Secondary Battery Module

Abstract

To provide a secondary battery module capable of protecting a connection part of a sensing part on a flexible printed circuit (FPC) and a bus bar from a flow transmitted from the bus bar.SOLUTION: A secondary battery module including a plurality of battery cells stacked on one another in a first direction, comprises: a bus bar holder that stores a bus bar 40 connecting an electrode terminal and covers battery cells; and a flexible printed circuit 50 that is connected to the bus bar and is coated with a film. The flexible printed circuit comprises: a body 51 that forms a plurality of signal lines 511 inside of the film; a sensing part that is connected to the bus bar side; a connection part 53 that forms a connection line 531 connecting the signal lines and the sensing part inside of the film, and has a prescribed connection width; and a slot hole that penetrates the film along the periphery of the sensing part so as to form the connection part, and has a prescribed penetration width.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a secondary battery module, and more particularly to a secondary battery module in which a sensing portion of a flexible printed circuit (FPC) is connected to a bus bar. [Background technology]

[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, laptops, and camcorders.

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

[0004] For example, a secondary battery module uses a sensing tab to connect a flexible printed circuit (FPC) for measuring cell voltage to a bus bar made of aluminum or copper.

[0005] Swelling that occurs in the battery cell causes the busbar connected to the electrode terminal of the battery cell to move, which affects the sensing part of the flexible printed circuit and the welding part of the sensing tab. Therefore, the flexible printed circuit has a structure that can absorb the movement in the sensing part.

[0006] However, the total elongation of the secondary battery module is within 3 mm, and the sensing unit provided to accommodate this may be formed in an excessively large or small shape.

[0007] If the sensing part is formed in an excessively large shape, it will require an excessively large area for flow absorption, and the long length and flexible material of the sensing part will make it difficult to handle during processing, which may result in poor fixation and welding.

[0008] In addition, if the sensing part is formed in an excessively small shape, the length of the sensing part for flow absorption is short, but the flow absorption structure is open to the outside, which causes a curling phenomenon during the FPC manufacturing process, which can lead to poor fixing and welding. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of one embodiment of the present invention is to provide a secondary battery module in which a connection between a sensing part of a flexible printed circuit (FPC) and a bus bar can be protected from a flow transmitted from the bus bar.

[0010] An object of one embodiment of the present invention is to provide a secondary battery module in which a sensing portion of a flexible printed circuit (FPC) and a connection portion of a sensing tab connected to a bus bar can be protected from flow transmitted from the bus bar. [Means for solving the problem]

[0011] A secondary battery module according to one embodiment of the present invention includes a plurality of battery cells stacked in a first direction, a bus bar holder covering the battery cells while exposing electrode terminals of the battery cells on both sides in a second direction (y-axis direction) intersecting the first direction (x-axis direction) in a third direction (z-axis direction) intersecting the second direction, a bus bar connecting the electrode terminals exposed to the bus bar holder, and a flexible printed circuit (FPC) connected to the bus bar and covered with a film, wherein the flexible printed circuit includes a body portion forming a plurality of signal lines within the film, a sensing portion connected to the bus bar side, a connecting portion forming connecting lines within the film connecting the signal lines and the sensing portion and having a predetermined connecting width, and a slot hole having a predetermined through width penetrating the film around the sensing portion to form the connecting portion.

[0012] The main body portion has a planar area having a length in the first direction and a width in the second direction, and the sensing portion may be formed within the planar area while enclosing the planar area of the main body portion and connected to the main body portion by the connecting portion.

[0013] The connecting line may have a line width (W3) set in the first direction, and the connecting portion may have a first connecting width (W1) and a second connecting width (W2) set between both sides of the connecting line and both ends of the slot hole in the first direction, respectively.

[0014] Both ends of the slot hole may be formed toward the connecting line with a round shape having a diameter (D1) equal to the through width.

[0015] The slot hole has a distance (L2) set from the first direction end of the sensing unit toward the connecting line, and the distance may be set to be equal to or greater than the flow rate of the entire module.

[0016] The distance between the slot holes may be set to be greater than the sum of the swelling amounts of the individual battery cells.

[0017] The first connection width and the second connection width may be set to be larger than the line width.

[0018] The bus bar may be made of aluminum, the sensing portion may be made of copper, and the welded portion between the bus bar and the sensing portion may form a mixed structure of aluminum and copper.

[0019] The welded portion between the bus bar and the sensing portion may be formed by one of ultrasonic welding, laser welding, and spot welding.

[0020] The bus bar and the sensing part may be formed by one of bonding, anisotropic conductive film (ACF) bonding, soldering, and mechanical bonding.

[0021] Both ends of the slot hole may be rounded toward the connecting line with a diameter (D2) greater than the through width.

[0022] The insides of the rounds at both ends of the slot hole may be connected to the slot hole in the first direction, and the outsides of the rounds may be connected to the slot hole inclined at an angle (θ) with respect to the first direction.

[0023] The diameter (D2) formed at both ends of the slot hole may be set to be equal to or larger than the flow rate of the entire module.

[0024] The sensing unit may include a welded portion welded to the bus bar, a notch portion formed on at least one side of the welded portion, and an adhesive portion for strengthening adhesive strength provided to the notch portion.

[0025] The bus bars may be attached to the flexible printed circuit with adhesive or tape.

[0026] The adhesive or tape may attach the film covering the sensing portion and the bus bar to the inside of the slot hole in the first direction.

[0027] The sensing portion of the flexible printed circuit may be connected to the bus bar via a sensing tab.

[0028] The sensing tab may include a first connection portion disposed above the slot hole and connected to the sensing portion, and a second connection portion connected to the bus bar. [Effects of the Invention]

[0029] In one embodiment, a secondary battery module includes a flexible printed circuit having a main body, a sensing unit, a slot hole, and a connecting unit. The sensing unit is connected to the bus bar, and the slot hole absorbs flow transmitted from the bus bar, thereby protecting the connecting unit between the sensing unit and the bus bar from flow. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is an exploded perspective view of a secondary battery module according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a partial perspective view of FIG. [Figure 3] 3 is a plan view of a flexible printed circuit and a sensing unit applied to FIG. 2. FIG. [Figure 4] FIG. 10 is a plan view showing a state in which a flexible printed circuit and a sensing unit are arranged on a bus bar. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] 10 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a second embodiment of the present invention. FIG. [Figure 7] 10 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a third embodiment of the present invention. FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. [Figure 9] 10 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a fourth embodiment of the present invention. FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] 13 is a plan view of a flexible printed circuit applied to a secondary battery module and a sensing unit according to a fifth embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts unnecessary for the explanation are omitted in order to clearly explain the present invention, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0032] Fig. 1 is an exploded perspective view of a secondary battery module according to a first embodiment of the present invention, and Fig. 2 is a partial perspective view of Fig. 1. Referring to Fig. 1 and Fig. 2, the secondary battery module of the embodiment includes a plurality of battery cells 10, a bus bar holder 20, a bus bar 40, and a flexible printed circuit (FPC) 50.

[0033] The secondary battery module according to an embodiment may have a module frame with various structures, but a detailed description of the structure will be omitted and only the structure including the main part of the present invention will be described.

[0034] The plurality of battery cells 10 are formed of secondary batteries and are stacked in a first direction (x-axis direction). A pair of end plates are disposed on 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).

[0035] The pair of side plates are arranged on both sides of the battery cell 10 in a second direction (y-axis direction) that intersects with the first direction, and are connected to the pair of end plates to restrict the battery cell 10 in the second direction.

[0036] When the battery cells 10 are arranged in two rows as in the first embodiment, a center plate may be further disposed between the pair of side plates. The center plate is disposed between the two rows of battery cells 10 in the first direction to restrict the battery cells 10 on both sides in the second direction.

[0037] The bus bar holder 20 includes a bus bar support portion 21 for connecting and insulating the electrode terminals 11 and 12 of the battery cells 10 , and a vent portion 22 for discharging vent gas from the battery cells 10 .

[0038] The busbar support portion 21 covers other portions of the battery cell 10 while exposing the electrode terminals 11, 12 in a third direction (cell height, z-axis direction). The third direction (cell height, z-axis direction) intersects with the first direction (cell thickness, x-axis direction) and the second direction (cell length, y-axis direction).

[0039] The busbar 40 is welded to the electrode terminals 11, 12 exposed in the third direction through the busbar support portion 21 to electrically and mechanically connect the electrode terminals 11, 12. In other words, the busbar 40 connects the electrode terminals 11, 12 of the battery cells 10 adjacent in the first direction in parallel or in series.

[0040] The vent portion 22 corresponds to the vent 13 of the battery cell 10 and is configured to discharge the opening pressure and ejected material of the battery cell 10 to the outside of the bus bar holder 20 when the vent 13 is opened during a cell event.

[0041] Busbar support portions 21 corresponding to electrode terminals 11 and 12 in the second direction (cell length, y-axis direction) are arranged on both sides. In this way, vent portions 22 corresponding to vent 13 provided between electrode terminals 11 and 12 are arranged between busbar support portions 21.

[0042] 3 is a plan view of the flexible printed circuit and the sensing unit applied to FIG. 2, and FIG. 4 is a plan view of the flexible printed circuit and the sensing unit arranged on the bus bar. Referring to FIGS. 1 to 4, the bus bar 40 includes a first corresponding portion 41 connected to correspond to the electrode terminals 11 and 12, and a second corresponding portion 42 connected to correspond to the flexible printed circuit 50.

[0043] The flexible printed circuit 50 is connected to the bus bar 40 and is covered with two films 501 and 502. For example, the flexible printed circuit 50 has two films 501 and 502 in the thickness direction, and a printed circuit formed inside the films 501 and 502. When viewed from above, the flexible printed circuit 50 includes a main body 51, a sensing part 52, a connecting part 53, and a slot hole 54.

[0044] The main body 51 includes a plurality of signal lines 511 formed by a printed circuit in two films 501 and 502. For example, the films 501 and 502 in the flexible printed circuit 50 may be formed of a polyimide film or a polyester film.

[0045] Figure 5 is a cross-sectional view taken along line VV in Figure 4. Referring to Figures 2 to 5, the sensing unit 52 is connected to the bus bar 40, is formed of a copper thin film, and is open on one or both sides (not shown). Therefore, the sensing unit 52 can be directly connected to the bus bar 40. Alternatively, the sensing unit 52 can be indirectly connected to the bus bar 40 (see Figure 11).

[0046] The connecting portion 53 forms a connecting line 531 that connects the signal line 511 and the sensing portion 52 within the films 501 and 502, and has an overall connecting width (W1+W2+W3) set by the films 501 and 502.

[0047] The slot hole 54 has a predetermined penetration width and penetrates the films 501 and 502 along the periphery of the sensing unit 52 to form the connecting portion 53. That is, the slot hole 54 is formed by penetrating the films 501 and 502, and the connecting portion 53 is formed without penetrating the films 501 and 502.

[0048] Again, in the flexible printed circuit 50, the main body 51 has a planar area (L*W) that is set by a length (L) in a first direction (x-axis direction) and a width (W) in a second direction (y-axis direction). A plurality of sensing units 52 are formed along the first direction within the planar area (L*W) while enclosing the planar area (L*W) of the main body 51, and are connected to the main body 51 through respective connecting units 53.

[0049] The connecting line 531 has a line width (W3) set in a first direction (x-axis direction). The connecting portion 53 has a first connecting width (W1) and a second connecting width (W2) set in the first direction between both sides of the connecting line 531 and both ends of the slot hole 54. The first connecting width (W1) and the second connecting width (W2) of the connecting portion 53 protect the connecting line 531 and maintain the connection between the sensing unit 52 and the signal line 511.

[0050] Both ends of the slot hole 54 are rounded toward the connecting line 531 with a diameter (D1) equal to the through width. The rounded ends prevent damage due to stress concentration at the ends of the slot hole 54. The slot hole 54 also has a distance (L2) set from the end of the sensing unit 52 in the first direction toward the connecting line 531.

[0051] This distance (L2) is set to be equal to or greater than the flow rate of the entire module. That is, the distance (L2) of the slot holes 54 is set to be greater than the sum of the swelling rates of the individual battery cells 10. This distance (L2) is set to the overall connection width (W1 + W2 + W3) to effectively accommodate the flow rate of the entire module in the first direction while stably maintaining the connection structure or welding structure between the sensing unit 52 and the bus bar 40.

[0052] In addition, since the first connecting width (W1) and the second connecting width (W2) are set larger than the line width (W3), the disconnection of the connecting line 531 can be prevented with respect to the flow amount of the entire module along the first direction.

[0053] Although the slot hole 54 weakens the integration of the sensing part 52 and the signal line 511, the distance (L2) of the connecting part 53 maintains the strength of the connecting line 531 and also allows the slot hole 54 to sufficiently absorb the flow transmitted to the battery cell 10 and the bus bar 40.

[0054] 1, 2, 4, and 5, the bus bar 40 is made of aluminum, and the sensing portion 52 is made of copper. The bus bar 40 and the sensing portion 52 may be connected by ultrasonic welding, laser welding (LW), or spot welding.

[0055] The first corresponding portion 41 of the bus bar 40 may be connected to the electrode terminals 11 and 12 by welding, and the second corresponding portion 42 may be connected to the flexible printed circuit 50 by welding. The second corresponding portion 42 protrudes in the second direction (y-axis direction) from one side of the first corresponding portion 41 and is connected to the sensing portion 52 of the flexible printed circuit 50 by welding. A weld 45 connecting the second corresponding portion 42 and the sensing portion 52 is formed by welding.

[0056] The second corresponding portion 42 has a first length (L21) in the first direction (x-axis direction) and a second length (L22) in the second direction (y-axis direction), with an area (L21*L22). The second corresponding portion 42 supports the sensing portion 52, the connecting portion 53, the slot hole 54, the connecting line 531, and the signal line 511 of the flexible printed circuit 50. The connecting line 531 may be entirely supported, and the signal line 511 may be partially supported.

[0057] As described above, the secondary battery module of the first embodiment stabilizes the connection structure between the bus bar 40 and the sensing unit 52 against the flow amount of the entire module, and can prevent the connection line 531 from being cut.

[0058] In addition, in the secondary battery module of the first embodiment, a wide area of the flexible printed circuit 50 is supported by the second corresponding portion 42 of the bus bar 40, so that the flexible printed circuit 50 can be protected by the flow transmitted from the bus bar 40 while preventing sagging of the flexible printed circuit 50.

[0059] Meanwhile, in the secondary battery module of the first embodiment, the connection line 531 connects the sensing unit 52 to the signal line 511. The sensing unit 52 is connected to the second corresponding portion 42 of the bus bar 40 to sense the battery cell 10 connected to the bus bar 40 and transmits the sensing signal via the connection line 531 and the signal line 511.

[0060] In addition, the connecting portion 53 and the slot holes 54 prevent the flexible printed circuit 50 from opening outward and from being rolled up during the manufacturing process of the flexible printed circuit 50, thereby enabling the sensing unit 52 to be stably fixed to the bus bar 40. Therefore, welding defects due to improper fixing of the sensing unit 52 can be improved.

[0061] Various embodiments of the present invention will be described below. Descriptions of the same configurations as those of the first embodiment and the previously described embodiments will be omitted, and only the different configurations will be described.

[0062] 6 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a second embodiment of the present invention. Referring to FIG. 6, in the flexible printed circuit 250 applied to the secondary battery module of the second embodiment, both ends of the slot hole 254 are formed as rounds with a diameter D2 greater than the through width toward the connection line 531. Therefore, the slot hole 254 has a distance L5 set from the first end of the sensing unit 52 toward the connection line 531.

[0063] This distance (L5) is set to be equal to or greater than the flow rate of the entire module. That is, the distance (L5) of the slot holes 254 is set to be greater than the sum of the swelling rates of the individual battery cells 10. This distance (L5) is set to the overall connection width of the connection portion 253, and can effectively accommodate the flow rate of the entire module along the first direction.

[0064] Meanwhile, the inside of the rounds at both ends of the slot hole 254, i.e., the side adjacent to the sensing unit 52, is connected to the slot hole 254 in the first direction (x-axis direction), and the outside of the rounds, i.e., the side farther from the sensing unit 52, is connected to the slot hole 254 at an angle (θ) relative to the first direction (x-axis direction).

[0065] The outer side of the rounds that are connected at an angle (θ) by the slot holes 254 can more effectively accommodate the flow rate of the entire module in the first direction compared to the slot holes 54 of the first embodiment, and can also partially accommodate the flow rate of the entire module in the second direction.

[0066] When the distance (L5) in the second embodiment is the same as the distance (L2) in the first embodiment, a round with a diameter (D2) larger than the penetration width in the second embodiment can further disperse stress caused by flow compared to a round with a diameter (D1) of the same size as the penetration width in the first embodiment, thereby enabling the module to more effectively respond to the flow volume of the entire module.

[0067] In other words, the connecting portion 253 of the second embodiment stably maintains the connecting structure or welded structure between the sensing portion 52 and the bus bar 40, which can more effectively prevent damage than the connecting portion 53 of the first embodiment stably maintains the connecting structure or welded structure between the sensing portion 52 and the bus bar 40.

[0068] Fig. 7 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a third embodiment of the present invention, and Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 7. Referring to Figs. 7 and 8, in a flexible printed circuit 350 applied to the secondary battery module of the third embodiment, a sensing unit 352 includes a welding portion 45, a notch portion 356, and an adhesive portion 357.

[0069] The notch 356 is formed on at least one side of the welding portion 45. That is, the notch 356 is formed by penetrating the sensing portion 352 and the two films 501 and 502 provided on both sides of the sensing portion 352. The adhesive portion 357 is formed by injecting an adhesive into the notch 356 to further strengthen the adhesive strength between the sensing portion 352 and the films 501 and 502.

[0070] Fig. 9 is a plan view of a flexible printed circuit and a sensing unit applied to a secondary battery module according to a fourth embodiment of the present invention, and Fig. 10 is a cross-sectional view taken along line XX in Fig. 9. Referring to Fig. 9 and Fig. 10, the bus bar 40 and the flexible printed circuit 250 applied to the secondary battery module of the fourth embodiment may be joined to each other.

[0071] For example, the second corresponding portion 42 of the bus bar 40 and the sensing portion 452 may be formed by one of bonding, anisotropic conductive film (ACF) bonding, soldering, and mechanical bonding 453. FIG. 10 shows an anisotropic conductive film (ACF) as an example of the bonding 453.

[0072] In addition, the second corresponding portion 42 of the bus bar 40 and the sensing portion 452 of the flexible printed circuit 250 may be attached with an adhesive or tape T. That is, the tape T is attached to the one-side film 501 covering the sensing portion 452 inside the slot hole 254 and the second corresponding portion 42. The attachment of the tape T makes the bond 453 between the sensing portion 452 and the second corresponding portion 42 stronger.

[0073] 11 is a plan view of a secondary battery module and a flexible printed circuit applied to a sensing unit according to a fifth embodiment of the present invention. Referring to FIG. 11, in the secondary battery module of the fifth embodiment, the sensing unit 52 of the flexible printed circuit 250 is connected to the bus bar 44 via a sensing tab 60. The sensing tab 60 includes a first connecting portion 61 and a second connecting portion 62.

[0074] The first connecting portion 61 is disposed above the slot hole 254 and connected to the sensing portion 52. The connection between the first connecting portion 61 and the sensing portion 52 may be formed by applying the welded portion 45 of the first embodiment and the joint 453 structure of the fourth embodiment. The second connecting portion 62 is connected to the bus bar 44 by welding 441. The sensing tab 60 can prevent the flexible printed circuit 250 from sagging.

[0075] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, and it is natural that these also fall within the scope of the present invention. [Explanation of symbols]

[0076] 10: Battery cell 11, 12: Electrode terminal 13: Vent 20: Busbar holder 21: Busbar support 22: Vent section 40, 44: Busbar 41: First Response Department 42: Second Response Department 44: Busbar 45: Welded section 50: Flexible Printed Circuit (FPC) 51: Main body 52: Sensing unit 53:Connection part 54: Slot Hole 60: Sensing tab 61: 1st connection part 62:Second connection part 254: Slot Hole 350: Flexible printed circuits 352: Sensing unit 356: Notch 357: Adhesive part 452: Sensing unit 453: Joint 501, 502: Film 511: Signal line 531: Connecting line D1: Diameter D2: Diameter L: Length L2: distance L5: distance LW: Laser welding L*W: Plane area L21: First length L22: Second length L21*L22: Area T: Tape W: Width W1: 1st connection width W2: Second connecting width W1+W2+W3: Overall connection width W3: Line width θ: Angle

Claims

1. a plurality of battery cells stacked in a first direction; a bus bar holder covering the battery cell while exposing electrode terminals of the battery cell on both sides in a second direction intersecting the first direction in a third direction intersecting the second direction; a bus bar connecting the electrode terminals exposed to the bus bar holder; and A flexible printed circuit connected to the bus bar and covered with a film Including, The flexible printed circuit a body portion forming a plurality of signal lines within the film; a sensing unit connected to the bus bar side; a connecting portion that forms a connecting line connecting the signal line and the sensing portion within the film and has a connecting width set in the film; and A slot hole having a predetermined penetration width penetrates the film along the periphery of the sensing portion to form the connecting portion. Including, The connecting line has a line width (W3) set in the first direction, The connecting portion has a first connecting width (W1) and a second connecting width (W2) set between both sides of the connecting line and both ends of the slot hole in the first direction, respectively, The slot hole is a distance (L2) between the ends in the first direction; The distance (L2) is A secondary battery module in which the flow rate is set to be equal to or greater than the flow rate of the entire module.

2. The main body portion is a planar area having a length in the first direction and a width in the second direction; The sensing unit The secondary battery module according to claim 1 , wherein the connecting portion is formed within the planar region of the body portion while enclosing the planar region of the body portion and is connected to the body portion by the connecting portion.

3. The secondary battery module of claim 1 , wherein both ends of the slot hole are rounded toward the connection line and have a diameter D1 equal to the through width.

4. The secondary battery module of claim 1 , wherein the distance L2 of the slotted holes is set to be greater than a sum of swelling amounts of the battery cells.

5. The secondary battery module of claim 1 , wherein the first connecting width and the second connecting width are set larger than the line width.

6. the bus bar is made of aluminum; The sensing portion is made of copper, The secondary battery module of claim 1 , wherein the bus bar and the sensing portion are welded together to form a mixed aluminum and copper structure.

7. The secondary battery module of claim 1 , wherein the welded portion between the bus bar and the sensing portion is formed by one of ultrasonic welding, laser welding, and spot welding.

8. The bus bar and the sensing unit are The secondary battery module according to claim 1 , which is formed by one of bonding, anisotropic conductive film bonding, soldering, and mechanical bonding.

9. The secondary battery module of claim 1 , wherein both ends of the slot hole are rounded toward the connection line with a diameter D2 greater than the through width.

10. 10. The secondary battery module of claim 9, wherein inner sides of rounds at both ends of the slot hole are connected to the slot hole in the first direction, and outer sides of the rounds are connected to the slot hole at an angle (θ) with respect to the first direction.

11. The diameter (D2) formed at both ends of the slot hole is The secondary battery module according to claim 9 , wherein the flow rate is set to be equal to or greater than the flow rate of the entire module.

12. The sensing unit a welded portion welded to the bus bar; a notch formed on at least one side of the weld; and The secondary battery module of claim 9 , further comprising an adhesive portion that strengthens adhesive strength provided to the notch portion.

13. The secondary battery module of claim 9 , wherein the bus bar is attached to the flexible printed circuit with an adhesive or tape.

14. The secondary battery module of claim 13 , wherein the adhesive or the tape attaches the film covering the sensing portion and the bus bar on the inner side of the slot hole in the first direction.

15. The secondary battery module of claim 1 , wherein the sensing portion of the flexible printed circuit is connected to the bus bar via a sensing tab.

16. The sensing tab a first connecting portion disposed above the slot hole and connected to the sensing portion; and The secondary battery module of claim 15 , further comprising a second connecting portion connected to the bus bar.

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