Rechargeable battery module
By laser welding of flexible printed circuits and bus bars, the problem of high connection cost of flexible printed circuits is solved, low-cost connection of battery modules is realized, and the competitiveness of battery modules is enhanced.
Patent Information
- Application Number
- CN202411889396.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-05
- Filing Date
- 2024-12-20
- Publication Date
- 2025-07-08
AI Technical Summary
Among the existing rechargeable battery modules, the connection cost between flexible printed circuits (FPCs) and bus bars is high, and the use of nickel wiring increases material and process costs, affecting the price competitiveness of the module.
The extension of the flexible printed circuit is directly connected to the bus bar by laser welding, omitting the nickel patch, and using copper or aluminum foil materials to achieve the desired resistance value and peel strength.
It reduces material costs, improves connection quality, ensures resistance value and peel strength, and enhances the competitiveness of the module.
Smart Images
Figure CN120280662A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a rechargeable battery module. Background Art
[0002] Unlike primary batteries, rechargeable batteries are batteries that are repeatedly charged and discharged. Small-capacity rechargeable batteries are used in portable small electronic devices such as mobile phones, laptop computers, and portable video cameras.
[0003] High-capacity and high-density rechargeable batteries are used as power sources for driving motors in hybrid vehicles and electric vehicles or as energy storage devices. Rechargeable batteries can be used by forming a rechargeable battery module including a plurality of battery cells connected in series and / or in parallel, thereby driving, for example, a motor of a hybrid vehicle that requires a relatively high energy density.
[0004] A rechargeable battery module detects the voltage of a cell by a bus bar connected to the cell and transmits the detected signal through a flexible printed circuit (FPC). A nickel tab is used to connect the FPC to the bus bar. The nickel tab increases the process cost and the material cost.
[0005] The above information disclosed in the technology used as the background of the present disclosure is only for enhancing the understanding of the background of the present disclosure, and thus may include information that does not constitute related art. Summary of the Invention
[0006] One embodiment of the present disclosure includes a rechargeable battery module that improves connection quality by directly connecting a flexible printed circuit (FPC) and a bus bar. One embodiment of the present disclosure includes a rechargeable battery module that can achieve a desired resistance value and peel strength by laser-bonding a welding pattern of a flexible printed circuit (FPC) to a bus bar.
[0007] In one embodiment, a rechargeable battery module includes: a bus bar holder covering a plurality of battery cells; a bus bar on the bus bar holder and electrically connecting the plurality of battery cells; and a flexible printed circuit on the bus bar holder. The flexible printed circuit includes a film coating circuit patterns on two surfaces. The flexible printed circuit is configured to transmit a signal for detecting the voltage of a battery cell among the plurality of battery cells connected to the bus bar. The bus bar includes an extension portion protruding in one direction, and the flexible printed circuit includes a main body portion, a branch portion extending from the main body portion, and an extended portion welded to the extension portion. The extended portion has an area larger than that of the branch portion.
[0008] The extension part may include at least one through-hole penetrating through a foil connected to a circuit pattern, at least one solder pattern exposed by an opening in a film around the at least one through-hole, and a soldering part that joins an extension part exposed through the at least one through-hole to the at least one solder pattern.
[0009] The foil may include copper or aluminum.
[0010] The extension part may have an area defined by a first length in the longitudinal direction of the branch part and a first width in the width direction intersecting the longitudinal direction.
[0011] The branch part may be at the outermost side of the extension part in the width direction. The branch part may have a width smaller than the first width of the extension part and may extend in the longitudinal direction.
[0012] The flexible printed circuit may further include a rounded corner where the branch part and the extension part are connected.
[0013] The at least one through-hole may include two or more through-holes arranged in the width direction and the longitudinal direction of the branch part.
[0014] The at least one through-hole may include a plurality of through-holes. Two of the plurality of through-holes may be arranged in the width direction, and another two of the plurality of through-holes may be arranged in the longitudinal direction.
[0015] Each through-hole may have a slot hole structure having a hole width in the width direction and a hole length in the longitudinal direction.
[0016] The at least one solder pattern may include a plurality of solder patterns. Each of the plurality of solder patterns may include a pattern width part on both sides of each through-hole in the width direction and having a size substantially the same as the hole width, and a pattern length part connected to both sides of the pattern width part in the longitudinal direction and having a radius of curvature larger than that of the slot hole structure of each through-hole.
[0017] The extension part may include an 11th inner coating part between two of the plurality of solder patterns in the width direction and a 12th outer coating part outside the two solder patterns in the width direction. The 11th inner coating part includes a part of the foil coated with the film, and the 12th outer coating part includes another part of the foil coated with the film. The 11th inner coating part may have a size approximately twice that of the 12th outer coating part.
[0018] The extension part may include a first recessed part in the 12th outer coating part.
[0019] The extension part may include a 21st inner coating part between two welding patterns among the multiple welding patterns in the length direction and a 22nd outer coating part outside the two welding patterns in the length direction. The 21st inner coating part includes a part of the foil coated with the film, and the 22nd outer coating part includes another part of the foil coated with the film. The 21st inner coating part may have a size smaller than or equal to that of the 22nd outer coating part.
[0020] The extension part may include a second recessed part in the 22nd outer coating part.
[0021] The welding part may electrically connect the at least one welding pattern and the extension part exposed through the at least one through hole.
[0022] According to one or more embodiments of the present disclosure, by welding and joining the extension part in the branch part of the flexible printed circuit to the extension part of the bus bar, improved connection quality can be achieved while directly connecting the flexible printed circuit (FPC) and the bus bar.
[0023] Furthermore, according to one or more embodiments of the present disclosure, by irradiating a laser on the through holes of the extension part of the flexible printed circuit (FPC), melting the solder, and welding and joining the welding pattern and the extension part exposed by the through holes, a desired resistance value and peel strength at the connection between the bus bar and the flexible printed circuit can be ensured. Description of the Drawings
[0024] Figure 1 A partial top plan view showing a rechargeable battery module according to an embodiment of the present disclosure.
[0025] Figure 2 Showing where the connection part of the flexible printed circuit is connected to the bus bar applied to Figure 1 The top plan view.
[0026] Figure 3 Showing for Figure 2 The enlarged top plan view of the connection part of the flexible printed circuit for the bus bar in.
[0027] Figure 4 Showing the flexible printed circuit applied to Figures 1 to 3 The planar image of the connection part.
[0028] Figure 5 Showing where the connection part of the flexible printed circuit is joined to the bus bar applied to Figure 1 The image.
[0029] Figure 6Images showing a first experimental example and a second experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure.
[0030] Figure 7 Images showing a third experimental example and a fourth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure.
[0031] Figure 8 Images showing a fifth experimental example and a sixth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure.
[0032] Figure 9 Images showing a seventh experimental example and an eighth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure.
[0033] Figure 10 Images showing a ninth experimental example and a tenth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure. Detailed Description
[0034] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in various different ways without departing from the scope of the present disclosure. The drawings and the description are to be regarded as illustrative in nature and not restrictive, and throughout the specification, the same reference numerals refer to the same elements.
[0035] Recently, due to the increasing energy demand for rechargeable battery modules, the size of the modules has increased. As a result, the size of the flexible printed circuit (FPC) has increased, which may increase the material cost and may weaken the price competitiveness.
[0036] To achieve the price competitiveness of rechargeable battery modules, a low-cost flexible printed circuit that can reduce the material cost of the expensive flexible printed circuit (FPC) is desired. Therefore, it is desirable to simplify the structure of the portion connecting the flexible printed circuit and the bus bar.
[0037] As the size of the module increases, the length of the flexible printed circuit for sensing the voltage and temperature of the cells should be manufactured to be equal to or greater than a set value (1 m). The manufacturing process equipment for flexible printed circuits is at the 500 mm level, so separate equipment is needed to manufacture flexible printed circuits of 1 M or larger size.
[0038] Therefore, the processing cost of the flexible printed circuit increases, and the price of the flexible printed circuit may increase significantly due to the use of expensive copper as a material. In this case, the competitiveness of the rechargeable battery module may be weakened.
[0039] In addition, aluminum foil is a low-cost material that can replace the expensive copper foil in the flexible printed circuit. However, in order to apply aluminum foil, component technologies related to the bonding with sub-components such as temperature sensing elements (NTC) and nickel tabs (Ni-tab) need to be ensured.
[0040] In addition, in order to eliminate the nickel tab (Ni-tab) (which is a connection component for voltage sensing of individual cells through a bus bar), component technologies for directly bonding the bus bar and the flexible printed circuit are required.
[0041] In an embodiment of the rechargeable battery module, since the flexible printed circuit uses aluminum foil, the material cost can be reduced, and since the flexible printed circuit can be directly connected to the bus bar without using a nickel tab, the material cost can be reduced. Hereinafter, the rechargeable battery module of such an embodiment will be described.
[0042] Figure 1 A partial top plan view of a rechargeable battery module according to an embodiment of the present disclosure is shown, Figure 2 showing a top plan view in which a connection portion of a flexible printed circuit is connected to a bus bar applied to Figure 1 a bus bar, Figure 3 showing Figure 2 an enlarged top plan view of a connection portion of a flexible printed circuit for a bus bar in
[0043] Referring to Figures 1 to 3 , the rechargeable battery module according to the embodiment includes a bus bar holder 20 covering a plurality of battery cells 10, a bus bar 30, and a flexible printed circuit (FPC) 40. In one or more embodiments, the battery cell 10 is a rechargeable battery.
[0044] The bus bar holder 20 includes an electrically insulating material and is configured to cover the plurality of battery cells 10 and hold (fix) the position of the bus bar 30 that electrically connects the battery cells 10. The bus bar 30 is on the bus bar holder 20 and electrically connects the battery cells 10 below the bus bar holder 20.
[0045] The flexible printed circuit (FPC) 40 is configured to detect the temperature of the bus bar 30 and the voltage of the battery cell 10 and transmit the temperature and voltage to the battery management system (BMS). In one or more embodiments, the flexible printed circuit 40 is mounted with a temperature sensor that is covered with an insulating material to be electrically insulated and physically (directly or indirectly) contacts one or more of the battery cells 10 to detect the temperature of the battery cells 10.
[0046] The flexible printed circuit (FPC) 40 is on the bus bar holder 20 and connected to the bus bar 30. The FPC 40 is formed by coating both surfaces of the circuit pattern with a film, and the FPC 40 is configured to transmit a signal of the voltage of the battery cell 10 sensed through the bus bar 30. In one or more embodiments, the flexible printed circuit (FPC) 40 is directly connected to the bus bar 30.
[0047] In one or more embodiments, the bus bar 30 further includes cell connection portions 31 and 32 connected to adjacent battery cells 10 and an extension portion 33 protruding from one of the cell connection portions 31 and 32 to one side, as Figure 2 shown.
[0048] The flexible printed circuit 40 includes a branch portion 42 (see Figure 5 ) and an extension portion 43. The branch portion 42 extends from a main body portion 41 connected to the battery management system and has a width narrower than the width of the main body portion 41. The extension portion 43 has an enlarged area in the branch portion 42. The extension portion 43 is connected to the extension portion 33 of the bus bar 30, for example, by a soldering joint.
[0049] Although the branch portion 42 has a narrow width and a small area, the extension portion 43 is enlarged and has a width wider than that of the branch portion 42 and an area larger than that of the branch portion 42. Therefore, the extension portion 43 and the extension portion 33 can be firmly joined (for example, soldered together).
[0050] Figure 4 Shown Figures 1 to 3 is a plan view of the connection portion of the flexible printed circuit shown in Figure 5 shown is an image of the connection portion of the flexible printed circuit joined to the bus bar according to the embodiment shown in Figure 1 .
[0051] Referring to Figures 2 to 5 , the extension portion 43 includes a plurality of through holes 431 penetrating through the foil connected to the circuit pattern, a soldering pattern 433 formed by removing the coating of the film 432 from the outside of the through holes 431, and a soldering portion 434 joining the extension portion 33 exposed through the through holes 431 and the soldering pattern 433.
[0052] The foil can be made of copper or aluminum. The via holes 431 extend through the foil and allow the solder melted by the laser during welding to be joined to the extension portion 33 through the via holes 431. During the manufacturing process, the wire solder is supplied onto each via hole 431 and melted by the laser LS irradiated onto the via hole 431.
[0053] The welding pattern 433 includes a copper or aluminum foil. A part of the solder melted by the laser LS reaches the extension portion 33 through the via hole 431 and is joined to the extension portion 33, and the remaining part is joined to the welding pattern 433. That is, the welding portion 434 connects the extension portion 33 of the bus bar 30 and the welding pattern 433 of the flexible printed circuit 40 to each other.
[0054] Therefore, the bus bar 30 electrically connected to the battery cell 10 detects the voltage of the battery cell 10 and transmits the voltage of the battery cell 10 to the flexible printed circuit 40 through the welding pattern 433 of the extension portion 33 and the extension portion 43.
[0055] In one or more embodiments, the film 432 can include polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) having a low heat-resistant temperature to reduce the material cost.
[0056] In Figure 4 In the illustrated embodiment, a plurality of via holes 431 are arranged in the width direction (y-axis direction) and the length direction (x-axis direction) of the extension portion 43 (for example, the via holes 431 are arranged in rows and columns). In one or more embodiments, four via holes 431 are arranged in a grid having two rows in the width direction and two columns in the length direction.
[0057] As Figure 3 shown, when the wire solder is supplied from left to right, the welding and joining by irradiating the laser LS are sequentially performed from the upper right via hole 431 to the lower right via hole 431, from the lower right via hole 431 to the lower left via hole 431, and from the lower left via hole 431 to the upper left via hole 431. This laser (LS) irradiation process does not prevent the laser (LS) irradiation due to the wire solder.
[0058] Returning to Figure 4, the extension part 43 has an area (L1 * W1) defined by a first length L1 in the longitudinal direction (x-axis direction) of the branch part 42 and a first width W1 in the width direction (y-axis direction) intersecting the longitudinal direction. The area (L1 * W1) of the extension part 43 is configured to achieve a desired peel strength and resistance value when the extension part 43 is welded to the extension part 33 of the bus bar 30. In one or more embodiments, when the width W0 of the branch part 42 is about 3 mm, the first length L1 of the extension part 43 can be about 12 mm and the first width W1 of the extension part 43 can be about 11 mm. The flexible printed circuit 40 may further include a rounded corner where the branch part 42 and the extension part 43 are connected. The rounded corner may have a curvature radius R1.
[0059] Each through hole 431 has a slotted hole structure having a hole width WH in the width direction (y-axis direction) and a hole length LH in the longitudinal direction (x-axis direction). By forming the hole length LH longer than the hole width WH, sufficient peel strength can be ensured in the longitudinal direction in the welded joint state. In one or more embodiments, in each through hole 431, the hole length LH can be about 2.4 mm and the hole width WH can be about 1 mm.
[0060] The welding pattern 433 includes: a pattern width part having a pattern width WP (which has substantially the same size as the hole width WH) in the width direction (y-axis direction) and on both sides of the through hole 431 in the width direction (y-axis direction); and a pattern length part having a pattern length LP in the longitudinal direction (x-axis direction), connected to both sides of the pattern width part in the longitudinal direction (x-axis direction) and having a smaller curvature (e.g., a larger radius of curvature) than the bent end of the through hole 431. Since the pattern width part is formed to have a larger area than the pattern length part, when the linear solder is melted and joined by irradiating the center of the through hole 431 with the laser LS, damage to the film 432 is prevented (or at least mitigated) while sufficiently ensuring the area of the welded part 434. In one or more embodiments, the pattern width WP can be about 1.5 mm and the pattern length LP can be about 0.5 mm.
[0061] In addition, the extension portion 43 includes an 11th inner coating portion F11 and a 12th outer coating portion F12 in the width direction (y-axis direction). The 11th inner coating portion F11 is between the welding patterns 433 in the width direction (y-axis direction) and is the area of the foil coated with the film 432. The 12th outer coating portion F12 is the area outside the welding patterns 433 in the width direction (y-axis direction) and is the area of the foil coated with the film 432. The 11th inner coating portion F11 has a size that is substantially equal to twice the size of the 12th outer coating portion F12. The welding patterns 433 and the welding portions 434 provide the peel strength, and the 11th inner coating portion F11 and the 12th outer coating portion F12 provide the durability of the extension portion 43 in their respective areas, thereby preventing a reduction in the peel strength. Therefore, the peel strength between the extension portion 43 and the extension portion 33 is set by the welding patterns 433 and the welding portions 434. In one or more embodiments, the 11th inner coating portion F11 may be about 2 mm, and the 12th outer coating portion F12 may be about 1 mm.
[0062] In addition, the extension portion 43 includes a first recessed portion C1 in each 12th outer coating portion F12. The first recessed portion C1 is configured to absorb the tension applied in the length direction (x-axis direction) in the welded joint state and is configured to cause deformation, thereby further ensuring the peel strength of the entire extension portion 43.
[0063] In addition, the extension portion 43 includes a 21st inner coating portion F21 and a 22nd outer coating portion F22 in the length direction (x-axis direction). The 21st inner coating portion F21 is between the welding patterns 433 in the length direction (x-axis direction) and is the area of the foil coated with the film 432. The 22nd outer coating portion F22 is the area outside the welding patterns 433 in the length direction (x-axis direction) and is the area of the foil coated with the film 432. The 21st inner coating portion F21 has a size similar to (e.g., substantially equal to) the size of the 22nd outer coating portion F22. The welding patterns 433 and the welding portions 434 provide the peel strength, and the 21st inner coating portion F21 and the 22nd outer coating portion F22 provide the durability of the extension portion 43 in their respective areas, thereby preventing a reduction in the peel strength. Therefore, the peel strength between the extension portion 43 and the extension portion 33 is set by the welding patterns 433 and the welding portions 434. In one or more embodiments, the 21st inner coating portion F21 may be about 1.6 mm and the 22nd outer coating portion F22 may be about 1.8 mm.
[0064] In addition, the extension portion 43 includes second recessed portions C2 in each of the 22nd outer coating portions F22. The second recessed portions C2 are configured to absorb the tension that intersects with the tension applied in the longitudinal direction (x-axis direction) in the welded joint state and are configured to cause deformation, thereby further ensuring the peel strength of the entire extension portion 43.
[0065] Hereinafter, various experimental examples will be described. Figure 6 Images showing a first experimental example and a second experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure, Figure 7 Images showing a third experimental example and a fourth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure, Figure 8 Images showing a fifth experimental example and a sixth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure, Figure 9 Images showing a seventh experimental example and an eighth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure, Figure 10 Images showing a ninth experimental example and a tenth experimental example in which a connection portion of a flexible printed circuit is connected to a bus bar according to an embodiment of the present disclosure.
[0066] Refer to Figures 6 to 10 , during the manufacturing process, the power of the laser irradiated on the linear solder is about 70 W, the preheating temperature of the extension portion 33 of the bus bar 30 is about 240 °C, and the entire process time takes about 25 seconds. After the first preheating, linear solder supply, second preheating, linear solder supply, third preheating, linear solder supply, and fourth preheating, the extension portion 43 is welded and joined to the extension portion 33 by a laser welding process. As a result, the first to tenth experimental examples as shown in Figures 6 to 10 are obtained.
[0067] As shown in Table 1 below, in the first to tenth experimental examples, the resistance values of the extension portion 43 and the extension portion 33 joined to each other by laser welding are in the range of from about 2.5 mΩ to about 3.5 mΩ.
[0068] Table 1
[0069]
[0070] The results in Table 1 show that even when the extension portion 43 of the flexible printed circuit 40 and the extension portion 33 of the bus bar 30 are directly joined together, the resistance value is in the range of from about 2.5 mΩ to about 3.5 mΩ, which is lower than the required minimum resistance value of about 5 mΩ. Therefore, even if the nickel tab (Ni-tab) connecting the FPC to the bus bar is omitted, the voltage of the battery cell 10 can be detected.
[0071] As shown in Table 2, in the first to fifth experimental examples, the peel strength (without bonding) between the extended portion 43 and the extended portion 33 joined by laser welding is in the range from about 8.41 N to about 11.72 N (average about 9.71 N).
[0072] Table 2
[0073]
[0074] The results in Table 2 show that even when the extended portion 43 of the flexible printed circuit 40 and the extended portion 33 of the bus bar 30 are directly joined together, the peel strength is in the range from about 8.41 N to about 11.72 N, which is higher than the required minimum peel strength of 5 N. Therefore, even if the nickel tab (Ni-tab) connecting the FPC to the bus bar is omitted, the peel strength can be maintained.
[0075] Although the present invention has been described in connection with presently considered practical exemplary embodiments, it will be understood that the present invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
[0076] Description of Reference Numerals
[0077] 10: Battery cell 20: Bus bar holder
[0078] 30: Bus bar 31, 32: Cell connection portions
[0079] 33: Extended portion 40: Flexible printed circuit (FPC)
[0080] 41: Main body portion 42: Branch portion
[0081] 43: Extended portion 431: Through hole
[0082] 432: Film 433: Welding pattern
[0083] 434: Welded portion C1: First recessed portion
[0084] C2: Second recessed portion F11: 11th inner coating portion
[0085] F12: 12th outer coating portion
[0086] F21: 21st inner coating portion
[0087] F22: 22nd outer coating portion
[0088] L1: First length
[0089] LH: Hole length LP: Pattern length
[0090] LS: Laser W0: Width
[0091] W1: First width WH: Hole width
[0092] WP: Pattern width.
Claims
1. A rechargeable battery module, comprising: A bus bar holder covering a plurality of battery cells; A bus bar on the bus bar holder, the bus bar electrically connecting the plurality of battery cells; And A flexible printed circuit on the bus bar holder, the flexible printed circuit including a film with circuit patterns coated on two surfaces, the flexible printed circuit configured to transmit signals for detecting the voltages of the battery cells among the plurality of battery cells connected to the bus bar, Wherein the bus bar includes an extension portion protruding in one direction, Wherein the flexible printed circuit includes a main body portion, a branch portion extending from the main body portion, and an extension portion welded to the extension portion, the extension portion having an area larger than that of the branch portion.
2. The rechargeable battery module according to claim 1, wherein the extension portion includes: At least one through hole penetrating a foil connected to the circuit pattern, At least one welding pattern exposed by an opening in the film around the at least one through hole, and A welding portion joining the extension portion exposed through the at least one through hole to the at least one welding pattern.
3. The rechargeable battery module according to claim 2, wherein the foil includes copper or aluminum.
4. The rechargeable battery module according to claim 2, wherein the extension portion has an area defined by a first length in the length direction of the branch portion and a first width in the width direction intersecting the length direction.
5. The rechargeable battery module according to claim 4, wherein the branch portion is at the outermost side of the extension portion in the width direction, the branch portion having a width smaller than the first width of the extension portion, and wherein the branch portion extends in the length direction.
6. The rechargeable battery module according to claim 5, wherein the flexible printed circuit further includes a rounded corner where the branch portion and the extension portion are connected.
7. The rechargeable battery module according to claim 2, wherein the at least one through hole includes a plurality of through holes arranged in the width direction and the length direction of the branch portion.
8. The rechargeable battery module according to claim 4, wherein the at least one through hole includes a plurality of through holes, two of the plurality of through holes are arranged in the width direction, and another two of the plurality of through holes are arranged in the length direction.
9. The rechargeable battery module according to claim 8, wherein each of the plurality of through holes has a slot hole structure, the slot hole structure having a hole width in the width direction and a hole length in the length direction.
10. The rechargeable battery module according to claim 9, wherein the at least one welding pattern includes a plurality of welding patterns, and each of the plurality of welding patterns includes: A pattern width portion on both sides in the width direction of each of the plurality of through holes and having the same size as the hole width, and A pattern length portion is connected to both sides of the pattern width portion in the length direction, and the pattern length portion has a radius of curvature larger than that of each of the slot hole structures of the plurality of through holes.
11. The rechargeable battery module according to claim 8, wherein the extension portion includes: An 11th inner coating portion is between two of the plurality of welding patterns in the width direction, and the 11th inner coating portion includes a portion of the foil coated with the film, and A 12th outer coating portion is outside the two welding patterns in the width direction, and the 12th outer coating portion includes another portion of the foil coated with the film, and wherein the 11th inner coating portion has a size equal to twice the size of the 12th outer coating portion.
12. The rechargeable battery module according to claim 11, wherein the extension portion includes a first recessed portion in the 12th outer coating portion.
13. The rechargeable battery module according to claim 8, wherein the extension portion includes: A 21st inner coating portion is between two of the plurality of welding patterns in the length direction, and the 21st inner coating portion includes a portion of the foil coated with the film, and A 22nd outer coating portion is outside the two welding patterns in the length direction, and the 22nd outer coating portion includes another portion of the foil coated with the film, and the 21st inner coating portion has a size smaller than or equal to the size of the 22nd outer coating portion.
14. The rechargeable battery module according to claim 13, wherein the extension portion includes a second recessed portion in the 22nd outer coating portion.
15. The rechargeable battery module according to claim 2, wherein the welding portion electrically connects the at least one welding pattern to the extension portion exposed through the at least one through hole.