Conductive Module

Abstract

To suppress an increase in size and improve yield. [Solution] The device comprises a bus bar (10) that physically and electrically connects to the electrode terminals (BCb) of the battery cells (BC), a flexible printed circuit board (20) formed in a rectangular shape extending in the arrangement direction of the multiple battery cells and electrically connecting the battery monitoring unit and the bus bar, and a flexible electric wire (30) for each bus bar that electrically connects the bus bar to the flexible printed circuit board, the flexible printed circuit board having circuit conductors for each bus bar that electrically connect the bus bar to the battery monitoring unit, and a pad portion (21) for each bus bar that is arranged adjacent to the bus bar and electrically connected to the circuit conductor for that bus bar, and one end of the electric wire is physically and electrically connected to an electric wire connection portion (41) on the bus bar side, and the other end is physically and electrically connected to the pad portion for that bus bar.

Description

[Technical Field]

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

[0002] A conductive module is a wiring module that electrically connects a battery module, which includes an array of multiple battery cells, to a battery monitoring unit that monitors the battery cell status. This conductive module includes bus bars that physically and electrically connect the electrode terminals of one or a pair of battery cells in the battery module, and a flexible printed circuit board that electrically connects the multiple bus bars to the battery monitoring unit. In a battery module, the pitch between the electrode terminals of adjacent battery cells can vary within the design tolerance due to thermal expansion and contraction of the battery cells, manufacturing tolerance variations of the battery cells, and assembly tolerance variations of the multiple battery cells. In this case, the positions of the electrode terminals on the flexible printed circuit board in the battery module are shifted relative to each other within the design tolerance. Therefore, conventional conductive modules use a flexible printed circuit board with a trunk line and branch lines branching off from the trunk line at each bus bar. The branch lines are bent three-dimensionally, such as in an S shape, and connected to the bus bars to absorb the positional shift of the electrode terminals. This type of conductive module is disclosed, for example, in Patent Documents 1 and 2 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-205175 [Patent Document 2] Japanese Patent Publication No. 2022-173610 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional conductive modules use flexible printed circuit boards in which branch lines branch off from a rectangular, flat trunk line for each bus bar, which leads to a decrease in yield when manufacturing multiple flexible printed circuit boards from a single sheet. Furthermore, in conventional conductive modules, the branch lines extending from the trunk line are formed into three-dimensional shapes and connected to the bus bars, which requires not only installation space for the branch lines connecting the trunk line and bus bars but also space for the branch lines to fulfill their tolerance absorption function, potentially resulting in an increase in the module's size.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a conductive module that is suppressed from becoming large in size and that can be manufactured with a high yield. [Means for solving the problem]

[0006] The present invention comprises a bus bar that physically and electrically connects to the electrode terminals of one or a pair of battery cells in a battery module in which a plurality of battery cells are arranged; a flexible printed circuit board that is formed in a rectangular shape extending in the arrangement direction of the plurality of battery cells and that electrically connects the bus bar to a battery monitoring unit that monitors the battery states of the battery cells; and a flexible electric wire for each bus bar that electrically connects the bus bar to the flexible printed circuit board, wherein the flexible printed circuit board comprises circuit conductors for each bus bar that electrically connect the bus bar to the battery monitoring unit, and pad portions for each bus bar that are arranged adjacent to the bus bar and electrically connected to the circuit conductors for that bus bar, and wherein one end of the electric wire is physically and electrically connected to the electric wire connection portion on the bus bar side and the other end is physically and electrically connected to the pad portion for that bus bar. [Effects of the Invention]

[0007] In the conductive module according to the present invention, the tolerance absorption function is performed by a flexible electric wire, so this tolerance absorption function does not have to be performed by each branch wire as in the past, and there is no need to provide space for the branch wire to perform the tolerance absorption function. Therefore, this conductive module can achieve the tolerance absorption function without increasing the size. Furthermore, in the conductive module according to the present invention, the flexible printed circuit board is formed into a rectangular flat plate, which improves the yield when manufacturing multiple flexible printed circuit boards from a single sheet. In this way, the conductive module according to the present invention can achieve the tolerance absorption function while improving the yield and reducing the size. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a conductive module according to an embodiment. [Figure 2] FIG. 2 is a plan view showing the conductive module of the embodiment. [Figure 3] FIG. 3 is a plan view of the conductive module of the embodiment seen from a different angle. [Figure 4] FIG. 4 is an exploded perspective view showing the conductive module of the embodiment. [Figure 5] FIG. 5 is an explanatory diagram illustrating a conductive module in which misalignment occurs between the conductive module and the electrode terminal. [Figure 6] FIG. 6 is an explanatory diagram illustrating a conductive module in which misalignment occurs between the conductive module and the electrode terminal. [Figure 7] FIG. 7 is an explanatory diagram illustrating a conductive module in which misalignment occurs between the conductive module and the electrode terminal. [Figure 8] FIG. 8 is an explanatory diagram illustrating the yield of flexible printed circuit boards. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a conductive module according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this embodiment.

[0010] [Embodiment] One embodiment of a conductive module according to the present invention will be described with reference to FIGS.

[0011] Reference numeral 1 in FIGS. 1 to 7 indicates a conductive module of this embodiment. This conductive module 1 is assembled to a battery module BM ( FIGS. 1 and 4 ) in which a plurality of battery cells BC are arranged (e.g., arranged in a single row), and electrically connects the plurality of battery cells BC in the battery module BM. The conductive module 1 also electrically connects the battery module BM to a battery monitoring unit (not shown), allowing the battery monitoring unit to monitor the battery state (voltage, etc.) of the battery cells BC. The conductive module 1 and the battery module BM constitute a battery pack BP ( FIGS. 1 and 4 ). The battery pack BP is mounted, for example, on a vehicle (such as a battery electric vehicle (BEV) or hybrid electric vehicle (HEV)) equipped with a rotating machine as a drive source, and is used to supply power to the rotating machine. Note that the battery module BM in the figures is a portion of the plurality of battery cells BC.

[0012] Each battery cell BC includes a cell body BCa and positive and negative electrode terminals BCb (FIG. 4). The battery cell BC shown here has a cell body BCa formed in a rectangular shape with six outer wall surfaces. In the battery module BM, adjacent cell bodies BCa in the arrangement direction are arranged with one outer wall surface facing each other. This battery module BM includes one electrode terminal group BCc in which one electrode terminal BCb of each battery cell BC is arranged along the arrangement direction, and another electrode terminal group BCc in which the other electrode terminals BCb of each battery cell BC are arranged along the arrangement direction (FIG. 4).

[0013] Hereinafter, when the term "arrangement direction" is used without any particular mention, it refers to the arrangement direction of a plurality of battery cells BC or the arrangement direction of a plurality of electrode terminals BCb in an electrode terminal group BCc.

[0014] In this example, each battery cell BC has a positive and negative electrode terminal BCb on one of the six outer wall surfaces of the cell body BCa (FIG. 4). Therefore, in the battery module BM, two electrode terminal groups BCc are provided on one plane (FIG. 4).

[0015] The electrode terminal BCb shown here is formed in a flat plate shape and is physically and electrically connected to the bus bar 10 (described later) by welding or the like (FIG. 4). However, the electrode terminal BCb may be formed in a pole column shape with a male screw portion. In this case, the bus bar 10 is fixed to the electrode terminal BCb by screwing a female screw member into the male screw portion of the electrode terminal BCb.

[0016] The conductive module 1 includes a bus bar 10 that physically and electrically connects to the electrode terminals BCb of one or a pair of battery cells BC in the battery module BM (FIGS. 1 to 4).

[0017] The busbar 10 is made of a conductive material such as metal. The busbar 10 is a metal, plate-shaped conductive component, and is formed, for example, by press-molding a metal plate. The busbar 10 shown here is formed into a rectangular, flat plate and is physically and electrically connected to the electrode terminal BCb by laser welding.

[0018] The busbars 10 include one that is physically and electrically connected to one electrode terminal BCb that serves as a common negative electrode in the battery module BM, and another that is physically and electrically connected to one electrode terminal BCb that serves as a common positive electrode in the battery module BM. The busbars 10 also include busbars 10 that are physically and electrically connected to electrode terminals BCb that are adjacent to each other in the arrangement direction of a pair of battery cells BC in the battery module BM.

[0019] The conductive module 1 is formed in a rectangular shape extending in the arrangement direction, and includes a flexible printed circuit board (FPC) 20 that electrically connects the busbars 10 and the battery monitoring unit (FIGS. 1 to 4).

[0020] The flexible printed circuit board 20 includes circuit conductors (not shown) for each bus bar 10 that electrically connect the bus bar 10 to the battery monitoring unit. The circuit conductors in the flexible printed circuit board 20 are formed of a conductor pattern such as copper foil. The flexible printed circuit board 20 includes various films (base film and cover film) that are flexible and flat, as insulating coatings, and a conductor pattern is formed on at least one of the various films (the base film). The conductor pattern (circuit conductor) is enclosed by the insulating coating. Therefore, the flexible printed circuit board 20 includes pad portions 21 for each bus bar 10 that are adjacent to the bus bar 10 and electrically connected to the circuit conductors for the bus bar 10 as electrical contacts with the bus bar 10 ( FIGS. 1 and 2 ).

[0021] The conductive module 1 is flexible and includes electric wires 30 for each bus bar 10 that electrically connect the bus bar 10 to the flexible printed circuit board 20 (FIGS. 1 to 4). One end of each electric wire 30 is physically and electrically connected to an electric wire connection portion 41 on the bus bar 10 side, and the other end is physically and electrically connected to a pad portion 21 for that bus bar 10, thereby electrically connecting the bus bar 10 to the circuit conductor for that bus bar 10.

[0022] The electric wire 30 includes a core wire 31 and a covering 32 covering the core wire 31 (FIGS. 1 to 3). The electric wire 30 has a first exposed core wire portion 31a at one end where one end of the core wire 31 is exposed, and a second exposed core wire portion 31b at the other end where the other end of the core wire 31 is exposed (FIGS. 1 to 3).

[0023] The electric wire connection parts 41 are formed in a flat plate shape and protrude outside the battery module BM in a protruding direction perpendicular to the arrangement direction (Fig. 1). The flexible printed circuit board 20 has a width direction perpendicular to its own extension direction, and this width direction is aligned with the protruding direction of the electric wire connection parts 41, and is disposed adjacent to the battery module BM with one flat surface 20a of the flexible printed circuit board 20 placed on the same plane as one flat surface 41a of the electric wire connection parts 41 (Figs. 1 to 3). The flexible printed circuit board 20 is disposed with a gap between it and the electric wire connection parts 41 in the width direction.

[0024] The electric wire 30 is disposed between the electric wire connection portion 41 and the flexible printed circuit board 20, and electrically connects one flat surface 41a of the electric wire connection portion 41 to the pad portion 21 on one flat surface 20a of the flexible printed circuit board 20. The electric wire 30 is bent on the same plane as the electric wire connection portion 41 and one flat surface 41a, 20a of the flexible printed circuit board 20 (FIGS. 1 to 3). In addition, the first exposed core wire portion 31a at one end of the electric wire 30 is physically and electrically connected to one flat surface 41a of the electric wire connection portion 41, and the second exposed core wire portion 31b at the other end is physically and electrically connected to the pad portion 21 on one flat surface 20a of the flexible printed circuit board 20 (FIGS. 1 to 3). Here, the electric wire 30 is bent into a U-shape.

[0025] For example, the wire connection portion 41 shown here is provided as a part of a bus bar connection terminal 40 that physically and electrically connects to the bus bar 10 ( FIGS. 1 to 4 ). The bus bar connection terminal 40 has the wire connection portion 41 that physically and electrically connects the first exposed core portion 31 a at one end of the electric wire 30, and a bus bar connection portion 42 that physically and electrically connects to the bus bar 10 ( FIGS. 1 to 3 ). The bus bar connection terminal 40 is formed, for example, from a metal plate as a base material, into a flat plate shape that linearly connects the wire connection portion 41 and the bus bar connection portion 42. In this example, the bus bar connection terminal 40 is formed into a rectangular flat plate shape with the linear direction as the longitudinal direction, and the wire connection portion 41 protrudes out of the battery module BM along the longitudinal direction.

[0026] In this bus bar connection terminal 40, the bus bar connection portion 42 on the other plane is placed on the plane of the bus bar 10 with the longitudinal direction aligned in a direction perpendicular to the arrangement direction, and the bus bar connection portion 42 and the bus bar 10 are physically and electrically connected by, for example, laser welding. In this bus bar connection terminal 40, this causes the wire connection portion 41 to protrude outside the battery module BM in a direction perpendicular to the arrangement direction. In the wire connection portion 41, the first exposed core portion 31a at one end of the electric wire 30 is placed on one plane 41a, and this first exposed core portion 31a is physically and electrically connected by, for example, soldering. Then, the second exposed core portion 31b at the other end of the electric wire 30 is placed on the pad portion 21 on one plane 20a of the flexible printed circuit board 20, and this second exposed core portion 31b is physically and electrically connected to the pad portion 21 by, for example, soldering.

[0027] Incidentally, the electric wire connection portion 41 may be provided as a part of the bus bar 10 (not shown). In this case, the bus bar 10 is provided with a bus bar main body that is physically and electrically connected to the electrode terminal BCb by laser welding, and the electric wire connection portion 41 that protrudes from the bus bar main body.

[0028] As mentioned above, in the battery module BM, the position of the electrode terminal BCb may be misaligned relative to the flexible printed circuit board 20 within the range of design tolerance. In the conductive module 1 of the present embodiment, the battery module BM side, in which the bus bar 10 is connected to the electrode terminal BCb, and the flexible printed circuit board 20 are connected by a flexible electric wire 30, and therefore, the electric wire 30 can absorb the misalignment of the electrode terminal BCb.

[0029] Specifically, in the conductive module 1, if the electrode terminals BCb are displaced relative to the flexible printed circuit board 20 in one direction in the arrangement direction due to thermal expansion of the battery cells BC or the like, the shape of the wires 30 can be changed to accommodate the relative movement, thereby adapting to the positional displacement of the electrode terminals BCb ( FIG. 5 ). Note that in the conductive module 1, even if the electrode terminals BCb are displaced relative to the flexible printed circuit board 20 in the width direction of the flexible printed circuit board 20 due to thermal expansion of the battery cells BC or the like, the shape of the wires 30 can be changed to accommodate the relative movement, thereby adapting to the positional displacement of the electrode terminals BCb. The conductive module 1 in FIG. 5 shows a case in which the electrode terminals BCb are displaced relative to the flexible printed circuit board 20 in one direction in the arrangement direction and in the width direction of the flexible printed circuit board 20.

[0030] Furthermore, in this conductive module 1, if the electrode terminals BCb are displaced relative to the flexible printed circuit board 20 in the other direction in the arrangement direction due to thermal expansion of the battery cells BC or the like, the shape of the electric wires 30 can be changed in accordance with the relative movement to accommodate the displacement of the electrode terminals BCb (FIG. 6). The conductive module 1 in FIG. 6 shows a case in which the electrode terminals BCb are displaced relative to the flexible printed circuit board 20 in the other direction in the arrangement direction and in the width direction of the flexible printed circuit board 20.

[0031] Furthermore, in this conductive module 1, if the electrode terminal BCb is displaced relative to the flexible printed circuit board 20 in a direction perpendicular to the plane of the electrode terminal BCb due to thermal expansion of the battery cell BC or the like, the shape of the electric wire 30 can be changed to accommodate the relative movement, thereby adapting to the displacement of the electrode terminal BCb ( FIG. 7 ). FIG. 7 shows the movement of the electric wire 30 when the electrode terminal BCb is displaced in one direction in the perpendicular direction. Although not shown here, even when the electrode terminal BCb is displaced in the other direction in the perpendicular direction, the shape of the electric wire 30 can be changed to accommodate the relative movement of the electrode terminal BCb and the flexible printed circuit board 20 to adapt to the displacement of the electrode terminal BCb.

[0032] Furthermore, in this conductive module 1, even if the position of the electrode terminal BCb relative to the flexible printed circuit board 20 is misaligned in the arrangement direction due to manufacturing tolerance variations of the battery cells BC or assembly tolerance variations of the multiple battery cells BC, the shape of the electric wire 30 can be changed to match the misalignment of the electrode terminal BCb, thereby enabling accurate assembly to the battery module BM.

[0033] Furthermore, in this conductive module 1, even if the position of the electrode terminal BCb relative to the flexible printed circuit board 20 is misaligned in the width direction of the flexible printed circuit board 20 due to manufacturing tolerance variations of the battery cells BC or assembly tolerance variations of the multiple battery cells BC, the shape of the electric wire 30 can be changed to match the misalignment of the electrode terminal BCb, thereby enabling accurate assembly to the battery module BM.

[0034] 5 and 6, the positions of the electrode terminals BCb on the flexible printed circuit board 20 are misaligned relative to each other in the arrangement direction and the width direction of the flexible printed circuit board 20 due to variations in manufacturing tolerances of the battery cells BC and variations in assembly tolerances of the multiple battery cells BC. Even in such cases, in this conductive module 1, the shape of the electric wires 30 can be changed to accommodate the misalignment of the electrode terminals BCb, enabling accurate assembly to the battery module BM.

[0035] Furthermore, in this conductive module 1, even if the position of the electrode terminal BCb relative to the flexible printed circuit board 20 is misaligned in a direction perpendicular to the plane of the electrode terminal BCb due to variations in manufacturing tolerances of the battery cell BC or variations in assembly tolerances of multiple battery cells BC, the shape of the electric wire 30 can be changed to match the misalignment of the electrode terminal BCb, thereby enabling accurate assembly to the battery module BM (Figure 7).

[0036] As described above, the conductive module 1 of this embodiment assigns tolerance absorption in three mutually orthogonal directions to the flexible electric wire 30. This does not require each branch wire to perform this tolerance absorption function, as in the conventional case, and there is no need to provide space for the branch wire to perform the tolerance absorption function. Therefore, the conductive module 1 of this embodiment can achieve the tolerance absorption function without increasing its size. In particular, in the conductive module 1 shown here, the electric wire connection portion 41 and one of the flat surfaces 41a, 20a of the flexible printed circuit board 20 are arranged on the same plane, and the electric wire 30 is bent on the same plane as each of the flat surfaces 41a, 20a, thereby more effectively reducing the size of the module. Furthermore, in the conductive module 1 of this embodiment, the flexible printed circuit board 20 is molded into a rectangular plate shape, which improves the yield when multiple flexible printed circuit boards 20 are manufactured from a single sheet 20A (FIG. 8). As such, the conductive module 1 of this embodiment can achieve the tolerance absorption function without increasing its size and with improved yield. [Explanation of symbols]

[0037] 1 Conductive Module 10 Bus Bar 20 Flexible printed circuit board 20a One side 21 Pad section 30 Electric wire 40 Busbar connection terminal 41 Wire connection 41a One plane BC battery cell BCb electrode terminal BM battery module

Claims

1. a bus bar that physically and electrically connects to electrode terminals of one or a pair of battery cells in a battery module in which a plurality of battery cells are arranged; a flexible printed circuit board formed in a rectangular shape extending in the arrangement direction of the plurality of battery cells, and electrically connecting the bus bar and a battery monitoring unit that monitors the battery states of the battery cells; an electric wire for each bus bar that is flexible and electrically connects the bus bar to the flexible printed circuit board; Equipped with the flexible printed circuit board includes a circuit conductor for each bus bar that electrically connects the bus bar to the battery monitoring unit, and a pad portion for each bus bar that is disposed adjacent to the bus bar and electrically connected to the circuit conductor for that bus bar; The conductive module is characterized in that one end of the electric wire is physically and electrically connected to the electric wire connection portion on the bus bar side, and the other end is physically and electrically connected to the pad portion for that bus bar.

2. the electric wire connection portion is formed in a flat plate shape and protrudes outside the battery module in a protruding direction perpendicular to the arrangement direction; the flexible printed circuit board is disposed adjacent to the battery module with a width direction perpendicular to its extension direction, the width direction aligned with the protruding direction, and one of its flat surfaces being flush with one of the flat surfaces of the electric wire connection portion; 2. The conductive module according to claim 1, wherein the electric wire is bent on the same plane as the electric wire connection portion and one of the planes of the flexible printed circuit board, and the one end is physically and electrically connected to the one of the planes of the electric wire connection portion, and the other end is physically and electrically connected to the pad portion of the one of the planes of the flexible printed circuit board.

3. The conductive module according to claim 1 or 2, wherein the electric wire connection portion is provided as a part of the bus bar.

4. The conductive module according to claim 1 or 2, wherein the electric wire connection portion is provided as a part of a bus bar connection terminal that is physically and electrically connected to the bus bar.

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