Pouch forming apparatus

Abstract

The present invention relates to a pouch forming apparatus for forming a cup part on a pouch sheet, the pouch forming apparatus comprising: a die which has a nest formed on the top surface thereof and having a concavely recessed shape, and a flat portion formed along the periphery of the nest; a stripper for pressing and fixing a portion of the pouch sheet placed on the flat portion when the pouch sheet is seated on the die; and a punch for pressing the pouch sheet to enter the nest so as to form a cup portion on the pouch sheet, wherein a bead protrudes from the surface of the flat portion, and the bead is formed to form a curved shape on the flat portion.

Description

Pouch forming device

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0092602, filed July 17, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a pouch forming device for manufacturing a pouch used in a secondary battery, and more specifically, to a pouch forming device capable of suppressing or preventing the occurrence of wrinkles and / or breakage during processing of a pouch sheet.

[0003]

[0004] With the rapid development of the electrical, electronics, communications, and computer industries, the demand for high-performance, high-safety secondary batteries is steadily increasing. In particular, the rapid proliferation of miniaturization, thinning, and lightweight electronic devices is driving the demand for smaller, thinner secondary batteries. To meet this demand, lithium secondary batteries, with their high energy density, have recently attracted the most attention.

[0005] Lithium secondary batteries have the advantages of long life and large capacity, and are recently being widely used in portable electronic devices. Depending on the type of electrolyte, the lithium secondary batteries include lithium metal secondary batteries that use liquid electrolytes, lithium ion secondary batteries, and lithium polymer secondary batteries that use polymer solids.

[0006] In addition, lithium secondary batteries can be classified into square secondary batteries using square cans, cylindrical secondary batteries using cylindrical cans, and pouch-type secondary batteries using pouches, depending on the type of outer material that seals the electrode assembly.

[0007] In addition, pouch-type secondary batteries have many advantages, such as high energy density per unit weight and volume, making it possible to make secondary batteries thinner and lighter, and lowering the cost of materials as outer materials, so their development is actively underway recently.

[0008] Pouch-type secondary batteries are generally manufactured in the following order: First, the positive and negative electrodes are manufactured, a separator is interposed between them, and then they are laminated to create an electrode assembly.

[0009] Then, the electrode assembly is inserted into the pouch together with the electrolyte.

[0010] At this time, the pouch is manufactured by laminating a metal layer (foil) and a synthetic resin layer on the upper and lower surfaces of the metal layer, and a cup portion, which is a fine space, is formed to a size in which the electrode assembly can be mounted.

[0011] Fig. 1a is a drawing showing a pouch sheet (1) inserted into a conventional pouch forming device, Fig. 1b is a drawing showing a punch (6) lowered in a state where a stripper (5) is lowered and a pouch sheet (1) is fixed in the state of Fig. 1a, and Fig. 1c is a drawing showing a conventional die (2) viewed from above.

[0012] In a conventional pouch forming device, when a thin plate-shaped pouch sheet (1) having a predetermined thickness enters between a stripper (5) and a die (2), the stripper (5) is lowered downward so that the pouch sheet (1) is fixed between the upper surface of the die (2) and the bottom surface of the stripper (5).

[0013] And, when the punch (6) descends and applies pressure, the pouch sheet (1) is elongated to form a cup portion (1a). Accordingly, a nest (3) is formed in a concave fine shape on the upper surface of the die (2) so that the punch (6) can enter and descend to a predetermined depth. And, a flat portion (4) forming the upper surface is formed along the perimeter of the nest (3).

[0014] Accordingly, the stripper (5) fixes the pouch sheet (1) on the flat portion (4) of the die (2), and the punch (6) presses and stretches the pouch sheet (1) on the inner surface of the nest (3) to form the cup portion (1a). As illustrated, the die (2) has a structure in which a flat portion (4) is formed on each side with the nest (3) interposed therebetween, and a stripper (5) is positioned on each side of the punch (6) entering the nest (3).

[0015] Meanwhile, in order to prevent slipping of the pouch sheet (1) when the punch (6) is lowered, a bead (4a) protruding convexly from the surface to a predetermined height is formed on the flat portion (4) of the die (2). In the conventional structure, the bead (4a) is formed in a straight line on both sides of the nest (3) as shown in Fig. 1c.

[0016] In addition, the pouch sheet (1) is provided in a structure in which a synthetic resin layer is laminated on both sides of a metal layer in the middle. That is, the pouch sheet is provided as a composite sheet in which an outer layer made of nylon, etc., a barrier layer made of aluminum, etc., and a sealant layer (inner layer) made of PP, etc. are laminated.

[0017] The above pouch sheet (1) begins forming when it is touched by the punch (6), and is stretched along the full length and full width of the punch (6). At this time, the area not pressed by the bead (4a) is pushed toward the nest (3) (stretching occurs).

[0018] At this time, as shown in Fig. 1c, since the nest (3) has a square shape, it is pushed in (stretched) not only on the short side (short side: upper side and lower side in Fig. 1c) of the nest (3) but also on the long side (long side: left side and right side in Fig. 1c).

[0019] However, in Fig. 1c, beads (4a) are arranged on the long sides corresponding to the left and right sides, so that the amount pushed in by the beads (4a) (inflow amount: amount that the pouch sheet expands and enters the nest) is limited. Accordingly, a difference occurs between the inflow amount on the long side of the nest (3) and the inflow amount on the short side of the nest.

[0020] In particular, at the corners where the long and short sides intersect, wrinkles may occur due to differences in inflow, and in severe cases, breakage may occur.

[0021] Accordingly, a forming device for the pouch was required to prevent wrinkles and / or breaks that mainly occur at the corners where the long and short sides intersect.

[0022]

[0023] Therefore, the main purpose of the present invention is to provide a pouch forming device that can prevent wrinkles and / or breakage during forming of a pouch sheet.

[0024] More specifically, the present invention provides a forming device for a pouch capable of controlling the elongation of a pouch sheet (controlling the amount of inflow) by providing beads in which the distance between the nest and the bead is relatively farther in the area where the corner is formed, and the distance between the nest and the bead is relatively closer in the area where the distance from the corner is farther, in order to increase the amount of inflow near the corner where the cup portion is formed.

[0025]

[0026] In order to achieve the above-described purpose, a pouch forming device according to the present invention is a pouch forming device for forming a cup portion in a pouch sheet, comprising: a die having a nest formed in a concave fine shape on an upper surface and a flat portion formed along a perimeter of the nest; a stripper for pressing and fixing a portion of the pouch sheet placed on the flat portion when the pouch sheet is placed on the die; and a punch for pressing the pouch sheet so that it enters the nest and forming a cup portion in the pouch sheet; wherein a bead is formed protruding from a surface of the flat portion, and the bead is formed to form a curved shape on the flat portion.

[0027] The die has two long sides parallel to each other and two short sides parallel to each other and connecting the two long sides at the boundary between the nest and the flat portion, the flat portion includes a first region extending along the long side; and a second region extending along the short side, and the bead is formed in the first region.

[0028] Within the first region, the shortest distance between the bead and the long side is formed the furthest at both ends of the bead and the closest at the middle of the bead.

[0029] The above beads are formed in each of the first regions on both sides of the nest. At this time, the beads are formed symmetrically in each of the first regions on both sides.

[0030] A sub-bead may (optionally) be formed protrudingly on the surface of the second region. At this time, the shortest distance between the sub-bead and the short side within the second region is formed farthest from the ends of the sub-bead and closest from the middle of the sub-bead.

[0031] The above sub-beads are formed in each of the second regions on both sides with the nest in between.

[0032] The above sub-beads are formed symmetrically to each other in each of the second regions on both sides.

[0033] And, the nest is divided into two divided nests by a partition, and the partition is formed in a direction parallel to the long side.

[0034] In addition, sub-beads are formed protrudingly on the surface of the second region, and two sub-beads are formed in each of the second regions on both sides so as to place each split nest therebetween.

[0035]

[0036] The present invention having the above configuration is such that the bead is formed in a curved shape, and the shortest distance between the bead and the long side within the first region is formed closest at the middle of the bead and furthest at both ends of the bead, thereby preventing wrinkles and / or breakage of the pouch sheet that mainly occur near the edges of the nest.

[0037] That is, in the present invention, by increasing the amount of pouch sheet flowing in the vicinity of the nest edge (when the punch is lowered) and reducing the amount flowing in the middle area between the long side and the short side (by reducing the difference in the amount flowing in the middle area and the corner area when forming the cup part), wrinkles and / or breakage can be prevented.

[0038] The above beads are arranged symmetrically on both sides based on the above nest so that the inflow amount on both sides can be adjusted equally.

[0039] In addition, sub-beads can be additionally protruded on the surface of the second region to further increase the inflow near the corners.

[0040] In addition, the curl problem, which is a phenomenon in which the pouch film is partially rolled up due to internal stress remaining after the forming process, can be resolved or minimized.

[0041]

[0042] Figure 1a is a drawing showing a pouch sheet inserted into a conventional pouch forming device.

[0043] Fig. 1b is a drawing showing the state in which the punch is lowered while the stripper is lowered and the pouch sheet is fixed in the state in Fig. 1a.

[0044] Figure 1c is a drawing showing a conventional die viewed from above.

[0045] FIG. 2 is a drawing showing a die provided in the first embodiment of the present invention viewed from above.

[0046] Figure 3 is a drawing showing a sub-bead additionally formed in the die shown in Figure 2.

[0047] FIG. 4 is a drawing showing a die provided in a second embodiment of the present invention viewed from above.

[0048] Figure 5 is a drawing showing the appearance of additional sub-beads formed in the die shown in Figure 4.

[0049]

[0050] Hereinafter, the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0051] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0052] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0053] The present invention relates to a pouch forming device that can prevent the occurrence of wrinkles and / or breakage by increasing the amount of inflow into the nest during forming of a pouch sheet. Hereinafter, embodiments provided by the present invention will be described in more detail with reference to the attached drawings.

[0054]

[0055] First embodiment

[0056]

[0057] FIG. 2 is a drawing showing a die provided in the first embodiment of the present invention viewed from above, and FIG. 3 is a drawing showing a die shown in FIG. 2 with a sub-bead additionally formed.

[0058] Referring to FIGS. 2 and 3, the forming device of the pouch provided in this embodiment is a forming device that forms a cup portion (1a) in a pouch sheet (1), and includes a stripper, a punch, and a die (10), characterized in that the formed bead (13) of the die (10) is formed to have a curved shape.

[0059] The above die (10) is positioned so as to be placed under the pouch sheet and has a flat upper surface, but a nest (11) is formed in a concave fine shape in the center of the upper surface (corresponding to the size and area of ​​the cup portion to be formed in the pouch sheet). The portion of the upper surface excluding the nest (11), that is, the remaining portion excluding the nest (11) along the perimeter of the nest (11), forms a flat portion (12).

[0060] The above stripper is positioned to press and fix the portion of the pouch sheet (1) placed on the flat portion (12) when the pouch sheet (1) is placed on the die (10). The stripper is positioned so as to press the flat portions (12) on both sides with the punch in between. At this time, the stripper may have a concave groove (not shown) formed so that it can enter the interior in a manner that matches the shape of the bead (13) and the sub-bead (14) at a position corresponding to the bead (13) and the sub-bead (14).

[0061] The above punch is positioned above the die (10) and is configured to be able to rise and fall. When raised, it rises to a height that allows the pouch sheet (1) to enter between the die (10), and when lowered, it enters the nest (11) and presses and stretches the pouch sheet (1) against the surface of the nest (11), thereby forming a cup portion (1a) in the pouch sheet (1).

[0062] In addition, as described above, in this embodiment, a bead (13) is formed to protrude from the surface of the flat portion (12), and the bead (13) is formed to form a curved shape having a predetermined curvature on the flat portion (12).

[0063] The above die (10) is formed with two long sides (l) that are parallel to each other at the boundary between the nest (11) and the flat portion (12) and two short sides (s) that are parallel to each other and connect the two long sides (l).

[0064] That is, since the nest (11) is formed to have a rectangular shape when viewed from above as shown, the relatively longer side can be defined as the long side (l) and the relatively shorter side can be defined as the short side (s).

[0065] Accordingly, the flat portion (12) can be divided into a first region (a) extending along the long side (l) and a second region (b) extending along the short side (s). More specifically, the first region (a) means a rectangular region that includes the long side (l), which is the boundary between the nest (11) and the flat portion (12), as one of its two long sides. The other long side of the rectangular region is formed by a portion of the long side of the die. In addition, the second region (b) means a rectangular region that includes the short side, which is the boundary between the nest (11) and the flat portion (12), as one of its two short sides. The other long side of the rectangular region is formed by a portion of the short side of the die.

[0066] In this embodiment, the bead (13) is formed in the first region (a).

[0067] At this time, the shortest distance (straight line distance along the left-right direction based on FIG. 2) between the bead (13) and the long side (l) within the first region (a) is formed farthest (w) from both ends of the bead (13) and closest (x) from the middle of the bead (13).

[0068] That is, the beads (13) are arranged so that the ends facing the edges of the nest (11) are furthest (w) so that the inflow can increase near the edges of the nest (11) (so that the area that can be stretched in the pouch sheet becomes wider). Conversely, the middle part of the nest (11) is formed so that the shortest distance between it and the long side (l) is closest (x) so that the inflow can be reduced because the pouch sheet is relatively less stretched when the punch is lowered.

[0069] In addition, the beads (13) are formed in each of the first regions (a) on both sides of the nest (11). And, the beads (13) are formed to be symmetrical to each other in each of the first regions (a) on both sides.

[0070] And, as shown in FIG. 3, a sub-bead (14) can be selectively formed to protrude on the surface of the second region (b) so as to further increase the inflow toward the edge of the nest (11).

[0071] For the same reason as the bead (13), the shortest distance between the sub-bead (14) and the short side (s) within the second region (b) is formed farthest (w) at both ends of the sub-bead (14) and closest (v) at the middle of the sub-bead (14).

[0072] And, the sub-beads (14) are formed in each of the second regions (b) on both sides with the nest (11) in between. In addition, the sub-beads (14) are also formed to be symmetrical to each other in each of the second regions (b) on both sides.

[0073]

[0074] Second embodiment

[0075]

[0076] FIG. 4 is a drawing showing a die provided in a second embodiment of the present invention viewed from above, and FIG. 5 is a drawing showing a die shown in FIG. 4 in which sub-beads are additionally formed.

[0077] The nest provided in this embodiment is divided into two split nests (11a, 11b) by a partition (15), and the partition (15) is formed in a direction parallel to the long side (l).

[0078] In this embodiment, as in the first embodiment, a stripper and a punch are provided.

[0079] The above stripper descends when the pouch sheet is placed on the die (10) and presses the portion placed on the flat portion (12). In addition, a concave groove can be formed at a position corresponding to the bead (13) and sub-bead so that it can enter the interior according to the shape of the bead and sub-bead.

[0080] The punch is positioned above the die (10) and is configured to be able to rise and fall. When raised, it rises to a height that allows the pouch sheet (1) to enter between the die (10), and when lowered, it enters each of the divided nests (11a, 11b) and presses the pouch sheet against the surface of the divided nest (11a, 11b), thereby forming a cup portion in the pouch sheet. The lower end of the punch provided in this embodiment has a shape that allows it to enter each of the divided nests (11a, 11b) when lowered, and is configured so as not to interfere with the partition (15).

[0081] The above-mentioned split nest is arranged to be placed under the pouch sheet and has a flat upper surface, but split nests (11a, 11b) are formed in a concave fine shape in the center of the upper surface (so that two cup portions to be formed in the pouch sheet can be formed), and the remaining portion except for the split nests (11a, 11b) and the partition portion (15) forms a flat portion (12).

[0082] The above-mentioned split nests (11a, 11b) are divided by a partition (15), and the partition (15) is formed to have the same height as or slightly lower than the flat portion (12) of the die (10) (to have a slightly fine shape).

[0083] In this embodiment, a bead (13) is formed protruding from the surface of the flat portion (12) (more specifically, from the first region), and the bead (13) is formed to have a curved shape with a predetermined curvature on the flat portion (12).

[0084] And, as in the structure of the first embodiment, the bead (13) is formed so that the shortest distance between the long side (l) and the first region (a) is furthest at both ends (w) and closest at the middle (x).

[0085] In addition, the above beads (13) are formed in each of the first regions (a) on both sides of the split nests (11a, 11b) and are formed to be symmetrical to each other in each of the first regions (a) on both sides.

[0086] And, as illustrated in FIG. 5, sub-beads (14a, 14b) may be selectively formed to protrude on the surface of the second region (b) so as to further increase the inflow toward the corners of each of the split nests (11a, 11b). The sub-beads (14a, 14b) are arranged to be located at the short sides (n) of each of the split nests (11a, 11b). That is, two of the sub-beads (14a, 14b) are formed in each of the second regions (b) on both sides so as to place each of the split nests (11a, 11b) between them.

[0087]

[0088] The present invention, having the above-described technical features, can eliminate the inflow resistance occurring near the corners of the nest (11) intersecting in the longitudinal and transverse directions by having a straight bead (13). That is, in the conventional structure, the pouch sheet along the perimeter of the nest (11) may have wrinkles due to differences in the amount of elongation at each point.

[0089] However, the present invention having the above configuration is formed with the bead (13) formed in a curved shape, and the shortest distance between the bead (13) and the long side within the first region (a) is formed closest at the middle of the bead and furthest at both ends of the bead, thereby preventing wrinkles and / or breakage of the pouch sheet that mainly occur near the corners of the nest (11).

[0090] That is, in the present invention, by increasing the amount of inflow of the pouch sheet (1) near the edge of the nest (when the punch is lowered) and reducing the amount of inflow in the middle area between the long side and the short side (by reducing the difference in inflow amount between the edge area and the middle area when forming the cup part), wrinkles and / or breakage can be prevented.

[0091] The above beads (13) are arranged symmetrically on both sides based on the nest so that the inflow amount on both sides can be adjusted equally.

[0092] In addition, sub-beads (14: 14a, 14b) can be additionally protruded on the surface of the second region to further increase the inflow near the corner.

[0093] In addition, the curl problem, which is a phenomenon in which the pouch film is partially rolled up due to internal stress remaining after the forming process, can be resolved or minimized.

[0094] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0095]

[0096] [Explanation of symbols]

[0097] 10: Die

[0098] 11: Nest

[0099] 12: Flat area

[0100] 13: Bead

[0101] 14: Subvid

[0102] 15: Section

Claims

1. As a pouch forming device that forms a cup portion in a pouch sheet, A die having a concave, fine-shaped nest formed on the upper surface and a flat portion formed along the perimeter of the nest; A stripper that presses and fixes a portion of the pouch sheet placed on a flat surface when the pouch sheet is placed on the die; and A punch is included to form a cup portion in the pouch sheet by pressing the pouch sheet so that the pouch sheet enters the nest; A pouch forming device in which a bead is formed protruding from the surface of the above-mentioned flat portion, and the bead is formed to form a curved shape on the above-mentioned flat portion.

2. In paragraph 1, The above die is formed with two long sides parallel to each other at the boundary between the nest and the flat part and two short sides parallel to each other and connecting the two long sides, The above flat part is, A first region extending along the long side; and Including a second region extending along the above short side, The above bead is a forming device of a pouch formed in the first region.

3. In paragraph 2, A pouch forming device in which the shortest distance between the bead and the long side within the first region is furthest from both ends of the bead and closest from the middle of the bead.

4. In paragraph 3, The above beads are forming devices for pouches formed in each of the first regions on both sides of the nest.

5. In paragraph 4, The above beads are a forming device of a pouch formed symmetrically in each of the first regions on both sides.

6. In any one of paragraphs 2 to 5, A pouch forming device in which a sub-bead is formed protruding on the surface of the second region.

7. In paragraph 6, A pouch forming device in which the shortest distance between the sub-bead and the short side within the second region is furthest from both ends of the sub-bead and closest from the middle of the sub-bead.

8. In paragraph 7, The above sub-bead is a forming device for a pouch formed in each of the second regions on both sides with the nest in between.

9. In paragraph 8, The above sub-bead is a pouch forming device formed to be symmetrical to each other in each of the second regions on both sides.

10. In paragraph 2, The above nest is divided into two split nests by a partition, and the partition is a pouch forming device formed in a direction parallel to the long side.

11. In paragraph 10, A sub-bead is formed protruding on the surface of the second region, The above sub-bead is a pouch forming device formed in two portions in each of the second regions on both sides so as to place each split nest therebetween.

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