Battery cell and battery module including the battery cell

Abstract

A battery cell is disclosed, which includes a battery case having a receiving portion for mounting an electrode assembly and a sealing portion for sealing the periphery of the battery case; an electrode lead electrically connected to an electrode terminal 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 in at least one of an upper portion and a lower portion of the electrode lead. The lead film has a recessed portion recessed in the outer direction of the battery case, the recessed portion is open toward the inner side of the battery case, and a sealing portion located on a gas discharge portion of the recessed portion has a recessed sealing portion recessed inwardly at the outer side of the battery case, and the recessed sealing portion overlaps at least a portion of the gas discharge portion in a top view.

Description

Technical Field

[0001] The present disclosure relates to a battery cell and a battery module including the same, and more particularly, to a battery cell that improves the amount of external discharge of gas generated in the battery cell and a battery module including the same.

[0002] This application claims priority to Korean Patent Application No. 10-2022-0018745 filed in Korea on February 14, 2022, the disclosure of which is incorporated herein by reference. Background Art

[0003] With the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as energy sources has increased rapidly. Specifically, secondary batteries have attracted widespread attention not only as energy sources for mobile devices such as mobile phones, digital cameras, notebook computers, and wearable devices, but also as energy sources for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0004] According to the shape of the battery case, these secondary batteries are classified into cylindrical batteries and square batteries in which the electrode assembly is included in a cylindrical or square metal hard shell, and soft-pack batteries in which the electrode assembly is included in a soft-pack case of an aluminum laminate sheet. Here, the electrode assembly included in the battery case is an electric element including a positive electrode, a negative electrode, and a separator inserted between the positive electrode and the negative electrode, and is capable of charging and discharging, and is classified into a winding type in which a long sheet-type positive electrode and a negative electrode coated with an active material are wound and a separator is inserted between the long sheet-type positive electrode and the negative electrode, and a stacking type in which a plurality of positive electrodes and negative electrodes are stacked in sequence and a separator is inserted between the positive electrode and the negative electrode.

[0005] In particular, among these batteries, a pouch-type battery in which a stacked or stacked / folded type electrode assembly is included in a pouch-type battery case made of an aluminum laminate sheet is being increasingly used due to low manufacturing cost, light weight, and ease of change.

[0006] Figure 1 1 is a top view showing a battery cell of the related art. Figure 2 It is along Figure 1 A cross-sectional view taken along the line a-a'. Figure 1 and Figure 2 The battery cell 10 of the related art includes a battery case 20 having a receiving portion 21 for mounting an electrode assembly 11 and a sealing portion 25 for sealing the periphery of the battery case 20. Here, the battery cell 10 includes an electrode lead 30 protruding to the outside of the battery case 20 through 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.

[0007] However, as the energy density of battery cells has increased in recent years, there is a problem that the amount of gas generated inside the battery cells has also increased. In the case of the battery cell 10 of the prior art, a component capable of discharging the gas generated inside the battery cell is not included, so a degassing phenomenon may occur in the battery cell due to the generation of gas. In addition, moisture may penetrate into the battery cell damaged by the 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 outer discharge of the gas generated inside the battery cell. Summary of the invention

[0008] Technical issues

[0009] The present disclosure is directed to providing a battery cell in which an amount of gas generated in the battery cell is improved to be discharged outside, and a battery module including the battery cell.

[0010] 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 based on the present specification and the accompanying drawings.

[0011] Technical Solution

[0012] In one aspect of the present disclosure, a battery cell is provided, comprising: a battery case having a housing portion for mounting an electrode assembly and a sealing portion for sealing the periphery of the battery case; 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 in at least one of an upper portion and a lower portion of the electrode lead, wherein the lead film has a recessed portion recessed in the outer direction of the battery case, the recessed portion being open toward the inner side of the battery case, and a sealing portion located on a gas discharge portion of the recessed portion having a recessed sealing portion recessed inwardly at the outer side of the battery case, and in a top view, the recessed sealing portion overlaps with at least a portion of the gas discharge portion.

[0013] The gas discharge portion of the recessed portion may be exposed to the outside of the battery case.

[0014] The recessed portion may include a first recessed portion and a second recessed portion, the first recessed portion may extend along a protruding direction of the electrode lead, and the second recessed portion may extend along a length direction of the sealing portion.

[0015] One end of the first recessed portion may be open toward the inside of the battery case, and the other end of the first recessed portion may be in communication with the second recessed portion.

[0016] The recessed sealing portion may be located on the second recessed portion.

[0017] The recessed sealing portion may extend along a length direction of the second recessed portion.

[0018] The length of the recessed sealing portion may be equal to or greater than the length of the second recessed portion.

[0019] The width of the recessed sealing portion may be equal to or greater than the width of the second recessed portion.

[0020] The lead film may have an air permeability of 20 bar to 60 bar at 60°C.

[0021] The lead film may have a water permeability of 0.02 g to 0.2 g at 25° C., 50% RH for 10 years.

[0022] The lead film may include a polyolefin-based material.

[0023] A venting layer may be inserted into the venting layer recess, and the venting layer may include a material having higher air permeability than the lead film.

[0024] The degassing layer may have a thickness of 50 μm to 150 μm.

[0025] The exhaust layer can have 1.6e 5 bar to 1.6e 7 The breathability of the bar.

[0026] The exhaust layer may include polyolefin-based resin, fluorine-based resin, natural material, glass fiber, ceramic fiber, metal fiber, or two or more of the foregoing materials.

[0027] The battery cell may further include an inner layer configured to cover at least one inner surface of the recessed portion of the lead film.

[0028] The melting point of the material of the inner layer may be higher than that of the material of the lead film, and the material of the inner layer may not react with the electrolyte.

[0029] The inner layer may include at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material.

[0030] The width of the lead film covering the front surface of the recessed portion may be 2 mm or more based on the protruding direction of the electrode lead.

[0031] The thickness of the lead film covering the upper surface of the recessed portion may be 100 μm to 300 μm.

[0032] Another aspect of the present disclosure provides a battery module including the above-mentioned battery cell.

[0033] Beneficial Effects

[0034] According to an embodiment, the present disclosure provides a battery cell including an electrode lead to which a lead film having a recessed portion recessed in the outer direction of a battery case and open toward the inner side of the battery case is attached, and a battery module including such a battery cell, so that the outer side discharge amount of the gas generated inside the battery cell can be increased.

[0035] In addition, according to an embodiment, in the present disclosure, a sealing portion located on a gas discharge portion of a recessed portion includes a recessed sealing portion that is recessed inward at an outer portion of a battery housing and overlaps with at least a portion of the gas discharge portion in a top view, thereby increasing the amount of gas discharged to the outside of the battery cell that is generated inside the battery cell.

[0036] The effects of the present disclosure are not limited to the above effects, and effects not set forth herein will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 1 is a top view showing a battery cell of the related art.

[0038] Figure 2 It is along Figure 1 A cross-sectional view taken along line a-a'.

[0039] Figure 3 is a top view showing a battery cell according to an embodiment of the present disclosure.

[0040] Figure 4 It is shown that the Figure 3 A perspective view of the electrode leads in a battery cell.

[0041] Figure 5 It is along Figure 4 A cross-sectional view taken along line c-c'.

[0042] Figure 6 It is along Figure 4 A cross-sectional view taken along line d-d'.

[0043] Figure 7 1 is an enlarged view showing an electrode lead portion according to an embodiment of the present disclosure.

[0044] Figure 8 is an enlarged view showing an electrode lead portion of another embodiment of the present disclosure.

[0045] Fig. 9 It is along Figure 3 A cross-sectional view taken along line b-b'.

[0046] Fig.10 In another embodiment of the present disclosure, Figure 3 A cross-sectional view taken along line b-b'. DETAILED DESCRIPTION

[0047] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. The present disclosure can be implemented in various different forms and is not limited to the embodiments described herein.

[0048] In order to clearly illustrate the present disclosure, parts irrelevant to the description are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0049] In addition, since the sizes and thicknesses of the various components 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 the various layers and regions in the drawings, the thicknesses are exaggerated. In addition, in the drawings, for the convenience of description, the thicknesses of some layers and regions are enlarged.

[0050] In addition, when a part such as a layer, film, region, plate, etc. is interpreted as being located “on” or “over” another part, this includes not only the case where the part is “directly” located “on” another part, but also the case where another part is interposed therebetween. Conversely, when the part is interpreted as being “directly” located “on” another part, this means that no other part exists therebetween. In addition, when a part is interpreted as being located “over” or “on” a reference part, this means that the part is located above or below the reference part, and does not necessarily mean that the part is located “over” or “on” the reference part in a direction opposite to gravity.

[0051] In addition, throughout the specification, when a part “includes” specific components, it means that other components may also be included without excluding the other components unless otherwise specified.

[0052] In addition, throughout the specification, when referred to as a “top view”, this means that the target portion is viewed from above, and when referred to as a “cross-sectional view”, this means that a vertically cut section of the target portion is viewed from the side.

[0053] Hereinafter, a soft pack type battery cell 100 according to an embodiment of the present disclosure will be described. However, here, description will be made based on one of both sides of the soft pack type battery cell 100, but is not necessarily limited thereto, and in the case of the other side, the same or similar content may be described.

[0054] Figure 3 is a top view showing a battery cell according to an embodiment of the present disclosure.

[0055] Reference Figure 3 , a battery cell 100 according to an embodiment of the present disclosure includes a battery case 200 , an electrode lead 300 , and a lead film 400 .

[0056] The battery case 200 includes a housing 210 for housing the electrode assembly 110 and a sealing portion 250 for sealing the periphery of the battery case 200. The sealing portion 250 may be sealed by heat or laser. The battery case 200 may be a laminated sheet including a resin layer and a metal layer. More specifically, the battery case 200 may be made of a laminated sheet and may include an outer resin layer forming the outermost layer, a barrier metal layer to prevent penetration of materials, and an inner resin layer for sealing.

[0057] In addition, the electrode assembly 110 may have a wound type (winding type), stacked type (laminated type) or composite type (stacked / folded type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode.

[0058] Hereinafter, the electrode lead 300 and the lead film 400 will be mainly described.

[0059] Figure 4 It is shown that the Figure 3 A perspective view of the electrode leads in a battery cell.

[0060] 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 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 in at least one of the upper and lower parts of the electrode lead 300. Therefore, the lead film 400 can improve the sealing performance of the sealing part 250 and the electrode lead 300, and prevent a short circuit from occurring in the electrode lead 300 during sealing.

[0061] Figure 5 It is along Figure 4 A cross-sectional view taken along line c-c'. Figure 6 It is along Figure 4 A cross-sectional view taken along line d-d'.

[0062] Reference Figure 5 and Figure 6 The lead film 400 has a recessed portion 450 recessed in the outer direction of the battery case 200, and the recessed portion 450 is open toward the inner side of the battery case 200. In addition, the inner surface of the recessed portion 450 may be closed based on the protruding direction of the electrode lead 300.

[0063] In addition, refer to Figure 5 and Figure 6 The lead film 400 may further include an inner layer 410 covering at least one inner surface of the recessed portion 450 .

[0064] For example, refer to Figure 5 (a) and Figure 6 (a), in the recessed portion 450, the inner layer 410 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 recessed portion 450 except for the open surface.

[0065] Therefore, even if the lead film 400 is sealed with the sealing part 250 in a state of being located on at least one of the upper and lower parts of the electrode lead 300 , the recessed part 450 may be maintained in an unsealed state by the inner layer 410 .

[0066] As another example, see Figure 5 (b) and Figure 6 (b), the inner layer 410 may cover the upper surface and the lower surface of the inner surface of the recessed part 450. That is, the inner layer 410 may be formed on at least one of the upper surface and the lower surface of the recessed part 450 facing each other.

[0067] Therefore, while minimizing the inner layer 410 formed in the recessed portion 450 of the lead film 400, the recessed portion 450 can be maintained in an unsealed state by the inner layer 410. In addition, the manufacturing process can be simplified and the cost can be reduced.

[0068] More specifically, the inner layer 410 may be made of a material having a higher melting point than that of the material of the lead film 400. In addition, the inner layer 410 may be made of a material that does not react with the electrolyte included in the battery case 200. Therefore, since the inner layer 410 is made of the above material, the recessed portion 450 may maintain or retain a cavity without reacting with the electrolyte, and during the sealing process, heat melting, heat deformation, etc. may not be caused. In addition, the gas generated in the battery case 200 may be easily discharged to the outside.

[0069] In an embodiment of the present disclosure, the inner layer 410 may have a thickness of 100 μm or less.

[0070] In an embodiment of the present disclosure, the air permeability of the inner layer 410 may be greater than or equal to 40 bar. For example, the carbon dioxide permeability of the inner layer 410 may satisfy the above range.

[0071] For example, the lead film 400 may include a polyolefin-based material, and the inner layer 410 may include at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material. For example, the lead film 400 may include at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material that meets the above permeability value. The polyolefin-based material may include at least one material selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). The fluorine-based material may include at least one material selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride. In addition, the inner layer 410 includes an air-intake material so that air permeability can be increased and water permeability can be minimized. For example, the air-intake material may be calcium oxide (CaO), barium oxide (BaO), lithium chloride (LiCl), silicon dioxide (SiO2), etc., but is not limited thereto, and any material (H2O) that reacts with water can be used.

[0072] The inner layer 410 may include an adhesive material between the lead film 400 and the inner layer 410, or may be pressed together with the lead film 400 to be bonded to the lead film 400. The adhesive material may include an acrylic adhesive material. Specifically, when the inner layer 410 is pressed together with the lead film 400, the air permeability of the inner layer 410 may be 40 bar or more.

[0073] Reference Figures 4 to 6 , the lead film 400 includes a first lead film and a second lead film, the first lead film may be located above the electrode lead 300, and the second lead film may be located below the electrode lead 300. At this time, the electrode lead 300 is sealed with the sealing part 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.

[0074] 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 performance of the sealing part 250 .

[0075] For example, in the lead film 400, the recessed portion 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 recessed portion 450 may be formed on the first lead film or the second lead film based on the electrode lead 300, or the recessed portion 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 recessed portions 450 is not limited to the above number, and the recessed portions 450 may be formed in the lead film 400 in an appropriate number.

[0076] Therefore, the durability and airtightness of the lead film 400 can be controlled by adjusting the number of recessed parts 450 formed in the lead film 400. In addition, if necessary, the number of recessed parts 450 can be minimized to simplify the manufacturing process and reduce costs.

[0077] In one embodiment of the present disclosure, the air permeability of the lead film 400 at 60°C may be 20 bar to 60 bar or 30 bar to 40 bar. For example, the carbon dioxide 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 air permeability at 60°C may satisfy the above range. If the air permeability of the lead film 400 satisfies the above range, the gas generated inside the secondary battery can be more effectively discharged.

[0078] In this specification, air permeability may be measured by ASTM F2476-20.

[0079] In one embodiment of the present disclosure, the water permeability of the lead film 400 at 25°C and 50% RH for 10 years may be 0.02g to 0.2g, or 0.02g to 0.04g, or 0.06g, or 0.15g. If the water permeability of the lead film 400 meets the above range, moisture can be more effectively prevented from penetrating the lead film 400.

[0080] In this specification, the water permeation can be measured by adopting the ASTM F1249 method. At this time, the water permeation can be measured using an apparatus officially certified by MCOON.

[0081] In an embodiment of the present disclosure, the lead film 400 may have an air permeability of 20 bar to 60 bar at 60° C., and the lead film 400 may have a water permeability of 0.02 g to 0.2 g at 25° C., 50% RH for 10 years. When the air permeability and water permeability of the lead film 400 satisfy the above ranges, it is possible to more effectively prevent moisture from penetrating from the outside while discharging the gas generated inside the secondary battery.

[0082] In an 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 air permeability and / or water permeability values. The polyolefin-based resin may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). The lead film 400 includes polypropylene, and the air permeability of the lead film 400 at 60°C may be 20 bar to 60 bar. In addition, the water permeability may be 0.06g to 0.15g. In this case, the gas generated inside the secondary battery is more effectively discharged, and it is easier to prevent moisture from penetrating from the outside.

[0083] 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 leakage of the inner electrolyte.

[0084] Figure 7 1 is an enlarged view showing an electrode lead portion according to an embodiment of the present disclosure.

[0085] Reference Figure 7 , the recessed sealing portion 250H is recessed inward from the outside of the battery case 200. More specifically, the recessed sealing portion 250H may be recessed inward at the outside of the accommodation portion 210 in the sealing portion 250.

[0086] In addition, refer to Figure 7 , a recessed sealing portion 250H is formed on the gas discharge portion of the recessed portion 450 .

[0087] When the gas generated in the battery case 200 is discharged to the outside of the battery case 200 through the recessed portion 450, if the sealing portion 250 contacts the gas discharge portion, the sealing portion 250 prevents the gas from being discharged to the outside of the battery case 200. Therefore, there is a problem that the amount of gas discharged to the outside of the battery case 200 is greatly reduced. For example, the gas inside the recessed portion 450 can be discharged to the outside of the battery case 200 through the gas permeation of the lead film on the upper surface of the recessed end of the recessed portion 450 in the lead film 400. Here, if the lead film 400 on the upper surface of the recessed end of the recessed portion 450 contacts the sealing portion 250, the gas discharge from the recessed portion 450 to the outside of the battery case 200 may be blocked by the sealing portion 250.

[0088] Reference Figure 7 , the recessed sealing portion 250H is located on the gas discharge portion of the recessed portion 450, so that at least a portion of the gas discharge portion does not overlap with the sealing portion 250 in a top view. Here, at least a portion of the gas discharge portion does not overlap with the sealing portion 250 in a top view means that when the battery case 200 is viewed from above, at least a portion of the gas discharge portion does not overlap with the sealing portion 250. In other words, interference between the gas discharge portion of the recessed portion 450 and the sealing portion 250 in the lead film 400 can be avoided.

[0089] Reference Figure 7 The recessed portion 450 may include a first recessed portion 451 and a second recessed portion 455, the first recessed portion 451 may extend along the protruding direction of the electrode lead 300, and the second recessed portion 455 may extend along the length direction of the sealing portion 250. Here, the length direction of the sealing portion 250 refers to a direction orthogonal to the protruding direction of the electrode lead 300.

[0090] However, the shape of the recessed portion 450 is not limited to the above shape, and the recessed portion 450 may be formed in an appropriate shape in the lead film 400 .

[0091] Here, one end of the first recessed portion 451 is open toward the inside of the battery housing 200, and the other end of the first recessed portion 451 can be connected to the second recessed portion 455. More specifically, the first recessed portion 451 and the second recessed portion 455 can be formed integrally with each other. That is, the first recessed portion 451 can be used as a gas inlet for the gas inside the battery housing 200 to introduce the recessed portion 450, and the second recessed portion 455 can be used as a gas outlet for exhausting gas.

[0092] In addition, refer to Figure 7 , the recessed sealing portion 250H may be located on the second recessed portion 455. As another example, the recessed sealing portion 250H may also be located on a boundary line between the first recessed portion 451 and the second recessed portion 455.

[0093] More specifically, the recessed seal portion 250H may extend along the length direction of the second recessed portion 455. Here, the length of the second recessed portion 455 indicates the maximum value of the distance between one end and the other end of the second recessed portion 455 in a direction orthogonal to the protruding direction of the electrode lead 300. In addition, the length of the recessed seal portion 250H may be equal to or greater than the length of the second recessed portion 455. Here, the length of the recessed seal portion 250H indicates the maximum value of the distance between one end and the other end of the recessed seal portion 250H in a direction orthogonal to the protruding direction of the electrode lead 300.

[0094] In addition, the width of the recessed seal portion 250H may be equal to or greater than the width of the second recessed portion 455. Here, the width of the second recessed portion 455 represents the maximum value of the distance between one end and the other end of the second recessed portion 455 in the protruding direction of the electrode lead 300. Here, the width of the recessed seal portion 250H represents the maximum value of the distance between one end and the other end of the recessed seal portion 250H in the protruding direction of the electrode lead 300.

[0095] However, the size of the recessed sealing portion 250H is not limited to the above size, and the recessed sealing portion 250H may be formed in an appropriate size in the lead film 400 .

[0096] Therefore, in the lead film 400, the lead film 400 on the second recessed portion 455 may not contact the sealing portion 250. In other words, interference between a portion of the lead film 400 where the second recessed portion 455 is located and the sealing portion 250 may be avoided.

[0097] Reference Figure 7 , in the lead film 400 , the recessed parts 450 may be formed at various positions based on the electrode lead 300 .

[0098] For example, Figure 7As shown in (a), in the lead film 400, the recessed portion 450 may be located on the electrode lead 300. More specifically, the recessed portion 450 may be formed at a position corresponding to the center of the electrode lead 300.

[0099] As another example, Figure 7 As shown in (b), the length of the lead film 400 may be greater than the width of the electrode lead 300, and the recessed portion 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 represents 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 represents 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 recessed portion 450 may be formed at a position avoiding the electrode lead 300. However, the position of the recessed portion 450 is not limited to the above position, and the recessed portion 450 may be formed at an appropriate position in the lead film 400.

[0100] Therefore, the durability and airtightness of the lead film 400 can be controlled by adjusting the position of the recessed portion 450 formed on the lead film 400. In addition, if necessary, the size of the recessed portion 450 can be adjusted according to the position of the recessed portion 450, thereby simplifying the manufacturing process and reducing costs.

[0101] Figure 8 is an enlarged view showing an electrode lead portion of another embodiment of the present disclosure.

[0102] Reference Figure 8 The concave sealing part 250H may be provided in plurality, and the plurality of concave sealing parts 250H may be spaced apart from each other. Since the plurality of concave sealing parts 250H are spaced apart from each other, the sealing part 250 of the gas discharge part of the lead film 400 may be sealed in a concave-convex shape.

[0103] Since the recessed sealing portion 250H has the above structure, it is possible to more easily prevent substances outside the battery, such as moisture, from penetrating from the gas discharge portion of the lead film 400 that does not interfere with the sealing portion 250 .

[0104] Fig. 9 It is along Figure 3 A cross-sectional view taken along line b-b'.

[0105] Reference Fig. 9When the pressure exceeds a predetermined level, the gas generated inside the battery cell 100 may be discharged to the recess 450. Here, since the recess 450 is open toward the inside of the battery case 200, the pressure inside the recess 450 may be the same as the pressure inside the battery case 200.

[0106] The pressure inside the recessed portion 450 is higher than the pressure outside the battery cell 100, and the resulting pressure difference can be used as a driving force for the gas. Therefore, the gas introduced into the recessed portion 450 can be easily discharged to the outside. In addition, the amount of gas generated inside the battery cell 100 discharged outside can also be increased.

[0107] At this time, the gas generated inside the battery case 200 may be discharged along the Z-axis direction through the recessed portion 450 and the lead film 400 covering the upper surface of the recessed portion.

[0108] In addition, since the recessed portion 450 is open toward the inside of the battery case 200 and the inner surface of the recessed portion 450 recessed toward the outside of the battery case 200 is closed, the airtightness and durability of the soft pack can also be ensured.

[0109] At this time, the concave end of the recess 450 can be used as a gas outlet for discharging the gas introduced into the recess 450 to the outside, and the end of the recess 450 open to the inside of the battery case 200 can be used as a gas inlet for introducing the gas generated in the battery case 200.

[0110] Reference Fig. 9 A recessed sealing portion 250H is formed on the gas discharge portion of the recessed portion 450 .

[0111] Reference Fig. 9 , in the lead film 400, the gas discharge portion of the recessed portion 450 may be exposed to the outside of the battery case 200. In this specification, the outside of the battery case 200 refers to an area of ​​the sealing portion 250 that is further outside than the battery case 200 based on the outer end of the battery case. In this case, in the lead film 400, the area of ​​the recessed portion 450 where the gas discharge portion is exposed to the outside of the battery case 200 increases, so that the gas can be discharged to the outside of the battery case 200 more smoothly.

[0112] In an embodiment of the present disclosure, the second recessed portion 455 may be exposed to the outside of the battery case 200. When the area of ​​the lead film 400 where the second recessed portion 455 is exposed to the outside of the battery case 200 increases, the gas inside the battery case 200 may be smoothly discharged to the outside of the battery case 200.

[0113] Reference Fig. 9, the thickness H of the lead film 400 covering the upper surface of the recessed portion 450 may be 100 μm to 300 μm or 100 μm to 200 μm. When the thickness H of the lead film 400 covering the upper surface of the recessed portion 450 satisfies the above range, the gas inside the battery case 200 can be more easily discharged to the outside.

[0114] Reference Fig. 9 , based on the protruding direction of the electrode lead 300, the width W of the lead film 400 covering the front surface of the recessed portion 450 may be 2 mm or more or 2 mm to 3 mm. Here, the width of the lead film 400 surrounding the front surface of the recessed portion 450 represents the maximum value of the distance between the concave end of the recessed portion 450 and the outer end of the lead film 400 of the battery case 200. When the width W of the lead film 400 surrounding the front surface of the recessed portion 450 satisfies the above range, it is easier to prevent the lead film 400 from being torn in the process of discharging the gas generated inside the battery case 200 to the outside.

[0115] Fig.10 In another embodiment of the present disclosure, Figure 3 A cross-sectional view taken along line b-b'.

[0116] Reference Fig.10 , a venting layer 500 may be inserted into the recessed portion 450. The venting layer 500 includes a material having a higher air permeability than the lead film 400. Higher air permeability may mean that when a gas having a predetermined pressure passes through in one direction, the amount of air permeability is relatively larger. When the venting layer 500 is inserted into the recessed portion 450, even if the pressure is not higher than the predetermined pressure, the gas generated inside the battery housing 200 may be introduced into the recessed portion 450 through the venting layer 500 having high air permeability, so that the gas inside the battery may be more easily discharged to the outside of the battery.

[0117] For example, the exhaust layer 500 may include a material that is more porous than the lead film 400. That is, the exhaust layer 500 may include a material that has a higher porosity than the lead film 400.

[0118] In the embodiment of the present disclosure, the air permeability of the exhaust layer 500 may be 1.6e 5 bar to 1.6e 7 Ba or 1e 6 Ba to 3e 6 For example, the carbon dioxide permeability of the exhaust layer 500 may satisfy the above range.

[0119] In an embodiment of the present disclosure, the exhaust layer 500 may include one or more materials selected from the group consisting of polyolefin-based resins, fluorine-based resins, natural materials, glass fibers, ceramic fibers, and metal fibers. For example, the exhaust layer 500 may include one or more materials selected from the group consisting of polyolefin-based resins, fluorine-based resins, natural materials, glass fibers, ceramic fibers, and metal fibers that meet the above air permeability values. The polyolefin-based resin may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). The fluorine-based resin may include one or more materials selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride, and the natural material may include one or more materials selected from the group consisting of cotton and wool.

[0120] In an embodiment of the present disclosure, the exhaust layer 500 may have a thickness of 50 to 150 μm or 50 to 100 μm. When the thickness of the exhaust layer 500 satisfies the above range, the gas generated inside the battery case 200 may be more easily introduced into the recess 450 .

[0121] In an embodiment of the present disclosure, the venting layer 500 may include a material that is stable in an electrolyte environment (i.e., does not react with the electrolyte inside the battery housing 200). For example, the venting layer 500 may include one or more materials selected from the group consisting of polypropylene, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene.

[0122] 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.

[0123] The battery module and the battery pack including the battery module can be applied to various devices. These devices can be transportation devices 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 rights of the present disclosure.

[0124] Although the preferred embodiments of the present disclosure have been described in detail above, the scope of the 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 the rights of the present disclosure.

[0125] Description of Reference Numerals

[0126] 100: Battery cell

[0127] 110: Electrode assembly

[0128] 200: Battery housing

[0129] 210: Accommodation

[0130] 250: Sealing part

[0131] 250H: Recessed seal

[0132] 300: Electrode lead

[0133] 400: Lead film

[0134] 410: Inner layer

[0135] 450: Depression

[0136] 451: First recessed portion

[0137] 455: Second recessed portion

[0138] 500: Exhaust layer

Claims

1. A battery cell, comprising: A battery case having a receiving portion for mounting the electrode assembly and a sealing portion for sealing an outer periphery of the battery case; an electrode lead which is electrically connected to an electrode tab included in the electrode assembly and protrudes to the outside of the battery case through 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 the lead film has a recessed portion that is recessed in the outer direction of the battery housing, The recessed portion is open toward the inner side of the battery housing, The sealing portion on the gas discharge portion of the recessed portion has a recessed sealing portion recessed inwardly at the outer side of the battery case, and The recessed sealing portion overlaps at least a portion of the gas discharge portion in a plan view.

2. The battery cell according to claim 1, wherein: The gas discharge portion of the recessed portion is exposed to the outside of the battery case.

3. The battery cell according to claim 1, wherein: The recessed sealing portion is provided in plurality, and the plurality of recessed sealing portions are spaced apart from each other.

4. The battery cell according to claim 1, wherein: The recessed portion includes a first recessed portion and a second recessed portion, The first recessed portion extends along a protruding direction of the electrode lead, and The second recessed portion extends along a length direction of the sealing portion.

5. The battery cell according to claim 4, wherein: One end of the first recessed portion is open toward the inside of the battery case, and the other end of the first recessed portion is communicated with the second recessed portion.

6. The battery cell according to claim 4, wherein: The recessed sealing portion is located on the second recessed portion.

7. The battery cell according to claim 6, wherein: The recessed sealing portion extends along a length direction of the second recessed portion.

8. The battery cell according to claim 7, wherein: The length of the recessed sealing portion is equal to or greater than the length of the second recessed portion.

9. The battery cell according to claim 6, wherein: The width of the recessed sealing portion is equal to or greater than the width of the second recessed portion.

10. The battery cell according to claim 1, wherein: The lead film has an air permeability of 20 bar to 60 bar at 60°C.

11. The battery cell according to claim 1, wherein: The lead film has a water permeability of 0.02 g to 0.2 g at 25° C. and 50% RH for 10 years.

12. The battery cell according to claim 1, wherein: The lead film includes a polyolefin-based material.

13. The battery cell according to claim 1, wherein: A venting layer is inserted into the recessed portion, and The exhaust layer includes a material having higher air permeability than the lead film.

14. The battery cell according to claim 13, wherein: The degassing layer has a thickness of 50 μm to 150 μm.

15. The battery cell according to claim 13, wherein: The exhaust layer has 1.6e 5 bar to 1.6e 7 The breathability of the bar.

16. The battery cell according to claim 13, wherein: The degassing layer includes polyolefin-based resin, fluorine-based resin, natural material, glass fiber, ceramic fiber, metal fiber, or two or more of the foregoing materials.

17. The battery cell according to claim 1, further comprising: The inner layer is configured to cover at least one inner surface of the recessed portion of the lead film.

18. The battery cell according to claim 17, wherein: The material of the inner layer has a higher melting point than the material of the lead film, and the material of the inner layer does not react with an electrolyte.

19. The battery cell according to claim 18, wherein: The inner layer includes at least one of a polyolefin-based material, a fluorine-based material, and a porous ceramic-based material.

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

21. The battery cell according to claim 1, wherein: The lead film covering the upper surface of the recessed portion has a thickness of 100 μm to 300 μm.

22. A battery module comprising the battery cell according to claim 1.

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