Bag forming device and method

Abstract

The invention discloses a bag forming device and method. A bag forming method according to one embodiment of the present disclosure may comprise: an arrangement step of arranging a bag sheet between a die part comprising a forming lower surface on which the bag sheet is formed and a forming support part arranged on the forming lower surface, and a press part for forming the bag sheet; a primary molding step in which the inner space of the die part is vacuumized and the molding support part is lowered in the direction of the molding lower surface to bend the bag sheet; and a secondary molding step of lowering the press part in the direction of the molding lower surface to apply pressure to the bag sheet. The bag manufactured by the bag forming apparatus and method of the present disclosure can prevent the occurrence of cracks at the corners of the bag.

Description

Technical Field

[0001] The present disclosure relates to a bag forming device and method. Background Art

[0002] Conventional secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and widely used in electronic devices such as mobile phones, laptops, and camcorders, as well as electric vehicles. Lithium secondary batteries, in particular, have an operating voltage of approximately 3.6V and a capacity roughly three times that of nickel-cadmium and nickel-metal hydride batteries, which are commonly used as power sources for electronic devices. Their high energy density per unit weight has led to explosive growth in their use.

[0003] Secondary batteries are classified into coin-shaped, cylindrical, prismatic, and pouch-shaped batteries based on the shape of their housings. The electrode assembly, housed within the housing, is a rechargeable, power-generating element comprised of a stack of electrodes and separators.

[0004] Electrode assemblies can be broadly classified into a jelly-roll type in which a separator is placed between sheet-shaped positive and negative electrodes coated with active materials and wound together; a stacked type in which multiple positive and negative electrodes are stacked in sequence with separators placed between them; and a stacked / folded type in which stacked cells are wound around a long separator membrane.

[0005] Recently, pouch-type batteries with a structure in which a stacked or stacked / folded electrode assembly is built into a pouch-type battery case of aluminum laminate sheet have attracted widespread attention due to their low manufacturing cost, light weight, and easy shape deformation, and their use has gradually increased. Summary of the Invention

[0006] Technical issues

[0007] An implementation example of the present disclosure can provide a bag forming device and method, which can prevent cracks from occurring at the corners of the bag.

[0008] An implementation example of the present disclosure can provide a bag forming device and method, which can prevent bag expansion.

[0009] Another implementation example of the present disclosure may provide a pouch-type secondary battery manufactured according to the pouch molding method.

[0010] Technical Solution

[0011] As an implementation example of the present disclosure, a bag forming method includes: a configuration step of configuring a bag sheet between a die portion and a punching portion, wherein the die portion includes a forming lower surface for forming the bag sheet and a forming support portion configured on the forming lower surface, and the punching portion is used to form the bag sheet; a primary forming step of vacuuming the internal space of the die portion to cause the forming support portion to descend toward the forming lower surface to bend the bag sheet; and a secondary forming step of descending the punching portion toward the forming lower surface to apply pressure to the bag sheet.

[0012] The primary molding step and the secondary molding step may be performed simultaneously.

[0013] The secondary molding step may be performed after performing the primary molding step.

[0014] At least one of the forming support portion and the punching portion may descend at a constant speed.

[0015] The stamping portion may descend faster than the forming support portion.

[0016] The punching part may be lowered after the lowering of the forming support part is completed.

[0017] The punching part may be lowered while the forming support part is raised again after being lowered.

[0018] The interval between the forming support portion and the punching portion may be maintained below 1 mm.

[0019] The bag forming method according to an implementation example of the present disclosure may further include a speed adjustment step of controlling the moving speed of at least one of the forming support portion and the punching portion by a control portion.

[0020] The bag sheet bent in the primary forming step may be bent to protrude downward.

[0021] In the secondary molding step, a receiving portion for receiving the electrode assembly may be formed on the pouch sheet according to the shape of the punched portion.

[0022] A lithium secondary battery as another implementation example of the present disclosure includes a pouch manufactured by the above-described pouch molding method.

[0023] As another implementation example of the present disclosure, a bag forming device includes: a die portion, which is provided with a forming groove; a stamping portion, which is arranged to face the forming groove and is configured to move relative to the forming groove; a forming support portion, which is configured to move relative to the stamping portion inside the forming groove; and a control portion, which adjusts the moving speed of at least one of the forming support portion and the stamping portion.

[0024] The die portion further includes an inner space formed by the forming groove and the forming support portion, and may further include a vacuum device for forming a vacuum pressure in the inner space.

[0025] According to another embodiment of the present disclosure, the bag forming device may further include: a stripper, spaced apart and arranged on the fixing portion, for fixing the bag sheet.

[0026] Effects of the Invention

[0027] The bag formed by the bag forming device and method according to an embodiment of the present disclosure can prevent cracks from occurring at the corners of the bag.

[0028] A bag manufactured by a bag forming device and method according to an embodiment of the present disclosure can suppress expansion of the main cavity of the bag. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a simplified schematic diagram of the bag forming device disclosed herein;

[0030] Figure 2 A simplified exploded perspective view of a bag forming device according to an embodiment of the present disclosure;

[0031] Figure 3 A flow chart illustrating a bag forming method according to the present disclosure;

[0032] Figure 4 and Figure 5 is a process diagram of a bag forming device of a bag forming method according to one embodiment;

[0033] Figures 6 to 8 is a process diagram of a bag forming device of a bag forming method according to another embodiment;

[0034] Figure 9 The following are photos of bags of Example 1 and Comparative Example 1 made according to the bag forming method of the present disclosure.

[0035] Description of Reference Numerals

[0036] 1: Bag forming device 10: Die part

[0037] 11: Molding lower surface 12: Molding side

[0038] 13: Fixed part 14: Elastic part

[0039] 15: Vacuum hole 16: Vacuum device

[0040] 20: Stamping part 30: Forming support part

[0041] 40: Stripper 50: Control unit

[0042] S: Forming groove P: Bag sheet DETAILED DESCRIPTION

[0043] Deep drawing is commonly used to manufacture pouch-type batteries. Deep drawing is a pouch-forming process that uses a mold to create the pouch according to the shape of a pre-made mold. However, deep drawing has the following problems: cracks and tears may occur in the pouch due to material limitations when forming beyond a certain depth.

[0044] The present disclosure will be described in detail below with reference to the accompanying drawings. However, this is merely illustrative, and the present disclosure is not limited to the specific embodiments described illustratively.

[0045] Bag forming device

[0046] Figure 1 FIG. 1 is a schematic diagram of the bag forming device 1 disclosed herein. Figure 1 An implementation example of the present disclosure can provide a bag forming device 1, which can prevent cracks from occurring at the corners of the bag and prevent the bag from expanding.

[0047] Figure 2 1 is a simplified exploded perspective view of a bag forming apparatus 1 according to an embodiment of the present disclosure. While the bag sheet P used in the present disclosure is shown in the figure, this is for ease of understanding; the bag forming apparatus 1 of the present disclosure may not include the bag sheet P.

[0048] The bag forming device 1 may include: a die portion 10, provided with a forming groove S; a punching portion 20, arranged to face the forming groove S and configured to move relative to the forming groove S; a forming support portion 30, configured to move relative to the punching portion 20 inside the forming groove S; and a control portion 50, adjusting the moving speed of at least one of the forming support portion 30 and the punching portion 20.

[0049] The die portion 10 may include: forming inner surfaces 11 and 12 forming a forming groove S; and a fixing portion 13 disposed around the forming groove S for placing the bag sheet P. Figure 2 In the figure, multiple forming grooves S are shown, indicating that multiple cup portions can be formed from one bag sheet P. However, this is only for ease of understanding and the present disclosure is not limited thereto. That is, even if only at least one forming groove S is formed, it should be considered as belonging to the present disclosure.

[0050] The bag sheet P can be formed on the molded lower surface 11. The molded lower surface 11 may be recessed inward to form the overall shape of the main cavity or air cavity (hereinafter referred to as the housing portion) that constitutes the secondary battery bag. The molded lower surface 11 may be shaped to easily accommodate the descending punch 20. The shape of the molded lower surface 11 can be tailored to the desired housing portion. For example, one embodiment of the molded lower surface 11 may be a rectangular parallelepiped, but this is not limiting.

[0051] The die portion 10 may further include an elastic portion 14. The elastic portion 14 may be disposed along the height direction of the molding lower surface 11. The elastic portion 14 is not particularly limited as long as it is made of an elastic material. At least one elastic portion 14 may be disposed on the bottom surface of the molding lower surface 11, and more specifically, two or more elastic portions may be disposed.

[0052] The molding support portion 30 can be disposed on the elastic portion 14, and specifically can be fixed to the upper portion of the elastic portion 14. The molding support portion 30 can descend together with the elastic portion 14 when it descends, and can ascend together with the elastic portion 14 when it ascends.

[0053] The molding support portion 30 may be spaced apart from the molding lower surface 11. The molding groove S formed by the molding lower surface 11 and the molding side surface 12 may form an internal space through the molding support portion 30. The internal space may be a space in which a vacuum pressure is formed by the vacuum device 16 described below. The molding support portion 30 may rise or fall within the die portion 10 along the molding side surface 12. The side surface of the molding support portion 30 may be in close contact with the molding side surface 12 with no space between them. The molding support portion 30 may remain in close contact with the molding side surface 12 when rising or falling within the die portion 10.

[0054] The forming support 30 is a structure that supports the bottom of the bag sheet P during the bag forming process and bends the bag sheet P. The bag sheet P can be placed on the forming support 30. The bag sheet P can descend together with the forming support 30 when the forming support 30 descends, and can ascend together with the forming support 30 when the forming support 30 ascends.

[0055] The die portion 10 may include a fixing portion 13, which may be connected to the molding side surface 12 and configured to be parallel to the molding lower surface 11 at the upper portion of the molding side surface 12, and may be separated from the molding support portion 30 at a constant interval and configured on the same plane as the molding support portion 30.

[0056] The bag sheet P can be arranged on the fixing portion 13 and the forming support portion 30. Moreover, the bag sheet P arranged on the fixing portion 13 can be fixed so as not to move, and the bag sheet P arranged on the forming support portion 30 can move together with the up and down movement of the forming support portion 30.

[0057] Reference Figure 1 and Figure 2 The bag forming apparatus 1 of the present disclosure may further include a stripper 40. The stripper 40 is disposed at a distance from the fixing portion 13 to secure the bag sheet P, thereby pressing the upper portion of the bag sheet P. The stripper 40 may be disposed above the fixing portion 13 at a distance corresponding to the thickness of the bag sheet P. Furthermore, the stripper 40 may be formed with a hole shaped according to the shape of the punching portion 20, so that the punching portion 20 can pass through when the punching portion 20 is lowered.

[0058] The bag sheet P fixed by the fixing portion 13 can be fixed in a state where all parts except the center portion are fixed. The center portion of the bag sheet P can descend as the forming support portion 30 descends, while the side portions of the bag sheet P are fixed by the fixing portion 13, and the bag sheet P can be formed so that only the center portion of the bag sheet P protrudes downward. The center portion of the bag sheet P can rise as the forming support portion 30 ascends, while only the side portions of the bag sheet P are fixed by the fixing portion 13, and the center portion of the bag sheet P can be formed so that it protrudes upward.

[0059] In one embodiment of the present disclosure, the die portion 10 may further include an internal space formed by the molding groove S and the molding support portion 30, and may further include a vacuum device 16 for creating a vacuum pressure in the internal space. The die portion 10 may be connected to the vacuum device 16 via a vacuum hole 15 formed in the molding lower surface 11. The vacuum device 16 is not particularly limited as long as it can create a vacuum pressure in the molding groove S through vacuum suction.

[0060] On the other hand, the term "vacuum pressure" as used herein refers to the vacuum device 16 providing a pressure lower than the surrounding atmospheric pressure, thereby drawing air and the like surrounding the mold tank S into the vacuum device 16 through the vacuum holes 15. This term also encompasses negative pressure. Specifically, the vacuum device 16 can create a vacuum pressure within the mold tank S, drawing the mold support 30 into the vacuum holes 15 and causing it to adhere tightly to the mold support 30.

[0061] When the vacuum device 16 creates a vacuum in the molding groove S, the molding support 30 can be lowered toward the molding lower surface 11. As the molding support 30 descends, a vacuum is created in the enclosed space between the molding support 30, the molding side surface 12, and the bag sheet P. Leveraging the vacuum pressure between the molding support 30, the molding side surface 12, and the bag sheet P, the center of the bag sheet P can also be lowered along with the molding support 30. The side surfaces of the bag sheet P are secured by the stripper 40 and the securing portion 13, allowing only the center of the bag sheet P to be pressurized and molded.

[0062] The punching part 20 is disposed separately on the forming support part 30 . As the punching part 20 descends toward the bag sheet P, it can pressurize and form the center of the bag sheet P toward the forming lower surface 11 .

[0063] The bag forming apparatus of the present disclosure may include a control unit 50 for adjusting the movement speed of at least one of the forming support unit 30 and the punching unit 20. The control unit 50 may be connected to the die unit 10 and the punching unit 20. Specifically, the control unit 50 may be connected to the die unit 10 and at least one of the forming support unit 30 and the vacuum device 16 to adjust the speed of the forming support unit 30 and the vacuum pressure of the vacuum device 16.

[0064] The control unit 50 can adjust the distance between the forming support 30 and the punching unit 20 by adjusting the moving speed of the forming support 30 and the punching unit 20. Specifically, the control unit 50 can be connected to the vacuum device 16, the punching unit 20, and the forming support 30, and can adjust the descending speed of the punching unit 20 and the distance between the forming support 30 and the punching unit 20 based on the descending speed of the forming support 30 based on the vacuum pressure formed by the vacuum device 16. The descending or ascending speed of the punching unit 20 and the forming support 30 and the distance between the forming support 30 and the punching unit 20 will be described in the subsequent bag forming method.

[0065] Bag forming method

[0066] Another implementation example of the present disclosure provides a bag forming method, which can prevent cracks from occurring at bag corners and prevent bag expansion. Another implementation example of the present disclosure is described in detail below.

[0067] Figure 3 Flowchart showing the bag forming method of the present disclosure. Figure 3As another implementation example of the present disclosure, a bag forming method may include: a configuration step of configuring a bag sheet P between a die portion 10 and a punching portion 20, wherein the die portion 10 includes a molding lower surface 11 for molding the bag sheet P and a molding support portion 30 configured on the molding lower surface 11, and the punching portion 20 is used to mold the bag sheet P; a primary molding step of vacuuming the internal space of the die portion 10 so that the molding support portion 30 descends toward the molding lower surface 11 to bend the bag sheet P; and a secondary molding step of descending the punching portion 20 toward the molding lower surface 11 to pressurize the bag sheet P.

[0068] The bag forming method of an implementation example may include a placement step S1 . The placement step S1 may be a step of placing the bag sheet P on the forming support 30 , specifically, a step of placing the center portion of the bag sheet P on the forming support 30 .

[0069] Furthermore, the arranging step S1 may be a step of arranging the bag sheet P on the fixing portion 13 . Specifically, the arranging step S1 may be a step of arranging the side surface of the bag sheet P on the fixing portion 13 .

[0070] The arrangement step S1 may further include a step of fixing the bag sheet P. The die portion 10 may further include a fixing portion 13 that functions as a support platform for fixing the bag sheet P. A stripper 40 may be arranged on the bag sheet P arranged on the fixing portion 13 to fix the side portions of the bag sheet P by the stripper 40, and the center portion of the bag sheet P may be arranged on the forming support portion 30.

[0071] The bag forming method of an implementation example may include a primary forming step S2. The primary forming step S2 may be a step of bending the bag sheet P.

[0072] The primary forming step S2 may be a step in which as the forming support 30 descends, the center of the bag sheet P in close contact with the forming support 30 descends together with the forming support 30 so that the bag sheet P is bent into a downwardly protruding shape.

[0073] During the primary molding step S2, the molding support 30 can be lowered toward the molding lower surface 11 by vacuum pressure. Specifically, by creating a vacuum in the internal space between the molding lower surface 11 and the molding support 30, the molding support 30 can be lowered toward the bottom of the molding lower surface 11 by vacuum pressure. Simultaneously, a vacuum is also created between the molding support 30 and the bag sheet P, allowing the bag sheet P to descend along with the molding support 30. During vacuum molding of the bag sheet P, the stress of the aluminum within the bag sheet P is dispersed, thereby reducing the concentrated stress on the bag sheet P. This prevents cracking and tearing of the bag sheet P during the bag molding process. Furthermore, during vacuum molding, as the concentrated stress on the bag sheet P is reduced, the housing portion can be formed deeper, thereby enabling the production of thicker pouch-type secondary batteries and thereby increasing the energy density of the secondary battery.

[0074] The bag forming method of an implementation example may further include a secondary forming step S3 . The secondary forming step S3 may be a step of pressurizing the upper portion of the bag sheet P bent in the primary forming step S2 to form a receiving portion.

[0075] The punching unit 20 is a device for forming the bag sheet P and is spaced apart from the forming support 30. Furthermore, the punching unit 20 can pressurize the upper portion of the bent bag sheet P as the forming support 30 descends. This pressurization of the upper portion of the bag sheet P forms a receiving portion for the bag sheet P.

[0076] In the secondary molding step S3, a housing for accommodating the electrode assembly can be formed in the bag sheet P according to the shape of the punching portion 20. Specifically, the inner side of the housing can be formed according to the shape of the punching portion 20, and the outer side of the housing can be formed according to the shape of the die portion 10. More specifically, the outer side of the housing can be formed according to the side of the molding lower surface 11 and the upper surface of the molding support portion 30. The shape of the lower surface of the housing can be formed according to the shape of the lower surface of the punching portion 20, so the lower portion of the punching portion 20 and the upper surface of the molding support portion 30 can be parallel to the bag sheet P.

[0077] The punching part 20 may be disposed on the molding support part 30 at a distance and may be structured to descend toward the molding lower surface 11 and the molding support part 30. The method of ascending and descending the punching part 20 is not particularly limited.

[0078] When the bag sheet P is formed by bending the bag sheet P under vacuum pressure, a bag expansion phenomenon may occur in the center of the bag sheet P, where the container expands due to the vacuum pressure. If the bag expansion phenomenon occurs in the container, it becomes difficult to adjust the forming depth of the container and wrinkles appear on the outer shape of the bag, which may lead to problems such as quality degradation.

[0079] Therefore, in one embodiment of the bag forming method, the bag sheet P can be formed by adjusting the interval between the forming support portion 30 and the punching portion 20. By adjusting the interval between the forming support portion 30 and the punching portion 20, the time between the primary forming step S2 and the secondary forming step S3 can be reduced, and the space required for the bag to be formed by vacuum pressing can be reduced, thereby preventing the bag from expanding in the container.

[0080] The spacing between the forming support 30 and the punching unit 20 can be adjusted by adjusting their respective speeds. Specifically, the descent and ascent speeds of the forming support 30 can be adjusted by adjusting the vacuum pressure of the lower forming surface 11. The descent and ascent speeds of the punching unit 20 can be adjusted by the control unit 50 based on the spacing between the forming support 30 and the punching unit 20.

[0081] Figure 4 and Figure 5 FIG. 1 is a process diagram of a bag forming device 1 according to a bag forming method according to an embodiment. Figure 4 and Figure 5 In one embodiment of the present disclosure, the primary molding step S2 and the secondary molding step S3 may be performed simultaneously.

[0082] According to one embodiment of the present disclosure, the descending speed of the forming support 30 may be the same as the descending speed of the punching part 20. For example, the gap between the forming support 30 and the punching part 20 may be kept constant to form the bag.

[0083] According to one embodiment of the present disclosure, the descending speed of the punching portion 20 may be faster than the descending speed of the forming support portion 30. For example, the interval between the forming support portion 30 and the punching portion 20 may gradually narrow.

[0084] Figures 6 to 8 FIG. 1 is a process diagram of a bag forming device 1 according to a bag forming method according to another embodiment of the present disclosure. Figures 6 to 8 In another embodiment of the present disclosure, the secondary molding step S3 may be performed after the primary molding step S2 is performed.

[0085] According to another embodiment of the present disclosure, the punching portion 20 may be lowered after the forming support portion 30 is lowered. For example, the interval between the forming support portion 30 and the punching portion 20 may gradually narrow after being the farthest apart.

[0086] According to another embodiment of the present disclosure, the punching unit 20 may be lowered while the forming support unit 30 is lowered and then raised again. For example, the forming support unit 30 may be lowered first, and then the punching unit 20 may be lowered while the forming support unit 30 is raised or after the forming support unit 30 is raised.

[0087] The spacing between the forming support portion 30 and the punching portion 20 can be maintained at less than 1 mm, specifically less than 0.7 mm, and more specifically less than 0.5 mm. Maintaining this range can reduce the time between the primary forming step S2 and the secondary forming step S3, and reduce the space required for vacuum forming of the bag, thereby preventing bag expansion in the container.

[0088] On the other hand, if the interval between the forming support portion 30 and the punching portion 20 exceeds 1 mm, it may be difficult to form a vacuum pressure, and the bag expansion area increases, thereby causing the main cavity bag to expand.

[0089] An implementation example of the present disclosure may further include a speed adjustment step S4 of adjusting the speed of at least one of the forming support portion 30 and the punching portion 20 by the control portion 50. In the speed adjustment step S4, the control portion 50 may be connected to the die portion 10 and the punching portion 20. Specifically, the control portion 50 may be connected to the die portion 10 and at least one of the forming support portion 30 and the vacuum device 16 to adjust the speed of the forming support portion 30, and the vacuum pressure of the vacuum device 16 may be adjusted.

[0090] lithium secondary batteries

[0091] According to another implementation example of the present disclosure, a secondary battery may be provided. The secondary battery includes a receiving portion formed by the pouch forming method and an electrode assembly received in the receiving portion.

[0092] According to exemplary embodiments, an electrode assembly may be formed by repeatedly arranging a positive electrode, a negative electrode, and a separator. In some embodiments, the electrode assembly may be a winding type, a stacking type, a z-folding type, or a stack-folding type.

[0093] The positive electrode may include a positive electrode current collector and a positive electrode mixture layer disposed on at least one side of the positive electrode current collector. For example, the positive electrode current collector may include stainless steel, nickel, aluminum, titanium, or alloys thereof, but is not particularly limited.

[0094] The positive electrode mixture layer may include a positive electrode active material. The positive electrode active material may include a compound capable of reversibly intercalating and deintercalating lithium ions, such as lithium cobalt-based oxide particles (LCO), lithium manganese-based oxide particles (LMO), lithium nickel-based oxide particles (LNO), lithium nickel cobalt manganese-based oxide particles (NCM), lithium nickel cobalt aluminum-based oxide particles (NCA), lithium iron phosphate-based oxide particles (LFP), overlithiated oxide particles (OLO), etc., but is not particularly limited.

[0095] The negative electrode may include a negative electrode current collector and a negative electrode mixture layer disposed on at least one surface of the negative electrode current collector, and is not particularly limited as long as it is a commonly used negative electrode.

[0096] The separator may be disposed between the positive electrode and the negative electrode. The separator may be configured to prevent electrical short circuit between the positive electrode and the negative electrode, thereby allowing ion flow. According to an embodiment, the thickness of the separator may be 10 μm to 20 μm, but the present disclosure is not limited thereto.

[0097] For example, the electrode tabs (positive and negative) may extend from the positive and negative current collectors, respectively, to a side of the casing. The electrode tabs may be welded to the side of the casing and connected to electrode leads (positive and negative leads) that extend or are exposed outside the casing.

[0098] The housing may be a pouch-shaped housing, a square-shaped housing, a cylindrical-shaped housing, a coin-shaped housing, etc., and may be a pouch-shaped housing in particular. The pouch-shaped housing may be in the form of a bag-shaped outer material surrounding the electrode assembly.

[0099] The bag-type external packaging material may include a metal layer, a sealant layer disposed on the bottom surface of the metal layer, and a base material layer disposed on the upper surface of the metal layer.

[0100] The bottom surface of the metal layer may face the inner side of the secondary battery or battery cell, and the top surface of the metal layer may face the outer side of the secondary battery or battery cell.

[0101] The metal layer may serve as a barrier that provides moisture resistance, chemical resistance, and gas barrier properties to the exterior material. For example, the metal layer may be made of a metal foil such as aluminum foil (Al foil).

[0102] The sealant layer may be a layer exposed to the inner side of the battery cell. The sealant layer may be a portion that is melted and joined together after the electrode assembly is housed within the exterior packaging material through a sealing process, including a welding process. For example, the sealant layers included in the upper and lower bags may be welded to each other to form a sealed portion.

[0103] For example, the sealant layer may include a polyolefin resin or a cyclic polyolefin resin. Examples of the polyolefin resin include polyethylene, polypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), and ethylene-butene-propylene terpolymers.

[0104] The substrate layer may include an intermediate substrate layer and an outer substrate layer. The intermediate substrate layer and the outer substrate layer may be sequentially stacked from the upper surface of the metal layer.

[0105] The substrate layer may include polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicone resin, phenolic resin, and mixtures or copolymers thereof.

[0106] Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyesters, and polycarbonates. Examples of the polyamide resin include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 6,10, and poly(m-xylylene adipamide) (MXD6).

[0107] For example, the middle base material layer may include a polyamide resin such as nylon, and the outer base material layer may include a polyester resin such as polyethylene terephthalate (PET).

[0108] For example, the above-mentioned layers or films may be adhered to each other via an adhesive layer.

[0109] Example

[0110] The embodiments of the present invention are further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are merely illustrative of the present invention and do not limit the scope of the appended claims. Various changes and modifications may be made to the embodiments within the scope of the present disclosure and the scope of the technical concept, which will be obvious to those skilled in the art, and such variations and modifications naturally fall within the scope of the appended claims.

[0111] Manufacturing Example

[0112] Examples 1 to 5 and Comparative Examples 1 to 4

[0113] After placing a bag sheet made of aluminum (Al) with a thickness of 0.15 mm on the forming support part and the fixing part, a peeler was placed on the fixing part to fix the side surface of the bag sheet.

[0114] The pressure of the molding tank is reduced to 10 by the vacuum device connected to the vacuum hole on the lower surface of the molding. -5 Torr or less, so that the forming support part and the center of the bag sheet are lowered toward the forming lower surface together.

[0115] As the forming support portion descends, the punching portion is lowered while the control portion constantly maintains the interval between the forming support portion and the punching portion. The punching portion applies pressure to the upper portion of the center portion of the bag sheet to form the center portion of the bag sheet, thereby forming a receiving portion.

[0116] Here, the distance between the lowered forming support and the punching part was kept constant according to the distance in Table 1 below.

[0117]

Table 1

[0118]

[0119] Evaluation Example

[0120] The degree of bag expansion of Examples 1 to 5 and Comparative Examples 1 to 4 was confirmed by measuring the height difference between the corners of the bag housing portion and the center of the bag housing portion, and the results are shown in Table 2 below.

[0121] On the other hand, the bag expansion phenomenon of Example 1 and Comparative Example 1 was photographed and shown in FIG. Figure 9 .

[0122]

Table 2

[0123]

[0124] With reference to Table 2, it can be confirmed that the bag expansion degree of Examples 1 to 5 in which the interval between the forming support portion and the punching portion is 1 mm or less is low, and the bag expansion phenomenon of the bag is alleviated.

[0125] On the contrary, it can be confirmed that the bag expansion degree of Comparative Examples 1 to 4 in which the interval between the forming support portion and the punching portion exceeds 1 mm is high, and the bag expansion phenomenon occurs.

[0126] Reference Figure 9 , it can be confirmed with the naked eye that, compared with Example 1, the bag expansion phenomenon occurs in Comparative Example 1 in which the interval between the forming support portion and the punching portion is longer.

[0127] The above description is only an example of applying the principles of the present disclosure, and other configurations may be included without departing from the scope of the present invention.

Claims

1. A bag forming method comprising: a step of arranging the bag sheet between a die portion and a punching portion, wherein the die portion includes a molding lower surface for molding the bag sheet and a molding support portion arranged on the molding lower surface, and the punching portion is used to mold the bag sheet; a primary forming step of vacuuming the inner space of the die portion to lower the forming support portion toward the forming lower surface to bend the bag sheet; and A secondary molding step is performed in which the punching portion is lowered toward the molding lower surface to apply pressure to the bag sheet.

2. The bag forming method according to claim 1, wherein the primary forming step and the secondary forming step are performed simultaneously. 3 . The bag forming method according to claim 1 , wherein the secondary forming step is performed after the primary forming step is performed. 4 . The bag forming method according to claim 2 , wherein at least one of the forming support portion and the punching portion descends at a constant speed. The bag forming method according to claim 2 , wherein the pressing portion descends faster than the forming support portion. The bag forming method according to claim 3 , wherein the punching part descends after the forming support part is completely descended. 7 . The bag forming method according to claim 3 , wherein the forming support portion descends and then ascends again while the punching portion descends. 8 . The bag forming method according to claim 1 , wherein the interval between the forming support portion and the punching portion is maintained at 1 mm or less.

9. The bag forming method according to claim 1, further comprising: A speed adjustment step of controlling the moving speed of at least one of the forming support portion and the punching portion by a control portion.

10. The bag forming method according to claim 1, wherein the bag sheet bent in the primary forming step is bent to protrude downward. 11 . The bag forming method according to claim 1 , wherein in the secondary forming step, a receiving portion for receiving the electrode assembly is formed on the bag sheet according to the shape of the punching portion. 12 . A lithium secondary battery comprising a pouch manufactured by the pouch forming method according to claim 1 .

13. A bag forming device comprising: The die portion is provided with a forming groove; a punching portion disposed so as to face the molding groove and configured to move relative to the molding groove; a forming support portion configured to move relative to the punching portion within the forming groove; and The control unit adjusts the moving speed of at least one of the forming support unit and the punching unit.

14. The bag forming device according to claim 13, wherein the die portion further comprises an inner space formed by the forming groove and the forming support portion. Also included is a vacuum device for forming a vacuum pressure in the internal space.

15. The bag forming device according to claim 13, wherein the die portion further comprises a fixing portion for configuring the bag sheet.

16. The bag forming apparatus according to claim 15, further comprising: The stripper is disposed on the fixing portion at a distance and is used to fix the bag sheet.

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