Pouch forming equipment

Abstract

A pouch forming apparatus related to one embodiment of the present invention is for forming a cup portion in a preforming region of a pouch sheet, and includes a first die unit having a mold opening and configured to seat the pouch sheet so that the preforming region covers the mold opening, a first pressure unit for fixing the pouch sheet to the first die unit, and a stretching unit including a first stretching member configured to pressurize a central region of the preforming region of the pouch sheet and a second stretching member configured to pressurize a first edge region surrounding the central region, and the first and second stretching members may be configured to pressurize the central region and the first edge region, respectively, along different directions toward the mold opening.

Description

[Technical Field]

[0001] The present invention relates to a pouch forming apparatus, and more particularly to a pouch forming apparatus that can primarily stretch a preforming region of a pouch sheet and then secondarily stretch the primarily stretched preforming region to form a cup portion.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0167445, filed November 28, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference. [Background technology]

[0003] FIG. 1 is a diagram showing the configuration of a conventional pouch forming apparatus, FIG. 2(a) is a perspective view of a pouch having a cup portion formed by the conventional pouch forming apparatus, and FIG. 2(b) is a cross-sectional view taken along line XX of FIG. 2(a).

[0004] The pouch forming device (10) includes a die section (20) provided with a die groove (22), a punching block (30) provided so as to be insertable into the die groove (22), and a stripper (40) for fixing the pouch sheet (1) to the die upper surface (21) of the die section (20).

[0005] When forming a pouch having the cup portion 2, the pouch sheet 1 is placed on the die upper surface 21 so as to cover the mold groove 22. The pouch sheet 1 is fixed to the die portion 20 by a stripper 40.

[0006] Next, the punching block (30) moves in a direction (F2) approaching the mold groove (22) to stretch the central portion of the pouch sheet (1) into the mold groove (22), thereby forming a cup portion (2) in the pouch sheet (1). The punching block (30) is used to form the cup portion (2) and can have a roughly rectangular parallelepiped block shape.

[0007] In the manufacturing process of the battery cell, the cup portion (2) of the pouch is a portion in which an electrode assembly (not shown) is housed. The electrode assembly (not shown) is formed by stacking a positive electrode and a negative electrode in order with a separator between them.

[0008] According to the product specifications, the thicker the electrode assembly (not shown), the deeper the molding depth (D) of the cup portion 2. In addition, in a pouch provided with one cup portion 2, the molding depth (D) of the cup portion 2 must be set to a depth that can accommodate the electrode assembly (not shown).

[0009] When the pouch sheet 1 is stretched by the punching block 30, stress is concentrated at the block corners 34 and 35 of the punching block 30. As shown in Figure 2, the cup corners 4 and 5 of the cup part 2, which are in contact with the block corners 34 and 35 of the punching block 30, may be stretched more than the cup bottom 3. As a result, the cup corners 4 and 5 may be stretched to a thickness thinner than the thickness of the cup bottom 3.

[0010] The deeper the forming depth (D) of the cup part 2, the thinner the thickness of the cup corner parts 4, 5. Also, the cup corner parts 4, 5 may be elongated to a thickness thinner than the thickness of the cup bottom surface 3, which may cause cracks.

[0011] The molding depth (D) of the cup portion (2) can be a factor that limits the product specifications of the battery cell, so a pouch molding device (10) that can mold the cup portion (2) to a molding depth (D) that corresponds to the product specifications is required. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a pouch forming device that can primarily stretch a preforming region of a pouch sheet and then secondarily stretch the primarily stretched preforming region to form a cup portion. [Means for solving the problem]

[0013] A pouch forming apparatus related to one embodiment of the present invention is for forming a cup portion in a preforming region of a pouch sheet, and includes a first die unit having a mold opening and configured to seat the pouch sheet so that the preforming region covers the mold opening, a first pressure unit for fixing the pouch sheet to the first die unit, and a stretching unit including a first stretching member configured to pressurize a central region of the preforming region of the pouch sheet and a second stretching member configured to pressurize a first edge region surrounding the central region, and the first and second stretching members may be configured to pressurize the central region and the first edge region, respectively, along different directions toward the mold opening.

[0014] In one embodiment of the present invention, the second extending member may be configured to simultaneously apply pressure to a plurality of first points along the circumferential direction of the first edge region.

[0015] In one embodiment of the present invention, the second extension member may be provided such that a virtual first line connecting the plurality of first points forms a closed curve.

[0016] In one embodiment of the present invention, the second extension member may be provided such that a virtual first line connecting the plurality of first points has a circular shape with a radius larger than that of a central region.

[0017] In one embodiment of the present invention, the second extension member may be provided such that a virtual first line connecting the plurality of first points has a polygonal shape.

[0018] In one embodiment of the present invention, the second extension member may be provided such that the plurality of first points are spaced apart from the central region by a predetermined distance.

[0019] In one embodiment of the present invention, the stretching unit may further include a third stretching member configured to pressurize a second edge region surrounding the first edge region, and the second stretching member and the third stretching member may be configured to pressurize the first edge region and the second edge region, respectively, along different directions toward the mold opening.

[0020] In one embodiment of the present invention, the third extension member may be configured to simultaneously press a plurality of second points along the circumferential direction of the second edge region.

[0021] In one embodiment of the present invention, the third extending member may be provided such that a virtual second line connecting the plurality of second points forms a closed curve.

[0022] In one embodiment of the present invention, the third extension member may be provided such that a virtual second line connecting the plurality of second points has a circular shape having a radius larger than that of the first edge region.

[0023] In one embodiment of the present invention, the third extension member may be provided such that the virtual second line connecting the plurality of second points has a polygonal shape.

[0024] In one embodiment of the present invention, the second and third extending members may be provided such that the first and second imaginary lines have a circular shape.

[0025] In one embodiment of the present invention, the second extending member and the third extending member may be provided such that the first imaginary line and the second imaginary line each have a polygonal shape.

[0026] In an embodiment of the present invention, the pouch forming apparatus may further include a control unit configured to control the movements of the first to third stretching members.

[0027] In one embodiment of the present invention, the control unit may be configured to cause the first and third stretching members to simultaneously pressurize the preforming area.

[0028] In one embodiment of the present invention, the control section can be provided so that the first to third stretching members simultaneously pressurize the preforming region.

[0029] In one embodiment of the present invention, the first to third stretching members may have curved portions in their portions that come into contact with the preforming region.

[0030] In one embodiment of the present invention, the first to third stretching members may have rotatably arranged balls in the portions that come into contact with the preforming region.

[0031] A pouch forming apparatus according to one embodiment of the present invention may further include a second die unit having a mold groove in which the pre-forming region is seated after completion of molding via the extension unit, a second pressure unit for fixing the pouch sheet seated in the second die unit, and a punching block insertable into the mold groove, and may further include a punching unit configured to extend the pre-forming region into the mold groove. [Effects of the Invention]

[0032] As described above, the pouch forming apparatus related to one embodiment of the present invention has the following advantages.

[0033] In conventional pouch forming devices, the punching unit stretches the pouch sheet into the mold groove to form the cup portion, which causes stress to concentrate in the cup corners of the cup portion, which are the areas that are pressed by the block corners of the punching block, resulting in a problem in that the thickness of the cup corners is stretched to be thinner than the thickness of the cup bottom of the cup portion.

[0034] A pouch forming apparatus related to one embodiment of the present invention can form the cup portion by primarily stretching the pre-forming region of the pouch sheet in which the cup portion is to be formed so as to bend the pouch sheet upward and downward, and then secondarily stretching the primarily stretched pouch using a punching block.

[0035] The pouch forming device can prevent stress from concentrating on the block corners by pressurizing the primarily stretched portions of the block corners of the punching blocks.

[0036] This allows the cup portion to be formed with a uniform thickness at the cup bottom and cup corners, eliminating the uneven stretching problem that occurs in the cup corners of the conventional cup portion.

[0037] In addition, when forming the cup, uneven stretching at the cup corners can be eliminated, preventing thickness reduction and cracks at the cup corners.

[0038] In addition, after the pre-molding region of the pouch sheet is primarily stretched to a molding depth according to the final product specifications, the primarily stretched pouch can be stretched into a mold groove having the molding depth to form the cup portion. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a conventional pouch forming device. [Figure 2] 2(a) is a perspective view of a pouch provided with a cup portion formed by a pouch forming apparatus according to the prior art, and FIG. 2(b) is a cross-sectional view taken along line XX of FIG. 2(a). [Figure 3] 1 is a diagram schematically illustrating the configuration of a pouch forming apparatus according to an embodiment of the present invention. [Figure 4] 1 is an example of a pouch sheet having a pre-forming area divided into multiple areas according to an embodiment of the present invention; [Figure 5]1A and 1B are diagrams showing the arrangement of a plurality of stretching members seen from above the first die section according to this embodiment, including (a) an arrangement of a plurality of stretching members having circular ring cross sections, (b) an arrangement of a plurality of stretching members having square ring cross sections, and (c) an arrangement of a plurality of stretching members having polygonal ring cross sections. [Figure 6] 4 is a diagram illustrating an operation state of the extension unit in one embodiment of the present invention. FIG. [Figure 7] 4 is a diagram illustrating an operation state of the extension unit in one embodiment of the present invention. FIG. [Figure 8] 8(a) is a perspective view of a pouch that has been primarily stretched according to an embodiment of the present invention, and FIG. 8(b) is a YY cross-sectional view of FIG. 8(a). [Figure 9] FIG. 10 is a diagram illustrating the process of forming a primarily stretched pouch into a pouch having a cup portion, showing the arrangement of a second die unit, a second pressure unit, and a punching unit. [Figure 10] FIG. 10 is a diagram illustrating the process of forming a primarily stretched pouch into a pouch having a cup portion, showing the operation state of the punching unit in which the punching block of the punching unit is inserted into the mold groove of the second die unit. [Figure 11] 11(a) is a perspective view of a pouch provided with a cup portion according to one embodiment of the present invention, and FIG. 11(b) is a ZZ cross-sectional view of FIG. 11(a). DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, a pouch forming apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0041] Furthermore, regardless of the drawing symbols, identical or corresponding components will be given the same or similar reference numbers, and duplicate descriptions thereof will be omitted. For the sake of convenience, the size and shape of each component illustrated may be exaggerated or reduced.

[0042] FIG. 3 is a diagram illustrating the configuration of a pouch forming apparatus according to one embodiment of the present invention, FIG. 4 is an example diagram illustrating a pouch sheet pre-forming area divided into multiple areas, FIG. 5 is a diagram illustrating the arrangement of multiple stretching members as viewed from above the first die unit according to this embodiment, and FIGS. 6 and 7 are diagrams illustrating the operation of the stretching unit in one embodiment of the present invention.

[0043] A pouch forming apparatus (300) according to one embodiment of the present invention is for forming a cup portion (241) in a preforming area (A) of a pouch sheet (200). The preforming area (A) is a partial area of ​​the pouch sheet (200) that is to be formed into the cup portion (241).

[0044] As shown in FIG. 3, the pouch forming device (300) may include a first die section (310) having a mold opening (312) and configured to seat the pouch sheet (200) so that the pre-forming area (A) covers the mold opening (312).

[0045] The first die portion (310) has a first die upper surface (311) and a mold opening (312). The first die upper surface (311) is where the pouch sheet (200) is placed. The mold opening (312) is an opening that penetrates the first die upper surface (311) along a height direction (H). The height direction (H) is a direction perpendicular to the first die upper surface (311).

[0046] 3, the pouch sheet (200) is seated on the upper surface (311) of the first die so as to cover the mold opening (312). The lower surface (202) of the pouch sheet (200) is exposed to the upper part of the first die part (310) through the mold opening (312).

[0047] The pouch forming device (300) may also include a first pressure unit (320) for fixing the pouch sheet (200) to the first die unit (310). The first pressure unit (320) may be a stripper.

[0048] The pouch forming device (300) may also include a stretching section (330) including a first stretching member (331) arranged to apply pressure to a central region (A1) of the pre-forming region (A) of the pouch sheet (200), and a second stretching member (333) arranged to apply pressure to a first edge region (A2) surrounding the central region (A1).

[0049] As shown in FIG. 6, the first and second extension members (331, 333) may be configured to pressurize the central region (A1) and the first edge region (A2), respectively, along different directions (F1, F2) toward the mold opening (312).

[0050] The first stretching member (331) is disposed so as to be able to enter the mold opening (312) from the lower part of the first die part (310). The first stretching member (331) is disposed so as to be able to enter the center part of the mold opening (312). The first stretching member (331) is provided so as to be able to move up and down along the height direction (H).

[0051] The first stretching member (331) may have a curved surface at a portion thereof that comes into contact with the preforming area (A). The first stretching member (331) may have a first ball (332a) rotatably disposed at a portion thereof that comes into contact with the preforming area (A).

[0052] A first bearing member (332) having the first ball (332a) may be attached to the upper part of the first extension member (331). The first extension member (331) may be disposed so that the first ball (332a) can make point contact with the center of the central region (A1) on the lower surface of the pouch sheet (200).

[0053] When the first stretching member (331) presses the lower surface of the pouch sheet (200) in the first direction (F1), the first ball (332a) rotates counterclockwise or clockwise while in point contact with the lower surface of the pouch sheet (200), thereby dispersing the stress concentrated at the point of point contact of the first ball (332a) in a direction different from the first direction (F1).

[0054] The first extension member 331 is mounted on a lower support table 337a. A first driver 337 is mounted on the lower support table 337a. The first driver 337 moves the lower support table 337a up and down along the height direction H, thereby adjusting the direction and distance of movement of the first extension member 331.

[0055] The first driving unit (337) can operate to move the lower support table (337a) in a first direction (F1) from the bottom to the top of the mold opening (312) so that the first extension member (331) enters the mold opening (312).

[0056] When the first driving unit (337) is operated, the first stretching member (331) enters the mold opening (312) in the first direction (F1) along the height direction (H) and stretches the central region (A1) that contacts the lower surface of the pouch sheet (200) to the top of the mold opening (312).

[0057] The central region (A1) of the preforming region (A) can be stretched toward the upper part of the mold opening (312) by the force of the first stretching member (331) pressing in the first direction (F1). Hereinafter, for convenience of explanation, the portion of the central region (A1) that curves upward of the pouch sheet (200) will be referred to as the "first annular portion (231, see FIG. 8)."

[0058] The second extension member (333) is disposed so as to be able to enter the mold opening (312) from the upper part of the first die portion (310). The second extension member (333) is disposed so as to be able to enter the first edge region (A2) of the mold opening (312). The second extension member (333) is disposed so as to be able to move up and down along the height direction (H).

[0059] 4 and 5, the second extension member 333 may be provided to simultaneously press a plurality of first points along the circumferential direction of the first edge region A2, and the first points may be spaced apart from the center of the preforming region A by a first radius r1.

[0060] The second extension member 333 may be installed such that a virtual first line L1 connecting the plurality of first points forms a closed curve.

[0061] The second extension member 333 may be provided such that a virtual first line L1 connecting the plurality of first points has a circular shape having a radius larger than that of the central region A1.

[0062] The second extension member 333 may be provided so that a virtual first line L1 connecting the plurality of first points has a polygonal shape.

[0063] The second extension member (333) may have a curved surface at a portion that comes into contact with the preforming area (A).

[0064] A second bearing member (334) having a plurality of second balls (334a) may be attached to the lower section of the second extending member (333). The second balls (334a) are rotatably mounted in a portion that contacts the preforming area (A). The second balls (334a) may come into contact with the upper surface (201) of the pouch sheet (200) along an imaginary first line (L1).

[0065] The second extension member (333) may be arranged such that the plurality of second balls (334a) can be in point contact with the first edge region (A2) on the upper surface of the pouch sheet (200) along the virtual first line.

[0066] When the second stretching member (333) presses the upper surface of the pouch sheet (200) in the second direction (F2), each of the second balls (334a) rotates counterclockwise or clockwise while in point contact with the upper surface of the pouch sheet (200), thereby dispersing the stress concentrated at the point of point contact of each of the second balls (334a) in a direction different from the second direction (F2).

[0067] The second extension member 333 may be installed such that the plurality of first points are spaced apart from the central region A1 at a predetermined interval. The second extension member 333 is installed to surround the first extension member 331 when entering the mold opening 312.

[0068] The second extension member (333) is mounted on an upper support table (338). A second driving unit (339) is mounted on the upper support table (338). The second driving unit (339) moves the upper support table (338) up and down along the height direction (H) to adjust the direction and distance of movement of the second extension member (333).

[0069] The second extension member (333) is mounted on the upper support table (338) so as to surround the first extension member (331) when entering the mold opening (312).

[0070] The second driving unit (339) can operate to move the upper support table (338) in a second direction (F2) from the top to the bottom of the mold opening (312) so that the second extension member (333) enters the mold opening (312).

[0071] When the second driving unit (339) is operated, the second stretching member (333) enters the mold opening (312) in the second direction (F2) along the height direction (H) and stretches the first edge region (A2) that contacts the upper surface of the pouch sheet (200) to the bottom of the mold opening (312).

[0072] The first edge region (A2) of the pre-forming region (A) can be extended downward from the mold opening (312) by the pressure applied in the second direction (F2) by the second extension member (333). Hereinafter, for ease of explanation, the portion of the first edge region (A2) that curves downward from the pouch sheet (200) will be referred to as the "second annular portion (233, see FIG. 8)."

[0073] The stretching portion (330) may also include a third stretching member (335) that is provided to apply pressure to a second edge region (A3) that surrounds the first edge region (A2).

[0074] 3, the third extension member (335) is disposed so as to be able to enter the mold opening (312) from the lower part of the first die part (310). The third extension member (335) is disposed so as to be able to enter the second edge region (A3) of the mold opening (312). The third extension member (335) is disposed so as to be able to move up and down along the height direction (H).

[0075] The second stretching member (333) and the third stretching member (335) may be configured to pressurize the first edge region (A2) and the second edge region (A3), respectively, along different directions (F1, F2) toward the mold opening (312).

[0076] 4 and 5, the third extension member 335 may be configured to simultaneously press a plurality of second points along the circumferential direction of the second edge region A3, and the second points may be spaced apart from the center of the pre-forming region A by a second radius r2.

[0077] The third extension member (335) may have a curved surface at a portion that comes into contact with the preforming area (A).

[0078] The third extension member 335 may be installed such that a virtual second line L2 connecting the plurality of second points forms a closed curve.

[0079] The third extension member 335 may be provided such that a virtual second line L2 connecting the plurality of second points has a circular shape having a radius larger than that of the first edge region A2.

[0080] The third extension member 335 may be provided so that a virtual second line L2 connecting the plurality of second points has a polygonal shape.

[0081] The second stretching member (333) and the third stretching member (335) may be provided so that the first imaginary line (L1) and the second imaginary line (L2) each have a circular shape.

[0082] The second extension member (333) and the third extension member (335) may be provided so that the first imaginary line (L1) and the second imaginary line (L2) each have a polygonal shape.

[0083] A third bearing member 336 having a plurality of third balls 336a may be mounted on the upper section of the third extension member 335. The third balls 336a may be rotatably provided in a portion that contacts the preforming area A.

[0084] The third extension member (335) may be arranged such that the plurality of third balls (336a) can make point contact with the second edge region (A3) on the underside of the pouch sheet (200) along the imaginary second line (L2).

[0085] When the third extension member (335) presses the lower surface of the pouch sheet (200) in the first direction (F1), each of the third balls (336a) rotates counterclockwise or clockwise while in point contact with the lower surface of the pouch sheet (200), thereby dispersing the stress concentrated at the point of point contact of each of the third balls (336a) in a direction different from the first direction (F1).

[0086] The third extension member 335 is mounted on a lower support table 337a. A first driver 337 is mounted on the lower support table 337a. The first driver 337 moves the lower support table 337a up and down along the height direction H, thereby adjusting the direction and distance of movement of the third extension member 335.

[0087] The lower support table 337a moves the first and third extension members 331 and 335 together in the same direction. The third extension member 335 is attached to the lower support table 337a so as to surround the first extension member 331.

[0088] The third extension member (335) is spaced apart from the first extension member (331) at a predetermined interval along the width direction (W) of the mold opening (312). The third extension member (335) may be attached to the lower support stand (337a) so as to be adjacent to the inner surfaces (313, 314) of the mold opening (312) when inserted into the mold opening (312).

[0089] The first driving unit (337) can operate to move the lower support table (337a) in a first direction (F1) from the bottom to the top of the mold opening (312) so that the third extension member (335) enters the mold opening (312).

[0090] When the first driving unit (337) is operated, the third extension member (335) enters the mold opening (312) in the first direction (F1) along the height direction (H) and extends the second edge region (A3) that contacts the lower surface of the pouch sheet (200) to the top of the mold opening (312).

[0091] The second edge region (A3) of the pre-forming region (A) can be extended toward the upper portion of the mold opening (312) by the force of the first extension member (331) pressing in the first direction (F1). Hereinafter, for convenience of explanation, the portion of the second edge region (A3) curved toward the upper portion of the pouch sheet (200) will be referred to as the "third annular portion (235, see FIG. 8)."

[0092] The pouch forming apparatus (300) may also include a control unit (340) configured to control the movements of the first to third stretching members (331, 333, 335). The control unit (340) controls the operation of the first and second driving units (337, 339).

[0093] The control section (340) may be provided so that the first and third stretching members (331, 335) simultaneously pressurize the preforming region (A). The control section (340) may be provided so that the first to third stretching members (331, 333, 335) simultaneously pressurize the preforming region (A).

[0094] The control unit (340) can operate the first driving unit (337) to move the lower support table (337a) in the first direction (F1) by the forming depth (D) during the stretching operation of the pouch sheet (200), and can operate the second driving unit (339) to move the upper support table (338) in the second direction (F2) by the forming depth (D).

[0095] As described above, when the first driving unit 337 is operated, the lower support table 337a moves in the first direction F1. The first and third stretching members 331 and 335 move in the first direction F1 together with the lower support table 337a, thereby stretching the central region A1 and the second edge region A3 of the preforming region A to the upper part of the mold opening 312.

[0096] When the second driving unit (339) is operated, the upper support table (338) moves in the second direction (F2). The second stretching member (333) moves in the second direction (F2) together with the upper support table (338) to stretch the first edge region (A2) of the preforming region (A) to the bottom of the mold opening (312). The first edge region (A2) is the region between the center region (A1) and the second edge region (A3).

[0097] The second stretching member (333), together with the first and third stretching members (331, 335), presses the upper and lower surfaces of the pouch sheet (200) in different directions (F1, F2).

[0098] FIG. 8(a) is a perspective view of a pouch that has been primarily stretched according to one embodiment of the present invention, and FIG. 8(b) is a YY cross-sectional view of FIG. 8(a).

[0099] Referring to FIG. 8, through the above process, the main forming area (A10) obtained by the first stretching of the preliminary forming area (A) has the central area (A1) and the second edge area (A3) stretched to the top of the pouch sheet (200) to form a first annular portion (231) and a third annular portion (235), and the first edge area (A2) stretched to the bottom of the pouch sheet (200) to form a second annular portion (233).

[0100] The second annular portion (233) extends to the lower part of the first annular portion (231) and the third annular portion (235) along the height direction (H) and is provided to bend and connect the first annular portion (231) and the third annular portion (235).

[0101] The first to third annular portions (231, 233, 235) may have an annular shape with a circular cross section or a polygonal cross section depending on the shape of the first to third elongated members (331, 333, 335).

[0102] 9 and 10 are diagrams illustrating the process of forming a primarily stretched pouch into a pouch having a cup portion. FIG. 9 is a diagram illustrating the arrangement of the second die unit, the second pressure unit, and the punching unit, and FIG. 10 is a diagram illustrating the operation of the punching unit, in which the punching block of the punching unit is inserted into the mold groove of the second die unit.

[0103] As shown in Figures 9 and 10, the pouch forming apparatus (300) may include a second die section (360), a second pressure section (370) and a punching section (380) for forming the pouch (230) in which the pre-forming region (A) has been primarily stretched into a pouch (240, see Figure 11) having a cup section (241).

[0104] For example, the pouch (230) that has been primarily stretched in the preforming area (A) can be transferred to the second die section (360) through a transfer section such as a gripper and / or a conveyor.

[0105] The second die section (360) has a die groove (361) having a forming depth (D).

[0106] The mold groove 361 is provided to seat the main molding area A10, which is a primary extension of the pre-molding area A. The main molding area A10 is provided with a first annular portion 231, a second annular portion 233, and a third annular portion 235.

[0107] As shown in Figure 9, the primarily stretched pouch (230) can be seated in the mold groove (361) with the second annular portion (233) placed on the groove bottom (363) and the first annular portion (231) and the third annular portion (235) exposed at the top of the mold groove (361). In the primarily stretched pouch (230), the first annular portion (231), the second annular portion (233) and the third annular portion (235) are stretched to a uniform thickness.

[0108] The second pressure unit (370) is for fixing the primarily stretched pouch (230) to the second die unit (360). The second pressure unit (370) may be a stripper.

[0109] The punching section 380 includes a punching block 381 that is insertable into the mold groove 361. The punching block 381 is configured to extend the first annular section 231, the second annular section 233, and the third annular section 235 into the mold groove 361.

[0110] 10, the punching block 381 moves in the second direction F2 toward the mold groove 361, and presses the first annular portion 231 and the third annular portion 235 exposed at the top of the mold groove 361 while inserting them into the mold groove 361. Then, the punching block 381 presses the second annular portion 233 against the groove bottom surface 363.

[0111] FIG. 11(a) is a perspective view of a pouch provided with a cup portion according to one embodiment of the present invention, and FIG. 11(b) is a ZZ cross-sectional view of FIG. 11(a).

[0112] The pouch (230) that has been subjected to the first stretching process can be formed into a pouch (240, see FIG. 11) having a cup portion (241). As shown in FIG. 11, the cup portion (241, see FIG. 11) has a cup bottom (242) and cup corner portions (243, 244).

[0113] The cup bottom surface 242 is an extension of the first and second annular portions 231 and 233 so as to contact the groove bottom surface 363. The cup corner portions 243 and 244 are extensions of the third annular portion 235 so as to contact the groove corner portions 367 and 368 of the mold groove 361. The cup corner portions 243 and 244 are portions that connect the inner surface of the cup portion 241 (see FIG. 11) that extends in the height direction (H) from the cup bottom surface 242.

[0114] Conventionally, the punching block (30, see FIG. 1) stretches the flat preforming area (A) in the mold groove (161). Here, stress is concentrated at the cup corners (4, 5) that contact the block corners (34, 35) of the punching block (30, see FIG. 1), causing the cup corners (4, 5, see FIG. 2) to be stretched more than the cup bottom (3, see FIG. 2), resulting in the cup corners (4, 5, see FIG. 2) being thinner than the cup bottom (3, see FIG. 2).

[0115] As shown in Figure 2, the conventional cup portion (2, see Figure 2) has problems such as cracks or breakage in the cup corner portions (4, 5) because the cup corner portions (4, 5) are formed thinner than the cup bottom (3). Such damage to the cup portion (2) can lead to secondary problems such as electrolyte leakage and battery cell explosion due to electrolyte leakage.

[0116] In contrast, the present invention is configured to primarily stretch the preforming region (A) so as to bend it, and then mold the primarily stretched preforming region (A) into a cup portion (241, see FIG. 11). As a result, when the punching block (381) presses the primarily stretched preforming region (A) into the mold groove (361), stress concentration at the cup corners (243, 244) that contact the block corners (382) of the punching block (381) is eliminated, and the cup corners (243, 244) and the cup bottom (242) can be formed to a uniform thickness.

[0117] As a result, the present invention can prevent damage to the cup portion (241, see FIG. 11) during the pouch manufacturing process, and can prevent secondary problems such as electrolyte leakage caused by damage to the cup portion (241, see FIG. 11) and / or explosion of the battery cell due to electrolyte leakage.

[0118] The preferred embodiments of the present invention described above have been disclosed for illustrative purposes, and those skilled in the art with ordinary skill in the art may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims. [Industrial Applicability]

[0119] According to a pouch forming apparatus related to one embodiment of the present invention, a preforming region of a pouch sheet can be primarily stretched, and then the primarily stretched preforming region can be secondarily stretched to form a cup portion.

Claims

1. A pouch forming device for forming a cup portion in a preforming area of ​​a pouch sheet, a first die portion having a mold opening, the preforming area covering the mold opening, and the pouch sheet seated thereon; a first pressurizing unit for fixing the pouch sheet to the first die unit; a stretching unit including a first stretching member provided to apply pressure to a central region of the pre-forming region of the pouch sheet, and a second stretching member provided to apply pressure to a first edge region surrounding the central region; A pouch forming device, wherein the first stretching member and the second stretching member are configured to pressurize the central region and the first edge region, respectively, along different directions toward the mold opening.

2. the second extension member is configured to simultaneously press a plurality of first points along a circumferential direction of the first edge region, 2. The pouch forming apparatus according to claim 1, wherein the second stretching member is provided such that the plurality of first points are spaced apart from the central region by a predetermined distance.

3. 3. The pouch forming apparatus according to claim 2, wherein the second stretching member is provided so that a virtual first line connecting the plurality of first points forms a closed curve.

4. 3. The pouch forming apparatus according to claim 2, wherein the second stretching member is provided so that an imaginary first line connecting the plurality of first points has a circular shape having a radius larger than that of the central region.

5. 3. The pouch forming apparatus according to claim 2, wherein the second stretching member is provided so that a virtual first line connecting the plurality of first points has a polygonal shape.

6. the stretching unit further includes a third stretching member provided to apply pressure to a second edge region surrounding the first edge region; 2. The pouch forming apparatus according to claim 1, wherein the second stretching member and the third stretching member are configured to pressurize the first edge region and the second edge region, respectively, along different directions toward the mold opening.

7. 7. The pouch forming apparatus according to claim 6, wherein the third stretching member is configured to simultaneously pressurize a plurality of second points along a circumferential direction of the second edge region.

8. 8. The pouch forming apparatus according to claim 7, wherein the third stretching member is provided so that a virtual second line connecting the plurality of second points forms a closed curve.

9. 8. The pouch forming apparatus according to claim 7, wherein the third stretching member is provided so that a virtual second line connecting the plurality of second points has a circular shape having a radius larger than that of the first edge region.

10. 8. The pouch forming apparatus according to claim 7, wherein the third stretching member is provided so that a virtual second line connecting the plurality of second points has a polygonal shape.

11. a controller configured to control movement of the first stretching member, the second stretching member, and the third stretching member; 7. The pouch forming apparatus according to claim 6, wherein the control unit is provided so that the first stretching member and the third stretching member simultaneously pressurize the preforming region.

12. 12. The pouch forming apparatus according to claim 11, wherein the control unit is provided so that the first stretching member, the second stretching member, and the third stretching member simultaneously pressurize the preforming region.

13. 7. The pouch forming apparatus according to claim 6, wherein the first stretching member, the second stretching member, and the third stretching member have curved portions formed in their portions that come into contact with the preforming region.

14. 7. The pouch forming apparatus according to claim 6, wherein the first stretching member, the second stretching member, and the third stretching member have balls rotatably arranged in portions that come into contact with the preforming area.

15. a second die portion provided with a die groove in which the preforming region, which has been formed through the extension portion, is seated; a second pressurizing unit for fixing the pouch sheet seated on the second die unit; 2. The pouch forming apparatus according to claim 1, further comprising: a punching unit including a punching block that is insertable into the mold groove and that is configured to extend the pre-forming region within the mold groove.

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