Device and system for forming bags

Abstract

Bag forming system, including: A formed bag plate, obtained in an arranging process of arranging a bag plate between a die section, which is a lower forming surface on which a bag plate is formed, and a forming support section, which is arranged on the lower forming surface, and a punch section for forming the bag plate; and in a first forming process of evacuating an interior space of the die section and lowering the forming support section in one direction of the lower forming surface to bend the bag plate; and a second forming process of lowering the stamp section in a direction of the lower forming surface to press the bag plate.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device and a system for forming pouches. BACKGROUND

[0002] Unlike a primary battery, which cannot be recharged, a general secondary battery is a battery that can be charged and discharged with electricity and is widely used in electronic devices such as mobile phones, laptops, camcorders, and the like, as well as electric vehicles. Specifically, a lithium secondary battery has an operating voltage of about 3.6V, a capacity about three times that of a nickel-cadmium battery or a nickel-hydrogen battery, which are widely used as power sources for electronic devices. Because lithium secondary batteries have a high energy density per unit weight, their utilization rate tends to increase explosively.

[0003] A secondary battery can be divided into a coin-shaped battery, a cylindrical battery, a prismatic battery, and a pouch-shaped battery depending on the shape of the battery case. In a secondary battery, an electrode assembly arranged in the battery case is a power generating element that can be charged and discharged. The electrode assembly consists of a stacked structure of electrodes and a separator.

[0004] The electrode assembly can be roughly classified into jelly roll type in which a separator is inserted between plate-like cathodes and anodes coated with an active material, stack type in which a plurality of cathodes and anodes are stacked one after another with a separator inserted therebetween, and stack / fold type in which stacked unit cells are wound with a long separator film.

[0005] Recently, a bag-shaped battery having a structure in which a stack-like or stack / fold-like electrode assembly is embedded in a bag-shaped battery case made of aluminum laminate plates has attracted widespread attention due to its low manufacturing cost, light weight, and easy molding, and its use is gradually increasing. SUMMARY

[0006] One aspect of the invention relates to a bag forming apparatus and a bag forming system for preventing tears in a corner portion of a bag.

[0007] Another aspect of the invention relates to a bag forming apparatus and a bag forming system for preventing a bag expansion phenomenon.

[0008] In yet another aspect, the invention relates to a bag-shaped secondary battery formed by a bag forming system.

[0009] According to yet another aspect of the invention, a bag forming system comprises: a bag plate disposed between a die portion having a lower forming surface on which a bag plate is formed and a forming support portion disposed on the lower forming surface, and a punch portion for forming the bag plate; a bent bag plate obtained in a first forming process of evacuating an interior of the die portion and lowering the forming support portion in a direction of the lower forming surface; and a pressed bag plate obtained in a second forming process of lowering the punch portion in a direction of the lower forming surface to press the bag plate.

[0010] The first forming process and the second forming process can be carried out simultaneously.

[0011] After the first forming process has been completed, the second forming process can be carried out.

[0012] At least one of the forming support section and the punch section can be lowered at a constant speed.

[0013] The lowering speed of the punch section can be faster than the lowering speed of the forming support section.

[0014] After the lowering of the forming support section is completed, the punch section can be lowered.

[0015] The forming support section can be lowered and then raised again, thereby lowering the punch section.

[0016] The distance between the forming support section and the punch section can be set or maintained at 1 mm or less.

[0017] The bag forming system according to one aspect of the invention may further include a control unit for a speed control operation of controlling a moving speed of at least one of the forming support portion and the punch portion.

[0018] The bag plate bent in the first forming process may be convexly curved downwards.

[0019] In the second forming process, a receiving portion in which an electrode assembly is received may be formed in the bag plate to have the same shape as the outer shape of the punch portion.

[0020] According to another aspect of the invention, a lithium secondary battery includes a pouch formed by the pouch forming system described above.

[0021] According to another aspect of the invention, a bag forming apparatus includes: a die portion having a forming groove; a punch portion disposed to oppose the forming groove and provided to move relative to the forming groove; a forming support portion provided to move relative to the punch portion within the forming groove; and a control unit for controlling the moving speed of at least one of the forming support portion and the punch portion.

[0022] The die portion may further include an inner space formed by the forming groove and the forming support portion, and may further include a vacuum device that generates a vacuum pressure in the inner space.

[0023] The die section may also include a fixing section on which a bag plate is arranged.

[0024] A bag forming apparatus according to another aspect of the invention may further include a stripper disposed to be spaced apart from the fixing portion and fixing a bag plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Certain aspects, features and advantages of the invention may be illustrated by the following detailed description with reference to the accompanying drawings. Fig. Figure 1 is a schematic representation of a bag forming apparatus according to the present invention. Fig. 2 is a schematic exploded perspective view of a bag forming apparatus according to an embodiment of the present invention. Fig. 3 is a diagram illustrating a bag forming system according to the present invention. Fig. 4 and Fig.5 are diagrams of a bag forming apparatus according to a bag forming system in one embodiment. Fig. 6 to 8 are diagrams of a bag forming apparatus according to a bag forming system of another embodiment. Fig. 9 is a picture of a bag obtained by comparing Example 1 and Comparative Example 1 produced by the bag forming system according to the present invention. DETAILED DESCRIPTION

[0026] A deep drawing process is generally used to form a pouch-shaped battery. A deep drawing process is a method of forming a pouch using a mold and is a technology for forming a pouch according to the shape of a pre-formed mold. However, the deep drawing process can be problematic in that, due to material limitations, cracks and breakages may occur in the pouch if the pouch is formed beyond a certain depth.

[0027] The present invention will now be described in detail with reference to the drawings. However, this is only an example, and the present invention is not limited to the specific embodiments described herein. Device for forming bags

[0028] Fig. 1 is a schematic representation of a bag forming apparatus 1 according to the present invention. Referring to Fig. 1, in one embodiment of the present invention, a bag forming apparatus 1 can be provided which can prevent cracks in a corner portion of a bag and a bulging phenomenon of the bag.

[0029] Fig. 2 is a schematic exploded perspective view of a bag forming apparatus 1 according to an embodiment of the present invention. Although a bag plate P used in the present invention is also shown in the drawings, it is shown only for convenience of understanding, and the bag forming apparatus 1 of the present invention may not include the bag plate P.

[0030] The bag forming apparatus 1 may include a die portion 10 having a forming groove S; a punch portion 20 disposed to face the forming groove S and provided to move relative to the forming groove S; a forming support portion 30 provided to move relative to the punch portion 20 within the forming groove S; and a control unit 50 for controlling a moving speed of the forming support portion 30 and / or the punch portion 20.

[0031] The die section 10 may include forming inner surfaces 11 and 12 forming a forming groove S, and a fixing section 13 arranged around the forming groove S, on which the bag plate S is arranged. In Fig.2, it is shown that a plurality of forming grooves S are provided to form a plurality of container sections with a single bag plate P, but this is for convenience only, and the present invention is not limited thereto. That is, even if at least one forming groove S is formed, it should be considered part of the present invention.

[0032] A pouch plate P can be formed on the lower forming surface 11. The lower forming surface 11 may have a structure that is depressed inward to form an overall shape of a main body portion or a gas space (hereinafter referred to as an accommodating portion) that forms a pouch of a secondary battery. The lower forming surface 11 may have a shape that makes it easy to receive the descending punch portion 20. The shape of the lower forming surface 11 may be made according to the shape of the accommodating portion to be formed. For example, one embodiment of the lower forming surface 11 may have a rectangular parallelepiped shape, but one embodiment is not limited thereto.

[0033] The die section may further include an elastic section 14. The elastic section 14 may be arranged on the lower forming surface 11 in the height direction. The material of the elastic section 14 is not particularly limited as long as it is an elastic material. The at least one elastic section 14 may be arranged on a lower surface of the lower forming surface 11, and in particular, two or more elastic sections 14 may be arranged.

[0034] The molding support portion 30 may be disposed on the elastic portion 14, and in particular, the molding support portion 30 may have a shape in which the molding support portion 30 is specifically fixed to an upper portion of the elastic portion 14. The molding support portion 30 may be lowered along with the lowering of the elastic portion 14 and may be raised along with the raising of the elastic portion 14.

[0035] The molding support portion 30 may be arranged so as to be spaced apart from a lower molding surface 11. A molding groove S formed by a lower molding surface 11 and a side molding surface 12 may form an internal space through the molding support portion 30. The internal space may be a space in which a negative pressure is generated by a negative pressure device 16 to be described later. The molding support portion 30 may be raised or lowered inside the die portion 10 along the side molding surface 12. The distance between a side surface of the molding support portion 30 and the side molding surface 12 may be so large that there is no empty space, and the molding support portion 30 may be maintained in a state of close contact with the side molding surface 12 while being raised or lowered within the die portion 10.

[0036] The forming support portion 30 is configured to support a lower surface of the bag plate P during the bag forming process and to bend the bag plate P, and the bag plate P can be disposed on the forming support portion 30. The bag plate P can be lowered together with the forming support portion 30 when the forming support portion 30 is lowered, and can be raised together with the forming support portion 30 when the forming support portion 30 is raised.

[0037] The die portion 10 may include a fixing portion 13, the fixing portion may be connected to the lateral forming surface 12 and may be arranged parallel to the lower forming surface 11 in an upper portion of the lateral forming surface 12, and may be spaced from the forming support portion 30 by a predetermined distance and arranged in the same plane as the forming support portion 30.

[0038] A bag plate P can be arranged on the fixing section 13 and the forming support section 30. Furthermore, the bag plate P arranged on the fixing section 13 can be fixed without being moved, and the bag plate P arranged on the forming support section 30 can be moved along with the upward and downward movement of the forming support section 30.

[0039] With reference to the Fig. 1 and Fig.2, the bag forming apparatus 1 of the present invention may further include a scraper 40 arranged to be spaced from the fixing portion 13 and presses the upper portion of the bag plate P to fix the bag plate P. The scraper 40 may be arranged to be spaced from an upper surface of the fixing portion 13 by a thickness of the bag plate P. Furthermore, the scraper 40 may have a hole formed therein corresponding to the shape of the punch portion 20 so that the punch portion 20 can pass therethrough when the punch portion 20 is lowered.

[0040] The bag plate P fixed by the fixing portion 13 can be fixed except for a central portion of the bag plate P. When the forming support portion 30 is lowered, the central portion of the bag plate P can be lowered, a side portion of the bag plate P can be fixed by the fixing portion 13, and only the central portion of the bag plate P can be formed downwardly convex. When the forming support member 30 is raised, the central portion of the bag plate P can be raised, and only the side portion of the bag plate P can be fixed by the fixing member 13, and the central portion of the bag plate P can be formed upwardly convex.

[0041] In one embodiment of the present invention, the die portion 10 may further include an internal space formed by the forming groove S and the forming support portion 30, and may further include a vacuum device 16 that generates a vacuum pressure in the internal space. The die portion 10 may be connected to the vacuum device 16 through a vacuum hole 15 formed in the lower forming surface 11. The vacuum device 16 is not particularly limited, as long as the vacuum device 16 is a device that can generate a vacuum pressure in the forming groove S by vacuum suction.

[0042] Meanwhile, the term "vacuum pressure" as used in the present invention refers to a pressure lower than the atmospheric pressure in a surrounding area, so that air around the forming groove S is sucked into the vacuum device 16 through a vacuum hole 15, which may have a meaning including negative pressure. That is, the vacuum device 16 may generate a vacuum pressure in the forming groove S so that the forming support portion 30 is sucked onto the vacuum hole 15 and held thereby.

[0043] When a vacuum pressure is generated in the forming groove S by the vacuum device 16, the forming support portion 30 can be lowered toward the lower forming surface 11. When the forming support portion 30 is lowered, a vacuum pressure can be generated in a sealed space between the forming support portion 30, the side forming surface 12, and the bag plate P. By the vacuum pressure between the forming support portion 30, the side forming surface 12, and the bag plate P, a central portion of the bag plate P can also be lowered together with the forming support portion 30, and a side portion of the bag plate P can be fixed by the stripper 40 and the fixing portion 13, so that only the central portion of the bag plate P can be pressed and formed.

[0044] The punch portion 20 is arranged to be spaced apart from the forming support portion 30, and when the punch portion 20 is lowered in a direction of the bag plate P, the central portion of the bag plate P can be pressed and formed in a direction of the lower forming surface 11.

[0045] The bag forming apparatus of the present invention may include a control unit 50 for controlling the movement speed of the forming support section 30 and / or the punch section 20. The control unit 50 may be connected to the die section 10 and the punch section 20, and may specifically be connected to at least one of the forming support section 30 and a vacuum device 16 in the die section 10 to control a speed of the forming support section 30 and the vacuum pressure of the vacuum device 16.

[0046] The control unit 50 can control the distance between the forming support section 30 and the punch section 20 by controlling the moving speed of the forming support section 30 and the punch section 20. Specifically, the control unit 50 can be connected to the vacuum device 16, the punch section 20, and the forming support section 30, and can control a lowering speed of the punch section 20 and the distance between the forming support section 30 and the punch section 20 according to the lowering speed of the forming support section 30 depending on the vacuum pressure generated by the vacuum device 16. The lowering or raising speed of the punch section 20 and the forming support section 30, as well as the distance between the forming support section 30 and the punch section 20, will be described later in the bag forming system. Bag forming system

[0047] Another embodiment of the present invention is to provide a bag forming system that can prevent cracks in a corner portion of a bag and the phenomenon of bag bulging. Another embodiment of the present invention will be specifically described below.

[0048] Fig. 3 is a flow chart illustrating a bag forming system according to the present invention. Referring to Fig.3, a bag forming system which is another embodiment of the present invention includes a bent bag plate P obtained by means of a process of disposing a bag plate P between a die portion 10 having a lower forming surface 11 on which a bag plate P is formed, a forming support portion 30 disposed on the lower forming surface 11, and a punch portion 20 for forming the bag plate P; a first forming process of evacuating an internal space of the die portion 10 and lowering the forming support portion 20 in a direction of the lower forming surface 11 to bend the bag plate P; and a second forming process of lowering the punch portion 20 in a direction of the lower forming surface 11 to press the bag plate P.

[0049] A bag forming system of one embodiment is arranged a central portion of the bag plate P on the forming support section 30 and is obtained by means of an arranging process (S1). The arranging process (S1) may be a process of arranging a bag plate P on the forming support section 30, and in particular, it may be a process of arranging a central portion of the bag plate P on the forming support section 30.

[0050] Furthermore, the arranging process (S1) may be a process of arranging a bag plate P on a fixing portion 13. Specifically, the arranging process (S1) may be a process of arranging a side portion of the bag plate P on the fixing member 13.

[0051] The arranging process (S1) may further include a process for fixing the bag plate P. The die section 10 may further include a fixing section 13 serving as a support for fixing the bag plate P. A stripper 40 may be arranged on the bag plate P, which is arranged on the fixing section 13 so that a side portion of the bag plate P can be fixed by the stripper 40, and a central portion of the bag plate P may be arranged on the forming support section 30.

[0052] In one embodiment, a bag forming system may include a bent bag sheet P obtained in a first forming process (S2). The first forming process (S2) may be a process of bending a bag sheet P.

[0053] In the first forming process (S2), the bag plate P may be convexly bent downward by lowering the forming support portion 30 and, at the same time, lowering the central portion of the bag plate P, which is in close contact with the forming support portion 30, along the forming support portion 30.

[0054] In the first forming process (S2), the forming support portion 30 may be lowered toward the lower forming surface 11 by vacuum pressure. Specifically, an internal space between the lower forming surface 11 and the forming support portion 30 may be vacuumized, so that the forming support portion 30 can be lowered to a lower surface of the lower forming surface 11 by vacuum pressure, and at the same time, a vacuum pressure may also be formed between the forming support portion and the bag plate P, so that the bag plate P can be lowered together with the forming support portion 30. When the bag plate P is formed under vacuum pressure, the stress of the aluminum within the bag plate P is dispersed, thereby reducing the concentrated stress exerted on the bag plate P, thereby preventing breakage and cracking of the bag plate P that occur during the bag forming process.In addition, since the concentrated stress acting on the bag plate P is reduced during vacuum pressure forming, a receiving portion can be formed deeper, so that a thick bag-shaped secondary battery can be manufactured and thus the energy density of the secondary battery can be improved.

[0055] A bag forming system includes a shaped receiving portion, which in one embodiment is obtained by a second forming process (S3). The second forming process (S3) may be a process for forming a receiving portion by pressing an upper portion of the bag plate that was bent by the first forming process (S2).

[0056] The punch portion 20 is a device for forming a bag plate P and can be arranged to be spaced apart from the forming support portion 30. Furthermore, the punch portion 20 can press the upper portion of the bent bag plate P when the forming support portion 30 is lowered. When the punch portion 20 presses the upper portion of the bag plate P, a receiving portion of the bag plate P can be formed.

[0057] In the second forming process (S3), a receiving portion in which an electrode assembly is received may be formed in the pouch plate P to have the same shape as the outer shape of the punch portion. Specifically, an inner surface of the receiving portion may be formed to conform to the outer shape of the punch portion 20, and an outer surface of the receiving portion may be formed to conform to the shape of the punch portion 10. Specifically, the outer surface of the receiving portion may be formed to conform to the shape of a side surface of the lower forming surface 11 and an upper surface of the forming support portion 30.

[0058] Since the shape of a lower surface of the receiving portion can be formed according to the shape of the lower surface of the punch portion 20, the lower surface of the punch portion 20 and the upper surface of the forming support portion 30 can have a shape parallel to the bag plate P. The punch portion 20 can be arranged to be spaced apart from the forming support portion 30 and can have a structure that descends in a direction of the lower forming surface 11 and a direction of the forming support portion 30. The method for raising and lowering the punch portion 20 is not particularly limited.

[0059] When forming a bag by bending the bag using vacuum pressure, a bulging phenomenon may occur in which the central portion of the bag plate P bulges due to the vacuum pressure. If a bulging phenomenon occurs in the receiving portion, it becomes difficult to control the forming depth of the receiving portion, and wrinkles may appear on the outside of the bag, which may cause problems such as poor quality.

[0060] Accordingly, in one embodiment, the bag forming system includes a bag plate P formed by controlling the distance between the forming support portion 30 and the punch portion 20.

[0061] By controlling the distance between the forming support section 30 and the punch section 20, the time between the first forming process (S2) and the second forming process (S3) can be shortened, and the space in which the bag is formed by vacuum pressure can be reduced, thereby preventing the phenomenon of bulging of the receiving section. The distance between the forming support section 30 and the punch section 20 can be controlled by controlling the speed of both the forming support section 30 and the punch section 20. Specifically, the lowering and raising speeds of the forming support section 30 can be controlled by controlling the vacuum pressure of the lower forming surface 11. The lowering and raising speeds of the punch section 20 can be controlled by the control section 50 according to the distance to the forming support section 30.

[0062] Fig. 4 and Fig.5 are diagrams of a bag forming apparatus 1 according to a bag forming system in one embodiment. Referring to the Fig. 4 and Fig. 5, an embodiment of the present invention, the first forming process (S2) and the second forming process (S3) can be performed simultaneously.

[0063] In one embodiment of the present invention, the lowering speed of the forming support section 30 and the lowering speed of the punch section 20 are the same. For example, the bag can be formed while keeping the distance between the forming support section 30 and the punch section 20 constant.

[0064] According to another embodiment of the present invention, the lowering speed of the punch portion 20 may be faster than the lowering speed of the molding support portion 30. For example, the distance between the molding support portion 30 and the punch portion 20 may become smaller.

[0065] Fig. 6 to 8 are diagrams of a bag forming apparatus 1 according to a bag forming system according to another embodiment of the present invention. Referring to Fig. 6 to 8, in another embodiment of the present invention, the second forming process (S3) may be performed after the first forming process (S2).

[0066] According to another embodiment of the present invention, after lowering the mold support portion 30, the die portion 20 may be lowered. For example, the distance between the mold support portion 30 and the die portion 20 may be increased as much as possible and then gradually decreased.

[0067] According to another embodiment of the present invention, the mold support section 30 may be lowered and then raised again, thereby lowering the die section 20. For example, the mold support section 30 may be lowered first and then the mold support section 30 may be raised simultaneously, or the die section 20 may be lowered after the mold support section 30 has been raised.

[0068] The distance between the forming support portion 30 and the punch portion 20 can be maintained at 1 mm or less, particularly at 0.7 mm or less, and particularly at 0.5 mm or less. By maintaining the above-described range, the time between the first forming process (S2) and the second forming process (S3) can be reduced, and the space in which the bag is formed by vacuum pressure can be reduced, thereby preventing a bulging phenomenon of the receiving portion.

[0069] However, if the distance between the forming support portion 30 and the punch portion 20 exceeds 1 mm, it may become difficult to generate vacuum pressure, and the expansion area of ​​the bag may increase, resulting in a main body portion bulging.

[0070] An embodiment of the present invention may further include a speed control process (S4) for controlling a speed of the mold support section 30 and / or the punch section 20 by a control unit 50. In the speed control process (S4), the control unit 50 may be connected to the die section 10 and the punch section 20, and in particular, may be connected to at least one of the mold support section 30 and a vacuum device 16 in the die section 10 to control a speed of the mold support section 30 and to be able to control the vacuum pressure of the vacuum device 16. Lithium secondary battery

[0071] According to another embodiment of the present invention, a secondary battery may be provided having a receiving portion formed by the bag forming system described above and an electrode assembly housed in the receiving portion.

[0072] According to exemplary embodiments, an electrode assembly may be formed by repeatedly arranging a cathode, an anode, and a separator. In some embodiments, the electrode assembly may be of the wound type, the stacked type, the Z-folded type, or the stacked / folded type.

[0073] The cathode may include a cathode current collector and a cathode mixture layer disposed on at least one surface of the cathode current collector. The cathode current collector may, for example, include stainless steel, nickel, aluminum, titanium, or an alloy thereof, but the present invention is not particularly limited thereto.

[0074] The cathode mixture layer may contain a cathode active material. The cathode active material may contain a compound that can reversibly intercalate and intercalate 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 phosphate iron-based oxide particles (LFP), lithium excess lithium-based oxide particles (OLO), and the like, but the present invention is not particularly limited thereto.

[0075] The anode may include an anode current collector and an anode mixture layer disposed on at least one surface of the anode current collector, but is not particularly limited as long as it is a commonly used anode.

[0076] A separator can be inserted between the cathode and the anode. The separator can be designed to prevent electrical short circuits between the cathode and the anode and to allow ion flow. Depending on the embodiment, the thickness of the separator can be 10 µm to 20 µm, but the present invention is not limited to this.

[0077] For example, electrode tabs (cathode tabs and anode tabs) can protrude from the cathode current collector and the anode current collector, respectively, and extend to one side of the housing. The electrode tabs can be fused to one side of the housing and connected to electrode leads (cathode leads and anode leads) that extend to the outside of the housing or are exposed there.

[0078] For example, a bag-shaped housing, a prismatic housing, a cylindrical housing, a coin-shaped housing, or the like can be used as the housing, but in particular, a bag-shaped housing. The bag-shaped housing can have a shape in which the outer material of the bag surrounds the electrode assembly.

[0079] The bag-shaped outer material may include a metal layer, a sealing layer arranged on a bottom side of the metal layer, and substrate layers arranged on a top side of the metal layer.

[0080] The lower surface of the metal layer may face the interior of the secondary battery or battery cell, and the upper surface of the metal layer may face the exterior of the secondary battery or battery cell.

[0081] The metal layer can serve as a barrier, imparting moisture permeability, chemical resistance, and gas barrier properties to the outer material. The metal layer can be made, for example, from a metal foil, such as aluminum foil (Al foil).

[0082] The sealing layer may be a layer exposed on the inside of the battery cell. The sealing layer may be a portion that is fusion-bonded by a sealing process, including a melting process, after the electrode assembly is incorporated into the outer material. For example, the sealing layers in the upper and lower pouches may be fused together to form a sealing portion.

[0083] For example, the sealing layers contained in the upper and lower bags can be fused together to form a sealing section. Examples of polyolefin resins can be 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), terpolymers of ethylene-butene-propylene, or the like.

[0084] 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 stacked sequentially from the top of the metal layer.

[0085] The substrate layer may contain a polyester resin, a polyamide resin, an epoxy resin, an acrylic resin, a fluororesin, a polyurethane resin, a silicone resin, a phenolic resin, and mixtures or copolymers thereof.

[0086] Examples of polyester resins may include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, polycarbonate, or the like. Examples of polyamide resins may include nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, and polymethaxylylene adipamide (MXD6).

[0087] For example, the intermediate substrate layer may contain a polyamide resin such as nylon, and the outer substrate layer may contain a polyester resin such as polyethylene terephthalate (PET).

[0088] The layers or films described above can be bonded together, for example, using an adhesive layer. Example

[0089] Hereinafter, embodiments of the present invention will be described in more detail with reference to specific experimental examples. The examples 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. It will be apparent to those skilled in the art that various changes and modifications to the embodiments are possible within the scope and technical idea of ​​the present invention, and it is also understood that such changes and modifications fall within the scope of the appended claims. Examples of productionExamples 1 to 5 and Comparative Examples 1 to 4

[0090] After placing a bag plate having a thickness of 0.15 mm formed of an Al material on a forming support portion and a fixing portion, a stripper was placed on the fixing portion to fix a side portion of the bag plate.

[0091] The pressure of a forming groove was increased to 10 by a vacuum device connected to a vacuum hole located on a lower forming surface. -5 Torr or less, and the forming support portion and a central portion of the bag plate were lowered together toward the lower forming surface.

[0092] By lowering the forming support portion and simultaneously lowering a punch portion while keeping a distance between the forming support portion and the punch portion constant by a control unit, and pressing an upper portion of the central portion of the bag plate by the punch portion to form the central portion of the bag plate, a receiving portion is thereby formed.

[0093] In this case, the distance between the descending forming support section and the punch section was kept constant at the distance shown in Table 1 below.

[00106] [Table 1] Distance between the forming support section and the punch section (mm) Example 1 0,15 Example 2 0,3 Example 3 0,5 Example 4 0,7 Example 5 1 Comparison example 1 5 Comparison example 2 7 Comparison example 3 10 Comparison example 4 15

[00107] Evaluation example

[0094] The degree of expansion of the bag in Examples 1 to 5 and Comparative Examples 1 to 4 was confirmed by measuring the height difference between a corner of a bag receiving portion and a central portion of the bag receiving portion, which is shown in Table 2 below.

[0095] Meanwhile, the phenomenon of bulging of the bag of Example 1 and Comparative Example 1 was photographed, which was Fig. 9 is shown.

[00110] [Table 2] Bag expansion (mm) Example 1 (REF.) 1,2 Example 2 1,3 Example 3 1,5 Example 4 1,6 Example 5 1,9 Comparison example 1 2,3 Comparison example 2 2, 9 Comparison example 3 3,5 Comparison example 4 5,1

[0096] From Table 2, it is clear that Examples 1 to 5 in which the distance between a forming support portion and a punch portion is 1 mm or less have a small expansion of the bag, thereby reducing the phenomenon of bag bulging.

[0097] On the other hand, in Comparative Examples 1 to 4 in which the distance between the forming support portion and the punch portion is more than 1 mm, the degree of expansion of the bag is high, and it can be confirmed that the bulging phenomenon of the bag occurs.

[0098] Based on Fig. 9, it can be visually confirmed that in Comparative Example 1 in which the distance between the molding support portion and the punch portion is relatively large, a bulging phenomenon occurs compared to Example 1.

[0099] The above description is merely an example of the application of the principles of the present invention, and other configurations may be incorporated without departing from the scope of the present invention.

[0100] As set forth above, according to an embodiment of the present invention, a bag formed according to a bag forming apparatus and a bag forming system can prevent cracks in a corner portion of the bag.

[0101] A bag formed by a bag forming apparatus and a bag forming system can suppress an expansion phenomenon of a main body part of the bag.

[0102] Only specific examples of implementations of certain embodiments are described herein. Variations, improvements, and extensions of the disclosed embodiments and other embodiments may be made based on the invention of this description.

Claims

[1] Bag forming system comprising: A molded bag plate obtained in an arranging process of arranging a bag plate between a die portion having a lower molding surface on which a bag plate is molded and a molding support portion disposed on the lower molding surface, and a punch portion for molding the bag plate; and in a first forming process of evacuating an interior space of the die portion and lowering the forming support portion in a direction of the lower forming surface to bend the bag plate; and a second forming process of lowering the punch portion in a direction of the lower forming surface to press the bag plate. [2] The bag forming system according to claim 1, wherein the bag sheet is obtained by performing the first forming process and the second forming process simultaneously. [3] The bag forming system according to claim 1, wherein the bag sheet is obtained by performing the second forming process after performing the first forming process. [4] The bag forming system according to claim 2, wherein the bag plate is obtained by lowering at least one of the forming support portion and the punch portion at a constant speed. [5] The bag forming system according to claim 2, wherein the bag plate is obtained by lowering the punch portion at a speed higher than the lowering speed of the forming support portion. [6] The bag forming system according to claim 3, wherein the bag plate is obtained by lowering the punch portion after completion of lowering the forming support portion. [7] A bag forming system according to claim 3, wherein the bag plate is obtained by lowering and then raising the forming support portion, thereby lowering the punch portion. [8] The bag forming system according to claim 1, wherein the bag plate is obtained by maintaining a distance between the forming support portion and the punch portion at 1 mm or less. [9] The bag forming system of claim 1, further comprising: A control unit for a speed control operation of controlling the moving speed of at least one of the forming support section and the punch section. [10] The bag forming system according to claim 1, wherein the bag plate bent in the first forming process is bent to be convex downward. [11] A bag forming system according to claim 1, comprising a receiving portion formed in the bag plate to have the same shape as an outer shape of the punch portion in the second forming process in which an electrode assembly is received. [12] A lithium secondary battery comprising a bag formed by the bag forming system according to claim 1. [13] Bag forming device comprising: a die section with a forming groove; a punch portion disposed so as to oppose the forming groove and provided so as to move relative to the forming groove; a forming support portion provided to move relative to the punch portion within the forming groove; and a control unit for controlling the moving speed of at least one of the forming support section and the punch section. [14] The bag forming apparatus according to claim 13, wherein the die portion further includes an inner space formed by the forming groove and the forming support portion, and a vacuum device for generating a negative pressure in the inner space. [15] A bag forming apparatus according to claim 13, wherein the die portion further includes a fixing portion on which a bag plate is disposed. [16] A bag forming apparatus according to claim 15, further comprising: a stripper arranged to be spaced from the fixing portion and fixing the bag plate.

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