Battery cell and battery module comprising the same

Abstract

A battery cell according to an embodiment of the present application includes a battery case having a storage portion in which an electrode assembly is mounted and including a sealing portion having a structure of a sealed outer circumferential side, and a gas discharge portion inserted into the sealing portion and fused together with the sealing portion, wherein the gas discharge portion includes a first layer and a second layer and has a folding structure with reference to a first boundary line, the gas discharge portion is open toward an inside of the battery case, and the first layer serves as an outer surface of the gas discharge portion such that the first layer and the sealing portion are in contact with each other.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2021-0053775, filed in Korea on April 26, 2021.

[0002] This disclosure relates to a battery cell and a battery module including the battery cell, and more specifically, to a battery cell and a battery module including the battery cell that can suppress moisture penetration into the battery cell while improving the external emission of gases generated inside the battery cell. Background Technology

[0003] With technological advancements and increasing demand for mobile devices, the need for secondary batteries as an energy source is rapidly growing. In particular, secondary batteries are attracting attention not only as a power source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also as a power source for power equipment such as electric bicycles, electric vehicles, and hybrid vehicles.

[0004] Based on the shape of the battery casing, these secondary batteries are classified into cylindrical and prismatic batteries in which the battery assembly is contained in a cylindrical or prismatic metal can, and pouch batteries in which the battery assembly is contained in a pouch-shaped casing of aluminum laminate. Here, the battery assembly contained in the battery casing is a power element that includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes and is capable of charging and discharging. It is classified into wound type and stacked type. In the wound type, long sheet-shaped positive and negative electrodes coated with active material are wound with a separator between them. In the stacked type, multiple positive and negative electrodes are stacked sequentially with a separator between them.

[0005] In particular, pouch batteries, which are pouch-type batteries housed in pouch-type battery casings made of aluminum laminates, are increasingly being used due to their low manufacturing cost, light weight, and ease of retrofitting.

[0006] However, with the increase in energy density of battery cells in recent years, there is also a problem of increased gas generation inside the battery cells. In particular, if the gas generated inside the battery cell is not easily expelled, venting may occur due to gas generation within the battery cell. Furthermore, even if a separate venting section is included in the battery cell, moisture can still penetrate into the battery cell through the venting section, which may lead to battery performance degradation and additional gas generation due to the resulting side reactions. Therefore, there is an increasing need to develop a battery cell that can prevent external moisture from penetrating into the battery cell while improving the external emission of gases generated inside the battery cell. Summary of the Invention

[0007] Technical issues

[0008] This disclosure aims to provide a battery cell and a battery module including the battery cell, the battery cell being able to suppress the infiltration of external moisture into the battery cell while improving the external emission of gases generated inside the battery cell.

[0009] The objectives to be achieved by this invention are not limited to those described above. Those skilled in the art can clearly understand objectives not mentioned herein based on this specification and the accompanying drawings.

[0010] Technical solution

[0011] In one aspect of this disclosure, a battery cell is provided, the battery cell comprising: a battery housing 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 outer periphery of the battery housing; and a gas venting unit inserted into and fused together with the sealing portion, wherein the gas venting unit includes a first layer and a second layer and has a folded structure based on a first boundary line, the gas venting unit facing an internal opening of the battery housing, and the first layer forming the outer surface of the gas venting unit such that the first layer and the sealing portion are in contact with each other.

[0012] The first boundary line can extend along the width direction of the gas discharge unit.

[0013] In the gas discharge unit, the first end and the second end, which are located at both ends based on the first boundary line, can be folded toward the interior of the gas discharge unit based on the second boundary line, respectively.

[0014] The second boundary line can be in the diagonal direction that intersects with the first boundary line.

[0015] The first end and the second end can be positioned adjacent to the inside of the sealing portion.

[0016] The third end formed in the central portion of the gas exhaust unit can be configured to protrude beyond the sealing portion.

[0017] The fourth end of the outer end of the gas discharge unit, which is folded through the second boundary line, can be located on the sealing part.

[0018] The battery cell may further include: an electrode lead electrically connected to an electrode connector included in an electrode assembly and protruding beyond the battery housing via a sealing portion; and a lead film located at at least one of the upper and lower portions of the electrode lead corresponding to the sealing portion, wherein a gas venting unit may be located at the edge of the electrode lead in the sealing portion.

[0019] The first layer may contain at least one of polyolefin-based materials, epoxy resin, and polyvinyl chloride (PVC).

[0020] The second layer can contain fluorine-based materials.

[0021] The gas exhaust unit may also include a moisture-absorbing layer located between the first layer and the second layer.

[0022] The moisture-absorbing layer may include air-absorbing material.

[0023] The getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silicon dioxide (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca).

[0024] Getter materials can have a metal-organic framework (MOF) structure.

[0025] In another aspect of the invention, a battery module is also provided, which includes the battery cell described above.

[0026] Beneficial effects

[0027] According to the embodiments, this disclosure provides a battery cell including a gas exhaust unit having a multi-layer structure and folded based on a predetermined boundary line, and a battery module including the battery cell, thereby improving the external exhaust of gas generated inside the battery cell and suppressing moisture penetration into the battery cell.

[0028] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand, based on this specification and the accompanying drawings, the effects not mentioned herein. Attached Figure Description

[0029] Figure 1 This is a diagram illustrating a battery cell according to an embodiment of the present disclosure.

[0030] Figure 2 It is shown Figure 1 A magnified view of a portion of it.

[0031] Figure 3 It is shown Figure 1 A diagram showing the configuration of the gas exhaust unit.

[0032] Figure 4 It is shown Figure 1 A diagram of the folded structure of the gas exhaust unit.

[0033] Figure 5 It is along Figure 2 A partial cross-sectional view taken from the a-a' axis.

[0034] Figure 6 It is along Figure 2A partial cross-sectional view taken from the b-b' axis.

[0035] Figure 7 This is a diagram showing the configuration of a gas exhaust unit according to another embodiment of the present disclosure. Detailed Implementation

[0036] The present invention will now be described in detail with reference to various embodiments thereof, so as to enable those skilled in the art to readily implement it. The invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0037] To clearly illustrate the invention, parts irrelevant to the description have been omitted, and the same or similar parts are given the same reference numerals throughout the specification.

[0038] Furthermore, since the dimensions and thicknesses of each component shown in the accompanying drawings are arbitrarily represented for ease of description, this disclosure is not limited to the drawings. Thicknesses have been enlarged to clearly illustrate the various layers and regions in the drawings. Additionally, the thicknesses of some layers and regions have been exaggerated in the drawings for ease of illustration.

[0039] Furthermore, throughout the specification, when a section “includes” a component, it means that other components may also be included, rather than excluding other components, unless otherwise stated.

[0040] Additionally, throughout the instruction manual, when "top view" is mentioned, it means viewing the target part from above, while when "section view" is mentioned, it means viewing the vertical cut section of the target part from the side.

[0041] Figure 1 This is a diagram illustrating a battery cell according to an embodiment of the present disclosure.

[0042] Reference Figure 1 According to an embodiment of the present disclosure, the battery cell 100 includes: a battery housing 200 having a receiving portion 210 in which an electrode assembly 110 is mounted and a sealing portion 250 formed by sealing its outer periphery; and a gas venting unit 500 inserted into and fused together with the sealing portion 250. The sealing portion 250 can be sealed by heat, laser, or the like. Furthermore, the sealing portion 250 and the gas venting unit 500 can be fused together by heat, laser, or the like.

[0043] The battery casing 200 may be a laminate comprising a resin layer and a metal layer. More specifically, the battery casing 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.

[0044] The electrode assembly 110 may have a core-type (wound), laminated, or composite (laminated / folded) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator between the positive and negative electrodes.

[0045] Electrode leads 300 are electrically connected to electrode connectors (not shown) included in electrode assembly 110 and protrude beyond battery housing 200 via sealing portions 250. Additionally, lead films 400 are located in at least one of the upper and lower portions of electrode leads 300 corresponding to the sealing portions 250. Therefore, lead films 400 can improve the sealing performance of sealing portions 250 and electrode leads 300, while preventing short circuits in electrode leads 300 during fusion.

[0046] The lead film 400 may have a wider width than the electrode lead 300. The lead film 400 may have a longer length than the sealing portion 250, but a shorter length than the electrode lead 300. Therefore, the lead film 400 prevents the side surfaces of the electrode lead 300 from being exposed to the outside without interfering with the electrical connection of the electrode lead 300. In this specification, the width of the lead film 400 refers to the maximum distance between one end of the lead film 400 and the other end based on a direction perpendicular to the protrusion direction of the electrode lead 300, and the width of the electrode lead 300 refers to the maximum distance between one end of the electrode lead 300 and the other end based on a direction perpendicular to the protrusion direction of the electrode lead 300. The length of the lead film 400 refers to the maximum distance between one end of the lead film 400 and the other end based on the protrusion direction of the electrode lead 300, and the length of the sealing portion 250 refers to the maximum distance between one end of the sealing portion 250 and the other end based on the protrusion direction of the electrode lead 300. The length of electrode lead 300 refers to the maximum distance between one end of electrode lead 300 and the other end based on the protruding direction of electrode lead 300.

[0047] The gas venting unit 500 can be inserted into at least a portion of the sealing portion 250. More specifically, as... Figure 1 As shown, the gas venting unit 500 can be located in the outer periphery of the sealed portion 250 without the electrode lead 300. In other words, the gas venting unit 500 can be inserted into the sealed portion 250 adjacent to one side of the electrode assembly 110. Therefore, the gas venting unit 500 can sufficiently ensure the gas venting path of the gas venting unit 500 without interfering with the electrical connection of the electrode lead 300.

[0048] As another example, although not specifically shown in the accompanying drawings, the gas venting unit 500 may be located in the outer periphery of the sealing portion 250 where the electrode lead 300 is located. In other words, the gas venting unit 500 may be located in the same outer periphery as the electrode lead 300, but spaced apart from it. Therefore, since the gas venting unit 500 protrudes in the same direction as the electrode lead 300, it is advantageous to further improve the space efficiency of the battery cell 100.

[0049] The gas exhaust unit 500 will be described in more detail below.

[0050] Figure 2 It is shown Figure 1 A magnified view of a portion of it. Figure 3 It is shown Figure 1 A diagram showing the configuration of the gas exhaust unit. Figure 4 It is shown Figure 1 A diagram of the folded structure of the gas exhaust unit.

[0051] Reference Figure 2 and Figure 3 The gas exhaust unit 500 may include a first layer 510 and a second layer 550. More specifically, the gas exhaust unit 500 may be made of a thin film laminated with the first layer 510 and the second layer 550.

[0052] Here, the first layer 510 can be an adhesive layer that can be bonded by fusion. More specifically, the first layer 510 can include at least one of a polyolefin-based material, an epoxy resin, and polyvinyl chloride (PVC). For example, the polyolefin-based material can be polyethylene (PE), polypropylene (PP), etc.

[0053] Furthermore, the second layer 550 can be a non-adhesive layer that cannot be bonded by fusion. More specifically, the second layer 550 can include a fluorine-based material. For example, the fluorine-based material can be polytetrafluoroethylene (PTFE), polymethylpentene (TPX), etc.

[0054] Therefore, as Figure 2 and Figure 4 As shown, the gas discharge unit 500 has a structure in which a first layer 510 is folded to form the outer surface of the gas discharge unit 500, so that the first layer 510 is fused together with the sealing portion 250 to adhere to the sealing portion 250. Alternatively, a second layer 550 is folded to form the inner surface of the gas discharge unit 500, but the second layers 550 facing each other are not fused together, so that the interior of the gas discharge unit 500 can serve as a gas discharge channel.

[0055] The second layer 550 may have an adhesive material between the first layer 510 and the second layer 550, or it may be extruded together with the first layer 510. The adhesive material may include an acrylic-based material.

[0056] As gas is generated inside the battery and the internal pressure increases, the gas can be introduced into the interface between the two opposing second layers 550 to create a space between them. Due to the introduced gas, a pressure difference may occur between the space inside the gas exhaust unit 500 and the space outside the battery. This pressure difference can act as a driving force for the gas, thereby expelling the gas inside the gas exhaust unit 500 to the outside.

[0057] In this specification, air permeability can be measured by ASTM F2476-20.

[0058] The second layer (550) has an air permeability of 1.6e at 60℃. 5 Bale to 1.6e 7 For example, the carbon dioxide permeability only needs to meet the above-mentioned range. Furthermore, based on the thickness of the second layer 550 (200 μm), the permeability can meet the above-mentioned range at 60°C. If the permeability of the second layer 550 meets the above-mentioned range, the gas generated inside the battery cell can be discharged more effectively.

[0059] Reference Figure 4 , Figure 4 (a) is a diagram showing the boundary line along which the gas exhaust unit 500 is folded on the upper surface of the membrane on which the first layer 510 and the second layer 550 are laminated. Figure 4 (b) shows along Figure 4 A diagram showing the structure of the folded gas exhaust unit 500 along the boundary line of (a). However, in Figure 4 In the middle, the first layer 510 is shown as the center, located in Figure 4 The second layer 550 on the lower surface of (a) is not depicted, and is located in Figure 4 The gas discharge unit 500 on the inner surface of the gas discharge unit 500 in (b) is not depicted.

[0060] Reference Figure 2 and Figure 4 (a) The gas discharge unit 500 may have a folded structure based on a first boundary line A-A'. The first boundary line A-A' may extend along the width direction of the gas discharge unit 500. In this specification, the width direction of the gas discharge unit 500 refers to the longitudinal direction of the sealing portion 250. More specifically, as Figure 4 As shown in (a), the first boundary line A-A' can be the centerline of the first layer 510 and the second layer 550 laminated thereon based on the horizontal direction.

[0061] Therefore, the gas discharge unit 500 can be folded based on the first boundary line A-A', such that the first layer 510 can form the upper and lower surfaces of the gas discharge unit 500. That is, the sealing degree between the gas discharge unit 500 and the sealing portion 250 can be improved due to the first layer 510 located on the upper and lower surfaces of the gas discharge unit 500.

[0062] In addition, refer to Figure 4 The first end 500a and the second end 500b of the gas discharge unit 500, located at both ends based on the first boundary line A-A', can be folded inwards from the gas discharge unit 500 based on the second boundary lines B1-B1' and B2-B2', respectively. More specifically, as... Figure 4 As shown in (a), the second boundary lines B1-B1' and B2-B2' can be in the diagonal direction intersecting with the first boundary line A-A'.

[0063] Furthermore, the first end 500a and the second end 500b of the gas discharge unit 500 may be located inside the sealing portion 250. For example, as Figure 2 As shown, the first end 500a and the second end 500b of the gas exhaust unit 500 can be positioned adjacent to the inner side of the sealing portion 250. The inner side of the sealing portion 250 refers to the end of the sealing portion 250 closest to the electrode assembly.

[0064] Furthermore, the gas discharge unit 500 can adjust the angle between the second boundary lines B1-B1' and B2-B2' to change the positions of the first end 500a and the second end 500b. For example, the angle between the second boundary lines B1-B1' and B2-B2' can be less than 45°. When the angle between the second boundary lines B1-B1' and B2-B2' meets the above-mentioned range, the gas movement channel can be more easily ensured.

[0065] Furthermore, the gas discharge unit 500 can adjust the positions of the first end 500a and the second end 500b according to its insertion position into the sealing portion 250. (Refer to...) Figure 2 The fourth end 500d, which is the outer end of the gas discharge unit folded by the second boundary line, can be located on the sealing portion 250. That is, the fourth end 500d can be located between the outer and inner sides of the sealing portion 250. Here, the outer side of the sealing portion 250 refers to the end of the sealing portion 250 in the direction of the outer side of the battery. When the fourth end 500d is located on the sealing portion 250, it is easier to fix the gas discharge unit 500 to the sealing portion 250.

[0066] Therefore, the gas discharge unit 500 is folded based on the second boundary lines B1-B1' and B2-B2', so that the first layer 510 can form the side surface of the gas discharge unit 500. That is, since the first layer is located on both sides of the gas discharge unit 500, the sealing degree between the gas discharge unit 500 and the sealing portion 250 can be further improved.

[0067] Furthermore, since the second layer 550 is not exposed to the outside, it can prevent moisture from the outside of the battery cell 100 from penetrating into the interior. Additionally, since the gas exhaust unit 500 in this disclosure has a structure folded based on a predetermined boundary line, the manufacturing process is relatively easy.

[0068] The moisture permeability of the first layer 510, under conditions of 25°C and 50% RH, can be 0.02g to 0.2g, or 0.02g to 0.04g, or 0.06g, or 0.15g over 10 years. When the moisture permeability of the first layer 510 meets the above range, the penetration of moisture introduced from the gas exhaust unit 500 can be prevented more effectively.

[0069] In this specification, moisture permeability can be measured using the ASTM F 1249 method. In this case, moisture permeability can be measured using MCOON officially certified equipment.

[0070] However, in addition to Figure 4 In addition to the folded structure shown, the gas exhaust unit 500 of this disclosure may be included in this embodiment if the second layer 550 is folded in such a way that it is not exposed to the outside.

[0071] Figure 5 It is along Figure 2 A partial cross-sectional view taken from the a-a' axis. Figure 6 It is along Figure 2 A partial cross-sectional view taken from the b-b' axis.

[0072] Reference Figure 2 and Figure 5 In this embodiment, the gas venting unit 500 opens toward the interior of the battery housing 200, and the first layer 510 forms the outer surface of the gas venting unit 500, allowing the first layer 510 and the sealing portion 250 to contact each other. Furthermore, the second layer 550 forms the inner surface of the gas venting unit 500, and a gas venting channel 570 can be formed between the second layers 550.

[0073] Therefore, in this embodiment, the gas inside the battery cell 100 can be introduced into the gas discharge channel 570 formed between the second layers 550 of the gas discharge unit 500, and the gas introduced into the gas discharge channel 570 can be discharged to the outside according to the pressure difference with the outside.

[0074] The third end 500c formed in the central portion of the gas discharge unit 500 can protrude beyond the sealing portion 250. Furthermore, in this embodiment, the degree of gas discharge introduced into the gas discharge channel 570 can be adjusted according to the position of the third end 500c. For example, when the third end 500c is positioned adjacent to the outer side of the sealing portion 250, the area from which the gas introduced into the gas discharge channel 570 can be discharged is relatively small, thus reducing the degree of gas discharge. As another example, when the third end 500c is spaced apart from the outer side of the sealing portion 250, the area from which the gas introduced into the gas discharge channel 570 can be discharged is relatively large, thus increasing the degree of gas discharge.

[0075] The thickness of the gas discharge unit 500 can vary depending on the area through which the gas introduced into the gas discharge channel 570 can be discharged to the outside. The thickness of the gas discharge unit 500 can be determined by simultaneously considering gas permeability and sealing characteristics. For example, when the area through which the gas introduced into the gas discharge channel 570 can be discharged to the outside is very small, it may be more advantageous for the gas discharge unit 500 to be very thin while having sufficient thickness to fuse with the sealing portion 250 for gas discharge.

[0076] In one embodiment of this disclosure, the thickness of the first layer 510 can be from 10 μm to 50 μm. When the thickness of the first layer 510 meets the above range, the first layer 510 can be more easily fused with the sealing portion 250, and the gas generated inside the battery cell can be more easily discharged.

[0077] In one embodiment of the present invention, the thickness of the second layer 550 can be from 100 μm to 300 μm. When the thickness of the second layer 550 meets the above range, the gas generated inside the battery cell can be discharged more easily.

[0078] Reference Figure 2 and Figure 6 In this embodiment, the first end 500a and the second end 500b of the gas discharge unit 500 can be as follows: Figure 6 The gas exhaust unit 500 is shown to fold inwards. However, although the structure of the gas exhaust unit 500 is... Figure 6 The details are exaggerated, but the upper and lower parts of the gas exhaust unit 500 are fused together so that the first layer 510 on the outer surface of the gas exhaust unit 500 can contact each other, or the sealing portion 250 can be partially introduced between the first layers 510.

[0079] Therefore, the first layer 510 can be used as the outer surface on both sides of the gas discharge unit 500, thereby improving the sealing degree between the sealing portion 250 and the gas discharge unit 500. Furthermore, since the second layer 550 is not exposed to the outside, moisture from outside the battery unit 100 can be prevented from penetrating into the interior. Additionally, the area of ​​the second layer 550 formed on the inner surface of the gas discharge unit 500 can be relatively large, thereby increasing the amount of gas discharged into the gas discharge channel 570.

[0080] Figure 7 This is a diagram showing the configuration of a gas exhaust unit according to another embodiment of the present disclosure.

[0081] According to another embodiment of this disclosure, the gas exhaust unit 600 may include a first layer 610, a second layer 650, and a moisture-absorbing layer 690. Here, the moisture-absorbing layer 690 may be located between the first layer 610 and the second layer 650. More specifically, the gas exhaust unit 600 may be made of a film laminated with the first layer 610, the moisture-absorbing layer 690, and the second layer 650.

[0082] Here, the first layer 610 and the second layer 650 can be connected with the previously... Figures 1 to 6 The same method is used to describe it, so only the moisture-absorbing layer 690 will be described in detail below.

[0083] The moisture-absorbing layer 690 may be a layer with moisture-absorbing functionality. More specifically, the moisture-absorbing layer 690 may include a getter material. Here, the getter material can refer to a material capable of drawing air gases by utilizing the absorption of gases by a chemically activated metal membrane. For example, the getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silicon dioxide (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 to this and may include all kinds of materials generally classified as getter materials.

[0084] Therefore, refer to Figure 4 and Figure 7 The moisture-absorbing layer 690 is located between the first layer 610 and the second layer 650, and the gas exhaust unit 500 can further minimize the permeation of moisture introduced into the battery cell 100 from the outside of the battery cell 100, and the gas is more easily discharged to the outside due to its high air permeability.

[0085] Furthermore, a battery module according to another embodiment of this disclosure includes the aforementioned battery cells. Additionally, one or more battery modules according to this embodiment can be encapsulated in a battery pack housing to form a battery pack.

[0086] The aforementioned battery module and battery pack including the battery module can be applied to various devices. These devices can be vehicles such as electric bicycles, electric cars, hybrid electric vehicles, etc., but this disclosure is not limited thereto, and this disclosure can be applied to various devices that can use the battery module and battery pack including the battery module, which is also within the scope of the claims of this disclosure.

[0087] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples illustrate preferred embodiments of this disclosure, they are given by way of illustration only, as various variations and modifications within the scope of this disclosure will become apparent to those skilled in the art based on the detailed description.

Claims

1. A battery cell comprising: a battery case having an accommodation portion in which an electrode assembly is installed and a sealing portion formed by sealing an outer circumference of the battery case; and a gas discharge unit inserted into the sealing portion and fused together with the sealing portion, wherein the gas discharge unit comprises a first layer and a second layer and is made of a film in which the first layer and the second layer are laminated, wherein the gas discharge unit has a structure in which the first layer is folded to become an outer surface of the gas discharge unit and the second layer is folded to become an inner surface of the gas discharge unit, but second layers facing each other are not fused to each other, wherein the first layer and the second layer are folded based on a first boundary line in such a way that the second layer is not exposed to the outside, the gas discharge unit is open toward an inside of the battery case, and the first layer and the sealing portion are in contact with each other. 2.The battery cell of claim 1, the first boundary line extends in a width direction of the gas discharge unit. wherein 3.The battery cell of claim 2, in the gas discharge unit, first and second end portions located at both ends based on the first boundary line are folded toward an inside of the gas discharge unit based on a second boundary line, respectively. wherein 4.The battery cell of claim 3, the second boundary line is in a diagonal direction intersecting the first boundary line. wherein 5.The battery cell of claim 3, the first end portion and the second end portion are positioned adjacent to an inside of the sealing portion. wherein 6.The battery cell of claim 5, the inside of the sealing portion refers to an end portion of the sealing portion that is close to the electrode assembly. wherein 7.The battery cell of claim 1, a third end portion formed in a central portion of the gas discharge unit is configured to protrude outside the sealing portion. wherein 8.The battery cell of claim 4, a fourth end portion that is an outer end portion of the gas discharge unit folded by the second boundary line is located on the sealing portion. wherein 9.The battery cell of claim 1, further comprising: an electrode lead wire electrically connected to an electrode tab included in the electrode assembly and protruding outside the battery case via the sealing portion; and a lead wire 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 wire, wherein the gas discharge unit is located at an edge of the sealing portion where the electrode lead wire is not present. 10.The battery cell of claim 1, the first layer includes at least one of a polyolefin-based material, an epoxy resin, and polyvinyl chloride (PVC). 11.The battery cell of claim 1, wherein the second layer includes a fluorine-based material. 12.The battery cell of claim 11, wherein, 13.The battery cell of claim 1, ​ wherein The second layer has an air permeability of 1.6 e 5 Baller to 1.6 e 7 Baller. ​ wherein The gas discharging unit further includes a moisture absorbing layer between the first layer and the second layer.

14. The battery cell of claim 13, wherein The moisture absorbing layer includes a getter material.

15. The battery cell of claim 14, wherein The getter material includes at least one of calcium oxide CaO, lithium chloride LiCl, silicon dioxide SiO2, barium oxide BaO, barium Ba, and calcium Ca.

16. The battery cell of claim 14, wherein The getter material has a structure of a metal organic framework MOF.

17. A battery module comprising the battery cell according to any one of claims 1 to 16.

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