Battery pack

Abstract

To provide a battery pack capable of simplifying a layout structure.SOLUTION: A battery pack 100 comprises: a plurality of cylindrical-shaped batteries 120 each of which has an electrode 121 on both end surfaces in an axial direction Z, being arranged so that their outer peripheral surfaces 120a are opposed to each other; a plurality of bus bars 2 fixed to the electrodes; and a flexible printed wiring board 3 that has a plurality of conductors connected with the plurality of bus bars. The flexible printed wiring board has: a belt-like main body 31 arranged along the outer peripheral surfaces of the plurality of batteries; and branch parts 32 protruded from the main body and connected with the bus bars.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Conventionally, there are battery packs that have cylindrical batteries. Patent Document 1 discloses a battery pack in which a battery module has multiple cylindrical batteries and a battery holder made of a heat conductive material. In the battery pack of Patent Document 1, a positive bus bar that connects the upper electrodes (positive electrodes) of the cylindrical batteries is attached to the upper side of the hole in the cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-178069 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to be able to simplify the wiring structure in a battery pack having cylindrical batteries. For example, in a configuration in which a bus bar is fixed to an electrode, it is desirable to be able to wire a voltage detection line while suppressing interference with the bus bar.

[0005] An object of the present invention is to provide a battery pack that can simplify the wiring structure. [Means for solving the problem]

[0006] The battery pack of the present invention comprises a plurality of batteries which are cylindrical in shape and have electrodes on both axial end surfaces and are arranged with their outer peripheral surfaces facing each other, a plurality of bus bars fixed to the electrodes, and a flexible printed wiring board having a plurality of conductors connected to the bus bars, wherein the flexible printed wiring board has a band-shaped main body arranged along the outer peripheral surfaces of the plurality of batteries, and branch portions protruding from the main body and connected to the bus bars. Effect of the Invention

[0007] The flexible printed wiring board of the battery pack according to the present invention has a belt-shaped main body that is routed along the outer peripheral surfaces of the multiple batteries, and branch portions that protrude from the main body and are connected to the bus bars. The battery pack according to the present invention has an advantage that the routing structure can be simplified by routing the belt-shaped main body along the outer peripheral surfaces of the batteries. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a battery pack according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of the substrate module according to the embodiment. [Diagram 3] FIG. 3 is a plan view of the flexible printed wiring board according to the embodiment. [Figure 4] FIG. 4 is a perspective view of a holding member according to the embodiment. [Diagram 5] FIG. 5 is a perspective view showing a process of assembling the board module to the battery module. [Figure 6] FIG. 6 is a plan view of the battery pack according to the embodiment. [Figure 7] FIG. 7 is a perspective view of the battery pack according to the embodiment. [Figure 8] FIG. 8 is a plan view of the battery pack according to the embodiment. [Figure 9] FIG. 9 is a plan view of the bus bar module according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a battery pack according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment. In addition, the components in the following embodiment include those that can be easily imagined by a person skilled in the art or those that are substantially the same.

[0010] [Embodiment] An embodiment will be described with reference to Fig. 1 to Fig. 9. The embodiment relates to a battery pack. Fig. 1 is a perspective view of a battery pack according to an embodiment, Fig. 2 is a perspective view of a board module according to an embodiment, Fig. 3 is a plan view of a flexible printed wiring board according to an embodiment, Fig. 4 is a perspective view of a holding member according to an embodiment, Fig. 5 is a perspective view showing a process of assembling the board module to a battery module, Fig. 6 is a plan view of the battery pack according to an embodiment, Fig. 7 is a perspective view of the battery pack according to an embodiment, Fig. 8 is a plan view of the battery pack according to an embodiment, and Fig. 9 is a plan view of a busbar module according to an embodiment.

[0011] 1, the battery pack 100 of this embodiment has a battery module 110, a plurality of bus bars 2, and a board module 1. The battery pack 100 is mounted as a power source in vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The battery pack 100 may have a plurality of battery modules 110 and a plurality of board modules 1.

[0012] The battery module 110 has a plurality of batteries 120. The plurality of batteries 120 are housed in a housing. The batteries 120 are single cells that can be charged and discharged. The shape of the battery 120 in this embodiment is cylindrical or columnar. The battery 120 has electrodes 121 on both end surfaces in the axial direction Z. One of the two electrodes 121 is a positive electrode, and the other is a negative electrode.

[0013] The battery module 110 has multiple battery columns 120q. One battery column 120q has multiple batteries 120 arranged in a straight line along a first direction X. The multiple battery columns 120q are arranged along a second direction Y. The second direction Y is perpendicular to the first direction X and perpendicular to the axial direction Z of the batteries 120. The multiple batteries 120 are arranged with the outer circumferential surfaces 120a of the batteries 120 facing each other.

[0014] Two adjacent battery rows 120q are arranged to be offset in the first direction X. The multiple battery rows 120q are arranged, for example, such that the batteries 120 form a honeycomb structure. Three adjacent batteries 120 form a space 130 in the shape of a triangular prism.

[0015] The bus bar 2 is formed from a conductive metal plate such as copper or aluminum. The bus bar 2 has, for example, a flat plate shape. The illustrated bus bar 2 is connected to electrodes 121 of a plurality of batteries 120. The bus bar 2 is connected to, for example, the positive electrode of the battery 120. The bus bar 2 of this embodiment connects the plurality of batteries 120 in parallel.

[0016] The board module 1 has a plurality of conductors, and connects the plurality of bus bars 2 to an external device. The external device is typically a monitoring device that monitors the battery pack 100. The board module 1 may be provided with a connector that is connected to the external device. The board module 1 has a flexible printed wiring board 3 and a holding member 4.

[0017] The flexible printed wiring board 3 is a printed circuit board having flexibility. The flexible printed wiring board 3 has a resin layer formed of an insulating synthetic resin and a plurality of conductors. The conductor is a conductor layer sandwiched between two resin layers, and is, for example, a metal foil such as a copper foil. As shown in Fig. 2 and Fig. 3, the flexible printed wiring board 3 has a main body 31 and branch portions 32. The main body 31 and the branch portions 32 are, for example, integral with each other.

[0018] As shown in Fig. 3, the main body 31 is belt-shaped. The shape of the main body 31 in a plan view is rectangular. The branch portion 32 protrudes from one side 31a along the longitudinal direction of the main body 31. The branch portion 32 is connected to the corresponding bus bar 2. The conductor 5 is wired to the main body 31 and the branch portion 32. The branch portion 32 and the conductor 5 are flexible and can be bent relative to the main body 31. The conductor 5 is a voltage detection line that detects the voltage of the battery 120. One end of the conductor 5 is connected to the bus bar 2, and the other end of the conductor 5 is connected to an external device.

[0019] The holding member 4 is a member that holds the main body 31 of the flexible printed wiring board 3. The holding member 4 is molded, for example, from an insulating synthetic resin. The holding member 4 may be made of an elastically deformable material such as rubber. As shown in FIG. 4, the holding member 4 has a columnar shape. The holding member 4 is formed so as to be insertable into a triangular columnar space 130 formed by the battery 120. The holding member 4 has three opposing surfaces 41, three side surfaces 42, a top surface 43, and a bottom surface 44. The top surface 43 and the bottom surface 44 are end surfaces of the holding member 4 in the axial direction. The opposing surfaces 41 and the side surfaces 42 extend along the axial direction of the holding member 4 from the top surface 43 to the bottom surface 44.

[0020] The opposing surface 41 is a surface that faces the outer peripheral surface 120a of the battery 120. The cross-sectional shape of the opposing surface 41 is an arc shape that curves toward the central axis CL of the holding member 4. The side surface 42 is a plane that connects one opposing surface 41 to another opposing surface 41.

[0021] The holding member 4 has a slit-shaped recess 45 into which the main body 31 of the flexible printed wiring board 3 is inserted. When viewed from the direction of the central axis CL, the shape of the recess 45 is an arc shape curved toward the central axis CL. The recess 45 extends along the central axis CL from the top surface 43 to the vicinity of the bottom surface 44. The recess 45 opens to each of the two side surfaces 42. The depth of the recess 45 in the axial direction is equal to the width of the main body 31 of the flexible printed wiring board 3. The main body 31 of the flexible printed wiring board 3 is inserted into the recess 45 from the side opposite to the side 31a having the branch portion 32.

[0022] As shown in Fig. 5, the board module 1 is inserted into the battery module 110 along the axial direction Z. The bus bar 2 is fixed to the batteries 120 of the battery module 110 in advance. The bus bar 2 is fixed to the electrodes 121 of the batteries 120 by welding or the like. The main body 31 of the flexible printed wiring board 3 is inserted between two adjacent battery rows 120q. At this time, the holding member 4 is inserted into a triangular prism-shaped space 130 formed by the three batteries 120.

[0023] FIG. 6 shows the board module 1 inserted between two battery strings 120q. The main body 31 of the flexible printed wiring board 3 is arranged in a wave-like curved shape with both sides of the main body 31 facing the outer peripheral surface 120a of the multiple batteries 120. The holding member 4 inserted into the space 130 can determine the curved shape of the main body 31. As shown in FIG. 6, the holding members 4 are arranged on both sides of the branch portion 32. The two holding members 4 can hold the main body 31 so that the main body 31 extends linearly between the two holding members 4. The holding member 4 is configured to provide a gap between both sides of the main body 31 and the outer peripheral surface 120a of the batteries 120, for example.

[0024] The holding member 4 determines the orientation of the branch portion 32 and can position the branch portion 32 with respect to the bus bar 2. The conductor 5 of the branch portion 32 is connected to the bus bar 2 by welding, soldering, or the like. A connector for connecting to an external device may be provided at an end of the main body 31.

[0025] When the board module 1 is assembled to the battery module 110, resin is injected into the housing of the battery module 110. The injected resin solidifies to fix the battery 120 and the board module 1. The injected resin may be an insulating synthetic resin. The injected resin may also function as a heat transfer member that dissipates heat generated by the battery 120.

[0026] In the battery pack 100 of this embodiment, the main body 31 of the flexible printed wiring board 3 is routed along the outer peripheral surface 120a of the multiple batteries 120. Therefore, the main body 31 can have a sufficient width for the multiple conductors 5. As a comparative example, a configuration in which the main body of the flexible printed wiring board is routed along the end face of the battery 120 will be considered. In this case, it is necessary to narrow the width of the main body of the flexible printed wiring board so as not to interfere with the bus bar 2. As a result, measures such as overlapping and routing multiple flexible printed wiring boards are required.

[0027] In contrast, in the battery pack 100 of this embodiment, restrictions on the maximum width of the main body 31 are relaxed, and the configuration structure is simplified. A plurality of conductors 5 can be arranged in one main body 31, thereby realizing cost reduction. Since the width of the main body 31 can be sufficiently secured, problems with circuit resistance are unlikely to occur. In addition, since the main body 31 is arranged in the space between the battery strings 120q, the battery pack 100 can be made low-profile. Note that in the main body 31 of the flexible printed wiring board 3, the conductors 5 may be arranged in two layers.

[0028] The main body 31 may be disposed on the outside of the battery string 120q as shown in Figs. 7 and 8. Fig. 8 shows a housing 150 that houses a plurality of batteries 120. The main body 31 is routed in a gap between an inner wall surface 150a of the housing 150 and the battery string 120q disposed at the end. In this case, the main body 31 can be routed linearly along the inner wall surface 150a. The main body 31 may be held by being sandwiched between the battery string 120q and the inner wall surface 150a.

[0029] As described above, the battery pack 100 of this embodiment has a plurality of cylindrical batteries 120, a plurality of bus bars 2, and a flexible printed wiring board 3. The plurality of batteries 120 have electrodes 121 on both end surfaces in the axial direction Z, and are arranged with their outer circumferential surfaces 120a facing each other. The plurality of bus bars 2 are fixed to the electrodes 121. The flexible printed wiring board 3 has a plurality of conductors 5 connected to the plurality of bus bars 2.

[0030] The flexible printed wiring board 3 has a belt-shaped main body 31 and branch portions 32 protruding from the main body 31. The main body 31 is routed along the outer peripheral surface 120a of the multiple batteries 120. The branch portions 32 are connected to the bus bar 2. In the battery pack 100 of this embodiment, the belt-shaped main body 31 is routed along the outer peripheral surface 120a of the batteries 120. It becomes easy to arrange the required number of conductors 5 on one body 31, and the routing structure of the battery pack 100 is simplified. It becomes possible to omit a case for holding the main body 31, and the configuration of the battery pack 100 is simplified, and the battery pack 100 is made low-profile.

[0031] The main body 31 of this embodiment is arranged in a wavy curved shape with both sides of the main body 31 facing the outer peripheral surfaces 120a of the multiple batteries 120. By arranging the main body 31 using the gaps provided between adjacent battery rows 120q, it is possible to reduce the size and height of the battery pack 100.

[0032] The battery pack 100 of this embodiment has a columnar holding member 4 that holds the main body 31 of the flexible printed wiring board 3. The holding member 4 has a slit-like recess 45 into which the main body 31 is inserted. The holding member 4 is housed in a triangular column-shaped space 130 formed by three adjacent batteries 120 to hold the main body 31. The holding member 4 can stabilize the routing shape of the main body 31.

[0033] The procedure for assembling the busbar 2 and the board module 1 to the battery module 110 is not limited to the above procedure. For example, as shown in Fig. 9, the busbar module 10 may be configured by attaching the busbar 2 to the board module 1. The busbar module 10 is assembled to the battery module 110. The main body 31 of the flexible printed wiring board 3 is routed along the outer peripheral surface 120a of the battery 120. Therefore, when the busbar 2 is welded to the electrode 121 of the battery 120, the main body 31 does not get in the way of the welding operation.

[0034] The board module 1 does not necessarily have to have the holding member 4. When the main body 31 of the flexible printed wiring board 3 is inserted into the gaps between the battery rows 120q, a jig may be used for the insertion operation.

[0035] The number of batteries 120 connected to one bus bar 2 is arbitrary. The flexible printed wiring board 3 may have a conductor 5 different from the voltage detection line. For example, the multiple conductors 5 may include a temperature detection line for detecting temperature. The temperature detection line may be connected to a thermistor.

[0036] The contents disclosed in the above embodiments can be implemented in appropriate combinations. [Explanation of symbols]

[0037] 1 PCB Module 2: bus bar; 3: flexible printed wiring board; 4: holding member 10 Busbar module 31: main body, 31a: one side, 32: branch 41: Opposing surface, 42: Side surface, 43: Top surface, 44: Bottom surface, 45: Recessed part 100 Battery Packs 110 Battery module 120: Battery, 120a: Outer surface, 120q: Battery row, 121: Electrode 130: Space, 150: Housing X: First direction, Y: Second direction, Z: Axial direction

Claims

[Claim 1] A plurality of batteries each having a cylindrical shape, electrodes on both axial end surfaces, and arranged with their outer circumferential surfaces facing each other; A plurality of bus bars fixed to the electrodes; a flexible printed wiring board having a plurality of conductors connected to a plurality of the bus bars; A columnar holding member, the flexible printed wiring board has a belt-shaped main body that is arranged along the outer circumferential surfaces of the plurality of batteries, and a branch portion that protrudes from the main body and is connected to the bus bar, the main body is arranged in a wavy curved shape with both surfaces of the main body facing the outer peripheral surfaces of the plurality of batteries, The holding member is a member for holding the main body, has a slit-shaped recess into which the main body is inserted, and is accommodated in a triangular prism-shaped space formed by three adjacent batteries to hold the main body. A battery pack characterized by:

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