Battery cell and battery module including same

Abstract

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

Description

[Technical field]

[0001] The present invention relates to a battery cell and a battery module including the same, and more particularly to a battery cell with improved gas discharge performance and a battery module including the same. This application claims priority based on Korean Patent Application No. 10-2021-0088728 filed on July 6, 2021 and Korean Patent Application No. 10-2022-0081996 filed on July 4, 2022, and the contents disclosed in the specification and drawings of said applications are incorporated herein in their entirety. [Background technology]

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

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

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

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

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

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

[0008] An object of the present invention is to provide a battery cell having improved gas discharge performance and a battery module including the same.

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

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

[0011] A length of the first sealing portion may be longer than a length of the gas discharge guiding portion in a direction perpendicular to a protruding direction of the electrode lead.

[0012] The gas discharge guide portion may be located at the center of the first sealing portion.

[0013] The first sealing portion may have a pattern that is recessed with respect to the second sealing portion.

[0014] The first sealing portion may have a pattern that is recessed outward from the inside of the sealing portion.

[0015] A receiving extension may be located between the first sealing portion and the receiving portion.

[0016] With respect to the outside of the battery case, an end of the receiving extension portion may be located outside an end of the receiving portion.

[0017] The gas discharge guiding portion may extend along a protruding direction of the electrode lead, and an end of the gas discharge guiding portion adjacent to an outside of the battery case may be covered with the lead film.

[0018] An end of the gas discharge guide portion adjacent to the inside of the battery case may be exposed to the inside of the battery case.

[0019] A gas exhaust path may be formed at an interface between the gas exhaust guide portion and the lead film.

[0020] An adhesive strength between the gas exhaust guide portion and the lead film may be smaller than an adhesive strength between the lead film and an electrode lead or an adhesive strength between the lead film and the sealing portion.

[0021] The gas discharge guide portion may be a film layer made of at least one of polyimide and polyethylene terephthalate.

[0022] The gas discharge guide portion may be a coating layer made of a liquid resin.

[0023] The gas exhaust guide portion is made of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO 2 The substrate may further include a getter material including at least one of barium oxide (BaO), barium (Ba), and calcium (Ca).

[0024] The gas discharge guide may be located on the electrode lead, and an adhesive layer may be formed between the gas discharge guide and the electrode lead.

[0025] An adhesive strength between the gas discharge guide portion and the lead film may be smaller than an adhesive strength between the adhesive layer and the gas discharge guide portion and an adhesive strength between the adhesive layer and the electrode lead.

[0026] The adhesive layer may consist of an adhesive tape or an adhesive binder.

[0027] The gas permeability of the lead film may be 20 to 60 barrers at 60°C.

[0028] The lead film may have a moisture permeation amount of 0.02 g to 0.2 g over 10 years at 25° C. and 50% RH.

[0029] The gas discharge guide portion may have a gas permeability of 40 barrer or more at 60°C.

[0030] A battery module according to another aspect of the present invention includes the above-described battery cells. Effect of the Invention

[0031] According to an embodiment of the present invention, a battery cell and a battery module including the same in which the length of a sealing portion located on a gas exhaust guide portion is relatively short are provided, thereby improving gas exhaust performance.

[0032] Specifically, according to one embodiment of the present invention, a gas exhaust path can be formed at the interface between the gas exhaust guide portion and the lead film, making the manufacturing process relatively easy and allowing gas within the battery cell to be effectively exhausted to the outside.

[0033] According to another embodiment of the present invention, the sealing portion includes a first sealing portion and a second sealing portion, and the width of the first sealing portion is made different from the width of the second sealing portion, thereby reducing the sealing strength between the lead film and the sealing portion, and when the internal pressure increases, the lead film is easily peeled off from the gas exhaust guiding portion due to the internal pressure, and a gas exhaust path can be easily formed between the gas exhaust guiding portion and the lead film.

[0034] According to another embodiment of the present invention, a portion of the lead film that is not sealed by the first sealing part is formed, so that the portion comes into direct contact with the internal gas when the internal pressure increases, and therefore the lead film can be more easily peeled off from the gas exhaust guide part by the internal pressure.

[0035] According to another embodiment of the present invention, the gas discharge performance of the gas discharge guide portion, the durability and airtightness of the lead film can be controlled by adjusting the shape of the gas discharge guide portion. Also, the shape of the gas discharge guide portion can be changed as necessary to simplify the manufacturing process and reduce costs.

[0036] According to yet another embodiment of the present invention, by setting the gas permeability and moisture penetration amount of the lead film within a predetermined range, it is possible to more effectively prevent moisture penetration from the outside while still allowing gas generated inside the battery cell to be discharged.

[0037] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 is a top view of a conventional battery cell. [Diagram 2] FIG. 2 is a cross-sectional view taken along line a-a' in FIG. [Diagram 3] FIG. 2 is a top view of a battery cell according to one embodiment of the present invention. [Figure 4] 4(a) is an enlarged view of the area enclosed by the two-dot chain line in FIG. 3, and (b) is an enlarged view of the area enclosed by the two-dot chain line in FIG. 3 according to another embodiment of the present invention. [Diagram 5] 4(a) is a cross-sectional view taken along line AA' in FIG. 3. FIG. [Figure 6] 11A to 11C are diagrams showing various shapes of the gas discharge guide portion; [Figure 7] 6 is an enlarged view of the area enclosed by the two-dot chain line in FIG. 5. [Figure 8] 8 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 7. FIG. [Figure 9] 8 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 7. FIG. [Figure 10] FIG. 10 is a perspective view showing a gas exhaust path in FIG. 9. [Figure 11] 4 is a cross-sectional view taken along line AA' of FIG. 3, showing a battery cell according to another embodiment of the present invention. [Figure 12] 12 is an enlarged view of the area enclosed by the two-dot chain line in FIG. 11. [Figure 13] 13 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 12. FIG. [Figure 14] 13 is a diagram showing a gas discharge path formed at the interface between the lead film and the gas discharge guide portion in FIG. 12. FIG. [Figure 15] 2 is an enlarged view of a region enclosed by a two-dot chain line in FIG. 1 in a comparative example. [Figure 16] FIG. 2 is a cross-sectional view taken along line aa' in FIG. 1 in a comparative example. [Figure 17] FIG. 17 is an enlarged view of the area surrounded by the two-dot chain line in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0040] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0041] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not limited by the drawings. In the drawings, thicknesses are enlarged to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0042] Furthermore, throughout the specification, when a part is described as "comprising" a certain component, this does not mean that other components are excluded, but that other components may also be included, unless otherwise specified.

[0043] Furthermore, throughout the specification, a "plan view" means a view of the subject part viewed from above, and a "cross-sectional view" means a view of a vertical cross-section of the subject part viewed from the side.

[0044] Hereinafter, a battery cell according to an embodiment of the present invention will be described. However, the description will be made based on one end of the battery cell, but the present invention is not limited thereto, and the same or similar description may be applied to the other end of the battery cell.

[0045] FIG. 3 is a top view of a battery cell according to one embodiment of the present invention.

[0046] 3, the battery cell 100 according to the embodiment of the present invention includes a battery case 200 including a storage section 210 to which an electrode assembly 110 is attached and a sealing section 250 formed by sealing the outer periphery of the storage section 210, an electrode lead 300 electrically connected to an electrode tab 150 included in the electrode assembly 110 and protruding to the outside of the battery case 200 through the sealing section 250, and a lead film 400 located at a portion corresponding to the sealing section 250 at at least one of the upper and lower parts of the electrode lead 300. For example, the battery cell 100 may be a substantially rectangular plate-shaped cell by having a long side in the X-axis direction and a short side in the Y-axis direction, and being formed shorter in the Z-axis direction than the length of the X-axis or Y-axis. The electrode lead 300 may be formed on the short side of the battery cell 100. Such a battery cell 100 is an efficient structure for increasing energy density by integrating in the Z-axis direction and stacking a plurality of battery cells 100 face-to-face.

[0047] The battery case 200 may be made of a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 may be made of a laminate sheet and may be composed of an outer resin layer forming the outermost shell, a barrier metal layer that prevents the passage of substances, and an inner resin layer for sealing.

[0048] The electrode assembly 110 may have a jelly roll type (wound type), a laminate type (stack type), or a composite type (lamination / folding type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0049] The electrode lead 300 is electrically connected to the electrode tab 150 included in the electrode assembly 110, and protrudes to the outside of the battery case 200 through the sealing part 250. In addition, the lead film 400 is located at a portion corresponding to the sealing part 250 on at least one of the upper and lower parts of the electrode lead 300. Thus, the lead film 400, together with the sealing part 250, can prevent a short circuit from occurring in the electrode lead 300 during heat fusion or press fusion, and can improve the sealing property between the sealing part 250 and the electrode lead 300.

[0050] 3, the lead film 400 may have a width wider than that of the electrode lead 300. Here, the width of the lead film 400 means the maximum distance between one end and the other end of the lead film 400 in a direction (Y-axis direction) perpendicular to the protruding direction of the electrode lead 300 (X-axis direction), and the width of the electrode lead 300 means the maximum distance between one end and the other end of the electrode lead 300 in a direction perpendicular to the protruding direction of the electrode lead 300.

[0051] The lead film 400 may have a length longer than the sealing portion 250 and shorter than the electrode lead 300 based on the protruding direction of the electrode lead 300. Here, the length of the lead film 400 means the maximum value of the distance between one end and the other end of the lead film 400 in the protruding direction of the electrode lead 300. The length of the sealing portion 250 means the maximum value of the distance between one end and the other end of the sealing portion 250 in the protruding direction of the electrode lead 300. The length of the electrode lead 300 means the maximum value of the distance between one end and the other end of the electrode lead 300 in the protruding direction of the electrode lead 300. Thus, the lead film 400 does not interfere with the electrical connection of the electrode lead 300 and can prevent the side of the electrode lead 300 from being exposed to the outside.

[0052] FIG. 4(a) is an enlarged view of the area enclosed by the two-dot chain line in FIG. 3, and FIG. 4(b) is an enlarged view of the area enclosed by the two-dot chain line in FIG. 3 according to another embodiment of the present invention.

[0053] 3 and 4, a gas exhaust guiding portion 450 is inserted into a lead film 400, and the sealing portion 250 includes a first sealing portion 251 located on the gas exhaust guiding portion 450 and a second sealing portion 255 located on both sides of the first sealing portion 251. In other words, the second sealing portion 255 may be located in a portion where the gas exhaust guiding portion 450 is not located. More specifically, the first sealing portion 251 and the second sealing portion 255 may be integrated with each other.

[0054] 4, the width D1 of the first sealing portion 251 is narrower than the width D2 of the second sealing portion 255 based on the protruding direction of the electrode lead 300. Here, the width of the first sealing portion 251 means the maximum value of the distance between one end and the other end of the first sealing portion 251 in the protruding direction of the electrode lead 300. The width of the second sealing portion 255 means the maximum value of the distance between one end and the other end of the second sealing portion 255 in the protruding direction of the electrode lead 300. More specifically, the width D1 of the surface of the first sealing portion 251 that contacts the lead film 400 is narrower than the width D2 of the surface of the second sealing portion 255 that contacts the lead film 400. That is, based on the protruding direction of the electrode lead 300, at least a part of the portion of the lead film 400 where the gas discharge guiding portion 450 is located is not covered by the first sealing portion 251.

[0055] 4, the length L1 of the first sealing part 251 may be longer than the length L2 of the gas exhaust guiding part 450 based on the direction perpendicular to the protruding direction of the electrode lead 300. Here, the length of the first sealing part 251 means the maximum value of the distance between one end and the other end of the first sealing part 251 in the direction perpendicular to the protruding direction of the electrode lead 300. The length of the gas exhaust guiding part 450 means the maximum value of the distance between one end and the other end of the gas exhaust guiding part 450 in the direction perpendicular to the protruding direction of the electrode lead 300. In other words, based on the direction perpendicular to the protruding direction of the electrode lead 300, at least a part of the part of the lead film 400 where the gas exhaust guiding part 450 is located is not covered by the first sealing part 251. More specifically, the gas exhaust guiding part 450 may be located at the center of the first sealing part 251. However, the position of the gas discharge guide portion 450 is not limited thereto, and any position within the first sealing portion 251 is included in this embodiment.

[0056] Here, the length of the first sealing portion 251 can be adjusted according to the degree of gas discharge from the gas discharge path described below while maintaining the sealing performance of the battery cell 100.

[0057] As configured above, in the battery cell 100 according to the present embodiment, the width D1 of the first sealing portion 251 located on the gas discharge guiding portion 450 is formed relatively narrow with respect to the protruding direction of the electrode lead 300, so that at least a portion of the lead film 400 located on the gas discharge guiding portion 450 is not sealed by the first sealing portion 251. In other words, the portion of the lead film 400 that is not sealed by the first sealing portion 251 may be exposed.

[0058] In other words, the portion of the lead film 400 that is not sealed by the first sealing portion 251 has a lower sealing strength of the sealing portion 250, and when the internal pressure increases, the lead film 400 is easily peeled off from the gas exhaust guiding portion 450 due to the internal pressure, and a gas exhaust path can be easily formed between the gas exhaust guiding portion 450 and the lead film 400.

[0059] 4, the first sealing portion 251 in the sealing portion 250 may have a pattern that is recessed with respect to the second sealing portion 255. As an example, as shown in FIGS. 3 and 4(a), the first sealing portion 251 in the sealing portion 250 may have a pattern that is recessed outward with respect to the inside of the sealing portion 250. As another example, as shown in FIG. 4(b), the first sealing portion 251 may have a pattern that is recessed inward with respect to the outside of the sealing portion 250, opposite to the first sealing portion 251 formed in FIGS. 3 and 4(a). In this case, the sealing portion 250 may include a recess 250A in the first sealing portion 251. As another example, as shown in (a) and (b) of Figures 4, the first sealing portion in the sealing portion 250 may have both a pattern that is recessed outwardly based on the inside of the sealing portion 250 and a pattern that is recessed inwardly based on the outside of the sealing portion 250.

[0060] As described above, unlike the second sealing portion 255, the sealing portion 250 has a recessed pattern formed in the first sealing portion 251, so that there are portions on the lead film 400 that are not sealed by the first sealing portion 251. That is, the sealing strength between the lead film 400 and the sealing portion 250 is reduced, and the lead film 400 is easily peeled off from the gas exhaust guiding portion 450 due to the internal pressure when the internal pressure increases, and a gas exhaust path is easily formed between the gas exhaust guiding portion 450 and the lead film 400.

[0061] 4(a), the sealing portion 250 may have a pattern of the first sealing portion 251, and the portion of the lead film 400 that is not sealed by the first sealing portion 251 may directly contact the internal gas when the internal pressure increases. That is, the lead film 400 may be more easily peeled off from the gas exhaust guiding portion 450 due to the internal pressure.

[0062] However, the pattern of the sealing portion 250 is not limited to this, and any pattern in which a portion of the sealing portion 250 is not sealed and a portion of the lead film 400 located on the gas exhaust guide portion 450 is exposed may be included in this embodiment.

[0063] The following description will be based on the battery cell in Fig. 4(a). Fig. 5 is a cross-sectional view of the battery cell in Fig. 4(a) taken along line AA' in Fig. 3.

[0064] 3, 4(a), and 5, the battery case 200 may further include a storage extension 210A. More specifically, in the battery case 200, the storage extension 210A may be located between the first sealing portion 251 and the storage portion 210. In other words, the storage extension 210A may be a region that extends in a direction in which the electrode lead 300 protrudes with respect to the storage portion 210 and is connected to an end of the first sealing portion 251.

[0065] In addition, in the battery case 200, the end of the storage extension part 210A may be located outside the end of the storage part 210 based on the outside of the battery case 200. In other words, based on the inside of the battery case 200, the end of the storage part 210 is connected to the end of the second sealing part 255, and the end of the storage extension part 210A is connected to the end of the first sealing part 251. In this case, based on the inside of the battery case 200, the end of the first sealing part 251 is located outside the end of the second sealing part 255, so that the end of the storage extension part 210A may be located outside the end of the storage part 210. In this case, the angle at which the storage extension part 210A is inclined based on the lead film 400 may be smaller than the angle at which the storage part 210 is inclined.

[0066] As configured above, the battery cell 100 according to this embodiment includes a storage extension portion 210A that is relatively longer than the length of the side of the storage portion 210. This allows the lead film 400 to peel off from the gas discharge guide portion 450 due to internal pressure in the space between the lead film 400 and the storage extension portion 210A, making it possible to easily form a gas discharge path between the gas discharge guide portion 450 and the lead film 400.

[0067] 4 and 5, the gas discharge guiding portion 450 may extend along the protruding direction of the electrode lead 300. More specifically, in the gas discharge guiding portion 450, an end portion of the gas discharge guiding portion 450 adjacent to the outside of the battery case 200 may be covered with the lead film 400. In other words, the end portion of the gas discharge guiding portion 450 adjacent to the outside of the battery case 200 is not exposed to the outside of the battery case 200.

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

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

[0070] 5, the thickness H (height in the Z-axis direction) of the lead film 400 on the upper surface of the gas discharge guide portion 450 may be 100 μm to 300 μm or 100 μm to 200 μm. When the thickness H of the lead film 400 satisfies the above-mentioned range, the gas inside the battery case 200 is more easily discharged to the outside.

[0071] 5, the width W of the lead film 400 covering the front surface of the gas discharge guide portion 450 based on the protruding direction of the electrode lead 300 may be 2 mm or more, or 2 mm to 3 mm. When the width W of the lead film 400 satisfies the above-mentioned range, the lead film 400 can be prevented from being broken in the process of gas generated inside the battery case 200 being discharged to the outside.

[0072] In addition, the thickness D of the gas discharge guiding part 450 may be 50 μm to 150 μm. When the thickness of the gas discharge guiding part 450 satisfies the above-mentioned range, the gas inside the battery case 200 can be more easily discharged to the outside. FIG. 6 shows various shapes of the gas discharge guiding part. The gas discharge guiding part 450 may be formed in a predetermined pattern to discharge the gas inside the battery case 200.

[0073] For example, the gas discharge guide portion 450 may have a rectangular shape extending along the protruding direction of the electrode lead 300 as shown in Fig. 4. However, without being limited thereto, the gas discharge guide portion 450 may have various shapes such as a circular shape as shown in Fig. 6(a), an elliptical shape as shown in Fig. 6(b), a linear shape, a curved shape, etc.

[0074] As another example, the gas discharge inducing part 450 may include a first gas discharge inducing part 450a extending along the protruding direction of the electrode lead 300 as shown in FIG. 6(c), and a second gas discharge inducing part 450b extending in a direction perpendicular to the protruding direction of the electrode lead 300. In particular, the first gas discharge inducing part 450a and the second gas discharge inducing part 450b may be connected to each other. Here, the second gas discharge inducing part 450b may be located outside the sealing part 250 and inside the lead film 400 with respect to the sealing part 250 as shown in FIG. 6(c), or may be located inside the sealing part 250 and outside the lead film 400 with respect to the sealing part 250 as shown in FIG. 6(d). Alternatively, the second gas discharge inducing part 450b may be located both outside and inside the lead film 400 with respect to the sealing part 250 as shown in FIG. 6(e). However, the gas exhaust guide portion 450 is not limited to the above shape, and may be inserted into the lead film 400 in any suitable shape.

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

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

[0077] In this way, by adjusting the number of gas exhaust guiding parts 450 inserted in the lead film 400, the gas exhaust performance of the gas exhaust guiding parts 450 and the durability and airtightness of the lead film 400 can be controlled. Also, the number of gas exhaust guiding parts 450 can be minimized as necessary, simplifying the manufacturing process and reducing costs. FIG. 7 is an enlarged view of the area indicated by the two-dot chain line in FIG. 5, and FIGS. 8 and 9 are views showing gas exhaust paths formed at the interface between the lead film and the gas exhaust guiding parts in FIG. 7. FIG. 10 is a perspective view showing the gas exhaust paths in FIG. 9. In FIGS. 8 and 10, the gas movement paths are indicated by dotted arrows.

[0078] 7 to 9, in this embodiment, a gas discharge path may be formed at the interface between the gas discharge guiding portion 450 and the lead film 400. More specifically, as shown in FIG. 7, a portion of the lead film 400 that is not sealed by the first sealing portion 251 may be pressurized by the internal gas when the internal pressure of the battery cell 100 increases. The portion of the lead film 400 that is not sealed by the first sealing portion 251 moves in the direction of the thick arrow in FIG. 7 even with a small internal pressure. Thereafter, as shown in FIG. 8, the interface between the lead film 400 and the gas discharge guiding portion 450 may peel off, and the peeled portion 400A of the lead film 400 may be located adjacent to the housing extension portion 210A.

[0079] Thereafter, by applying further pressure to the interface between the peeled portion 400A of the lead film 400 and the gas discharge guiding portion 450, at least a portion of the interface between the lead film 400 and the gas discharge guiding portion 450 is separated as shown in Fig. 9. In this manner, the gas discharge path may refer to a space in which at least a portion of the interface between the gas discharge guiding portion 450 and the lead film 400 is separated by the pressure of gas generated in the battery case 200. That is, as shown in the direction of the dotted arrow in Fig. 9, the gas discharge path may refer to a path in which gas flows into a space in which the interface between the gas discharge guiding portion 450 and the lead film 400 is separated, and is discharged to the outside.

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

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

[0082] 10, the lead film 400 located on the gas discharge guiding portion 450 includes a portion that is not sealed by the first sealing portion 251, so that the lead film 400 can be easily peeled off from the gas discharge guiding portion 450 even with a relatively low internal pressure. That is, the gas discharge path can be easily formed in the present embodiment, and the gas discharge performance is further improved.

[0083] However, the gas exhaust path may be included in the present embodiment not only when at least a part of the interface between the upper surface of the gas exhaust guiding part 450 and the lead film 400 is separated as shown in FIG. 9, but also when at least a part of the interface between the lower surface of the gas exhaust guiding part 450 and the lead film 400 is separated. As an example, the gas exhaust guiding part 450 may be a film layer made of at least one of polyimide (PI) and polyethylene terephthalate (PET). As another example, the gas exhaust guiding part 450 may be a coating layer made of liquid resin. However, the shape or material of the gas exhaust guiding part 450 is not limited thereto, and may be included in the present embodiment as long as the adhesive strength at the interface between the gas exhaust guiding part 450 and the lead film 400 is relatively lower than the adhesive strength between the lead film 400 and other components.

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

[0085] 4 and 5, one end of the gas discharge guiding part 450 may be located more inward than the inner surface of the sealing part 250 based on the protruding direction of the electrode lead 300. In this specification, the inner surface of the sealing part 250 means an end of the sealing part 250 adjacent to the inside of the battery case 200, and being located more inward than the inner surface of the sealing part 250 means being located more inward than the inner surface of the sealing part 250. When one end of the gas discharge guiding part 450 is located more inward than the inner surface of the sealing part 250, gas can easily flow into the gas discharge guiding part 450 without being interfered with by the sealing part 250.

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

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

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

[0089] Also, the gas exhaust guiding unit 450 may further include a material having a function of absorbing or adsorbing moisture flowing in from the outside or hydrofluoric acid generated inside. More specifically, the gas exhaust guiding unit 450 may further include a getter material. Here, the getter material may refer to a material that can be exhausted by using the action of adsorbing gas by a chemically activated metal film. As an example, the getter material is calcium oxide (CaO), lithium chloride (LiCl), silica (SiO 2 ), barium oxide (BaO), barium (Ba), and calcium (Ca). As another example, the getter material may have a metal organic framework (MOF) structure. However, the getter material is not limited thereto and may include all types of materials generally classified as getter materials.

[0090] In this manner, in the present embodiment, the gas exhaust guiding unit 450 further includes a material capable of absorbing or adsorbing moisture or hydrofluoric acid, so that the gas exhaust guiding unit 450 can more easily exhaust gas generated inside the battery cell 100 to the outside while further minimizing the penetration of moisture or hydrofluoric acid flowing into the inside of the battery cell 100 from the outside of the battery cell 100.

[0091] In an embodiment of the present invention, the gas discharge guiding unit 450 may have a gas permeability of 40 barrer or more at 60° C. For example, the carbon dioxide permeability of the gas discharge guiding unit 450 may satisfy the above range.

[0092] For example, the gas discharge guide 450 may include at least one of polyolefin-based, fluorine-based, and porous ceramic-based materials that satisfy the above-mentioned gas permeability range. The polyolefin-based material may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinyldifluoride (PVDF). The fluorine-based material may include one or more materials selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride.

[0093] In one embodiment of the present invention, the gas permeability of the lead film 400 may be 20 to 60 Barrer, or 30 to 40 Barrer at 60° C. For example, the carbon dioxide permeability of the lead film 400 may satisfy the above-mentioned range. In addition, the gas permeability may satisfy the above-mentioned range at 60° C., based on the thickness H of the lead film 400 being 200 μm. When the gas permeability of the lead film 400 satisfies the above-mentioned range, gas generated inside the battery cell can be more effectively discharged.

[0094] As used herein, gas permeability may be measured by ASTM F2476-20.

[0095] In an embodiment of the present invention, the moisture permeation amount of the lead film 400 may be 0.02g to 0.2g, or 0.02g to 0.04g, or 0.06g, or 0.15g, over 10 years at 25° C. and 50% RH. When the moisture permeation amount of the lead film 400 satisfies the above range, the permeation of moisture entering from the lead film 400 can be more effectively prevented.

[0096] In one embodiment of the present invention, the lead film 400 may have a gas permeability of 20 to 60 Barrers at 60° C. and a moisture permeation amount of 0.02 g to 0.2 g over 10 years at 25° C. and 50% RH. When the gas permeability and moisture permeation amount of the lead film 400 satisfy the above-mentioned ranges, it is possible to more effectively prevent moisture permeation from the outside while discharging gas generated inside the battery cell 100.

[0097] The amount of moisture permeation of the lead film 400 may be measured according to ASTM F 1249. At this time, the measurement may be performed using an officially certified device from MCOON.

[0098] In one embodiment of the present invention, the lead film 400 may be made of an adhesive composition including at least one of a polyolefin-based material, an epoxy, and polyvinyl chloride (PVC). The polyolefin-based material may be polyethylene (PE), polypropylene (PP), etc. For example, the lead film 400 may include polyethylene, polypropylene, etc. that meets the above-mentioned gas permeability and / or moisture penetration values.

[0099] Furthermore, by making the lead film 400 from the above-mentioned material, the airtightness of the battery cell 100 can be maintained and leakage of the internal electrolyte can be prevented.

[0100] Hereinafter, a battery cell according to another embodiment of the present invention will be described. However, since most of the description of the battery cell 100 described above can be applied to the battery cell according to this embodiment, the description will be centered on the gas exhaust guide 450 inserted into the lead film 400 as a difference from the battery cell 100.

[0101] FIG. 11 is a cross-sectional view taken along line AA' of FIG. 3, showing a battery cell according to another embodiment of the present invention.

[0102] 3 and 11, in this embodiment, unlike FIG. 5, a gas exhaust guiding part 450' may be located on the electrode lead 300'. More specifically, a separate lead film 400' is not located between the gas exhaust guiding part 450' and the electrode lead 300'. That is, the gas exhaust guiding part 450' may be inserted into one surface of the lead film 400' adjacent to the electrode lead 300' and may be located in contact with the electrode lead 300'. In other words, in this embodiment, the gas exhaust guiding part 450' may be attached or fixed onto the electrode lead 300', and then the lead film 400' may cover the outer surface of the gas exhaust guiding part 450'.

[0103] Since the gas exhaust guide portion 450' is positioned adjacent to the electrode lead 300', the thickness of the lead film 400' covering the gas exhaust guide portion 450' is relatively reduced, which has the advantage of reducing manufacturing costs and simplifying the manufacturing process.

[0104] Also, an adhesive layer 470' may be formed between the gas exhaust guiding portion 450' and the electrode lead 300'. Here, the adhesive layer 470' may extend along the interface between the gas exhaust guiding portion 450' and the electrode lead 300'. In this case, the adhesive layer 470' may be formed on the entire or part of the interface between the gas exhaust guiding portion 450' and the electrode lead 300'.

[0105] For example, the adhesive layer 470′ may be an adhesive tape or an adhesive binder, but is not limited thereto and may be any material having adhesive properties capable of fixing the gas exhaust guide unit 450′ and the electrode lead 300′ together.

[0106] As a result, the gas discharge guiding unit 450' is stably fixed to the electrode lead 300' by the adhesive layer 470'. That is, by forming the adhesive layer 470' having a relatively high adhesive strength between the gas discharge guiding unit 450' and the electrode lead 300', peeling due to an increase in the internal pressure of the battery cell 100 can be prevented, and the sealing strength of the battery cell 100 can be further improved.

[0107] Fig. 12 is an enlarged view of the area enclosed by the two-dot chain line in Fig. 11, and Fig. 13 and Fig. 14 are views showing the gas discharge path formed at the interface between the lead film and the gas discharge guide part in Fig. 12. In Fig. 13 and Fig. 14, the gas movement path is indicated by dotted arrows.

[0108] 12 to 14, in this embodiment, a gas discharge path may be formed at the interface between a gas discharge guide portion 450' and a lead film 400', similarly to Figures 7 to 10. However, in this embodiment, unlike Figures 7 to 10, the gas discharge guide portion 450' is located in contact with the electrode lead 300', and an adhesive layer 470' is formed between the gas discharge guide portion 450' and the electrode lead 300', so that a gas discharge path is not formed at the interface between the gas discharge guide portion 450' and the electrode lead 300'.

[0109] More specifically, in this embodiment, the adhesive strength between the gas discharge guide portion 450' and the lead film 400' is smaller than the adhesive strength between the adhesive layer 470' and the gas discharge guide portion 450' and / or the adhesive strength between the adhesive layer 470' and the electrode lead 300'.

[0110] More specifically, in this embodiment, when the pressure inside the battery cell 100 increases, the adhesive strength at the interface between the gas discharge guide portion 450' and the lead film 400' is relatively weaker than the adhesive strength between the lead film 400' and other components, so that the portion of the lead film 400 that is not sealed by the first sealing portion 251 moves in the direction of the thick arrow in Fig. 12 even due to small internal pressure. Therefore, at least a portion of the interface between the gas discharge guide portion 450' and the lead film 400' may be separated from each other due to the internal pressure of the battery cell 100 as shown in Fig. 13.

[0111] Furthermore, in this embodiment, the adhesive strength at the interface between the gas discharge guide portion 450' and the lead film 400' is smaller than the adhesive strength between the gas discharge guide portion 450' and the adhesive layer 470' and / or the adhesive strength between the adhesive layer 470' and the electrode lead 300', so that peeling off at the interface between the gas discharge guide portion 450' and the electrode lead 300' can be prevented when the internal pressure of the battery cell 100 increases.

[0112] That is, in this embodiment, only the interface between the gas exhaust guide 450' and the lead film 400' is peeled off to form a gas exhaust path, so that it is possible to increase the sealing strength of the battery cell 100 while maintaining the gas exhaust performance of the gas exhaust path. In addition, due to the high sealing strength, the vent pressure when gas generated within the battery cell 100 is exhausted to the outside is also increased, thereby improving safety.

[0113] Furthermore, in this embodiment, the interface between the lead film 400' and the gas discharge guide portion 450' can be more easily peeled off even at a relatively low internal pressure due to the high adhesive strength between the gas discharge guide portion 450' and the adhesive layer 470' and / or the high adhesive strength between the adhesive layer 470' and the electrode lead 300', as well as the peeling portion 400A' of the lead film 400. That is, in this embodiment, there is an advantage that the gas discharge path can be more easily formed and the gas discharge performance is further improved. Hereinafter, a battery cell according to a comparative example of the present invention will be mainly described. The comparative example will be described in comparison with the embodiment shown in Figs. 3 to 10, but it can also be described in comparison with the embodiment shown in Figs. 11 to 14.

[0114] Fig. 15 is an enlarged view of the region enclosed by the two-dot chain line in Fig. 1 in a comparative example. Fig. 16 is a cross-sectional view taken along line a-a' in Fig. 1 in a comparative example. Fig. 17 is an enlarged view of the region enclosed by the two-dot chain line in Fig. 16.

[0115] 15 to 17, the battery cell 10 according to the comparative example is the same as the battery cell 10 of Fig. 1 and Fig. 2, except for the configuration including the gas discharge guiding unit 45 as in the embodiment of the present invention. The following description will focus on the gas discharge guiding unit 45.

[0116] 15 and 17, in the battery cell 10 according to the comparative example, a sealing portion 25 is formed on the lead film 40 where the gas discharge guiding portion 45 is located, and unlike in Figures 3 to 10, the width of the sealing portion 25 is constant regardless of the position of the sealing portion 25. As a result, the entire lead film 40 located on the gas discharge guiding portion 45 is sealed by the sealing portion 25.

[0117] 17, in the battery cell 10 according to the comparative example, as described above, the lead film 40 located on the gas discharge guiding portion 45 is entirely sealed by the sealing portion 25, and therefore, at a relatively low internal pressure, the interface between the lead film 40 and the gas discharge guiding portion 45 is unlikely to peel off due to the gas inside the battery cell 10. That is, in the case of the battery cell 10 according to the comparative example, a relatively high internal pressure is required to form a gas discharge path at the interface between the lead film 40 and the gas discharge guiding portion 45, which may reduce the gas discharge performance and safety of the battery cell 10.

[0118] 3 to 10, in the battery cell 100 according to the present embodiment, the width D1 of the first sealing portion 251 located on the gas discharge guiding portion 450 is narrower than the width D2 of the second sealing portion 255, and the lead film 400 located on the gas discharge guiding portion 450 includes a portion that is not sealed by the first sealing portion 251. That is, unlike the comparative example, in the present embodiment, the portion of the lead film 400 that is not sealed by the first sealing portion 251 is in direct contact with the gas inside the battery cell 100, so that the lead film 400 can be easily peeled off from the gas discharge guiding portion 450 even at a relatively low internal pressure. That is, the present embodiment has the advantage that the gas discharge path can be more easily formed and gas discharge performance can be further improved.

[0119] A battery module according to another embodiment of the present invention includes the above-mentioned battery cell. Meanwhile, one or more of the battery modules according to the present embodiment may be packaged in a pack case to form a battery pack.

[0120] The above-mentioned battery module and the battery pack including the same may be applied to various devices. Such devices may be means of transportation such as electric bicycles, electric cars, hybrid cars, etc. However, the present invention is not limited thereto, and the battery module and the battery pack including the same may be applied to various devices that can use the battery module, and these are also within the scope of the present invention.

[0121] Although a preferred embodiment of the present invention has been described in detail above, it goes without saying that the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention as claimed in the claims also fall within the scope of the present invention. [Explanation of symbols]

[0122] 100: Battery cell 110: Electrode assembly 200: Battery case 210: Storage section 250: Sealing part 300: Electrode lead 400: Lead film 450: Gas exhaust induction section

Claims

1. a battery case including a receiving portion in which the electrode assembly is mounted and a sealing portion formed by sealing an outer periphery of the receiving portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing part; a lead film located at a portion corresponding to the sealing portion at at least one of an upper portion and a lower portion of the electrode lead, A gas exhaust guide portion is inserted into the lead film, The sealing portion includes a first sealing portion located on the gas exhaust guide portion and a second sealing portion located on both sides of the first sealing portion, A width of the first sealing portion is narrower than a width of the second sealing portion based on a protruding direction of the electrode lead, A battery cell, in which when the internal pressure of the battery cell increases, the gas discharge guide portion and the lead film are peeled away from each other, forming a gas discharge path at the interface between the gas discharge guide portion and the lead film.

2. The battery cell of claim 1 , wherein a length of the first sealing portion is longer than a length of the gas discharge guiding portion in a direction perpendicular to a protruding direction of the electrode lead.

3. The battery cell of claim 2 , wherein the gas discharge guide portion is located at a center of the first sealing portion.

4. The battery cell of claim 1 , wherein the first sealing portion has a recessed pattern with respect to the second sealing portion.

5. The battery cell of claim 4 , wherein the first sealing portion has a pattern that is recessed outward from an inner side of the sealing portion.

6. The battery cell according to claim 5 , wherein a receiving extension portion is located between the first sealing portion and the receiving portion.

7. The battery cell according to claim 6 , wherein an end of the storage extension portion is positioned outside an end of the storage portion with respect to an outside of the battery case.

8. 8. The battery cell according to claim 1, wherein the gas discharge guide portion extends along a protruding direction of the electrode lead, and an end portion of the gas discharge guide portion adjacent to an outside of the battery case is covered and wrapped with the lead film.

9. The battery cell according to claim 8 , wherein an end of the gas discharge guide portion adjacent to an inner side of the battery case is exposed to the inside of the battery case.

10. The battery cell according to claim 1 , wherein an adhesive force between the gas discharge guide portion and the lead film is smaller than an adhesive force between the lead film and an electrode lead or an adhesive force between the lead film and the sealing portion.

11. The battery cell according to claim 10 , wherein the gas discharge guide portion is a film layer made of at least one of polyimide and polyethylene terephthalate.

12. The battery cell according to claim 10 , wherein the gas discharge guide portion is a coating layer made of a liquid resin.

13. The gas exhaust guide portion is made of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO ２ 11. The battery cell of claim 10, further comprising a getter material comprising at least one of: barium oxide (BaO), barium (Ba), and calcium (Ca).

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

15. The battery cell of claim 14 , wherein an adhesive strength between the gas discharge guide portion and the lead film is smaller than at least one of an adhesive strength between the adhesive layer and the gas discharge guide portion and an adhesive strength between the adhesive layer and the electrode lead.

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

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

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

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

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

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