Secondary battery and method for manufacturing the same

Abstract

The present disclosure relates to a secondary battery and a method for manufacturing the same, and the secondary battery according to an aspect of the present disclosure includes an electrode assembly extending in a direction; a cap including a cover portion disposed at one side of the electrode assembly in a length direction; and an outer packaging film including an accommodation portion that wraps the electrode assembly in a peripheral direction and an edge portion disposed at one side of the accommodation portion in a width direction, and having one surface that contacts an outer surface of the cover portion, wherein the cap further includes a reinforcement portion disposed opposite the cover portion with the edge portion positioned therebetween; and a cap-side connection portion connecting the reinforcement portion to the cover portion.

Description

Secondary battery and manufacturing method thereof

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0111983, filed August 21, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery and a method for manufacturing the same, and more specifically, to a secondary battery capable of charging and discharging electric energy and a method for manufacturing the same.

[0005] Common types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. These batteries are used not only in small products such as digital cameras, DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also in larger products requiring high output, such as electric and hybrid vehicles, as well as in power storage devices that store surplus power or renewable energy, and as backup power storage devices.

[0006] At this time, the secondary battery includes an electrode assembly comprising a stacked positive electrode, negative electrode, and separator, a case housing the electrode assembly, and electrode leads for conducting current between the electrode assembly and the outside. These secondary batteries are sometimes referred to as cylindrical, square, or pouch-shaped, depending on the structure or shape of the case. The case requires certain functions for the operation of the secondary battery.

[0007] Recently, development has been underway for secondary battery cases, which include a pair of caps covering each side of the electrode assembly and an outer film surrounding the electrode assembly. These cases require sealing to prevent leakage of internal materials (e.g., electrolyte) and ensure safety.

[0008] The present invention has been devised to solve the above problems, and the object of the present invention is to provide a secondary battery with improved confidentiality and a method for manufacturing the same.

[0009] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0010] According to one aspect of the present invention, a secondary battery is provided, including: an electrode assembly extending in one direction; a cap including a cover portion disposed on one longitudinal side of the electrode assembly; and an outer film including a receiving portion circumferentially surrounding the electrode assembly and a border portion disposed on one widthwise side of the receiving portion and having one side in contact with an outer surface of the cover portion, wherein the cap further includes a reinforcing portion disposed on an opposite side of the cover portion with the border portion interposed therebetween; and a cap-side connecting portion connecting the reinforcing portion and the cover portion.

[0011] At this time, the reinforcing part can face the other side of the frame part.

[0012] At this time, the reinforcing part can be in contact with the other surface of the border part.

[0013] At this time, the cap may further include a plurality of protrusions protruding from the reinforcing portion toward the edge portion.

[0014] At this time, the cross-section of the protrusion may decrease as it moves away from the reinforcing portion.

[0015] At this time, the outer film may further include an additional border portion arranged to overlap the border portion between the cover portion and the reinforcement portion; and a film-side connecting portion connecting the additional border portion and the border portion.

[0016] At this time, the film side connecting portion may be positioned adjacent to the cap side connecting portion.

[0017] At this time, the cap may further include an additional reinforcing portion interposed between the frame portion and the additional frame portion; and an additional cap-side connecting portion connecting the additional reinforcing portion and the reinforcing portion.

[0018] At this time, the cap-side connecting portion and the cap-side additional connecting portion may be provided on each side of the reinforcing portion in the longitudinal direction of the electrode assembly.

[0019] At this time, the cap-side additional connection part may have a shape that is bent from the reinforcement part toward the additional reinforcement part.

[0020] At this time, the reinforcing part can be joined to the other surface of the edge part by heat or pressure.

[0021] At this time, the caps are configured as a pair, and the pair of caps can be provided on each of the longitudinal sides of the electrode assembly.

[0022] At this time, the reinforcing part may extend in the longitudinal direction of the electrode assembly, and the connecting part may be located on one side of the extension direction of the reinforcing part.

[0023] At this time, the connecting portion may have a shape that is bent from the cover portion toward the reinforcing portion.

[0024] At this time, the cover part includes a cover part having a plate shape to cover one side of the electrode assembly; and a side wall part extending from the edge of the cover part toward the electrode assembly, the edge part surrounding the outer circumference of the side wall part, and the reinforcing part may be provided in multiple pieces and arranged along the perimeter of the cover part.

[0025] At this time, the cover portion has a polygonal shape, the side wall portion is configured in a plurality of pieces and extends from each edge of the cover portion, and the plurality of reinforcing parts can be configured to correspond to each of the plurality of side wall portions.

[0026] According to another aspect of the present invention, a method for manufacturing a secondary battery is provided, comprising: arranging a cap including a cover portion on one longitudinal side of an electrode assembly extending in one direction; surrounding the electrode assembly with a receiving portion of an outer film, arranging a border portion of the outer film such that one side is in contact with an outer surface of the cover portion; and deforming a connecting portion connecting the reinforcing portion and the cover portion so that a reinforcing portion extending from the cover portion of the cap is arranged on an opposite side of the cover portion with the border portion therebetween.

[0027] At this time, in the step of deforming the connecting portion, the connecting portion can be bent from the cover portion toward the other surface of the edge portion.

[0028] At this time, a step of combining the other surface of the above-mentioned border portion and the above-mentioned reinforcement portion may be further included.

[0029] At this time, in the step of combining the frame and the reinforcement, heat or pressure may be applied to the outer surface of the reinforcement.

[0030] According to one aspect of the present invention, since the edge portion of the outer film is placed on the outer surface of the cover portion of the cap, and the reinforcing portion of the cap is arranged on the opposite side of the cover portion with the edge portion in between, the bonding area between the cap and the outer film can be increased. As a result, the airtightness of the internal space surrounded by the cap and the outer film can be improved.

[0031] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0032] FIG. 1 is a perspective view of a secondary battery according to a first embodiment of the present invention viewed from above.

[0033] Figure 2 is a cross-sectional view according to II of Figure 1.

[0034] Figure 3 is an enlarged view of part A of Figure 2.

[0035] FIG. 4 is an enlarged view of a section corresponding to section A of FIG. 2 in a cross-sectional view of a secondary battery according to a second embodiment of the present invention.

[0036] FIG. 5 is an enlarged view of a section corresponding to section A of FIG. 2 in a cross-sectional view of a secondary battery according to a third embodiment of the present invention.

[0037] FIG. 6 is an enlarged view of a section corresponding to section A of FIG. 2 in a cross-sectional view of a secondary battery according to the fourth embodiment of the present invention.

[0038] FIG. 7 is an enlarged view of a section corresponding to section A of FIG. 2 in a cross-sectional view of a secondary battery according to the fifth embodiment of the present invention.

[0039] Figure 8 is a flowchart of a secondary battery manufacturing method according to one embodiment of the present invention.

[0040] FIG. 9 is a drawing for explaining step S40 of a secondary battery manufacturing method according to one embodiment of the present invention.

[0041] Figure 10 is a drawing for explaining step S40 according to a modified example of a manufacturing method according to one embodiment of the present invention. In this case, the area corresponding to the film-side connecting portion of the outer film is indicated by hatching.

[0042] FIG. 11 is a drawing specifically explaining step S40 of a manufacturing method according to one embodiment of the present invention.

[0043] FIG. 12 is a drawing specifically explaining step S40 according to a modified example of a manufacturing method according to one embodiment of the present invention.

[0044] Preferred embodiments of the present invention are described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0045] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0046] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0047] Fig. 1 is a perspective view of a secondary battery according to a first embodiment of the present invention, viewed from above. Fig. 2 is a cross-sectional view taken along line II of Fig. 1. Fig. 3 is an enlarged view of part A of Fig. 2.

[0048] FIGS. 1 to 3 disclose a secondary battery according to a first embodiment of the present invention. Referring to FIGS. 1 to 3, a secondary battery (1) according to the first embodiment of the present invention may be a secondary battery for charging and discharging electric energy.

[0049] The secondary battery (1) according to the present embodiment may have a form in which an electrode assembly (10) capable of charging and discharging electric energy is sealed together with an electrolyte by a cap (20) and an outer film (40). At this time, the secondary battery (1) according to the present embodiment may be configured such that the reinforcing portion (26) of the cap (20) covers the widthwise (X-axis direction) edge portion of the outer film (40).

[0050] Accordingly, the secondary battery (1) according to the first embodiment of the present invention can have a wider bonding area between the cap (20) and the outer film (40), so that the airtightness (or sealing) of the electrode assembly (10) accommodated therein can be improved. Here, the bonding area of ​​the two components can mean the area where the two components are directly or indirectly bonded to each other.

[0051] Hereinafter, each component of the secondary battery according to the first embodiment of the present invention will be described in detail.

[0052] Referring to FIG. 2, a secondary battery (1) according to the first embodiment of the present invention may include an electrode assembly (10). The electrode assembly (10) may be a component responsible for a charge / discharge function.

[0053] To this end, the electrode assembly (10) may be formed by sequentially stacking a plurality of positive electrodes, separators, and negative electrodes. The electrode assembly (10) may be classified into a cylindrical shape, a stacked shape, or a stack & folding shape depending on its shape or structure. In the present embodiment, the type or shape of the electrode assembly (10) is not particularly limited.

[0054] At this time, the electrode assembly (10) may be equipped with an electrode tab (11). The electrode tab (11) may extend from each of a plurality of electrodes (positive or negative electrodes). The electrode tab (11) may be configured to conduct current through the electrode to the outside. For this purpose, the electrode tab (11) may be coupled to a terminal (30) described below.

[0055] Meanwhile, in the present embodiment, the electrode assembly (10) may extend in one direction. As illustrated, the electrode assembly (10) may extend in the left-right direction (X-axis direction) with reference to FIG. 2. Hereinafter, the one direction is referred to as the longitudinal direction (X-axis direction) of the electrode assembly (10).

[0056] Referring to FIGS. 1 to 3, a secondary battery (1) according to a first embodiment of the present invention may include a cap (20). The cap (20) may be configured to cover one side of the electrode assembly (10) in the longitudinal direction (X-axis direction). The cap (20) may be made of a material having a predetermined rigidity.

[0057] At this time, as illustrated, the caps (20) may be configured as a pair. And, a pair of caps (20) may cover each of the longitudinal (X-axis direction) sides of the electrode assembly (10). However, if necessary, only one cap (20) may be configured.

[0058] Hereinafter, the cap (20) located on the left side (positive direction of the X-axis) based on Fig. 2 will be described. Referring to Figs. 1 to 3, the cap (20) of the secondary battery (1) according to the first embodiment of the present invention may include a cover portion (22). The cover portion (22) may be arranged on one side of the electrode assembly (10) in the longitudinal direction (X-axis direction) to cover it.

[0059] In this embodiment, the cover portion (22) may include a plate-shaped cover portion (23) that partially covers the electrode assembly (10). As illustrated, in this embodiment, the cover portion (23) may be a square plate.

[0060] The shape of the cover portion (23) can be appropriately modified as needed. For example, the cover portion (23) may be a triangular plate or a polygonal plate having a pentagon or more angles, a circular or oval plate, or a plate having both a curved edge and a straight edge.

[0061] In this embodiment, the cover portion (22) may include a side wall portion (24) extending from the edge of the cover portion (23). The side wall portion (24) may extend from the cover portion (23) toward the electrode assembly (10). The side wall portion (24) may extend parallel to the longitudinal direction (X-axis direction) of the electrode assembly (10).

[0062] In the present embodiment, since the cover portion (23) is provided as a square plate, the side wall portion (24) may be configured with side walls extending from each of the four sides forming the frame of the square. In other words, the side wall portion (24) may have a square ring shape extending in the longitudinal direction (X-axis direction) of the electrode assembly (10). The shape of the side wall portion (24) may be appropriately modified to fit the cover portion (23).

[0063] At this time, an outer surface (24a) may be provided on the outer side of the side wall portion (24). The outer surface (24a) may be an outer peripheral surface facing a direction (Y-axis and Z-axis directions) perpendicular to the longitudinal direction (X-axis direction) of the electrode assembly (10). In the present embodiment, the outer peripheral surface of the side wall portion (24) may be collectively referred to as the outer surface (24a) of the cover portion (22).

[0064] As will be described in detail later, the outer surface (24a) of the cover portion (22) may be surrounded by a border portion (44) of an outer film (40) to be described later. The border portion (44) and the outer surface (24a) of the cover portion (22) may be joined to each other. For this purpose, a predetermined bonding layer (L) may be provided between the outer surface (24a) of the cover portion (22) and the border portion (44) of the outer film (40).

[0065] At this time, the bonding layer (L) may be formed by melting a resin layer provided on at least one of the outer surface (24a) of the cover portion (22) and the edge portion (44) of the outer film (40) by heat or pressure. Alternatively, the bonding layer (L) may be formed by applying a separate adhesive to at least one of the outer surface (24a) of the cover portion (22) and the edge portion (44) of the outer film (40). The type or material of the bonding layer (L) is not particularly limited.

[0066] Meanwhile, in the present embodiment, the cover portion (22) has been described as being formed of a plate and a side wall extending from the edge of the plate. However, the structure or shape of the cover portion (22) is not particularly limited as long as it can cover one side of the electrode assembly (10) and provide an outer surface to which an outer film (40) can be bonded.

[0067] Referring again to FIGS. 1 to 3, the cap (20) according to one embodiment of the present invention may include a reinforcing member (26). The reinforcing member (26) may be configured to improve the airtightness of the secondary battery (1) by increasing the bonding force between the cap (20) and the outer film (40).

[0068] In this embodiment, the reinforcing portion (26) may be positioned on the opposite side of the side wall portion (24) of the cover portion (22) with the edge portion (44) of the outer film (40) interposed therebetween. In other words, the edge portion (44) may be interposed between the reinforcing portion (26) and the side wall portion (24). Accordingly, one side (44a) of the edge portion (44) may face the outer surface (24a) of the cover portion (22), and the other side (44b) may face the reinforcing portion (26).

[0069] In this embodiment, the reinforcing portion (26) can be interviewed with the other surface (44b) of the edge portion (44). In this case, the interviewing of the two components can be understood to include not only direct interviewing, but also indirect interviewing via a component interposed therebetween.

[0070] Such a reinforcing member (26) may have a plate shape that covers the other side (44b) of the edge member (44). Alternatively, the reinforcing member (26) may be provided in the form of a film or sheet having a predetermined thickness.

[0071] At this time, the reinforcing portion (26) may extend in the longitudinal direction (X-axis direction) of the electrode assembly (10). In other words, the reinforcing portion (26) may extend parallel to the side wall portion (24). Through this, the bonding area between the reinforcing portion (26) and the edge portion (44) may be expanded, thereby improving the airtightness of the secondary battery (1).

[0072] Meanwhile, in the present embodiment, a bonding layer (L) may also be provided between the reinforcing portion (26) and the other surface (44b) of the edge portion (44). At this time, the bonding layer (L) may be configured in the same manner as the bonding layer (L) between the outer surface (24a) of the cover portion (22) and the edge portion (44) described above.

[0073] At this time, if the physical bonding force between the reinforcing portion (26) and the other surface (44b) of the edge portion (44) can be provided sufficiently strong, a separate bonding layer (L) may not be provided between them.

[0074] For example, if the reinforcing portion (26) is press-molded toward the other surface (44b) of the edge portion (44) so ​​that sufficient bonding force can be secured between them, the bonding layer (L) may not be provided separately. This point can also be applied to the bonding layer (L) between the outer surface (24a) of the cover portion (22) and the edge portion (44).

[0075] The cap (20) of the secondary battery (1) according to the first embodiment of the present invention may include a cap-side connecting portion (27). The cap-side connecting portion (27) may be configured to connect the reinforcing portion (26) and the cover portion (22).

[0076] In this embodiment, the cap-side connecting portion (27) may be provided on the outside of the cover portion (22) in the longitudinal direction (X-axis direction) of the electrode assembly (10). The cap-side connecting portion (27) may be located at one end of the extension direction (X-axis direction) of the reinforcing portion (26). At this time, the one end may be an end facing the outside of the electrode assembly (10).

[0077] At this time, the cap-side connecting portion (27) may be provided on the edge side of the cover portion (23) of the cover portion (22). The cap-side connecting portion (27) may extend along the edge of the cover portion (23). Through this, the reinforcing portion (26) and the cover portion (22) may be strongly connected.

[0078] In this embodiment, the cap-side connecting portion (27) may have a shape that is bent from the cover portion (23) of the cover portion (22) toward the reinforcing portion (26). However, the shape or position of the cap-side connecting portion (27) is not particularly limited as long as it can connect the reinforcing portion (26) and the cover portion (22).

[0079] Meanwhile, referring to FIG. 1, the reinforcing portion (26) and the cap-side connecting portion (27) of the cap (20) according to the first embodiment of the present invention may be configured in multiple numbers and arranged along the perimeter of the cover portion (23). As illustrated, the reinforcing portions (26) and the cap-side connecting portions (27) may be configured in four pairs and may be provided on each edge of the cover portion (23) having a square shape.

[0080] Through this, the bonding area of ​​the outer film (40) and the cap (20) can be increased in the circumferential direction of the electrode assembly (10), so that the airtightness of the secondary battery (1) can be further improved. The number of reinforcing parts (26) and cap-side connecting parts (27) can be appropriately changed depending on the shape of the cover part (22).

[0081] Referring to FIGS. 1 and 2, a secondary battery (1) according to the first embodiment of the present invention may include a terminal (30). The terminal (30) may be configured to conduct current through the electrode assembly (10) to the outside. For this purpose, the terminal (30) may be made of a conductive material.

[0082] In this embodiment, the terminal (30) may include a body portion (32). The body portion (32) may penetrate the cover portion (23) of the cap (20). The body portion (32) may have a cylindrical shape, but is not limited thereto.

[0083] In this embodiment, the terminal (30) may include an outer catch (34). The outer catch (34) may be provided on one side of the body (32). The one side may be a portion facing the outside of the electrode assembly (10).

[0084] At this time, the outer catch portion (34) may have a larger cross-sectional area than the body portion (32). As a result, the outer catch portion (34) may be caught on the cover portion (23). Accordingly, the terminal (30) may be restricted from moving beyond a certain distance toward the electrode assembly (10).

[0085] In the present embodiment, the terminal (30) may include an inner hook portion (36). The inner hook portion (36) may be provided on the other side of the body portion (32). The other side may be a portion facing the electrode assembly (10). An electrode tab (11) may be coupled to the inner hook portion (36). For example, the electrode tab (11) may be welded to the outer surface of the inner hook portion (36), but is not limited thereto.

[0086] At this time, the inner catch portion (36) may have a larger cross-sectional area than the body portion (32). As a result, the inner catch portion (36) may be caught on the cover portion (23). Accordingly, the terminal (30) may be restricted from moving outward from the electrode assembly (10) beyond a certain distance.

[0087] Meanwhile, although not specifically shown, the terminals (30) may be configured as a pair. One of the pair of terminals (30) may be electrically connected to the positive electrode of the electrode assembly (10), and the other may be electrically connected to the negative electrode.

[0088] A pair of terminals (30) may be provided on each of the longitudinal (X-axis) sides of the electrode assembly (10). Alternatively, a pair of terminals (30) may be arranged together on one longitudinal (X-axis) side of the electrode assembly (10). The position of the terminals (30) is not particularly limited.

[0089] In this embodiment, the terminal (30) has been described as having a concave, round shape (or dumbbell shape) in the center so that it can be hung on the cover portion (23). However, the structure or shape of the terminal (30) is not particularly limited as long as it can conduct current to the electrode assembly (10) from the outside.

[0090] Referring again to FIGS. 1 to 3, the secondary battery (1) according to the first embodiment of the present invention may include an outer film (40). The outer film (40) may be configured to surround the remaining portion of the outer surface of the electrode assembly (10) that is not covered by the cap (20).

[0091] In this embodiment, the outer film (40) may have a certain degree of flexibility. In this way, since in this embodiment the electrode assembly (10) is partially covered by the outer film (40) that can be stretched or bent, damage to the electrode assembly (10) can be minimized.

[0092] To be more specific, the electrode assembly (10) may expand or contract during the charging and discharging process of the secondary battery (1). At this time, the outer film (40) may be deformed in response to such deformation of the electrode assembly (10), thereby preventing damage to the electrode assembly (10).

[0093] This characteristic of the secondary battery (1) can prevent damage to the electrode assembly (10) better than a square case. This is because the square case hardly experiences any shape change, and thus the case and the expanding electrode assembly (10) may interfere excessively with each other.

[0094] Meanwhile, the outer film (40) of the secondary battery (1) according to the first embodiment of the present invention may include a receiving portion (42). The receiving portion (42) may surround the electrode assembly (10) in the circumferential direction between a pair of caps (20).

[0095] Here, the circumferential direction may be a direction that wraps around the longitudinal direction (X-axis direction) of the electrode assembly (10). Through this, the electrode assembly (10) can be isolated and sealed from the outside by the cap (20) and the outer film (40).

[0096] In this way, in this embodiment, unlike conventional pouch-type cases, the electrode assembly (10) can be sealed without having to form a separate cup portion on the outer film (40). Here, the cup portion may refer to a portion that is concavely sunken in a cup shape so that the electrode assembly (10) can be inserted. Therefore, in the secondary battery (1), problems such as cracks that may occur during the molding process of the cup portion may not occur.

[0097] Meanwhile, the outer film (40) of the secondary battery (1) according to the first embodiment of the present invention may include a border portion (44). The border portion (44) may be provided on one side of the width direction (X-axis direction) of the receiving portion (42). Here, the width direction of the receiving portion (42) may be parallel to the length direction of the electrode assembly (10).

[0098] At this time, the edge portions (44) may be provided in pairs, and may be provided on both sides of the width direction of the receiving portion (42). The edge portions (44) may be provided along the width direction (X-axis direction) edge of the receiving portion (42). In other words, the edge portions (44) may extend in the circumferential direction of the electrode assembly (10).

[0099] Referring to FIGS. 2 and 3, as described above, the frame portion (44) can surround the outer surface (24a) of the cover portion (22). The frame portion (44) can surround the outer surface (24a) of the cover portion (22) in the circumferential direction of the electrode assembly (10).

[0100] In this embodiment, one side (44a) of the frame portion (44) can be bonded to the outer surface (24a) of the cover portion (22) via a bonding layer (L). Of course, one side (44a) of the frame portion (44) can also be bonded by directly contacting the outer surface (24a) of the cover portion (22).

[0101] At this time, as described above, the rim portion (44) may be interposed between the outer surface (24a) of the cover portion (22) and the reinforcing portion (26). Alternatively, the rim portion (44) may be sandwiched between the outer surface (24a) of the cover portion (22) and the reinforcing portion (26). The other surface (44b) of the rim portion (44) may be bonded to the reinforcing portion (26) via a bonding layer (L). Of course, the other surface (44b) of the rim portion (44) may also be bonded to the reinforcing portion (26) by directly contacting it.

[0102] As described above, in the secondary battery (1) according to the first embodiment of the present invention, both sides (44a, 44b) of the edge portion (44) of the outer film (40) can be bonded to the outer surface (24a) and the reinforcing portion (26) of the cover portion (22), respectively. Accordingly, the bonding area between the cap (20) and the outer film (40) can be increased, so that the airtightness of the secondary battery (1) can be improved.

[0103] Hereinafter, a secondary battery according to another embodiment of the present invention will be described. When describing a secondary battery according to another embodiment of the present invention, the differences between the secondary battery according to the first embodiment of the present invention described above and the secondary battery according to another embodiment will be explained.

[0104] FIG. 4 is an enlarged view of a portion corresponding to portion A of FIG. 2 in a cross-sectional view of a secondary battery according to a second embodiment of the present invention. FIG. 5 is an enlarged view of a portion corresponding to portion A of FIG. 2 in a cross-sectional view of a secondary battery according to a third embodiment of the present invention. FIG. 6 is an enlarged view of a portion corresponding to portion A of FIG. 2 in a cross-sectional view of a secondary battery according to a fourth embodiment of the present invention. FIG. 7 is an enlarged view of a portion corresponding to portion A of FIG. 2 in a cross-sectional view of a secondary battery according to a fifth embodiment of the present invention. At this time, components indicated by the same drawing reference numerals as those described above can be understood as the same components performing the same function.

[0105] FIG. 4 discloses a secondary battery according to a second embodiment of the present invention. Referring to FIG. 4, the cap (120) of the secondary battery (101) according to the second embodiment of the present invention may further include a plurality of protrusions (127). The protrusions (127) may be configured to further enhance the bonding strength between the cap (120) and the outer film (40).

[0106] In this embodiment, the protrusion (127) may protrude from the reinforcing portion (26) toward the outer film (40). At this time, the cross-section of the protrusion (127) may decrease as it moves away from the reinforcing portion (26). In other words, the protrusion (127) may have a pointed shape.

[0107] This protrusion (127) can be pressed into the other surface (44b) of the rim (44). The protrusion (127) can be physically or structurally connected to the rim (44). Accordingly, the bonding force between the reinforcing portion (26) and the rim (44) can be increased. This can improve the airtightness of the secondary battery (101).

[0108] FIG. 5 discloses a secondary battery according to a third embodiment of the present invention. Referring to FIG. 5, the outer film (240) of the secondary battery (201) according to the third embodiment of the present invention may include an additional border portion (246). The additional border portion (246) may be configured to increase the bonding area between the outer film (240) and the cap (220).

[0109] In this embodiment, the additional border portion (246) may be positioned to overlap the border portion (44) between the reinforcement portion (26) and the outer surface (24a) of the cover portion (22). The additional border portion (246) may extend in the longitudinal direction (X-axis direction) of the electrode assembly (10) parallel to the border portion (44).

[0110] At this time, one side of the additional border portion (246) can be combined with the reinforcing portion (26) via the bonding layer (L). Here, one side can be a side facing the outside of the cover portion (22). Meanwhile, the other side of the additional border portion (246) can be combined with the additional reinforcing portion (228) described later via the bonding layer (L). Here, the other side can be a side facing the cover portion (22). Therefore, the bonding area of ​​the cap (220) and the outer film (240) can be improved.

[0111] Referring again to FIG. 5, in this embodiment, the outer film (240) may include a film-side connecting portion (247). The film-side connecting portion (248) may be configured to connect the edge portion (44) and the additional edge portion (246).

[0112] At this time, the film-side connecting portion (248) may be located at one end of the extension direction (X-axis direction) of the additional border portion (246). The one end of the additional border portion (246) may be an end facing the outside of the electrode assembly (10).

[0113] In this embodiment, the film-side connecting portion (248) may have a shape that is bent from the edge portion (44) toward the additional edge portion (246). The film-side connecting portion (248) may be positioned adjacent to the cap-side connecting portion (27) of the cap (220). In other words, the film-side connecting portion (248) and the cap-side connecting portion (27) may be in close contact with each other.

[0114] The cap (220) of the secondary battery (201) according to the third embodiment of the present invention may further include an additional reinforcing member (228). The additional reinforcing member (228) may be configured to increase the bonding area between the outer film (240) and the cap (220).

[0115] In this embodiment, an additional reinforcing member (228) may be interposed between the additional rim member (226) and the rim member (44). The additional reinforcing member (228) may extend in the longitudinal direction (X-axis direction) of the electrode assembly (10). The additional reinforcing member (228) may extend parallel to the outer surface (24a) of the cover member (22) or the reinforcing member (26).

[0116] In this embodiment, the additional reinforcing member (228) can be respectively bonded to the frame member (44) and the additional frame member (226) via the bonding layer (L). Through this, the bonding area between the cap (220) and the outer film (240) can be further increased, thereby improving the airtightness of the secondary battery (201).

[0117] Meanwhile, in the present embodiment, the cap (220) may further include an additional cap-side connecting portion (229). The additional cap-side connecting portion (229) may be configured to connect the reinforcing portion (26) and the additional reinforcing portion (228).

[0118] In this embodiment, the cap-side additional connection portion (229) may be located at one end of the extension direction (X-axis direction) of the reinforcement portion (26). At this time, the one end may be an end facing the electrode assembly (10). The cap-side additional connection portion (229) and the cap-side connection portion (27) may be provided on each of the two sides of the extension direction (X-axis direction) of the reinforcement portion (26).

[0119] At this time, in the present embodiment, the cap-side additional connection portion (229) may have a shape that is bent from the reinforcement portion (26) toward the additional reinforcement portion (228). Accordingly, the additional reinforcement portion (228) and the cap-side additional connection portion (229) of the cap (220) and the additional edge portion (246) and the film-side connection portion (248) of the outer film (240) may have a shape that is interlocked and hooked to each other. Accordingly, the bonding strength between the cap (220) and the outer film (240) may be improved.

[0120] Meanwhile, in the present embodiment, the cover portion (22), the reinforcing portion (26), and the additional reinforcing portion (228) of the cap (220) and the edge portion (44) and the additional edge portion (246) of the outer film (240) are described as being joined via the bonding layer (L). However, if the cap (220) and the outer film (240) can be joined by being press-molded with sufficient strength, part or all of the bonding layer (L) may not be provided.

[0121] FIG. 6 discloses a secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 6, among the configurations of the secondary battery (301) according to the fourth embodiment of the present invention, other configurations, excluding the configuration related to the bonding layer, may be configured in the same manner as the secondary battery according to the first embodiment described above.

[0122] In this embodiment, a first bonding layer (L1) may be provided between the outer surface (24a) of the cover portion (22) and the inner surface (44a) of the frame portion (44). At this time, the inner surface (44a) of the frame portion (44) may be a surface facing the outer surface (24a) of the cover portion (22). The first bonding layer (L1) may be formed by melting a resin layer provided on at least one of the outer surface (24a) of the cover portion (22) and the inner surface (44a) of the frame portion (44).

[0123] Meanwhile, in the present embodiment, a second bonding layer (L2) made of a different material from the first bonding layer (L1) may be provided between the reinforcing portion (26) and the outer surface (44b) of the rim portion (44). Here, the outer surface (44b) of the rim portion (44) may be a surface facing the outer side of the cover portion (22). The outer surface (44b) may face the inner surface (44a).

[0124] At this time, in the present embodiment, the second bonding layer (L2) may be formed by applying an additional material. For example, the second bonding layer (L2) may be formed by an adhesive applied to at least one of the outer surface (44b) of the rim portion (44) and the outer surface (26a) of the reinforcing portion (26), but is not limited thereto. At this time, the outer surface (26a) of the reinforcing portion (26) may be a surface facing the outer surface (44a) of the rim portion (44).

[0125] Meanwhile, in the present embodiment, it has been described that the first and second bonding layers (L1, L2) are provided between the frame portion (44), the cover portion (22), and the reinforcing portion (26). However, if necessary, at least one of the first and second bonding layers (L1, L2) may not be provided separately. For example, the second bonding layer (L2) may not be provided, and the outer surface (44a) of the reinforcing portion (26) and the frame portion (44) may be configured to be in contact with each other.

[0126] FIG. 7 discloses a secondary battery according to a fifth embodiment of the present invention. Referring to FIG. 7, among the configurations of the secondary battery (401) according to the fifth embodiment of the present invention, other configurations besides the bonding layer may be configured in the same manner as the secondary battery according to the third embodiment described above.

[0127] In this embodiment, a first bonding layer (L1) may be provided between the outer surface (24a) of the cover portion (22) and the first surface (44a) of the rim portion (44), between the cap-side connecting portion (27) and the second surface (44b) of the rim portion (44), and between the reinforcing portion (26) and the third surface (44c) of the rim portion (44). At this time, the first bonding layer (L1) may be configured in the same manner as the first bonding layer of the secondary battery according to the fourth embodiment described above.

[0128] Here, the first surface (44a) of the frame portion (44) may be a surface facing the outer surface (24a) of the cover portion (22), the second surface (44b) may be a surface facing the cap-side connecting portion (27), and the third surface (44c) may be a surface facing the outer side of the cover portion (22) and facing the reinforcing portion (26).

[0129] Meanwhile, in the present embodiment, a second bonding layer (L2) may be provided between the fourth side (44d) of the frame portion (44) and the additional reinforcement portion (228) and between the fifth side (44e) of the frame portion (44) and the additional reinforcement portion (228). At this time, the second bonding layer (L2) may be configured in the same manner as the second bonding layer of the secondary battery according to the fourth embodiment described above.

[0130] Here, the fourth side (44d) of the border portion (44) may be a side facing the third side (44c) and facing the additional reinforcement portion (228), and the fifth side (44e) may be a side facing the first side (44a) and facing the additional reinforcement portion (228).

[0131] Meanwhile, in the present embodiment, it has been described that the first and second bonding layers (L1, L2) are provided between the frame portion (44), the cover portion (22), the cap-side connecting portion (27), the reinforcing portion (26), and the additional reinforcing portion (228), but at least one of the first and second bonding layers (L1, L2) may not be provided separately.

[0132] Meanwhile, in the present embodiment, the length (hereinafter referred to as the first length) when the frame portion (44), the film-side connecting portion (248), and the additional frame portion (229) are spread left and right (in the X-axis direction) is formed to be shorter than the length (hereinafter referred to as the second length) when the cap-side connecting portion (27), the reinforcing portion (26), the cap-side additional connecting portion (229), and the additional reinforcing portion (228) are spread left and right, so that the additional frame portion (229) is interposed between the reinforcing portion (26) and the additional reinforcing portion (228).

[0133] However, the first length and the second length may be appropriately changed as needed. For example, the first length may be provided to be longer than or equal to the second length, so that the additional border portion (229) may have a shape that is rolled or folded between the reinforcing portion (26) and the additional reinforcing portion (228).

[0134] Hereinafter, a method for manufacturing a secondary battery according to one embodiment of the present invention (hereinafter referred to as a "manufacturing method") will be described. The manufacturing method according to one embodiment of the present invention may be a method for manufacturing a secondary battery according to the previously described embodiment of the present invention.

[0135] FIG. 8 is a flowchart of a secondary battery manufacturing method according to an embodiment of the present invention. FIG. 9 is a diagram for explaining step S40 of a secondary battery manufacturing method according to an embodiment of the present invention. FIG. 10 is a diagram for explaining step S40 according to a modified example of a manufacturing method according to an embodiment of the present invention. In this case, an area corresponding to a film-side connecting portion of the outer film is indicated by hatching. FIG. 11 is a diagram for specifically explaining step S40 of a manufacturing method according to an embodiment of the present invention. FIG. 12 is a diagram for specifically explaining step S40 according to a modified example of a manufacturing method according to an embodiment of the present invention.

[0136] Referring to FIGS. 1 to 3, 8 and 9, in a manufacturing method according to one embodiment of the present invention, a cap (20) is placed on one side of the electrode assembly (10) in the longitudinal direction (X-axis direction) (S10).

[0137] At this time, in the present embodiment, the caps (20) may be configured as a pair and may be placed on each side of the electrode assembly (10). Here, the cap (20) may be any one of the caps of the secondary battery according to the first embodiment of the present invention.

[0138] At this time, in the present embodiment, the reinforcing portion (26') of the cap (20) may have a shape that extends outward from the cover portion (22). The direction in which the reinforcing portion (26') extends is not particularly limited as long as it can provide a space in which the outer film (40) can surround the outer surface of the cover portion (22) in step S20 described later.

[0139] Next, in a manufacturing method according to one embodiment of the present invention, a cap (20) is placed (S10), and the cap (20) and the electrode assembly (10) are surrounded by an outer film (40) (S20). Accordingly, the electrode assembly (10) can be sealed by the cap (20) and the outer film (40).

[0140] More specifically, in step S20, the electrode assembly (10) can be surrounded in the circumferential direction by the receiving portion (42) of the outer film (40), and the outer surface (24a) of the cover portion (22) can be surrounded in the circumferential direction by the edge portion (44).

[0141] Next, in a manufacturing method according to one embodiment of the present invention, a cap (20) and an electrode assembly (10) are surrounded by an outer film (40), and a cover portion (22) of the cap (20) and a border portion (44) of the outer film (40) are combined (S30).

[0142] To this end, heat or pressure may be applied to at least one of the cover portion (22) and the frame portion (44) in step S30. The heat or pressure may melt the resin layer provided in at least one of the cover portion (22) and the frame portion (44). Accordingly, a bonding layer (L) may be formed.

[0143] Of course, the bonding layer (L) formed in step S30, if necessary, may be formed of an adhesive applied to at least one of the cover portion (22) and the frame portion (44). Alternatively, in step S30, the frame portion (44) may be bonded by being pressed against the outer surface (24a) of the cover portion (22). In this modified example, the bonding layer (L) may not be provided separately.

[0144] Meanwhile, referring to FIGS. 2, 8 and 9, in a manufacturing method according to one embodiment of the present invention, a cover part (22) and a frame part (44) are combined (S30), and a cap-side connecting part (27') of a cap (20) is deformed so that a reinforcing part (26) is placed on the opposite side of the cover part (22) with the frame part (44) in between (S40).

[0145] To this end, in step S40, the cap-side connecting portion (27') can be bent from the cover portion (22) toward the other side (44b) of the frame portion (44). Here, the other side (44b) may be a side of the outer surface of the frame portion (44) that faces the outer side of the cover portion (22).

[0146] Meanwhile, in step S40 according to the present embodiment, the reinforcing part (26) can be pressed toward the edge part (44). As a result, the reinforcing part (26) and the edge part (44) can be brought into close contact and interviewed.

[0147] Referring again to FIGS. 2 and 8, in a manufacturing method according to one embodiment of the present invention, the cap-side connecting portion (27') can be deformed (S40), and the reinforcing portion (26) of the cap (20) and the edge portion (44) of the outer film (40) can be combined (S50).

[0148] To this end, heat or pressure may be applied to at least one of the reinforcing portion (26) and the edge portion (44) at step S50. The heat or pressure may melt the resin layer provided in at least one of the reinforcing portion (26) and the edge portion (44). Accordingly, a bonding layer (L) may be formed.

[0149] Of course, the bonding layer (L) formed in step S50, if necessary, may be formed of an adhesive applied to at least one of the reinforcing portion (26) and the edge portion (44). Alternatively, in step S50, the reinforcing portion (26) may be pressed toward the edge portion (44) to bond. In this modified example, the bonding layer (L) may not be provided separately.

[0150] Hereinafter, with further reference to FIGS. 10 to 12, a variation of a manufacturing method according to one embodiment of the present invention will be described. Here, the differences between the manufacturing method according to one embodiment and the manufacturing method according to the variation will be primarily described.

[0151] Referring to FIGS. 5, 8, 10 and 11, the manufacturing method according to the present modified example may be a method for manufacturing a secondary battery (201) (illustrated in FIG. 5) according to the third embodiment of the present invention described above.

[0152] In the manufacturing method according to the present modified example, the cap-side additional connection part (229) connecting the additional reinforcement part (228') and the reinforcement part (26) can be modified so that the additional reinforcement part (228') of the cap (220) comes into contact with the additional edge part (246') of the outer film (240) before step S40.

[0153] To this end, in the above step, as illustrated in FIG. 9, the cap-side additional connecting portion (229) can be bent from the reinforcing portion (26) toward the outer surface of the additional rim portion (246'). At this time, the outer surface of the additional rim portion (246') may be a surface facing the outer side of the cap (220).

[0154] Next, in the manufacturing method according to the present modified example, the additional reinforcing portion (228) and the additional rim portion (246') can be joined. To this end, heat or pressure may be applied in the above step, or an external force may be applied so that the additional reinforcing portion (228) and the additional rim portion (246') are in close contact with each other.

[0155] Next, referring to FIGS. 8, 10, and 12, step S40 is performed in the manufacturing method according to the present modified example. At this time, in step S40 according to the present modified example, the film-side connecting portion (248) of the outer film (240) and the cap-side connecting portion (27) of the cap (220) can be deformed together.

[0156] More specifically, in step S40, the cap-side connecting portion (27) and the film-side connecting portion (248) can be bent so as to be bent toward the outer surface of the edge portion (44). As a result, an additional reinforcing portion (228) can be interposed between the additional edge portion (246) and the edge portion (44). In addition, the film-side connecting portion (248) and the additional edge portion (246) and the cap-side additional reinforcing portion (229) and the additional reinforcing portion (228) can have a shape in which they are interlocked and combined with each other.

[0157] As described above, the manufacturing method according to an embodiment of the present invention can significantly increase the bonding area between the cap and the outer film. Accordingly, the secondary battery manufactured using the manufacturing method can have high airtightness.

[0158] Meanwhile, the manufacturing method according to one embodiment of the present invention has been described as a method for manufacturing secondary batteries according to the previously described embodiments. However, the manufacturing method according to this embodiment is not limited to a method for manufacturing only secondary batteries according to the embodiments of the present invention.

[0159] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0160] [Explanation of symbols]

[0161] 1, 101, 201: Secondary batteries

[0162] 10: Electrode assembly

[0163] 20, 120, 220: Cap

[0164] 30: Terminal

[0165] 40, 240: Exterior film

[0166] L: bonding layer

Claims

1. Electrode assembly extending in one direction; A cap including a cover portion disposed on one longitudinal side of the electrode assembly; and It includes an outer film including a receiving portion that surrounds the electrode assembly in a circumferential direction and a border portion that is arranged on one side of the receiving portion in the width direction and has one side in contact with the outer surface of the cover portion. The above cap is, A reinforcing member arranged on the opposite side of the cover member with the frame member interposed therebetween; and A secondary battery further comprising a cap-side connecting portion connecting the reinforcing portion and the cover portion.

2. In paragraph 1, The above reinforcement part is a secondary battery that faces the other side of the above frame part.

3. In paragraph 2, The above reinforcement part is a secondary battery that is in contact with the other surface of the frame part.

4. In paragraph 1, The above cap is, A secondary battery further comprising a plurality of protrusions protruding from the reinforcing portion toward the edge portion.

5. In paragraph 4, A secondary battery, wherein the cross-section of the above-mentioned protrusion decreases as it moves away from the above-mentioned reinforcing portion.

6. In paragraph 1, The above outer film, An additional border portion arranged to overlap the border portion between the cover portion and the reinforcement portion; and A secondary battery further comprising the additional frame portion and a film-side connecting portion connecting the frame portion.

7. In paragraph 6, A secondary battery, wherein the film-side connecting portion is positioned adjacent to the cap-side connecting portion.

8. In paragraph 6, The above cap is, An additional reinforcing member interposed between the above-mentioned frame portion and the above-mentioned additional frame portion; and A secondary battery further comprising an additional connecting portion on the cap side connecting the additional reinforcing portion to the reinforcing portion.

9. In paragraph 8, A secondary battery, wherein the cap-side connecting portion and the cap-side additional connecting portion are respectively provided on both sides of the reinforcing portion in the longitudinal direction of the electrode assembly.

10. In paragraph 8, A secondary battery, wherein the cap-side additional connecting portion has a shape that is bent from the reinforcing portion toward the additional reinforcing portion.

11. In paragraph 1, The above reinforcing part is a secondary battery that is joined to the other surface of the edge part by heat or pressure.

12. In paragraph 1, The above caps are composed of a pair, A secondary battery, wherein the above pair of caps are provided on each of the longitudinal sides of the electrode assembly.

13. In paragraph 1, The above reinforcement part extends in the longitudinal direction of the electrode assembly, The secondary battery, wherein the above connecting portion is located on one side of the extension direction of the above reinforcing portion.

14. In paragraph 1, A secondary battery, wherein the above connecting portion has a shape that is bent from the cover portion toward the reinforcing portion.

15. In paragraph 1, The above cover part, A cover portion having a plate shape to cover one side of the electrode assembly; and Including a side wall portion extending from the edge of the cover portion toward the electrode assembly, The above-mentioned border portion surrounds the outer circumference of the side wall portion, A secondary battery, wherein the above reinforcing member is provided in multiple pieces and arranged along the perimeter of the cover portion.

16. In paragraph 15, The above cover portion has a polygonal shape, The above side wall portion is composed of a plurality of pieces and extends from each edge of the cover portion, A secondary battery, wherein the plurality of reinforcing parts are configured to correspond to each of the plurality of side wall parts.

17. A step of placing a cap including a cover part on one longitudinal side of an electrode assembly extending in one direction; A step of surrounding the electrode assembly with a receiving portion of an outer film and arranging the edge portion of the outer film so that one side is in contact with the outer surface of the cover portion; and A method for manufacturing a secondary battery, comprising a step of deforming a cap-side connecting portion connecting the reinforcing portion and the cover portion so that a reinforcing portion extending from the cover portion of the cap is placed on the opposite side of the cover portion with the frame portion therebetween.

18. In paragraph 17, A method for manufacturing a secondary battery, wherein, in the step of deforming the cap-side connecting portion, the cap-side connecting portion is bent from the cover portion toward the other surface of the frame portion.

19. In paragraph 17, A method for manufacturing a secondary battery, further comprising a step of combining the other surface of the above-mentioned edge portion and the above-mentioned reinforcement portion.

20. In paragraph 19, A method for manufacturing a secondary battery, wherein in the step of combining the above-mentioned frame and the above-mentioned reinforcement, heat or pressure is applied to the outer surface of the above-mentioned reinforcement.