Pouch forming device for secondary batteries and method for manufacturing pouch-type secondary batteries using the same

Abstract

The present invention relates to a method for manufacturing a pouch-type secondary battery, and more specifically to a pouch-forming device capable of preventing curling and a method for manufacturing a secondary battery using the same. According to one embodiment of the present invention, there may be provided a pouch forming device for a secondary battery, including: a grip module that grips and fixes an edge of the pouch film; a first press module that is disposed on one side of the pouch film and presses and forms the pouch film in the other direction so as to stretch the pouch film; and a second press module that is disposed on the other side of the pouch film and presses and forms the pouch film in the one direction so as to form a battery cell receiving portion that has a step relative to the edge.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a pouch-type secondary battery, and more particularly to a pouch forming apparatus capable of preventing curling and a method for manufacturing a secondary battery using the same. [Background technology]

[0002] A secondary battery can be repeatedly used through a discharge process, which converts chemical energy into electrical energy, and a charge process, which converts electrical energy into chemical energy.

[0003] The secondary battery may include a nickel-cadmium (Ni-Cd) battery, a nickel-metal hydride (Ni-MH) battery, a lithium-metal battery, a lithium-ion (Li-Ion) battery, and a lithium-ion polymer battery (Li-Ion Polymer Battery, hereinafter referred to as "LIPB"), etc.

[0004] Lithium secondary batteries have a cycle life of more than 500 times and a short charging time of about 1 to 2 hours. They are about 30 to 40% lighter than nickel-metal hydride batteries, allowing for weight reduction. They also have the highest voltage per unit cell (30V to 37V) of all currently available secondary batteries, excellent energy density, and other characteristics optimized for mobile devices.

[0005] The lithium secondary battery may be manufactured as a pouch-type secondary battery by sealing the battery cell in a pouch made of an aluminum sealing material.

[0006] Generally, unit cells stacked in a three-layer structure of positive electrode / separator / negative electrode, or a five-layer structure of positive electrode / separator / negative electrode / separator / positive electrode or negative electrode / separator / positive electrode / separator / negative electrode are assembled to form a single electrode assembly. This electrode assembly is then housed in a pouch case, which acts as a sealant. Pouch type batteries house the electrode assembly in a pouch made of a flexible polymer material with an irregular shape.

[0007] The pouch, which is the case of a pouch-type secondary battery, is manufactured by forming a cup-shaped battery cell receiving portion that receives an electrode assembly in a pouch film made of a ductile material. That is, after the battery cell receiving portion having a receiving space for receiving the electrode assembly is formed in the pouch film, the electrode assembly is placed in the receiving space of the battery cell receiving portion, and the edge 10b2 is sealed to manufacture the secondary battery. Such a pouch film is composed of multiple layers, including an outer coating layer, a metal barrier layer, and an inner adhesive layer.

[0008] 1, an electrode assembly 50 is accommodated in a battery cell accommodating portion 10b1 formed in a lower pouch film 10b. The electrode assembly 50 has leads 51 and 52, and the leads are divided into a positive electrode lead 51 and a negative electrode lead 52. With the electrode assembly 50 accommodated in the battery cell accommodating portion 10b1, the edges 10b2 of the upper pouch film 10a and the lower pouch film 10b are sealed to manufacture a pouch-type secondary battery 20.

[0009] Recently, a commonly used method for manufacturing a pouch-type secondary battery is to form two cell receiving portions in one pouch film, place a cell in one of the cell receiving portions, stack the cells, and then seal the resulting structure. That is, the upper and lower pouch films may be connected and stacked without being separated.

[0010] 2 shows a plan view of the pouch film before molding. A battery cell receiving portion 10b1 was formed in the center of the lower pouch film 10b using a drawing molding method. Then, the electrode assembly 50 was placed in the battery cell receiving portion 10b1, and the edges 10b2 of the upper pouch film 10a and the lower pouch film 10b were sealed to form the pouch 10.

[0011] The drawing molding method was performed by fixing pouch films 10 a and 10 b to a fixing member 11 and stretching the fixed pouch films 10 a and 10 b with a punch member 12 .

[0012] Korean Patent Publication No. 10-2022-0053414 (hereinafter referred to as the "Prior Patent") discloses a battery case molding device and a battery case manufacturing method that pressurize a laminate sheet of a pouch to form a battery case. In particular, it discloses a technology for expanding the stretching section of the laminate sheet to prevent localized excessive stretching of the laminate sheet.

[0013] However, the prior patent does not recognize the problem that when pressurizing the pouch film from top to bottom during the drawing and molding process of the laminate sheet to form the battery cell accommodating section, the pressure applied to the pouch film tends to concentrate on specific parts, such as the corners of the cup shape, and excessive stretching is likely to occur at the corners of the battery cell accommodating section.

[0014] In other words, the corners of the battery cell housing in the prior art are areas that are subject to severe deformation due to structural breaks during shaping, and the difference in elongation rate between the outer and inner surfaces becomes apparent, which can make the corners fragile.

[0015] As a result, the prior patents were unable to solve problems such as excessive stretching of the corners, which spoiled the appearance of the pouch secondary battery, or the corners being thin and fragile, which shortened the lifespan of the pouch.

[0016] Furthermore, in the conventional drawing-molding process, when a punch member 12 presses the lower pouch film 10b from top to bottom to form a battery cell receiving portion, as shown in FIGS. 3 and 4, differences in the elongation rates of the layers making up the pouch film may occur.

[0017] When processing the shape of the pouch film's battery cell receiving portion, the difference in the accumulated stretch rate between the top and bottom surfaces of the pouch from the center to the edge of the pouch film can become noticeable at the edge. For example, when a pouch film is formed with a battery cell receiving portion that protrudes downward, the difference in the stretch rate between the bottom surface of the pouch film and the top surface of the pouch film can accumulate further at the edge, causing curling at the edge. As a result, in the conventional technology, the edge 10b2 of the pouch film 10b was curled up, as shown in Figure 5.

[0018] This curling phenomenon causes difficulties in subsequent processes such as the process of transporting the pouch film or the process of sealing or folding the edges of the pouch film, or it increases the likelihood of defects such as the edges of the pouch film being folded, or the edges being sealed while still folded, thereby increasing the rate of defects.

[0019] Therefore, it is necessary to provide a pouch forming device and a method for manufacturing a pouch-type secondary battery that can prevent excessive stretching from occurring at the corners of the battery cell accommodating portion of the conventional pouch film and reduce the edge curling phenomenon. Summary of the Invention [Problem to be solved by the invention]

[0020] An object of the present invention is to solve the problems associated with conventional manufacturing apparatuses and methods for pouch-type secondary batteries.

[0021] According to one embodiment of the present invention, there is provided a pouch forming device that can minimize the curling phenomenon in which the edges of a pouch film are bent into a round shape and prevent excessive stretching of the corners of a battery cell receiving portion, and a method for manufacturing a pouch-type secondary battery using the same.

[0022] According to one embodiment of the present invention, there is provided a pouch molding device that can pressurize an area of ​​a pouch film where a battery cell accommodating portion is to be formed primarily using a first press block having an ellipsoidal shape without increasing the variation in surface pressure, and a method for manufacturing a pouch-type secondary battery using the same. [Means for solving the problem]

[0023] To achieve the above-mentioned object, according to one embodiment of the present invention, there may be provided a pouch forming device for a secondary battery, including: a grip module that grips and fixes an edge of the pouch film; a first press module that is disposed on one side of the pouch film and presses and forms the pouch film in the other direction so as to stretch the pouch film; and a second press module that is disposed on the other side of the pouch film and presses and forms the pouch film in the one direction so as to form a battery cell receiving portion that is stepped relative to the edge.

[0024] The pouch film may be a pouch fabric if it is a unit pouch. The pouch fabric may be supplied to a molding device at one pitch, i.e., the length of a unit pouch, and then molded. The pouch fabric may then be cut into unit pouches. Of course, the pouch film may also be supplied to a molding device in a cut state and then molded.

[0025] The edge of the pouch film refers to the peripheral frame of the battery cell receiving portion, and the portion surrounded by the edge may be press-molded to be depressed.

[0026] In order to prevent a curling phenomenon in which the edges of the pouch film are bent into a round shape and to reduce the elongation rate of the corners of the battery cell accommodating portion, it is preferable that the press forming of the second press module is performed after the press forming of the first press module.

[0027] When the battery cell receiving portion is formed after pressure molding using only the second press module, a curling phenomenon may occur after pressure molding due to the difference in elongation rate between the upper and lower surfaces of the pouch film. For example, because the elongation rate of the lower surface is greater than that of the upper surface, additional deformation, i.e., curling, may occur to compensate for the difference in elongation rate after pressure molding.

[0028] Therefore, the difference in stretch ratio between the top and bottom surfaces of the pouch film can be reduced by performing the pressure forming process in the first press module in the reverse direction before performing the pressure forming process in the second press module. For example, the pressure forming process in the first press module can be performed so that the stretch ratio of the top surface of the pouch film is greater than the stretch ratio of the bottom surface. Then, the pressure forming process in the opposite direction in the second press module can be performed to reduce the difference in stretch ratio between the bottom surface and the top surface.

[0029] The grip module preferably includes a film die having a die opening that opens in the vertical direction and that pressurizes and supports the lower surface of the pouch film when the pouch is pressurized, and a stripper having a stripper opening that corresponds to the die opening and that pressurizes and supports the upper surface of the pouch film when the pouch is pressurized.

[0030] The die opening and the stripper opening are preferably formed to correspond to the shape of the battery cell receiving portion.

[0031] The first press module may include a first press block that is inserted sequentially into the die opening and the stripper opening along a first axial direction perpendicular to the pouch film, and the second press module may include a second press block that is inserted sequentially into the stripper opening and the die opening along the first axial direction perpendicular to the pouch film.

[0032] The first press block and the second press block are also called punches.

[0033] The second press block preferably has a shape corresponding to the battery cell receiving portion.

[0034] The first press block may be smaller than the second press block. The pressing area and punching depth of the first press block may be smaller than the pressing area and punching depth of the second press block. That is, the amount of primary deformation may be smaller than the amount of secondary deformation, and the tension applied to the pouch film may be gradually increased to stably form the final battery cell receiving portion.

[0035] The first press block may have an ellipsoid shape, and the second press block may have a shape corresponding to the battery cell receiving portion.

[0036] The first press module may include a first press platform having a first rest groove formed therein in which the first press block is received, and the first press block may be configured to be raised and lowered relative to the first press platform.

[0037] The first press platform and the first press block may be configured to move up and down integrally, and the first press block may be configured to move up and down relative to the first press platform.

[0038] The second press module may include a second press platform having a second stationary groove formed therein for receiving the second press block, and the second press block may be configured to be raised and lowered relative to the second press platform. The second press platform may be fixed, and the second press block may be configured to be raised and lowered relative to the second press platform.

[0039] When the second press block presses and forms the pouch film, the first press block and the first press platform may support one side of the second press block to generate a repulsive force against the pressing force of the second press block, i.e., the first press platform may function as a stopper.

[0040] To achieve the above-mentioned object, according to one embodiment of the present invention, there is provided a method for manufacturing a pouch-type secondary battery using a pouch forming device including a gripping module, a first press module, and a second press module, the method including: a gripping step in which the gripping module grips and fixes an edge of a pouch film; a first press step in which the first press module, arranged on one side of the pouch film, presses the pouch film in the other direction to stretch the pouch film; and a second press step in which the second press module, arranged on the other side of the pouch film, presses the pouch film in the one direction to form a battery cell receiving portion that is stepped relative to the edge.

[0041] In order to prevent a curling phenomenon in which the edge of the pouch film is bent into a round shape and to reduce an elongation rate of the corners of the battery cell receiving portion, it is preferable that the second pressing step be performed after the first pressing step is completed.

[0042] The gripping module may include a film die having a die opening formed therein, and a stripper having a stripper opening formed therein that corresponds to the die opening.

[0043] The gripping step may include raising the film die to pressurize and fix the pouch film between the film die and a stripper.

[0044] The film die may be configured to rise together with the first press module, i.e., a gripping step may be performed in which the pouch film is fixed using the pressure of the first press module.

[0045] The first press module includes a first press platform and a first press block, and the first press block can be raised and lowered relative to the first press platform during the first press step. That is, the first press block is raised to perform the first press, and then the first press block is lowered and returned to its original position to complete the first press.

[0046] In the first pressing step, the first press block is preferably inserted into the die opening and the stripper opening in that order.

[0047] The second press step is preferably performed after the first press block returns to its original position. Of course, it is preferable that the gripping step of the pouch film is still maintained after the first press step is completed. This gripping step is preferably maintained until the subsequent second press step is completed.

[0048] Preferably, the second press module includes a second press platform and a second press block, and in the second pressing stage, the second press block is inserted into the stripper opening and the die opening sequentially.

[0049] The second press block may have a shape corresponding to the battery cell receiving portion and may be relatively larger in size than the first press block. For example, the second press step may have a larger pressing depth and pressing area than the first press step.

[0050] In the second pressing step, the second press block may be raised and lowered relative to the second press platform, or the second pressing step may be performed by raising the first press module and the grip module as a whole and lowering the second press block relative to the first press module. [Effects of the Invention]

[0051] According to one embodiment of the present invention, there is provided a pouch forming device that can minimize the curling phenomenon in which the edges of a pouch film are bent into a round shape and prevent excessive stretching of the corners of a battery cell receiving portion, and a method for manufacturing a pouch-type secondary battery using the same.

[0052] According to one embodiment of the present invention, a pouch molding device is provided in which a first press block having an ellipsoidal shape can pressurize a pouch film without causing large variations in surface pressure, and which can prevent excessive stretching of the corners of a battery cell accommodating section, and a method for manufacturing a pouch-type secondary battery using the same is provided.

[0053] According to an embodiment of the present invention, the difference in elongation rate between the inner and outer surfaces of the pouch film can be reduced, and the curling phenomenon of the pouch film at the outer periphery of the battery receiving portion can be effectively prevented.

[0054] According to an embodiment of the present invention, the difference in elongation rate between the inner and outer surfaces of the pouch film can be reduced, thereby enabling efficient formation of the battery housing portion. In particular, the recovery rate at the corners of the battery housing portion can be effectively reduced. [Brief explanation of the drawings]

[0055] [Figure 1] FIG. 1 is a perspective view of a pouch-type secondary battery according to the prior art. [Figure 2] FIG. 1 is a plan view of a pouch film before molding of a pouch-type secondary battery according to the prior art. [Figure 3] 1 is a vertical cross-sectional view showing a molding process of a pouch molding device of the prior art. [Figure 4] 1 is a vertical cross-sectional view showing a molding process of a pouch molding device of the prior art. [Figure 5] 1 is a vertical cross-sectional view of a pouch film formed using a prior art pouch forming apparatus. [Figure 6] 1A-1C are separated perspective views of several configurations of a pouch forming apparatus according to one embodiment of the present invention. [Figure 7] 1 is a side cross-sectional view of a pouch forming apparatus according to one embodiment of the present invention. [Figure 8] 1 is a side cross-sectional view of a pouch forming apparatus according to one embodiment of the present invention. [Figure 9] 1 is a side cross-sectional view of a pouch forming apparatus according to one embodiment of the present invention. [Figure 10] 1 is a side cross-sectional view of a pouch forming apparatus according to one embodiment of the present invention. [Figure 11] 10 is a vertical cross-sectional view of a pouch forming apparatus according to another embodiment of the present invention. [Figure 12] 1 is a conceptual diagram of a pouch forming apparatus according to one embodiment of the present invention. [Figure 13] 1 is a vertical cross-sectional view of a pouch film formed using a pouch forming apparatus according to an embodiment of the present invention. [Figure 14] 10A-10C are exploded perspective views of several configurations of a pouch forming apparatus according to another embodiment of the present invention. [Figure 15] 10 is a cross-sectional view of a pouch forming apparatus according to yet another embodiment of the present invention. [Figure 16] 2 is a flowchart of a method for manufacturing a pouch-type secondary battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0056] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pouch forming apparatus according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0057] First, the pouch forming apparatus 100 will be described with reference to Figures 6 to 13. Specifically, the pouch forming apparatus 100 according to one embodiment of the present invention is configured to form a pouch film 10b for a pouch-type secondary battery. To this end, the pouch forming apparatus 100 of the present invention includes a grip module 110, a first press module 120, and a second press module 130.

[0058] The grip module 110 is configured to grip and fix the edge 10b2 of the pouch film 10b. When the pouch film 10b is rectangular in shape, the grip module 110 may be configured to hold the edge 10b2 of the rectangular pouch film 10b to fix the pouch film 10b. That is, the grip module 110 can fix the edge 10b2 of the pouch film 10b.

[0059] The grip module 110 may include a die 112 that supports the lower surface of the pouch film 10b and a stripper 114 that supports the upper surface. After the pouch film 10b is placed between the die 112 and the stripper 114, the die 112 may be raised to pressurize and fix the pouch film 10b between the die 112 and the stripper 114.

[0060] The first press module 120 may be arranged on one side of the pouch film 10b. For example, the first press module 120 may be arranged below the pouch film 10b. The first press module 120 may also be configured to stretch the pouch film 10b. The first press module 120 may also be configured to pressurize and mold the pouch film 10b in the other direction. That is, the first press module 120 may press the pouch film 10b in the other direction until it is stretched at a predetermined stretch rate.

[0061] 8, when the first press module 120 is disposed below the pouch film 10b, the first press module 120 may be configured to press-form the pouch film 10b in the upward direction (Z-axis direction). The portion of the pouch film 10b where the battery cell accommodating portion 10b1 is formed by the first press module 120 may be deformed to protrude upward.

[0062] The second press module 130 may be disposed on the other side of the pouch film 10b. For example, the second press module 130 may be disposed above the pouch film 10b. The second press module 130 may also be configured to press-form the pouch film 10b in one direction to form a battery cell receiving portion 10b1 that is stepped relative to the edge 10b2. That is, the second press module 130 presses the pouch film 10b in the direction opposite to the pressing direction of the first press module 120, thereby effectively reducing the difference in elongation rate of the layers constituting the pouch film 10b. Therefore, as shown in FIG. 13 , the edge 10b2 of the pouch film 10b on which the battery cell receiving portion 10b1 has been formed by the pouch forming apparatus 100 of the present invention does not curl and maintains a flat shape.

[0063] 9, the second press module 130 may be configured to press-form the pouch film 10b downward at the portion that protrudes and deforms upward. In this case, the portion of the pouch film 10b where the battery cell receiving portion 10b1 is to be formed may be stretched downward. That is, the second press module 130 may perform a second press-forming on the pouch film 10b to form the battery cell receiving portion 10b1 in the remaining portion of the pouch film 10b excluding the edge portion 10b2.

[0064] The second pressing module 130 may have various shapes depending on the shape of the battery cell accommodating portion 10b1 of the pouch in which the electrode assembly (not shown) is accommodated. As an example, the internal space of the battery cell accommodating portion 10b1 of the pouch may have a flat hexahedron shape. However, the battery cell accommodating portion 10b1 is not necessarily limited to this shape and may have various shapes.

[0065] According to one embodiment of the present invention, the pouch film 10b is subjected to a first pressure molding using the first press module 120 so that the stretch rate of the upper surface is greater than that of the lower surface, and then a second pressure molding is performed by pressing the pouch film 10b in the opposite direction using the second press module 130. However, since the upper surface of the pouch film 10b is already stretched, even if the lower surface stretches, the difference in the stretch rate between the upper and lower surfaces will ultimately be small.

[0066] Therefore, the pouch forming apparatus 100 of the present invention can minimize the curling phenomenon in which the edge 10b2 of the pouch film 10b is rounded by using the first press module 120 and the second press module 130 that press in opposite directions to form the battery cell receiving portion 10b1 of the pouch, and can prevent excessive stretching of the corners of the battery cell receiving portion 10b1 by stretching the pouch film 10b in two stages using the first press module 120 and the second press module 130. Here, the corners may be, for example, corners connecting the side walls to the bottom of the battery cell receiving portion 10b1 and corners connecting one side wall to the other side wall.

[0067] 12, the pouch forming apparatus 100 of the present invention may further include a control unit 140. The control unit 140 may control the first press module 120 and the second press module 130 to prevent a curling phenomenon in which the edge 10b2 of the pouch film 10b is bent into a round shape, and to reduce the stretch rate of the corners of the battery cell receiving portion 10b1.

[0068] For example, as shown in Figures 7 to 10, the control unit 140 can control the first press module 120 and the second press module 130 so that the first press module 120 performs pressure molding in an upward direction, and then the second press module 130 performs pressure molding in a downward direction.

[0069] More specifically, the first press module 120 may include a first press block 122 that is movable up and down along a first axis direction perpendicular to the pouch film 10b, and a first press platform 124 that has a first mounting groove 134a formed therein and that accommodates the first press block 122. Here, the first axis direction refers to the vertical direction (Z-axis direction) relative to the ground. For example, the first press block 122 may be accommodated in the first mounting groove 134a of the first press platform 124 and configured to be movable upward in the first axis direction to press the pouch film 10b. The pouch forming apparatus 100 of the present invention may also include a moving member (not shown in FIGS. 7 to 10 ) configured to move the first press block 122 and the second press block 132. The first press block 122 and the second press block 132 move at a constant pressure and speed, and can apply pressure to one side or the other of the pouch film 10b seated on the film die 112 to stretch the pouch film 10b.

[0070] The second press module 130 may include a second press block 132 that is provided so as to be movable up and down along a first axial direction perpendicular to the pouch film 10b, and a second press platform 134 that has a second rest groove 134a formed therein and that accommodates the second press block 132. For example, the second press block 132 may be accommodated in the second rest groove 134a of the second press platform 134 and be provided so as to be movable downward in the first axial direction (negative (-) direction of the Z axis) to press the pouch film 10b.

[0071] Furthermore, the second press block 132 may have a shape corresponding to the internal space of the battery cell receiving portion 10b1 of the pouch film 10b. The second press block 132 may be relatively larger in size than the first press block 122. Because the battery cell receiving portion 10b1 is formed in the pouch film 10b using the second press block 132, it is preferable that the portion where the battery cell receiving portion 10b1 is formed be stretched by the second press block 132 to a greater extent than the first press block 122. Conversely, if the second press block 132 is smaller in size than the first press block 122, sufficient stretching may not occur in the pouch film 10b to form the battery cell receiving portion 10b1, which is not preferable.

[0072] Therefore, in the first press module 120 and the second press module 130 of the present invention, the first press block 122 and the second press block 132 stretch the pouch film 10b in two stages, and the second press block 132, which is relatively larger than the first press block 122, forms the battery cell accommodating portion 10b1. As a result, as shown in FIG. 13, excessive stretching does not occur at the corners of the battery cell accommodating portion 10b1, and a battery cell accommodating portion 10b1 with a perfect shape can be formed.

[0073] FIG. 14 is an exploded perspective view of a pouch forming apparatus according to another embodiment of the present invention.

[0074] 14, the first press block 122A of the pouch forming apparatus 100 according to another embodiment of the present invention may have a different shape and size from the second press block 132. For example, the first press block 122A may have a spherical or ellipsoid shape. Unlike the rectangular parallelepiped first press block 122 of FIG. 6, the first press block 122A has a curved surface, which makes it possible to apply pressure to the portion of the pouch film 10b where the battery cell receiving portion 10b1 is to be formed without causing a large deviation in surface pressure.

[0075] Meanwhile, the second press block 132 may have a shape corresponding to the battery cell accommodating portion 10b1. For example, if the internal space of the battery cell accommodating portion 10b1 has a hexahedral shape, the second press block 132 may have a hexahedral shape of a size corresponding to the hexahedral shape.

[0076] Therefore, a pouch forming apparatus 100 according to another embodiment of the present invention includes a first press block 122A having a spherical or ellipsoid shape and a second press block 132 having a shape corresponding to the internal space of the battery cell accommodating portion 10b1, and thus the first press block 122A having a spherical or ellipsoid shape can press-form the portion of the pouch film 10b where the battery cell accommodating portion 10b1 is to be formed in a primary process without significant variations in surface pressure, thereby allowing uniform stretching to occur in the portion of the pouch film 10b where the battery cell accommodating portion 10b1 is to be formed. As a result, excessive stretching can be effectively prevented from occurring at the corners of the battery cell accommodating portion 10b1 during the secondary press-forming process by the second press block 132.

[0077] 7 to 13, the grip module 110 of the pouch forming apparatus 100 according to an embodiment of the present invention may include a film die 112 and a stripper 114. Specifically, the film die 112 may have a die opening 112a in a block body that opens in a first axial direction. The die opening 112a may have a size that allows a first press block 122 to pass through. The first press block 122 may be configured to pressurize the pouch film 10b by being inserted into the die opening 112a in an upward direction in the first axial direction (the Z-axis direction in FIG. 6). The first press block 122 may pass through the die opening 112a. For example, the film die 112 may be configured to be movable up and down along the first axial direction by a moving member (not shown) such as a pneumatic cylinder. For example, the pneumatic cylinder may be configured as a so-called hydraulic system that operates through pressure generated by the flow of a fluid such as gas or liquid inside. Therefore, the first press block 122 can pressurize the pouch film 10b while passing through the die opening 112a, allowing for a precise stretching process.

[0078] The stripper 114 may also have a stripper opening 114a that opens upward and downward in the block body. The stripper opening 114a may have a size that allows the second press block 132 to pass through. The stripper 114 may be provided so as to be movable up and down along the first axial direction. For example, the stripper 114 may be provided so as to be movable up and down along the first axial direction by a moving member (not shown) such as a pneumatic cylinder. A portion of the stripper 114 may be connected to the pneumatic cylinder. The stripper 114 may be provided so as to pressurize one surface (top surface) of the film die 112 with the pouch film 10b placed on the film die 112 by the moving member.

[0079] The second press block 132 may be configured to pressurize the pouch film 10b by being inserted into the stripper opening 114a downward in the first axial direction (the Z-axis direction in FIG. 6). The second press block 132 may pass through the stripper opening 114a. That is, the second press block 132 can pressurize the pouch film 10b while passing through the stripper opening 114a, enabling a precise stretching process.

[0080] Therefore, the pouch forming apparatus 100 of the present invention includes a film die 112 and a stripper 114, so that the edge 10b2 of the pouch film 10b can be stably fixed, and the stretching process of the pouch film 10b can be performed using the first press module 120 and the second press module 130 while precisely controlling the stretching ratio.

[0081] Referring to FIG. 12, in a pouch forming apparatus 100A according to another embodiment of the present invention, when the second press block 132 presses and forms the pouch film 10b, the first press block 122 and the first press platform 124 may be configured to block the lower surface of the second press block 132 to generate a repulsive force against the downward force of the second press block 132.

[0082] That is, the first press block 122 and the first press platform 124 may perform a press die function for the second press block 132 when the second press block 132 presses and forms the pouch film 10b. Here, the "press die function" refers to the function of applying a repulsive force to the lower surface of the second press block 132 against the downward force of the second press block 132 in order to form the shape of the battery cell accommodating portion 10b1.

[0083] In this case, the first press block 122 and the first press platform 124 may be positioned higher than the first press block 122 and the first press platform 124 of FIG. 10 so as to block the underside of the block of the second press to perform the function of the press die.

[0084] 15, a pouch forming apparatus 100 according to another embodiment of the present invention may further include a cooling member 150. The cooling member 150 may be configured to cool at least one of the film die 112 and the stripper 114. For example, as shown in FIG. 15, a pouch forming apparatus 100 according to another embodiment of the present invention may further include two cooling members 150 configured to cool the film die 112 and the stripper 114, respectively. For example, the cooling members 150 may be in contact with the film die 112 and the stripper 114 to cool them by heat conduction. For example, the cooling members 150 may use a refrigerant to discharge heat generated in the film die 112 and the stripper 114 to the outside. For example, the refrigerant may be cooling water. The refrigerant may be configured to be movable inside the cooling member 150. Alternatively, the cooling member 150 may include a metal material with excellent thermal conductivity. For example, the cooling member 150 may include an aluminum or copper material.

[0085] Therefore, the pouch forming apparatus 100 according to another embodiment of the present invention further includes a cooling member 150, which can cool at least one of the film die 112 and the stripper 114, thereby cooling the frictional heat generated during the stretching process, reducing the stretching rate at the edge 10b2 of the pouch film 10b fixed by the film die 112 and the stripper 114, and minimizing unnecessary deformation of the edge 10b2 of the pouch film 10b, such as curling.

[0086] Hereinafter, a method for manufacturing a pouch-type secondary battery using the pouch-forming device 100 will be described with reference to FIG. 16 as well as FIGS.

[0087] A method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention is a method for manufacturing a pouch-type secondary battery using a pouch forming apparatus 100 including a grip module 110, a first press module 120, and a second press module 130.

[0088] Specifically, the method for manufacturing the pouch-type secondary battery of the present invention may include a fixing step S01, a first pressing step S20, and a second pressing step S30, as shown in FIG.

[0089] A pressure sufficient to finally form the battery cell accommodating portion in the pouch film is required. Such a pressure is determined taking into consideration not only the pressure required to form the battery cell accommodating portion but also the pressure required to fix the pouch film when forming the battery cell accommodating portion. This is because if the pouch film is not fixed with sufficient pressure, wrinkles may occur at the edge of the pouch film.

[0090] Therefore, essentially, the pressure of the first press module against the second press module 130 may be used to form the pouch.

[0091] Specifically, in the fixing step S01, the gripping module 110 grips and fixes the edge 10b2 of the pouch film 10b. That is, the gripping module 110 fixes the edge 10b2 of the pouch film 10b, so that the first pressing step and the second pressing step may be performed stably thereafter.

[0092] In the pouch fixing step S01, the first press module may generate a pressure while rising. At this time, the film die may also rise together, and the pressure may be transmitted to the stripper. Therefore, the pouch film may be pressed and fixed between the film die and the stripper by the rising pressure of the first press module.

[0093] In the first pressing step S02, a first press module 120 disposed on one side of the pouch film 10b presses the pouch film 10b toward the other side to stretch the pouch film 10b. For example, as shown in Fig. 8, the first press module 120 may be configured to press and mold the pouch film 10b in an upward direction (the positive (+) direction of the Z axis). The first press module 120 may deform a portion of the pouch film 10b where the battery cell receiving portion 10b1 is to be formed so as to protrude upward.

[0094] Specifically, the pouch film 10b may be press-formed while the first press block 122 of the first press module 120 is raised. That is, the first press block 122 may be raised alone with the pouch film in a fixed position and inserted sequentially into the opening of the die film and the opening of the stripper to perform the first press step. The first press step may then be completed when the first press block 122 returns to its original position. At this time, the pouch film remains fixed.

[0095] In the second-pressing step S03, a second press module 130 disposed on the other side of the pouch film 10b secondarily presses the pouch film 10b in one direction to form a stepped battery cell receiving portion 10b1 relative to the edge portion 10b2. For example, as shown in FIGS. 9 and 10 , the second press module 130 may be configured to press and form the pouch film 10b downward at the portion that is deformed to have a convex shape upward. In this case, the portion of the pouch film 10b where the battery cell receiving portion 10b1 is to be formed may be stretched downward. The second press module 130 may secondarily press the pouch film 10b to form the battery cell receiving portion 10b1 in the remaining portion of the pouch film 10b excluding the edge portion 10b2.

[0096] Specifically, after the first pressing step is completed, the first press module 120 may provide a pressure while rising together with the grip module 110. That is, the grip module 110 may rise together with the first press module 120 while the pouch film is still pressed and fixed in the grip module 110. At this time, the pressure may be generated by the rising pressure of the first press module 120.

[0097] In one embodiment, the second press stage may be performed by raising and lowering the second press block 132 of the second press module 130. In this case, a very large press force, i.e., the press force generated by raising the first press module 120, cannot be used in the second press stage. According to this embodiment, the drive of the grip module and the drive of the first press module may be performed by a single drive. However, a drive of the first press block and a drive of the second press block may also be added, so that pouch molding can be performed using a total of three drives.

[0098] In another embodiment, the second press step may be performed by raising the grip module 110 and the first press module 120 while the second press block 132 remains relatively fixed. That is, the second press step may be performed by raising the first press module 120 and the grip module 110, so that the second press block 132 is inserted sequentially into the opening of the stripper and the opening of the film die. In this case, a very large press force, i.e., the press force generated by the raising of the first press module 120, can be used in the second press step. Meanwhile, according to this embodiment, the drive of the grip module and the drive of the first press module may be performed by a single drive. However, a pouch may be formed using two drives in total by adding the drive of the first press block.

[0099] Therefore, the method for manufacturing a pouch-type secondary battery of the present invention includes the first pressing step S02 and the second pressing step S03, thereby minimizing the curling phenomenon in which the edge 10b2 of the pouch film 10b is bent into a round shape, and since the first pressing module 120 and the second pressing module 130 stretch the pouch film 10b in two stages to form the battery cell receiving portion 10b1, excessive stretching of the corners of the battery cell receiving portion 10b1 can be prevented.

[0100] In particular, the pressure required for the first press step may be smaller than the pressure required for the second press step. That is, the press depth and / or press area may be relatively smaller in the first press step. Therefore, for the first press, it is easy to implement the first press module 120 with the first press block 122 moving up and down relative to the first press platform 124.

[0101] In the method for manufacturing a pouch-type secondary battery of the present invention, the pouch forming apparatus 100 may be implemented by a control unit 140. The control unit 140 may control the first pressing step S02 and the second pressing step S03 to be performed sequentially. For example, as shown in FIG. 9, the control unit 140 may control the first pressing module 120 and the second pressing module 130 to perform pressure forming in an upward direction, and then the second pressing module 130 to perform pressure forming in a downward direction. As a result, the method for manufacturing a pouch-type secondary battery of the present invention may prevent a curling phenomenon in which the edge 10b2 of the pouch film 10b is bent into a round shape, and may reduce the elongation rate of the corners of the battery cell receiving portion 10b1.

[0102] In the method for manufacturing a pouch-type secondary battery of the present invention, the first press module 120 may include a first press block 122 that is movable up and down by a movable member (not shown) along a first axial direction perpendicular to the pouch film 10b. The second press module 130 may include a second press block 132. The second press block 132 may be movable up and down by a movable member (not shown) along the first axial direction perpendicular to the pouch film 10b. The second press block 132 may have a shape corresponding to the battery cell receiving portion 10b1 and may be relatively larger in size than the first press block 122.

[0103] Therefore, in the manufacturing method of the pouch-type secondary battery of the present invention, the first press block and the second press block 132 stretch the pouch film 10b in two stages, and the second press block 132, which is relatively larger than the first press block 122, forms the battery cell accommodating portion 10b1, thereby effectively preventing excessive stretching of the corners of the battery cell accommodating portion 10b1.

[0104] 14, in a method for manufacturing a pouch-type secondary battery according to another embodiment of the present invention, the first press block 122 and the second press block 132 may have different shapes and sizes. For example, as shown in FIG. 14, the first press block 122 may have an ellipsoidal shape. That is, the curved surface of the first press block 122 having a spherical or ellipsoidal shape may effectively reduce variations in the pressure applied to the pressurized surface of the pouch film 10b.

[0105] The second press block 132 may have a shape corresponding to the battery cell accommodating portion 10b1. For example, if the internal space of the battery cell accommodating portion 10b1 has a flat hexahedron shape, the second press block 132 may have a hexahedron shape of a corresponding size.

[0106] Therefore, a method for manufacturing a pouch-type secondary battery according to another embodiment of the present invention includes a first press block 122 having a spherical or ellipsoidal shape and a first second press block 132 having a shape corresponding to the internal space of the battery cell accommodating portion 10b1. This allows the first press block 122 having a spherical or ellipsoidal shape to primarily pressurize the portion of the pouch film 10b where the battery cell accommodating portion 10b1 is to be formed without causing large variations in surface pressure. This allows uniform stretching to occur in the portion of the pouch film 10b where the battery cell accommodating portion 10b1 is to be formed, and effectively prevents excessive stretching from occurring at the corners of the battery cell accommodating portion 10b1.

[0107] Referring again to Figures 7 to 13, the grip module 110 used in the method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention may include a film die 112 having die openings 112a that open upward and downward, and a stripper 114 having stripper openings 114a that are provided to correspond to the die openings 112a.

[0108] Furthermore, step S01 in which the grip module 110 grips and fixes the edge portion 10b2 of the pouch film 10b may include a step of placing the pouch film 10b on the film die 112 so that the edge portion 10b2 of the pouch film 10b is positioned thereon.

[0109] Step S01 in which the grip module 110 grips and fixes the edge portion 10b2 of the pouch film 10b may be performed after the step of placing the pouch film 10b, by moving the stripper 114 up and down along the first axial direction and pressing the film die 112 with the edge portion 10b2 of the pouch film 10b interposed therebetween. For example, the stripper 114 may be provided so as to be movable up and down along the first axial direction by a moving member (not shown) such as a pneumatic cylinder. A portion of the stripper 114 may be connected to the pneumatic cylinder. The stripper 114 may be provided so as to press one surface (top surface) of the film die 112 with the pouch film 10b placed on the film die 112 by the moving member.

[0110] Therefore, the method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention includes a step of placing the pouch film 10b and a step of the stripper 114 pressing the film die 112, so that the edge portion 10b2 of the pouch film 10b can be stably fixed, and the stretching process of the pouch film 10b can be performed using the first press module 120 and the second press module 130 while precisely controlling the stretching rate.

[0111] Referring again to Figures 7 to 13, the first pressing step S02 of the method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention may include a step of pressing the pouch film 10b by inserting the first press block 122 into the die opening 112a in a first axial direction, and a step of the first press block 122 returning to its original position.

[0112] The second pressing step S03 may include a step of pressing the pouch film 10b by inserting the second press block 132 into the stripper opening 114a in the first axial direction, and a step of the second press block 132 returning to its original position again.

[0113] Therefore, the method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention includes a first pressing step S02 and a second pressing step S03, which perform pressing in opposite directions, thereby minimizing the curling phenomenon in which the edge 10b2 of the pouch film 10b is bent into a round shape. Furthermore, the first press module 120 and the second press module 13 stretch the pouch film 10b in two steps in opposite directions to form the battery cell receiving portion 10b1, thereby preventing excessive stretching of the corners of the battery cell receiving portion 10b1, which occurs when a pouch is formed by only one pressure molding in one direction.

[0114] 15 , a method for manufacturing a pouch-type secondary battery according to another embodiment of the present invention may further include a step of cooling at least one of the film die 112 and the stripper 114. Here, the pouch forming apparatus 100 may further include a cooling member 150. The cooling member 150 may be configured to cool at least one of the film die 112 and the stripper 114. For example, as shown in FIG. 15 , the pouch forming apparatus 100 according to another embodiment of the present invention may further include two cooling members 150 configured to cool the film die 112 and the stripper 114, respectively.

[0115] Therefore, the pouch forming apparatus 100 according to another embodiment of the present invention further includes a cooling member 150, which can cool at least one of the film die 112 and the stripper 114, thereby cooling the frictional heat generated during the stretching process, reducing the stretching rate at the edge 10b2 of the pouch film 10b fixed by the film die 112 and the stripper 114, and minimizing unnecessary deformation of the edge 10b2 of the pouch film 10b, such as curling.

[0116] The preferred embodiments of the present invention described above have been disclosed for illustrative purposes only, and those skilled in the art will appreciate that various modifications, changes, and additions may be made within the spirit and scope of the present invention. Such modifications, changes, and additions are to be considered as falling within the scope of the following claims. [Industrial Applicability]

[0117] This is described in the detailed description of the invention.

Claims

1. A pouch forming device for forming a pouch film for a pouch-type secondary battery, a grip module that grips and secures an edge of the pouch film; a first press module disposed on one side of the pouch film and pressurizing the pouch film toward the other side to stretch the pouch film; and a second press module disposed on the other side of the pouch film and configured to pressurize the pouch film in one direction to form a battery cell receiving portion that is stepped relative to the edge portion.

2. 2. The apparatus for forming a pouch for a secondary battery according to claim 1, further comprising: a control unit that controls operations of the first press module and the second press module such that the press forming by the second press module is performed after the press forming by the first press module, in order to prevent a curling phenomenon in which the edge of the pouch film is bent round and to reduce an elongation rate of a corner of the battery cell accommodating portion.

3. The grip module includes: a film die having a vertically open die opening that pressurizes and supports the lower surface of the pouch film when the pouch film is pressurized; and The pouch forming apparatus for a secondary battery according to claim 1 , further comprising a stripper having a stripper opening corresponding to the die opening, the stripper pressing and supporting an upper surface of the pouch film when the pouch film is pressurized and formed.

4. The apparatus for forming a pouch for a secondary battery according to claim 3 , wherein the die opening and the stripper opening are formed to correspond to the shape of the battery cell receiving portion.

5. 4. The pouch forming apparatus for a secondary battery according to claim 3, wherein the first press module includes a first press block that is inserted sequentially into the die opening and the stripper opening along a first axial direction perpendicular to the pouch film, and the second press module includes a second press block that is inserted sequentially into the stripper opening and the die opening along the first axial direction perpendicular to the pouch film.

6. The secondary battery pouch molding device according to claim 5 , wherein the second press block has a shape corresponding to the battery cell accommodating portion.

7. The apparatus for forming a pouch for a secondary battery according to claim 5 , wherein the first press block has a size relatively smaller than that of the second press block.

8. the first press block has an ellipsoid shape; The secondary battery pouch molding device according to claim 7 , wherein the second press block has a shape corresponding to the battery cell accommodating portion.

9. 6. The apparatus for forming a pouch for a secondary battery according to claim 5, wherein the first press module includes a first press platform having a first stationary groove formed therein in which the first press block is housed, and the first press block is configured to move up and down relative to the first press platform.

10. 10. The apparatus for forming a pouch for a secondary battery according to claim 9, wherein the second press module includes a second press platform having a second stationary groove formed therein in which the second press block is housed, and the second press block is configured to move up and down relative to the second press platform.

11. 11. The pouch forming apparatus for secondary batteries according to claim 9 or 10, wherein when the second press block presses and forms the pouch film, the first press block and the first press platform support one surface of the second press block to generate a repulsive force against the pressing force of the second press block.

12. A method for manufacturing a pouch-type secondary battery using a pouch forming device including a grip module, a first press module, and a second press module, a gripping step in which the gripping module holds and secures an edge of the pouch film; the first press module disposed on one side of the pouch film presses the pouch film primarily toward the other side to stretch the pouch film; and secondly pressing the pouch film in one direction by the second press module disposed on the other side of the pouch film to form a battery cell receiving portion having a step with respect to the edge portion.

13. 13. The method of manufacturing a pouch-type secondary battery according to claim 12, wherein the second pressing is performed after the first pressing to prevent a curling phenomenon in which the edge of the pouch film is bent into a round shape and to reduce an elongation rate of a corner of the battery cell receiving portion.

14. The grip module includes a film die having a die opening formed therein and a stripper having a stripper opening formed therein corresponding to the die opening; The method of manufacturing a pouch-type secondary battery according to claim 12 , wherein the gripping step comprises raising the film die and pressing and fixing the pouch film between the film die and the stripper.

15. The method for manufacturing a pouch-type secondary battery according to claim 14 , wherein the film die is configured to rise together with the first press module.

16. the first press module includes a first press platform and a first press block; The method of manufacturing a pouch-type secondary battery according to claim 15, wherein, in the first pressing, the first press block moves up and down relative to the first press platform.

17. The method of claim 16, wherein in the first pressing, the first press block is inserted into the die opening and the stripper opening sequentially.

18. The method of manufacturing a pouch-type secondary battery according to claim 17, wherein the second pressing is performed after the first press block is returned to its original position.

19. the second press module includes a second press platform and a second press block; The method of claim 18, wherein in the second pressing, the second press block is inserted into the stripper opening and the die opening sequentially.

20. 20. The method of manufacturing a pouch-type secondary battery according to claim 19, wherein the second press block has a shape corresponding to the battery cell receiving portion and is relatively larger in size than the first press block.

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