Apparatus for manufacturing pouch of secondary battery

Abstract

This invention relates to an apparatus for manufacturing bags for secondary batteries, and more specifically, to an apparatus for manufacturing bags for secondary batteries that can reduce or eliminate bag wrinkles that occur during bag molding when the bag substrate is unevenly sucked up without additional means. The apparatus for manufacturing bags for secondary batteries according to the invention comprises: a lower mold having a receiving groove formed in a base surface on which the bag is disposed for molding a cup portion of the bag; a punch inserted into the receiving groove of the lower mold to mold the cup portion of the bag; and a demolding device configured to press the outer periphery of the bag from above, the outer periphery of which is disposed on the outer periphery of the portion to be molded into the cup portion of the bag by the punch, wherein the demolding device and the lower mold press and hold the upper and lower portions of the outer periphery of the bag, respectively; while the outer periphery of the bag is held by the demolding device and the lower mold, the punch is inserted into the receiving groove to mold the cup portion of the bag, and a friction region is formed on the pressing surface of the lower mold or the demolding device pressing the outer periphery of the bag, the friction region being a region having a surface roughness greater than that of the outer periphery.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0138674, filed on October 23, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to an apparatus for manufacturing bags for secondary batteries, and more specifically, to an apparatus for manufacturing bags for secondary batteries that can reduce or eliminate bag wrinkles that occur during the molding of the bag when the bag substrate is unevenly drawn, without the need for additional equipment. Background Technology

[0004] In recent years, rising energy prices due to the depletion of fossil fuels have amplified concerns about environmental pollution, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor in future life. Therefore, research into various power generation technologies such as solar, wind, and tidal power is ongoing, and energy storage devices such as batteries are receiving significant attention to more effectively utilize the generated electricity.

[0005] Furthermore, with technological advancements and the increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is also rapidly increasing. Therefore, much research has been conducted on batteries capable of meeting diverse needs.

[0006] In particular, there is a high demand for lithium-ion batteries and lithium-ion polymer batteries, which have advantages such as high energy density, high discharge voltage and high output stability.

[0007] Based on the shape of the battery casing, secondary batteries are divided into cylindrical batteries and square batteries, in which the electrode components are built into cylindrical or prismatic metal cans, and pouch batteries, in which the electrode components are built into pouch-shaped casings made of aluminum laminates.

[0008] Figure 1 An example of a pouch-type secondary battery is illustrated. The pouch-type secondary battery 1 includes: an electrode assembly 20 in which electrodes and separators are alternately stacked; and a pouch 10 for inserting the electrode assembly. Furthermore, the pouch includes cup portions 11 and 12, each cup portion 11 and 12 having a recessed shape to directly accommodate the electrode assembly. The cup portions of the pouch are provided with a left pouch cup portion 11 and a right pouch cup portion 12, thereby surrounding the electrode assembly on both sides. An outer peripheral portion 14 of the pouch is formed around the outer periphery of each cup portion to seal the pouch to the outside.

[0009] in particular, Figure 1The bag shown can be a V-shaped bag 10. According to related technology, the bag is manufactured in a flat form. However, recently, the bag can be manufactured as a V-shaped bag so that the bag is manufactured neatly to prevent bulges from appearing on the surface of the bag during the bag folding process. Furthermore, such a V-shaped bag can be manufactured by bag manufacturing equipment that forms a molding die.

[0010] However, when using a molding die for manufacturing V-shaped bags to mold the bags, there is a problem that the bag material is unevenly sucked in at certain locations, resulting in bag wrinkles. Figure 2 This diagram illustrates the state of folds between the cup portion 11 of the left pocket and the cup portion 12 of the right pocket. Specifically, as... Figure 2 As shown, there is a problem of bag wrinkles occurring at the end of the bag bridging portion 13 (see...). Figure 1 and Figure 2 (The dashed line in the middle). Summary of the Invention

[0011] Technical issues

[0012] The present invention is designed to solve the above-mentioned problems, and the object of the present invention is to provide an apparatus for manufacturing bags for secondary batteries that can reduce or eliminate bag wrinkles that occur during the molding of the bag when the bag substrate is unevenly sucked up without the need for additional equipment.

[0013] Technical solution

[0014] An apparatus for manufacturing a bag for a secondary battery according to the present invention includes: a lower mold having a receiving groove formed in a base surface on which the bag is disposed for molding a cup portion of the bag; a punch inserted into the receiving groove of the lower mold to mold the cup portion of the bag; and a demolding device configured to press an outer periphery of the bag from above, the outer periphery of the bag being disposed on the outer periphery of a portion to be molded into the cup portion of the bag by the punch, wherein the demolding device and the lower mold press and clamp the upper and lower portions of the outer periphery of the bag, respectively, wherein the punch is inserted into the receiving groove to mold the cup portion of the bag while the outer periphery of the bag is clamped by the demolding device and the lower mold, and a friction region is formed on the pressing surface of the lower mold or the demolding device pressing the outer periphery of the bag, the friction region being a region having a surface roughness greater than that of the outer periphery.

[0015] The friction area may include a first friction area formed on the lower mold.

[0016] Two receiving grooves, namely a left receiving groove and a right receiving groove, can be formed in the lower mold.

[0017] A bridging portion connecting the two receiving slots can be formed between the left receiving slot and the right receiving slot, and

[0018] The first friction area may be formed on the outer region of the bridging portion, which is the region on the base surface located outside the bridging portion.

[0019] The first friction area may be formed to be separated from each of the two ends of the bridging portion by a predetermined distance.

[0020] The first friction area may be formed to be separated from each of the two ends of the bridging portion by a distance of 5 mm or more.

[0021] The friction area may include a second friction area formed on the demolding device.

[0022] Two receiving grooves, namely a left receiving groove and a right receiving groove, can be formed in the lower mold.

[0023] A bridging portion connecting the two receiving slots can be formed between the left receiving slot and the right receiving slot, and

[0024] The second friction area may be formed on the outer region of the demolding device, which is the pressing surface of the demolding device, the outer region of the demolding device facing the outer region of the bridging portion, the outer region of the bridging portion being the region on the base surface located outside the bridging portion.

[0025] The second friction area may be formed to be separated from each of the points of the demolding device corresponding to the two ends of the bridging portion by a predetermined distance.

[0026] The second friction area may be formed to be separated from each of the points of the demolding device corresponding to the two ends of the bridging portion by a distance of 5 mm or more.

[0027] The friction area may include a first friction area formed on the lower mold and a second friction area formed on the demolding device.

[0028] Two receiving grooves, namely a left receiving groove and a right receiving groove, can be formed in the lower mold.

[0029] A bridging portion connecting the left and right receiving slots can be formed between them.

[0030] The first friction area may be formed on the outer region of the bridging portion, which is the region on the base surface located outside the bridging portion, and the second friction area may be formed on the outer region of the demolding device, which serves as the pressing surface of the demolding device, and the outer region of the demolding device faces the outer region of the bridging portion.

[0031] The first friction area may be formed to be separated from each of the two ends of the bridging portion by a predetermined distance, and the second friction area may be formed to be separated from the points of the demolding device corresponding to each of the two ends of the bridging portion by a predetermined distance.

[0032] The first friction area may be formed to be separated from each of the two ends of the bridging portion by a distance of 5 mm or more, and the second friction area may be formed to be separated from the points of the demolding device corresponding to each of the two ends of the bridging portion by a distance of 5 mm or more.

[0033] The pressure applied by the demolding device and the lower mold to the outer periphery of the bag in the friction area is 10% to 30% greater than the reference pressure, which is the pressure applied to the outer periphery of the bag outside the friction area.

[0034] The reference pressure can be from 0.3 bar to 0.35 bar.

[0035] Beneficial effects

[0036] The apparatus for manufacturing a bag for a secondary battery according to the present invention includes: a lower mold having a receiving groove formed in a base surface on which the bag is disposed for molding a cup portion of the bag; a punch inserted into the receiving groove of the lower mold to mold the cup portion of the bag; and a demolding device configured to press the outer periphery of the bag from above, the outer periphery of which is disposed on the outer periphery of the portion to be molded into the cup portion of the bag by the punch, wherein the demolding device and the lower mold press and hold the upper and lower portions of the outer periphery of the bag, respectively, and the punch is inserted into the receiving groove to mold the cup portion of the bag while the outer periphery of the bag is held by the demolding device and the lower mold, and a friction region is formed on the pressing surface of the lower mold or the demolding device pressing the outer periphery of the bag, the friction region being a region having a surface roughness greater than that of the outer periphery, thereby reducing or eliminating bag wrinkles that occur during the molding of the bag when the bag substrate is unevenly sucked without additional means. Attached Figure Description

[0037] Figure 1 This is an exploded perspective view of the V-shaped bag and the electrode assembly built into the V-shaped bag.

[0038] Figure 2 This is a diagram showing how it appears when viewed from below. Figure 1 The dashed lines represent the shape of the portion in the perspective view.

[0039] Figure 3 This is a front view illustrating the apparatus for manufacturing bags for secondary batteries according to the present invention, specifically a front view showing the punch and demolding device in a state away from the lower mold before the bag is molded.

[0040] Figure 4 This is a front view illustrating the apparatus for manufacturing bags for secondary batteries according to the present invention, specifically a front view showing the punch and demolding device close to the lower mold to mold the bag.

[0041] Figure 5 These are front and plan views of the lower mold in an apparatus for manufacturing a bag for a secondary battery according to Embodiment 1 of the present invention.

[0042] Figure 6 These are front and bottom views of the demolding device and punch in an apparatus for manufacturing bags for secondary batteries according to Embodiment 2 of the present invention. Detailed Implementation

[0043] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings to enable those skilled in the art to readily implement the invention. However, the invention may be implemented in several different forms and is not limited to or construed as follows.

[0044] To clearly explain the invention, detailed descriptions of relevant known technologies that are irrelevant to the description or may unnecessarily obscure the spirit of the invention have been omitted, and in this specification, reference numerals are added to components in each drawing. In this case, throughout the application, the same or similar reference numerals are assigned to the same or similar elements.

[0045] Furthermore, the terms or words used in this specification and claims should not be construed as having a general meaning or a dictionary-based meaning, but should be interpreted as meanings and concepts that are within the scope of this invention, based on the principle that the inventor can properly define the concepts of the terms in order to best describe and interpret his or her invention.

[0046] Implementation Method 1

[0047] Figure 3 This is a front view illustrating the apparatus for manufacturing bags for secondary batteries according to the present invention, specifically a front view showing the punch and demolding device in a state away from the lower mold before the bag is molded. Figure 4 This is a front view illustrating the apparatus for manufacturing bags for secondary batteries according to the present invention, specifically a front view showing the punch and demolding device close to the lower mold to mold the bag. Figure 5 These are front and plan views of the lower mold in an apparatus for manufacturing a bag for a secondary battery according to Embodiment 1 of the present invention. Figure 5 In the diagram, the upper part is a plan view (the base plane when viewed from above), while the lower part is a front view.

[0048] Reference Figures 3 to 5According to Embodiment 1 of the present invention, the apparatus 100 for manufacturing a bag for a secondary battery includes a lower mold 110, a punch 150, and a demolding device 130.

[0049] The lower mold 110 can be positioned below to mold the bag and may have a base surface 114 on which the bag is disposed. Furthermore, the lower mold 110 has receiving grooves 111, 112 on the base surface 114 for molding the cup portion of the bag. The punch 150 can be configured to mold the cup portion of the bag while being inserted into the receiving groove of the lower mold 110. The ejector 130 can be configured to press the outer periphery of the bag from above, the outer periphery of which is located on the outer periphery of the portion to be molded into the cup portion of the bag by the punch 150.

[0050] The demolding device 130 and the lower mold 110 can press and clamp the upper and lower parts of the outer periphery of the bag, respectively. While the outer periphery of the bag is clamped by the demolding device 130 and the lower mold 110, the punch 150 can be inserted into the receiving groove to mold the cup part of the bag.

[0051] In the apparatus 100 for manufacturing a secondary battery bag according to Embodiment 1 of the present invention, a friction region may be formed on the pressing surface of the lower mold 110 or the demolding device 130 that presses the outer periphery of the bag. The friction region is a region having a surface roughness greater than that of the outer periphery.

[0052] In this embodiment, the friction region may refer to a region with a surface rougher than other regions. The lower mold 110 may be made of metal, and in this case, the friction region may refer to a rough metal surface. For example, the base surface 114 of the lower mold 110 may be polished to a smooth finish, but only the friction region may not be polished, so that the friction region remains a surface rougher than other regions to form the friction region.

[0053] According to related technologies, methods for inserting fillers or springs have been used to partially increase the clamping pressure at specific locations. However, the problem with this method is that setting up additional mechanisms is inconvenient, and the metal can deform when using the added mechanisms cumulatively.

[0054] On the other hand, the method of forming a friction zone on a metal mold according to the present invention has the advantage of not requiring additional mechanisms such as fillers. Furthermore, since a method without inserting additional mechanisms is used, it has the advantage of preventing deformation of the metal (metal mold).

[0055] The V-shaped bag having the above-described structure can be manufactured using the apparatus 100 for manufacturing bags of secondary batteries according to Embodiment 1 of the present invention.

[0056] Reference Figure 5The friction area may include a first friction area 115 formed on the lower mold 110. In the apparatus 100 for manufacturing a bag for a secondary battery according to Embodiment 1 of the present invention, the friction area may be formed only on the lower mold 110, and no friction area may be formed on the upper demolding device 130. In this case, the friction area formed on the lower mold may be the first friction area 115.

[0057] Two receiving grooves, namely a left receiving groove 111 and a right receiving groove 112, can be formed in the lower mold 110. The cup portion of the left bag can be formed through the left receiving groove 111. The cup portion of the right bag can be formed through the right receiving groove 112.

[0058] A bridging portion 113 connecting the two receiving grooves can be formed between the left receiving groove 111 and the right receiving groove 112. In addition, a first friction region 115 can be formed on the outer region of the bridging portion, which is the region on the base surface 114 located outside the bridging portion 113. Figure 5 The diagram illustrates the state in which the first friction region 115 is formed on the outer regions of the upper and lower bridging portions.

[0059] In the apparatus 100 for manufacturing a secondary battery bag according to Embodiment 1 of the present invention, bag wrinkles that occur during the molding of the bag when the bag substrate is unevenly sucked up can be reduced or eliminated without the need for additional equipment.

[0060] In other words, according to relevant technologies, when the roughness on the base surface 114 of the current mold 110 is uniform, a relatively larger amount of bag substrate can be drawn into the end of the bridging portion 113, resulting in bag wrinkles. However, the apparatus 100 for manufacturing bags for secondary batteries according to Embodiment 1 of the present invention can have a friction area in a specific region to prevent the bag from being drawn into the bridging portion 113 so that only the necessary amount is drawn in, thereby preventing bag wrinkles.

[0061] When the punch molds a bag while the punch 150 is received in the receiving groove, a predetermined amount of bag substrate can be drawn up entirely during the molding process. However, a relatively larger amount of bag substrate can be drawn up at the end of the bridging portion 113, resulting in bag wrinkles. However, these causes and problems can be solved in the apparatus for manufacturing bags for secondary batteries according to Embodiment 1 of the present invention.

[0062] In the apparatus 100 for manufacturing a pouch for a secondary battery according to Embodiment 1 of the present invention, the first friction region 115 may be formed at a predetermined distance from each of the two ends of the bridging portion 113. Specifically, the first friction region 115 may be formed at a distance of 5 mm or greater from each of the two ends of the bridging portion 113. That is, Figure 5 The value d1 can be 5mm or larger.

[0063] When the separation distance dl between each of the two ends of the first friction area 115 and the bridging portion 113 is less than 5 mm, the amount of bag substrate that can be pushed inward may be insufficient, and therefore, the bag may rupture in the corresponding portion. As a result, the value that can solve all these problems corresponds to the case where the value d1 is 5 mm or greater.

[0064] Furthermore, the pressure applied by the demolding device 130 and the lower mold 110 to the bag (more precisely, the outer periphery of the bag) on ​​the first friction area 115 can be 10% to 30% greater than the pressure applied by the demolding device 130 and the lower mold 110 to the bag (more precisely, the outer periphery of the bag) in areas other than the first friction area 115.

[0065] Here, if the pressure applied to the bag by the demolding device 130 and the lower mold 110 on the area outside the first friction area 115 is referred to as the reference pressure, then the reference pressure can be 0.3 bar to 0.35 bar.

[0066] In this case, when the reference pressure is 0.3 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the first friction area 115 can be from 0.33 bar to 0.39 bar.

[0067] Furthermore, when the reference pressure is 0.35 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the first friction area 115 can be from 0.385 bar to 0.455 bar.

[0068] Implementation Method 2

[0069] Figure 6 These are front and bottom views of the demolding device 130 and punch 150 in the apparatus for manufacturing bags of secondary batteries according to Embodiment 2 of the present invention (the upper view is the front view and the lower view is the bottom view).

[0070] The difference between Embodiment 2 and Embodiment 1 is that the friction area is formed on the demolding device 130 disposed on the upper side.

[0071] Descriptions of Embodiment 2 will focus on the differences and omit as much content as possible that overlaps with Embodiment 1. That is, it is obvious that, if necessary, any content not described in Embodiment 2 can be considered as part of Embodiment 1.

[0072] Reference Figure 6 In the apparatus 200 for manufacturing secondary battery bags according to Embodiment 2 of the present invention, a friction region may be formed on the demolding device 130. The friction region formed on the demolding device 130 may be a second friction region 132.

[0073] Similar to Embodiment 1, two receiving grooves, namely a left receiving groove 111 and a right receiving groove 112, can be formed in the lower mold 110, and a bridging portion 113 connecting the two receiving grooves to each other can be formed between the left receiving groove 111 and the right receiving groove 112.

[0074] The second friction area 132 can be formed on the outer region 131 of the demolding device, which serves as the pressing surface of the demolding device 130. The outer region 131 of the demolding device faces the outer region of the bridging portion, which is the region on the base surface 14 located outside the bridging portion 113. That is, the outer region 131 of the demolding device can be the region facing the region located outside the bridging portion 113, and the outer region 131 of the demolding device and the region located outside the bridging portion 113 can clamp the upper and lower parts of the bag (more precisely, the outer periphery of the bag).

[0075] Furthermore, in the apparatus 200 for manufacturing a secondary battery bag according to Embodiment 2 of the present invention, the second friction region 132 may be formed at a predetermined distance from each point of the demolding device 130 corresponding to each of the two ends of the bridging portion 113. In particular, the second friction region 132 may be formed at a distance of 5 mm or greater from each point of the demolding device 130 corresponding to each of the two ends of the bridging portion 113. That is to say, Figure 6 The value d2 can be 5mm or larger.

[0076] When the separation distance d2 between the second friction zone 132 and each of the two ends of the demolding device 130 corresponding to the bridging portion 113 is less than 5 mm, the amount of material that can be pushed inward may be insufficient, and therefore the bag may rupture in the corresponding portion. As a result, the value that can solve all these problems corresponds to the case where the value d2 is 5 mm or greater.

[0077] Furthermore, the pressure applied by the demolding device 130 and the lower mold 110 to the outer periphery of the bag in the second friction area 132 can be 10% to 30% greater than the pressure applied by the demolding device 130 and the lower mold 110 to the outer periphery of the bag in areas other than the second friction area 132.

[0078] Here, if the pressure applied by the demolding device 130 and the lower mold 110 to the bag in the area other than the second friction area 132 is called the reference pressure, then the reference pressure can be 0.3 bar to 0.35 bar.

[0079] In this case, when the reference pressure is 0.3 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the second friction area 132 can be from 0.33 bar to 0.39 bar.

[0080] Furthermore, when the reference pressure is 0.35 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the second friction area 132 can be from 0.385 bar to 0.455 bar.

[0081] Implementation Method 3

[0082] The difference between Embodiment 3 of the present invention and Embodiments 1 and 2 is that a friction area is formed on each of the lower mold 110 and the demolding device 130.

[0083] Descriptions of Embodiment 3 will focus on the differences, omitting as much content as possible that overlaps with Embodiments 1 and 2. That is, it is evident that any content not described in Embodiment 3 may be considered part of Embodiments 1 and 2 if necessary.

[0084] Reference Figure 5 and Figure 6 In the apparatus for manufacturing a bag for a secondary battery according to Embodiment 3 of the present invention, a friction area may be formed on each of the lower mold 110 and the demolding device 130. That is, the apparatus for manufacturing a bag for a secondary battery according to Embodiment 3 of the present invention may include, for example... Figure 5 The lower mold 110 shown and as Figure 6 The demolding device 130 and punch 150 are shown.

[0085] Specifically, the friction area may include a first friction area 115 formed on the lower mold 110 and a second friction area 132 formed on the demolding device 130.

[0086] The first friction region 115 may be formed on the outer region of the bridging portion, which is the region on the base surface 114 located outside the bridging portion 113. The second friction region 132 may be formed on the outer region 131 of the demolding device, which is the pressing surface of the demolding device 130, facing the region on the base surface 114 located outside the bridging portion 113.

[0087] The first friction region 115 may be formed to be separated from each of the two ends of the bridging portion 113 by a predetermined distance, and the second friction region 132 may be separated from the points of the demolding device 130 corresponding to each of the two ends of the bridging portion 113 by a predetermined distance.

[0088] In particular, the first friction area 115 may be formed to be separated from each of the two ends of the bridging portion 113 by a distance of 5 mm or more, and the second friction area 132 may be separated from the points of the demolding device 130 corresponding to each of the two ends of the bridging portion 113 by a distance of 5 mm or more.

[0089] Furthermore, the pressure applied by the demolding device 130 and the lower mold 110 to the outer periphery of the bag in the friction area can be 10% to 30% greater than the pressure applied by the demolding device 130 and the lower mold 110 to the outer periphery of the bag in areas outside the friction area.

[0090] Here, if the pressure applied by the demolding device 130 and the lower mold 110 to the bag in the area outside the friction area is called the reference pressure, then the reference pressure can be from 0.3 bar to 0.35 bar.

[0091] In this case, when the reference pressure is 0.3 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the friction area can be from 0.33 bar to 0.39 bar.

[0092] Furthermore, when the reference pressure is 0.35 bar, the pressure applied by the demolding device 130 and the lower mold 110 to the bag on the friction area can be from 0.385 bar to 0.455 bar.

[0093] Although embodiments of the invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

[0094] [Marker Explanation]

[0095] 1: Secondary battery

[0096] 10: bag

[0097] 11: The cup section of the left pocket

[0098] 12: The cup section of the right pocket

[0099] 13: Pocket bridge joint

[0100] 14: The outer perimeter of the bag

[0101] 100, 200: Equipment for manufacturing bags for secondary batteries

[0102] 110: Lower mold

[0103] 111: Left receiving slot

[0104] 112: Right receiving slot

[0105] 113: Bridging section

[0106] 114: Base plane

[0107] 115: First friction zone

[0108] 130: Demolding device

[0109] 131: External area of ​​the demolding device

[0110] 132: Second friction zone

[0111] 150: Punch.

Claims

1. An apparatus for manufacturing a bag for secondary batteries, the apparatus comprising: A lower mold in which a receiving groove for molding the cup portion of the bag is formed in the base surface on which the bag is disposed; A punch, which is inserted into the receiving groove of the lower mold to mold the cup portion of the bag; and A release device configured to press down on the outer periphery of the bag from above, the outer periphery of which is located on the outer periphery of the cup portion to be molded into the bag by the punch. The release device and the lower mold respectively press and clamp the upper and lower parts of the outer periphery of the bag. With the outer periphery of the bag held by the demolding device and the lower mold, the punch is inserted into the receiving groove to mold the cup portion of the bag, and A friction region is formed on the pressing surface of the outer periphery of the bag by the lower mold or the demolding device. The friction region is a region with a surface roughness greater than that of the outer periphery. The friction area includes a first friction area formed on the lower mold. The lower mold contains two receiving grooves, namely a left receiving groove and a right receiving groove. A bridging portion is formed between the left receiving groove and the right receiving groove to connect the two receiving grooves to each other, and The first friction region is formed on the outer region of the bridging portion, which is the region on the base surface located on the outside of the bridging portion. The bag is a V-shaped bag, and the outer region of the bridging portion has a V-shape.

2. The device according to claim 1, wherein the first friction region is formed to be separated from each of the two ends of the bridging portion by a predetermined distance.

3. The device according to claim 2, wherein the first friction area is formed to be separated from each of the two ends of the bridging portion by a distance of 5 mm or greater.

4. The device according to claim 1, wherein the friction region further comprises a second friction region formed on the demolding device.

5. The device according to claim 4, wherein The second friction area is formed on the outer region of the demolding device, which serves as the pressing surface of the demolding device, and the outer region of the demolding device faces the outer region of the bridging portion.

6. The device according to claim 5, wherein the second friction area is formed to be separated from each of the points of the demolding device corresponding to the two ends of the bridging portion by a predetermined distance.

7. The device according to claim 6, wherein the second friction area is formed to be separated from each of the points of the demolding device corresponding to the two ends of the bridging portion by a distance of 5 mm or greater.

8. The device according to claim 4, wherein the first friction region is formed to be separated from each of the two ends of the bridging portion by a predetermined distance, and The second friction area is formed to be separated from each of the points of the demolding device corresponding to the two ends of the bridging portion by a predetermined distance.

9. The device according to claim 8, wherein the first friction region is formed to be spaced 5 mm or more from each of the two ends of the bridging portion, and The second friction area is formed to be separated from each of the two ends of the demolding device corresponding to the bridging portion by a distance of 5 mm or more.

10. The apparatus of claim 1, wherein the pressure applied by the demolding device and the lower die to the outer periphery of the bag in the friction area is 10% to 30% greater than a reference pressure, the reference pressure being the pressure applied to the outer periphery of the bag outside the friction area.

11. The device of claim 10, wherein the reference pressure is 0.3 bar to 0.35 bar.

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