Battery cell and battery module including same

Abstract

The application relates to a battery cell and a battery module including the same. A battery cell according to an embodiment of the present invention comprises: a battery case in which an electrode assembly is mounted in an accommodating portion, the battery case comprising a sealing portion having a structure for sealing an outer periphery thereof by hot melting; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing portion; and a lead film located at a portion corresponding to the sealing portion in at least one of an upper portion and a lower portion of the electrode lead, in which a recess is formed inside the lead film, and the recess extends through the sealing portion and is enclosed in the lead film.

Description

[0001] This application is a divisional application of the original invention patent application with application number 202280002856.5 (international application number: PCT / KR2022 / 000495, application date: January 11, 2022, invention name: battery cell and battery module including the battery cell).

[0002] This application claims priority to Korean Patent Application No. 10-2021-0003185 filed in Korea on January 11, 2021. Technical Field

[0003] The present disclosure relates to a battery cell and a battery module including the same, and more particularly, to a battery cell in which external discharge of gas generated inside the battery cell is improved and a battery module including the same. Background Art

[0004] With the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as energy sources is rapidly increasing. In particular, secondary batteries are receiving great attention as energy sources not only for mobile devices such as mobile phones, digital cameras, notebooks, and wearable devices, but also for power devices such as electric bicycles, electric vehicles, and hybrid vehicles.

[0005] According to the shape of the battery case, these secondary batteries are classified into cylindrical batteries and prismatic batteries in which the battery assembly is included in a cylindrical or prismatic metal can, and pouch batteries in which the battery assembly is included in a pouch case of an aluminum laminate. Here, the battery assembly included in the battery case is an electric element, which includes a positive electrode, a negative electrode, and a separator placed between the positive electrode and the negative electrode and is capable of charging and discharging, and is classified into a jelly roll type and a stacked type, in which a long sheet of positive and negative electrodes coated with an active material is wound with a separator placed between them, and in a stacked type. A plurality of positive and negative electrodes are stacked sequentially with a separator placed between them.

[0006] Among these secondary batteries, in particular, a stacked type or stacked / folded type battery assembly including a pouch-shaped battery in a pouch-shaped battery case made of an aluminum laminate sheet is increasingly being used due to low manufacturing cost, light weight, and easy refitting.

[0007] Figure 1 is a top view showing a conventional battery cell. Figure 2 is along Figure 1 A cross-sectional view taken along the axis aa′. Figure 1 and Figure 2The conventional battery cell 10 includes a battery case 20 having a receiving portion 21 in which a battery assembly 11 is mounted and a sealing portion 25 formed by sealing the periphery of the battery case 20 by thermal fusion. Here, the battery cell 10 includes an electrode lead 30 protruding out of the battery case 20 via the sealing portion 25, and a lead film 40 located between the upper and lower portions of the electrode lead 30 and the sealing portion 25.

[0008] However, as the energy density of battery cells has increased in recent years, there is a problem in that the amount of gas generated inside the battery cell has also increased. In the case of the conventional battery cell 10, a component capable of discharging the gas generated inside the battery cell is not included, so degassing may occur in the battery cell due to gas generation. In addition, moisture may penetrate into the battery cell damaged by degassing, which may cause side reactions, and there is a problem of battery performance degradation and generation of additional gas. Therefore, there is a growing need to develop a battery cell that improves the outward discharge of the gas generated inside the battery cell. Summary of the invention

[0009] Technical issues

[0010] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure aims to provide a battery cell and a battery module including the battery cell, which improve the external discharge of gas generated inside the battery cell.

[0011] The objects to be solved by the present disclosure are not limited to the above-mentioned objects, and objects not mentioned herein can be clearly understood by those skilled in the art from the present specification and the accompanying drawings.

[0012] Technical Solution

[0013] In one aspect of the present disclosure, a battery cell is provided, comprising: a battery case having a receiving portion and a sealing portion, wherein an electrode assembly is mounted in the receiving portion, the sealing portion being formed by sealing the periphery of the battery case by heat melting; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding out of the battery case via the sealing portion; and a lead film located at a portion corresponding to the sealing portion in at least one of an upper portion and a lower portion of the electrode lead, wherein a recess is formed inside the lead film, and the recess extends through the sealing portion and is enclosed inside the lead film.

[0014] The battery cell may further include an inner layer configured to cover at least one surface of an inner surface of the recessed portion of the lead film.

[0015] The material of the inner layer may have a higher melting point than the material of the lead film and may not react with the electrolyte.

[0016] The lead film may contain a polyolefin-based material.

[0017] The inner layer may contain at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material.

[0018] The length of the lead film may be greater than the width of the electrode lead.

[0019] The recess may be located above the electrode lead.

[0020] The recessed portion may be located between an end portion of the electrode lead and an end portion of the lead film.

[0021] Lead Film A width of the lead film may be greater than a width of the sealing portion and smaller than a length of the electrode lead.

[0022] Both ends of the recessed portion may be located between ends of the sealing portion and ends of the lead film, respectively.

[0023] The recess may have a rectangular shape.

[0024] The recess may include a pair of first recesses and a pair of second recesses connected to each other, the first recesses may extend in a protruding direction of the electrode lead, and the second recesses may extend in a length direction of the sealing portion.

[0025] The lead film may include a first lead film and a second lead film, the first lead film may be located at an upper portion of the electrode lead, and the second lead film may be located at a lower portion of the electrode lead.

[0026] The electrode lead may be located between the first lead film and the second lead film, and the first lead film and the second lead film may be connected to each other.

[0027] The recess may be located in at least one of the first lead film and the second lead film.

[0028] One end of the recessed portion may be located further outside than the outer surface of the battery case.

[0029] The other end of the recessed portion may be located further inside than the inner surface of the battery case.

[0030] An area of ​​the recess located outside the outer surface of the battery case may be the same as an area of ​​the recess located inside the inner surface of the battery case.

[0031] An area of ​​the recess located outside the outer surface of the battery case may be larger than an area of ​​the recess located inside the inner surface of the battery case.

[0032] The width of the front surface of the lead film surrounding the recess may be 2 mm or more based on the protruding direction of the electrode lead.

[0033] The thickness of the upper surface of the lead film surrounding the recess may be 100 μm to 300 μm.

[0034] The lead film may have a gas permeability of 20 to 60 Barrer at 60°C.

[0035] The lead film may have a moisture permeation amount of 0.02 g to 0.2 g in 10 years under the conditions of 25° C., 50% RH.

[0036] In another aspect of the present disclosure, a battery module is provided, which includes the above-mentioned battery unit.

[0037] Technical Effects

[0038] According to an embodiment, the present disclosure provides a battery cell having a recess inside a lead and a battery module including the battery cell, and thus it is possible to improve the outward discharge of gas generated inside the battery cell.

[0039] The effects of the present disclosure are not limited to the above effects, and effects not mentioned here will be clearly understood by those skilled in the art through this specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a top view showing a conventional battery cell.

[0041] Figure 2 is along Figure 1 A cross-sectional view taken along the axis aa′.

[0042] Figure 3 is a plan view showing a battery cell according to the present embodiment.

[0043] Figure 4 It shows that the Figure 3 A three-dimensional view of the electrode leads in a battery cell.

[0044] Figure 5 is along Figure 4 A cross-sectional view taken along the axis cc′.

[0045] Figure 6 is along Figure 4 A cross-sectional view taken along the axis dd′.

[0046] Figure 7 is along Figure 3 A cross-sectional view taken along the axis bb′.

[0047] Figure 8It is a diagram showing the flow of gas generated inside a battery cell and exhausted to the outside.

[0048] Fig. 9 It shows Figure 3 A magnified view of the electrode leads in a battery cell.

[0049] Fig.10 It shows that according to Fig. 9 FIG. 1 is a diagram of an electrode lead according to another embodiment of the present invention.

[0050] Fig.11 It shows that according to Fig. 9 (a) is an enlarged view of the electrode lead at the location of the sealing portion. DETAILED DESCRIPTION

[0051] Hereinafter, with reference to the accompanying drawings, various embodiments of the present disclosure will be described in detail so as to be easily implemented by those skilled in the art. The present disclosure can be implemented in various different forms and is not limited to the embodiments described herein.

[0052] In order to clearly explain the present disclosure, parts irrelevant to the description are omitted, and the same or similar components are given the same reference numerals throughout the specification.

[0053] In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for the convenience of description, the present disclosure is not necessarily limited to the drawings. In order to clearly indicate each layer and region in the drawings, the thickness is exaggerated. In addition, in the drawings, for the convenience of description, the thickness of some layers and regions is exaggerated.

[0054] In addition, throughout the specification, when a part “includes” a certain component, unless otherwise mentioned, it means that other components may be further included, rather than excluding other components.

[0055] In addition, throughout the specification, when a “top view” is mentioned, it means a target portion observed from above, and when a “cross-sectional view” is mentioned, it means a vertically cut cross section of the target portion observed from the side.

[0056] Hereinafter, the pouch-shaped battery cell 100 according to an embodiment of the present disclosure will be described. However, the description will be based on one of the two side surfaces of the pouch-shaped battery cell 100, but is not necessarily limited thereto, and the same or similar content may be described in the case of the other side surface.

[0057] Figure 3 is a plan view showing a battery cell according to the present embodiment.

[0058] Reference Figure 3, the battery cell 100 according to this embodiment includes a battery case 200 , an electrode lead 300 , and a lead film 400 .

[0059] The battery case 200 includes a receiving portion 210 in which the electrode assembly 110 is mounted, and a sealing portion 250 formed by hot-melt sealing the periphery of the battery case. The battery case 200 may be a laminate including a resin layer and a metal layer. More specifically, the battery case 200 may be made of a laminate, and may include an outer resin layer forming the outermost layer, a barrier metal layer to prevent material penetration, and an inner resin layer for sealing.

[0060] In addition, the electrode assembly 110 may have a jelly roll type (winding type), a stacked type (laminated type), or a composite type (stacked / folded type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0061] Hereinafter, the electrode lead 300 and the lead film 400 will be mainly described.

[0062] Figure 4 It shows that the Figure 3 A three-dimensional view of the electrode leads in a battery cell.

[0063] Reference Figure 3 and Figure 4 , the electrode lead 300 is electrically connected to an electrode tab (not shown) included in the electrode assembly 110, and protrudes out of the battery case 200 via the sealing portion 250. In addition, the lead film 400 is located at a portion corresponding to the sealing portion 250 in at least one of the upper and lower portions of the electrode lead 300. Therefore, the lead film 400 can improve the sealing properties of the sealing portion 250 and the electrode lead 300 while preventing a short circuit from occurring in the electrode lead 300 during heat fusion.

[0064] Figure 5 is along Figure 4 A cross-sectional view taken along the axis cc′. Figure 6 is along Figure 4 A cross-sectional view taken along the axis dd′.

[0065] Reference Figure 5 and Figure 6 In the lead film 400 , a recess 450 is formed inside the lead film 400 , and the recess 450 extends through the sealing portion 250 but is closed in the lead film 400 .

[0066] Therefore, in the lead film 400, the gas generated inside the battery case 200 can be discharged to the recess 450 due to the pressure difference with the inside of the recess 450, and the gas introduced into the recess 450 can be discharged toward the outside due to the pressure difference. In addition, since the recess 450 of the lead film 400 is closed, the recess 450 is not exposed to the electrolyte inside the battery case 200, and the airtightness and durability of the bag can be ensured.

[0067] By adjusting the area of ​​the recess 450 exposed in each of the inside and the outside of the battery case 200 , the amount of exhaust gas may be controlled.

[0068] Figure 7 is along Figure 3 A cross-sectional view taken along the axis bb′.

[0069] Reference Figure 7 One end of the recess 450 may be located further inside than the inner surface of the battery case 200 . In addition, the other end of the recess 450 may be located further outside than the outer surface of the battery case 200 .

[0070] Here, the inner surface of the battery case 200 refers to the end of the sealing portion 250 of the battery case 200 inside the battery. In addition, the outer surface of the battery case 200 refers to the end of the sealing portion 250 of the battery case 200 outside the battery.

[0071] Therefore, the lead film 400 can maximize the area of ​​the recess 450 and discharge a large amount of gas.

[0072] In one embodiment of the present disclosure, the area of ​​the recess 450 located outside the outer surface of the battery case 200 may be the same as the area of ​​the recess 450 located inside the inner surface of the battery case 200 .

[0073] In another embodiment of the present disclosure, the area of ​​the recess 450 located further outside than the outer surface of the battery case 200 may be greater than the area of ​​the recess 450 located further inside than the inner surface of the battery case 200. The exhaust volume is proportional to the product of the exhaust area and the pressure. Since the pressure inside the battery case 200 is greater than the pressure outside the battery case 200, if the area of ​​the recess 450 located further outside than the outer surface of the battery case 200 is greater than the area of ​​the recess 450 located further inside than the inner surface of the battery case 200, the gas generated inside the battery case 200 can be more easily discharged to the outside.

[0074] In one embodiment of the present disclosure, the area of ​​the recess 450 located outside the outer surface of the battery housing 200 may be 40 mm. 2 Up to 80mm 2This is based on the fact that at 60°C and 1 atmosphere internal pressure, approximately 0.5cc to 3cc of gas can be discharged per day. In addition, this is based on the fact that at 25°C and 50% RH, the amount of water infiltration can be 0.02g to 0.2g in 10 years.

[0075] Reference Figure 7 , the thickness H of the upper surface and / or lower surface of the lead film 400 surrounding the recess 450 may be 100 μm to 300 μm, or 100 μm to 200 μm. If the thickness H of the upper surface of the lead film 400 surrounding the recess 450 satisfies the above range, the gas inside the battery case 200 can be more easily discharged to the outside.

[0076] Reference Figure 7 , based on the protruding direction of the electrode lead 300, the width W of the front surface and / or rear surface of the lead film 400 surrounding the recess 450 may be 2 mm or more, or 2 mm to 3 mm. Here, the width of the front surface of the lead film 400 surrounding the recess 450 refers to the maximum value of the distance between the outer end of the battery case 200 at the recess 450 and the outer end of the battery case 200 at the lead film 400, and the width of the rear surface of the lead film 400 surrounding the recess 450 refers to the maximum value of the distance between the inner end of the battery case 200 at the recess 450 and the inner end of the battery case 200 at the lead film 400. If the width W of the front and / or rear surface of the lead film 400 surrounding the recess 450 satisfies the above range, it is possible to easily prevent the phenomenon that the lead film 400 is torn while the gas generated inside the battery case 200 is discharged to the outside.

[0077] Figure 8 It is a diagram showing the flow of gas generated inside a battery cell and exhausted to the outside.

[0078] Reference Figure 8 , the gas generated inside the battery cell 100 can be discharged toward the recess 450 of the lead film 400. Here, the internal pressure of the battery cell 100 is higher than the internal pressure of the recess 450, and the pressure difference generated thereby can serve as a driving force for the gas. In addition, due to the gas introduced from the inside of the battery cell 100, the inside of the recess 450 can have a pressure difference with the outside, so that the gas introduced into the recess 450 can be discharged to the outside.

[0079] Therefore, the gas generated inside the battery cell 100 can be discharged toward the recess 450, and the gas introduced into the recess 450 can be easily discharged toward the outside. In addition, the amount of gas generated inside the battery cell 100 and discharged to the outside can also be increased.

[0080] At this time, the gas generated inside the battery case 200 can be discharged in the Z-axis direction via the recess 450 and the lead film 400 surrounding the upper surface of the recess 450. For example, when the recess 450 is exposed to the outside of the battery case 200, the gas generated inside the battery case 200 can be discharged in the Z-axis direction via the recess 450 and the lead film 400 surrounding the upper surface of the recess.

[0081] In one embodiment of the present disclosure, the gas permeability of the lead film 400 may be 20 Barrer to 60 Barrer, or 30 Barrer to 40 Barrer at 60°C. For example, the carbon dioxide gas permeability of the lead film 400 may satisfy the above range. In addition, based on the thickness of the lead film 400 of 200 μm, the gas permeability may satisfy the above range at 60°C. If the gas permeability of the lead film 400 satisfies the above range, the gas generated inside the secondary battery can be more effectively discharged.

[0082] In this specification, the gas permeability may be measured by ASTM F2476-20.

[0083] In one embodiment of the present disclosure, under the conditions of 25° C. and 50% RH, the moisture permeation of the lead film 400 may be 0.02 g to 0.2 g, or 0.02 g to 0.04 g, or 0.06 g, or 0.15 g within 10 years. If the moisture permeation of the lead film 400 satisfies the above range, moisture can be more effectively prevented from penetrating from the lead film 400.

[0084] In one embodiment of the present disclosure, the lead film 400 has a gas permeability of 20 to 60 Barrer at 60°C and a water permeability of 0.02 to 0.2 g within 10 years at 25°C and 50% RH.

[0085] When the amount of permeation satisfies the above range, it is possible to more effectively prevent moisture from penetrating from the outside while discharging the gas generated inside the secondary battery.

[0086] The ASTM F 1249 method may be used to measure the moisture permeation amount of the lead film 400. At this time, the moisture permeation amount may be measured using equipment officially certified by MCOON.

[0087] In one embodiment of the present disclosure, the lead film 400 may include a polyolefin-based resin. For example, the lead film 400 may include a polyolefin-based resin that satisfies the above-mentioned gas permeability and / or moisture permeability values. The polyolefin-based resin may include at least one material selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). Although the lead film 400 contains polypropylene, the gas permeability of the lead film 400 may be 20 Barrer to 60 Barrer at 60°C. In addition, the moisture permeability may be 0.06g to 0.15g. In this case, the gas generated inside the secondary battery can be more effectively discharged, and moisture can be easily prevented from penetrating from the outside.

[0088] In addition, since the lead film 400 is made of the above-mentioned material, the lead film 400 can maintain the airtightness of the battery cell 100 and prevent the internal electrolyte from leaking.

[0089] In addition, refer to Figure 5 and 6 , the lead film 400 may further include an inner layer 410 covering at least one of the inner surfaces of the recess 450 .

[0090] For example, refer to Figure 5 (a) and Figure 6 (a), the inner layer 410 in the recess 450 may cover the entire surface of the lead film 400. That is, the inner layer 410 may be formed on the entire inner surface of the recess 450.

[0091] Therefore, even if the lead film 400 is heat-fused together with the sealing portion 250 in a state of being located in at least one of the upper and lower portions of the electrode lead 300 , the recess 450 may be retained in a non-heat-fused state by the inner layer 410 .

[0092] As another example, refer to Figure 5 (b) and Figure 6 (b), the inner layer 410 may cover the upper surface or the lower surface among the inner surfaces of the recess 450. That is, the recess 450 may have the inner layer 410 formed on at least one of the upper surface and the lower surface facing each other.

[0093] Therefore, while the lead film 400 minimizes the inner layer 410 formed in the recess 450, the recess 450 can be retained in a non-thermal melt state by the inner layer 410. In addition, the manufacturing process can be simplified and the cost can be reduced.

[0094] More specifically, the inner layer 410 may be made of a material having a higher melting point than the material constituting the lead film 400. In addition, the inner layer 410 may be made of a material that does not react with the electrolyte contained in the battery case 200. Therefore, since the inner layer 410 is made of the above-mentioned material, the inner layer 410 does not react with the electrolyte alone and does not cause thermal melting, thermal deformation, etc. in the high-temperature thermal melting process, so that the recess 450 can remain empty. In addition, the gas generated in the battery case 200 can be easily discharged to the outside.

[0095] In one embodiment of the present disclosure, the thickness of the inner layer 410 may be 100 μm or less.

[0096] In one embodiment of the present disclosure, the air permeability of the inner layer 410 may be greater than 40 Barrer. For example, the carbon dioxide permeability of the inner layer 410 may satisfy the above range.

[0097] For example, inner layer 410 may include at least one of polyolefin-based materials, fluorine-based materials and porous ceramic-based materials. For example, inner layer 410 may include at least one of polyolefin-based materials, fluorine-based materials and porous ceramic-based materials that meet the above gas permeability values. Polyolefin-based materials may include at least one material selected from the group consisting of polypropylene, polyethylene and polyvinylidene fluoride (PVDF). Fluorine-based materials may include at least one material selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride. In addition, inner layer 410 may include a getter material so that gas permeability can be increased while water permeability can be minimized. As an example, the getter material may be calcium oxide (CaO), barium oxide (BaO), lithium chloride (LiCl), silicon dioxide (SiO2), etc., and any material that reacts with water (H2O) may be used without being limited thereto.

[0098] The inner layer 410 may have an adhesive material between the lead film 400 and the inner layer 410, or may be stretched together with the lead film 400 and bonded to the lead film 400. The adhesive material may include an acrylic-based material. In particular, when the inner layer 410 is stretched together with the lead film 400, the gas permeability of the inner layer 410 may be 40 Barrer or more.

[0099] Fig. 9 It shows Figure 3 An enlarged view of the electrode leads in a battery cell. Fig.10 It shows Fig. 9 FIG. 1 is a diagram of an electrode lead according to another embodiment of the present invention. Fig.11 It shows that according to Fig. 9 (a) is an enlarged view of the electrode lead at the location of the sealing portion.

[0100] Reference Fig. 9 and Fig.10 , in the lead film 400 , the recess 450 may be formed at various positions with respect to the electrode lead 300 .

[0101] For example, Fig. 9 (a) and Fig.10 As shown in (a) of FIG. 4 , in the lead film 400 , the recess 450 may be located above the electrode lead 300 . More specifically, the recess 450 may be formed at a position corresponding to the center of the electrode lead 300 .

[0102] As another example, Fig. 9 (b) and Fig.10 As shown in (b), the length of the lead film 400 may be greater than the width of the electrode lead 300, and the recess 450 may be located between the end of the electrode lead 300 and the end of the lead film 400. Here, the length of the lead film 400 refers to the maximum value of the distance between one end and the other end of the lead film 400 in a direction orthogonal to the protruding direction of the electrode lead 300, and the width of the electrode lead 300 refers to the maximum value of the distance between one end and the other end of the electrode lead 300 in a direction orthogonal to the protruding direction of the electrode lead 300. In other words, in the lead film 400, the recess 450 may be formed at a position avoiding the electrode lead 300. However, the position of the recess 450 is not limited to the above, and the recess 450 may be formed at an appropriate position within the lead film 400.

[0103] Therefore, by adjusting the position of the recess 450 formed in the lead film 400, the durability and airtightness of the lead film 400 can be controlled. In addition, if necessary, by adjusting the size of the recess 450 according to the position of the recess 450, the manufacturing process can be simplified and the cost can be reduced.

[0104] Reference Fig. 9 and Fig.10 , in the lead film 400 , the recess 450 may be formed in various shapes.

[0105] For example, Fig. 9 As shown, the recess 450 may include a pair of first recesses and a pair of second recesses connected to each other, wherein the first recess may extend along the protruding direction of the electrode lead 300 and the second recess may extend along the length direction of the sealing portion 250. Here, the length direction of the sealing portion 250 refers to a direction perpendicular to the protruding direction of the electrode lead 300.

[0106] As another example, the recess 450 may have a Fig.10The rectangular shape shown. Here, the width of the lead film 400 may be greater than the width of the sealing portion 250 and may be less than the length of the electrode lead 300. Here, the width of the lead film 400 refers to the maximum value of the distance between one end and the other end of the lead film in the protruding direction of the electrode lead 300. The width of the sealing portion 250 refers to 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 refers to 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. At this time, the two ends of the recess 450 may be located between the ends of the sealing portion 250 and the ends of the lead film 400, respectively. However, the shape of the recess 450 is not limited to the above, and the recess 450 can be formed in a suitable shape within the lead film 400.

[0107] Therefore, by adjusting the shape of the recess 450 formed in the lead film 400, the durability and airtightness of the lead film 400 can be controlled. In addition, by changing the shape of the recess 450 as needed, the manufacturing process can be simplified and the cost can be reduced.

[0108] Reference Fig.11 In the lead film 400, one surface of the recess 450 adjacent to the outside may be formed adjacent to the end of the lead film 400. Fig.11 (a) and Fig.11 Compared with (b), even if the position of the sealing portion 250 in contact with the lead film 400 is changed, it can be found that there is no influence on one surface of the recess 450 adjacent to the outside. Fig.11 Involving Fig. 9 The shape of the recess 450, but the same description can be applied to Fig.10 situation.

[0109] Therefore, in the present embodiment, within the error range according to the positions of the lead film 400 and the sealing portion 250 generated in the hot melt process, one surface of the recess 450 adjacent to the outside can uniformly maintain an area located outside based on the battery case 200, and can also uniformly maintain an area in which the gas introduced into the recess 450 in the battery case 200 can be discharged to the outside. Therefore, there is an advantage that the exhaust effect of the recess 450 can also be maintained.

[0110] Reference Figures 4 to 6 , the lead film 400 may include a first lead film and a second lead film, the first lead film may be located at an upper portion of the electrode lead 300, and the second lead film may be located at a lower portion of the electrode lead 300. At this time, the electrode lead 300 may be thermally melted together with the sealing portion 250 in a state of being located between the first lead film and the second lead film, so that the first lead film and the second lead film may be connected to each other.

[0111] Therefore, the lead film 400 may prevent the side surface of the electrode lead 300 from being exposed to the outside while improving the sealing property of the sealing portion 250 and the electrode lead 300 .

[0112] For example, in the lead film 400, the recess 450 may be located in at least one of the first lead film and the second lead film. More specifically, in the lead film 400, the recess 450 may be formed in the first lead film or the second lead film based on the electrode lead 300, or the recess 450 may be formed on both the first lead film and the second lead film based on the electrode lead 300. However, the number of the recesses 450 is not limited to the above, and the lead film 400 may be formed in an appropriate number.

[0113] Therefore, by adjusting the number of recesses 450 formed in the lead film 400, the durability and airtightness of the lead film 400 can be controlled. In addition, by minimizing the number of recesses 450 as needed, the manufacturing process can be simplified and the cost can be reduced.

[0114] As an example, the concave portion 450 is connected to the battery cell 100 by the gas inside the battery cell 100. Figure 7 However, in the present embodiment, since the recess 450 is closed from the inside and outside of the battery case, the expansion degree can be relatively small, and thus the deformation of the component can also be correspondingly small.

[0115] A battery module according to another embodiment of the present disclosure includes the above-mentioned battery cell. Meanwhile, one or more battery modules according to this embodiment may be packaged in a battery pack case to form a battery pack.

[0116] The battery module and the battery pack including the battery module can be applied to various devices. These devices can be vehicles such as electric bicycles, electric vehicles, hybrid electric vehicles, etc., but the present disclosure is not limited thereto, and the present disclosure can be applied to various devices that can use the battery module and the battery pack including the battery module, which is also within the scope of the present disclosure.

[0117] Although the preferred embodiments of the present disclosure have been described in detail above, the scope of rights of the present disclosure is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present disclosure defined in the appended claims also fall within the scope of rights of the present disclosure.

Claims

1. A battery cell, comprising: a battery case having a housing portion in which the electrode assembly is mounted and a sealing portion formed by sealing the outer periphery of the battery case by thermal fusion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding out of the battery case via the sealing portion; as well as a lead film located at a portion corresponding to the sealing portion in at least one of an upper portion and a lower portion of the electrode lead, wherein a recess is formed inside the lead film, The recess extends through the sealing portion and is enclosed inside the lead film, and The gas generated inside the battery case is discharged through the recess and the lead film.

2. The battery cell according to claim 1, wherein: The lead film further comprises: An inner layer is configured to cover at least one surface of an inner surface of the recessed portion of the lead film.

3. The battery cell according to claim 2, in, The material of the inner layer has a higher melting point than the material of the lead film and does not react with the electrolyte.

4. The battery cell according to claim 1, in, The lead film contains a polyolefin-based material.

5. The battery cell according to claim 3, in, The inner layer contains at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material.

6. The battery cell according to claim 1, in, The length of the lead film is greater than the width of the electrode lead.

7. The battery cell according to claim 1, in, The recess is located above the electrode lead.

8. The battery cell according to claim 6, in, The recessed portion is located between an end portion of the electrode lead and an end portion of the lead film.

9. The battery cell according to claim 1, in, The width of the lead film is greater than the width of the sealing portion and smaller than the length of the electrode lead.

10. The battery cell according to claim 9, in, Both ends of the recessed portion are located between ends of the sealing portion and ends of the lead film, respectively.

11. The battery cell according to claim 10, in, The recess has a rectangular shape.

12. The battery cell according to claim 10, in, The recessed portion includes a pair of first recessed portions and a pair of second recessed portions connected to each other, The first recess extends along a protruding direction of the electrode lead, and The second recess extends along a length direction of the sealing portion.

13. The battery cell according to claim 10, wherein: In the lead film, one surface of the recessed portion adjacent to the outside is formed adjacent to an end portion of the lead film.

14. The battery cell according to claim 1, in, The lead film includes a first lead film and a second lead film, The first lead film is located on the upper portion of the electrode lead, and The second lead film is located at the lower part of the electrode lead.

15. The battery cell according to claim 14, in, The electrode lead is located between the first lead film and the second lead film, and the first lead film and the second lead film are connected to each other.

16. The battery cell according to claim 15, in, The recessed portion is located in at least one of the first lead film and the second lead film.

17. The battery cell according to claim 1, in, One end of the recessed portion is located outside the outer surface of the battery case.

18. The battery cell according to claim 17, in, The other end of the recessed portion is located further inside than the inner surface of the battery case.

19. The battery cell according to claim 17, in, An area of ​​the recessed portion located outside the outer surface of the battery case is equal to an area of ​​the recessed portion located inside the inner surface of the battery case.

20. The battery cell according to claim 17, in, An area of ​​the recessed portion located outside the outer surface of the battery case is larger than an area of ​​the recessed portion located inside the inner surface of the battery case.

21. The battery cell according to claim 1, in, The width of the front surface of the lead film surrounding the recessed portion is 2 mm or more based on the protruding direction of the electrode lead.

22. The battery cell according to claim 1, in, The thickness of the upper surface of the lead film surrounding the recessed portion is 100 μm to 300 μm.

23. The battery cell according to claim 1, in, The lead film has a gas permeability of 20 to 60 Barrer at 60°C.

24. The battery cell according to claim 1, in, The lead film has a moisture permeation amount of 0.02 g to 0.2 g within 10 years under the conditions of 25° C. and 50% RH. 25 . A battery module comprising the battery cell according to claim 1 .

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