Busbar Module

Abstract

To provide a bus bar module excellent in an assembly performance to a battery collector and deformation of the battery collector, or a followability of a manufacturing variation.SOLUTION: A bus bar module 10 attached to a battery collector 1 to which a plurality of cell batteries 2 is laminated, comprises: a main line circuit body 20 that is constructed by a flexible substrate having a first wiring pattern 26, and is extended along a lamination direction of the plurality of cell batteries 2; a branch circuit body 30 that is constructed by the flexible substrate having second wiring patterns 37 and 38, in which the second wiring pattern 37 is electrically connected to the first wiring pattern 26, and which is extended so as to be branched from main line circuit body 20; a bus bar 40 connected to each of electrodes 4 and 5 of the plurality of cell batteries 2; an electronic component 50 that is attached to a mounting surface provided to the branch circuit body 30 so as to connect the second wiring pattern 38 and the bus bar 40; and a holder 60 that can be extended and compressed along the lamination direction while holding the bus bar 40.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a bus bar module. [Background technology]

[0002] Conventionally, busbar modules have been used by being assembled into battery assemblies (battery modules in which multiple battery cells are stacked) as driving power sources mounted on electric vehicles, hybrid vehicles, and the like (see, for example, Patent Document 1).

[0003] The busbar module described in Patent Document 1 includes multiple busbars that are stacked to connect the positive and negative electrodes of adjacent battery cells, and voltage detection wires that are connected to each of the multiple busbars to monitor each battery cell. The voltage detection wires are configured to bundle multiple electric wires that have a general structure in which core wires are covered with an insulating coating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-220128 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the battery cells constituting a battery assembly expand and contract in the stacking direction due to operating heat generated during charging and discharging, the temperature of the external environment, and the like. As a result, the battery assembly (battery module) also deforms by expanding and contracting in the stacking direction of the battery cells. Furthermore, due to assembly tolerances when stacking multiple battery cells, the size of the battery assembly in the stacking direction generally varies for each manufactured battery assembly (manufacturing variations may occur). Therefore, busbar modules are generally designed to provide a certain amount of leeway in the length of the voltage detection wires to accommodate such deformation of the battery assembly and manufacturing variations.

[0006] However, in the conventional busbar module described above, for example, when the number of stacked battery cells is increased for the purpose of increasing the capacity of the battery assembly, the number of wires constituting the voltage detection line also increases. As a result, when the voltage detection line is formed by bundling these many wires, the rigidity of the voltage detection line as a whole (and thus the rigidity of the busbar module) increases, which may make it difficult to improve the workability (assembly) of assembling the busbar module to the battery assembly. For the same reason, it may also become difficult for the busbar module to expand and contract so as to adequately accommodate deformation and manufacturing variations in the battery assembly.

[0007] An object of the present invention is to provide a bus bar module that is easy to install into a battery assembly and has excellent adaptability to deformation of the battery assembly and manufacturing variations. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a bus bar module according to the present invention has the following features.

[0009] A busbar module that is attached to a battery assembly in which a plurality of unit cells are stacked, A main line circuit body that is made of a flexible substrate having a first wiring pattern and is arranged to extend along the stacking direction of the plurality of unit cells; a branch circuit body that is formed of a flexible substrate having a second wiring pattern, the second wiring pattern being electrically connected to the first wiring pattern and extending so as to branch off from the main circuit body; A bus bar to be connected to each electrode of the plurality of single cells; an electronic component attached to a mounting surface of the branch circuit body so as to connect the second wiring pattern and the bus bar; a holder that holds the bus bar and is extendable and contractible along the stacking direction. 、 a pair of first openings, through which the first wiring pattern is exposed, are provided in a connection portion of the main line circuit body for connecting the branch line circuit body to the main line circuit body, the first openings being arranged side by side with a gap therebetween in the stacking direction; a circuit body side connection portion, which is a portion of the branch circuit body connected to the connection portion of the main circuit body, has a pair of second openings, through which the second wiring pattern is exposed, and the second openings are arranged side by side with a gap in between in the stacking direction, the second openings corresponding to the pair of first openings; the first wiring pattern exposed from the pair of first openings and the second wiring pattern exposed from the pair of second openings are soldered together, so that the first wiring pattern and the second wiring pattern are electrically connected to each other. It is a busbar module. Effect of the Invention

[0010] According to the busbar module of the present invention, a branch circuit body (hereinafter also referred to as a branch line) made of a flexible substrate is electrically connected to a main circuit body (hereinafter also referred to as a trunk line) made of a flexible substrate, and the branch circuit body extends so as to branch off from the main circuit body. Therefore, when the battery assembly expands or contracts in the stacking direction due to thermal deformation of each unit cell, the branch circuit body is bent or the like, so that each busbar can move in the stacking direction of the unit cells. Similarly, the branch circuit body is bent or the like, so that the variation in size in the stacking direction of the battery assembly caused by the assembly tolerance of the unit cells can be absorbed. In other words, the busbar module of this configuration can easily accommodate the expansion and contraction of the battery assembly and the manufacturing variation by deforming the branch circuit body. Here, a flexible substrate is generally more easily deformed with a much smaller force than the electric wire used in the conventional busbar module described above, even when it contains a large number of circuit structures. Therefore, the ease of assembly to the battery assembly is improved. Therefore, the bus bar module of this configuration is superior in ease of assembly into a battery assembly and in adaptability to deformations and manufacturing variations in the battery assembly, compared to the conventional bus bar module described above.

[0011] Furthermore, according to the busbar module having the above configuration, the main line circuit body and the branch line circuit body are prepared as separate bodies and then electrically connected to each other. Therefore, compared to the case where the main line circuit body and the branch line circuit body are configured as an integral, continuous flexible board, it is not necessary to process the flexible board into a shape in which the branch line circuit body branches off from the main line circuit body (for example, punching out an original plate of the flexible board and processing it into a shape in which the branch line circuit body branches off from the main line circuit body). Therefore, it is possible to reduce the amount of scrap pieces discarded due to such processing, and to improve productivity (i.e., yield). In particular, it is possible to improve productivity in that it is not necessary to discard the original plate located between the adjacent branch line circuits in the stacking direction. In addition, since electronic components are attached (i.e., mounted) to the branch line circuit body prepared as a separate body from the main line circuit body, compared to the case where the main line circuit body and the branch line circuit body are configured as an integral flexible board, a large mounting device is not required for mounting electronic components. In other words, regardless of the length or size of the main line circuit body, electronic components can be properly mounted on the branch line circuit body using a general mounting device, thereby reducing the manufacturing costs of the busbar module.

[0012] The present invention has been briefly described above. The details of the present invention will become clearer by reading the detailed description of the invention described below with reference to the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a bus bar module according to the present embodiment. [Diagram 2] FIG. 2 is a perspective view showing a battery assembly to which the bus bar module shown in FIG. 1 is assembled. [Diagram 3] FIG. 3 is a perspective view showing a state in which bus bars are connected to each of a plurality of branch line circuits connected to a main line circuit body. [Figure 4] FIG. 4 is a perspective view showing one branch line circuit body connected to a main line circuit body. [Diagram 5]FIG. 5 is a perspective view showing a state in which a bus bar is connected to one branch line circuit body that is connected to a main line circuit body. [Figure 6] FIG. 6 is a perspective view showing the holder and the cover shown in FIG. [Figure 7] FIG. 7 is a top view showing a connection portion between the branch circuit body and the bus bar. [Figure 8] FIG. 8 is a perspective view for explaining an operation for connecting a branch line circuit body to a main line circuit body using a jig. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Embodiment> Hereinafter, a busbar module 10 according to an embodiment of the present invention will be described with reference to the drawings. The busbar module 10 according to the present embodiment is used, for example, by being assembled to a long battery assembly 1 (see FIG. 2; a battery module in which a plurality of unit cells are stacked) as a driving power source mounted on an electric vehicle.

[0015] For ease of explanation, "front," "rear," "left," "right," "top," and "bottom" are defined below as shown in FIG. 1 etc. The "front-rear direction," "left-right direction," and "up-down direction" are perpendicular to each other. The front-rear direction coincides with the stacking direction of the multiple single cells 2 that make up the battery assembly 1 (see FIG. 1 and FIG. 2). Note that these directions are defined for ease of explanation, and do not necessarily correspond to the front-rear direction, left-right direction, and up-down direction of the vehicle when the busbar module 10 is mounted on the vehicle.

[0016] First, in preparation for explaining the busbar module 10, a battery assembly 1 to which the busbar module 10 is attached will be described with reference to Fig. 2. As shown in Fig. 2, the battery assembly 1 is formed by stacking a plurality of rectangular flat-plate-shaped unit cells 2 extending in the up-down and left-right directions in the front-rear direction. Each of the plurality of unit cells 2 is formed of a rectangular flat-plate-shaped battery body 3 and a positive electrode 4 and a negative electrode 5 protruding upward from both left-right ends of an upper surface 6 of the battery body 3.

[0017] In the battery assembly 1, the left-right positions of the positive electrodes 4 and negative electrodes 5 of adjacent single cells 2 in the front-to-rear direction are reversed, so that the positive electrodes 4 and negative electrodes 5 are alternately arranged in the front-to-rear direction at each of the left and right ends of the upper surface of the battery assembly 1.

[0018] The busbar module 10 will be described below. As shown in Figs. 1, 3, 6, etc., the busbar module 10 includes a main line circuit body 20 (see Fig. 3) extending in the front-rear direction, a plurality of branch line circuit bodies 30 connected to the main line circuit body 20, a plurality of bus bars 40 connected to the plurality of branch line circuit bodies 30, a plurality of electronic components 50 mounted on the plurality of branch line circuit bodies 30, a holder 60 that holds the main line circuit body 20, the branch line circuit body 30, and the bus bar 40, and a cover 70 that covers the main line circuit body 20 and the branch line circuit body 30. The main line circuit body 20 is also called a trunk line, and the branch line circuit body 30 is also called a branch line. Each member constituting the busbar module 10 will be described below in order.

[0019] First, the main line circuit body 20 will be described. The main line circuit body 20 is made of an easily bendable flexible printed circuit (FPC), and as shown in Fig. 3, is integrally provided with a pair of left and right band-shaped main body parts 21 extending in the front-rear direction with a gap in the left-right direction, and a connecting part 22 (see also Fig. 1) that connects the pair of main body parts 21 in the left-right direction at approximately the center position in the front-rear direction of the pair of main body parts 21. A connector 27 that is electrically connected to an external voltage detection device (not shown) or the like is mounted on the lower surface of the connecting part 22.

[0020] The entire surface of the main circuit body 20 is made of a resin layer except for an opening 25 (see FIG. 8) described later, and contains a wiring pattern 26 (see FIG. 8) described later. The wiring pattern 26 is typically a copper conductor pattern extending in a strip shape.

[0021] Connection parts 23 for connecting branch circuit bodies 30 are arranged at multiple locations on the outer left and right ends of each of the pair of left and right main body parts 21 in the front-rear direction (see Figs. 3 to 5 and 8). As shown in Fig. 8, each connection part 23 is provided with a pair of through holes 24 penetrating in the thickness direction (up-down direction) and aligned with a gap in the front-rear direction. The effect of providing the pair of through holes 24 will be described later.

[0022] Further, as shown in FIG. 8, a pair of openings 25, in which the resin layer on the surface is removed to expose the wiring pattern 26, are provided on the lower surface of each connection portion 23 at positions different from the pair of through holes 24, so as to be aligned at an interval in the front-rear direction. When the branch circuit body 30 is connected to the main line circuit body 20, the wiring pattern 26 exposed in the pair of openings 25 and a wiring pattern 37 (see FIG. 8) exposed from a pair of openings 31b of the branch circuit body 30, which will be described later, are electrically connected (soldered in this example). The wiring patterns 26 exposed in the openings 25 of each connection portion 23 are individually passed through the insides of the main body portion 21 and the coupling portion 22 in this order, and are electrically connected to the connector 27 mounted on the coupling portion 22. As a result, the wiring patterns 26 located at each connection portion 23 are individually conductively connected to an external voltage detection device via the connector 27 mounted on the coupling portion 22.

[0023] Next, the branch line circuit body 30 will be described. The branch line circuit body 30 is made of an easily bendable flexible printed circuit (FPC) like the main line circuit body 20. As shown in Fig. 3 etc., the branch line circuit body 30 is connected to the main line circuit body 20 so as to branch out outward in the left and right direction from each of the connection parts 23 provided on each of the pair of left and right body parts 21 of the main line circuit body 20.

[0024] As shown in FIG. 8, the branch circuit body 30 integrally includes a circuit body side connection portion 31 extending in the front-rear direction, a first portion 32 extending outward in the left-right direction from a predetermined position in the front-rear direction of the circuit body side connection portion 31, a second portion 33 extending forward in a strip shape from an extending end portion of the first portion 32, a third portion 34 extending outward in the left-right direction from an extending end portion of the second portion 33, a fourth portion 35 extending rearward in a strip shape from an extending end portion of the third portion 34, and a busbar side connection portion 36 provided at an extending end portion of the fourth portion 35. The branch circuit body 30 has such a U-shaped curved shape, which enhances the flexibility of the branch circuit body 30 in the front-rear, left-right, and up-down directions (see the white arrow in FIG. 5). Note that a branch circuit body 30 having an overall shape obtained by turning the overall shape of the branch circuit body 30 shown in FIG. 8 in the front-rear direction inverted is connected to some of the multiple connection portions 23 of the main circuit body 20. For the sake of convenience, the following description will be given assuming that the branch circuit body 30 has the overall shape shown in FIG.

[0025] Like the main line circuit body 20, the entire surface of the branch line circuit body 30 is made of a resin layer except for openings 31b, 36a, and 36b (see FIG. 8) described below, and contains wiring patterns 37 and 38 (see FIGS. 7 and 8) described below. The wiring patterns 37 and 38 are typically copper conductor patterns extending in a strip shape.

[0026] The circuit body side connection portion 31 is a portion that is connected to the connection portion 23 (wiring pattern 26) of the main line circuit body 20. In the circuit body side connection portion 31, a pair of through holes 31a that penetrate in the thickness direction (vertical direction) corresponding to the pair of through holes 24 of the connection portion 23 of the main line circuit body 20 are provided so as to be aligned at a distance in the front-rear direction (see FIG. 8). Furthermore, on the upper surface of the circuit body side connection portion 31, a pair of openings 31b, in which the resin layer on the surface is removed to expose the wiring pattern 37, are provided at positions different from the pair of through holes 31a so as to be aligned at a distance in the front-rear direction (see FIG. 8) corresponding to the pair of openings 25 of the connection portion 23 of the main line circuit body 20. The wiring pattern 37 exposed in a pair of openings 31b extends through the first portion 32, the second portion 33, the third portion 34, the fourth portion 35 and the inside of the bus bar side connection portion 36 in that order, to an opening 36a provided in the bus bar side connection portion 36 (see Figures 7 and 8).

[0027] The busbar side connection portion 36 is a portion to which the busbar 40 is connected (see FIG. 5, etc.). As shown in FIGS. 7 and 8, an opening 36a is provided in the left-right center of the upper surface of the busbar side connection portion 36, where the resin layer on the surface has been removed, and openings 36b are formed in a pair of left and right positions on either side of the opening 36a, where the resin layer on the surface has been removed. An end of the wiring pattern 37 is exposed in the front region of the opening 36a, and a part of the wiring pattern 38 that is spaced apart from the wiring pattern 37 and is contained in the busbar side connection portion 36 is exposed in the rear region of the opening 36a. The other part of the wiring pattern 38 is exposed in each of the pair of openings 36b.

[0028] When the bus bar 40 is connected to the branch circuit body 30, the wiring pattern 38 exposed in the pair of openings 36b and an extension portion 42 (see Figures 3, 5 and 7) of the bus bar 40, which will be described later, are electrically connected (soldered in this example).

[0029] An electronic component 50 is mounted in the opening 36a of the branch circuit body 30 (see FIG. 8, etc.). The electronic component 50 is typically a chip fuse. The electronic component 50 is soldered to the wiring patterns 38 and 37 using solder H (see FIG. 7) so as to straddle the wiring patterns 38 and 37 exposed in the opening 36a. This electrically connects the wiring pattern 38 (i.e., the bus bar 40) and the wiring pattern 37 (i.e., the wiring pattern 26 of the main circuit body 20) via the electronic component 50.

[0030] Such mounting of electronic components 50 on the branch circuit body 30 is performed before the branch circuit body 30 is connected to the long main circuit body 20 that is long in the front-rear direction (when the branch circuit body 30 is alone). Therefore, compared to a case in which the main circuit body 20 and the branch circuit body 30 are configured from a common flexible substrate, a large mounting device is not required. In other words, since the main circuit body 20 and the branch circuit body 30 are separate bodies, the electronic components 50 can be properly mounted on the branch circuit body 30 regardless of the length or size of the main circuit body 20, and the manufacturing cost of the busbar module 10 can be reduced.

[0031] Furthermore, since the main line circuit body 20 and the branch line circuit body 30 are separate bodies, it is not necessary to process the flexible board into a shape in which the branch line circuit body 30 branches off from the main line circuit body 20 (for example, by punching out an original plate of the flexible board and processing it into a shape in which the branch line circuit body 30 branches off from the main line circuit body 20), as compared to a case in which the main line circuit body 20 and the branch line circuit body 30 are configured from a common flexible board. This makes it possible to reduce the amount of scrap pieces discarded due to such processing, and improve productivity (i.e., yield). In particular, productivity can be improved in that the original plate portion sandwiched between adjacent branch line circuits 30 in the stacking direction is not discarded.

[0032] The operation of connecting the branch line circuit body 30 to the main line circuit body 20 is performed using a rod-shaped positioning jig 80, as shown in Fig. 8. That is, as shown in Fig. 8, first, the circuit body side connection portions 31 of the branch line circuit body 30 are positioned below the corresponding connection portions 23 of the main line circuit body 20, and then a pair of rod-shaped jigs 80 are inserted from below into the pair of through holes 31a of the branch line circuit body 30 and the pair of through holes 24 of the main line circuit body 20. This results in a state in which the pair of through holes 31a of the branch line circuit body 30 and the pair of through holes 24 of the main line circuit body 20 are aligned so as to overlap each other in the vertical direction.

[0033] Next, the wiring pattern 26 exposed from the pair of openings 25 of the main line circuit body 20 and the wiring pattern 37 exposed from the pair of openings 31b of the branch line circuit body 30 are soldered. This soldering can be typically performed by a method (so-called pulse heat method) in which paste-like solder is sandwiched between the wiring pattern 26 and the wiring pattern 37, and then a heater chip capable of heating the solder to a temperature at which the solder can be melted is pressed against the soldering location and the heater chip is heated to perform soldering. The soldering can also be performed by a reflow method using a heating furnace. Furthermore, the electrical connection between the wiring pattern 26 of the main line circuit body 20 and the wiring pattern 37 of the branch line circuit body 30 may be performed using a conductive adhesive instead of the above-mentioned soldering.

[0034] As a result, the branch circuit body 30 is connected to the main circuit body 20 with the wiring pattern 26 of the main circuit body 20 and the wiring pattern 37 of the branch circuit body 30 being electrically connected. In this manner, by using the through hole 31a of the branch circuit body 30 and the through hole 24 of the main circuit body 20, and the rod-shaped jig 80, it is possible to suppress misalignment and the like when soldering the wiring pattern 26 and the wiring pattern 37. This improves the reliability of the electrical connection between the main circuit body 20 and the branch circuit body 30.

[0035] Next, the bus bar 40 will be described. The bus bar 40 is formed by performing a press process (punching process), a bending process, and the like on a single metal plate. As shown in Fig. 3, the bus bar 40 includes a bus bar body 41 having a substantially rectangular flat plate shape, and an extension portion 42 extending inward in the left-right direction from a rear end of a left-right inner edge portion extending in the front-rear direction of the bus bar body 41. A through hole 43 (see Figs. 5 and 7) opening in the thickness direction (up-down direction) is formed at the extension end of the extension portion 42. The through hole 43 functions as a relief portion for avoiding interference between the extension end of the extension portion 42 of the bus bar 40 and the electronic component 50 when the bus bar 40 is connected to the branch circuit body 30.

[0036] Next, the holder 60 will be described. The holder 60 is a resin molded product, and as shown in Fig. 6, is integrally provided with a pair of left and right band-shaped circuit body holding portions 61 extending in the front-rear direction with a gap in the left-right direction, and a plurality of connecting portions 62 connecting the pair of left and right circuit body holding portions 61 in the left-right direction at multiple points in the front-rear direction. The pair of left and right body portions 21 of the main line circuit body 20 and the plurality of branch line circuit bodies 30 branching off from the body portion 21 are placed on the pair of left and right circuit body holding portions 61.

[0037] Each of the pair of circuit body holding parts 61 extending in the front-rear direction is specifically composed of a plurality of divided bodies 61a arranged in a line in the front-rear direction, and an expandable part 63 that connects adjacent divided bodies 61a in the front-rear direction in the front-rear direction. Each expandable part 63 has a shape that can easily expand and contract in the front-rear direction by elastic deformation. Therefore, the pair of circuit body holding parts 61 are configured to be expandable and contractable along the front-rear direction.

[0038] For each of the pair of left and right circuit body holding portions 61, a bus bar holding portion 64 is integrally provided adjacent to the outer side in the left-right direction on each of the multiple divided bodies 61a aligned in the front-rear direction. That is, the multiple bus bar holding portions 64 are arranged aligned in the front-rear direction on the outer side in the left-right direction of each of the pair of left and right circuit body holding portions 61. Since each bus bar holding portion 64 is provided on the corresponding divided body 61a, the front-rear distance between adjacent bus bar holding portions 64 in the front-rear direction can be changed by the function of the expansion and contraction portion 63.

[0039] The busbar holding portion 64 accommodates the busbar body 41 of the busbar 40. Therefore, the busbar holding portion 64 has a substantially rectangular box shape that opens upward in correspondence with the outer shape of the busbar body 41. A notch 65 is formed in a portion of the rectangular frame-shaped side wall portion of the busbar holding portion 64 where the extension portion 42 of the busbar 40 crosses in order to avoid interference with the extension portion 42. An opening 66 extending in the front-rear direction is formed in the bottom wall portion of the busbar holding portion 64. When the holder 60 is attached to the battery assembly 1, the corresponding positive electrode 4 and negative electrode 5 adjacent to each other in the front-rear direction are placed in the opening 66 of each busbar holding portion 64.

[0040] Next, the cover 70 will be described. The cover 70, which is a resin molded product, serves to cover the pair of left and right body portions 21 of the main line circuit body 20 that is long in the front-rear direction and is placed on the pair of left and right circuit body holding portions 61 that are long in the front-rear direction of the holder 60, and the multiple branch line circuit bodies 30 that branch off from the body portions 21 (see FIG. 1). For this reason, as shown in FIG. 6, the cover 70 has a strip-like shape that extends long in the front-rear direction. Each member that constitutes the busbar module 10 has been described above.

[0041] In a complete attachment state in which the busbar module 10 is attached to the battery assembly 1, the stacked single cells 2 in the battery assembly 1 are electrically connected in series via the busbars 40. Furthermore, each busbar 40 is conductively connected to an external voltage detection device via the wiring pattern 38 of the corresponding branch circuit body 30, the electronic component 50, the wiring pattern 37 of the corresponding branch circuit body 30, the wiring pattern 26 located at the corresponding connection portion 23 of the main circuit body 20, and the connector 27 mounted on the coupling portion 22 of the main circuit body 20, in this order. This allows the voltage (potential) of each busbar 40 to be detected individually by the external voltage detection device. If an excessive current exceeding the rated current flows through the electronic component 50 for some reason, the electronic component 50 exerts a fuse function to cut off the electrical connection between the wiring patterns 37 and 38. This prevents an excessive current from flowing into the voltage detection device, thereby protecting the voltage detection device.

[0042] When the battery assembly 1 with the busbar module 10 attached is in use, each of the cells 2 constituting the battery assembly 1 expands and contracts in the stacking direction (front-rear direction) due to operating heat associated with charging and discharging, the temperature of the external environment, and the like. As a result, the battery assembly 1 also deforms so as to expand and contract in the stacking direction (front-rear direction). In addition, due to assembly tolerances when stacking the multiple cells 2, the size of the battery assembly 1 in the stacking direction (front-rear direction) generally varies for each manufactured battery assembly 1 (manufacturing variations may occur).

[0043] In this regard, in the busbar module 10, even if expansion and contraction in the stacking direction (front-to-back direction) of the battery assembly 1 occurs due to thermal deformation of each battery cell 2 or manufacturing variations in the battery assembly 1 occur, each of the multiple expansion and contraction sections 63 of the holder 60 expands and contracts in the front-to-back direction and each branch circuit body 30 bends easily, so that the expansion and contraction due to thermal deformation of the battery assembly 1 and manufacturing variations can be easily absorbed.

[0044] <Actions and Effects> As described above, according to the busbar module 10 of the present embodiment, the branch circuit body 30 made of a flexible substrate is electrically connected to the main circuit body 20 made of a flexible substrate, and the branch circuit body 30 extends from the main circuit body 20 so as to branch off. Therefore, when the battery assembly 1 expands or contracts in the stacking direction due to thermal deformation of each unit cell 2, the branch circuit body 30 bends or the like, and each busbar 40 can move in the stacking direction of the unit cells 2. Similarly, the branch circuit body 30 bends or the like, and thus can absorb the variation in size in the stacking direction of the battery assembly 1 caused by the assembly tolerance of the unit cells 2. In other words, the busbar module 10 of the present embodiment can easily accommodate the expansion and contraction of the battery assembly 1 and the manufacturing variation by the deformation of the branch circuit body 30. Here, a flexible substrate is generally more easily deformed flexibly with a much smaller force than the electric wire used in the conventional busbar module described above, even when it contains a large number of circuit structures. Therefore, the ease of assembly to the battery assembly 1 is improved. Therefore, the bus bar module 10 according to this embodiment is superior in ease of assembly to the battery assembly 1 and in adaptability to deformation of the battery assembly 1 and manufacturing variations, compared to the conventional bus bar module described above.

[0045] Furthermore, as another effect, since the main line circuit body 20 and the branch line circuit body 30 are separate, it is not necessary to process the flexible circuit body into a shape in which the branch line circuit body 30 branches off from the main line circuit body 20 (for example, the above-mentioned punching process) as compared to the case in which the main line circuit body 20 and the branch line circuit body 30 are configured from a common flexible circuit body. Therefore, it is possible to reduce the amount of scrap pieces discarded by such processing, and to improve productivity (i.e., yield). In addition, since the electronic component 50 is attached (i.e., mounted) to the branch line circuit body 30 that is separate from the main line circuit body 20, it is not necessary to use a large mounting device as compared to the case in which the main line circuit body 20 and the branch line circuit body 30 are configured from a common flexible circuit body. In other words, it is possible to properly mount the electronic component 50 on the branch line circuit body 30 regardless of the length or size of the main line circuit body 20.

[0046] Furthermore, the branch circuit body 30 has a curved shape composed of a pair of strip-shaped portions (second portion 33 and fourth portion 35) extending along the stacking direction (front-rear direction) and a connecting portion (third portion 34) connecting one end of one strip-shaped portion to one end of the other strip-shaped portion. Such a curved shape increases the flexibility of the branch circuit body 30, thereby further improving the ease of assembly to the battery assembly 1 and the ability to adapt to deformation and manufacturing variations of the battery assembly 1.

[0047] Furthermore, by aligning the first hole portion (through hole 24) of the main line circuit body 20 and the second hole portion (through hole 31a) of the branch line circuit body 30 so as to overlap each other (for example, by inserting a rod-shaped jig 80 into the first hole portion 24 and the second hole portion 31a), it is possible to suppress misalignment and the like when soldering the first wiring pattern (wiring pattern 26) and the second wiring pattern (wiring pattern 37). This improves the reliability of the electrical connection between the main line circuit body 20 and the branch line circuit body 30.

[0048] <Other aspects> The present invention is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and appropriate modifications, improvements, etc. are possible. In addition, the material, shape, size, number, arrangement location, etc. of each component in the above-described embodiments are arbitrary as long as the present invention can be achieved, and are not limited.

[0049] In the above embodiment, the branch circuit body 30 has a curved shape composed of a pair of strip-shaped portions (second portion 33 and fourth portion 35) extending along the stacking direction (front-rear direction) and a connecting portion (third portion 34) connecting one end of one strip-shaped portion to one end of the other strip-shaped portion. However, the branch circuit body 30 does not necessarily have to have such a curved shape.

[0050] Furthermore, in the above embodiment, the main line circuit body 20 has the first hole portion (the through hole 24), and the branch line circuit body 30 has the second hole portion (the through hole 31a). However, the main line circuit body 20 and the branch line circuit body 30 do not necessarily have to have the first hole portion and the second hole portion, respectively.

[0051] Here, the features of the embodiment of the bus bar module 10 according to the present invention described above will be briefly summarized and listed in the following [1] to [3].

[0052] [1] A busbar module (10) that is attached to a battery assembly (1) in which a plurality of unit cells (2) are stacked, a main line circuit body (20) made of a flexible substrate having a first wiring pattern (26) and arranged to extend along the stacking direction of the plurality of unit cells (2); a branch circuit body (30) formed of a flexible substrate having a second wiring pattern (37, 38), the second wiring pattern (37) being electrically connected to the first wiring pattern (26) and extending so as to branch off from the main circuit body (20); a bus bar (40) to be connected to each of the electrodes (4, 5) of the plurality of single cells (2); an electronic component (50) attached to a mounting surface of the branch circuit body (30) so as to connect the second wiring pattern (38) and the bus bar (40); a holder (60) that holds the bus bar (40) and is extendable and contractable along the stacking direction, Busbar module (10).

[0053] According to the busbar module having the configuration of [1] above, a branch circuit body (hereinafter also referred to as a branch line) made of a flexible substrate is electrically connected to a main circuit body (hereinafter also referred to as a trunk line) made of a flexible substrate, and the branch circuit body extends so as to branch from the main circuit body. Therefore, when the battery assembly expands or contracts in the stacking direction due to thermal deformation of each unit cell, the branch circuit body is bent, etc., so that each busbar can move in the stacking direction of the unit cells. Similarly, the branch circuit body is bent, etc., so that the size variation in the stacking direction of the battery assembly caused by the assembly tolerance of the unit cells can be absorbed. In other words, the busbar module having this configuration can easily accommodate the expansion and contraction of the battery assembly and manufacturing variation by deforming the branch circuit body. Here, a flexible substrate is generally more easily deformed with a much smaller force than the electric wire used in the conventional busbar module described above, even when it contains a large number of circuit structures. Therefore, the ease of assembly to the battery assembly is improved. Therefore, the bus bar module of this configuration is superior in ease of assembly into a battery assembly and in adaptability to deformations and manufacturing variations in the battery assembly, compared to the conventional bus bar module described above.

[0054] Furthermore, according to the busbar module having the above configuration, the main line circuit body and the branch line circuit body are prepared as separate bodies and then electrically connected to each other. Therefore, compared to the case where the main line circuit body and the branch line circuit body are configured as an integral, continuous flexible substrate, it is not necessary to process the flexible substrate into a shape in which the branch line circuit body branches off from the main line circuit body (for example, punching out the original plate of the flexible substrate and processing it into a shape in which the branch line circuit body branches off from the main line circuit body). Therefore, it is possible to reduce the amount of scrap pieces discarded by such processing, and to improve productivity (i.e., yield). In particular, it is possible to improve productivity in that the original plate portion sandwiched between adjacent branch line circuits in the stacking direction is not discarded. In addition, since electronic components are attached (i.e., mounted) to the branch line circuit body prepared as a separate body from the main line circuit body, compared to the case where the main line circuit body and the branch line circuit body are configured as an integral flexible substrate, a large mounting device is not required for mounting electronic components. In other words, regardless of the length or size of the main line circuit body, electronic components can be properly mounted on the branch line circuit body using a general mounting device, thereby reducing the manufacturing costs of the busbar module.

[0055] [2] In the busbar module (10) described in [1] above, The branch circuit body (30) is At least a portion of the branch circuit body (30) has a curved shape including a pair of strip-shaped portions (33, 35) extending along the stacking direction and a connecting portion (34) connecting one end of one of the strip-shaped portions (33) to one end of the other of the strip-shaped portions (35). Busbar module (10).

[0056] According to the busbar module having the configuration [2] above, the branch circuit body has a curved shape (e.g., a U-shaped curved shape) that is composed of a pair of strip-shaped portions extending along the stacking direction and a connecting portion that connects one end of one strip-shaped portion to one end of the other strip-shaped portion. Such a curved shape further increases the flexibility of the branch circuit body, thereby further improving the ease of assembly to the battery assembly and the ability to adapt to deformation and manufacturing variations in the battery assembly.

[0057] [3] In the busbar module (10) described in [1] above, The main line circuit body (20) has a first hole portion (24) penetrating the main line circuit body (20) in a thickness direction, The branch line circuit body (30) has a second hole portion (31a) penetrating the branch line circuit body (30) in a thickness direction, The first wiring pattern (26) and the second wiring pattern (37) are electrically connected in a state where the first hole portion (24) and the second hole portion (31a) are aligned so as to overlap each other. Busbar module (10).

[0058] According to the busbar module having the configuration [3] above, by aligning the first hole portion of the main line circuit body and the second hole portion of the branch line circuit body so as to overlap each other (for example, by inserting a rod-shaped jig into the first hole portion and the second hole portion), it is possible to suppress misalignment between the first wiring pattern and the second wiring pattern when electrically connecting (for example, soldering) the two wiring patterns. This makes it possible to improve the reliability of the electrical connection between the main line circuit body and the branch line circuit body. [Explanation of symbols]

[0059] 1 battery assembly 2 D cells 4 Positive electrode 5. Negative electrode 10 Busbar module 20 Main circuit body 24 Through hole (first hole) 26 Wiring pattern (first wiring pattern) 30 Branch line circuit body 31a Through hole (second hole) 33 Second part (one of the strips) 34 Third part (connection part) 35 Fourth part (other belt) 37 Wiring pattern (second wiring pattern) 38 Wiring pattern (second wiring pattern) 40 Bus bar 50 Electronic Components 60 Holder

Claims

1. A busbar module that is attached to a battery assembly in which a plurality of unit cells are stacked, A main line circuit body that is made of a flexible substrate having a first wiring pattern and is disposed so as to extend along the stacking direction of the plurality of unit cells; a branch circuit body that is formed from a flexible substrate having a second wiring pattern, is separate from the main circuit body, the second wiring pattern is electrically connected to the first wiring pattern, and extends so as to branch off from the main circuit body; A bus bar to be connected to each electrode of the plurality of unit cells; an electronic component attached to a mounting surface of the branch circuit body so as to connect the second wiring pattern and the bus bar; a holder that holds the bus bar and is extendable and contractible along the stacking direction, a pair of first openings, through which the first wiring pattern is exposed, are provided in a connection portion of the main line circuit body for connecting the branch line circuit body to the main line circuit body, the first openings being arranged side by side with a gap therebetween in the stacking direction; a circuit body side connection portion, which is a portion of the branch circuit body connected to the connection portion of the main circuit body, has a pair of second openings, through which the second wiring pattern is exposed, the second openings being arranged side by side with a gap in between in the stacking direction and corresponding to the pair of first openings; the first wiring pattern exposed from the pair of first openings and the second wiring pattern exposed from the pair of second openings are soldered together, so that the first wiring pattern and the second wiring pattern are electrically connected to each other; Busbar module.

2. The busbar module according to claim 1, The branch circuit body is At least a portion of the branch circuit body has a curved shape including a pair of strip-shaped portions extending along the stacking direction and a connecting portion connecting one end of one of the strip-shaped portions to one end of the other of the strip-shaped portions. Busbar module.

3. A busbar module attached to a battery assembly in which a plurality of single cells are stacked, A main line circuit body that is made of a flexible substrate having a first wiring pattern and is disposed so as to extend along the stacking direction of the plurality of unit cells; a branch circuit body that is formed of a flexible substrate having a second wiring pattern, the second wiring pattern being electrically connected to the first wiring pattern and extending so as to branch off from the main circuit body; A bus bar to be connected to each electrode of the plurality of unit cells; an electronic component attached to a mounting surface of the branch circuit body so as to connect the second wiring pattern and the bus bar; a holder that holds the bus bar and is extendable and contractible along the stacking direction, the main line circuit body has a first hole portion penetrating the main line circuit body in a thickness direction, the branch circuit body has a second hole portion penetrating the branch circuit body in a thickness direction, The first wiring pattern and the second wiring pattern are electrically connected in a state where the first hole portion and the second hole portion are aligned so as to overlap each other. Busbar module.

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