JP6081866B2 - 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 and a circuit board.

  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. A protection circuit is mounted on the circuit board. A protection circuit monitors the voltage of each battery cell which comprises a battery laminated body, and if an abnormality is detected, it will interrupt | block the electrical connection of a battery laminated body and the exterior. In order to monitor the voltage of each battery cell, a voltage monitoring wiring (wire) is connected to a connection portion between a positive electrode tab and a negative electrode tab which are electrically connected to adjacent battery cells. The end of the wiring is connected to a terminal provided on the circuit board (see, for example, Patent Document 2).

Japanese Patent No. 4499977 JP 2012-89470 A

  In general, a battery pack is provided with a plurality of voltage monitoring wires. The plurality of wirings are sequentially connected to a plurality of terminals arranged along a straight line on the circuit board. Wiring may be broken by vibration or impact applied during transportation or use of the battery pack. In this case, the broken wiring may come into contact with a nearby wiring or terminal and short-circuit. The short circuit causes abnormal heat generation of the battery cell, and in the worst case, smoke or fire occurs.

  An object of the present invention is to provide a highly safe battery pack in which the possibility of a short circuit accident occurring even when a voltage monitoring wiring breaks is reduced.

  The battery pack according to 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 plurality of terminals on a surface opposite to the battery stack. A plurality of voltage monitoring wires that are derived from the battery stack and are electrically connected to the plurality of terminals, respectively, and a cover that covers at least the plurality of terminals and the plurality of wires. Prepare. A partition plate is erected on the cover. A plurality of spaces are defined by the partition plate. A part of each of the plurality of wirings connected to the plurality of terminals is housed in each of the plurality of spaces.

  In the present invention, a part of each wiring is accommodated in a space defined by the partition plate. Accordingly, even if the wiring breaks, the wiring restricts the displacement of the partition plate, so that the broken wiring does not protrude beyond the space corresponding to the wiring and does not contact the adjacent wiring or the like. As a result, according to the present invention, it is possible to provide a highly safe battery pack in which the possibility of a short circuit accident occurring even when the voltage monitoring wiring is broken is reduced.

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 perspective view of the battery stack constituting 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 an exploded perspective view of the battery pack according to the embodiment of the present invention. FIG. 6 is a plan view of a circuit board constituting the battery pack according to the embodiment of the present invention. FIG. 7 is a perspective view seen from the lower surface side of the cover constituting the battery pack according to the embodiment of the present invention. FIG. 8 is a cutaway perspective view showing voltage monitoring wiring housed in a space between partition plates formed on the cover in the battery pack according to the embodiment of the present invention. FIG. 9 is a perspective view seen from the lower surface side of the cover constituting the battery pack according to the comparative example. FIG. 10 is a cutaway perspective view showing voltage monitoring wires housed in a space between partition plates formed on the cover in the battery pack according to the comparative example. FIG. 11 is a cutaway perspective view showing a state in which a broken wire is short-circuited to an adjacent wire in the battery pack according to the comparative example shown in FIG. 10. FIG. 12 is a cutaway perspective view showing a state in which the wiring is broken in the battery pack according to the embodiment of the present invention shown in FIG. 8.

  In the battery pack of the present invention, the plurality of terminals may be arranged on a straight line. In this case, it is preferable that a plurality of the partition plates are arranged apart from each other along a direction parallel to the straight line. By arranging the plurality of terminals on a straight line, it is possible to guide a plurality of wirings for voltage monitoring from the battery stack to the plurality of terminals without contacting each other. In such a case, even if one of the plurality of wirings breaks by disposing the plurality of partition plates in parallel with the arrangement direction of the plurality of terminals, the broken wiring is adjacent to each other. The possibility of short-circuiting with the wiring can be efficiently reduced with a simple partition plate configuration.

  In the above, the partition plate that connects the plurality of partition plates and is parallel to the straight line may be erected on the cover. Accordingly, the screen plate prevents the broken wiring from being short-circuited with various components and the wiring circuit on the circuit board. Therefore, it is possible to further reduce the possibility that a short circuit accident will occur due to the breakage of the wiring.

  A position regulating mechanism for regulating the position of the wiring in a direction parallel to the circuit board may be formed on the circuit board. Thereby, since the position restricting mechanism regulates the position of the broken wiring, the possibility that the broken wiring protrudes outside the space corresponding to the wiring and contacts the adjacent wiring or the like can be further reduced.

  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. Further, in the following drawings, the actual dimensions of the members and the dimensional ratios of the members are not faithfully represented.

<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. The direction in which the battery cells 10 are stacked (lateral direction in FIG. 2) is referred to as “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. 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 electric power to / from the battery stack 20.

  FIG. 3 is a perspective view of the battery stack 20. The battery stack 20 of the present embodiment is composed of 14 battery cells 10 connected in series. Although not shown, a thin plate material may be interposed between adjacent battery cells 10. The material of the plate material is arbitrary, but for example, a resin material having insulation properties such as polycarbonate can be used for the purpose of improving insulation between the battery cells 10, and copper for the purpose of improving heat dissipation, A metal material having excellent thermal conductivity such as aluminum can be used. Adjacent battery cells 10 (and the plate material therebetween) are integrated using, for example, a double-sided adhesive tape.

  The positive electrode tab 11p and the negative electrode tab 11n facing each other in the stacking direction are electrically connected to form a tab connection portion 11c. The battery stack 20 of the present embodiment has 13 tab connecting portions 11c. Six tab connection portions 11c are arranged along a straight line connecting the input / output positive electrode tab 11p ′ and the input / output negative electrode tab 11n ′, and the seven tab connection portions 11c are arranged along a straight line parallel to the straight line. Has been placed. Voltage monitoring wiring (wiring 22 shown in FIG. 5 described later) is connected to each of the 13 tab connecting portions 11c. The tab connecting portion 11c may be folded downward in FIG.

<Battery pack>
FIG. 4 is a perspective view of the battery pack 1 according to the embodiment of the present invention, and FIG. 5 is an exploded perspective view of the battery pack 1. For the convenience of the following description, the vertical direction of the paper surface of FIG. However, the “vertical direction” and “horizontal direction” do not mean the direction in which the battery pack 1 is actually used.

  As shown in FIG. 5, the battery stack 20 is housed in a housing 30 having a hollow, substantially rectangular parallelepiped shape that is open at the top. 21p is a strip-like positive electrode lead connected to the input / output positive electrode tab 11p ′ (see FIG. 3) of the battery stack 20, and 21n is the input / output negative electrode tab 11n ′ of the battery stack 20 (FIG. 3). A strip-like negative electrode lead connected to the reference). Reference numeral 22 denotes a voltage monitoring wire (wire) connected to the tab connecting portion 11c (see FIG. 3) of the battery stack 20. In FIG. 5, in order to simplify the drawing, the illustration of the battery cell 10 constituting the battery stack 20 and the positive electrode tab 11p and the negative electrode tab 11n led upward therefrom is omitted, and the upper surface of the battery stack 20 is illustrated. Is shown in one plane.

  The circuit board 40 is fitted into the housing 30 and fixed so as to close the upper opening of the housing 30. FIG. 6 is a plan view of the circuit board 40. The circuit board 40 is a plate-like member having a substantially rectangular plan view shape. On the surface (upper surface) opposite to the battery stack 20 of the circuit board 40, a protection circuit (for example, IC) 41, a plurality (13 in this embodiment) of terminals 42, a positive terminal 45p, a negative terminal 45n, an input An output terminal box 47 and the like are mounted. The terminal 42, the positive terminal 45p, the negative terminal 45n, and the terminal box 47 are connected to the protection circuit 41 via a wiring circuit (not shown) formed on or in the circuit board 40.

  Six of the thirteen terminals 42 are arranged at a constant pitch along the side edge 40a of the circuit board 40, and the remaining seven are arranged at a constant pitch along the side edge 40b opposite to the side edge 40a. Has been. Thirteen substantially L-shaped notches 43 are formed in the circuit board 40. The notches 43 and the terminals 42 correspond one to one, and the notches 43 are formed in the vicinity of the corresponding terminals 42. Each notch 43 is open to the side end 40 a or 40 b of the circuit board 40. The voltage monitoring wiring 22 is locked to the notch 42, guided above the circuit board 40, and connected to the terminal 42 (see FIG. 8 described later). The connection method of the wiring 22 and the terminal 42 is arbitrary. In this embodiment, the wiring 22 and the terminal 42 are connected by inserting the male connector (not shown) attached to the terminal (upper end) of the wiring 22 into the terminal 42 that functions as a female connector. However, other methods such as a known method such as soldering may be used.

  The positive electrode lead 21p and the negative electrode lead 21n are inserted into slit-like openings 46p and openings 46n that penetrate the circuit board 40, and are connected to the positive electrode terminal 45p and the negative electrode terminal 45n, respectively.

  Although not shown, the terminal box 47 includes a positive terminal and a negative terminal, and is used to input and output power to the battery pack 1.

  Returning to FIG. 5, the cover 50 is placed from above the circuit board 40 and fixed to the housing 30. As shown in FIG. 4, the circuit board 40 is covered with a cover 50.

  FIG. 7 is a perspective view of the cover 50 as viewed from the lower surface (the surface facing the circuit board 40). A plurality (11 in the present embodiment) of partition plates 51 are erected from the top plate 53 of the cover 50. Five partition plates 51 are arranged at a constant pitch along the side wall 50a parallel to the vertical direction of the cover 50, and six partition plates 51 are arranged at a constant pitch along the side wall 50b facing the side wall 50a of the cover 50. Has been. The pitch of the partition plates 51 is the same as the pitch of the terminals 42 provided on the circuit board 40.

  The five partition plates 51 along the side wall 50a are all connected to the side wall 50a and are perpendicular to the side wall 50a. A partition plate 52a connecting the five partition plates 51 is erected from the top plate 53 so as to face and be parallel to the side wall 50a. Six spaces 55 partitioned by five partition plates 51 are formed between the partition plate 52a and the side wall 50a.

  Similarly, the six partition plates 51 along the side wall 50b are all connected to the side wall 50b and are perpendicular to the side wall 50b. A partition plate 52b connecting the six partition plates 51 is erected from the top plate 53 so as to face and be parallel to the side wall 50b. Seven spaces 55 defined by six partition plates 51 are formed between the partition plate 52b and the side wall 50b.

  FIG. 8 is an enlarged perspective view showing the terminal 42, the notch 43, the wiring 22, the partition plate 51, and the like as seen from the side wall 50a. In order to show these members in the cover 50, a part of the side wall 50a and the top plate 53 is notched.

  The lower end of the partition plate 51 and the circuit board 40 are slightly separated from each other. One terminal 42 and one notch 43 are arranged corresponding to each space 55 defined by the partition plate 51. The wiring 22 is locked to the notch 43, extends from the lower side to the upper side of the circuit board 40, is bent downward, and is connected to the terminal 42. At least a curved portion of the wiring 22 is accommodated in the space 55.

  Although not described in detail, the configuration of the terminal 42 on the side wall 50b facing the side wall 50a, the notch 43, the wiring 22, the partition plate 51, and the like is the same as that in FIG.

<Action>
The operation of the battery pack 1 of the present embodiment will be described in comparison with the battery pack according to the comparative example.

  FIG. 9 is a perspective view of the cover 150 used in the battery pack according to the comparative example, as viewed from the lower surface (the surface facing the circuit board 40). In FIG. 9, the same members as those shown in FIG. As can be easily understood by comparing FIG. 9 with FIG. 7 showing the cover 50 according to the embodiment of the present invention, the cover 150 of the comparative example includes a partition plate 51 and a partition plate formed on the cover 50. 52a and 52b are not formed. In the battery pack of the comparative example, the cover 150 is used instead of the cover 50 in the battery pack 1 of the present invention.

  FIG. 10 is an enlarged perspective view showing the terminals 42, the notches 43, the wirings 22 and the like as seen from the side wall 50a side of the battery pack according to the comparative example in the same manner as FIG. In FIG. 10, the same members as those shown in FIG. As can be easily understood by comparing FIG. 10 with FIG. 8, the partition plate 51 and the partition plate 52a shown in FIG. 8 do not exist in FIG. Except this, FIG. 10 is the same as FIG.

  As described above, vibration or impact may be applied to the battery pack during transportation or transportation of the battery pack. The battery stack 20 may move in the housing 30 due to such vibrations and shocks, which causes the wiring 22 to be displaced and tension to be applied to the wiring 22. As a result, the wiring 22 may break.

  FIG. 11 is a cutaway perspective view showing a state in which one wiring 22 is broken at the connection portion between the wiring 22 and the terminal 42 in the battery pack according to the comparative example shown in FIG. 10. As described above, the wiring 22 is bent and deformed and connected to the terminal 42. When the wiring 22 is broken, the wiring 22 that has been bent and deformed elastically recovers and contacts the adjacent wiring 22 as shown in FIG. When the voltage monitoring wirings 22 are short-circuited, the battery cell 10 abnormally generates heat, and in the worst case, smoke or fire occurs. Although not shown in the drawing, the shorted wiring 22 may come into contact with components mounted on the circuit board 40 or a wiring circuit formed on the circuit board 40. Abnormal heat generation of the cell 10 can occur.

  On the other hand, in the battery pack 1 of the present invention, as shown in FIG. 8, a part of the wiring 22 is accommodated in the space 55 defined by the partition plate 51. Therefore, as shown in FIG. 12, even if one wire 22 is broken, the broken wire 22 collides with the partition plate 51 and its displacement is limited, and the wire 22 protrudes beyond the space 55 corresponding to the wire 22. There is nothing. Therefore, there is a low possibility that the broken wiring 22 contacts the adjacent wiring 22, the terminal 42, etc., and a short circuit accident occurs. Further, since the partition plate 52a also restricts the displacement of the broken wiring 22, it is unlikely that the broken wiring 22 will come into contact with surrounding parts, wiring circuits, etc., causing a short circuit accident.

  As described above, in the battery pack 1 of the present invention, the partition plate 51 is formed on the surface of the cover 50 that faces the circuit board 40. A plurality of spaces (small rooms) 55 are formed in the cover 50 by the partition plate 51. The space 55 corresponds to the wiring 22 one to one. A part of one wiring 22 connected to the terminal 42 is accommodated in one space 55 corresponding to the wiring 22. Therefore, even if the wiring 22 breaks, the wiring 22 does not protrude beyond the partition 55 in the horizontal direction beyond the space 55. Therefore, it is possible to prevent the occurrence of a short circuit accident due to the breakage of the wiring 22.

  The circuit board 40 is formed with a plurality of cutouts 43 that respectively lock the plurality of wirings 22. The notch 43 functions as a position regulating mechanism that regulates the position of the wiring 22 in the horizontal direction (the direction parallel to the circuit board 40), and continues to regulate the position of the wiring 22 even if the wiring 22 is broken. Therefore, the position regulating mechanism is advantageous in reducing the possibility that the broken wiring 22 protrudes outside the corresponding space 55 in the horizontal direction.

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

  The configuration of the partition plate that defines the space 55 in which the wiring 22 is accommodated can be appropriately changed according to the arrangement of the wiring 22 and the terminal 42 on the circuit board 40. When viewed from above, the wiring 22, the terminal 42, and the space 55 do not need to be arranged in a straight line as in the above-described embodiment. For example, when the wiring 22 and the terminal 42 are arranged on a lattice point, the partition plate can be arranged in a lattice shape.

  In the above embodiment, the side walls 50a and 50b and the partition plates 52a and 52b of the cover 50 also contribute to defining the space 55. However, the side walls 50a and 50b and the partition plates 52a and 52b need to define the space 55. There is no. That is, in said embodiment, the partition plate 55 may be spaced apart from the side walls 50a and 50b. Further, the partition plates 52a and 52b may be omitted.

  The protruding height of the partition plate cover 50 from the top plate 53 is arbitrary. As long as the short circuit due to the broken wiring 22 can be prevented, the partition plate may be a rib-shaped projection having a low protrusion height from the top plate 53. In addition, when the partition plate does not collide with components mounted on the circuit board 40, the lower end of the partition plate may contact the circuit board 40.

  The configuration of the position restricting mechanism that restricts the position of the wiring 22 in the horizontal direction is not limited to the substantially L-shaped notch 43 described above. For example, a cutout having an arbitrary shape other than a substantially L shape may be used. Alternatively, instead of the cutout 43, a through hole that is not opened at the side end of the circuit board 40 may be used. The position in the horizontal direction of the plurality of wirings 22 may be restricted by one common position restriction mechanism. A notch or a through hole formed in the circuit board 40 for guiding the wiring 22 from the battery stack 20 side of the circuit board 40 to the opposite side is so large that the wiring 22 does not substantially have a position regulating function. You may have dimensions. The notch 43 for guiding the wiring 22 may be omitted by making the size of the circuit board 40 smaller than the opening size on the upper side of the housing 30.

  The structure of the battery laminated body with which the battery pack of this invention is provided is not limited to said embodiment. The number of battery cells 10 constituting the battery stack may be larger or smaller than in the above embodiment. Depending on the number of battery cells 10, the number of wirings 22, terminals 42, and spaces 55 is changed.

  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 10 Battery cell 20 Battery laminated body 22 Voltage monitoring wiring 40 Circuit board 42 Terminal 43 Notch (position control mechanism)
50 Cover 51 Partition plate 52a, 52b Screen 55

Claims (4)

A battery stack in which a plurality of thin battery cells are stacked and the plurality of battery cells are connected in series;
A circuit board provided with a plurality of terminals on the surface opposite to the battery laminate;
A plurality of voltage monitoring wirings derived from the battery stack and electrically connected to the plurality of terminals, respectively;
A battery pack comprising a cover that covers at least the plurality of terminals and the plurality of wires,
A partition plate is erected on the cover,
A plurality of spaces are defined by the partition plate,
A part of each of the plurality of wirings connected to the plurality of terminals is housed in each of the plurality of spaces. The plurality of terminals are arranged in a straight line;
The battery pack according to claim 1, wherein a plurality of the partition plates are spaced apart from each other along a direction parallel to the straight line.   The battery pack according to claim 2, wherein a partition plate that connects the plurality of partition plates and is parallel to the straight line is erected on the cover.   The battery pack according to claim 1, wherein a position regulation mechanism that regulates a position of the wiring in a direction parallel to the circuit board is formed on the circuit board.

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