Pouch-type secondary battery and apparatus for bending pouch wings of a pouch-type secondary battery

Abstract

The present invention relates to a pouch-type battery cell, a device for folding pouch wings of a battery cell, and a method for folding pouch wings of a battery cell. Specifically, the invention relates to a pouch-type battery cell, a device for folding pouch wings of a battery cell, and a method for folding pouch wings of a battery cell that can improve the insulation resistance performance of the battery cell by preventing and eliminating cracks in the sealing portion of the pouch wings by heating and bending the pouch wings while heating the sealing portion of the pouch wings of the battery cell.

Description

Technology Field

[0001] The present invention relates to a pouch-type battery cell, a device for folding pouch wings of a battery cell, and a method for folding pouch wings of a battery cell. More specifically, the invention relates to a pouch-type battery cell, a device for folding pouch wings of a battery cell, and a method for folding pouch wings of a battery cell that can improve the insulation resistance performance of a battery cell by preventing and eliminating cracks in the sealing portion of the pouch wings by heating and bending the pouch wings while heating the sealing portion of the pouch wings of the battery cell. Background Technology

[0002] Secondary batteries typically refer to lithium secondary batteries, which are batteries containing a high-molecular-weight electrolyte that generate current through the movement of lithium ions, and secondary battery pouches are used as outer packaging materials for such batteries.

[0003] Figure 1 schematically illustrates the general structure of a pouch-type secondary battery as an exploded perspective view.

[0004] Referring to FIG. 1, a pouch-type secondary battery (10) is configured to include an electrode assembly (13), electrode tabs (14, 15) extending from the electrode assembly (13), electrode leads (16, 17) welded to the electrode tabs (14, 15), and a pouch (12) for the secondary battery that accommodates the electrode assembly (13).

[0005] The electrode assembly (13) is a power generation element in which a positive electrode and a negative electrode are sequentially stacked with a separator interposed therein, and is formed in a stacked or stacked / folded structure. The electrode tabs (14, 15) extend from each electrode plate of the electrode assembly (13).

[0006] The electrode leads (16, 17) are each electrically connected to a plurality of electrode tabs (14, 15) extending from each electrode plate, for example, by welding, and a portion of them is exposed to the outside of the secondary battery pouch (12). In addition, an insulating film (18) is attached to a portion of the upper and lower surfaces of the electrode leads (16, 17) to increase the sealing degree with the secondary battery pouch (12) and simultaneously secure an electrical insulation state.

[0007] The pouch (12) for the secondary battery is made of an aluminum laminate sheet and provides a space to accommodate the electrode assembly (13), and has an overall pouch shape.

[0008] A pouch for a secondary battery is configured with an interposed aluminum film to protect a battery cell, which consists of an electrode assembly and an electrolyte introduced into the interior through a subsequent process, and to complement the electrochemical properties of the battery cell and enhance heat dissipation.

[0009] To protect the battery cell from external impact, the aluminum film is formed by an outer layer of a functional polymer film such as polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN), nylon resin, or liquid crystal polymer (LCP).

[0010] In the outer surface portion of the pouch, the upper pouch and the lower pouch are joined by heat fusion or the like, and an adhesive layer is formed between the lower surface of the upper pouch and the upper surface of the lower pouch for mutual adhesion using a polyolefin such as polyethylene (PE), casted polypropylene (cPP), or polypropylene (PP), or a copolymer thereof.

[0011] These pouch-type batteries undergo a step of housing an electrode assembly in a laminate sheet, injecting an electrolyte, and sealing it by heat fusion, etc., and then undergo a process of housing the battery cell in a folding device to vertically fold the outer surface or the heat-fused portion (sealing portion) and pressurize the sealing portion to ensure it adheres to the side wall of the housing.

[0012] However, when the sealing portion is vertically bent using a bending device, there is a problem in that the bent area returns to its original state over time, causing defects in the battery cell dimension design and requiring the work to be repeated.

[0013] This invention relates to a battery cell bending device including a heating member according to Korean Published Patent No. 10-2015-0035123. A method for bending the outer surface of a battery cell using a battery cell bending device according to the prior art is briefly described as follows.

[0014] FIG. 2 is a flowchart illustrating a folding method for folding pouch wings of a battery cell according to the prior art, and FIG. 3 illustrates the state of the sealing portion after folding the pouch wings according to the prior art.

[0015] As shown in FIG. 2, a battery cell is placed on a battery cell folding device and the outer surface of the battery cell is folded. During the heat fusion process, a pouch wing (12a) is formed in the direction of the outer surface of the storage portion of the battery cell (10), and this process is a process of folding the pouch wing (12a).

[0016] The battery cell (10) is mounted on a base plate (20) formed in a battery cell bending device, and the bending portion of the pouch wing (12a) is fixed by bending guides (21, 22), and the pressure rollers (31, 32) move downward to bend the pouch wing (12a) vertically downward.

[0017] At this time, the pouch wing (12a) of the battery cell (10) is bent and heated at the same time by heating members (41, 42) mounted on adjacent parts of the pressure rollers (31, 32) and adheres to the side wall of the battery cell.

[0018] A battery cell folding device including a heating member according to Korean Published Patent No. 10-2015-0035123 solves the problem of defects in battery cell dimensional design that may occur as the folded portion restores over time by using the heating member to vertically fold the outer surface of the battery cell and press it against the side wall of the storage portion.

[0019] Since the sidewalls of the battery cell are not heated using the above method, heat is not sufficiently supplied to the sealing area of ​​the battery cell, resulting in unmelted sealing areas. Consequently, clusters of microcracks may form in the sealing area of ​​the pouch flaps, raising concerns about insulation failure.

[0020] Insulation resistance refers to the degree of insulation between the aluminum pouch and the cell within the cell pouch. As illustrated in FIG. 3, insulation failure occurs due to electrical conduction between the aluminum pouch and the cell caused by a cluster of micro-cracks (12c) in the sealing portion (12b) of the pouch wing. Here, the sealing portion (12b) refers to the area where the pouch wing is attached with a weak adhesive force before sealing.

[0021] If a large number of battery cells with defective insulation resistance are discharged, equipment shutdown is anticipated due to detection by the Manbae sensor, raising concerns about resulting production losses. Here, the Manbae sensor identifies and discharges battery cells as defective if they fail to meet the specifications set by the equipment during manufacturing; if the discharge port becomes full due to these discharged defective cells, an alarm is triggered and the equipment stops.

[0022] Meanwhile, when the sealing portion of the pouch flap in the battery cell is fixed with tape and positioned adjacent to the electrode assembly, a difference in full width inevitably occurs between the tape-attached portion and the tape-unattached portion, resulting in process loss. The problem to be solved

[0023] The present invention aims to provide a pouch-type battery cell, a device for bending pouch wings of a battery cell, and a method for bending pouch wings of a battery cell, which can improve the insulation resistance performance of a battery cell by preventing and eliminating cracks in the sealing portion of the pouch wings of a battery cell through heating and bending the pouch wings while heating the sealing portion of the pouch wings of the battery cell. means of solving the problem

[0024] To solve the above-mentioned problem, a pouch wing folding device for a battery cell according to one aspect of the present invention may include a seating portion on which the battery cell is seated so that the pouch wing of the battery cell is exposed to the outside, a first contact surface and a second contact surface inclined at an acute angle from the first contact surface, a folding processing portion arranged to first fold the pouch wing while moving in a first direction while the first contact surface is in contact with the first surface of the pouch wing, and secondly fold the first surface of the pouch wing while the second contact surface moves in a second direction different from the first direction, a first heating blade positioned between the folding processing portion and the seating portion and movably arranged to contact the first surface of the pouch wing, and a second heating blade having a contact end arranged to engage with the second contact surface of the folding processing portion, movably arranged to contact the second surface of the pouch wing, and arranged to heat a portion of the pouch wing together with the first heating blade.

[0025] In addition, when the pouch wing is first pressed by the folding processing part, the size of the folding angle of the pouch wing may be larger than the size of the folding angle when the pouch wing is second pressed.

[0026] In addition, the above-mentioned bending part may be a heating block provided to supply heat to the pouch wing.

[0027] In addition, the above-mentioned folding part may be provided to be in surface contact with the pouch wing when the pouch wing is pressed.

[0028] In addition, the bending portion may have a first contact surface that contacts the first surface of the pouch wing at an initial position for first pressing, and a second contact surface that is inclined at an acute angle with respect to the first contact surface and contacts the first surface of the pouch wing during second pressing.

[0029] In addition, the above-mentioned bending processing part may be bent with a predetermined curvature and may have a curved part connecting the first contact surface and the second contact surface.

[0030] delete

[0031] In addition, the bending portion may be configured such that the second contact surface is inclined within a range of 55 to 85 degrees relative to the first contact surface.

[0032] Additionally, a pair of heating blades may include a first heating blade in contact with a first surface of the pouch wing and a second heating blade in contact with a second surface opposite to the first surface of the pouch wing.

[0033] In addition, the above-mentioned bending portion may be configured such that, upon secondary pressing, the second contact surface moves toward the second heating blade, and the pouch wing contacts the second heating blade and the second contact surface, respectively.

[0034] In addition, the first and second heating blades may each include a main body in contact with the pouch wing and a heat source that provides heat to the main body.

[0035] In addition, the second heating blade can have the contact end of the main body in contact with the pouch wing bent in a direction toward the bending process.

[0036] In addition, the second heating blade may be bent so that one side of the contact end is parallel to the second contact surface of the bending process.

[0037] In addition, after the second pressing of the bending processing part is completed, the second heating blade moves in a direction away from the pouch wing, and one surface of the contact end of the second heating blade may be arranged to press the pouch wing a third time.

[0038] In addition, after the second pressing of the bending processing part is completed, the second heating blade may be arranged to move in the opposite direction to the direction in which it moved to contact the pouch wing.

[0039] In addition, the second heating blade is moved away from the pouch wing, and by pressing the pouch wing in the opposite direction of the second direction, the pouch wing can be folded a third time.

[0040] In addition, according to another aspect of the present invention, a pouch-type battery cell is provided, comprising an electrode assembly and a pouch that accommodates the electrode assembly. The pouch includes a pouch wing sealed on the outer edge of the electrode assembly, and the pouch wing is folded multiple times to include a folded portion and an unfolded portion, and is arranged so that, when no external force is applied, the folded portion forms a certain angle in the range of 75 to 90 degrees with respect to the unfolded portion.

[0041] In addition, according to another aspect of the present invention, a method for folding a pouch wing of a battery cell is provided, comprising the step of folding the pouch wing at least twice in different directions using a pouch wing folding device of the battery cell. Effects of the invention

[0042] As described above, the pouch-type battery cell, the battery cell pouch wing folding device, and the battery cell pouch wing folding method related to at least one embodiment of the present invention have the following effects.

[0043] The present invention melts the sealing portion of a pouch wing using a pair of heating blades, thereby preventing and eliminating the occurrence of cracks in the sealing portion during the folding process of the pouch wing. Accordingly, the present invention can improve the insulation resistance performance of a battery cell by preventing defects in insulation resistance caused by cracks in the sealing portion.

[0044] The present invention is provided with an inverted trapezoidal block structure of the folding processing part and a structure in which the folding processing part and the upper heating blade interlock. When the pouch wing is folded, the pouch wing is pushed toward the upper heating blade at a predetermined angle, causing the pouch wing to be further folded inward and undergo plastic deformation, thereby preventing the pouch wing from spreading more than 90 degrees. Accordingly, the present invention prevents the spring back phenomenon of the pouch wing, thereby allowing the pouch wing to be continuously maintained in a 90-degree folded state.

[0045] In addition, compared to a conventional roller-type structure, the present invention has a block-type structure for the bending process, which can bend the pouch wing while in surface contact with the pouch wing, thereby increasing the contact area of ​​the bending process with the pouch wing, and thus allowing the pouch wing to be bent more stably compared to the conventional method.

[0046] The present invention provides a curved portion in the bending processing section, so that the pouch wing can be pushed up to be bent at a predetermined angle without minimizing friction on the pouch wing and without damaging the pouch wing, just as a conventional pressure roller pushes up the pouch wing.

[0047] Due to the structural features described above, the present invention can improve the insulation resistance performance by more than twofold compared to folding pouch wings with a conventional roller type. Brief explanation of the drawing

[0048] Figure 1 is an exploded perspective view of the general structure of a pouch-type battery. FIG. 2 is a flowchart illustrating a folding method for folding pouch wings of a battery cell according to the prior art. Figure 3 illustrates the state of the sealing portion after folding the pouch wing according to the prior art. FIG. 4 schematically illustrates a configuration diagram of a pouch wing folding device for a battery cell according to one embodiment of the present invention. FIG. 5 schematically illustrates a cross-sectional view of a bending processing part according to one embodiment of the present invention. FIGS. 6 to 10 are drawings for explaining the process of folding a pouch wing of a battery cell using a pouch wing folding device of a battery cell according to an embodiment of the present invention. FIG. 11 illustrates the state of the sealing portion after folding the pouch wing according to one embodiment of the present invention. FIG. 12 is a drawing showing a pouch wing of a pouch-type battery cell according to one embodiment of the present invention. Specific details for implementing the invention

[0049] Hereinafter, a pouch-type battery cell and a pouch wing folding device for a battery cell according to a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0050] FIG. 4 is a diagram showing the configuration of a pouch wing folding device for a battery cell according to one embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view of a folding processing part according to one embodiment of the present invention.

[0051] In addition, FIGS. 6 to 10 are drawings for explaining the process of folding a pouch wing of a battery cell using a pouch wing folding device of a battery cell according to an embodiment of the present invention.

[0052] In addition, FIG. 11 illustrates the state of the sealing portion after folding the pouch wing according to one embodiment of the present invention, and FIG. 12 is a drawing showing the pouch wing of a pouch-type battery cell according to one embodiment of the present invention.

[0054] As described in FIG. 1, the pouch-type battery cell (10) includes an electrode assembly (13) and a pouch (12) that accommodates the electrode assembly (13).

[0055] The above pouch (12) includes a pouch wing (12a) sealed on the outer edge of the electrode assembly (13). Additionally, referring to FIG. 12, the pouch wing (12a) is folded multiple times and includes a folded portion (12e) and an unfolded portion (12d), and when no external force is applied, the folded portion (12e) forms a constant angle (θ3) with respect to the unfolded portion (12d) in the range of 75 to 90 degrees.

[0056] The sealed pouch wing (12a) has three bending points along the direction toward the edge, has an overlapping portion (12e) in the shape of a "C" on the outer side, and the pouch wing (12a) has an unoverlapping portion (12d) in the area adjacent to the electrode assembly side.

[0057] In addition, the state in which no external force is applied means that the pouch wing (12a) is not wrapped with tape or the like.

[0058] That is, when the folding process of the pouch wing (12a) is completed through the pouch wing folding device (100) of the battery cell described herein, the pouch wing (12a) can maintain a constant angle (θ3) in the range of 75 to 90 degrees with respect to the unfolded part (12d), and preferably, the pouch wing (12a) can maintain a constant angle (θ3) in the range of 80 to 90 degrees with respect to the unfolded part (12d).

[0060] A pouch wing folding device (100) of a battery cell according to one embodiment of the present invention is a device for folding a pouch wing (12a) of a battery cell (10).

[0061] Referring to FIG. 4, the pouch wing folding device (100) of a battery cell includes a seating portion (110), a folding portion (120), and a pair of heating blades (131, 132).

[0062] The battery cell (10) is placed on the mounting portion (110) such that the pouch wing (12a) of the battery cell is exposed to the outside. Specifically, the battery cell (10) is placed on the mounting portion (110) such that the pouch wing (12a) is exposed laterally.

[0063] In addition, a pair of heating blades (131, 132) and a bending processing part (120) are each installed spaced apart from the seating part (110) in the lateral direction of the seating part (110).

[0064] A pair of heating blades (131, 132) are arranged facing each other at a predetermined distance. Additionally, each of the pair of heating blades (131, 132) is movably provided to contact the pouch wing (12a) and is provided to heat the pouch wing (12a) when in contact with the pouch wing (12a).

[0065] The pouch wing (12a) may have a first surface (12f) and a second surface (12g) opposite to the first surface (12f). At this time, a pair of heating blades (131, 132) may include a first heating blade (132) in contact with the first surface (12f) of the pouch wing (12a) and a second heating blade (131) in contact with the second surface (12g) opposite to the first surface (12f) of the pouch wing.

[0066] At this time, based on the arrangement relationship between the components shown in FIG. 4, the second heating blade (131) may be referred to as the upper heating blade and the first heating blade (132) may be referred to as the lower heating blade. Additionally, a pair of heating blades (131, 132) each come into contact with the non-overlapping portion (12d) of the pouch wing (12a).

[0067] The folding processing unit (120) is configured to fold the pouch wing (12a) by moving along a first direction (F1) while a pair of heating blades (131, 132) are in contact with the pouch wing (12a), thereby applying primary pressure to the pouch wing (12a), and by moving along a second direction (F2) different from the first direction (F1), thereby applying secondary pressure to the pouch wing (12a). The folding processing unit (120) may be configured to fold the pouch wing (12a) twice along different directions.

[0068] When the pouch wing is first pressed by the folding processing part (120), the size of the folding angle of the pouch wing may be larger than the size of the folding angle when the pouch wing is second pressed.

[0069] The bending device (100) includes a pair of heating blades (131, 132) and a control unit (180) for controlling the movement and operation (heating) of the bending processing unit (120).

[0070] Referring to FIG. 4, at an initial position prior to the bending process, the bending processing unit (120) is located at the lower part of the first surface (12f) of the pouch wing (12a). The bending processing unit (120) comes into contact with the first surface (12f) of the pouch wing (12a) at the initial position and bends the pouch wing (12a) in the first step while moving upward from the initial position. Additionally, the bending processing unit (120) is provided to supply heat to the pouch wing (12a).

[0071] The above-mentioned bending processing part (120) may be a heating block provided to supply heat to the pouch wing (12a). The above-mentioned bending processing part (120) may contain a heat source inside, and the heat source may be a self-heating heater rod (Cartridge Heater Pipe). Additionally, one or more heater rods may be included inside the bending processing part (120), and inside the heater rod may include a ceramic core that forms the shape of the heater rod and acts as a support rod, a heating coil that surrounds the ceramic core, and a wire that supplies electricity to the heating coil.

[0072] Referring to FIG. 5, the bending processing part (120) can be configured to make surface contact with the pouch wing (12a) when the pouch wing (12a) is pressed. That is, the bending processing part (120) has a block-shaped structure with a flat surface that contacts the pouch wing (12a) when pressed. For example, the bending processing part (120) may have an approximately inverted trapezoidal cross-section.

[0073] In this document, the folding processing part (120) has a different surface that contacts the pouch wing (12a) during the first and second pressing, respectively, and each contact surface may be referred to as a first contact surface (121) and a second contact surface (122). The folding processing part may have a first contact surface (121) that contacts the first surface (12f) of the pouch wing (12a) at the initial position for the first pressing, and a second contact surface (122) that is inclined at an acute angle with respect to the first contact surface (121) and contacts the first surface (12f) of the pouch wing (12a) during the second pressing.

[0074] The first contact surface (121) is a surface that contacts the pouch wing (12a) when the folded processing part (120) is placed in the initial position and when it moves upward from the initial position. The second contact surface (122) is a surface that contacts the pouch wing (12a) when the folded processing part (120) is pressed twice. The second contact surface (122) is folded and extended downward from the first contact surface (121). In particular, when the second contact surface is pressed twice, the second contact surface (122) contacts the overlapping part (12e) of the pouch wing (12a).

[0075] The second contact surface (122) is bent at an angle of inclination relative to the first contact surface (121). At this time, the bending portion (120) may be provided such that the angle of inclination (θ1) of the second contact surface (122) relative to the first contact surface (121) is within the range of 55 to 85 degrees.

[0076] In this way, due to the structure in which the second contact surface (122) of the bending processing part (120) is inclined with respect to the first contact surface (121), when the pouch wing (12a) is bent, the pouch wing (12a) is pushed at an angle toward the upper heating blade (131) at a predetermined angle, so that the pouch wing (12a) is further bent inward (in the direction toward the electrode assembly) and undergoes plastic deformation, thereby preventing the pouch wing (12a) from opening more than 90 degrees. That is, by preventing the spring back phenomenon of the pouch wing (12a), the pouch wing (12a) can be continuously maintained in a 90-degree bent state.

[0077] Additionally, the bending processing part (120) may be bent with a predetermined curvature and may have a curved part (123) connecting the first contact surface (121) and the second contact surface (122). In this structure, with reference to FIG. 4, the angle of inclination (θ1) of the second contact surface (122) with respect to the first contact surface (121) may mean the angle formed at the point where imaginary line segments extending from each contact surface intersect.

[0078] Compared to a conventional roller-type structure, the bending processing part (120) has a block-type structure, and can bend the pouch wing (12a) by making surface contact with the pouch wing (12a) during first and second pressing. In addition, the contact area with the pouch wing (12a) of the bending processing part (120) is widened when pressing, so the pouch wing (12a) can be bent stably.

[0079] Additionally, the bending portion (120) has a curved portion (123). The curved portion (123) can be formed by rounding the portion where the first contact surface (121) and the second contact surface (122) are connected.

[0080] The bending processing part (120) bends the pouch wing (12a) by moving upward from the initial position (first direction, F1) so that the pouch wing (12a) moves along the curved part (123) and contacts the second contact surface (122) while the first contact surface (121) is in contact with the first surface (12F) of the pouch wing (12a).

[0081] At this time, the bending processing part (120) can push up the pouch wing (12a) at a predetermined angle without damaging the pouch wing (12a) and with the bending part (123), just as a conventional pressure roller pushes up the pouch wing (12a).

[0082] When the above-mentioned bending portion (120) is moved along a first direction (F1) while the first contact surface (121) is in contact with the first surface (12f) of the pouch wing, the first contact surface (121), the curved portion (123), and the second contact surface (122) may sequentially come into contact with the first surface (12f) of the pouch wing (12a).

[0083] Referring to FIG. 4, a pair of heating blades (131, 132) are movably arranged to contact the first surface (12f, also called the ‘bottom surface’) and the first surface (12g, also called the ‘top surface’) of the pouch wing (12a) respectively in a position facing each other.

[0084] Meanwhile, in this embodiment, the portion where a pair of heating blades (131, 132) come into contact with the pouch wing (12a) may be referred to as a sealing portion. Referring to FIG. 11, heat can be applied through a pair of heating blades (131, 132) to form a sealing portion (12b).

[0085] A pair of heating blades (131, 132) are provided to be movable in a direction closer to the pouch wing (12a) and a direction further away from the pouch wing (12a). For example, the pair of heating blades (131, 132) have a structure that can move up and down. The pair of heating blades (131, 132) supply heat to the pouch wing (12a) and perform the function of holding the pouch wing (12a) during the folding process.

[0086] The present invention can prevent cracks from occurring in the sealing portion (12b) of the pouch wing (12a) during the folding process of the pouch wing (12a) by melting the sealing portion (see 12b in FIG. 11) through a pair of heating blades (131, 132).

[0087] Each heating blade (131, 132) includes a main body (131b, 132b) in contact with the pouch wing (12a) and a heat source (131a, 132a) that provides heat to the main body (131b, 132b). The main body (131b, 132b) may extend from the heat source (131a, 132a).

[0088] The second heating blade (131) located at the top includes an upper heat source (131a) and a main body (131b, 131c) extending from the upper heat source (131a), and the main body includes a connecting end (131b) connected to the upper heat source (131a) and a contact end (131c) extending from the connecting end (131b).

[0089] A first heating blade (132) located at the bottom includes a lower heat source (132a) and a body (132b) extending from the lower heat source (132a), and the body includes a contact end for contacting a pouch wing (12a).

[0090] Here, the contact end (132b) has a structure capable of pressing the sealing portion (12b) by contacting the pouch wing (12a). The main body of each heating blade (131, 132) may have a rod shape.

[0091] Meanwhile, the second heating blade (131) located at the top has a shape in which the contact end (131c) of the main body corresponds to the bending part (120).

[0092] The second heating blade (131) has a shape in which the contact end (131c) of the main body that contacts the pouch wing (12a) is bent in a direction toward the bending processing part (120). Specifically, the second heating blade (131) can be bent so that one side (131d) of the contact end (131c) is parallel to the second contact surface (122) of the bending processing part (120). The one side (131d) of the contact end (131c) is a surface that contacts one side (12h, the surface facing the electrode assembly) of the overlapping area (12e) of the pouch wing when a second press is applied through the bending processing part (120).

[0093] For example, if the bending portion (120) has a block structure with an inverted trapezoidal cross-section, the contact end (131c) has a structure that is bent at a predetermined angle with respect to the connecting end (131b) in correspondence with the shape of the bending portion (120). At this time, the angle of inclination (θ2) of the contact end (131c) with respect to the connecting end (131b) may be within the range of 145 degrees to 175 degrees.

[0094] The above-mentioned bending processing part (120) may be configured such that, upon secondary pressing, the second contact surface (122) moves toward the second heating blade (131), and the pouch wing (12a) contacts the second heating blade (131) and the second contact surface (122), respectively. That is, upon secondary pressing, the overlapping area (12e) of the pouch wing contacts the one side (131d) of the contact end (131c) of the second heating blade (131) and the second contact surface (122) of the bending processing part (120), respectively.

[0095] The present invention, through the structure of the contact end (131c) of the second heating blade (131) and the bending processing part (120) and the method of applying heat, when a second pressurization is applied, the overlapping area (122) of the pouch wing (12a) is bent to a range of 55 to 85 degrees relative to the non-overlapping area (12d), and the upper and lower surfaces of the pouch are simultaneously plastically deformed, thereby preventing the pouch wing (12a) from spreading more than 90 degrees after the bending processing is completed.

[0096] That is, by preventing the spring back phenomenon of the pouch wing (12a), the pouch wing (12a) can be maintained in a 90-degree bent state.

[0097] Hereinafter, with reference to FIGS. 6 to 10, a method for bending a pouch wing (12a) using a pouch wing bending device (100) of a battery cell according to one embodiment of the present invention will be described.

[0098] FIG. 6 is a drawing for explaining a process of folding twice to form a “C”-shaped overlapping portion (12e in FIG. 12) on the edge of a pouch wing.

[0099] As illustrated in FIG. 6(a), a battery cell (10) is prepared. At this time, the pouch flap of the battery cell (10) is sealed on its upper and lower surfaces. In FIG. 6(a), the shape of the pouch flap (12a) of the battery cell is referred to as the initial shape.

[0100] Next, as illustrated in FIG. 6(b), the guide rod (50) holds the pouch wing (12a) while pressing the upper and lower surfaces of the pouch wing (12a). Subsequently, the bending block (60) moves from the lower part of the pouch wing (12a) to the upper part (vertical movement) and first bends the pouch wing (12a) 90 degrees relative to its initial shape.

[0101] Next, as shown in FIG. 6(c), the bending block (60) is moved forward (horizontally) toward the battery cell, and the end portion of the overlapping area of ​​the pouch wing (12a) is folded a second time so that it is 180 degrees relative to the initial shape.

[0102] FIGS. 7 to 10 is a process of additionally folding the pouch wing (12a) after the process described in FIG. 6 is completed. FIGS. 7 to 10 are drawings for explaining the process of folding the pouch wing of a battery cell using a pouch wing folding device of a battery cell according to an embodiment of the present invention.

[0103] That is, in the pouch wing (12a), it represents a process of folding the overlapping area for the non-overlapping area.

[0104] Referring to FIGS. 7 and 8, the second heating blade (131) is positioned to contact the upper surface of the pouch wing (12a) and the first heating blade (132) is positioned to contact the lower surface of the pouch wing (12a), thereby holding the pouch wing (12a) up and down. At this time, the second heating blade (131) and the first heating blade (132) supply heat to the pouch wing (12a). The sealing portion of the pouch wing (12a) is melted by the second heating blade (131) and the first heating blade (132) (see 12b in FIG. 11).

[0105] Next, referring to FIG. 8, the bending portion (120) moves from the initial position upward (first direction, F) while in contact with the lower surface of the pouch wing (12a).

[0106] As illustrated in FIG. 9, the bending portion (120) moves in a second direction (F2) toward the upper heating blade (131) and presses the overlapping area of ​​the pouch wing (12a). Meanwhile, the first direction (e.g., vertical direction) and the second direction (e.g., horizontal direction) may be orthogonal directions.

[0107] Referring to FIG. 9, when the second pressurization is applied after the first pressurization is completed, the pouch wing (12a) undergoes plastic deformation as the overlapping area is bent at an acute angle relative to the non-overlapping area. Accordingly, the spring back phenomenon of the pouch wing (12a) after bending can be prevented.

[0108] For example, the temperature applied to the overlapping portion through the bending processing unit (120) is 160 to 200 ℃, the pressure is 0.2 to 0.7 MPa, and the heat compression through the bending processing unit (120) can be performed for 1 to 10 seconds.

[0109] When the folding process of the pouch wing (12a) according to FIG. 9 is completed, the second heating blade (131), the first heating blade (132), and the folding processing part (120) return to their original positions as shown in FIG. 10.

[0110] Referring to FIG. 10, after the second pressing of the bending processing part (120) is completed, the second heating blade (131) is moved away from the pouch wing (12a), and one side (131d) of the contact end (131c) of the second heating blade (131) is arranged to press the pouch wing (12a) a third time.

[0111] Referring to FIG. 10, after the second pressing of the bending processing part (120) is completed, the second heating blade (131) moves from its initial position in the opposite direction to the direction in which it moved to contact the pouch wing (12a). As the second heating blade (131) moves away from the pouch wing (12a) and presses the pouch wing (12a) in the opposite direction of the second direction (F2), the pouch wing (12a) can be bent a third time.

[0112] Referring to FIG. 10 and FIG. 12, through a third folding process, the pouch wing (12a) forms a certain angle (θ3) in the range of 75 to 90 degrees with respect to the unfolded part (12d) without any external force being applied.

[0114] Below, we will explain the bending process efficiency with reference to Tables 1 and 2.

[0115] division Insulation resistance section Insulation resistance value before bending process Insulation resistance value after bending process Growth rate Average growth rate Case 1 Heating Blade - Heat Source Supply X 1MΩ~49MΩ 3MΩ 5MΩ 67％ 317％ 5MΩ 15MΩ 200％ 13MΩ 56MΩ 331％ 27MΩ 208MΩ 670％ 50MΩ~99MΩ 55MΩ 247MΩ 349％ 534％ 71MΩ 470MΩ 562％ 82MΩ 548MΩ 567％ 88MΩ 667MΩ 658％ 100MΩ or more 140MΩ 684MΩ 389％ 186％ 210MΩ 705MΩ 236％ 429MΩ 720MΩ 68％ 505MΩ 770MΩ 52％ Case 2 Heating Blade - Heat Source Supply O 1MΩ~49MΩ 4MΩ 10MΩ 150％ 373％ 8MΩ 23MΩ 188％ 18MΩ 126MΩ 600％ 42MΩ 275MΩ 555％ 50MΩ~99MΩ 51MΩ 345MΩ 576％ 652％ 62MΩ 512MΩ 726％ 78MΩ 589MΩ 655％ 92MΩ 691MΩ 651％ 100MΩ or more 160MΩ 680MΩ 325％ 221％ 230MΩ 810MΩ 252％ 370MΩ 1000MΩ 170％ 420MΩ 1000MΩ 138％

[0116] Insulation resistance value range Average growth rate of Case 1 Average growth rate of Case 2 Improvement rate of Case 2 1MΩ~49MΩ 317% 373% 18% 50MΩ~99MΩ 534% 652% 22% 100MΩ or more 186% 221% 19%

[0118] Table 1 shows the improvement rate of insulation resistance values ​​when a heat source is not supplied by a heating blade (Case 1) and when a heat source is supplied by a heating blade (Case 2).

[0119] In Table 1 above, Case 1 is the insulation resistance improvement rate when the pouch wing (12a) is bent using the bending processing part (120) while the heating blade (131, 132) is not supplied with a heat source.

[0120] And, Case 2 shows the insulation resistance improvement rate when the pouch wing (12a) is bent using the block-type bending processing part (120) while a heat source is supplied to the heating blades (131, 132).

[0121] In Tables 1 and 2 above, the insulation resistance range is a range set based on the block type and is broadly divided into a range of 1 MΩ to 49 MΩ, a range of 50 MΩ to 99 MΩ, and 100 MΩ or more.

[0122] In Case 1, it can be seen that the bending processing part (120) having a block-type structure according to one embodiment of the present invention improves the insulation resistance value, which has a range of 1 MΩ to 49 MΩ before bending processing, by an average of 317% after bending processing, improves the insulation resistance value, which has a range of 50 MΩ to 99 MΩ before bending processing, by an average of 534% after bending processing, and improves the insulation resistance value, which has a range of 100 MΩ before bending processing, by an average of 186% after bending processing.

[0123] In Case 2, it can be seen that the bending processing part (120) having a block-type structure according to one embodiment of the present invention improves the insulation resistance value, which has a range of 1 MΩ to 49 MΩ before bending processing, by an average of 373% after bending processing, improves the insulation resistance value, which has a range of 50 MΩ to 99 MΩ before bending processing, by an average of 652% after bending processing, and improves the insulation resistance value, which has a range of 100 MΩ before bending processing, by an average of 221% after bending processing.

[0124] Referring to Case 1 and Case 2 above, it can be seen that in the present invention, due to the block-type bending processing part (120), the insulation resistance is improved by at least 2 times when comparing the before and after bending processing.

[0125] Table 2 summarizes the average increase / decrease rate of insulation resistance for Cases 1 and 2 of Table 1, and the improvement rate of insulation resistance due to heat supply from the heating blade. Here, Cases 1 and 2 were tested under the same conditions.

[0126] Referring to Table 2, when examining the improvement rate of Case 2 compared to Case 1, it can be seen that when heat is supplied with a heating blade (Case 2), the insulation resistance is improved with an improvement rate of 18% in the range of 1 MΩ to 49 MΩ, an improvement rate of 22% in the range of 50 MΩ to 99 MΩ, and an improvement rate of 19% at 100 MΩ or higher, compared to when heat is not supplied with a heating blade (Case 1).

[0127] A person skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing its technical concept or essential features.

[0128] Therefore, the embodiments described above should be understood as exemplary in all respects and not limiting.

[0129] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0130] 100: Battery cell pouch flap folding device 110: Seating part 120: Bending Processing Department 121: First contact surface 122: Second contact surface 123: Curved section 131: 2nd heating blade (upper heating blade) 132: 1st heating blade (lower heating blade)

Claims

Claim 1 A battery cell pouch wing bending device comprising: a seating portion on which the battery cell is seated so that the pouch wing of the battery cell is exposed to the outside; a bending processing portion having a first contact surface and a second contact surface inclined at an acute angle from the first contact surface, wherein the first contact surface moves in a first direction while in contact with a first surface of the pouch wing to bend the pouch wing first, and the second contact surface moves in a second direction different from the first direction to bend the first surface of the pouch wing second; a first heating blade positioned between the bending processing portion and the seating portion and movably provided to contact the first surface of the pouch wing; and a second heating blade having a contact end provided to engage with the second contact surface of the bending processing portion, movably provided to contact the second surface of the pouch wing, and provided to heat a portion of the pouch wing together with the first heating blade. Claim 2 A battery cell pouch wing folding device according to claim 1, characterized in that, when the pouch wing is first pressed by the folding processing part, the size of the folding angle of the pouch wing is larger than the size of the folding angle when the pouch wing is secondarily pressed. Claim 3 A battery cell pouch wing folding device according to claim 1, characterized in that the folding processing part is a heating block provided to supply heat to the pouch wing. Claim 4 A battery cell pouch wing bending device according to claim 3, characterized in that the bending processing part is provided to be in surface contact with the pouch wing when the pouch wing is pressed. Claim 5 delete Claim 6 A pouch wing folding device for a battery cell according to claim 1, wherein the folding processing part is bent at a predetermined curvature and has a curved portion connecting the first contact surface and the second contact surface. Claim 7 A battery cell pouch wing folding device according to claim 6, wherein the folding processing part is characterized in that, when the first contact surface is in contact with the first surface of the pouch wing and is moved along a first direction, the first contact surface, the curved part, and the second contact surface sequentially come into contact with the first surface of the pouch wing. Claim 8 A pouch wing folding device for a battery cell according to claim 7, characterized in that the folding processing part is provided such that the second contact surface is inclined within a range of 55 to 85 degrees with respect to the first contact surface. Claim 9 A pouch wing folding device for a battery cell according to claim 1, characterized in that, when a second pressurization is applied, the second contact surface moves toward the second heating blade, and the pouch wing is arranged to contact the second heating blade and the second contact surface, respectively. Claim 10 A battery cell pouch wing folding device according to claim 9, wherein the first and second heating blades each include a main body in contact with the pouch wing and a heat source providing heat to the main body, and the second heating blade is characterized in that the contact end of the main body in contact with the pouch wing is bent in a direction toward the folding processing part. Claim 11 A pouch wing folding device for a battery cell according to claim 10, wherein the second heating blade is bent such that one surface of the contact end is parallel to the second contact surface of the folding processing part. Claim 12 A battery cell pouch wing bending device according to claim 11, characterized in that after the second pressing of the bending processing part is completed, the second heating blade moves in a direction away from the pouch wing, and one surface of the contact end of the second heating blade is provided to press the pouch wing a third time. Claim 13 A battery cell pouch wing bending device according to claim 12, characterized in that after the secondary pressing of the bending processing part is completed, the second heating blade moves in the opposite direction to the direction in which it moved to contact the pouch wing. Claim 14 A battery cell pouch wing folding device according to claim 12, characterized in that the second heating blade is moved away from the pouch wing, and the pouch wing is pressed in the opposite direction of the second direction, thereby causing the pouch wing to be folded a third time. Claim 15 delete

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