JP6327770B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack including an electrical laminate in which a plurality of thin plate-like battery cells are stacked.

  Non-aqueous electrolyte batteries typified by lithium-ion secondary batteries are characterized by high energy density. Therefore, various mobile devices such as cars and motorcycles, personal digital assistants, uninterruptible power supplies (UPSs), and electricity storage It is used as a power source for devices. In such applications, in order to further improve the energy density, a thin plate-like laminated lithium ion secondary battery in which a power generation element is packaged with a flexible laminate sheet is often used. Furthermore, in order to obtain a desired battery capacity, a battery stack in which a plurality of thin plate-like secondary batteries (battery cells) are stacked and these are connected in series is also in practical use (see, for example, Patent Document 1).

  A battery stack in which a plurality of battery cells are stacked is housed in a housing together with a circuit board to form a battery pack. The circuit board is provided with a power wiring and a protection circuit for connecting the battery stack and the external connection terminal. When the protection circuit detects an abnormality by an output from the current monitoring unit that monitors the current of the power wiring, the voltage monitoring unit that monitors the voltage of each battery cell constituting the battery stack, the current monitoring unit, and the voltage monitoring unit. A control unit that outputs a signal for shutting off the power wiring is provided. In a conventional battery pack, power wiring and various functional parts constituting a protection circuit are provided on a common substrate (see Patent Document 2).

Japanese Patent No. 4499977 JP 2012-89470 A (paragraphs [0059] to [0070], FIGS. 10 and 11)

  The demand for smaller and larger capacity battery packs is increasing day by day. In order to meet this demand, it is necessary to increase the current flowing through the power wiring while reducing the size of the substrate.

  However, if the width of the power wiring formed on the substrate is increased in order to increase the current of the power wiring, it becomes difficult to reduce the size of the substrate. Further, if the current of the power wiring is increased, the adverse effect of noise generated from the power wiring on the digital circuits constituting the voltage monitoring unit and the control unit cannot be ignored.

  An object of the present invention is to solve the above-described problems of conventional battery packs and to provide a battery pack that is reduced in size and increased in capacity.

  The battery pack of the present invention includes a battery stack in which a plurality of thin plate-like battery cells are stacked and the plurality of battery cells are connected in series, and a voltage monitoring unit that monitors each voltage of the plurality of battery cells; A power wiring that connects the battery stack and the external connection terminal, a current monitoring unit that monitors a current of the power wiring, a power unit that includes a switch that interrupts the power wiring, the voltage monitoring unit, and the current monitoring A control unit that receives a signal from the unit and outputs a signal for shutting off the power wiring to the switch. The power unit is provided on a power board different from the board on which the voltage monitoring unit and the control unit are provided. The wiring formed on the power substrate is thicker than the wiring formed on the substrate on which the voltage monitoring unit and the control unit are provided.

  According to the present invention, since the power unit is provided on a power board different from the board on which the voltage monitoring unit and the control unit are provided, noise generated from the power wiring configures the voltage monitoring unit and the control unit. The adverse effect on the digital circuit can be reduced. Moreover, since the wiring formed on the power board is thicker than the wiring formed on the board on which the voltage monitoring unit and the control unit are provided, a large current can flow through the power wiring without making the power wiring wide. . In addition, since it is not necessary to make the wiring of the substrate provided with the voltage monitoring unit and the control unit thicker than necessary, the substrate can be made thinner. As a result, it is possible to provide a battery pack that is reduced in size and increased in capacity.

FIG. 1A is a perspective view seen from the front side of a battery cell constituting a battery pack according to an embodiment of the present invention, and FIG. 1B is a perspective view seen from the back side thereof. FIG. 2 is an exploded perspective view of the battery stack constituting the battery pack according to the embodiment of the present invention. FIG. 3 is a block diagram showing a schematic configuration of the battery pack according to the embodiment of the present invention. FIG. 4 is a perspective view of a battery pack according to an embodiment of the present invention. FIG. 5 is a see-through perspective view of the main part of the battery pack according to the embodiment of the present invention, with the structure inside the cover and the intermediate frame seen through. FIG. 6 is a perspective view showing a state in which the power board is fixed to the intermediate frame in the assembly of the battery pack according to the embodiment of the present invention. 7 is a cross-sectional view corresponding to the vertical plane including line 7-7 in FIG. 6 showing a state immediately before the battery-power board connection step in the assembly of the battery pack according to the embodiment of the present invention. FIG. FIG. 8 is a cross-sectional view showing a state after the battery-power board connecting step in FIG.

  In the battery pack of the present invention, it is preferable that the power board and the board provided with the voltage monitoring unit and the control unit are stacked. Such a preferable configuration is advantageous for further downsizing of the entire substrate.

  The voltage monitoring unit and the control unit may be provided on different substrates. Thereby, the board | substrate (for example, multilayer board | substrate) suitable for each of a voltage monitoring part and a control part can be selected. In addition, the degree of freedom in designing with respect to the wiring circuit and component placement is improved. Therefore, such a preferable configuration is advantageous for further downsizing of the entire substrate.

  Leads electrically connected to the input / output tabs of the battery stack may face the power substrate. In this case, a screw penetrates the power board and the lead in this order, and is screwed with a nut disposed on the opposite side of the power board with respect to the lead. It is preferable to be electrically connected to the power wiring formed on the substrate. According to such a preferable configuration, the lead and the power wiring are not electrically connected until the screw and the nut are screwed together. Therefore, in the battery pack assembling operation, the process of screwing the screw and the nut is postponed, thereby reducing the possibility of an accident such as an electric shock or a short circuit when assembling the battery pack.

  In the above, it is preferable that the nut is housed in a cavity provided in a holding mechanism disposed on the side opposite to the power substrate with respect to the lead. Thereby, the operation | work which screws a screw and a nut can be performed easily and efficiently.

  In a state where the screw is not screwed with the nut, the lead is preferably separated from the power wiring. This can further reduce the possibility of accidents such as electric shocks and short circuits when assembling the battery pack.

  In a state where the screw is not screwed with the nut, the nut is preferably movable in a direction in which the nut comes in contact with and separates from the power board. Thereby, the structure in which the lead and the power wiring are electrically connected by screwing the screw and the nut can be easily realized.

  The battery pack may further include an upper lid that covers the power board. In this case, it is preferable that a through hole for inserting the screw is formed in the upper lid. Thereby, the process of screwing the screw and the nut can be performed as the final process after the power board is covered with the upper lid in the assembly operation of the battery pack. As a result, it is possible to further reduce the possibility of an accident such as an electric shock or a short circuit when assembling the battery pack.

  Below, this invention is demonstrated in detail, showing suitable embodiment. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the present invention can include any member not shown in the following drawings. In the following drawings, the actual dimensions of members and the dimensional ratios of the members are not faithfully represented. The suffixes “p” and “n” attached to each member mean “positive electrode” and “negative electrode”, respectively, unless otherwise specified.

<Battery cell>
The battery cell which comprises the battery pack concerning one Embodiment of this invention is demonstrated.

  1A is a perspective view seen from the front side of the battery cell 10, and FIG. 1B is a perspective view seen from the back side. The battery cell 10 has a substantially rectangular shape in plan view, and has a thin plate shape that is thinner than the vertical and horizontal dimensions of the substantially rectangular shape. In the battery cell 10, a thin plate-shaped power generation element (not shown) having a substantially rectangular plan view shape is enclosed in an exterior made of a laminate sheet 13 together with an electrolytic solution. The power generation element includes a positive electrode in which a positive electrode mixture layer including a positive electrode active material is applied and formed on both surfaces of a predetermined region of the positive electrode current collector, and a negative electrode mixture layer including a negative electrode active material on both surfaces of the predetermined region of the negative electrode current collector Is an electrode laminate in which negative electrodes formed by coating are alternately laminated via separators. The type of the battery is not particularly limited, but a secondary battery, particularly a lithium ion secondary battery is preferable.

  The laminate sheet 13 is thinner than the power generation element and has flexibility. The laminate sheet 13 may be a flexible multilayer sheet in which a heat-fusible resin layer (for example, a modified polyolefin layer) is laminated on the surface of the base layer made of aluminum or the like on the side facing the power generation element. Good. One rectangular laminate sheet 13 is folded in two at the lower side (one short side) 14b so as to sandwich the power generation element, is overlapped along three sides other than the lower side 14b, and is sealed by a heat sealing method or the like. Yes.

  A positive electrode tab 11p and a negative electrode tab 11n are led out from an upper side (the other short side) 14a facing the lower side 14b. The positive electrode tab 11p and the negative electrode tab 11n have a strip shape and extend along a direction orthogonal to the upper side 14a (that is, a direction parallel to a pair of side sides (long sides) 14s adjacent to the upper side 14a). Yes. The positive electrode tab 11p is made of, for example, an aluminum thin plate, and is electrically connected to a plurality of positive electrode current collectors (not shown) constituting the power generation element. The negative electrode tab 11n is made of, for example, a copper thin plate, a nickel-plated copper thin plate, or a copper / nickel clad material, and is electrically connected to a plurality of negative electrode current collectors (not shown) constituting the power generation element. It is connected to the.

  As shown in FIG. 1A, a rectangular region 16 corresponding to the power generation element protrudes from the sealing region of the laminate sheet 13 along the three sides 14 a, 14 s and 14 s of the battery cell 10. The surface from which the region 16 protrudes is referred to as the “front surface” of the battery cell 10. On the other hand, as shown in FIG. 1B, the surface on the opposite side from the front surface that forms a substantially flat surface is referred to as the “back surface” of the battery cell 10.

  In the present invention, the configuration of the battery cell is not limited to the above. For example, a battery cell of a four-side seal type in which a power generation element is sandwiched between two rectangular laminate sheets and two laminate sheets are sealed along four sides may be used.

<Battery laminate>
FIG. 2 is an exploded perspective view of the battery stack 20 constituting the battery pack according to the embodiment of the present invention. The battery stack 20 is configured by stacking a plurality of battery cells 10. A direction in which the battery cells 10 are stacked (lateral direction in FIG. 2) is referred to as a “stacking direction”.

  As shown in FIG. 2, the plurality of battery cells 10 are arranged so that tabs of different polarities (that is, positive electrode tab 11p and negative electrode tab 11n) face each other in the stacking direction between two adjacent battery cells 10. Every other battery cell 10 is turned over. As indicated by a two-dot chain line 23, the positive electrode tab 11p and the negative electrode tab 11n facing each other in the stacking direction are electrically connected. As a result, the plurality of battery cells 10 are connected in series. A voltage monitoring wiring 22 is connected to the positive electrode tab 11p and the negative electrode tab 11n connected to each other. The positive electrode tab 11 p ′ and the negative electrode tab 11 n ′ at both ends that are not connected to the different polarity tab serve as input / output tabs for inputting / outputting power to / from the battery stack 20.

  The battery cells 10 adjacent in the stacking direction are integrated using, for example, a double-sided adhesive tape. A thin plate material (not shown) may be interposed between adjacent battery cells 10. The number of battery cells 10 constituting the battery stack 20 is arbitrary.

<Battery pack>
FIG. 3 is a block diagram showing a schematic configuration of the battery pack 1 according to the embodiment of the present invention.

  A plurality of voltage monitoring wires 22 (see FIG. 2) connected to the battery stack 20 are connected to the voltage monitoring unit 3.

  The input / output tabs 11p 'and 11n' of the battery stack 20 are connected to external connection terminals 42p and 42n for inputting / outputting power to / from the battery pack 1 via power wirings 41p and 41n. On the positive power line 41p, a switch 43 for connecting and disconnecting the positive power line 41p is provided. On the other hand, a current monitoring unit 44 that monitors the current flowing through the negative power line 41n is provided on the negative power line 41n. The switch 43 includes a switch that switches electrical connection of the positive power line 41p and a driver circuit that drives the switch. Unlike the present embodiment, the current monitoring unit 44 may be provided on the positive power line 41p, and the switch 43 may be provided on the negative power line 41n. The switch 43 and the current monitoring unit 44 may be provided on one of the positive power line 41p and the negative power line 41n. The power wirings 41 p and 41 n, the external connection terminals 42 p and 42 n, the switch 43, and the current monitoring unit 44 constitute the power unit 4.

  The voltage monitoring unit 3 is connected to the control unit 5. When the control unit 5 detects that the voltage of the battery cell 10 is abnormal based on a signal from the voltage monitoring unit 3, the control unit 5 outputs a signal for cutting off the power wiring 41 p to the switch 43, and sends the signal to the battery stack 20 and the battery pack 1. Cut off the electrical connection with the connected equipment.

  The current monitoring unit 44 is also connected to the control unit 5. When the control unit 5 detects that the current flowing through the power wiring is abnormal based on the signal from the current monitoring unit 44, the control unit 5 outputs a signal for cutting off the power wiring 41 p to the switch 43, and the battery stack 20 and the battery pack 1. Cut off the electrical connection with the outside.

  Although not shown, the voltage monitoring unit 3, the switch 43, the current monitoring unit 44, and the control unit 5 are supplied with power from the battery stack 20 in order to perform their functions.

  How the configuration shown in FIG. 3 is embodied in the actual battery pack 1 will be described below.

  FIG. 4 is a perspective view of the battery pack 1. The battery pack 1 has a case 60 provided with a case main body 61, an intermediate frame 62, and an upper lid 63 in this order. On the upper surface of the upper lid 63, a positive external connection terminal 42p and a negative external connection terminal 42n for inputting / outputting electric power to / from the battery pack 1 are provided.

  FIG. 5 is a perspective view of the main part of the battery pack 1 as seen through the internal structure of the upper lid 63 and the intermediate frame 62. The case main body 61 is a bottomed box body having a substantially rectangular parallelepiped shape and opened upward. The battery stack 20 (see FIG. 2) is accommodated in the case main body 61. A voltage monitoring board 73 is fixed to the case body 61 so as to close the opening of the case body 61. A power board 74 and a control board 75 are arranged above the voltage monitoring board 73. The voltage monitoring unit 3, the power unit 4, and the control unit 5 described in FIG. 3 are sequentially provided on the voltage monitoring board 73, the power board 74, and the control board 75.

  The voltage monitoring board 73 has a substantially rectangular plan view shape. Of the four sides around the voltage monitoring board 73, first notches 31p and 31n are formed on one opposite two sides, and a plurality of second notches 32 are formed on each of the other two opposite sides. Is formed.

  The strip-shaped electrode leads 21p and 21n connected to the input / output tabs 11p ′ and 11n ′ (see FIG. 2) of the battery stack 20 through the pair of first cutouts 31p and 31n are connected to the voltage monitoring board 73. It is guided from the lower side (battery laminate 20 side) to the upper side. The electrode leads 21p and 21n are fixed to terminal blocks 33p and 33n mounted on the voltage monitoring board 73. One end of strip-like connection leads 45p and 45n (the positive electrode connection lead 45p is not visible in FIG. 5) is connected to the terminal blocks 33p and 33n. Thereby, the connection leads 45p and 45n are electrically connected to the electrode leads 21p and 21n via the terminal blocks 33p and 33n. The other ends of the connection leads 45p and 45n are electrically connected to the power board 74 (see FIG. 8 described later).

  The second notches 32 are formed at a substantially constant pitch along the side of the electrode monitoring substrate 73. The terminal 35 is mounted at a position in the vicinity of the second notch 32 on the electrode monitoring board 73. A plurality of terminals 35 are provided in one-to-one correspondence with the second notches 32. One voltage monitoring wiring 22 (see FIG. 2) connected to the battery stack 20 through each second notch 32 is above the lower side of the voltage monitoring board 73 (battery stack 20 side). It is guided to. The wiring 22 is connected to a terminal 35 corresponding to the second notch 32 that guides the wiring 22.

  On the voltage monitoring board 73, a voltage monitoring circuit (for example, IC) 36 for monitoring the voltage of each battery cell 10 constituting the battery stack 20 is mounted. The voltage monitoring circuit 36 is connected to a plurality of terminals 35 via wiring (not shown) formed on the voltage monitoring substrate 73. The voltage monitoring circuit 36 constitutes a voltage monitoring unit 3 (see FIG. 3) that monitors the voltage of each battery cell 10.

  The power board 74 is disposed above the voltage monitoring board 73 so as to be separated therefrom. External connection terminals 42p and 42n (see FIG. 3) for inputting / outputting electric power to / from the battery pack 1 are mounted on the power board 74. Power wirings 41p and 41n (see FIG. 3, not shown in FIG. 5) for connecting the connection leads 45p and 45n and the external connection terminals 42p and 42n are formed on the surface of the power substrate 74 or inside thereof. Further, the power board 74 is equipped with a switch circuit (for example, IC) 43a constituting the switch 43 (see FIG. 3) and a current monitoring circuit (for example, IC) 44a constituting the current monitoring unit 44 (see FIG. 3). Has been.

  The control board 75 is disposed above the power board 74 and spaced from the power board 74. On the control board 75, a control circuit (for example, IC) 51 constituting the control unit 5 (see FIG. 3) is mounted.

  The voltage monitoring board 73, the power board 74, and the control board 75 are electrically connected to each other with a flexible cable (not shown).

<Action>
The operation of the battery pack 1 of the present embodiment will be described in comparison with a conventional battery pack.

  As described above, in recent years, there has been an increasing demand for smaller and larger capacity battery packs. In order to increase the capacity of the battery pack, it is necessary to increase the current of the power wiring that connects the battery stack and the external connection terminal. This increases the noise generated from the power wiring. In the conventional battery pack, since the power wiring and the protection circuit including the voltage monitoring unit and the control unit are provided on the same substrate, the digital circuit constituting the voltage monitoring unit and the control unit by noise from the power wiring Could have an adverse effect on In order to avoid the adverse effects of noise, it is necessary to separate the power wiring from the voltage monitoring unit and the control unit, which increases the substrate area and makes it difficult to reduce the size of the battery pack.

  On the other hand, in the battery pack 1 of this embodiment, the power unit 4 including the power wirings 41p and 41n includes the voltage monitoring board 73 provided with the voltage monitoring unit 3 and the control board 75 provided with the control unit 5. Are provided on another power board 74. Therefore, the distance between the power unit 4 and the voltage monitoring unit 3 and the control unit 5 can be easily increased. Moreover, a shield can be provided between the power unit 4 and the voltage monitoring unit 3 and the control unit 5 as necessary. As a result, it is possible to reduce the possibility that the digital circuits constituting the voltage monitoring unit 3 and the control unit 5 will be adversely affected by noise from the power unit 4.

  By dividing the substrate, the degree of freedom of design related to the arrangement of the wiring formed on each substrate and the components mounted on the substrate is improved. This is advantageous for downsizing the entire substrate as compared to the conventional configuration using a single substrate.

  As the substrate of the battery pack, a so-called multilayer substrate in which a plurality of layers of wiring (wiring patterns) are formed in a predetermined pattern on the surface and inside is generally used. In a multilayer substrate, the thickness of wiring in each layer (the dimension along the direction perpendicular to the surface of the substrate) is usually the same. In the conventional battery pack, the power wiring and the protection circuit including the voltage monitoring unit and the control unit are provided on the same substrate. When a multilayer substrate with thick wiring is used to increase the current of the power wiring, such a thick wiring is wasted in the voltage monitoring unit and the control unit, and the multilayer substrate becomes thick. On the other hand, when a multilayer substrate with a wide wiring is used to increase the current of the power wiring, the substrate area increases.

  On the other hand, in the battery pack 1 of this embodiment, the power unit 4 including the power wirings 41p and 41n includes the voltage monitoring board 73 provided with the voltage monitoring unit 3 and the control board 75 provided with the control unit 5. Are provided on another power board 74. Accordingly, an optimum multilayer substrate can be used as each of the substrates 73, 74, and 75. For example, a multilayer substrate having a thick wiring can be used as the power substrate 74 in order to increase the current of the power wirings 41p and 41n. As a result, an increase in the width of the wiring (a dimension along a direction parallel to the surface of the substrate) can be suppressed, so that an increase in the substrate area can be avoided. On the other hand, as the voltage monitoring board 73 and the control board 75 that do not require a large current, a multilayer board having a relatively small wiring thickness and width can be used. As a result, the substrates 73 and 75 can be made thinner and smaller in area. In one embodiment, a multilayer substrate having a total thickness of 2.3 mm on which a wiring having a thickness of 300 μm is formed can be used as the power substrate 74, and a wiring having a thickness of 35 μm can be used as the voltage monitoring substrate 73. A two-layer substrate having a total thickness of 1.5 mm can be used, and a six-layer substrate having a total thickness of 1.5 mm and a wiring having a thickness of 35 μm formed as the control substrate 75. Can be used.

  As described above, according to the present embodiment, the power unit 4 is provided on the power board 74 different from the boards 73 and 75 on which the voltage monitoring unit 3 and the control unit 5 are provided, and the power board 74 is provided. The wiring formed on the substrate is thicker than the wiring formed on the substrates 73 and 75 on which the voltage monitoring unit 3 and the control unit 5 are provided. Thereby, size reduction and capacity increase of the battery pack 1 can be realized.

  Further, by stacking the three substrates 73, 74, 75, the substrates 73, 74, 75 can be downsized as a whole while avoiding the above-mentioned noise problem. Note that the order of stacking the substrates 73, 74, and 75 is not limited to the above embodiment, and can be arbitrarily changed.

  Further, the protection circuit is divided into a plurality of parts with attention paid to the function, and each part is mounted on a separate substrate, whereby each part of the protection circuit can be modularized. As a result, it becomes easy to change the design or replace only a part of the plurality of substrates constituting the protection circuit, so that it is possible to easily cope with a wide variety of battery packs. Further, the protection circuit can be repaired by exchanging only a part of the substrates.

<Connection between battery stack and power wiring>
When the battery pack 1 is assembled, the input / output tabs 11p ′ and 11n ′ (see FIG. 2) of the battery stack 20 and the power wirings 41p and 41n (see FIG. 3) are electrically connected at any stage. It is necessary to perform a process (hereinafter referred to as “battery-power board connection process”). If the battery-power board connection process is performed at an early stage, there is a high possibility that an accident such as an electric shock or a short circuit will occur in the subsequent assembly process. When the capacity (voltage) of the battery stack 20 is high, damage due to such an accident can be significant. Furthermore, when using a plurality of substrates as in the present embodiment, the assembly process of the battery pack 1 becomes complicated, and thus there is a high possibility that such an accident will occur.

  In the battery pack 1 of the present embodiment, a structure that reduces the possibility of such an accident is employed. This will be described below.

  The battery pack 1 of the present embodiment is generally assembled through the following steps in order. (1) The battery stack 20 is stored in the case body 61. (2) The voltage monitoring board 73 is fixed to the case body 61, and the battery stack 20 and the voltage monitoring board 73 are connected. (3) The intermediate frame 62 is fixed to the case body 61. (4) The power board 74 is fixed to the intermediate frame 62. (5) The upper lid 63 on which the control board 75 is mounted is fixed to the intermediate frame 62.

  FIG. 6 is a perspective view showing a state in which the power board 74 is fixed to the intermediate frame 62 (the step (4)) in the above assembly. Thereafter, the upper lid 63 is fixed to the intermediate frame 62 so as to cover the power substrate 74 (step (5) above). FIG. 7 is a cross-sectional view taken along the cross-section corresponding to the vertical plane including the line 7-7 in FIG. 6, showing a state in which the upper lid 63 is fixed. In FIG. 7, in order to simplify the drawing, members that are visible behind the cross section are omitted.

  As shown in FIG. 7, a terminal block 33 n having conductivity is mounted on the voltage monitoring board 73. The electrode lead 21n connected to the input / output tab 11n '(see FIG. 2) of the battery stack 20 is fixed to the terminal block 33n with a screw 47a. The lower end of the connection lead 45n bent in a substantially Z shape is tightly fixed to the terminal block 33n with a screw 47b. Therefore, the electrode lead 21n and the connection lead 45n are electrically connected via the terminal block 33n. The terminal block 33n may have an insulating property. In that case, a conductive layer is formed on the upper surface of the terminal block 33n, and the electrode lead 21n and the connection lead 45n are electrically connected via the conductive layer. Can be connected.

  The intermediate frame 62 has a holding portion 65 in the vicinity of the terminal block 33n. The holding part 65 has a bottomed box shape with the upper part opened, and holds the nut 48 in the cavity 66 therein. Within the cavity 66, the nut 48 can move in the vertical direction (the direction in which it is in contact with and away from the power board 74). The upper end of the connection lead 45n extends in the horizontal direction so as to close the opening of the holding portion 65. At the upper end of the connection lead 45n, a through hole 46 that penetrates the connection lead 45n is formed at a position substantially coaxial with the nut 48. Further, the power board 74 is also formed with a through-hole 77 that penetrates the power board 74 at a position substantially coaxial with the nut 48. A wiring terminal 41t made of a conductive metal is formed on the lower surface of the power substrate 74 and in a region facing the upper end of the connection lead 45n. The wiring terminal 41 t surrounds the opening of the through hole 77. The wiring terminal 41t forms part of the power wiring 41n (see FIG. 3). The connection lead 45n and the wiring terminal 41t are separated from each other. An upper lid 63 covers the power board 74. A through hole 68 penetrating the upper lid 63 is formed in the upper lid 63 at a position substantially coaxial with the nut 48.

  When performing the battery-power board connecting step of connecting the input / output tab 11n ′ of the battery stack 20 and the power wiring 41n, the screw 49 is inserted into the through hole 68 formed in the upper lid 63 from above (FIG. 8). The screw 49 is passed through the through hole 68 of the upper lid 63, the through hole 77 of the power board 74, and the through hole 46 of the connection lead 45n in this order, and is screwed into the nut 48 held by the holding portion 65. Since the regular hexagonal cylinder surface on the outer periphery of the nut 48 contacts the inner peripheral surface of the cavity 66 of the holding portion 65, the rotation of the nut 48 is prevented. As the screw 49 and the nut 48 are screwed together, the nut 48 is lifted upward, and the connection lead 45n is lifted accordingly. Finally, as shown in FIG. 8, the screw 49 and the nut 48 are firmly fastened. As a result, the connection lead 45n and the wiring terminal 41t of the power wiring 41n are brought into close contact with each other and electrically connected, and the battery-power board connecting step is completed.

  The above description relates to the electrical connection on the negative electrode side between the input / output tab of the battery stack 20 and the power wiring, but the electrical connection on the positive electrode side is the same as described above.

  Thus, in the present embodiment, the connection leads 45p and 45n and the power wirings 41p and 41n that are electrically connected to the input / output tabs 11p ′ and 11n ′ of the battery stack 20 can be obtained only by attaching the upper lid 63 to the intermediate frame 62. Not electrically connected. By inserting a screw 49 into the through hole 68 from above the upper lid 63 and screwing it into the nut 48 held on the lower side of the power board 74, the battery-power board connecting step is completed. According to the present embodiment, the substrates 73, 74 and 75 can be assembled in a state where they are not electrically connected to the input / output tabs 11 p ′ and 11 n ′ of the battery stack 20. The battery-power board connecting step is performed after the upper lid 63 is fixed, that is, as the final step of the assembling operation of the battery pack 1. As a result, it is possible to reduce the possibility of an accident such as an electric shock or a short circuit in the assembling work of the substrates 73, 74, and 75. The through hole 68 of the upper lid 63 may be closed by attaching a label to the upper lid 63 or inserting a plug into the through hole 68 as necessary after performing the battery-power board connection step.

  In this embodiment, the nut 48 is held so as to be movable in the vertical direction in the cavity 66 of the holding portion 65 before being screwed with the screw 49. In this configuration, the nut 48 may be stored in the cavity 66 of the holding portion 65 before the power board 74 is attached to the intermediate frame 62. Since the nut 48 is held by the holding portion 65, if the screw 49 is inserted into the through hole 77 of the power board 74 and rotated, the screw 49 and the nut 48 can be easily screwed together. Thereby, a battery-power board connection process can be performed efficiently.

  The above embodiments are merely examples. The present invention is not limited to the above embodiment and can be variously modified.

  For example, in the above-described embodiment, the voltage monitoring unit 3 and the control unit 5 are stacked in the vertical direction, but these may be arranged along the same horizontal plane. The voltage monitoring unit 3 and the control unit 5 may be provided on a common substrate instead of being provided on separate substrates. Further, at least one of the voltage monitoring unit 3, the power unit 4, and the control unit 5 may be divided into two or more and provided on separate substrates.

  In the above embodiment, the input / output tabs 11p ′ and 11n ′ of the battery stack 20 are connected to the power wirings 41p and 41n via the electrode leads 21p and 21n and the connection leads 45p and 45n. , 21n and one or both of the connection leads 45p, 45n may be omitted. Alternatively, other members may be further interposed between the input / output tabs 11p 'and 11n' and the power wirings 41p and 41n.

  In the above embodiment, the terminal blocks 33p and 33n provided on the voltage monitoring board 73 are interposed between the input / output tabs 11p ′ and 11n ′ and the power wirings 41p and 41n. Omitted, the electrode leads 21p and 21n (or any leads connected to the input / output tabs 11p ′ and 11n ′) may be connected to the power wirings 41p and 41n of the power board 74.

  The holding portion 65 that holds the nut 48 need not be provided in the intermediate frame 62. For example, the holding unit 65 may be provided on the voltage monitoring board 73 or the power board 74. The holding portion 65 may be omitted, and the operator may screw the nut 48 and the screw 49 while holding the nut 48.

  The protection circuit of the battery pack may further include a temperature monitoring unit that monitors the temperature of the battery cell. In this case, when the control unit 5 detects that the temperature of the battery cell is abnormal based on a signal from the temperature monitoring unit, the control unit 5 outputs a signal for cutting off the power wiring to the switch 43, so that the battery stack 20 and the battery pack 1 The electrical connection with the outside can be cut off. Such a temperature monitoring unit is preferably provided on a substrate other than the power substrate 74.

  The configuration of the case is not limited to the above embodiment, and is arbitrary. For example, the intermediate frame 62 may be omitted.

  The upper lid 63 may not have the through hole 68 for inserting the screw 49. In this case, the battery-power board connecting step can be performed immediately before the step of fixing the upper lid 63 to the intermediate frame 62 (the above step (5)). Also in this case, the battery-power board connection step can be performed after all the electrical connections necessary for assembling the battery pack 1 are completed except for the connection between the connection leads 45p, 45n and the power wirings 41p, 41n. it can. Thereby, until just before the battery-power board connection step, the boards 73, 74, and 75 can be assembled without being electrically connected to the input / output tabs 11 p ′ and 11 n ′ of the battery stack 20. As a result, it is possible to reduce the possibility of an accident such as an electric shock or a short circuit in the assembling work of the substrates 73, 74, and 75.

  In the above embodiment, the control board 75 is attached to the upper lid 63. However, the present invention is not limited to this, and the control board 75 may be configured to be fixed to the power board 74. In this case, after fixing the control board 75 to the power board 74, the upper lid 63 is fixed to the fixed frame 62 so as to cover the control board 75 and the power board 74.

  In the above description, the upper and lower directions and the horizontal direction of the battery pack 1 are described with the upper lid 63 side as the upper side of the battery pack 1 and the case body 61 side as the lower side of the battery pack 1, but this is only for convenience of description. . The direction of actual use of the battery pack is not limited to this.

  The field of application of the present invention is not particularly limited, and is widely used as a battery pack used as a power source for various mobile devices such as automobiles, motorcycles, and electrically assisted bicycles, personal digital assistants, uninterruptible power supplies (UPS), and power storage devices. Can be used.

DESCRIPTION OF SYMBOLS 1 Battery pack 3 Voltage monitoring part 4 Power part 5 Control part 10 Battery cell 11p ', 11n' Input / output tab 20 Battery laminated body 22 Voltage monitoring wiring 41p, 41n Power wiring 42p, 42n External connection terminal 43 Switch 44 Current monitoring 45p, 45n Connection lead (lead)
48 Nut 49 Screw 63 Upper lid 65 Holding part (holding mechanism)
66 Cavity 68 Through-hole 73 Voltage monitoring board 74 Power board 75 Control board

Claims (5)

A battery stack in which a plurality of thin battery cells are stacked and the plurality of battery cells are connected in series;
A power board provided with a power wiring connecting the battery laminate and the external connection terminal,
The lead electrically connected to the input / output tab of the battery stack is opposed to the power board,
A screw penetrates the power board and the lead in this order and is screwed with a nut disposed on the opposite side of the power board to the lead, whereby the lead is formed on the power board. A battery pack, wherein the battery pack is electrically connected to the power wiring.   The battery pack according to claim 1, wherein the nut is housed in a cavity provided in a holding mechanism disposed on the opposite side of the power substrate from the lead.   The battery pack according to claim 1, wherein the lead is separated from the power wiring in a state where the screw is not screwed with the nut.   The battery pack according to any one of claims 1 to 3, wherein the nut is movable in a direction in which the screw is in contact with or separated from the power board in a state where the screw is not screwed into the nut. Further comprising an upper lid covering the power substrate,
The battery pack according to claim 1, wherein a through hole for inserting the screw is formed in the upper lid.

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