Secondary battery manufacturing method

Abstract

The present invention relates to a secondary battery manufacturing method and, more specifically, to a method for manufacturing a chargeable / dischargeable secondary battery. The secondary battery manufacturing method according to an embodiment of the present invention may comprise: a preparation step of preparing an electrode assembly and an exterior material sheet including a metal layer; a packaging step of packaging the electrode assembly by using the exterior material sheet and a cover member; and a coupling step of coupling the cover member and the exterior sheet to each other by heating or pressing the cover member and the exterior material sheet by means of a sealing belt.

Description

Secondary battery manufacturing method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0183511, filed December 15, 2023, and Korean Patent Application No. 10-2024-0183606, filed December 11, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for manufacturing a secondary battery, and more particularly, to a method for manufacturing a secondary battery capable of being charged and discharged.

[0005] Unlike primary batteries, which are non-rechargeable, secondary batteries (rechargeable batteries) are rechargeable and dischargeable. Small secondary batteries are used in portable electronic devices such as cell phones, laptops, and camcorders, while medium- or large-sized secondary batteries are widely used as power sources for motors in hybrid vehicles and other vehicles.

[0006] Secondary batteries can be classified into various types depending on the type of outer packaging material that houses the electrode assembly. For example, secondary batteries can be classified into square secondary batteries in which the electrode assembly is housed inside a square metal can, cylindrical secondary batteries in which the electrode assembly is housed inside a cylindrical metal can, and pouch-type secondary batteries in which the electrode assembly is housed inside a pouch case.

[0007] Such a pouch-type secondary battery can be manufactured by bonding a pouch-type film in which a cup portion is formed. Fig. 1 is a drawing showing a cup portion of a pouch-type secondary battery. Fig. 1 shows a pouch film (2) pressed downward. A concave cup portion (2') is formed in the pouch film (2). At this time, the forming depth of the cup portion (2') is limited due to the material properties of the pouch film (2). Therefore, it is difficult to form the cup portion (2') sufficiently deep to increase the capacity of the secondary battery, and there is a problem that as the thickness of the pouch film (2) is reduced during the forming of the cup portion (2'), defects such as cracks are likely to occur in the cup portion (2').

[0008] Meanwhile, in the manufacturing of pouch-type secondary batteries, gases are generated internally within the secondary battery during the electrode assembly and activation processes. This internal gas must be discharged externally through a degassing process. This presents a problem: a portion of the pouch case to which the pouch film is bonded must be discarded after the degassing process.

[0009] Fig. 2 is a drawing illustrating that a portion of a pouch case is discarded after a degassing process. Fig. 2 illustrates a pouch-type secondary battery (1), a pouch case (2) comprising an outer case (2a) and a pocket portion (2b), and an electrode (3). Here, the pocket portion (2b) is removed after internal gas is discharged to the outside through the degassing process, so there has always been a problem that a portion of the pouch case (2) is discarded.

[0010] The present invention has been conceived in recognition of the above problems, and the purpose of the present invention is to provide a method for manufacturing a secondary battery that can solve problems that occur in the process of manufacturing a pouch-type secondary battery.

[0011] A method for manufacturing a secondary battery according to a first embodiment of the present invention may include a preparation step of preparing an electrode assembly and an outer sheet including a metal layer; a packaging step of packaging the electrode assembly using the outer sheet and a cover member; and a joining step of joining the cover member and the outer sheet by heating or pressurizing the cover member and the outer sheet with a sealing belt.

[0012] The packaging step may include a first packaging step of wrapping the electrode assembly with the outer material sheet so that an internal space in which the electrode assembly is accommodated and an outer material opening communicating the internal space with the outside are formed; and a second packaging step of inserting the cover member into the outer material opening.

[0013] The above-mentioned combining step may be a step of combining the cover member and the exterior sheet to seal the internal space.

[0014] The first packaging step may include: a step of positioning the electrode assembly on the upper surface of the outer sheet; a step of wrapping the electrode assembly by rolling or folding the outer sheet so that one end and the other end of the outer sheet meet each other; and a step of bonding or fusing one end and the other end of the outer sheet.

[0015] The above-mentioned joining step may be a step of joining the cover member and the exterior material sheet by heating or pressurizing the cover member and the exterior material sheet with the sealing belt including a metal wire.

[0016] The above bonding step may include a heating step of heating the sealing belt; a winding step of winding the sealing belt around the cover member and the outer material sheet; and a fusing step of tightening the sealing belt to fuse the cover member and the outer material sheet.

[0017] The above heating step and the above winding step can be performed simultaneously or sequentially.

[0018] The above heating step may be a step of heating the sealing belt by applying current to a heating wire included in the sealing belt.

[0019] The above winding step may be a step of winding the sealing belt over the entire area of ​​the outer sheet facing the cover member.

[0020] In the above fusion step, one end and the other end of the sealing belt can be pulled in different directions.

[0021] In the above fusion step, the temperature of the sealing belt can be maintained between 180 and 220°C.

[0022] The secondary battery manufacturing method according to the first embodiment of the present invention may further include an electrolyte injection step, which is performed after the bonding step and injects an electrolyte into the internal space through an electrolyte injection port formed in the cover member.

[0023] Meanwhile, in the secondary battery manufacturing method according to the second embodiment of the present invention, the second packaging step may be a step of inserting a cover member including a body part into which an electrode lead is inserted and a gasket that surrounds the body part into the outer material opening.

[0024] In the above bonding step, the gasket can be bonded to the body part and the outer sheet, respectively.

[0025] According to the secondary battery manufacturing method according to the present invention, a pouch-shaped outer material can be prepared without forming a cup portion for accommodating an electrode assembly, so that the battery capacity can be increased by increasing the size of the pouch-shaped outer material, the material and thickness of the outer material sheet for manufacturing the pouch-shaped outer material can be freely selected, and there is an advantageous effect of preventing defects such as cracks from occurring in the pouch-shaped outer material.

[0026] In addition, according to the secondary battery manufacturing method according to the present invention, the cover member and the outer material sheet are combined by heating or pressurizing the cover member and the outer material sheet with a sealing belt, which has the advantageous effect of improving the bonding strength between the cover member and the outer material sheet.

[0027] Figure 1 is a drawing showing a cup portion of a pouch-type secondary battery.

[0028] Figure 2 is a drawing to explain that a portion of the pouch case is discarded after the degassing process.

[0029] Figure 3 is a flowchart of a secondary battery manufacturing method according to the first embodiment of the present invention.

[0030] FIG. 4 is a perspective view of a secondary battery manufactured according to the secondary battery manufacturing method according to FIG. 3.

[0031] Figure 5 is an exploded perspective view of the secondary battery according to Figure 4.

[0032] Figure 6 is a flowchart showing in detail the packaging step in the secondary battery manufacturing method according to the first embodiment of the present invention.

[0033] FIG. 7 is a perspective view illustrating the bonding of a cover member and an outer sheet in a secondary battery manufacturing method according to the first embodiment of the present invention.

[0034] Fig. 8 is a cross-sectional view showing the internal structure of the sealing belt illustrated in Fig. 7.

[0035] Figure 9 is a flowchart showing in detail the bonding step in the secondary battery manufacturing method according to the first embodiment of the present invention.

[0036] FIG. 10 is a drawing for explaining how an outer sheet is bonded to a gasket in a secondary battery manufacturing method according to a second embodiment of the present invention.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Hereinafter, a method for manufacturing a secondary battery according to the present invention will be described with reference to the drawings.

[0041]

[0042] Example 1

[0043] Fig. 3 is a flowchart of a method for manufacturing a secondary battery according to a first embodiment of the present invention, and Fig. 4 is a perspective view of a secondary battery manufactured according to the method for manufacturing a secondary battery according to Fig. 3. Fig. 5 is an exploded perspective view of the secondary battery according to Fig. 4.

[0044] Referring to FIGS. 3 to 5, a method for manufacturing a secondary battery according to a first embodiment of the present invention may include a preparation step (S100) of preparing an electrode assembly (100) and an outer sheet (200a) including a metal layer; a packaging step (S200) of packaging the electrode assembly (100) using the outer sheet (200a) and the cover member (300); and a joining step (S300) of joining the cover member (300) and the outer sheet (200a) by heating or pressurizing the cover member (300) and the outer sheet (200a) with a sealing belt (400).

[0045] The secondary battery (10) manufactured according to the above manufacturing method accommodates the electrode assembly (100) inside according to the method of packaging the electrode assembly (100) using the outer material sheet (200a) and the cover member (300), so that the pouch-type outer material (200) does not have a cup portion formed therein for accommodating the electrode assembly (100). In this case, the capacity of the secondary battery (10) can be easily increased by increasing the size of the pouch-type outer material (200), and the material or thickness of the outer material sheet (200a) for manufacturing the pouch-type outer material (200) can be freely selected, and the occurrence of defects such as cracks in the pouch-type outer material (200) can be prevented.

[0046] In addition, in the case of the secondary battery (10) manufactured according to the above manufacturing method, since it has a cover member (300) and an outer sheet (200a) that are joined to each other by heating or pressurization by a sealing belt (400), the bonding strength between the cover member (300) and the outer sheet (200a) can be improved. In particular, the sealing belt (400) can effectively heat or pressurize the outer sheet (200a) that is in contact with the corner of the cover member (300), so that the outer sheet (200a) can be prevented from being separated from the corner of the cover member (300) after a certain period of time.

[0047] The electrode assembly (100) is a laminate including an anode, a cathode, and a separator, and may have various structures. For example, the electrode assembly may be a stacked electrode assembly in which the anode, the cathode, and the separator are laminated in one direction, or a stack-folded electrode assembly in which the anode, the cathode, and the separator are laminated in one direction and then folded.

[0048] Here, the positive electrode may include a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, and the negative electrode may include a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector. The separator is a membrane of an insulating material interposed between the positive electrode and the negative electrode to block contact between the positive electrode and the negative electrode, and a plurality of pores through which positive ions pass may be formed in the separator.

[0049] An electrode tab (110) may be connected to the non-conductive portion of the electrodes (positive and negative electrodes) constituting the electrode assembly (100), and the electrode tab (110) may be welded to an electrode lead (120). At this time, a part of the electrode lead (120) may be exposed to the outside of the secondary battery (10). Specifically, a part of the electrode lead (120) may pass through a through hole (330) formed in the cover member (300) and be exposed to the outside of the secondary battery (10).

[0050] The exterior sheet (200a) may be a sheet having one end (201a) and another end (202a) spaced apart from the first end (201a) in a predetermined direction. The pouch-shaped exterior sheet (200) may be formed by rolling or folding the exterior sheet (200a) so that the first end (201a) and the second end (202a) of the exterior sheet (200a) meet. At this time, the first end (201a) and the second end (202a) of the exterior sheet (200a) may be joined to each other in various ways.

[0051] One end (201a) of the exterior sheet (200a) can be joined to the inner surface or outer surface of the other end (202a). As illustrated in FIG. 5, the outer surface of one end (201a) of the exterior sheet (200a) can be joined to the inner surface of the other end (202a). Additionally, the inner surface of one end (201a) of the exterior sheet (200a) can also be joined to the inner surface of the other end (202a).

[0052] Meanwhile, the exterior sheet (200a) may be a laminate sheet including a metal layer such as aluminum or stainless steel. At this time, a resin layer may be formed on each of the outer and inner surfaces of the metal layer.

[0053] The metal layer can serve as a substrate that maintains mechanical strength and a barrier layer that prevents the infiltration of moisture and oxygen. In addition to preventing the inflow or leakage of foreign substances such as gas and moisture, the metal layer can be composed of aluminum or an aluminum alloy to enhance the strength of the battery case. Examples of aluminum alloys that can be used include alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105, and these can be used alone or in combination.

[0054] The first resin layer coated on the outer surface of the metal layer must have excellent resistance to the external environment in order to protect the electrode assembly from the outside. Therefore, the first resin layer is required to have excellent tensile strength and corrosion resistance relative to its thickness. For the first resin layer, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyolefin resin such as polyethylene or polypropylene, etc. can be used.

[0055] The second resin layer coated on the inner surface of the metal layer can be combined with a cover member (300) described later to seal the internal space (220), and the second resin layer can be composed of a polyolefin series resin. For example, CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene propylene copolymer, polyethylene and acrylic acid copolymer, and polypropylene and acrylic acid copolymer can be used for the second resin layer.

[0056] The cover member (300) can be coupled to the outer material sheet (200a) to package the electrode assembly (100). Specifically, the cover member (300) is coupled to a pouch-shaped outer material (200) formed by rolling or folding the outer material sheet (200a), and the cover member (300) can block an open outer material opening (210) formed on both sides of the pouch-shaped outer material (200). At this time, the electrode assembly (100) can be accommodated in the internal space (220) formed by the pouch-shaped outer material (200) and the cover member (300).

[0057] This internal space (220) can be filled with an electrolyte, and the cover member (300) can seal the internal space (220) to prevent the electrolyte from leaking from the internal space (220). Specifically, the cover member (300) inserted into the outer material opening (210) that connects the internal space (220) and the outside can be combined with the inner surface of the pouch-shaped outer material (200) to seal the internal space (220). Here, the inner surface of the pouch-shaped outer material (200) can be the second resin layer described above.

[0058] The length of the portion of the cover member (300) inserted into the interior of the pouch-shaped outer material (200) may vary. For example, as illustrated in FIGS. 4 and 5, only a portion of the cover member (300) may be inserted into the interior of the pouch-shaped outer material (200), and the remaining portion of the cover member (300) may be exposed to the exterior of the pouch-shaped outer material (200).

[0059] The cover member (300) may be formed of a material that is not easily permeable to moisture in order to seal the internal space (220) of the pouch-shaped outer material (200) by being combined with the inner surface of the pouch-shaped outer material (200). For example, the cover member (300) may be obtained from metal or resin, or may be obtained from a laminate sheet in which a resin layer is formed on both sides of a metal layer.

[0060] In addition, the cover member (300) may have a rectangular box shape. In this case, the four side surfaces of the cover member (300) inserted into the outer casing opening (210) face the inner surface of the pouch-shaped outer casing (200). Since all four side surfaces of the cover member (300) are formed as flat planes, the four side surfaces of the cover member (300) are firmly combined with the inner surface of the pouch-shaped outer casing (200), so that the inner space (220) of the pouch-shaped outer casing (200) can be effectively sealed.

[0061] At this time, the cover member (300) can be heat-sealed and bonded to the inner surface of the pouch-shaped outer material (200) to seal the inner space (220) of the pouch-shaped outer material (200). Specifically, the cover member (300) and the pouch-shaped outer material (200) can be heat-sealed to each other by being pressed by a high-temperature sealing belt (400). The high-temperature sealing belt (400) presses the area where the pouch-shaped outer material (200) and the cover member (300) face each other, and the pouch-shaped outer material (200) and the cover member (300) can be bonded in the pressurized area to seal the inner space (220).

[0062] The sealing belt (400) can uniformly transmit heat and pressure to the pressurized area, thereby improving the bonding strength between the pouch-shaped outer material (200) and the cover member (300). In particular, the sealing belt (400) can effectively heat and pressurize the pouch-shaped outer material (200) that is in contact with the corner of the cover member (300), thereby preventing the pouch-shaped outer material (200) from being separated from the corner of the cover member (300) after a certain period of time.

[0063] Meanwhile, Fig. 6 is a flowchart illustrating in detail a packaging step in a secondary battery manufacturing method according to a first embodiment of the present invention. Referring to Fig. 6, the packaging step (S200) may include a first packaging step (S210) of wrapping the electrode assembly (100) with an exterior material sheet (200a) so as to form an internal space (220) in which the electrode assembly (100) is accommodated and an exterior material opening (210) that connects the internal space (220) with the outside; and a second packaging step (S220) of inserting a cover member (300) into the exterior material opening (210).

[0064] The first packaging step (S210) may include a step of positioning the electrode assembly (100) on the upper surface of the outer sheet (200a); a step of wrapping the electrode assembly (100) by rolling or folding the outer sheet (200a) so that one end (201a) and the other end (202a) of the outer sheet (200a) meet each other; and a step of bonding or fusing one end (201a) and the other end (202a) of the outer sheet (200a).

[0065] Here, one end (201a) and the other end (202a) of the outer sheet (200a) can be bonded with an adhesive or heat-fused to each other by transmitting heat and pressure to form a pouch-shaped outer sheet (200). An internal space (220) for accommodating an electrode assembly (100) is provided inside the pouch-shaped outer sheet (200), and an outer sheet opening (210) can be formed at one end and the other end of the internal space (220), respectively.

[0066] Conventionally, a pouch-type secondary battery has been manufactured by forming a cup portion on a pouch film, inserting an electrode assembly into the cup portion, and then sealing the pouch film with the formed cup portion with another pouch film. However, due to the material properties of the pouch film, there was a limit to the forming depth of the cup portion, making it impossible to form the cup portion deeply to increase the capacity of the secondary battery. Furthermore, during the forming process of the cup portion, the thickness of the pouch film was reduced, which caused problems such as cracks to occur in the pouch film.

[0067] On the other hand, since the pouch-shaped outer material (200) of the secondary battery (10) according to the present invention is prepared by rolling or folding the outer material sheet (200a), the electrode assembly (100) can be accommodated in the internal space (220) of the pouch-shaped outer material (200) without a separate cup portion forming. In this case, since the conventional limitation due to the formation of the cup portion in the pouch-shaped outer material is not applied, the capacity of the secondary battery (10) can be easily increased by increasing the size of the internal space (220). In addition, since the pouch-shaped outer material (200) prepared by rolling or folding the outer material sheet (200a) does not have a portion where the thickness is reduced, the occurrence of defects such as cracks in the pouch-shaped outer material (200) can be prevented.

[0068] Meanwhile, Fig. 7 is a perspective view illustrating the joining of a cover member and an outer sheet in a secondary battery manufacturing method according to the first embodiment of the present invention. Fig. 7 illustrates a rolled or folded outer sheet (200a) and a cover member (300) inserted into the outer sheet (200a) being pressed by a sealing belt (400).

[0069] Specifically, the sealing belt (400) is wound around the area of ​​the outer sheet (200a) where the cover member (300) is inserted, and one end (401) and the other end (402) of the sealing belt (400) can be pulled in different directions. That is, the outer sheet (200a) and the cover member (300) can be pressed by the sealing belt (400).

[0070] Here, the sealing belt (400) can be maintained at a high temperature, so that the outer sheet (200a) and the cover member (300) around which the sealing belt (400) is wound can receive heat and pressure through the sealing belt (400). In this case, the outer sheet (200a) and the cover member (300) can be thermally bonded to each other to seal the internal space (220).

[0071] Fig. 8 is a cross-sectional view showing the internal structure of the sealing belt illustrated in Fig. 7. Referring to Fig. 8, the sealing belt (400) may include a metal wire (410) having a heating wire (411) provided therein. A user may apply current to the heating wire (411) to increase the temperature of the heating wire (411) and the metal wire (410) surrounding the heating wire.

[0072] Meanwhile, the above-described joining step (S300) is a step of sealing the internal space (220) by joining the cover member (300) and the exterior sheet (200a), and may be a step of joining the cover member (300) and the exterior sheet (200a) by heating and pressurizing the cover member (300) and the exterior sheet (200a) with a sealing belt (400) including a high-temperature metal wire (410).

[0073] In this case, the high-temperature sealing belt (400) uniformly presses all parts where the cover member (300) and the exterior material sheet (200a) come into contact, thereby improving the bonding strength between the cover member (300) and the exterior material sheet (200a). In particular, the high-temperature sealing belt (400) can effectively pressurize the part where the edge of the cover member (300) and the exterior material sheet (200a) come into contact, thereby effectively bonding the edge of the cover member (300) and the exterior material sheet (200a). In this case, there is an advantageous effect that the exterior material sheet (200a) does not separate from the edge of the cover member (300) even after a predetermined period of time has passed.

[0074] Meanwhile, FIG. 9 is a flowchart illustrating in detail a bonding step in a secondary battery manufacturing method according to the first embodiment of the present invention. Referring to FIG. 9, the bonding step (S300) may include a heating step (S310) of heating a sealing belt (400); a winding step (S320) of winding the sealing belt (400) around the cover member (300) and the outer sheet (200a); and a fusing step (S330) of tightening the sealing belt (400) to fuse the cover member (300) and the outer sheet (200a). Here, the heating step (S310) and the winding step (S320) may be performed simultaneously or sequentially.

[0075] The heating step (S310) may be a step of heating the sealing belt (400) by applying current to the heating wire (411) included in the sealing belt (400). Specifically, the sealing belt (400) may include a metal wire (410) having a heating wire (411), and a user may apply current to the heating wire (411) to increase the temperature of the heating wire (411) and the metal wire (410).

[0076] The winding step (S320) may be a step of winding a sealing belt (400) around the entire area of ​​the exterior sheet (200a) facing the cover member (300). Specifically, the winding step (S320) may be a step of winding a metal wire (410) around the entire area of ​​the exterior sheet (200a) where the cover member (300) is inserted.

[0077] Meanwhile, in the fusion step (S330), one end (401) and the other end (402) of the sealing belt (400) can be pulled in different directions. As a result, the portion where the sealing belt (400) is wound can receive heat and pressure, and the cover member (300) can be fused with the outer sheet (200a). Here, the process of pulling one end (401) and the other end (402) of the sealing belt (400) in different directions can be a process of pulling both ends of a high-temperature metal wire (410) in different directions using a device such as a robot arm.

[0078] In the fusing step (S330), the temperature of the sealing belt (400) can be maintained between 180 and 220°C. Specifically, one end (401) and the other end (402) of the sealing belt (400) are pulled in different directions, and while the cover member (300) and the outer sheet (200a) are fused, the temperature of the metal wire (410) included in the sealing belt (400) can be maintained between 180 and 220°C. That is, the user can continuously apply current to the heating wire (411) of the metal wire (410) during the fusing step (S330) to maintain the temperature of the metal wire (410) between 180 and 220°C.

[0079] In this case, during the fusion step (S330), the cover member (300) and the exterior sheet (200a) are pressurized at a uniform temperature, which has the advantageous effect of improving the bonding strength between the cover member (300) and the exterior sheet (200a).

[0080] Meanwhile, the secondary battery manufacturing method according to the first embodiment of the present invention may further include an electrolyte injection step (S400) that is performed after the bonding step (S300) and injects an electrolyte into the internal space (220) through an electrolyte injection port formed in the cover member (300). Here, the user may inject the electrolyte into the internal space (220) of the outer material (200) through the electrolyte injection port (340) while arranging the secondary battery (10) such that the cover member (300) in which the electrolyte injection port (340) is formed faces upward.

[0081] In addition, the secondary battery manufacturing method according to the first embodiment of the present invention may further include a degassing step, which is performed after the electrolyte injection step (S400) and discharges gas generated during activation of the secondary battery (10) to the outside through the electrolyte injection port (340). Here, the user may open the electrolyte injection port (340) to induce the discharge of gas in the internal space (220).

[0082] Conventional pouch-type secondary batteries feature a gas pocket formed by rolling a portion of the outer packaging material. The gas pocket is then removed from the outer packaging material after capturing the internal gas. Consequently, conventional batteries have been plagued by the problem of portions of the outer packaging material being repeatedly discarded.

[0083] On the other hand, the secondary battery manufacturing method according to the first embodiment of the present invention is performed after the electrolyte injection step (S400) and includes a degassing step for discharging gas from the internal space (220) to the outside, thereby solving the conventional problem of a portion of the outer material being repeatedly discarded.

[0084]

[0085] Second Example

[0086] The secondary battery manufacturing method according to the second embodiment of the present invention differs from the first embodiment in that the cover member further includes a gasket. Commonalities with the first embodiment will be omitted as much as possible, and the second embodiment will be described with a focus on differences. It should be understood that any details not described in the second embodiment, if necessary, may be considered as those described in the first embodiment.

[0087] A secondary battery manufacturing method according to a second embodiment of the present invention may include a preparation step (S100) of preparing an electrode assembly (100) and an outer material sheet (200a) including a metal layer; a packaging step (S200) of packaging the electrode assembly (100) using the outer material sheet (200a) and the cover member (300); and a joining step (S300) of joining the cover member (300) and the outer material sheet (200a) by heating and pressing them with a sealing belt (400).

[0088] Here, the packaging step (S200) may include a first packaging step (S210) of wrapping the electrode assembly (100) with an exterior material sheet (200a) so that an internal space (220) in which the electrode assembly (100) is accommodated and an exterior material opening (210) connecting the internal space (220) and the outside are formed; and a second packaging step (S220) of inserting a cover member (300) into the exterior material opening (210).

[0089] Meanwhile, Fig. 10 is a drawing for explaining how an outer sheet is coupled to a gasket in a secondary battery manufacturing method according to a second embodiment of the present invention. Referring to Fig. 10, a cover member (300) may include a body portion (310) into which an electrode lead (120) is inserted, and a gasket (320) that surrounds the body portion (310). As the cover member (300) is wrapped with the outer sheet (200a), the gasket (320) is interposed between the body portion (310) and the outer sheet (200a), and the gasket (320) and the outer sheet (200a) may be coupled using a high-temperature sealing belt (400).

[0090] Specifically, one end (401) and the other end (402) of the high-temperature sealing belt (400) can be pulled in different directions, thereby transmitting heat and pressure to the body portion (310), the gasket (320), and the outer sheet (200a). Thereafter, the gasket (320) and the body portion (310), and the gasket (320) and the outer sheet (200a) can be joined by heat fusion.

[0091] The gasket (320) is an insulator that surrounds the body portion (310) and may be composed of a resin-based material. Typically, the gasket (320) may be composed of the same material as the inner surface of the outer sheet (200a). In addition, the gasket (320) may surround only a portion of the body portion (310). As illustrated in FIG. 10, the gasket (320) may surround only the portion of the body portion (310) that comes into contact with the outer sheet (200a).

[0092] This gasket (320) is a member that surrounds the body part (310) and can prevent electrolyte leakage between the outer material (200) and the body part (310). At this time, the gasket (320) can also serve as a medium for a firm bond between the outer material (200) and the body part (310).

[0093] Additionally, the gasket (320) may have various shapes. For example, the gasket (320) may have a frame shape that surrounds a side surface of the outer surface of the body portion (310). Additionally, the gasket (320) may be formed to surround both the inner and outer surfaces of the body portion (310).

[0094] In the case of the secondary battery manufacturing method according to the second embodiment of the present invention, the cover member (300) includes a body part (310) and a gasket (320), and the second packaging step (S220) may be a step of inserting the cover member (300), which includes a body part (310) into which the electrode lead (120) is inserted, and a gasket (320) that surrounds the body part (310), into the outer material opening (210).

[0095] In addition, in the bonding step (S300) performed after the second packaging step (S220), the gasket (320) can be bonded to the body portion (310) and the outer sheet (200a), respectively, to seal the internal space (220). Specifically, the body portion (310) and the gasket (320), which have been surface-treated, are bonded by receiving heat and pressure, and the gasket (320) can be bonded to the inner surface of the outer sheet (200a) by heat fusion.

[0096] At this time, as described above, the gasket (320) may be composed of the same material as the inner surface of the outer sheet (200a). Representatively, the gasket (320) may be composed of materials such as CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene propylene copolymer, polyethylene and acrylic acid copolymer, and polypropylene and acrylic acid copolymer.

[0097]

[0098] 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.

[0099]

[0100] [Explanation of symbols]

[0101] 10: Secondary battery 100: Electrode assembly

[0102] 110: Electrode tab 120: Electrode lead

[0103] 200: Pouch-type outer material 200a: Outer material sheet

[0104] 201a: Exterior sheet end 202a: Exterior sheet end

[0105] 210: Exterior opening 220: Interior space

[0106] 300: Cover member 310: Body part

[0107] 311: Lead insert 320: Gasket

[0108] 400: Sealing belt 401: One end of the sealing belt

[0109] 402: Other end of sealing belt 410: Heating wire

[0110] S100: Preparation stage S200: Packaging stage

[0111] S210: First packaging step S220: Second packaging step

[0112] S300: Bonding stage S310: Heating stage

[0113] S320: Winding stage S330: Fusing stage

[0114] S400: Electrolyte injection stage

Claims

1. A preparatory step of preparing an electrode assembly and an outer sheet including a metal layer; A packaging step of packaging the electrode assembly using the above outer material sheet and cover member; and A secondary battery manufacturing method including a bonding step of bonding the cover member and the outer material sheet by heating or pressurizing the cover member and the outer material sheet with a sealing belt.

2. In claim 1, The above packaging steps are: A first packaging step of wrapping the electrode assembly with the outer material sheet so that an internal space in which the electrode assembly is accommodated and an outer material opening communicating the internal space with the outside are formed; and A method for manufacturing a secondary battery, characterized by including a second packaging step of inserting the cover member into the outer packaging opening.

3. In claim 2, The above combining step is, A method for manufacturing a secondary battery, characterized by comprising a step of sealing the internal space by combining the cover member and the outer sheet.

4. In claim 2, The above first packaging step is, A step of positioning the electrode assembly on the upper surface of the outer sheet; A step of wrapping the electrode assembly by rolling or folding the outer sheet so that one end and the other end of the outer sheet meet each other; and A method for manufacturing a secondary battery, characterized by including a step of bonding or fusing one end and the other end of the outer sheet.

5. In claim 1, The above combining step is, A method for manufacturing a secondary battery, characterized in that the step of combining the cover member and the outer sheet by heating or pressurizing the cover member and the outer sheet with the sealing belt including a metal wire.

6. In claim 1, The above combining step is, A heating step for heating the above sealing belt; A winding step of winding the sealing belt around the cover member and the outer sheet; and A method for manufacturing a secondary battery, characterized by including a fusing step of tightening the sealing belt to fuse the cover member and the outer material sheet.

7. In claim 6, A method for manufacturing a secondary battery, characterized in that the heating step and the winding step are performed simultaneously or sequentially.

8. In claim 6, The above heating step is, A method for manufacturing a secondary battery, characterized in that it is a step of heating the sealing belt by applying current to a heating wire included in the sealing belt.

9. In claim 6, The above winding step is, A method for manufacturing a secondary battery, characterized in that the step is to wrap the sealing belt around the entire area of ​​the outer sheet facing the cover member.

10. In claim 6, A method for manufacturing a secondary battery, characterized in that in the above-mentioned fusing step, one end and the other end of the sealing belt are pulled in different directions.

11. In claim 6, A method for manufacturing a secondary battery, characterized in that in the above fusion step, the temperature of the sealing belt is maintained between 180 and 220°C.

12. In claim 2, A method for manufacturing a secondary battery, characterized in that it further includes an electrolyte injection step of injecting an electrolyte into the internal space through an electrolyte injection port formed in the cover member, the step being performed after the above bonding step.

13. In claim 2, The second packaging step is: A method for manufacturing a secondary battery, characterized by the step of inserting a cover member including a body part into which an electrode lead is inserted and a gasket covering the body part into the opening of the outer material.

14. In claim 13, A method for manufacturing a secondary battery, characterized in that in the above bonding step, the gasket is bonded to the body part and the outer sheet, respectively.

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