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 includes: a first circuit body 20A having a first wire pattern 26; a second circuit body 20B having a second wire pattern 26; and an electronic component 50 attached to first and second branch lines 22 to connect the first and second wire patterns 26 and a bus bar 40 to each other. An overlapping part 23 of the first and second main lines 21 is electrically connected to the first and second wire patterns 26. The bus bar module 10 also includes a water prevention part for sealing the overlapping part 23 to make the overlapping part 23 watertight.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, and voltage detection lines connected to each of the plurality of bus bars for monitoring each battery cell. This voltage detection line is configured by bundling 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, which may make 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 difficult 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 excellent in assemblability to a battery assembly and 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. The first wiring pattern has a plurality of first contact portions arranged in the stacking direction. The second wiring pattern has a plurality of second contact portions arranged in the stacking direction. In the overlapping portion of the first main line portion and the second main line portion, the plurality of first contact portions and the plurality of second contact portions are electrically connected to each other. It further includes a waterproof portion that seals the overlapping portion in a watertight manner. 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 contact portion of a first wiring pattern and a second contact portion of 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, a first branch line portion and a second branch line portion (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 more easily deformed flexibly with a much smaller force than the electric wires used in the conventional bus bar module described above, even when it includes 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 module described above.

[0011] Furthermore, according to the bus bar module having 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 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 bodies 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] Furthermore, according to the bus bar module having the above configuration, since the first circuit body and the second circuit body are electrically connected after being prepared as separate bodies, when the bus bar module is flooded with water or the like, there is a risk that liquid such as water may enter the overlapping portion (between the first main line portion and the second main line portion) of the first main line portion of the first circuit body and the second main line portion of the second circuit body. However, by providing a waterproof portion in which the bus bar module seals the overlapping portion in a watertight manner, it is possible to suppress the occurrence of a problem in which adjacent connection portions are electrically connected (short-circuited) by a liquid.

[0013] The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments (hereinafter referred to as "embodiments") for carrying out the invention described below with reference to the accompanying drawings.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0015] <First Embodiment> Hereinafter, the bus bar module 10 according to the first embodiment of the present invention will be described with reference to the drawings. 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.

[0016] Hereinafter, for the 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 that make up the battery assembly 1 (see FIGS. 1 and 2). Note that these directions are defined for the 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.

[0017] 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 is composed of 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.

[0018] In the battery assembly 1, the plurality of single cells 2 are stacked such that the left and 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 are reversed from each other, so that the positive electrodes 4 and negative electrodes 5 are alternately arranged in the front-rear direction at each of the left and right ends of the upper surface of the battery assembly 1.

[0019] 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 extending in the front-rear direction (see FIGS. 1 and 3), a plurality of bus bars 40 (see FIG. 1) respectively connected to a plurality of branch 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 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 portion 22 (see FIG. 3) of the circuit body 20 are also called “main trunk line” and “branch line”, respectively.

[0020] 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, 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 each connected to the rear side 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). On the lower surface of the connecting portion 28, a connector 29 (see FIG. 1) electrically connected to an external voltage detection device (not shown) or the like is mounted.

[0021] 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 portions 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. On the upper surface of the tip of each branch line portion 22, a metal contact portion 24 is provided so as to be exposed to the outside (see FIG. 3).

[0022] By connecting the circuit connection portion 23 provided at the rear end portion of the main line portion 21 of the first circuit body 20A and the circuit connection portion 23 provided at the front end portion of the main line portion 21 of the second circuit body 20B, the main line portions 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. As shown in FIGS. 3 to 5, the size of the circuit connection portion 23 of the first circuit body 20A in the width direction (left-right direction) is configured to be larger than the size of the second circuit body 20B in the width direction. 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 later.

[0023] Each of the first circuit body 20A and the second circuit body 20B has its entire surface formed of a resin layer except for the locations where the contact portions 24 provided on the branch line portion 22 are exposed (see FIG. 3) and the locations where the contact portions 25 (to be described later) provided on the circuit connection portion 23 are exposed (see FIG. 3), and encloses 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 portion 21 and the branch line portion 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 in the single wiring layer. However, each of the first circuit body 20A and the second circuit body 20B may be a "double-sided FPC".

[0024] At the location where the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B are connected to each other, at least one (six in this example) wiring pattern 26 belonging to the first circuit body 20A and at least one (six in this example) 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).

[0025] The plurality of wiring patterns 26 enclosed 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 portion 28 through the inside of the corresponding branch line portion 22, the corresponding branch line portion 22, the main line portion 21, and the connecting portion 28 in this order from the contact portion 24 of the corresponding branch line portion 22. Thereby, the contact portions 24 of each branch line portion 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 portion 28.

[0026] At the tip of each branch 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 on the tip of the branch portion 22 by soldering or the like so as to connect the contact portion 24 of the branch portion 22 and the connection terminal 41. Thereby, for each branch 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.

[0027] The mounting of such an electronic component 50 to the branch portion 22 is performed individually on the branch portion 22 belonging to the first circuit body 20A and the branch 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 composed of a common (single) flexible substrate, the length of each of the first circuit body 20A and the second circuit body 20B in the front-rear direction becomes shorter, so a large mounting device is not required. In other words, since 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 portion 22, and the manufacturing cost of the bus bar module 10 can be reduced.

[0028] Hereinafter, 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 extend individually 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.

[0029] In this way, by dispersing 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 at one location that does not interfere with the contact portion 25 and the wiring pattern 26 so as to be exposed to the outside. 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 locations (two locations in this example) that do not interfere with the contact portion 25, the wiring pattern 26, and the dummy contact portion 27.

[0030] 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 individually extend 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.

[0031] In this way, by dispersing and 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 one location that does not interfere with the contact portions 25 and the wiring patterns 26, corresponding to the dummy contact portion 27 of the first circuit body 20A, so as to be exposed to the outside. 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.

[0032] The connection operation between the circuit connection portions 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 portion 61 (see FIG. 3) of the holder 60 corresponding to the plurality of hole portions 31 of the first circuit body 20A and the second circuit body 20B. That is, first, with the circuit connection portion 23 of the first circuit body 20A disposed below the circuit connection portion 23 of the second circuit body 20B, the plurality of protrusions 61a are inserted into the plurality of hole portions 31 of the first circuit body 20A and the plurality of hole portions 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 portion 61), and a state is obtained in which the plurality of hole portions 31 of the first circuit body 20A and the plurality of hole portions 31 of the second circuit body 20B are aligned so as to overlap in the vertical direction.

[0033] Next, the plurality of contact portions 25 of the first circuit body 20A and the plurality of contact portions 25 of the second circuit body 20B are soldered one-to-one independently of each other, and the dummy contact portion 27 of the first circuit body 20A and the dummy contact portion 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 portions 25 and the dummy contact portions 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 for 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 portions 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.

[0034] 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.

[0035] 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 protrusion portions 61a of the holder 60, the operation of accommodating 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 or the like of the contact portions 25 of both by the protrusion portions 61a can be performed 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 protrusion 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.

[0036] After the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B are connected to each other, a coating material 32 is applied in a substantially rectangular U shape so as to close the gap between the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B at the edge portions 23a of the circuit connection portions 23 of both (more specifically, three sides out of four turns) (see FIGS. 4 and 5). Thereby, intrusion of a liquid such as water between the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B can be suppressed. That is, it is possible to suppress a problem in which conduction (short circuit) occurs between adjacent contact portions 25 due to a liquid. The coating material 32 is, for example, a known waterproof material, moisture-proof material, or the like.

[0037] The application of the coating material 32 to the edge portion 23a may be performed on all four sides, or may be performed on only one side. Further, instead of connecting the dummy contact portions 27 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 mechanically integrated by the coating material 32. Note that the order of the operation of applying the coating material 32 to the edge portion 23a and the operation of housing the first circuit body 20A and the second circuit body 20B in the holder 60 (circuit body holding portion 61) does not matter.

[0038] Next, the holder 60 will be described. The holder 60 is a resin molded product, and as shown in FIG. 1, it 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 line portion 21 + branch line portion 22) and a second circuit body 20B (main line portion 21 + branch line portion 22) of the circuit body 20 are placed.

[0039] Specifically, each of the pair of circuit body holding portions 61 extending in the front-rear direction is composed of a plurality of divided bodies (not shown) arranged side by side in the front-rear direction and an expansion and contraction portion (not shown) that connects the divided bodies adjacent in the front-rear direction in the front-rear direction. Each expansion and contraction 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 holding portions 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 holding portion 61 (see FIG. 3).

[0040] For each of the pair of left and right circuit body holding portions 61, a bus bar holding portion 64 (see FIG. 1) is integrally provided adjacent to the outside in the left-right direction for 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 pair of left and right circuit body holding portions 61, a plurality of bus bar holding portions 64 are arranged side by side in the front-rear direction. Since each bus bar holding portion 64 is provided on the corresponding divided body, the interval in the front-rear direction between the bus bar holding portions 64 adjacent in the front-rear direction can be varied by the function of the expansion and contraction portion.

[0041] Each bus bar holding portion 64 houses a corresponding bus bar 40. When the holder 60 is attached to the battery assembly 1, the bus bar 40 housed in each bus bar holding portion 64 is conductively connected to the corresponding positive electrode 4 and negative electrode 5 adjacent to each other in the front-rear direction on the upper surface of the battery assembly 1.

[0042] 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 pair of left and right circuit body holding portions 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). For this reason, as shown in FIG. 1, the cover 70 has a strip-like shape that extends long in the front-rear direction.

[0043] In the state where the bus bar module 10 is attached to the battery assembly 1, in the battery assembly 1, the plurality of stacked single cells 2 are electrically connected in series via the 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 the corresponding branch line portion 22, a wiring pattern 26 extending from the corresponding branch line portion 22 (contact portion 24), and a connector 29 mounted on the 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 for some reason an excessive current exceeding the rated current flows through the electronic component 50, 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, the inflow of the excessive current into the voltage detection device is prevented, so that the voltage detection device can be protected.

[0044] In the state of use of the battery assembly 1 to which the bus bar module 10 is attached, each single battery 2 constituting the battery assembly 1 expands and contracts in the stacking direction (front-rear direction) due to the operating heat associated with charging and discharging, the temperature of the external environment, etc. 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 batteries 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).

[0045] In this regard, in the bus bar module 10, even if expansion and contraction of the battery assembly 1 in the stacking direction (front-rear direction) due to thermal deformation of each single battery 2 and manufacturing variations of the battery assembly 1 occur, each of the plurality of expansion and contraction parts of the holder 60 expands and contracts in the front-rear direction, and each branch line part 22 made of a flexible substrate easily bends, so that the expansion and contraction and manufacturing variations due to thermal deformation of the battery assembly 1 can be easily absorbed.

[0046] <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) composed of flexible substrates are arranged such that the wiring patterns 26 of the first circuit body 20A and the second circuit body 20B are electrically connected and integrated at the overlapping portion (circuit connection portions 23) between the main line portions 21 of the first circuit body 20A and the main line portions 21 of the second circuit body 20B. 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. Therefore, 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 batteries 2. Similarly, by bending the branch lines or the like, variations in the size of the battery assembly 1 in the stacking direction (front-rear direction) due to the assembly tolerance of the single batteries 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, generally, even when a flexible substrate encloses a large number of circuit structures, it is more easily deformed flexibly with a much smaller force than the electric wires used in the conventional bus bar modules described above. Therefore, the assemblability to the battery assembly 1 is improved. Accordingly, the bus bar module 10 according to the present embodiment is superior in assemblability to the battery assembly 1 and in followability to deformation and manufacturing variations of the battery assembly 1 compared to the conventional bus bar modules described above.

[0047] Furthermore, 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 constituted by a single-piece 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 (universal) mounting device, after properly mounting the electronic component 50 to the branch line portion 22 using a general (universal) 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.

[0048] Furthermore, according to the bus bar module 10 according to the present embodiment, since the first circuit body 20A and the second circuit body 20B are prepared as separate bodies and then electrically connected, when the bus bar module 10 is flooded with water or the like, there is a risk that liquid such as water may enter the overlapping portion 23 (the gap between the circuit connection portions 23 of the first circuit body 20A and the second circuit body) of the main line portions 21 of the first circuit body 20A and the second circuit body. However, by applying the coating material 32 to the edge portions 23a of the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B so as to close the gap between the circuit connection portions 23 of the first circuit body 20A and the second circuit body 20B, the intrusion of liquid into the gap between the circuit connection portions 23 can be suppressed. Thereby, the bus bar module 10 can suppress the occurrence of a problem that the adjacent contact portions 25 are electrically connected (short-circuited) by liquid.

[0049] <Second Embodiment> Hereinafter, the bus bar module 110 according to the second embodiment of the present invention will be described with reference to the drawings. The bus bar module 110 according to the present embodiment is used, for example, to be assembled to a long battery assembly 101 (see FIG. 7, a battery module in which a plurality of single cells are stacked) as a driving power source mounted on an electric vehicle.

[0050] Hereinafter, for convenience of explanation, as shown in FIG. 6 and the like, “front”, “rear”, “left”, “right”, “upper” and “lower” are defined. The “front-rear direction”, “left-right direction” and “upper-lower direction” are orthogonal to each other. The front-rear direction coincides with the stacking direction of the plurality of single cells 102 constituting the battery assembly 101 (see FIGS. 6 and 7). Note that these directions are defined for convenience of explanation and do not necessarily correspond to the front-rear direction, left-right direction, and upper-lower direction of the vehicle when the bus bar module 110 is mounted on the vehicle.

[0051] First, as a preparation for explaining the bus bar module 110, the battery assembly 101 to which the bus bar module 110 is attached will be described with reference to FIG. 7. As shown in FIG. 7, the battery assembly 101 is configured by stacking a plurality of rectangular flat plate-shaped single cells 102 extending in the vertical direction and the horizontal direction in the front-rear direction. Each of the plurality of single cells 102 includes a rectangular flat plate-shaped battery body 3, a positive electrode 104 and a negative electrode 105 protruding upward from both left and right ends in the horizontal direction of the upper surface 106 of the battery body 103.

[0052] In the battery assembly 101, the plurality of single cells 102 are stacked such that the horizontal positions of the positive electrodes 104 and negative electrodes 105 of the single cells 102 adjacent to each other in the front-rear direction are reversed from each other, so that the positive electrodes 104 and negative electrodes 105 are alternately arranged in the front-rear direction at each of the left end portion and the right end portion of the upper surface of the battery assembly 101.

[0053] Hereinafter, the bus bar module 110 will be described. As shown in FIGS. 6, 8, and 9, the bus bar module 110 includes a long circuit body 120 extending in the front-rear direction (see FIGS. 6 and 8), a plurality of bus bars 140 (see FIG. 6) respectively connected to a plurality of branch line portions 122 (see FIG. 8) of the circuit body 120, a plurality of electronic components 150 (see FIG. 8) respectively mounted on the plurality of branch line portions 122, a holder 160 (see FIGS. 6 and 8) for holding the circuit body 120 and the bus bars 140, and a cover 170 (see FIG. 6) for covering the circuit body 120. Note that the main line portion 121 and the branch line portion 122 (see FIG. 8) of the circuit body 120 are also called “main trunk line” and “branch line”, respectively.

[0054] The circuit body 120 is composed of a flexible printed circuit (FPC) that can be easily bent. As can be understood from FIGS. 6 and 8, it includes a pair of left and right first circuit bodies 120A that are spaced apart in the left-right direction and extend in the front-back direction, and a pair of left and right second circuit bodies 120B that are respectively connected to the rear sides of the pair of left and right first circuit bodies 120A and extend in the front-back direction. Either one of the pair of left and right first circuit bodies 120A and the pair of left and right second circuit bodies 120B is connected in the left-right direction by a connecting portion 128 (see FIG. 6). A connector 129 (see FIG. 6) that is electrically connected to an external voltage detection device (not shown) or the like is mounted on the lower surface of the connecting portion 128.

[0055] Each of the first circuit body 120A and the second circuit body 120B includes a strip-shaped main line portion 121 that extends in the front-back direction, and at least one (in this example, a plurality of) branch line portions 122 that extend outward in the left-right direction from at least one (in this example, a plurality of) location in the front-back direction of the main line portion 121 (see FIG. 8). In this example, each branch line portion 122 extends from the main line portion 121 so as to have a U-shaped curved shape. Since the branch line portion 122 has a U-shaped curved shape, the flexibility of the branch line portion 122 in the front-back, left-right, and up-down directions is enhanced. A metal contact portion 124 is provided on the upper surface of the tip of each branch line portion 122 so as to be exposed to the outside (see FIG. 8).

[0056] By connecting the circuit connection portion 123 provided at the rear end portion of the main line portion 121 of the first circuit body 120A and the circuit connection portion 123 provided at the front end portion of the main line portion 121 of the second circuit body 120B, a circuit body 120 is configured in which the main line portions 121 of the first circuit body 120A and the second circuit body 120B are continuous and extend in a row in the front-back direction. The detailed structure of each circuit connection portion 123 of the first circuit body 120A and the second circuit body 120B and the connection procedure between the circuit connection portions 123 will be described later.

[0057] Each of the first circuit body 120A and the second circuit body 120B has its entire surface composed of a resin layer except for the locations where the contact portions 124 provided on the branch portions 122 are exposed (see FIG. 8) and the locations where the contact portions 125 (to be described later) provided on the circuit connection portions 123 are exposed (see FIG. 8), and encloses a plurality of wiring patterns 126 (see FIG. 8). Each wiring pattern 126 is a copper conductor extending in a strip shape and extends along the main line portion 121 and the branch line portion 122. Each of the first circuit body 120A and the second circuit body 120B 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 120A and the second circuit body 120B, a plurality of wiring patterns 126 are arranged in the single wiring layer. However, each of the first circuit body 120A and the second circuit body 120B may be a "double-sided FPC".

[0058] At the location where the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B are connected to each other, at least one (six in this example) wiring pattern 26 belonging to the first circuit body 120A and at least one (six in this example) wiring pattern 126 belonging to the second circuit body 120B are connected to each other one-to-one independently (see FIG. 8. Details will be described later).

[0059] The plurality of wiring patterns 126 included in the first circuit body 120A and the second circuit body 120B are each individually electrically connected to the connector 129 mounted on the connecting portion 128 through the insides of the corresponding branch line portion 122, main line portion 121, and connecting portion 128 in this order from the contact portion 124 of the corresponding branch line portion 122. Thereby, the contact portions 124 of each branch line portion 122 belonging to the first circuit body 120A and the second circuit body 120B are individually conductively connected to an external voltage detection device through the connector 129 mounted on the connecting portion 128.

[0060] At the tip of each branch portion 122, an electronic component 150 is mounted, and an elongated flat plate-shaped metal connection terminal 141 connected to the bus bar 140 is connected (see FIG. 8 etc.). The connection terminal 141 may be a part of a substantially rectangular flat plate-shaped metal bus bar 140 (see FIG. 6), or may be a member separate from the bus bar 140 and joined to the bus bar 140 by soldering or the like. The electronic component 150 is typically a chip fuse. The electronic component 150 is mounted on the tip of the branch portion 122 by soldering or the like so as to connect the contact portion 124 of the branch portion 122 and the connection terminal 141. Thereby, for each branch portion 122, the contact portion 124 (that is, the wiring pattern 126 extending from the contact portion 124) and the connection terminal 141 (that is, the bus bar 140) are electrically connected via the electronic component 150.

[0061] The mounting of such an electronic component 150 on the branch portion 122 is performed individually on the branch portion 122 belonging to the first circuit body 120A and the branch portion 122 belonging to the second circuit body 120B in a state before the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B are connected (that is, in a state where each of the first circuit body 120A and the second circuit body 120B is in a single state). Therefore, compared with the case where the first circuit body 120A and the second circuit body 120B are constituted by a common (single) flexible substrate, since the length of each of the first circuit body 120A and the second circuit body 120B in the front-rear direction becomes shorter, a large mounting device is not required. In other words, because the first circuit body 120A and the second circuit body 120B are separate bodies, regardless of the length and size of the long circuit body 120 obtained by connecting the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B, the electronic component 150 can be properly mounted on each branch portion 122, and the manufacturing cost of the bus bar module 110 can be reduced.

[0062] Next, the detailed structure of each circuit connection part 123 of the first circuit body 120A and the second circuit body 120B, and the connection procedure between the circuit connection parts 123 will be described. As shown in FIG. 8, on the upper surface of the circuit connection part 123 of the first circuit body 120A, a plurality (six in this example) of metal contact parts (pads) 125 are provided so as to be arranged at intervals in the front-rear direction and to be exposed to the outside. Wiring patterns 126 extend individually from each contact part 125. More specifically, for each of the three contact parts 125 on the front side (the base end side of the circuit connection part 123) among the six contact parts 125, the wiring pattern 126 extends from the contact part 125 to one side (left side) in the width direction (left-right direction) of the main line part 121 of the first circuit body 120A, and then extends forward. For each of the three contact parts 125 on the rear side (the tip end side of the circuit connection part 123) among the six contact parts 125, the wiring pattern 126 extends from the contact part 125 to the other side (right side) in the width direction (left-right direction) of the main line part 121 of the first circuit body 120A, and then extends forward.

[0063] In this way, by dispersing and arranging the extending parts of the plurality of wiring patterns 126 extending from the plurality of contact parts 125 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 parts of the wiring patterns 126 extending from the contact parts 125, miniaturization of the circuit connection part 123 (that is, the first circuit body 120A), and the like. On the upper surface of the circuit connection part 123 of the first circuit body 120A, a metal dummy contact part (land) 127 is provided at one place that does not interfere with the contact part 125 and the wiring pattern 126 so as to be exposed to the outside. The dummy contact part 127 is not connected (electrically connected) to the wiring pattern 126 (that is, the bus bar 140). In the circuit connection part 123 of the first circuit body 120A, through holes 131 penetrating in the thickness direction (up-down direction) of the circuit connection part 123 are formed at a plurality of places (two in this example) that do not interfere with the contact part 125, the wiring pattern 126, and the dummy contact part 127.

[0064] On the lower surface of the circuit connection portion 123 of the second circuit body 120B, a plurality (six in this example) of metal contact portions (pads) 125 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 125 of the first circuit body 120A. Wiring patterns 126 extend individually from each contact portion 125. More specifically, for each of the three contact portions 125 on the front side (the tip side of the circuit connection portion 123) among the six contact portions 125, the wiring pattern 126 extends from the contact portion 125 to the other side (right side) in the width direction (left-right direction) of the main line portion 121 of the second circuit body 120B, and then extends rearward. For each of the three contact portions 125 on the rear side (the base end side of the circuit connection portion 123) among the six contact portions 125, the wiring pattern 126 extends from the contact portion 125 to one side (left side) in the width direction (left-right direction) of the main line portion 121 of the second circuit body 120B, and then extends rearward.

[0065] In this way, by dispersing and arranging the extending portions of the plurality of wiring patterns 126 extending from the plurality of contact portions 125 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 126 extending from the contact portions 125, miniaturization of the circuit connection portion 123 (that is, the second circuit body 120B), etc. On the lower surface of the circuit connection portion 123 of the second circuit body 120B, a metal dummy contact portion (land) 127 is provided at a position that does not interfere with the contact portions 125 and the wiring patterns 126, corresponding to the dummy contact portion 127 of the first circuit body 120A, so as to be exposed to the outside. The dummy contact portion 127 is not connected (electrically connected) to the wiring pattern 126 (that is, the bus bar 140). In the circuit connection portion 123 of the second circuit body 120B, corresponding to the plurality of hole portions 131 of the first circuit body 120A, hole portions 131 penetrating in the thickness direction (up-down direction) of the circuit connection portion 123 are formed at a plurality of positions (two in this example) that do not interfere with the contact portions 125, the wiring patterns 126, and the dummy contact portion 127.

[0066] For the connection work between the circuit connection parts 123 of the first circuit body 120A and the second circuit body 120B, first, with the circuit connection part 123 of the first circuit body 120A arranged below the circuit connection part 123 of the second circuit body 120B, a plurality of contact parts 125 of the first circuit body 120A and a plurality of contact parts 125 of the second circuit body 120B are soldered one-to-one independently of each other, and the dummy contact part 127 of the first circuit body 120A and the dummy contact part 127 of the second circuit body 120B are soldered. These soldering operations can typically be performed by the so-called pulse heat method, in which a paste-like solder is sandwiched between the opposing contact parts 125 and the opposing dummy contact parts 127 in the vertical direction, and then a heater chip that can heat the solder to a meltable temperature is pressed against the soldering location and the heater chip is heated for 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 123 of the first circuit body 120A and the second circuit body 120B may be performed using a conductive adhesive instead of the above-described soldering.

[0067] As a result, at the location where the circuit connection parts 123 of the first circuit body 120A and the second circuit body 120B are connected, a plurality of wiring patterns 126 belonging to the first circuit body 120A and a plurality of wiring patterns 126 belonging to the second circuit body 120B are electrically connected one-to-one independently of each other and are also mechanically integrated. Further, the dummy contact part 127 of the first circuit body 120A and the dummy contact part 127 of the second circuit body 120B are mechanically integrated using solder, a conductive adhesive, or the like. Thereby, the first circuit body 120A and the second circuit body 120B can be more firmly integrated.

[0068] Next, tapes 132 are respectively arranged below the first circuit body 120A and above the second circuit body 120B, and the tapes 132 are attached to the outer surfaces of the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B so as to cover the edge portions 123a of the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B. Thereby, the gap between the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B is covered by the tape 132, and the intrusion of liquid such as water between the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B can be suppressed. That is, it is possible to suppress the occurrence of a problem in which the adjacent contact portions 125 are electrically connected (short-circuited) by the liquid by the tape 132. Note that the tape 132 is, for example, a known waterproof tape, protective tape, or the like.

[0069] Next, the plurality of protrusions 161a are inserted into the plurality of hole portions 132a of the lower tape 132, the plurality of hole portions 131 of the first circuit body 120A, the plurality of hole portions 131 of the second circuit body 120B, and the plurality of hole portions 132a of the upper tape 132 in this order from above (see FIG. 8). Thereby, with the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B connected to each other, the first circuit body 120A and the second circuit body 120B are housed in the holder 160 (circuit body holding portion 161). When an unintended external force is applied to the circuit body 120 after connection (more specifically, the main wire portions 121 of the first circuit body 120A and the second circuit body 120B), by receiving the external force with the protrusions 161a, it is possible to suppress the external force from reaching the connection portion of the two contact portions 125 (wiring patterns 126). Therefore, the reliability of the electrical connection between the first circuit body 120A and the second circuit body 120B can be improved.

[0070] Next, the holder 160 will be described. The holder 160 is a resin molded product, and as shown in FIG. 6, it integrally includes a pair of left and right strip-shaped circuit body holding portions 161 that extend in the front-rear direction with a space in the left-right direction, and a plurality of connecting portions 162 that connect the pair of left and right circuit body holding portions 161 in the left-right direction at a plurality of positions in the front-rear direction. The pair of left and right circuit body holding portions 161 are mounted with a pair of left and right first circuit bodies 120A (main wire portion 121 + branch wire portion 122) and a second circuit body 120B (main wire portion 121 + branch wire portion 122) of the circuit body 120.

[0071] Each of the pair of circuit body holding portions 161 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 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 holding portions 161 are configured to be telescopically expandable along the front-rear direction. As described above, a plurality (two) of protrusions 161a are provided on the bottom wall of each circuit body holding portion 161 (see FIG. 8).

[0072] For each of the pair of left and right circuit body holding portions 161, a bus bar holding portion 164 (see FIG. 6) 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 pair of left and right circuit body holding portions 161, a plurality of bus bar holding portions 164 are arranged side by side in the front-rear direction. Since each bus bar holding portion 164 is provided on the corresponding divided body, the distance in the front-rear direction between adjacent bus bar holding portions 164 in the front-rear direction can be varied by the function of the telescopic portion.

[0073] Each bus bar holding portion 164 houses the corresponding bus bar 140. When the holder 160 is attached to the battery assembly 101, the bus bar 140 housed in each bus bar holding portion 164 is conductively connected to the corresponding positive electrode 104 and negative electrode 105 adjacent to each other in the front-rear direction on the upper surface of the battery assembly 101.

[0074] Next, the cover 170 will be described. The cover 170, which is a resin molded product, functions to cover the circuit bodies 120 placed on the pair of left and right circuit body holding portions 161 that are long in the front-rear direction of the holder 160, that is, the first circuit body 120A (main line portion 121 + branch line portion 122) and the second circuit body 120B (main line portion 121 + branch line portion 122) (see FIG. 6). Therefore, as shown in FIG. 6, the cover 170 has a strip-like shape that extends long in the front-rear direction.

[0075] In the state where the bus bar module 110 is attached to the battery assembly 101, in the battery assembly 101, a plurality of stacked single cells 102 are electrically connected in series via a plurality of bus bars 140. Further, each bus bar 140 is conductively connected to an external voltage detection device through an electronic component 150 mounted on the corresponding branch portion 122, a wiring pattern 126 extending from the corresponding branch portion 122 (contact portion 124), and a connector 129 mounted on the connecting portion 128 in this order. Thereby, the voltage (potential) of each bus bar 140 can be individually detected by an external voltage detection device. When an excessive current exceeding the rated current flows through the electronic component 150 for some reason, the electrical connection between the bus bar 140 and the wiring pattern 126 is cut off by the electronic component 150 by exerting the fuse function of the electronic component 150. Thereby, since the inflow of excessive current into the voltage detection device is prevented, the voltage detection device can be protected.

[0076] In the usage state of the battery assembly 101 to which the bus bar module 110 is attached, each single cell 102 constituting the battery assembly 101 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, etc. As a result, the battery assembly 101 also deforms so as to expand and contract in the stacking direction (front-rear direction). Also, due to the assembly tolerance when stacking and arranging a plurality of single cells 102, generally, the size of the battery assembly 101 in the stacking direction (front-rear direction) may differ for each manufactured battery assembly 101 (manufacturing variations may occur).

[0077] In this regard, in the bus bar module 110, even when expansion and contraction of the battery assembly 101 in the stacking direction (front-rear direction) and manufacturing variations of the battery assembly 101 occur due to thermal deformation of each single cell 2, each of the plurality of expansion and contraction portions of the holder 160 expands and contracts in the front-rear direction, and each branch portion 122 made of a flexible substrate easily bends, so that the expansion and contraction and manufacturing variations due to thermal deformation of the battery assembly 101 can be easily absorbed.

[0078] <Function and Effect> As described above, according to the bus bar module 110 according to the present embodiment, the first circuit body 120A and the second circuit body 120B (main line) formed of a flexible substrate are electrically connected to each other at the overlapping portion (circuit connection portions 123) between the main line portion 121 of the first circuit body 120A and the main line portion 121 of the second circuit body 120B, and are integrated. In other words, the first circuit body 120A and the second circuit body 120B are electrically connected. Further, branch lines 122 (branch lines) extend from the main line portions 121 of the first circuit body 120A and the second circuit body 120B so as to branch. Therefore, when the battery assembly 101 expands and contracts in the stacking direction (front-rear direction) due to thermal deformation of each single battery 102, the branch lines are bent or the like, so that each bus bar 140 can move in the stacking direction of the single battery 102. Similarly, by bending the branch lines or the like, variations in the size of the battery assembly 101 in the stacking direction (front-rear direction) due to the assembly tolerance of the single battery 102 can be absorbed. In other words, the bus bar module 110 according to the present embodiment can easily cope with the expansion and contraction of the battery assembly 101 and manufacturing variations by deforming the branch lines. Here, generally, even when a flexible substrate includes a large number of circuit structures, it is more easily deformed flexibly with a much smaller force than the electric wires used in the conventional bus bar modules described above. Therefore, the assemblability to the battery assembly 101 is improved. Accordingly, the bus bar module 110 according to the present embodiment is superior in assemblability to the battery assembly 101 and followability to deformation and manufacturing variations of the battery assembly 101 as compared with the conventional bus bar modules described above.

[0079] Furthermore, the first circuit body 120A and the second circuit body 120B are prepared as separate bodies and then electrically connected. Therefore, compared with the case where the first circuit body 120A and the second circuit body 120B are formed of a single flexible substrate, the lengths of the first circuit body 120A and the second circuit body 120B in the stacking direction (front-rear direction) are shortened. Therefore, when attaching (i.e., mounting) the electronic component 150 to each branch line portion 122, 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 120A and the second circuit body 120B are connected are not suitable for a general (universal) mounting device, after appropriately mounting the electronic component 150 to the branch line portion 122 using a general (universal) mounting device for each of the first circuit body 120A and the second circuit body 120B, the first circuit body 120A and the second circuit body 120B may be connected, so that the manufacturing cost of the bus bar module 110 can be reduced.

[0080] Furthermore, according to the bus bar module 110 according to the present embodiment, since the first circuit body 120A and the second circuit body 120B are prepared as separate bodies and then electrically connected, when the bus bar module 110 is flooded with water or the like, there is a risk that liquid such as water may enter the overlapping portion 123 of the main line portions 121 of the first circuit body 120A and the second circuit body (the gap between the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B). However, by attaching the tape 132 to the outer surfaces of the first circuit body 120A and the second circuit body 120B so as to cover the edge portions 123a of the circuit connection portions 123 of the first circuit body 120A and the second circuit body 120B, the intrusion of liquid into the gap between the circuit connection portions 123 can be suppressed. Thereby, the bus bar module 110 can suppress the occurrence of a problem in which the adjacent contact portions 125 are electrically connected (short-circuited) by liquid.

[0081] <Other embodiments> Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. can be made as appropriate. In addition, the materials, shapes, dimensions, numbers, arrangement locations, etc. of the respective components in the above-described embodiments are arbitrary as long as the present invention can be achieved, and are not limited.

[0082] Here, the features of the embodiment of the bus bar module according to the present invention described above are briefly summarized and listed below in [1] to [3] respectively.

[0083] [1] A bus bar module (10, 110) attached to a battery assembly (1, 101) in which a plurality of single cells (2) are stacked, A first circuit body (20A, 120A) composed of a flexible substrate having a first wiring pattern (26, 126), and a first main line portion (21, 121) arranged to extend along the stacking direction of the plurality of single cells (2, 102), and a first branch line portion (22, 122) extending so as to branch from the first main line portion (21, 121); A second circuit body (20B, 120B) composed of a flexible substrate having a second wiring pattern (26, 126), and a second main line portion (21, 121) arranged to extend along the stacking direction, and a second branch line portion (22, 122) extending so as to branch from the second main line portion (21, 121); A bus bar (40, 140) to be connected to each electrode (4, 5, 104, 105) of the plurality of single cells (2, 102); An electronic component (50, 150) attached to the first branch line portion (22, 122) and the second branch line portion (22, 122) so as to connect the first wiring pattern (26, 126) and the bus bar (40, 140) corresponding to the second wiring pattern (26, 126); A holder (60, 160) that is stretchable and contractible along the stacking direction and holds the first circuit body (20A, 120A), the second circuit body (20B, 120B), and the bus bar (40, 140); The first wiring pattern (26, 126) has a plurality of first contact portions (25, 125) arranged in the stacking direction; The second wiring pattern (26, 126) has a plurality of second contact portions (25, 125) arranged in the stacking direction; In the overlapping portion (23, 123) of the first bus bar portion (21, 121) and the second bus bar portion (21, 121), the plurality of first contact portions (25, 125) and the plurality of second contact portions (25, 125) are electrically connected to each other. Further provided is a waterproof portion (coating material 32, tape 132) for sealing the overlapping portion in a watertight manner. Bus bar module (110).

[0084] According to the bus bar module having the configuration of [1] above, a first circuit body and a second circuit body (hereinafter also referred to as "main lines") each composed of a flexible substrate are integrated by electrically connecting a first contact portion of a first wiring pattern and a second contact portion of a second wiring pattern in an overlapping portion of a first bus bar portion of the first circuit body and a second bus bar portion of the second circuit body. In other words, the first circuit body and the second circuit body are electrically connected. Further, a first branch portion and a second branch portion (hereinafter also referred to as "branch lines") extend so as to branch from the first bus bar portion and the second bus bar 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 bend or the like, so that each bus bar can move in the stacking direction of the single battery. Similarly, by bending or the like of the branch lines, 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 a flexible substrate encloses a large number of circuit structures, it is much easier to deform flexibly with a much smaller force than the electric wires used in the conventional bus bar modules 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 compared to the conventional bus bar modules described above.

[0085] 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 separately. 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-purpose (off-the-shelf) mounting device, after appropriately mounting the electronic components on the branch circuit bodies using a general-purpose (off-the-shelf) 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.

[0086] Furthermore, according to the bus bar module with the above configuration, since the first circuit body and the second circuit body are electrically connected after being prepared separately, when the bus bar module is flooded with water or the like, there is a risk that liquid such as water may enter the overlapping portion (between the first main line portion and the second main line portion) of the first main line portion of the first circuit body and the second main line portion of the second circuit body. However, by providing a waterproof portion in which the bus bar module seals the overlapping portion in a watertight manner, it is possible to suppress the occurrence of a problem in which adjacent connection portions are electrically connected (short-circuited) by a liquid.

[0087] [2] In the bus bar module (10) described in the above [1], the waterproof portion is a coating material (32) applied so as to close at least a part of the gap in the edge portion (23a) of the overlapping portion, bus bar module (10).

[0088] According to the bus bar module with the configuration of the above [2], by applying the coating material so as to close at least a part of the gap in the edge portion of the overlapping portion of the first circuit body and the second circuit body, it is possible to suppress the intrusion of liquid into the gap.

[0089] [3] In the bus bar module (110) described in [1] above, the waterproof portion is a tape (132) attached to the outer surface of the overlapping portion so as to cover the edge portion (123a) of the overlapping portion. Bus bar module (110).

[0090] According to the bus bar module having the configuration of [3] above, by attaching a tape to the outer surface of the overlapping portion so as to cover the edge portion in the overlapping portion of the first circuit body and the second circuit body, it is possible to suppress the intrusion of liquid into the gap in the overlapping portion.

Explanation of reference numerals

[0091] 1,101 Battery assembly 2,102 Single battery 4,104 Positive electrode (electrode) 5,105 Negative electrode (electrode) 10,110 Bus bar module 20A,120A First circuit body 20B,120B Second circuit body 21,121 Main wire portion (first main wire portion, second main wire portion) 22,122 Branch wire portion (first branch wire portion, second branch wire portion) 23,123 Circuit connection portion (overlapping portion) 23a,123a Edge portion 25,125 Contact portion (first contact portion, second contact portion) 26,126 Wiring pattern (first wiring pattern, second wiring pattern) 31,131 Hole portion (first hole portion, second hole portion) 32 Coating material (waterproof portion) 132 Tape (waterproof portion) 40,140 Bus bar 50,150 Electronic component 60,160 Holder 61a,161a Protrusion

Claims

1. A bus bar module attached to a battery assembly in which a plurality of single cells are stacked, Composed of a flexible substrate having a first wiring pattern, 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 first circuit body having; Composed of a flexible substrate having a second wiring pattern, 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 second circuit body having; 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; The first wiring pattern has a plurality of first contact portions arranged in the stacking direction; The second wiring pattern has a plurality of second contact portions arranged in the stacking direction; In an overlapping portion between the first main line portion and the second main line portion, the plurality of first contact portions and the plurality of second contact portions are electrically connected to each other; Further comprising a waterproof portion that seals the overlapping portion in a watertight manner; Bus bar module.

2. In the bus bar module according to claim 1, The waterproof portion is A coating material applied so as to block at least a part of the gap at the edge portion of the overlapping portion; Bus bar module.

3. In the bus bar module according to claim 1, The waterproof portion is A tape attached to the outer surface of the overlapping portion so as to cover the edge portion of the overlapping portion; Bus bar module.

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