Sealing device and secondary battery manufactured thereby

Abstract

According to an embodiment of the present invention, the sealing device may comprise a lead film surrounding a lead metal, and a sealing block provided to seal a pouch surrounding the lead film. The sealing block may include a first sealing surface provided to seal a central portion of the lead film overlapping the lead metal. The first sealing surface may include a center sealing surface and side sealing surfaces located on both sides of the center sealing surface and formed to have a height difference from the center sealing surface. The side sealing surfaces may be provided with sealing protrusions which protrude to a predetermined thickness in the direction in which the sealing block is pressed so as to prevent the lead film from inadvertently moving in the width direction of the sealing surface.

Description

Sealing device and secondary battery manufactured thereby

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0169882, filed November 29, 2023, and Korean Patent Application No. 10-2024-0111492, filed August 20, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a sealing device and a secondary battery manufactured thereby, and more specifically, to a sealing device for sealing a pouch, which is an outer material, and a pouch-type secondary battery manufactured thereby.

[0005] Secondary batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they have the primary advantage of dramatically reducing the use of fossil fuels, but also because they produce no byproducts from energy use.

[0006] In the manufacturing process of pouch-type secondary batteries, the lead film surrounding the lead metal is thermally bonded to the packaging material, the pouch, by a heating block or heating jig, which is a medium that provides heat and pressure. The inner adhesive layer of the pouch (e.g., a polypropylene layer), which exists in the form of a thin film, is melted by the applied heat, thereby increasing its freedom of flow, and then hardens through an appropriate cooling process to form the bond.

[0007] At this time, the adhesive layer that becomes fluid due to the applied heat and pressure usually becomes thinner than the state before bonding, and is pushed out in both lateral directions due to the essential characteristics of the applied pressure and fluid state. Due to this pushing (leakage) phenomenon, there is a problem that a sharp part is created by digging in a V shape in the heat-sealed adhesive layer itself, or an unequal wave shape is formed in the heat-sealed adhesive layer, which affects the durability and quality of the pouch-type secondary battery.

[0008] The background technology described above is something that the inventor possessed or acquired in the process of deriving the disclosure of the present application, and cannot necessarily be said to be a publicly known technology disclosed to the general public prior to the present application.

[0009] The present invention has been devised to solve the above problems, and a task to be solved by the present invention is to provide a sealing device capable of reducing the volume of a gap formed between a lead film and a pouch.

[0010] Another problem to be solved by the present invention is to provide a sealing device that can prevent a phenomenon in which a lead film covering a lead metal flows in the inside-outside direction of a pouch during sealing.

[0011] Another problem that the present invention seeks to solve is to provide a secondary battery having high quality by being manufactured by the sealing device.

[0012] A sealing device according to an embodiment of the present invention may include a sealing block provided to seal a lead film that wraps a lead metal and a pouch that surrounds the lead film. The sealing block may include a first sealing surface provided to seal a central portion of the lead film that overlaps the lead metal. The first sealing surface may include a center sealing surface; and side sealing surfaces that are located on both sides of the center sealing surface and are formed with a step from the center sealing surface. A sealing protrusion that protrudes with a predetermined thickness in a pressing direction of the sealing block may be provided on the side sealing surface to prevent the lead film from flowing in the width direction of the sealing surface.

[0013] The above side sealing surface may extend from an end of the above center sealing surface and may be provided with a step in the pressing direction from the above center sealing surface.

[0014] The above sealing block may further include a second sealing surface that is provided at a step from the first sealing surface to seal both ends of the lead film and the pouch.

[0015] The center sealing surface, the side sealing surface, and the second sealing surface may be sequentially provided in steps in the pressing direction.

[0016] The above side sealing surface can overlap with the widthwise end area of ​​the lead metal.

[0017] Between the side sealing surface and the second sealing surface, an inclined portion extending obliquely between one end of the side sealing surface and one end of the second sealing surface may be provided.

[0018] The above sealing protrusion may have a shape extending along a length direction perpendicular to the width direction of the side sealing surface.

[0019] The above sealing protrusions may be provided in multiple numbers at a predetermined interval in the width direction of the side sealing surface.

[0020] The above sealing protrusion can be formed on the width-wise edge of the side sealing surface.

[0021] The above sealing protrusion may include a first sealing protrusion formed on one width-wise edge of the side sealing surface, and a second sealing protrusion formed on the other width-wise edge of the side sealing surface.

[0022] The above sealing projection may be provided to extend beyond the side sealing surface to the second sealing surface.

[0023] The above sealing blocks may be provided as a pair, facing each other in the pressing direction.

[0024] A secondary battery according to an embodiment of the present invention may include a pouch including a housing for accommodating an electrode assembly and a sealing portion positioned around the housing portion; a lead metal connected to the electrode assembly and protruding outward from the sealing portion; and a lead film surrounding the lead metal and sealed with the sealing portion. The sealing portion may include a first region that is sealed with the pouch and the lead film and overlaps with the lead metal. The first region may include a center region; and side regions that are positioned on both sides of the center region and formed with a step from the center region. A pressed portion may be formed in the side region and extending in the longitudinal direction of the side region.

[0025] The above pressing portions may be provided in a pair extending parallel to each other at a predetermined interval in the width direction of the side region.

[0026] The above pressing portion may be formed on both edges in the width direction of the side area.

[0027] The above sealing portion may further include a second region that is stepped from the first region and seals both ends of the lead film and the pouch.

[0028] With respect to the thickness direction of the above sealing portion, the center region, the side region, and the second region may be sequentially provided in steps.

[0029] The above sealing portion may further include an inclined region formed between the side region and the second region and extending obliquely between one end of the side sealing surface and one end of the second sealing surface.

[0030] The above pressing portion may extend beyond the side region to the second region.

[0031] The above center region, side region and pressing portion may be located on both sides of the sealing portion.

[0032] According to a preferred embodiment of the present invention, the size of the gap formed between the lead film and the pouch can be reduced. As a result, the durability and quality of the pouch-type secondary battery can be improved.

[0033] Additionally, the lead film surrounding the lead metal can be prevented from flowing in the inward-outward direction of the pouch during sealing. This can improve the durability and quality of the pouch-type secondary battery.

[0034] In addition, the configurations according to the embodiments of the present invention may include effects that can be easily predicted by those skilled in the art.

[0035] Figure 1 is a perspective view of a pouch-type secondary battery.

[0036] Figure 2 is a perspective view of a sealing block of a sealing device according to a comparative example of the present invention.

[0037] Figure 3 is an enlarged view of part B shown in Figure 2.

[0038] FIG. 4 is a cross-sectional view corresponding to I-I' of FIG. 1 of a secondary battery manufactured by a sealing device according to a comparative example of the present invention.

[0039] Fig. 5 is a plan view showing an enlarged view of the sealing portion of a pouch formed by a sealing device according to a comparative example of the present invention around a lead film.

[0040] Figure 6 is a cross-sectional view of II-II' of Figure 5.

[0041] Figure 7 is a drawing showing a phenomenon in which the lead film protrudes in the width direction of the sealing surface during the sealing process.

[0042] Figure 8 is a perspective view of a sealing block of a sealing device according to Example 1 of the present invention.

[0043] Figure 9 is an enlarged view of part C shown in Figure 8.

[0044] FIG. 10 is a cross-sectional view corresponding to I-I' of FIG. 1 of a secondary battery manufactured by a sealing device according to Example 1 of the present invention.

[0045] Fig. 11 is an enlarged plan view of the sealing portion of a pouch formed by a sealing device according to Example 1 of the present invention, around a lead film.

[0046] Fig. 12 is a cross-sectional view of III-III' of Fig. 11.

[0047] Fig. 13 is an enlarged plan view of the sealing portion of a pouch formed by a sealing device according to Example 2 of the present invention, around a lead film.

[0048] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. The following description is one of several aspects of the embodiments, and in describing one embodiment, detailed descriptions of well-known functions or configurations will be omitted to clarify the gist of the present invention.

[0049] In this specification, when adding reference signs to components in each drawing, the same or similar reference signs are attached to identical or similar components throughout the specification. Components included in one embodiment and components that have common functions will be described using the same names in other embodiments. Terms or words used in this specification and the claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that are consistent with the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of the term to best explain his or her invention.

[0050] Furthermore, the present invention is not limited to the embodiments described above, and those skilled in the art will readily appreciate that various modifications and variations can be made based on this disclosure. Therefore, the spirit of the present invention should not be construed as limited to the embodiments described above, and all variations equivalent to or equivalent to the claims, as well as the scope of the claims, are deemed to fall within the scope of the present invention.

[0051] Figure 1 is a perspective view of a pouch-type secondary battery.

[0052] A pouch-type secondary battery may include a pouch (10) as an outer material. More specifically, the pouch (10) may include a receiving portion (11) that accommodates an electrode assembly, and a sealing portion (12) positioned around the receiving portion (11). The electrode assembly is formed by alternately interposing electrodes and separators, and its configuration and function are well known in the art, so a description thereof will be omitted.

[0053] The pouch (10) can be manufactured by forming a laminate sheet, and the laminate sheet can include a first resin layer forming an inner layer of the pouch (10), a second resin layer forming an outer layer of the pouch (10), and a metal layer positioned between the first resin layer and the second resin layer. For example, the first resin layer can be composed of polypropylene (PP), the second resin layer can be composed of polyethylene terephthalate (PET), and the metal layer can be composed of aluminum (AL).

[0054] The storage portion (11) can be formed by sinking the laminate sheet into a cup shape. The sealing portion (12) can be formed by sealing the pouches (10) together in an area located around the periphery of the storage portion (11) while the electrode assembly is accommodated in the storage portion (11).

[0055] A pouch-type secondary battery may include a lead metal (20) that is connected to an electrode assembly and protrudes outward from a sealing portion (12), and a lead film (30) that surrounds the lead metal (20) and is sealed with the sealing portion (12).

[0056] The lead metal (20) can be connected to the electrode of the electrode assembly and can act as a current passage. The lead metal (20) can be provided in a pair connected to the positive and negative electrodes. As shown in Fig. 1, the pair of lead metals (20) can protrude in opposite directions from the sealing portion (12). However, this is not limited thereto, and the pair of lead metals can also protrude in the same direction and in parallel.

[0057] The lead film (30) may surround a portion of the lead metal (20). The lead film (30) may insulate the lead metal (20) and the pouch (10). The lead film (30) may have an insulating material. The lead film (30) may be sealed with the inner layer of the pouch (10) when the sealing portion (12) is formed.

[0058] FIG. 2 is a perspective view of a sealing block of a sealing device according to a comparative example of the present invention, FIG. 3 is an enlarged view of part B shown in FIG. 2, FIG. 4 is a cross-sectional view corresponding to I-I' of FIG. 1 of a secondary battery manufactured by a sealing device according to a comparative example of the present invention, FIG. 5 is a plan view enlarged around a lead film of a sealing portion of a pouch formed by a sealing device according to a comparative example of the present invention, FIG. 6 is a cross-sectional view corresponding to II-II' of FIG. 5, and FIG. 7 is a drawing showing a phenomenon in which a lead film protrudes in the width direction of a sealing surface during a sealing process.

[0059] A sealing block (100) of a sealing device according to a comparative example of the present invention may be provided to seal a lead film (30) and a pouch (10). The sealing block (100) may pressurize and heat the lead film (30) and the pouch (10) surrounding it, thereby thermally fusing the pouch (10) and the lead film (30). The sealing blocks (100) may be provided as a pair on both sides of the lead film (30) and the pouch (10).

[0060] The sealing block (100) may include a plurality of sealing surfaces (110, 120, 140). The sealing surfaces (110, 120, 140) may be provided to contact a pouch (10) surrounding a lead film (30) to pressurize the pouch (10) and transfer heat to the pouch (10). The sealing surfaces (110, 120, 140) may include a first sealing surface (110), a second sealing surface (120), and a third sealing surface (140).

[0061] The first sealing surface (110) may be provided to seal the central portion of the lead film (30) overlapping the lead metal (20). More specifically, the first sealing surface (110) may seal the central portion of the lead film (30) and the inner layer of the pouch (10) to each other.

[0062] The second sealing surface (120) may be provided to seal the edge portion of the lead film (30). More specifically, the second sealing surface (120) may seal the edge portion of the lead film (30) that does not overlap with the lead metal (20) with the inner layer of the pouch (10). The second sealing surface (120) may be provided on the outer side of both ends of the first sealing surface (110), and may be formed to be stepped from the first sealing surface (110) with respect to the pressing direction (parallel to the z-axis) of the sealing block (100).

[0063] The third sealing surface (140) may be provided on the outer side of the second sealing surface (120). The third sealing surface (140) may seal the inner layers of the pouch (10) by pressurizing and heating the pouch (10).

[0064] A void (S) may be generated inside the pouch (10). Specifically, the void (S) may be generated between the pouch (10) and the lead film (30). The void (S) may be generated at a location corresponding to the connection portion between the first sealing surface (110) and the second sealing surface (120).

[0065] When the lead film (30) is melted during the sealing process and flows sufficiently in the longitudinal direction (parallel to the x-axis) of the sealing surface (110, 120), the volume of the void (S) can be reduced by filling the void (S) with the molten lead film (30). The longitudinal direction (parallel to the x-axis) of the sealing surface (110, 120) can be parallel to the width direction of the lead metal (20). In addition, the longitudinal direction (parallel to the x-axis) of the sealing surface (110, 120) can be parallel to the longitudinal direction of the lead film (30).

[0066] However, in the case of the sealing block (100) according to the comparative example, since the first sealing surface (110) has a flat, uncurved shape, the longitudinal direction (parallel to the x-axis) flow of the lead film (30) may not sufficiently occur. In this case, the volume of the gap (S) is maintained large, and the corresponding part may cause a gap between the pouch (10) and the lead film (30), which may lead to a deterioration in the quality of the secondary battery.

[0067] Referring to Fig. 7, it is possible to confirm the phenomenon of lead film (30) leaking that occurs during the process of sealing the pouch (10) and the lead film (30) by the sealing block (100). The lead film (30) can be pressed by the sealing block (100) on both sides in the thickness direction, and can protrude (P) in the width direction (parallel to the y-axis) of the lead film (30) due to the pressure applied from both directions.

[0068] In this case, when the lead film (30) protrudes in the width direction (parallel to the y-axis), the surface of the pouch (10) surrounding the lead film (30) may be damaged or wrinkled, and further, a problem may arise in which a gap is created between the pouch (10) and the lead film (30).

[0069] Referring to the drawings below, a sealing device and a secondary battery sealed thereby according to embodiments of the present invention for solving such problems will be described.

[0070] Example 1

[0071] Fig. 8 is a perspective view of a sealing block of a sealing device according to Example 1 of the present invention, and Fig. 9 is an enlarged view of part C shown in Fig. 8.

[0072] The sealing block (200) of the sealing device according to Embodiment 1 of the present invention can be provided to seal the lead film (30) and the pouch (10). That is, the sealing block (200) can form a sealing portion (12) of a pouch-type secondary battery. The sealing block (200) can heat-fuse the inner layer of the pouch (10) and the lead film (30) by applying pressure and heating.

[0073] The sealing blocks (200) may be provided as a pair, facing each other in the pressing direction (parallel to the z-axis). That is, a pair of sealing blocks (200) may face each other with the secondary battery interposed therebetween.

[0074] The sealing block (200) may be arranged to contact the pouch (10) to pressurize the pouch (10) and transfer heat to the pouch (10).

[0075] The sealing block (200) may include a first sealing surface (210) provided to seal a central portion of a lead film (30) overlapping with a lead metal (20). The first sealing surface (210) may seal the central portion of the lead film (30) and the pouch (10) by applying pressure and heating.

[0076] The sealing block (200) may further include a second sealing surface (220) that seals both ends of the lead film (30) and the pouch (10). The second sealing surface (220) may be provided with a step with respect to the first sealing surface (210).

[0077] The second sealing surface (220) may be provided to seal both ends of the lead film (30). Here, the ends of the lead film (30) may be portions that do not overlap with the lead metal (20). The second sealing surface (220) may be provided on the outer side of both ends of the first sealing surface (210). The second sealing surface (220) may be formed with a step so as to protrude further than the first sealing surface (210) with respect to the pressing direction of the sealing block (200) (parallel to the z-axis). An inclined portion (250) may be formed between the second sealing surface (220) and the first sealing surface (210) so as to be inclined due to the step. The inclined portion (250) may connect the first sealing surface (210) and the second sealing surface (220).

[0078] The sealing block (200) may further include a third sealing surface (240) that seals the inner layers of the pouch (10). The third sealing surface (240) may be provided with a step with respect to the second sealing surface (220).

[0079] The third sealing surface (240) is provided on the outer side of the second sealing surface (220), and can seal the pouches (10) by pressurizing and heating them. The third sealing surface (240) can be formed to protrude more than the second sealing surface (220) with respect to the pressing direction of the sealing block (200) (parallel to the z-axis). Accordingly, the third sealing surface (240), the second sealing surface (220), and the first sealing surface (210) can be sequentially provided in steps.

[0080] The first sealing surface (210) may include a center sealing surface (211) and a side sealing surface (212).

[0081] The center sealing surface (211) may be an area including the central portion of the first sealing surface (210), and the side sealing surfaces (212) may be areas including both ends of the first sealing surface (210).

[0082] The side sealing surface (212) may be formed to be stepped from the center sealing surface (211). More specifically, with respect to the pressing direction of the sealing block (200) (parallel to the z-axis), the side sealing surface (212) may be formed to be stepped so as to protrude further than the center sealing surface (211).

[0083] The side sealing surface (212) extends from the end of the center sealing surface (211), but can be formed to be stepped from the center sealing surface (211).

[0084] The side sealing surface (212) may be formed between the center sealing surface (211) and the second sealing surface (220). The side sealing surface (212) may also be formed to be stepped from the second sealing surface (220). In other words, the side sealing surface (212) may be formed to be stepped from both the center sealing surface (211) and the second sealing surface (220). That is, the center sealing surface (211), the side sealing surface (212), and the second sealing surface (220) may be formed to be stepped in the pressing direction (parallel to the z-axis) in that order.

[0085] By adopting the configuration of this side sealing surface (212), it is possible to reduce the size of the gap (S) and improve the sealing quality by inducing flow in the longitudinal direction (parallel to the x-axis) of the lead film (30) during the sealing process.

[0086] Meanwhile, the sealing block (200) may include a sealing protrusion (230). The sealing protrusion (230) may induce the molten lead film (30) to flow in the longitudinal direction (parallel to the x-axis) of the lead film (30). In addition, the sealing protrusion (230) may prevent the molten lead film (30) from flowing in the width direction (parallel to the y-axis) of the lead film (30). The sealing protrusion (230) may be formed to protrude from the first sealing surface (210) in the pressing direction (parallel to the z-axis) of the sealing block (200).

[0087] Specifically, the sealing protrusion (230) may be provided on the side sealing surface (212). The sealing protrusion (230) may be formed to protrude from the side sealing surface (212). The sealing protrusion (230) may have a shape that extends in the longitudinal direction of the side sealing surface (212). In other words, the sealing protrusion (230) may be formed in the shape of a bar having a rectangular shape.

[0088] The sealing protrusions (230) may be provided in multiple pieces. For example, the sealing protrusions (230) may be formed as a pair. In this case, the sealing protrusions (230) may include a first sealing protrusion (231) and a second sealing protrusion (232) that forms a predetermined distance from the first sealing protrusion (231) in the width direction of the side sealing surface (212). The first sealing protrusion (231) and the second sealing protrusion (232) may be formed parallel to each other in the width direction of the side sealing surface (212).

[0089] The first sealing protrusion (231) and the second sealing protrusion (232) may be positioned on both width-wise edges of the side sealing surface (212), respectively. The first sealing protrusion (231) may be positioned on the inner edge of the side sealing surface (212), and the second sealing protrusion (232) may be positioned on the outer edge of the side sealing surface (212).

[0090] The first sealing protrusion (231) and the second sealing protrusion (232) may be formed with the same width and length. The height at which the first sealing protrusion (231) and the second sealing protrusion (232) protrude from the side sealing surface (212) may also be the same.

[0091] The sealing protrusion (230) may extend in the longitudinal direction of the side sealing surface (212). More specifically, the sealing protrusion (230) may extend between the center sealing surface (211) and the inclined portion (250).

[0092] By employing the configuration of the sealing protrusion (230), when sealing the lead film (30) and the pouch (10) by the sealing block (200), the molten lead film (30) can be prevented from flowing out in the width direction (parallel to the y-axis) of the lead film (30). The width direction (parallel to the y-axis) of the lead film (30) can be parallel to the length direction of the lead metal (20), i.e., the inside-outside direction of the pouch (10). In addition, the width direction (parallel to the y-axis) of the lead film (30) can be parallel to the width direction of the side sealing surface (212).

[0093] FIG. 10 is a cross-sectional view corresponding to I-I' of FIG. 1 of a secondary battery manufactured by a sealing device according to Example 1 of the present invention.

[0094] A secondary battery manufactured by a sealing device according to the present invention also falls within the scope of the present invention.

[0095] Referring to FIGS. 9 and 10, the first sealing surface (210) of the sealing device can seal the central portion of the lead film (30) overlapping the lead metal (20) and the pouch (10) to each other. Accordingly, the sealing portion (12) of the pouch (10) can include a first region (13) that is sealed with the pouch (10) and the lead film (30) and overlaps with the lead metal (20). The first region (13) can be a portion formed by being pressed by the first sealing surface (210).

[0096] The second sealing surface (220) of the sealing device can seal both ends of the lead film (30) that do not overlap with the lead metal (20) and the pouch (10). Therefore, the sealing portion (12) of the pouch (10) can include a second region (14) where both ends of the lead film (30) and the pouch (10) are sealed. The second region (14) can be a portion formed by being pressed by the second sealing surface (220). Since the first sealing surface (210) and the second sealing surface (220) of the sealing device are formed to be stepped from each other, the first region (13) and the second region (14) of the pouch (10) can be formed to be stepped from each other.

[0097] The first sealing surface (210) of the sealing device may include a center sealing surface (211) and a side sealing surface (212). The side sealing surface (212) may be formed to protrude further from the center sealing surface (211) in the pressing direction (parallel to the z-axis) of the sealing block (200). The center sealing surface (211), the side sealing surface (212), and the second sealing surface (220) may be sequentially provided to be stepped in the pressing direction (parallel to the z-axis) of the sealing block (200). The side sealing surface (212) may overlap with the widthwise edge area of ​​the lead metal (20). A gap (S) may be formed between the lead film (30) and the pouch (20). The gap (S) may be located in an area corresponding to the inclined portion (250). That is, the slope (250) can face the gap (S).

[0098] The side sealing surface (212) is formed to protrude more than the center sealing surface (211) in the pressing direction (parallel to the z-axis), thereby applying a relatively large pressure to the lead film (30) in the area overlapping the side sealing surface (212). More specifically, a greater pressure can be applied to the lead film (30) in the area overlapping the side sealing surface (212) in the pressing direction (parallel to the z-axis) than to the lead film (30) in the area overlapping the center sealing surface (211). As a result, the flow of the molten lead film (30) in the longitudinal direction (parallel to the x-axis) of the side sealing surface (212) can be promoted. That is, due to the side sealing surface (212), the molten lead film (30) can flow in the longitudinal direction (parallel to the x-axis) of the side sealing surface (212) and be introduced into the gap (S). Therefore, the volume of the void (S) can be reduced.

[0099] Since the first sealing surface (210) includes the center sealing surface (211) and the side sealing surface (212), the first region (13) of the sealing portion (12) of the pouch (10) may include a center region (13A) and a side region (13B). The center region (13A) may be a region formed by being pressed by the center sealing surface (211), and the side region (13B) may be a region formed by being pressed by the side sealing surface (212).

[0100] The center region (13A) may overlap the central portion of the lead metal (20), and the side regions (13B) may overlap the widthwise edges of the lead metal (20). The side regions (13B) may be located on both sides of the center region (13A). The side regions (13B) may be formed to be stepped with respect to the center region (13A). More specifically, the side regions (13B) may be formed to be stepped toward the lead film (30) with respect to the center region (13A). That is, since the side region (13B) is pressed more strongly than the center region (13A), the molten lead film (30) may be further introduced into the void (S), and the volume of the void (S) may be reduced.

[0101] In addition, the second region (14) may be formed in a stepwise manner with respect to the side region (13B). More specifically, the second region (14) may be formed in a stepwise manner toward the lead film (30) with respect to the side region (13B). That is, with respect to the thickness direction of the sealing portion (12), the center region (13A), the side region (13B), and the second region (14) may be sequentially formed in a stepwise manner.

[0102] The sealing portion (12) of the pouch (10) may further include an inclined region (16) formed between the side region (13B) and the second region (14). The inclined region (16) may be a region formed by being pressed by the inclined portion (250) of the sealing block (200). The inclined region (16) may extend obliquely between one end of the side region (13B) and one end of the second region (14).

[0103] The sealing portion (12) of the pouch (10) may further include a third region (17) (see FIG. 11) in which the inner layers of the pouch (10) are sealed. The third region (17) may be a region formed by being pressed by the third sealing surface (240). Since the second sealing surface (220) and the third sealing surface (240) of the sealing device are formed to be stepped from each other, the second region (14) and the third region (17) of the pouch (10) may be formed to be stepped from each other. More specifically, the third region (17) may be formed to be stepped toward the inner layer of the pouch (10) with respect to the second region (14).

[0104] FIG. 11 is an enlarged plan view of the sealing portion of a pouch formed by a sealing device according to Example 1 of the present invention around a lead film, and FIG. 12 is a cross-sectional view taken along line III-III' of FIG. 11.

[0105] Referring to FIGS. 9, 11, and 12, a sealing protrusion (230) may be provided on the side sealing surface (212). A pair of sealing protrusions (230) may be provided to have a predetermined interval from each other in the width direction of the side sealing surface (212). The first sealing protrusion (231) may be formed on the inner edge of the side sealing surface (212), and the second sealing protrusion (232) may be formed on the outer edge of the side sealing surface (212).

[0106] When the sealing block (200) pressurizes the pouch (10), a greater pressure may be applied to the lead film (30) at a position corresponding to the sealing protrusion (230) than to a portion where the sealing protrusion (230) is not formed.

[0107] In other words, pressure is applied to the portion of the lead film (30) corresponding to the widthwise edges of the side sealing surface (212) due to the sealing protrusion (230), and as a result, the phenomenon of the molten lead film (30) being separated in the widthwise direction of the side sealing surface (212) (parallel to the y-axis), i.e., in the inner-outer direction of the pouch (10), can be prevented.

[0108] In this case, the lead film (30) pressed by the side sealing surface (212) can move in a direction that fills the gap (S) generated between the pouch (10) and the lead film (30), instead of being separated in the inside-outside direction of the pouch (10). That is, the flow of the lead film (30) in the width direction (parallel to the y-axis) of the side sealing surface (212) is restricted due to the sealing protrusion (230), and can flow in the length direction (parallel to the x-axis) of the side sealing surface (212) to fill the gap (S) (see FIG. 10).

[0109] By the sealing protrusion (230) of the sealing device, a pressed portion (15) may be formed in the sealing portion (12) of the pouch (10). The pressed portion (15) may be a portion formed by being pressed by the sealing protrusion (230). The pressed portion (15) may be formed in the side region (13B) and may extend in the longitudinal direction (parallel to the x-axis) of the side region (13B). The pressed portion (15) may be formed on both edges in the width direction (parallel to the y-axis) of the side region (13B) of the sealing portion (12).

[0110] A pair of pressing portions (15) may be provided at a predetermined interval in the width direction (parallel to the y-axis) of the side region (13B). More specifically, the pressing portion (15) may include a first pressing portion (15A) formed along the inner edge of the side region (13B) and a second pressing portion (15B) formed along the outer edge of the side region (13B).

[0111] The length of the pressing portion (15) may correspond to the length of the side region (13B). That is, the length of the pressing portion (15) may be the same as or similar to the length of the side region (13B).

[0112] Meanwhile, since the sealing block (200) forms the sealing portion (12) by applying pressure from both sides with the pouch (10) in between, the sealing portion (12) can have a symmetrical shape on both sides. That is, the first region (13) can be located on both sides of the sealing portion (12). More specifically, the center region (13A), the side region (13B), and the pressing portion (15) can be located on both sides of the sealing portion (12). Similarly, the second region (14), the inclined region (16), and the third region (17) can also be located on both sides of the sealing portion (12).

[0113] Example 2

[0114] Fig. 13 is an enlarged plan view of the sealing portion of a pouch formed by a sealing device according to Example 2 of the present invention, around a lead film.

[0115] In Embodiment 2 of the present invention, there may be a difference from Embodiment 1 in that the sealing protrusion (230) of the sealing device extends beyond the side sealing surface (212) to the second sealing surface (220). Except for the difference, it should be noted that the contents of the secondary battery according to Embodiment 1 of the present invention described above can be commonly applied to Embodiment 2 as well, and therefore, contents common to Embodiment 1 will be omitted as much as possible, and Embodiment 2 will be described focusing on the differences from Embodiment 1.

[0116] Referring to Fig. 13, the sealing protrusion (230) may be provided to extend to the second sealing surface (220). That is, the sealing protrusion (230) may be formed across the side sealing surface (212) and the second sealing surface (220). More specifically, the sealing protrusion (230) may extend between the center sealing surface (211) and the third sealing surface (240).

[0117] In this case, the phenomenon of additional leakage (c) of the lead film (30) that may occur in the area of ​​the lead film (30) that does not overlap with the lead metal (20) can be prevented.

[0118] Additionally, in the case of a secondary battery manufactured by such a sealing device, the pressing portion (15) formed in the sealing portion (12) may extend beyond the side region (13B) to the second region (14). The pressing portion (15) may extend between the center region (13A) and the third region (17).

[0119] In the above description, although the present invention has been described by limited embodiments and drawings, the above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention.

[0120] Accordingly, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical concepts within the scope equivalent thereto should be construed as being included within the scope of the present invention.

[0121] [Explanation of symbols]

[0122] 10: Pouch 11: Storage compartment

[0123] 12: Sealing section 13: Area 1

[0124] 13A: Center area 13B: Side area

[0125] 14: Second area 15: Pressing area

[0126] 15A: First pressing part 15B: Second pressing part

[0127] 16: Slope area 17: Third area

[0128] 20: Lead metal 30: Lead film

[0129] 200; Sealing block 210: First sealing surface

[0130] 211: Center sealing surface 212: Side sealing surface

[0131] 220: Second sealing surface 230: Sealing projection

[0132] 231: First sealing projection 232: Second sealing projection

[0133] 240: Third sealing surface

Claims

1. A sealing device including a lead film wrapping a lead metal and a sealing block provided to seal a pouch surrounding the lead film, The above sealing block, Including a first sealing surface provided to seal a central portion of the lead film overlapping the lead metal; The above first sealing surface is, Center sealing surface; and Includes side sealing surfaces positioned on both sides of the center sealing surface and formed with a step from the center sealing surface, A sealing device, wherein a sealing projection is provided on the side sealing surface to protrude with a predetermined thickness in the pressing direction of the sealing block to prevent the lead film from flowing in the width direction of the sealing surface.

2. In paragraph 1, A sealing device in which the side sealing surface extends from an end of the center sealing surface and is provided with a step in the pressing direction from the center sealing surface.

3. In paragraph 1, The above sealing block, A sealing device further comprising a second sealing surface provided at a level different from the first sealing surface to seal both ends of the lead film and the pouch.

4. In paragraph 3, A sealing device in which the center sealing surface, the side sealing surface, and the second sealing surface are sequentially provided in steps in the pressing direction.

5. In paragraph 1, A sealing device in which the side sealing surface overlaps the widthwise end area of ​​the lead metal.

6. In paragraph 3, A sealing device, wherein an inclined portion is provided between the side sealing surface and the second sealing surface, and extends obliquely between one end of the side sealing surface and one end of the second sealing surface.

7. In paragraph 3, A sealing device, wherein the sealing projection has a shape extending along a length direction perpendicular to the width direction of the side sealing surface.

8. In paragraph 3, A sealing device in which the above sealing projections are provided in plurality at a predetermined interval in the width direction of the side sealing surface.

9. In paragraph 3, A sealing device in which the above sealing projection is formed on the width-wise edge of the side sealing surface.

10. In paragraph 8, The above sealing projection is, A first sealing projection formed on one edge in the width direction of the side sealing surface; and A sealing device including a second sealing projection formed on a width-wise other edge of the side sealing surface.

11. In paragraph 7, A sealing device in which the above sealing projection is provided to extend beyond the side sealing surface to the second sealing surface.

12. In paragraph 1, A sealing device in which the above sealing blocks are provided as a pair and are arranged to face each other in the pressing direction.

13. A pouch including a storage portion for accommodating an electrode assembly and a sealing portion positioned around the storage portion; A lead metal connected to the above electrode assembly and protruding outward from the sealing portion; and Includes a lead film surrounding the lead metal and sealing the sealing portion, The above sealing part, It includes a first region that is sealed with the above pouch and the above lead film and overlaps with the above lead metal, The above first area is, center area; and Includes side regions positioned on both sides of the above center region and formed with a step from the above center region, A secondary battery, wherein a pressed portion extending in the longitudinal direction of the side region is formed in the side region.

14. In paragraph 13, The above pressing part is, A secondary battery, comprising a pair of cells extending parallel to each other at a predetermined interval in the width direction of the above-mentioned side region.

15. In paragraph 13, A secondary battery, wherein the above-mentioned pressing portion is formed on both edges in the width direction of the side region.

16. In paragraph 13, The above sealing part, A secondary battery, wherein both ends of the lead film and the pouch are sealed, and further includes a second region that is stepped from the first region.

17. In paragraph 16, A secondary battery, wherein the center region, the side region, and the second region are sequentially provided in steps in the thickness direction of the sealing portion.

18. In paragraph 16, The above sealing part, A secondary battery further comprising an inclined region formed between the side region and the second region and extending obliquely between one end of the side sealing surface and one end of the second sealing surface.

19. In paragraph 16, A secondary battery, wherein the above-mentioned pressing portion extends beyond the side region to the second region.

20. In paragraph 13, A secondary battery, wherein the center region, side region and pressing portion are located on both sides of the sealing portion.

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