Rechargeable battery module

Abstract

A rechargeable battery module is disclosed. The rechargeable battery module includes a bus bar holder covering a plurality of battery cells, a bus bar disposed on the bus bar holder to electrically connect the battery cells, and a flexible printed circuit (FPC) attached to the bus bar to transmit a signal and detect a current from the bus bar, the flexible printed circuit includes a thin copper film attached between inner surfaces of a pair of cover layers, in which the thin copper film is exposed as a unit film portion through a plurality of openings formed in the pair of cover layers, the thin copper film and the pair of cover layers are bent, and the unit film portion is formed in multiple layers and welded to a bus bar.

Description

Technical Field

[0001] The present disclosure relates to a rechargeable battery module, and more particularly, to a rechargeable battery module that connects a sensing portion of a flexible printed circuit (FPC) to a bus bar. Background Art

[0002] Unlike primary batteries, rechargeable batteries are batteries that can be repeatedly charged and discharged. Small-capacity rechargeable batteries are used in small portable electronic devices such as mobile phones, laptop computers, and camcorders.

[0003] High-capacity, high-density secondary batteries are used as power sources for driving motors in hybrid vehicles and electric vehicles or for energy storage. Rechargeable batteries can be used to drive motors of hybrid vehicles that require relatively high energy density, for example, by forming a rechargeable battery module including a plurality of battery cells connected in series and / or in parallel.

[0004] The rechargeable battery module is equipped with a flexible printed circuit (FPC) that detects voltage or current from a bus bar and transmits a detection signal. The FPC sensing structure solders the FPC to a separate nickel tab (Ni-Tab) and welds the tab to an aluminum (Al) bus bar.

[0005] However, nickel tabs (Ni-Tab) are associated with increased costs because they require raw nickel, a soldering process for forming a joint, a coating process for forming an anti-corrosion coating, and a jig for a guide.

[0006] Due to the nickel tab, deformation (eg, S-deformation) of the FPC causes sagging during movement. Such sagging in the FPC may occur during welding of the aluminum busbar and the nickel tab, making it difficult to form an in-position joint of the FPC and the nickel tab for the busbar. Summary of the invention

[0007] The present disclosure provides a rechargeable battery module capable of directly bonding a flexible printed circuit (FPC) to a bus bar. The present disclosure also provides a rechargeable battery module capable of achieving in-situ bonding of a flexible printed circuit (FPC) to a bus bar.

[0008] A rechargeable battery module according to an embodiment of the present disclosure includes: a bus bar bracket covering a plurality of battery cells; a bus bar disposed on the bus bar bracket to electrically connect the battery cells; and a flexible printed circuit (FPC) attached to the bus bar for sending signals and detecting current in the bus bar, wherein the flexible printed circuit includes a thin copper film attached between inner surfaces of a pair of covering layers, wherein the thin copper film is exposed as a unit film portion through a plurality of openings formed in the pair of covering layers, the thin copper film and the pair of covering layers are bent, and the unit film portion is formed into multiple layers and welded to the bus bar.

[0009] The unit film portion has a thickness of 0.035 mm, and the total thickness of the multiple layers is equal to 0.035 mm multiplied by the number of layers.

[0010] The flexible printed circuit includes a main line portion extending in a first direction on the bus bar support and a branch line portion protruding from the main line portion in a second direction crossing the first direction and further extending in the first direction. The unit film portion may be connected to the branch line portion.

[0011] The branch line sections are attached to the bus bars.

[0012] In some embodiments, a rechargeable battery module has two unit film parts arranged in a first direction.

[0013] The unit film portion may include a first unit portion and a second unit portion sequentially arranged in the first direction, and the first unit portion and the second unit portion may be bent about a second-direction bending axis set in the second direction and overlap each other.

[0014] The first unit portion may include a first planar portion connected to a first inclined portion at a first inclination angle θ1, the second unit portion may include a second planar portion connected to a second inclined portion at a second inclination angle θ2 greater than the first inclination angle, the first planar portion and the second planar portion may include a connection area extending in a second direction, are stacked in sequence on the bus bar, and are welded to the bus bar.

[0015] In some embodiments, the rechargeable battery module has two unit film parts arranged in the second direction.

[0016] The unit film portion may include a first unit portion and a second unit portion sequentially arranged in the second direction, and the first unit portion and the second unit portion may be bent about a first-direction bending axis set in the first direction and overlap each other.

[0017] The first unit portion may include a first planar portion connected to a first inclined portion at a first inclination angle θ21, the second unit portion may include a second planar portion connected to a second inclined portion at a second inclination angle θ22 greater than the first inclination angle, the first planar portion and the second planar portion may include a connection area extending in a first direction, stacked in sequence on a bus bar, and welded to the bus bar.

[0018] In some embodiments, the rechargeable battery module has three unit film parts arranged in the second direction.

[0019] The unit film portion may include a first unit portion, a second unit portion and a third unit portion arranged in sequence along the second direction, wherein the first unit portion and the second unit portion can be bent around a first direction bending axis set in the first direction and overlap each other, and the second unit portion and the third unit portion can be bent around another first direction bending axis set in the first direction and overlap each other.

[0020] The first unit portion may include a first planar portion connected to a first inclined portion at a first inclination angle θ31, the second unit portion may include a second planar portion connected to a second inclined portion at a second inclination angle θ32 greater than the first inclination angle, the third unit portion may include a third planar portion connected to a third inclined portion at a third inclination angle θ33 greater than the second inclination angle, the first planar portion, the second planar portion and the third planar portion may include a connection area extending in a first direction, are stacked in sequence on a busbar, and are welded to the busbar.

[0021] In some embodiments, a rechargeable battery module has three unit film parts arranged in a first direction.

[0022] The unit film portion may include a first unit portion, a second unit portion and a third unit portion arranged in sequence along a first direction, wherein the first unit portion and the second unit portion can be bent around a second direction bending axis set in the second direction and overlap each other, and the second unit portion and the third unit portion can be bent around another second direction bending axis set in the second direction and overlap each other.

[0023] The unit film portion may include a first unit portion, a second unit portion, a third unit portion and a fourth unit portion arranged in sequence along a first direction, wherein the first unit portion and the second unit portion can be bent around a second direction bending axis set in the second direction and overlap each other, the second unit portion and the third unit portion can be bent around another second direction bending axis set in the second direction and overlap each other, and the third unit portion and the fourth unit portion can be bent around another second direction bending axis set in the second direction and overlap each other.

[0024] In some embodiments, a rechargeable battery module has four unit film parts arranged in a first direction and a second direction.

[0025] The unit film portion may include a first unit portion and a second unit portion sequentially arranged in the first direction, and a third unit portion and a fourth unit portion respectively arranged from the first unit portion and the second unit portion in the second direction and sequentially arranged in the first direction.

[0026] According to the rechargeable battery module of the embodiment, the thin copper film is exposed as a unit film part through a plurality of openings formed in the cover layer, the thin copper film and the cover layer are bent, and the unit film part is formed into multiple layers and welded to a bus bar made of aluminum.

[0027] Therefore, according to the embodiment, the unit film portion made of copper is formed into multiple layers, thereby directly bonding the flexible printed circuit (FPC) and the bus bar made of aluminum. In addition, according to the embodiment, the flexible printed circuit (FPC) can be bonded to the bus bar at the correct position. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a partial cross-sectional view of a rechargeable battery module according to a first embodiment of the present disclosure.

[0029] Figure 2 yes Figure 1 A perspective view of the flexible printed circuit and cell film portion before bending.

[0030] Figure 3 yes Figure 2 A perspective view of a cell membrane portion during bending.

[0031] Figure 4 yes Figure 2 A top view of the unit film portion in the bending completed state.

[0032] Figure 5 It is arranged on the busbar Figure 4 A cross-sectional view of the curved unit film portion taken along line VV.

[0033] Figure 6 It is welded on the busbar Figure 4 A cross-sectional view of a unit film portion taken along line VV.

[0034] Figure 7 is a top view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a second embodiment of the present disclosure.

[0035] Figure 8 yes Figure 7A top view of the unit film portion in the bending completed state.

[0036] Fig. 9 It is arranged on the busbar Figure 8 A cross-sectional view of the bent unit film portion taken along line IX-IX.

[0037] Fig.10 It is welded on the busbar Figure 8 A cross-sectional view of a unit film portion taken along line IX-IX.

[0038] Fig.11 is a perspective view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a third embodiment of the present disclosure.

[0039] Fig.12 yes Fig.11 A perspective view of the unit film portion in the bending completed state.

[0040] Fig.13 It is arranged on the busbar Fig.12 A cross-sectional view of the bent unit film portion taken along line XIII-XIII.

[0041] Fig.14 It is welded on the busbar Fig.12 A cross-sectional view of a unit film portion taken along line XIII-XIII.

[0042] Fig.15 is a top view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a fourth embodiment of the present disclosure.

[0043] Fig.16 2 is a perspective view of a primary bending state and a secondary bending state of a flexible printed circuit and a unit film portion in a rechargeable battery module according to a fifth embodiment of the present disclosure.

[0044] Fig.17 yes Fig.16 A perspective view of the unit film portion after the triple bending is completed.

[0045] Fig.18 is a top view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a sixth embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] Hereinafter, the present disclosure will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the present invention are shown. Those skilled in the art will recognize that the described embodiments may be modified in various ways without departing from the scope of the present disclosure. The accompanying drawings and descriptions are to be considered illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals represent the same elements.

[0047] Figure 1 is a partial cross-sectional view of a rechargeable battery module according to a first embodiment of the present disclosure. Figure 1 , the rechargeable battery module of the first embodiment includes a plurality of battery cells 10 formed of rechargeable batteries, a bus bar holder 20 , a bus bar 30 , and a flexible printed circuit (FPC) 40 .

[0048] The rechargeable battery module of the first embodiment may have a module frame of various structures, and the following configuration will be described as an example. A plurality of battery cells 10 are formed as a rechargeable battery and are stacked in a first direction (x-axis direction).

[0049] A pair of end plates are provided at both ends of the stacked battery cells 10 in the first direction to constrain the battery cells 10 in the first direction (x-axis direction). A pair of side plates are provided at both sides of the battery cells 10 in a second direction (y-axis direction) intersecting the first direction and connected to the pair of end plates to constrain the battery cells 10 in the second direction.

[0050] The battery cells 10 may be arranged in one row or two rows. When arranged in two rows, an additional center plate may be arranged between a pair of side plates. The center plate extends between the two rows of battery cells 10 in the first direction to constrain the battery cells 10 on both sides in the second direction.

[0051] The bus bar holder 20 may include a bus bar support 25 for connecting and insulating electrode terminals (not shown) of the battery cells 10 , and a vent portion (not shown) for discharging vent gas of the battery cells 10 .

[0052] The busbar support 25 supports the busbars 30 that connect the electrode terminals in series or in parallel, while exposing the electrode terminals in the third direction (the height direction of the electrodes, the z-axis direction) to cover the other parts of the battery cell 10. The third direction (the height direction of the battery cell, the z-axis direction) intersects the first direction (the thickness direction of the battery cell, the x-axis direction) and the second direction (the length direction of the battery cell, the y-axis direction).

[0053] The flexible printed circuit (FPC) 40 is configured to be attached to the bus bar 30 to detect a current flowing in the bus bar 30 electrically connecting the battery cells 10 and transmit a detection signal to a battery management system (BMS).

[0054] The rechargeable battery module of the first embodiment may further include a top cover 70. The top cover 70 is disposed on the bus bar 30 and is externally coupled to the bus bar holder 20 to cover a plurality of bus bars (not shown) and the bus bar holder 20.

[0055] Figure 2 yes Figure 1 A perspective view of the flexible printed circuit and cell film portion before bending. Figure 3 yes Figure 2 Perspective view of the cell membrane portion during bending, Figure 4 yes Figure 2 A top view of the unit film portion in the bending completed state.

[0056] Reference Figures 2 to 4 The flexible printed circuit 40 is formed by providing a thin copper film between inner surfaces of a pair of cover layers 41 and 42 attached to each other. The thin copper film is exposed as a unit film portion 43 through a plurality of openings 411 and 421 formed in the cover layers 41 and 42.

[0057] Figure 5 It is arranged on the busbar Figure 4 A cross-sectional view of the curved unit film portion taken along line VV, Figure 6 It is welded on the busbar Figure 4 A cross-sectional view of a unit film portion taken along line VV.

[0058] Reference Figure 5 and Figure 6 , the thin copper film and the cover layers 41 and 42 are bent, and the unit film portion 43 is formed into multiple layers and welded to the bus bar 30 made of aluminum. In this way, the multi-layer unit film portion 43 enables and strengthens welding between different materials such as copper and aluminum.

[0059] Since the flexible printed circuit 40 does not use a nickel tab, the flexible printed circuit 40 does not significantly deform and sag during movement. Therefore, the multi-layer unit film portion 43 facilitates in-place bonding of the flexible printed circuit 40 and the bus bar 40.

[0060] Since the unit film portion 43 has a thickness of 0.035 mm, the total thickness of the multiple layers is equal to 0.035 mm multiplied by the number of layers.

[0061] In the first embodiment, the two-layer unit film portion 43 has a thickness of 0.07 mm, which is twice the thickness of 0.035 mm.

[0062] Since the two-layer unit film portion 43 formed by bending has improved mechanical strength compared with a one-layer structure, tearing during movement and handling, puncture during welding, and pinhole failure may be effectively prevented for direct bonding to the aluminum bus bar 30 .

[0063] Refer again Figures 2 to 4 , the flexible printed circuit 40 includes a main line portion 44 and a branch line portion 45. The main line portion 44 is provided on the bus bar support 20 and extends in a first direction (x-axis direction). The branch line portion 45 is connected to the main line portion 44 in a second direction (y-axis direction) intersecting the first direction and protrudes from the main line portion 44, and further extends in the first direction.

[0064] The unit film portion 43 is a portion joined to the bus bar 30, and is connected to the branch portion 45. The branch portion 45 is provided corresponding to the bus bar 30. The branch portion 45 is attached to the bus bar 30. In the first embodiment, there are two unit film portions 43 connected in the first direction (x-axis direction).

[0065] The unit film portion 43 includes a first unit portion 431 and a second unit portion 432 sequentially arranged in a first direction (x-axis direction). The first unit portion 431 and the second unit portion 432 are bent about a second direction bending axis BSy set in a second direction (y-axis direction) and overlap each other.

[0066] Refer again Figure 5 and Figure 6 In the welded state, the first unit portion 431 includes a first planar portion F1 connected to a first inclined portion S1 at a first inclined angle θ1, and the second unit portion 432 includes a second planar portion F2 connected to a second inclined portion S2 at a second inclined angle θ2 greater than the first inclined angle θ1.

[0067] The first planar portion F1 and the second planar portion F2 include a connection area extending in the second direction (y-axis direction), are sequentially stacked on the bus bar 30, and are welded to the bus bar 30. Compared with a one-layer structure, the first planar portion F1 and the second planar portion F2 forming a two-layer structure can effectively prevent puncture and pinhole defects during welding. Moreover, the current signal of the bus bar 30 is transmitted to the branch line portion 45 and the main line portion 44 through the welded first planar portion F1 and the second planar portion F2 via the first inclined portion S1 and the second inclined portion S2.

[0068] In the flexible printed circuit 40 of the first embodiment, the branch line portion 45 and the unit film portion 43 generate waste on both sides in the x-axis direction compared with the main line portion 44. The flexible printed circuit 40 of the first embodiment allows the unit film portion 43 to be formed while minimizing the generation of such waste.

[0069] Hereinafter, various embodiments of the present disclosure will be described. Compared with the first embodiment and the previously described embodiments, descriptions of the same parts will be omitted, and descriptions of different parts will be described.

[0070] Figure 7 is a top view of a flexible printed circuit and a unit film portion in a rechargeable battery module according to a second embodiment of the present disclosure before bending, Figure 8 yes Figure 7 A top view of the unit membrane portion of the bending completion state. Figure 7 and Figure 8 In the second embodiment, two unit film portions of the flexible printed circuit 50 are arranged in the second direction (y-axis direction).

[0071] Fig. 9 It is arranged on the busbar Figure 8 A cross-sectional view of the curved unit film portion taken along line IX-IX, Fig.10 It is welded on the busbar Figure 8 A cross-sectional view of a unit film portion taken along line IX-IX.

[0072] Reference Figures 7 to 10 The unit film portion 53 includes a first unit portion 531 and a second unit portion 532 sequentially arranged along the second direction (y-axis direction). The first unit portion 531 and the second unit portion 532 are bent around a first direction bending axis BSx set in the first direction (x-axis direction) and overlap each other.

[0073] In a welded state, the first unit portion 531 includes a first planar portion F21 connected to a first inclined portion S21 at a first inclined angle θ21, and the second unit portion 532 includes a second planar portion F22 connected to a second inclined portion S22 at a second inclined angle θ22 greater than the first inclined angle θ21.

[0074] The first planar portion F21 and the second planar portion F22 include a connection area extending in the first direction (x-axis direction), are sequentially stacked on the bus bar 30, and are welded to the bus bar 30. Compared with a one-layer structure, the first planar portion F21 and the second planar portion F22 forming a two-layer structure can effectively prevent puncture and pinhole defects during welding. Moreover, the current signal of the bus bar 30 is transmitted to the branch line portion 55 and the main line portion 54 through the welded first planar portion F21 and the second planar portion F22 via the first inclined portion S21 and the second inclined portion S22.

[0075] In the flexible printed circuit 50 of the second embodiment, the branch line portion 55 and the unit film portion 53 generate scraps on both sides in the x-axis direction compared to the main line portion 54. When the unit film portion 53 is formed, the flexible printed circuit 50 of the second embodiment generates more scraps on both sides in the x-axis direction of the unit film portion 53 due to the second unit portion 532 compared to the flexible printed circuit 40 of the first embodiment.

[0076] Fig.11 is a perspective view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a third embodiment of the present disclosure, Fig.12 yes Fig.11 A perspective view of the unit membrane section in the completed bending state. Fig.11 and Fig.12 In the third embodiment, the unit film portion of the flexible printed circuit 60 is formed of three and arranged in the second direction (y-axis direction).

[0077] Fig.13 It is arranged on the busbar Fig.12 A cross-sectional view of the curved unit film portion taken along line XIII-XIII, Fig.14 It is welded on the busbar Fig.12 A cross-sectional view of a unit film portion taken along line XIII-XIII.

[0078] Reference Figures 11 to 14 The unit film portion 63 includes a first unit portion 631, a second unit portion 632, and a third unit portion 633. The first unit portion 631 and the second unit portion 632 are bent around a first direction bending axis BSx1 set in the first direction (x-axis direction) and overlap each other. The second unit portion 632 and the third unit portion 633 are bent around another first direction bending axis BSx2 set in the first direction (x-axis direction) and overlap each other.

[0079] In the welded state, the first unit portion 631 includes a first planar portion F31 connected to a first inclined portion S31 at a first inclination angle θ31, the second unit portion 632 includes a second planar portion F32 connected to a second inclined portion S32 at a second inclination angle θ32 greater than the first inclination angle θ31, and the third unit portion 633 includes a third planar portion F33 connected to a third inclined portion S33 at a third inclination angle θ33 greater than the second inclination angle θ32.

[0080] The first plane portion F31, the second plane portion F32, and the third plane portion F33 include a connection area extending in the first direction (x-axis direction), are sequentially stacked on the bus bar 30, and are welded to the bus bar 30. Compared with a one-layer structure or a two-layer structure, the first plane portion F31, the second plane portion F32, and the third plane portion F33 forming a three-layer structure can effectively prevent puncture and pinhole defects during welding. Moreover, the current signal of the bus bar 30 is transmitted to the branch line portion 65 and the main line portion 64 through the welded first plane portion F31, the second plane portion F32, and the third plane portion F33 via the first inclined portion S31, the second inclined portion S32, and the third inclined portion S33.

[0081] In the flexible printed circuit 60 of the third embodiment, wastes are generated on both sides of the unit film portion 63 in the x-axis direction. When forming the unit film portion 63, the flexible printed circuit 60 of the third embodiment generates more wastes on both sides of the unit film portion 63 in the x-axis direction due to the second unit portion 632 and the third unit portion 633 compared to the flexible printed circuit 40 of the first embodiment.

[0082] Fig.15 is a top view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a fourth embodiment of the present disclosure. Fig.15 In the fourth embodiment, the unit film portion of the flexible printed circuit 80 is formed of three and arranged in the first direction (x-axis direction).

[0083] The unit film portion 83 includes a first unit portion 831, a second unit portion 832, and a third unit portion 833 which are sequentially arranged along a first direction (x-axis direction). The first unit portion 831 and the second unit portion 832 are bent around a second-direction bending axis BSy1 set in the second direction (y-axis direction) and overlap each other. The second unit portion 832 and the third unit portion 833 are bent around another second-direction bending axis BSy2 set in the second direction (y-axis direction) and overlap each other.

[0084] The first unit portion 831, the second unit portion 832, and the third unit portion 833 forming a three-layer structure may effectively prevent puncture and pinhole defects during welding, compared to a one-layer structure or a two-layer structure.

[0085] In the flexible printed circuit 80 of the fourth embodiment, the unit film portion 83 generates waste on both sides in the x-axis direction. Since the flexible printed circuit 80 further includes the third unit portion 833, when forming the unit film portion 83, the flexible printed circuit 80 of the fourth embodiment generates less waste on both sides in the x-axis direction than the flexible printed circuit 40 of the first embodiment.

[0086] Fig.16 is a perspective view of a primary bending state and a secondary bending state of a flexible printed circuit and a unit film portion in a rechargeable battery module according to a fifth embodiment of the present disclosure, Fig.17 yes Fig.16 A perspective view of the unit membrane section after the three-fold bending is completed. Fig.16 and Fig.17 In the fifth embodiment, the unit film portions of the flexible printed circuit 90 are formed of four and arranged in the first direction (x-axis direction).

[0087] The unit film portion 93 includes a first unit portion 931, a second unit portion 932, a third unit portion 933, and a fourth unit portion 934 which are sequentially arranged along a first direction (x-axis direction). The first unit portion 931 and the second unit portion 932 are bent around a second direction bending axis BSy1 set in the second direction (y-axis direction) and overlap each other. The second unit portion 932 and the third unit portion 933 are bent around another second direction bending axis BSy2 set in the second direction (y-axis direction) and overlap each other. The third unit portion 933 and the fourth unit portion 934 are bent around another second direction bending axis BSy3 set in the second direction (y-axis direction) and overlap each other.

[0088] The first unit portion 931 , the second unit portion 932 , the third unit portion 933 , and the fourth unit portion 934 forming a four-layer structure may effectively prevent puncture and pinhole defects during welding, compared to a one-layer structure, a two-layer structure, or a three-layer structure.

[0089] In the flexible printed circuit 90 of the fifth embodiment, the unit film portion 93 generates waste on both sides in the x-axis direction. Since the flexible printed circuit 90 further includes the third unit portion 933 and the fourth unit portion 934, the flexible printed circuit 90 of the fifth embodiment generates less waste on both sides in the x-axis direction when the unit film portion 93 is formed, compared with the flexible printed circuit 40 of the first embodiment.

[0090] Fig.18 is a top view of a flexible printed circuit and a unit film portion before bending in a rechargeable battery module according to a sixth embodiment of the present disclosure. Fig.18 In the sixth embodiment, the unit film portions of the flexible printed circuit 98 are formed of four and are arranged in the first direction (x-axis direction) and the second direction (y-axis direction).

[0091] The unit film portion 96 includes a first unit portion 961 and a second unit portion 962 arranged in sequence along a first direction (x-axis direction), and a third unit portion 963 and a fourth unit portion 964 arranged from the first unit portion 961 and the second unit portion 962 respectively along the second direction (y-axis direction) and arranged in sequence along the first direction (x-axis direction).

[0092] The third unit portion 963 and the fourth unit portion 964 are bent about a first-direction bending axis BSx set in the first direction (x-axis direction), and respectively overlap the first unit portion 961 and the second unit portion 962. The fourth unit portion 964 and the second unit portion 962 overlapping each other are bent about a second-direction bending axis BSy set in the second direction (y-axis direction), and overlap the first unit portion 961 and the third unit portion 963 overlapping each other.

[0093] The first unit portion 961, the second unit portion 962, the third unit portion 963, and the fourth unit portion 964 forming a four-layer structure may effectively prevent puncture and pinhole defects during welding, compared to a one-layer structure, a two-layer structure, or a three-layer structure.

[0094] In the flexible printed circuit 98 of the sixth embodiment, the unit film portion 96 generates waste on both sides in the x-axis direction. Since the flexible printed circuit 98 further includes the third unit portion 963 and the fourth unit portion 964, the flexible printed circuit 98 of the sixth embodiment generates more waste on both sides in the x-axis direction when the unit film portion 96 is formed, compared with the flexible printed circuit 40 of the first embodiment.

[0095] While the present disclosure has been described in connection with what are presently considered to be practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the purview of the appended claims.

[0096] <Description of Reference Signs>

[0097] 10: Battery cell 20: Bus bar bracket

[0098] 25: Busbar support 30: Busbar

[0099] 40, 50, 60, 80, 90, 98: Flexible printed circuit (FPC)

[0100] 41, 42: Covering layer

[0101] 43, 53, 63, 83, 93, 96: Unit film part

[0102] 44, 54, 64: Main line 45, 55, 65: Branch line

[0103] 70: Top cover 411, 421: Opening

[0104] 431, 531, 631, 831, 931, 961: Part 1

[0105] 432, 532, 632, 832, 932, 962: Part 2

[0106] 633, 833, 933, 963: Part of Unit 3

[0107] 934, 964: Part 4

[0108] BSx, BSx1, BSx2: bending axis in the first direction

[0109] BSy, BSy1, BSy2, BSy3: Second direction bending axis

[0110] F1, F21, F31: first plane part F2, F22, F32: second plane part

[0111] F33: third plane part S1, S21, S31: first inclined part

[0112] S2, S22 and S32: second inclined portion S33: third inclined portion

[0113] θ1, θ21, θ31: first tilt angle θ2, θ22, θ32: second tilt angle

[0114] θ33: The third tilt angle

Claims

1. A rechargeable battery module comprising: A busbar support covering multiple battery cells; A bus bar, disposed on the bus bar bracket to electrically connect the battery cells; as well as a flexible printed circuit attached to the bus bar, the flexible printed circuit configured to send signals and detect current in the bus bar, the flexible printed circuit comprising a thin copper film attached between inner surfaces of a pair of cover layers, wherein the thin copper film is exposed as a unit film portion through a plurality of openings formed in the pair of cover layers, wherein the thin copper film and the pair of cover layers are bent, and The unit film portion is formed into multiple layers and welded to the bus bar.

2. The rechargeable battery module according to claim 1, wherein: The unit film portion has a thickness of 0.035 mm, and The thickness of the multiple layers is equal to 0.035 mm multiplied by the number of layers.

3. The rechargeable battery module according to claim 1, wherein: The flexible printed circuit comprises: a main line portion extending along a first direction on the busbar support; and a branch line portion that projects from the main line portion in a second direction intersecting the first direction and further extends in the first direction, and Wherein, the unit film portion is connected to the branch line portion.

4. The rechargeable battery module according to claim 3, wherein: The branch line portion is attached to the bus bar.

5. The rechargeable battery module according to claim 3, wherein: The rechargeable battery module has two of the unit film portions arranged in the first direction.

6. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion and a second unit portion sequentially arranged along the first direction, and The first unit portion and the second unit portion are bent around a second direction bending axis set in the second direction so that the first unit portion and the second unit portion overlap each other.

7. The rechargeable battery module according to claim 6, wherein: The first unit portion includes a first planar portion connected to a first inclined portion at a first inclined angle, wherein the second unit portion includes a second planar portion connected to a second inclined portion at a second inclined angle greater than the first inclined angle, and The first planar portion and the second planar portion include a connection region extending in the second direction, are sequentially stacked on the bus bar, and are welded to the bus bar.

8. The rechargeable battery module according to claim 3, wherein: The rechargeable battery module has two of the unit film portions arranged in the second direction.

9. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion and a second unit portion sequentially arranged along the second direction, and The first unit portion and the second unit portion are bent around a first-direction bending axis set in the first direction so that the first unit portion and the second unit portion overlap each other.

10. The rechargeable battery module according to claim 9, wherein: The first unit portion includes a first planar portion connected to a first inclined portion at a first inclined angle, wherein the second unit portion includes a second planar portion connected to a second inclined portion at a second inclined angle greater than the first inclined angle, and The first planar portion and the second planar portion include connection areas extending in the first direction, are sequentially stacked on the bus bar, and are welded to the bus bar.

11. The rechargeable battery module according to claim 3, wherein: The rechargeable battery module has three of the unit film portions arranged in the second direction.

12. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion, a second unit portion and a third unit portion arranged in sequence along the second direction, wherein the first unit portion and the second unit portion are bent about a first-direction bending axis set in the first direction so that the first unit portion and the second unit portion overlap each other, and The second unit portion and the third unit portion are bent around another first-direction bending axis set in the first direction, so that the second unit portion and the third unit portion overlap each other.

13. The rechargeable battery module according to claim 12, wherein: The first unit portion includes a first planar portion connected to a first inclined portion at a first inclined angle, wherein the second unit portion includes a second planar portion connected to a second inclined portion at a second inclined angle greater than the first inclined angle, wherein the third unit portion includes a third planar portion connected to a third inclined portion at a third inclined angle greater than the second inclined angle, and The first planar portion, the second planar portion, and the third planar portion include connection areas extending in the first direction, are sequentially stacked on the bus bar, and are welded to the bus bar.

14. The rechargeable battery module according to claim 3, wherein: The rechargeable battery module has three of the unit film portions arranged in the first direction.

15. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion, a second unit portion and a third unit portion arranged in sequence along the first direction, wherein the first unit portion and the second unit portion are bent about a second direction bending axis set in the second direction so that the first unit portion and the second unit portion overlap each other, and The second unit portion and the third unit portion are bent around another second-direction bending axis set in the second direction, so that the second unit portion and the third unit portion overlap each other.

16. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion, a second unit portion, a third unit portion and a fourth unit portion arranged in sequence along the first direction, wherein the first unit portion and the second unit portion are bent around a second direction bending axis set in the second direction so that the first unit portion and the second unit portion overlap each other, wherein the second unit portion and the third unit portion are bent about another second-direction bending axis set in the second direction so that the second unit portion and the third unit portion overlap each other, and The third unit portion and the fourth unit portion are bent around another second-direction bending axis set in the second direction, so that the third unit portion and the fourth unit portion overlap each other.

17. The rechargeable battery module according to claim 3, wherein: The rechargeable battery module has four of the unit film portions arranged in the first direction and the second direction.

18. The rechargeable battery module according to claim 3, wherein: The unit film portion includes a first unit portion and a second unit portion sequentially arranged along the first direction, and The unit film portion includes a third unit portion and a fourth unit portion, and the third unit portion and the fourth unit portion are arranged from the first unit portion and the second unit portion respectively along the second direction, and are arranged in sequence along the first direction.

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