Battery cell and battery module including the same

Abstract

To provide a battery cell with improved gas discharge performance, and a battery module including the same.SOLUTION: A battery cell according to one aspect of the present invention includes: a battery case including an accommodation portion in which an electrode assembly is mounted, and a sealing portion formed by sealing an outer periphery of the accommodation portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding out of the battery case via the sealing portion; and a lead film located at a portion corresponding to the sealing portion in at least one of an upper portion and a lower portion of the electrode lead. A gas discharge guiding unit is inserted in the lead film, the sealing portion includes a first sealing portion located on the gas discharge guiding unit and a second sealing portion located at both sides of the first sealing portion, and based on a protruding direction of the electrode lead, a width of the first sealing portion is smaller than a width of the second sealing portion.SELECTED DRAWING: Figure 3

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 having 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 all of the content disclosed in the specifications and drawings of the applications is incorporated herein by reference.

Background Art

[0002] As the technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source has been rapidly increasing. In particular, secondary batteries have attracted much attention not only as an energy source for mobile devices such as mobile phones, digital cameras, notebook computers, and wearable devices, but also as an energy source for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0003] Such secondary batteries are classified into cylindrical batteries and prismatic batteries in which an electrode assembly is housed in a cylindrical or prismatic metal can depending on the shape of the battery case, and pouch-type batteries in which the electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet. Here, the electrode assembly housed in the battery case includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and is a power generation element capable of charge and discharge, and is divided 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, and a stacked type in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator interposed therebetween.

[0004] Among them, in particular, pouch-type batteries having 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 because of their low manufacturing cost, light weight, and easy deformability.

[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. 1.

[0006] Referring to FIGS. 1 and 2, a conventional battery cell 10 includes a battery case 20 having a structure in which an electrode assembly 11 is housed in a housing portion 21 and a sealing portion 25 with its outer periphery sealed. 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 outside the battery case 20 through the sealing portion 25. A lead film 40 is positioned between the upper and lower portions of the electrode lead 30 and the sealing portion 25.

[0007] However, in recent years, with the increase in the energy density of battery cells, there is a problem that the amount of gas generated inside the battery cell also increases. In the case of the conventional battery cell 10, there are no components capable of discharging the gas generated inside the battery cell, and there is a risk of a venting phenomenon in which the battery case 20 ruptures due to gas generation during long-term storage. Furthermore, a battery cell damaged by the venting phenomenon may allow moisture to penetrate inside, causing side reactions, leading to a decrease in battery performance and additional gas generation. Therefore, there is a high need to develop a battery cell with improved external gas discharge ability for the gas generated inside the battery cell. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The problem to be solved by the present invention is to provide a battery cell with improved gas discharge performance and a battery module including the same.

[0009] The problem to be solved by the present invention is not limited to the problems described above, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. MEANS FOR SOLVING THE PROBLEM

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

[0011] Based on the direction perpendicular to the protruding direction of the electrode lead, the length of the first sealing portion may be longer than the length of the gas discharge guiding portion.

[0012] The gas discharge guiding 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 with respect to the inside of the sealing portion.

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

[0016] Based on the outside of the battery case, the end of the storage extension portion may be located outside the end of the storage portion.

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

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

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

[0020] An adhesive force between the gas discharge guiding portion and the lead film may be smaller than an adhesive force between the lead film and the electrode lead or an adhesive force between the lead film and the sealing portion.

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

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

[0023] The gas discharge guiding portion may further include a getter material containing at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO 2 ), barium oxide (BaO), barium (Ba), and calcium (Ca).

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

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

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

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

[0028] The water penetration amount of the lead film can be 0.02 g to 0.2 g in 10 years at 25°C and 50% RH.

[0029] The gas permeability of the gas discharge guiding part can be 40 barrer or more at 60°C.

[0030] A battery module according to another aspect of the present invention includes the battery cell described above.

Advantages of the Invention

[0031] According to an embodiment of the present invention, by providing a battery cell in which the length of the sealing part located on the gas discharge guiding part is relatively short and a battery module including the same, the gas discharge performance can be improved.

[0032] Specifically, according to an embodiment of the present invention, a gas discharge path can be formed at the interface between the gas discharge guiding part and the lead film, which not only makes the manufacturing process relatively easy, but also can effectively discharge the gas in the battery cell to the outside.

[0033] According to another embodiment of the present invention, the sealing part includes a first sealing part and a second sealing part. By making the width of the first sealing part different from the width of the second sealing part, the sealing strength between the lead film and the sealing part is reduced, so that when the internal pressure rises, the lead film is easily peeled off from the gas discharge guiding part by the internal pressure, and a gas discharge path can be easily formed between the gas discharge guiding part and the lead film.

[0034] According to still another embodiment of the present invention, a portion that is not sealed by the first sealing part is formed on the lead film, so that the corresponding portion comes into direct contact with the internal gas when the internal pressure rises. Therefore, the lead film can be more easily peeled off from the gas discharge guiding part by the internal pressure.

[0035] According to still other embodiments of the present invention, by adjusting the shape of the gas discharge guiding portion, the gas discharge performance of the gas discharge guiding portion, the durability and airtightness of the lead film can be controlled. Further, if necessary, the shape of the gas discharge guiding portion can be changed to simplify the manufacturing process and reduce costs.

[0036] According to still other embodiments of the present invention, by setting the gas permeability and moisture penetration amount of the lead film within a predetermined range, while discharging the gas generated inside the battery cell, moisture penetration from the outside can be more effectively prevented.

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

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0039] Hereinafter, various embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them with reference to the drawings. The present invention can be embodied in various different forms and is not limited to the embodiments described later.

[0040] To clearly explain the present invention, parts not related to the explanation will be omitted, and the same reference numerals will be given to the same or similar components throughout the specification.

[0041] Also, the sizes and thicknesses of the respective configurations shown are arbitrarily shown for convenience of explanation, and thus the present invention is not limited by the illustration. In the drawings, the thicknesses are enlarged to clearly show various layers and regions. And, in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

[0042] Also, throughout the specification, when a part states that a certain component "includes" something, this does not exclude other components unless otherwise specified, and it means that other components may further be included.

[0043] Also, throughout the specification, when referring to a "plan view", it means the case of looking at the target part from above, and when referring to a "cross-sectional view", it means the case of looking at the cross-section obtained by vertically cutting the target part from the side.

[0044] Hereinafter, a battery cell according to an embodiment of the present invention will be described. However, here, the description is made with reference to one end portion of the battery cell, but it is not necessarily limited thereto, and the same or similar description may be applicable to the other end portion of the battery cell.

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

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

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

[0048] The electrode assembly 110 can have a jelly roll type (wound type), a laminated type (stack type), or a composite type (laminated / folded type) structure. More specifically, the electrode assembly 110 can 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 outside the battery case 200 through the sealing portion 250. Further, the lead film 400 is located at a portion corresponding to the sealing portion 250 at at least one of the upper and lower portions of the electrode lead 300. Thereby, the lead film 400 can prevent a short circuit from occurring in the electrode lead 300 during heat fusion or press fusion together with the sealing portion 250, and can improve the sealing property between the sealing portion 250 and the electrode lead 300.

[0050] Referring to FIG. 3, the lead film 400 can have a width wider than that of the electrode lead 300. Here, the width 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 direction (Y-axis direction) orthogonal to the protruding direction (X-axis direction) of the electrode lead 300, and the width 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 direction orthogonal to the protruding direction of the electrode lead 300.

[0051] The lead film 400 may have a length that is longer than the length of the sealing portion 250 and shorter than the length of the electrode lead 300, with reference to 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. Thereby, the lead film 400 can prevent the electrical connection of the electrode lead 300 from being obstructed and prevent the side surface of the electrode lead 300 from being exposed to the outside.

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

[0053] Referring to FIGS. 3 and 4, a gas discharge guiding portion 450 is inserted into the lead film 400, and the sealing portion 250 includes a first sealing portion 251 located on the gas discharge guiding portion 450 and second sealing portions 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 discharge guiding portion 450 is not located. More specifically, the first sealing portion 251 and the second sealing portions 255 may be integrated with each other.

[0054] Also, referring to FIG. 4, with reference to the protruding direction of the electrode lead 300, the width D1 of the first sealing portion 251 is narrower than the width D2 of the second sealing portion 255. 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 in contact with the lead film 400 is narrower than the width D2 of the surface of the second sealing portion 255 in contact with the lead film 400. That is, with reference to 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] Also, referring to FIG. 4, with reference to the direction perpendicular to the protruding direction of the electrode lead 300, the length L1 of the first sealing portion 251 can be longer than the length L2 of the gas discharge guiding portion 450. Here, the length 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 direction orthogonal to the protruding direction of the electrode lead 300. The length of the gas discharge guiding portion 450 means the maximum value of the distance between one end and the other end of the gas discharge guiding portion 450 in the direction orthogonal to the protruding direction of the electrode lead 300. In other words, with reference to the direction perpendicular to 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. More specifically, the gas discharge guiding portion 450 can be located at the center of the first sealing portion 251. However, the position of the gas discharge guiding portion 450 is not limited to this, and as long as it is located within the first sealing portion 251, it 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 of the gas discharge path described later while maintaining the sealing performance of the battery cell 100.

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

[0058] That is, the portion of the lead film 400 that is not sealed by the first sealing portion 251 has a low sealing strength of the sealing portion 250, and when the internal pressure rises, the lead film 400 is easily peeled off from the gas discharge guiding portion 450 by the internal pressure, and a gas discharge path can be easily formed between the gas discharge guiding portion 450 and the lead film 400.

[0059] Also, as shown in FIG. 4, in the sealing portion 250, the first sealing portion 251 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), in the sealing portion 250, the first sealing portion 251 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), contrary to the first sealing portion 251 formed in FIGS. 3 and 4(a), the first sealing portion 251 may have a pattern that is recessed inward with respect to the outside of the sealing portion 250. In this case, the sealing portion 250 may include a recessed portion 250A in the first sealing portion 251. Also, as another example, as shown in FIGS. 4(a) and (b), in the sealing portion 250, the first sealing portion may have both a pattern that is recessed outward with respect to the inside of the sealing portion 250 and a pattern that is recessed inward with respect to the outside of the sealing portion 250.

[0060] As described above, since the sealing portion 250 has a pattern recessed in the first sealing portion 251, which is different from the second sealing portion 255, there is a portion on the lead film 400 that is 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 when the internal pressure rises, the lead film 400 is likely to peel off from the gas discharge guiding portion 450 due to the internal pressure, and a gas discharge path is likely to be formed between the gas discharge guiding portion 450 and the lead film 400.

[0061] More desirably, the sealing portion 250 may have the pattern of the first sealing portion 251 as shown in FIG. 4(a), and the portion of the lead film 400 that is not sealed by the first sealing portion 251 may be in direct contact with the internal gas when the internal pressure rises. That is, the lead film 400 can be more easily peeled off from the gas discharge guiding portion 450 by the internal pressure.

[0062] However, the pattern of the sealing portion 250 is not limited to this, and as long as a portion where a part of the sealing portion 250 is not sealed is formed and a part of the lead film 400 located on the gas discharge guiding portion 450 is exposed, it may be included in this embodiment.

[0063] Hereinafter, description will be made based on the battery cell of FIG. 4(a). FIG. 5 is a cross-sectional view taken along line A-A' of FIG. 3 in the battery cell of FIG. 4(a).

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

[0065] Also, in the battery case 200, with reference to the outside of the battery case 200, the end of the storage extension part 210A may be located outside the end of the storage part 210. In other words, with reference to 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, with reference to the inside of the battery case 200, when the end of the first sealing part 251 is located outside the end of the second sealing part 255, the end of the storage extension part 210A may be located outside the end of the storage part 210. At this time, with reference to the lead film 400, the angle at which the storage extension part 210A is inclined may be smaller than the angle at which the storage part 210 is inclined.

[0066] As described above, the battery cell 100 according to the present embodiment includes the storage extension part 210A that is relatively longer than the length of the side surface of the storage part 210. Thus, in the space between the lead film 400 and the storage extension part 210A, the lead film 400 can be peeled off from the gas discharge guiding part 450 due to the internal pressure, and a gas discharge path can be easily formed between the gas discharge guiding part 450 and the lead film 400.

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

[0068] Also, the end of the gas discharge guiding part 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 part 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 inside the battery case 200 more than the end of the lead film 400.

[0069] Thus, 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 outside 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. Further, 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 inside the battery case 200, and the gas generated inside the battery cell 100 easily flows into the gas discharge path formed by the gas discharge guiding portion 450 and is effectively discharged outward.

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

[0071] Referring further to FIG. 5, based on the protruding direction of the electrode lead 300, the width W of the lead film 400 covering the front surface of the gas discharge guiding portion 450 can be 2 mm or more or 2 mm to 3 mm. When the width W of the lead film 400 satisfies the above-described range, it is possible 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.

[0072] Also, the thickness D of the gas discharge guiding portion 450 can be 50 μm to 150 μm. When the thickness of the gas discharge guiding portion 450 satisfies the above-described 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 portion. The gas discharge guiding portion 450 can be formed in a predetermined pattern to discharge the gas inside the battery case 200.

[0073] As an example, as shown in FIG. 4, the gas discharge guiding portion 450 may be rectangular and extend along the protruding direction of the electrode lead 300. However, it is not limited thereto, and the gas discharge guiding portion 450 may have various shapes such as circular as shown in FIG. 6(a), elliptical as shown in FIG. 6(b), and other linear or curved shapes.

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

[0075] By adjusting the shape of the gas discharge guiding portion 450 inserted into the lead film 400 in this way, the gas discharge performance of the gas discharge guiding portion 450 and the durability and airtightness of the lead film 400 can be controlled. Further, the shape of the gas discharge guiding portion 450 can be changed as needed to simplify the manufacturing process and reduce costs.

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

[0077] By adjusting the number of the gas discharge guiding parts 450 inserted into the lead film 400 in this way, it is possible to control the gas discharge performance of the gas discharge guiding parts 450 and the durability and airtightness of the lead film 400. Further, if necessary, the number of the gas discharge guiding parts 450 can be minimized, the manufacturing process can be simplified, and the cost can be reduced. FIG. 7 is an enlarged view showing the two-dot chain line area in FIG. 5, and FIGS. 8 and 9 are views showing the gas discharge path formed at the interface between the lead film and the gas discharge guiding part in FIG. 7. FIG. 10 is a perspective view showing the gas discharge path in FIG. 9. In FIGS. 8 and 10, the moving path of the gas is indicated by dotted arrows.

[0078] Referring to FIGS. 7 to 9, in the present embodiment, a gas discharge path may be formed at the interface between the gas discharge guiding part 450 and the lead film 400. More specifically, as shown in FIG. 7, in the lead film 400, the portion not sealed by the first sealing part 251 may be pressurized by the internal gas when the internal pressure of the battery cell 100 rises. The portion of the lead film 400 not sealed by the first sealing part 251 will move in the direction of the thick arrow in FIG. 7 even under a small internal pressure. Then, as shown in FIG. 8, the interface between the lead film 400 and the gas discharge guiding part 450 peels off, and the peeled part 400A of the lead film 400 may be located adjacent to the storage extension part 210A.

[0079] After that, by applying further pressure to the interface between the peeled part 400A of the lead film 400 and the gas discharge guiding part 450, at least a part of the interface between the lead film 400 and the gas discharge guiding part 450 will be separated as shown in FIG. 9. In this way, the gas discharge path may mean a space in which at least a part of the interface between the gas discharge guiding part 450 and the lead film 400 is separated by the pressure of the gas generated in the battery case 200. That is, like the direction of the dotted arrow in FIG. 9, the gas discharge path may mean a path through which gas flows into the space where the interface between the gas discharge guiding part 450 and the lead film 400 is separated and is discharged to the outside.

[0080] Here, the adhesive force between the gas discharge guiding portion 450 and the lead film 400 may be smaller than the adhesive force between the lead film 400 and the electrode lead 300 or the adhesive force between the lead film 400 and the sealing portion 250. More specifically, when the pressure inside the battery case 200 increases due to the gas generated within the battery cell 100, since the adhesive force at the interface between the gas discharge guiding portion 450 and the lead film 400 is relatively smaller than the adhesive force between the lead film 400 and other components, at least a part of the interface between the gas discharge guiding portion 450 and the lead film 400 can be separated from each other by the pressure of the gas generated in the battery cell 100 as shown in FIGS. 8 and 9.

[0081] That is, in the present embodiment, due to the relatively low adhesive force between the gas discharge guiding portion 450 and the lead film 400, while the gas discharge guiding portion 450 and the lead film 400 are peeling off, the gas inside the battery cell 100 flows into the gas discharge passage formed at the interface between the gas discharge guiding portion 450 and the lead film 400, the gas moves along the gas discharge passage, and finally is discharged through the lead film 400. The gas flowing into the gas discharge passage can be discharged toward the outside due to the pressure difference with the outside.

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

[0083] However, the gas discharge path is included in this embodiment not only when at least a part of the interface between the upper surface of the gas discharge guiding portion 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 discharge guiding portion 450 and the lead film 400 is separated together. As an example, the gas discharge guiding portion 450 may be a film layer made of at least one of polyimide (PI) and polyethylene terephthalate (PET). As another example, the gas discharge guiding portion 450 may be a coating layer made of a liquid resin. However, the form of the gas discharge guiding portion 450 or the material constituting it is not limited to this, and any form or material in which the adhesive force between the gas discharge guiding portion 450 and the lead film 400 is relatively lower than the adhesive force between the lead film 400 and other components may be included in this embodiment.

[0084] As described above, due to the relatively low adhesive force between the gas discharge guiding portion 450 and the lead film 400, the battery cell according to this embodiment can form a gas discharge path at the interface between the gas discharge guiding portion 450 and the lead film 400. Not only is the manufacturing process relatively easy, but also the gas inside the battery cell 100 can be effectively discharged outward.

[0085] Referring further to FIGS. 4 and 5, with reference to the protruding direction of the electrode lead 300, one end of the gas discharge guiding portion 450 may be located inside the inner surface of the sealing portion 250. In this 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 being located inside the inner surface of the sealing portion 250 means being located inside the battery case 200 rather than the inner surface of the sealing portion 250. When one end of the gas discharge guiding portion 450 is located inside the inner surface of the sealing portion 250, it is not affected by the interference of the sealing portion 250, and gas can easily flow into the gas discharge guiding portion 450.

[0086] Also, based on the protruding direction of the electrode lead 300, the other end of the gas discharge guiding portion 450 may be located outside the outer surface of the sealing portion 250. In this specification, the outer surface of the sealing portion 250 means the end portion of the sealing portion 250 adjacent to the outside of the battery case 200, and being located outside the outer surface of the sealing portion 250 means being located outside the battery case 200 rather than the outer surface of the sealing portion 250. For example, a gap P is provided between the outer surface of the sealing portion 250 and the other end of the gas discharge guiding portion 450. When the other end of the gas discharge guiding portion 450 is located outside the outer surface of the sealing portion 250 in this way, the gas flowing into the gas discharge guiding portion 450 can be more easily discharged to the outside. For example, the other end of the gas discharge guiding portion 450 is not affected by interference from the sealing portion 250, and the gas flowing into the gas discharge guiding portion 450 can be more easily discharged to the outside.

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

[0088] Furthermore, as shown in FIG. 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 portion of the lead film 400 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 based on the protruding direction of the electrode lead 300, the width W of the lead film 400 covering the front surface of the gas discharge guiding portion 450 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 gas discharge becomes easier. Furthermore, when discharging gas, if the gas discharge path is completely covered by the sealing portion 250, the gas discharge will not be smooth. Therefore, providing a gap P between the outer surface of the sealing portion 250 and the other end of the gas discharge guiding portion 450 as described above has the effect of making the gas discharge smooth.

[0089] In addition, the gas discharge guiding portion 450 may further contain a substance having a function of absorbing or adsorbing moisture flowing in from the outside or hydrofluoric acid generated inside. More specifically, the gas discharge guiding portion 450 may further contain a getter material. Here, the getter material may mean a material that can be evacuated by using the action of adsorbing gas by a chemically activated metal film. As an example, the getter material may contain at least one of 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 structure of a metal-organic framework (MOF: Metal Organic Framework). However, the getter material is not limited to this, and may include all types of materials generally classified as getter materials.

[0090] Thus, in this embodiment, since the gas discharge guiding portion 450 further contains a substance capable of absorbing or adsorbing moisture or hydrofluoric acid, the gas discharge guiding portion 450 can more easily discharge the gas generated inside the battery cell 100 to the outside while minimizing the penetration of moisture or hydrofluoric acid flowing from the outside of the battery cell 100 into the inside of the battery cell 100.

[0091] In one embodiment of the present invention, the gas permeability of the gas discharge guiding portion 450 may be 40 barrer or more at 60°C. For example, the carbon dioxide permeability of the gas discharge guiding portion 450 may satisfy the above-described range.

[0092] For example, the gas discharge guiding portion 450 may contain at least one of a polyolefin-based, fluorine-based, and porous ceramic-based substance that satisfies the above-described range of gas permeability. The polyolefin-based substance may contain one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinylidene fluoride (PVDF). The fluorine-based substance may contain 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-described range. Also, based on the case where the thickness H of the lead film 400 is 200 μm, the gas permeability may satisfy the above-described range at 60°C. When the gas permeability of the lead film 400 satisfies the above-described range, the gas generated inside the battery cell can be discharged more effectively.

[0094] In this specification, the gas permeability can be measured by ASTM F2476-20.

[0095] In one embodiment of the present invention, the moisture penetration amount 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 over 10 years at 25°C and 50% RH. When the moisture penetration amount of the lead film 400 satisfies the above-described range, it is possible to more effectively prevent the penetration of moisture flowing in from the lead film 400.

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

[0097] The moisture penetration amount of the lead film 400 can be measured by adopting the ASTM F 1249 method. At this time, it can be measured using a device officially certified by MCOON.

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

[0099] Also, by being made of the above-described materials, the lead film 400 can maintain the airtightness of the battery cell 100 and prevent leakage of the internal electrolyte.

[0100] Hereinafter, a battery cell according to another embodiment of the present invention will be described. However, since the description of the battery cell 100 described above can be mostly applied to the battery cell according to this embodiment, the gas discharge guiding portion 450 inserted into the lead film 400 will be described centering on the differences from the battery cell 100.

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

[0102] Referring to FIGS. 3 and 11, in this embodiment, unlike FIG. 5, the gas discharge guiding portion 450' can be located on the electrode lead 300'. More specifically, no separate lead film 400' is located between the gas discharge guiding portion 450' and the electrode lead 300'. That is, the gas discharge guiding portion 450' is inserted into one surface of the lead film 400' adjacent to the electrode lead 300' and can be in contact with the electrode lead 300'. In other words, in this embodiment, after the gas discharge guiding portion 450' is attached or fixed on the electrode lead 300', the outer surface of the gas discharge guiding portion 450' can be covered with the lead film 400'.

[0103] By positioning the gas discharge guiding portion 450' adjacent to the electrode lead 300' in this way, the thickness of the lead film 400' covering the gas discharge guiding portion 450' is also relatively reduced, so there is an advantage that the manufacturing cost can be saved and the manufacturing process is easy.

[0104] Also, an adhesive layer 470' can be formed between the gas discharge guiding portion 450' and the electrode lead 300'. Here, the adhesive layer 470' can extend along the interface between the gas discharge guiding portion 450' and the electrode lead 300'. At this time, the adhesive layer 470' can be formed over the entire or a part of the interface between the gas discharge guiding portion 450' and the electrode lead 300'.

[0105] As an example, the adhesive layer 470' may be composed of an adhesive tape or an adhesive binder. However, it is not limited thereto, and any substance having an adhesive performance capable of fixing between the gas discharge guiding part 450' and the electrode lead 300' can be applied without limitation.

[0106] Thereby, the gas discharge guiding part 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 force between the gas discharge guiding part 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 also be further improved.

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

[0108] Referring to FIGS. 12 to 14, in the present embodiment, similarly to FIGS. 7 to 10, a gas discharge path may be formed at the interface between the gas discharge guiding part 450' and the lead film 400'. However, in the present embodiment, different from FIGS. 7 to 10, since the gas discharge guiding part 450' is in contact with the electrode lead 300' and the adhesive layer 470' is formed between the gas discharge guiding part 450' and the electrode lead 300', no gas discharge path is formed at the interface between the gas discharge guiding part 450' and the electrode lead 300'.

[0109] More specifically, in the present embodiment, the adhesive force between the gas discharge guiding part 450' and the lead film 400' is smaller than the adhesive force between the adhesive layer 470' and the gas discharge guiding part 450' and / or the adhesive force between the adhesive layer 470' and the electrode lead 300'.

[0110] More specifically, in the present embodiment, when the pressure inside the battery cell 100 rises, since the adhesive force at the interface between the gas discharge guiding portion 450' and the lead film 400' is relatively smaller than the adhesive force between the lead film 400' and other components, the portion of the lead film 400 that is not sealed by the first sealing portion 251 will move in the direction of the thick arrow in FIG. 12 even under a small internal pressure. Therefore, as shown in FIG. 13, at least a part of the interface between the gas discharge guiding portion 450' and the lead film 400' can be separated from each other by the internal pressure of the battery cell 100.

[0111] Furthermore, in the present embodiment, since the adhesive force at the interface between the gas discharge guiding portion 450' and the lead film 400' is smaller than the adhesive force between the gas discharge guiding portion 450' and the adhesive layer 470' and / or the adhesive force between the adhesive layer 470' and the electrode lead 300', it is possible to prevent the interface between the gas discharge guiding portion 450' and the electrode lead 300' from peeling when the internal pressure of the battery cell 100 increases.

[0112] That is, in the present embodiment, only the interface between the gas discharge guiding portion 450' and the lead film 400' peels off to form a gas discharge path. Therefore, while maintaining the gas discharge performance through the gas discharge path, the sealing strength of the battery cell 100 can be increased. Also, due to the high sealing strength, the vent pressure when the gas generated inside the battery cell 100 is discharged to the outside becomes higher, and the safety can be further improved.

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

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

[0115] Referring to FIGS. 15 to 17, the battery cell 10 according to the comparative example is the same as the battery cell 10 in FIGS. 1 and 2 except that it does not include the gas discharge guiding portion 45 as in the embodiment of the present invention. Hereinafter, the gas discharge guiding portion 45 will be mainly described.

[0116] Referring to FIGS. 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. Different from FIGS. 3 to 10, the width of the sealing portion 25 is formed to be constant regardless of the position of the sealing portion 25. As a result, all of the lead films 40 located on the gas discharge guiding portion 45 are sealed by the sealing portion 25.

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

[0118] In contrast, referring to FIGS. 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, different from 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, and 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 formed more easily and the gas discharge performance can be further improved.

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

[0120] The above-described battery module and the battery pack including the same can be applied to various devices. Such devices can be transportation means such as electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto, and the present invention is applicable to various devices that can use the battery module and the battery pack including the same, which also belongs to the scope of the rights of the present invention.

[0121] As described above in detail with respect to the preferred embodiments of the present invention, the scope of the rights of the present invention is not limited thereto, and it goes without saying that various modifications and improvements by those skilled in the art using the basic concept of the present invention claimed in the claims also belong to the scope of the rights of the present invention.

Explanation of Reference Numerals

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

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, The battery cell, wherein gas inside the battery case permeates through the lead film and is discharged to the outside of the battery case.

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 1 , wherein the first sealing portion is recessed with respect to the second sealing portion and has a pattern recessed outward with respect to an inner side of the sealing portion.

4. The battery cell according to claim 1 , wherein a receiving extension portion is located between the first sealing portion and the receiving portion.

5. The battery cell according to claim 4 , 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.

6. The battery cell according to claim 4 , wherein the lead film is peeled off from the gas discharge guide portion by gas pressure inside the battery case in the space between the lead film and the housing extension portion.

7. 5. The battery cell of claim 4, wherein a portion of the lead film that is not sealed by the first sealing portion is exposed, and the portion of the lead film that is not sealed by the first sealing portion is pressurized by the gas pressure inside the battery case, causing the interface between the lead film and the gas discharge guide portion to peel off, and the peeled portion of the lead film is located adjacent to the storage extension portion.

8. 2. 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. 10. The battery cell of claim 9, wherein the other end of the gas discharge guiding portion is located outside an outer surface of the sealing portion, and the gas that has flowed into the gas discharge guiding portion is discharged along a direction perpendicular to a protruding direction of the electrode lead at the lead film portion between the other end of the gas discharge guiding portion and the outer surface of the sealing portion.

11. The battery cell according to claim 1 , wherein a gas discharge path is formed at an interface between the gas discharge guide portion and the lead film.

12. The battery cell of claim 11 , 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.

13. The battery cell according to claim 11 , wherein the gas discharge path is a space in which at least a portion of an interface between the gas discharge guide portion and the lead film is separated from each other by gas pressure inside the battery case.

14. The battery cell according to claim 11 , wherein the gas discharge guide portion is a coating layer made of a liquid resin.

15. 12. The battery cell of claim 11, wherein the gas discharge guide further includes a getter material including at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca).

16. 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.

17. The battery cell of claim 16 , 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.

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

19. 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.

20. 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.

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

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