Molding device and molding method, and pouch-shaped battery case molded thereby

Abstract

A forming device according to an embodiment of the present invention can form a pouch film. The forming device may include a die having a first opening, a stripper that fixes the pouch film above the die and has a second opening, a sub-die whose height relative to the die is variable within the first opening, a punch that presses the pouch film through the second opening and faces the sub-die, and a sub-punch that presses the pouch film between the inner periphery of the first opening and the outer periphery of the sub-die through a gap between the inner periphery of the second opening and the outer periphery of the punch.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0136748, filed October 21, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a molding device and molding method for molding a pouch film, and to a pouch-type battery case molded thereby. [Background technology]

[0003] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, etc. These secondary batteries are used not only in small products such as digital cameras, DVD players, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also in large products that require high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power and new renewable energy.

[0004] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to form a positive electrode and a negative electrode, which are then stacked on both sides of a separator to form an electrode assembly of a predetermined shape, and then the electrode assembly is placed in a battery case, an electrolyte is injected, and the battery case is sealed.

[0005] Secondary batteries are classified into pouch types and can types depending on the material of the case that houses the electrode assembly. Pouch types house the electrode assembly in a pouch made of flexible polymer material, while can types house the electrode assembly in a case made of metal or plastic.

[0006] Generally, a pouch-type battery case is manufactured by pressing a flexible pouch film to form a cup portion, and then, after the cup portion is formed, an electrode assembly is placed inside the cup portion and the sides are sealed to manufacture a secondary battery.

[0007] Generally, in such press working, drawing is performed by inserting a pouch film between a die and a stripper, and applying pressure to the pouch film with a punch to stretch the pouch film.

[0008] However, in such a conventional method, if the cup portion is formed too deep, cracks may occur in the pouch film, and there is a limit to how deep the cup portion can be increased. Summary of the Invention [Problem to be solved by the invention]

[0009] One problem to be solved by the present invention is to provide a molding device and a molding method that can form a deep cup portion in a pouch film by performing the molding process in multiple steps.

[0010] Another object of the present invention is to provide a pouch-shaped battery case manufactured by the molding apparatus or the molding method. [Means for solving the problem]

[0011] A forming device according to an embodiment of the present invention can form a pouch film. The forming device may include a die having a first opening, a stripper that fixes the pouch film above the die and has a second opening, a sub-die whose height relative to the die is variable within the first opening, a punch that presses the pouch film through the second opening and faces the sub-die, and a sub-punch that presses the pouch film between the inner periphery of the first opening and the outer periphery of the sub-die through a gap between the inner periphery of the second opening and the outer periphery of the punch.

[0012] The sub-punch may apply a first pressure to the pouch film with the upper surface of the sub-die and the upper surface of the die positioned on the same plane, and the punch and the sub-punch may apply a second pressure to the pouch film with the upper surface of the sub-die positioned below the upper surface of the die.

[0013] The sub-punch may be arranged to surround the outer periphery of the punch.

[0014] The die may be formed with a protruding step portion that protrudes from the inner periphery of the first opening toward the outer periphery of the sub-die and overlaps with the sub-punch in the vertical direction.

[0015] A forming method according to an embodiment of the present invention can form a pouch film. The forming method may include a fixing step of fixing the pouch film between a die having a first opening and a stripper having a second opening, a primary pressurizing step of using a sub-punch to primarily pressurize the pouch film between an outer periphery of a sub-die located inside the first opening and an inner periphery of the first opening through the second opening, and a secondary pressurizing step of using a punch facing the sub-die via the pouch film to secondarily pressurize the pouch film into the first opening together with the sub-punch through the second opening.

[0016] In the fixing step and / or the first pressing step, the upper surface of the sub-die may be located on the same plane as the upper surface of the die.

[0017] In the fixing step and / or the first pressurizing step, the pouch film may be fixed between the sub-die and the punch.

[0018] In the second pressurizing step, a bottom surface of the punch may be located on the same plane as a bottom surface of the sub-punch.

[0019] In the first pressurizing step, the sub-punch may form a recessed portion having a first depth in the pouch film, and in the second pressurizing step, the punch and the sub-punch may form a cup portion in the pouch film having a second depth deeper than the first depth.

[0020] In the second pressurizing step, the depression may be widened to form the cup portion.

[0021] The die may have a protruding step that protrudes from an inner periphery of the first opening toward an outer periphery of the sub-die. In the second pressurizing step, the sub-punch may press the pouch film to a depth where the pouch film contacts the protruding step.

[0022] In the second pressurizing step, an upper surface of the sub-die may be positioned on the same plane as an upper surface of the protruding step portion.

[0023] A pouch-type battery case according to an embodiment of the present invention may include a cup portion having a recessed shape and a terrace located on a periphery of the cup portion. The periphery of the cup portion may include a first periphery connected to the terrace by a die edge, and a second periphery connected to the first periphery and having a thickness thinner than the first periphery.

[0024] The base of the cup portion may include a first base portion located at the center and a second base portion having a thickness thinner than that of the first base portion and connected to the periphery of the cup portion by a punch edge.

[0025] The thickness of the second peripheral portion may be less than the thickness of the second base portion.

[0026] The thickness of the first peripheral portion may be less than the thickness of the first base portion.

[0027] The thickness of a punch edge connecting the second peripheral portion and the second base portion may be the same as the thickness of the second base portion or the thickness of the second peripheral portion.

[0028] The thickness of a punch edge connecting the second peripheral portion and the second base portion may be the same as the thickness of the second peripheral portion and thinner than the thickness of the second base portion.

[0029] The thickness of a punch edge connecting the second peripheral portion and the second base portion may be the same as the thickness of the second base portion and may be thicker than the thickness of the second peripheral portion.

[0030] The periphery of the cup portion may further include a third periphery connected to the second periphery and having a thickness greater than that of the second periphery. A punch edge connecting the third periphery and the second base portion may have a thickness equal to that of the third periphery and the second base portion and greater than that of the second periphery. [Effects of the Invention]

[0031] According to a preferred embodiment of the present invention, a deep cup portion can be formed without causing cracks in the pouch film. More specifically, in conventional methods, a cup portion is formed by a single pressurization, which results in excessive stretching of only specific regions of the pouch film, and therefore the depth of the cup portion has been limited to prevent cracks from occurring. In contrast, the present invention has the advantage that the forming process is performed multiple times so that regions of the pouch film that were not previously stretched are also stretched, thereby ultimately allowing for a deeper cup portion to be formed.

[0032] Other effects may be included that can be easily predicted by a person skilled in the art from the configuration according to the preferred embodiment of the present invention. [Brief explanation of the drawings]

[0033] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited solely to the matters depicted in such drawings. [Figure 1] 1 is a schematic diagram of a molding apparatus according to one embodiment of the present invention. [Figure 2] 3A to 3C are schematic diagrams sequentially illustrating the operation of a molding device according to an embodiment of the present invention. [Figure 3] 3A to 3C are schematic diagrams sequentially illustrating the operation of a molding device according to an embodiment of the present invention. [Figure 4] 3A to 3C are schematic diagrams sequentially illustrating the operation of a molding device according to an embodiment of the present invention. [Figure 5] 3A to 3C are schematic diagrams sequentially illustrating the operation of a molding device according to an embodiment of the present invention. [Figure 6] 4 is a flowchart of a molding method according to another embodiment of the present invention. [Figure 7] 10A to 10C are schematic views illustrating a manufacturing process of a pouch-type battery case according to still another embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view of a pouch-type battery case according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily understand the preferred embodiments of the present invention. However, the present invention can be realized in various different forms and is not limited to the following embodiments.

[0035] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and when assigning reference symbols to components in each drawing in this specification, the same or similar reference symbols will be assigned to the same or similar components throughout the specification.

[0036] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0037] FIG. 1 is a schematic diagram of a molding apparatus according to one embodiment of the present invention, and FIGS. 2 to 5 are schematic diagrams sequentially showing the operation of a molding apparatus according to one embodiment of the present invention.

[0038] The forming device according to one embodiment of the present invention can form a pouch film 100. The pouch film 100 may have a predetermined thickness. The pouch film 100 may be a formable laminate sheet. More specifically, the pouch film 100 may be a laminate sheet in which a pair of resin layers located on both outermost sides and a metal layer located between the pair of resin layers are laminated.

[0039] A molding apparatus according to one embodiment of the present invention may include a die 10 , a stripper 20 , a sub-die 30 , a punch 40 and a sub-punch 50 .

[0040] Some of the die 10, stripper 20, sub-die 30, punch 40, and sub-punch 50 may be configured to be able to move up and down relative to the others. As one example, any one of the die 10, stripper 20, sub-die 30, punch 40, and sub-punch 50 may be fixed, and the others may be configured to be able to move up and down independently relative to the any one of the above. As another example, each of the die 10, stripper 20, sub-die 30, punch 40, and sub-punch 50 may be configured to be able to move up and down independently.

[0041] The die 10 may be located below the pouch film 100. A first opening 12 may be formed in the die 10. The first opening 12 may be formed by penetrating from the upper surface of the die 10 downward. The first opening 12 may be a forming space in which the pouch film 100 is depressed and formed. The first opening 12 may also be a space in which a sub-die 30, which will be described later, is disposed.

[0042] The cross section of the first opening 12 may be substantially rectangular, but is not limited to this.

[0043] The die 10 may have a curved edge 11. More specifically, the upper surface of the die 10 and the inner periphery of the first opening 12 may be connected by the curved edge 11. The edge 11 may have a predetermined radius of curvature. By forming the edge 11 in a curved shape, it is possible to prevent the portion of the pouch film 100 that is in close contact with the edge 11 from breaking when the pouch film 100 is stretched into the first opening 12.

[0044] The die 10 may be formed with a protruding step 14 that protrudes inward from the inner periphery of the first opening 12. The protruding step 14 may protrude toward the outer periphery of the sub-die 30.

[0045] The protruding step 14 may overlap the sub-punch 50 (described later) in the vertical direction. Therefore, the protruding step 14 can function as a limiter that restricts the downward movement of the sub-punch 50.

[0046] The protruding step 14 may be formed at a position a predetermined distance below the top surface of the die 10. As shown in FIG. 1, the die 10 may include a lower body, part of the inside of which forms the protruding step 14, and an upper body disposed above the lower body and in contact with the pouch film 100. However, the die is not limited thereto, and the configuration of the die may be changed as needed. For example, the die 10 may be formed as a single unit.

[0047] The stripper 20 may face the die 10 via the pouch film 100. The stripper 20 may fix the pouch film 100 on the upper side of the die 10.

[0048] More specifically, at least one of the die 10 and the stripper 20 may be configured to be movable up and down, and the distance between the die 10 and the stripper 20 may be variable. The pouch film 100 may enter between the die 10 and the stripper 20 when the die 10 and the stripper 20 are separated from each other, and then be fixed between the die 10 and the stripper 20 when the die 10 and the stripper 20 approach each other. That is, the pouch film 100 may be fixed between the top surface of the die 10 and the bottom surface of the stripper 20.

[0049] A second opening 22 may be formed in the stripper 20. The second opening 22 may be formed penetrating upward from the bottom surface of the stripper 20. The second opening 22 may be a space in which a punch 40 and a sub-punch 50, which will be described later, are disposed.

[0050] The cross section of the second opening 22 may be, but is not limited to, a substantially rectangular shape. The second opening 22 may be located above the first opening 12. The second opening 22 and the first opening 12 may face each other with the pouch film 100 interposed therebetween.

[0051] The height of the sub-die 30 relative to the die 10 may be variable within the first opening 12. More specifically, at least one of the die 10 and the sub-die 30 may be configured to be movable up and down, and the height difference between the upper surface of the die 10 and the upper surface of the sub-die 30 may be variable.

[0052] The sub-die 30 may have a curved edge 31. More specifically, the top surface and the outer periphery of the sub-die 30 may be connected by the curved edge 31. The edge 31 may have a predetermined radius of curvature. By forming the edge 31 in a curved shape, it is possible to prevent the portion of the pouch film 100 that is in close contact with the edge 31 from breaking when the pouch film 100 is stretched into the first opening 12.

[0053] 2 and 3, during primary forming when the sub-punch 50 presses the pouch film 100, the sub-die 30 may fix the pouch film 100 together with the punch 40. More specifically, when the sub-punch 50 presses the pouch film 100, the center of the pouch film 100 may be fixed between the bottom surface of the punch 40 and the top surface of the sub-die 30.

[0054] 4 and 5, during secondary forming when the punch 40 and the sub-punch 50 press together the pouch film 100, the upper surface of the sub-die 30 may be located below the upper surface of the die 10. More specifically, when the punch 40 and the sub-punch 50 press together the pouch film 100, the upper surface of the sub-die 30 may be located on the same plane as the upper surface of the protruding step 14. In this case, the sub-die 30 can function as a limiter that restricts the descent of the punch 40.

[0055] The punch 40 may apply pressure to the pouch film 100 through the second opening 22. The height of the punch 40 relative to the sub-die 30 may be variable within the second opening 22. More specifically, at least one of the punch 40 and the sub-die 30 may be configured to be movable up and down, and the height difference between the bottom surface of the punch 40 and the top surface of the sub-die 30 may be variable.

[0056] The punch 40 may have a curved edge 41. More specifically, the outer periphery and bottom surface of the punch 40 may be connected by the curved edge 41. The edge 41 may have a predetermined radius of curvature. By forming the edge 41 in a curved shape, it is possible to prevent the portion that comes into close contact with the edge 41 from breaking when the punch 40 presses the pouch film 100.

[0057] As described above, the punch 40 may fix the pouch film 100 together with the sub-die 30 during the primary molding, and may pressurize the pouch film 100 together with the sub-punch 50 during the secondary molding. More specifically, the punch 40 may be configured to descend toward the sub-die 30 to pressurize the pouch film 100.

[0058] The sub-punch 50 may press the pouch film 100 through the second opening 22. More specifically, the sub-punch 50 may press the pouch film 100 between the inner periphery of the first opening 12 and the outer periphery of the sub-die 30 via the inner periphery of the second opening 22 and the outer periphery of the punch 40.

[0059] The sub-punch 50 may be vertically opposed to the protruding step 14 of the die 10. The sub-punch 50 may be arranged to surround the outer periphery of the punch 40. The sub-punch 50 may be located between the outer periphery of the punch 40 and the inner periphery of the second opening 22. That is, the outer periphery of the sub-punch 50 may be opposed to the inner periphery of the second opening 22, and the inner periphery of the sub-punch 50 may be opposed to the outer periphery of the punch 40.

[0060] The sub-punch 50 may be raised and lowered independently of the punch 40. The height of the sub-punch 50 relative to the die 10 may be variable within the second opening 22. More specifically, at least one of the sub-punch 50 and the die 10 may be configured to be able to be raised and lowered, and the height difference between the bottom surface of the sub-punch 50 and the top surface of the die 10 may be variable.

[0061] The sub-punch 50 may have a curved edge 51. More specifically, the outer and inner peripheries and the bottom surface of the sub-punch 50 may be connected by a curved edge 45. The edge 51 may have a predetermined radius of curvature. Alternatively, the bottom surface of the sub-punch 50 may be curved. This prevents the edge 51 or the portion in close contact with the bottom surface from breaking when the sub-punch 50 presses the pouch film 100.

[0062] During the primary forming, the sub-punch 50 may form the pouch film 100 to a first depth d1. During the secondary forming, the punch 40 and the sub-punch 50 may both form the pouch film 100 to a second depth d2 that is deeper than the first depth d1.

[0063] The operation of the molding apparatus according to one embodiment of the present invention will be described below. For ease of explanation, the following will be described taking as an example a case where the die 10 is fixed and the stripper 20, sub-die 30, punch 40, and sub-punch 50 each move up and down independently.

[0064] 1 , with the pouch film 100 inserted between the die 10 and the stripper 20, the stripper 20 descends toward the die 10, thereby fixing a portion of the outer side of the pouch film 100 between the stripper 20 and the die 10. Furthermore, the punch 40 descends toward the sub-die 30, thereby fixing a portion of the inner side of the pouch film 100 between the punch 40 and the sub-die 30. In this case, the top surface of the die 10 and the top surface of the sub-die 30 may be located on the same horizontal plane, and the bottom surface of the punch 40 and the bottom surface of the stripper 20 may be located on the same horizontal plane. Thus, the pouch film 100 can be fixed so as to maintain its flat state to the maximum extent possible.

[0065] 2, the sub-punch 50 can pressurize the pouch film 100 between the inner periphery of the first opening 12 and the outer periphery of the sub-die 30 via the inner periphery of the second opening 22 and the outer periphery of the punch 40. This type of pressure molding is called primary molding, and this primary molding can form a depression 110 in the pouch film 100. The depression 110 may have a first depth d1.

[0066] 3, the sub-die 30 can be lowered. This allows the portion of the pouch film 100 that was fixed between the sub-die 30 and the punch 40 to be released. More specifically, the sub-die 30 can be lowered so that its upper surface is positioned on the same horizontal plane as the upper surface of the protruding step portion 14. Furthermore, the sub-punch 50 can be raised. More specifically, the sub-punch 50 can be raised so that its bottom surface is positioned on the same horizontal plane as the bottom surface of the punch 40.

[0067] 4, the punch 40 and the sub-punch 50 can both descend to pressurize the pouch film 100. At this time, the sub-punch 50 can pressurize the pouch film 100 to a depth where the pouch film 100 contacts the protruding step portion 14, and the punch 40 can pressurize the pouch film 100 to a depth where the pouch film 100 contacts the sub-die 30.

[0068] This type of pressure molding is called secondary molding, and the secondary molding expands the depression 110 already formed in the pouch film 100, thereby forming the cup portion 120. The cup portion 120 may have a second depth d2 that is deeper than the first depth d1 of the depression 110.

[0069] 5, the punch 40 and the sub-punch 50 can be raised and returned to their initial positions. Although not shown, the stripper 20 also rises, thereby releasing the pouch film 100 that has been fixed between the die 10 and the stripper 20.

[0070] Through this series of processes, the formation of the cup portion 120 in the pouch film 100 can be completed. Conventionally, the cup portion was formed by a single pressurization, but in that case, only a specific region of the pouch film was excessively stretched, and the depth of the cup portion was limited to prevent cracks from occurring. In contrast, the present invention has the advantage that the formation is performed multiple times so that regions of the pouch film 100 that were not previously stretched are also stretched, thereby ultimately forming the cup portion 120 deeper.

[0071] FIG. 6 is a flowchart of a molding method according to another embodiment of the present invention.

[0072] Hereinafter, as another embodiment of the present invention, a molding method for molding the pouch film 100 using the above-mentioned molding device will be described.

[0073] A molding method according to another embodiment of the present invention may include a fixing step (S10) (hereinafter referred to as the "fixing step") of fixing the pouch film 100 between the die 10 and the stripper 20, a primary pressure step (S20) (hereinafter referred to as the "primary molding step") of using the sub-punch 50 to apply primary pressure to the pouch film 100 between the outer periphery of the sub-die 30 and the inner periphery of the first opening 12, and a secondary pressure step (S30) (hereinafter referred to as the "secondary pressure step") of using the punch 40 to apply secondary pressure to the pouch film 100 together with the sub-punch 50.

[0074] The above-described explanation of the operation of the molding apparatus can be applied to each of steps S10, S20, and S30. More specifically, the fixing step (S10) can be applied to the content explained with reference to Fig. 1, the primary molding step (S20) can be applied to the content explained with reference to Figs. 2 and 3, and the secondary pressurizing step (S30) can be applied to the content explained with reference to Figs. 4 and 5. The main features will be briefly described below.

[0075] In the fixing step (S10) and / or the primary forming step (S20), the upper surface of the sub-die 30 may be located on the same plane as the upper surface of the die 10. In the fixing step (S10) and / or the primary forming step (S20), the pouch film 100 may be fixed between the sub-die 30 and the punch 40.

[0076] In the primary forming step (S20), the sub-punch 50 may form a depression 110 having a first depth d1 in the pouch film 100.

[0077] In the secondary forming step (S30), the punch 40 and the sub-punch 50 may form a cup portion 120 having a second depth d2 deeper than the first depth d1 in the pouch film 100. In the secondary pressurizing step (S30), the recessed portion 110 may be widened to form the cup portion 120. In the secondary pressurizing step (S30), the sub-punch 50 may press the pouch film 100 to a depth at which the pouch film 100 contacts the protruding step 14.

[0078] In the secondary pressurizing step (S30), the bottom surface of the punch 40 may be located on the same plane as the bottom surface of the sub-punch 50. In the secondary pressurizing step (S30), the top surface of the sub-die 30 may be located on the same plane as the top surface of the protruding step portion 14.

[0079] Fig. 7 is a schematic diagram illustrating a manufacturing process of a pouch-type battery case according to another embodiment of the present invention, and Fig. 8 is a cross-sectional view of the pouch-type battery case according to another embodiment of the present invention. In Fig. 7, the solid line indicates the recessed portion 110, and the dotted line indicates the cup portion 120.

[0080] Hereinafter, as still another embodiment of the present invention, a pouch-type battery case manufactured by the above-described molding device or molding method will be described.

[0081] A pouch-type battery case (hereinafter, referred to as a “battery case”) according to yet another embodiment of the present invention may include a cup portion 120 having a recessed shape and a terrace 130 located on the periphery of the cup portion 120 .

[0082] The cup portion 120 may form a space for accommodating an electrode assembly (not shown). The terrace 130 may be a portion of the pouch film 100 that is fixed between the die 10 and the stripper 20 and does not have the cup portion 120.

[0083] In the manufacturing process of the battery case, the recess 110 may be formed first, and then the recess 110 may be expanded to form the cup portion 120 having a depth greater than that of the recess 110 secondarily.

[0084] The recess 110 may include an outer periphery 112 , an inner periphery 113 , and a connecting portion 114 .

[0085] The outer periphery 112 may be connected to the terrace 130 by a die edge 111. The die edge 111 may be formed in a curved shape. More specifically, the die edge 111 may have a predetermined radius of curvature. The die edge 111 may be formed by the edge 11 of the die 10 (see FIG. 1 ) and may have a radius of curvature corresponding to the edge 11 of the die 10.

[0086] The inner peripheral portion 113 may be connected to the central portion 101 by a connecting edge 115. The central portion 101 may be a portion that is fixed between the punch 40 and the sub-die 30 during the primary molding of the pouch film 100 and does not have the recessed portion 110 formed therein. The connecting edge 115 may be formed in a curved shape. More specifically, the connecting edge 115 may have a predetermined radius of curvature. The connecting edge 115 may be formed by the edge 31 of the sub-die 30 (see FIG. 1 ), and may have a radius of curvature corresponding to the edge 31 of the sub-die 30.

[0087] The connecting portion 114 may connect the outer circumferential portion 112 and the inner circumferential portion 113. The connecting portion 114 may have a shape corresponding to the bottom surface of the sub-punch 50.

[0088] During the primary molding of the pouch film 100, the terraces 130 and the central portion 101 are not stretched, so that the remaining thickness is large and may be the same as the thickness of the pouch film 100.

[0089] The connecting portion 114 may have a smaller remaining thickness due to being directly pressed by the sub-punch 50 and being stretched relatively more. In addition, the outer peripheral portion 112 and the inner peripheral portion 113 may be stretched relatively less than the connecting portion 114. The die edge 111 and the connecting edge 115 may also be stretched to the same extent as or to the same extent as the outer peripheral portion 112 and the inner peripheral portion 113.

[0090] Therefore, the thickness of each of the outer circumferential portion 112 , inner circumferential portion 113 , die edge 111 and connecting edge 115 may be thicker than the thickness of the connecting portion 114 and thinner than the thickness of the terrace 130 and central portion 101 .

[0091] During secondary molding of the pouch film 100, the outer circumferential portion 112 of the depression 110 may form a first circumferential portion 122a, which is a part of the peripheral portion 122 of the cup portion 120. In addition, the connecting portion 114, the inner circumferential portion 113, the connecting edge 115, and the central portion 101 of the depression 110 may form a second circumferential portion 122b, which is another part of the peripheral portion 122 of the cup portion 120, the base portion 121, and the punch edge 123.

[0092] Therefore, taking the cross-sectional view of Figure 7 as a reference, if in the recessed portion 110, the length of the connecting portion 114 is L1, the length of the inner peripheral portion 113 is L2, the length of the connecting edge 115 is L3, and the length of the central portion 101 is L4, and in the cup portion 120, the length of the second peripheral portion 122b is L5, the length of the punch edge 123 is L6, and the length of the base portion 121 is L7, then the conditional expression 2*(L1+L2+L3)+L2=2*(L5+L7)+L6 may be satisfied.

[0093] The length L1 of the connecting portion 114 may refer to the length from a boundary P1 between the outer circumferential portion 112 and the connecting portion 114 to a boundary P2 between the connecting portion 114 and the inner circumferential portion 113. The length L2 of the inner circumferential portion 113 may refer to the length from the boundary P2 between the connecting portion 114 and the inner circumferential portion 113 to a boundary P3 between the inner circumferential portion 113 and the connecting edge 115. The length L3 of the connecting edge 115 may refer to the length from the boundary P3 between the inner circumferential portion 113 and the connecting edge 115 to a boundary P4 between the connecting edge 115 and the central portion 101. The length L4 of the central portion 101 may refer to the length between one boundary P4 between the connecting edge 115 and the central portion 101 and the other boundary P4. The length L5 of the second circumferential portion 122b may refer to the distance from the boundary P1 between the outer circumferential portion 112 and the connecting portion 114 to a boundary P5 between the second circumferential portion 122b and the punch edge 123. The length L6 of the punch edge 123 can mean the distance from the boundary P5 between the second peripheral portion 122b and the punch edge 123 to the boundary P6 between the punch edge 123 and the base portion 121. The length L7 of the base portion 121 can mean the length between one boundary P6 between the punch edge 123 and the base portion 121 and the other boundary P6.

[0094] The recess 110 is expanded to form the cup portion 120, so the thickness of each portion of the cup portion 120 differs from that of a cup portion formed in a conventional manner. Hereinafter, the cup portion 120 will be described with reference to both FIGS. 7 and 8.

[0095] The cup portion 120 may include a base portion 121 and a perimeter portion 122 .

[0096] The periphery 122 of the cup portion 120 may be connected to the terrace 130 by a die edge 111. The die edge 111 may be maintained in a state formed when the preceding recessed portion 110 was molded.

[0097] The base portion 121 of the cup portion 120 may be connected to the peripheral portion 122 by a punch edge 123. The punch edge 123 may be formed in a curved shape. More specifically, the punch edge 123 may have a predetermined radius of curvature. The punch edge 123 may be formed by the edge 51 of the sub-punch 50 (see FIG. 1 ), and may have a radius of curvature corresponding to the edge 51 of the sub-punch 50.

[0098] The peripheral portion 122 of the cup portion 120 may include a first peripheral portion 122a connected to the terrace 130 by the die edge 111, and a second peripheral portion 122b connected to the base portion 121 by the punch edge 123 and having a thickness thinner than the first peripheral portion 122a.

[0099] The first circumferential portion 122a may correspond to the outer circumferential portion 112 of the recessed portion 110, and the second circumferential portion 122b may correspond to the connecting portion 114 of the recessed portion 110. That is, the outer circumferential portion 112 may form the first circumferential portion 122a, and the connecting portion 114 may be expanded to form the second circumferential portion 122b. As described above, the remaining thickness of the connecting portion 114 may be thinner than the remaining thickness of the outer circumferential portion 112, and therefore the thickness t2 of the second circumferential portion 122b may be relatively thinner than the thickness of the first circumferential portion 122a.

[0100] The base portion 121 of the cup portion 120 may include a first base portion 121a located in the center and a second base portion 121b having a thickness thinner than that of the first base portion 121a and connected to the periphery portion 122 by a punch edge 123.

[0101] The first base portion 121a may correspond to the central portion 101, and the second base portion 121b may correspond to the inner periphery 113 and connecting edge 115 of the recessed portion 110. That is, the central portion 101 may form the first base portion 121a, and the inner periphery 113 and connecting edge 115 may be widened to form the second base portion 121b. As described above, the remaining thickness of the inner periphery 113 and connecting edge 115 may be thinner than the remaining thickness of the central portion 101, and therefore the thickness t4 of the second base portion 121b may be relatively thinner than the thickness of the first base portion 121a.

[0102] Furthermore, the thickness t2 of the second peripheral portion 122b may be thinner than the thickness of the second base portion 121b because, as described above, the remaining thickness of the connecting portion 114 is thinner than the remaining thickness of the inner peripheral portion 113 and the connecting edge 115.

[0103] Furthermore, the thickness t1 of the first peripheral portion 122a may be thinner than the thickness t3 of the first base portion 121a because, as described above, the remaining thickness of the outer peripheral portion 112 is thinner than the remaining thickness of the central portion 101.

[0104] Meanwhile, the thickness of the punch edge 123 varies depending on the ratio of the lengths of the connecting portion 114 and the inner circumferential portion 113. This is because the connecting portion 114 or the inner circumferential portion 113 forms the punch edge 123, and as described above, the remaining thickness of the connecting portion 114 is thinner than the remaining thickness of the inner circumferential portion 113.

[0105] As a first example, if the connecting portion 114 is sufficiently long, the connecting portion 114 can be widened to form not only the second periphery 122b but also the punch edge 123, and the inner periphery 113 can be widened to form the second base portion 121b. In this case, the thickness of the punch edge 123 is the same as the thickness t2 of the second periphery 122b but is thinner than the thickness t4 of the second base portion 121b. In addition, the punch edge 123 can connect the second periphery 122b and the second base portion 121b.

[0106] As a second example, when the connecting portion 114 is shorter than the first example, the connecting portion 114 can be widened to form the second periphery 122b, and the inner periphery 113 can be widened to form the punch edge 123 and the second base portion 121b. In this case, the thickness of the punch edge 123 is the same as the thickness t4 of the second base portion 121b and is thicker than the thickness t2 of the second periphery 122b. In addition, the punch edge 123 can connect the second periphery 122b and the second base portion 121b.

[0107] As a third example, when the connecting portion 114 is shorter than the second example, the connecting portion 114 may be widened to form the second periphery 122b, and the inner periphery 113 may be widened to form the third periphery, the punch edge 123, and the second base portion 121b. The third periphery is the portion between the second periphery 122b and the punch edge 123. That is, the periphery 122 of the cup portion 120 further includes a third periphery that is connected to the second periphery 122b and has a thickness greater than that of the second periphery 122b.

[0108] In this case, the thickness of the punch edge 123 may be the same as the thickness t4 of the third periphery and the second base portion 121b, and may be thicker than the thickness t2 of the second periphery 122b. Also, the punch edge 123 may connect the third periphery and the second base portion 121b.

[0109] To summarize the first to third examples, the thickness of the punch edge 123 may be the same as the thickness t2 of the second peripheral portion 122b or the thickness t4 of the second base portion 121b. Also, the thickness of the punch edge 123 may be thinner than the thickness t4 of the second base portion 121b or thicker than the thickness t2 of the second peripheral portion 122b.

[0110] The above description merely exemplifies the technical concept of the present invention, and various modifications and variations may be made by a person having ordinary knowledge in the technical field to which the present invention pertains without departing from the essential characteristics of the present invention.

[0111] Therefore, the embodiments disclosed in the present invention are for illustrative purposes only and are not intended to limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0112] The scope of protection of the present invention should be interpreted by the appended claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0113] 10 Die 12 First opening 14 Protruding step 20 Stripper 22 Second opening 30 Subdie 40 Punch 50 Sub-punch 100 pouch film 101 Central part 110 Depression 111 Die Edge 112 Outer periphery 113 Inner circumference 114 Connecting part 115 Connected Edges 120 Cup section 121 Base 121a 1st base 121b 2nd base 122 Periphery 122a 1st lap 122b 2nd circumference 130 Terrace

Claims

1. In a forming apparatus for forming a pouch film, a die having a first opening formed therein; a stripper that secures the pouch film above the die, the stripper having a second opening; a sub-die whose height is variable relative to the die within the first opening; a punch that presses the pouch film through the second opening, the punch facing the sub-die; a sub-punch that presses the pouch film between the inner periphery of the first opening and the outer periphery of the sub-die through the gap between the inner periphery of the second opening and the outer periphery of the punch, forming a molding device.

2. The sub-punch applies a first pressure to the pouch film in a state where an upper surface of the sub-die and an upper surface of the die are positioned on the same plane, The molding device according to claim 1 , wherein the punch and the sub-punch apply secondary pressure to the pouch film in a state where an upper surface of the sub-die is positioned below an upper surface of the die.

3. The forming apparatus according to claim 1 , wherein the sub-punch is disposed so as to surround the outer periphery of the punch.

4. The molding device according to any one of claims 1 to 3, wherein the die has a protruding step portion that protrudes from the inner periphery of the first opening toward the outer periphery of the sub-die and vertically overlaps with the sub-punch.

5. A molding method for forming a pouch film, a fixing step of fixing the pouch film between a die having a first opening and a stripper having a second opening; a primary pressurizing step in which a sub-punch primarily pressurizes the pouch film between an outer periphery of a sub-die located inside the first opening and an inner periphery of the first opening through the second opening; a secondary pressurizing step in which a punch facing the sub-die through the pouch film, together with the sub-punch, secondarily pressurizes the pouch film into the inside of the first opening through the second opening.

6. The molding method according to claim 5 , wherein in the fixing step and / or the primary pressure step, an upper surface of the sub-die is positioned on the same plane as an upper surface of the die.

7. The molding method according to claim 5 , wherein in the fixing step and / or the primary pressurizing step, the pouch film is fixed between the sub-die and the punch.

8. The molding method according to claim 5 , wherein in the secondary pressurizing step, the bottom surface of the punch is positioned on the same plane as the bottom surface of the sub-punch.

9. In the first pressurizing step, the sub-punch forms a depression having a first depth in the pouch film, The molding method according to claim 5 , wherein in the second pressurizing step, the punch and the sub-punch form a cup portion in the pouch film having a second depth deeper than the first depth.

10. The molding method according to claim 9 , wherein the recessed portion is widened to form the cup portion in the second pressurizing step.

11. The die is formed with a protruding step portion that protrudes from the inner periphery of the first opening toward the outer periphery of the sub-die, The molding method according to any one of claims 5 to 10, wherein in the secondary pressurizing step, the sub-punch presses the pouch film to a depth at which the pouch film contacts the protruding step portion.

12. The molding method according to claim 11 , wherein in the secondary pressurizing step, an upper surface of the sub-die is positioned on the same plane as an upper surface of the protruding step portion.

13. a cup portion having a recessed shape; a terrace located on the periphery of the cup portion, The periphery of the cup portion is a first circumferential portion connected to the terrace by a die edge; The pouch-type battery case includes a second periphery connected to the first periphery and having a thickness thinner than that of the first periphery.

14. The base of the cup portion is a centrally located first base portion; The pouch-type battery case according to claim 13 , further comprising a second base portion having a thickness thinner than that of the first base portion, the second base portion being connected to the periphery of the cup portion by a punch edge.

15. The pouch-type battery case according to claim 14 , wherein the thickness of the second peripheral portion is thinner than the thickness of the second base portion.

16. The pouch-type battery case according to claim 14 , wherein the thickness of the first peripheral portion is thinner than the thickness of the first base portion.

17. The thickness of the punch edge connecting the second peripheral portion and the second base portion is The pouch-type battery case according to claim 14 , wherein the thickness of the second base portion is the same as the thickness of the second peripheral portion.

18. The thickness of the punch edge connecting the second peripheral portion and the second base portion is The pouch-type battery case according to claim 14 , wherein the thickness of the second peripheral portion is the same as that of the second base portion and is thinner than that of the second base portion.

19. The thickness of the punch edge connecting the second peripheral portion and the second base portion is The pouch-type battery case according to claim 14 , wherein the thickness of the second base portion is the same as that of the second peripheral portion and is thicker than that of the second peripheral portion.

20. The periphery of the cup portion is The third circumferential portion is connected to the second circumferential portion and has a thickness greater than that of the second circumferential portion. The thickness of the punch edge connecting the third peripheral portion and the second base portion is The pouch-type battery case according to claim 14 , wherein the thickness of the third periphery and the second base portion is the same, and the thickness of the second periphery is greater than the thickness of the second periphery.

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