 341 issued by the control unit 350 of the battery pack 100 can prevent the rotation of the motor 5 of the power tool body 1. Therefore, when the control unit 350 has to terminate the power supply from the battery pack 100, for example, when excessive current occurs during discharge, the battery cell voltage drops during discharge (over-discharge), and the battery cell temperature rises abnormally (over-temperature), etc., the operation of the power tool or electrical equipment can be stopped as soon as possible, thereby protecting not only the battery pack 100 but also the power tool body 1.

[0339] Fig.13 1 is a circuit diagram of the battery pack 100 of this embodiment, and is a diagram showing a state where the battery pack 100 is connected to an 18V electric tool body 1A with a body-side microcomputer. Fig.12 The same as shown, only the structure of the power tool body 1A side is different. Fig.12The electric tool body 1 shown does not include a microcomputer. However, in recent electric tools, the use of a control unit 60 having a microcomputer for controlling the motor 5 has gradually increased. The electric tool body 1A includes a power supply circuit 61, and the control unit 60 operates by a fixed low voltage (reference voltage VDD2) generated by the power supply circuit 61. The control unit 60 includes a microcomputer, and the various states in the electric tool body 1A are monitored or controlled by the microcomputer. In this embodiment, a DC motor 35 is provided in the power supply path between the positive input terminal 22 and the negative input terminal 27, and an action switch 34 for starting or stopping the rotation of the motor 35 is provided in this circuit. In addition, a battery voltage detection circuit 62 is provided to measure the voltage applied from the battery pack to the motor 35 and output it to the control unit 60. Furthermore, a switch (SW) state detection circuit 63 is provided, and the switch (SW) state detection circuit 63 detects whether the action switch 34 is in a connected state (conductive state) or in a blocked state (disconnected state), and its signal is output to the control unit 60. A semiconductor switching element M101 and a shunt resistor R111 are inserted between the motor 35 and the negative input terminal 27. The switching element M101 is, for example, a FET (field effect transistor), and its gate signal is sent by the control unit 60. The voltage across the shunt resistor R111 is detected by the current detection circuit 64, and its value is output to the control unit 60. In this circuit diagram, the motor 35 is shown as a brushed DC motor, but a structure using a known inverter circuit to drive a three-phase brushless motor can also be adopted. In this case, the rotation of the motor 35 can be stopped by connecting the switching element M101 in series in the power path input to the inverter circuit not shown, or by controlling the switching element not shown in the inverter circuit by the control unit 60 instead of the switching element M101.

[0340] The LD terminal 28 of the power tool body 1A is connected to the control unit 60 via a resistor R112. On the control unit 60 side of the resistor R112, a reference voltage VDD2 is also connected via a resistor R113. Therefore, when the LD terminal 28 is in a high impedance state, a voltage close to the reference voltage VDD2 is applied to the input line 65 of the control unit 60. When the LD terminal 28 drops to the ground potential, the divided voltage of the resistors R113 and R112, that is, a voltage significantly lower than the reference voltage VDD2, is transmitted (output) to the input port of the control unit 60 through the input line 65. The control unit 60 performs control in the following manner, that is, the potential change of the input line 65 is detected, and the gate signal of the switching element M101 is controlled to allow or stop the power supply to the motor 35.

[0341] In this way, a circuit is provided on the power tool body 1A side to stop the motor 35 according to the discharge prohibition signal input through the LD terminals 168 and 28. However, when the power tool body 1A side has a control unit 60, it is preferred that the control unit 350 on the battery pack 100 side does not monitor the overcurrent to stop the motor 5 on the power tool body 1A side, but the control unit 60 on the power tool body 1A side directly monitors the overcurrent using the current detection circuit 64. In the case where the control unit 350 on the battery pack 100 side monitors the overcurrent, it is necessary to set an average control condition (overcurrent threshold) that can be applied to multiple power tool bodies. However, in the case where the control unit 60 on the power tool body 1A side monitors the overcurrent, the control condition (high overcurrent threshold) that is most suitable for the power tool body 1A can be set, so that the output limitation of the power tool caused by the control unit 350 setting the average control condition (low overcurrent threshold) can be avoided. The avoidance of the output limitation is particularly effective in new power tools that will be released in the future, and can achieve control that maximizes the capabilities of the new power tool body 1A.

[0342] In this embodiment, the control unit 350 on the battery pack 100 side determines whether the power tool body 1 or 1A on which the battery pack 100 is installed includes a control unit 60 having a microcomputer, and changes the overload protection condition for the battery pack 100 side according to the determination result. Fig.12In that case, when the electric tool body 1 does not include a microcomputer, the overcurrent limit value during low voltage output is set to a threshold value for the electric tool body 1A without a microcomputer, such as 20A (default value). The default value can be set appropriately according to the capacity or performance of the battery cell used. The overcurrent limit value is set to be equal to the value set in the previous battery pack 15, so the battery pack 100 of this embodiment can be used to drive the previous electric tool body 1A without a microcomputer. On the other hand, when the electric tool body 1A includes a microcomputer, the overcurrent limit value during low voltage output is not set on the battery pack 100 side, and the monitoring of the overcurrent value is entrusted to the microcomputer of the control unit 60 on the electric tool body 1A side. As a result, the control unit 60 can perform optimal current monitoring that is consistent with the characteristics of the motor 5 used or the structural characteristics of the electric tool body 1A, thereby avoiding the problem of being unable to effectively exert the capabilities of the electric tool body 1A due to excessive restriction of the overcurrent limit value on the battery pack 100 side. Moreover, the power tool body 1A can maximize the capacity of the battery pack 100 and realize a high-output power tool. Changing the overload protection conditions for the battery pack 100 side between the low voltage side and the high voltage side in this way means that not only is there room for further high output and further improvement of the low-voltage power tool body sold in the future, but also the control unit 60 on the power tool body side can perform the overload protection most suitable for the power tool body 1A.

[0343] In order to determine whether the power tool body 1 or 1A side includes a control unit 60 having a microcomputer, a new LD terminal voltage detection circuit 328 is provided, and the LD terminal voltage detection circuit 328 is used to detect the voltage value applied to the LD terminal 28. The LD terminal voltage detection circuit 328 is connected to the LD terminal 168 via a connecting line 342, and the LD terminal voltage detection circuit 328 outputs an output corresponding to the terminal voltage to the control unit 350. The microcomputer contained in the control unit 350 measures the LD terminal voltage after the battery pack 100 is installed and when the discharge prohibition signal 341 is not issued, thereby determining whether there is a control unit 60 including a microcomputer on the power tool body side. If the power tool body 1 does not have a microcomputer, then according to Fig.12 As can be seen from the circuit diagram, the LD terminal 28 is in a state where a voltage substantially equal to the voltage applied to the positive input terminal 22 is applied. The microcomputer of the control unit 350 detects the voltage of the upper positive terminal 162 through the upper cell unit voltage detection circuit 322, so by comparing the voltage of the upper positive terminal 162 with the LD terminal voltage, it is possible to determine whether the power tool body 1 includes a microcomputer. On the other hand, according to Fig.13It can be seen from the circuit diagram that if the power tool body 1A is equipped with a microcomputer, a voltage substantially equal to the reference voltage VDD2 (e.g., 5V or 3.3V) for driving the microcomputer is applied to the LD terminal 28. Therefore, the microcomputer of the control unit 350 does not even need to compare the voltage of the upper positive terminal 162 with the voltage of the upper battery cell voltage detection circuit 322. It can easily determine whether the power tool body 1A contains a microcomputer by detecting the LD terminal voltage. As described above, by setting the connecting wire 342 and the LD terminal voltage detection circuit 328, the control unit 350 can easily determine whether it is a tool that supports electronic control or a tool that does not support low-voltage drive control units such as microcomputers on the power tool body or electrical equipment body side. Moreover, the control unit 350 can change the control parameters used for battery cell monitoring, such as overload protection conditions, according to the judgment result. Here, the value of the changed control parameter only needs to be pre-stored in the non-volatile memory contained in the microcomputer, and any one of the stored values ​​can be read out and set according to the judgment result.

[0344] Fig.14 This is a circuit diagram of a state where a battery pack 100 is installed in an electric tool body 30 capable of supporting a high load. As a characteristic point of the electric tool body 30 capable of supporting a high load, it has device-side terminals (positive input terminal 52, negative input terminal 57, terminal portions 59b, 59c of short-circuit bar 59) corresponding to the positive terminals 162, 172 and negative terminals 167, 177 of the battery pack 100, respectively. The short-circuit bar 59 is a metal part having a terminal portion 59b at one end and a terminal portion 59c at the other end. When the battery pack 100 is installed on the side of the electric tool body 30, the lower positive terminal 172 and the lower negative terminal 177 are short-circuited through the short-circuit bar 59. In addition, the positive input terminal 52 of the electric tool body 30 is connected to the upper positive terminal 162, and the negative input terminal 57 is connected to the upper negative terminal 167. By using the shape of the body-side terminal that is divided into two parts like this, it is possible to obtain an output obtained by connecting the upper battery cell 146 and the lower battery cell 147 in series, that is, a rated 36V. Fig.13 The internal structure of the power tool body 1A shown is substantially the same. The motor 45 is a motor rated at 36V, but Fig.13 Similarly to the motor 35 shown in the figure, an inverter circuit can also be used to drive a brushless DC motor. A switch element M101 is provided in series with the power circuit for the motor 45. The switch element M101 is controlled to be turned on or off according to the gate signal output from the control unit 60. By turning off the switch element M101, the rotation of the motor 45 is stopped. In the high-voltage power tool body 30, the sending process of the discharge prohibition signal 341 from the battery pack 100 side is also the same as Fig.12 , Fig.13 The circuit shown is exactly the same. That is, by the control of the control unit 350 on the battery pack 100 side, the source-drain of the switch element M41 is turned on, and when the LD terminal 168 drops to the ground potential, its state is transmitted (output) to the input port of the microcomputer contained in the control unit 60, so that the control unit 60 can detect the discharge prohibition signal from the battery pack 100 side. However, in the 36V electric tool body 1, the discharge prohibition control based on overcurrent is performed by the control unit 60 on the tool body side, and the battery pack 100 side does not participate in the monitoring of overcurrent, or the stop threshold based on overcurrent is sufficiently increased to near the limit value of the battery cell, and the microcomputer of the control unit 350 can substantially not participate in the monitoring of the current value. As a result, it is possible to strike a good balance between further high output of the battery pack 100 and maintaining compatibility with the previous battery pack 15.

[0345] Next, use Fig.15 Other functions of the battery pack 100 will be described. Fig.15 The diagram is drawn with attention to the circuit for the control unit 350 to detect the poor contact state in the circuit structure within the battery pack 100. Figure 12 to Figure 14 The circuit diagram shown in FIG. 1 adds a lower voltage detection circuit 332, a connection state detection component 400, an upper cell unit discharge component (discharge circuit) 410, a lower cell unit discharge component (discharge circuit) 420, a system detection circuit 430, and a charge stop circuit 440. Due to the relationship between the diagram, the connection state detection component 400, the upper cell unit discharge component 410, and the lower cell unit discharge component 420 are shown in the diagram by separating the upper cell unit 146 from the lower cell unit 147, but the basic circuit structure is the same as Figure 12 to Figure 14 Same. However, omitted Figure 12 to Figure 14 The parts shown in the figure Fig.15 The features shown are not relevant to the illustration of the parts and must therefore be noted.

[0346] The upper cell unit 146 (cell group A) is connected to a protection IC 300 for the upper cell unit 146, and the lower cell unit 147 (cell group B) is connected to a protection IC 320 for the lower cell unit 147, and the control of these adjustments is performed by a control unit 350 including a microcomputer. Here, the following function is added, that is, a connection state detection component 400 is provided, and when a cell unit that cannot be charged or discharged occurs due to poor contact between the power connection terminal on the battery pack 100 side and the device side terminal on the electrical device body side or the connection terminal of an external charging device (not shown), the microcomputer of the control unit 350 detects this cell unit and stops charging or discharging. In this embodiment, two battery cells 146 and 147 are included, and connection terminals 161 or 162, 177, 171 or 172 and 167 for charging and discharging are respectively provided for each of these battery cells. The connection state of each battery cell is switched to series or parallel according to the terminal wiring embodiment of the target device connected to the charging and discharging terminals. In addition, when the external charging device is installed, the positive terminal pair 161 and 171 for charging is used instead of the positive terminal pair 162 and 172 for discharging. The upper positive terminals 161 and 171 are connected via a self-controlled protector, so they are at the same potential. Therefore, Fig.15 In the figure, for the sake of convenience, they are not distinguished from each other, and are described as the upper positive terminal 162 and the lower positive terminal 172. Here, when the output (rated 36V) in the series connection state is discharged, if the connection terminal for charging and discharging and the connection terminal on the power tool body side become poorly connected, no current will flow at all, so the power tool will not operate. Therefore, the operator can easily notice the occurrence of the poor connection state, so the battery pack 100 can be removed from the power tool body 1, 30 and installed again after cleaning the garbage, etc.

[0347] What is problematic is the discharge or charge of the output (rated 18V) in the parallel connection state. At this time, even if any one of the connection terminals for charging and discharging and the connection terminals on the power tool body side becomes poorly connected, there is still the possibility of continued discharge from one side of the two battery cells 146, 147 on the battery pack 100 side, or continued charging on one side. If only one of the battery cells is connected, and the poor connection state of the other battery cell continues, there will be a significant voltage imbalance between the upper battery cell 146 and the lower battery cell 147, which is not good. Therefore, the microcomputer monitors the voltage of the upper battery cell 146 and the lower battery cell 147 detected by the upper battery cell voltage detection circuit 322 and the lower battery cell voltage detection circuit 332, and uses the output signal of the connection state detection component 400 (connection state signal A345, connection state signal B346) to detect whether a poor connection has occurred in any of the connection terminals 162, 167, 172, 177. The poor contact state that must be detected as described above is when the upper battery cell 146 and the lower battery cell 147 are connected in parallel. Therefore, the connection point where the poor contact is likely to occur is the positive input terminal 22 (see FIG. 1 ) when the device on the other side to which the battery pack 100 is mounted is an 18V electric tool body 1. Figure 6 ) and the upper positive terminal 162, the positive input terminal 22 and the lower positive terminal 172, the negative input terminal 27 (refer to Figure 6 ) and the upper negative terminal 167, the negative input terminal 27 and the lower negative terminal 177.

[0348] First, the microcomputer included in the control unit 350 uses the upper cell unit voltage detection circuit 322 and the lower cell unit voltage detection circuit 332 to measure the voltage of the upper positive terminal 162 and the voltage of the lower positive terminal 172, and monitors the difference. Here, after the upper cell unit voltage detection circuit 322 sends a gate signal from the microcomputer and the switch element M82 becomes conductive, the voltage obtained by dividing the drain terminal of the switch element M82 and the positive potential (VbatA) of the upper cell unit 146 by two voltage-dividing resistors R81 and R82 is input to the gate signal of the switch element M81. Then, the switch element M81 changes from the blocking state to the connecting state, so that the positive potential (VbatA) of the upper cell unit 146 and the reference potential B (here, the negative potential of the lower cell unit 147) are connected, and the intermediate potential of the voltage-dividing resistors R83 and R84 therebetween is input to the microcomputer of the control unit 350 as the upper cell unit voltage 323. The microcomputer can measure the voltage value relative to the reference potential B using a built-in analog front end (AFE).

[0349] After the gate signal is sent from the microcomputer and the switch element M86 is turned on, the lower cell unit voltage detection circuit 332 inputs the voltage obtained by dividing the drain terminal of the switch element M86 and the positive potential (VbatB) of the lower cell unit 147 by two voltage-dividing resistors R85 and R86 to the gate signal of the switch element M85. As a result, the switch element M85 changes from a blocking state to a connecting state, so that the positive potential (VbatB) of the lower cell unit 147 and the reference potential B (negative potential of the lower cell unit 147) are connected, and the intermediate potential of the voltage-dividing resistors R87 and R88 therebetween is input as the voltage detection 333 of the upper cell unit to the microcomputer of the control unit 350. The microcomputer can use a built-in analog front end (AFE) to measure the voltage value relative to the reference potential B. As described above, the microcomputer measures the voltage of the upper cell unit 146 and the lower cell unit 147, but in order to minimize the power consumption at this time, the microcomputer sets the switch elements M82 and M86 to conduct only when measuring the voltage. The voltage detected by the upper cell unit voltage detection circuit 322 is not a potential relative to the reference potential A, but a relative potential to the reference potential B. The voltage detected by the lower cell unit voltage detection circuit 332 is also a relative potential to the reference potential B. When the potential of the lower negative terminal 177 is different from that of the upper negative terminal 167, for example, when the contact between the negative terminals 177 and 178 is poor, although it is determined that the potential on the positive side is equal, the voltage between the two ends of the upper cell unit 146 and the voltage between the two ends of the lower cell unit 147 may be different. The circuit provided to confirm whether there is a poor contact between any of the positive terminal and the negative terminal is the connection state detection component 400.

[0350] What can be detected by the connection state detection component 400 is the poor contact of the positive terminal. As a point that cannot be detected by the connection state detection component 400, it is either side of the negative terminal ( Figure 6 The power is blocked due to poor contact between the upper negative terminal 167 and the negative input terminal 27, or between the lower negative terminal 177 and the negative input terminal 27). When the power tool body 1 connected to the battery pack is an 18V device, from the perspective of the microcomputer of the control unit 350, even in a state where only the voltage of a single battery cell is applied, the voltage of another battery cell that has poor contact on the negative terminal side is sometimes detected as the same potential. For example, even in a case where the voltage between the two poles of the upper battery cell 146 is 18.0V and the voltage between the two poles of the lower battery cell 147 is 17.9V, when the reference potential A of the upper battery cell 146 is 0.1V lower than the reference potential B of the lower battery cell 147, the upper battery cell voltage detection circuit 322 and the lower battery cell voltage detection circuit 332 are both 18.0V and are equal.

[0351] In the connection state detection component 400, when the potential (reference potential A and reference potential B) on the negative side of the two battery cells 146 and 147 produces a specified difference, the switch element M60 is switched. The microcomputer can detect whether it is an abnormal state based on the switching of the switch element M60. For example, when the voltage of the upper battery cell 146 is high and the voltage of the lower battery cell 147 is low, the divided voltage of the two voltage-dividing resistors R61 and R62 provided between the reference potential A of the upper battery cell 146 and the reference potential B of the lower battery cell 147 is applied to the gate terminal of the switch element M61. Here, if there is no potential difference between the reference potential A and the reference potential B, the switch element M61 is still disconnected, but when the potential difference reaches a specified value or more, the switch element M61 becomes conductive. In addition, one end side of the voltage-dividing resistor R61 is connected to the negative electrode of the lower battery cell 147, but a switch element M60 is provided therebetween. The switch element M60 is a switching circuit for connecting or blocking the circuit to the voltage-dividing resistors R61, R62 and the voltage-dividing resistors R63, R64. When the microcomputer is started by supplying the drive signal VDD1 by inputting the microcomputer drive signal VDD1 to the gate signal, the switch element M60 is turned on accordingly. When the microcomputer is shut down, the switch element M60 is blocked. The resistor R65 is a grounding resistor for setting the gate-source to 0V when the gate signal of the switch element M60 becomes open.

[0352] When the switch element M61 becomes conductive, the voltage divided by the resistors R68 and R69 of the reference potential A of the upper battery cell 146 is applied to the gate signal of the switch element M62. Therefore, the voltage divided by the R70 and R72 of the positive potential (VbatA) of the upper battery cell 146 is input to the gate signal of the switch element M65. The drain terminal of the switch element M65 is connected to VDD1 via the resistor R71, and the source side is grounded to the reference potential B. Therefore, when the switch element M65 is disconnected, the connection state signal A345 is in a high state. When the switch element M65 becomes conductive, the connection state signal A345 becomes low. The connection state signal A345 is a signal indicating that poor contact has occurred on the negative terminal side. In the normal state (good contact of the negative terminal), it is high. Once it becomes low, it means that the negative side potential of the battery cell is inconsistent, so the microcomputer of the control unit 350 stops charging or discharging immediately.

[0353] Next, the operation when the voltage of the upper cell unit 146 decreases and the voltage of the lower cell unit 147 decreases will be described. This situation occurs when, for example, the power tool is connected to the 18V power tool body 1 and the power tool is operated to discharge from the battery pack 100. The upper negative terminal 167 and the negative input terminal 27 (see Figure 6 ) is poorly contacted, and discharge is only conducted from the upper battery cell 146 side, so that only the voltage of the upper battery cell 146 drops. In this state, since the positive side terminals 162 and 172 are commonly connected to the positive input terminal 22 and are at the same potential, the reference potential A becomes relatively higher relative to the reference potential B. As a result, the switching elements M61, M62, and M65 remain disconnected, but since the divided voltage of the resistors R63 and R64, which is the gate voltage of the switching element M63, reaches a specified value or more, the switching element M63 becomes conductive. The gate terminal of the switching element M63 is applied with a divided voltage of the lower positive terminal 172 of the lower battery cell 147 and the reference potential B divided by the resistors R66 and R74. However, the drain terminal of the switch element M63 is connected to this voltage dividing point, and the source terminal of the switch element M64 is connected to the source terminal of the switch element M63. Therefore, when the switch element M63 becomes conductive, the switch element M64 also becomes conductive, and the switch element M66 also becomes conductive. In addition, a switch element M64 is provided so that the voltage of each battery cell can be detected when the battery pack 100 is disassembled. A small value resistor R67 is added to the switch element M64. In this way, the negative potential of the upper battery cell 146 and the negative potential of the lower battery cell 147 can be compared via the switch element M64, so when the battery pack 100 is not connected, the balance of each battery cell can also be monitored. At the drain terminal of the switch element M64, the negative terminal 177 of the upper battery cell 146 is connected via the resistor R67 and the switch element M64. By turning on the switch element M66, VDD1 and the reference potential B are connected via the resistor R73, so the connection state signal B346 is switched from a high state to a low state. When the battery pack is not installed, the connection state signal B346 is not turned on by the switch element M63. The switch element M64 is not related to the detection, and since the switch element M66 is turned on, the connection state signal B346 becomes low. The connection state signal B346 also becomes low when the voltage is normally output by the parallel connection. As described above, the connection state detection component 400 can identify the poor contact state of the negative terminal 167, 177 side when the 18V connection is used.

[0354] In the state where the battery pack 100 is removed, that is, the upper positive terminal 162 and the lower positive terminal 172 are in an open state (non-conductive state), and similarly, the upper negative terminal 167 and the lower negative terminal 177 are in an open state (non-conductive state), the connection state signals A345 and B346 can be detected. When the drive voltage VDD1 is supplied from the power supply circuit 321 in this state and the microcomputer of the control unit 350 is started, a voltage is applied to the signal at the gate terminal of the switching element M60, so that the source-drain is conductive, and the negative side of the upper cell unit 146 and the negative side of the lower cell unit 147 are conductive through the parallel circuit of the voltage dividing resistors R61 and R62 and R63 and R64. As a result, the ground potentials of the upper cell unit 146 and the lower cell unit 147 become the same. In this state, M61 and M63 are in the disconnected state, so the switch elements M62 and M65 are also disconnected, and the connection state signal A345 becomes high. On the other hand, the switch element M64 remains in the disconnected state, but the battery voltage (VbatB) of the lower battery cell 147 is connected to the gate terminal of the switch element M66 via the voltage divider resistor R66, so the switch element M66 becomes conductive through the voltage divider voltage of the voltage divider resistor R66 and R74. Therefore, the connection state signal B346 becomes low. The above description is the operation of the connection state detection component 400.

[0355] Fig.15 The circuit shown includes a system detection circuit 430, which is used to detect which device the battery pack 100 is connected to, namely, an external charging device (not shown) or an electrical device body (e.g. Figure 1 The output of the system detection circuit 430 is input to the control unit 350. When the battery pack 100 is removed, the system detection signal 431 becomes high, and when it is installed in an external charging device (not shown) or an electrical device body, the system detection signal 431 becomes low. The switching element M92 inputs the LD terminal voltage to the gate signal, and a grounding resistor R94 is provided between the gate and the source. Here, the source terminal of the switching element M92 is grounded to the negative side of the lower battery cell 147. As shown by Fig.12 and Fig.13 As described above, when the electric tool body 1, 30 or other electric equipment is mounted, the voltage of the LD terminal 168 increases. As a result, the drain-source connection of the switch element M92 becomes conductive, so that the system detection signal 431 drops to the ground potential (reference potential B) and becomes low.

[0356] At the V terminal 165, the same method is used to detect the presence or absence of connection. If connected to an external charging device (not shown), a driving voltage (for example, 5V) for the control unit of the external charging device is applied to the V terminal 165. Therefore, in the system detection circuit 430, by detecting the presence or absence of voltage at the V terminal 165, it is possible to determine whether it is connected to the external charging device. Here, the switching element M91 inputs the V terminal voltage to the gate signal via the resistor R93. A grounding resistor R92 is provided between the gate and the source. Here, the source terminal of the switching element M92 is connected to the negative side of the lower battery cell 147, and the drain terminal is connected to the driving voltage (VDD1) via the input port of the microcomputer and the voltage divider resistor R91. It is illustrated here that the drain terminals of the switching elements M91 and M92 are connected to a common input port as a system detection signal 431. This input can be input through an OR circuit, or two input ports can be set on the microcomputer side to connect the drain terminals of the switch elements M91 and M92 respectively. A switching circuit can also be set to detect the outputs of the two switch elements M91 and M92 in sequence according to a time series through one input port.

[0357] As described above, by providing the system detection circuit 430 to detect whether the voltage value of the V terminal 165 or the LD terminal 168 becomes high, the microcomputer of the control unit 350 can determine whether the battery pack 100 is installed in the electrical equipment, installed in the charging tool, or in the non-installed state. When the battery pack 100 is in the non-installed state, the voltages of the V terminal 165 and the LD terminal 168 both become zero. When the battery pack 100 is installed in the electrical equipment, the microcomputer voltage or the battery voltage on the main body side is applied to the LD terminal signal, so that detection can be performed. If the microcomputer voltage of the external charging device is applied to the V terminal 165 in addition to the LD terminal, it can be determined that the battery pack 100 is connected to the external charging device. However, when the battery pack 100 is connected to the main body of the electric tool or the main body of the electric equipment without using the LD terminal 168, the detection using the system detection circuit 430 cannot be performed. In this case, the current detection circuit 327 is used to detect whether the installation is performed when the electric tool or the electric equipment is running or charging. In addition, when the microcomputer voltage of the target side device (power tool body or external charging device) is applied to both the V terminal 165 and the LD terminal 168, the microcomputer of the control unit 350 can determine that the battery pack 100 is connected to the target side device, but cannot identify whether it is the electrical device body or the external charging device. At this time, it is only necessary to determine whether it is a charging device or the electrical device body based on the current value detected by the current detection circuit 327. If a certain charging current flows, it can be determined as an external charging device, and by determining the direction of the current, it can also be determined whether it is an external charging device or the electrical device body. As described above, in either case, the microcomputer can accurately detect the system connection status.

[0358] The LD terminal 168 is further provided with a discharge stop circuit 435 and an LD terminal voltage detection circuit 328. The discharge stop circuit 435 includes a switch element M41, and the switch element M41 is used to short-circuit the LD terminal and the reference potential B via a resistor R46. When the operation of the electric tool must be abnormally stopped, the microcomputer of the control unit 350 changes the discharge prohibition signal 341 from low to high. Since the discharge prohibition signal 341 is a gate signal of the switch element M41, when the discharge prohibition signal 341 becomes high, the potential of the LD terminal 168 is grounded via the resistor R46, thereby becoming a low potential. The LD terminal voltage detection circuit 328 is as shown by Fig.12 , Fig.13 Therefore, repeated description is omitted here.

[0359] The charging stop circuit 440 is provided to transmit (output) a signal to stop the charging action of the external charging device through the LS terminal 166 under the control of the microcomputer of the control unit 350. The LS signal is used for the charging device, and therefore is not used when connected to the power tool body 1, 30. The charging stop signal 441 is usually low, but during charging, when the microcomputer on the battery pack 100 side determines that the charging action should be stopped, in order to transmit (output) this judgment to the charging device, the charging stop signal 441 is switched from low to high. When the microcomputer of the control unit 350 switches the charging stop signal 441 to high, the switching elements M95 and M96 whose gate signals are input with the charging stop signal 441 both become conductive. When the switching element M95 becomes conductive, the V terminal 165 and the reference potential B are conductive, thereby transmitting (outputting) the divided voltage of the resistors R96 and R97 interposed therebetween to the gate terminal of the switching element M93, so that the switching element M93 is conductive. Furthermore, since the switch element M96 is turned on, the gate potential of the switch element M94 drops to the ground (reference potential B), and the source-drain of the switch element M94 is blocked. As a result, the output of the thermistor TH1 is blocked from being transmitted (output) from the LS terminal 166 to the charging device (not shown) (normal state). On the other hand, since the switch element M93 is turned on, the LS terminal 166 and the V terminal 165 become the same potential, that is, become high. At the LS terminal 166, there is a voltage dividing resistor (not shown) for dividing the power supply voltage 5V on the charging device side. When the battery pack 100 is not connected to the charging device, a divided voltage of about 3V is output to the LS terminal on the charging device side. When the battery pack 100 is installed in the charging device, in the normal state (normal charging), a value lower than 3V is transmitted (output) to the LS terminal 166, but once an abnormal state (a state where charging should be stopped) occurs on the battery pack 100 side, the microcomputer of the control unit 350 sets the LS terminal voltage to a value higher than 3V. As a result, the external charging device detects that the state of LS terminal 166 has become high, thereby stopping charging.

[0360] The battery pack 100 includes a voltage adjustment component that balances the voltages of the upper cell unit 146 and the lower cell unit 147 when the control unit 350 detects that the voltages of the upper cell unit 146 and the lower cell unit 147 are different. To achieve voltage balance, the cell unit with a higher voltage is discharged. The discharge component A410 is a discharge component included in the circuit of the upper cell unit 146, and the discharge component B420 is a discharge component included in the circuit of the lower cell unit 147. Each of them can be discharged at any time and for any period by sending a discharge execution signal A411 or a discharge execution signal B421 from the microcomputer of the control unit 350. The discharge component A410 is composed of a dummy resistor R51 for discharge, which is connected to the positive and negative electrodes of the upper cell unit 146 and consumes power by converting current into heat. Here, as the dummy resistor R51, for example, a 2kΩ resistor is used. If the actual voltage of the upper cell unit 146 is 20V, a current of 10mA flows through the resistor, so it can be adjusted in the following manner, that is, it takes a long time of several days to a week to reduce the potential of the upper cell unit 146 side to become the same as the lower cell unit 147. The switch element M51 is a switch for connecting or blocking the resistor R51, and the divided voltage of the resistors R52 and R53 is input to the gate terminal of the switch element M51. The resistor R52 is connected to the reference potential B of the lower cell unit 147 via the switch element M52. The discharge execution signal A411 from the control unit 350 is input to the gate terminal of the switch element M52.

[0361] The discharge component B420 is composed of a dummy resistor R54 for discharge, and the dummy resistor R54 is connected to the positive electrode and the negative electrode of the lower battery cell 147. The value and operation principle of the dummy resistor R54 are the same as those of the discharge component A410. The switch element M54 is a switch for connecting or blocking the resistor R54, and the discharge execution signal B421 from the control unit 350 is directly input to the gate terminal.

[0362] Next, use Fig.16 The flow chart of FIG. 1 is used to describe the process of determining whether the connection state of the connection terminal of the battery pack 100 is normal or abnormal by the microcomputer of the control unit 350. Fig.16The process shown can be executed in software by a program pre-stored in the microcomputer of the control unit 350. Once the microcomputer is started, it is executed together with other control programs, and its execution continues until the microcomputer is shut down. First, the microcomputer uses the system detection circuit 430 to determine whether the battery pack 100 is connected to the main body of an electrical device such as an electric tool body or an external charging device (step 501). If it is connected, the system detection signal 431 becomes low, and if it is not connected, it is high. Next, the microcomputer measures the voltage detection 323 of the upper battery cell voltage detection circuit 322 and the voltage detection 333 of the lower battery cell voltage detection circuit 332, and compares their measurement results (step 502). Next, the microcomputer detects the two output signals of the connection status detection component 400, namely the connection status signal A345 and the connection status signal B346 (step 503). Next, the microcomputer measures the current flowing through the lower battery cell 147 based on the output of the current detection circuit 327 (step 504). Next, the microcomputer uses the detection results of steps 501 to 504 to determine whether the connection state of the battery pack 100 and the terminal connection state are normal or abnormal, and performs actions corresponding to the determination results (steps 505 and 506). The determination method in step 506 and the corresponding action at this time are summarized as follows: Fig.17 .

[0363] Fig.17 This is a table showing the determination of the connection state of the battery pack 100 by the microcomputer of the control unit 350, the determination method of whether the terminal connection state is normal or abnormal, and the response action to the determination result. Here, the determination is divided into the modes shown in No. 1 to 11, but the number of determination divisions can be further increased, and it can be further simplified to 11 divisions or less. Fig.16 As shown in step 501, it is first determined whether there is a system connection. Here, the determination can be made based on whether the output of the system detection circuit 430 is low (L: system detection) or high (H: no system detection). Therefore, it is first distinguished whether it is mode No. 1 to 8 or 9 to 11. Here, the so-called no system detection (H) means that the battery pack 100 is removed from the electrical device body or the external charging device.

[0364] exist Fig.16 In step 502, the microcomputer determines whether there is a system connection. Here, if the voltages of the upper battery cell 146 and the lower battery cell 147 are equal or within a specified range (within ±0.5V), a condition for judging that the battery pack 100 is in a normal state is satisfied. Fig.16In step 503, the microcomputer detects the connection status signals A345 and B346. The connection status signal A345 is high (H) in normal conditions and low (L) in abnormal conditions. Therefore, if there is a combination in which it is L (No. 8 here), it is immediately determined to be an abnormal state at this point in time. This state is equivalent to a situation in which only the upper battery cell 146 is charged, or a situation in which only the lower battery cell is discharged. The connection status signal B346 is a determination signal as described below, that is, when the connection status signal A345 is high (H) indicating a normal state, this connection status signal B346 is high (H) in a series connection state, and is low (L) in a parallel connection state or a disassembled state.

[0365] When the system detection is H (no), if the voltage between the battery cells is within ±0.5V, as shown in mode No. 9, the judgment result is "(battery pack 100) not connected / (electrode status) normal", and the microcomputer of the control unit 350 does not perform any operation and stands by. In addition, when the system detection is H (no) and the voltage between the battery cells is 1V or more, if the voltage A of the upper battery cell 146 is higher than the voltage B of the lower battery cell 147, as shown in mode No. 10, the judgment result is "non-connection / battery group voltage balance abnormal (A>B)". At this time, the discharge component A410 is operated to discharge the upper battery cell 146, and the voltage balance between the battery cells is adjusted. Once the result of the adjustment is that the voltage imbalance between the battery cells is within ±0.5V, the discharge operation of the discharge component A410 is released. Similarly, when the system detection is H (none) and the voltage A of the upper cell unit 146 is higher than the voltage B of the lower cell unit 147, as shown in mode No. 11, the judgment result is "non-connection / cell group voltage balance abnormality (A < B)". At this time, the discharge component B420 is operated to discharge the lower cell unit 147 to adjust the voltage balance between the cell units. Once the result of the adjustment is that the voltage imbalance between the cell units is within ±0.5V, the discharge operation of the discharge component B420 is released.

[0366] When the system detection is L (yes) and the connection status signal B346 is H (high), it means that the battery pack is connected to a 36V device and the battery cells are connected in series. When connected to a 36V device, the potential on the negative side of the upper battery cell 146 is higher than the potential on the negative side of the lower battery cell, so the switch element M63 of the connection status detection component 400 becomes conductive and the switch element M66 becomes disconnected, so the connection status signal B346 becomes high (H). Therefore, this mode is equivalent to any one of No1 to 3. At this time, it is determined that the potential difference between the upper battery cell 146 and the lower battery cell 147 is within the first specified value, for example, within ±0.5V. Here, if the first specified value (= detection range) is set to 0 or close to 0, hunting will occur, so the allowable range is determined. Here, the voltage of the battery cell is 18.0V, so the first specified value is set to about 0.5 (V). If the potential difference is within ±0.5V, it is "series connection (36V) / normal" as shown in mode No.1, so the microcomputer of the control unit 350 does not perform control for voltage adjustment and stands by. If the potential difference between the upper battery cell 146 and the lower battery cell 147 is greater than the second specified value, for example, there is a difference of more than 1V, it is determined as "series connection (36V) / battery cell group voltage balance abnormality". Mode No.2 is a case where the voltage of the upper battery cell (battery cell group A) 146 is high, and mode No.3 is a case where the voltage of the lower battery cell (battery cell group B) 147 is high. In the case of mode No.2, the control unit 350 sets the discharge execution signal A411 to high and operates the discharge component A410 to perform voltage adjustment (discharge of the upper battery cell 146). Similarly, in the case of mode No. 3, the control unit 350 sets the discharge execution signal B421 to high to operate the discharge component B420 to perform voltage adjustment (discharge of the lower battery cell 147). In mode No. 2 or 3, once the potential difference between the upper battery cell 146 and the lower battery cell 147 reaches the first potential difference (here, within 0.5V), the operation of the discharge component A410 or the discharge component B420 is stopped. In addition, when a large discharge current is detected by the current detection circuit 327, that is, the state in which the trigger of the power tool is pulled or the operation of the electrical equipment is started, the operation of the discharge component A410 or the discharge component B420 is temporarily released.

[0367] When the system detects L (yes) and the connection status signal B346 is L (i.e., parallel connection), it is determined whether the potentials of the upper battery cell 146 and the lower battery cell 147 are the same. If there is no potential difference (0V), as shown in mode No. 4, it is "parallel connection (18V) / normal", so the microcomputer of the control unit 350 does not perform control for voltage adjustment and stands by. If the potential difference between the upper battery cell 146 and the lower battery cell 147 is greater than the second specified value, for example, there is a difference of more than 1V, it is determined as "parallel connection (18V) / battery cell group voltage balance abnormality". Mode No. 5 is a case where the voltage of the upper battery cell (battery cell group A) 146 is high, and mode No. 6 is a case where the voltage of the lower battery cell (battery cell group B) 147 is high. In the case of mode No. 5, the control unit 350 sets the discharge execution signal A411 to high and operates the discharge unit A410 to adjust the voltage (discharge the upper cell 146). Similarly, in the case of mode No. 6, the control unit 350 sets the discharge execution signal B421 to high and operates the discharge unit B420 to adjust the voltage (discharge the lower cell 147). In mode No. 5 or 6, if the system detection switches from L to H during voltage adjustment, that is, if the battery pack 100 is removed, the discharge operation in mode No. 5 or 6 is stopped. In addition, when the potential difference between the upper cell 146 and the lower cell 147 reaches the first potential difference (here, within 0.5V), the operation of the discharge unit A410 or the discharge unit B420 is stopped. Furthermore, when a large discharge current is detected by the current detection circuit 327, that is, when the trigger of the electric tool is pulled or the operation of the electrical equipment is started, the operation of the discharge component A410 or the discharge component B420 is temporarily released.

[0368] In addition, there is a case where, although in a parallel connection state, due to poor contact on the negative terminal side of the cell unit, the voltage of the upper cell unit 146 and the lower cell unit 147 appear to be equal. This is mode No. 7, and both the connection state signal A345 and the connection state signal B346 are high (H). At this time, at first glance, it is the same as the combination of mode No. 1, but the microcomputer of the control unit 350 detects the voltage of the upper cell unit 146 (see the upper cell unit voltage detection circuit 322) as described above. Fig.12 ) to monitor the voltage of the upper cell unit 146. Similarly, the lower cell unit protection IC 320 (see Fig.12) to monitor the voltage of the upper battery cell 146. Therefore, even if the connection status signal A345 and the connection status signal B346 are both high (H), the microcomputer can determine whether it is mode No. 1 or No. 7 by coordinating the results of determining whether it is in a series connection or a parallel connection state. If it is determined to be mode No. 7, it is "parallel connection (18V) / -terminal contact abnormality / +terminal contact normal", so the microcomputer of the control unit 350 transmits (outputs) a signal to the device side connected via the LD terminal 168 or the LS terminal 166 to stop the charging and discharging action. This state is equivalent to the situation where only the upper battery cell 146 is discharged or only the lower battery cell is charged. In mode No. 7, once the system detection signal is detected to be H (none), the charging and discharging action is stopped.

[0369] Fig.18 This is a time chart for further explaining the operation of the battery pack 100. The horizontal axis represents the passage of time (unit: seconds), the top column represents the connection state or installation state of the battery pack 100, and the bottom column represents the connection state or installation state of the battery pack 100 with numbers ① to Indicates the moment when the state of the battery pack 100 is changed. Here, the following state is shown, that is, the removed battery pack 100 is installed in the 36V power tool body 30 in ②, removed again in ⑤, installed in an external charging device in ⑦, removed from the external charging device in ⑨, installed in the 18V power tool body 1 in ⑩, and Remove again.

[0370] The system detection signal 431 indicates the output signal of the system detection circuit 430 included in the battery pack 100. The system detection circuit 430 has two states, high (H) and low (L). When the battery pack 100 is installed in some equipment, i.e., the power tool body 1, 30, or an external charging device (not shown), the system detection circuit 430 becomes low as shown by arrows 431a, 431c, and 431e, and when the battery pack 100 is removed, the system detection circuit 430 becomes high as shown by arrows 431b, 431d, and 431f.

[0371] The voltage imbalance detection signal 344 indicates which of the voltages of the upper cell unit 146 and the lower cell unit 147 is higher than a predetermined amount, which is 0.5V or more in this case. If an imbalance is detected, the voltage becomes higher, and if no imbalance is detected, the voltage becomes lower. Here, the period from ① to ⑥ indicates that the voltage A of the upper cell unit 146 is lower than the voltage B of the lower cell unit 147 by 0.5V or more, as shown by arrow 344a, and the period from ⑨ to ⑩ is the same as the period from ⑨ to ⑩. to As shown by arrows 344c and 344e, the voltage A of the upper cell unit 146 is higher than the voltage B of the lower cell unit 147 by 0.5V or more. The difference between the voltage A of the upper cell unit 146 and the voltage B of the lower cell unit 147 falls within a predetermined range, that is, is less than 0.5 V, and the voltage imbalance detection signal 344 becomes low as indicated by arrows 344 b and 344 d .

[0372] The connection status signal A345 and the connection status signal B346 are Fig.14 The output signals of the connection state detection component 400 shown in the circuit diagram are input to the microcomputer of the control unit 350. The connection state signal A345 is as follows: Fig.14 As mentioned above in the description, it is usually high (H) as shown by arrows 345a, 345c, and 345e, and becomes low (L) when poor contact occurs on the negative terminal side when connected in parallel. Here, at timing ⑧ and timing ⑩, it indicates a state where poor contact occurs on the negative terminal side. At this time, as shown by arrows 345b and 345d, the connection status signal A345 becomes low (L). When the connection status signal A345 is high (H) indicating a normal state, the connection status signal B346 becomes high (H) in the series connection state, and becomes low (L) in the parallel connection state or the disassembled state. Therefore, it becomes high (H) at arrow 346a, and otherwise becomes low (L) as shown by arrow 346b.

[0373] The discharge execution signal A411 of the discharge part A is an indication Fig.14 The discharge execution signal A411 is a signal for the operation of the discharge component A410. When the discharge execution signal A411 is high as shown by arrows 411b and 411d, the discharge component A410 operates (starts up). When the discharge execution signal A411 is low as shown by arrows 411a and 411c, the discharge component A410 does not operate (turns off). The discharge component B420 is an instruction Fig.14 The discharge current 349 is the signal for the action of the discharge component B420. When the discharge execution signal B421 is high, the discharge component B420 operates (starts up). When it is low, the discharge component B420 does not operate (turns off). Fig.14 The output of the current detection circuit 327 shown in FIG. 1 is a current value on the vertical axis. When the trigger switch of the electric tool is pulled and the motor rotates, a large starting current flows as shown by arrows 349a, 349d, and 349g, and then a substantially constant current flows as shown by arrows 349b, 349e, and 349h. When the operator releases the trigger switch, the current becomes substantially zero as shown by arrows 349c, 349f, and 349i. The value of the discharge current 349 is only an example, and the actual current waveform varies depending on each electric tool body and, in turn, varies greatly depending on the content of the operation.

[0374] When the microcomputer of the control unit 350 detects that the discharge current 349 flows three times as shown in the figure, the microcomputer stops the operation of the discharge component A410 and the discharge component B420 while they are in operation. Fig.16 Taking the example of , after ①, according to the voltage imbalance detection signal 344, the voltage A of the upper battery cell 146 is lower than the voltage B of the lower battery cell 147, so as shown by arrow 421a, the discharge component B420 becomes started (operating state). On the other hand, as shown by arrow 411a, the discharge component A410 remains closed (non-operating). During the operation of the discharge component B420, if at timing ③, the microcomputer of the control unit 350 detects the action of the trigger switch, the microcomputer immediately stops the action of the discharge component B420 as shown by arrow 421b. Then, if a fixed time T has passed after the operation of the trigger lever is released, as shown by ④, the discharge component B420 is set to start (operating state) again. Similarly, at arrows 421c and 421e, after the trigger lever operation becomes disconnected and a specified time T has passed, the discharge component B420 also becomes started (operating state). In addition, Fig.16 In the example of , the situation where voltage A is less than voltage B and the discharge component B420 side is operated is described. However, even if voltage A is greater than voltage B and the discharge component A410 side is operated, the discharge component A420 is activated (operation state) after the trigger lever operation is turned off and the prescribed time T has passed. From ⑤ to ⑥, the discharge component B420 operates, and from ⑨ to ⑩, Until now, the discharge unit A410 is in operation, but at this time the battery pack 100 is removed, so the control unit 350 performs the voltage adjustment operation without affecting devices other than the battery pack 100.

[0375] The charge / discharge prohibition signal 453 is an output for prohibiting the operation of the power tool body 1, 30 or the charging device (not shown) connected to the battery pack 100. The charge / discharge prohibition signal 453 for the power tool body 1, 30 is Fig.14 The discharge prohibition signal 341 for the charging device (not shown) is Fig.14 Here, at ⑧, in order to instruct the charging device to stop charging, a charge and discharge prohibition signal 453 is sent as shown by arrow 453b, and at ⑩, in order to instruct the 18V electric tool body 1 to prohibit discharge, a charge and discharge prohibition signal 453 is sent as shown by arrow 453d.

[0376] As described above, in this embodiment, the voltages of the upper cell unit 146 and the lower cell unit 147 included in the battery pack 100 are compared to discharge the high voltage side cell, thereby ensuring that the voltages of the cell units are equal. Furthermore, in the parallel connection state of the cell units, even in the process of discharging or charging, the occurrence of poor contact between the connection terminals can be detected, so that the discharge or charging can be stopped quickly when poor contact occurs.

[0377] [Example 2]

[0378] Next, the second embodiment of the present invention will be described using Embodiment 2. In the first embodiment, the voltage imbalance between the upper cell unit 146 and the lower cell unit 147 in the battery pack 100 is detected by the microcomputer of the control unit 350 in the battery pack 100. In the second embodiment, the detection is performed by the microcomputer on the electrical device body side. Fig.19 It is a schematic diagram showing an electric tool according to a second embodiment of the present invention. Fig.19 The electric tool 1 in (1) is an electric tool operated at a rated voltage of 18V, and the load device including the motor 5 is operated by the power outputted in parallel by the battery pack 100. Here, the voltage of the upper battery cell 146 and the lower battery cell 147 connected in parallel is applied to the motor 5, and the mechanism 6 is driven.

[0379] Fig.19 The electric tool 630 of (2) is composed of a control unit (device-side control unit) including a microcomputer 660. The microcomputer (MCU) 660 monitors the voltage supplied to the motor 635, that is, the voltage between the positive electrode of the upper battery cell 146 and the negative electrode of the lower battery cell 147. Furthermore, the microcomputer 660 is configured to be able to measure the intermediate potential between the upper battery cell 146 and the lower battery cell 147. The intermediate potential can be obtained by inputting the potential of the short-circuit bar 689 into the microcomputer 660. By measuring the intermediate potential by the microcomputer 660 in this way, the voltage of the upper battery cell 146 and the voltage of the lower battery cell 147 are compared, and it is possible to detect whether there is a voltage imbalance between the battery cells. If the voltage difference is greater than a specified value, it can also be determined that an abnormality has occurred in the connection of multiple battery cells. Furthermore, once the voltage difference between the upper cell unit 146 and the lower cell unit 147 reaches a predetermined threshold value (e.g., 1V or more), the microcomputer 660 stops and prohibits the operation of the motor 635, thereby stopping or limiting the power supply from the battery pack 100 to the load device (motor 635). In addition, as an alarm indicating that the discharge is stopped, the LED 665 is flashed to inform the operator that an abnormality has occurred. Fig.19In (2) of FIG. 1 , as a notification component indicating that the discharge has stopped, i.e., the electric tool has stopped operating, an LED 665 for notifying by light is used, but it may also be Fig. 20 As shown in the electric tool 630A, a buzzer component 665A is used to notify through sound.

[0380] The present invention has been described above based on a plurality of embodiments, but the present invention is not limited to the embodiments, and various changes can be made without departing from the main purpose thereof. For example, in the embodiments, a voltage switching battery pack of 18V and 36V is described, but the switching voltage or voltage ratio is not limited thereto, and other voltage ratios can also be used. Moreover, the circuit structure of the upper battery cell voltage detection circuit 322, the lower battery cell voltage detection circuit 332, the connection state detection component 400, the discharge component A410, and the discharge component B420 is not limited to the ones described above, and equivalent functions can also be achieved by other circuit structures.

Claims

1. A battery pack, characterized in that: include: The first battery cell unit is formed by connecting a plurality of battery cells in series in units; The second battery cell unit is formed by connecting a plurality of battery cells in series in units; A first positive terminal connected to the positive electrode of the first battery cell unit; A first negative terminal connected to the negative electrode of the first battery cell unit; A second positive terminal connected to the positive electrode of the second battery cell unit; A second negative terminal connected to the negative electrode of the second battery cell unit; signal terminal; as well as Microcomputer, In the battery pack, When the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the high voltage electrical equipment body, the first battery cell unit and the second battery cell unit are connected in series. On the other hand, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the low voltage electrical equipment body, the first battery cell unit and the second battery cell unit are connected in parallel. In this way, the connection state of the first battery cell unit and the second battery cell unit can be switched. In the parallel connection state, when discharge continues from only one of the first battery cell and the second battery cell to the low-voltage electrical device body and a voltage imbalance occurs between the first battery cell and the second battery cell, the microcomputer is configured to output a signal for stopping the discharge to the low-voltage electrical device body through the signal terminal.

2. The battery pack according to claim 1, characterized in that: Also includes: A first protection integrated circuit connected to the first battery cell unit; as well as A second protection integrated circuit connected to the second battery cell unit; in, The output from the first protection integrated circuit and the output from the second protection integrated circuit are input to the microcomputer, The microcomputer outputs the signal to the connected electrical equipment body.

3. The battery pack according to claim 1, characterized in that: Also includes: The protection circuit is set for the first battery cell unit and the second battery cell unit to monitor the voltage of the battery cell. The microcomputer is connected to the protection circuit to monitor the load state of the battery cell.

4. The battery pack according to claim 1, characterized in that: Also includes: Power supply circuit, The power supply circuit is connected to a lower cell unit located on a ground line side in a state where the first cell unit and the second cell unit are connected in series, and supplies power to the microcomputer.

5. The battery pack according to claim 1, characterized in that: When a temperature difference between the first cell unit and the second cell unit exceeds a threshold value, or when a current difference between the first cell unit and the second cell unit exceeds a threshold value, the microcomputer outputs a signal for stopping the discharge.

6. The battery pack according to claim 1, characterized in that: Also includes: a first voltage detection circuit connected to the first positive terminal; as well as a second voltage detection circuit, connected to the second positive terminal, in, Outputs from the first voltage detection circuit and the second voltage detection circuit are input to the microcomputer.

7. The battery pack according to claim 6, characterized in that: The microcomputer detects voltages of the first positive terminal and the second positive terminal using outputs from the first voltage detection circuit and the second voltage detection circuit.

8. The battery pack according to claim 1, characterized in that: Also includes: A system detection circuit detects whether the battery pack is installed in the electrical device body or an external charging device. The system detection circuit is used to detect poor contact with the device-side terminal of the electrical device body on which the battery pack is mounted.

9. The battery pack according to claim 1, characterized in that: Also includes: The connection state detection circuit detects whether any of the positive terminal or the negative terminal of the battery pack has poor contact by comparing the potentials of the negative electrode side of the first battery cell unit and the second battery cell unit.

10. The battery pack according to claim 1, characterized in that: Also includes: a system detection circuit for detecting whether the battery pack is installed in the electrical device body or an external charging device, the system detection circuit being used to detect poor contact with the device-side terminal of the electrical device body on which the battery pack is installed; as well as The first voltage detection circuit and the second voltage detection circuit detect voltage values ​​of the first battery cell unit and the second battery cell unit respectively relative to the low-side ground line. in, The microcomputer uses the outputs of the system detection circuit, the first voltage detection circuit, and the second voltage detection circuit to determine whether there is a battery cell that cannot be charged or discharged due to poor contact between any one of the first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal and the device side terminal.

11. The battery pack according to claim 1, characterized in that: Also includes: Remaining capacity display component, showing the remaining battery power, The remaining battery capacity is displayed based on a voltage across one of the first battery cell unit and the second battery cell unit, or based on a lowest voltage value among the plurality of battery cells.

12. An electrical device body, capable of connecting the battery pack according to any one of claims 1 to 11, wherein the electrical device body comprises: The device side terminal; A device-side signal terminal connected to the signal terminal; as well as load, connected to the device side terminals, in, When the signal is input through the device-side signal terminal, the operation of the load is stopped.

13. The electrical equipment body according to claim 12, characterized in that: Also includes: a switching element, arranged in series with the load, When the signal is input through the device-side signal terminal, the switch element is blocked to stop the operation of the load.

14. The electrical equipment body according to claim 13, characterized in that: Also includes: The device-side microcomputer controls the switch element. The device-side microcomputer is configured to output a blocking signal to block the switch element when the signal is input through the device-side signal terminal.

15. An electrical device comprising: a battery pack and an electrical device body to which the battery pack can be connected, wherein: The battery pack comprises: The first battery cell unit is formed by connecting a plurality of battery cells in series in units; The second battery cell unit is formed by connecting a plurality of battery cells in series in units; A first positive terminal connected to the positive electrode of the first battery cell unit; A first negative terminal connected to the negative electrode of the first battery cell unit; A second positive terminal connected to the positive electrode of the second battery cell unit; A second negative terminal connected to the negative electrode of the second battery cell unit; signal terminal; as well as Microcomputer, The electrical equipment body comprises: a plurality of device-side terminals connected to each of the first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal; a device-side signal terminal connected to the signal terminal; and load, connected to the device side terminals, In the battery pack, When the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the high voltage electrical equipment body, the first battery cell unit and the second battery cell unit are connected in series. On the other hand, when the first positive terminal, the first negative terminal, the second positive terminal and the second negative terminal are connected to the device side terminal of the low voltage electrical equipment body, the first battery cell unit and the second battery cell unit are connected in parallel. In this way, the connection state of the first battery cell unit and the second battery cell unit can be switched. In the case of the parallel connection state, when only one of the first battery cell and the second battery cell continues to discharge to the low-voltage electrical device body and a voltage imbalance occurs between the first battery cell and the second battery cell, the microcomputer is configured to output a signal for stopping the discharge to the low-voltage electrical device body through the signal terminal. The low-voltage electrical device body is configured to stop the load when the signal is input.

16. The electrical device according to claim 15, characterized in that The battery pack further comprises: A first protection integrated circuit connected to the first battery cell unit; and A second protection integrated circuit connected to the second battery cell unit; in, The output from the first protection integrated circuit and the output from the second protection integrated circuit are input to the microcomputer, The microcomputer outputs the signal to the connected electrical equipment body.

17. The electrical device according to claim 15 or 16, characterized in that: The electrical equipment body further comprises: a switch element connected in series with the load, The electrical device body is configured to block the switching element and stop the operation of the load when the signal is input through the device-side signal terminal.

18. The electrical device according to claim 17, characterized in that The electrical device body further includes: a device-side microcomputer that controls the switch element, The device-side microcomputer is configured to output a blocking signal to block the switch element when the signal is input through the device-side signal terminal.

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