Method for manufacturing exterior material for lithium secondary battery, method for manufacturing lithium secondary battery, device for manufacturing exterior material for lithium secondary battery, and lithium secondary battery

Abstract

A method for manufacturing an exterior material for a lithium secondary battery according to an embodiment of the present disclosure comprises the steps of: (a) preparing an electrode assembly mold and an exterior material; (b) the electrode assembly mold is wrapped with the exterior material, and a part of the exterior material is grabbed, and a part of the electrode assembly mold is grabbed; and (c) pulling a portion of the exterior material gripped in the step (b) so that the electrode assembly mold is adjacent to the exterior material.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an exterior material for a lithium secondary battery, a method for manufacturing a lithium secondary battery, an apparatus for manufacturing an exterior material for a lithium secondary battery, and a lithium secondary battery. Background Art

[0002] With the development of the electronics, communications, and aviation industries, the demand for lithium secondary batteries (lithium secondary batteries) as energy sources is increasing. In particular, with the emphasis on global environmental protection policies, the electric vehicle market is growing rapidly, and research and development of lithium secondary batteries is actively progressing both domestically and internationally.

[0003] Lithium secondary batteries can be categorized by their shape into cylindrical batteries, prismatic batteries, and pouch-type batteries. Pouch-type batteries can provide sufficient energy density and are therefore preferred over other battery types.

[0004] On the other hand, when manufacturing pouch-type batteries, a forming process can be performed on the pouch-type outer packaging material to give it a shape suitable for accommodating the electrode assembly. For example, with both ends of the pouch-type outer packaging material fixed, a forming punch is used to push the center area of ​​the pouch-type outer packaging material to form the pouch-type outer packaging material.

[0005] However, when the forming punch pushes the bag-shaped outer packaging material in one direction, at least a portion of the bag-shaped outer packaging material stretches in the pushing direction, potentially causing physical damage such as cracks in the stretched area. In this case, it may be difficult to re-evaluate the stability and reliability of the battery.

[0006] Therefore, it is necessary to study a process product and process method that can ensure the physical structural stability of the bag-type outer packaging material. Summary of the Invention

[0007] (1) Technical issues to be resolved

[0008] The embodiments of the present disclosure aim to provide a method for manufacturing an outer packaging material for a lithium secondary battery, a method for manufacturing a lithium secondary battery, an apparatus for manufacturing an outer packaging material for a lithium secondary battery, and a lithium secondary battery, which can apply a sufficient number of electrode units to ensure energy density while preventing physical defects of the outer packaging material, thereby improving the stability of the battery.

[0009] (2) Technical solution

[0010] According to an embodiment of the present disclosure, a method for manufacturing a lithium secondary battery may include the following steps: (a) preparing an electrode assembly mold and an outer packaging material; (b) wrapping the electrode assembly mold with the outer packaging material and grabbing a portion of the outer packaging material; and (c) pulling the portion of the outer packaging material grabbed in step (b) so that the electrode assembly mold is adjacent to the outer packaging material.

[0011] According to an embodiment, the shape of the electrode assembly mold may correspond to the shape of the electrode assembly to be accommodated in the exterior material.

[0012] According to an embodiment, the thickness of the electrode assembly mold may correspond to the thickness of the electrode assembly to be accommodated in the exterior material.

[0013] According to an embodiment, the step (b) may include the following steps: exposing both end portions of the electrode assembly mold with the exterior material; and surrounding an outer side surface of the electrode assembly mold with the exterior material.

[0014] According to an embodiment, the step (c) may include bringing the exterior material into contact with the electrode assembly mold so that a region surrounded by the exterior material has the same shape as that of the electrode assembly mold.

[0015] According to an embodiment, the step (c) may include the step of deforming the shape of the exterior material without pressing one side of the exterior material.

[0016] According to an embodiment, the method may further include the step of forming each edge of the electrode assembly mold adjacent to the exterior material in the step (c).

[0017] According to an embodiment, the manufacturing method may further include the step of molding a portion of the exterior material between a pulling device that pulls a portion of the exterior material and the electrode assembly mold.

[0018] According to an embodiment of the present disclosure, a method for manufacturing a lithium secondary battery may include the following steps: (a) preparing an electrode assembly mold and an outer packaging material; (b) wrapping the electrode assembly mold with the outer packaging material and grabbing a portion of the outer packaging material; (c) pulling the portion of the outer packaging material grabbed in step (b) so that the electrode assembly mold is adjacent to the outer packaging material; (d) shaping each edge of the outer packaging material adjacent to the electrode assembly mold in step (c); and (e) after performing step (d), removing the electrode assembly mold and accommodating the electrode assembly in the outer packaging material.

[0019] According to an embodiment, the thickness of the electrode assembly mold may be substantially the same as the thickness of the electrode assembly to be accommodated in the exterior material. The shape of the electrode assembly mold may be substantially the same as the shape of the electrode assembly to be accommodated in the exterior material.

[0020] According to an embodiment, the step (b) may include the following steps: exposing both end portions of the electrode assembly mold with the exterior material; and surrounding an outer side surface of the electrode assembly mold with the exterior material.

[0021] According to an embodiment, the step (c) may include the step of deforming the shape of the exterior material without pressing one side of the exterior material.

[0022] According to an embodiment of the present disclosure, a manufacturing device for an outer packaging material for a lithium secondary battery may include: an electrode assembly mold having the same shape as the electrode assembly; and a pulling device, which is arranged on one side of the electrode assembly mold, grabs the end of the bag-type outer packaging material for accommodating the electrode assembly, and pulls the end of the bag-type outer packaging material.

[0023] According to an embodiment, the manufacturing apparatus may further include: a molding portion configured to press at least a portion of the bag-type exterior packaging material.

[0024] According to an embodiment, the thickness of the electrode assembly mold may be substantially the same as the thickness of the electrode assembly. The shape of the electrode assembly mold may be substantially the same as the shape of the electrode assembly.

[0025] According to an embodiment of the present disclosure, a lithium secondary battery may include: an outer packaging material; and an electrode assembly housed within the outer packaging material and including an electrode unit, wherein the electrode unit includes a positive electrode, a negative electrode, and a separator. The outer packaging material may include a top surface, a bottom surface, and side surfaces. The thickness of the outer packaging material at the side surfaces may be greater than or equal to 0.8 times and less than or equal to 1.0 times the thickness of the outer packaging material at the top surface.

[0026] According to an embodiment, the lithium secondary battery may further include: a positive electrode tab electrically connected to the positive electrode; and a negative electrode tab electrically connected to the negative electrode. The exterior packaging material may include a bag seal. The bag seal may include: a side seal disposed adjacent to the positive electrode tab or the negative electrode tab; and a main body seal disposed between the side seals. The side surfaces may include a first side surface adjacent to the main body seal and a second side surface adjacent to the side seals.

[0027] According to an embodiment, a thickness of the exterior material at the side surface may be 0.9 times or more and 1.0 times or less of a thickness of the exterior material at the top surface.

[0028] (3) Beneficial effects

[0029] According to the embodiments of the present disclosure, a method for manufacturing an outer packaging material for a lithium secondary battery, a method for manufacturing a lithium secondary battery, an apparatus for manufacturing an outer packaging material for a lithium secondary battery, and a lithium secondary battery can be provided, which can apply a sufficient number of electrode units to ensure energy density while preventing physical defects of the outer packaging material, thereby improving the stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic perspective view showing a lithium secondary battery according to an embodiment.

[0031] Figure 2 is a schematic expanded plan view showing a lithium secondary battery according to an embodiment.

[0032] Figure 3 and Figure 4 is a schematic cross-sectional view showing a lithium secondary battery according to an embodiment.

[0033] Figures 5 to 17 is a schematic diagram illustrating a method of manufacturing a lithium secondary battery according to an embodiment. DETAILED DESCRIPTION

[0034] The structural or functional descriptions of the embodiments of the concepts of the present disclosure disclosed in this specification or application are merely shown for the purpose of illustrating the embodiments of the concepts of the present disclosure. The embodiments of the concepts of the present disclosure may be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application.

[0035] Hereinafter, a method for manufacturing a lithium secondary battery exterior material, a method for manufacturing a lithium secondary battery, and an apparatus for manufacturing a lithium secondary battery exterior material according to embodiments will be described with reference to the accompanying drawings.

[0036] First, refer to Figures 1 to 4 , a lithium secondary battery 1 according to an embodiment will be described.

[0037] Figure 1 is a schematic perspective view showing a lithium secondary battery according to an embodiment. Figure 2 is a schematic expanded plan view showing a lithium secondary battery according to an embodiment. Figure 3 and Figure 4 is a schematic cross-sectional view showing a lithium secondary battery according to an embodiment.

[0038] Reference Figures 1 to 4The lithium secondary battery 1 may be a pouch-type secondary battery. The lithium secondary battery 1 includes a lithium secondary battery outer packaging material 10 and an electrode assembly 5 housed within the lithium secondary battery outer packaging material 10. According to an embodiment, the lithium secondary battery 1 may further include a positive electrode tab 120 and a negative electrode tab 140.

[0039] Hereinafter, the exterior packaging material 10 for a lithium secondary battery will be referred to as an "exterior packaging material" for convenience of description.

[0040] The outer packaging material 10 may include various substances. For example, the outer packaging material 10 may be a bag film including an aluminum layer and a polypropylene layer. However, the present disclosure is not necessarily limited to specific examples.

[0041] The exterior material 10 may include a bag film 11 and a bag sealing portion 12 formed at the periphery of the bag film 11. The bag film 11 may include a first bag film 11a and a second bag film 11b formed integrally with each other.

[0042] The first bag film 11a and the second bag film 11b may be divided based on a dividing line 16. The first bag film 11a and the second bag film 11b may be joined at one end of the outer packaging material to form a bag sealing portion 12 that separates a space 14 from the outside.

[0043] The first bagging film 11a and the second bagging film 11b may face each other and form a space 14 for accommodating the electrode assembly 5. The space 14 may also be referred to as a molding portion.

[0044] Depending on the embodiment, the space 14 can be formed when a portion of the first bagging film 11a is recessed. Alternatively, depending on the embodiment, the space 14 can be formed when a portion of the second bagging film 11b is recessed. Alternatively, depending on the embodiment, the space 14 can be formed when at least a portion of each of the first bagging film 11a and the second bagging film 11b is recessed. For ease of explanation, the following description will be based on an embodiment in which the space 14 is formed in the first bagging film 11a.

[0045] The size of the space 14 may correspond to the size of the electrode assembly 5. For example, the height of the space 14 may be substantially the same as the thickness of the electrode assembly 5. That is, the size of the space 14 may be determined according to the size of the electrode assembly 5.

[0046] According to the embodiment, the physical stability of the outer packaging material 10 during the manufacturing process can be ensured, so the outer packaging material 10 can be manufactured to have a sufficient height of the space 14. In other words, the thickness of the electrode assembly 5 can be freely selected based on the user's intention and the desired energy density of the lithium secondary battery 1. The details related to this will be described later.

[0047] According to an embodiment, the bag seal portion 12 may include a main seal portion 12a adjacent to the area between the positive electrode tab 120 and the negative electrode tab 140, and a side seal portion 12b adjacent to the positive electrode tab 120 and the negative electrode tab 140. The main seal portion 12a may be disposed between the side seal portion 12b corresponding to the positive electrode tab 120 and the side seal portion 12b corresponding to the negative electrode tab 140.

[0048] According to an embodiment, the outer packaging material 10 can be manufactured to include a space 14 for accommodating the electrode assembly 5. When performing the process of forming the space 14 in the outer packaging material 10, the bag film used to manufacture the outer packaging material 10 can be made without excessive stretching. Therefore, the thickness of the outer packaging material 10 according to an embodiment can be substantially uniform. According to an embodiment, the thickness at one location of the outer packaging material 10 can be substantially the same as the thickness at another location of the outer packaging material 10. Therefore, the insulation performance and resistance deviation of the outer packaging material 10 according to an embodiment can be substantially uniform at different locations.

[0049] According to an embodiment, the outer packaging material 10 may include a top surface US, a bottom surface LS, and side surfaces SS. For example, the first bagging film 11a may include a top surface US and side surfaces SS, and the second bagging film 11b may include a bottom surface LS. Side surfaces SS may include a first side surface adjacent to the body seal portion 12a and a second side surface adjacent to the side seal portion 12b.

[0050] According to an embodiment, the side surface SS may refer to the outer surface of the exterior material 10 along the thickness direction of the electrode assembly 5 (or the height direction of the lithium secondary battery 1). The top surface US and the bottom surface LS may refer to the outer surface of the exterior material 10 along the area direction of the electrode assembly 5 (or the lithium secondary battery 1).

[0051] According to an embodiment, the difference among the thickness of the exterior material 10 at the top surface US, the thickness of the exterior material 10 at the bottom surface LS, and the thickness of the exterior material 10 at the side surface SS may be less than or equal to a preset difference (or may correspond to each other).

[0052] For example, the thickness of the exterior material 10 at the side surface SS may be 0.8 times or more and 1.0 times or less of the thickness of the exterior material 10 at the top surface US. The thickness of the exterior material 10 at the side surface SS may be 0.8 times or more and 1.0 times or less of the thickness of the exterior material 10 at the bottom surface LS. In another example, the thickness of the exterior material 10 at the side surface SS may be 0.9 times or more and 1.0 times or less of the thickness of the exterior material 10 at the top surface US. The thickness of the exterior material 10 at the side surface SS may be 0.9 times or more and 1.0 times or less of the thickness of the exterior material 10 at the bottom surface LS.

[0053] Experimentally, when the bag film is overstretched to form the space 14, the thickness of the bag film may become excessively thin at the position corresponding to the side surface SS. For example, in the prior art, when the bag film is stretched, the thickness of the thinned bag film may be manufactured to be less than 0.5 times the thickness of the original bag film. In this case, the durability of the lithium secondary battery 1 may be impaired, and the bag film may not have sufficient insulation properties. However, the exterior material 10 according to the embodiment can be manufactured without being overstretched, and thus can have the above-mentioned structural features, thereby avoiding the above-mentioned risks. The manufacturing method of the exterior material 10 related to this will be described later.

[0054] The electrode assembly 5 includes one or more electrode cells. Each electrode cell includes a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. The electrode assembly 5 may be provided with an electrolyte. The electrode assembly 5 may be manufactured by winding, laminating, or folding the electrode cells. Depending on the embodiment, the electrode assembly 5 may have a jelly-roll structure. However, the shape of the electrode assembly 5 is not particularly limited.

[0055] Each of the positive electrode and the negative electrode may include a current collector forming a plate and an active material layer disposed on the current collector. For example, the positive electrode may include a positive current collector and a positive active material layer on the positive current collector, and the negative electrode may include a negative current collector and a negative active material layer on the negative current collector.

[0056] The current collector may include a known conductive material within the range that does not cause a chemical reaction in the lithium secondary battery 1. For example, the current collector may include one or more of stainless steel, nickel (Ni), aluminum (Al), titanium (Ti), copper (Cu), and alloys thereof, and may be provided in various forms such as a film, sheet, or foil.

[0057] The active material layer contains an active material. For example, the positive electrode active material layer may contain a positive electrode active material, and the negative electrode active material layer may contain a negative electrode active material.

[0058] The positive electrode active material may be a material capable of intercalating and deintercalating lithium (Li) ions. The positive electrode active material may be a lithium metal oxide. For example, the positive electrode active material may be one of a lithium manganese-based oxide, a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium nickel manganese-based oxide, a lithium nickel cobalt manganese-based oxide, a lithium nickel cobalt aluminum-based oxide, a lithium iron phosphate-based compound, a lithium manganese phosphate-based compound, a lithium cobalt phosphate-based compound, or a lithium vanadium phosphate-based compound. However, the present disclosure is not necessarily limited to the above examples.

[0059] The negative electrode active material can be a substance that can absorb and deintercalate lithium ions. For example, the negative electrode active material can be a carbon-based material such as crystalline carbon, amorphous carbon, carbon composites, or carbon fibers, or any of lithium alloys, silicon (Si), and tin (Sn). In some embodiments, the negative electrode active material can be natural graphite or artificial graphite, but is not limited to these specific examples.

[0060] Each of the positive electrode and the negative electrode may further include a binder and a conductive material.

[0061] The binder can improve mechanical stability by mediating the bonding between the current collector and the active material layer. According to an embodiment, the binder can be an organic binder or a water-based binder, and can also be used together with a thickener such as carboxymethyl cellulose (CMC). According to an embodiment, the organic binder can be any one of vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, and polymethylmethacrylate (polymethylmethancrylate), and the water-based binder can be styrene-butadiene rubber (SBR), but the present disclosure is not necessarily limited thereto.

[0062] The conductive material can improve the conductivity of the lithium secondary battery 1. The conductive material can include a metal-based substance. According to an embodiment, the conductive material can include a common carbon-based conductive material. For example, the conductive material can include any one of graphite, carbon black, graphene, and carbon nanotubes. Preferably, the conductive material can include carbon nanotubes.

[0063] The separator may be provided between the positive electrode and the negative electrode. The separator is configured to prevent an electrical short circuit between the positive electrode and the negative electrode and to facilitate the flow of ions.

[0064] The separator may include a porous polymer membrane or a porous non-woven fabric. The porous polymer membrane may be constructed as a single layer or multiple layers containing polyolefin-based polymers such as ethylene polymer, propylene polymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer. The porous non-woven fabric may include high-melting-point glass fiber or polyethylene terephthalate fiber. However, this is not limiting. In some embodiments, the separator may be a highly heat-resistant ceramic separator (CCS).

[0065] On the other hand, the positive electrode can be electrically connected to the positive electrode tab 120, and can be electrically connected to the positive electrode lead of the conductive material through the positive electrode tab 120. According to an embodiment, the negative electrode can be electrically connected to the negative electrode tab 140, and can be electrically connected to the negative electrode lead of the conductive material through the negative electrode tab 140. The positive electrode lead and the negative electrode lead electrically connected to the positive electrode tab 120 and the negative electrode tab 140 can serve as electrode interfaces that electrically connect the lithium secondary battery 1 to an external device.

[0066] Below, refer to Figures 5 to 17 , a method for manufacturing a lithium secondary battery exterior material, a method for manufacturing a lithium secondary battery, and an apparatus for manufacturing a lithium secondary battery exterior material according to an embodiment are described.

[0067] Figures 5 to 17 is a schematic diagram illustrating a method of manufacturing a lithium secondary battery according to an embodiment.

[0068] Figures 5 to 8 、 Figures 10 to 12 This is a partial step of the method for manufacturing a lithium secondary battery according to the embodiment, and may be a diagram illustrating a method for manufacturing the lithium secondary battery exterior material 10 . Figures 5 to 8 、 Figures 10 to 13 A process for manufacturing the lithium secondary battery exterior material 10 using an apparatus for manufacturing the lithium secondary battery exterior material 10 is shown.

[0069] Figure 9 、 Figures 14 to 16 The process steps for housing the electrode assembly 5 in the lithium secondary battery exterior material 10 are shown. Figure 17 The process steps for forming the bag sealing portion 12 in the lithium secondary battery exterior material 10 are shown.

[0070] According to the embodiment, a manufacturing apparatus for a lithium secondary battery exterior material is used to manufacture the lithium secondary battery exterior material 10. Hereinafter, the manufacturing apparatus for a lithium secondary battery exterior material is referred to as "exterior material manufacturing apparatus" for convenience of description.

[0071] The manufacturing apparatus of the exterior material includes an electrode assembly mold 1200 and a pulling device 2200. The pulling device 2200 is provided on one side of the electrode assembly mold 1200 and can deform the shape of the exterior material 10.

[0072] The manufacturing apparatus of the exterior material may further include a molding unit, wherein the molding unit includes a first molding unit 2400 and a second molding unit 2600 .

[0073] The electrode assembly mold 1200 may be a component for forming the space 14 in the exterior material 10 corresponding to the shape of the electrode assembly 5 .

[0074] For example, the electrode assembly mold 1200 may have a shape corresponding to the shape of the electrode assembly 5 to be accommodated in the exterior material 10. The electrode assembly mold 1200 may have a volume corresponding to the volume of the electrode assembly 5 to be accommodated in the exterior material 10. The electrode assembly mold 1200 may have a thickness substantially the same as the thickness of the electrode assembly 5 to be accommodated in the exterior material 10.

[0075] According to an embodiment, the electrode assembly mold 1200 may have a hexahedral shape similar to the electrode assembly 5 , but the present disclosure is not limited to a specific example.

[0076] The pulling device 2200 may grasp a portion of the exterior material 10 (eg, an end portion of the exterior material 10 ). For example, the pulling device 2200 may be configured to pressurize a portion of the exterior material 10 and fix the portion of the exterior material 10 .

[0077] The pulling device 2200 can pull a portion of the gripped outer packaging material 10. For example, after gripping a portion of the outer packaging material 10, the pulling device 2200 can pull the outer packaging material 10 from the electrode assembly mold 1200 toward the pulling device 2200. Depending on the embodiment, the position of at least a portion of the pulling device 2200 can be changed, but the operation of the pulling device 2200 is not limited to a specific example.

[0078] The first molding part 2400 and the second molding part 2600 may be provided in plurality to press a portion of the exterior material 10. The first molding part 2400 may be a member for pressing a portion of the exterior material 10 adjacent to the region housing the electrode assembly 5. The second molding part 2600 may be a member for pressing an edge region of the portion of the exterior material 10 housing the electrode assembly 5.

[0079] Hereinafter, each step of a method for manufacturing the exterior packaging material 10 and a method for manufacturing the lithium secondary battery 1 including the same will be described.

[0080] Reference Figure 5 and Figure 10 , the electrode assembly mold 1200, the exterior material 10, and the pulling device 2200 may be prepared. In addition, the exterior material 10 may wrap the electrode assembly mold 1200. In addition, the end of the exterior material 10 may be grasped by the pulling device 2200.

[0081] In this step, the exterior material 10 can expose both ends of the electrode assembly mold 1200 and can surround the outer side of the electrode assembly mold 1200. Therefore, the exterior material 10 can surround the space where the electrode assembly mold 1200 is set. According to an embodiment, the exposed ends of the electrode assembly mold 1200 can correspond to the positions of the positive electrode tab 120 and the negative electrode tab 140 of the lithium secondary battery 1 manufactured later.

[0082] According to an embodiment, the exterior material 10 may expose both ends of the electrode assembly mold 1200 and extend further from both ends toward the periphery. For example, the distance between the two ends of the electrode assembly mold 1200 may be less than the length of the exterior material 10 in the same direction. Therefore, when subsequent processes are performed, a space 14 corresponding to the electrode assembly mold 1200 may be appropriately formed in a portion of the exterior material 10.

[0083] In this step, the pulling device 2200 can grab one end of the exterior material 10 , so that the exterior material 10 can be set to surround the electrode assembly mold 1200 .

[0084] Reference Figure 6 and Figure 11 , the pulling device 2200 can pull the end of the grasped exterior material 10 , and thus the exterior material 10 surrounding the electrode assembly mold 1200 can be adjacent to the electrode assembly mold 1200 .

[0085] In this step, the pulling device 2200 may pull the end portion of the exterior material 10 in a pulling direction D away from the electrode assembly mold 1200 .

[0086] In this step, the outer packaging material 10 wrapping the electrode assembly mold 1200 may have a shape corresponding to the shape of the electrode assembly mold 1200. For example, the outer packaging material 10 may be directly adjacent to the electrode assembly mold 1200 and may be in contact with the electrode assembly mold 1200. Therefore, the shape of the outer packaging material 10 may be deformed to have a shape substantially the same as the outer side surface of the electrode assembly mold 1200.

[0087] According to embodiments, the outer packaging material 10 may be formed without pressing one side of the outer packaging material 10 with a forming punch. Experimentally, when the outer packaging material 10 is pressed against one side (e.g., the center area) of the outer packaging material 10 to form the outer packaging material 10, the portion of the outer packaging material 10 in the direction of the forming punch's pressing is stretched, potentially causing physical damage to at least a portion of the outer packaging material 10. This can ultimately make it difficult to ensure battery stability. For example, in conventional methods, the side portions of the outer packaging material 10 are stretched, causing its thickness to be excessively reduced, which can compromise battery stability. Furthermore, conventional methods make it difficult to achieve uneven thickness in the outer packaging material 10 at different locations, making it difficult to re-evaluate the reliability of the outer packaging material 10's insulation and protective properties. Furthermore, this can lead to process limitations that make it difficult to sufficiently press the outer packaging material 10, which means that it is difficult to expand the space for accommodating the electrode assembly 5 beyond a certain level. Ultimately, using conventional outer packaging material 10 forming processes, it is difficult to accommodate a sufficient number of electrode assemblies 5, making it difficult to achieve sufficient battery energy density.

[0088] However, the manufacturing method according to the embodiment minimizes the stretching of the exterior material 10. To form the space 14 in the exterior material 10 according to the embodiment, a process can be employed that pulls a portion of the exterior material 10. In this case, the risk of excessive pressure on one side of the exterior material 10 can be substantially eliminated. In other words, according to the embodiment, the stability of the battery can be ensured, ultimately enabling the lithium secondary battery 1 to be manufactured with a high energy density.

[0089] Reference Figure 7 and Figure 12 The first molding part 2400 can mold the exterior material 10 between the electrode assembly mold 1200 and the pulling device 2200 .

[0090] According to an embodiment, a plurality of first molding parts 2400 are provided, each of which can press one side and the other side of the exterior material 10 between the electrode assembly mold 1200 and the pulling device 2200. The first molding parts 2400 can have a rigidity suitable for pressing the exterior material 10, and the shape and physical properties of the first molding parts 2400 are not particularly limited.

[0091] In this step, the first molding part 2400 may push the area directly adjacent to the electrode assembly mold 1200 , and thus, the surface adjacent to the pulling device 2200 of the electrode assembly mold 1200 may be adjacent to and surround the electrode assembly mold 1200 .

[0092] In this step, the first molding part 2400 can simultaneously press one side and the other side of the exterior packaging material 10 , and no process risk caused by the pressing of the exterior packaging material 10 is generated.

[0093] Reference Figure 8 and Figure 13 The second molding part 2600 may mold the edges of the exterior packaging material 10 adjacent to the electrode assembly mold 1200 .

[0094] According to an embodiment, a plurality of second molding parts 2600 are provided to press the outer packaging material 10 adjacent to the electrode assembly mold 1200 to form an edge region. The second molding parts 2600 can have a rigidity suitable for pressing the outer packaging material 10, and the shape and physical properties of the second molding parts 2600 are not particularly limited.

[0095] In this step, the second molding unit 2600 can press the edge regions of the exterior packaging material 10, so that the space 14 surrounded by the exterior packaging material 10 can be defined to further correspond to the shape of the electrode assembly mold 1200. According to an embodiment, the second molding unit 2600 can press all four edge regions of the exterior packaging material 10.

[0096] In this step, the second molding unit 2600 can push a portion of the exterior packaging material 10 while the electrode assembly mold 1200 supports the lower portion, and no process risk caused by pushing the exterior packaging material 10 is generated.

[0097] On the other hand, the relationship between the steps of molding the exterior material 10 by the first molding unit 2400 and the steps of molding the exterior material 10 by the second molding unit 2600 is not particularly limited. For example, the step of molding the exterior material 10 by the first molding unit 2400 may be performed earlier than the step of molding the exterior material 10 by the second molding unit 2600. Depending on the embodiment, the step of molding the exterior material 10 by the second molding unit 2600 may also be performed earlier than the step of molding the exterior material 10 by the first molding unit 2400.

[0098] Reference Figure 9 、 Figures 14 to 16 , the formed outer packaging material 10 can be removed to form the inner electrode assembly mold 1200 and accommodate the electrode assembly 5.

[0099] In this step, by removing the electrode assembly mold 1200 , a space 14 having substantially the same size as the electrode assembly mold 1200 may be formed.

[0100] Before performing this step, the electrode assembly 5 including the positive electrode, negative electrode, and separator can be manufactured. For example, a jelly-roll type electrode assembly 5 can be prepared. Alternatively, the electrode assembly 5 can be housed within the exterior material 10 and provided within the space 14. As described above, the space 14 is defined based on the electrode assembly mold 1200 having substantially the same dimensions as the electrode assembly 5, and the exterior material 10 can enclose the space 14 to a size (e.g., thickness) appropriate for the electrode assembly 5.

[0101] Reference Figure 17 The outer packaging material 10 may be formed with a bag seal portion 12. For example, a positive electrode tab 120 and a negative electrode tab 140 connected to the electrode assembly 5 may be provided, and the first bag film 11a and the second bag film 11b may be heat-welded along a sealing region 12' to form the bag seal portion 12. According to an embodiment, an electrolyte may be injected into the outer packaging material 10 before forming the bag seal portion 12. The sealing region 12' for forming the bag seal portion 12 may be formed along the edge regions of the first bag film 11a and the second bag film 11b.

[0102] According to an embodiment, the first bagging film 11a and the second bagging film 11b may each include a polyolefin resin (e.g., a polypropylene resin) capable of functioning as a sealant. When the first bagging film 11a and the second bagging film 11b are brought into contact with each other and then heat-pressed, the polyolefin resin may melt to seal the outer packaging material 10.

[0103] According to embodiments, as the thickness of the electrode assembly 5 increases, or as the areas of the first and second pouch films 11a and 11b along the sealing region 12' are slightly larger, the sealing region 12' can be appropriately modified to create a suitable pouch seal 12. For example, if the outer perimeter of the first pouch film 11a is slightly longer, the sealing region 12' can be defined to be slightly closer to the edge (e.g., the end) of the outer packaging material 10. As another example, as the thickness of the electrode assembly 5 increases, the sealing region 12' can be defined to be slightly closer to the edge (e.g., the end) of the outer packaging material 10. As a result, the pouch seal 12 can appropriately seal the area within the outer packaging material 10.

Claims

1. A method for manufacturing an outer packaging material for a lithium secondary battery, comprising the following steps: (a) Preparing electrode assembly molds and packaging materials; (b) wrapping the electrode assembly mold with the outer packaging material and grabbing a portion of the outer packaging material; as well as (c) pulling a portion of the outer packaging material grasped in step (b) so that the electrode assembly mold is adjacent to the outer packaging material.

2. The method for producing a lithium secondary battery exterior material according to claim 1, wherein: The shape of the electrode assembly mold corresponds to the shape of the electrode assembly to be accommodated in the exterior material.

3. The method for producing a lithium secondary battery exterior material according to claim 1, wherein: The thickness of the electrode assembly mold corresponds to the thickness of the electrode assembly to be accommodated in the exterior material.

4. The method for producing a lithium secondary battery exterior material according to claim 1, wherein: The step (b) comprises the following steps: exposing both ends of the electrode assembly mold to the exterior material; and The outer surface of the electrode assembly mold is surrounded by the outer packaging material.

5. The method for producing a lithium secondary battery exterior material according to claim 1, wherein: The step (c) comprises the following steps: The exterior material is brought into contact with the electrode assembly mold so that a region surrounded by the exterior material has the same shape as that of the electrode assembly mold.

6. The method for producing a lithium secondary battery exterior material according to claim 1, wherein: The step (c) comprises the following steps: The shape of the exterior material is deformed without pressing one side of the exterior material.

7. The method for producing an exterior packaging material for a lithium secondary battery according to claim 1, further comprising the following steps: Each edge of the electrode assembly mold adjacent to the exterior material in step (c) is molded.

8. The method for producing an exterior packaging material for a lithium secondary battery according to claim 1, further comprising the following steps: A portion of the exterior material is molded between a pulling device that pulls a portion of the exterior material and the electrode assembly mold.

9. A method for manufacturing a lithium secondary battery, comprising the following steps: (a) Preparing electrode assembly molds and packaging materials; (b) wrapping the electrode assembly mold with the outer packaging material and grabbing a portion of the outer packaging material; (c) pulling a portion of the outer packaging material grasped in step (b) so that the electrode assembly mold is adjacent to the outer packaging material; (d) shaping each edge of the outer packaging material adjacent to the electrode assembly mold in step (c); and (e) After performing step (d), removing the electrode assembly mold and housing the electrode assembly in the exterior material.

10. The method for manufacturing a lithium secondary battery according to claim 9, wherein: The thickness of the electrode assembly mold is substantially the same as the thickness of the electrode assembly contained in the outer packaging material. The shape of the electrode assembly mold is substantially the same as the shape of the electrode assembly to be accommodated in the exterior material.

11. The method for manufacturing a lithium secondary battery according to claim 9, wherein: The step (b) comprises the following steps: exposing both ends of the electrode assembly mold to the exterior material; and The outer surface of the electrode assembly mold is surrounded by the outer packaging material.

12. The method for manufacturing a lithium secondary battery according to claim 9, wherein: The step (c) comprises the following steps: The shape of the exterior material is deformed without pressing one side of the exterior material.

13. A device for manufacturing an outer packaging material for a lithium secondary battery, comprising: an electrode assembly mold having the same shape as the electrode assembly; as well as The pulling device is provided on one side of the electrode assembly mold, grabs an end portion of a bag-type outer packaging material for accommodating the electrode assembly, and pulls the end portion of the bag-type outer packaging material.

14. The manufacturing apparatus for a lithium secondary battery exterior material according to claim 13, further comprising: The molding portion is used to press at least a portion of the bag-shaped exterior material.

15. The manufacturing apparatus for a lithium secondary battery exterior material according to claim 13, wherein: The thickness of the electrode assembly mold is substantially the same as the thickness of the electrode assembly, The shape of the electrode assembly mold is substantially the same as that of the electrode assembly.

16. A lithium secondary battery comprising: exterior materials; as well as an electrode assembly housed in the outer packaging material and comprising an electrode unit, wherein the electrode unit comprises a positive electrode, a negative electrode, and a separator; The exterior material includes a top surface, a bottom surface and side surfaces, The thickness of the exterior material at the side surface is 0.8 times or more and 1.0 times or less of the thickness of the exterior material at the top surface.

17. The lithium secondary battery according to claim 16, further comprising: A positive electrode tab, electrically connected to the positive electrode; as well as A negative electrode tab, electrically connected to the negative electrode, The outer packaging material includes a bag sealing portion, The bag sealing portion comprises: a side sealing portion, disposed adjacent to the positive electrode tab or the negative electrode tab; as well as a main body sealing portion, disposed between the side sealing portions, The side surfaces include a first side surface adjacent to the body seal portion and a second side surface adjacent to the side seal portion.

18. The lithium secondary battery according to claim 16, wherein The thickness of the exterior material at the side surface is 0.9 times or more and 1.0 times or less of the thickness of the exterior material at the top surface.

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