Battery cell and battery module including the battery cell

Abstract

A battery cell according to one embodiment of the present invention includes: a battery case in which an electrode assembly is installed in a storage portion, the battery case including a sealing portion having a peripheral edge sealed by heat welding; 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 on at least one of an upper portion and a lower portion of the electrode lead, wherein a surface deformation portion is formed on an outer surface of the electrode lead and located between the lead film and the electrode lead.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2021-0030398 filed in Korea on March 8, 2021, the disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a battery cell and a battery module including the same, and more particularly, to a battery cell having improved external exhaust of gas generated inside the battery cell while ensuring easy manufacturing, and a battery module including the same. Background Art

[0003] As technology develops and demand for mobile devices increases, demand for secondary batteries as energy sources is rapidly increasing. In particular, secondary batteries are attracting attention as energy sources not only for mobile devices such as mobile phones, digital cameras, notebooks, and wearable devices, but also for power equipment 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 prismatic batteries in which the battery assembly is included in a cylindrical metal can or a prismatic metal can and a pouch-type battery in which the battery assembly is included in a pouch-type case of an aluminum laminate. Here, the battery assembly included in the battery case is an electric element that includes a positive electrode, a negative electrode, and a separator 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 and a separator is inserted between the positive electrode and the negative electrode, and 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 them, a pouch-type battery including a stacked or stacked / folded type battery assembly in a pouch-type battery case made of an aluminum laminate sheet is being increasingly used due to low manufacturing cost, light weight, and easy modification.

[0006] 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 a-a'. Figure 1 and Figure 2 A 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 thereof. 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.

[0007] However, in recent years, as the energy density of battery cells has increased, there has been a problem that the amount of gas generated inside the battery cells has also increased. In the case of a 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 the generation of gas. In addition, moisture may penetrate into the battery cell damaged by the degassing, which may cause a side reaction, and there is a problem that the battery performance deteriorates and additional gas is generated. Therefore, there is a growing need to develop a battery cell with improved external 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 having improved external exhaust of a gas generated inside the battery cell while ensuring easy manufacturing, and a battery module including the battery cell.

[0010] The objects solved by the present disclosure are not limited to the above-mentioned objects, and objects not mentioned here can be clearly understood by those skilled in the art based on this 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 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 case; an electrode lead electrically connected to an electrode connector included in the electrode assembly and protruding out of the battery case via the sealing portion; and a lead film located at a portion of at least one of an upper portion and a lower portion of the electrode lead corresponding to the sealing portion, wherein a surface deformation portion is formed on an outer surface of the electrode lead, and the surface deformation portion is located between the lead film and the electrode lead.

[0013] The surface deformation portion may be formed by removing a portion of the outer surface of the electrode lead.

[0014] A coating may be formed on an outer surface of the electrode lead, and the surface deformation portion may be formed by removing a portion of the coating.

[0015] The surface deformation can be formed by removing the coating by laser etching.

[0016] The coating may be made of a metallic material.

[0017] The metal material may include at least one of chromium and nickel.

[0018] The surface deformation portion may be configured to extend along a protruding direction of the electrode lead, and an end portion of the surface deformation portion disposed adjacent to the outer side of the sealing portion may be positioned further inward than an end portion of the lead film based on the protruding direction of the electrode lead.

[0019] The surface deformation portion may be configured to extend along a protruding direction of the electrode lead, and an end portion of the surface deformation portion disposed adjacent to the inner side of the sealing portion may be positioned further inward than an end portion of the lead film based on the protruding direction of the electrode lead.

[0020] The surface deformation portion may be configured to extend along a protruding direction of the electrode lead, and an end of the surface deformation portion disposed adjacent to the outer side of the sealing portion may be positioned further outward than an end of the lead film based on the protruding direction of the electrode lead.

[0021] The surface deformation portion may be configured to extend along a protruding direction of the electrode lead, and an end portion of the surface deformation portion disposed adjacent to the inner side of the sealing portion may be positioned outwardly than an end portion of the lead film based on the protruding direction of the electrode lead.

[0022] The surface deformation portion may be configured to extend in a direction perpendicular to a protruding direction of the electrode lead, and a length of the surface deformation portion may be smaller than a width of the electrode lead.

[0023] The surface deformation portion may have a circular shape or a rectangular shape.

[0024] One end of the surface deformed portion may be positioned further inward than the inner surface of the sealing portion based on the protruding direction of the electrode lead.

[0025] The other end of the surface deformed portion may be positioned further outward than the outer surface of the sealing portion based on the protruding direction of the electrode lead.

[0026] An area of ​​the other end of the surface deformation portion exposed to the outside of the outer surface of the sealing portion may be larger than an area of ​​the one end of the surface deformation portion exposed to the inside of the inner surface of the sealing portion.

[0027] The surface deformation portion may include a first surface deformation portion and a second surface deformation portion connected to each other, the first surface deformation portion may be configured to extend along a longitudinal direction of the sealing portion, and the second surface deformation portion may be configured to extend along a protruding direction of the electrode lead.

[0028] The length of the first surface deformed portion may be smaller than the width of the electrode lead.

[0029] The first surface deformation may be adjacent to an interior of the battery housing and the second surface deformation may be adjacent to an exterior of the battery housing.

[0030] The first surface deformation may be adjacent to the exterior of the battery housing and the second surface deformation may be adjacent to the interior of the battery housing.

[0031] The first surface-deformed portion may be completely located on the lead film, and one end of the second surface-deformed portion may not be covered by the lead film.

[0032] 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.

[0033] 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 integrated with each other.

[0034] The surface deformation portion may be located on at least one of an upper surface of the electrode lead and a lower surface of the electrode lead.

[0035] The lead film may have a gas permeability of 20 bar to 60 bar at 60°C.

[0036] The lead film may have a moisture permeation amount of 0.02 g to 0.2 g at 25° C., 50% RH for 10 years.

[0037] The lead film may comprise polypropylene.

[0038] The lead film on the surface deformed portion may have a thickness of 100 μm to 300 μm.

[0039] A width between the other end of the surface deformed portion and the outermost end of the lead film may be 2 mm or more.

[0040] In another aspect of the present disclosure, a battery module including the above-mentioned battery cell is also provided.

[0041] Beneficial Effects

[0042] According to an embodiment, the present disclosure provides a battery cell including an electrode lead having a surface deformation portion, thereby improving external discharge of gas generated inside the battery cell while ensuring ease of manufacturing, and a battery module including the battery cell.

[0043] 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 based on the present specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a top view showing a conventional battery cell.

[0045] Figure 2 is along Figure 1A cross-sectional view taken along the axis a-a'.

[0046] Figure 3 is a plan view showing a battery cell according to the present embodiment.

[0047] Figure 4 It is shown that the Figure 3 A three-dimensional view of the electrode leads in a battery cell.

[0048] Figure 5 is along Figure 4 A cross-sectional view taken along the axis c-c'.

[0049] Figure 6 is along Figure 4 A cross-sectional view taken along the axis d-d'.

[0050] Figure 7 It is shown Figure 3 A magnified view of the electrode leads and lead films in a battery cell.

[0051] Figure 8 is along Figure 3 A cross-sectional view taken along the axis b-b'.

[0052] Fig. 9 It is shown Figure 3 FIG. 1 is a diagram of an electrode lead whose surface is processed. DETAILED DESCRIPTION

[0053] 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.

[0054] 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.

[0055] 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 various layers and regions in the drawings, the thickness is exaggerated. In addition, in the drawings, for the convenience of explanation, the thickness of some layers and regions is exaggerated.

[0056] Furthermore, throughout the specification, when a part “includes” a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

[0057] In addition, throughout the specification, when a “top view” is mentioned, it means viewing a target portion from above, and when a “cross-sectional view” is mentioned, it means viewing a vertically cut portion of the target portion from one side.

[0058] Hereinafter, a pouch 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 the two side surfaces of the pouch type battery cell 100, but is not necessarily limited thereto, and the same or similar content may be described with the other side surface.

[0059] Figure 3 is a plan view showing a battery cell according to the present embodiment.

[0060] Reference Figure 3 , the battery cell 100 according to the present embodiment includes a battery case 200 , an electrode lead 300 , and a lead film 400 .

[0061] The battery case 200 includes a receiving portion 210 and a sealing portion 250, in which the electrode assembly 110 is installed, and the sealing portion 250 is formed by sealing the periphery of the battery case. The sealing portion 250 can be sealed by heat, laser, etc. The battery case 200 can be a laminate including a resin layer and a metal layer. More specifically, the battery case 200 can be made of a laminate, and can include an outer resin layer forming the outermost layer, a barrier metal layer to prevent material penetration, and an inner resin layer for sealing.

[0062] In addition, the electrode assembly 110 may have a jelly roll 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.

[0063] Hereinafter, the electrode lead 300 and the lead film 400 are mainly described.

[0064] Figure 4 It is shown that the Figure 3 A three-dimensional view of the electrode leads in a battery cell.

[0065] Reference Figure 3 and Figure 4 , the electrode lead 300 is electrically connected to an electrode tap (not shown) included in the electrode assembly 110, and the electrode lead 300 protrudes outside 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 performance of the sealing portion 250 and the electrode lead 300 while preventing a short circuit from occurring in the electrode lead 300 during sealing.

[0066] Figure 5 is along Figure 4 A cross-sectional view taken along the axis c-c'. Figure 6 is along Figure 4 Cross-sectional view taken along line d-d'.

[0067] Reference Figure 5 and Figure 6 , in the electrode lead 300, the surface deformation portion 350 is formed on the outer surface of the electrode lead 300, and the surface deformation portion 350 is located between the lead film 400 and the electrode lead 300. In the surface deformation portion 350, the adhesion between the electrode lead 300 and the lead film 400 is weak, or there is no adhesion at all. More specifically, in the electrode lead 300, the surface deformation portion 350 may be formed at a position corresponding to the lead film 400.

[0068] The surface deformation portion 350 may be formed by removing a portion of the outer surface of the electrode lead 300. Figure 5 and Figure 6 , the thickness of the surface deformed portion 350 is exaggerated to some extent, and in fact, the surface deformed portion 350 may be formed to a thickness at which the deformation is substantially not visually observed in the appearance of the electrode lead 300 .

[0069] For example, the surface deformation portion 350 may have a thickness of 0.01 μm to several hundred μm. However, the thickness of the surface deformation portion 350 is not limited thereto, and any thickness is applicable as long as it can weaken adhesion without damaging the airtightness and durability between the electrode lead 300 and the lead film 400.

[0070] In this embodiment, since the electrode lead 300 and the lead film 400 are partially spaced apart from each other by the surface deformation portion 350 , the surface deformation portion 350 may weaken adhesion of a portion between the electrode lead 300 and the lead film 400 .

[0071] In this way, the surface deformation portion 350 can weaken at least part of the adhesion between the lead film 400 and the electrode lead 300, and the portion where the adhesion is weakened by the surface deformation portion 350 (hereinafter referred to as the weak adhesion portion) can be used as a gas exhaust channel, through which the gas inside the battery housing 200 can be discharged to the outside.

[0072] More specifically, the pressure inside the battery cell 100 is higher than the pressure inside the weakly adhered portion, and the resulting pressure difference can act as a driving force for the gas. At this time, the portion of the weakly adhered portion located between the electrode lead 300 and the lead film 400 has relatively weak adhesion, so that due to the above-mentioned pressure difference, the gas generated inside the battery cell 100 can be introduced into the weakly adhered portion. Moreover, since the weakly adhered portion can have a pressure difference with the outside due to the gas introduced from the inside of the battery cell 100, the gas introduced into the weakly adhered portion can be discharged to the outside of the battery case 200.

[0073] Therefore, in the battery cell 100 according to the present embodiment, the gas generated inside the battery case 200 can be discharged to the weakly adhered portion according to the pressure difference with the inside of the weakly adhered portion, and the gas introduced into the weakly adhered portion can be discharged toward the outside according to the pressure difference with the outside.

[0074] In addition, according to an embodiment of the present disclosure, the position and shape of the weakly adhered portion formed between the lead film 400 and the electrode lead 300 can be controlled by the thickness, position, shape, etc. of the surface deformation portion 350. Therefore, the surface deformation portion 350 can appropriately adjust the degree of gas discharge inside the bag according to the airtightness and durability of the weakly adhered portion and the bag.

[0075] For example, a coating (not shown) may be formed on the outer surface of the electrode lead 300. Here, the coating (not shown) may be a layer formed by coating the outer surface of the electrode lead 300. Here, the surface deformation portion 350 may be formed by removing part of the coating (not shown). For ease of description, the coating (not shown) is not shown in the drawings, and the outer surfaces of the electrode lead 300 located on both sides of the surface deformation portion 350 may be described as the coating (not shown).

[0076] Generally, since it is not easy to combine the electrode lead 300 and the lead film 400 with each other, a coating layer for adhesion with the lead film 400 may be formed on the outer surface of the electrode lead 300 .

[0077] As in the embodiment of the present disclosure, if the surface deformation portion 350 is formed by removing a portion of the coating formed on the outer surface of the electrode lead 300, the adhesion between the electrode lead 300 and the lead film 400 may be weakened, or there may be no adhesion at all, in the surface deformation portion 350. Therefore, the gas generated inside the battery case 200 may be discharged to the surface deformation portion 350 at the interface between the electrode lead 300 and the lead film 400, and discharged to the outside of the battery case 200.

[0078] More specifically, the surface deformation portion 350 may be formed by etching a coating layer (not shown) by laser, UV-ozone (UvO) treatment, sputtering, etc. However, the etching method for the surface deformation portion 350 is not limited thereto, and any process capable of forming a predetermined shape by processing the surface of the electrode lead 300 may be applied.

[0079] For example, the coating (not shown) may be made of a metal material. More specifically, the metal material may include at least one of chromium and nickel. However, the coating (not shown) is not limited thereto, and may include a material that is generally coated on the outer surface of the electrode lead 300.

[0080] Therefore, since the surface deformation portion 350 can be formed by removing the coating (not shown) formed on the outer surface of the electrode lead 300, there is an advantage that the surface deformation portion 350 can be prepared by a relatively simple manufacturing process without requiring additional components. In addition, if the surface deformation portion 350 is formed by removing the coating (not shown) formed on the outer surface of the electrode lead 300, when the surface deformation portion 350 is actually observed with the naked eye, the deformation of the appearance of the electrode lead 300 can be minimized.

[0081] As another example, the surface deformation portion 350 may be formed by removing a portion itself corresponding to the outer surface of the electrode lead 300. That is, due to the surface deformation portion 350, the outer surface of the electrode lead 300 may have a step structure.

[0082] More specifically, the surface deformation portion 350 may be formed by etching the outer surface of the electrode lead 300 by laser, UV-ozone (UvO) treatment, sputtering, etc. However, the etching method for the surface deformation portion 350 is not limited thereto, and any process capable of forming a predetermined shape by processing the surface of the electrode lead 300 may be applied.

[0083] Therefore, since the surface deformation portion 350 may be formed by removing the outer surface of the electrode lead 300 , the surface deformation portion 350 may be prepared through a relatively simple manufacturing process, and there is an advantage that no additional components are required.

[0084] For example, refer to Figure 5 and Figure 6 , the lead film 400 may include a first lead film and a second lead film respectively located at the upper and lower portions of the electrode lead 300. In addition, the first lead film and the second lead film may be integrated with each other. Therefore, the lead film 400 may improve the sealing properties of the sealing portion 250 and the electrode lead 300 while preventing the side surface of the electrode lead 300 from being exposed to the outside.

[0085] Here, the surface deformation portion 350 may be located on at least one of the upper surface of the electrode lead 300 and the lower surface of the electrode lead 300. Figure 5 (a) and Figure 6 In (a), when the surface deformation portion 350 is located on the upper surface of the electrode lead 300, the surface deformation portion 350 may be covered by the first lead film of the lead film 400. Conversely, when the surface deformation portion 350 is located on the lower surface of the electrode lead 300, this may also be the same. Figure 5 (b) and Figure 6As shown in (b), when the surface deformation portions 350 are respectively located on the upper surface and the lower surface of the electrode lead 300, the surface deformation portions 350 can be covered by the first lead film and the second lead film, respectively. However, the number of the surface deformation portions 350 is not limited to the above, and the surface deformation portions 350 can be formed on the outer surface of the electrode lead 300 in an appropriate number.

[0086] Therefore, by adjusting the number of surface deformation portions 350 formed on the outer surface of the electrode lead 300, the durability and airtightness between the electrode lead 300 and the lead film 400 can be controlled. In addition, by minimizing the number of surface deformation portions 350 as needed, the manufacturing process can be simplified and the cost can be reduced.

[0087] Figure 7 It is shown Figure 3 A magnified view of the electrode leads and lead films in a battery cell.

[0088] Reference Figures 5 to 7 , based on the protruding direction of the electrode lead 300, the surface deformation portion 350 extends along the protruding direction of the electrode lead 300, and the end of the surface deformation portion 350 adjacent to the outside of the sealing portion 250 can be positioned more inward than the end of the lead film. Here, the end of the surface deformation portion 350 that is positioned more inward than the end of the lead film means that the end of the surface deformation portion 350 is covered by the lead film. That is, this means that the end of the surface deformation portion 350 adjacent to the outside of the sealing portion 250 is positioned in the internal direction of the battery case 200 (rather than the end of the lead film). In this specification, the outside of the sealing portion 250 refers to the end of the sealing portion 250 adjacent to the outside of the battery case 200.

[0089] In addition, based on the protruding direction of the electrode lead 300, the end of the surface deformation portion 350 adjacent to the inner side of the sealing portion 250 can be positioned more inward than the end of the lead film. Here, the end of the surface deformation portion 350 positioned more inward than the end of the lead film means that the end of the surface deformation portion 350 is covered by the lead film. In other words, this means that the end of the surface deformation portion 350 adjacent to the inner side of the sealing portion 250 is positioned in the outer direction of the battery housing 200 (rather than the end of the lead film). In this specification, the inner side of the sealing portion 250 refers to the end of the sealing portion 250 adjacent to the inner side of the battery housing 200.

[0090] In addition, based on the protruding direction of the electrode lead 300, the end of the surface deformation portion 350 adjacent to the outside of the sealing portion 250 can be positioned to be more outside than the end of the lead film. Here, the surface deformation portion 350 is positioned to be more outside than the end of the lead film, which means that the end of the surface deformation portion 350 is not covered by the lead film. In other words, this means that the end of the surface deformation portion 350 adjacent to the outside of the sealing portion 250 is positioned in the external direction of the battery housing 200 (rather than the end of the lead film). In this specification, the outside of the sealing portion 250 refers to the end of the sealing portion 250 adjacent to the outside of the battery housing 200.

[0091] In addition, based on the protruding direction of the electrode lead 300, the end of the surface deformation portion 350 adjacent to the inner side of the sealing portion 250 can be positioned to be more outward than the end of the lead film. Here, the end of the surface deformation portion 350 positioned to be more outward than the end of the lead film means that the end of the surface deformation portion 350 is not covered by the lead film. In other words, this means that the end of the surface deformation portion 350 adjacent to the inner side of the sealing portion 250 is positioned in the internal direction of the battery housing 200 (rather than the end of the lead film). In this specification, the inner side of the sealing portion 250 refers to the end of the sealing portion 250 adjacent to the inner side of the battery housing 200.

[0092] In one embodiment, the surface deformation portion 350 may be positioned between one end and the other end of the lead film 400 based on the protruding direction of the electrode lead 300 .

[0093] In addition, the surface deformation portion 350 extends in a direction perpendicular to the protruding direction of the electrode lead 300, and the length of the surface deformation portion 350 may be smaller than the width of the electrode lead 300. In the present specification, the length of the surface deformation portion 350 refers to the maximum value of the distance between one end and the other end of the surface deformation portion 350 based on the direction perpendicular 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 based on the direction perpendicular to the protruding direction of the electrode lead 300.

[0094] For example, refer to Figure 7 (a) and Figure 7 (b), the surface deformation portion 350 may have a circular shape or a rectangular shape. When the surface deformation portion 350 has a circular shape or a rectangular shape, the surface deformation portion 350 may have a large area.

[0095] Therefore, if Figure 7 (a) and Figure 7As shown in (b), even if both one end and the other end of the surface deformation portion 350 are located between one end and the other end of the lead film 400 based on the protruding direction of the electrode lead 300, gas can be easily discharged.

[0096] Although in Figure 7 (a) and Figure 7 Although not shown in (b), when the surface deformation portion 350 has a circular or rectangular shape, one end and / or the other end of the surface deformation portion 350 based on the protruding direction of the electrode lead 300 may not be covered by the lead film 400. In this case, compared with a case where both one end and the other end of the surface deformation portion 350 are located between one end and the other end of the lead film 400, gas can be discharged more easily.

[0097] As another example, refer to Figure 7 (c) and Figure 7 (d), the surface deformation portion 350 includes a first surface deformation portion 350a and a second surface deformation portion 350b connected to each other, wherein the first surface deformation portion 350a may extend along the longitudinal direction of the sealing portion, and the second surface deformation portion 350b may extend along the protruding direction of the electrode lead 300. In this specification, the longitudinal direction of the sealing portion refers to a direction perpendicular to the protruding direction of the electrode lead 300.

[0098] Here, reference Figure 3 and Figure 7 (c), the first surface deformation portion 350a may be positioned adjacent to the inside of the battery case 200. That is, the first surface deformation portion 350a may be positioned adjacent to the inner side of the sealing portion 250 based on the protruding direction of the electrode lead 300.

[0099] In addition, refer to Figure 3 and Figure 7 (c), the second surface deformation portion 350b may be positioned adjacent to the outside of the battery case 200. That is, the second surface deformation portion 350b may be positioned adjacent to the outside of the sealing portion 250 based on the protruding direction of the electrode lead 300.

[0100] For example, the length of the first surface deformation portion 350 a may be smaller than the width of the electrode lead 300 .

[0101] In the present specification, the length of the first surface deformation portion 350a refers to the maximum value of the distance between one end and the other end of the first surface deformation portion 350a based on a direction perpendicular to the protruding direction of the electrode lead 300, and the width of the electrode lead 300 may refer to the maximum value of the distance between one end and the other end of the electrode lead 300 based on a direction perpendicular to the protruding direction of the electrode lead 300.

[0102] Reference Figure 7 (c) and Figure 7 (d), the first surface deformation portion 350 a may be completely positioned on the lead film 400 .

[0103] Reference Figure 3 and Figure 7 (c), since one end of the second surface deformation portion 350b extends toward the outside of the battery case 200, the one end of the second surface deformation portion 350b may not be covered by the lead film 400. Therefore, since one end of the second surface deformation portion 350b is exposed to the outside of the battery case 200, the amount of gas discharged by the surface deformation portion 350 can be more effectively increased.

[0104] In addition, reference Figure 3 and Figure 7 (d), the first surface deformation portion 350a may be positioned adjacent to the outside of the battery case 200. That is, the first surface deformation portion 350a may be positioned adjacent to the outside of the sealing portion 250 based on the protruding direction of the electrode lead 300.

[0105] In addition, refer to Figure 3 and Figure 7 (d), the second surface deformation portion 350b may be positioned adjacent to the inside of the battery case 200. That is, the second surface deformation portion 350b may be positioned adjacent to the inner side of the sealing portion 250 based on the protruding direction of the electrode lead 300.

[0106] More specifically, if Figure 7 As shown in (d), since one end of the second surface deformation portion 350b extends toward the inside of the battery case 200, the one end of the second surface deformation portion 350b may not be covered by the lead film 400. Therefore, since one end of the second surface deformation portion 350b is exposed to the inside of the battery case 200, the amount of gas discharged by the surface deformation portion 350 can be more effectively increased.

[0107] However, the shape of the surface deformation portion 350 is not limited to the above, and the surface deformation portion 350 may be formed in an appropriate shape on the outer surface of the electrode lead 300 .

[0108] Therefore, by controlling the shape of the surface deformation portion 350 formed on the outer surface of the electrode lead 300, the durability and airtightness or gas discharge amount between the electrode lead 300 and the lead film 400 can be controlled. In addition, by changing the shape of the surface deformation portion 350 as needed, the manufacturing process can be simplified and the cost can be reduced.

[0109] Figure 8 is along Figure 3 A cross-sectional view taken along the axis b-b'.

[0110] Reference Figure 8 , based on the protruding direction of the electrode lead 300, one end of the surface deformation portion 350 may be positioned more inward than the inner surface of the sealing portion 250. In the present specification, the inner surface of the sealing portion 250 means the end of the sealing portion 250 adjacent to the inside of the battery case 200, and the one end of the surface deformation portion 350 positioned more inward than the inner surface of the sealing portion 250 means that the one end of the surface deformation portion 350 is located in the inner direction of the battery case 200 (not the inner surface of the sealing portion 250). If one end of the surface deformation portion 350 is positioned more inward than the inner surface of the sealing portion 250, the surface deformation portion 350 is not disturbed by the sealing portion 250, so that the gas can be more easily introduced into the surface deformation portion 350.

[0111] In addition, based on the protruding direction of the electrode lead 300, the other end of the surface deformation portion 350 can be positioned further outward than the outer surface of the sealing portion 250. In this specification, the outer surface of the sealing portion 250 refers to the end of the sealing portion 250 adjacent to the outside of the battery case 200, and the other end of the surface deformation portion 350 positioned further outward than the outer surface of the sealing portion 250 means that the other end of the surface deformation portion 350 is located in the outer direction of the battery case 200 (rather than the outer surface of the sealing portion 250). If the other end of the surface deformation portion 350 is positioned further outward than the outer surface of the sealing portion 250, the gas introduced into the surface deformation portion 350 can be more easily discharged to the outside. For example, since the other end of the surface deformation portion 350 is not disturbed by the sealing portion 250, the gas introduced into the surface deformation portion 350 can be more easily discharged to the outside.

[0112] Therefore, the gas generated inside the battery cell 100 can be discharged toward the surface deformation portion 350, and the gas introduced into the surface deformation portion 350 can be easily discharged toward the outside. If both ends of the surface deformation portion 350 formed on the outer surface of the electrode lead 300 are exposed to the inside of the battery case 200 and the outside of the battery case 200, the gas generated inside the battery case 200 is easily introduced into the surface deformation portion 350 and can be more easily discharged to the outside of the surface deformation portion 350.

[0113] Specifically, the gas introduced into the surface deformation portion 350 can be discharged along the Z-axis direction via the lead film 400 on the surface deformation portion 350. For example, if the other end of the surface deformation portion 350 is positioned more outward than the outer surface of the sealing portion 250 and is positioned more inward than the end of the lead film 400 (in the inner direction of the battery housing 200), the gas introduced into the surface deformation portion 350 can be discharged along the Z-axis direction from the lead film 400 between the other end of the surface deformation portion 350 and the outer surface of the sealing portion 250. Alternatively, although not in Figure 8 As shown in the figure, however, if the other end of the surface deformation portion 350 is positioned further outward than the outer surface of the sealing portion 250 and is positioned further outward than the end of the lead film 400 (in the external direction of the battery housing 200), the gas introduced into the surface deformation portion 350 can be immediately discharged to the outside.

[0114] In one embodiment of the present disclosure, at 60° C., the gas permeability of the lead film 400 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 lead film 400 having a thickness 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 battery cell can be discharged more effectively.

[0115] In this specification, the gas permeability may be measured by ASTM F 2476-20.

[0116] In one embodiment of the present disclosure, 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 at 25° C. and 50% RH. 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.

[0117] The moisture permeation amount of the lead film 400 may be measured by adopting the ASTM F 1249 method. At this time, the moisture permeation amount may be measured using an apparatus officially certified by MCOON.

[0118] In one embodiment of the present disclosure, the lead film 400 may have a gas permeability of 20 bar to 60 bar at 60° C. and a moisture permeation amount of 0.02 g to 0.2 g at 50% RH at 25° C. for 10 years. If the gas permeability and moisture permeation amount of the lead film 400 satisfy the above ranges, while exhausting the gas generated inside the secondary battery, moisture can be more effectively prevented from penetrating from the outside.

[0119] In one embodiment of the present disclosure, the lead film 400 may include a polyolefin resin. For example, the lead film 400 may include a polyolefin resin that satisfies the above-mentioned gas permeability and / or moisture permeability values. The polyolefin resin may include at least one material selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). Although the lead film 400 includes polypropylene, the gas permeability of the lead film 400 may be 20 bar to 60 bar at 60°C. In addition, the moisture permeability may be between 0.06 and 0.15 grams. In this case, the gas generated inside the secondary battery can be discharged more effectively, and moisture can be easily prevented from penetrating from the outside.

[0120] In addition, since the lead film 400 is made of the above-mentioned material, the lead film 400 may maintain the airtightness of the battery cell 100 and prevent leakage of an internal electrolyte solution.

[0121] Reference Figure 8 , the thickness (H) of the lead film 400 located on the surface deformation portion 350 may be 100 μm to 300 μm, or 100 μm to 200 μm. If the thickness (H) of the lead film 400 located on the surface deformation portion 350 satisfies the above range, the gas inside the battery case 200 can be more easily discharged to the outside.

[0122] Reference Figure 8 , if the other end of the surface deformation portion 350 is positioned outside the outer surface of the sealing portion 250 and is positioned inside the end of the lead film 400 (in the inner direction of the battery case 200), the width (W) between the other end of the surface deformation portion 350 and the outermost end of the lead film 400 may be 2 mm or more, or 2 mm to 3 mm. If the width (W) between the other end of the surface deformation portion 350 and the outermost end of the lead film 400 satisfies the above range, it is easier to prevent the lead film 400 from being torn during the process of discharging the gas generated inside the battery case 200 to the outside.

[0123] In one embodiment of the present disclosure, if one end of the surface deformation portion 350 is positioned more inward than the inner surface of the sealing portion 250, and the other end of the surface deformation portion 350 is positioned more outward than the outer surface of the sealing portion 250, the area of ​​the other end of the surface deformation portion 350 exposed to the outside of the outer surface of the sealing portion 250 may be greater than the area of ​​the one end of the surface deformation portion 350 exposed to the inside of the inner surface of the sealing portion 250. The gas discharge amount is proportional to the gas discharge area and the pressure. Since the pressure on the inside of the battery case 200 is greater than the pressure on the outside of the battery case 200, if the area of ​​the other end of the surface deformation portion 350 exposed to the outside of the outer surface of the sealing portion 250 is greater than the area of ​​the one end of the surface deformation portion 350 exposed to the inside of the inner surface of the sealing portion 250, the gas generated inside the battery case 200 can be more easily discharged to the outside.

[0124] In one embodiment of the present disclosure, the area of ​​the other end of the surface deformation portion 350 exposed at the outside of the sealing portion 250 may be 40 mm 2 Up to 80mm 2 This is a size that about 0.5cc to 3cc of gas can be discharged per day based on an internal pressure of 1atm at 60°C. In addition, this is a size that the amount of moisture permeation can be 0.02g to 0.2g in 10 years at 25°C and 50%RH.

[0125] although Figure 8 400, but one end and / or the other end of the surface deformation portion 350 may not be covered by the lead film 400. That is, one end of the surface deformation portion 350 may be exposed to the inside of the battery housing 200. In this case, when the gas inside the battery housing 200 is introduced into the surface deformation portion 350, one end of the surface deformation portion 350 is not disturbed by the sealing portion 250 and the lead film 400, so that the gas can be introduced more easily. Moreover, the other end of the surface deformation portion 350 may be exposed to the outside of the battery housing 200. In this case, the gas can be discharged to the outside more easily.

[0126] Fig. 9 It is shown Figure 3 FIG. 1 is a diagram of an electrode lead whose surface is processed.

[0127] Reference Fig. 9, a battery cell manufacturing apparatus 1000 according to another embodiment of the present disclosure may emit a laser to an electrode lead 300 to form a surface deformation portion 350 on an outer surface of the electrode lead 300. More specifically, the battery cell manufacturing apparatus 1000 may etch the outer surface of the electrode lead 300 using a laser to form a surface deformation portion 350 on the outer surface of the electrode lead 300. Here, before assembling each component of the battery cell 100, a process of forming the surface deformation portion 350 by the battery cell manufacturing apparatus 1000 may be performed in advance. However, the method of manufacturing the surface deformation portion 350 is not limited thereto, and any process capable of removing a portion of the outer surface of the electrode lead 300 is applicable.

[0128] Therefore, the battery cell manufacturing apparatus 1000 according to this embodiment can easily form the surface deformation portion 350 having a predetermined shape and size on the outer surface of the electrode lead 300 .

[0129] For example, when the surface deformed portion 350 is formed by removing a portion of the outer surface of the electrode lead 300, the intensity of the laser emitted from the battery cell manufacturing apparatus 1000 may be sufficient to damage the outer surface of the electrode lead 300. As another example, when the surface deformed portion 350 is formed by removing a portion of a coating (not shown) formed on the outer surface of the electrode lead 300, the intensity of the laser emitted from the battery cell manufacturing apparatus 1000 may be sufficient to damage the coating (not shown) formed on the outer surface of the electrode lead 300.

[0130] Therefore, the intensity of the laser applied to the outer surface of the electrode lead 300 may be adjusted so that the surface deformation portion 350 may be appropriately formed according to the configuration of the outer surface of the electrode lead 300 .

[0131] A battery module according to another embodiment of the present disclosure includes the above-mentioned battery cell. In addition, one or more battery modules according to this embodiment may be packaged in a battery pack case to form a battery pack.

[0132] 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.

[0133] 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.

Claims

1. A battery cell, comprising: a battery case having a receiving portion in which an electrode assembly is mounted and a sealing portion formed by 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 which protrudes outside 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 surface deformation portion is formed on the outer surface of the electrode lead, and The surface deformation portion is located between the lead film and the electrode lead, Wherein, based on the protruding direction of the electrode lead, one end of the surface deformed portion is positioned more inward than the inner surface of the sealing portion, and the other end of the surface deformed portion is positioned more outward than the outer surface of the sealing portion.

2. The battery cell according to claim 1, in, The surface deformation portion is formed by removing a portion of an outer surface of the electrode lead.

3. The battery cell according to claim 1, in, A coating is formed on the outer surface of the electrode lead, and The surface deformation portion is formed by removing a portion of the coating layer.

4. The battery cell according to claim 3, in, The surface deformation portion is formed by removing the coating layer using laser etching.

5. The battery cell according to claim 3, in, The coating is made of metal material.

6. The battery cell according to claim 5, in, The metal material includes at least one of chromium and nickel.

7. The battery cell according to claim 1, in, The surface deformation portion is configured to extend along a protruding direction of the electrode lead, and An end portion of the surface deformed portion disposed adjacent to an outer side of the sealing portion is positioned more inner than an end portion of the lead film based on a protruding direction of the electrode lead.

8. The battery cell according to claim 1, in, The surface deformation portion is configured to extend along a protruding direction of the electrode lead, and An end portion of the surface deformed portion disposed adjacent to an inner side of the sealing portion is positioned more inner than an end portion of the lead film based on a protruding direction of the electrode lead.

9. The battery cell according to claim 1, in, The surface deformation portion is configured to extend along a protruding direction of the electrode lead, and An end portion of the surface deformed portion disposed adjacent to an outer side of the sealing portion is positioned more outward than an end portion of the lead film based on a protruding direction of the electrode lead.

10. The battery cell according to claim 1, in, The surface deformation portion is configured to extend along a protruding direction of the electrode lead, and An end portion of the surface deformed portion disposed adjacent to an inner side of the sealing portion is positioned more outward than an end portion of the lead film based on a protruding direction of the electrode lead.

11. The battery cell according to claim 1, wherein: The surface deformed portion is positioned between one end and the other end of the lead film based on a protruding direction of the electrode lead.

12. The battery cell according to claim 1, in, The surface deformation portion is configured to extend in a direction perpendicular to a protruding direction of the electrode lead, and a length of the surface deformation portion is smaller than a width of the electrode lead.

13. The battery cell according to claim 1, in, The surface deformation portion has a circular shape or a rectangular shape.

14. The battery cell according to claim 1, in, An area of ​​the other end of the surface deformation portion exposed to the outside of the outer surface of the sealing portion is larger than an area of ​​one end of the surface deformation portion exposed to the inside of the inner surface of the sealing portion.

15. The battery cell according to claim 1, in, The surface deformation portion includes a first surface deformation portion and a second surface deformation portion connected to each other, The first surface deformation portion is configured to extend along a longitudinal direction of the sealing portion, and The second surface deformation portion is configured to extend along a protruding direction of the electrode lead.

16. The battery cell according to claim 15, in, The length of the first surface deformation portion is smaller than the width of the electrode lead.

17. The battery cell according to claim 15, in, The first surface deformation is positioned adjacent to an interior of the battery housing, and The second surface deformation is located adjacent to an exterior of the battery housing.

18. The battery cell according to claim 15, in, The first surface deformation is positioned adjacent to an exterior of the battery housing, and The second surface deformation is positioned adjacent to an interior of the battery housing.

19. The battery cell according to claim 15, in, The first surface deformation portion is completely located on the lead film, and One end of the second surface deformation portion is not covered by the lead film.

20. 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 at an upper portion of the electrode lead, and the second lead film is located at a lower portion of the electrode lead.

21. The battery cell according to claim 20, 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 integrated with each other.

22. The battery cell according to claim 1, in, The surface deformation portion is located on at least one of an upper surface of the electrode lead and a lower surface of the electrode lead.

23. The battery cell according to claim 1, in, The lead film has a gas permeability of 20 bar to 60 bar 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 at 25° C., 50% RH within 10 years.

25. The battery cell according to claim 1, in, The lead film includes a polyolefin resin.

26. The battery cell according to claim 1, in, The lead film located on the surface deformed portion has a thickness of 100 μm to 300 μm.

27. The battery cell according to claim 1, in, A width between the other end of the surface deformed portion and the outermost end of the lead film is 2 mm or more.

28. A battery module comprising the battery cell according to any one of claims 1-27.

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