Secondary battery manufacturing system and method for manufacturing secondary battery

Abstract

According to an exemplary embodiment, a method for manufacturing a secondary battery is provided. The manufacturing method may comprise the steps of: aligning a bottom pouch and a lead pouch, wherein each of the bottom pouch and the lead pouch includes a sealant layer, a protective layer, and a metal layer between the sealant layer and the protective layer, and the sealant layer of the bottom pouch is aligned to face the sealant layer of the lead pouch; and irradiating a first sealing portion of the bottom pouch and the lead pouch with a laser beam. The wavelength of the laser beam may be in the range of 0.01 to 0.1 µm or in the range of 0.8 to 1.0 µm.

Description

Secondary battery manufacturing device and method for manufacturing a secondary battery

[0001] The present invention relates to an apparatus for manufacturing a secondary battery and a method for manufacturing a secondary battery.

[0002] The present application claims priority based on Korean Patent Application No. 10-2024-0168422 filed on November 22, 2024, which is incorporated herein by reference in its entirety.

[0003]

[0004] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as handsets, laptops, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has decreased dramatically due to improved energy density and economies of scale, and as the driving range of BEVs (battery electric vehicles) has increased to a level equivalent to that of fuel vehicles, the primary applications of secondary batteries are expanding from mobile devices to mobility.

[0005] The trend in the technological development of secondary batteries is the improvement of energy density. Here, the energy density of a secondary battery is the value obtained by dividing the maximum electrical energy that the secondary battery can store by the mass or volume of the secondary battery. Various studies are being conducted to develop batteries that are thin, light, and have high energy density.

[0006] One of the methods to increase energy density is the pouch battery. Pouch batteries can increase energy density by reducing voids through the stacking of a positive electrode, separator, and negative electrode in layers within an aluminum foil pouch.

[0007]

[0008] [Prior Art Literature]

[0009] (Patent Document 0001) Korean Published Patent No. 10-2024-0010354

[0010]

[0011] The problem that the technical concept of the present invention aims to solve is to provide an apparatus and method for rapidly and uniformly sealing a pouch-type secondary battery.

[0012]

[0013] According to exemplary embodiments of the present invention for solving the above-described problem, a method for manufacturing a secondary battery is provided. The manufacturing method may include the step of aligning a bottom pouch and a lead pouch, wherein each of the bottom pouch and the lead pouch comprises a sealant layer, a protective layer, and a metal layer between the sealant layer and the protective layer, and the sealant layer of the bottom pouch is aligned to face the sealant layer of the lead pouch; and the step of irradiating a laser beam onto a first sealing portion of the bottom pouch and the lead pouch. The wavelength of the laser beam may be in the range of 0.01 μm to 0.1 μm or, in the range of 0.8 μm to 1.0 μm.

[0014] The absorption rate of the laser beam by the metal layer of the bottom pouch may be higher than the absorption rate of the laser beam by the protective layer of the bottom pouch. The absorption rate of the laser beam by the metal layer of the lead pouch may be higher than the absorption rate of the laser beam by the protective layer of the lead pouch.

[0015] In the step of irradiating a laser beam onto the first sealing portion, the sealant layer of the bottom pouch and the sealant layer of the lead pouch can each be melted.

[0016] In the step of irradiating a laser beam onto the first sealing portion, the metal layer of the bottom pouch may be heated above the melting temperature of the sealant layer of the bottom pouch, and the metal layer of the lead pouch may be heated above the melting temperature of the sealant layer of the lead pouch.

[0017] The metal layer of the bottom pouch and the metal layer of the lid pouch, respectively, may each comprise aluminum. The sealant layer of the bottom pouch and the sealant layer of the lid pouch, respectively, may each comprise polypropylene.

[0018] The step of irradiating the first sealing part with a laser beam can be performed for a time of 0.5 seconds or more and 1 second or less.

[0019] After the step of irradiating a laser beam onto the first sealing part, the method may further include the step of applying pressure to the first sealing part.

[0020] After the step of applying pressure to the first sealing portion, the method may further include the step of injecting an electrolyte into the receiving space of the electrode assembly between the bottom pouch and the lead pouch; and the step of sealing the second sealing portion of the bottom pouch and the lead pouch.

[0021] The first sealing portion may overlap with the electrode leads of the electrode assembly. The second sealing portion may not overlap with the electrode leads of the electrode assembly.

[0022] The melting temperature of the protective layer of the bottom pouch may be higher than the melting temperature of the sealant layer of the bottom pouch. The melting temperature of the protective layer of the lead pouch may be higher than the melting temperature of the sealant layer of the lead pouch.

[0023] According to exemplary embodiments of the present invention for solving the above-described problem, a manufacturing apparatus for a secondary battery is provided. The manufacturing apparatus may include: a laser beam unit configured to irradiate a laser beam onto a sealing portion in which a first metal layer, a first sealant layer, a second sealant layer, and a second metal layer are sequentially stacked; and a press unit configured to apply pressure to the sealing portion. The wavelength of the laser beam may be in the range of 0.01 μm to 0.1 μm, or in the range of 0.8 μm to 1.0 μm.

[0024] The laser beam unit may be configured to irradiate the sealing portion with a laser for a period of time of 0.5 seconds or more and 1 second or less.

[0025] Each of the first metal layer and the second metal layer may include aluminum.

[0026] The absorption rate of the laser beam in the first metal layer may be greater than the absorption rate of the laser beam in the first sealant layer. The absorption rate of the laser beam in the second metal layer may be greater than the absorption rate of the laser beam in the second sealant layer.

[0027]

[0028] According to exemplary embodiments of the present invention, by irradiating a laser beam of a wavelength range that selectively heats a metal layer in the sealing portion of a pouch-type secondary battery, the pouch can be sealed quickly and uniformly.

[0029] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0030]

[0031] FIG. 1 is a perspective view showing a pouch-type secondary battery according to exemplary embodiments.

[0032] FIG. 2 is a cross-sectional view showing a pouch-type secondary battery according to exemplary embodiments.

[0033] FIG. 3 is a cross-sectional view showing a secondary battery manufacturing apparatus according to exemplary embodiments.

[0034] FIG. 4 is a cross-sectional view showing a secondary battery manufacturing apparatus according to exemplary embodiments.

[0035] FIG. 5 is a flowchart illustrating a method for manufacturing a secondary battery according to exemplary embodiments.

[0036]

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0038] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0039] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0040] Since embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. Accordingly, the size or proportion of each component does not entirely reflect the actual size or proportion.

[0041]

[0042] (1st embodiment)

[0043] FIG. 1 is a perspective view showing a pouch-type secondary battery (PC). FIG. 2 is a cross-sectional view showing a pouch-type secondary battery (PC).

[0044]

[0045] First, referring to FIGS. 1 and 2, a pouch-type secondary battery (PC) may include a pouch (PP) and an electrode assembly (EA) housed inside the pouch (PP). The pouch (PP) may be divided into a bottom pouch (BP) and a lead pouch (LP) based on a fold line (FL).

[0046] The bottom pouch (BP) may include a sealant layer (BI), a metal layer (BM), and a protective layer (BO). The metal layer (BM) may be interposed between the sealant layer (BI) and the protective layer (BO). The sealant layer (BI) may be located between the electrode assembly (EA) and the metal layer (BM).

[0047] According to exemplary embodiments, the metal layer (BM) may include a metal such as aluminum. The metal layer (BM) may be a substrate for forming a bottom pouch (BP). A pouch roll may be formed by applying a sealant layer and a protective layer onto a metal sheet and then winding it into a roll. A bottom pouch (BP) may be provided by separating the pouch roll according to specifications and performing a pouch forming process. The protective layer (BO) may provide oxygen and moisture barrier performance, mechanical robustness, and corrosion resistance to the bottom pouch (BP).

[0048] The sealant layer (BI) may be a component for sealing the bottom pouch (BP) and the lid pouch (LP). The sealant layer (BI) may comprise a thermoplastic material. According to exemplary embodiments, the sealant layer (BI) may have a melting temperature of about 120°C or higher and about 190°C or lower. According to exemplary embodiments, the sealant layer (BI) may comprise either polypropylene (PP) or polyethylene (PE). According to exemplary embodiments, the sealant layer (BI) may comprise cast polypropylene (CPP).

[0049] The protective layer (BO) may be an insulating layer that electrically insulates the pouch-type secondary battery (PC). The protective layer (BO) may include an insulating material. According to exemplary embodiments, the protective layer (BO) may include any one of polypropylene (PP), polyamide (PA), polyethylene (PE), polyimide (PI), and polyethylene terephthalate (PET). The protective layer (BO) may have a melting temperature higher than the melting temperature of the sealant layer (BI).

[0050]

[0051] The lead pouch (LP) may include a sealant layer (LI), a metal layer (LM), and a protective layer (LO). The metal layer (LM) may be interposed between the sealant layer (LI) and the protective layer (LO). The sealant layer (LI) may be located between the electrode assembly (EA) and the metal layer (LM).

[0052] According to exemplary embodiments, the metal layer (LM) may include a metal such as aluminum. The metal layer (LM) may be a substrate for forming a lead pouch (LP). A pouch roll may be formed by applying a sealant layer and a protective layer onto a metal sheet and then winding it into a roll. A lead pouch (LP) may be provided by separating the pouch roll according to specifications and performing a pouch forming process. The protective layer (LO) may provide oxygen and moisture barrier performance, mechanical robustness, and corrosion resistance to the lead pouch (LP).

[0053] The sealant layer (LI) may be a component for sealing the bottom pouch (BP) and the lid pouch (LP). The sealant layer (LI) may comprise a thermoplastic material. According to exemplary embodiments, the sealant layer (LI) may have a melting temperature of about 120°C or higher and about 190°C or lower. According to exemplary embodiments, the sealant layer (LI) may comprise either polypropylene (PP) or polyethylene (PE). According to exemplary embodiments, the sealant layer (LI) may comprise cast polypropylene (CPP).

[0054] The protective layer (LO) may be an insulating layer that electrically insulates the pouch-type secondary battery (PC). The protective layer (LO) may include an insulating material. According to exemplary embodiments, the protective layer (LO) may include any one of polypropylene (PP), polyamide (PA), polyethylene (PE), polyimide (PI), and polyethylene terephthalate (PET). The protective layer (LO) may have a melting temperature higher than the melting temperature of the sealant layer (LI).

[0055]

[0056] The pouch (PP) may include sealing portions (SS1, SS2) where the sealant layer (BI) of the bottom pouch (BP) and the sealant layer (LI) of the lid pouch (LP) are sealed. Before the sealing of the pouch (PP) is completed, the sealing portions (SS1, SS2) may refer to the portions scheduled to be sealed in the bottom pouch (BP) and the lid pouch (LP), respectively. After the sealing of the pouch (PP) is completed, the sealing portions (SS1, SS2) may refer to the sealed portions in the bottom pouch (BP) and the lid pouch (LP).

[0057] Sealing portions (SS1, SS2) may extend along the circumferential direction of the pouch (PP). Sealing portions (SS1, SS2) may be formed on the edge portions excluding the folded portions of the pouch (PP). Sealing portion (SS1) may be formed on the edge portions on both sides where the electrode leads (LD1, LD2) of the electrode assembly (EA) protrude. Sealing portion (SS1) may overlap with the electrode leads (LD1, LD2) in the Z direction. Sealing portion (SS2) may be formed on the edge portion on one side where the electrode leads (LD1, LD2) of the electrode assembly (EA) do not protrude. Sealing portion (SS2) may not overlap with the electrode leads (LD1, LD2) in the Z direction.

[0058]

[0059] The electrode assembly (EA) may include an anode, a cathode, and a separator interposed between the anode and the cathode. According to exemplary embodiments, the electrode assembly (EA) includes a plurality of anodes, a plurality of cathodes, and a plurality of separators interposed between them, which are stacked sequentially.

[0060] The positive electrode may include a positive current collector and a positive active material layer coated on the positive current collector. According to exemplary embodiments, the positive current collector may be aluminum foil. According to exemplary embodiments, the positive active material layer may be LiCoO2, LiNiO2, LiNi 1-x Co xO2(0.2≤x≤0.5), LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, LiNi 0.5 Mn 0.5 O2, LiMn2O4, LiMn 2-x M x It may include any one of O4 (M is Al or Li, etc.) and LiFePO4.

[0061] The cathode may include a cathode current collector and a layer of cathode active material coated on the cathode current collector. According to exemplary embodiments, the cathode current collector may be a copper foil or a nickel foil. According to exemplary embodiments, the cathode active material may include any one of lithium metal, graphite, coke, silicon, and tin.

[0062] The separator can physically block contact between the anode and the cathode. According to exemplary embodiments, the separator may comprise any one of polyethylene, polypropylene, polyolefin, PVdF (polyvinylidene fluoride), and inorganic nanoparticles (SiO2, TiO2, Al2O3, ZrO2, etc.).

[0063] The electrode assembly (EA) may include electrode leads (LD1, LD2). Each electrode lead (LD1, LD2) may be disposed at both ends of the electrode assembly (EA). Each electrode lead (LD1, LD2) may protrude outward from the pouch (PP). The electrode leads (LD1, LD2) can transmit electrical energy generated inside the pouch-type secondary battery (PC) to an external circuit. The electrode lead (LD1) may be a positive lead, and the electrode lead (LD2) may be a negative lead. According to exemplary embodiments, the electrode lead (LD1) may be nickel-plated aluminum. According to exemplary embodiments, the electrode lead (LD2) may be nickel-plated copper.

[0064]

[0065] Hereinafter, a secondary battery manufacturing apparatus (100) for manufacturing the pouch-type secondary battery (PC) of FIGS. 1 and FIG. 2 will be described.

[0066] FIGS. 3 and FIGS. 4 are drawings showing processing by a secondary battery manufacturing apparatus (100) according to exemplary embodiments.

[0067]

[0068] Referring to FIGS. 1 to 4 together, the secondary battery manufacturing device (100) may include a laser beam unit (101) and a press unit (102). The laser beam unit (101) and the press unit (102) may be components for sealing a sealing portion (SS1) of a pouch-type secondary battery (PC).

[0069] The laser beam unit (101) may be configured to irradiate a laser beam onto a sealing portion (SS1). The laser beam unit (101) may include an upper laser beam unit (101T) and a lower laser beam unit (101B). The lower laser beam unit (101B) may be configured to irradiate a laser beam (LB) onto a bottom pouch (BP). The laser beam (LB) may be incident on a metal layer (BM) through a protective layer (BO). The upper laser beam unit (101T) may be configured to irradiate a laser beam (LT) onto a lead pouch (LP). The laser beam (LT) may be incident on a metal layer (LM) through a protective layer (LO).

[0070] The laser beam unit (101) may be configured to evenly distribute the laser beam to the sealing portion (SS1). According to exemplary embodiments, the lower laser beam unit (101B) and the upper laser beam unit (101T) may each include a laser source, a scanner, and an aperture. The laser source may be configured to generate a laser beam. The scanner may be configured to control the path of the laser beam. The scanner may include a motor and a mirror. The mirror of the scanner may be configured to change the path of the laser beam or to reflect the laser beam in various directions. According to exemplary embodiments, the scanner may include a mirror extending along the extension direction (Y direction) of the first sealing portion (SS1). The aperture may be configured to evenly distribute the laser beam to the sealing portion (SS1). According to exemplary embodiments, the aperture may have a slit shape extending along the extension direction (Y direction) of the first sealing portion (SS1).

[0071] The laser beam (LB) may have a wavelength range capable of selectively heating the metal layer (BM). The absorption rate of the laser beam (LB) of the metal layer (BM) may be higher than the absorption rate of the laser beam (LB) of the protective layer (BO). The sealant layer (BI) on the metal layer (BM) may be melted by the metal layer (BM) of the bottom pouch (BP) heated by the lower laser beam device (101B).

[0072] The laser beam (LT) may have a wavelength range capable of selectively heating the metal layer (LM). The absorption rate of the laser beam (LT) of the metal layer (LM) may be higher than the absorption rate of the laser beam (LT) of the protective layer (LO). The sealant layer (LI) on the metal layer (LM) of the lead pouch (LP), heated by the upper laser beam device (101T), may be melted. The melted sealant layers (BI, LI) of the sealing portion (SS1) may be sealed.

[0073] According to exemplary embodiments, the metal layers (BM, LM) may each comprise aluminum. Aluminum exhibits a relatively high laser beam absorption rate when irradiated with a laser beam in the wavelength range of about 0.01 μm to about 0.1 μm, or in the wavelength range of about 0.8 μm to about 1.0 μm. The lower laser beam device (101B) and the upper laser beam device (101T) may each be configured to irradiate a laser beam in the wavelength range of about 0.01 μm to about 0.1 μm, or in the wavelength range of about 0.8 μm to about 1.0 μm. When irradiating with a laser in the wavelength range described above, the metal layers (BM, LM) may be selectively heated to melt the sealant layers (BI, LI). That is, since the step of heating the outer layers (BO, LO) with low thermal conductivity to conduct heat to the metal layers (BM, LM) and sealant layers (BI, LI) is omitted, the speed of the packaging process of the secondary battery can be improved.

[0074] According to exemplary embodiments, the laser beam unit (101) may be configured to irradiate a laser onto the first sealing portion (SS1) for a time of about 0.5 seconds to about 1 second. During the laser irradiation of the laser beam unit (101), the sealant layers (BI, LI) may be melted by the heated metal layers (BM, LM).

[0075] In contrast, when heat is applied to the sealing portion (SS1) with a heater, the thermal energy from the heater is conducted in the order of the protective layers (BO, LO), metal layers (BM, LM), and sealant layers (BI, LI), so it may take a longer time (e.g., more than 2 seconds) to melt the sealant layers (LI, BI). Additionally, the electrode leads (LD1, LD2), which have a higher thermal conductivity than the sealant layers (LI, BI), absorb heat, which can hinder heat conduction to the sealant layers (BI, LI) and cause an uneven heat distribution within the sealing portion (SS1). As a result, a problem may arise where the quality of the sealing becomes uneven.

[0076] A laser beam unit (101) according to exemplary embodiments of the present invention selectively heats metal layers (BM, LM), thereby preventing a rapid temperature rise of electrode leads (LD1, LD2). The absorption rate of the laser beam (LT, LB) of the electrode leads (LD1, LD2) may be smaller than the absorption rate of the laser beam (LT, LB) of the metal layers (BM, LM). Accordingly, uneven heat distribution within the sealing portion (SS1) can be prevented.

[0077] A laser beam unit (101) may be configured to heat each of the metal layers (BM, LM) to a predetermined temperature. The predetermined temperature may be above the melting temperature of the sealant layer (BI) and above the melting temperature of the sealant layer (LI). According to exemplary embodiments, the predetermined temperature may be about 120°C or higher. According to exemplary embodiments, the predetermined temperature may be about 130°C or higher. According to exemplary embodiments, the predetermined temperature may be about 140°C or higher. According to exemplary embodiments, the predetermined temperature may be about 190°C or lower. According to exemplary embodiments, the predetermined temperature may be about 180°C or lower. According to exemplary embodiments, the predetermined temperature may be about 170°C or lower.

[0078] The lower laser beam device (101B) may be configured to heat the metal layer (BM) of the bottom pouch (BP) to a temperature above the melting temperature of the sealant layer (BI). The upper laser beam device (101T) may be configured to heat the metal layer (LM) of the lead pouch (LP) to a temperature above the melting temperature of the sealant layer (LI).

[0079]

[0080] The press unit (102) may be configured to process a pouch-type secondary battery (PC) processed by the laser beam unit (101). The press unit (102) may be configured to apply pressure to the sealing portion (SS1). The laser beam unit (101) and the press unit (102) may be configured to perform operations on the pouch-type secondary battery (PC) continuously. According to exemplary embodiments, the laser beam unit (101) and the press unit (102) may be integrated into a single module. According to exemplary embodiments, after the laser beam of the laser beam unit (101) is irradiated onto the sealing portion (SS1), the press operation of the sealing portion (SS1) by the press unit (102) may be performed at the same location.

[0081] The press unit (102) may include an upper press unit (102T) and a lower press unit (102B). The upper press unit (102T) may be positioned to face a lead pouch (LP). The lower press unit (102B) may be positioned to face a bottom pouch (BP). Each of the upper press unit (102T) and the lower press unit (102B) may overlap with the sealing portion (SS1) in the Z direction.

[0082] The press unit (102) can apply pressure to the sealant layers (BI, LI) bonded in the sealing section (SS1) to seal the sealant layers (BI, LI). Since the sealant layers (BI, LI) are uniformly melted by the laser beam unit (101), sealing in the press unit (102) is facilitated and the sealing quality can be improved.

[0083]

[0084] (2nd Example)

[0085] FIG. 5 is a flowchart illustrating a method for manufacturing a pouch-type secondary battery (PC) according to exemplary embodiments.

[0086]

[0087] Referring to FIGS. 1 to 5 together, in P10, the electrode assembly (EA) can be housed in the storage portion of the pouch (PP), and the bottom pouch (BP) and the lead pouch (LP) can be aligned. The bottom pouch (BP) and the lead pouch (LP) can be aligned so that their respective sealant layers (BI, LI) face each other.

[0088] In P20, a laser beam (LT, LB) can be irradiated onto the sealing portion (SS1) of the pouch (PP). The step (P20) of irradiating the laser beam (LT, LB) onto the sealing portion (SS1) can be performed by a laser beam unit (101). The laser beam (LT, LB) irradiated onto the sealing portion (SS1) can selectively heat only the metal layers (BM, LM) of the sealing portion (SS1). For example, if the metal layers (BM, LM) of the pouch (PP) are aluminum, the wavelength of the laser beam (LT, LB) irradiated onto the sealing portion (SS1) may be approximately 0.01 μm or more and approximately 0.1 μm or less, or approximately 0.8 μm or more and approximately 1.0 μm or less. In the above-described wavelength range, the laser beam absorption rate of the metal layers (BM, LM) is greater than the laser beam absorption rate of the protective layers (BO, LO). Therefore, the metal layers (BM, LM) can be selectively heated without the need to heat the protective layers (BO, LO) with low thermal conductivity. The heated metal layers (BM, LM) can melt the sealant layers (BI, LI).

[0089] The step (P20) of irradiating a laser beam (LT, LB) onto a sealing portion (SS1) may be performed until the temperature of the metal layer (BM) of the bottom pouch (BP) and the temperature of the metal layer (LM) of the lead pouch (LP) at the sealing portion (SS1) each reach a predetermined temperature. According to exemplary embodiments, the predetermined temperature may be above the melting temperature of the sealant layer (BI) of the bottom pouch (BP) and above the melting temperature of the sealant layer (LI) of the lead pouch (LP). According to exemplary embodiments, the predetermined temperature may be about 120°C or higher and about 190°C or lower. According to exemplary embodiments, the step (P20) of irradiating a laser beam (LT, LB) onto a sealing portion (SS1) may be performed for a time of about 0.5 seconds to about 1 second.

[0090] In P30, the sealing portion (SS1) of the pouch (PP) can be pressed. The step (P30) of pressing the sealing portion (SS1) can be performed by a press unit (102). The sealant layers (BI, LI) of the sealing portion (SS1) melted in P20 can be sealed in the press step of P30.

[0091] In P40, an electrolyte may be injected into the receiving space of the electrode assembly (EA) of the pouch (PP). The electrolyte may enable the movement of lithium ions. The electrolyte may comprise a lithium salt and an organic solvent. According to exemplary embodiments, the lithium salt may comprise any one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium perchlorate (LiClO4). According to exemplary embodiments, the organic solvent may comprise any one of ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), and diethyl carbonate (DEC).

[0092] In P50, the second sealing portion (SS2) of the pouch (PP) can be sealed. The sealing of the second sealing portion (SS2) may be performed using the laser sealing method described above in P30, or by a heat fusion method using a heater.

[0093]

[0094] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

Claims

1. A step of aligning a bottom pouch and a lead pouch, wherein each of the bottom pouch and the lead pouch comprises a sealant layer, a protective layer, and a metal layer between the sealant layer and the protective layer, and the sealant layer of the bottom pouch is aligned to face the sealant layer of the lead pouch; and The method includes the step of irradiating a laser beam onto the first sealing portion of the bottom pouch and the lid pouch. A method for manufacturing a secondary battery, characterized in that the wavelength of the laser beam is in the range of 0.01 μm to 0.1 μm or, in the range of 0.8 μm to 1.0 μm.

2. In Paragraph 1, The absorption rate of the laser beam by the metal layer of the bottom pouch is higher than the absorption rate of the laser beam by the protective layer of the bottom pouch, and A method for manufacturing a secondary battery, characterized in that the absorption rate of the laser beam by the metal layer of the lead pouch is higher than the absorption rate of the laser beam by the protective layer of the lead pouch.

3. In Paragraph 1, A method for manufacturing a secondary battery, characterized in that, in the step of irradiating a laser beam onto the first sealing portion, the sealant layer of the bottom pouch and the sealant layer of the lead pouch are each melted.

4. In Paragraph 1, A method for manufacturing a secondary battery, characterized in that, in the step of irradiating a laser beam onto the first sealing portion, the metal layer of the bottom pouch is heated above the melting temperature of the sealant layer of the bottom pouch, and the metal layer of the lead pouch is heated above the melting temperature of the sealant layer of the lead pouch.

5. In Paragraph 1, Each of the metal layer of the bottom pouch and the metal layer of the lead pouch comprises aluminum, and A method for manufacturing a secondary battery, characterized in that the sealant layer of the bottom pouch and the sealant layer of the lead pouch each comprise polypropylene.

6. In Paragraph 1, A method for manufacturing a secondary battery, characterized in that the step of irradiating a laser beam onto the first sealing portion is performed for a time of 0.5 seconds or more and 1 second or less.

7. In Paragraph 1, After the step of irradiating a laser beam onto the first sealing portion, A method for manufacturing a secondary battery, characterized by further including the step of applying pressure to the first sealing portion.

8. In Paragraph 7, After the step of applying pressure to the first sealing portion, A step of injecting an electrolyte into the receiving space of the electrode assembly between the bottom pouch and the lead pouch; and A method for manufacturing a secondary battery, further comprising the step of sealing a second sealing portion of the bottom pouch and the lead pouch.

9. In Paragraph 8, The first sealing portion overlaps with the electrode leads of the electrode assembly, and A method for manufacturing a secondary battery, characterized in that the second sealing portion does not overlap with the electrode leads of the electrode assembly.

10. In Paragraph 1, The melting temperature of the protective layer of the bottom pouch is higher than the melting temperature of the sealant layer of the bottom pouch, and A method for manufacturing a secondary battery, characterized in that the melting temperature of the protective layer of the lead pouch is higher than the melting temperature of the sealant layer of the lead pouch.

11. A laser beam unit configured to irradiate a laser beam onto a sealing portion in which a first metal layer, a first sealant layer, a second sealant layer, and a second metal layer are sequentially laminated; and A press unit configured to apply pressure to the sealing portion; and A secondary battery manufacturing apparatus characterized in that the wavelength of the laser beam is in the range of 0.01 μm to 0.1 μm or, in the range of 0.8 μm to 1.0 μm.

12. In Paragraph 11, A secondary battery manufacturing apparatus characterized in that the laser beam unit is configured to irradiate the sealing portion with a laser for a period of time of 0.5 seconds or more and 1 second or less.

13. In Paragraph 11, A secondary battery manufacturing apparatus characterized in that each of the first metal layer and the second metal layer comprises aluminum.

14. In Paragraph 11, The absorption rate of the laser beam of the first metal layer is greater than the absorption rate of the laser beam of the first sealant layer, and A secondary battery manufacturing apparatus characterized in that the absorption rate of the laser beam of the second metal layer is greater than the absorption rate of the laser beam of the second sealant layer.

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