Bus bar module

Abstract

To provide a bus bar module which is excellent in the assembling performance to a battery aggregate and in the followability to deformation or manufacturing variations of the battery aggregate.SOLUTION: A bus bar module 10 to be attached to a battery aggregate 1 including a plurality of single batteries 2 deposited on each other includes: a first circuit body 20A made of a flexible substrate with a first wire pattern 26 and having a first main line 21 and a first branch line 22; a second circuit body 20B made of a flexible substrate with a second wire pattern 26 and having a second main line 21 and a second branch line 22; an electronic component 50 attached to the first and second branch line units 22 to connect the first and second wire patterns 26 and the bus bar 40 to each other; and a holder 60 for holding the first circuit body 20A, the second circuit body 20B, and the bus bar 40, the holder being extendable along the deposition direction. An overlapping part 23 of the first and second main lines 21 is electrically connected to the first and second wire patterns 26.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, a bus bar module has been used, for example, to be assembled to a battery assembly (that is, a battery module in which a plurality of battery cells are stacked) as a driving power source mounted on an electric vehicle or a hybrid vehicle (see, for example, Patent Document 1).

[0003] The bus bar module described in Patent Document 1 includes a plurality of bus bars that connect between the positive electrode and the negative electrode between adjacent battery cells stacked thereon, and voltage detection lines that are connected to each of the plurality of bus bars to monitor each battery cell. This voltage detection line is configured to bundle a plurality of electric wires having a general structure in which a core wire is covered with an insulating coating.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, generally, the battery cells constituting the battery assembly expand and contract in the stacking direction due to the operating heat accompanying charge and discharge, the temperature of the external environment, and the like. As a result, the battery assembly (battery module) also deforms so as to expand and contract in the stacking direction of the battery cells. In addition, due to the assembly tolerance when stacking a plurality of battery cells, generally, the size of the battery assembly in the stacking direction may differ for each manufactured battery assembly (that is, manufacturing variations may occur). Therefore, generally, the bus bar module is designed to have a certain margin in the length of the voltage detection line in order to cope with such deformation and manufacturing variations of the battery assembly.

[0006] However, in the conventional bus bar 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 these numerous wires are bundled to form the voltage detection line, the rigidity of the entire voltage detection line (and thus the rigidity of the bus bar module) increases, making it difficult to improve the workability (assemblability) of assembling the bus bar module to the battery assembly. For the same reason, there is also a possibility that the bus bar module becomes less likely to expand and contract so as to sufficiently cope with deformation and manufacturing variations of the battery assembly.

[0007] One object of the present invention is to provide a bus bar module that is excellent in assemblability to a battery assembly and in followability to deformation and manufacturing variations of the battery assembly.

Means for Solving the Problems

[0008] In order to achieve the above-described object, the bus bar module according to the present invention is characterized as follows.

[0009] A bus bar module attached to a battery assembly in which a plurality of single cells are stacked, A first circuit body composed of a flexible substrate having a first wiring pattern, and having a first main line portion arranged to extend along the stacking direction of the plurality of single cells, and a first branch line portion extending so as to branch from the first main line portion, A second circuit body composed of a flexible substrate having a second wiring pattern, and having a second main line portion arranged to extend along the stacking direction, and a second branch line portion extending so as to branch from the second main line portion, A bus bar that is to be connected to the electrodes of each of the plurality of single cells, An electronic component attached to the first branch line portion and the second branch line portion so as to connect the bus bar corresponding to the first wiring pattern and the second wiring pattern, It is stretchable along the stacking direction, and includes a holder that holds the first circuit body, the second circuit body, and the bus bar. In the overlapping portion of the first main line portion and the second main line portion, the first wiring pattern and the second wiring pattern are electrically connected. It is a bus bar module.

Advantages of the Invention

[0010] According to the bus bar module of the present invention, a first circuit body and a second circuit body (hereinafter also referred to as "main lines") composed of flexible substrates are integrated by electrically connecting a first wiring pattern and a second wiring pattern in an overlapping portion of a first main line portion of the first circuit body and a second main line portion of the second circuit body. In other words, the first circuit body and the second circuit body are electrically connected. Further, first branch line portions and second branch line portions (hereinafter also referred to as "branch lines") extend so as to branch from the first main line portion and the second main line portion. Therefore, when the battery assembly expands and contracts in the stacking direction due to thermal deformation of each single battery, the branch lines bend or the like, so that each bus bar can move in the stacking direction of the single battery. Similarly, the branch lines bend or the like, so that variations in the size of the battery assembly in the stacking direction due to assembly tolerances of the single batteries can be absorbed. In other words, the bus bar module of this configuration can easily cope with expansion and contraction of the battery assembly and manufacturing variations by deforming the branch lines. Here, a flexible substrate is generally much more easily deformed flexibly with a much smaller force than the electric wires used in the conventional bus bar modules described above, even when it contains a large number of circuit structures. Therefore, the assemblability to the battery assembly is improved. Therefore, the bus bar module of this configuration is superior in assemblability to the battery assembly and followability to deformation and manufacturing variations of the battery assembly compared to the conventional bus bar modules described above.

[0011] Furthermore, according to the bus bar module with the above configuration, the first circuit body and the second circuit body are electrically connected after being prepared as separate bodies. Therefore, compared with the case where the first circuit body and the second circuit body are formed of an integral flexible substrate, the lengths of the first circuit body and the second circuit body in the stacking direction are shortened. Therefore, when attaching (i.e., mounting) electronic components to the first branch portion and the second branch portion, a dedicated large-scale mounting device is not required. In other words, even when the length and size of the final main line to which the first circuit body and the second circuit body are connected are not suitable for a general (universal) mounting device, after appropriately mounting electronic components on the branch circuit body using a general (universal) mounting device for each of the first circuit body and the second circuit body, the first circuit body and the second circuit body may be connected, so that the manufacturing cost of the bus bar module can be reduced.

[0012] The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments for carrying out the invention described below with reference to the accompanying drawings.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

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

[0015] Hereinafter, for convenience of explanation, as shown in FIG. 1 and the like, “front”, “rear”, “left”, “right”, “up” and “down” are defined. The “front-rear direction”, “left-right direction” and “up-down direction” are orthogonal to each other. The front-rear direction coincides with the stacking direction of the plurality of single cells 2 constituting the battery assembly 1 (see FIGS. 1 and 2). Note that these directions are defined for convenience of explanation and do not necessarily correspond to the front-rear direction, left-right direction, and up-down direction of the vehicle when the bus bar module 10 is mounted on the vehicle.

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

[0017] In the battery assembly 1, by reversing the left-right positions of the positive electrodes 4 and negative electrodes 5 of the single cells 2 adjacent to each other in the front-rear direction, the positive electrodes 4 and negative electrodes 5 are alternately arranged in the front-rear direction at the left end and the right end of the upper surface of the battery assembly 1, and a plurality of single cells 2 are stacked.

[0018] Hereinafter, the bus bar module 10 will be described. As shown in FIGS. 1, 3, and 4, the bus bar module 10 includes a long circuit body 20 (see FIGS. 1 and 3) extending in the front-rear direction, a plurality of bus bars 40 (see FIG. 1) respectively connected to a plurality of branch line portions 22 (see FIG. 3) of the circuit body 20, a plurality of electronic components 50 (see FIG. 3) respectively mounted on the plurality of branch line portions 22, a holder 60 (see FIGS. 1 and 3) for holding the circuit body 20 and the bus bars 40, and a cover 70 (see FIG. 1) for covering the circuit body 20. Note that the main line portion 21 and the branch line portions 22 (see FIG. 3) of the circuit body 20 are also called "trunk line" and "branch line", respectively.

[0019] The circuit body 20 is composed of a flexible printed circuit (FPC) that can be easily bent. As can be understood from FIGS. 1 and 3, the circuit body 20 includes a pair of left and right first circuit bodies 20A extending in the front-rear direction with a space therebetween in the left-right direction, and a pair of left and right second circuit bodies 20B respectively connected to the rear sides of the pair of left and right first circuit bodies 20A and extending in the front-rear direction. Either one of the pair of left and right first circuit bodies 20A and the pair of left and right second circuit bodies 20B is connected in the left-right direction by a connecting portion 28 (see FIG. 1). A connector 29 (see FIG. 1) electrically connected to an external voltage detection device (not shown) or the like is mounted on the lower surface of the connecting portion 28.

[0020] Each of the first circuit body 20A and the second circuit body 20B includes a strip-shaped main line portion 21 extending in the front-rear direction, and at least one (in this example, a plurality of) branch line portion 22 extending outward in the left-right direction from at least one (in this example, a plurality of) location in the front-rear direction of the main line portion 21 (see FIG. 3). In this example, each branch line portion 22 extends from the main line portion 21 so as to have a U-shaped curved shape. Since the branch line portion 22 has a U-shaped curved shape, the flexibility of the branch line portion 22 in the front-rear, left-right, and up-down directions is enhanced. A metal contact portion 24 is provided on the upper surface of the tip of each branch line portion 22 so as to be exposed to the outside (see FIG. 3).

[0021] By connecting the circuit connection part 23 provided at the rear end part of the main line part 21 of the first circuit body 20A and the circuit connection part 23 provided at the front end part of the main line part 21 of the second circuit body 20B, the main line parts 21 of the first circuit body 20A and the second circuit body 20B are continuously connected to form a circuit body 20 extending in a row in the front-rear direction. Details of the structure of each circuit connection part 23 of the first circuit body 20A and the second circuit body 20B and the connection procedure between the circuit connection parts 23 will be described later.

[0022] Each of the first circuit body 20A and the second circuit body 20B is composed of a resin layer except for the portions where the contact part 24 provided on the branch line part 22 is exposed (see FIG. 3) and the portions where the contact part 25 (described later) provided on the circuit connection part 23 is exposed (see FIG. 3) on the entire surface thereof, and includes a plurality of wiring patterns 26 (see FIG. 3). Each wiring pattern 26 is a copper conductor extending in a strip shape and extends along the main line part 21 and the branch line part 22. Each of the first circuit body 20A and the second circuit body 20B is a so-called "single-sided flexible printed circuit board (single-sided FPC)" having a single wiring layer, and for each of the first circuit body 20A and the second circuit body 20B, a plurality of wiring patterns 26 are arranged on the single wiring layer.

[0023] At the location where the circuit connection parts 23 of the first circuit body 20A and the second circuit body 20B are connected, at least one (in this example, six) wiring pattern 26 belonging to the first circuit body 20A and at least one (in this example, six) wiring pattern 26 belonging to the second circuit body 20B are connected to each other one-to-one independently (see FIG. 3. Details will be described later).

[0024] The plurality of wiring patterns 26 included in the first circuit body 20A and the second circuit body 20B are each individually electrically connected to the connector 29 mounted on the connecting part 28 through the inside of the corresponding branch line part 22, the main line part 21, and the connecting part 28 in this order from the contact part 24 of the corresponding branch line part 22. Thereby, the contact parts 24 of each branch line part 22 belonging to the first circuit body 20A and the second circuit body 20B are individually conductively connected to an external voltage detection device through the connector 29 mounted on the connecting part 28.

[0025] At the tip of each branch line portion 22, an electronic component 50 is mounted, and an elongated flat plate-shaped metal connection terminal 41 connected to the bus bar 40 is connected (see FIG. 3 etc.). The connection terminal 41 may be a part of a substantially rectangular flat plate-shaped metal bus bar 40 (see FIG. 1), or may be a member separate from the bus bar 40 and joined to the bus bar 40 by soldering or the like. The electronic component 50 is typically a chip fuse. The electronic component 50 is mounted at the tip of the branch line portion 22 by soldering or the like so as to connect the contact portion 24 of the branch line portion 22 and the connection terminal 41. Thereby, for each branch line portion 22, the contact portion 24 (that is, the wiring pattern 26 extending from the contact portion 24) and the connection terminal 41 (that is, the bus bar 40) are electrically connected via the electronic component 50.

[0026] The mounting of such an electronic component 50 to the branch line portion 22 is performed individually on the branch line portion 22 belonging to the first circuit body 20A and the branch line portion 22 belonging to the second circuit body 20B in a state before the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B are connected (that is, in a state where each of the first circuit body 20A and the second circuit body 20B is in a single state). Therefore, compared with the case where the first circuit body 20A and the second circuit body 20B are constituted by a common (single) flexible substrate, since the length of each of the first circuit body 20A and the second circuit body 20B in the front-rear direction becomes shorter, a large mounting device is not required. In other words, because the first circuit body 20A and the second circuit body 20B are separate bodies, regardless of the length and size of the long circuit body 20 obtained by connecting the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B, the electronic component 50 can be properly mounted on each branch line portion 22, and the manufacturing cost of the bus bar module 10 can be reduced.

[0027] Next, the detailed structure of each circuit connection portion 23 of the first circuit body 20A and the second circuit body 20B, and the connection procedure between the circuit connection portions 23 will be described. As shown in FIG. 3, on the upper surface of the circuit connection portion 23 of the first circuit body 20A, a plurality (six in this example) of metal contact portions (pads) 25 are provided so as to be arranged at intervals in the front-rear direction and to be exposed to the outside. Wiring patterns 26 individually extend from each contact portion 25. More specifically, for each of the three contact portions 25 on the front side (the base end side of the circuit connection portion 23) among the six contact portions 25, the wiring pattern 26 extends from the contact portion 25 to one side (left side) in the width direction (left-right direction) of the main line portion 21 of the first circuit body 20A, and then extends forward. For each of the three contact portions 25 on the rear side (the tip end side of the circuit connection portion 23) among the six contact portions 25, the wiring pattern 26 extends from the contact portion 25 to the other side (right side) in the width direction (left-right direction) of the main line portion 21 of the first circuit body 20A, and then extends forward.

[0028] In this way, by dispersedly arranging the extending portions of the plurality of wiring patterns 26 extending from the plurality of contact portions 25 in the left-right direction, it is possible to contribute to an improvement in the degree of freedom of the pattern design of the extending portions of the wiring patterns 26 extending from the contact portions 25, miniaturization of the circuit connection portion 23 (that is, the first circuit body 20A), and the like. On the upper surface of the circuit connection portion 23 of the first circuit body 20A, a metal dummy contact portion (land) 27 is provided so as to be exposed to the outside at a position that does not interfere with the contact portion 25 and the wiring pattern 26. The dummy contact portion 27 is not connected (electrically connected) to the wiring pattern 26 (that is, the bus bar 40). In the circuit connection portion 23 of the first circuit body 20A, holes 31 penetrating in the thickness direction (up-down direction) of the circuit connection portion 23 are formed at a plurality of positions (two in this example) that do not interfere with the contact portion 25, the wiring pattern 26, and the dummy contact portion 27.

[0029] On the lower surface of the circuit connection portion 23 of the second circuit body 20B, a plurality (six in this example) of metal contact portions (pads) 25 are provided so as to be arranged at intervals in the front-rear direction and to be exposed to the outside, corresponding to the plurality of contact portions 25 of the first circuit body 20A. Wiring patterns 26 extend individually from each contact portion 25. More specifically, for each of the three contact portions 25 on the front side (the tip side of the circuit connection portion 23) among the six contact portions 25, the wiring pattern 26 extends from the contact portion 25 to the other side (right side) in the width direction (left-right direction) of the main line portion 21 of the second circuit body 20B, and then extends rearward. For each of the three contact portions 25 on the rear side (the base end side of the circuit connection portion 23) among the six contact portions 25, the wiring pattern 26 extends from the contact portion 25 to one side (left side) in the width direction (left-right direction) of the main line portion 21 of the second circuit body 20B, and then extends rearward.

[0030] In this way, by dispersedly arranging the extending portions of the plurality of wiring patterns 26 extending from the plurality of contact portions 25 in the left-right direction, it is possible to contribute to an improvement in the degree of freedom of the pattern design of the extending portions of the wiring patterns 26 extending from the contact portions 25, miniaturization of the circuit connection portion 23 (that is, the second circuit body 20B), and the like. On the lower surface of the circuit connection portion 23 of the second circuit body 20B, a metal dummy contact portion (land) 27 is provided at a location that does not interfere with the contact portions 25 and the wiring patterns 26 so as to be exposed to the outside, corresponding to the dummy contact portion 27 of the first circuit body 20A. The dummy contact portion 27 is not connected (electrically connected) to the wiring pattern 26 (that is, the bus bar 40). In the circuit connection portion 23 of the second circuit body 20B, corresponding to the plurality of hole portions 31 of the first circuit body 20A, hole portions 31 penetrating in the thickness direction (up-down direction) of the circuit connection portion 23 are formed at a plurality of locations (two locations in this example) that do not interfere with the contact portions 25, the wiring patterns 26, and the dummy contact portion 27.

[0031] The connection operation between the circuit connection parts 23 of the first circuit body 20A and the second circuit body 20B is performed by using a plurality (two in this example) of protrusions 61a (see FIG. 3) provided at a plurality of locations (two locations in this example) on the bottom wall of the circuit body holding part 61 (see FIG. 3) of the holder 60 corresponding to the plurality of hole parts 31 of the first circuit body 20A and the second circuit body 20B. That is, first, with the circuit connection part 23 of the first circuit body 20A disposed below the circuit connection part 23 of the second circuit body 20B, the plurality of protrusions 61a are inserted into the plurality of hole parts 31 of the first circuit body 20A and the plurality of hole parts 31 of the second circuit body 20B in this order from below (see FIG. 4). Thereby, the first circuit body 20A and the second circuit body 20B are accommodated in the holder 60 (circuit body holding part 61), and a state is obtained in which the plurality of hole parts 31 of the first circuit body 20A and the plurality of hole parts 31 of the second circuit body 20B are aligned so as to overlap in the vertical direction.

[0032] Next, a plurality of contact parts 25 of the first circuit body 20A and a plurality of contact parts 25 of the second circuit body 20B are soldered one-to-one independently of each other, and a dummy contact part 27 of the first circuit body 20A and a dummy contact part 27 of the second circuit body 20B are soldered. These soldering operations can typically be performed by a method (so-called pulse heat method) in which a paste-like solder is sandwiched between the opposing contact parts 25 and the dummy contact parts 27 arranged in the vertical direction, and then a heater chip capable of heating the solder to a meltable temperature is pressed against the soldering location and the heater chip is heated to perform soldering. Note that the soldering can also be performed by a reflow method using a heating furnace. Further, the electrical connection between the circuit connection parts 23 of the first circuit body 20A and the second circuit body 20B may be performed using a conductive adhesive instead of the above-described soldering.

[0033] As a result, at the location where the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B are connected, a plurality of wiring patterns 26 belonging to the first circuit body 20A and a plurality of wiring patterns 26 belonging to the second circuit body 20B are electrically connected to each other one-to-one independently and are also integrated mechanically. Further, the dummy contact portion 27 of the first circuit body 20A and the dummy contact portion 27 of the second circuit body 20B are mechanically integrated using solder, a conductive adhesive, or the like. Thereby, the first circuit body 20A and the second circuit body 20B can be integrated more firmly.

[0034] In this way, by using the hole portions 31 of the first circuit body 20A, the hole portions 31 of the second circuit body 20B, and the protruding portions 61a of the holder 60, the operation of housing the first circuit body 20A and the second circuit body 20B in the holder 60 (circuit body holding portion 61) and the operation of electrically connecting the contact portions 25 (wiring patterns 26) of both while suppressing displacement and the like of the contact portions 25 of both by the protruding portions 61a can be carried out together. Further, when an unintended external force is applied to the circuit body 20 after connection (more specifically, the main wire portions 21 of the first circuit body 20A and the second circuit body 20B), by receiving the external force with the protruding portions 61a, it is possible to suppress the external force from reaching the connection portion of the contact portions 25 (wiring patterns 26) of both. Therefore, the reliability of the electrical connection between the first circuit body 20A and the second circuit body 20B can be improved.

[0035] Next, the holder 60 will be described. The holder 60 is a resin molded product and, as shown in FIG. 1, integrally includes a pair of left and right strip-shaped circuit body holding portions 61 that extend in the front-rear direction with a space in the left-right direction, and a plurality of connecting portions 62 that connect the pair of left and right circuit body holding portions 61 in the left-right direction at a plurality of locations in the front-rear direction. On the pair of left and right circuit body holding portions 61, a pair of left and right first circuit bodies 20A (main wire portion 21 + branch wire portion 22) and a second circuit body 20B (main wire portion 21 + branch wire portion 22) of the circuit body 20 are placed.

[0036] Each of the pair of circuit body holders 61 extending in the front-rear direction is specifically composed of a plurality of divided bodies (not shown) arranged side by side in the front-rear direction and a telescopic portion (not shown) that connects adjacent divided bodies in the front-rear direction. Each telescopic portion has a shape that can be easily expanded and contracted in the front-rear direction by elastic deformation. Therefore, the pair of circuit body holders 61 is configured to be expandable and contractible along the front-rear direction. As described above, a plurality (two) of protrusions 61a are provided on the bottom wall of each circuit body holder 61 (see FIG. 3).

[0037] For each of the left and right pair of circuit body holders 61, a bus bar holder 64 (see FIG. 1) is integrally provided adjacent to the outside in the left-right direction on each of the plurality of divided bodies arranged side by side in the front-rear direction. That is, on the outside in the left-right direction of each of the left and right pair of circuit body holders 61, a plurality of bus bar holders 64 are arranged side by side in the front-rear direction. Since each bus bar holder 64 is provided on the corresponding divided body, the distance in the front-rear direction between adjacent bus bar holders 64 in the front-rear direction can be varied by the function of the telescopic portion.

[0038] Each bus bar holder 64 houses the corresponding bus bar 40. When the holder 60 is attached to the battery assembly 1, the bus bar 40 housed in each bus bar holder 64 is conductively connected to the corresponding positive electrode 4 and negative electrode 5 adjacent in the front-rear direction on the upper surface of the battery assembly 1.

[0039] Next, the cover 70 will be described. The cover 70, which is a resin molded product, functions to cover the circuit bodies 20 placed on the left and right pair of circuit body holders 61 that are long in the front-rear direction of the holder 60, that is, the first circuit body 20A (main line portion 21 + branch line portion 22) and the second circuit body 20B (main line portion 21 + branch line portion 22) (see FIG. 1). Therefore, as shown in FIG. 1, the cover 70 has a strip-like shape that extends long in the front-rear direction.

[0040] In the state where the bus bar module 10 is attached to the battery assembly 1, in the battery assembly 1, a plurality of stacked single cells 2 are electrically connected in series via a plurality of bus bars 40. Further, each bus bar 40 is conductively connected to an external voltage detection device via an electronic component 50 mounted on a corresponding branch portion 22, a wiring pattern 26 extending from the corresponding branch portion 22 (contact portion 24), and a connector 29 mounted on a connecting portion 28 in this order. Thereby, the voltage (potential) of each bus bar 40 can be individually detected by an external voltage detection device. In addition, if an excessive current exceeding the rated current flows through the electronic component 50 for some reason, the fuse function of the electronic component 50 is exerted, and the electrical connection between the bus bar 40 and the wiring pattern 26 is cut off by the electronic component 50. Thereby, since the inflow of an excessive current into the voltage detection device is prevented, the voltage detection device can be protected.

[0041] In the usage state of the battery assembly 1 to which the bus bar module 10 is attached, each single cell 2 constituting the battery assembly 1 expands and contracts in the stacking direction (front-rear direction) due to the operating heat accompanying charge and discharge, 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). Further, due to the assembly tolerance when stacking and arranging a plurality of single cells 2, generally, the size of the battery assembly 1 in the stacking direction (front-rear direction) may differ for each manufactured battery assembly 1 (manufacturing variations may occur).

[0042] In this regard, in the bus bar module 10, even if the expansion and contraction of the battery assembly 1 in the stacking direction (front-rear direction) due to the thermal deformation of each single cell 2 and the manufacturing variations of the battery assembly 1 occur, each of the plurality of expansion and contraction portions of the holder 60 expands and contracts in the front-rear direction, and each branch portion 22 made of a flexible substrate easily bends, so that the expansion and contraction and manufacturing variations due to the thermal deformation of the battery assembly 1 can be easily absorbed.

[0043] <Function and Effect> As described above, according to the bus bar module 10 according to the present embodiment, the first circuit body 20A and the second circuit body 20B (main line) formed of flexible substrates are electrically connected to each other at the overlapping portions (circuit connection portions 23) of the main line portions 21 of the first circuit body 20A and the main line portions 21 of the second circuit body 20B, and are integrated. In other words, the first circuit body 20A and the second circuit body 20B are electrically connected. Further, branch line portions 22 (branch lines) extend so as to branch from the main line portions 21 of the first circuit body 20A and the second circuit body 20B. For this reason, when the battery assembly 1 expands and contracts in the stacking direction (front-rear direction) due to thermal deformation of each single battery 2, the branch lines are bent or the like, so that each bus bar 40 can move in the stacking direction of the single battery 2. Similarly, the branch lines are bent or the like, so that variations in the size of the battery assembly 1 in the stacking direction (front-rear direction) due to the assembly tolerance of the single battery 2 can be absorbed. In other words, the bus bar module 10 according to the present embodiment can easily cope with the expansion and contraction of the battery assembly 1 and manufacturing variations by deforming the branch lines. Here, a flexible substrate generally deforms flexibly with a much smaller force than an electric wire used in the conventional bus bar module described above, even when including a large number of circuit structures. Therefore, the assemblability to the battery assembly 1 is improved. Accordingly, the bus bar module 10 according to the present embodiment is excellent in assemblability to the battery assembly 1 and followability to deformation and manufacturing variations of the battery assembly 1 as compared with the conventional bus bar module described above.

[0044] Furthermore, according to the bus bar module 10 according to the present embodiment, the first circuit body 20A and the second circuit body 20B are prepared as separate bodies and then electrically connected. Therefore, compared with the case where the first circuit body 20A and the second circuit body 20B are formed of a single flexible substrate, the lengths of the first circuit body 20A and the second circuit body 20B in the stacking direction (front-rear direction) are shortened. Therefore, when attaching (i.e., mounting) the electronic component 50 to each branch line portion 22, a dedicated large-scale mounting device is not required. In other words, even when the length and size of the final main line to which the first circuit body 20A and the second circuit body 20B are connected are not suitable for a general (general-purpose) mounting device, after properly mounting the electronic component 50 to the branch line portion 22 using a general (general-purpose) mounting device for each of the first circuit body 20A and the second circuit body 20B, the first circuit body 20A and the second circuit body 20B may be connected, so that the manufacturing cost of the bus bar module 10 can be reduced.

[0045] Furthermore, according to the bus bar module 10 according to the present embodiment, by aligning the hole portion 31 of the first circuit body 20A and the hole portion 31 of the second circuit body 20B so as to overlap (for example, inserting a protrusion 61a or a rod-shaped jig as in this example into the hole portions 31 of the first circuit body 20A and the second circuit body 20B), when electrically connecting (for example, soldering) the wiring patterns 26 of the first circuit body 20A and the second circuit body 20B, misalignment or the like between the two wiring patterns 26 can be suppressed. Therefore, the reliability of the electrical connection between the first circuit body 20A and the second circuit body 20B can be improved.

[0046] Furthermore, according to the bus bar module 10 according to the present embodiment, the holder 60 has a protrusion 61a that is inserted into the hole 31 of the first circuit body 20A and the hole 31 of the second circuit body 20B. Thereby, the operation of accommodating the first circuit body 20A and the second circuit body 20B in the holder 60 and the operation of electrically connecting the two wiring patterns 26 while regulating the positions of the two wiring patterns 26 with the protrusion 61a can be performed together. Furthermore, when an unintended external force is applied to the main line (the first circuit body 20A and the second circuit body 20B) after connection, by receiving the external force with the protrusion 61a, it is possible to suppress the external force from reaching the connection portion of the two wiring patterns 26. Therefore, the reliability of the electrical connection between the first circuit body 20A and the second circuit body 20B can be improved.

[0047] Furthermore, according to the bus bar module 10 according to the present embodiment, the wiring patterns 26 of the first circuit body 20A and the second circuit body 20B are joined so as to be electrically conductive by a conductive bonding material. Thereby, in addition to electrically connecting the two wiring patterns 26, the first circuit body 20A and the second circuit body 20B are also mechanically integrated.

[0048] Furthermore, according to the bus bar module 10 according to the present embodiment, in addition to the joining of the wiring patterns 26 of the first circuit body 20A and the second circuit body 20B, the dummy contact portions 27 of the first circuit body 20A and the second circuit body 20B are joined. Thereby, the first circuit body 20A and the second circuit body 20B can be more firmly integrated.

[0049] <Other aspects> Note that 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 can be appropriately modified, improved, etc. In addition, the material, shape, dimensions, 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.

[0050] <First modification example> In the above-described embodiment, each of the first circuit body 20A and the second circuit body 20B is a so-called single-sided flexible printed circuit board (single-sided FPC) having a single wiring layer. Then, the circuit body 20 is configured by connecting the circuit connection portion 23 provided at the rear end portion of the first circuit body 20A and the circuit connection portion 23 provided at the front end portion of the second circuit body 20B.

[0051] In contrast, as in the first modification example shown in FIG. 5, the circuit connection portion 23 provided at the rear end portion of the first circuit body 20A and the circuit connection portion 23 provided at the front end portion of the second circuit body 20B are connected, and the circuit connection portion 23 provided at the rear end portion of the second circuit body 20B and the circuit connection portion 23 provided at the front end portion of the third circuit body 20C are connected. Thus, the circuit body 20 may be configured. Here, each of the first circuit body 20A and the third circuit body 20C may be a so-called single-sided flexible printed circuit board (single-sided FPC) having a single wiring layer, and the second circuit body 20B may be a so-called double-sided flexible printed circuit board (double-sided FPC) having a plurality of wiring layers.

[0052] In the second circuit body 20B, a part of the wiring pattern 26 is disposed on one wiring layer, and the other part of the wiring pattern 26 is disposed on the other wiring layer, and a part and the other part of the wiring pattern 26 are connected through the layers. Further, the arrangement order of the wiring patterns 26 in the width direction (left-right direction) of the second circuit body 20B is different between one wiring layer and the other wiring layer. Thereby, the arrangement order of the wiring patterns 26 in the first circuit body 20A and the third circuit body 20C can be rearranged in an arbitrary order (for example, interchanged in the potential order of the bus bar 40 to which the wiring pattern 26 is connected) through the second circuit body 20B. Thereby, compared with the case where the entire first circuit body 20A, the second circuit body 20B, and the third circuit body 20C are configured by a double-sided flexible printed circuit board, the manufacturing cost of the bus bar module 10 can be reduced.

[0053] <Second modification example, Third modification example> In the above-described embodiment, in each of the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B, a plurality of contact portions 25 are arranged at intervals in the front-rear direction (the longitudinal direction of the circuit body 20).

[0054] In contrast, as in the second modification example shown in FIG. 6, at each circuit connection portion 23 of the first circuit body 20A and the second circuit body 20B, a plurality of contact portions 25 may be arranged at intervals in the left-right direction (width direction of the circuit body 20). In the second modification example, in a state where the lower surfaces of the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B are bent so as to face each other in the front-rear direction, the contact portion 25 exposed on the lower surface of the circuit connection portion 23 of the first circuit body 20A and the contact portion 25 exposed on the lower surface of the circuit connection portion 23 of the second circuit body 20B are joined to each other, thereby constituting the circuit body 20.

[0055] Furthermore, as in the third modification example shown in FIG. 7, at each circuit connection portion 23 of the first circuit body 20A and the second circuit body 20B, a plurality of contact portions 25 may be arranged at intervals in the left-right direction (width direction of the circuit body 20). In the third modification example, in a state where the circuit connection portion 23 of the first circuit body 20A is arranged so as to overlap the lower side of the circuit connection portion 23 of the second circuit body 20B, the contact portion 25 exposed on the upper surface of the circuit connection portion 23 of the first circuit body 20A and the contact portion 25 exposed on the lower surface of the circuit connection portion 23 of the second circuit body 20B are joined to each other, thereby constituting the circuit body 20. In the third modification example, a plurality of connection portions between the contact portion 25 of the first circuit body 20A and the contact portion 25 of the second circuit body 20B are arranged at intervals in the left-right direction. Between adjacent connection portions, slit-shaped through holes 71 penetrating the circuit connection portion 23 of the first circuit body 20A and the circuit connection portion 23 of the second circuit body 20B in the thickness direction (up-down direction) are provided. By these through holes 71, even when the bus bar module 10 is temporarily flooded with water or the like, it is possible to suppress short-circuiting between adjacent connection portions due to moisture or the like.

[0056] Here, the features of the embodiments of the bus bar module 10 according to the present invention described above are briefly summarized and listed in [1] to [6] below, respectively.

[0057] [1] A bus bar module (10) attached to a battery assembly (1) in which a plurality of single batteries (2) are stacked, A first circuit body (20A) composed of a flexible substrate having a first wiring pattern (26), the first main line portion (21) being arranged to extend along the stacking direction of the plurality of single cells (2), and a first branch line portion (22) extending so as to branch from the first main line portion (21). A second circuit body (20B) composed of a flexible substrate having a second wiring pattern (26), the second main line portion (21) being arranged to extend along the stacking direction, and a second branch line portion (22) extending so as to branch from the second main line portion (21). A bus bar (40) to be connected to the electrodes (4, 5) of each of the plurality of single cells (2). An electronic component (50) attached to the first branch line portion (22) and the second branch line portion (22) so as to connect the first wiring pattern (26) and the bus bar (40) corresponding to the second wiring pattern (26). A holder (60) that is stretchable and contractible along the stacking direction and holds the first circuit body (20A), the second circuit body (20B), and the bus bar (40). In the overlapping portion (23) of the first main line portion (21) and the second main line portion (21), the first wiring pattern (26) and the second wiring pattern (26) are electrically connected. Bus bar module (10).

[0058] According to the bus bar module configured as described above [1], a first circuit body and a second circuit body (hereinafter also referred to as "main lines") each formed of a flexible substrate are integrated by electrically connecting a first wiring pattern and a second wiring pattern at an overlapping portion between a first main line portion of the first circuit body and a second main line portion of the second circuit body. In other words, the first circuit body and the second circuit body are electrically connected. Further, first branch line portions and second branch line portions (hereinafter also referred to as "branch lines") extend so as to branch from the first main line portion and the second main line portion. For this reason, when the battery assembly expands and contracts in the stacking direction due to thermal deformation of each single battery, the branch lines are bent or the like, so that each bus bar can move in the stacking direction of the single battery. Similarly, the branch lines are bent or the like, so that variations in the size of the battery assembly in the stacking direction due to assembly tolerances of the single batteries can be absorbed. In other words, the bus bar module of this configuration can easily cope with expansion and contraction of the battery assembly and manufacturing variations by deforming the branch lines. Here, in general, even when the flexible substrate includes a large number of circuit structures, it is more easily deformed with a much smaller force than the electric wire used for the conventional bus bar module described above. Therefore, the assemblability to the battery assembly is improved. Accordingly, the bus bar module of this configuration is superior in assemblability to the battery assembly and in followability to deformation and manufacturing variations of the battery assembly as compared with the conventional bus bar module described above.

[0059] Furthermore, according to the bus bar module configured as described above, the first circuit body and the second circuit body are electrically connected after being prepared as separate bodies. Therefore, compared with the case where the first circuit body and the second circuit body are formed of an integral flexible substrate, the lengths of the first circuit body and the second circuit body in the stacking direction are shortened. Therefore, when attaching (i.e., mounting) electronic components to the first branch line portions and the second branch line portions, a dedicated large mounting device is not required. In other words, even when the length and size of the final main line in which the first circuit body and the second circuit body are connected are not suitable for a general (universal) mounting device, after appropriately mounting electronic components on the branch line circuits using general (universal) mounting devices for each of the first circuit body and the second circuit body, the first circuit body and the second circuit body may be connected, so that the manufacturing cost of the bus bar module can be reduced.

[0060] [2] In the bus bar module (10) described in the above [1], the first circuit body (20A) has a first hole portion (31) penetrating the first circuit body (20A) in the thickness direction, the second circuit body (20B) has a second hole portion (31) penetrating the second circuit body (20B) in the thickness direction, the first wiring pattern (26) and the second wiring pattern (26) are electrically connected in a state where the first hole portion (31) and the second hole portion (31) are aligned so as to overlap each other. Bus bar module (10).

[0061] According to the bus bar module having the configuration of the above [2], by aligning the first hole portion of the first circuit body and the second hole portion of the second circuit body so as to overlap each other (for example, inserting a rod-shaped jig into the first hole portion and the second hole portion), during the electrical connection (for example, soldering) between the first wiring pattern and the second wiring pattern, misalignment and the like between the two wiring patterns can be suppressed. Therefore, the reliability of the electrical connection between the first circuit body and the second circuit body can be improved.

[0062] [3] In the bus bar module (10) described in the above [1], the first circuit body (20A) has a single wiring layer, and the first wiring pattern (26) is arranged on the single wiring layer, the second circuit body (20B) has a plurality of wiring layers, a part of the second wiring pattern (26) is arranged on one of the wiring layers, and the other part of the second wiring pattern (26) is arranged on another wiring layer, and the part and the other part of the second wiring pattern (26) are connected between layers, and the arrangement order of the second wiring pattern (26) in the width direction of the second circuit body (20B) is different between the one wiring layer and the other wiring layer. Bus bar module (10).

[0063] According to the bus bar module configured as described in [3] above, the first circuit body is a circuit body having a single wiring layer (for example, a single-sided flexible substrate), and the second circuit body is a circuit body having a plurality of wiring layers (for example, a double-sided flexible substrate). Further, in the second circuit body, the arrangement order of the second wiring patterns in the width direction is different between one wiring layer and the other wiring layer. Therefore, for example, the arrangement order of the first wiring patterns in the first circuit body can be rearranged in an arbitrary order (for example, the potentials of the bus bars to which the respective wirings constituting the first wiring patterns are connected can be swapped) through the second circuit body. Thereby, compared with the case where the entire first circuit body and the second circuit body are configured by a circuit body having a plurality of wiring layers, the manufacturing cost of the bus bar module can be reduced.

[0064] [4] In the bus bar module (10) described in [2] above, the holder (60) has a protrusion (61a) inserted into the first hole (31) and the second hole (31). Bus bar module (10).

[0065] According to the bus bar module configured as described in [4] above, the holder has protrusions inserted into the first hole of the first circuit body and the second hole of the second circuit body. Thereby, the operation of accommodating the first circuit body and the second circuit body in the holder and the operation of electrically connecting the two wiring patterns while regulating the positions of the two wiring patterns with the protrusions can be performed together. Further, when an unintended external force is applied to the main line (the first circuit body and the second circuit body) after connection, by receiving the external force with the protrusions, it is possible to suppress the external force from reaching the connection portion of the two wiring patterns. Therefore, the reliability of the electrical connection between the first circuit body and the second circuit body can be improved.

[0066] [5] In the bus bar module (10) described in [1] above, the first wiring pattern (26) and the second wiring pattern (26) are conductively joined by a conductive joining material so as to be electrically conductive. Bus bar module (10).

[0067] According to the bus bar module configured as described in [5] above, the first wiring pattern and the second wiring pattern are conductively joined by a conductive bonding material. Thereby, in addition to electrically connecting both wiring patterns, the first circuit body and the second circuit body are also mechanically integrated. Examples of the conductive bonding material include solder and conductive adhesive.

[0068] [6] In the bus bar module described in [5] above, the first circuit body (20A) has a first dummy wiring pattern (27) that is not connected to the bus bar (40), the second circuit body (20B) has a second dummy wiring pattern (27) that is not connected to the bus bar (40), and the first dummy wiring pattern (27) and the second dummy wiring pattern (27) are joined. Bus bar module (10).

[0069] According to the bus bar module configured as described in [6] above, in addition to the joining of the first wiring pattern and the second wiring pattern, the first dummy wiring pattern of the first circuit body and the second dummy wiring pattern of the second circuit body are joined. Thereby, the first circuit body and the second circuit body can be more firmly integrated.

Explanation of Reference Numerals

[0070] 1 Battery assembly 2 Single battery 4 Positive electrode (electrode) 5 Negative electrode (electrode) 10 Bus bar module 20A First circuit body 20B Second circuit body 21 Main wire part (first main wire part, second main wire part) 22 Branch wire part (first branch wire part, second branch wire part) 23 Circuit connection part (overlapping part) 26 Wiring pattern (first wiring pattern, second wiring pattern) 27 Dummy joints (first dummy wiring pattern, second dummy wiring pattern) 31 Hole parts (first hole part, second hole part) 40 Bus bar 50 Electronic component 60 Holder 61a Protrusion

Claims

1. A bus bar module attached to a battery assembly in which a plurality of single cells are stacked, a first circuit body composed of a flexible substrate having a first wiring pattern, the first main line portion arranged to extend along the stacking direction of the plurality of single cells, and a first branch line portion extending so as to branch from the first main line portion; a second circuit body composed of a flexible substrate having a second wiring pattern, the second main line portion arranged to extend along the stacking direction, and a second branch line portion extending so as to branch from the second main line portion; a bus bar to be connected to the electrodes of each of the plurality of single cells; electronic components attached to the first branch line portion and the second branch line portion so as to connect the bus bar corresponding to the first wiring pattern and the second wiring pattern; a holder that is stretchable along the stacking direction and holds the first circuit body, the second circuit body, and the bus bar; in an overlapping portion of the first main line portion and the second main line portion, the first wiring pattern and the second wiring pattern are electrically connected; a bus bar module.

2. The bus bar module according to claim 1, wherein the first circuit body has a first hole portion penetrating the first circuit body in the thickness direction; the second circuit body has a second hole portion penetrating the second circuit body in the 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; a bus bar module.

3. The bus bar module according to claim 1, wherein the first circuit body has a single wiring layer, and the first wiring pattern is arranged on the single wiring layer; the second circuit body has a plurality of wiring layers, a part of the second wiring pattern is arranged on one of the wiring layers, the other part of the second wiring pattern is arranged on another wiring layer, the part and the other part of the second wiring pattern are connected between layers, and the arrangement order of the second wiring pattern in the width direction of the second circuit body is different between the one wiring layer and the other wiring layer; a bus bar module.

4. The bus bar module according to claim 2, wherein the holder has a protrusion portion inserted into the first hole portion and the second hole portion; a bus bar module.

5. In the bus bar module according to claim 1, the first wiring pattern and the second wiring pattern are conductively joined by a conductive joining material so as to be electrically connected, bus bar module.

6. In the bus bar module according to claim 5, the first circuit body has a first dummy wiring pattern not connected to the bus bar, the second circuit body has a second dummy wiring pattern not connected to the bus bar, the first dummy wiring pattern and the second dummy wiring pattern are joined, bus bar module.

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