Secondary battery pouch manufacturing apparatus and manufacturing method

Abstract

The present invention relates to a secondary battery pouch manufacturing method and, more specifically, to a secondary battery pouch manufacturing method and manufacturing apparatus, which are capable of organically and efficiently performing plasma surface treatment. According to one embodiment of the present invention, the secondary battery pouch manufacturing method can be provided, the method comprising: a transfer step of periodically transferring a pouch sheet from a pouch roll by means of an unwinder and stopping and supplying same; a forming step of forming the pouch sheet, which is stopped after being transferred in the transfer step, so as to form a cup in which an electrode assembly is accommodated; and a surface treatment step of performing plasma surface treatment on the pouch sheet, which is stopped after being transferred in the transfer step.

Description

Secondary battery pouch manufacturing device and manufacturing method

[0001] The present invention relates to a method for manufacturing a pouch for a secondary battery, and more specifically, to a method for manufacturing a pouch for a secondary battery and a manufacturing apparatus capable of organically and efficiently performing plasma surface treatment.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2024-0039514, filed March 22, 2024, the entire contents of which are incorporated herein by reference.

[0003] A secondary battery is a battery that can be used repeatedly through a discharge process that converts chemical energy into electrical energy and a charging process that converts electrical energy into chemical energy.

[0004] Secondary batteries may include nickel-cadmium (Ni-Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium-metal batteries, lithium-ion (Li-Ion) batteries, and lithium-ion polymer batteries (Li-Ion Polymer Batteries, hereinafter referred to as “LIPB”).

[0005] Lithium secondary batteries have a cycle life of about 500 times or more and a short charging time of about 1 to 2 hours. They are about 30 to 40% lighter than nickel-hydrogen batteries, allowing for weight reduction. Among existing secondary batteries, they have the highest voltage per unit cell (30 to 37 V) and excellent energy density, making them ideal for mobile devices.

[0006] Lithium secondary batteries can be manufactured as pouch-type secondary batteries in which the battery cells are sealed in a pouch made of aluminum packaging material.

[0007] A pouch-type secondary battery may include a battery cell accommodated in a pouch, which is a sealing material, a lead tab electrically connected to electrode tabs of electrodes provided in the battery cell and extending outward from the pouch, and an insulating film that electrically insulates the lead tab. In particular, the pouch may seal the battery cell accommodated therein by heat-sealing the inner surface of the pouch together with the insulating film formed on the lead tab of the battery cell, or by directly heat-sealing the inner surface of the pouch to the inner surface of the pouch. The insulating film is typically a polypropylene (PP) film.

[0008] Pouch sealing seals a specific space within the pouch that holds the electrolyte. When battery cells are repeatedly charged and discharged, gas is generated, increasing the pressure within the pouch. For this reason, pouch sealing requires high strength.

[0009] Meanwhile, when sealing the pouch by thermal fusion, the polypropylene (PP) film melts and spreads to adhere. The polypropylene film not only adheres the pouch, but also isolates the metal layer of the pouch, such as aluminum, from the electrolyte, preventing corrosion of the metal layer and preventing current flow through the pouch, which would otherwise increase resistance.

[0010] The applicant of the present invention has proposed a manufacturing device and a manufacturing method for performing plasma surface treatment on the surface of a pouch during transport through Republic of Korea Patent Application No. 10-2023-0042329 (hereinafter referred to as “prior patent 1”) and Republic of Korea Patent Application No. 10-2023-0046322 (hereinafter referred to as “prior patent 2”).

[0011] Prior patent 1 demonstrates that pouch sealing strength can be increased by irradiating the pouch surface with plasma gas together with a carrier gas. Since the plasma gas is generated prior to irradiation through the plasma head, this is termed indirect plasma.

[0012] Prior patent 2 confirms that by irradiating plasma gas onto the pouch surface, pouch sealing strength can be increased and adhesion strength can be reduced. Since the gas irradiated through the plasma head is converted into plasma and irradiated onto the pouch surface, this is referred to as direct plasma.

[0013] To improve sealing strength or reduce bonding strength through plasma surface treatment, the plasma surface treatment intensity must be appropriate. For example, the desired plasma intensity can be achieved when the pouch transport speed is approximately 60 mm / s.

[0014] Unit pouches, which are the packaging material for a single secondary battery, can be manufactured by cutting pouch sheets transported via a pouch roll into unit lengths. During the actual pouch manufacturing process, the pouch sheet transport speed is approximately 800 mm / s, making it extremely difficult to achieve the desired plasma intensity. This is because the time the pouch surface is exposed to the plasma environment is extremely short.

[0015] Therefore, it is not easy to apply plasma surface treatment to a site where secondary batteries are manufactured by manufacturing unit pouches from pouch rolls, rather than at a site where the pouch rolls themselves are manufactured.

[0016] Through one embodiment of the present invention, it is intended to provide a secondary battery pouch manufacturing device and method capable of applying plasma surface treatment in a continuously performed unit pouch manufacturing process.

[0017] Through one embodiment of the present invention, it is intended to provide a secondary battery pouch manufacturing device and method capable of performing plasma surface treatment using the time during which a forming process for forming a cup on a pouch sheet is performed.

[0018] In one embodiment of the present invention, a plasma device capable of performing plasma treatment at a local location for a desired period of time is provided, thereby preventing waste of plasma material.

[0019] Through one embodiment of the present invention, it is intended to provide a secondary battery pouch manufacturing device and method that can flexibly respond to changes in product size by enabling a plasma head and a guide block to move horizontally.

[0020] Through one embodiment of the present invention, it is intended to provide a secondary battery pouch manufacturing device and method capable of performing plasma treatment at an accurate position by supporting a pouch sheet while a guide block is raised and comes into contact with the outer surface of the cup of the pouch sheet.

[0021] In order to achieve the above-described purpose, according to one embodiment of the present invention, a method for manufacturing a pouch for a secondary battery may be provided, including a transport step of transporting and stopping a pouch sheet from a pouch roll at a predetermined cycle using an unwinder; a forming step of forming a cup in which an electrode assembly is accommodated by forming the pouch sheet in a stopped state after being transported through the transport step; and a surface treatment step of performing plasma surface treatment on the pouch sheet in a stopped state after being transported through the transport step.

[0022] The forming step may be performed on a pouch sheet on which the surface treatment step has been performed, or the surface treatment step may be performed on a pouch sheet on which the forming step has been performed.

[0023] It is preferable that the above plasma surface treatment be performed on the outer region near the rim of the cup where the pouch is sealed by heat pressurization. That is, it is preferable that the plasma surface treatment be performed on the region where the pouch is heat-sealed in a subsequent process.

[0024] The above plasma surface treatment can be performed using a plasma device. The plasma device can include a plasma head and a guide block.

[0025] The plasma head may be provided so as to face the surface on which plasma surface treatment is performed, and the guide block may be provided so as to face the back surface of the surface on which plasma surface treatment is performed. The plasma head may be provided so as to face the guide block.

[0026] Plasma surface treatment can be performed while the above guide block is in contact with and supports the pouch sheet. It is preferable that plasma surface treatment be performed only on a specific portion supported by the above guide block.

[0027] The above manufacturing method is preferably performed as an inline process. Plasma surface treatment is performed only on a local area supported by a guide block while the transport of the pouch sheet is stopped, thereby enabling efficient and accurate plasma surface treatment.

[0028] It is preferable that the above plasma surface treatment is performed only on the upper or lower surface of the pouch sheet that is covered and in contact when sealing the pouch. In other words, it is preferable that the plasma surface treatment is not performed on the surface that forms the outer surface of the pouch in the secondary battery after manufacturing is completed.

[0029] It is preferable that the above plasma surface treatment is also performed on the inner area near the rim of the cup. That is, the plasma surface treatment can also be performed on the area near where the molten polypropylene flows into and adheres in the sealing area.

[0030] The above sealing area is formed on the rim of the cup. Therefore, the sealing area is formed on the outside based on the outer surface of the cup.

[0031] Plasma surface treatment can be performed by supporting the pouch sheet while the guide block is raised and in contact with the outer surface of the cup of the pouch sheet. Accordingly, plasma treatment can be performed at an accurate location. That is, the guide block approaches an accurate location based on the position of the cup and supports the pouch sheet, thereby performing plasma surface treatment.

[0032] The above guide blocks are provided as a pair on the left and right, and the gap between the guide blocks can be controlled to be variable. One guide block and the other guide block can be independently moved horizontally. In addition, the guide blocks can be raised and lowered.

[0033] In the above forming step, two cups arranged in parallel in the width direction of the pouch sheet are formed, and the cups can be formed in a rectangular shape having a short side in the width direction of the pouch sheet and a long side in the length direction of the pouch sheet.

[0034] The sealing on the short side can be called top sealing, and the sealing on the long side can be called side sealing.

[0035] The above plasma surface treatment can be performed on at least one of the outer region of the short side edge and the outer region of the long side edge.

[0036] It is preferable to include a cutting step for cutting the pouch sheet, which has been transported and then stopped through the transport step after the surface treatment step, into unit pouches.

[0037] That is, after the forming process and surface treatment process are performed on the continuously connected pouch sheet, a unit pouch can be manufactured only in the cutting step.

[0038] It is preferable that the above forming step, surface treatment step, and cutting step are performed simultaneously. That is, it is preferable that the forming process, surface treatment process, and cutting process are performed at different locations within the period during which the pouch sheet is stopped after being transported. After the forming process, surface treatment process, and cutting process are all completed, the pouch sheet can be transported again. The pouch sheet can be transported and then stopped for one pitch corresponding to the length of a unit pouch.

[0039] In order to achieve the above-described purpose, according to one embodiment of the present invention, a secondary battery pouch manufacturing device can be manufactured, characterized by including an unwinder that transports and stops at regular intervals to supply a pouch sheet from a pouch roll; a forming device that forms a cup that accommodates an electrode assembly by forming a pouch sheet in a stationary state; and a plasma device that performs surface treatment by irradiating plasma to a pouch sheet in a stationary state.

[0040] The above forming device and plasma device are located at the rear end of the unwinder, and the forming device may be located at the front or rear end of the plasma device.

[0041] The plasma device may include a plasma head that irradiates plasma toward one side of the pouch sheet; and a guide block that supports the other side of the pouch sheet during the plasma irradiation and is provided to be spaced apart from the other side of the pouch sheet when the plasma irradiation is completed.

[0042] The above plasma head and guide block form a pair, and two pairs of the plasma head and guide block may be provided spaced apart from each other in the length direction or width direction of the pouch sheet. That is, one plasma device can perform plasma surface treatment on both sides of the main body.

[0043] The above cup may include a cutting device for cutting the formed and surface-treated pouch sheet into unit pouches.

[0044] It is preferable that the forming device, plasma device and cutting device operate at different positions while the pouch sheet is stationary.

[0045] The pouch sheet may include a feeding device that supports the pouch sheet when cutting the pouch sheet using the cutting device and moves the pouch sheet to the cutting position of the cutting device when cutting is completed.

[0046] In order to achieve the above-described object, according to one embodiment of the present invention, a pouch plasma device for a secondary battery can be provided, including: a plasma head provided on one upper side and the other side of a pouch sheet, respectively, to irradiate plasma on the surface of the pouch sheet; and a guide block provided on one lower side and the other side of the pouch sheet, respectively, to face the plasma head, wherein the guide block is positioned to be spaced apart from the lower surface of the pouch sheet when the pouch sheet is transported, and is provided to rise to support the lower surface of the pouch sheet when the pouch sheet is stopped, and the plasma head is characterized in that it irradiates plasma to the upper surface of the pouch sheet in a state where the guide block supports the lower surface of the pouch sheet.

[0047] It is preferable that the above plasma device be equipped to perform surface treatment by irradiating plasma to a portion of the surface of the pouch.

[0048] The plasma head may be provided to descend when the pouch sheet is stopped and approach the lower surface of the pouch sheet.

[0049] It is preferable that the gap between the plasma heads and the gap between the guide blocks be adjustable.

[0050] Therefore, it is preferable that the plasma head and guide block be equipped with vertical and horizontal movements, allowing for flexible response even when the cup size changes.

[0051]

[0052] Through one embodiment of the present invention, a secondary battery pouch manufacturing device and method can be provided that can apply plasma surface treatment in a continuously performed unit pouch manufacturing process.

[0053] Through one embodiment of the present invention, a secondary battery pouch manufacturing device and method can be provided that can perform plasma surface treatment using a forming process period for forming a cup on a pouch sheet.

[0054] Through one embodiment of the present invention, a plasma device capable of performing plasma treatment at a local location for a desired period of time can be provided, thereby preventing waste of plasma material.

[0055] Through one embodiment of the present invention, it is possible to provide a secondary battery pouch manufacturing device and method that can flexibly respond to changes in product size by enabling a plasma head and a guide block to move horizontally.

[0056] Through one embodiment of the present invention, a secondary battery pouch manufacturing device and method can be provided that can perform plasma treatment at an accurate position by supporting a pouch sheet while a guide block is raised and comes into contact with the outer surface of the cup of the pouch sheet.

[0057] Through one embodiment of the present invention, a method for manufacturing a pouch for a secondary battery that can be applied to both indirect plasma surface treatment and direct plasma surface treatment can be provided.

[0058] Figure 1 is a plan view of a unit pouch.

[0059] Figure 2 is a flow chart of a pouch manufacturing method according to an embodiment of the present invention.

[0060] Figure 3 is a flowchart of a pouch manufacturing method according to another embodiment of the present invention.

[0061] Figure 4 illustrates the appearance before forming in a pouch manufacturing device according to one embodiment of the present invention.

[0062] FIG. 5 illustrates the appearance during forming in a pouch manufacturing device according to one embodiment of the present invention.

[0063] Figure 6 illustrates the appearance after forming in a pouch manufacturing device according to one embodiment of the present invention.

[0064] FIG. 7 illustrates the feeding and cutting of a pouch through a feeding device and a cutting device in a pouch manufacturing device according to one embodiment of the present invention.

[0065] Figure 8 is a perspective view of a plasma device applicable to a pouch manufacturing device according to an embodiment of the present invention.

[0066] Fig. 9 is a side view of the plasma device illustrated in Fig. 8.

[0067] Hereinafter, a pouch manufacturing device for a secondary battery according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0068] First, a unit pouch (10) that can be manufactured through an embodiment of the present invention will be described in detail with reference to FIG. 1. FIG. 1 is a plan view of the unit pouch and can also be said to be an expanded view of the pouch case.

[0069] The pouch sheet can be formed by providing polypropylene layers on the outer and inner surfaces of an aluminum foil. That is, when forming a sealing material using the pouch sheet, the outer polypropylene surface forms the outer surface of the pouch, and the inner polypropylene surface forms the outer surface of the pouch, preventing the aluminum foil from being exposed to external air or internal electrolyte. Of course, the resin layers on the outer and inner surfaces may be made of different materials.

[0070] The pouch sheet can be continuously transported and supplied through a pouch roll and cut into a certain length to be manufactured into a unit pouch (10). That is, both ends of the unit pouch (10) can be formed through a cutting line (18) cut from the pouch sheet.

[0071] The pouch sheet is moved along the x-axis by the length of the unit pouch and then cut while stationary, and the width of the unit pouch can be the same as the width of the pouch roll (y-axis). Therefore, there is no need to separately cut the width of the pouch sheet to manufacture the unit pouch. Of course, additional cutting can be performed after the pouch case is manufactured.

[0072] As illustrated, a portion of the edge surfaces (13, 14, 15, 16) of the unit pouch (10) may form a sealing region (11). A cell region (12) in which battery cells are tightly pressed and electrolyte is filled may be formed in an inner region of the sealing region (11). Specifically, a portion of the edge surfaces (13, 14, 15, 16), for example, a region surrounding a molded cup (12A, 12B), may be referred to as a sealing region. The cups (12A, 12B) may be formed by being recessed in the z-axis, which is perpendicular to the pouch surface.

[0073] Here, the sealing area can be said to be an area where the pouch surfaces are sealed by heat and pressure while the pouch surfaces are in contact with each other.

[0074] A folded portion (17) may be formed in the middle of the cell area (12), and after a battery cell is installed in the cell area (12) on either side of the folded portion, the upper and lower cell areas (12) and the sealing area (11) may be overlapped with the folded portion as the center. Thereafter, pouch sealing is performed through heat fusion of the sealing area (11). The pouch sheet after pouch sealing is completed may be referred to as a pouch case.

[0075] The above cell area (12) is formed by cups (12A, 12B) formed by forming. For example, the cups (12A, 12B) can be formed by denting the pouch surface with a punch.

[0076] The shape of the cups (12A, 12B) corresponds to the shape of the electrode assembly to be accommodated, and is typically a square shape. Fig. 1 illustrates an example in which two cups are formed vertically. In addition, a cup having left and right short sides (12a, 12b) and upper and lower long sides (12c, 12d) is illustrated. Here, the upper, lower, left and right line segments (12a, 12b, 12c, 12d) of the cups (12A, 12B) can be considered as the rim of the cups.

[0077] In the absence of a fold, the unit pouch sheet (10) may be the upper and lower casings of the pouch casing. Since the upper and lower casings are positioned to face each other and then sealed, the sealing area (11) appears in the same manner. However, in the presence of a fold, sealing is unnecessary due to the fold, so sealing is performed in three segments, and in the absence of a fold, sealing may be performed in four segments.

[0078] The outer region near the rim (12a, 12b, 12c, 12d) of the above cup may be referred to as a sealing region (11a, 11b, 11c, 11d), and the inner region of the sealing region may be referred to as a bonding region (19). Of course, both the sealing region and the bonding region may be located outside the rim of the cup, and in this case, the sealing region may be located further outside the rim of the cup than the bonding region. The sealing region is a region where sealing is performed by directly applying heat and pressure, and the bonding region may be a region into which molten polypropylene flows in the sealing region. The bonding region outside the sealing region is unrelated to the problem of sealing strength, and the sealing strength of the bonding region inside the sealing region may be a problem.

[0079] Meanwhile, sealing near the upper and lower long sides (12c, 12d) can be called side sealing, and sealing near the left and right short sides (12a, 12b) can be called top sealing. In side sealing, sealing is performed while the pouches are in direct contact with each other, and in top sealing, sealing can be performed by interposing an electrode lead between the pouches.

[0080] Accordingly, plasma surface treatment can be performed in the sealing area and / or the bonding area where top sealing is performed, and plasma surface treatment can be performed in the sealing area and / or the bonding area where side sealing is performed.

[0081] FIGS. 4 to 6 illustrate examples of plasma surface treatment performed in a sealing area and / or an adhesion area in a top seal.

[0082] Specifically, FIG. 4 illustrates a state in which a pouch sheet is being transported or transport is stopped, FIG. 5 illustrates a state in which a forming process, a surface treatment process, and a cutting process are performed while the pouch sheet is stopped, and FIG. 6 illustrates a state in which a forming process, a surface treatment process, and a cutting process are completed while the pouch sheet is stopped.

[0083] According to the present embodiment, a method and device for manufacturing a pouch for a secondary battery can be provided, which can improve sealing strength by subjecting at least one of a top sealing area (11a, 11b) and a side sealing area (11c, 11d) to plasma surface treatment.

[0084] In addition, according to the present embodiment, a method and device for manufacturing a pouch for a secondary battery can be provided, which can reduce the bonding strength by subjecting the bonding area near at least one of the top sealing area (11a, 11b) and the side sealing area (11c, 11d) to plasma surface treatment.

[0085] In particular, according to the present embodiment, plasma surface treatment can be performed using a conventional unit pouch manufacturing process. Furthermore, according to the present embodiment, a manufacturing method and device can be provided that can prevent an increase in manufacturing time for plasma surface treatment by performing plasma surface treatment during a conventional unit pouch manufacturing process.

[0086] Hereinafter, a manufacturing method and a manufacturing device according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 6.

[0087] As illustrated in FIG. 2, according to one embodiment of the present invention, a method for manufacturing a pouch for a secondary battery can be provided, including a transfer step (S10), a forming step (S20), and a surface treatment step (S30) of a pouch sheet.

[0088] The transport step (S10) of the pouch sheet can be said to be a step of transporting and stopping the pouch sheet (2) from the pouch roll (1) at a certain cycle or at a certain pitch using the unwinder (20) to supply it.

[0089] As shown in Fig. 4, a pouch roll (1) is mounted on an unwinder (20), and as the unwinder rotates, pouch sheets (2) can be continuously supplied as the pouch roll is unwound.

[0090] A flat pouch sheet (2) can be formed through a forming device (30). In particular, it can be formed (S20) to form a cup (12A, 12B) into which an electrode assembly is inserted.

[0091] The forming device (30) can form a cup through a lower mold (32) and an upper mold (31). The lower mold (32) can be referred to as a die, and the upper mold (31) can be referred to as a punch. A stripper for fixing the pouch sheet (2) during the forming process can be additionally provided.

[0092] The cups (12A, 12B) are formed by being sunken downward from the surface of the pouch sheet (2) and have a space into which the electrode assembly is inserted and received. In addition, it is preferable that the cups (12A, 12B) are formed in the central portion of the pouch sheet (2).

[0093] The forming process, i.e., the forming step (S20), can be performed while the pouch sheet is inserted between the lower mold (32) and the upper mold (31) and in a stationary state. Therefore, for the forming process to be performed, the transport of the pouch sheet supplied through the unwinder (20) must be temporarily stopped. Then, once the forming process is completed, the transport of the pouch sheet can be resumed.

[0094] Therefore, it is preferable that the transport step (S10) of the pouch sheet be performed by repeatedly transporting and stopping the pouch sheet at a certain cycle or at a certain pitch.

[0095] After the pouch sheet is formed through the forming device (30), it can be transferred to the next process. Specifically, a surface treatment process of the pouch sheet can be performed after the forming process.

[0096] The surface treatment step (S30) can be defined as a process for surface modification by irradiating plasma onto the pouch surface. As disclosed in the prior art, direct plasma surface treatment or indirect plasma surface treatment can be performed.

[0097] A plasma device (40) may be provided for plasma surface treatment, and it is preferable that the plasma device (40) be provided on a path along which the pouch sheet is transported.

[0098] In the transport step (S10), the pouch sheet is repeatedly transported and stopped. At this time, the transport speed of the pouch sheet is very fast in order to increase the manufacturing efficiency of the pouch sheet. Therefore, in order to perform plasma surface treatment at an appropriate intensity, a plasma surface treatment device (40) with a very large capacity is required. This is because the faster the transport speed of the pouch sheet, the shorter the time of exposure to plasma. In addition, it is inefficient to perform plasma treatment while the pouch sheet is being transported. This is because since plasma treatment is performed on the entire pouch sheet, plasma treatment may also be performed on unnecessary parts. Therefore, it is not easy to selectively perform plasma treatment only on a specific part that requires plasma treatment.

[0099] According to one embodiment of the present invention, the plasma surface treatment process can be linked to the pouch forming process, so that the surface treatment process can be performed during the forming process. Of course, the forming process can be performed during the surface treatment process. In particular, the point in time when the transport of the pouch sheet is stopped for the forming process can be utilized to perform the surface treatment of the pouch sheet in a stopped state at the same point in time.

[0100] Specifically, a forming process is performed on a pouch sheet that has been transported and then held stationary through a transport step using a forming device. Furthermore, a surface treatment process is performed on a pouch sheet that has been transported and held stationary through a transport step using a plasma device. The forming process and the surface treatment process can be performed at different locations. In other words, the forming device and the plasma device can be separated from each other.

[0101] Since the plasma surface treatment process is performed on a stationary pouch sheet, plasma surface treatment can be precisely performed on only specific areas. Consequently, the efficiency of the plasma surface treatment can be increased.

[0102] As illustrated in Fig. 4, a plasma device (40) may be provided at the rear end of the forming device (30). That is, the forming device (30) and the plasma device (40) are provided on the path along which the pouch sheet is transported, and the pouch sheet (2) on which the forming process has been completed may be supplied to the plasma device (40) and subjected to surface treatment. At this time, it is preferable that the transport and stop of the pouch sheet be performed simultaneously at all positions along the pouch sheet movement path. That is, the pouch sheet continuously repeats movement and stop from the movement start position of the pouch sheet (for example, the unwinder (20)) to the movement end position (for example, the feeding device (60)).

[0103] The plasma device (40) may include a plasma head (46) and a guide block (47).

[0104] An AC power source may be applied between the plasma head (46) and the guide block (47) to ignite plasma between the two, thereby generating plasma. Through this plasma, local surface treatment can be performed on the surface of the pouch. This plasma surface treatment can be referred to as direct plasma surface treatment.

[0105] Plasma ignition is performed in a separate area, plasma gas is supplied to the pouch surface through a plasma head (46), and a guide block (47) can perform the function of supporting the pouch. This plasma surface treatment can be referred to as indirect plasma surface treatment.

[0106] In both direct plasma surface treatment and indirect plasma surface treatment, the guide block (47) performs the function of supporting the pouch sheet to be surface treated, and plasma surface treatment can be performed on a specific portion of the pouch sheet supported by the guide block (47). In conclusion, the guide block (47) can be said to be a configuration for specifying an area where plasma surface treatment is performed.

[0107] As illustrated in Fig. 4, while the pouch sheet (2) is being moved, the pouch sheet (2) is separated from the forming device (30) and the plasma device (40). That is, the forming device (30) and the plasma device (40) can be positioned in detail so as not to impede the movement of the pouch sheet (2).

[0108] As shown in Fig. 5, the forming device (30) can perform a forming process and the plasma device (40) can perform a surface treatment process while the pouch sheet (2) is stationary.

[0109] And, when the forming process, surface treatment process, and cutting process are completed, as shown in Fig. 6, the forming device, plasma device, and cutting device return to their original positions, and the pouch sheet can be moved by one pitch and then stopped again.

[0110] The forming process may include a process in which at least one of the upper mold (31) and the lower mold (32) moves to form a cup, and the upper mold (31) and the lower mold (32) return to their original positions. Accordingly, the period from when the mold starts moving until it returns to its original position may be referred to as a forming period.

[0111] Accordingly, the pouch sheet (2) before the forming process has only a horizontal surface (2a), and after the forming process, the horizontal surface (2a) is maintained at both ends in the width direction of the pouch sheet (2), and the central portion is sunken by the cups (12A, 12B).

[0112] Likewise, the surface treatment process may include a process in which the plasma head (46) and the guide block (47) move to perform plasma surface treatment, and the plasma head (46) and the guide block (47) return to their original positions. Accordingly, the period from when the plasma device (40) starts moving until it returns to its original position may be referred to as the surface treatment period.

[0113] Here, the forming period and surface treatment period may be the same, and some periods may be somewhat longer than others. Therefore, the suspension period of the pouch sheet (2) may be determined to suit the longer period.

[0114] The pouch sheet (2) for which the forming process and surface treatment process have been completed can then be cut into unit pouches (10). Cutting of the pouch sheet (2) can be performed using a cutting device (50). That is, the cutting process or cutting step (S50) can be performed using the cutting device. The cutting device (50) can include an upper cutter (51) and a lower cutter (52). The upper cutter and the lower cutter can approach the pouch sheet to cut the pouch sheet, and can move away from the pouch sheet so as not to interfere with the transport of the pouch sheet after cutting.

[0115] When cutting is performed from the pouch sheet (2) into unit pouches (10), the pouch sheet (2) is no longer in a continuous state. Therefore, in order to cut the pouch sheet (2), the pouch sheet (2) must be fixed. In addition, the cut pouch must be transported. For this purpose, a feeding device (60) may be provided.

[0116] The feeding device (60) can support the pouch sheet (2) on both sides of the cutting position of the pouch sheet (2) and, after cutting is completed, pull the pouch sheet (2) to move the pouch sheet (2) to the cutting position. That is, pulling the pouch sheet (2) to move the pouch sheet (2) can be performed synchronously with transporting the pouch sheet (2) through the unwinder (20).

[0117] The feeding device (60) may include a gripper (65) that holds both ends of the pouch sheet (2), i.e., a horizontal surface (2a), and a main body (62) equipped with the gripper. The main body (62) is equipped to move back and forth along the length of the unit pouch, and the main body (62) can be moved along a guide (61) equipped with a guide rail.

[0118] Accordingly, the cutting step (S50) may be performed after the feeding step (S40) is performed. Of course, depending on the point of view, it may also be said that the feeding step (S40) is performed after the cutting step (S50).

[0119] Details of the feeding device (60) and cutting device (50) will be described later.

[0120] In FIGS. 4 and 6, an example is illustrated in which the pouch sheet (2) is transported on the same plane and the forming process and surface treatment process are performed while the pouch sheet (2) is in a horizontal state. In this case, the forming device (30) and the plasma device (40) can move in the vertical direction of the pouch sheet (2) to perform forming and surface treatment. In other words, the forming and surface treatment can be performed by moving in the vertical direction.

[0121] Unlike the drawing, the pouch sheet (2) may be transported while forming multiple planes rather than the same plane. In this case, the pouch sheet (2) may be transported while being bent in a vertical direction and then transported in a horizontal direction again. In this case, the forming device (30) and the plasma device (40) may move in the vertical direction of the pouch sheet (2) to perform forming and surface treatment. That is, the forming and surface treatment may be performed by moving in the left and right directions.

[0122] Meanwhile, FIGS. 2, 4, and 6 illustrate examples in which a surface treatment step is performed after a forming step. According to the present embodiment, as illustrated in FIG. 3, the forming step may be performed after the surface treatment step. That is, the positions of the forming device and the plasma device may be interchanged.

[0123] After cup forming is performed, the sealing area in the pouch sheet can be visually distinguished. That is, the sealing area can be distinguished as the area surrounding the cup, because the sealing area can be defined relatively to the cup.

[0124] The movement of the pouch sheet can be stopped after the length of the unit pouch has been reached. Therefore, even before cup forming is performed, the cup forming area and its surrounding area on the pouch sheet can be preset. This is because the movement and stopping of the pouch sheet can be repeated for a certain length. Therefore, the forming step can be performed only after plasma surface treatment is performed in a certain area.

[0125] Meanwhile, based on the unit pouch (10), side sealing can be performed in the sealing areas (11c, 11d) on both sides in the width direction, and top sealing can be performed in the sealing areas (11a, 11b) on both sides in the length direction.

[0126] The sealing area is relatively narrow and long. Furthermore, the sealing areas are formed on both sides of the cups (12A, 12B). Therefore, it is not easy to surface-treat both sealing areas using a single plasma head.

[0127] Therefore, it is desirable to surface-treat both sealing areas in the side sealing or both sealing areas in the top sealing using one plasma device (40). Of course, one plasma device (40) may be equipped with two plasma heads (46).

[0128] Figures 4 to 6 illustrate a plasma device (40) that surfaces both sealing areas in a top sealing. However, by rotating the plasma device (40) by 180 degrees, a plasma device that surfaces both sealing areas in a side sealing can be implemented.

[0129] Therefore, by sequentially arranging two plasma devices (40), the sealing area in the top sealing can be surface-treated and then the sealing area in the side sealing can be surface-treated. Of course, the sealing area in the side sealing can be surface-treated and then the sealing area in the top sealing can be surface-treated. That is, the surface treatment step (S30) can include a first surface treatment step (S31) and a second surface treatment step (S32).

[0130] Details of the plasma device (40) will be described later.

[0131] Ultimately, according to the present embodiment, forming may be performed after surface treatment, or after forming. Furthermore, surface treatment may be performed in multiple stages. In either case, it is preferable that the surface treatment be performed on a path in which the pouch sheet is continuously transported and stopped.

[0132] In addition, the forming process, surface treatment process, and cutting process are performed while the pouch sheet is stationary, and the forming process, surface treatment process, and cutting process can be performed simultaneously by changing the position.

[0133] As shown in Fig. 7, the pouch sheet can be cut into unit pouches by the cutting device (50) and the feeding device (60), and the unit pouches can be transferred to a subsequent process.

[0134] The main body (62) of the feeding device (60) may be provided to reciprocate in units of one pitch, and the main body (62) may reciprocate along the guide rail (60). A gripper (65) may be provided on the main body (62) of the feeding device (60). The main body (62), the guide rail (60), and the gripper (65) may be provided as a pair on both sides of the pouch sheet (2).

[0135] The gripper (65) can pull and transport the pouch sheet by one pitch while holding both ends of the pouch sheet (2) before cutting. Thereafter, the pouch sheet (2) can be supported by the gripper (65) while being held, and the pouch sheet can be cut through the cutting device (50). At this time, a continuous pouch sheet is still positioned at the front end of the cutting device (50), and the unit pouch manufactured after cutting is positioned at the rear end. The unit pouch can be transported to a subsequent process, for example, an assembly process, through a transport device such as a conveyor.

[0136] After the unit pouch is formed by cutting, the gripper (65) no longer holds the unit pouch, but returns to its original position to hold the pouch sheet.

[0137] The gripper (65) may include an upper gripper (63) and a lower gripper (64), and may perform a gripping function by repeatedly closing and opening the gap between the two. The feeding function may be performed through the forward and backward reciprocating movement of the gripper.

[0138] As illustrated in FIGS. 8 and 9, the plasma device (40) may include a base (41) and a main body (42). A plasma head (46) and a guide block (47) may be provided on the left and right sides of the main body (42), respectively. That is, a pair of plasma heads on the left and right sides and a pair of guide blocks on the left and right sides may be provided.

[0139] The plasma head (46) is provided to irradiate plasma gas to one side (e.g., the upper side) of the pouch sheet, and the guide block (47) may be provided to support the other side (e.g., the lower side) of the pouch sheet.

[0140] The gap between the plasma head (46) and the guide block (47) can be formed to be repeatedly narrowed and widened. That is, during plasma irradiation, the plasma head (46) can be positioned to approach the upper surface of the pouch sheet, and the guide block (47) can be positioned to support the lower surface of the pouch sheet. Thereafter, when the plasma irradiation is completed, the plasma head and the guide block can be positioned to move vertically away from the pouch sheet. In this state, the pouch sheet can move one pitch again.

[0141] The guide block (47) is provided to move up and down through a piston (48), and the plasma head (46) can also be provided to move up and down through a piston (45).

[0142] The spacing between the plasma heads (46) and the spacing between the guide blocks (47) and the guide blocks (47) can be preset, and these spacings can be set according to the size of the cups (12A, 12B). This is because when the size and shape of the cup are determined, the area to be subjected to plasma surface treatment is determined accordingly.

[0143] The above gap can be varied to flexibly cope with changes in the width of the pouch sheet or the size of the cup. That is, the distance between the plasma head (46) and the guide block (47) with respect to the main body (42) can be adjusted. To this end, the plasma head (45) can be coupled to the main body (42) through the support bracket (45) and the connecting bracket (44). The gap between the plasma heads can be adjusted by adjusting the gap between the support bracket (45) and the main body (42) through the connecting bracket (44).

[0144] Likewise, the distance between the guide blocks (47) can also be adjusted. In particular, the upper plasma head (46) and the lower guide block (47) are provided to face each other, and the horizontal movement of one can be linked to the horizontal movement of the other.

[0145] The plasma-irradiated area can be narrow and long. The width of the plasma-irradiated area can be determined based on the width of the thermal bonding, and the length of the plasma-irradiated area can be determined based on the length of the thermal bonding. As the cup size varies, the width of the thermal bonding does not vary significantly, but the length of the thermal bonding can vary significantly. Therefore, the plasma-irradiated area can have a long rectangular shape.

[0146] The plasma irradiation intensity that can be generated from a single plasma device (40) is limited. Therefore, one plasma device (40) may perform plasma surface treatment on the left and right or top and bottom ends of the cup, and another plasma device (40) may perform plasma surface treatment on the remaining area. In this case, the other plasma device (40) may be provided in a state of being rotated 180 degrees.

[0147] Meanwhile, it is desirable that the pouch sheet (2) that is repeatedly transported and stopped between the unwinder (20) and the feeding device (60) does not sag downward and forms a horizontal plane. In other words, it is necessary that an appropriate tension be applied to the pouch sheet.

[0148] For example, a plurality of support rolls may be provided on the transport path of the pouch sheet (2). The support rolls may be provided to support the entire width of the pouch sheet before forming the pouch sheet. In addition, the support rolls may be provided to support only both ends of the width of the pouch sheet after forming the pouch sheet. This is because even after forming, both ends of the width of the pouch sheet still form a horizontal plane (2a).

[0149] In addition, for plasma surface treatment, it is desirable to supply plasma perpendicularly to the pouch surface. Therefore, the pouch sheet needs to be supported on both sides to maintain a flat surface. To this end, the plasma device (40) may include pouch support members (49) at each end. Of course, the distance between the pouch support members may be adjusted.

[0150] It is preferable that the pouch support member (49) be provided to support both ends of the pouch sheet while simultaneously allowing movement of the pouch sheet. That is, it is preferable that the pouch support member (49) be provided to support only both end portions of the pouch sheet so as not to interfere with the cup formed in the central portion of the pouch sheet.

[0151] Meanwhile, the plasma head and the guide block are arranged to face each other. Therefore, when the plasma device is installed horizontally, the plasma head and the guide block are moved vertically. To adjust the plasma surface treatment position, the plasma head and the guide block may be arranged to move horizontally. In this case, it is desirable that the horizontal movement of the plasma head and the horizontal movement of the guide block be linked. This is because it is desirable to accurately maintain the opposing relationship between the two.

[0152] As described in the detailed description of the invention.

Claims

1. A transport step that transports and stops pouch sheets from a pouch roll at regular intervals using an unwinder to supply them; A forming step for forming a cup that accommodates an electrode assembly by forming a pouch sheet that has been stopped after being transported through the above transport step; and A method for manufacturing a pouch for a secondary battery, comprising a surface treatment step of performing plasma surface treatment on a pouch sheet in a stationary state after being transported through the above transport step.

2. In paragraph 1, A method for manufacturing a pouch for a secondary battery, characterized in that the forming step is performed on a pouch sheet on which the surface treatment step has been performed.

3. In paragraph 1, A method for manufacturing a pouch for a secondary battery, characterized in that the surface treatment step is performed on a pouch sheet on which the forming step has been performed.

4. In paragraph 1, The above plasma surface treatment is performed through a plasma device including a plasma head and a guide block that supports the pouch sheet and faces the plasma head. A method for manufacturing a pouch for a secondary battery, characterized in that the plasma surface treatment is performed in a state where the outer area (sealing area) near the rim of the cup is supported by the guide block.

5. In paragraph 4, A method for manufacturing a pouch for a secondary battery, characterized in that the plasma surface treatment is performed only on the upper or lower surface of the pouch sheet that is covered and in contact when sealing the pouch.

6. In paragraph 5, A method for manufacturing a pouch for a secondary battery, characterized in that the plasma surface treatment is also performed on an inner area (attachment area) near the rim of the cup.

7. In any one of paragraphs 1 to 6, A method for manufacturing a pouch for a secondary battery, characterized in that in the forming step, two cups are formed in parallel in the width direction of the pouch sheet, and the cups are formed in a rectangular shape having a short side in the width direction of the pouch sheet and a long side in the length direction of the pouch sheet.

8. In paragraph 7, A method for manufacturing a pouch for a secondary battery, characterized in that the plasma surface treatment is performed on at least one of the outer region of the short side edge and the outer region of the long side edge.

9. In any one of paragraphs 1 to 6, A method for manufacturing a pouch for a secondary battery, characterized in that it includes a cutting step for cutting a pouch sheet in a stationary state after being transported through the transport step into unit pouches after the surface treatment step.

10. In paragraph 9, A method for manufacturing a pouch for a secondary battery, characterized in that the forming step, surface treatment step, and cutting step are performed simultaneously while the transport of the pouch sheet is stopped.

11. An unwinder that transports and stops pouch sheets from a pouch roll at regular intervals to supply them; A forming device for forming a cup that accommodates an electrode assembly by forming a stationary pouch sheet; and A secondary battery pouch manufacturing device characterized by including a plasma device that performs surface treatment by irradiating plasma on a stationary pouch sheet.

12. In paragraph 11, A secondary battery pouch manufacturing device characterized in that the forming device and plasma device are located at the rear end of the unwinder, and the forming device is located at the front or rear end of the plasma device.

13. In paragraph 12, The above plasma device, A plasma head that irradiates plasma toward one side of the above pouch sheet; and A secondary battery pouch manufacturing device characterized by including a guide block that supports the other side of the pouch sheet during the plasma irradiation and is provided to be spaced apart from the other side of the pouch sheet when the plasma irradiation is completed.

14. In paragraph 13, A secondary battery pouch manufacturing device characterized in that the plasma head and guide block form a pair, and two pairs of the plasma head and guide block are provided spaced apart from each other in the length direction or width direction of the pouch sheet.

15. In any one of paragraphs 11 to 14, A secondary battery pouch manufacturing device characterized by including a cutting device that cuts a pouch sheet formed with the cup and surface-treated into unit pouches.

16. In paragraph 15, A secondary battery pouch manufacturing device characterized in that the forming device, plasma device, and cutting device operate at different positions while the pouch sheet is stationary.

17. In paragraph 15, A secondary battery pouch manufacturing device characterized by including a feeding device that supports the pouch sheet when cutting the pouch sheet through the cutting device and moves the pouch sheet to the cutting position of the cutting device when cutting is completed.

18. A plasma head provided on each of the upper side and the other side of the pouch sheet to irradiate plasma onto the surface of the pouch sheet; and It includes a guide block provided on each of the lower side and the other side of the pouch sheet and provided to face the plasma head, The above guide block is positioned apart from the lower surface of the pouch sheet when the pouch sheet is transported, and is provided to rise when the pouch sheet is stopped to support the lower surface of the pouch sheet. A pouch plasma device for a secondary battery, characterized in that the plasma head irradiates plasma to the upper surface of the pouch sheet while the guide block supports the lower surface of the pouch sheet.

19. In paragraph 18, A pouch plasma device for a secondary battery, characterized in that the plasma head descends when the pouch sheet is stopped and approaches the lower surface of the pouch sheet.

20. In paragraph 18, A pouch plasma device for a secondary battery, characterized in that the gap between the plasma heads and the gap between the guide blocks are adjustable.

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