Battery pack

Abstract

To provide art capable of suppressing the occurrence of short circuits and conduction failures at a battery side terminal of a battery pack.SOLUTION: A battery pack is detachable from electric apparatus or a charger including an apparatus side terminal. The battery pack includes: a battery cell; a circuit board electrically connected to the battery cell; and a battery side terminal which is electrically connected to the circuit board and contacts the apparatus side terminal to make an electrical connection to the apparatus side terminal. The battery side terminal includes: a positive electrode power terminal and a negative electrode power terminal for discharging from the battery cell or for charging to the battery cell; and at least one signal terminal electrically connected to the circuit board for signal communication to and from the circuit board. The surface of the positive electrode power terminal is plated with a first metal. The surface of one of the at least one signal terminal is plated with a second metal. The first metal is a pure metal other than Ag or an alloy not containing Ag. The second metal is a pure metal belonging to precious metals or an alloy of precious metals.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a battery pack. [Background technology]

[0002] Patent Document 1 discloses a battery pack that can be attached to or detached from an electrical device or charger that has an equipment-side terminal. The battery pack includes a battery cell, a circuit board electrically connected to the battery cell, and a battery-side terminal that is electrically connected to the circuit board and electrically connects to the equipment-side terminal by abutting against the equipment-side terminal. The battery-side terminal includes a positive power terminal and a negative power terminal for discharging from or charging the battery cell, and at least one signal terminal that is electrically connected to the circuit board and for signal communication between the battery cell and the circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2017-518193 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack described above, it is necessary to prevent the occurrence of short circuits and poor electrical continuity at the battery side terminals. This specification provides a technique capable of preventing the occurrence of short circuits and poor electrical continuity at the battery side terminals of the battery pack. [Means for solving the problem]

[0005] The battery pack disclosed in the present specification may be detachably attached to an electric device or a charger having an equipment-side terminal. The battery pack may include a battery cell, a circuit board electrically connected to the battery cell, and a battery-side terminal electrically connected to the circuit board and electrically connected to the equipment-side terminal by abutting against the equipment-side terminal. The battery-side terminal may include a positive power terminal and a negative power terminal for discharging from the battery cell or charging the battery cell, and at least one signal terminal electrically connected to the circuit board and for signal communication between the circuit board. The positive power terminal may be plated with a first metal on its surface. One of the at least one signal terminal may be plated with a second metal on its surface. The first metal may be a pure metal other than Ag or an alloy not including Ag. The second metal may be a pure metal belonging to a precious metal or an alloy of a precious metal.

[0006] When a battery pack is used in a moisture-rich environment, the metal on the surface of the positive power terminal is ionized, moves on the circuit board toward the negative power terminal, and is precipitated as a metal on the surface of the negative power terminal. This phenomenon is called ion migration. If the metal precipitated on the negative power terminal grows on the circuit board, it may cause a short circuit on the circuit board. Ion migration is most likely to occur in Ag, followed by Pb and Cu. Ion migration is more likely to occur when a large voltage is applied and less likely to occur when a small voltage is applied, so it is more likely to occur in the positive and negative power terminals and less likely to occur in the signal terminals. For this reason, as described above, by plating the surface of the positive power terminal with a pure metal other than Ag or an alloy that does not contain Ag, it is possible to suppress the ionization of Ag on the surface of the positive power terminal, and to suppress the occurrence of a short circuit due to ion migration. The above-mentioned pure metal other than Ag or alloy not containing Ag may be a pure metal other than Ag and Pb or an alloy not containing Ag and Pb, or may be a pure metal other than Ag, Pb and Cu or an alloy not containing Ag, Pb and Cu.

[0007] When the battery pack is attached to an electrical device or a charger, the battery terminal is maintained in contact with the device terminal of the electrical device or the charger. In this state, when minute vibrations are repeatedly applied to the battery terminal, wear progresses partially on the surface of the battery terminal, and the metal wear powder on the surface of the battery terminal oxidizes and accumulates on the surface of the battery terminal. This phenomenon is called fretting corrosion. When the oxidized wear powder accumulates on the surface of the battery terminal, there is a risk of poor conduction of the battery terminal. In general, since noble metals are not easily oxidized, poor conduction due to fretting corrosion is unlikely to occur. Conversely, since base metals are easily oxidized, poor conduction due to fretting corrosion is likely to occur. In addition, poor conduction due to fretting corrosion is unlikely to occur when a large voltage is applied, but is likely to occur when a small voltage is applied, so it is unlikely to occur in positive and negative power terminals, but is likely to occur in signal terminals. Therefore, by plating the surface of one of the at least one signal terminal with a pure metal belonging to the precious metal category or an alloy of precious metals as described above, it is possible to suppress the occurrence of poor electrical continuity due to fretting corrosion. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of a battery pack 2 according to the embodiment, as viewed from the front, lower right. [Diagram 2] FIG. 2 is a perspective view of a battery pack 2 according to the embodiment, seen from the upper rear left side. [Diagram 3] 2 is a perspective cross-sectional view of the vicinity of an air intake opening 40 and an exhaust opening 42 of a battery pack 2 according to the embodiment, as viewed from above on the front left. [Figure 4] 2 is a perspective view of a battery cell unit 14 of a battery pack 2 according to the embodiment, as viewed from the front, lower right. [Diagram 5] 2 is a perspective view of a battery cell 48 and a cell holder 50 of a battery pack 2 according to the embodiment, as viewed from the front, lower right. [Figure 6] 2 is a perspective view of a battery cell 48 and a cell holder 50 of a battery pack 2 according to the embodiment, as viewed from the upper rear left side. FIG. [Figure 7] FIG. 2 is a diagram showing a schematic diagram of an electrical system of a battery pack 2 according to an embodiment. [Figure 8] 1 is a cross-sectional view of a battery pack 2 according to an embodiment of the present invention. [Figure 9] FIG. 2 is a vertical cross-sectional view of a battery pack 2 according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Representative and non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide further improved battery packs.

[0010] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0011] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0012] In one or more embodiments, the battery pack may be detachably attached to an electric device or a charger having an equipment-side terminal. The battery pack may include a battery cell, a circuit board electrically connected to the battery cell, and a battery-side terminal electrically connected to the circuit board and electrically connected to the equipment-side terminal by abutting against the equipment-side terminal. The battery-side terminal may include a positive power terminal and a negative power terminal for discharging from the battery cell or charging the battery cell, and at least one signal terminal electrically connected to the circuit board and for signal communication between the circuit board. The positive power terminal may be plated with a first metal on its surface. One of the at least one signal terminal may be plated with a second metal on its surface. The first metal may be a pure metal other than Ag or an alloy not including Ag. The second metal may be a pure metal belonging to a precious metal or an alloy of a precious metal.

[0013] According to the above configuration, it is possible to prevent short circuits caused by ion migration and poor electrical continuity caused by fretting corrosion at the battery side terminals of the battery pack.

[0014] In one or more embodiments, the negative power supply terminal may be plated with a third metal on its surface. The third metal may be a pure metal other than Ag or an alloy that does not contain Ag.

[0015] According to the above configuration, it is possible to suppress the occurrence of a short circuit due to ion migration at the battery side terminal of the battery pack.

[0016] In one or more embodiments, the third metal may be the same metal as the first metal.

[0017] According to the above configuration, the plating process can be common to the positive power supply terminal and the negative power supply terminal, so that the battery pack can be manufactured more easily.

[0018] In one or more embodiments, all of the at least one signal terminal may have a surface plated with the second metal.

[0019] According to the above configuration, the plating process can be performed on all of the at least one signal terminal in a common manner, which makes it easier to manufacture the battery pack.

[0020] In one or more embodiments, the first metal may be Sn.

[0021] According to the above configuration, it is possible to improve the slidability when the battery-side terminal that is plated with the first metal slides against the device-side terminal.

[0022] In one or more embodiments, the second metal may be Ag.

[0023] According to the above configuration, it is possible to reduce the electrical resistance of the part of the battery side terminal that is plated with the second metal.

[0024] (Example) The battery pack 2 shown in Figs. 1 and 2 is detachably attached to an electric device (not shown). The electric device can operate by using power discharged from the battery pack 2. The electric device may be, for example, an electric tool powered by a motor, such as a screwdriver or drill, or an electric working machine powered by a motor, such as a grass cutter or blower. Alternatively, the electric device may be an electric device that does not have a motor, such as a light, radio, or speaker. The battery pack 2 is detachably attached to a charger (not shown). The charger can charge the battery pack 2.

[0025] The battery pack 2 includes a main body 4, a right support portion 6, a left support portion 8, and a grip portion 10. The main body 4 has a substantially rectangular parallelepiped shape. The main body 4 includes a front surface 4a, a rear surface 4b, a right surface 4c, a left surface 4d, an upper surface 4e, and a lower surface 4f. The vertical dimension of the main body 4 is larger than the front-rear dimension of the main body 4. The left-right dimension of the main body 4 is larger than the vertical dimension of the main body 4. The vertical dimension of the main body 4 is, for example, within a range of 150.0 mm to 250.0 mm, more specifically, 171.5 mm. The front-rear dimension of the main body 4 is, for example, within a range of 70.0 mm to 120.0 mm, more specifically, 90.0 mm. The left-right dimension of the main body 4 is, for example, within a range of 170.0 mm to 210.0 mm, more specifically, 190.0 mm. The above dimensions of the main body 4 are merely examples, and the dimensions of the main body 4 may be smaller or larger. The right support portion 6 protrudes upward from the vicinity of the right end of the upper surface 4e of the main body 4. The left support portion 8 protrudes upward from the vicinity of the left end of the upper surface 4e of the main body 4. The grip portion 10 extends in the left-right direction and connects the vicinity of the upper end of the left surface of the right support portion 6 to the vicinity of the upper end of the right surface of the left support portion 8. A user can carry the battery pack 2 by gripping the grip portion 10. The battery pack 2 does not have to include the right support portion 6, the left support portion 8, and the grip portion 10. The weight of the battery pack 2 is, for example, within a range of 1.0 kg to 4.0 kg, and more specifically, 2.2 kg. The rated voltage of the battery pack 2 is, for example, within a range of 36 V to 108 V, and more specifically, 57.6 V. The rated capacity of the battery pack 2 is, for example, within a range of 3.0 Ah to 12.0 Ah, and more specifically, 4.0 Ah. Note that the weight, rated voltage, and rated capacity of the battery pack 2 described above are merely examples, and the weight, rated voltage, and rated capacity of the battery pack 2 may be smaller or larger.

[0026] The battery pack 2 comprises a casing 12 and a battery cell unit 14 (see FIG. 3) housed inside the casing 12. The casing 12 comprises a front casing 12a and a rear casing 12b. The front casing 12a defines the outer shapes of the main body 4, right support part 6, left support part 8, and the front half of the grip part 10. The rear casing 12b defines the outer shapes of the main body 4, right support part 6, left support part 8, and the rear half of the grip part 10.

[0027] As shown in FIG. 2, a remaining battery indicator 16 and a remaining battery button 18 are provided near the front end of the upper surface 4e of the main body 4. The remaining battery indicator 16 displays the remaining battery level of the battery pack 2. The remaining battery button 18 is a button for a user to turn on the display of the remaining battery level by the remaining battery indicator 16. The remaining battery indicator 16 is turned on when the remaining battery button 18 is turned on, and is automatically turned off after a predetermined time has passed. In the front-rear direction, the remaining battery indicator 16 and the remaining battery button 18 are disposed forward of the grip portion 10. In the left-right direction, the remaining battery indicator 16 and the remaining battery button 18 are disposed leftward of the right support portion 6 and rightward of the left support portion 8. As shown in FIG. 3, a display circuit board 17 is accommodated inside the casing 12 and below the remaining battery indicator 16 and the remaining battery button 18. The display circuit board 17 is held by the front casing 12a. The display circuit board 17 includes a display switch 17a (see FIG. 7) that detects a user's operation on the remaining amount display button 18, and a plurality of LEDs 17b (see FIG. 7) that turn on / off the remaining amount display indicator 16.

[0028] As shown in FIG. 1, a terminal interface (hereinafter also referred to as IF) section 20 is formed in the front lower part near the center in the left-right direction of the main body section 4. The terminal IF section 20 has a plurality of terminal accommodating sections 22 arranged side by side in the left-right direction. A terminal opening 24 is formed in the lower surface of each terminal accommodating section 22. The terminal opening 24 is a slit-shaped through hole having a longitudinal direction in the front-rear direction. Each terminal accommodating section 22 accommodates a battery side terminal 54 (see FIG. 4). When the battery pack 2 is attached to an electric device or a charger, the device side terminal (not shown) of the electric device or the charger passes through the terminal opening 24 and enters the terminal accommodating section 22. As a result, the device side terminal of the electric device or the charger comes into mechanical contact with the battery side terminal 54 and is electrically connected.

[0029] A first guide groove 26 and a second guide groove 28 are formed on the right surface 4c of the main body 4, extending upward from the lower end of the right surface 4c. As shown in FIG. 2, a first guide groove 30 and a second guide groove 32 are formed on the left surface 4d of the main body 4, extending upward from the lower end of the left surface 4d. When the battery pack 2 is attached to an electric device or a charger, guide ribs (not shown) provided on the electric device or the charger fit into the first guide grooves 26, 30 and the second guide grooves 28, 32, thereby positioning the battery pack 2 relative to the electric device or the charger and regulating the moving direction of the battery pack 2 relative to the electric device or the charger. As shown in FIG. 1, a hook engagement groove 34 is formed on the front surface 4a of the main body 4. When the battery pack 2 is attached to an electric device, a hook (not shown) provided on the electric device engages with the hook engagement groove 34, thereby fixing the battery pack 2 to the electric device.

[0030] A plurality of air supply openings 36 are formed on the right surface 4c of the main body 4. As shown in Fig. 2, a plurality of air supply openings 38 are formed on the left surface 4d of the main body 4. As shown in Fig. 1, a plurality of air supply openings 40 are formed on the front surface 4a of the main body 4. As shown in Fig. 2, a plurality of exhaust openings 42 are formed on the rear surface 4b of the main body 4.

[0031] As shown in FIG. 3, a rib 44 is provided on each of the multiple air intake openings 40 on the front surface 4a of the main body 4. The rib 44 includes a bottom plate portion 44a that protrudes rearward from the lower edge of the air intake opening 40 and then bends rearward and upward, and side plate portions 44b that protrude rearward from the left and right edges of the air intake opening 40 and connect to the left and right ends of the bottom plate portion 44a. By providing the rib 44 on the air intake opening 40, it is possible to prevent a user holding the grip portion 10 from viewing the inside of the main body 4 through the air intake opening 40. In addition, by providing the rib 44 on the air intake opening 40, it is possible to prevent water or foreign matter from entering the inside of the main body 4 from the outside through the air intake opening 40.

[0032] A rib 46 is provided in each of the multiple exhaust openings 42 on the rear surface 4b of the main body 4. The rib 46 includes a bottom plate portion 46a that protrudes forward from the lower edge of the exhaust opening 42 and then bends forward and upward, and side plate portions 46b that protrude forward from the left and right edges of the exhaust opening 42 and connect to the left and right ends of the bottom plate portion 46a. By providing the rib 46 on the exhaust opening 42, it is possible to prevent the inside of the main body 4 from being viewed through the exhaust opening 42 by a user holding the grip portion 10. In addition, by providing the rib 46 on the exhaust opening 42, it is possible to prevent water or foreign matter from entering the inside of the main body 4 from the outside through the exhaust opening 42.

[0033] 4, the battery cell unit 14 includes a plurality of battery cells 48, a resin cell holder 50 that holds the plurality of battery cells 48, and a control circuit board 52 that is held by the cell holder 50 below the cell holder 50. A battery-side terminal 54 is provided on the underside of the control circuit board 52.

[0034] Each of the battery cells 48 is, for example, a lithium ion battery cell. Each of the battery cells 48 has a substantially cylindrical shape and is arranged so that the longitudinal direction is along the front-rear direction. The shape of each of the battery cells 48 is, for example, 18650 type, with a diameter of 18 mm and a longitudinal dimension of 65 mm. The battery cells 48 are arranged in four stages in the vertical direction. The battery cells 48 are arranged in eight rows in the horizontal direction. The battery cells 48 are arranged in a rectangular lattice shape, for example, a square lattice shape. The battery cells 48 arranged in the same stage in the vertical direction are positioned substantially equal to each other in the vertical direction and spaced apart in the horizontal direction. The battery cells 48 arranged in the same row in the horizontal direction are positioned substantially equal to each other in the horizontal direction and spaced apart in the vertical direction. As shown in FIG. 5 and FIG. 6, each of the battery cells 48 has a positive electrode 48a at one of the front end and the rear end, and a negative electrode 48b at the other of the front end and the rear end. Metal lead plates 56 (see FIG. 4) are attached to the positive electrodes 48a and negative electrodes 48b of each of the multiple battery cells 48. As shown in FIG. 4, some of the lead plates 56 are directly inserted into the control circuit board 52 and are thereby electrically connected to the control circuit board 52, and the remaining lead plates 56 are electrically connected to the control circuit board 52 via lead wires 58.

[0035] As shown in Figures 5 and 6, the cell holder 50 has a generally rectangular parallelepiped shape. The cell holder 50 has a front surface 50a, a rear surface 50b, a right surface 50c, a left surface 50d, a top surface 50e, and a bottom surface 50f. The cell holder 50 has a front cell holder 60 and a rear cell holder 62. The front cell holder 60 holds the front ends of the multiple battery cells 48. The rear cell holder 62 holds the rear ends of the multiple battery cells 48.

[0036] 5, multiple air supply openings 64 are formed on the right surface 50c of the cell holder 50. In this embodiment, two air supply openings 64 are formed on the right surface 50c of the cell holder 50, one air supply opening 64 is disposed facing the space between the first battery cell 48 from the top and the second battery cell 48 from the top inside the cell holder 50, and the other air supply opening 64 is disposed facing the space between the first battery cell 48 from the bottom and the second battery cell 48 from the bottom inside the cell holder 50.

[0037] 6, multiple air supply openings 66 are formed on the left surface 50d of the cell holder 50. In this embodiment, two air supply openings 66 are formed on the left surface 50d of the cell holder 50, with one air supply opening 66 being positioned facing the space inside the cell holder 50 between the first battery cell 48 from the top and the second battery cell 48 from the top, and the other air supply opening 66 being positioned inside the cell holder 50 facing the space inside the cell holder 50 between the first battery cell 48 from the bottom and the second battery cell 48 from the bottom.

[0038] A plurality of air supply openings 68 are formed in the top surface 50e of the cell holder 50. In this embodiment, two air supply openings 68 are formed in the top surface 50e of the cell holder 50, one air supply opening 68 is disposed facing the space between the third battery cell 48 from the right and the fourth battery cell 48 from the right inside the cell holder 50, and the other air supply opening 68 is disposed facing the space between the third battery cell 48 from the left and the fourth battery cell 48 from the left inside the cell holder 50.

[0039] 5, a plurality of air supply openings 70 are formed on the bottom surface 50f of the cell holder 50. In this embodiment, two air supply openings 70 are formed on the bottom surface 50f of the cell holder 50, one air supply opening 70 is disposed facing the space between the third battery cell 48 from the right and the fourth battery cell 48 from the right inside the cell holder 50, and the other air supply opening 70 is disposed facing the space between the third battery cell 48 from the left and the fourth battery cell 48 from the left inside the cell holder 50.

[0040] Each of the multiple air supply openings 64, 66, 68, 70 is formed across the front cell holder 60 and the rear cell holder 62. Each of the multiple air supply openings 64, 66, 68, 70 has an elongated hole shape with a longitudinal direction in the front-rear direction. The front end of each of the multiple air supply openings 64, 66, 68, 70 is disposed, for example, at a position rearward from the front ends of the multiple battery cells 48 by a quarter of the length of the multiple battery cells 48 in the front-rear direction. The rear end of each of the multiple air supply openings 64, 66, 68, 70 is disposed, for example, at a position forward from the rear ends of the multiple battery cells 48 by a quarter of the length of the multiple battery cells 48 in the front-rear direction.

[0041] As shown in FIG. 6, a plurality of electrode openings 72 and a plurality of exhaust openings 74 are formed on the rear surface 50b of the cell holder 50. The electrode openings 72 are arranged corresponding to the rear ends of the battery cells 48, and the positive electrodes 48a or negative electrodes 48b of the battery cells 48 are exposed. The lead plate 56 (see FIG. 4) is arranged behind the rear surface 50b of the cell holder 50, and abuts against the positive electrodes 48a or negative electrodes 48b of the battery cells 48 through the electrode openings 72. The exhaust openings 74 are arranged at positions surrounded by the four electrode openings 72. That is, the exhaust openings 74 are arranged facing the space surrounded by the four battery cells 48 inside the cell holder 50. Note that no exhaust opening 74 is formed corresponding to the rear surface 50b of the cell holder 50 between the battery cell 48 in the first row from the right and the battery cell 48 in the second row from the right. Moreover, no exhaust opening 74 corresponding to the rear surface 50b of the cell holder 50 is formed between the first battery cell 48 from the left and the second battery cell 48 from the left. Furthermore, between the second battery cell 48 from the top and the third battery cell 48 from the top (i.e., the second battery cell from the bottom), corresponding exhaust openings 74 are formed between the third battery cell 48 from the right and the fourth battery cell 48 from the right, and between the third battery cell 48 from the left and the fourth battery cell 48 from the left, but no exhaust openings 74 are formed in any other positions.

[0042] As shown in Fig. 5, a plurality of electrode openings 76 are formed on the front surface 50a of the cell holder 50. The plurality of electrode openings 76 are arranged corresponding to the front ends of the plurality of battery cells 48, and the positive electrodes 48a or negative electrodes 48b of the plurality of battery cells 48 are exposed. The lead plate 56 (see Fig. 4) is arranged in front of the front surface 50a of the cell holder 50, and abuts against the positive electrodes 48a or negative electrodes 48b of the battery cells 48 via the electrode openings 76. Unlike the rear surface 50b of the cell holder 50, no openings other than the electrode openings 76 are formed on the front surface 50a of the cell holder 50.

[0043] 4, the battery side terminal 54 includes a power terminal 78 and a signal terminal 80. The power terminal 78 includes a positive power terminal 78a and a negative power terminal 78b located to the right of the positive power terminal 78a. The signal terminal 80 is located between the positive power terminal 78a and the negative power terminal 78b. The signal terminal 80 includes a charge / discharge control terminal 80a arranged adjacent to the right of the positive power supply terminal 78a, a signal receiving terminal 80b arranged adjacent to the right of the positive power supply terminal 78a and to the rear of the charge / discharge control terminal 80a, an over-discharge output terminal 80c arranged adjacent to the right of the charge / discharge control terminal 80a, a signal transmitting terminal 80d arranged adjacent to the right of the signal receiving terminal 80b and to the rear of the over-discharge output terminal 80c, a connection detection terminal 80e arranged adjacent to the right of the over-discharge output terminal 80c, and an operation input terminal 80f arranged adjacent to the right of the signal transmitting terminal 80d and to the rear of the connection detection terminal 80e.

[0044] The positive power supply terminal 78a and the negative power supply terminal 78b are made of a Cu alloy as a base material, and are plated with Cu as an undercoat, followed by Sn plating. Instead of Sn plating, they may be plated with a pure metal such as Ni that belongs to the base metals, or with a pure metal other than Ag such as Au that belongs to the noble metals. Alternatively, they may be plated with an alloy that does not contain Ag.

[0045] When the battery pack 2 is used in a moisture-rich environment, the metal on the surface of the positive power terminal 78a is ionized, moves on the control circuit board 52 toward the negative power terminal 78b, and is again deposited as metal on the surface of the negative power terminal 78b. This phenomenon is called ion migration. If the metal deposited on the negative power terminal 78b grows on the control circuit board 52, a short circuit may occur on the control circuit board 52. Ion migration is most likely to occur with Ag. In addition, ion migration is likely to occur when a large voltage is applied and is unlikely to occur when a small voltage is applied, so that it is likely to occur on the power terminal 78 and unlikely to occur on the signal terminal 80. For this reason, by plating the positive power terminal 78a and the negative power terminal 78b with a pure metal other than Ag or an alloy not containing Ag, as described above, it is possible to suppress the occurrence of a short circuit due to ion migration. In particular, by plating the surface of the positive power terminal 78a with a pure metal other than Ag or an alloy not containing Ag, it is possible to suppress ionization of Ag on the surface of the positive power terminal 78a, and to suppress the occurrence of a short circuit due to ion migration. Note that the above-mentioned pure metal other than Ag or alloy not containing Ag may be a pure metal other than Ag and Pb or an alloy not containing Ag and Pb, or may be a pure metal other than Ag, Pb, and Cu or an alloy not containing Ag, Pb, and Cu.

[0046] The charge / discharge control terminal 80a, the signal receiving terminal 80b, the over-discharge output terminal 80c, the signal transmitting terminal 80d, the connection detection terminal 80e, and the operation input terminal 80f are made of a Cu alloy as a base material, with Cu plating applied as an undercoat and Ag plating applied on top of that. Note that instead of Ag plating, a pure metal such as Au or a precious metal alloy may be plated.

[0047] When the battery pack 2 is attached to an electric device or a charger, the battery terminal 54 is maintained in contact with the device terminal of the electric device or the charger. In this state, when minute vibrations are repeatedly applied to the battery terminal 54, wear progresses partially on the surface of the battery terminal 54, and the metal wear powder on the surface of the battery terminal 54 oxidizes and accumulates on the surface of the battery terminal 54. This phenomenon is called fretting corrosion. When the oxidized wear powder accumulates on the surface of the battery terminal 54, there is a risk of a conduction failure of the battery terminal 54. In general, since noble metals are not easily oxidized, conduction failure due to fretting corrosion is not likely to occur. Conversely, since base metals are easily oxidized, conduction failure due to fretting corrosion is likely to occur. In addition, conduction failure due to fretting corrosion is not likely to occur when a large voltage is applied, but is likely to occur when a small voltage is applied, so it is unlikely to occur in the power terminal 78 but is likely to occur in the signal terminal 80. Therefore, as described above, by plating the charge / discharge control terminal 80a, the signal receiving terminal 80b, the over-discharge output terminal 80c, the signal transmitting terminal 80d, the connection detection terminal 80e, and the operation input terminal 80f with a pure metal belonging to the precious metals or an alloy of precious metals, it is possible to prevent poor conductivity due to fretting corrosion.

[0048] A plurality of through holes 82 are formed in the control circuit board 52. In this embodiment, four through holes 82 are formed in the control circuit board 52. One through hole 82 extends in the front-rear direction between the positive power supply terminal 78a and the charge / discharge control terminal 80a, and between the positive power supply terminal 78a and the signal receiving terminal 80b. Another through hole 82 extends in the front-rear direction between the charge / discharge control terminal 80a and the over-discharge output terminal 80c, and between the signal receiving terminal 80b and the signal transmitting terminal 80d. Yet another through hole 82 extends in the front-rear direction between the over-discharge output terminal 80c and the connection detection terminal 80e, and between the signal transmitting terminal 80d and the operation input terminal 80f. Yet another through hole 82 extends in the front-rear direction between the connection detection terminal 80e and the negative power supply terminal 78b, and between the operation input terminal 80f and the negative power supply terminal 78b. By forming multiple through holes 82 in the control circuit board 52, even if a conductive substance such as water adheres to the surface of the control circuit board 52, it is possible to prevent short circuits from occurring between the power supply terminals 78, between the signal terminals 80, and between the power supply terminals 78 and the signal terminals 80.

[0049] As shown in FIG. 7, the battery cells 48 are electrically connected between the positive power supply terminal 78a and the negative power supply terminal 78b. The control circuit board 52 includes an MPU (Micro Processing Unit) 84, a power supply circuit 86, an AFE (Analog Front End) 88, a temperature detection unit 90, a current detection unit 92, a charge / discharge control unit 94, a signal communication unit 96, an over-discharge output unit 98, an operation input unit 100, and a connection detection unit 102. The MPU 84 controls the operation of the battery pack 2. The MPU 84 is electrically connected to the display switch 17a and the LED 17b of the display circuit board 17. The power supply circuit 86 steps down the DC power from the battery cells 48 to a voltage suitable for the operation of the MPU 84 and supplies it to the MPU 84. The current detection unit 92 detects the current flowing through the battery cells 48 and outputs it to the AFE 88. The AFE 88 amplifies the voltage of each of the battery cells 48 and the current detected by the current detection unit 92 so that the voltage can be recognized by the MPU 84, and outputs the amplified voltage to the MPU 84. The temperature detection unit 90 detects the temperature of the battery cells 48 using a thermistor (not shown) provided in the cell holder 50, and outputs the detected temperature to the MPU 84. The charge / discharge control unit 94 electrically connects the MPU 84 to the charge / discharge control terminal 80a. When the state of the battery pack 2 is normal, the charge / discharge control unit 94 outputs a charge / discharge permission signal to the charge / discharge control terminal 80a, and when the state of the battery pack 2 is abnormal, the charge / discharge prohibition signal to the charge / discharge control terminal 80a. The signal communication unit 96 electrically connects the MPU 84 to the signal receiving terminal 80b, and between the MPU 84 and the signal transmitting terminal 80d. The signal communication unit 96 inputs a signal received at the signal receiving terminal 80b to the MPU 84 by serial communication, and transmits a signal output from the MPU 84 at the signal transmitting terminal 80d by serial communication. The overdischarge output unit 98 electrically connects between the MPU 84 and the overdischarge output terminal 80c. When the multiple battery cells 48 become overdischarged, the overdischarge output unit 98 outputs a signal notifying that the multiple battery cells 48 have become overdischarged to the overdischarge output terminal 80c. The operation input unit 100 electrically connects between the MPU 84 and the operation input terminal 80f.The operation input unit 100 receives, via an operation input terminal 80f, an operation input signal transmitted from an electrical device to which the battery pack 2 is attached when an operation switch of the electrical device is turned on by a user, and inputs the signal to the MPU 84. The connection detection unit 102 electrically connects between the MPU 84 and the connection detection terminal 80e. When the battery pack 2 is electrically connected to an electrical device or a charger, the connection detection unit 102 inputs a connection detection signal to the MPU 84. Note that the configuration shown in FIG. 7 is merely an example, and in particular, the signal terminal 80 and / or the components connected to the signal terminal 80 may be of a type other than those described above, and may be in a number other than those described above.

[0050] When the battery pack 2 is attached to the charger, the battery cells 48 are cooled by a blower (not shown) provided in the charger in order to prevent the battery cells 48 from becoming excessively hot when charging the battery cells 48. In the battery pack 2 of this embodiment, the blower provided in the charger sucks air from inside the casing 12 to the outside through the exhaust opening 42 on the rear surface 4b of the main body 4 shown in Fig. 2. The flow of air inside the casing 12 when the battery packs 2 are cooled in this manner will be described below.

[0051] As shown in Fig. 8, when air is sucked out from inside the casing 12 to the outside through the exhaust opening 42 on the rear surface 4b of the main body 4, air flows from the outside into the casing 12 through the air supply opening 36 on the right surface 4c of the main body 4, the air supply opening 38 on the left surface 4d of the main body 4, and the air supply opening 40 on the front surface 4a of the main body 4. In addition, as shown in Fig. 9, air also flows from the outside to the inside of the casing 12 through the terminal opening 24 of the terminal IF section 20, although in a small amount.

[0052] Most of the air flowing in through the air supply opening 36 flows into the inside of the cell holder 50 through the multiple air supply openings 64 on the right surface 50c of the cell holder 50. The remainder of the air flowing in through the air supply opening 36 flows through the space between the casing 12 and the cell holder 50, and flows into the inside of the cell holder 50 through the multiple air supply openings 68 on the upper surface 50e of the cell holder 50 and the multiple air supply openings 70 on the lower surface 50f of the cell holder 50.

[0053] Most of the air flowing in through the air supply opening 38 flows into the cell holder 50 through the multiple air supply openings 66 on the left surface 50d of the cell holder 50. The remainder of the air flowing in through the air supply opening 38 flows through the space between the casing 12 and the cell holder 50, and flows into the cell holder 50 through the multiple air supply openings 68 on the upper surface 50e of the cell holder 50 and the multiple air supply openings 70 on the lower surface 50f of the cell holder 50.

[0054] As shown in Figure 8, air flowing in through the air supply opening 40 flows through the space between the casing 12 and the cell holder 50, and flows into the interior of the cell holder 50 through multiple air supply openings 64 on the right surface 50c of the cell holder 50, multiple air supply openings 66 on the left surface 50d of the cell holder 50, multiple air supply openings 68 on the top surface 50e of the cell holder 50, and multiple air supply openings 70 on the bottom surface 50f of the cell holder 50.

[0055] As shown in FIG. 9, the air flowing in from the terminal opening 24 passes through the through-holes 82 of the control circuit board 52 and flows into the inside of the cell holder 50 via the multiple air supply openings 70 in the lower surface 50f of the cell holder 50.

[0056] The air that flows into the cell holder 50 through the multiple air supply openings 64 flows from right to left through the spaces between vertically adjacent battery cells 48. The air that flows into the cell holder 50 through the multiple air supply openings 66 flows from left to right through the spaces between vertically adjacent battery cells 48. The air that flows into the cell holder 50 through the multiple air supply openings 68 flows from top to bottom through the spaces between horizontally adjacent battery cells 48. The air that flows into the cell holder 50 through the multiple air supply openings 70 flows from bottom to top through the spaces between horizontally adjacent battery cells 48.

[0057] As shown in Fig. 8, where the multiple exhaust openings 74 are formed on the rear surface 50b of the cell holder 50, an air flow from the front to the rear is generated along the longitudinal direction of the battery cells 48. As a result, the air that flows into the cell holder 50 from the multiple air supply openings 64, 66, 68, 70 flows left and right or up and down through the spaces between the multiple battery cells 48, then flows from the front to the rear and flows out of the cell holder 50 through the multiple exhaust openings 74. The air that flows out of the cell holder 50 through the multiple exhaust openings 74 flows out of the casing 12 through the multiple exhaust openings 42 on the rear surface 4b of the main body 4. The multiple battery cells 48 are cooled by the air flow as described above.

[0058] As described above, in one or more embodiments, the battery pack 2 is detachably attached to an electric device or a charger having an equipment-side terminal. The battery pack 2 includes a battery cell 48, a control circuit board 52 (an example of a circuit board) electrically connected to the battery cell 48, and a battery-side terminal 54 electrically connected to the control circuit board 52 and electrically connected to the equipment-side terminal by abutting against the equipment-side terminal. The battery-side terminal 54 includes a positive power supply terminal 78a and a negative power supply terminal 78b for discharging from the battery cell 48 or charging the battery cell 48, and at least one signal terminal 80 electrically connected to the control circuit board 52 and for signal communication with the control circuit board 52. The positive power supply terminal 78a is plated with a first metal on its surface. One of the at least one signal terminals 80 is plated with a second metal on its surface. The first metal is a pure metal other than Ag or an alloy not including Ag. The second metal is a pure metal belonging to the precious metals or an alloy of the precious metal.

[0059] According to the above configuration, the occurrence of short circuits due to ion migration and poor conduction due to fretting corrosion in the battery-side terminals 54 of the battery pack 2 can be suppressed.

[0060] In one or more embodiments, the negative power supply terminal 78b is plated on its surface with a third metal, the third metal being a pure metal other than Ag or an alloy that does not contain Ag.

[0061] According to the above configuration, the occurrence of a short circuit at the battery terminal 54 of the battery pack 2 due to ion migration can be suppressed.

[0062] In one or more embodiments, the third metal is the same metal as the first metal.

[0063] According to the above configuration, the positive power supply terminal 78a and the negative power supply terminal 78b can be plated in the same manner, so that the battery pack 2 can be manufactured more easily.

[0064] In one or more embodiments, at least one of the signal terminals 80 all have a second metal plated thereon.

[0065] According to the above-mentioned configuration, the plating process performed on all of at least one signal terminal 80 can be standardized, so that the battery pack 2 can be manufactured more easily.

[0066] In one or more embodiments, the first metal is Sn.

[0067] According to the above configuration, the slidability of the battery side terminals 54 that are plated with the first metal (e.g., the positive power terminal 78a, the negative power terminal 78b) when sliding against the device side terminals can be improved.

[0068] In one or more embodiments, the second metal is Ag.

[0069] According to the above configuration, the electrical resistance of those of the battery-side terminals 54 that are plated with the second metal (for example, the signal terminals 80) can be reduced. [Explanation of symbols]

[0070] 2: Battery pack 4: Main body 4a:Front 4b: Rear side 4c: Right side 4d: left side 4e:Top surface 4f: Bottom surface 6: Right support part 8:Left support part 10: Grip part 12: Casing 12a: Front casing 12b: Rear casing 14: Battery cell unit 16: Remaining battery indicator 17:Display circuit board 17a: Display switch 17b: LED 18: Remaining battery level display button 20: Terminal IF section 22: Terminal housing 24: Opening for terminal 26: First guide groove 28: Second guide groove 30: First guide groove 32: Second guide groove 34: Hook engagement groove 36: Air supply opening 38: Air supply opening 40: Air supply opening 42: Exhaust opening 44: Rib 44a: Bottom plate part 44b: Side plate part 46: Rib 46a: Bottom plate part 46b: Side plate part 48: Battery cell 48a: Positive electrode 48b: Negative electrode 50: Cell holder 50a:Front 50b: Rear side 50c: Right side 50d: left side 50e:Top surface 50f: Bottom surface 52: Control circuit board 54: Battery side terminal 56: Lead plate 58: Lead wire 60: Front cell holder 62: Rear cell holder 64: Air supply opening 66: Air supply opening 68: Air supply opening 70: Air supply opening 72: Electrode opening 74: Exhaust opening 76: Electrode opening 78: Power terminal 78a: Positive power supply terminal 78b: Negative power supply terminal 80: Signal terminal 80a: Charge / discharge control terminal 80b: Signal receiving terminal 80c: Overdischarge output terminal 80d: Signal transmission terminal 80e: Connection detection terminal 80f: Operation input terminal 82: Through hole 84: MPU 86: Power supply circuit 90: Temperature detection section 92: Current detection section 94: Charge / discharge control unit 96: Signal and Communication Department 98:Overdischarge output section 100: Operation input section 102: Connection detection unit

Claims

1. A battery pack that is detachable from an electrical device or a charger that has a device-side terminal, A battery cell; a circuit board electrically connected to the battery cell; a battery-side terminal electrically connected to the circuit board and electrically connected to the device-side terminal by contacting the device-side terminal; The battery side terminal is a positive power supply terminal and a negative power supply terminal for discharging from or charging the battery cell; a signal terminal electrically connected to the circuit board for signal communication with the circuit board; The positive power supply terminal has a surface plated with a first metal, All of the at least one signal terminals have a surface plated with a second metal, The first metal is Sn, The battery pack, wherein the second metal is a pure metal belonging to the precious metals or an alloy of precious metals.

2. The battery pack of claim 1, wherein the second metal is Ag.

3. A battery pack that is detachable from an electrical device or a charger that has a device-side terminal, A battery cell; a circuit board electrically connected to the battery cell; a battery-side terminal electrically connected to the circuit board and electrically connected to the device-side terminal by contacting the device-side terminal; The battery side terminal is a positive power supply terminal and a negative power supply terminal for discharging from or charging the battery cell; a signal terminal electrically connected to the circuit board for signal communication with the circuit board; The positive power supply terminal has a surface plated with a first metal, All of the at least one signal terminals have a surface plated with a second metal, the first metal is a pure metal other than Ag or an alloy not containing Ag, The battery pack, wherein the second metal is Ag.

4. The negative power supply terminal has a surface plated with a third metal, The battery pack according to claim 1 , wherein the third metal is a pure metal other than Ag or an alloy not containing Ag.

5. The battery pack of claim 4 , wherein the third metal is the same metal as the first metal.

Images