Battery cell including electrode tabs with wire breakage prevention function and battery module including the same

Abstract

The present invention relates to a battery cell including an electrode tab with a breakage prevention function and a battery module including the same, and more particularly, to a battery cell including an electrode tab with a breakage prevention function, the battery cell including the battery module including the same, the battery cell including the electrode tab with a breakage prevention function comprising: a case having a laminate sheet structure; an electrode assembly housed inside the case; an electrode tab located on a side of the electrode assembly; an electrode lead having one side connected to the electrode tab and the other side protruding out of the case; and insulating films provided on upper and lower surfaces of the electrode lead, the electrode tab having a buffer portion whose length is adjustable.

Description

[Technical Field]

[0001] This application claims priority under Korean Patent Application No. 2022-0047082 dated April 15, 2022, and all content disclosed in said Korean Patent Application is incorporated herein as part of this specification.

[0002] The present invention relates to a battery cell including an electrode tab with a wire breakage prevention function and a battery module including the same. Specifically, the present invention relates to a battery cell including an electrode tab with a wire breakage prevention function that prevents the electrode tab from breaking due to movement of the electrode assembly or external impact, by providing the electrode tab with a wire breakage prevention function. [Background technology]

[0003] Recently, there has been increasing demand for rechargeable batteries that can store electrical energy produced by air pollution caused by the use of fossil fuels and the development of alternative energy sources due to energy depletion. Rechargeable batteries are closely used in daily life, such as in mobile devices, electric vehicles, and hybrid electric vehicles.

[0004] Rechargeable batteries, which are used as an energy source for various electronic devices that are indispensable in modern society, are seeing increased capacity requirements due to the growing usage and complexity of mobile devices and the development of electric vehicles. To meet user demand, small devices have a large number of battery cells, while automobiles and other large vehicles use battery modules in which many battery cells are electrically connected, or battery packs that contain many such battery modules.

[0005] On the other hand, battery cells are used in electric vehicles and smartphones, among other things. In these applications, tension can be generated between the electrode tab and electrode lead due to movement caused by external shock or the swelling phenomenon that occurs during charging and discharging, which can lead to disconnection.

[0006] Figure 1 is a cross-sectional view of a conventional battery cell. As shown in Figure 1, the conventional battery cell includes an electrode assembly 10, an electrode tab 20 extending to one side of the electrode assembly 10, a buffer portion 30 formed on the electrode tab 20, and an electrode lead 40, one end of which is connected to the electrode tab 20 and the other end of which protrudes to the outside of the case.

[0007] In conventional battery cells, when tension is generated in the electrode tab 20 due to the swelling phenomenon or the like, a bent-shaped buffer portion 30 provided on the electrode tab 20 relaxes and reduces the tension, thereby preventing the electrode tab 20 from breaking.

[0008] However, since the buffer portion 30 of the electrode tab 20 has a bent shape, it leads to an increase in the volume of the battery cell, resulting in a problem of lower energy density.

[0009] Furthermore, since the overall length of the electrode tab 20 increases, this can lead to increased resistance and higher manufacturing costs. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Korean Published Patent Publication No. 2019-0067312 [Overview of the project] [Problems that the invention aims to solve]

[0011] To solve the aforementioned problems, the present invention aims to provide a battery cell and a battery module including the same that can prevent the electrode tabs and electrode leads from breaking even if the electrode assembly becomes loose or a swelling phenomenon occurs due to external vibrations or shocks.

[0012] Furthermore, the present invention aims to provide a battery cell and a battery module including the same that can prevent disconnection of the electrode tabs and electrode leads without increasing the volume of the battery cell or increasing material costs. [Means for solving the problem]

[0013] To achieve the above objectives, the battery cell according to the present invention, which includes an electrode tab with a wire breakage prevention function, comprises a case (100) having a laminate sheet structure, an electrode assembly (200) housed inside the case (100), an electrode tab (300) located on the side of the electrode assembly (200), an electrode lead (400) one end of which is connected to the electrode tab (300) and the other end protruding to the outside of the case (100), and insulating films (500) provided on the upper and lower surfaces of the electrode lead (400), wherein the electrode tab (300) is provided with a length-adjustable buffer portion (310).

[0014] Furthermore, in the battery cell according to the present invention, the buffer portion (310) is characterized in that it is located between the connecting portion W of the electrode tab (300) and the electrode assembly (200).

[0015] Furthermore, in the battery cell according to the present invention, the buffer portion (310) is characterized in that a plurality of zigzag-shaped first break lines (311) are formed along the longitudinal direction of the electrode tab (300).

[0016] Furthermore, in the battery cell according to the present invention, the buffer portion (310) is characterized in that a plurality of first broken lines (311) of the waveform are formed along the longitudinal direction of the electrode tab (300).

[0017] Furthermore, in the battery cell according to the present invention, the buffer portion (310) is characterized in that a plurality of zigzag-shaped incision lines (313) are formed along the longitudinal direction of the electrode tab (300).

[0018] Furthermore, in the battery cell according to the present invention, the buffer portion (310) is characterized in that a plurality of waveform cutting lines (313) are formed along the longitudinal direction of the electrode tab (300).

[0019] Further, in the battery cell according to the present invention, second breaking lines (312) are formed on both side edges in the width direction of the buffer portion (310).

[0020] Further, in the battery cell according to the present invention, a part of both side edges in the width direction of the buffer portion (310) is cut in a zigzag shape, and a plurality of zigzag first breaking lines (311) are formed along the longitudinal direction of the electrode tab (300).

[0021] Further, in the battery cell according to the present invention, a part of both side edges in the width direction of the buffer portion (310) is cut in a waveform shape, and a plurality of waveform first breaking lines (311) are formed along the longitudinal direction of the electrode tab (300).

[0022] Further, in the battery cell according to the present invention, a part of both side edges in the width direction of the buffer portion (310) is cut in a zigzag shape, and a plurality of zigzag cutting lines (313) are formed along the longitudinal direction of the electrode tab (300).

[0023] Further, in the battery cell according to the present invention, a part of both side edges in the width direction of the buffer portion (310) is cut in a waveform shape, and a plurality of waveform cutting lines (313) are formed along the longitudinal direction of the electrode tab (300).

[0024] Further, in the battery cell according to the present invention, the buffer portion (310) is positioned so as not to overlap on a perpendicular line with the insulating film (500).

[0025] Further, the present invention can be a battery module including the battery cell having the above-described features.

[0026] Further, the present invention can be a battery pack including the above-described battery module.

Effects of the Invention

[0027] As described above, the battery cell according to the present invention has the advantage that, by forming a buffer portion consisting of a broken line or a cut line in a part of the electrode tab, it is possible to prevent the electrode tab and electrode lead from breaking even if the electrode assembly becomes loose or a swelling phenomenon occurs.

[0028] Furthermore, since the buffer portion of the battery cell according to the present invention consists of a fractured line or an incised line, the volume of the battery cell does not increase, and thus it is possible to prevent a decrease in energy density, which is an advantage.

[0029] Furthermore, since the buffer portion of the battery cell according to the present invention consists of a broken line or an incised line, the length of the electrode tab does not increase, which has the advantage of suppressing an increase in material costs. [Brief explanation of the drawing]

[0030] [Figure 1] This is a cross-sectional view of a battery cell using conventional technology. [Figure 2] This is an exploded perspective view of a battery cell according to a preferred first embodiment of the present invention. [Figure 3] This is an enlarged perspective view of an electrode tab according to a preferred first embodiment of the present invention. [Figure 4] This is an enlarged perspective view of an electrode tab according to a preferred second embodiment of the present invention. [Figure 5] This is an enlarged perspective view of an electrode tab according to a preferred third embodiment of the present invention. [Figure 6] This is an enlarged perspective view of an electrode tab according to a preferred fourth embodiment of the present invention. [Figure 7] This is an enlarged perspective view of an electrode tab according to a preferred fifth embodiment of the present invention. [Figure 8] This is an enlarged perspective view of an electrode tab according to a preferred sixth embodiment of the present invention. [Figure 9] This is an enlarged perspective view of an electrode tab according to a preferred seventh embodiment of the present invention. [Figure 10] This is an enlarged perspective view of an electrode tab according to a preferred eighth embodiment of the present invention. [Modes for carrying out the invention]

[0031] Hereinafter, embodiments that allow a person with ordinary skill in the art to carry out the present invention will be described in detail based on the attached drawings. However, in describing the operating principles of preferred embodiments of the present invention in detail, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0032] Furthermore, the same reference numerals shall be used throughout the drawings for parts that have similar functions and operations. Throughout the specification, when it is said that one part is connected to another part, this includes not only direct connections but also indirect connections through other elements in between. Also, when it is said that a component is included, unless otherwise stated, it does not mean that other components are excluded, but rather that other components may be included.

[0033] Hereinafter, a battery cell including an electrode tab with a wire breakage prevention function according to the present invention and a battery module including the same will be described with reference to the attached drawings.

[0034] Figure 2 is an exploded perspective view of a battery cell according to a preferred first embodiment of the present invention, and Figure 3 is an enlarged perspective view of an electrode tab according to a preferred first embodiment of the present invention.

[0035] As shown in Figures 2 and 3, the battery cell according to the present invention comprises a case 100, an electrode assembly 200, an electrode tab 300, an electrode lead 400, and an insulating film 500.

[0036] First, the case 100 can consist of an upper case and a lower case, and a pocket-shaped storage section is formed so that the electrode assembly 200 can be stored inside.

[0037] In such a case 100, the storage compartment is formed using a laminate sheet consisting of an outer resin layer 110, a metal layer 120, and an inner resin layer 130.

[0038] The outer resin layer 110 is located on the outer casing of the case 100, and such an outer resin layer 110 can be made of a heat-resistant polymer with excellent tensile strength, moisture resistance, and air resistance so as to protect the electrode assembly 200 while ensuring heat resistance and chemical resistance. For example, nylon or polyethylene terephthalate can be used, but is not limited thereto.

[0039] The metal layer 120 in contact with the outer resin layer 110 acts as a barrier layer that prevents moisture and various gases from penetrating into the battery from the outside. A preferred material for such a metal layer is a thin aluminum film that is lightweight yet has excellent moldability.

[0040] Furthermore, since the internal resin layer 130 is in direct contact with the electrode assembly 200, it must have insulating and electrolytic resistance properties. In addition, for sealing to the outside, it must have sealing properties, meaning that the sealing portions where the internal layers are heat-bonded together must have excellent thermal bonding strength.

[0041] The material for such an internal resin layer 130 can be selected from, but is not limited to, polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, polyurethane resins, and polyimide resins, which have excellent chemical resistance and good sealing properties. Polypropylene is most preferred because it has excellent mechanical properties such as tensile strength, rigidity, surface hardness, and impact strength, as well as excellent chemical resistance.

[0042] The electrode assembly 100 housed in the case 100 can be composed of, but is not limited to, a jelly roll type electrode assembly having a structure in which a separator is interposed between a long sheet-like negative electrode and a positive electrode and then wound, a stack type electrode assembly composed of unit cells having a structure in which rectangular positive and negative electrodes are laminated with a separator interposed therebetween, a stack-folding type electrode assembly in which unit cells are wound by a long separation film, or a lamination-stack type electrode assembly in which unit cells are laminated with a separator interposed therebetween and adhered to each other.

[0043] Specifically, the negative electrode is manufactured by applying a slurry in which a negative electrode active material and a binder are mixed to a negative electrode current collector.

[0044] Here, examples of the negative electrode active material include carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8) and other metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; Si-based materials that are Si, SiO, SiO2 alone or mixtures thereof, etc. can be used, but are not limited to only these.

[0045] The positive electrode is manufactured by applying a slurry in which a positive electrode active material and a binder are mixed to a positive electrode current collector.

[0046] As the positive electrode active material, there are layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x O4 (where x is 0 to 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3), Ni-site type lithium nickel oxides represented by this formula; chemical formula LiMn 2-x M x O2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or lithium manganese composite oxides represented by Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); LiMn2O4 in which part of the Li in the chemical formula is substituted with alkaline earth metal ions; disulfide compounds; Fe2(MoO4)3 and the like can be mentioned, but it is not limited only to these.

[0047] On the other hand, the negative electrode current collector and the positive electrode current collector are composed of a portion where a slurry mixed with an active material is applied and a plain portion where the slurry is not applied, and the electrode tab 300 is formed by cutting the plain portion or connecting a separate conductive member to the plain portion by ultrasonic welding or the like.

[0048] An electrode lead 400 is connected to such an electrode tab 300 by spot welding or the like, and an insulating film 500 is located around the electrode lead 400.

[0049] In order to minimize the tension transmitted to the electrode tab 300 even when a floating or swelling phenomenon of the electrode assembly due to an external impact occurs, the electrode tab 300 is provided with a buffer portion 310 whose length can be adjusted.

[0050] It is preferable that such a buffer portion 310 is located between the connecting portion W of the electrode tab 300 and the electrode assembly 200, and that it does not overlap with the insulating film 500 on a vertical line, that is, that the insulating film 500 is not located above or below the buffer portion 310. If the buffer portion 310 and the insulating film 500 are arranged to overlap, even if tension is generated in the electrode tab 300 due to a swelling phenomenon or the like, the buffer portion 310 will not be stretched properly and will not be able to fully exert its wire breakage suppression effect.

[0051] To describe the buffer portion 310 in more detail, the buffer portion 310 is designed to reduce tension in the electrode tab 300 by partially breaking and relaxing when tension is generated in the tab, and multiple zigzag-shaped first break lines 311 may be formed.

[0052] The zigzag-shaped first fracture line 311 is a dotted line pattern in which a portion is cut along the longitudinal direction (X-axis direction) of the electrode tab 300, that is, a shape in which a portion is cut at predetermined intervals. When tension is generated in the electrode tab 300 due to movement or swelling of the electrode assembly 200, the portion of the first fracture line 311 that was not cut breaks, and the buffer portion 310 relaxes, thereby preventing the electrode tab 300 from being completely cut.

[0053] Furthermore, it is preferable that the buffer portion 310 is further provided with second break lines 312 on both side edges in the width direction (Y-axis direction) of the buffer portion 310.

[0054] The second fracture line 312 may have a dotted line pattern with a portion being cut, similar to the first fracture line 311, and is preferably provided on the first fracture line 311 located on the outermost edges of the zigzag-shaped plurality of first fracture lines 311, and more preferably on the portion that is as close as possible to the edge of the electrode tab 300.

[0055] The purpose of this second break wire 312 is to protect the electrode tab 300 from breaking under normal circumstances, and to allow the first break wire 311 to be easily stretched when tension is generated in the electrode tab 300, by causing both side edges of the buffer portion 310 to break.

[0056] Next, the insulating film 500 is positioned above and below the sealing portion where the lower case and the upper case are heat-fused, and more specifically above and below the connection portion W between the electrode tab 300 and the electrode lead 400, respectively, to prevent short circuits.

[0057] Here, the insulating film 500 is preferably made of a non-conductive material that does not conduct electricity well, and generally, insulating tape that adheres easily to the electrode lead 400 and is relatively thin is often used, but it is not limited to this.

[0058] Specifically, the insulating film 500 may consist of one or more substances selected from the group consisting of polyimide (PI), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and epoxy resin.

[0059] Figure 4 is an enlarged perspective view of the electrode tab according to a preferred second embodiment of the present invention. Referring to Figure 4, the battery cell according to the second embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0060] In a battery cell according to a preferred second embodiment of the present invention, the first broken line 311 of the buffer portion 310 has a waveform.

[0061] Furthermore, it is preferable that the second break line 312 is provided on the outermost first break line 311 on both sides of the plurality of first break lines 311 having a waveform, and it is more preferable that it is provided so as to be connected to the edge of the electrode tab 300 at the portion that is as close as possible to the edge of the electrode tab 300.

[0062] Figure 5 is an enlarged perspective view of the electrode tab according to a preferred third embodiment of the present invention. Referring to Figure 5, the battery cell according to the preferred third embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0063] In a battery cell according to a preferred third embodiment of the present invention, the buffer portion 310 has a plurality of zigzag-shaped, completely cut incisions 313 formed therein. Of the plurality of incisions 313, the incisions 313 located on the outermost edges on both sides are provided with second break lines 312.

[0064] Thus, the battery cell according to the third embodiment has the advantage that when tension is generated in the electrode tab 300, the second break line 312 can be relaxed more quickly when it breaks.

[0065] Figure 6 is an enlarged perspective view of the electrode tab according to a preferred fourth embodiment of the present invention. Referring to Figure 6, the battery cell according to the preferred fourth embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0066] In a battery cell according to a preferred fourth embodiment of the present invention, the buffer portion 310 has a plurality of completely cut incisions 313 having a wavy shape. Of the plurality of incisions 313, the incisions 313 located on the outermost edges on both sides are provided with second break lines 312.

[0067] Thus, the battery cell according to the fourth embodiment has the advantage that when tension is generated in the electrode tab 300, the second break line 312 can be relaxed more quickly when it breaks.

[0068] Figure 7 is an enlarged perspective view of the electrode tab according to a preferred fifth embodiment of the present invention. Referring to Figure 7, the battery cell according to the preferred fifth embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0069] In a battery cell according to a preferred fifth embodiment of the present invention, the buffer portion 310 has a portion of both side edges in the width direction (Y-axis direction) cut in a zigzag shape, and a plurality of zigzag-shaped first fracture lines 311 are formed along the longitudinal direction (X-axis direction) of the electrode tab 300.

[0070] Figure 8 is an enlarged perspective view of the electrode tab according to a preferred sixth embodiment of the present invention. Referring to Figure 8, the battery cell according to the preferred sixth embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0071] In a battery cell according to a preferred sixth embodiment of the present invention, the buffer portion 310 has a portion of both side edges in the width direction (Y-axis direction) cut into a wave shape, and a plurality of wave-shaped first break lines 311 are formed along the longitudinal direction (X-axis direction) of the electrode tab 300.

[0072] Figure 9 is an enlarged perspective view of the electrode tab according to a preferred seventh embodiment of the present invention. Referring to Figure 9, the battery cell according to the preferred seventh embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0073] In a battery cell according to a preferred seventh embodiment of the present invention, the buffer portion 310 has a portion of both side edges in the width direction (Y-axis direction) cut in a zigzag shape, and multiple zigzag cut lines 313 are formed along the longitudinal direction (X-axis direction) of the electrode tab 300.

[0074] Thus, since the buffer portion 310 according to the seventh embodiment consists only of a plurality of incision lines 313, it has the advantage that it can be stretched very quickly when tension is generated in the electrode tab 300.

[0075] Figure 10 is an enlarged perspective view of the electrode tab according to a preferred eighth embodiment of the present invention. Referring to Figure 10, the battery cell according to the preferred eighth embodiment of the present invention is identical to that of the first embodiment described in Figures 2 and 3, except for the shape of the buffer portion 310, so a description of the same configuration will be omitted.

[0076] In a battery cell according to a preferred eighth embodiment of the present invention, the buffer portion 310 has a portion of both side edges in the width direction (Y-axis direction) cut in a wave shape, and multiple wave-shaped cut lines 313 are formed along the longitudinal direction (X-axis direction) of the electrode tab 300.

[0077] Thus, since the buffer portion 310 according to the eighth embodiment consists only of a plurality of incision lines 313, it has the advantage that it can be stretched very quickly when tension is generated in the electrode tab 300.

[0078] Furthermore, the present invention may be a battery module including the aforementioned battery cells, or a battery pack including the battery module described above.

[0079] A person with ordinary skill in the field to which this invention belongs will be able to make various applications and modifications within the scope of this invention based on the above content. [Explanation of symbols]

[0080] 100 cases 110 Outer resin layer 120 metal layer 130 Internal resin layer 200 electrode assembly 300 electrode tabs 310 Buffer section 311 First Fracture Line 312 Second Fracture Line 313 Incision Line 400 electrode leads 500 insulating film W connection part

Claims

1. A case having a laminate sheet structure, The electrode assembly housed inside the aforementioned case, An electrode tab located on the side of the electrode assembly, One end of the electrode lead is connected to the electrode tab, and the other end of the electrode lead protrudes to the outside of the case. The electrode leads include insulating films provided on the upper and lower surfaces, The electrode tab is provided with a buffer portion whose length can be adjusted. The buffer portion has multiple zigzag-shaped first fracture lines formed along the longitudinal direction of the electrode tab, and the zigzag-shaped first fracture lines are lines having a dotted line pattern in which a portion is cut at predetermined intervals. A battery cell in which a second fracture line is formed in the buffer portion, connecting from both side edges in the width direction of the buffer portion to the first fracture line located at the outermost edge on both sides of the plurality of first fracture lines.

2. A case having a laminate sheet structure, The electrode assembly housed inside the aforementioned case, An electrode tab located on the side of the electrode assembly, One end of the electrode lead is connected to the electrode tab, and the other end of the electrode lead protrudes to the outside of the case. The electrode leads include insulating films provided on the upper and lower surfaces, The electrode tab is provided with a buffer portion whose length can be adjusted. The buffer portion has multiple first break lines of the waveform formed along the longitudinal direction of the electrode tab, and the first break lines of the waveform are lines having a dotted line pattern in which a portion is cut at predetermined intervals. A battery cell in which a second fracture line is formed in the buffer portion, connecting from both side edges in the width direction of the buffer portion to the first fracture line located at the outermost edge on both sides of the plurality of first fracture lines.

3. A case having a laminate sheet structure, The electrode assembly housed inside the aforementioned case, An electrode tab located on the side of the electrode assembly, One end of the electrode lead is connected to the electrode tab, and the other end of the electrode lead protrudes to the outside of the case. The electrode leads include insulating films provided on the upper and lower surfaces, The electrode tab is provided with a buffer portion whose length can be adjusted. The buffer portion has multiple zigzag-shaped incisions formed along the longitudinal direction of the electrode tab, and these zigzag-shaped incisions are completely cut lines. A battery cell in which a second fracture line is formed in the buffer portion, extending from both side edges in the width direction of the buffer portion and connecting to the outermost incision lines on both sides of the plurality of incision lines.

4. A case having a laminate sheet structure, The electrode assembly housed inside the aforementioned case, An electrode tab located on the side of the electrode assembly, One end of the electrode lead is connected to the electrode tab, and the other end of the electrode lead protrudes to the outside of the case. The electrode leads include insulating films provided on the upper and lower surfaces, The electrode tab is provided with a buffer portion whose length can be adjusted. The buffer portion has multiple waveform incision lines formed along the longitudinal direction of the electrode tab, and these waveform incision lines are completely cut lines. A battery cell in which a second fracture line is formed in the buffer portion, extending from both side edges in the width direction of the buffer portion and connecting to the outermost incision lines on both sides of the plurality of incision lines.

5. The battery cell according to any one of claims 1 to 4, wherein the buffer portion is located between the connecting portion of the electrode tab and the electrode assembly.

6. The battery cell according to claim 5, wherein the buffer portion is positioned so as not to overlap with the insulating film on a perpendicular line.

7. A battery module comprising a battery cell according to any one of claims 1 to 4.

8. A battery pack comprising the battery module described in claim 7.

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