Battery cell and battery cell manufacturing device

Abstract

According to one aspect of the present invention, a battery cell includes a battery case including a receiving portion in which an electrode assembly is mounted and a sealing portion formed by sealing the outer periphery of the receiving portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing portion; and a lead film located at a portion corresponding to the sealing portion on at least one of an upper part and a lower part of the electrode lead, the lead film including a first stepped portion protruding in a direction opposite to the electrode lead side, the sealing portion including a second stepped portion covering an outer surface of the first stepped portion, and a gas discharge guide portion inserted within the first stepped portion.

Description

[Technical field]

[0001] The present invention relates to a battery cell and a battery cell manufacturing apparatus for manufacturing the same, and more specifically, to a battery cell having improved sealing strength and safety and improved ability to discharge gas generated inside the battery cell to the outside, and a battery cell manufacturing apparatus for manufacturing the same. This application claims priority based on Korean Patent Application No. 10-2021-0088727 filed on July 6, 2021 and Korean Patent Application No. 10-2022-0081997 filed on July 4, 2022, and the contents disclosed in the specifications and drawings of said applications are incorporated herein in their entirety. [Background technology]

[0002] As technological development and demand for mobile devices increases, the demand for secondary batteries as energy sources is rapidly increasing. In particular, secondary batteries are attracting much attention as energy sources for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, as well as for power devices such as electric bicycles, electric cars, and hybrid electric cars.

[0003] Such secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet, according to the shape of the battery case. Here, the electrode assembly housed in the battery case is a power generating element that includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode and is capable of charging and discharging, and is classified into a jelly roll type in which a separator is interposed between a long sheet-type positive electrode and a negative electrode coated with an active material and wound up, and a stack type in which a plurality of positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them.

[0004] Among these, pouch-type batteries, which have a structure in which a stacked or stacked / folded electrode assembly is housed in a pouch-type battery case made of an aluminum laminate sheet, are increasingly being used due to their low manufacturing cost, light weight, and ease of deformation.

[0005] FIG. 1 is a top view of a conventional battery cell, and FIG. 2 is a cross-sectional view taken along line a-a' of FIG.

[0006] 1 and 2, a conventional battery cell 10 includes a battery case 20 in which an electrode assembly 11 is housed in a housing 21 and the outer periphery is sealed by a sealing portion 25. The battery cell 10 also includes an electrode lead 30 that is electrically connected to an electrode tab 15 included in the electrode assembly 11 and protrudes to the outside of the battery case 20 through the sealing portion 25, and a lead film 40 is located between the upper and lower parts of the electrode lead 30 and the sealing portion 25.

[0007] However, in recent years, as the energy density of a battery cell increases, the amount of gas generated inside the battery cell also increases. In the case of a conventional battery cell 10, since no components capable of discharging gas generated inside the battery cell are included, there is a risk of a venting phenomenon occurring in which the battery case 20 bursts due to gas generation during long-term storage. Furthermore, a battery cell damaged by the venting phenomenon may allow moisture to penetrate into the inside, causing side reactions that lead to a decrease in battery performance and additional gas generation. Thus, there is an increasing need to develop a battery cell with improved ability to discharge gas generated inside the battery cell to the outside. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a battery cell having improved sealing strength and safety as well as an improved ability to discharge gas generated inside the battery cell to the outside, and a battery cell manufacturing apparatus for manufacturing the same.

[0009] The problems to be solved by the present invention are not limited to the problems described above, and problems not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. [Means for solving the problem]

[0010] According to one aspect of the present invention, a battery cell includes a battery case including a storage portion in which an electrode assembly is attached and a sealing portion formed by sealing an outer periphery of the storage portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing portion; and a lead film located at a portion corresponding to the sealing portion on at least one of an upper part and a lower part of the electrode lead, the lead film including a first step portion protruding in a direction opposite to the electrode lead side, the sealing portion including a second step portion covering an outer surface of the first step portion, and a gas exhaust guide portion inserted into the first step portion.

[0011] A first step of the first step portion and a second step of the second step portion may each have a size corresponding to a height of the gas discharge guide portion.

[0012] The first step and the second step may have the same size.

[0013] The gas discharge guide may be located on a center portion of the electrode lead in a width direction of the lead film.

[0014] The gas discharge guiding portion may extend along a protruding direction of the electrode lead, and an end of the gas discharge guiding portion adjacent to an outside of the battery case may be covered with the lead film.

[0015] An end of the gas discharge guiding part adjacent to an inner side of the battery case may be exposed to the inside of the battery case. A gas discharge path may be formed at an interface between the gas discharge guiding part and the lead film.

[0016] An adhesive strength between the gas discharge guide portion and the lead film may be smaller than at least one of an adhesive strength between the lead film and an electrode lead and an adhesive strength between the lead film and the sealing portion.

[0017] The gas discharge guide portion may be a film layer made of at least one of polyimide and polyethylene terephthalate.

[0018] The gas discharge guide portion may be a coating layer made of a liquid resin.

[0019] The gas exhaust guide may further include a getter material including at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca).

[0020] The second step portion may be formed to have a uniform thickness.

[0021] The gas discharge guide may be located on the electrode lead, and an adhesive layer may be formed between the gas discharge guide and the electrode lead.

[0022] An adhesive strength between the gas discharge guide portion and the lead film may be smaller than an adhesive strength between the adhesive layer and the gas discharge guide portion and an adhesive strength between the adhesive layer and the electrode lead.

[0023] The adhesive layer may consist of an adhesive tape or an adhesive binder.

[0024] The gas permeability of the lead film may be 20 to 60 barrers at 60°C.

[0025] The lead film may have a moisture permeation amount of 0.02 g to 0.2 g over 10 years at 25° C. and 50% RH.

[0026] The gas discharge guide portion may have a gas permeability of 40 barrer or more at 60°C.

[0027] According to another aspect of the present invention, a battery cell manufacturing apparatus manufactures the above-mentioned battery cell and includes a sealing tool that seals the sealing portion, the electrode lead and the lead film together, the sealing tool including a third step portion recessed in an opposite direction to the sealing portion, the third step portion covering an outer surface of the first step portion, and the second step portion being located between the third step portion and the outer surface of the first step portion.

[0028] A first step of the first step portion, a second step of the second step portion, and a third step of the third step portion may each have a size corresponding to a height of the gas discharge guide portion.

[0029] The first step, the second step, and the third step may have the same size as each other. Effect of the Invention

[0030] According to one embodiment of the present invention, by providing a battery cell in which step portions are formed in the lead film and the sealing portion, and a battery cell manufacturing apparatus for manufacturing the same, it is possible to improve sealing strength and safety as well as the ability to discharge gas generated inside the battery cell to the outside.

[0031] Specifically, according to one embodiment of the present invention, a gas exhaust path can be formed at the interface between the gas exhaust guide portion and the lead film, making the manufacturing process relatively easy and allowing gas within the battery cell to be effectively exhausted to the outside.

[0032] According to another embodiment of the present invention, even though a first step portion is formed on the lead film, a second step portion is also formed on the sealing portion at a position corresponding to the first step portion, thereby improving the sealing strength between the sealing portion and the lead film. Furthermore, due to the high sealing strength between the sealing portion and the lead film, the vent pressure when gas generated in the battery cell is discharged to the outside is also increased, thereby improving safety.

[0033] According to another embodiment of the present invention, the shape of the gas discharge guide portion can be adjusted to control the gas discharge performance of the gas discharge guide portion and the durability and airtightness of the lead film. Also, the shape of the gas discharge guide portion can be changed as necessary to simplify the manufacturing process and reduce costs.

[0034] According to yet another embodiment of the present invention, by setting the gas permeability and moisture penetration amount of the lead film within a predetermined range, it is more effective in preventing moisture penetration from the outside while discharging gas generated inside the battery cell.

[0035] According to yet another embodiment of the present invention, there is provided a battery cell manufacturing apparatus for manufacturing a battery cell in which a first step portion is formed on a lead film and a second step portion is also formed on a sealing portion at a position corresponding to the first step portion. With such a battery cell manufacturing apparatus, a battery cell can be manufactured without forming an excess sealing portion on the sealing portion, so that it is possible to prevent a decrease in sealing strength between the excess sealing portion and the lead film when the excess sealing portion is formed. By maintaining a high sealing strength between the sealing portion and the lead film, the vent pressure when gas generated in the battery cell is discharged to the outside is also increased, and a battery cell with improved safety can be manufactured.

[0036] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a top view of a conventional battery cell. [Diagram 2] 2 is a cross-sectional view taken along line a-a' in FIG. [Diagram 3] FIG. 2 is a top view of a battery cell according to one embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of the area surrounded by the two-dot chain line in FIG. [Diagram 5]5 is a cross-sectional view taken along the line BB' in FIG. 4. [Figure 6] FIG. 4 is a cross-sectional view taken along line AA' in FIG. [Figure 7] 11A to 11C are diagrams showing various shapes of the gas discharge guide portion; [Figure 8] 7 is an enlarged view of the area enclosed by the two-dot chain line in FIG. 6. [Figure 9] 9 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 8. FIG. [Figure 10] 5 is a cross-sectional view taken along line BB' of FIG. 4, showing a battery cell according to another embodiment of the present invention. [Figure 11] 11 is a cross-sectional view taken along line AA' in FIG. 3 of a battery cell having the cross section of FIG. 10. FIG. [Figure 12] 12 is an enlarged view of the area enclosed by the two-dot chain line in FIG. 11. [Figure 13] 13 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 12. FIG. [Figure 14] 13A and 13B are diagrams illustrating a battery cell manufacturing apparatus according to another embodiment of the present invention, and a battery cell manufactured thereby. [Figure 15] 1A and 1B are diagrams showing a battery cell manufacturing apparatus according to a comparative example, and a battery cell manufactured by the apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0039] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0040] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not limited by the drawings. In the drawings, thicknesses are enlarged to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0041] Furthermore, throughout the specification, when a part "comprises" a certain component, this does not exclude other components, unless otherwise specified, but means that it may further include other components.

[0042] Furthermore, throughout the specification, a "plan view" means a view of the subject part viewed from above, and a "cross-sectional view" means a view of a vertical cross-section of the subject part viewed from the side.

[0043] Hereinafter, a battery cell according to an embodiment of the present invention will be described. However, the description will be made based on one end of the battery cell, but the present invention is not limited thereto, and the same or similar description may be applied to the other end of the battery cell.

[0044] FIG. 3 is a top view of a battery cell according to one embodiment of the present invention, and FIG. 4 is an enlarged view of the area enclosed by the two-dot chain line in FIG.

[0045] 3 and 4, the battery cell 100 according to an embodiment of the present invention includes a battery case 200 including a storage section 210 to which an electrode assembly 110 is attached and a sealing section 250 formed by sealing the outer periphery of the storage section 210, an electrode lead 300 electrically connected to an electrode tab 115 included in the electrode assembly 110 and protruding to the outside of the battery case 200 through the sealing section 250, and a lead film 400 located at a portion corresponding to the sealing section 250 at at least one of the upper and lower parts of the electrode lead 300. For example, the battery cell 100 may be a substantially rectangular plate-shaped cell by having a long side in the X-axis direction and a short side in the Y-axis direction, and being formed shorter in the Z-axis direction than the length of the X-axis or Y-axis. The electrode lead 300 may be formed on the short side of the battery cell 100. Such a battery cell 100 is an efficient structure for increasing energy density by integrating in the Z-axis direction and stacking a plurality of battery cells 100 face-to-face.

[0046] The battery case 200 may be made of a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 may be made of a laminate sheet and may be composed of an outer resin layer forming the outermost shell, a barrier metal layer that prevents the passage of substances, and an inner resin layer for sealing.

[0047] The electrode assembly 110 may have a jelly roll type (wound type), a laminate type (stack type), or a composite type (lamination / folding type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0048] The electrode lead 300 is electrically connected to the electrode tab 115 included in the electrode assembly 110, and protrudes to the outside of the battery case 200 through the sealing part 250. In addition, the lead film 400 is located at a portion corresponding to the sealing part 250 on at least one of the upper and lower parts of the electrode lead 300. Thus, the lead film 400, together with the sealing part 250, can prevent a short circuit from occurring in the electrode lead 300 during heat fusion or press fusion, and can improve the sealing property between the sealing part 250 and the electrode lead 300.

[0049] 3 and 4, the lead film 400 may have a width wider than that of the electrode lead 300. Here, the width of the lead film 400 means the maximum distance between one end and the other end of the lead film 400 in a direction (Y-axis direction) perpendicular to the protruding direction of the electrode lead 300 (X-axis direction), and the width of the electrode lead 300 means the maximum distance between one end and the other end of the electrode lead 300 in a direction perpendicular to the protruding direction of the electrode lead 300.

[0050] The lead film 400 may have a length longer than the sealing portion 250 and shorter than the electrode lead 300 based on the protruding direction of the electrode lead 300. Here, the length of the lead film 400 means the maximum value of the distance between one end and the other end of the lead film 400 in the protruding direction of the electrode lead 300. The length of the sealing portion 250 means the maximum value of the distance between one end and the other end of the sealing portion 250 in the protruding direction of the electrode lead 300. The length of the electrode lead 300 means the maximum value of the distance between one end and the other end of the electrode lead 300 in the protruding direction of the electrode lead 300. Thus, the lead film 400 does not interfere with the electrical connection of the electrode lead 300 and can prevent the side of the electrode lead 300 from being exposed to the outside.

[0051] FIG. 5 is a cross-sectional view taken along line BB' of FIG.

[0052] 4 and 5, the lead film 400 includes a first step portion 400p protruding in a direction opposite to the electrode lead 300 side, and a gas discharge guide portion 450 is inserted into the first step portion 400p.

[0053] Here, the first step portion 400p may refer to a portion protruding in the opposite direction to the electrode lead 300 side based on a surface where the lead film 400 and the sealing portion 250 contact each other. More specifically, the first step portion 400p may refer to a portion protruding in the opposite direction to the electrode lead 300 side at a position where the gas discharge guiding portion 450 is inserted. In other words, the first step portion 400p may refer to a portion where a step occurs between a portion of the lead film 400 where the gas discharge guiding portion 450 is inserted and a portion where the gas discharge guiding portion 450 is not inserted.

[0054] Also, the sealing portion 250 includes a second step portion 250p that covers the outer surface of the first step portion 400p. Here, the second step portion 250p may refer to a portion that protrudes along the protruding direction of the first step portion 400p based on a surface where the lead film 400 and the sealing portion 250 contact each other. More specifically, the second step portion 250p may refer to a portion that protrudes along the protruding direction of the first step portion 400p at a position where the first step portion 400p is formed. In other words, the second step portion 250p may refer to a portion where a step occurs between a portion of the sealing portion 250 where the first step portion 400p is formed and a portion where the first step portion 400p is not formed.

[0055] With the above configuration, in this embodiment, although the first step portion 400p is formed on the lead film 400, the sealing portion 250 also has the second step portion 250p formed at a position corresponding to the first step portion 400p, thereby improving the sealing strength between the sealing portion 250 and the lead film 400. Furthermore, due to the high sealing strength between the sealing portion 250 and the lead film 400, the vent pressure when gas generated within the battery cell 100 is discharged to the outside is also increased, thereby improving safety.

[0056] Also, in the lead film 400 and the sealing portion 250, the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p are not limited in size, but may have a size corresponding to the thickness D (height in the Z-axis direction) of the gas discharge guiding portion 450. More specifically, the first step d1 and the second step d2 may be the same as the thickness D of the gas discharge guiding portion 450, or may be larger or smaller than it. As an example, the first step d1 and the second step d2 may have the same size as the thickness D of the gas discharge guiding portion 450. As another example, the first step d1 and the second step d2 may have a size of 50% to 150% of the thickness D of the gas discharge guiding portion 450.

[0057] As described above, in this embodiment, the first step portion 400p on the lead film 400 and the second step portion 250p of the sealing portion 250 have a size corresponding to the thickness D of the gas exhaust guide portion 450, so that the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when gas generated within the battery cell 100 is exhausted to the outside are also increased, thereby improving safety.

[0058] More preferably, the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p may have the same size and may be the same as the thickness D of the gas discharge guide portion 450, respectively.

[0059] As a result, in this embodiment, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when gas generated within the battery cell 100 is discharged to the outside are also increased, thereby further improving safety.

[0060] On the other hand, if the second step d2 is larger or smaller than the first step d1, an unsealed portion or an over-sealed portion may occur between the lead film 400 and the sealing portion 250, which may reduce the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when gas generated within the battery cell 100 is discharged to the outside, thereby compromising safety.

[0061] Also, the second step portion 250p may be formed to have a uniform thickness in the sealing portion 250. More specifically, in the sealing portion 250, the second step portion 250p may cover and enclose the outer surface of the lead film 400 with the same thickness. In other words, in the sealing portion 250, the second step portion 250p may cover and enclose the outer surface of the first step portion 400p with the same thickness.

[0062] As described above, in this embodiment, even though the first step portion 400p is formed on the lead film 400, the sealing portion 250 can cover the outer surface of the lead film 400 with a uniform thickness, and the sealing strength between the sealing portion 250 and the lead film 400 and the thickness change rate before and after sealing of the sealing portion 250 are uniformly maintained. That is, the portion where the sealing strength is relatively weak between the sealing portion 250 and the lead film 400 can be minimized, and the vent pressure when gas generated in the battery cell 100 is discharged to the outside can be increased, thereby improving safety.

[0063] The thickness D of the gas discharge guiding portion 450 may be 50 μm to 150 μm. When the thickness of the gas discharge guiding portion 450 satisfies the above range, the gas inside the battery case 200 can be more easily discharged to the outside.

[0064] 4 and 5, the gas discharge guiding portion 450 may be located on the electrode lead 300. More specifically, the gas discharge guiding portion 450 may be located on the center of the electrode lead 300 based on the width direction of the lead film 400. In other words, the first step portion 400p and the second step portion 250p may be located on the center of the electrode lead 300 based on the width direction of the lead film 400, and the gas discharge guiding portion 450 may be inserted into the first step portion 400p.

[0065] In this manner, since the gas discharge guide portion 450 in the lead film 400 is positioned on the electrode lead 300, the gas discharge guide portion 450 has a relatively large area, and the amount of gas discharged by the gas discharge guide portion 450 can be effectively increased.

[0066] FIG. 6 is a cross-sectional view taken along line AA' of FIG.

[0067] 4 and 6, the gas discharge guiding portion 450 may extend along the protruding direction of the electrode lead 300. More specifically, in the gas discharge guiding portion 450, an end portion of the gas discharge guiding portion 450 adjacent to the outside of the battery case 200 may be covered with the lead film 400. In other words, the end portion of the gas discharge guiding portion 450 adjacent to the outside of the battery case 200 is not exposed to the outside of the battery case 200.

[0068] In addition, the end of the gas discharge guiding portion 450 adjacent to the inside of the battery case 200 may be exposed to the inside of the battery case 200. In other words, the end of the gas discharge guiding portion 450 adjacent to the inside of the battery case 200 may be located on the same vertical line as the end of the lead film 400, or may be located more inward of the battery case 200 than the end of the lead film 400.

[0069] In this manner, in the lead film 400, the end of the gas discharge guiding portion 450 adjacent to the outside of the battery case 200 is not exposed to the outside of the battery case 200, and the sealing force of the battery case 200 by the lead film 400 and the sealing portion 250 can be improved. Furthermore, in the lead film 400, the end of the gas discharge guiding portion 450 adjacent to the inside of the battery case 200 is exposed to the inside of the battery case 200, and gas generated in the battery cell 100 easily flows into the gas discharge path formed by the gas discharge guiding portion 450 and is effectively discharged to the outside.

[0070] 6, the thickness H (height in the Z-axis direction) of the lead film 400 on the upper surface of the gas discharge guide 450 may be 100 μm to 300 μm or 100 μm to 200 μm. When the thickness H of the lead film 400 satisfies the above-mentioned range, gas inside the battery case 200 is more easily discharged to the outside.

[0071] 6, the width W of the lead film 400 covering the front surface of the gas discharge guide portion 450 based on the protruding direction of the electrode lead 300 may be 2 mm or more, or 2 mm to 3 mm. When the width W of the lead film 400 satisfies the above-mentioned range, the lead film 400 can be prevented from being broken in the process of gas generated inside the battery case 200 being discharged to the outside.

[0072] 7 shows various shapes of the gas discharge guide portion 450. The gas discharge guide portion 450 may be formed in a predetermined pattern to discharge the gas inside the battery case 200.

[0073] As an example, the gas discharge guide portion 450 may have a rectangular shape extending along the protruding direction of the electrode lead 300 as shown in Fig. 4. However, without being limited thereto, the gas discharge guide portion 450 may have various shapes such as a circular shape as shown in Fig. 7(a), an elliptical shape as shown in Fig. 7(b), a linear shape, a curved shape, etc.

[0074] As another example, the gas discharge inducing part 450 may include a first gas discharge inducing part 450a extending along the protruding direction of the electrode lead 300 as shown in FIG. 7C, and a second gas discharge inducing part 450b extending in a direction perpendicular to the protruding direction of the electrode lead 300. In particular, the first gas discharge inducing part 450a and the second gas discharge inducing part 450b may be connected to each other. Here, the second gas discharge inducing part 450b may be located outside the sealing part 250 and inside the lead film 400 with respect to the sealing part 250 as shown in FIG. 7C, or may be located inside the sealing part 250 and outside the lead film 400 with respect to the sealing part 250 as shown in FIG. 7D. Alternatively, the second gas discharge inducing part 450b may be located both outside and inside the lead film 400 with respect to the sealing part 250 as shown in FIG. 7E. However, the gas exhaust guide portion 450 is not limited to the above shape, and may be inserted into the lead film 400 in any suitable shape.

[0075] In this manner, by adjusting the shape of the gas exhaust guiding portion 450 inserted in the lead film 400, it is possible to control the gas exhaust performance of the gas exhaust guiding portion 450 as well as the durability and airtightness of the lead film 400. In addition, by changing the shape of the gas exhaust guiding portion 450 as necessary, it is possible to simplify the manufacturing process and reduce costs.

[0076] 4, one gas discharge guide portion 450 may be included in the lead film 400. As another example, a plurality of gas discharge guide portions 450 may be inserted into the lead film 400 and positioned spaced apart from each other.

[0077] In this manner, by adjusting the number of gas exhaust guiding parts 450 inserted in the lead film 400, it is possible to control the gas exhaust performance of the gas exhaust guiding parts 450 and the durability and airtightness of the lead film 400. In addition, it is possible to simplify the manufacturing process and reduce costs by minimizing the number of gas exhaust guiding parts 450 as necessary.

[0078] Fig. 8 is an enlarged view of the area enclosed by the two-dot chain line in Fig. 6, and Fig. 9 is a view showing the gas discharge path formed at the interface between the lead film and the gas discharge guide part in Fig. 8. In Fig. 9, the gas movement path is indicated by the dotted arrow.

[0079] 8 and 9, in this embodiment, a gas exhaust path may be formed at the interface between the gas exhaust guiding part 450 and the lead film 400. More specifically, as shown in Fig. 9, the gas exhaust path may refer to a space that is separated from at least a portion of the interface between the gas exhaust guiding part 450 and the lead film 400 due to the pressure of gas generated in the battery case 200. That is, as shown in the direction of the dotted arrow in Fig. 9, the gas exhaust path may refer to a path through which gas flows into a space separated from the interface between the gas exhaust guiding part 450 and the lead film 400 and is exhausted to the outside.

[0080] Here, the adhesive strength between the gas discharge inducing unit 450 and the lead film 400 may be smaller than the adhesive strength between the lead film 400 and the electrode lead 300 and / or the adhesive strength between the lead film 400 and the sealing unit 250. More specifically, when the pressure inside the battery case 200 increases due to gas generated in the battery cell 100, the adhesive strength at the interface between the gas discharge inducing unit 450 and the lead film 400 is relatively smaller than the adhesive strength between the lead film 400 and other components, so that at least a portion of the interface between the gas discharge inducing unit 450 and the lead film 400 may be separated from each other due to the pressure of the gas generated in the battery cell 100, as shown in FIG.

[0081] That is, in this embodiment, due to the relatively low adhesive strength between the gas discharge guide portion 450 and the lead film 400, the gas discharge guide portion 450 and the lead film 400 are peeled off from each other, and the gas inside the battery cell 100 flows into the gas discharge passage formed at the interface between the gas discharge guide portion 450 and the lead film 400, and the gas moves along the gas discharge passage and is finally discharged through the lead film 400. The gas that has flowed into the gas discharge passage can be discharged to the outside due to the pressure difference with the outside.

[0082] However, the gas exhaust path may include not only the case where the interface between the upper surface of the gas exhaust guiding portion 450 and the lead film 400 and the interface between the lower surface of the gas exhaust guiding portion 450 and the lead film 400 are both separated as shown in FIG. 9, but also the case where the interface between the upper surface of the gas exhaust guiding portion 450 and the lead film 400 or the interface between the lower surface of the gas exhaust guiding portion 450 and the lead film 400 are separated.

[0083] As an example, the gas exhaust guiding unit 450 may be a film layer made of at least one of polyimide (PI) and polyethylene terephthalate (PET). As another example, the gas exhaust guiding unit 450 may be a coating layer made of liquid resin. However, the shape or material of the gas exhaust guiding unit 450 is not limited thereto, and any shape or material that provides a relatively lower adhesive strength at the interface between the gas exhaust guiding unit 450 and the lead film 400 than the adhesive strength between the lead film 400 and other components may be included in this embodiment.

[0084] As described above, in the battery cell according to this embodiment, a gas exhaust path can be formed at the interface between the gas exhaust guiding portion 450 and the lead film 400 due to the relatively low adhesive strength between the gas exhaust guiding portion 450 and the lead film 400, which not only makes the manufacturing process relatively easy but also enables the gas within the battery cell 100 to be effectively exhausted to the outside.

[0085] 4 and 6, one end of the gas discharge guiding part 450 may be located more inward than the inner surface of the sealing part 250 based on the protruding direction of the electrode lead 300. In this specification, the inner surface of the sealing part 250 means an end of the sealing part 250 adjacent to the inside of the battery case 200, and being located more inward than the inner surface of the sealing part 250 means being located more inward than the inner surface of the sealing part 250. When one end of the gas discharge guiding part 450 is located more inward than the inner surface of the sealing part 250, gas can easily flow into the gas discharge guiding part 450 without being interfered with by the sealing part 250.

[0086] In addition, the other end of the gas discharge guiding part 450 may be located outside the outer surface of the sealing part 250 based on the protruding direction of the electrode lead 300. In this specification, the outer surface of the sealing part 250 means the end of the sealing part 250 adjacent to the outside of the battery case 200, and located outside the outer surface of the sealing part 250 means located outside the battery case 200 than the outer surface of the sealing part 250. For example, a gap P is provided between the outer surface of the sealing part 250 and the other end of the gas discharge guiding part 450. In this way, when the other end of the gas discharge guiding part 450 is located outside the outer surface of the sealing part 250, the gas that has flowed into the gas discharge guiding part 450 can be more easily discharged to the outside. For example, the other end of the gas discharge guiding part 450 is not interfered with by the sealing part 250, and the gas that has flowed into the gas discharge guiding part 450 can be more easily discharged to the outside.

[0087] As a result, gas generated inside the battery cell 100 flows toward the gas discharge guiding portion 450, and the gas that has flowed into the gas discharge guiding portion 450 is smoothly discharged to the outside as shown in Fig. 9. In addition, the amount of gas generated inside the battery cell 100 that is discharged to the outside also increases. In this way, gas generated inside the battery case 200 can more easily flow into the gas discharge guiding portion 450, and can be more easily discharged to the outside of the gas discharge guiding portion 450.

[0088] 9, the gas flowing into the gas discharge guiding portion 450 can be more easily discharged in the Z-axis direction through the lead film 400 on the gas discharge guiding portion 450. For example, when the other end of the gas discharge guiding portion 450 is located outside the outer surface of the sealing portion 250, the gas flowing into the gas discharge guiding portion 450 can be discharged in the Z-axis direction from the lead film 400 portion between the other end of the gas discharge guiding portion 450 and the outer surface of the sealing portion 250. As described above, the thickness H of the lead film 400 on the upper surface of the gas discharge guiding portion 450 can be 100 μm to 300 μm, and the width W of the lead film 400 covering the front surface of the gas discharge guiding portion 450 based on the protruding direction of the electrode lead 300 can be 2 mm or more or 2 mm to 3 mm. When the other end of the gas discharge guiding portion 450 is located outside the outer surface of the sealing portion 250 as described above, the gas is discharged along the Z-axis direction, which is a relatively thin portion of the lead film 400, so that the gas can be more easily discharged. Furthermore, when discharging gas, if the gas discharge path is entirely covered by the sealing part 250, the gas discharge will not be smooth. Therefore, by providing a gap P between the outer surface of the sealing part 250 and the other end of the gas discharge guide part 450 as described above, it is possible to facilitate the gas discharge.

[0089] Also, the gas exhaust guiding unit 450 may further include a material having a function of absorbing or adsorbing moisture flowing in from the outside or hydrofluoric acid generated inside. More specifically, the gas exhaust guiding unit 450 may further include a getter material. Here, the getter material may mean a material that can be exhausted by using the action of gas being adsorbed by a chemically activated metal film. As an example, the getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca). As another example, the getter material may have a metal organic framework (MOF) structure. However, the getter material is not limited thereto and may include all types of materials generally classified as getter materials.

[0090] As described above, in the present embodiment, the gas exhaust guiding unit 450 further includes a material capable of absorbing or adsorbing moisture or hydrofluoric acid, so that the gas exhaust guiding unit 450 can further minimize the penetration of moisture or hydrofluoric acid flowing from the outside of the battery cell 100 into the inside of the battery cell 100. In one embodiment of the present invention, the gas permeability of the gas exhaust guiding unit 450 may be 40 barrers or more at 60° C. For example, the carbon dioxide permeability of the gas exhaust guiding unit 450 may satisfy the above-mentioned range.

[0091] For example, the gas discharge guide 450 may include at least one of polyolefin-based, fluorine-based, and porous ceramic-based materials that satisfy the above-mentioned gas permeability range. The polyolefin-based material may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinyldifluoride (PVDF). The fluorine-based material may include one or more materials selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride.

[0092] In one embodiment of the present invention, the gas permeability of the lead film 400 may be 20 to 60 Barrer, or 30 to 40 Barrer at 60° C. For example, the carbon dioxide permeability of the lead film 400 may satisfy the above-mentioned range. In addition, the gas permeability may satisfy the above-mentioned range at 60° C., based on the thickness H of the lead film 400 being 200 μm. When the gas permeability of the lead film 400 satisfies the above-mentioned range, gas generated inside the battery cell can be more effectively discharged.

[0093] As used herein, gas permeability may be measured by ASTM F2476-20.

[0094] In an embodiment of the present invention, the moisture permeation amount of the lead film 400 may be 0.02g to 0.2g, or 0.02g to 0.04g, or 0.06g, or 0.15g, over 10 years at 25° C. and 50% RH. When the moisture permeation amount of the lead film 400 satisfies the above range, the permeation of moisture entering from the lead film 400 can be more effectively prevented.

[0095] In one embodiment of the present invention, the lead film 400 may have a gas permeability of 20 to 60 Barrers at 60° C. and a moisture permeation amount of 0.02 g to 0.2 g over 10 years at 25° C. and 50% RH. When the gas permeability and moisture permeation amount of the lead film 400 satisfy the above-mentioned ranges, it is possible to more effectively prevent moisture permeation from the outside while discharging gas generated inside the battery cell 100.

[0096] The amount of moisture permeation of the lead film 400 may be measured according to ASTM F 1249. At this time, the measurement may be performed using an officially certified device from MCOON.

[0097] In one embodiment of the present invention, the lead film 400 may be made of an adhesive composition including at least one of a polyolefin-based material, an epoxy, and polyvinyl chloride (PVC). The polyolefin-based material may be polyethylene (PE), polypropylene (PP), etc. For example, the lead film 400 may include polyethylene, polypropylene, etc. that meets the above-mentioned gas permeability and / or moisture penetration values.

[0098] Furthermore, by making the lead film 400 from the above-mentioned material, the airtightness of the battery cell 100 can be maintained and leakage of the internal electrolyte can be prevented.

[0099] Hereinafter, a battery cell according to another embodiment of the present invention will be described. However, since most of the description of the battery cell 100 described above can be applied to the battery cell according to this embodiment, the description will be centered on the gas exhaust guide 450 inserted into the lead film 400 as a difference from the battery cell 100.

[0100] FIG. 10 is a cross-sectional view taken along line BB' of FIG. 4, showing a battery cell according to another embodiment of the present invention.

[0101] 10, in this embodiment, unlike FIG. 5, a gas exhaust guiding portion 450' may be located on the electrode lead 300'. More specifically, a separate lead film 400' is not located between the gas exhaust guiding portion 450' and the electrode lead 300'. That is, the gas exhaust guiding portion 450' may be inserted into the first step portion 400p' of the lead film 400' and may be located in contact with the electrode lead 300'. In other words, in this embodiment, the gas exhaust guiding portion 450' may be attached or fixed onto the electrode lead 300', and then the lead film 400' may cover the outer surface of the gas exhaust guiding portion 450'.

[0102] Since the gas exhaust guide portion 450' is positioned adjacent to the electrode lead 300', the thickness of the lead film 400' covering the gas exhaust guide portion 450' is relatively reduced, which has the advantage of reducing manufacturing costs and simplifying the manufacturing process.

[0103] Also, an adhesive layer 470' may be formed between the gas exhaust guiding portion 450' and the electrode lead 300'. Here, the adhesive layer 470' may extend along the interface between the gas exhaust guiding portion 450' and the electrode lead 300'. In this case, the adhesive layer 470' may be formed on the entire or part of the interface between the gas exhaust guiding portion 450' and the electrode lead 300'.

[0104] For example, the adhesive layer 470′ may be an adhesive tape or an adhesive binder, but is not limited thereto and may be any material having adhesive properties capable of fixing the gas exhaust guide unit 450′ and the electrode lead 300′ together.

[0105] As a result, the gas discharge guiding unit 450' is stably fixed to the electrode lead 300' by the adhesive layer 470'. That is, by forming the adhesive layer 470' having a relatively high adhesive strength between the gas discharge guiding unit 450' and the electrode lead 300', peeling due to an increase in the internal pressure of the battery cell 100 can be prevented, and the sealing strength of the battery cell 100 can be further improved.

[0106] Fig. 11 is a cross-sectional view taken along line A-A' in Fig. 3 of a battery cell having the cross-section of Fig. 10. Fig. 12 is an enlarged view of the area enclosed by the two-dot chain line in Fig. 11. Fig. 13 is a view showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in Fig. 12. In Fig. 13, the gas movement path is indicated by a dotted arrow.

[0107] 11 to 13, in this embodiment, a gas discharge path may be formed at the interface between a gas discharge guide portion 450' and a lead film 400', similar to Figures 6 to 9. However, in this embodiment, unlike Figures 6 to 9, the gas discharge guide portion 450' is located in contact with the electrode lead 300', and an adhesive layer 470' is formed between the gas discharge guide portion 450' and the electrode lead 300', so that a gas discharge path is not formed at the interface between the gas discharge guide portion 450' and the electrode lead 300'.

[0108] More specifically, in this embodiment, the adhesive strength between the gas discharge guide portion 450' and the lead film 400' is smaller than the adhesive strength between the adhesive layer 470' and the gas discharge guide portion 450' and / or the adhesive strength between the adhesive layer 470' and the electrode lead 300'.

[0109] More specifically, in this embodiment, when the pressure inside the battery cell 100 increases, the adhesive strength at the interface between the gas discharge guide portion 450' and the lead film 400' is relatively weaker than the adhesive strength between the lead film 400' and other components, so that at least a portion of the interface between the gas discharge guide portion 450' and the lead film 400' may be separated from each other due to the internal pressure of the battery cell 100, as shown in FIG. 13.

[0110] Furthermore, in this embodiment, the adhesive strength at the interface between the gas discharge guide portion 450' and the lead film 400' is smaller than the adhesive strength between the gas discharge guide portion 450' and the adhesive layer 470' and / or the adhesive strength between the adhesive layer 470' and the electrode lead 300', so that peeling off at the interface between the gas discharge guide portion 450' and the electrode lead 300' can be prevented when the internal pressure of the battery cell 100 increases.

[0111] That is, in this embodiment, only the interface between the gas exhaust guide 450' and the lead film 400' is peeled off to form a gas exhaust path, so that it is possible to increase the sealing strength of the battery cell 100 while maintaining the gas exhaust performance of the gas exhaust path. In addition, due to the high sealing strength, the vent pressure when gas generated within the battery cell 100 is exhausted to the outside is also increased, thereby improving safety.

[0112] Hereinafter, a battery cell manufacturing apparatus according to another embodiment of the present invention and a battery cell manufactured by the same will be described. This embodiment will be described based on the embodiment shown in Figures 3 to 9, but the same description can be given for the embodiment shown in Figures 10 to 13.

[0113] FIG. 14 is a diagram showing a battery cell manufacturing apparatus according to another embodiment of the present invention, and a battery cell manufactured by the apparatus.

[0114] 14, a battery cell manufacturing apparatus according to another embodiment of the present invention includes a sealing tool 1000 that manufactures a battery cell 100 and seals together the sealing portion 250, the electrode lead 300, and the lead film 400. Here, the sealing tool 1000 may seal the sealing portion 250, the electrode lead 300, and the lead film 400 by heat sealing or press sealing.

[0115] In addition, the sealing tool 1000 includes a third step portion 1000r recessed in the opposite direction to the sealing portion 250, and the third step portion 1000r covers the outer surface of the first step portion 400p, and the second step portion 250p may be located between the third step portion 1000r and the outer surface of the first step portion 400p. More specifically, the sealing tool 1000 may form the second step portion 250p between the first step portion 400p and the third step portion 1000r as shown in FIG. 14(b) by the third step portion 1000r pressing the sealing portion 250 with respect to the sealing portion 250 extending long as shown in FIG. 14(a).

[0116] Here, the third step portion 1000r may refer to a portion recessed in the opposite direction to the sealing portion 250 side based on a surface where the sealing tool 1000 and the sealing portion 250 contact each other. More specifically, the third step portion 1000r may refer to a portion recessed in the opposite direction to the sealing portion 250 side based on a position where the first step portion 400p is formed in the lead film 400. In other words, the third step portion 1000r in the sealing tool 1000 may refer to a portion where a step occurs between a portion where the first step portion 400p is formed and a portion where the first step portion 400p is not formed.

[0117] With the above configuration, in this embodiment, even though the first step portion 400p is formed on the lead film 400, the third step portion 1000r of the sealing tool 1000 can form the second step portion 250p at a position corresponding to the first step portion 400p, thereby improving the sealing strength between the sealing portion 250 and the lead film 400. Furthermore, due to the high sealing strength between the sealing portion 250 and the lead film 400, the vent pressure when gas generated within the battery cell 100 is discharged to the outside is also increased, thereby improving safety.

[0118] 5 and 14, in the sealing tool 1000, the third step d3 of the third step portion 1000r, together with the first step d1 and the second step d2, may have a size corresponding to the thickness D of the gas discharge guiding portion 450. More specifically, the size of the third step d3 may be the same as, larger than, or smaller than the gas discharge guiding portion 450. As an example, the first step d1 to the third step d3 may have the same size. As another example, the third step d3 may have a size of 50% to 150% of the thickness D of the gas discharge guiding portion 450.

[0119] In this manner, in the present embodiment, the third step portion 1000r of the sealing tool 1000 has a size corresponding to the thickness D of the gas discharge guiding portion 450, and thus may have the same size as the first step portion 400p, and the second step portion 250p of the sealing portion 250 may also have the same size as the first step portion 400p. That is, since the thickness of the second step portion 250p of the sealing portion 250 can be uniformly formed along the outer surface of the first step portion 400p, it is possible to uniformly maintain the sealing strength between the sealing portion 250 and the lead film 400 and the thickness change rate before and after sealing of the sealing portion 250. In addition, the sealing strength for the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside are also increased, and safety can be improved.

[0120] More preferably, the first step d1 to the third step d3 may have the same size and may be equal to the thickness D of the gas discharge guiding portion 450, respectively.

[0121] In this manner, in the present embodiment, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when gas generated within the battery cell 100 is discharged to the outside are also increased, thereby improving safety.

[0122] On the other hand, if the third step d3 is larger or smaller than the first step d1, the second step d2 of the sealing part 250 may not be formed with a uniform thickness. In particular, the sealing part 250 may be pressed with an excessively high pressure, resulting in a thin thickness, or the sealing part 250 may be pressed with an excessively low pressure, resulting in an unsealed area, which may reduce the sealing strength between the sealing part 250 and the lead film 400 and the vent pressure when gas generated in the battery cell 100 is discharged to the outside, thereby reducing safety. FIG 15 is a diagram showing a battery cell manufacturing apparatus according to a comparative example, and a battery cell manufactured thereby.

[0123] Referring to FIG. 15, the battery cell manufacturing apparatus according to the comparative example is the same as the battery cell manufacturing apparatus 1000 described above, except that the sealing tool 1001 does not include the third step portion 1000r.

[0124] Referring to FIG. 15, in a battery cell manufacturing apparatus according to the comparative example, if a third step portion 1000r is not formed in a position corresponding to the first step portion 400p in the sealing tool 1001, an excess sealing portion 250a may be formed in the sealing portion 250 as shown in (b) of FIG. 15.

[0125] 15(a), the sealing tool 1001 has a step having the same height at the entire position even though the first step portion 400p is formed on the lead film 400. At this time, the sealing tool 1001 applies a higher pressure to the sealing portion 250 facing the portion protruding due to the first step portion 400p. As a result, the sealing portion 250 may have a relatively thin excess sealing portion 250a formed in the portion facing the first step portion 400p as shown in FIG. 15(b).

[0126] As a result, the sealing tool 1001 having a step of the same height without considering the protruding height of the first step portion 400p formed on the lead film 400, as in the battery cell manufacturing apparatus according to the comparative example, forms an excess sealing portion 250a on the sealing portion 250, reducing the sealing strength between the excess sealing portion 250a and the lead film 400. Furthermore, the weak sealing strength between the excess sealing portion 250a and the lead film 400 reduces the vent pressure when gas generated in the battery cell is discharged to the outside, which may also reduce safety.

[0127] In contrast, in the case of the battery cell manufacturing apparatus according to this embodiment, the sealing tool 1000 includes a third step portion 1000r that takes into account the height protruding due to the first step portion 400p formed on the lead film 400, so that an excess sealing portion 250a as shown in (b) of Figure 15 is not formed on the sealing portion 250, and the sealing strength and safety between the sealing portion 250 and the lead film 400 can also be improved.

[0128] A battery module according to another embodiment of the present invention includes the above-mentioned battery cell. Meanwhile, one or more of the battery modules according to the present embodiment may be packaged in a pack case to form a battery pack.

[0129] The above-mentioned battery module and the battery pack including the same may be applied to various devices. Such devices may be means of transportation such as electric bicycles, electric cars, hybrid cars, etc. However, the present invention is not limited thereto, and the battery module and the battery pack including the same may be applied to various devices that can use the battery module, and these are also within the scope of the present invention.

[0130] Although a preferred embodiment of the present invention has been described in detail above, it goes without saying that the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention as claimed in the claims also fall within the scope of the present invention. [Explanation of symbols]

[0131] 100: Battery cell 110: Electrode assembly 200: Battery case 210: Storage section 250: Sealing part 300: Electrode lead 400: Lead film 450: Gas exhaust induction section 1000: Battery cell manufacturing equipment

Claims

1. a battery case including a receiving portion in which the electrode assembly is mounted and a sealing portion formed by sealing an outer periphery of the receiving portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing part; a lead film located at a portion corresponding to the sealing portion at at least one of an upper portion and a lower portion of the electrode lead, the lead film includes a first step portion protruding in a direction opposite to the electrode lead side, The sealing portion includes a second step portion that covers an outer surface of the first step portion, A gas exhaust guide portion is inserted into the first step portion, the gas discharge guiding portion extends along a protruding direction of the electrode lead, and an end of the gas discharge guiding portion adjacent to the outside of the battery case is covered and wrapped with the lead film.

2. The battery cell according to claim 1 , wherein the first step of the first step portion and the second step of the second step portion each have a size corresponding to a height of the gas discharge guide portion.

3. The battery cell according to claim 2 , wherein the first step and the second step have the same size.

4. The battery cell according to claim 1 , wherein the gas discharge guide portion is located on a center portion of the electrode lead with respect to a width direction of the lead film.

5. The battery cell according to claim 1 , wherein an end of the gas discharge guide portion adjacent to an inner side of the battery case is exposed to an inside of the battery case.

6. The battery cell according to claim 1 , wherein a gas discharge path is formed at an interface between the gas discharge guide portion and the lead film.

7. The battery cell of claim 6 , wherein an adhesive strength between the gas discharge guide portion and the lead film is smaller than at least one of an adhesive strength between the lead film and an electrode lead and an adhesive strength between the lead film and the sealing portion.

8. The battery cell according to claim 7 , wherein the gas discharge guide portion is a film layer made of at least one of polyimide and polyethylene terephthalate.

9. The battery cell according to claim 7 , wherein the gas discharge guide portion is a coating layer made of a liquid resin.

10. The gas exhaust guide portion is made of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO ２ 8. The battery cell of claim 7, further comprising a getter material comprising at least one of: barium oxide (BaO), barium (Ba), and calcium (Ca).

11. The battery cell according to claim 1 , wherein the second step portion has a uniform thickness.

12. The battery cell according to claim 1 , wherein the gas discharge guide portion is located on the electrode lead, and an adhesive layer is formed between the gas discharge guide portion and the electrode lead.

13. The battery cell of claim 12 , wherein an adhesive strength between the gas discharge guide portion and the lead film is smaller than at least one of an adhesive strength between the adhesive layer and the gas discharge guide portion and an adhesive strength between the adhesive layer and the electrode lead.

14. 14. The battery cell of claim 13, wherein the adhesive layer comprises an adhesive tape or an adhesive binder.

15. 2. The battery cell according to claim 1, wherein the gas permeability of the lead film is 20 to 60 barrers at 60°C.

16. 2. The battery cell according to claim 1, wherein the amount of moisture permeation into the lead film is 0.02 g to 0.2 g at 25° C. and 50% RH for 10 years.

17. The battery cell according to claim 1 , wherein the gas discharge guide portion has a gas permeability of 40 barrer or more at 60° C.

18. A battery cell manufacturing apparatus for manufacturing the battery cell according to claim 1, a sealing tool for sealing the sealing part, the electrode lead and the lead film together; The sealing tool includes a third step portion recessed in a direction opposite to the sealing portion, the third step portion covers and surrounds an outer surface of the first step portion, and the second step portion is located between the third step portion and the outer surface of the first step portion.

19. 20. The battery cell manufacturing apparatus of claim 18, wherein a first step of the first step portion, a second step of the second step portion, and a third step of the third step portion each have a size corresponding to a height of the gas discharge guiding portion.

20. The battery cell manufacturing apparatus of claim 19 , wherein the first step, the second step, and the third step have the same size.

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