Secondary battery and secondary battery manufacturing method

Abstract

A secondary battery manufacturing method according to one embodiment of the present document comprises: a first sealing step of sealing the edge of a pouch-type exterior material by forming an edge sealing part on the edge of the pouch-type exterior material having an accommodation part for accommodating an electrode assembly and a collection part for collecting gas generated during a charging / discharging process of the electrode assembly; a degassing step of discharging the gas collected in the collection part during the charging / discharging process of the electrode assembly to the outside of the pouch-type exterior material; and a second sealing step of forming a partition sealing part between the accommodation part and the collection part in the pouch-type exterior material so as to partition the accommodation part from the collection part after the degassing step. The first sealing step may be a step of further forming an additional sealing part which extends in a direction crossing between the accommodation part and the collection part in the edge sealing part and is disposed on the collection part side so as to be spaced apart from the partition sealing part.

Description

Secondary batteries and secondary battery manufacturing methods

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0121139, filed September 12, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The embodiments of this document relate to secondary batteries and methods for manufacturing secondary batteries.

[0005] In general, secondary batteries are batteries that can be recharged, unlike primary batteries that cannot be recharged, and are widely used in electronic devices such as cell phones, laptops, camcorders, and electric vehicles.

[0006] Secondary batteries can be classified into cylindrical or square batteries in which the electrode assembly is built into a cylindrical or square metal can, and pouch-type batteries in which the electrode assembly is built into a pouch-type case of a laminate sheet, depending on the shape of the battery case.

[0007] Fig. 1 is a drawing illustrating an example of a pouch-type secondary battery. The pouch-type secondary battery (1, pouch-type cell) includes an electrode assembly (2) formed by alternately stacking electrodes and separators, and a pouch-type outer case (20) in which the electrode assembly (2) is accommodated. Electrode tabs (15) may be connected to the electrodes of the electrode assembly (2), respectively. The electrode tabs (15) may be welded to each other in a predetermined region and then connected to an electrode lead (17) by welding. The outer case (20) includes a receiving portion (21; cup portion) for accommodating the electrode assembly (2). The receiving portion (21) of the outer case (20) may be formed by one or two concave-shaped portions. Fig. 1 illustrates an example of a receiving portion (21) formed by two concave-shaped portions. Such an outer case (20) may be manufactured by forming a pouch film. A sealing portion (23) is formed around the periphery of the receiving portion (21) by sealing.

[0008] Meanwhile, activation gas may be generated during the charging and discharging process of the electrode assembly to activate the secondary battery. This activation gas can increase the internal pressure of the pouch-shaped outer packaging material, concentrating stress on specific portions of the pouch-shaped outer packaging material. This can cause deformation, cracks, and wrinkles in specific portions of the pouch-shaped outer packaging material. If deformation occurs in the pouch-shaped outer packaging material, its insulating performance may also deteriorate. To address these issues, forming sealing portions at various portions of the pouch-shaped outer packaging material can be considered. However, this can lead to overlapping of the sealing portions, which can actually weaken the sealing performance of the sealing portions.

[0009] The embodiments of this document are intended to provide a secondary battery and a method for manufacturing a secondary battery, which can prevent deformation, cracks, wrinkles, etc. from occurring in a specific part of a pouch-shaped outer packaging material even when the internal pressure of the pouch-shaped outer packaging material increases due to gas generated during an activation process, thereby preventing a deterioration in the insulation performance of the pouch-shaped outer packaging material.

[0010] In addition, the embodiments of this document are intended to provide a secondary battery and a method for manufacturing a secondary battery in which deformation due to increased internal pressure does not occur in a specific part of a pouch-shaped outer packaging material, and a reduction in sealing performance due to overlapping of sealing parts does not occur.

[0011] In one example, a secondary battery manufacturing method includes a first sealing step of forming a rim sealing portion on the rim of a pouch-shaped outer packaging material having a receiving portion for receiving an electrode assembly and a collecting portion for collecting gas generated during a charge / discharge process of the electrode assembly to seal the rim of the pouch-shaped outer packaging material, a degassing step of discharging the gas collected in the collecting portion during a charge / discharge process of the electrode assembly to the outside of the pouch-shaped outer packaging material, and a second sealing step of forming a partition sealing portion between the receiving portion and the collecting portion in the pouch-shaped outer packaging material to partition the receiving portion from the collecting portion after the degassing step, wherein the first sealing step may further include a step of forming an additional sealing portion that extends from the rim sealing portion in a direction crossing between the receiving portion and the collecting portion, but is disposed on the collecting portion side and spaced apart from the partition sealing portion.

[0012] In another example, the additional seal may be positioned so as not to overlap the compartment seal.

[0013] In another example, the additional sealing portion may include a curved portion that extends from the edge sealing portion and is concavely formed in a curved shape defined by a predetermined radius from a predetermined point spaced from the additional sealing portion toward the receiving portion among the pouch-shaped outer materials.

[0014] In another example, the distance between the additional seal and the compartment seal may be greater than or equal to half the radius of the curved portion in a direction perpendicular to the extension direction of the compartment seal, and less than or equal to the radius.

[0015] In another example, when the length of the additional seal defined in the extension direction of the additional seal is E, the length of the pouch-shaped outer material defined in the direction corresponding to the extension direction of the additional seal is L, and the radius of the curved portion is R, 0.06*L - 2*R <= E <= 0.06*L can be satisfied.

[0016] In another example, the edge sealing portion may include a first horizontal portion formed in a horizontal direction orthogonal to the direction in which the electrode lead electrically connected to the electrode assembly is drawn out, a first extension portion extending from one end of the first horizontal portion closer to the collecting portion in a direction away from the first horizontal portion to beyond the receiving portion, a second extension portion extending obliquely in the outer direction of the pouch-shaped outer material from an end of the first extension portion in a direction horizontally away from the first extension portion, and a second horizontal portion extending from an end of the second extension portion in a direction horizontally away from the second extension portion.

[0017] In another example, the first extension may include an inclined extension extending inwardly of the pouch-shaped outer material from one end of the first horizontal portion in a direction horizontally away from the first horizontal portion, and a horizontal extension extending from an end of the inclined extension in a direction horizontally away from the inclined extension.

[0018] In another example, the border sealing portion may further include a third extension portion extending in an inward direction of the pouch-shaped outer material at an angle from the other end of the first horizontal portion, which is located further away from the capturing portion, in a direction horizontally away from the first horizontal portion.

[0019] In another example, the connection point of the additional seal and the border seal may be located within the first extension and the second extension.

[0020] In another example, a secondary battery includes a pouch-shaped outer case having a receiving portion for receiving an electrode assembly and a collecting portion for collecting gas generated during a charge / discharge process of the electrode assembly, a border sealing portion for sealing a border of the pouch-shaped outer case, a compartment sealing portion for sealing between the receiving portion and the collecting portion in the pouch-shaped outer case to partition the receiving portion from the collecting portion, and an additional sealing portion for sealing a predetermined area of ​​the collecting portion in the pouch-shaped outer case, wherein the additional sealing portion may extend from the border sealing portion in a direction corresponding to an extension direction of the compartment sealing portion, but may be disposed to be spaced apart from the compartment sealing portion.

[0021] In another example, the additional seal may be positioned so as not to overlap the compartment seal.

[0022] In another example, the additional sealing portion may include a curved portion that extends from the edge sealing portion and is concavely formed in a curved shape defined by a predetermined radius from a predetermined point spaced from the additional sealing portion toward the receiving portion among the pouch-shaped outer materials.

[0023] In another example, the distance between the additional seal and the compartment seal may be greater than or equal to half the radius of the curved portion in a direction perpendicular to the extension direction of the compartment seal, and less than or equal to the radius.

[0024] In another example, when the length of the additional seal defined in the extension direction of the additional seal from the edge seal is E, the length of the pouch-shaped outer material defined in the direction corresponding to the extension direction of the additional seal is L, and the radius of the curved portion is R, 0.06*L - 2*R <= E <= 0.06*L can be satisfied.

[0025] According to one embodiment of the present document, by increasing the mechanical rigidity of a pouch-shaped outer shell through an additional sealing portion, even if the internal pressure of the pouch-shaped outer shell increases due to gas generated during the activation process, problems such as deformation, cracks, and wrinkles occurring in a specific part of the pouch-shaped outer shell can be reduced or resolved, and thereby, deterioration of the insulating performance of the pouch-shaped outer shell can be prevented.

[0026] Additionally, according to one embodiment of the present document, by arranging the additional sealing portion apart from the compartment sealing portion, the problem of sealing performance deterioration due to overlapping of the sealing portions can be reduced or eliminated.

[0027] Figure 1 is a drawing illustrating an example of a pouch-type secondary battery.

[0028] Figures 2 to 6 are plan views sequentially illustrating a secondary battery manufacturing method according to Example 1 of this document.

[0029] Fig. 7 is a cross-sectional view showing the laminated structure of the pouch-shaped outer material of Fig. 2.

[0030] Figure 8 is a plan view for explaining a secondary battery according to Example 2 of this document.

[0031] 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. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0032] 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.

[0033] 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.

[0034] Example 1

[0035] Hereinafter, a method for manufacturing a secondary battery according to Example 1 of the present document will be sequentially described with reference to FIGS. 2 to 6. FIGS. 2 to 6 are plan views for sequentially describing a method for manufacturing a secondary battery according to Example 1 of the present document. As a reference, the contents of Example 1 can be equally applied to the following examples, as long as they do not conflict with each other.

[0036] Preparation of pouch-type outer material

[0037] First, a pouch-shaped outer material (110) can be prepared. The pouch-shaped outer material (110) can be prepared in the form of a single outer material sheet (120) folded. Alternatively, the pouch-shaped outer material can be prepared in the form of two outer material sheets facing each other and overlapped. FIG. 2 illustrates an example of a pouch-shaped outer material (110) in which a single outer material sheet (120) is folded along a predetermined reference line (F) (see the pouch-shaped outer material of FIG. 1).

[0038] The exterior sheet (120) may be a laminate sheet including a metal layer (121) and resin layers (122, 123) laminated thereon, as illustrated in FIG. 7. The metal layer (121) may include a layer of aluminum or a layer of stainless steel. The resin layer may include a first resin layer (122) disposed on the inner surface of the metal layer (121). The first resin layer (122) may be a layer formed of polypropylene (PP) or polyphthalamide (PPA). Since the first resin layer (122) may require high insulation and corrosion resistance, the first resin layer (122) may be formed of another resin that satisfies these requirements. The resin layer may include a second resin layer (123) disposed on the outer surface of the metal layer (121). The second resin layer (123) may be a layer formed of polyethylene terephthalate (PET). Since the second resin layer (123) may be required to secure protection and insulation of the secondary battery, the second resin layer (123) may be formed of another resin that satisfies these requirements.

[0039] The pouch-shaped outer material (110) may include a receiving portion (111) for receiving the electrode assembly (140), as illustrated in FIG. 2. The receiving portion (111) may be pre-formed in the outer material sheet (120). For example, a predetermined space for receiving the electrode assembly (140) may be formed in advance in a predetermined portion of the outer material sheet (120) by pressing the outer material sheet (120) with a punch to indent a predetermined portion of the outer material sheet (120) inward. When the outer material sheet (120) is folded along a predetermined reference line (F) while the electrode assembly (140) is received in the receiving portion (111) of the outer material sheet (120), the pouch-shaped outer material (110) of FIG. 2 (before the edge sealing portion to be described later is formed) may be prepared.

[0040] The pouch-shaped outer packaging material (110) may include a collecting portion (112) for collecting gas. Gas may be generated during the process of charging and discharging the electrode assembly (140) to activate the secondary battery. The collecting portion (112) may include a predetermined space that is provided to be connected to the receiving portion (111) to collect such gas. The predetermined space of the collecting portion (112) may be formed as a space between facing outer packaging material sheets (120) without separate molding. The collecting portion (112) may refer to a portion of the pouch-shaped outer packaging material (110) located on the right side of the receiving portion (111) in FIG. 2.

[0041] For reference, the electrode assembly (140) may be formed by alternately stacking electrodes and separators. The electrodes may include a positive electrode and a negative electrode. The electrode assembly (140) may have electrode tabs connected to the electrodes. The electrode tabs may be provided separately or may be provided as part of a current collector constituting the electrode. The electrode tabs may be welded to each other in a predetermined area and then connected to the electrode lead (141) by welding.

[0042] Sealing the edges of pouch-type outer materials

[0043] Next, as illustrated in FIG. 2, edge sealing portions (130; 131, 132) may be formed on the upper edge portion (113a) and the lower edge portion (113b) of the pouch-shaped outer packaging material (110), respectively. Through this, the upper edge portion (113a) and the lower edge portion (113b) of the pouch-shaped outer packaging material (110) may be sealed, respectively. The sealing may be performed by thermally fusing the facing resin layers (122; see FIG. 7) of the outer packaging material sheet (120), or by welding the facing metal layers (121; for this purpose, removal of the resin layer may be necessary) of the outer packaging material sheet (120). Other sealings described below may also be performed in the same manner. For reference, specific directions described in this document are relative concepts and may vary depending on the viewing direction. For example, the upper and lower sides above may be the left and right depending on the viewing direction.

[0044] In Fig. 2, the right edge portion (113c) of the pouch-shaped outer material (110) may be an open portion. This may be utilized as an opening for injecting an electrolyte, as will be described later. In Fig. 2, the left edge portion (113d) of the pouch-shaped outer material (110) is a folded portion, and thus, a edge sealing portion (130) for sealing may be unnecessary.

[0045] The upper edge sealing portion (131) formed on the upper edge portion (113a) of the pouch-shaped outer material (110) may include a first horizontal portion (131a) provided on the side from which the electrode lead (141) electrically connected to the electrode assembly (140) is drawn out. The first horizontal portion (131a) may be formed in a horizontal direction (refer to the X direction) orthogonal to the drawing direction of the electrode lead (refer to the Y direction). In this document, horizontal and orthogonal may include a case where it is generally horizontal and a case where it is generally orthogonal, respectively.

[0046] The upper edge sealing portion (131) may include a first extension portion (131b) extending in a direction away from the first horizontal portion (131a) (e.g., in the X direction in FIG. 2) from one end of the first horizontal portion (131a) that is positioned closer to the capturing portion (112). The first extension portion (131b) may extend beyond the receiving portion (111). For example, the first extension portion (131b) may extend to the right of a boundary line (C) set to correspond to the right edge of the receiving portion (111) in FIG. 2.

[0047] The first extension portion (131b) may include an inclined extension portion (131b1) that extends inclinedly from one end of the first horizontal portion (131a). The inclined extension portion (131b1) may extend inclinedly in an inward direction (e.g., a downward direction in FIG. 2) of the pouch-shaped outer material (110) with respect to a direction horizontally moving away from the first horizontal portion (131a) (see X direction). The first extension portion (131b) may include a horizontal extension portion (131b2) that extends from an end of the inclined extension portion (131b1). The horizontal extension portion (131b2) may extend horizontally moving away from the inclined extension portion (131b1) (e.g., an X direction). The first extension portion may also be formed inclinedly overall without the horizontal extension portion (131b2).

[0048] The upper edge sealing portion (131) may include a second extension portion (131c) that extends obliquely from the end of the first extension portion (131b) (the end of the horizontal extension portion in FIG. 2). The second extension portion (131c) may extend obliquely in the outward direction of the pouch-shaped outer material (110) (e.g., in the upward direction in FIG. 2) with respect to the direction horizontally moving away from the first extension portion (131b).

[0049] The upper edge sealing portion (131) may include a second horizontal portion (131d) extending from the end of the second extension portion (131c). The second horizontal portion (131d) may extend horizontally away from the second extension portion (131c). The second horizontal portion (131d) may be positioned lower than the first horizontal portion (131a).

[0050] The upper edge sealing portion (131) may include a third extension portion (131e) that extends obliquely from the other end of the first horizontal portion (131a) that is located further from the capturing portion (112). The third extension portion (131e) may extend obliquely in the inward direction of the pouch-shaped outer material (110) (e.g., the lower direction in FIG. 2) with respect to the direction horizontally away from the first horizontal portion (131a).

[0051] In the case of the pouch-shaped outer casing of the present embodiment, the outer portion of the first extension portion (131b) or the outer portion of the third extension portion (131e) of the pouch-shaped outer casing can be removed. In the space (not occupied by the pouch-shaped outer casing) secured by such removal, a predetermined component (e.g., bolt) of a module or pack in which a secondary battery is placed can be placed. Through this, the energy density of the module or pack can be improved. The manufacturing method of the present embodiment can improve the energy density of a module or pack to which a secondary battery manufactured by the present embodiment is applied, while also preventing a deterioration in the insulation performance of the pouch-shaped outer casing, as will be described later.

[0052] The lower edge sealing portion (132) formed on the lower edge portion (113b) of the pouch-shaped outer material (110) can be formed in a shape symmetrical to the upper edge sealing portion (131).

[0053] Next, the electrolyte can be injected into the inside of the pouch-shaped outer material (110). The right edge portion (113c) of the open pouch-shaped outer material (110) can be used for the injection of the electrolyte.

[0054] Next, as illustrated in FIG. 3, a right edge sealing portion (133) may be formed on the right edge portion (113c) of the pouch-shaped outer material (110). This allows the open right edge portion (113c) to be sealed. The edge sealing portion (130) of the present embodiment may include the right edge sealing portion (133) along with upper and lower edge sealing portions (131, 132).

[0055] Discharge of captured gas (degassing)

[0056] Next, during the charging and discharging process of the electrode assembly (140), the gas captured in the collecting portion (112) can be discharged to the outside of the pouch-shaped outer material (110). The electrode assembly (140) can be activated by charging and discharging the electrode assembly (140) through the electrode lead (141) exposed to the outside of the pouch-shaped outer material (110), and gas can be generated during this activation process. The generated gas can be moved from the receiving portion (111) or the like to the collecting portion (112) and captured in the collecting portion (112). In order to discharge the captured gas, a hole (H) can be formed in the pouch-shaped outer material (110) as illustrated in FIG. 4. The gas captured in the collecting portion (112) can be discharged to the outside of the pouch-shaped outer material (110) through this hole (H). To promote gas discharge, gas discharge may be carried out by placing a pouch-shaped outer material (110) inside a negative pressure chamber (not shown).

[0057] Formation of compartment seals

[0058] Next, as illustrated in FIG. 5, a compartment sealing portion (150) may be formed between the receiving portion (111) and the capturing portion (112) of the pouch-shaped outer material (110). The capturing portion (112) may be removed after degassing, but prior to such removal, it is necessary to partition the receiving portion (111) from the capturing portion (112), and for this purpose, a compartment sealing portion (150) may be formed. After the formation of the compartment sealing portion (150), if the right side of the compartment sealing portion (150) of the pouch-shaped outer material (110) is removed, a final product of a secondary battery as illustrated in FIG. 6 may be prepared.

[0059] The compartment sealing portion (150) may include a sealing portion (151) where actual sealing is performed, as illustrated in FIG. 5. The sealing portion (151) may be the portion of the compartment sealing portion (150) that is positioned furthest from the receiving portion (111). The sealing portion (151) may be formed to have a width of, for example, approximately 5 mm.

[0060] The compartment sealing portion (150) may include a bonding portion (152) arranged next to the sealing portion (151). The process of forming the sealing portion may be described as a process of melting the resin layer (122; see FIG. 7) of the pouch-shaped outer material (110) with heat and pressure and then solidifying it again. In this process, the resin layer (122) of a predetermined portion (hereinafter, the portion to be the sealing portion) of the pouch-shaped outer material (110) melts and flows to an adjacent portion of the predetermined portion, thereby forming the bonding portion (152) next to the sealing portion (151). The bonding portion (152) may be formed, for example, with a width of approximately 2 mm.

[0061] The compartment sealing portion (150) may include an unsealed portion (153) positioned next to the bonding portion (152). The unsealed portion (153) may be a portion where sealing is not performed, and thus the facing outer material sheets (120) are not attached to each other. The compartment sealing portion (150) may be folded toward the receiving portion (111) after the collection portion (112) is removed. This folding may reduce the space occupied by the secondary battery, thereby improving the volumetric energy density of the secondary battery. The unsealed portion (153) of the compartment sealing portion (150) may be a portion provided to allow folding of the compartment sealing portion (150). If folding occurs in the bonding portion (152) because the unsealed portion (153) is not sufficiently secured, a problem may occur in which the seal is damaged in the bonding portion (152) where the seal is not formed normally. The non-sealing portion (153) can be provided with a width of, for example, approximately 2 mm.

[0062] Formation of additional seals

[0063] Meanwhile, as illustrated in FIG. 2, an additional sealing portion (160) may be formed separately from the edge sealing portion (130). The additional sealing portion (160) is a sealing portion that extends from the edge sealing portion (130) and may extend in a direction crossing between the receiving portion (111) and the collecting portion (112). For example, the additional sealing portion (160) may extend in a direction that generally corresponds to the extension direction of the compartment sealing portion (150) that is formed after the formation of the additional sealing portion (160). FIG. 2 illustrates an additional sealing portion (160) that is formed in an up-down direction, which is the direction in which the electrode lead (141) is exposed. The additional sealing portion (160) may include an upper additional sealing portion (161) formed from the upper edge sealing portion (131) toward the lower edge sealing portion (132), and a lower additional sealing portion (162) formed from the lower edge sealing portion (132) toward the upper edge sealing portion (131).

[0064] The additional sealing portion (160) may be formed during the forming process of the edge sealing portion (130), or before or after the forming process of the edge sealing portion (130). The additional sealing portion (160) may extend directly from the edge sealing portion (130), as illustrated in FIG. 2, or may extend spaced apart from the edge sealing portion (130). When the additional sealing portion (160) extends directly from the edge sealing portion (130), the connection point between the additional sealing portion (160) and the edge sealing portion (130) may be located within the first extension portion (131b) and the second extension portion (131c). For example, the connection point may be located within the first extension portion (131b), the second extension portion (131c), or may span across them. In Fig. 5, a connection point is located across the horizontal extension (131b2) of the first extension (131b) and the second extension (131c).

[0065] The gas generated during the activation process may increase the internal pressure of the pouch-shaped outer casing (110), thereby concentrating stress on a specific portion of the pouch-shaped outer casing (110). This may cause deformation, cracks, wrinkles, etc. to occur in a specific portion of the pouch-shaped outer casing (110). The manufacturing method of the present embodiment can reduce or resolve the occurrence of the above-mentioned problem by forming an additional sealing portion (160) between the receiving portion (111) and the collecting portion (112) to increase the mechanical rigidity of the pouch-shaped outer casing (110). If deformation, etc. does not occur in the pouch-shaped outer casing (110), a deterioration in insulation performance caused by deformation, etc. may not occur.

[0066] Meanwhile, the additional sealing member (160) may be positioned apart from the compartment sealing member (150) as illustrated in FIG. 5 (see distance D). Overlapping of the sealing members may actually result in a deterioration of sealing performance. For example, if heat and pressure are applied again to a portion that has been initially sealed by applying heat and pressure, the initial sealing may be weakened by the subsequent heat and pressure. In the present embodiment, to prevent such a problem, the additional sealing member (160) may be positioned apart from the compartment sealing member (150).

[0067] The additional sealing portion (160) may be placed on the side of the capturing portion (112) of the pouch-shaped outer material (110), for example, on the right side of the receiving portion (111) in FIG. 5.

[0068] The additional seal (160) may be spaced apart from the receiving portion (111) by, for example, approximately 11 mm in the X direction of FIG. 5. The width of the additional seal (160) (which may be defined in the X direction of FIG. 5) may be, for example, approximately 10 mm. The length of the additional seal (160) (see E of FIG. 5) may be, for example, approximately 15 mm. Approximately 8.5 mm or approximately 2.5 mm may also be considered as the length of the additional seal (160).

[0069] Meanwhile, the additional sealing portion (160) may include a curved portion (163) extending from the edge sealing portion (130) as illustrated in FIG. 2. The curved portion (163) may be a portion formed concavely in a curved shape defined by a predetermined radius (R) from a predetermined point (P) in the pouch-shaped outer material (110). The predetermined point (P) may be any point in the pouch-shaped outer material (110) and may be a predetermined point spaced apart from the additional sealing portion (160) toward the receiving portion (111). FIG. 2 illustrates an example of a curved portion (163) defined as a quadrant drawn with the predetermined point (P) as its center.

[0070] If the additional sealing portion (160) does not include a curved portion (163) and extends vertically from the edge sealing portion (130), when the internal pressure of the pouch-shaped outer packaging material (110) increases due to gas generated during the activation process, stress may be concentrated in the vertical portion, which may cause damage to the sealing portion or the pouch-shaped outer packaging material (110). In addition, in order to form the vertical portion, the sealing tool also needs to be formed vertically, but the vertical portion of the sealing tool may damage the pouch-shaped outer packaging material (110) due to its sharp shape. To prevent the occurrence of such problems, the additional sealing portion (160) in the present embodiment may include a curved portion (163).

[0071] Hereinafter, a description will be made with reference to FIG. 5. The additional sealing portion (160) is mainly intended to suppress deformation, etc., from occurring on the receiving portion (111) side of the pouch-shaped outer material (110), and therefore may be positioned adjacent to the receiving portion (111). However, if the additional sealing portion (160) is positioned too adjacent to the receiving portion (111), a problem of overlapping with the compartment sealing portion (150) may occur. In addition, if the additional sealing portion (160) is positioned too adjacent to the receiving portion (111), the passage formed between the additional sealing portion (160) and the receiving portion (111) becomes too narrow, and thus, the gas generated during the activation process may cause damage to the sealing portion while moving to the collecting portion (112).

[0072] Considering these points, the distance (D) between the additional sealing portion (160) and the compartment sealing portion (150) may be greater than or equal to half the radius (R) of the curved portion (163) and less than or equal to the radius (R). When the distance between the additional sealing portion (160) and the compartment sealing portion (150) is D and the radius of the curved portion (163) is R, R / 2 <= D <= R may be satisfied. For example, when R is 4 mm, the minimum value of D may be 2 mm.

[0073] When the separation distance D is R / 2, some overlap (see the shaded area A) may occur between the additional seal (160) and the compartment seal (150), as illustrated in FIG. 5. However, it has been experimentally confirmed that the overlapping area is very narrow and thus rarely causes problems. In addition, when the separation distance D is greater than R, the additional seal (160) may be too far from the receiving portion (111), thereby hindering the effect of suppressing deformation, etc., of the receiving portion (111). For reference, the separation distance (D) between the additional seal (160) and the compartment seal (150) may be measured in a direction orthogonal to the extension direction (the X direction in FIG. 5) when the additional seal (160) and the compartment seal (150) extend in the same direction.

[0074] In FIG. 5, the additional sealing portion (160) and the compartment sealing portion (150) are shown to overlap to some extent, but the additional sealing portion (160) may be positioned so as not to overlap the compartment sealing portion (150) at all.

[0075] Meanwhile, when the length of the additional sealing portion (160) is E, the length of the pouch-shaped outer material (110) is L, and the radius (R) of the curved portion (163) of the additional sealing portion (160) is R, 0.06*L - 2*R <= E <= 0.06*L can be satisfied. The length (E) of the additional sealing portion (160) can be defined in the extension direction of the additional sealing portion (160) (see the vertical direction of FIG. 5). And the length (E) of the additional sealing portion (160) can be measured from the side adjacent to the compartment sealing portion (150). The length (L) of the pouch-shaped outer material (110) can be defined in a direction corresponding to the extension direction of the additional sealing portion (160). In FIG. 5, the length of the pouch-shaped outer material (110) can be defined in the vertical direction in which the electrode lead (141) is exposed.

[0076] In order to suppress deformation, etc., in the receiving portion (111), the longer the length of the additional sealing portion (160) may be advantageous. However, if the length of the additional sealing portion (160) is too long, the gas generated during the activation process may be prevented from moving from the receiving portion (111) to the collecting portion (112). The length of the additional sealing portion (160) may be determined by considering these points. If the length of the additional sealing portion (160) is less than '0.06*L - 2*R', the effect of suppressing deformation, etc., in the receiving portion (111) may be impaired. If the length of the additional sealing portion (160) is greater than '0.06*L', the gas may be prevented from moving to the collecting portion (112).

[0077] secondary batteries

[0078] By manufacturing a secondary battery through the processes described above, a secondary battery (intermediate product) as shown in FIG. 5 can be manufactured. The secondary battery of FIG. 5 may include a pouch-shaped outer material (110) having a receiving portion (111) and a collecting portion (112), a border sealing portion (130) for sealing the border of the pouch-shaped outer material (110), a compartment sealing portion (150) for sealing between the receiving portion (111) and the collecting portion (112) in the pouch-shaped outer material (110), and an additional sealing portion (160) for sealing a predetermined area of ​​the collecting portion (112) in the pouch-shaped outer material (110). The additional sealing portion (160) may extend from the border sealing portion (130) in a direction corresponding to the extension direction of the compartment sealing portion (150), but may be disposed to be spaced apart from the compartment sealing portion (150). The portion located on the collecting portion (112) of the compartment sealing portion (150) of the pouch-shaped outer material (110) can be removed after the degassing process. Through this, a secondary battery (final product) as shown in FIG. 6 can be manufactured.

[0079] Example 2

[0080] Figure 8 is a plan view illustrating a secondary battery (intermediate product) according to Example 2 of this document. Since the secondary battery according to this Example differs from the secondary battery of Example 1 in the shape of the edge seal, the following description will focus on this. Note that the contents of Example 2 can be equally applied to the aforementioned Examples, as long as they do not conflict with each other.

[0081] The secondary battery according to the present embodiment includes a linearly formed edge sealing portion (230) as illustrated in FIG. 8. The upper and lower edge sealing portions (231, 232) of FIG. 8 may be linearly formed in a direction orthogonal to the vertical direction in which the electrode lead (141) is exposed. The right edge sealing portion (233) may be linearly formed in the vertical direction.

[0082] The secondary battery manufacturing method of Example 1 can be applied regardless of the shape of the edge sealing portion. For example, the manufacturing method of Example 1 can also be applied to the process of manufacturing the secondary battery of FIG. 8.

[0083] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0084] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0085] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A first sealing step of sealing the edge of a pouch-shaped outer material by forming a edge sealing portion on the edge of the pouch-shaped outer material, the pouch-shaped outer material having a receiving portion for receiving an electrode assembly and a collecting portion for collecting gas generated during a charging and discharging process of the electrode assembly; A degassing step for discharging the gas captured in the capturing portion during the charging / discharging process of the electrode assembly to the outside of the pouch-shaped outer material; and A second sealing step is included to form a partition sealing portion between the receiving portion and the capturing portion among the pouch-shaped outer materials to partition the receiving portion from the capturing portion after the degassing step. The above first sealing step is, A method for manufacturing a secondary battery, comprising the step of further forming an additional sealing portion extending in a direction crossing between the receiving portion and the capturing portion in the above-mentioned border sealing portion, but positioned on the capturing portion side so as to be spaced apart from the compartment sealing portion.

2. In claim 1, The above additional sealing part is, A method for manufacturing a secondary battery, wherein the secondary battery is arranged so as not to overlap with the above-mentioned compartment sealing portion.

3. In claim 1, The above additional sealing part is, A method for manufacturing a secondary battery, comprising a curved portion formed concavely in a curved shape defined by a predetermined radius from a predetermined point spaced from the additional sealing portion of the pouch-shaped outer material toward the receiving portion, extending from the above-mentioned edge sealing portion.

4. In claim 3, The distance between the above additional seal and the above compartment seal is, A secondary battery manufacturing method, wherein the radius of the curved portion is more than half of the radius in a direction perpendicular to the extension direction of the compartment sealing portion, and is less than or equal to the radius.

5. In claim 3, A method for manufacturing a secondary battery, wherein the length of the additional sealing portion defined in the extension direction of the additional sealing portion is E, the length of the pouch-shaped outer packaging material defined in a direction corresponding to the extension direction of the additional sealing portion is L, and the radius of the curved portion is R, satisfies 0.06*L - 2*R <= E <= 0.06*L.

6. In claim 1, The above border sealing part is, A first horizontal portion formed in a horizontal direction perpendicular to the direction in which the electrode lead is drawn out and electrically connected to the electrode assembly; A first extension portion extending from one end of the first horizontal portion closer to the capturing portion in a direction away from the first horizontal portion to beyond the receiving portion; A second extension extending from the end of the first extension to the outside of the pouch-shaped outer material in a direction horizontally away from the first extension; and A method for manufacturing a secondary battery, comprising a second horizontal portion extending horizontally away from the second extension portion from an end of the second extension portion.

7. In claim 6, The above first extension part is, An inclined extension extending in an inclined direction inwardly of the pouch-shaped outer material from the one end of the first horizontal portion in a direction horizontally away from the first horizontal portion; and A method for manufacturing a secondary battery, comprising a horizontal extension extending horizontally away from the inclined extension from the end of the inclined extension.

8. In claim 6, The above border sealing part is, A secondary battery manufacturing method further comprising a third extension portion extending in an inward direction of the pouch-shaped outer material at an angle from the other end of the first horizontal portion, which is located further from the capturing portion, in a direction horizontally away from the first horizontal portion.

9. In claim 6, The connection point between the above additional seal and the above border seal is, A method for manufacturing a secondary battery, the method comprising: positioning the first extension portion and the second extension portion.

10. A pouch-shaped outer material having a receiving portion for receiving an electrode assembly and a collecting portion for collecting gas generated during a charging and discharging process of the electrode assembly; A border sealing portion for sealing the border of the above pouch-shaped outer material; A partition sealing portion that seals between the receiving portion and the capturing portion among the pouch-shaped outer materials to separate the receiving portion from the capturing portion; and Including an additional sealing part that seals a predetermined area of ​​the capturing part among the above pouch-shaped outer materials, The above additional sealing part is, A secondary battery that extends in a direction corresponding to the extension direction of the compartment seal from the above-mentioned border seal, but is positioned apart from the compartment seal.

11. In claim 10, The above additional sealing part is, A secondary battery arranged so as not to overlap with the above compartment seal.

12. In claim 10, The above additional sealing part is, A secondary battery including a curved portion that extends from the above-mentioned edge sealing portion and is concavely formed in a curved shape defined by a predetermined radius from a predetermined point spaced apart from the additional sealing portion of the pouch-shaped outer material toward the receiving portion.

13. In claim 12, The distance between the above additional seal and the above compartment seal is, A secondary battery, wherein the radius of the curved portion is more than half of the radius in a direction perpendicular to the extension direction of the compartment sealing portion, and is less than or equal to the radius.

14. In claim 12, A secondary battery, wherein the length of the additional seal defined in the extension direction of the additional seal from the edge seal is E, the length of the pouch-shaped outer packaging material defined in the direction corresponding to the extension direction of the additional seal is L, and the radius of the curved portion is R, satisfies 0.06*L - 2*R <= E <= 0.06*L.

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