Battery pack and electrical device using battery pack

Abstract

To provide a battery pack capable of switching the connection state of a plurality of battery cells.SOLUTION: A first and second cell units 146 and 147 composed of a plurality of cells are housed, the first cell unit 146 is connected to an upper positive terminal 162 and a lower negative terminal 177, a second cell unit 147 is connected to a lower positive terminal 172 and an upper negative terminal 167, and a power supply circuit 321 for a microcomputer 350 is electrically connected to the lower positive terminal 172 and the upper negative terminal 167 of the cell unit 146 on one side of the first and second cell units.SELECTED DRAWING: Figure 21

Description

[Technical field]

[0001] The present invention relates to an electric device having a load such as a motor or lighting, and a battery pack for supplying power to such an electric device. [Background technology]

[0002] Electrical devices such as power tools are increasingly being powered by battery packs using secondary batteries such as lithium-ion batteries, and electrical devices are becoming increasingly cordless. For example, in a handheld power tool that drives a tool tip using a motor, a battery pack containing multiple secondary battery cells is used, and the motor is driven by the electrical energy stored in the battery pack. The battery pack is configured to be detachable from the power tool body, and when the voltage drops due to discharge, the battery pack is removed from the power tool body and charged using an external charging device.

[0003] Cordless power tools and electrical equipment are required to have a certain operating time and a certain output, and secondary batteries have been improved in performance to achieve higher output and voltage. In addition, as electrical equipment powered by battery packs has been developed, battery packs of various voltages have been commercialized. Normally, the output voltage of a battery pack is fixed, but Patent Document 1 proposes a power supply device for electrical equipment that can be used with equipment of different voltages by providing multiple battery units in a housing that contains the batteries and allowing a connection means to select whether the battery units are output as a series connection or a parallel connection. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-17954 A Summary of the Invention [Problem to be solved by the invention]

[0005] For users, preparing multiple types of battery packs when using multiple electrical devices is cumbersome, and there is a need for a user-friendly battery pack that can be used with electrical devices of different voltages by switching the voltage. Moreover, there has been a need to realize a voltage switching system with a battery pack that can be easily attached to an electrical device, rather than a power supply device separate from the electrical device body as in Patent Document 1.

[0006] The present invention has been made in consideration of the above-mentioned background, and an object of the present invention is to provide a battery pack that has a switchable output voltage so that it can be shared between electrical devices of different voltages, and an electrical device using the same. Another object of the present invention is to provide a battery pack that can be attached to an electric device body and that is capable of switching the connection state of a plurality of cell units. Another object of the present invention is to provide a battery pack equipped with a control unit that can control discharging or charging of the battery pack while monitoring the states of a plurality of cell units. Another object of the present invention is to provide a battery pack that can stably control discharging or charging the battery pack regardless of the connection state of a plurality of cell units. Another object of the present invention is to provide a battery pack and an electrical device using the same, which balances the current consumption among multiple cell units contained in the battery pack and which is capable of switching between high and low output voltages. It is still another object of the present invention to provide a battery pack in which a microcomputer is provided in any one of the battery cell protection circuits provided for each of a plurality of cell units. It is still another object of the present invention to provide a battery pack that can efficiently utilize the capabilities of an electric device. It is still another object of the present invention to provide a high-performance battery pack. It is still another object of the present invention to provide a battery pack having a terminal structure that can be satisfactorily fitted into a connecting terminal on the main body of an electric device. [Means for solving the problem]

[0007] Representative features of the invention disclosed in this application are as follows. According to one aspect of the present invention, a battery pack includes: The battery pack includes a first cell unit and a second cell unit in which a plurality of battery cells are connected in series, a pair of first terminals electrically connected to the first cell unit and directly fitted to a first device terminal of an electric device body, a pair of second terminals electrically connected to the second cell unit and directly fitted to a second device terminal of the electric device body, a remaining capacity display unit configured to display a remaining battery capacity of the battery pack, and a switch configured to be operated by an operator. The first and second cell units are configured to be switchable between a non-connected state in which the pair of first terminals and the pair of second terminals are not fitted to the first and second device terminals and the first and second cell units are not electrically connected to each other, and a series-connected state in which the pair of first terminals and the pair of second terminals are directly fitted to the first and second device terminals and the first and second cell units are connected in series to each other, and the remaining capacity display unit is configured to supply power from one of the first cell unit and the second cell unit in both the non-connected state and the series-connected state of the first cell unit and the second cell unit.

[0008] According to another feature of the present invention, The remaining capacity display unit of the battery pack is configured to display the remaining battery capacity based on the voltage of one of the cell units receiving the power when the switch is operated, regardless of whether the first cell unit and the second cell unit are in a non-connected state or a series-connected state. The one of the cell units supplying power to the remaining capacity display unit is located on the ground side in the series-connected state, and includes a microcomputer connected to the one of the cell units supplying power to the remaining capacity display unit. The microcomputer has a normal mode in which it is always active, and a sleep mode in which it activates itself intermittently. Furthermore, the microcomputer outputs a discharge stop signal if an abnormality occurs in any of the plurality of battery cells.

[0009] According to yet another aspect of the present invention, The microcomputer of the battery pack performs lighting control to display the remaining battery capacity by the remaining capacity display unit based on the voltage of one of the first and second cell units. The remaining capacity display unit has a plurality of light-emitting diodes, each of which is connected to an input / output port of the microcomputer via a resistor connected in series. .Also, The battery pack is connected to an input / output port of the microcomputer and includes a temperature detection means for detecting the temperature of the battery pack. The battery pack further includes an adjustment unit that is connected to a cell unit other than the one cell unit that supplies power to the remaining capacity display unit and consumes the power of the other cell unit. The adjustment unit is controlled by the microcomputer. Effect of the Invention

[0010] According to the present invention, it is possible to provide a battery pack that can be attached to an electric device body and that can switch the connection state of a plurality of cell units. It is also possible to provide a battery pack that includes a control unit that can control discharging or charging of the battery pack while monitoring the state of the plurality of cell units. It is also possible to provide a battery pack that can stably control discharging or charging of the battery pack regardless of the connection state of the plurality of cell units. In addition, since the appropriate output voltage can be automatically obtained simply by attaching the battery pack to the electrical device itself, without relying on a mechanical switch mechanism to switch the output voltage, it is now possible to share the battery pack between electrical devices of different voltages. Furthermore, a protection circuit that monitors the state of the battery cells in each cell unit is provided, making it possible to adjust the balance of current consumption for each battery cell. Furthermore, an adjustment circuit for balancing the total power consumption of the protection circuit including the microcontroller of the lower cell unit and the power consumption of the protection circuit of the upper cell unit is provided on the upper cell unit side, thereby suppressing deterioration of the voltage balance between the cell units. Moreover, because the conditions for overload protection can be changed according to the type of electrical device, a battery pack that can efficiently utilize the capabilities of the electrical device can be realized. [Brief description of the drawings]

[0011] [Figure 1]1 is a diagram for explaining a state in which a battery pack according to the present invention is attached to an electric power tool; [Diagram 2] 2 is a perspective view showing the shape of a battery pack mounting portion 10 of the electric power tool main body 1 of FIG. [Diagram 3] 1 is a perspective view of a battery pack 100 according to an embodiment of the present invention. [Figure 4] 4 is a perspective view of the battery pack 100 in FIG. 3 with an upper case 110 removed. [Diagram 5] These figures show the individual shapes of the power terminals (161 and 171, 162 and 172, 167 and 177) in Figure 4, where (1) is an overall oblique view, (2) is an oblique view of the upper terminal part 200, and (3) is an oblique view of the lower terminal part 220. [Figure 6] 1A and 1B are perspective views showing the state in which the power terminal is connected to the power tool body, where (1) shows the state in which it is connected to the power tool body 30 of this embodiment, and (2) shows the state in which it is connected to a conventional power tool body 1. [Figure 7] 1A is a perspective view of a terminal portion 50 of an electric power tool body 30 of the present embodiment, and FIG. 1B is a diagram showing a connection state between the terminal portion 50 and a power terminal of a battery pack 100. FIG. [Figure 8] FIG. 1(1) is a perspective view of a terminal unit 20 of a conventional electric power tool body 1, and FIG. 1(2) is a diagram showing a connection state between the terminal unit 20 and a power terminal of a battery pack 100. FIG. [Figure 9] 5A and 5B are diagrams showing the shape of the signal terminal part 240 in FIG. 4 alone, in which (1) is a perspective view seen from the front left, and (2) is a perspective view seen from the lower right. [Figure 10] 13A and 13B are diagrams showing the state in which multiple signal terminal components 240 are fixed to a circuit board 150, where (1) is a diagram viewed from the front, (2) is a diagram of the signal terminal components 240 viewed from the left, and (3) is a bottom view viewed from below (1). [Figure 11] 5A and 5B are diagrams showing the shape of the connection terminal group in FIG. 4 and the board cover 180 arranged around it, where (1) is an oblique view, (2) is a front view, and (3) is a partially enlarged view of the board cover 180 in (2). [Figure 12]FIG. 4 is a perspective view of the upper case 110 of FIG. [Figure 13] FIG. 11 is a perspective view for explaining a method of applying resin to a circuit board 150. [Figure 14] 1A and 1B are diagrams showing a first modified example of the present embodiment, in which (1) is a perspective view of an upper terminal part 260 and a lower terminal part 280, (2) is a left side view, and (3) is a front view. [Figure 15] FIG. 13 is a diagram showing a second modified example of the present embodiment, and is a perspective view showing an upper terminal part 260 and a lower terminal part 280A. [Figure 16] 11 is an oblique view showing an upper terminal part 200A and a lower terminal part 220 relating to a third modified example of this embodiment, (1) showing the state in which they are connected to the body side terminals of the electric power tool body 30A, and (2) showing the state in which they are connected to the body side terminals of a conventional electric power tool body 1. [Figure 17] 11 is an oblique view showing an upper terminal part 200 and a lower terminal part 220A relating to a fourth modified example of this embodiment, (1) is a diagram showing the state in which they are connected to the body side terminals of the electric power tool body 30B, and (2) is a diagram showing the state in which they are connected to the body side terminals of a conventional electric power tool body 1. [Figure 18] 13 is a perspective view showing a connection state with a terminal portion of an electric power tool body according to a fifth modified example of the present embodiment. FIG. [Figure 19] FIG. 1 is a circuit diagram showing a state in which a battery pack 100 of the present embodiment is connected to a conventional power tool main body 1. [Figure 20] FIG. 1 is a circuit diagram of a battery pack 100 according to the present embodiment, showing a state in which the battery pack 100 is connected to an 18V electric power tool main body 1A equipped with a microcomputer. [Figure 21] FIG. 2 is a circuit diagram of the battery pack 100 of the present embodiment, showing the state in which it is connected to a 36V electric power tool main body 30. [Figure 22] 4 is a flowchart showing a control procedure of the battery pack 100. [Diagram 23] 1 is a diagram for explaining a specific circuit configuration of a remaining capacity display means 335 and an upper voltage detection circuit 322 of the battery pack 100. FIG. [Figure 24]24 is a detailed diagram of an input / output circuit to the microcomputer 351 in FIG. 23. [Diagram 25] 24 is a table showing the correspondence between the signal levels of the input / output ports IO0 to IO3 and the signal level of the input port AN1 in FIG. 23. [Figure 26] FIG. 11 is a circuit diagram of a battery pack 100A according to a second embodiment of the present invention, showing a state in which the battery pack 100A is connected to a conventional power tool main body 1. [Figure 27] FIG. 11 is a circuit diagram of a battery pack 100A according to a second embodiment of the present invention, showing a state in which the battery pack 100A is connected to an 18V electric power tool main body 1A equipped with a microcomputer. [Figure 28] FIG. 11 is an exploded perspective view showing a battery pack 400 according to a third embodiment of the present invention. [Figure 29] 29 is a partially enlarged view of the connection terminal of FIG. 28. [Diagram 30] 29 is an enlarged view of the terminal part of FIG. 28, in which (1) is a perspective view, and (2) is a diagram for explaining the contact length at the fitting portion. FIG. [Diagram 31] FIG. 13 is a perspective view showing a terminal part 500 according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same parts are given the same reference numerals, and repeated description will be omitted. In this specification, an electric tool operated by a battery pack will be described as an example of an electric device, and the front-rear, rear-left and right directions of the main body of the electric tool will be described as directions shown in FIG. 2, and the front-rear, rear-left and right directions and up-down directions when the battery pack is viewed alone will be described as directions shown in FIG. 3 based on the mounting direction of the battery pack. For convenience of explanation, the mounting direction of the battery pack will be described as directions based on a situation in which the battery pack is moved without moving the main body of the electric tool.

[0013] FIG. 1 is a diagram for explaining the mounting state of the battery pack according to the present embodiment on the electric tool. The electric tool, which is one form of electrical equipment, has a battery pack and drives a tip tool or a work device using a rotational driving force of a motor. There are various types of electric tools, but the electric tool main body 1, 30 shown in FIG. 1 is all called an impact tool. The electric tool main body 1, 30 is a tool that performs a tightening operation by applying a rotational force or an axial impact force to a tip tool such as a bit or a socket wrench (not shown). These electric tool main bodies 1, 30 include a housing 2, 32 that is an outer frame that forms the outer shape, and a handle section 3, 33 is formed on the housing 2, 32. A trigger-shaped operation switch 4, 34 is provided in a part of the handle section 3, 33 near where the index finger of the operator touches when the tool is held, and a battery pack mounting section 10, 40 for mounting a battery pack 15, 100 is formed below the handle section 3, 33.

[0014] 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, and can be attached to the battery pack attachment section 10 of an electrical device (power tool body 1) that supports 18V, as shown by the combination of arrow a. The battery pack 15 contains only one cell unit formed by connecting five cells of a lithium-ion battery with a rated voltage of 3.6V in series, or contains two such cell units that are connected in parallel. The voltage of 18V is sometimes referred to as low voltage here, since it is a relatively low voltage. Similarly, the power tool body 1 or electrical device body with a rated voltage of 18V may be referred to as a low-voltage power tool body or a low-voltage electrical device body, respectively. Similarly, the battery pack 15 with a nominal voltage of 18V may be referred to as a low-voltage battery pack.

[0015] The power tool main body 30 is an electric device main body with a rated voltage of 36V, and the battery pack 100 capable of outputting 36V is attached to the battery pack attachment section 40 as shown by the arrow b1. The voltage of 36V is sometimes referred to as high voltage here, meaning that it is a relatively high voltage. Similarly, the power tool main body 30 or the electric device main body with a rated voltage of 36V may be called a high-voltage power tool main body or a high-voltage electric device main body, respectively. The battery pack 100 contains two sets of cell units in which five cells of a lithium-ion battery rated at 3.6V are connected in series, and by changing the connection method of the two sets of cell units, it is possible to switch between 18V output and 36V output. In this embodiment, the battery pack 100 is configured to support two voltages and is capable of outputting low and high voltages, so that the battery pack 100 can be attached to the power tool main body 1 compatible with 18V as shown by the arrow b2, and can also be attached to the power tool main body 30 compatible with 36V as shown by the arrow b1. The battery pack 100 capable of outputting low and high voltages in this way is sometimes referred to herein as a variable voltage battery pack. In order to mount the battery pack 100 on the power tool main body 1, 30 of different voltages as indicated by arrows b1, b2, it is important that the rails and terminals of the battery pack mounting parts 10, 40 have approximately the same shape and that the output voltage of the battery pack 100 is switchable. At this time, it is important to ensure that the output voltage of the battery pack 100 corresponds to the rated voltage of the electrical device main body or power tool main body to which it is mounted, to prevent voltage setting errors.

[0016] FIG. 2 is a perspective view showing the shape of the battery pack attachment section 10 of the electric power tool main body 1. The electric power tool main body 1 shown here is an impact driver, and is provided with a handle section extending downward from the body section of the housing 2, and the battery pack attachment section 10 is formed below the handle section. The handle section is provided with a trigger switch 4 (operation switch). An anvil (not shown) serving as an output shaft is provided on the front side of the housing 2, and a tip tool holder 8 for attaching a tip tool 9 is provided at the tip of the anvil. Here, a Phillips screwdriver bit is attached as the tip tool 9. Not only in electric power tools, but in general electrical equipment using a battery pack, the battery pack attachment section 10 is formed to correspond to the shape of the battery pack to be attached, and is configured so that a battery pack that does not fit the battery pack attachment section 10 cannot be attached. Rail grooves 11a and 11b extending in parallel in the front-rear direction are formed on the inner wall sections on both the left and right sides of the battery pack attachment section 10, and a terminal section 20 is provided between them. The terminal section 20 is manufactured by integral molding of a non-conductive material such as synthetic resin, and multiple 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 terminal section 20 is formed with a vertical surface 20a, which serves as an abutment surface in the mounting direction (front-rear direction), and a horizontal surface 20b, which is adjacent to and faces an upper surface 115 (described later in FIG. 3) when the battery pack 100 is mounted. A curved portion 12 is formed on the front side of the horizontal surface 20b, which abuts against a raised portion 132 (described later in FIG. 3) of the battery pack 100, and a protrusion 14 is formed near the center of the curved portion 12. The protrusion 14 also serves as a boss for screwing the housing of the power tool main body 1, which is formed by dividing it into two parts in the left-right direction, and also serves as a stopper that limits the relative movement of the battery pack 100 in the mounting direction.

[0017] FIG. 3 is a perspective view of a battery pack 100 according to an embodiment of the present invention. The battery pack 100 can be attached to and detached from the battery pack attachment section 10, 40 (see FIG. 1), and automatically switches between low voltage (18V in this case) and high voltage (36V in this case) output depending on the shape of the terminal on the power tool main body 1 or 30 side. In order to provide compatibility with a conventional battery pack 15 (see FIG. 1) for a rated voltage of 18V, the shape of the attachment section of the battery pack 100 is the same as that of the conventional battery pack 15. The housing of the battery pack 100 is formed by a lower case 101 and an upper case 110 that can be separated in the vertical direction. The lower case 101 and the upper case 110 are made of a material that does not conduct electricity, such as synthetic resin, and are fixed to each other by four screws. The upper case 110 is formed with a mounting mechanism having two rails 138a, 138b for mounting to the battery pack attachment section 10. The rails 138a, 138b are formed to extend in a direction parallel to the mounting direction of the battery pack 100 and to protrude to the left and right side surfaces of the upper case 110. The front ends of the rails 138a, 138b are open ends, and the rear ends are closed ends connected to the front wall surface of the raised portion 132. The rails 138a, 138b are formed in shapes corresponding to the rail grooves 11a, 11b (see FIG. 2) formed in the battery pack mounting portion 10 of the electric power tool main body 1. With the rails 138a, 138b fitted into the rail grooves 11a, 11b, the battery pack 100 is fixed to the electric power tool main body 1 or 30 by being engaged with the locking portions 142a (the locking portion on the right side and not visible in FIG. 3) and 142b which serve as pawls of a latch. When removing the battery pack 100 from the power tool body 1 or 30, the latches 141 on both the left and right sides are pressed, causing the locking portions 142a, 142b to move inward and release the locked state, and in this state the battery pack 100 is moved in the opposite direction to the attachment direction. The upper case 110 and the lower case 101 are an example of the "case" in this invention.

[0018] A flat lower surface 111 is formed on the front side of the upper case 110, and an upper surface 115 is formed near the center, which is higher than the lower surface 111. 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 which is a vertical surface. The portion forward of the step portion 114 to the upper surface 115 forms a slot group arrangement area 120. In the slot group arrangement area 120, a plurality of slots 121 to 128 are formed which extend rearward from the front step portion 114. The slots 121 to 128 are cut out to have a predetermined length in the battery pack attachment direction, and a plurality of connection terminals (described later in FIG. 4) which can be fitted to device side terminals of the power tool main body 1, 30 or an external charging device (not shown) are arranged inside the cut out portion. The slots 121-128 have notches formed not only on the upper surface parallel to the mounting direction but also on the vertical surface so that the terminals on the power tool main body side can be inserted from the lower surface 111. In addition, between the lower side of the slots 121-128 and the lower surface 111, an opening 113 is formed which opens continuously in the horizontal direction.

[0019] Of the slots 121-128, the slot 121 on the side closer to the rail 138a on the right side of the battery pack 100 is an insertion port for a positive electrode terminal for charging (C+ terminal), and the slot 122 is an insertion port for a positive electrode terminal for discharging (+ terminal). The slot 127 on the side closer to the rail 138b on the left side of the battery pack 100 is an insertion port for a negative electrode terminal (- terminal). In the battery pack 100, the positive and negative sides of the power terminals are usually arranged so as to be sufficiently separated from each other, and the positive terminal is provided at a position sufficiently separated on the right side as viewed from a vertical imaginary plane located at the center of the left and right, and the negative terminal is provided at a position sufficiently separated on the left side. Between the positive and negative terminals, a plurality of signal terminals for transmitting signals to the battery pack 100 and the power tool main body 1, 30 or an external charging device (not shown) are arranged, and here, four slots 123-126 for the signal terminals are provided between the power terminal groups. Slot 123 is a spare terminal insertion port, and in this embodiment, no terminal is provided. Slot 124 is an insertion port for a T terminal for outputting a signal serving as identification information for battery pack 100 to the power tool main body or a charging device. Slot 125 is an insertion port for a V terminal for inputting a control signal from an external charging device (not shown). Slot 126 is an insertion port for an LS terminal for outputting battery temperature information from a thermistor (temperature-sensing element) (not shown) provided in contact with the cell. To the left of slot 127, which serves as an insertion port for the negative terminal (- terminal), there is further provided a slot 128 for an LD terminal for outputting an abnormal stop signal from a battery protection circuit (described later) included in battery pack 100.

[0020] A protruding portion 132 is formed on the rear side of the upper surface 115. The external shape of the protruding portion 132 is shaped to protrude upward from the upper surface 115, and a recessed stopper portion 131 is formed near the center of the protruding portion 132. The stopper portion 131 serves as an abutting surface for the protrusion portion 14 (see FIG. 2) when the battery pack 100 is attached to the battery pack attachment portion 10, and when the protrusion portion 14 on the electric power tool main body 1 side is inserted until it abuts against the stopper portion 131, a plurality of terminals (device side terminals) arranged on the electric power tool main body 1 and a plurality of connection terminals (described later in FIG. 4) arranged on the battery pack 100 come into contact with each other and are in a conductive state. Furthermore, locking portions 142a (the locking portion on the right side and not visible in FIG. 3) and 142b of latch 141 of battery pack 100 jump outward vertically below rails 138a and 138b due to the action of a spring and engage with recesses (not shown) formed in rail grooves 11a and 11b of the power tool body 1, thereby preventing battery pack 100 from falling off. A slit 134 is provided on the inside of stopper portion 131 as a cooling air intake port connected to the inside of battery pack 100. Furthermore, when battery pack 100 is attached to power tool body 1, slit 134 is covered and closed so as not to be visible from the outside. Slit 134 is an air window used to force cooling air into the inside of battery pack 100 when battery pack 100 is connected to a charging device (not shown) for charging, and the cooling air taken into battery pack 100 is exhausted to the outside through slit 104, which serves as an exhaust air window, provided in the front wall of lower case 101.

[0021] FIG. 4 is a perspective view of the battery pack 100 of FIG. 3 with the upper case 110 removed. Ten battery cells are housed in the internal space of the lower case 101. Two screw holes 103a and 103b are formed in the front side wall surface of the lower case 101 for screwing the upper case 110, and screws (not shown) are inserted through the screw holes 103a and 103b from bottom to top. Although not visible in this figure, two screw holes are also formed in the rear side wall surface of the lower case 101. A plurality of battery cells (not shown) are fixed by a separator 145 in a state where they are stacked in two stages of five cells each. The separator 145 is made of synthetic resin and is formed so that only the left and right sides, which are both ends of the battery cells, are open. In the separator 145, the axes of the battery cells are stacked so that they are parallel to each other, and the orientations of adjacent cells are alternately reversed, and the positive and negative terminals of adjacent battery cells are connected by metal connection tabs (not shown) to connect the five battery cells in series. Here, five battery cells connected in series installed on the upper side form an upper cell unit 146 (described later in FIG. 6), and five battery cells connected in series installed on the lower side form a lower cell unit 147 (described later in FIG. 6). Note that the upper and lower sides of the cell unit do not refer to whether the battery cells are in the upper or lower side in the lower case 101, but rather, when two cell units are connected in series, the cell unit located on the ground side is called the "lower cell unit", and the cell unit located on the higher voltage side when connected in series is called the "upper cell unit". The upper cell unit 146 is an example of the "first cell unit" in the present invention, and the lower cell unit 147 is an example of the "second cell unit" in the present invention. The state in which the upper cell unit 146 and the lower cell unit 147 are connected in series is an example of the "series connection state" in the present invention.

[0022] The battery cells are lithium-ion battery cells (not shown) called 18650 size, which have a diameter of 18 mm and a length of 65 mm and can be charged and discharged multiple times. In this embodiment, in order to make it possible to switch the output voltage from the battery pack 100, the form of a series connection voltage (high voltage side output) of multiple cell units and a parallel connection voltage (low voltage side output) can be selected. Therefore, according to the idea of ​​this embodiment, the number of cell units is arbitrary as long as the number of cells included in each cell unit is equal. However, the number of cell units is an even number such as two or four. The battery cells used are not limited to 18650 size, but may be so-called 21700 size battery cells or battery cells of other sizes. The shape of the battery cells is not limited to cylindrical, but may be rectangular, laminated, or other shapes. The type of battery cells is not limited to lithium-ion batteries, but any type of secondary battery such as nickel-metal hydride battery cells, lithium-ion polymer battery cells, and nickel-cadmium battery cells may be used. Two electrodes are provided at both ends of the length of the battery cell. Of the two electrodes, one is a positive electrode and the other is a negative electrode, but the locations at which the electrodes are provided are not limited to only the two ends, and any electrode arrangement may be used as long as a cell unit can be easily formed within the battery pack.

[0023] A circuit board 150 is disposed on the upper side of the separator 145 that holds the battery cells. The circuit board 150 has a plurality of connection terminals (161, 162, 164-168, 171, 172, 177) fixed by soldering, and electrically connects the circuit pattern to the connection terminals. The circuit board 150 further includes various electronic elements (not shown here) such as a battery protection IC, a microcomputer, a PTC thermistor, a resistor, a capacitor, a fuse, and a light-emitting diode. The circuit board 150 is fixed so as to extend horizontally on the upper side of the separator 145 made of a non-conductive material such as synthetic resin. The material of the circuit board 150 is called a printed circuit board, which is a board impregnated with a resin that is insulating against the material, and on which pattern wiring is printed with a conductor such as copper foil, and a single-layer board, double-sided board, or multilayer board can be used. In this embodiment, a double-sided board is used to provide the circuit board 150 with an upper surface (the surface that is the upper surface as seen from FIG. 4) and a lower surface (the back surface). A plurality of connection terminals (161, 162, 164 to 168, 171, 172, 177) are arranged slightly forward from the center in the front-rear direction of the circuit board 150. Here, the plurality of connection terminals are arranged substantially side by side in the horizontal direction.

[0024] The connection terminals are as shown by markings on the upper surface of the upper case 110 as shown in FIG. 3, and are arranged in a line from the right side to the left side of the circuit board 150 in the order of C+ terminal (161, 171: positive terminal for charging), + terminal (162, 172: positive terminal for discharging), T terminal 164, V terminal 165, LS terminal 166, - terminal (167, 177: negative terminal), and LD terminal 168. Here, the connection terminal for the power supply line from the battery pack, i.e., the power terminal, is composed of two separated terminal parts. That is, the C+ terminal (positive terminal for charging) is composed of the upper positive terminal 161 and the lower positive terminal 171, and these positive terminal pairs (161, 171) are arranged at locations corresponding to a single slot 121. The arm set of the upper positive electrode terminal 161 is disposed above the inner portion of the slot 121, and the arm set of the lower positive electrode terminal 171 is disposed below the arm set of the upper positive electrode terminal 161. Similarly, the + terminal (positive electrode terminal for discharge) marked on the upper case 110 is composed of the upper positive electrode terminal 162 and the lower positive electrode terminal 172, and this positive electrode terminal pair (162, 172) is disposed at a location corresponding to the single slot 122. The arm set of the upper positive electrode terminal 162 is disposed above the slot 122 portion, and the arm set of the lower positive electrode terminal 172 is disposed below the arm set of the upper positive electrode terminal 162. The - terminal (negative electrode terminal) marked on the upper case 110 is composed of the upper negative electrode terminal 167 and the lower negative electrode terminal 177, and this negative electrode terminal pair (167, 177) is disposed at a location corresponding to the single slot 127. The arm set of the upper negative electrode terminal 167 is disposed above the slot 127 , and the arm set of the lower negative electrode terminal 177 is disposed below the arm set of the upper negative electrode terminal 167 .

[0025] The connection terminals (161, 162, 164 to 168) are disposed at positions corresponding to the slots 121 to 128 shown in Fig. 3. Therefore, they are disposed so that the fitting portions of the connection terminals open upward and forward from the circuit board 150. However, the portion between the upper positive terminal 162 and the T terminal 164 is an unused empty space in the battery pack 100 of this embodiment, similar to the conventional battery pack 1 (see Fig. 1).

[0026] The positive electrode terminal pair (161, 171) for charging is offset forward from the adjacent positive electrode terminal pair (162, 172) for discharging. This is due to space restrictions, and is to avoid the movement range of a latch mechanism (not shown) immediately behind the positive electrode terminal pair (161, 171). Therefore, if there is no space restriction, the positive electrode terminal pair (161, 171) should be arranged so that the front ends of the positive electrode terminal pair (162, 172) and the negative electrode terminal pair (167, 177) are aligned.

[0027] The positive terminals (161, 162, 171, 172) and the negative terminals (167, 177) are arranged at positions far apart in the left-right direction, and three signal terminals (T terminal 164, V terminal 165, LS terminal 166) are provided between them. In this embodiment, a part for the signal terminal is provided with two sets of arms extending in the horizontal direction, one set on the upper left and right and one set on the lower left and right, and the detailed shape will be described later in FIG. 9. For the signal terminals (164 to 166, 168), it is possible to use a signal terminal part having one arm in the vertical direction as is, as has been conventionally used. However, in this embodiment, in order to make the fitting state of the positive terminals (161, 162, 171, 172) and the negative terminals (167, 177) equivalent to that of the device side terminals, a signal terminal part having two arms on the upper and lower sides (described later in FIG. 9) is used on the signal terminal side.

[0028] An additional signal terminal, i.e., an LD terminal 168, is provided to the left of the negative terminal pair (167, 177). The LD terminal 168 is also formed to have two pairs of arms, upper and lower. However, the LD terminal 168 is different in size from the other signal terminals (T terminal 164, V terminal 165, LS terminal 166). This is due to space constraints, and since a latch mechanism (not shown) reaches immediately behind the LD terminal 168, the LD terminal 168 is formed smaller than the other signal terminals to avoid this. All the signal terminals (164 to 166, 168) are fixed by soldering on the back side, with their legs penetrating through mounting holes 151 formed in the circuit board 150 from the front side to the back side. In this embodiment, the method of fixing the three signal terminals (164 to 166) is also characterized, and the details will be described later with reference to Figures 9 and 10. As described above, after electronic elements (not shown) are mounted on circuit board 150 and a plurality of connection terminals are fixed by soldering, circuit board 150 is fixed to separator 145 by screws, adhesive, or the like.

[0029] Four LEDs (not shown) are provided near the rear edge of the circuit board 150, and rectangular parallelepiped prisms 191-194 that are elongated in the vertical direction are provided above the LEDs. The prisms 191-194 are arranged so that their bottom faces face the lighting surfaces of LEDs (light-emitting diodes, not shown) that irradiate light upward, and their obliquely cut upper faces are provided so that they are exposed to the outside through slits (not shown) formed in the upper case 110. The prisms 191-194 are provided to diffuse light and irradiate it to the outside of the upper case 110. The four LEDs (not shown) are used to display the remaining charge of the battery pack 100, and when an operator presses the switch 190, the number of LEDs corresponding to the voltage of the battery cells are lit for a certain period of time (details will be described later with reference to Figs. 24 and 25). An operating lever (not shown) for operating the switch 190 is provided on the outer surface of the upper case 110 that can be operated by an operator. The lower case 101 is in the shape of a substantially rectangular parallelepiped with an open top, and is composed of a bottom surface, a front wall 101a, a rear wall 101b, a right side wall 101c, and a left side wall 101d that extend vertically relative to the bottom surface. A slit 104 is provided in the approximate center of the front wall 101a. The slit 104 is used as an exhaust port for exhausting cooling air sent from the charging device into the internal space of the battery pack 100 when charging with the charging device.

[0030] Next, the shapes of the parts (200, 220) used in the power terminal will be described with reference to FIG. 5. FIG. 5(1) is a perspective view showing the upper terminal part 200 and the lower terminal part 220 as individual parts. The upper terminal part 200 is a common part used for the upper positive terminals 161, 162 and the upper negative terminal 167, and the lower terminal part 220 is a common part used for the lower positive terminals 171, 172 and the lower negative terminal 177. The upper terminal part 200 and the lower terminal part 220 are formed by cutting out a flat plate made of conductive metal by press processing and then bending it into a U-shape. The upper terminal part 200 is bent so that the surface that becomes the bottom of the U-shape, i.e., the bridge part 202, is on the upper side, and the lower terminal part 220 is bent so that the bridge part 222 is on the rear side. The reason why the bridge parts 202 and 222 formed by bending in a U-shape are arranged to intersect at a nearly right angle is that the area of ​​the side wall surface of the front bridge part 222 cannot be sufficiently secured in the front-rear direction, so that the size of the bridge part would be small if it were arranged on the upper side. In the lower terminal part 220 of this embodiment, the bridge part 222 is arranged in the vertical plane direction, so that the length in the front-rear direction required for arrangement can be shortened, and the size of the bridge part, especially the length in the up-down direction, can be sufficiently secured, so that the rigidity of the lower terminal part 220 can be increased. On the other hand, in the upper terminal part 200, long arms 205 and 206 can be formed so as to straddle the lower terminal part 220, and the bridge part 202 is arranged to have a surface extending in the same direction as the front-rear direction in which the arms 205 and 206 extend, so that the mounting rigidity of the arms 205 and 206 can be increased.

[0031] The upper terminal part 200 has a right side surface 203 and a left side surface 204 formed in parallel by bending them in a U-shape, and a bridge part 202 that connects them and serves as the upper surface. On the front sides of the right side surface 203 and the left side surface 204, arm parts 205 and 206 are provided from both the left and right sides toward the inside to sandwich the device side terminal. The front edge part of the left side surface 204 extends in a straight line in the vertical direction from the lower side to a position close to the upper end, and is formed so as to extend forward from the vicinity of the arrow 204d close to the upper end in a curve with a large radius of curvature. The shape of the right side surface 203 is formed in plane symmetry with the left side surface 204. The arm part 205 is arranged to extend forward from the upper front edge of the right side surface 203, and the arm part 206 is arranged to extend forward from the upper front edge of the left side surface 204. In this way, the arms 205 and 206 are formed so as to extend forward from the upper portion of the front edge of the base 201, that is, in a direction parallel to the mounting direction of the battery pack 100. The arms 205 and 206 face each other when viewed in the left-right direction, and are pressed so as to approach the minimum interval portion, that is, the position where the fitting portion that fits with the device connection terminal almost comes into contact, thereby giving them springiness. Here, the press working is a plastic processing performed using a press machine, in which a material such as a sheet metal is pressed against a die with high pressure, and shearing processing such as cutting, punching, and drilling is performed, and further bending and drawing are performed as necessary to shear and form the required shape. In this embodiment, the upper terminal part 200 and the lower terminal part 220 are formed of a flat plate having a thickness of, for example, about 0.5 to 0.8 mm. This provides the positive terminals 161, 162, 171, 172 and the negative terminals 167, 177 with high mechanical strength, and increases the fitting pressure when fitting with the device side terminals. After the press working, heat treatment, plating treatment, etc. may be performed.

[0032] The lower terminal part 220 is manufactured in the same manner, and has a base part 221 consisting of a right side surface 223 and a left side surface 224 formed in parallel by bending them in a U-shape, and a bridge part 222 connecting them, and arms 225 and 226 are formed from the elongated upper part of the right side surface 223 and the left side surface 224 to the front side. The arms 225 and 226 are shaped to sandwich the device side terminal from both the left and right sides toward the inside. The distance S between the upper end position of the upper arm set (205, 206) and the lower end position of the lower arm set (225, 226) is configured to be approximately equal to the width of the power terminal provided on a conventional 18V battery pack. Meanwhile, the upper arm set (205, 206) and the lower arm set (225, 226) are arranged to be spaced apart from each other by a predetermined distance S1 in the vertical direction. A notch 231 is formed by cutting out a large area from the front side below the lower arm set (225, 226). The rear side of the lower terminal part 220 is aligned in the front-rear direction and fixed to the right side surface 203 and the left side surface 204 of the upper terminal part 200 with a predetermined gap 211 between them so as not to come into contact with each other.

[0033] 5(2) is a perspective view of the upper terminal part 200 alone, in which the area of ​​the bridge part 202 and the leg parts 207 and 208 are hatched to clarify their range. The base part 201 referred to in this specification is the part exposed upward from the surface of the circuit board 150 to which it is attached, excluding the arm parts 205 and 206. The base part 201 of the upper terminal part 200 is composed of a right side surface 203, a left side surface 204, and the bridge part 202. The leg parts 207 and 208 are connected below the lower edge part of the base part 201. The legs 207 and 208 are inserted into mounting holes (through holes) of the circuit board 150, and the legs 207 and 208 are protruded from the mounting surface (front surface) of the circuit board 150 to the surface (back surface) opposite the mounting surface, and the legs 207 and 208 are soldered to the circuit board 150 on the back surface. The arms 205 and 206 are electrically connected to the battery cells and electronic elements mounted on the circuit board 150 by soldering. Here, the height H1 of the legs 207 and 208 is formed to be greater than the thickness of the circuit board 150 but less than twice as large. In addition, a protrusion 204b protruding rearward is formed on the lower part of the rear edge of the left side surface 204. Although not visible in FIG. 5, a similar protrusion is also formed on the lower part of the rear edge of the right side surface 203. At the front side of the lower portions of the right side surface 203 and the left side surface 204, a portion extending in a horizontally convex shape is formed, and the convex portion is bent inward to form bent portions 203a, 204a. At the upper and lower sides of the bent portions of the bent portions 203a, 204a, cutout portions 203c, 204c, 207a, 208a are formed to facilitate the bending process. The bent portions 203a, 204a and the convex portions 203b, 204b are formed to contact the upper surface of the circuit board 150 in the vicinity of the mounting hole, and to position the upper terminal component 200 in the up-down direction.

[0034] The base portion 201 is in an inverted, generally L-shaped shape in side view. The rear portions of the arms 205 and 206 are formed with flat portions 205a and 206a, with the right side surface 203 and the left side surface 204 extending from the rear connection portion toward the front in the same plane. The flat portions 205a and 206a are parallel to each other with a constant left-right distance between them. In front of the flat portions 205a and 206a, bent portions 205b and 206b are formed, which are bent inward in the left-right direction. In front of the bent portions 205b and 206b, flat portions 205c and 206c are formed again. The opposing flat portions 205c and 206c are tapered such that the distance between them is wide on the rear side and gradually narrows toward the front side, and each of them is a surface extending in the vertical direction. The tip portions of the flat portions 205c, 206c are bent to expand outward with a larger radius of curvature R1 to form the fitting portions 205d, 206d. The inner curved portions of the fitting portions 205d, 206d come into contact with the terminals of the electric power tool main body 1, 30, so that the upper terminal part 200 is electrically connected to the connection terminals on the electric power tool main body 1, 30 side. The inner sides of the fitting portions 205d, 206d are shaped to have a small gap 209 when the battery pack 100 is removed from the electric power tool main body 1, 30. The front sides of the fitting portions 205d, 206d are connected to guide portions 205e, 206e that are formed so that the gap increases rapidly toward the front, and guide the terminals on the electric power tool main body 1, 30 side. The inner surfaces of the guide portions 205e, 206e are flat here, but may be curved. The height in the vertical direction is constant from the bent portion 205b to the guide portion 205e, and from the bent portion 206b to the guide portion 206e. On the other hand, the flat portions 205a, 206a are formed with the downward notches 205f, 206f so that the height decreases toward the rear side. The notches 205f, 206f are formed for the manufacturing reason of making it easier to bend the arm portions 205, 206 during press processing, and for adjusting the clamping load (or fitting pressure) at the pair of fitting portions 205d, 206d. By forming it in the above manner, the upper terminal part 200 that is excellent in durability and easy to use has been realized.Incidentally, it is preferable that the height direction of the fitting portions 205d, 206d of the arm portions 205, 206 be as large as possible, but the vertical heights of the bent portions 205b, 206b, the flat portions 205c, 206c, and the guide portions 205e, 206e do not necessarily need to be constant, and may be formed in a shape that changes in the forward and backward directions.

[0035] FIG. 5(3) is a perspective view of the lower terminal part 220 alone, and here too, the area of ​​the bridge part 222 and the leg parts 227 and 228 are hatched to clarify the range. As can be seen in this figure, the direction of bending the lower terminal part 220 into a U-shape is different from that of the upper terminal part 200. Here, the base part 221 is substantially L-shaped when viewed from the side, and the arm parts 225 and 226 are connected forward of the upper front edges of the right side surface 223 and the left side surface 224. The arm parts 225 and 226 near the connection part with the base part 221 are formed with flat parts 225a and 226a that are on the same plane as the right side surface 223 and the left side surface, and the opposing surfaces are parallel. In front of the flat parts 225a and 226a, bent parts 225b and 226b are formed that are bent inward when viewed in the left-right direction. Planar portions 225c, 226c are formed again on the front side of the bent portions 225b, 226b. The opposing planar portions 225c and 226c have a tapered shape with a wide gap on the rear side and gradually narrowing toward the front side. The tip portions of the planar portions 225c, 226c are bent with a large radius of curvature to form fitting portions 225d, 226d. The inner curved surfaces of the fitting portions 225d, 226d come into contact with the terminals of the electric power tool main body 1, 30, thereby establishing electrical conduction. The insides of the fitting portions 225d, 226d are shaped to have a small gap when the battery pack 100 is removed from the electric power tool main body 1, 30. The front side of the fitting portions 225d, 226d is formed so that the gap rapidly widens toward the front, and guide portions 225e, 226e for guiding the terminals of the electric power tool main body 1, 30 are formed. The inner surfaces of the guide portions 225e and 226e may be flat or curved. The vertical height is constant from the flat portion 225a to the guide portion 225e, and from the flat portion 226a to the guide portion 226e. However, similar to the arm portions 205 and 206 of the upper terminal part 200, the vertical height may be varied except for the fitting portions 225d and 226d. By forming the lower terminal part 220 as described above, this embodiment realizes a lower terminal part 220 that is durable and easy to use.

[0036] The lower side of the arms 225 and 226 of the lower terminal component 220 has a cutout 231 (see FIG. 5(1)) cut in a U-shape from the front side to the rear side in a side view. The cutout 231 is formed because a board cover 180 (described later in FIG. 11) for separating the upper terminal component 200 and the lower terminal component 220 is provided in this portion. The legs 227 and 228 are connected to the lower side of the base 221. The legs 227 and 228 are inserted into mounting holes in the circuit board 150, and the legs 227 and 228 are caused to protrude from the mounting surface (front surface) of the circuit board 150 to the opposite surface (back surface), and the protruding portions are soldered. In addition, an electrical connection state is established from the arms 225 and 226 to the battery cells, electronic elements, etc. mounted on the circuit board 150 by soldering. Here, the pair of legs 227, 228 is wired independently without being short-circuited with the pair of legs 207, 208 of the upper terminal part 200. The dimensions and shape of legs 227, 228 are substantially the same as those of legs 207, 208, and bent portions 223a, 224a are formed on the front side. Cutout portions 223c, 224c, 227a, 228a are formed above and below the bent portions of bent portions 223a, 224a, but the cutout portions are formed in order to improve the accuracy of bending during press working, and therefore the cutout portions are not necessarily required.

[0037] Next, the shape of the terminal section 20 on the electric power tool main body 1, 30 side and the connection state with the connection terminal of the battery pack 100 when the battery pack 100 is attached to the electric power tool main body 1, 30 will be described with reference to FIG. 6. Here, the positive terminal (upper positive terminal 162, lower positive terminal 172) and the negative terminal (upper negative terminal 167 and lower negative terminal 177) for discharging are shown among the connection terminals of the battery pack 100. The terminal section 20, 50 of the electric power tool main body 1, 30 is further provided with LD terminals 28, 58, but these are not shown here. FIG. 6(1) is a diagram showing the state in which the battery pack 100 is attached to the electric power tool main body 30 for 36V. As described 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. Here, the terminal portions 52a, 57a of the positive input terminal 52 and the negative input terminal 57 are smaller than the terminal portion 20 of the conventional electric power tool main body 1. In other words, the terminal portions are formed with a small vertical width so as to contact only the upper positive terminal 162 and the upper negative terminal 167 arranged on the upper side. The positive output terminal of the upper cell unit 146 is connected to the upper positive terminal 162, and the negative output terminal is connected to the lower negative terminal 177. On the other hand, the positive output terminal of the lower cell unit 147 is connected to the lower positive terminal 172, and the negative output terminal is connected to the upper negative terminal 167. That is, two sets of positive and negative terminals are provided independently, and one set of terminals (upper positive terminal 162 and lower negative terminal 177) crossing in the left-right direction and up-down direction is connected to the upper cell unit 146, and the other set of terminals (lower positive terminal 172 and upper negative terminal 167) is connected to the lower cell unit 147. Since the upper positive terminal 162 and the lower positive terminal 172 are not electrically connected, they are in an electrically independent state when the battery pack 100 is not attached to the electric device body (when the battery pack 100 is detached). Similarly, since the upper negative terminal 167 and the lower negative terminal 177 are not electrically connected inside the battery pack 100, they are in an electrically independent state when the battery pack 100 is not attached to the electric device body (when the battery pack 100 is detached).The state in which the upper cell unit 146 and the lower cell unit 147 are electrically independent from each other is an example of the "disconnected state" in the present invention.

[0038] As shown in FIG. 6(1), the terminal section of the power tool main body 30 rated at 36V is provided with a positive input terminal 52 and a negative input terminal 57 for receiving power. When mounted, the positive input terminal 52 is positioned so that it fits only with the upper positive terminal 162, and the negative input terminal 57 is positioned so that it fits only with the upper negative terminal 167. Meanwhile, the terminal section of the power tool main body 30 is further provided with a shorting bar 59 that connects the lower positive terminal 172 and the lower negative terminal 177 so as to short them out. The shorting bar 59 is a short circuiter made of a metal conductive member, and one end of the metal member bent into a U-shape becomes a terminal portion 59b that fits with the lower positive terminal 172, and the other end becomes a terminal portion 59c that fits with the lower negative terminal 177. The terminal portion 59b and the terminal portion 59c are connected at a connection portion 59a. The short bar 59 is fixed by being cast into a synthetic resin base 51 (described later in FIG. 7) together with other device side terminals such as the positive input terminal 52 and the negative input terminal 57. The short bar 59 is used only to short-circuit the lower positive terminal 172 and the lower negative terminal 177, and therefore does not need to be wired to a control circuit or the like of the power tool body.

[0039] The positive input terminal 52 is formed by a terminal portion 52a formed in a flat plate shape to be fitted with the upper positive terminal 162, a wiring portion 52c for soldering a lead wire for connecting to the circuit board side of the power tool main body 30, and a connecting portion 52b for connecting between the terminal portion 52a and the wiring portion 52c and being cast into the synthetic resin base 51. Here, the position of the wiring portion 52c is arranged so as to be shifted inward compared to the left-right position of the terminal portion 52a, but this is for adjusting the spacing of the wiring portion 52c and for the connecting portion 52b to be stably held by the base 51 by casting. Furthermore, the left and right corners on the front side of the terminal portion 52a are beveled obliquely so that the terminal portion 52a can easily fit between the arm portions 162a and 162b. The negative input terminal 57 can be a common part with the positive input terminal 52, and can be used as both the negative input terminal 57 and the positive input terminal 52 by rotating it 180 degrees around the vertical axis. Therefore, the negative input terminal 57 is also formed by a terminal portion 57a, a wiring portion 57c, and a connecting portion 57b that connects them. The front corner of the terminal portion 57a ​​(the rear corner when this part is used as the positive input terminal 52) is also beveled to make it easier for the terminal portion 57a ​​to fit between the arm portions 167a and 167b.

[0040] In Fig. 6 (1), when the battery pack 100 is attached, the battery pack 100 is moved relative to the power tool body 30 in the insertion direction, and the positive input terminal 52 and the terminal portion 59b are inserted into the power tool body 30 through the same slot 122 (see Fig. 3) and are fitted into the upper positive terminal 162 and the lower positive terminal 172, respectively. At this time, the positive input terminal 52 is pressed into between the arm portions 162a and 162b of the upper positive terminal 162 so as to push apart the fitting portions of the upper positive terminal 162. In addition, the negative input terminal 57 and the terminal portion 59c are inserted into the power tool body 30 through the same slot 127 (see Fig. 3) and are fitted into the upper negative terminal 167 and the lower negative terminal 177, respectively. At this time, the negative input terminal 57 is press-fitted between the arms 167a and 167b of the upper negative terminal 167 so as to push and spread apart the fitting portions of the upper negative terminal 167. Furthermore, the terminals 59b and 59c of the short bar 59 are press-fitted between the arms 172a and 172b and between the arms 177a and 177b of the lower positive terminal 172 and the lower negative terminal 177. In addition, as shown in FIG. 7(1), the front corners of the terminals 52a, 54a to 58a, 59b, and 59c are beveled obliquely as indicated by the arrows 52d, 54d to 59d, and 59e so that they can be smoothly inserted between the arms of the connection terminals on the battery pack 100 side.

[0041] Since the plate thickness of terminal portion 52a, terminal portion 57a, terminal portions 59b, 59c is larger than the initial gap (the gap when battery pack 100 is not attached) of the fitting portion of each arm portion, a predetermined fitting pressure acts on the fitting points of terminal portion 52a, terminal portion 57a, terminal portion 59b, 59c and upper positive terminal 162, upper negative terminal 167, lower positive terminal 172, and lower negative terminal 177. As a result of such connection, the device side terminals (terminal portion 52a, terminal portion 57a, terminal portions 59b, 59c) of the power tool main body 30 and the power terminals (upper positive terminal 162, upper negative terminal 167, lower positive terminal 172, lower negative terminal 177) of the battery pack are in good contact with each other in a state where electrical contact resistance is small. In this way, the electric device body 30 has a third terminal (52a) inserted into the single slot (122) and connected only to the first terminal (162) of the first and second terminals (162, 172), and a fourth terminal (59b) inserted into the single slot (122) and connected only to the second terminal (172). When the battery pack 100 is connected to the electric device body 30, the first and third terminals (162 and 52a) are connected to each other in the single slot 122 and are both at a first potential, and the second and fourth terminals (172 and 59b) are connected to each other and are both at a second potential different from the first potential. Since the negative terminal pair (167, 177) is also connected in a similar manner, the realization of the connection form of FIG. 6(1) results in the output of the series connection of the upper cell unit 146 and the lower cell unit 147, i.e., a rated voltage of 36 V, being output from the battery pack 100. The 36V power tool body 30 is an example of the "first electric device body" in the present invention. The short bar 59 of the 36V power tool body 30 is an example of the "series connection circuit" in the present invention, and the state in which the upper cell unit 146 and the lower cell unit 147 are connected in series is an example of the "series connection state" in the present invention.

[0042] On the other hand, when the battery pack 100 is attached to the conventional 18V electric power tool main body 1, the connection relationship is as shown in Fig. 6 (2). When the battery pack 100 is attached to the electric power tool main body 1, the positive input terminal 22 is press-fitted so as to push and spread both the open ends of the upper positive terminal 162 and the lower positive terminal 172, so that a part of the upper area of ​​the positive input terminal 22 contacts the upper positive terminal 162 and a part of the lower area contacts the lower positive terminal 172. The same is true for the negative input terminal 27. In this way, the arms 162a, 162b of the upper positive terminal 162 and the arms 172a, 172b of the lower positive terminal 172 are simultaneously fitted together, so that the positive terminals 162 and 172 are short-circuited, and the output of the parallel connection of the upper cell unit 146 and the lower cell unit 147, i.e., the rated 18V, is output to the electric power tool main body 1. The positive input terminal 22 and the negative input terminal 27 are made of metal plates having a certain thickness. Therefore, it is important that the fitting pressure by the arms of the upper positive terminal 162 and the upper negative terminal 167 is equal to the fitting pressure by the arms of the lower positive terminal 172 and the lower negative terminal 177. In order to make these fitting pressures constant, the thicknesses of the positive input terminal 52, the negative input terminal 57, and the terminal parts 59b and 59c of the short bar 59 of the 36V electric power tool body 30 shown in FIG. 9(1) are made the same as the thicknesses of the positive input terminal 22 and the negative input terminal 27 of the conventional 18V electric power tool body 1. The 18V electric power tool body 1 is an example of the "second electric device body" in the present invention. In addition, the positive input terminal 22 and the negative input terminal 27 of the 18V electric tool main body 1 are an example of a "parallel connection circuit" in the present invention, and the state in which the upper cell unit 146 and the lower cell unit 147 are connected in parallel is an example of a "parallel connection state" in the present invention.

[0043] As described above, the battery pack 100 of this embodiment can be attached to the power tool main body 1 for 18V or the power tool main body 30 for 36V, and the output of the battery pack 100 is automatically switched, realizing a battery pack 100 that is easy to use and compatible with multiple voltages. This voltage switching is not performed on the battery pack 100 side, but is performed automatically according to the shape of the terminal part on the power tool main body 1, 30 side, so there is no risk of voltage setting errors. In addition, since there is no need to provide a dedicated voltage switching mechanism such as a mechanical switch on the battery pack 100 side, a battery pack with a simple structure, low risk of failure, and long life can be realized. The short bar 59 that shorts the lower positive terminal 172 and the lower negative terminal 177 can be mounted in the same space as the existing terminal part 20 of the 18V battery pack, so a voltage switching battery pack with a size compatible with the conventional one can be realized. Furthermore, when charging is performed using an external charging device, charging is possible using the connection method shown in FIG. 6(2), so there is no need to prepare a charging device that can charge both high voltage and low voltage. When charging the battery pack 100 using an external charging device (not shown), charging is possible using the same charging device as a conventional 18V battery pack. In this case, the terminals of the charging device have the same shape as in FIG. 6(2), but instead of the positive terminals for discharge (162, 172), the positive terminals for charging (upper positive terminal 161, lower positive terminal 171) are connected to the positive terminals of the charging device (not shown). The connection situation at that time is also almost the same as the connection relationship shown in FIG. 6(2). In this way, charging is performed using a charging device for 18V with the upper cell unit 146 and the lower cell unit 147 connected in parallel, so there is no need to prepare a new charging device when charging the battery pack 100 of this embodiment.

[0044] Fig. 7(1) is a perspective view of the terminal section 50 of the electric power tool main body 30 of this embodiment. The terminal section 50 is manufactured by casting four metal connection terminals 54-56, 58 into a synthetic resin base 51 in addition to the positive input terminal 52, negative input terminal 57, and short bar 59 shown in Fig. 6(1). The shape of the connection terminals 54-56, 58 is a linear shape of the connection parts 52b, 57b of the positive input terminal 52 and the negative input terminal 57 in Fig. 6(1), and terminal parts 54a-56a, 58a that are fitted into the connection terminals on the battery pack 100 side are formed on one side, and holes are formed on the other side to form wiring parts 54c-56c, 58c for soldering lead wires, and connection parts 54b-56b, 58b that connect the terminal parts and the wiring parts and are cast in the synthetic resin are formed. The base 51 firmly holds the terminals 52a, 54a to 56a, and 58a by casting the entire upper side and the entire rear side of the terminals 52a, 54a to 58a. Also, a part of the rear of the lower side of the terminals 54a to 56a, and 58a is cast in. The short bar 59, the shape of which is shown in FIG. 6(1), has a connection part 59a (see FIG. 6) extending in the left-right direction entirely cast in the base 51, and the front parts of the terminals 59b and 59c are exposed forward from the base 51. Also, the lower part of the rear side of the parts of the terminals 59b and 59c exposed to the outside is cast in the base 51, so that the terminals 59b and 59c are firmly held so as not to move in the left-right direction. In this way, a plurality of plate-shaped device side terminals are arranged side by side in the terminal part 50. Here, terminal portion 52a and terminal portion 59b are arranged to be separated by a constant gap 53a in the vertical direction, while terminal portion 57a ​​and terminal portion 59c are arranged to be separated by a constant gap 53b in the vertical direction.

[0045] FIG. 7(2) is a diagram showing a connection state between the terminal section 50 and the power terminals (162, 172, 167, 177) of the battery pack 100. The upper positive electrode terminal 162 has two arms 162a, 162b (corresponding to the arms 205, 206 in FIG. 5(1)), and the lower positive electrode terminal 172 has two arms 172a, 172b (corresponding to the arms 225, 226 in FIG. 5(1)). The arms 162a, 162b of the upper positive electrode terminal 162 are connected to sandwich the plate-shaped terminal section 52a from the left and right. At the time of this joining, the arms 162a, 162b are bent so as to separate in the left and right directions, so that a predetermined clamping load (fitting pressure) is applied to the terminal section 52a by the restoring force of the spring action. As a result, the arms 162a, 162b and the terminal portion 52a are in good surface or line contact, realizing good conductivity with extremely low contact resistance. Similarly, the arms 167a, 167b of the upper negative terminal 167 are fitted to the terminal portion 57a ​​formed in a plate shape so as to sandwich the terminal portion 57a ​​from the left and right.

[0046] The arms 172a and 172b of the lower positive terminal 172 are fitted to the terminal 59b formed in a plate shape by sandwiching them from the left and right. During this fitting, the arms 172a and 172b are bent so as to separate in the left and right direction, and a predetermined clamping load (fitting pressure) is applied to the terminal 59b by the restoring force of the spring action. As a result, the arms 172a and 172b and the terminal 59b are in good surface contact or line contact, so that contact resistance is eliminated and good conductivity is achieved. Similarly, the arms 177a and 177b of the lower negative terminal 177 are fitted to the terminal 59c formed in a plate shape by sandwiching them from the left and right.

[0047] What is important in this embodiment is that the connection portion between the terminal portion 52a and the upper positive electrode terminal 162 and the connection portion between the terminal portion 59b and the lower positive electrode terminal 172 are kept in a non-contact state, thereby maintaining an electrically insulated state. Also, the connection portion between the terminal portion 57a ​​and the upper negative electrode terminal 167 and the connection portion between the terminal portion 59c and the lower negative electrode terminal 177 are kept in a non-contact state, thereby maintaining an electrically insulated state. With this configuration, even if the battery pack 100 vibrates at a resonance frequency different from that of the power tool main body 30 due to various vibrations and impacts during use of the power tool, it is possible to prevent a short circuit between the upper positive electrode terminal 162 and the lower positive electrode terminal 172, and to prevent a short circuit between the upper negative electrode terminal 167 and the lower negative electrode terminal 177. In addition, in Figure 7 (2), the connection terminals on the battery pack side that are fitted into the terminal portions 54a to 56a, 58a are not shown, but when the positive power terminal (upper positive terminal 162 and lower positive terminal 172) and the negative power terminal (upper negative terminal 167 and lower negative terminal 177) are connected, the signal terminals (T terminal 164, V terminal 165, LS terminal 166, LD terminal 168 shown in Figure 4) are also similarly fitted into the terminal portions 54a to 56a, 58a.

[0048] Fig. 8(1) is a perspective view of the terminal section 20 of a conventional electric power tool main body 1, and (2) is a diagram showing the connection state with the power terminal of the battery pack 100. The terminal section 20 is manufactured by casting six metal terminals 22, 24-28 into a synthetic resin base 21. As shown in Fig. 6(2) showing a part of the terminals 22, 27 before casting, the shape of the terminals 22, 24-28 is such that terminal sections 22a, 24a-28a that fit into the connection terminals on the battery pack 100 side are formed on one side, holes are formed on the other side to form wiring sections for soldering lead wires, and connection sections 22c, 24c-28c that connect the terminal sections and the wiring sections and are cast into the synthetic resin of the base 21 are formed. The base 21 firmly holds the terminals 22a, 24a to 28a by casting the entire upper side, the entire rear side, and a part of the rear of the lower side of the terminals 22a, 24a to 28a. The front corners of the terminals 22a, 24a to 28a are beveled as shown by arrows 22d, 24d to 28d, so that they can be smoothly inserted between the arms of the connection terminal on the battery pack 100 side. The shape of the terminal 20 is such that a groove 21b extending in the left-right direction is formed on the front side of the base 21, and a groove 21c extending in the left-right direction is formed on the rear side as well. These grooves 21b and 21c are held by the opening of the housing in the terminal 20.

[0049] FIG. 8(2) is a diagram showing the connection state between the terminal section 20 and the power terminals (162, 172, 167, 177) of the battery pack 100. Here, the signal terminals (T terminal 164, V terminal 165, LS terminal 166, LD terminal 168) on the battery pack 100 side are omitted from the illustration. The arms 162a and 162b of the upper positive terminal 162 are fitted to the terminal section 22a by sandwiching the upper region of the terminal section 22a formed in a plate shape from the left and right. During this fitting, the arms 162a and 162b are bent so as to separate in the left and right direction, so that a predetermined clamping load (fitting pressure) is applied to the terminal section 22a by the restoring force of the spring action. The arms 172a and 172b of the lower positive terminal 172 are fitted to the terminal section 22a by sandwiching the lower portion of the terminal section 22a formed in a plate shape from the left and right. The arms 167a, 167b, 177a, and 177b of the upper negative terminal 167 and the lower negative terminal 177 of the power terminal are fitted in a similar manner. In this manner, the four arms 162a, 162b, 172a, and 172b come into contact with one terminal portion 22a. Similarly, on the negative side, the arms 167a and 167b of the upper negative terminal 167 fit together to sandwich the upper region of the plate-shaped terminal portion 27a from the left and right, and the arms 177a and 177b of the lower negative terminal 177 fit together to sandwich the lower portion of the terminal portion 27a from the left and right. In this way, the four arms 162a, 162b, 172a, 172b come into contact with one terminal portion 22a, and similarly the four arms 167a, 167b, 177a, 177b come into contact with terminal portion 27a, so that these can make good surface contact or line contact, eliminating contact resistance and achieving good conductivity.

[0050] Next, the shape of the parts used for the three terminals (164-166), i.e., the signal terminal part 240, will be described with reference to FIG. 9. The signal terminal part 240 is manufactured by pressing a single metal plate, and is formed by bending a thin metal plate into a U-shaped base part 241 so that a bridge part 242, which is the bottom part of the U-shape, is the vertical plane on the rear side. From the base part 241, the arm part set (arm part bases 245, 246) extends forward, the arm part base 245 is formed so as to be separated into upper and lower arm part sets (arm parts 251, 253), and the arm part base 246 is formed so as to be separated into upper and lower arm part sets (252, 254) by forming a notch groove 244b extending horizontally. The metal plate used for pressing is a flat plate with a thickness of 0.3 mm, which may be thinner than the plate thickness of 0.5 mm of the upper terminal part 200 and the lower terminal part 220 used for the power terminal. The upper and lower arm sets are formed in the same shape, and have the same length in the front-rear direction, width in the up-down direction, plate thickness, etc. The upper arm set (arms 251 and 252) and the lower arm set (arms 253 and 254) are each formed with a fitting portion (251d, 253d, etc.), and the curved shape for the fitting portion is also the same on the top and bottom, and the left and right arms are made to have a plane-symmetrical shape. Meanwhile, the attachment positions of the legs 249 and 250 are arranged so as to be largely shifted in the front-rear direction. The shape of the lower side portion of the base part 241 is different on the left and right, and the shapes of the right side surface 243 and the left side surface 244 are asymmetric. The leg 249 is arranged to be largely shifted forward compared to the position of the conventional leg 250, and the legs 249 and 250 are separated by a large distance in the front-rear direction. In this way, legs 249 and 250 are not arranged next to each other in the left-right direction, but are arranged so as to be shifted forward and backward, so that an extension part 243a that extends significantly forward is formed near the lower edge of right side surface 243, and leg 249 is formed so as to extend downward from the front end part. Legs 249 and 250 are each fixed to circuit board 150 by passing through a through hole (not shown) formed in circuit board 150 from the front surface to the back surface side and soldering the parts protruding to the back surface side, and the upper arm set (arms 251 and 252) and the lower arm set (arms 253 and 254) are electrically connected to an electronic element mounted on circuit board 150.

[0051] Above the leg 249, a bent portion 243b is formed that is bent to the left in order to limit the amount of insertion into the mounting hole 151 (see FIG. 4) of the circuit board 150. Semicircular cutouts 243c and 249a are formed above and below the bent portion of the bent portion 243b in order to facilitate the bending process. Steps 250a and 250b formed on the front and rear sides of the leg 250 are used to position the rear leg 250 on the circuit board 150. The step 250a is formed by extending the lower edge portion of the left side surface 244 forward, and the step 250b is formed by utilizing the lower edge portion of the bridge portion 242 that is curved in a U-shape. In this way, the step portions 250a and 250b come into contact with the surface of the circuit board 150, thereby allowing the vertical mounting position of the leg 250 to be determined. The attachment positions of the legs 249 and 250 in the front-rear direction are determined by the position of the attachment holes 151 of the circuit board 150 (see FIG. 4).

[0052] 9(2) is a view of the signal terminal part 240 alone, seen from the front and below. As can be seen from this figure, a horizontally extending notch groove 245b is formed on the front side of the arm base 245, which separates the arm base 245 into upper and lower arm sets (arms 251, 253). The right leg 249 is disposed so as to be shifted significantly forward compared to the left leg 250. As a result, the signal terminal part 240 can be firmly held on the circuit board even if an upward or downward force is applied to the four arms 251, 252, 253, 254. When the battery pack 100 is attached to the power tool main body 1, 30, an external force is applied to the arms 251, 252, 253, 254 so as to push the arm set backward, and this force is in a direction that tilts the signal terminal part 240 backward. Conversely, when the battery pack 100 is removed from the power tool main body 1, 30, a force is applied to the arm assembly forward, and this force is in a direction that causes the signal terminal part 240 to fall forward. In this way, the external force applied when the battery pack 100 is attached and removed can be effectively received by shifting the positions of the legs 249, 250 in the front-rear direction, and the mounting rigidity of the signal terminal part 240 can be significantly strengthened, thereby improving the durability of the battery pack 100. Furthermore, since the arm assembly is also formed in two stages, upper and lower, the four contact areas of the arm part can maintain a good contact state with the terminal on the power tool main body side even if it is subjected to various vibrations or external forces during the operation of the power tool. Meanwhile, the number of mounting holes and the number of soldering points of the circuit board 150 required for manufacturing this signal terminal part 240 are the same as those of the conventional ones, and therefore an increase in manufacturing costs can be suppressed.

[0053] The signal terminal part 240 of this embodiment not only improves the rigidity, but also has another effect. A conventional signal terminal part (not shown) has two legs that are soldered to a circuit board for electrical and mechanical attachment, but the legs are arranged in parallel in the left-right direction, and the distance between the legs is narrow and the soldered parts are often connected, making it impossible to wire a signal pattern between the left and right legs. In the battery pack 100 of this embodiment, one leg 249 of the signal terminal part 240 is arranged on the front side, and the other leg 250 is arranged on the rear side, with both legs spaced apart. This widens the distance between the legs of the signal terminal part 240, making it easy to wire multiple wires or a thick pattern that carries a main current. Such a signal terminal part 240 is suitable for the battery pack 100 of this embodiment, i.e., for the conventional battery pack, when it is desired to improve the functionality and promote miniaturization in terms of voltage ratio. In particular, if the voltage is increased and a voltage switching function is realized, the number of electronic elements mounted on the circuit board 150 increases. Therefore, it became necessary to improve the efficiency of the pattern wiring and to thicken the wiring that carries the main current. In this embodiment, a circuit board 150 larger than that used in the past was used, and electronic elements were mounted not only on the rear side of the connection terminal group but also on the front side area. At that time, the wiring pattern was arranged also on the lower side of the signal terminal component 240. The method of arrangement will be explained using FIG. 10.

[0054] 10 shows how a plurality of signal terminal components 240 are fixed to the circuit board 150, where (1) is a view from the front, and (2) is a view of the signal terminal components 240 as seen from the left. The signal terminal components 240 are common components, and are fixed to the circuit board 150 as the T terminal 164, the V terminal 165, and the LS terminal 166, arranged at a distance S4 from each other in the left-right direction. The signal terminal components 240 have a cutout portion 255 (see FIG. 9(2)) formed near the center of the arm to create a space S2, so that the signal terminal components 240 have a shape in which the upper arm set (251, 252) and the lower arm set (253, 254) are present in two stages, one above the other. When the device side terminal is not attached, the closest portions (fitting portions) of the upper arm set (251, 252) and the lower arm set (253, 254) are arranged so as to be spaced apart by a small gap or to be in contact with each other. Each of the legs 249, 250 passes through a mounting hole (see FIG. 4) of the circuit board 150, protrudes downward, and is fixed to the underside (backside) of the circuit board 150 by solder 256.

[0055] In the side view of FIG. 10(2), the leg 249 located at the front and the leg 250 located at the rear are configured to be spaced apart by a distance S3. The distance S3 should be greater than the distance (distance in the left-right direction) between the legs 249 and 250. By forming a gap like the arrow 257 in this way, it becomes easy to wire a circuit pattern in this gap. FIG. 10(3) is a bottom view of the circuit board 150 of FIG. 10(1) seen from the bottom. A through hole is formed in the center of the back surface of the circuit board 150 to solder the signal terminal component 240, and lands 153a to 155a and 153b to 155b are formed around the through hole, with copper foil for soldering being approximately rectangular. The wiring patterns for connecting the lands 153a to 155a and 153b to 155b to the upper cell unit 146 or the lower cell unit 147 are on the front surface side of the circuit board 150 and are not visible in the view of (3). The lands 153a-155a for the left leg and the lands 153b-155b for the right leg are arranged so as to be shifted forward and backward. As a result, it is possible to arrange a plurality of patterns 157-159 between the lands 153a-155a and the lands 153b-155b as shown in the figure. Here, the wiring patterns 157-159 are illustrated as being provided with three each, but they may be one thick wire or a combination of other numbers. Since the wiring patterns are arranged between the legs 249, 250 arranged so as to be shifted forward and backward in this way, it is possible to provide a plurality of wiring patterns 157-159 connecting the rear side and the front side of the signal terminals 164-166 while maintaining the same interval between the adjacent signal terminals 164 and 165, and 165 and 166 as in the conventional case. As another method for increasing the number of wiring patterns connecting the rear side and front side of the signal terminals 164-166, a method of providing a cutout 243c as shown by a dotted line in Fig. 10(2) may be used in combination. The cutout 243c is cut out upward as shown by a dotted line near the bottom edge of the right side surface 243, in the portion that contacts the circuit board 150. Then, the portion indicated by the arrow 257 becomes a gap that separates the circuit board 150. It is possible to arrange a circuit pattern between this gap and the circuit board 150, similar to the wiring patterns 157-159 in Fig. 10(3).In this way, multiple wiring patterns connecting the rear and front sides of the signal terminals 164-166 can be arranged not only on the back side 150b of the circuit board but also on the front side 150a, thereby making it possible to improve the execution efficiency of the circuit board 150.

[0056] 11 is a diagram showing the shape of the connection terminal group (161-162, 164-168) and the board cover 180 arranged around it, (1) being a perspective view and (2) being a front view. Here, the illustration of the circuit board 150 is omitted for the sake of understanding the invention, and in an actual product, after the multiple connection terminal groups (161-162, 164-168, 171, 172, 177) are fixed to the circuit board 150 by soldering, the board cover 180 is attached around the connection terminals. The power terminals (161, 162, 167) are formed so as to be higher by a distance H in the upward direction than the signal terminals (164-166, 168). The board cover 180 is a member made of a non-conductor, for example, a molded product of synthetic resin, and is adapted to cover the periphery of the legs of adjacent connection terminals. It has a connecting portion 181 having a flat upper surface 181a on the front side, and a plurality of partition walls 182, 183, 184-189 are connected to the rear side of the connecting portion 181. The partition walls 182, 183, 184-189 are arranged on the rear side of the flat portion 181a, i.e., on the left and right parts of the group of connection terminals, thereby serving to prevent electrical short circuits between the connection terminals. The upper surface 181a of the connecting portion 181 is formed to be flush with the upper surface 115 (see FIG. 3) of the upper case 110, facilitating the relative movement of the main body side terminal portion from the upper surface 115 to the connecting portion 181. Furthermore, the board cover 180 is provided with a cover portion 184 that closes the opening of the unused area (slot 123 in FIG. 3), making it difficult for dirt or dust to enter the inside of the battery pack 100 case through the slot 123.

[0057] The board cover 180 is mainly formed by a connecting portion 181 having a horizontal upper surface 181a in the horizontal direction, and a plurality of partition wall portions extending upward therefrom. Among the partition wall portions, partition walls 185, 186, and 189 arranged between the signal terminals are low walls having a height H2, and their upper end positions are lower than the signal terminals (164 to 166) and the lower arm portion of the LD terminal 168. In contrast, adjacent partition walls 182, 183, 184a, 187, and 188 for the power terminals are high walls having a height H3 from the upper surface 181a, and their upper end positions are configured to be located above the upper end positions of the lower terminal components and below the arm portions of the upper terminal components.

[0058] As described with reference to Figs. 5 to 8, the power terminals among the connection terminal group are arranged such that the legs of the upper positive terminals 161, 162 and the lower positive terminals 171, 172 are aligned in the front-rear direction, and the respective arm sets are aligned in the up-down direction. Similarly, the legs of the upper negative terminal 167 and the lower negative terminal 177 are aligned in the front-rear direction, and the respective arm sets are aligned in the up-down direction. When the battery pack 100 is attached to an electric device body rated at 18V, the potential of the arms of the upper positive terminal 162 and the upper negative terminal 167 and the potential of the lower positive terminal 172 and the lower negative terminal 177 are the same, so there is no problem even if the upper terminal parts and the lower terminal parts come into contact with each other. However, when the battery pack 100 is attached to an electrical device main body rated at 36V, the potentials of the upper positive electrode terminal 162 and the upper negative electrode terminal 167 are different from the potentials of the lower positive electrode terminal 172 and the lower negative electrode terminal 177, so it is important to prevent a short circuit state caused by contact between the upper and lower arms. In addition, it is preferable to make the shape such that a short circuit caused by the insertion of a foreign object is unlikely to occur. Therefore, in the board cover 180 of this embodiment, among the partition wall parts formed to extend upward from the connecting part 181, the partition walls 182, 183, 184a, 187, and 188 are formed so that the upper end positions are large upward to a height H3. In addition to the wall parts extending vertically upward, horizontal wall parts extending in the left and right directions from the upper end positions of the vertical wall parts are also formed.

[0059] FIG. 11(3) is a partially enlarged view of the board cover 180 of (2), excluding the connection terminal portion. The partition wall 182 has a vertical wall portion 182a and a horizontal wall portion 182b, and has an L-shaped cross section. The horizontal wall portion 182b is shaped to extend horizontally from near the upper end of the vertical wall portion 182a to reach the space between the arms of the adjacent power terminals (upper positive terminal 161, lower positive terminal 171). The partition wall 183 has a T-shaped cross section and is formed by the vertical wall portion 183a and horizontal wall portions 183b and 183c extending in both directions from the upper end of the vertical wall portion 183a. The horizontal wall portion 183b extends to the side adjacent to the adjacent horizontal wall portion 182b, and has a length such that its tip reaches the space between the arms of the upper positive terminal 161 and the lower positive terminal 171. Similarly, the horizontal wall portion 183c extends to the side adjacent to the adjacent horizontal wall portion 184b, and has a length such that its tip reaches the space between the arms of the upper positive terminal 162 and the lower positive terminal 172. The state in which the horizontal walls 182b, 183b, and 183c extend into the space between the arms will be clear when viewing the positive terminal group from the front as in FIG. 11(2). For example, the right side position of the upper positive terminal 161 and the right side position of the lower positive terminal 171 are in the same position. However, the left end position 182c of the horizontal wall portion 182b is long enough to reach the lower part of the arm portion 161a of the upper positive terminal 161 so as to extend further left than the left side position of the upper positive terminal 161 and the lower positive terminal 171. The horizontal wall portion 182b is located above the arm portion 171a of the lower positive terminal 171.

[0060] The length in the front-rear direction of the vertical wall portion 182a and the horizontal wall portion 182b is formed to be longer than the length in the front-rear direction of the lower positive electrode terminal 171, the front end position is at approximately the same position as the tip of the arm portion of the lower positive electrode terminal 171, and the rear end position is rearward of the rear end position of the lower positive electrode terminal 171. In this way, the vertical wall portion 182a covers the entire right side surface of the lower positive electrode terminal 171, and also covers the upper part except for the vicinity of the left-right center (part of distance S5). Furthermore, the vertical wall portion 183a covers the entire left side surface of the lower positive electrode terminal 171 and the entire right side surface of the lower positive electrode terminal 172, and also covers the upper part except for the vicinity of the left-right center. Here, only the shapes of vertical wall portion 182a and horizontal wall portion 182b of lower positive terminal 171 have been mentioned, but lower positive terminal 172 is also provided with partition walls 183, 184 that cover the entire right side surface, the entire left side surface, and the upper portion excluding the central portion. Therefore, even if an external force is applied to lower positive terminals 171, 172, tending to bend them, they can be effectively held in place by board cover 180, and the risk of an unintentional short circuit between the lower terminal components for power transmission and the upper terminal components can be significantly reduced.

[0061] The negative electrode terminal side (167, 177) is also provided with large partition walls 187, 188 on both the left and right sides of the negative electrode terminal, based on the same concept as the positive electrode terminal side (161, 162, 171, 172). Partition wall 187 has the same shape as partition wall 182, is formed by a vertical wall portion 187a and a horizontal wall portion 187b, and has an L-shaped cross section. Horizontal wall portion 187b is formed so as to extend from the upper end portion of vertical wall portion 187a to the negative electrode terminal side. Partition wall 188 is formed symmetrically to partition wall 187, and is formed by a vertical wall portion 188a and a horizontal wall portion 188b. The horizontal walls 187b and 188b are sized so that their tip portions can fit into the space between the arm set of the upper negative terminal 167 and the arm set of the lower negative terminal 177, but have a predetermined gap S5 so as not to impede the entry of device side terminals such as the power tool main body 1, 30. Since the partition walls 187, 188 are formed so as to cover the periphery of the negative terminal (167, 177) serving as the power terminal in this manner, even if a strong external pressure is applied to the upper negative terminal 167 or the lower negative terminal 177 and it moves (bends) in the forward / backward direction, the presence of the walls such as the horizontal walls 187b and 188b can significantly reduce the possibility of a short circuit occurring.

[0062] The partition walls 185, 186 between the signal terminal groups (164-166) have a low height H2 in the upward direction. This is because only low-power signals flow through the signal terminal groups (164-166), so the risk of short circuiting is significantly smaller than that of the power terminals. Also, each of the signal terminal groups (164-166) is a single part, and the upper arm and the lower arm are at the same potential, so there is little need to worry about short circuiting. The same is true for the partition wall 189. The partition wall 184 includes vertical wall portions 184a, 184d, and is connected between them to a blocking plate 184c. The blocking plate 184c is a flat plate extending vertically and laterally, and serves to close the empty space (the internal space of the empty slot 123 in FIG. 3) between the upper positive terminal 162 and the lower positive terminal 172 and the T terminal 164. Near the upper end of the vertical wall portion 184a, a horizontal wall portion 184b is formed, which extends toward the positive electrode terminal side.

[0063] The connecting portion 181 is connected to the front surfaces of the vertical walls 182a, 183a, 184a, 184d, 185a, 186a, 187a, and 188a located between the connection terminals, and fixes them. The wall of the upper surface 181a of the connecting portion 181 is formed so as to be floating above the circuit board 150. The inner portion (lower portion) of the connecting portion 181 is formed so as to have a space, and the vertical walls 184a, 185a, 186a, and 187a are disposed on the rear side. Although it is hidden by the front wall surface 181b and cannot be seen here, the vertical walls 182a, 183a, 184d, and 188a are also formed so as to extend downward and contact the circuit board 150. The inner portion of the connecting portion 181 is filled with a liquid hardening resin that covers the upper surface of the circuit board 150 as described later in FIG. 13, and then hardened. As the hardening resin solidifies, the lower ends of the vertical walls 182a, 183a, 184a, 184d, 185a, 186a, 187a, and 188a are firmly fixed to the circuit board 150. Three notches 181c to 181e are formed in the front wall 181b of the connecting portion 181. The notches 181c to 181e are formed so that the liquid resin, which will be described later in FIG. 13, can be evenly distributed to the rear and front parts of the circuit board 150, and because the liquid resin has a relatively low viscosity, the resin flows in the front-rear direction through the notches 181c to 181e (details will be described later).

[0064] FIG. 12 is a view of only the upper case 110 of FIG. 3, and is a view for explaining the shape of the upper surface 115 of the upper case 110. FIG. 12(1) is a perspective view of the upper case 110, and (2) is a view seen from the direction of the arrow B in (1). In (1), the stepped portion is hatched to clarify its range. As explained in FIG. 11, the power terminals (161, 162, 167) are formed to be higher in the upward direction than the signal terminals (164-166, 168) by a distance H. This is because the power terminals are formed of a thicker plate material than the signal terminals. Therefore, in the conventional shape of the upper surface of the upper case, the upper ends of the power terminals (161, 162, 167) interfere with the inner wall of the upper surface. Therefore, in this embodiment, the position of the inner wall surface of the upper surface 115 of the upper case 110 in the vertical direction is partially shifted upward to secure clearance above the power terminals (161, 162, 167). Although it is possible to form only the position of the inner wall surface as a recess recessed upward, if the cross-sectional shape of the upper surface 115 is left as is, there is a risk that the thickness of a part of the upper surface 115 of the upper case 110 will be insufficient, resulting in a local decrease in strength. Therefore, in this embodiment, the outer surface of the upper surface 115, in the upper part near where the power terminals (161, 162, 167) are located, is formed with convex parts 115a, 115b that protrude outward. Since the wall surface of the upper surface 115 is shifted upward in this way, the storage space can be expanded in the inner part, and a decrease in the wall strength can be prevented. In this embodiment, the protruding height H4 of the outer wall surface of upper surface 115 is configured to be smaller than the recessed height H5 of the inner wall surface, so that the size of convex portions 115a, 115b on upper surface 115 can be kept small and within a range that allows for easy attachment to a conventional power tool body 1. In addition, upper surface 115 is not flush, but has a partial step portion formed therein such that the height of the shaded portion is higher, so that the strength can be made equal to or greater than that of a conventional flush upper case.

[0065] Next, a method of applying resin to the circuit board 150 will be described with reference to FIG. 13. FIG. 13 is a perspective view of the circuit board 150. Although not shown here, the circuit board 150 has a main region 156a and a sub-region 156b on the upper surface (front surface) thereof for mounting electronic elements. The main region 156a is located behind the group of connection terminals, and a protection management IC (described later) including a microcomputer is mounted therein. The sub-region 156b is located in front of the group of connection terminals. Here, the electronic elements to be mounted are entirely covered with a hardening resin. The hardening resin is one that hardens from a liquid state, and for example, a urethane resin can be used. In order to fill the upper surface of the circuit board 150 evenly with the liquid urethane resin, first, an adhesive resin 155 that acts as a dike to prevent the liquid resin from flowing out is attached to the outer edge of the group of elements to be mounted on the circuit board 150. The adhesive resin 155 is extracted in a cylindrical shape from a tube-shaped container through a thin extraction port, for example, and is applied continuously along the outer edge of the area to be filled with urethane resin. At this time, it is important that the adhesive is applied seamlessly along the outer edge, and one end and the other end are formed so that they contact the board cover 180. After the adhesive resin 155 that forms the outer frame is applied around almost the entire circumference of the outer edge where the resin is poured, the urethane resin in a liquid state is then poured onto the inside of the upper surface of the circuit board 150.

[0066] The amount of urethane resin poured is set to an amount that sufficiently fills the area surrounded by the adhesive resin 155. At this time, the outer edge of the area that is not to be covered with resin is surrounded by the adhesive resin 155a to 155c, so that the resin poured outside of the area does not reach the area surrounded by the adhesive resin 155a to 155c. If the position where the urethane resin is poured is the vicinity of the main area indicated by the arrow 156a, the resin does not flow into the area surrounded by the adhesive resin 155a. In addition, the board cover 180 has a wall surface of the connecting portion 181 forming the upper surface 181a in a floating state, the rear side wall surface of the lower part is in an open state, and the front side becomes a wall surface, and the notches 181c to 181e are formed in parts of the wall surface, so that the resin can flow well from the main area 156a to the sub area 156b. In this way, by covering the entire element mounting surface of the circuit board 150 with resin and then curing it, the surface side of the circuit board 150 is covered with resin at a uniform height within the target range without any gaps, and the mounted electronic elements can be protected from the effects of water and dust. If a double-sided board is used as the circuit board 150, the back side may also be covered with resin in a similar manner. In addition, resin may be applied to the parts that are not filled with resin by the adhesive resin 155, such as the vicinity of the screw holes and the soldered parts of the lead wires, in a process after the screws are tightened or in a process after the soldering is completed.

[0067] Although the first embodiment of the present invention has been described above with reference to Figs. 1 to 13, various modifications are possible to the battery pack 100 shown in the first embodiment. Fig. 14 is a diagram showing the shapes of the upper terminal part 260 and the lower terminal part 280 according to a first modification of this embodiment. Fig. 14(1) is a perspective view, (2) is a left side view, and (3) is a front view. The upper terminal part 260 and the lower terminal part 280 each have two arm sets (265 and 266, 285 and 286) in the left-right direction, and the two arm sets are aligned in the up-down direction, as in the first embodiment. The leg set (267, 268) of the upper terminal part 260 is arranged to be aligned in the front-rear direction with the leg set (287, 288) of the lower terminal part 280, as in the first embodiment. At the lower portions of the rear edges of the right side surface 263, 283 and the left side surface 264, 284, as shown by arrows 262a, 282a in (2), bridge portions 262, 282 protrude in a curved manner toward the rear, and these protruding portions are used for vertical positioning when upper terminal component 260 and lower terminal component 280 are attached to circuit board 150. At the upper portions of the front edges of legs 267, 268, 287, and 288, convexly extending portions are bent inwardly to form bent portions 263a, 264a, 283a, 284a (however, 263a is not visible in FIG. 14), and the shapes of these bent portions are the same as those of the first embodiment shown in FIG. 5.

[0068] The direction of bending the upper terminal part 260 into a U-shape is different from that shown in FIG. 5. Here, the part that becomes the bottom when bent into a U-shape, i.e., the bridge part 262, is formed so as to be a vertical plane. The bending shape of the lower terminal part 280 is the same as that of the lower terminal part 220 shown in FIG. 5, and the bridge part 282 is a vertical plane. The bridge parts 262 and 282 are arranged in parallel to each other with a substantially constant interval in the front-rear direction, and are arranged to extend in a substantially vertical direction with respect to the surface of the circuit board 150. The upper terminal part 260 and the lower terminal part 280 are manufactured by pressing a metal plate in the same manner as in the first embodiment, but the thickness of the plate is made thicker.

[0069] The right side surface 263 and the left side surface 264 are substantially rectangular extending in the vertical direction, and are formed so that the arms 265, 266 extend forward near the upper ends. The width (vertical length) of the arms 265, 266 is large near the rear base, i.e., near the chain line B2, and the width gradually decreases toward the front, and the width is constant further forward than the imaginary line B1. The fitting portions 265d, 266d are bent inwardly into a curved shape having a predetermined radius of curvature R1 when viewed from above, as in the first embodiment shown in FIG. In this way, the arms 265, 266 are formed so as to extend forward from the upper front edge of the U-shaped base portion, and the arms 265, 266 are formed so as to have spring properties in a non-contact state with each other.

[0070] The lower terminal part 280 has a right side surface 283 and a left side surface 284 formed in parallel by bending them in a U-shape, and a bridge part 282 connecting them. From the elongated upper parts of the right side surface 283 and the left side surface 284, arms 285 and 286 are provided so as to extend forward and diagonally upward. The vertical width of the arms 285 and 286 is almost constant in the front-rear direction, and they are formed so as to extend horizontally forward of the imaginary line B1, but are arranged diagonally behind the imaginary line B1. A notch part 291 is formed below the arm set (285, 286) of the lower terminal part 280, which is largely cut out from the front side. As a result of being formed in this way, the length of the arms 265 and 266 of the upper terminal part 260 (the length in the front-rear direction and forward of B2) is longer than the length of the arms 285 and 286 of the lower terminal part 280 (the length in the front-rear direction and forward of the position of the arrow 291). Even in the case of such arm sets having different lengths in the front-rear direction, it is preferable that the fitting pressure at the fitting portion of the upper terminal part 260 is the same as the fitting pressure of the lower terminal part 280. If the fitting pressure is not uniform, the contact resistance with the flat device side terminal on the electric power tool main body 1, 30 side may change, causing slight differences in heat generation and differences in wear conditions due to long-term use. In this modification, in order to balance the fitting pressures of the upper terminal part 260 and the lower terminal part 280, the initial gap distances in the non-attached state of the battery pack are made different. That is, in the state where the battery pack 100 is not attached to the electric power tool main body 1 or 30 (dismounted state), the minimum distance between the left and right arms 265, 266 is different from the distance between the arms 285, 286. Here, the distance between the arms 265 and 266 of the upper terminal part 260 is 0.2 mm, whereas the minimum distance between the arms 285 and 286 of the lower terminal part 280 is set to 0.5 mm.

[0071] In order to make the fitting pressure uniform, the shapes of the upper terminal part 260 and the lower terminal part 280 are also devised. That is, as shown in FIG. 14(2), the upper terminal part 260 should originally have a nearly right-angled interior angle as shown by the dotted line 264b, but here, the contour of the dotted line 264b is extended in the direction of the arrow 264e, and a reinforcing surface 264c in the shape of a right-angled triangle is added in side view. As a result, the contour of this interior angle becomes inclined as shown by the arrow 264d, and this change in shape improves the mounting rigidity of the arms 265 and 266 of the upper terminal part. In accordance with the change in shape of the interior angle of the upper terminal part 260, the shape of the exterior corner of the lower terminal part 280 is cut off from the part of the dotted line 284b in the direction of the arrow 284e, so that a cut-off part 284c in the shape of a right-angled triangle is provided in side view. As a result, the outline of the outer corner portion becomes as shown by the arrow 284d, and the rigidity of the arms 285 and 286 of the lower terminal part is reduced. The outlines of the outlines of the arrows 264d and 284d are determined so that they are spaced apart at a certain distance so that they are almost parallel to each other in a side view. If the cut-off portion 284c is formed, the length of the bridge portion 282 in the vertical direction will be shortened. However, since the lower terminal part 280 is small and has sufficient strength compared to the upper terminal part 260, these shape changes can achieve a balance in strength. In this way, by changing the shape of the inner corner portion of the upper terminal part 260 by adding the reinforcing surface 264c, and by changing the shape of the outer corner portion of the lower terminal part 280 by adjusting the strength by forming the cut-off portion 284c, it is possible to balance the strength of both and make the fitting pressure of the arms 265 and 266, and 285 and 286 to the main body side terminal almost equal.

[0072] FIG. 14(3) is a front view of the upper terminal part 260 and the lower terminal part 280. The vertical height and mounting position of the arms 265 and 266, and the vertical height and mounting position of the arms 285 and 286 are the same as those of the arms of the upper terminal part 200 and the lower terminal part 220 of the first embodiment shown in FIG. 5. However, the thickness of the metal plate material used in this modification is different, and the terminal parts are manufactured using a thicker plate than that of the terminal parts of the first embodiment shown in FIG. 5. Furthermore, when the battery pack 100 is not attached, the minimum interval between the upper and lower arm sets is different. That is, the horizontal interval between the lower arms 285 and 286 is larger than the horizontal interval between the upper arms 265 and 266. This is a relationship in which the lengths of the arms 265 and 266 and the arms 285 and 286 arranged vertically are inversely proportional to each other in the attachment direction (front-back direction). In the initial state, the long arms 265 and 266 face each other with a narrow gap between them, whereas the short arms 285 and 286 face each other with a wide gap between them.

[0073] As described above, in the first modified example, the upper terminal part 260 and the lower terminal part 280, each having a relatively thick plate thickness of 0.8 mm, are used as the power terminals. Since only a small current flows through the signal terminal parts, they may be manufactured from a metal plate having a thickness of about 0.3 mm, as in the conventional 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 state can be maintained well not only during operation but also over a long period of use. Note that the mating pressure of the upper and lower arm assemblies can be made approximately the same by not only adjusting the gap of the mating parts and changing the shape near the mounting base, but also by other changes, particularly adjustment of the plate thickness and selection of the material of the terminal parts.

[0074] FIG. 15 is a perspective view showing an upper terminal part 260 and a lower terminal part 280A of a second modified example of this embodiment. In the second modified example, the upper terminal part 260 is the same as the first modified example shown in FIG. 14, but the lower terminal part 280A has a different plate thickness and an initial interval of the arm parts. That is, the plate thickness of the lower terminal part 280A is made thinner from 0.8 mm of the lower terminal part 280 shown in FIG. 14 to 0.6 mm, and the interval between the fitting parts 285d and 286d is made narrower from 0.5 mm of the lower terminal part 280 shown in FIG. 14 to 0.2 mm. The interval between the fitting parts 265d and 266d of the upper terminal part 260 is 0.2 mm, as in the first modified example. In this way, by adjusting the plate thickness and interval of the arms 285 and 286 having spring properties, the fitting pressure by the fitting parts 265d and 266d of the upper terminal part 260 can be made almost equal. Here, the shape of the fitting parts 265d, 266d is a semi-cylindrical surface, the central axis of the cylindrical surface is located in the vertical direction, and the inner wall surface of the fitting parts 265d, 266d is a cylindrical surface with a curvature radius R1. The inner wall surfaces of the fitting parts 285d, 286d of the lower terminal part 280A are also formed to be cylindrical surfaces with a curvature radius R1. The cylindrical shapes of the fitting parts 265d, 266d and the fitting surfaces of the fitting parts 285d, 286d are preferably formed with the same curvature radius R1 so that the size and shape of the linear or rectangular contact parts are approximately the same. By making the size of the contact parts and contact areas uniform in this way, it is preferable to make the clamping pressure (fitting pressure) approximately the same and the electrical contact resistance approximately the same.

[0075] FIG. 16 is a perspective view showing an upper terminal part 200A and a lower terminal part 220 according to a third modified example of this embodiment, and (1) is a view showing a state in which they are connected to the main body side terminal of the electric power tool main body 30A rated at 36V. In the third modified example, only the shape of the upper terminal part 200A, particularly the shape of the arm parts 205A and 206A, is different from that of the first embodiment, and the configuration of the base part and the leg part of the upper terminal part 200A is the same as that of the first embodiment. The upper terminal part 200A is used as the upper positive electrode terminals 161 and 162 and the upper negative electrode terminal 167. The upper terminal part 200A has the arm parts 205A and 206A extended largely forward, so that the position of the fitting part of the upper arm parts 205A and 206A is located forward of the position of the fitting part of the lower arm parts 225 and 226. The shape of the opposing fitting parts is a semi-cylindrical surface having the same radius of curvature R1, and the shape of the fitting parts of the arms 205A, 206A is the same as that of the fitting parts of the arms 225, 226. When the arms 205A, 206A are extended, the positive terminal 72A of the 36V side power tool body is also made shorter than before to correspond to this change in shape. The size and thickness of the short bar 79 as the shorting means are the same as those of the short bar 59 shown in FIG. 6. However, a semicircular notch 79d is formed in the upper part of the terminal part 79b of the short bar 79. This notch 79d is for preventing the terminal part 79b from contacting the upper arm parts 205A, 206A when the positive terminal 72A of the device side terminal and the terminal part 79b move relatively in an arc shape or horizontally as shown by the arrow 45a for some reason. By forming the notch 79d in this manner in the terminal portion 79b of the short bar 79, even if a relative positional misalignment occurs due to the difference in the resonant frequencies of the power tool main body 30A and the battery pack 100 when the battery pack 100 is attached and the power tool is operating, the risk of a short circuit between the upper terminal part 200A and the lower terminal part 220 can be significantly reduced.

[0076] FIG. 16(2) is a diagram showing a state where the power tool is connected to the main body side terminal of the conventional power tool main body 1. When the power tool is attached to the power tool main body 1 rated at 18V, the two sets of arms 205A, 206A and arms 225, 226 are fitted to the positive input terminal 22. At this time, the contact position of the fitting parts of the arms 205A, 206A with the positive input terminal 22 is shifted forward from the contact position of the fitting parts of the arms 225, 226 with the positive input terminal 22. However, since the thickness of the positive input terminal 22 in the vicinity including each contact position is uniform, if the size of the contact part or contact area by the arms 205A, 206A and the fitting parts of the arms 225, 226 is uniform, a good conductive state can be realized, and the movement of the contact position does not cause any problem.

[0077] FIG. 17 is a perspective view showing the upper terminal part 200 and the lower terminal part 220A of the fourth modified example of this embodiment, and (1) is a view showing a state in which they are connected to the main body side terminal of the electric power tool main body 30B. In the fourth modified example, only the shape of the arms 225A and 226A of the lower terminal part 220A is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. Here, the arms 225A and 226A are extended forward so that the position of the fitting part of the lower arms 225A and 226A is located forward of the position of the fitting part of the upper arms 205 and 206. In response to this, the rear end position of the short bar 79 is also moved forward more than in the conventional case. Furthermore, a semicircular notch 72d is formed in the lower part of the positive terminal 72B. The purpose of this cutout 72d is to significantly reduce the risk of positive terminal 72B coming into contact with arm portions 225A, 226A if, for some reason, positive terminal 72B and terminal portion 79b of the device side terminal move in the direction of arrow 45b.

[0078] Fig. 17(2) is a diagram showing a state where the power tool is connected to the main body side terminal of the conventional power tool main body 1. Two pairs of arms 205, 206 and arms 225A, 226A are fitted to the positive input terminal 22 on the power tool main body 1. Here, the position of the contact part of the arms 205, 206 and the position of the contact part of the arms 225A, 226A are separated by a distance L in the front-rear direction. However, since the size of the contact part or contact area is equal between the arms 205, 206 and the fitting part of the arms 225A, 226A, a good conductive state can be achieved as in the first embodiment.

[0079] FIG. 18 is a perspective view showing the shape of the terminal part on the electric power tool main body 30A side according to the fifth modified example of this embodiment. In the fifth modified example, the positions of the positive electrode terminal and the negative electrode terminal in the first embodiment and the position of the short bar are reversed upside down. Here, the upper positive electrode terminal 162 and the upper negative electrode terminal 167 are short-circuited by the short bar 89. The same part as the short bar 59 (see FIG. 6) in the first embodiment can be used for the short bar 89, and it is sufficient to cast it into the synthetic resin base of the terminal part of the electric power tool main body. The positive electrode input terminal 82 is similar to the positive electrode input terminal 52 (see FIG. 6) in the first embodiment in that it is composed of a terminal part 82a, a connecting part 82b, and a wiring terminal part 82c. However, since the position of the wiring terminal part 82c has to be on the rear side instead of the upper surface of the terminal part, the shapes of the connecting part 82b and the wiring terminal part 82c are changed. Similarly, the position of the wiring terminal part 87c in the negative electrode input terminal 87 is different. In accordance with shifting the positions of the positive input terminal 82 and the negative input terminal 87 in the terminal section, the connection state between the upper cell unit 146 and the lower cell unit 147 is also changed. That is, the upper cell unit 146 is connected to the lower positive electrode terminal 172 and the upper negative electrode terminal 167, and the lower cell unit 147 is connected to the upper positive electrode terminal 162 and the lower negative electrode terminal 177.

[0080] As described above, even if the position of the short bar 89 is changed, the battery pack with the automatic voltage switching mechanism of this embodiment can be realized. By adopting this configuration, the wiring terminals 82c, 87c can be attached to the rear side of the terminal section instead of being extended to the upper side (see FIG. 7), which increases the degree of freedom in designing the terminal section on the power tool body. The function of the short bar 89 can be achieved by having terminal section 89b and terminal section 89c and shorting these, so there is no need to connect the connection section 89a with a metal plate, and it may be realized by any other method that can form an electrical connection relationship with a conductive member, such as connection with a lead wire or connection with a fuse element.

[0081] FIG. 19 is a circuit diagram showing a state in which the battery pack 100 of this embodiment is connected to a conventional electric power tool main body 1. The conventional electric power tool main body 1 includes a positive input terminal 22 on the device side, a negative input terminal 27, and an LD terminal 28. A trigger switch 4 and a DC motor 5 are connected between the positive input terminal 22 and the negative input terminal 27. A semiconductor switching element M101 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. The gate of the switching element M101 is connected to the LD terminal 28 via a resistor R102. Usually, the LD terminal 28 on the battery pack 100 side is in a high impedance state. In that case, a positive voltage is applied to the gate of the switching element M101 via the resistor R101, and the switching element M101 is in a conductive state. At this time, when the LD terminal 168 is dropped to the ground potential by the discharge inhibition signal 341 from the battery pack 100 side, the gate potential of the switching element M101 becomes a voltage obtained by dividing the voltage of the positive input terminal 22 by the resistors R101 and R102, and this divided potential becomes a potential that cuts off the source-drain of the switching element M101. As a result, the power supply path to the motor 5 is cut off, and the rotation of the motor 5 stops. This switching of the potential 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 predetermined value, that is, when the battery cell is in a so-called over-discharge state, 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. The discharge inhibition signal 341 is an example of a "control signal" in the present invention, and the LD terminal 168 is an example of a "signal terminal" in the present invention.

[0082] As shown in FIG. 4, the battery pack 100 is configured to have an upper positive electrode terminal (upper +) 162, a lower positive electrode terminal (lower +) 172, an upper negative electrode terminal (upper -) 167, and a lower negative electrode terminal (lower -) 177. In addition, the battery pack 100 has an LD terminal 168 as a signal terminal. In addition to these, the battery pack 100 is provided with other signal terminals (T terminal 164, V terminal 165, LS terminal 166), but these are not shown here. The output of the upper cell unit 146 is connected to the upper positive electrode terminal 162 and the lower negative electrode terminal 177. That is, the positive electrode (+ output) of the upper cell unit 146 is connected to the upper positive electrode terminal 162, and the negative electrode (- output) of the upper cell unit 146 is connected to the lower negative electrode terminal 177. Similarly, the positive electrode (+ output) of the lower cell unit 147 is connected to the lower positive electrode terminal 172 , and the negative electrode (− output) of the lower cell unit 147 is connected to the upper negative electrode terminal 167 .

[0083] The upper cell unit 146 and the lower cell unit 147 are each formed by connecting five lithium-ion battery cells in series. A protection IC 300 for monitoring the voltage of the battery cells, a protection IC 320, and a control unit 350 are connected to the upper cell unit 146 and the lower cell unit 147. The protection IC 300 is an integrated circuit commercially available as a "lithium-ion battery protection IC" that performs overcharge protection and overdischarge protection functions as well as cell balancing, cascade connection, and open circuit detection functions by inputting the voltage across each battery cell of the upper cell unit 146. The protection IC 300 has a built-in power supply circuit that obtains operating power for the protection IC from the voltage of the upper cell unit 146. In addition, if the voltage of the battery cell of the upper cell unit 146 drops below a predetermined value and enters an over-discharged state, the protection IC 300 outputs a signal (high signal) 305 indicating over-discharge to the control unit 350, and if the voltage of the battery cell of the upper cell unit 146 reaches or exceeds a predetermined value during charging and enters an over-charged state, the protection IC 300 outputs a signal (high signal) 306 indicating over-charge to the control unit 350.

[0084] A protection IC 320 is connected to the lower cell unit 147. Here, a control unit 350 is further provided in the circuit of the lower cell unit 147, i.e., in the circuit between the lower positive terminal 172 and the upper negative terminal 167. That is, while the protection circuit provided in parallel with the upper cell unit 146 is composed of only the protection IC 300, the protection circuit provided in parallel with the lower cell unit 147 is composed of the protection IC 320 and the control unit 350. The control unit 350 includes an MCU (Micro Controller Unit, so-called "microcomputer"). The control unit 350 receives the output (overdischarge signal 305, overcharge signal 306) from the protection IC 300, the output (overdischarge signal 325, overcharge signal 326) from the protection IC 320, and a signal from the cell temperature detection means 331. The microcomputer of the control unit 350 includes a voltage detection circuit, for example, called an analog front end (AFE), and measures the current value flowing from the output voltage of the current detection circuit 327 to the lower cell unit 147. The power supply for driving the control unit 350 is generated by a power supply circuit 321 connected to the lower cell unit 147, and the power supply voltage (VDD1) is supplied to the control unit 350. Each of the protection IC 300, the protection IC 320, and the control unit 350 is an example of a "protection circuit" in the present invention. The protection circuit is directly connected to any of the cell units or indirectly connected via another protection circuit, monitors the state of the battery cells that constitute the cell unit, and outputs a signal according to the state of the battery cell. A circuit combining any of the protection IC 300, the protection IC 320, and the control unit 350 is also an example of a "protection circuit" in the present invention. The protection IC 300 is an example of a "first protection circuit" in the present invention, the protection IC 320 is an example of a "second protection circuit" in the present invention, and the control unit 350 is an example of a "control unit" in the present invention. The control unit is connected directly to any one of the cell units, or indirectly to the cell units via another protection circuit. The power supply circuit 321 is an example of the "power supply circuit" in the present invention, and the power supply voltage (VDD1) is an example of the "power supply voltage" in the present invention.Furthermore, the cell temperature detection means 331 is an example of a "detection unit" and a "temperature detection unit" in the present invention, the current detection circuit 327 is an example of a "detection unit" and a "current detection unit" in the present invention, and the temperature detected by the cell temperature detection means 331 and the current detected by the current detection circuit 327 are each an example of a "physical quantity" in the present invention.

[0085] A shunt resistor 329 is provided on the ground side of the lower cell unit 147, but no shunt resistor is provided on the upper cell unit 146 side. This is because when the upper cell unit 146 and the lower cell unit 147 are connected in series, the current value can be measured using only the shunt resistor 329. On the other hand, when the upper cell unit 146 and the lower cell unit 147 are connected in parallel, the actual current value on the upper cell unit 146 side cannot be measured. However, the control unit 350 can monitor the current value of the upper cell unit 146 assuming that it is equal to that of the lower cell unit 147. It is also possible to provide a shunt resistor and a voltage detection circuit on the ground side of the upper cell unit 146, and to directly monitor the current value on the lower cell unit 147 side using the microcomputer of the control unit 350.

[0086] The control unit 350 monitors the current value and cell temperature, and also monitors the states of the upper cell unit 146 and the lower cell unit 147 to control the operation of both in an integrated manner. When an emergency stop of the power tool main body 1 is required, the control unit 350 issues a discharge inhibition signal 341 to change the potential of the LD terminal 168, thereby stopping the operation of the power tool main body 1 via the LD terminal 28. The most important thing monitored by the control unit 350 is the amount of current flowing through the battery cells included in the upper cell unit 146 and the lower cell unit 147. In recent power tools, the performance of the battery cells has improved and the capacity has increased, making it possible to extract a large current from the battery pack 100. However, in terms of life and heat generation, it is preferable to limit the current flowing through the battery cells to a predetermined amount (less than the upper current limit value). Therefore, in order to particularly monitor the current flowing through the battery cells, the control unit 350 monitors the current value using a shunt resistor 329 and a current detection circuit 327 interposed in the power supply line of the lower cell unit 147.

[0087] The protection circuit for managing the lower cell unit 147, which is composed of the protection IC 320, the control unit 350, the power circuit 321, the current detection circuit 327, etc., may be integrated into one chip and configured as a "battery management IC." On the other hand, the protection IC 300 for the upper cell unit 146 may be the same as that widely used in the conventional battery pack 15 (see FIG. 1), and is commercially available as a "battery protection IC" for 5 cells. The operation of the protection IC 320 is almost the same as that of the protection IC 300, and when it detects that the voltage of the battery cell in the lower cell unit 147 has dropped to a predetermined lower limit (overdischarge state), it sends an overdischarge signal 325 to the control unit 350. Also, when the battery pack 100 is attached to an external charging device (not shown) and charging is being performed, the protection IC 320 sends an overcharge signal 326 indicating an overcharge state to the control unit 350 when it detects that the voltage of the battery cell has exceeded a predetermined upper limit. The control unit 350 sends a charging stop signal to a charging device (not shown) via the LS terminal 166 (see FIG. 4). As described above, the upper cell unit 146 and the lower cell unit 147 are each equipped with a protection circuit for the battery cells, so that the batteries can be protected by detailed battery monitoring.

[0088] In this embodiment, the protection circuit of the upper cell unit 146 includes only the protection IC 300 and does not include a microcomputer, whereas the protection circuit of the lower cell unit 147 includes a control unit 350 including a microcomputer in addition to the protection IC 320. The power supply circuit 321 generates power for the operation of the control unit 350 using the power of the lower cell unit 147. Since the battery pack 100 of this embodiment is a voltage switching type of 18V and 36V, if a microcomputer is installed in the protection circuit on the upper cell unit 146 side, the ground potential of the control unit 350 will change when the two cell units are connected in series and when they are connected in parallel. On the other hand, if the power supply circuit 321 is installed on the lower side, the ground potential of the power supply circuit 321 will not change. Therefore, in this embodiment, the control unit 350 equipped with a microcomputer is installed in the circuit of the lower cell unit 147, not in the circuit of the upper cell unit 146. This arrangement of the microcomputer allows the control unit 350 including a microcomputer to operate stably even when the output voltage is switched between rated 18V and 36V. The ground potential of the control unit 350 corresponds to the "ground potential of the control unit" in this invention.

[0089] If the control unit 350 including a microcomputer is provided only in the circuit of one of the cell units, the problem of imbalance in power consumption between the two cell units will occur. Although the power consumption by the control unit 350 is very small, the power consumption on the lower cell unit 147 side will be greater than the power consumption on the upper cell unit 146 side. It is not desirable for the power consumption imbalance to continue for a long time, because the potential on the lower cell unit 147 side will be lower than that of the upper cell unit 146. In particular, when the upper cell unit 146 and the lower cell unit 147 are connected in parallel to output a rated voltage of 18V, a circulating current will flow due to the voltage imbalance between the cell units immediately after the parallel connection state is established. Therefore, in this embodiment, a current consumption control means 310 is provided in the circuit of the upper cell unit 146, which consumes less power, and has the function of adjusting the amount of current consumption with the lower cell unit 147. The current consumption control means 310 is disposed in parallel with the one of the two cell units consuming less power, in this case the upper cell unit 146, and is mounted on the circuit board 150 (see FIG. 4) as a load circuit separate from the integrated protection IC 300. The current consumption control means 310 is an example of the "current consumption control section" of the present invention.

[0090] The current consumption control means 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 (VDD1) applied to itself, and has a normal operating state (normal mode) and an operation stop state (so-called sleep state). While the microcomputer of the control unit 350 holds the power supply voltage VDD1, the protection IC 300 is also put into an operating state by switching the state of the start terminal 301 used as a control signal. In this embodiment, the circuit of the current consumption control means 310 is devised so that when the microcomputer of the control unit 350 holds the power supply voltage VDD1, a current for adjusting power consumption flows to the current consumption control means 310 in conjunction with the control unit 350, and the current consumption control means 310 switches the state of the start terminal 301. As a result, when the control unit 350 starts up, the protection IC 300 also starts up in conjunction with 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 starts up, the protection IC 320 also starts up at the same time. The current consumption control means 310 causes the cell set to which the control unit 350 is connected (lower cell unit 147) to consume the same current as the other cell set (upper cell unit 146).

[0091] The current consumption control means 310 is an electric circuit including a plurality of switching elements M31 to M33 such as FETs and a plurality of resistors (resistors R31 to R35). In the basic circuit configuration, a series connection of resistors R31 and R34, which serve as two pseudo loads, is connected between both terminals of the upper cell unit 146, and the circuit is switched on and off by the switching element M32. The source terminal of the switching element M32 is connected to the positive electrode of the upper cell unit 146, and the drain terminal is connected to the resistor R31. The gate terminal of the switching 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 switching element M32, and the other end is connected to the gate terminal of the switching element M32. One end of the resistor R35 is connected to the gate terminal of the switching element M32, and the other end is connected to the drain terminal of the switching element M33. The switching element M33 is switched on or off in conjunction with the power supply voltage VDD1 by inputting the power supply voltage (VDD1) of the microcomputer included in the control unit 350 to the gate signal. The source terminal of the switching element M33 is grounded, and a resistor R33 is connected between the source terminal and the gate terminal of the switching element M33. The resistor R33 is provided so that the switching element M33 is stably switched by the voltage change of the gate signal. In such a current consumption control means 310, when the power supply voltage VDD1 of the microcomputer is on, the gate potential of the switching element M33 is VDD1 (high level), and when the power supply voltage VDD1 is off, the gate potential of the switching element M33 is 0V (low level). The same signal as the gate signal of the switching element M33 is also input to the protection IC 320. Then, the switching element M33 is in the OFF state. When switching element M33 is in the OFF state, switching element M32 is also in the OFF state, and therefore the current path to the dummy load side by resistors R31 and R34 is cut off, resulting in zero power consumption by current consumption control means 310. To ensure that protection IC 300 is also turned off in this state, a switching element M31 is further provided that inputs the potential at the connection point of resistors R31 and R34 as a gate signal (operation signal 302).The drain terminal of the switching element M31 is connected to a start terminal 301 of an internal power supply (not shown) of the protection IC 300, and the source terminal is connected to the negative electrode of the upper cell unit 146. The operation signal 302 is a signal indicating the operation state of the current consumption control means 310, and when it is at a high level, it indicates that the current consumption control means 310 is operating, that is, the microcomputer of the control unit 350 is also operating. On the other hand, when the current consumption control means 310 is not operating, that is, the microcomputer of the control unit 350 is stopped, the operation signal 302 goes low and the start terminal 301 goes into a high impedance state, so that the protection IC 300 stops.

[0092] The potential of the negative electrode of the upper cell unit 146 (reference potential A) 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 electrode 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, so the switching element M31 is turned off, and the start terminal 301 is in a high impedance state where it is not connected. On the other hand, when the switching element M32 is turned on and current flows through the pseudo load, the divided voltage of the resistors R31 and R32 is applied to the gate terminal of the switching element M31, so that the switching element M31 is turned on. Then, the start terminal 301 is connected to the reference potential A, so that power is supplied to the built-in power supply in the protection IC 300, and the protection IC 300 starts up. With the above-mentioned connection configuration, the power consumption of the microcomputer of the control unit 350 on the lower cell unit 147 side can be consumed in the circuit of the upper cell unit 146 by the current consumption control means 310. Furthermore, the start and stop control of the protection IC 300 itself can also be performed in response to switching the current consumption control means 310 between operation and stop. Therefore, the microcomputer of the control unit 350 can control the start and stop of the protection circuit of the lower cell unit 147 and the protection circuit of the upper cell unit 146 in conjunction with each other.

[0093] The state of the microcomputer of the control unit 350 has three stages: normal, sleep, and shutdown. In normal, the microcomputer is always active. In sleep, the microcomputer is activated intermittently by itself, and the operation of activating for 50 milliseconds and then stopping for 5 seconds is repeated. In shutdown, the power supply voltage VDD1 is not supplied at all, and the microcomputer is completely stopped. The microcomputer operates whether the battery pack 100 is attached to the power tool main body 1 or not. However, when the battery pack 100 is not attached, or when the power tool is not used for a certain period of time even when the battery pack 100 is attached, for example, when the trigger operation is not performed for about two hours after the trigger operation is ended, the microcomputer goes into sleep state. Even in this sleep state, the current consumption control means 310 operates in conjunction with the activation of the microcomputer, and the protection IC 300 is also activated via the current consumption control means 310. When the trigger switch 4 of the power tool body 1 is pulled and a 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 the normal state.

[0094] In this embodiment, when a microcomputer is included in only one of the protection circuits of multiple cell units, the increase in potential difference between multiple cell units caused by leaving the battery pack removed for a long period of time is solved by adding a current consumption control means 310 that consumes power equivalent to that of a microcomputer to the protection circuits of the other cell units that do not have a microcomputer.This makes it possible to adjust the balance of current consumption for each of the multiple cell units, and realizes a battery pack in which the voltage balance between the cell units does not deteriorate even after long-term storage.

[0095] The battery pack 100 is provided with a remaining capacity display means 335 for displaying the remaining battery capacity, and when the remaining capacity display switch 190 (see FIG. 4) is pressed, the remaining battery capacity is displayed by the number of light-emitting diodes (not shown) that light up. Although not shown here, a signal from the remaining capacity display switch 190 is input to the control unit 350, and the microcomputer of the control unit 350 controls the lighting of the light-emitting diodes of the remaining capacity display means 335. The remaining battery capacity displayed by the remaining capacity display means 335 may be displayed based on the voltage across either one of the upper cell unit 146 or the lower cell unit 147, or may be displayed based on the lowest voltage value among the ten battery cells.

[0096] The output of the upper voltage detection circuit 322 connected to the upper positive terminal 162 is input to the control unit 350. This output indicates the potential of the upper cell unit 146 when the battery pack 100 is not attached to the power tool main body 1, 30 or an external charging device (not shown). On the other hand, when the battery pack 100 is attached to the power tool main body 1 for low voltage (18V), the upper positive terminal 162 and the lower positive terminal 172 are connected, so that the positive electrodes of the upper cell unit 146 and the lower cell unit 147 have the same potential, and the negative electrodes of the upper cell unit 146 and the lower cell unit 147 have the same potential. Therefore, the microcomputer included in the control unit 350 can determine whether the battery pack 100 is not attached, is attached to a low-voltage device main body, or is attached to a high-voltage device by comparing the potential of the upper positive terminal 162 and the potential of the lower positive terminal 172. In order to detect the potential of the lower positive terminal 172, it is preferable to configure the control unit 350 to acquire the positive potential of the uppermost battery cell 147a among the battery cells in the lower cell unit 147. In this way, the microcomputer provided in the circuit of the lower cell unit 147 can determine whether the upper cell unit 146 and the lower cell unit 147 of the battery pack 100 are connected in series (attached to a 36V device) or in parallel (attached to an 18V device). In this way, the microcomputer can also monitor the voltage value on the upper cell unit 146 side that exceeds the range of the power supply voltage acquired (the voltage in the lower cell unit 147), so that it can determine the connection state of the voltage switching type battery pack 100 and perform optimal control according to the determined connection state. The upper voltage detection circuit 322 is an example of the "detection unit" and "first voltage detection unit" in the present invention, and the potential of the upper cell unit 146 is an example of the "physical quantity" and "voltage of the first cell unit" in the present invention.

[0097] The LD terminal 168 is a terminal for transmitting a signal from the battery pack 100 side for stopping the power tool main body 1 or a signal for stopping the operation of an electric device powered by the battery pack (not shown). 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 switching element M41 from a normal low state ("discharge permission from the battery pack 100") to a high state ("discharge inhibition from the battery pack 100"). The switching element M41 is, for example, a P-type field effect transistor (FET), with the drain side connected to the LD terminal 168 and the source side grounded. Therefore, in the normal state of the switching element M41 (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 main body 1 side. On the other hand, when the discharge inhibition signal 341 is switched to high by the control of the control unit 350, the source-drain of the switching element M41 is grounded by conduction, so that the potential of the LD terminal 28 on the power tool main body 1 side falls to the ground potential. As a result, the gate potential of the switching element M101 on the power tool main body 1 side, that is, the divided potential by the voltage dividing resistors R101 and R102, drops, so that the source-drain of the switching element M101 becomes non-conductive, the power circuit of the power tool main body 1 is cut off, and the rotation of the motor 5 is prevented. In this way, the discharge inhibition signal 341 generated by the control unit 350 of the battery pack 100 can prevent the rotation of the motor 5 of the power tool main body 1. Therefore, the control unit 350 can quickly stop the operation of the power tool or electrical equipment when a situation occurs in which it is necessary to stop the power supply from the battery pack 100, such as an excessive current during discharge, a drop in cell voltage during discharge (overdischarge), or an abnormal rise in cell temperature (overtemperature), and the like, and thus it is possible to protect not only the battery pack 100 but also the power tool main body 1.

[0098] FIG. 20 is a circuit diagram of the battery pack 100 of this embodiment, showing the state of connection to an 18V electric power tool main body 1A with a main body-side microcomputer. Here, the internal configuration of the battery pack 100 side is completely the same as that shown in FIG. 19, and only the configuration of the electric power tool main body 1A side is different. The electric power tool main body 1 side shown in FIG. 19 does not include a microcomputer. However, in recent electric power tools, the use of a control unit 60 having a microcomputer for controlling the motor 5 has been increasing. The electric power tool main body 1A includes a power supply circuit 61, and the control unit 60 operates with a constant low voltage (reference voltage VDD2) generated by the power supply circuit 61. The control unit 60 includes a microcomputer, and monitors and controls various states within the electric power tool main body 1A by the microcomputer. The control unit 60 is connected to the output of a battery voltage detection circuit 62 and a switch state detection circuit 63 that outputs a high or low signal depending on the connection state of the trigger switch 34. In this embodiment, a DC motor 35 is provided in a power supply path between the positive input terminal 22 and the negative input terminal 27, and an operation switch 34 (trigger switch) for turning on or off the rotation of the motor 35 is provided in the circuit. 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 a current detection circuit 64, and the value is output to the control unit 60. In this circuit diagram, the motor 35 is illustrated as a brushed DC motor, but a configuration in which a three-phase brushless motor is driven using a known inverter circuit may also be used. In that case, the switching element M101 may be connected in series in the power path input to an inverter circuit (not shown), or the control unit 60 may stop the rotation of the motor 35 by controlling a switching element (not shown) included in the inverter circuit instead of the switching element M101.

[0099] The LD terminal 28 of the power tool main body 1A is connected to the control unit 60 via a resistor R112. A reference voltage VDD2 is further connected to the control unit 60 side of the resistor R112 via a resistor R113. Therefore, when the LD terminal 28 is in a high impedance state, a voltage close to VDD2 is applied to the input line 65 of the control unit 60, and when the LD terminal 28 falls to the ground potential, a divided voltage of the resistors R113 and R112, i.e., a voltage significantly lower than the reference voltage VDD2, is transmitted to the input port of the control unit 60 via the input line 65. The control unit 60 detects a change in the potential of this input line 65 and controls the gate signal of the switching element M101 to allow or stop the power supply to the motor 35.

[0100] In this way, the power tool main body 1A is provided with a circuit for stopping the motor 35 in accordance with the discharge inhibition signal input via the LD terminals 168 and 28. However, when the power tool main body 1A has the control unit 60, it is preferable that the control unit 350 on the battery pack 100 monitors the overcurrent and stops the motor 5 on the power tool main body 1A, and that the control unit 60 on the power tool main body 1A directly monitors the overcurrent using the current detection circuit 64. When the control unit 350 on the battery pack 100 monitors the overcurrent, it is necessary to set an average control condition (threshold value of overcurrent) that can be applied to a plurality of power tool main bodies. However, when the control unit 60 on the power tool main body 1A monitors the overcurrent, it is possible to set the optimal control condition (higher threshold value of overcurrent) for the power tool main body 1A, and therefore it is possible to avoid the output restriction of the power tool caused by the control unit 350 setting the average control condition (lower threshold value of overcurrent). This avoidance of output limitations is particularly effective in new power tools that will be released in the future, and allows control that makes the most of the capabilities of the new power tool body 1A.

[0101] In this embodiment, the control unit 350 on the battery pack 100 side judges whether or not the power tool main body 1 or 1A side to which the battery pack 100 is attached includes a control unit 60 having a microcomputer, and changes the condition for overload protection on the battery pack 100 side according to the judgment result. Specifically, when the power tool main body 1 side does not include a microcomputer as shown in FIG. 19, the overcurrent limit value at the time of low voltage output is set to a threshold value for the power tool main body 1A without a microcomputer, for example, 20A (default value). The default value may be appropriately set according to the capacity and performance of the battery cell used. This overcurrent limit value is set to the same value as that set in the conventional battery pack 15, so that the conventional power tool main body 1A without a microcomputer can be driven using the battery pack 100 of this embodiment. On the other hand, when the power tool main body 1A side includes a microcomputer, the overcurrent limit value at the time of low voltage output is not set on the battery pack 100 side, and the monitoring of the overcurrent value is left to the microcomputer of the control unit 60 on the power tool main body 1A side. As a result, the control unit 60 can optimally monitor the current according to the characteristics of the motor 5 used and the structural characteristics of the power tool main body 1A, and the like, and it is possible to avoid a problem in which the power tool main body 1A cannot effectively utilize its capabilities due to excessively restricting the overcurrent limit value on the battery pack 100 side. Also, the power tool main body 1A can realize a high-output power tool by making the most of the capabilities of the battery pack 100. Changing the conditions for overload protection on the battery pack 100 side between the low-voltage side and the high-voltage side in this way means that the control unit 60 on the power tool main body side can provide optimal overload protection for the power tool main body 1A while leaving room for further improvements and higher output of low-voltage power tools that will be newly sold in the future.

[0102] In order to determine whether the power tool main body 1 or 1A includes a control unit 60 having a microcomputer, an LD terminal voltage detection circuit 328 for detecting the voltage value applied to the LD terminal 28 is newly provided in the battery pack 100. The LD terminal voltage detection circuit 328 is connected to the LD terminal 168 by a connection line 342, and outputs an output according to the terminal voltage to the control unit 350. The microcomputer included in the control unit 350 measures the LD terminal voltage after the battery pack 100 is attached and when the discharge inhibition signal 341 is not being generated, thereby determining whether the power tool main body includes the control unit 60 having a microcomputer. In the case of a power tool main body 1 that does not include a microcomputer, as can be seen from the circuit diagram of FIG. 19, the LD terminal 28 is in a state in which a voltage substantially equal to that of the positive input terminal 22 is applied thereto. The microcomputer of the control unit 350 detects the voltage of the upper positive terminal 162 by the upper voltage detection circuit 322, and can determine whether or not the power tool main body 1 includes a microcomputer by comparing the voltage of the upper positive terminal 162 with the LD terminal voltage. On the other hand, as can be seen from the circuit diagram of FIG. 20, in the case of the power tool main body 1A having a microcomputer, a voltage substantially equal to the reference voltage VDD2 (for example, 5V or 3.3V) for driving the microcomputer is applied to the LD terminal 28. Therefore, the microcomputer of the control unit 350 can easily determine that the power tool main body 1A includes a microcomputer by only detecting the LD terminal voltage, without having to compare it with the voltage of the upper positive terminal 162 by the upper voltage detection circuit 322. As described above, by providing the connection line 342 and the LD terminal voltage detection circuit 328 in the battery pack 100, the control unit 350 can easily determine whether the power tool main body or the electric device main body is an electronic control compatible tool including a low-voltage control unit such as a microcomputer, or a non-compatible tool. Furthermore, depending on the judgment result, the control unit 350 can change the control parameters for monitoring the battery cells, for example, the overload protection conditions. Here, the values ​​of the control parameters to be changed can be stored in advance in a non-volatile memory included in the microcomputer, and one of the stored values ​​can be read out and set depending on the judgment result.The LD terminal voltage detection circuit 328 is an example of the "detection section" and the "second voltage detection section" in the present invention, and the voltage of the LD terminal 168 is an example of the "physical quantity" in the present invention.

[0103] 21 is a circuit diagram of the electric power tool body 30 capable of handling high loads with the battery pack 100 attached thereto. The electric power tool body 30 capable of handling high loads is characterized in that it has device-side terminals (positive input terminal 52, negative input terminal 57, and terminals 59b and 59c of the short bar) corresponding to the positive terminals (162, 172) and negative terminals (167, 177) of the battery pack 100, respectively. The short bar 59 is a metal part having a terminal 59b on one side and a terminal 59c on the other side, and when the battery pack 100 is attached to the electric power tool body 30, the lower positive terminal 172 and the lower negative terminal 177 are short-circuited by the short bar 59. The positive input terminal 52 of the electric power 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 main body terminals divided into two parts in this way, it is possible to obtain an output by connecting the upper cell unit 146 and the lower cell unit 147 in series, that is, a rated voltage of 36 V. The configuration of the power tool main body 30 is almost the same as the internal configuration of the power tool main body 1A shown in FIG. 20. The motor 45 is a motor for a rated voltage of 36 V, but a brushless DC motor may be driven using an inverter circuit, as in the motor 35 shown in FIG. 20. A switching element M101 is provided in series with a power circuit to the motor 45. The switching element M101 is controlled to be turned on or off by a gate signal output from the control unit 60, and the rotation of the motor 45 is stopped by turning off the switching element M101. In the high-voltage power tool main body 30, the procedure for sending the discharge inhibition signal 341 from the battery pack 100 is exactly the same as the circuits shown in FIG. 19 and FIG. 20. That is, when the source-drain of the switching element M41 is brought into conduction under the control of the control unit 350 on the battery pack 100 side and the LD terminal 168 is dropped to ground potential, this state is transmitted to the input port of the microcomputer included in the control unit 60, and the control unit 60 can detect it as a discharge inhibition signal from the battery pack 100 side.However, in the 36V power tool main body 30, the control of discharging prohibition due to overcurrent is performed by the control unit 60 on the tool main body side, and the battery pack 100 side is not involved in monitoring the overcurrent, or the threshold value for stopping due to overcurrent is set sufficiently high, close to the limit value of the battery cell, so that the microcomputer of the control unit 350 does not actually have to be involved in monitoring the current value. As a result, it is possible to satisfactorily achieve both further increase in output of the battery pack 100 and maintenance of compatibility with the conventional battery pack 15.

[0104] Next, the procedure for outputting a discharge inhibition signal by the control unit 350 of the battery pack 100 will be described with reference to FIG. 22. The series of procedures shown in FIG. 22 can be executed by the microcomputer in the form of software using a program previously stored in the control unit 350, and are executed automatically when the battery pack 100 is started up. First, the microcomputer determines whether the connected power tool body is a low-voltage (18V) device or a high-voltage (36V) device, thereby determining whether the upper cell unit 146 and the lower cell unit 147 of the battery pack 100 are connected in parallel or in series (step 371). In the case of a series connection, the control parameters for the control unit 350 are set for a series connection (step 372). In the case of a parallel connection, the control parameters for a parallel connection are set (step 373). Here, the control parameters may be, for example, a current limit value I max , the upper limit of cell voltage during charging V max , the lower limit of cell voltage during discharge V min , the upper limit of the cell temperature T max Here, the discharge current limit value I max is set to 20A, and the current limit value I max Set to no limit (no limit value) or to a value significantly larger than that for parallel connection (for example, 40 to 80 A). max The lower limit of cell voltage during discharge, V, is 80°C regardless of whether the cells are connected in series or parallel. min is 2.5V / cell regardless of series or parallel connection.

[0105] Next, the microcomputer determines a predetermined cell voltage lower limit V min It is determined whether there is a battery cell that is equal to or lower than the cell voltage lower limit V min Proceed to step 378 if the following exists: All cell voltages are below the lower cell voltage limit V min If it is greater than the cell voltage lower limit V, it is next determined whether the over-discharge signal 305 from the protection IC 300 is high (step 375). The over-discharge signal is high when any of the battery cells in the upper cell unit 146 is below the cell voltage lower limit V min Since this means that the peak current is below the threshold value I1, in this case the process proceeds to step 378. If the answer is No in step 375, it is determined whether the peak current value detected by the current detection circuit 327 is equal to or greater than a predetermined threshold value I1 (step 376). The detection of the peak current value I may be performed by simply monitoring the instantaneous value of the peak current, or by dividing a certain time window and detecting the average current within that time window to eliminate the influence of a current that protrudes like a steeple. Note that when the upper cell unit 146 and the lower cell unit 147 are connected in series and the cell current limit value I max If not set, step 376 is skipped and the process proceeds to step 377.

[0106] Next, it is determined whether the battery temperature detected by the cell temperature detection means 331 is equal to or higher than a predetermined threshold value T1 (step 377). Here, thermistors TH1 and TH2 are provided in both the upper cell unit 146 and the lower cell unit 147 to measure the temperature, and if either temperature is equal to or higher than the threshold value T1, the process proceeds to step 378. If both temperatures are lower than the threshold value T1 in step 377, the process returns to step 371, and if they are equal to or higher than the threshold value T1, the microcomputer of the control unit 350 sends a discharge inhibition signal 341 to stop the motors 5, 35, and 45 of the power tool main body 1, 1A, and 30, turns on the switching element M41, drops the LD terminal 168 to ground potential, and then returns to step 371 (step 378). By repeating the above procedure, the control unit 350 can monitor the state of the battery cells and, if necessary, stop the operation of the power tool or electrical equipment to which the battery pack 100 is attached by the discharge inhibition signal 341.

[0107] Next, the specific circuit configuration of the remaining capacity display means 335 and the upper voltage detection circuit 322 of the battery pack 100 will be described with reference to FIG. 23. FIG. 23 shows in detail the configuration of the remaining capacity display means 335 and the components of the upper voltage detection circuit 322, and the other configurations of the battery pack 100 side are the same as those of the battery pack 100 in FIG. 19 to FIG. 21. The microcomputer of the control unit 350 has an input / output port (Input Output Port) group 353, four of which are connected to the light-emitting diodes LD0 to LD3 in the remaining capacity display means 335. In addition, a switching element M0 is provided between the power supply voltage VDD1 and each of the light-emitting diodes LD0 to LD3 in the remaining capacity display means 335, and one of the four input / output ports IO0 is connected to the gate. In addition, the other one (IO3) of the four input / output ports is connected to the gate terminal of the switching element M3. The switching element M3 is used for controlling the connection or disconnection between the source and drain of the switching element M4.

[0108] The basic configuration of the upper voltage detection circuit 322 is composed of resistors R6 and R7, and the intermediate potential between them is input to the input port AN0 of the control unit 350 as the voltage of the upper cell unit 146 (upper voltage detection). A switching element M4 made of an FET is interposed between the resistor R6 and the upper positive terminal 162. The gate terminal of the switching element M4 is connected to the drain terminal of the switching element M3, which is controlled to be turned on and off by the input / output port IO3. In other words, when the light-emitting diode LD3 is turned off, if the input / output port IO3 is turned off, the switching element M3 is turned off, and the gate potential of the switching element M4 remains high, so that the source-drain of the switching element M4 is conductive (on), and the upper voltage detection is input to the input port AN0 of the microcomputer. The input port group 352 (AN0, AN1, etc.) has an A / D conversion function that converts an input analog signal into a digital signal. On the other hand, when IO3 is set to high to light the light emitting diode LD3, the switching element M3 is turned on, and the gate terminal of the switching element M4 falls to the ground potential, cutting off (turning off) the source-drain of the switching element M4. By connecting as described above, the control unit 350 can detect the voltage of the upper positive terminal 162 using the input port AN0.

[0109] As described above, the control unit 350 requires a total of three ports, including the input port AN0 for inputting the voltage of the upper positive terminal 162, and two input ports AN1 and AN2 for inputting the output of the cell temperature detection means 331. The cell temperature detection means 331 includes two thermistors: the thermistor TH1 for measuring the temperature of the upper cell unit 146, and the thermistor TH2 for measuring the temperature of the lower cell unit 147. However, preparing a microcontroller with three input ports AN0 to AN2 for inputting the voltage of the upper positive terminal 162, the output of the thermistor TH1, and the output of thermistor TH2 would increase the cost of the microcontroller and increase the chip size. Therefore, the configuration of FIG. 24 is devised so that these three inputs are shared by one input port AN0.

[0110] FIG. 24 is an input / output circuit diagram of a microcomputer 351 in the control unit 350. In FIG. 24, the microcomputer 351 has an input port group 352 and an input / output port group 353. The input port group 352 has a function of converting an input analog signal into a digital signal, and one of the input ports, an input port AN1, is connected for inputting signals from thermistors TH1 and TH2 and the upper voltage detection circuit 322A. The input / output port (Input Output Port) group 353 is an input / output port that serves both as an input port and an output port, and here, four input / output ports IO0 to IO3 are connected to light-emitting diodes (LD0 to LD3). A switching element M0 for controlling the ON / OFF of the supply of power (VDD1) to the light-emitting diodes LD0 to LD3 is connected to the input / output port IO0. A resistor R5 is connected between the gate and source of the switching element M0, and the switching element M0 and the resistor R5 form a switching means 364 for controlling the turning on and off of the light-emitting diodes LD0 to LD3. The input / output ports IO1 to IO3 are connected to the light emitting diodes LD1 to LD3 and also to the gate terminals of the switching elements M1 to M3, respectively.

[0111] The two thermistors TH1 and TH2 have one terminal connected to the reference voltage VDD1 of the microcomputer 351 via a common resistor Ra, and the other terminal connected to ground via the switching elements M1 and M2. The thermistors TH1 and TH2 are, for example, NTC thermistors having a characteristic that the resistance value decreases as the temperature increases, and are arranged in the vicinity of the battery cells so that the microcomputer 351 measures the temperature of the battery cells. Here, it is preferable to arrange the thermistor TH1 in the vicinity of the upper cell unit 146, and the thermistor TH2 in the vicinity of the lower cell unit 147. The switching elements M1 to M3 are semiconductor switches that can be electrically switched on and off, and the drain terminals of the switching elements M1 and M2 are connected to the other terminals of TH1 and TH2, and the source terminal is connected to ground. The drain terminal of the switching element M3 is connected to the upper voltage detection circuit 322A via a resistor Rb, and the source terminal is connected to ground. The gate terminals of these switching elements M1 to M3 are connected to the input / output ports IO1 to IO3, respectively, of the microcomputer 351, and the source terminals are grounded. Ground resistors R6 to R8 are provided between the gate terminals and source terminals of the switching elements M1 to M3, respectively, to set the voltage between the gate and source to 0 volts when the input / output ports IO1 to IO3 are open.

[0112] The four light emitting diodes LD0 to LD3 can be of any color, and green or red is used here. Resistors R0 to R3 for current limiting are connected in series in the circuit of the light emitting diodes LD0 to LD4. The resistors R0 to R3 can have the same resistance value. Here, the input / output port IO0 is commonly connected to the gate terminal of the switching element M0 and to the light emitting diode LD0. By connecting the switching element M0 and the light emitting diode LD0 in parallel to the input / output port IO0 in this way, the input / output port IO0 can be set to either high or low, and the circuit surrounded by the dotted line can be used as a switching means 364 for switching whether or not to light up all of the light emitting diodes LD0 to LD3. To light up the other light emitting diodes LD1 to LD3, the output of the input / output ports IO1 to IO3 is set to low (ground potential) while the light emitting diode LD0 is turned on.

[0113] When the light-emitting diodes LD0 to LD3 are off, the input / output ports IO1 to IO3 select one of the signals from the thermistors TH1, TH2, and the upper voltage detection circuit 322A and input it to the input port AN1. That is, by setting the input / output port IO0 to low and switching one of the outputs from the input / output ports IO1 to IO3 to high at that time, the outputs from the thermistors TH1, TH2, and the upper voltage detection circuit 322A can be selectively input to the input port AN1. Also, even when any of the light-emitting diodes LD0 to LD3 is on, if the signal from the input / output port IO0 is in a high impedance state only during the period when the microcomputer 351 acquires the outputs from the thermistors TH1, TH2, and the upper voltage detection circuit 322A, these outputs can be input sequentially to the input port AN1 in chronological order. When inputting to the input port AN1, all the light-emitting diodes LD0 to LD3 are turned off, but while they are off, temperature detection by thermistors TH1 and TH2 or voltage detection by the upper voltage detection circuit 322A is completed, and the light-emitting diodes LD0 to LD3 are returned to their original on state. That is, the following procedure is repeated: turn off the light-emitting diodes → detection by thermistor TH1 → turn on the light-emitting diodes again for a certain period of time and then turn off → detection by thermistor TH2 → turn on the light-emitting diodes again for a certain period of time and then turn off → voltage detection by the upper voltage detection circuit 322A → turn on the light-emitting diodes again. The time required for this temperature detection by thermistors TH1 and TH2 and voltage detection by the upper voltage detection circuit 322A is, for example, 1 millisecond. If these detections are performed in sequence at 50 millisecond intervals, there is a turn-on time of 49 milliseconds after the 1 millisecond when the lights are turned off, so that the three detections of temperature detection by thermistors TH1 and TH2 and voltage detection by the upper voltage detection circuit 322A can be completed in 150 milliseconds. At this time, if any of the light-emitting diodes LD0 to LD3 are turned on, the light-emitting diode will be turned off for 1 millisecond every 50 milliseconds. However, since an interval between lights being off at this interval is perceived by the human eye as being continuously on, the temporary turning off does not pose a problem.

[0114] FIG. 25 is a table showing the correspondence between the input / output ports IO0 to IO3 in FIG. 24 and the output state of each output device. The vertical axis shows the lighting state of the light-emitting diode (LED), the detection by thermistors TH1 and TH2, and the voltage detection state by the upper voltage detection circuit 322A, and the signal levels of the input / output port group 353 at that time are shown in columns 353a and 353b. Here, for example, when the battery capacity is 25 to 50%, only the light-emitting diode LD0 is turned on, when it is 50% to 75%, two light-emitting diodes LD0 and LD1 are turned on, when it is 75% to less than 100%, three light-emitting diodes LD0 to LD2 are turned on, and when it is in a fully charged state, four light-emitting diodes LD0 to LD3 are turned on. First, the control for turning on the light-emitting diodes LD0 to LD3 will be described. To turn on only the light-emitting diode LD0 (LD0: ON), only the input / output port IO0 is set to low (ground potential) as shown in the second row of column 353a, and IO1 to IO3 are set to a high impedance state. To light two light emitting diodes LD0 and LD1 (LD0, 1: ON), the input / output ports IO0 and IO1 are set to low and IO2 and IO3 are set to high impedance as shown in the third row of column 353a. To light three light emitting diodes LD0 to LD2 (LD0, 1, 2: ON), the input / output ports IO0 to IO2 are set to low and only IO3 is set to high impedance as shown in the fourth row of column 353a. To light all light emitting diodes LD0 to LD3 (LD0, 1, 2, 3: ON), all input / output ports IO0 to IO3 are set to low as shown in the fifth row of column 353a. By controlling in this way, the remaining battery voltage can be displayed by lighting the light emitting diodes LD0 to LD3. If the input / output port IO0 is set to high impedance as shown in column 353a, all light emitting diodes LD0 to LD3 can be turned off.

[0115] When detecting temperature using thermistors TH1 and TH2, as shown in column 353b, input / output port IO0 of input / output port group 353 is set to high, and the signal level of one of the corresponding thermistors TH1 and TH2 is set to high (VDD1 potential). For example, when detecting using thermistor TH1, if IO1 is turned on (high), switching element M1 is turned on, a predetermined voltage is applied across thermistor TH1, and microcomputer 351 can detect the voltage value of thermistor TH1 from input port AN1. When detecting using thermistor TH2, if IO2 is turned on (high), switching element M2 is turned on, and microcomputer 351 can detect the voltage value of thermistor TH2 from input port AN1. When detecting voltage by the upper voltage detection circuit 322A, if the input / output port IO0 is set to high and IO3 is set to on (high), the switching element M3 is turned on, and the microcomputer 351 can detect the voltage value of the upper voltage detection circuit 322A (upper cell unit 146) from the input port AN1. At this time, the input / output ports IO1 and IO2 must be set to low. In this way, the signal level of IO1 to IO3 is switched from low to high in sequence while the signal of IO0 remains high in any state. It should be noted that even if the input / output port IO0 is set to a high impedance state, which is a light-off state, instead of a high state, temperature detection by the thermistors TH1 and TH2 and voltage detection by the upper voltage detection circuit 322A can be performed alternatively. As described above, since multiple input signals are input to the input port AN1 while being switched using the signals of the input / output ports IO1 to IO3, only one input port AN1 is required, and the number of input ports can be reduced. EXAMPLES

[0116] FIG. 26 is a circuit diagram of a battery pack 100A according to a second embodiment of the present invention, showing a state in which the battery pack 100A is connected to a conventional power tool main body 1. The rated voltage of the battery pack 100A is 18V and cannot be switched, and the control unit including the microcomputer described in FIG. 19 to FIG. 21 is applied to the voltage fixed battery pack 100A, not to the voltage switchable battery pack 100. The power tool main body 1 shown on the left side of FIG. 26 is completely the same as the power tool main body 1 shown in FIG. 19. The battery pack 100A is a form obtained by removing the upper cell unit 146 and the associated protection circuit (protection IC 300), current consumption control means 310, lower positive terminal 172, and lower negative terminal 177 from the battery pack 100 shown in FIG. 19. Here, the same elements and circuits are given the same reference numerals. The cell unit 148 is substantially the same as the lower cell unit 147, but since there is no distinction between upper and lower, and the shape of the separator (not shown) that holds the battery cells is different, different numbers are used. In the conventional battery pack 15, the cell unit 148 was monitored only by the protection IC 320 without the control unit 350 shown in FIG. 26. However, in this embodiment, in addition to the protection IC 320, a control unit 350 having a microcomputer is added to the protection circuit of the battery cell. By adopting a protection circuit having a microcomputer in this way, it becomes possible for the battery pack 100A to determine whether or not a microcomputer is included in the power tool main body, and to change the control of the microcomputer on the battery pack 100A side depending on whether or not a microcomputer is included.

[0117] When the battery pack 100A is attached to the power tool main body 1 and the trigger switch 34 is pulled to allow current to flow, the control unit 350 wakes up from the start-up or sleep state and enters the normal mode. When starting up to the normal mode, the battery pack 100A measures the voltage at the LD terminal 168 by the LD terminal voltage detection circuit 328. This measurement allows the control unit 350 to detect whether the power tool main body 1 includes a microcomputer or not, and if a microcomputer is included, the control parameters are changed. In the example of FIG. 26, the control unit 350 determines that the power tool main body 1 does not include a microcomputer, so the control parameters remain set to the settings for a power tool without a microcomputer, i.e., the default values. The control parameters include the overcurrent threshold, the overdischarge voltage value, and the upper limit of the battery cell temperature, as shown in the first embodiment.

[0118] The current flowing through the cell unit 148 is measured by a microcomputer included in the control unit 350 by monitoring the voltage across the shunt resistor 329 using a current detection circuit 327. If the result of this measurement indicates that the control parameter for current monitoring exceeds the overcurrent threshold, the microcomputer in the control unit 350 turns the discharge inhibition signal 341 high to stop the rotation of the motor 35. In this way, by having the microcomputer in the control unit 350 monitor the current value instead of the protection IC 320, it has become possible to perform a variety of controls using the microcomputer.

[0119] Fig. 27 is a circuit diagram of a battery pack 100A according to a second embodiment of the present invention, showing the state in which it is connected to an 18V power tool main unit 1A with a microcomputer. In this figure, the power tool main unit 1A shown on the left is completely the same as that shown in Fig. 20. Also, the battery pack 100A shown on the right is completely the same as that shown in Fig. 26. The overload protection condition switching in the control unit 350 is mainly the current limit value during discharging. When the battery pack 100A is attached to a conventional power tool main unit 1 without a microcomputer, the control unit 350 switches the current limit value I maxHowever, if the power tool main body 1A includes a microcomputer, the current of the power tool main body is monitored by the main body-side microcomputer, so the current limit value I max Therefore, the control unit 350 does not need to set the current limit value I max Either no current limit is set, or the current limit is set to the current limit (e.g., 60A) that can be taken from the cell unit 148. This current limit is not determined by the constraints on the power tool main body 1A side, but depends on the performance of the battery cells. In this way, the battery pack 100A side does not need to limit the capacity of the battery pack more than necessary, so that the power tool main body 1A side can maximize the capacity of the battery pack that can take larger currents due to improved performance of the battery cells. Moreover, since the same current limit is applied to the conventional power tool main body 1, a highly compatible and reliable battery pack 100A can be realized. In the second embodiment, the switching of the overload protection conditions is not limited to the peak current value and average current value, but the cell temperature detection value, overdischarge voltage value, etc. may be changed. In addition, threshold values ​​are set for these values, and overload protection is not simply performed depending on whether or not they are exceeded. Instead, by utilizing the inclusion of a microcomputer in the control unit 350, calculations using these parameters may be performed to perform overload protection according to the calculation results. By using such an arithmetic formula, it is possible to control so that the overdischarge voltage changes when the cell temperature is high and when the cell temperature is low, for example, by increasing the overdischarge voltage threshold when the cell temperature is high and decreasing the overdischarge voltage threshold when the cell temperature is low. If it becomes necessary to stop the power tool as a result of monitoring by the control unit 350, the control unit 350 sends a discharge inhibition signal 341 to the switching element M41, thereby causing conduction between the source and drain of the switching element M41, so that the LD terminal 28 on the power tool main body 1A side goes to low level and the rotation of the motor 5 stops. EXAMPLES

[0120] FIG. 28 is a perspective view showing a battery pack 400 according to a third embodiment of the present invention. The battery pack 400 is provided with a plurality of connection terminals that engage with terminals of a charging device or a tool body to establish electrical continuity. The connection terminals provided here are composed of two connection terminal parts that are separated in the vertical direction, and the shape of the connection terminal parts is characteristic. The external shape of the battery pack 400 is almost the same as that of the battery pack 100 shown in the first embodiment, and the only difference in appearance is that the upper surface 415 of the upper case 410 does not have a partially raised step portion (see 115a, 115b in FIG. 12) and the lower surface 411 does not have a recessed portion (see 111a in FIG. 12) at the left front corner. A plurality of slots 420 are arranged in the step portion at the connection portion between the upper surface 415 and the lower surface 111, and the width and size of the slots 420 are almost the same as those of the battery pack 100 of the first embodiment. A raised portion 432 is formed on the rear side of the upper surface, and latches 441 are provided on both the left and right sides of the raised portion 432.

[0121] Ten battery cells 446 are housed inside the lower case 401. Here, an upper cell unit and a lower cell unit are provided, each of which has five cells connected in series, and a rated voltage of 18 V is output as the output of the parallel connection of these cell units. That is, the battery pack 400 is of a fixed voltage type. Each connection terminal is composed of an upper terminal part and a lower terminal part, which constitute one terminal. That is, the positive electrode terminal for charging is composed of an upper positive electrode terminal 461 and a lower positive electrode terminal 471, which are short-circuited. The positive electrode terminal for discharging is composed of an upper positive electrode terminal 462 and a lower positive electrode terminal 472, which are short-circuited. The upper positive electrode terminal 461 and the lower positive electrode terminal 471, and the upper positive electrode terminal 462 and the lower positive electrode terminal 472 are connected by a self-control protector (not shown).

[0122] The negative terminal is composed of upper negative terminal 467 and lower negative terminal 477, which are connected together. In this way, one connection terminal is divided into two connection terminal parts, so that the number and total area of ​​contact parts with the device side terminal on the power tool main body 1 side are increased, and problems such as heat generation due to poor contact that is likely to occur due to vibration during operation of the power tool are unlikely to occur, allowing stable use over a long period of time and achieving a long life for battery pack 400.

[0123] Of the connection terminals, the signal terminals for signal transmission, i.e., the T terminal set (upper T terminal 464 and lower T terminal 474), the V terminal set (upper V terminal 465 and lower V terminal 475), the LS terminal group (upper LS terminal 466 and lower LS terminal 476), and the LD terminal group (upper LD terminal 468 and lower LD terminal 478) are each composed of two terminals, and the upper and lower terminals are connected to each other to have the same potential. The upper connection terminals (461-462, 464-468) and the lower connection terminals (471-472, 474-478) are fixed to the circuit board 450. This circuit board 450 is equipped with an IC for protecting the battery cells, but is not provided with a microcomputer or a light emitting diode for indicating the remaining battery power.

[0124] Fig. 29 is a partially enlarged view of the connection terminal of Fig. 28. The upper terminal parts (465-468) and the lower terminal parts (476-478) are both substantially L-shaped in side view, and are fixed to the circuit board 450 with the legs of the upper and lower terminal parts aligned in the mounting direction. This fixing method is the same as that of the first embodiment shown in Figs. 4 and 5, and the legs are inserted through mounting holes in the circuit board 450 and soldered from the back side of the circuit board 450. Each of the upper terminal parts (465-468) and the lower terminal parts (476-478) has a fitting part 478c bent into a substantially V-shape so that the gap between the arms on both sides is narrowed. The fitting part in the conventional battery pack is arranged so that the peaks of the substantially V-shape are perpendicular to the insertion direction of the device side terminal. That is, in the conventional terminal parts, the ridgeline of the substantially V-shaped mountain portion (for example, the inner apex portion of the portion indicated by the fitting portion 478c) is configured to extend vertically. However, in this embodiment, the ridgeline is formed to extend obliquely instead of vertically, so that the length of the contact portion between the plate-shaped main body side terminal and the fitting portion of the terminal part can be increased.

[0125] FIG. 30(1) is a perspective view showing the upper terminal part 480. However, the legs of the upper terminal part 480 are omitted, and only the part located on the upper side of the circuit board 450 is shown. The upper terminal part 480 is formed by cutting out a flat plate made of conductive metal by pressing, bending it into a U-shape, and forming a predetermined bent shape in the arm part. Here, the surface that becomes the bottom of the U-shape, i.e., the bridge part 482, is bent so that it faces backward, and a right side surface 483 and a left side surface 484 are formed on the front side from both the left and right sides of the bridge part 482 extending in the vertical direction. The right side surface 483 and the left side surface 484 are formed to be symmetrical in the left-right plane, and the right side surface 483 and the left side surface 484 are parallel surfaces with a certain interval between them. Left and right arms 485 and 486 are formed forward from the front edges of the upper parts of the right side surface 483 and the left side surface 484, and the bases of the arms 485 and 486, i.e., the flat surfaces 485a and 486a, are parallel surfaces that are in the same position in the left-right direction as the right side surface 483 and the left side surface 484. On the front side of the flat surfaces 485a and 486a, bent portions 485b and 486b that are bent inward are formed. The bent portions 485b and 486b are flat, but the large bent portions facing outward are arranged so that the ridges of the mountains are oblique.

[0126] In front of the bent portions 485b and 486a, fitting portions 485c and 486c are formed by folding the fitting portions 485c and 486c in a generally V-shape. The fitting portions 485c and 486c are convex toward the inside. When the battery pack 100 is attached, the inner peaks of the fitting portions 485c and 486c come into contact with and slide on the plate-shaped device-side terminals. Therefore, even if the fitting portions 485c and 486c are generally V-shaped, their peaks (peaks) are configured with a large radius of curvature R1 or a smaller radius of curvature. This is because the sliding resistance between the device-side terminals and the fitting portions 485c and 486c is small when sliding, and the contact area between the fitting portions 485c and 486c and the device-side terminals is increased when not sliding and in contact, thereby reducing the electrical contact resistance. Guide portions 485d, 486d for guiding the plate-shaped device side terminal to be inserted between the fitting portions 485c, 486c are connected to the front sides of the fitting portions 485c, 486c. The guide portions 485d, 486d are substantially planar and have a shape that widens in the left-right direction toward the front side. Therefore, the tip portions 485e, 486e of the arm portions 485, 486 are shaped to be located below the arm portions 485, 486. The tip portions 485e, 486e are formed with rounded corners so as to have a small radius of curvature.

[0127] FIG. 30(2) is a diagram for explaining the positional relationship of the contact parts of the fitting parts 485c, 486c with the device side terminal. Here, only the left arm part 486 is shown, but the right arm part 485 has the same shape, except that it is plane symmetrical. The arm part 486 has a constant height width W in the front-rear direction, but the contact part of the fitting part 486c is located at the position shown by the thick line. The contact part shown by the thick line is a linear contact part or a rectangular contact area with a narrow width. The contact part shown by the thick line has a contact length W / cosθ times the length (=W) of the fitting part 486c when it is formed on a vertical line. In this way, the longitudinal direction of the contact part or contact area of ​​the fitting part 486c is arranged so as to be oblique to the mounting direction of the device side terminal on the contact surface with the device side terminal, so that the contact part or contact area can be made large, and the contact area with the device side terminal on the power tool main body can be made large. As a result, the contact resistance between the device side terminal and the fitting portion 486c can be reduced, and the heat generation of the terminal due to the increase in the contact resistance can be effectively suppressed. In addition, since the generation of an arc between the device side terminal can be suppressed, damage and melting of the arm portions 485 and 486 can be prevented. In addition, the upper positive electrode terminals 461 and 462 and the lower positive electrode terminals 471 and 472, which are power terminals, may be applied to a battery pack in which the positive electrode terminals of the upper cell unit 146 and the lower cell unit 147 are connected to each other in the same manner as in the first embodiment, and the low voltage side and the high voltage side can be switched in the same manner as in the first embodiment. In that case, the shape of the arm portion and the fitting portion of the third embodiment may be applied to the fitting portion of the upper terminal part 200 (see FIG. 5) and the lower terminal part 220 (see FIG. 5) described in the first embodiment.

[0128] The terminals for transmitting signals (upper terminal parts 464-466, 468 and lower terminal parts 474-476, 478 in FIG. 28) are also formed with two upper and lower mating parts, which are configured to have the same potential and pass the same signal. However, the upper and lower parts of the signal terminals may be similarly formed separately as device side terminals on the power tool main body side at different potentials, thereby increasing the number of signals transmitted. Also, since there is little need to use terminal parts that are completely separated into upper and lower parts for transmitting signals, the terminals may be formed as terminal parts that are linked up and down. Next, the shape of terminal part 500 linked up and down will be described with reference to FIG. 31.

[0129] FIG. 31 is a perspective view showing the shape of the terminal component 500. However, the legs of the terminal component 500 are not shown, and only the portion located on the upper side of the circuit board 450 is shown. In the terminal component 500, a notch groove 508 is formed in about the front half of the right arm 505 to divide the arm 505 into upper and lower parts, thereby forming an upper arm piece 506 and a lower arm piece 510. Similarly, a notch groove 512 is formed in about the front half of the left arm 506 to divide the arm 506 into upper and lower parts, thereby forming an upper arm piece 507 and a lower arm piece 511. Since the upper arm pieces 506, 507 and the lower arm pieces 510, 511 are divided by the notch grooves 508, 512 in this way, a configuration having two sets of arms can be realized in one terminal component 500, and a signal terminal that can maintain a good fitting state can be realized. The upper terminal set (506, 507) and the lower terminal set (510, 511) are respectively formed with mating portions (506c, 507c) and mating portions (510c, 511c) for mating with the plate-shaped main body side connection terminals (however, the mating portions 506c, 510c are not visible in FIG. 31). The upper mating portions (506c, 507c) are arranged such that the longitudinal direction of the contact portion or contact area is oblique. Similarly, the lower mating portions (510c, 511c) are arranged such that the longitudinal direction of the contact portion or contact area is oblique. The contact portions or contact areas of the upper and lower mating portions are arranged so that the longitudinal directions of the contact portions or contact areas are aligned in a line. The upper and lower mating portions may be arranged so that they are at the same position when viewed in the front-to-rear direction, and the longitudinal directions of the contact portions or contact areas of the upper and lower mating portions may not be aligned in a line. Also, the inclination of the longitudinal direction of the upper and lower mating parts may not be aligned, but may be in the opposite direction. For example, the shape of the upper arm set (506, 507) may be changed to a shape that is inverted from the lower terminal set (510, 511), that is, a shape that is symmetrical with respect to the horizontal plane. By forming the longitudinal direction of the contact area of ​​the mating part in an oblique direction rather than a vertical direction as described above, the length of the mating part can be made longer than in the conventional example in which the mating part is perpendicular to the mounting direction, and therefore the contact resistance can be reduced.

[0130] Although the shapes of the connection terminals (480, 500) used in the fixed voltage battery pack have been described above in the third embodiment, these terminal shapes may be configured to be applied to a voltage switchable battery pack such as in the first embodiment. For example, the arrangement of the fitting portion of the terminal part 500 shown in Fig. 31 may be adopted for the signal terminal part 240 shown in Fig. 9.

[0131] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the present invention. For example, the above embodiments are described using a battery pack with a voltage switch between 18 V and 36 V, but the voltage ratio that can be switched is not limited to this, and other voltage ratios that can be switched by a combination of series connection and parallel connection may be used.

[0132] Representative features of the invention according to the alternative embodiment of the present application are as follows: The battery pack according to the first aspect of the invention has the following features. A battery pack having at least first and second cell units as cell units in which a plurality of battery cells are connected in series, the battery pack being configured to be switchable between a series connection state in which the first cell unit is connected to a higher voltage side than the second cell unit and the first and second cell units are connected in series to each other, and a connection state other than the series connection state, The battery pack includes: a control unit directly or indirectly connected to the first and second cell units, the control unit being configured to monitor a state of a battery cell constituting the first cell unit and a state of a battery cell constituting the second cell unit, and to output a control signal for controlling discharge of the battery pack; a power supply circuit connected to the control unit and configured to supply a power supply voltage to the control unit; a case that houses the first cell unit, the second cell unit, the control unit, and the power supply circuit, the case being configured to connect the battery pack to a main body of an electrical device; A battery pack configured such that the power supply circuit is connected to one of the first and second cell units, the control unit is connected to the power supply circuit and the negative electrode of the one of the cell units, and the power supply circuit generates the power supply voltage from the voltage input from the one of the cell units and supplies it to the control unit. According to the first invention, it is possible to provide a battery pack that can be attached to an electric device body and that can switch the connection state of multiple cell units. It is also possible to provide a battery pack that includes a control unit that can control the discharge of the battery pack while monitoring the state of the multiple cell units. Furthermore, since the circuit for supplying the power supply voltage to the control unit is closed within one cell unit, it is possible to provide a battery pack that can stably control the discharge of the battery pack regardless of the connection state of the multiple cell units.

[0133] The battery pack according to the second aspect of the present invention has the following features. The battery pack includes: a first protection circuit connected to the first cell unit and configured to monitor a state of a battery cell constituting the first cell unit; a second protection circuit connected to the second cell unit and configured to monitor a state of a battery cell constituting the second cell unit; The control unit is connected to the first and second protection circuits, and is configured to monitor the state of the battery cells that constitute the first cell unit via the first protection circuit, and to monitor the state of the battery cells that constitute the second cell unit via the second protection circuit.

[0134] The battery pack according to the third aspect of the present invention has the following features. A battery pack configured such that the power supply circuit is connected to the second cell unit as one of the cell units, and the power supply voltage is supplied from the second cell unit to the control unit via the power supply circuit.

[0135] The battery pack according to the fourth aspect of the present invention has the following features. The battery pack has a signal terminal configured to be connected to the main body of the electrical device, and the control signal output from the control unit is output to the main body of the electrical device via the signal terminal.

[0136] The battery pack according to the fifth aspect of the present invention has the following features. A battery pack in which a current consumption control unit is connected to the other of the first and second cell units, and the current consumption control unit is configured to consume approximately the same amount of power as the power consumed by the control unit.

[0137] The battery pack according to the sixth aspect of the present invention has the following features. The battery pack is configured so that when the control unit is consuming power, the current consumption control unit also consumes power.

[0138] The battery pack according to the seventh aspect of the present invention has the following features. The battery pack has a detection unit connected to the control unit, and the detection unit is configured to detect physical quantities related to the battery pack or an electrical device main body connected to the battery pack, and output information about the physical quantities to the control unit.

[0139] The battery pack according to the eighth aspect of the present invention has the following features. The battery pack has, as the detection unit, a first voltage detection unit that connects the other of the first and second cell units to the control unit, and the first voltage detection unit is configured to output information about the voltage of the first cell unit as the physical quantity to the control unit.

[0140] The battery pack according to the ninth aspect of the present invention has the following features. The control unit is configured to control discharging or charging of the battery pack depending on whether the battery pack is in the series connection state or in a connection state other than the series connection state.

[0141] The battery pack according to the tenth aspect of the present invention has the following features. The battery pack has, as the detection unit, a current detection unit for detecting a current flowing through at least one of the multiple battery cells that constitute the first and second cell units, and the current detection unit is configured to output information of the current flowing through the battery cell as the physical quantity to the control unit.

[0142] The battery pack according to the eleventh aspect of the present invention has the following features. The battery pack has, as the detection unit, a temperature detection unit for detecting the temperature of at least one of the multiple battery cells that constitute the first and second cell units, and the temperature detection unit is configured to output information on the temperature of the battery cell to the control unit as the physical quantity.

[0143] The battery pack according to the twelfth aspect of the present invention has the following features. The battery pack has, as the detection unit, a second voltage detection unit configured to be connected to a terminal of the electrical device main body, and the second voltage detection unit is configured to output information on a voltage input from the terminal of the electrical device main body as the physical quantity to the control unit.

[0144] The battery pack according to the thirteenth aspect of the present invention has the following features. The control unit is configured to change a condition for overload protection depending on a type of the electric device body.

[0145] The electrical device according to the fourteenth aspect of the present invention has the following features. an electric device having the battery pack and at least a first electric device body as an electric device body connectable to the battery pack, When the battery pack is connected to the first electric device body, the battery pack is in the series connection state in which the first and second cell units are connected in series to each other, the second electric device body has a parallel connection circuit that connects the first and second cell units in parallel with each other, and when the battery pack is connected to the second electric device body, the battery pack is in the parallel connection state; When the battery pack is not connected to the first electrical device body, the battery pack is an electrical device in which the first and second cell units are in an unconnected state and electrically independent from each other.

[0146] The battery pack according to the fifteenth aspect of the present invention has the following features. The battery pack has a plurality of cell units in which a plurality of battery cells are connected in series, and is capable of switching between the output of the series connection of the cell units and the output of the parallel connection of the cell units, and a protection circuit is provided for each cell unit to monitor the state of the battery cells, and a microcomputer is provided to monitor the entire battery pack by inputting signals from the plurality of protection circuits to a protection circuit provided in the lowest cell unit that is connected to the ground side when connected in series among the plurality of cell units. Also, a power supply circuit is provided to generate power for driving the microcomputer, and the power supply circuit generates power from the output of the lowest cell unit that is closer to the ground side when connected in series. There are two cell units, an upper cell unit (first cell unit) that is located closer to the positive terminal when connected in series, and a lower cell unit (second cell unit) that is located closer to the negative terminal, and when the battery pack is attached to the main body of an electric device, the connection form of the upper cell unit and the lower cell unit is set to either series connection or parallel connection.

[0147] According to another feature of the present invention, the battery pack has a signal terminal for sending a stop signal (discharge stop signal) to the main body of the electric device, and when the microcomputer detects an abnormal output from any of the multiple protection circuits, it outputs a stop signal to stop the operation of the motor of the main body of the electric device connected to it. The protection circuit connected to the upper cell unit is a battery protection IC that monitors the terminal voltage of each battery cell included in the upper cell unit, and the protection circuit connected to the lower cell unit is composed of a battery management IC that integrates the functions of the protection circuit IC and the microcomputer into one chip. Here, an adjustment circuit is provided to balance the total power consumption of the protection circuit including the microcomputer of the lower cell unit and the power consumption of the protection circuit of the upper cell unit, so that the power consumption by the protection circuits is uniform. The adjustment circuit has a pseudo load for consuming the power consumed by the microcomputer, and is provided in the circuit on the upper cell unit side where the microcomputer is not provided.

[0148] According to another feature of the present invention, the microcomputer has a sleep function for turning off the power supply by itself when not in operation, and the adjustment circuit includes a circuit for putting the protection circuit on the upper cell unit side into a sleep state when the microcomputer goes into sleep. Furthermore, the protection circuit has a voltage balance adjustment function for balancing the voltages across the multiple cells. The battery pack has two independent pairs of positive and negative terminals, an upper cell unit is connected to the positive and negative terminals of one pair, and a lower cell unit is connected to the positive and negative terminals of the other pair. When the battery pack is connected to the main body of a high-voltage electrical device, the upper cell unit and the lower cell unit are connected in series, and when the battery pack is connected to the main body of a low-voltage electrical device, the upper cell unit and the lower cell unit are connected in parallel. When the battery pack is not attached to another device, the power lines of the upper cell unit and the lower cell unit are separated.

[0149] According to another feature of the present invention, a battery pack that switches the output voltage by changing the connection between series and parallel of two cell units is provided with a first protection circuit that monitors the state of the battery cells in the first cell unit on the high voltage side when connected in series, and a second protection circuit that monitors the state of the battery cells in the second cell unit on the low voltage side when connected in series. The output states of the first and second protection circuits are monitored by a microcomputer, and a discharge inhibition signal or a charge inhibition signal is sent to the main body of the connected electric device. The power supply for the microcomputer is generated from the output of the second cell unit by the power supply circuit, so that the power supply can be stably generated from the cell unit on the side where the ground potential does not change whether the battery unit is connected in series or in parallel. Using such a battery pack, it is now possible to operate various electric devices and power tools.

[0150] According to yet another feature of the present invention, there is provided a battery pack having a first cell unit and a second cell unit in which a plurality of cells are connected in series, and in which the output of the series connection of the first cell unit and the second cell unit or the output of the parallel connection of the first cell unit and the second cell unit can be switched depending on the connected electric device body, and the battery pack further includes a microcomputer that monitors the first cell unit and the second cell unit, and the microcomputer determines whether the output of the series connection of the first cell unit and the second cell unit or the output of the parallel connection is being supplied to the connected electric device body, and changes the overload protection condition according to the determination result. The overload protection condition is a limit value of the current flowing through the first cell unit or the second cell unit, and when the microcomputer detects that the limit value has been exceeded, it outputs a stop signal to stop the operation of the electric device body.

[0151] According to yet another feature of the present invention, two independent positive and negative terminals are provided, a first cell unit is connected to the positive and negative terminals of one set, and a second cell unit is connected to the positive and negative terminals of the other set, and when the battery pack is connected to a high-voltage electrical device main body, the first cell unit and the second cell unit are connected in series, and when the battery pack is connected to a low-voltage electrical device main body, the first cell unit and the second cell unit are connected in parallel, a protection circuit is provided for monitoring the state of the battery cells in each cell unit, and a microcontroller is provided in the protection circuit provided in one of the multiple cell units to monitor the multiple protection circuits, and the microcontroller determines whether the output of the battery pack is an output from a series connection state or an output from a parallel connection state by comparing the ground potential of the positive electrode of the first cell unit, which is provided closer to the positive terminal when the first cell unit and the second cell unit are connected in series, with the ground potential of the positive electrode of the second cell unit. The current limit value, which is a condition for overload protection, is switched between when the battery pack is connected to a high-voltage electrical device body and when it is connected to a low-voltage electrical device body. The current limit value when the battery pack is connected to a high-voltage electrical device body should be greater than the current limit value when the battery pack is connected to a low-voltage electrical device body. Note that it is also possible to set only the current limit value when the battery pack is connected to a low-voltage electrical device body without setting the current limit value when the battery pack is connected to a high-voltage electrical device body.

[0152] According to yet another feature of the present invention, the battery pack has an LD terminal (abnormal signal terminal) for outputting a discharge stop signal output from a microcomputer, and a semiconductor switching element is provided between the LD terminal and ground, and the discharge stop signal of the microcomputer is input to the gate signal of the semiconductor switching element, so that the LD terminal is grounded when the discharge stop signal is issued from the microcomputer. When the battery pack is not attached to another device, the power lines of the first cell unit and the second cell unit are electrically isolated. In addition, the overload protection conditions include either or both of the allowable upper limit temperature and the upper limit voltage value during charging of the first cell unit and the second cell unit, and when the microcomputer detects that the upper limit value has been exceeded, a discharge stop signal is output to stop the operation of the main body of the electrical device.

[0153] According to yet another feature of the present invention, a protection circuit for monitoring the state of the battery cells is provided in each of the upper cell unit and the lower cell unit, and a microcontroller is provided in the protection circuit on the lower cell unit side, which is located on the ground side when connected in series.The microcontroller also inputs a signal from the protection circuit on the upper cell unit side, and by comparing the potential of the positive electrode of the upper cell unit with the potential of the positive electrode of the lower cell unit, it determines whether an output in a series connection state or a parallel connection state is being supplied to the main body of the electrical equipment, and changes the overload protection conditions depending on the determination result. [Explanation of symbols]

[0154] 1,1A...power tool body, 2...housing, 3...handle portion, 4...trigger switch (operation switch), 5...motor, 10...battery pack mounting portion, 11a...rail groove, 12...curved portion, 14...projection portion, 15...battery pack, 20...terminal portion, 20a...vertical surface, 20b...horizontal surface, 21...base, 22...positive input terminal, 22a...terminal portion, 27...negative input terminal, 28...LD terminal, 30...power tool body, 30A...power tool body, 30B...power tool body, 32...housing, 33...handle portion, 34...operation switch, 35...motor, 40...battery pack mounting portion, 45...motor data input, 50... terminal section, 51... base, 52... positive input terminal, 52a... terminal section, 52b... connecting section, 52c... wiring section, 53... input / output port group, 53a... gap, 53b... gap, 54... connection terminal, 54a... terminal section, 54b... connecting section, 54c... wiring section, 57... negative input terminal, 57a... terminal section, 57b... connecting section, 57c... wiring section, 58... LD terminal, 59... short bar, 59a... connecting section, 59b, 59c... terminal section, 60... control section, 61... power supply circuit, 62... battery voltage detection circuit, 63... switch state detection circuit, 64... current detection circuit, 65... input line, 72A, 72B... Positive terminal, 72d...notch, 79...shorting bar, 79b...terminal portion, 79d...notch, 82...positive input terminal, 82a...terminal portion, 82b...connection portion, 82c...terminal portion for wiring, 87...negative input terminal, 87a...terminal portion, 87c...terminal portion for wiring, 89...shorting bar, 89a...connection portion, 89b, 89c...terminal portion, 100, 100A...battery pack, 101...lower case, 101a...front wall, 101b...rear wall, 101c...right side wall, 101d...left side wall, 103a, 103b...screw holes, 104...slit (air window), 110...upper case, 111...lower surface, 113...opening Mouth portion, 114...step portion, 115...upper surface, 115a...convex portion, 120...slot group arrangement area, 121 to 128...slot, 131...stopper portion, 132...raised portion, 134...slit (air window), 138a, 138b...rail, 141...latch, 142a...locking portion, 142b...locking portion, 145...separator, 146...upper cell unit, 147...lower cell unit, 147a...battery cell, 148...cell unit, 149...upper cell unit, 150...circuit board, 150a...surface side, 150b...back side, 151...mounting hole, 153a, 153b...land, 155,155a…Next resin, 156a…(Main area for pouring resin), 156b…(Sub - area for pouring resin), 157 - 159…Wiring patterns, 161, 162…Upper positive terminal, 162a, 162b…Arm parts, 164…T terminal, 165…V terminal, 166…LS terminal, 167…Upper negative terminal, 167a, 167b…Arm parts, 168…LD terminal, 171…Lower positive terminal, 172…Lower positive terminal, 172a…Arm part, 177…Lower negative terminal, 177a, 177b…Arm parts, 180…Substrate cover, 181…Connecting part, 181a…Upper surface, 181b…Front wall surface, 181c…Notch part, 182…Partition wall, 182a…Vertical wall part, 182b…Horizontal wall part, 182c…Left - end position, 183…Partition wall, 183a…Vertical wall part, 183b, 183c…Horizontal wall parts, 184…Partition wall, 184a, 184d…Vertical wall parts, 184b…Horizontal wall part, 184c…Blocking plate, 185…Partition wall, 187…Partition wall, 187a…Vertical wall part, 187b…Horizontal wall part, 188…Partition wall, 188a…Vertical wall part, 188b…Horizontal wall part, 190…Switch, 191…Prism, 200, 200A…Upper terminal parts, 201…Base part, 202…Bridge part, 203…Right - hand side surface, 204…Left - hand side surface, 203a, 204a…Bending parts, 203b, 204b…Protrusions, 203c, 204c…Cut - out parts, 205, 206…Arm parts, 205a, 206a…Flat parts, 205b, 206b…Bending parts, 205c, 206c…Flat parts, 205d, 206d…Fitting parts, 205e, 206e…Guiding parts, 205f, 206f…Notch parts, 207, 208…Leg parts, 207a, 208a…Cut - out parts, 209…Gap, 211…Gap, 220, 220A…Lower terminal parts, 221…Base part, 222…Bridge part, 223…Right - hand side surface, 223a…Bending part, 223c…Cut - out part, 224…Left - hand side surface, 225, 225A, 226…Arm parts, 225a, 226a…Flat parts, 225b, 226b…Bending parts, 225c, 226c…Flat parts, 225d, 226d…Fitting parts, 225e, 226e…Guiding parts, 225f, 226f…Notch parts, 227, 228…Leg parts, 227a, 228a…Cut - out parts, 231…Notch part, 240…Signal terminal parts, 241…Base part, 242…Bridge part, 243…Right - hand side surface, 243a…Extension part, 243b…Bending part, 243c…Cut - out part, 244…Left - hand side surface, 245, 246…Base parts of arm, 249, 250…Leg parts, 249a…Cut - out part, 250a,250b...step portion, 251-254...arm portion, 256...solder, 260...upper terminal part, 262...bridge portion, 263...right side surface, 263a...bent portion, 264...left side surface, 264b...dotted line, 264c...reinforcing surface, 265, 266...arm portion, 265d...fitting portion, 267, 268...leg portion, 280, 280A...lower terminal part, 282...bridge portion, 283...right side surface, 284...left side surface, 284b...dotted line, 284c...cut-out portion, 285, 286...arm portion, 285d...fitting portion, 291...notch portion, 300...protection IC, 301... start terminal, 302... operation signal, 305... over-discharge signal, 306... over-charge signal, 310... current consumption control means, 320... protection IC, 321... power supply circuit, 322, 322A... upper voltage detection circuit, 325... over-discharge signal, 326... over-charge signal, 327... current detection circuit, 328... LD terminal voltage detection circuit, 329... shunt resistor, 331... cell temperature detection means, 335... remaining capacity display means, 341... discharge inhibition signal, 342... connection line, 350... control unit, 351... microcomputer, 352... input port group, 353 ...input / output port group, 364...switching means, 400...battery pack, 401...lower case, 411...lower surface, 415...upper surface, 420...slot, 432...raised portion, 441...latch, 446...battery cell, 450...circuit board, 461, 462...upper positive terminal, 464...T terminal, 465...V terminal, 466...LS terminal, 467...upper negative terminal, 468...LD terminal, 471, 472...lower positive terminal, 474...T terminal, 475...V terminal, 476...LS terminal, 477...lower negative terminal, 478...LD terminal, 480...upper Terminal part, 482... bridge part, 483... right side surface, 484... left side surface, 485... arm part, 485a... flat part, 485b... bent part, 485c... mating part, 485d... guide part, 485e... tip part, 486... arm part, 486c... mating part, 500... terminal part, 505... arm part, 506, 507... arm piece, 508... notch groove, 509... arm part, 510, 511... arm piece, 512... notch groove, AN1... input port, IO0 to IO3... input / output port, LD0 to LD3... light-emitting diode, TH1 to TH3... thermistor, I, max …Current limit value (when discharging), T max …Upper limit, VCC1…Power supply voltage, VDD1…Power supply voltage (of the microcontroller), VDD2…Reference voltage (of the protection IC), V max …Cell voltage upper limit, Vmin …Cell voltage lower limit

Claims

1. a first cell unit and a second cell unit in which a plurality of battery cells are connected in series; a pair of first terminals electrically connected to the first cell unit and directly fitted to first device terminals of an electric device body; a pair of second terminals electrically connected to the second cell unit and directly fitted to second device terminals of the electric device body; a remaining capacity display unit configured to display a remaining battery capacity of the battery pack; a switch configured to be operated by an operator; The first and second cell units are configured to be switchable between a non-connected state in which the pair of first terminals and the pair of second terminals are not engaged with the first and second device terminals and the first and second cell units are not electrically connected to each other, and a series-connected state in which the pair of first terminals and the pair of second terminals are directly engaged with the first and second device terminals and the first and second cell units are connected in series to each other; the remaining capacity display unit is supplied with power from one of the first cell unit and the second cell unit regardless of whether the first cell unit and the second cell unit are in the non-connected state or the series-connected state; A battery pack characterized by:

2. A battery pack as claimed in claim 1, the remaining capacity display unit is configured to display the remaining battery capacity based on the voltage of the one of the cell units receiving the power supply when the switch is operated in either the unconnected state or the series-connected state of the first cell unit and the second cell unit; A battery pack characterized by:

3. A battery pack as claimed in claim 1, the one cell unit that supplies power to the remaining capacity display unit is located on the ground side in the series connection state; A battery pack characterized by:

4. A battery pack as claimed in claim 3, a microcomputer connected to the one of the cell units that supplies power to the remaining capacity display unit; A battery pack characterized by:

5. A battery pack as claimed in claim 4, The microcomputer has a normal mode in which it is constantly active and a sleep mode in which it is activated intermittently. A battery pack characterized by:

6. A battery pack as claimed in claim 4, the microcomputer outputs a discharge stop signal when an abnormality occurs in any of the plurality of battery cells. A battery pack characterized by:

7. A battery pack as claimed in claim 2, a microcomputer connected to one of the first and second cell units; When the switch is operated in either the case where the first and second cell units are in the non-connected state or the series-connected state, the microcomputer is configured to execute lighting control to display the remaining battery capacity using the remaining capacity display unit based on the voltage of one of the first cell unit and the second cell unit. A battery pack characterized by:

8. A battery pack as claimed in claim 7, The remaining capacity display unit has a plurality of light-emitting diodes, each of the plurality of light emitting diodes is connected to an input / output port of the microcomputer; A battery pack characterized by:

9. The battery pack of claim 8, A resistor is connected in series to each of the plurality of light emitting diodes. A battery pack characterized by:

10. A battery pack as claimed in claim 7, A signal indicating that the switch has been operated is input to the microcomputer. A battery pack characterized by:

11. The battery pack of claim 8, a temperature detection means for detecting a temperature of the battery pack; the temperature detection means is connected to the input / output port; A battery pack characterized by:

12. The battery pack of claim 1, and an adjustment unit that is connected to a cell unit other than the one cell unit that supplies power to the remaining capacity display unit and consumes power from the other cell unit. A battery pack characterized by:

13. The battery pack of claim 12, a microcomputer connected to the one of the cell units for supplying power to the remaining capacity display unit, The adjustment unit is controlled by the microcomputer. A battery pack characterized by:

14. A battery pack according to any one of claims 1 to 13; a first electrical device body to which the battery pack can be connected, the first electric device body includes a first device terminal that is directly fitted to the pair of first terminals and a second device terminal that is directly fitted to the pair of second terminals, when the battery pack is connected to the first electric device body, the pair of first terminals and the pair of second terminals are directly fitted to the first device terminals and the second device terminals, respectively, so that the first and second cell units are in the series connection state; When the battery pack is not connected to the first electric device body, the pair of first terminals and the pair of second terminals are not engaged with the first device terminals and the second device terminals, and the first and second cell units are in the unconnected state.

1. An electrical device comprising:

15. The battery pack according to any one of claims 1 to 13; a second electrical device body to which the battery pack can be connected, the second electric device body includes a first device terminal that is directly fitted to the pair of first terminals and a second device terminal that is directly fitted to the pair of second terminals, when the battery pack is connected to the second electric device body, the pair of first terminals and the pair of second terminals are directly fitted to the first device terminals and the second device terminals, respectively, so that the first and second cell units are in a parallel connection state in which the first and second cell units are connected in parallel to each other; When the battery pack is not connected to the second electric device body, the pair of first terminals and the pair of second terminals are not engaged with the first device terminals and the second device terminals, and the first and second cell units are in the unconnected state.

1. An electrical device comprising:

16. An electrical device as claimed in claim 15, The first device terminal and the second device terminal are the same terminal.

1. An electrical device comprising:

17. An electrical device comprising an electrical device body to which the battery pack according to any one of claims 1 to 13 can be connected, The electrical device body includes: a battery pack mounting portion in which the battery pack is mounted; a first device terminal provided in the battery pack mounting portion and directly fitted with the pair of first terminals; a second device terminal provided in the battery pack mounting portion and directly fitted with the pair of second terminals; 1. An electrical device comprising:

18. The electrical device according to claim 17, The first device terminal and the second device terminal are the same terminal.

1. An electrical device comprising:

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