Battery cell and battery cell manufacturing apparatus for manufacturing the same

Abstract

To provide a battery cell with improved external emission of gas generated inside the battery cell while enhancing sealing strength and safety, and a battery cell manufacturing apparatus for manufacturing 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. The lead film includes a first stepped portion protruding in a direction opposite to the electrode lead, the sealing portion includes a second stepped portion enclosing an outer surface of the first stepped portion, and a gas discharge guiding unit is inserted in the first stepped portion.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery cell and a battery cell manufacturing apparatus for manufacturing the same. More specifically, the present invention relates to a battery cell having increased sealing strength and safety, and improved ability to discharge gas generated inside the battery cell to the outside, and a battery cell manufacturing apparatus for manufacturing the same. This application claims priority based on Korean Patent Application No. 10-2021-0088727 filed on July 6, 2021 and Korean Patent Application No. 10-2022-0081997 filed on July 4, 2022, and all of the contents disclosed in the specifications and drawings of the applications are incorporated into this application.

Background Art

[0002] As 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 divided 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 charging and discharging. It is divided into a jelly roll type in which a separator is interposed between a long sheet-type positive electrode and 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 gradually increasing in use 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 located 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 that can discharge 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, the 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 discharge ability of 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 enhanced sealing strength and safety and improved external discharge ability of the gas generated inside the battery cell, and a battery cell manufacturing apparatus for manufacturing the same.

[0009] The problem to be solved by the present invention is not limited to the above-described problems, 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 PROBLEMS

[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 a portion corresponding to the sealing portion at at least one of an upper portion and a lower portion of the electrode lead. The lead film includes a first stepped portion protruding in a direction opposite to the electrode lead side, the sealing portion includes a second stepped portion covering and enclosing an outer surface of the first stepped portion, and a gas discharge guiding portion is inserted into the first stepped portion.

[0011] The first step of the first stepped portion and the second step of the second stepped portion may each have a size corresponding to the height of the gas discharge guiding portion.

[0012] The first step and the second step may have the same size.

[0013] The gas discharge guiding portion may be located on a central portion of the electrode lead with reference to a width direction of the lead film.

[0014] The gas discharge guiding portion extends along a protruding direction of the electrode lead, and an end portion of the gas discharge guiding portion adjacent to the outside of the battery case may be covered and enclosed by the lead film.

[0015] An end portion of the gas discharge guiding portion adjacent to the inside of the battery case may be exposed inside the battery case. A gas discharge path may be formed at an interface between the gas discharge guiding portion and the lead film.

[0016] An adhesive force between the gas discharge guiding portion and the lead film may be smaller than at least one of an adhesive force between the lead film and the electrode lead and an adhesive force between the lead film and the sealing portion.

[0017] The gas discharge guiding part may be a film layer made of at least one of polyimide and polyethylene terephthalate.

[0018] The gas discharge guiding part may be a coating layer made of a liquid resin.

[0019] The gas discharge guiding part may further include a getter material containing at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca).

[0020] The thickness of the second step part may be formed uniformly.

[0021] The gas discharge guiding part is located on the electrode lead, and an adhesive layer may be formed between the gas discharge guiding part and the electrode lead.

[0022] The adhesive force between the gas discharge guiding part and the lead film may be smaller than the adhesive force between the adhesive layer and the gas discharge guiding part and the adhesive force between the adhesive layer and the electrode lead.

[0023] The adhesive layer may be made of an adhesive tape or an adhesive binder.

[0024] The gas permeability of the lead film may be 20 to 60 barrer at 60°C.

[0025] The amount of water penetration of the lead film may be 0.02 g to 0.2 g in 10 years at 25°C and 50% RH.

[0026] The gas permeability of the gas discharge guiding part may be 40 barrer or more at 60°C.

[0027] A battery cell manufacturing apparatus according to another aspect of the present invention manufactures the above-described battery cell and includes a sealing tool that seals the sealing portion, the electrode lead, and the lead film together. The sealing tool includes a third stepped portion recessed in a direction opposite to the sealing portion side. The third stepped portion covers the outer surface of the first stepped portion, and the second stepped portion is located between the third stepped portion and the outer surface of the first stepped portion.

[0028] The first step of the first stepped portion, the second step of the second stepped portion, and the third step of the third stepped portion may each have a size corresponding to the height of the gas discharge guiding portion.

[0029] The first step, the second step, and the third step may have the same size as each other.

Advantages of the Invention

[0030] According to an embodiment of the present invention, by providing a battery cell in which stepped portions are formed on a lead film and a sealing portion, respectively, and a battery cell manufacturing apparatus for manufacturing the same, the sealing strength and safety are enhanced, and the ability to discharge gas generated inside the battery cell to the outside can be improved.

[0031] Specifically, according to an embodiment of the present invention, a gas discharge path can be formed at the interface between the gas discharge guiding portion and the lead film, the manufacturing process is relatively easy, and the gas inside the battery cell can be effectively discharged outward.

[0032] According to another embodiment of the present invention, although the first stepped portion is formed on the lead film, the second stepped portion is also formed at a position corresponding to the first stepped portion on the sealing portion. Therefore, the sealing strength between the sealing portion and the lead film can be improved. Furthermore, due to the high sealing strength between the sealing portion and the lead film, the vent pressure when the gas generated inside the battery cell is discharged to the outside also increases, and the safety can be improved.

[0033] According to still other embodiments of the present invention, by adjusting the shape of the gas discharge guiding portion, it is possible to control the gas discharge performance of the gas discharge guiding portion and the durability and airtightness of the lead film. Further, if necessary, by changing the shape of the gas discharge guiding portion, the manufacturing process can be simplified and the cost can be reduced.

[0034] According to still other embodiments of the present invention, by setting the gas permeability and the amount of moisture penetration of the lead film within a predetermined range, it is more effective in preventing moisture penetration from the outside while discharging the gas generated inside the battery cell.

[0035] According to still other embodiments of the present invention, there is provided a battery cell manufacturing apparatus for manufacturing a battery cell in which a first stepped portion is formed on a lead film and a second stepped portion is formed at a position corresponding to the first stepped portion also in a sealing portion. According to such a battery cell manufacturing apparatus, since a battery cell can be manufactured without forming an excessive sealing portion on the sealing portion, it is possible to prevent a decrease in the sealing strength between the excessive sealing portion and the lead film when the excessive sealing portion is formed. By being able to maintain a high sealing strength between the sealing portion and the lead film, the vent pressure when the gas generated in the battery cell is discharged to the outside also increases, and it is possible to manufacture a battery cell with improved safety.

[0036] The effects of the present invention are not limited to the effects described above, and the 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

[0037]

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

Embodiments for Carrying Out the Invention

[0038] 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 below.

[0039] To clearly explain the present invention, parts not related to the explanation are omitted, and the same reference numerals will be given to the same or similar components throughout the specification.

[0040] In addition, the sizes and thicknesses of the illustrated components 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 exaggeratedly shown.

[0041] Also, throughout the specification, when a certain part "includes" a certain component, this does not exclude other components and means that other components may be further included, unless otherwise specified.

[0042] Also, throughout the specification, when it is a "plan view", this means the case when the target part is viewed from above, and when it is a "cross-sectional view", this means the case when the cross-section obtained by vertically cutting the target part is viewed from the side.

[0043] 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 of the battery cell, but it is not necessarily limited thereto, and the same or similar description may also be applicable to the other end of the battery cell.

[0044] FIG. 3 is a top view of a battery cell according to an embodiment of the present invention, and FIG. 4 is an enlarged view showing the two-dot chain line region in FIG. 3.

[0045] Referring to FIGS. 3 and 4, 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 electrically connected to an electrode tab 115 included in the electrode assembly 110 and protruding 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 be a substantially rectangular plate-shaped cell having a long side in the X-axis direction, a short side in the Y-axis direction, and the Z-axis direction being formed shorter than the lengths 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 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.

[0046] 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 contour, a barrier metal layer for preventing the passage of substances, and an inner resin layer for sealing.

[0047] The electrode assembly 110 may have a jelly roll type (winding type), a laminated type (stack type), or a composite type (laminated / folded type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0048] The electrode lead 300 is electrically connected to the electrode tab 115 included in the electrode assembly 110 and protrudes outside the battery case 200 through the sealing portion 250. Also, 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 thermal fusion or press fusion together with the sealing portion 250, and can improve the sealing performance between the sealing portion 250 and the electrode lead 300.

[0049] Referring to FIGS. 3 and 4, 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 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.

[0050] The lead film 400 may have a length 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 the side surface of the electrode lead 300 from being exposed to the outside.

[0051] FIG. 5 is a cross-sectional view taken along line B-B' of FIG. 4.

[0052] Referring to FIGS. 4 and 5, the lead film 400 includes a first stepped portion 400p protruding in the direction opposite to the electrode lead 300 side, and a gas discharge guiding portion 450 is inserted into the first stepped portion 400p.

[0053] Here, the first stepped portion 400p may mean a portion that protrudes in the direction opposite to the electrode lead 300 side with respect to the surface where the lead film 400 and the sealing portion 250 are in contact. More specifically, the first stepped portion 400p may mean a portion that protrudes in the direction opposite to the electrode lead 300 side at the position where the gas discharge guiding portion 450 is inserted. In other words, the first stepped portion 400p may mean a portion where a step is generated between the portion of the lead film 400 where the gas discharge guiding portion 450 is inserted and the portion where the gas discharge guiding portion 450 is not inserted.

[0054] Further, the sealing portion 250 includes a second stepped portion 250p that covers and wraps the outer surface of the first stepped portion 400p. Here, the second stepped portion 250p may mean a portion that protrudes along the protruding direction of the first stepped portion 400p with respect to the surface where the lead film 400 and the sealing portion 250 are in contact. More specifically, the second stepped portion 250p may mean a portion that protrudes along the protruding direction of the first stepped portion 400p at the position where the first stepped portion 400p is formed. In other words, the second stepped portion 250p may mean a portion where a step is generated between the portion of the sealing portion 250 where the first stepped portion 400p is formed and the portion where the first stepped portion 400p is not formed.

[0055] With the above configuration, in this embodiment, although the first stepped portion 400p is formed on the lead film 400, the second stepped portion 250p is also formed at the position corresponding to the first stepped portion 400p in the sealing portion 250. Therefore, the sealing strength between the sealing portion 250 and the lead film 400 can be improved. Furthermore, due to the high sealing strength between the sealing portion 250 and the lead film 400, the vent pressure when the gas generated inside the battery cell 100 is discharged to the outside also increases, and the safety can be improved.

[0056] In addition, in the lead film 400 and the sealing portion 250, although there is no limitation on the sizes of the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p, they may have sizes corresponding to the thickness D (height in the Z-axis direction) of the gas discharge guiding portion 450. More specifically, the first step d1 and the second step d2 may be the same as, larger than, or smaller than the thickness D of the gas discharge guiding portion 450, respectively. As an example, the first step d1 and the second step d2 may each have the same size as the thickness D of the gas discharge guiding portion 450. As another example, the first step d1 and the second step d2 may have sizes that are 50% to 150% of the thickness D of the gas discharge guiding portion 450.

[0057] Thus, in this embodiment, since the first step portion 400p on the lead film 400 and the second step portion 250p of the sealing portion 250 have sizes corresponding to the thickness D of the gas discharge guiding portion 450, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when the gas generated within the battery cell 100 is discharged to the outside are increased, and the safety can also be improved.

[0058] More desirably, the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p have the same size and may each be the same as the thickness D of the gas discharge guiding portion 450.

[0059] Thereby, in this embodiment, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when the gas generated within the battery cell 100 is discharged to the outside are further increased, and the safety can also be further improved.

[0060] On the other hand, when the second step d2 has a size larger than or smaller than the first step d1, unsealed portions or over-sealed portions may occur between the lead film 400 and the sealing portion 250, resulting in a decrease in the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when the gas generated within the battery cell 100 is discharged to the outside, and there is a risk of reducing the safety.

[0061] Further, in the sealing portion 250, the thickness of the second step portion 250p can be formed uniformly. More specifically, in the sealing portion 250, the second step portion 250p can cover the outer surface of the lead film 400 with the same thickness. In other words, in the sealing portion 250, the second step portion 250p can cover the outer surface of the first step portion 400p with the same thickness.

[0062] Thus, in this embodiment, although the first step portion 400p is formed on the lead film 400, the sealing portion 250 can cover the outer surface of the lead film 400 with a uniform thickness, and the sealing strength between the sealing portion 250 and the lead film 400 and the thickness change rate of the sealing portion 250 before and after sealing are maintained uniformly. That is, a portion where the sealing strength is relatively weak between the sealing portion 250 and the lead film 400 can be minimized, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside also increases, and the safety can be improved.

[0063] 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.

[0064] Referring to FIGS. 4 and 5, the gas discharge guiding portion 450 can be located on the electrode lead 300. More specifically, the gas discharge guiding portion 450 can be located on the central portion of the electrode lead 300 with reference to the width direction of the lead film 400. In other words, the first step portion 400p and the second step portion 250p are located on the central portion of the electrode lead 300 with reference to the width direction of the lead film 400, and the gas discharge guiding portion 450 can be inserted into the first step portion 400p.

[0065] Thus, in the lead film 400, since the gas discharge guiding portion 450 is located on the electrode lead 300, the gas discharge guiding portion 450 has a relatively large area, and the discharge amount of the gas discharged by the gas discharge guiding portion 450 can be effectively increased.

[0066] FIG. 6 is a cross-sectional view taken along the line A-A' of FIG. 3.

[0067] Referring to FIGS. 4 and 6, 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, the 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 outside the battery case 200.

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

[0069] Thus, in the lead film 400, the end portion 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 portion 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 in 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. 6, 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 can be discharged to the outside more easily.

[0071] Referring further to FIG. 6, based on the protruding direction of the electrode lead 300, the width W of the lead film 400 covering and wrapping 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] FIG. 7 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, the gas discharge guiding portion 450 can be rectangular, extending along the protruding direction of the electrode lead 300 as shown in FIG. 4. However, it is not limited thereto, and the gas discharge guiding portion 450 can have various shapes such as circular as shown in FIG. 7(a), elliptical as shown in FIG. 7(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 as shown in FIG. 7(c), and a second gas discharge guiding portion 450b extending in a direction perpendicular to the protruding direction of the electrode lead 300. In particular, the first gas discharge guiding portion 450a and the second gas discharge guiding portion 450b may be connected to each other. Here, as shown in FIG. 7(c), the second gas discharge guiding portion 450b is located outside the sealing portion 250 and inside the lead film 400 with respect to the sealing portion 250, or as shown in FIG. 7(d), it may be located inside the sealing portion 250 and outside the lead film 400 with respect to the sealing portion 250. Or, as shown in FIG. 7(e), the second gas discharge guiding portion 450b may be located on both the outside and the inside of the lead film 400 with respect to the sealing portion 250. However, the gas discharge guiding portion 450 is not limited to the above-described shape 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. Also, if necessary, the shape of the gas discharge guiding portion 450 can be changed 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 shown in FIG. 4. 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 portions 450 inserted into the lead film 400 in this way, the gas discharge performance of the gas discharge guiding portions 450 and the durability and airtightness of the lead film 400 can be controlled. Also, if necessary, the number of the gas discharge guiding portions 450 can be minimized to simplify the manufacturing process and reduce costs.

[0078] FIG. 8 is an enlarged view showing the two-dot chain line area in FIG. 6, and FIG. 9 is a view showing a gas discharge path formed at the interface between the lead film and the gas discharge guiding portion in FIG. 8. In FIG. 9, the gas movement path is indicated by a dotted arrow.

[0079] Referring to FIGS. 8 and 9, in the present embodiment, a gas discharge path can be formed at the interface between the gas discharge guiding portion 450 and the lead film 400. More specifically, as shown in FIG. 9, the gas discharge path may mean a space in which at least a part of the interface between the gas discharge guiding portion 450 and the lead film 400 is separated from each other by the pressure of the gas generated in the battery case 200. That is, as in the direction of the dotted arrow in FIG. 9, the gas discharge path may mean a path through which gas flows into a space separated from each other at the interface between the gas discharge guiding portion 450 and the lead film 400 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 and / 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 in 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 FIG. 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 peeled off from each other, the gas inside the battery cell 100 flows into the gas discharge path formed at the interface between the gas discharge guiding portion 450 and the lead film 400, the gas moves along the gas discharge path, and finally is discharged through the lead film 400. The gas flowing into the gas discharge path can be discharged toward the outside due to the pressure difference with the outside.

[0082] However, the gas discharge path includes not only the case where both the interface between the upper surface of the gas discharge guiding portion 450 and the lead film 400 and the interface between the lower surface of the gas discharge guiding portion 450 and the lead film 400 are separated as shown in FIG. 9, but also the case where either the interface between the upper surface of the gas discharge guiding portion 450 and the lead film 400 or the interface between the lower surface of the gas discharge guiding portion 450 and the lead film 400 is separated.

[0083] 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 or the material constituting the gas discharge guiding portion 450 is not limited thereto, and any form or material that can make the adhesive force between the gas discharge guiding portion 450 and the lead film 400 relatively lower than the adhesive force between the lead film 400 and other components may be included in this embodiment.

[0084] Thus, 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 6, based on 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, with reference to 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 the interference of 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 the gas, if the gas discharge path is completely covered by the sealing portion 250, the gas discharge will not be smooth. Therefore, as described above, providing a gap P between the outer surface of the sealing portion 250 and the other end of the gas discharge guiding portion 450 has the effect of smoothing the gas discharge.

[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 (SiO2), 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 thereto and may include all types of materials generally classified as getter materials.

[0090] Thus, in this embodiment, by further including a substance capable of absorbing or adsorbing moisture or hydrofluoric acid in the gas discharge guiding part 450, the gas discharge guiding part 450 can further minimize the penetration of moisture or hydrofluoric acid flowing from the outside of the battery cell 100 into the inside of the battery cell 100. In one embodiment of the present invention, the gas permeability of the gas discharge guiding part 450 may be 40 barrer or more at 60°C. For example, the carbon dioxide permeability of the gas discharge guiding part 450 may satisfy the above-described range.

[0091] For example, the gas discharge guiding part 450 may include at least one of a polyolefin-based, fluorine-based, and porous ceramic-based substance that satisfies the above-described gas permeability range. The polyolefin-based substance may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinylidene difluoride (PVDF). The fluorine-based substance may include one or more materials selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride.

[0092] 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 more effectively discharged.

[0093] In this specification, the gas permeability can be measured by ASTM F2476-20.

[0094] In one embodiment of the present invention, the water 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 water penetration amount of the lead film 400 satisfies the above-described range, it is possible to more effectively prevent the penetration of water flowing in from the lead film 400.

[0095] In one embodiment of the present invention, the lead film 400 has a gas permeability of 20 to 60 barrer at 60°C and a water penetration amount that may be 0.02 g to 0.2 g over 10 years at 25°C and 50% RH. When the gas permeability and the water penetration amount of the lead film 400 satisfy the above-described range, it is possible to more effectively prevent water penetration from the outside while discharging the gas generated inside the battery cell 100.

[0096] The water 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.

[0097] 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 include polyethylene, polypropylene, etc. that satisfy the above-described gas permeability and / or water penetration amount values.

[0098] 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.

[0099] 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.

[0100] FIG. 10 is a cross-sectional view taken along line B-B' of FIG. 4 in a battery cell according to another embodiment of the present invention.

[0101] Referring to FIG. 10, 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' can be inserted into the first step portion 400p' of the lead film 400' 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 by the lead film 400'.

[0102] Since the gas discharge guiding portion 450' is located 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.

[0103] 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 on the whole or a part of the interface between the gas discharge guiding portion 450' and the electrode lead 300'.

[0104] As an example, the adhesive layer 470' can 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 portion 450' and the electrode lead 300' can be applied without limitation.

[0105] As a result, 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', it is possible to prevent peeling due to an increase in the internal pressure of the battery cell 100, and the sealing strength of the battery cell 100 can also be further improved.

[0106] FIG. 11 is a cross-sectional view taken along line A-A' of FIG. 3 in a battery cell having the cross-section of FIG. 10. FIG. 12 is an enlarged view showing the two-dot chain line area of FIG. 11. FIG. 13 is a view showing a gas discharge path formed at the interface between the lead film and the gas discharge guiding part of FIG. 12. In FIG. 13, the movement path of the gas is indicated by dotted arrows.

[0107] Referring to FIGS. 11 to 13, in this embodiment, similar to FIGS. 6 to 9, a gas discharge path can be formed at the interface between the gas discharge guiding part 450' and the lead film 400'. However, in this embodiment, different from FIGS. 6 to 9, 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', a gas discharge path is not formed at the interface between the gas discharge guiding part 450' and the electrode lead 300'.

[0108] More specifically, in this 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'.

[0109] More specifically, in this embodiment, when the pressure inside the battery cell 100 increases, since the adhesive force at the interface between the gas discharge guiding part 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 part 450' and the lead film 400' can be separated from each other by the internal pressure of the battery cell 100 as shown in FIG. 13.

[0110] 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.

[0111] 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, it is possible to increase the sealing strength of the battery cell 100 while maintaining the gas discharge performance through the gas discharge path. In addition, due to the high sealing strength, the vent pressure when the gas generated inside the battery cell 100 is discharged to the outside also becomes higher, and the safety can be further improved.

[0112] Hereinafter, a battery cell manufacturing apparatus according to another embodiment of the present invention, and a battery cell manufactured thereby will be mainly described. In the case of the present embodiment, it will be described based on the embodiment according to FIGS. 3 to 9, but it can be similarly described in the case of the embodiment according to FIGS. 10 to 13.

[0113] FIG. 14 is a diagram showing a battery cell manufacturing apparatus according to another embodiment of the present invention, and a battery cell manufactured thereby.

[0114] Referring to FIG. 14, a battery cell manufacturing apparatus according to another embodiment of the present invention includes a sealing tool 1000 that manufactures a battery cell 100 and seals the sealing portion 250, the electrode lead 300, and the lead film 400 together. Here, the sealing tool 1000 can seal the sealing portion 250, the electrode lead 300, and the lead film 400 by thermal fusion or press fusion.

[0115] In addition, the sealing tool 1000 includes a third stepped portion 1000r recessed in a direction opposite to the sealing portion 250 side. The third stepped portion 1000r covers the outer surface of the first stepped portion 400p, and the second stepped portion 250p may be located between the third stepped portion 1000r and the outer surface of the first stepped portion 400p. More specifically, with respect to the sealing portion 250 that extends long as shown in Fig. 14(a), the third stepped portion 1000r of the sealing tool 1000 presses the sealing portion 250, so that the second stepped portion 250p can be formed between the first stepped portion 400p and the third stepped portion 1000r as shown in Fig. 14(b).

[0116] Here, the third stepped portion 1000r may mean a portion recessed in a direction opposite to the sealing portion 250 side with reference to the surface where the sealing tool 1000 and the sealing portion 250 are in contact. More specifically, with reference to the position where the first stepped portion 400p is formed in the lead film 400, the third stepped portion 1000r may mean a portion recessed in a direction opposite to the sealing portion 250 side. In other words, in the sealing tool 1000, the third stepped portion 1000r may mean a portion where a step occurs between the portion where the first stepped portion 400p is formed and the portion where the first stepped portion 400p is not formed.

[0117] With the above configuration, in this embodiment, although the first stepped portion 400p is formed on the lead film 400, the third stepped portion 1000r of the sealing tool 1000 can form the second stepped portion 250p at a position corresponding to the first stepped portion 400p, and the sealing strength between the sealing portion 250 and the lead film 400 can be improved. Furthermore, due to the high sealing strength between the sealing portion 250 and the lead film 400, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside also increases, and the safety can be improved.

[0118] Referring further to FIGS. 5 and 14, in the sealing tool 1000, the third step d3 of the third step portion 1000r may have a size corresponding to the thickness D of the gas discharge guiding portion 450 together with the first step d1 and the second step d2. More specifically, the size of the third step d3 may be the same as, larger than, or smaller than that of the gas discharge guiding portion 450. As an example, the first step d1 to the third step d3 may have the same size as each other. As another example, the third step d3 may have a size of 50% to 150% with respect to the thickness D of the gas discharge guiding portion 450.

[0119] Thus, in this embodiment, since the third step portion 1000r of the sealing tool 1000 has a size corresponding to the thickness D of the gas discharge guiding portion 450, it may have the same size as the first step portion 400p, and the second step portion 250p of the sealing portion 250 may also have a size similar to that of the first step portion 400p. That is, since the thickness of the second step portion 250p of the sealing portion 250 can be uniformly formed along the outer surface of the first step portion 400p, the sealing strength between the sealing portion 250 and the lead film 400 and the thickness change rate of the sealing portion 250 before and after sealing can be maintained uniformly. In addition, the sealing strength against the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside are also increased, and the safety can be improved.

[0120] More preferably, the first step d1 to the third step d3 may have the same size and may be the same as the thickness D of the gas discharge guiding portion 450 respectively.

[0121] Thus, in this embodiment, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside are also higher, and the safety can be further improved.

[0122] In contrast, when the third step d3 is larger or smaller than the first step d1, the second step d2 of the sealing portion 250 may not be formed with a uniform thickness. In particular, when the sealing portion 250 is pressed at an excessively high pressure and the thickness becomes thin, or when the sealing portion 250 is pressed at a pressure that is too low and an unsealed region may occur, the sealing strength between the sealing portion 250 and the lead film 400 and the vent pressure when the gas generated inside the battery cell 100 is discharged to the outside may decrease, which may also reduce the safety. FIG. 15 is a diagram showing a battery cell manufacturing apparatus according to a comparative example and a battery cell manufactured thereby.

[0123] Referring to FIG. 15, the battery cell manufacturing apparatus according to the comparative example is the same as the above-described battery cell manufacturing apparatus 1000, except that the sealing tool 1001 does not include the third step portion 1000r.

[0124] Referring to FIG. 15, in the battery cell manufacturing apparatus according to the comparative example, when the third step portion 1000r is not formed at a position corresponding to the first step portion 400p on the sealing tool 1001, an excessive sealing portion 250a may be formed in the sealing portion 250 as shown in FIG. 15(b).

[0125] More specifically, as shown in FIG. 15(a), although the first step portion 400p is formed on the lead film 400, the sealing tool 1001 has steps with the same overall height. At this time, the sealing tool 1001 applies a higher pressure to the portion of the sealing portion 250 facing the portion protruding by the first step portion 400p. As a result, as shown in FIG. 15(b), a relatively thin excessive sealing portion 250a may be formed in the portion of the sealing portion 250 facing the first step portion 400p.

[0126] As a result, unlike the battery cell manufacturing apparatus according to the comparative example, the sealing tool 1001 having the same height step that does not consider the height protruding due to the first step portion 400p formed on the lead film 400 forms an excessive sealing portion 250a on the sealing portion 250, and the sealing strength between the excessive sealing portion 250a and the lead film 400 decreases. Further, due to the weak sealing strength between the excessive sealing portion 250a and the lead film 400, the vent pressure when the gas generated in the battery cell is discharged to the outside becomes low, and there is a risk of reducing the safety.

[0127] In contrast, in the case of the battery cell manufacturing apparatus according to the present embodiment, by including the third step portion 1000r that takes into account the height by which the sealing tool 1000 protrudes due to the first step portion 400p formed on the lead film 400, an excessive sealing portion 250a as shown in FIG. 15(b) is not formed on the sealing portion 250, and the sealing strength and safety between the sealing portion 250 and the lead film 400 can be improved.

[0128] A battery module according to another embodiment of the present invention includes the battery cell described above. 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.

[0129] The battery module and the battery pack including the same described above 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 rights of the present invention.

[0130] As described above, the preferred embodiments of the present invention have been described in detail, but the scope of 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 rights of the present invention.

Explanation of Reference Numerals

[0131] 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 1000: Battery cell manufacturing apparatus

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, the lead film includes a first step portion protruding in a direction opposite to the electrode lead side, The sealing portion includes a second step portion that covers an outer surface of the first step portion, A battery cell having a gas discharge guide portion inserted into the first step portion, A battery cell, wherein gas generated inside the battery cell passes through the lead film and is discharged to the outside.

2. The battery cell according to claim 1 , wherein the first step of the first step portion and the second step of the second step portion each have a size corresponding to a height of the gas discharge guide portion.

3. The battery cell according to claim 2 , wherein the first step and the second step have the same size.

4. the first step portion is a step provided between a portion where the gas discharge guiding portion is inserted and a portion where the gas discharge guiding portion is not inserted, The battery cell according to claim 1 , wherein the second step portion is a step provided between a portion where the first step portion is formed and a portion where the first step portion is not formed.

5. 5. 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.

6. The battery cell according to claim 5 , 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.

7. 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.

8. The battery cell of claim 7 , 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 lead film and an electrode lead and an adhesive strength between the lead film and the sealing portion.

9. The battery cell according to claim 8 , wherein the gas discharge guide portion is a film layer made of at least one of polyimide and polyethylene terephthalate.

10. The battery cell according to claim 8 , wherein the gas discharge guide portion is a coating layer made of a liquid resin.

11. The gas exhaust guide portion is made of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO ２ 9. The battery cell of claim 8, further comprising a getter material comprising at least one of: barium oxide (BaO), barium (Ba), and calcium (Ca).

12. The battery cell according to claim 1 , wherein the second step portion has a uniform thickness.

13. 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.

14. The battery cell of claim 13 , 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.

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

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

17. 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.

18. 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.

19. A battery cell manufacturing apparatus for manufacturing the battery cell according to claim 1, a sealing tool for sealing the sealing part, the electrode lead and the lead film together; The sealing tool includes a third step portion recessed in a direction opposite to the sealing portion, the third step portion covers and surrounds an outer surface of the first step portion, and the second step portion is located between the third step portion and the outer surface of the first step portion.

20. 20. The battery cell manufacturing apparatus of claim 19, wherein a first step of the first step portion, a second step of the second step portion, and a third step of the third step portion each have a size corresponding to a height of the gas discharge guiding portion.

21. The battery cell manufacturing apparatus of claim 20 , wherein the first step, the second step, and the third step have the same size.

Images