Equipment and methods for forming pouches, and pouches for secondary batteries.

Abstract

The invention relates to a pouch-forming apparatus comprising a pouch-forming device for forming a containment for an electrode assembly within a pouch membrane; and a steam-spraying device for spraying steam toward the pouch membrane to increase the moisture content of the plastic layer enclosed in the pouch membrane, thereby increasing its elongation. As a result, it is possible to prevent cracking during pouch membrane formation.

Description

Pouch forming device and forming method, and pouch for secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0141479, filed October 20, 2023, and Korean Patent Application No. 10-2024-0142458, filed October 17, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a forming device and forming method for forming a receptacle having a sunken shape in a pouch film, and a pouch for a secondary battery formed thereby.

[0005] In general, a secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be recharged. These secondary batteries are widely used in advanced electronic devices such as phones, laptop computers, and camcorders.

[0006] The above secondary battery is classified into a can-type secondary battery in which the electrode assembly is built into a metal can, and a pouch-type secondary battery in which the electrode assembly is built into a pouch.

[0007] The above pouch-type secondary battery includes an electrode assembly and a pouch that accommodates the electrode assembly, and the electrode assembly has a structure in which positive and negative electrodes are alternately arranged with a separator interposed therebetween. The pouch includes an electrode assembly receiving portion that accommodates the electrode assembly, and a sealing portion that seals the electrode assembly receiving portion.

[0008] Here, the method for manufacturing the pouch includes a process of preparing a pair of pouch films, a process of forming an electrode assembly receiving portion corresponding to the pair of pouch films, and a process of sealing the edges while arranging the pair of pouch films correspondingly.

[0009] However, the conventional pouch manufacturing method had a problem in that cracks occurred at the corners of the electrode assembly receiving portion during forming of the pouch film.

[0010] [Prior art document] Patent Publication No. 2023-0016581.

[0011] The problem to be solved by the present invention is to provide a pouch forming device and forming method capable of increasing the elongation of a pouch film by increasing the moisture content of the pouch film, thereby preventing the occurrence of cracks during forming of the pouch film.

[0012] Another problem to be solved by the present invention is to provide a pouch for a secondary battery manufactured by the pouch forming device or forming method.

[0013] A pouch forming device according to an embodiment of the present invention may include a pouch forming unit that forms a receiving portion having a sunken shape into a pouch film; and a steam spraying unit that sprays steam toward the pouch film to increase the moisture content of a resin layer included in the pouch film.

[0014] The above pouch forming unit may include a die having a forming groove on the upper surface where the pouch film is placed; and a punch provided on the upper portion of the die and inserted into the forming groove to form the receiving portion on the pouch film. The water vapor injection unit may include a main injection unit that sprays water vapor toward the pouch film placed on the upper portion of the die.

[0015] The above steam injection unit can inject steam at a temperature lower than room temperature.

[0016] The above steam injection unit may be provided as an ultrasonic sprayer that splits water particles using ultrasonic waves to generate and spray steam.

[0017] The above pouch film may include an insulating layer, a resin layer, a metal layer, and a protective layer arranged sequentially. The main injection unit may include a first main injection unit that injects water vapor toward the insulating layer located at the outermost edge of the pouch film; and a second main injection unit that injects water vapor toward a side of the pouch film.

[0018] The above steam injection unit can spray steam for 30 seconds to 2 minutes.

[0019] In the above forming home, a discharge hole may be formed to discharge water droplets in which water vapor is condensed to the outside.

[0020] The above discharge hole can be formed at a corner of the forming home.

[0021] The above pouch forming device may further include a drying unit that dries the pouch film so that moisture contained in the resin layer is removed after the receiving portion is formed on the pouch film.

[0022] The above pouch forming device may further include a transport unit for transporting the pouch film so that it is arranged on the upper surface of the die. The steam injection unit may further include an auxiliary spray unit for spraying steam toward the pouch film transported by the transport unit.

[0023] A pouch forming method according to an embodiment of the present invention may include a spraying step of spraying water vapor toward a pouch film to increase the moisture content of a resin layer included in the pouch film; and a forming step of forming a receiving portion having a sunken shape in the pouch film.

[0024] In the above injection step, water vapor at a temperature lower than room temperature can be injected.

[0025] The above pouch film may include an insulating layer, a resin layer, a metal layer, and a protective layer arranged sequentially. In the spraying step, water vapor may be sprayed toward the insulating layer located at the outermost part of the pouch film and toward the side of the pouch film, respectively.

[0026] The above pouch forming method may further include, prior to the spraying step, a placement step in which the pouch film is placed on the upper surface of a die having a forming groove. The spraying step may include a main spraying process in which water vapor is sprayed toward the pouch film placed on the upper surface of the die.

[0027] The above pouch forming method may further include, prior to the placement step, a transfer step of transferring the pouch film toward the die. The spraying step may further include an auxiliary spraying process of spraying water vapor toward the pouch film during the transfer step.

[0028] The above forming step may include a discharge process for discharging water droplets remaining in the forming groove due to condensation of water vapor.

[0029] The above pouch forming method may further include, after the forming step, a drying step of drying the pouch film so that moisture contained in the resin layer is removed.

[0030] A pouch for a secondary battery according to an embodiment of the present invention may have a receiving portion having a sunken shape formed therein. The pouch for a secondary battery may include an insulating layer positioned at the outermost portion; a protective layer positioned at the innermost portion; a metal layer positioned between the insulating layer and the protective layer; and a resin layer positioned between the insulating layer and the metal layer. The moisture content of the resin layer may be 700 to 2000 ppm.

[0031] The moisture content of the above resin layer may be 1000 to 1500 ppm.

[0032] The above insulating layer may have a thickness of 8 μm to 15 μm.

[0033] According to a preferred embodiment of the present invention, the steam injection unit of the pouch forming device can increase the moisture content of the resin layer contained in the pouch film by injecting steam toward the pouch film. This can increase the elongation of the pouch film, thereby preventing the occurrence of cracks during pouch film forming.

[0034] In addition, the steam injection unit may include a main injection unit that injects steam toward the pouch film disposed on the upper portion of the die. As a result, the moisture content of the pouch film can be stably increased.

[0035] In addition, the main injection unit may include a first main injection unit that injects water vapor toward the outermost insulating layer, and a second main injection unit that injects water vapor toward the side of the pouch film. As a result, the moisture content of the resin layer can be stably increased.

[0036] In addition, the above steam injection unit can inject steam at a temperature lower than room temperature. This can prevent deformation of the pouch film due to steam.

[0037] Additionally, a discharge hole may be formed in the forming groove of the die of the pouch forming device to discharge water droplets formed by condensation of water vapor to the outside. This allows stable forming of the receiving portion on the pouch film.

[0038] Additionally, the drying unit of the pouch forming device can remove moisture contained in the resin layer by drying the pouch film formed by the receiving unit. This can prevent defects from occurring in the subsequent pouch sealing process.

[0039] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0040] FIG. 1 is a perspective view illustrating a secondary battery including a pouch according to an embodiment of the present invention.

[0041] Figure 2 is a cross-sectional view illustrating a pouch according to an embodiment of the present invention.

[0042] Figure 3 is an enlarged view of part A shown in Figure 2.

[0043] Figure 4 is a process diagram schematically illustrating a pouch forming device according to an embodiment of the present invention.

[0044] Figure 5 is a perspective view showing the main injection unit of a pouch forming device according to an embodiment of the present invention.

[0045] Fig. 6 is a cross-sectional view showing a discharge hole in a pouch forming device according to an embodiment of the present invention.

[0046] Figure 7 is a process diagram illustrating an auxiliary injection unit of a pouch forming device according to an embodiment of the present invention.

[0047] Figure 8 is a flowchart showing a pouch forming method according to an embodiment of the present invention.

[0048] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and similar parts have been designated with similar reference numerals throughout the specification.

[0049] FIG. 1 is a perspective view showing a secondary battery including a pouch according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a pouch according to an embodiment of the present invention, and FIG. 3 is an enlarged view of part A shown in FIG. 2.

[0050] The secondary battery (1) may include an electrode assembly (11) as illustrated in FIGS. 1 to 3, and a pouch (12) that accommodates the electrode assembly (11).

[0051] The above electrode assembly (11) may have a structure in which a plurality of electrodes and a plurality of separators are alternately arranged. The plurality of electrodes may include a positive electrode and a negative electrode.

[0052] The pouch (12) according to an embodiment of the present invention is a pouch for a secondary battery. The pouch (12) is intended to accommodate an electrode assembly (11) and may include a pair of pouch films (13). The pair of pouch films (13) may include a receiving portion (131) for accommodating the electrode assembly (11) and a sealing portion (132) formed on the edge of the receiving portion (131).

[0053] That is, the receiving portion (131) formed on one pouch film (13) and the receiving portion (131) formed on the other pouch film (13) can form a receiving space for receiving the electrode assembly (11) together. The sealing portion (132) formed on one pouch film (13) and the sealing portion (132) formed on the other pouch film (13) can seal the receiving space by being heat-sealed to each other.

[0054] However, this is not limited to this, and it is also possible for only one pouch film (13) among a pair of pouch films (13) to be provided with a receiving portion (131). In this case, the other pouch film (13) may be formed flat. Such an example is well known as a 1-cup structure, and thus, those skilled in the art will readily understand it.

[0055] The above pouch film (13) may include an insulating layer (1311), a resin layer (1312), a metal layer (1313), and a protective layer (1314) sequentially arranged as illustrated in FIG. 3. That is, the insulating layer (1311) may be arranged on the outermost side of the pouch film (13), and the protective layer (1314) may be arranged on the innermost side. In addition, the metal layer (1313) may be positioned between the insulating layer (1311) and the protective layer (1314). In addition, the resin layer (1312) may be positioned between the insulating layer (1311) and the metal layer (1313).

[0056] The insulating layer (1311) may have a moisture-permeable material. For example, the insulating layer (1311) may include a polyethylene terephthalate material.

[0057] The resin layer (1312) may have a material that can easily contain moisture. For example, the resin layer (1312) may include a nylon material.

[0058] The metal layer (1313) may include an aluminum material. The protective layer (1314) may include a polypropylene material.

[0059] However, it is not limited thereto, and a person skilled in the art will be able to appropriately select the material of each layer of the pouch film (13) within a well-known range.

[0060] Meanwhile, the pouch (12) can be manufactured by forming a receiving portion (131) that receives the electrode assembly (11) into a pair of pouch films (13). At this time, the pouch forming device (2) according to the embodiment of the present invention can be used.

[0061] In particular, the pouch forming device (2) can increase the elongation of the pouch film (13), thereby preventing cracks from occurring when forming the receiving portion (131) in the pouch film (13).

[0062] Hereinafter, a pouch forming device according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0063] FIG. 4 is a process diagram schematically illustrating a pouch forming device according to an embodiment of the present invention, and FIG. 5 is a perspective view illustrating a main injection unit of a pouch forming device according to an embodiment of the present invention.

[0064] A pouch forming device (2) according to an embodiment of the present invention may include a pouch forming unit (21) that forms a receiving portion (131) having a sunken shape in a pouch film (13), as shown in FIGS. 4 and 5, and a steam spraying unit (22) that sprays steam toward the pouch film (13) to increase the moisture content of a resin layer (1312) included in the pouch film (13).

[0065] The pouch forming part (21) is for forming a receiving part (131) having a sunken shape into the pouch film (13).

[0066] That is, the pouch forming part (21) may include a die (211) having a forming groove (2111) provided on the upper surface where the pouch film (13) is placed, and a punch (212) provided on the upper portion of the die (211) and inserted into the forming groove (2111) to form a receiving part (131) on the pouch film (13).

[0067] At least a portion of the punch (212) can be inserted into the forming groove (2111) while pressing the pouch film (13), thereby forming the receiving portion (131) in the pouch film (13).

[0068] The steam injection unit (22) is intended to increase the elongation of the pouch film (13) by using steam. The steam injection unit (22) may be configured to spray steam. Here, steam includes not only water in a gaseous state but also water in a liquid state that is sprayed.

[0069] That is, the steam injection unit (22) sprays steam toward the pouch film (13) to increase the moisture content of the resin layer (1312) included in the pouch film (13), thereby increasing the elongation of the pouch film (13).

[0070] The steam injection unit (22) may include a main injection unit (221) that injects steam toward the pouch film (13) placed on the upper surface of the die (211) before forming the pouch film (13).

[0071] In more detail, the main injection unit (221) may include a first main injection unit (2211) that injects steam toward the insulating layer (1311), and a second main injection unit (2212) that injects steam toward the side of the pouch film (13).

[0072] When the first main injector (2211) injects water vapor toward the insulating layer (1311) of the pouch film (13), some of the water vapor penetrates the insulating layer (1311) and is impregnated into the resin layer (1312), thereby increasing the moisture content of the resin layer (1312).

[0073] When the second main injector (2212) injects water vapor toward the side of the pouch film (13), some of the water vapor is absorbed by the resin layer (1312) exposed to the side of the pouch film (13), and thus the moisture content of the resin layer (1312) may increase.

[0074] In particular, the main injection unit (221) can inject water vapor for a preset time so that the entire resin layer (1312) included in the pouch film (13) has a preset moisture impregnation capacity. The preset time may be 30 seconds to 10 minutes. For example, the preset time may be approximately 2 minutes. If the preset time is less than 30 seconds, the pouch film (13) cannot be sufficiently impregnated with moisture, and if it is more than 10 minutes, there is a problem that the forming process time is excessively increased.

[0075] The resin layer (1312) of the pouch film (13) may include a nylon material. Nylon has excellent properties such as tensile strength, wear resistance, elasticity, and moisture absorption, and is therefore suitable as a material for the resin layer (1312).

[0076] The insulating layer (1311) of the pouch film (13) may have a thickness of 8 ㎛ to 15 ㎛ in order to increase water vapor permeability. For example, the thickness of the insulating layer (1311) may be approximately 12 ㎛. If the thickness of the insulating layer (1311) is 8 ㎛ or less, the insulating layer (1311) may be easily damaged due to external contact, and if it is 15 ㎛ or more, there is a problem that it is difficult to increase the moisture content of the resin layer (1312) because the water vapor permeability is low.

[0077] The resin layer (1312) of the pouch film (13) may have a thickness of 20 μm to 30 μm. For example, the thickness of the resin layer (1312) may be approximately 25 μm.

[0078] The metal layer (1313) of the pouch film (13) may have a thickness of 45 μm to 75 μm. For example, the thickness of the metal layer (1313) may be approximately 60 μm.

[0079] The protective layer (1314) of the pouch film (13) may have a thickness of 60 μm to 100 μm. For example, the thickness of the protective layer (1314) may be approximately 80 μm.

[0080] Those skilled in the art will understand that the thickness range of each layer of the pouch film (13) can also be applied to the pouch (12) according to the embodiment of the present invention.

[0081] Meanwhile, the steam injection unit (22) can inject steam having a temperature of 100 degrees Celsius or lower. Preferably, the steam injection unit (22) can inject steam having a temperature lower than room temperature. Accordingly, the pouch film (13) can be prevented from being damaged or deformed by the steam.

[0082] For example, the steam injection unit (22) may be provided as an ultrasonic sprayer that splits water particles using ultrasonic waves to generate and spray steam.

[0083] The steam injection unit (22) can increase the elongation of the pouch film (13) by increasing the moisture content of the resin layer (1312) included in the pouch film (13). As the elongation of the resin layer (1312) increases, the elongation of the pouch film (13) increases, thereby preventing cracks from occurring during forming of the pouch film (13). In other words, external exposure of the metal layer (1313) due to cracks can be prevented.

[0084] In more detail, the moisture content of the resin layer (1312) of the pouch film (13) may be 700 to 2000 ppm. Preferably, the moisture content of the resin layer (1312) may be 1000 to 1500 ppm.

[0085] If the moisture content of the resin layer (1312) is less than 700 ppm, the elongation increase effect of the pouch film (13) may be minimal. In addition, considering the elongation increase effect of the pouch film (13), there is a problem that the amount of water vapor sprayed onto the pouch film (13) or the spraying time is unnecessarily consumed when the moisture content of the resin layer (1312) is greater than 2000 ppm.

[0086] Those skilled in the art will understand that the moisture content of the resin layer (1312) of such a pouch film (13) can also be applied to the pouch (12) according to an embodiment of the present invention.

[0087] Meanwhile, if previously sprayed water vapor condenses and water droplets remain within the forming groove (2111) of the die (211), a problem may arise in which the receiving portion (131) is not formed accurately in the pouch film (13). To solve this problem, a discharge hole (2112) may be formed in the forming groove (2111) to discharge water droplets formed as the water vapor condenses to the outside.

[0088] Fig. 6 is a cross-sectional view showing a discharge hole in a pouch forming device according to an embodiment of the present invention.

[0089] A discharge hole (2112) for discharging water droplets of condensed water vapor to the outside may be formed in the forming groove (2111) of the die (211).

[0090] The discharge hole (2112) may be formed at a corner of the forming groove (2111). The discharge hole (2112) may be formed to slope downward from the bottom surface of the forming groove (2111) toward the bottom surface of the die (211). Accordingly, water droplets remaining in the forming groove (2111) may be effectively removed.

[0091] Meanwhile, the pouch forming device (2) may further include a drying unit (23) for drying the pouch film (13) formed in the receiving unit (131).

[0092] The drying unit (23) can evaporate and remove moisture contained in the resin layer (1312) by increasing the temperature of the pouch film (13) in which the receiving unit (131) is formed. Accordingly, when manufacturing a pouch (12) by heat-sealing the pouch films (13) together in a subsequent process, it is possible to prevent the sealing force of the pouch film (13) from weakening due to moisture.

[0093] Figure 7 is a process diagram illustrating an auxiliary injection unit of a pouch forming device according to an embodiment of the present invention.

[0094] Meanwhile, the pouch forming device (2) may further include a transport unit (213) that transports the pouch film (13) so that it is arranged on the upper surface of the die (211). For example, the transport unit (213) may include a conveyor belt. However, the configuration of the transport unit (213) is not limited thereto.

[0095] The steam injection unit (22) may further include an auxiliary injection unit (222) that injects steam toward the pouch film (13) being transported by the transport unit (213). The auxiliary injection unit (222) may increase the moisture content of the resin layer (1312) included in the pouch film (13) to increase the elongation.

[0096] In more detail, the auxiliary injection unit (222) may include a first auxiliary injection unit (2221) that injects water vapor toward the insulating layer (1311) of the pouch film (13) being transported by the transport unit (213) and a second auxiliary injection unit (2222) that injects water vapor toward the side of the pouch film (13).

[0097] When the first auxiliary injector (2221) injects water vapor toward the insulating layer (1311), some of the water vapor may penetrate the insulating layer (1311) and be impregnated into the resin layer (1312), thereby increasing the moisture content of the resin layer (1312).

[0098] When the second auxiliary injector (2222) injects water vapor toward the side of the pouch film (13), some of the water vapor may be impregnated into the resin layer (1312) exposed to the side of the pouch film (13), and thus the moisture content of the resin layer (1312) may increase.

[0099] Accordingly, the steam injection unit (22) can increase the moisture content of the resin layer (1312) included in the pouch film (13) by injecting steam toward the pouch film (13), thereby increasing the elongation of the pouch, and as a result, preventing cracks from occurring during forming of the pouch film (13).

[0100] Figure 8 is a flowchart showing a pouch forming method according to an embodiment of the present invention.

[0101] A pouch forming method according to an embodiment of the present invention may include a spraying step (S30) of spraying water vapor toward a pouch film (13) to increase the moisture content of a resin layer (1312) included in the pouch film (13), and a forming step (S40) of forming a receiving portion (131) having a sunken shape in the pouch film (13).

[0102] The above pouch forming method may further include a placement step (S20) in which a pouch film (13) is placed on the upper surface of a die (211) having a forming groove (2111) before the injection step (S30).

[0103] The above pouch forming method may further include a transfer step (S10) of transferring the pouch film (13) toward the die (211) before the placement step (S20).

[0104] The above pouch forming method may further include, after the forming step (S40), a drying step (S50) of drying the pouch film (13) so that moisture contained in the resin layer (1312) is removed.

[0105] In relation to this pouch forming method, the pouch film (13) may include an insulating layer (1311), a resin layer (1312), a metal layer (1313), and a protective layer (1314) sequentially arranged as described above.

[0106] Below, each step is explained in more detail.

[0107] In the transport step (S10), the pouch film (13) can be transported to the die (211) using the transport unit (213).

[0108] In the placement step (S20), the pouch film (13) transferred in the transfer step (S10) can be placed on the upper surface of the die (211). For example, the pouch film (13) can be absorbed using a moving means (not shown) such as an absorption device and then placed on the upper surface of the die (211). As described above, a forming groove (2111) can be formed on the upper surface of the die (211).

[0109] The spraying step (S30) may be a step for spraying steam onto the pouch film (13) to increase the elongation of the pouch film (13) and thereby increase the moisture content of the resin layer (1312). The spraying step (S30) may be performed by a steam spraying unit (22).

[0110] The injection step (S30) may include a main injection process of injecting water vapor toward a pouch film (13) placed on the upper surface of the die (211). The main injection process may be performed by a main injection unit (221).

[0111] The injection step (S30) may further include an auxiliary injection process of injecting steam toward the pouch film (13) during the transport of the pouch film (13) in the transport step (S10). The auxiliary injection process may be performed by an auxiliary injection unit (222).

[0112] In the spraying step (S30), water vapor can be sprayed toward the insulating layer (1311) located at the outermost part of the pouch film (13) and the side of the pouch film (13). When water vapor is sprayed toward the insulating layer (1311), some of the water vapor penetrates the insulating layer (1311) and is impregnated into the resin layer (1312), thereby increasing the moisture content of the resin layer (1312). In addition, when water vapor is sprayed toward the side of the pouch film (13), some of the water vapor is impregnated into the resin layer (1312) exposed to the side of the pouch film (13), thereby increasing the moisture content of the resin layer (1312).

[0113] In more detail, during the main injection process, the first main injector (2211) can inject water vapor toward the insulating layer (1311) of the pouch film (13) placed on the upper surface of the die (211), and the second main injector (2212) can inject water vapor toward the side of the pouch film (13).

[0114] In more detail, in the auxiliary injection process, in the transport step (S10), the first auxiliary injection device (2221) can spray water vapor toward the insulating layer (1311) of the pouch film (13) being transported, and the second auxiliary injection device (2222) can spray water vapor toward the side of the pouch film (13).

[0115] Meanwhile, in the above-described spraying step (S30), steam having a temperature lower than 100 degrees Celsius can be sprayed, and preferably steam having a temperature lower than room temperature can be sprayed. This is to prevent deformation of the pouch film (13) due to the steam.

[0116] In the forming step (S40), the punch (212) can form a receiving portion (131) in the pouch film (13) placed on the die (211). More specifically, in the forming step (S40), the punch (212) can be lowered to pressurize the pouch film (13) and be inserted into the forming groove (2111) of the die (211). Accordingly, a portion of the pouch film (13) can be inserted into the forming groove (2111) together with the punch (212), and the receiving portion (131) can be formed in the pouch film (13).

[0117] The forming step (S40) may include a discharge process for discharging water droplets remaining in the forming groove (2111) before forming the pouch film (13). In the discharge process, water droplets remaining in the forming groove (2111) due to condensation of water vapor may be discharged to the outside through a discharge hole (2112) formed at a corner of the forming groove (2111).

[0118] The drying step (S50) can remove moisture contained in the resin layer (1312) by drying the pouch film (13) formed in the receiving portion (131) after the forming step (S40).

[0119] For example, in the drying step (S50), the temperature of the pouch film (13) in which the receiving portion (131) is formed can be increased using a heating means such as a heater. Then, the moisture contained in the resin layer (1312) of the pouch film (13) can be evaporated and removed. Accordingly, when manufacturing a pouch (12) by heat-sealing the pouch films (13) together in a subsequent process, the sealing force of the pouch film (13) can be prevented from being weakened due to moisture.

[0120] Therefore, the pouch forming method according to the embodiment of the present invention can significantly reduce the defect rate of the pouch (12) and manufacture a high-quality pouch film (13).

[0121] Below, an experiment to confirm the elongation and formability according to the moisture content of the pouch film (13) is described.

[0122] Here, the pouch film (hereinafter referred to as the test material) includes an insulating layer (1311), a resin layer (1312), a metal layer (1313), and a protective layer (1314) sequentially arranged as described above.

[0123] The insulating layer (1311) of the above test piece is made of polyethylene terephthalate, the resin layer (1312) is made of nylon, the metal layer (1313) is made of aluminum, and the protective layer (1314) is made of polypropylene. In addition, the thickness of the insulating layer (1311) is 12 μm, the thickness of the resin layer (1312) is 25 μm, the thickness of the metal layer (1313) is 60 μm, and the thickness of the protective layer (1314) is 80 μm.

[0124] The first experimental condition is to place five test specimens in a dry room without moisture for one day and then measure the moisture content (ppm).

[0125] The second experimental condition is to place five experimental items in an experimental room at room temperature (20-30℃) for one day and then measure the moisture content (ppm).

[0126] The third experimental condition is to place five test items in an experimental room with 60 degrees Celsius and 90% humidity for 10 minutes, and then measure the moisture content (ppm).

[0127] The fourth experimental condition is to place five test items in an experimental room with a temperature of 60 degrees Celsius and 90% humidity for one day, and then measure the moisture content (ppm).

[0128] Here, the moisture content of the test specimens subjected to experimental conditions 1 through 4 is measured using a commonly used moisture content measuring device. For example, the MOICO-A19 from Igongyo can be used. Furthermore, the elongation is measured by pulling both ends of the test specimens subjected to experimental conditions 1 through 4.

[0129] Prepare five identical experimental specimens and mark them from 1 to 5.

[0130] As a result of measuring the moisture content and elongation of the test specimens that passed the above first to fourth experimental conditions, the results shown in Table 1 below were obtained.

[0131] Experimental material Pouch film Experimental condition 1 Experimental condition 2 Experimental condition 3 Experimental condition 4 Experimental condition Moisture content (ppm) 1 1 4 5 1 1 6 6 1 7 5 0 7 6 6 2 2 8 5 8 2 7 1 5 7 6 7 4 2 9 3 2 3 1 1 0 1 1 5 4 7 7 3 9 5 4 2 2 5 7 8 3 1 5 9 2 7 3 6 1 5 1 6 0 1 2 9 0 1 5 0 6 7 3 1 7 Average 2 0 9 1 0 1 5 1 5 9 4 7 4 3 4 Elongation rate (%) 1 6 3 6 4 8 0 8 2 2 6 9 7 2 7 3 7 3 3 5 8 6 2 8 3 7 3 4 7 3 6 1 7 9 8 3 5 6 8 6 5 6 4 8 3 Average 6 6 6 5 7 6 7 9

[0132] Referring to Table 1 above, it can be confirmed that the moisture content of the test material significantly increases in the experimental room with the third and fourth experimental conditions of 60 degrees Celsius and 90% humidity. This confirms that the moisture content of the pouch film increases when water vapor is sprayed onto the pouch film in the present invention.

[0133] Additionally, it was confirmed that the elongation of the test specimens subjected to the third and fourth experimental conditions increased. This confirms that, in the present invention, when the moisture content is increased by spraying water vapor onto the pouch film, the elongation also improves. In other words, since the elongation of the pouch film increases, cracks can be prevented from occurring during molding.

[0134] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and various embodiments are possible derived from the meaning and scope of the claims and their equivalent concepts.

[0135] [Explanation of symbols]

[0136] 1: Secondary battery 11: Electrode assembly

[0137] 12: Pouch 13: Pouch film

[0138] 131: Receptacle 1311: Insulating layer

[0139] 1312: Resin layer 1313: Metal layer

[0140] 1314: Protective layer 132: Sealing part

[0141] 2: Pouch forming device 21: Pouch forming section

[0142] 211: Die 2111: Forming Home

[0143] 2112: Discharge hole 212: Punch

[0144] 213: Transfer unit 22: Steam injection unit

[0145] 221: Main injection unit 2211: First main injection unit

[0146] 2212: Second main injector 222: Auxiliary injector unit

[0147] 2221: First auxiliary injector 2222: Second auxiliary injector

[0148] 23: Drying section

Claims

1. A pouch forming part that forms a receptacle having a sunken shape into a pouch film; and A pouch forming device including a steam injection unit that sprays steam toward the pouch film to increase the moisture content of a resin layer included in the pouch film.

2. In claim 1, The above pouch forming part is, A die having a forming groove provided on the upper surface on which the pouch film is placed; and A punch is provided on the upper part of the die and is inserted into the forming groove to form the receiving portion on the pouch film. The above steam injection unit, A pouch forming device including a main injection unit that injects water vapor toward the pouch film disposed on the upper portion of the die.

3. In claim 1, The above steam injection unit is a pouch forming device that injects steam at a temperature lower than room temperature.

4. In claim 1, The above steam injection unit is a pouch forming device provided with an ultrasonic sprayer that splits water particles using ultrasonic waves to generate and spray steam.

5. In claim 2, The above pouch film includes an insulating layer, a resin layer, a metal layer, and a protective layer arranged sequentially, The above main injection unit is, A first main injector that injects water vapor toward the insulating layer located at the outermost surface of the pouch film; and A pouch forming device comprising a second main injector for injecting water vapor toward the side of the pouch film.

6. In claim 1, The above steam injection unit is a pouch forming device that injects steam for 30 seconds to 2 minutes.

7. In claim 2, A pouch forming device in which a discharge hole is formed in the above forming home to discharge water droplets in which water vapor is condensed to the outside.

8. In claim 7, The above discharge hole is a pouch forming device formed at a corner of the above forming home.

9. In claim 1, A pouch forming device further comprising a drying unit for drying the pouch film so that moisture contained in the resin layer is removed after the receiving portion is formed on the pouch film.

10. In claim 2, Further comprising a transport unit for transporting the pouch film so that it is placed on the upper surface of the die, The above steam injection unit, A pouch forming device further comprising an auxiliary spraying unit that sprays water vapor toward the pouch film transported by the transporting unit.

11. A spraying step of spraying water vapor toward the pouch film to increase the moisture content of the resin layer included in the pouch film; and A pouch forming method comprising a forming step of forming a receiving portion having a sunken shape into the above pouch film.

12. In claim 11, A pouch forming method for spraying steam at a temperature lower than room temperature during the above spraying step.

13. In claim 11, The above pouch film includes an insulating layer, a resin layer, a metal layer, and a protective layer arranged sequentially, A pouch forming method in which, during the above-mentioned spraying step, water vapor is sprayed toward the insulating layer located at the outermost part of the pouch film and toward the side of the pouch film.

14. In claim 11, Before the above injection step, a placement step is further included in which the pouch film is placed on the upper surface of a die having a forming groove, The above injection step is, A pouch forming method including a main injection process for injecting water vapor toward the pouch film disposed on the upper surface of the die.

15. In claim 14, Before the above placement step, further comprising a transfer step of transferring the pouch film toward the die, The above injection step is, A pouch forming method further comprising an auxiliary spraying process of spraying water vapor toward the pouch film during the transport of the pouch film in the above transporting step.

16. In claim 14, The above forming step is, A pouch forming method including a discharge process for discharging water droplets remaining in the forming groove due to condensation of water vapor.

17. In claim 11, A pouch forming method further comprising, after the forming step, a drying step of drying the pouch film so that moisture contained in the resin layer is removed.

18. In a pouch for a secondary battery in which a receiving portion having a sunken shape is formed, The insulating layer located at the outermost layer; A protective layer located at the innermost part; A metal layer positioned between the insulating layer and the protective layer; and Including a resin layer positioned between the insulating layer and the metal layer, A pouch for a secondary battery, wherein the moisture content of the resin layer is 700 to 2000 ppm.

19. In paragraph 18, A pouch for a secondary battery, wherein the moisture content of the resin layer is 1000 to 1500 ppm.

20. In paragraph 18, A pouch for a secondary battery, wherein the insulating layer has a thickness of 8 ㎛ to 15 ㎛.

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