Pouch-type battery cell and pouch wing folding device for pouch-type battery cell

Abstract

The present invention relates to a pouch-type battery cell, a battery cell pouch wing folding device, and a battery cell pouch wing folding method, and more specifically, to a pouch-type battery cell, a battery cell pouch wing folding device, and a battery cell pouch wing folding method that can improve the insulation resistance performance of a battery cell by folding the pouch wings while heating the sealing portion of the pouch wings of the battery cell to prevent and remove cracks in the sealing portion.

Description

Technical Field

[0001] The present invention relates to a pouch-type battery cell, a pouch wing bending device for a battery cell, and a pouch wing bending method for a battery cell. Specifically, by bending the pouch wing while heating the sealing portion of the pouch wing of the battery cell to prevent and remove cracks in the sealing portion, the present invention relates to a pouch-type battery cell, a pouch wing bending device for a battery cell, and a pouch wing bending method for a battery cell that can improve the insulation resistance performance of the battery cell.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0109811 filed on August 20, 2021, and all contents disclosed in the document of the corresponding Korean patent application are included as part of this specification.

Background Art

[0003] A secondary battery generally refers to a lithium secondary battery, which has a polymer electrolyte and refers to a battery that generates current by the movement of lithium ions. A pouch for a secondary battery is used as an exterior material for packaging such a secondary battery.

[0004] In FIG. 1, a general structure of a pouch-type secondary battery is schematically illustrated in an exploded perspective view.

[0005] Referring to FIG. 1, the pouch-type secondary battery 10 includes an electrode assembly 13, electrode tabs 14 and 15 extending from the electrode assembly 13, electrode leads 16 and 17 welded to the electrode tabs 14 and 15, and a secondary battery pouch 12 that houses the electrode assembly 13.

[0006] 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 therebetween, and is formed in a stack type or a stack / folding type structure. The electrode tabs 14 and 15 extend from each electrode plate of the electrode assembly 13.

[0007] The electrode leads 16 and 17 are electrically connected to a plurality of electrode tabs 14 and 15 extending from each electrode plate, for example, by welding, and a part of them is exposed outside the pouch 12 for the secondary battery. Further, an insulating film 18 is attached to a part of the upper and lower surfaces of the electrode leads 16 and 17 to enhance the sealing degree with the pouch 12 for the secondary battery and to ensure an electrically insulating state.

[0008] The pouch 12 for the secondary battery is made of an aluminum laminate sheet, provides a space capable of accommodating the electrode assembly 13, and has an overall pouch shape.

[0009] The pouch for the secondary battery protects the battery cell composed of the electrode assembly and the electrolytic solution flowing into the interior in a subsequent process, and is configured in a form in which an aluminum thin film is interposed to improve the complementarity to the electrochemical properties of the battery cell and the heat dissipation property and the like.

[0010] In order to protect the battery cell from external impacts, the aluminum thin film has a functional polymer film such as polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN), nylon resin, or liquid crystal polymer (LCP) forming an outer layer.

[0011] The pouch has the upper pouch and the lower pouch joined by heat fusion or the like at the outer peripheral surface portion. An adhesive layer made of a polyolefin such as polyethylene (PE), casted polypropylene (cPP), or polypropylene (PP) or a copolymer thereof is formed between the lower surface of the upper pouch and the upper surface of the lower pouch for mutual adhesion.

[0012] Such a pouch-type battery goes through the steps of housing the electrode assembly in a laminate sheet, injecting an electrolytic solution, and sealing it by heat fusion or the like. In order to vertically fold the outer peripheral surface of the battery cell or the heat fusion part (sealing part) and make it adhere to the side wall of the housing part, after being housed in a folding device, the sealing part is pressurized and folded.

[0013] However, when the sealing part is vertically folded by a folding device, there is a problem that as time passes, the folded part is restored, resulting in defects in the dimensional design of the battery cell and the need to repeat the operation again.

[0014] The present invention relates to a battery cell folding device including a heating member disclosed in Korean Patent Publication No. 10-2015-0035123. Briefly explaining the method of folding the outer peripheral surface of a battery cell using a battery cell folding device according to the prior art, it is as follows.

[0015] FIG. 2 is a flowchart for explaining a folding method for folding a pouch wing of a battery cell according to the prior art, and FIG. 3 illustrates the state of the sealing part after folding the pouch wing according to the prior art.

[0016] As shown in FIG. 2, the battery cell is positioned on the battery cell folding device to fold the outer peripheral surface of the battery cell. In the heat fusion process of the battery cell 10, a pouch wing 12a is formed in the direction of the outer peripheral surface of the housing part, and this process is a process of folding the pouch wing 12a.

[0017] The battery cell 10 is mounted on a base plate 20 formed on the battery cell folding device, and the folding part of the pouch wing 12a is fixed by folding guides 21 and 22. The pressing rollers 31 and 32 move downward to fold the pouch wing 12a vertically downward.

[0018] At this time, the pouch wing 12a of the battery cell 10 is folded by heating members 41 and 42 mounted at adjacent parts of the pressing rollers 31 and 32, and is heated to adhere to the side wall of the battery cell.

[0019] The battery cell bending device including a heating member disclosed in Korean Patent Publication No. 10-2015-0035123 solves the problem that defects may occur in the dimensional design of the battery cell due to the restoration of the bending part over time by vertically bending the outer peripheral surfaces of the battery cells using the heating member and closely attaching them to the side walls of the storage part.

[0020] In the above method, since the side walls of the battery cells are not heated, sufficient heat is not supplied to the sealing area of the battery cells, and there are parts where the sealing part is not melted. For this reason, there is a risk that fine cracks may occur in bundles in the sealing part of the pouch wing, resulting in insulation failure.

[0021] Insulation resistance indicates the degree of insulation between the aluminum pouch and the cell inside the cell pouch. As shown in FIG. 3, insulation failure is caused by the energization between the aluminum pouch and the cell due to a bundle of fine cracks 12c in the sealing part 12b of the pouch wing. Here, the sealing part 12b refers to the area where the pouch wing adheres with a weak adhesive force before sealing.

[0022] If a large number of battery cells with poor insulation resistance are discharged, equipment immobility is expected due to the detection of the full cup sensor, and there is concern about the accompanying production loss. Here, the full cup sensor is determined to be defective and discharged during the production of the battery cell when it cannot meet the specifications presented by the equipment. However, when the discharge port becomes full due to the defective cells being discharged, an alarm and equipment immobility occur.

[0023] On the other hand, when the sealing part of the pouch wing in the battery cell is fixed with tape and adjacent to the electrode assembly side, an overall width difference will inevitably occur between the tape-attached part and the tape-unattached part, resulting in process loss. Summary of the Invention Problems to be Solved by the Invention

[0024] The present invention aims to provide a pouch-type battery cell capable of improving the insulation resistance performance of a battery cell, a pouch wing bending device for a battery cell, and a pouch wing bending method for a battery cell, by bending the pouch wing while heating the sealing portion of the pouch wing of the battery cell to prevent and remove cracks in the sealing portion.

Means for Solving the Problems

[0025] To solve the above problems, according to one aspect of the present invention, there is provided a mounting portion on which the battery cell is mounted such that the pouch wing of the battery cell is exposed to the outside, a pair of heating blades arranged to face each other at a predetermined interval and movable so as to contact the pouch wing, and provided to heat the pouch wing, and a bending portion provided to bend the pouch wing by moving in a first direction while the pair of heating blades are in contact with the pouch wing to perform primary pressing on the pouch wing, and moving in a second direction different from the first direction to perform secondary pressing on the pouch wing.

[0026] Also, the magnitude of the bending angle of the pouch wing during primary pressing by the bending portion may be larger than the magnitude of the bending angle during secondary pressing.

[0027] Also, the bending portion may be a heating block provided to supply heat to the pouch wing.

[0028] Also, the bending portion may be provided to be in surface contact with the pouch wing when pressing the pouch wing.

[0029] Also, the bending portion may have a first contact surface that contacts the first surface of the pouch wing at an initial position for primary 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 secondary pressing.

[0030] Further, the bent portion may have a curved portion that curves with a predetermined curvature to connect the first contact surface and the second contact surface.

[0031] Further, when the bent portion moves along the first direction with the first contact surface in contact with the first surface of the pouch wing, the first contact surface, the curved portion, and the second contact surface may be provided so as to sequentially contact the first surface of the pouch wing.

[0032] Further, the bent portion may be provided such that the second contact surface is inclined within a range of 55 degrees to 85 degrees with respect to the first contact surface.

[0033] Further, the pair of heating blades may include a first heating blade that contacts the first surface of the pouch wing and a second heating blade that contacts the second surface in the opposite direction to the first surface of the pouch wing.

[0034] Further, during the secondary pressing of the bent portion, the second contact surface may be moved toward the second heating blade, and the pouch wing may be provided so as to contact the second heating blade and the second contact surface, respectively.

[0035] Further, the first and second heating blades may each include a main body that contacts the pouch wing and a heat supply source that provides heat to the main body.

[0036] Further, the contact end portion of the main body of the second heating blade that contacts the pouch wing may be bent in a direction toward the bent portion.

[0037] Further, the second heating blade may be bent such that one surface of the contact end portion is parallel to the second contact surface of the bent portion.

[0038] Further, after the secondary pressing of the bent portion is completed, the second heating blade may be moved in a direction away from the pouch wing, and one surface of the contact end portion of the second heating blade may be provided to perform a tertiary pressing on the pouch wing.

[0039] Also, after the secondary pressing of the bending portion is completed, the second heating blade may be provided to move in the direction opposite to the direction in which it moved to contact the pouch wing.

[0040] Also, the second heating blade is moved in a direction away from the pouch wing, and by pressing the pouch wing in the direction opposite to the second direction, the pouch wing can be tertiary bent.

[0041] Also, according to still another aspect of the present invention, a pouch-type battery cell including an electrode assembly and a pouch for housing the electrode assembly is provided. The pouch includes a pouch wing sealed by the outer contour of the electrode assembly, and the pouch wing includes a portion that is bent and overlapped multiple times and a non-overlapped portion. In a state where no external force is applied, the overlapped portion is provided to form a certain angle in the range of 75 degrees to 90 degrees with respect to the non-overlapped portion.

[0042] Also, according to still another aspect of the present invention, a method for bending a pouch wing of a battery cell is provided, which includes the step of bending the pouch wing at least twice in different directions using the pouch wing bending device of the battery cell.

Advantages of the Invention

[0043] As confirmed above, the pouch-type battery cell, the pouch wing bending device of the battery cell, and the method for bending the pouch wing of the battery cell according to at least one embodiment of the present invention have the following effects.

[0044] The present invention can melt the sealing portion of the pouch wing through a pair of heating blades, and prevent and remove the generation of cracks at the sealing portion during the bending process of the pouch wing. Accordingly, the present invention can improve the insulation resistance performance of the battery cell by preventing poor insulation resistance due to cracks at the sealing portion.

[0045] The present invention is provided with an inverted trapezoidal block structure of the bending portion and a structure in which the bending portion and the upper heating blade are engaged with each other. When the pouch wing is bent, the pouch wing is pushed out so as to be inclined at a predetermined angle toward the upper heating blade, and the pouch wing is plastically deformed while being further bent inward, so that the pouch wing can be prevented from spreading more than 90 degrees. Along with this, the present invention can prevent the spring back phenomenon of the pouch wing and can continuously maintain the state in which the pouch wing is bent at 90 degrees.

[0046] And, compared with the conventional roll type structure, in the present invention, the bending portion has a block type structure, and since the pouch wing can be bent while being in surface contact with the pouch wing, the contact area of the bending portion with respect to the pouch wing becomes wider, and the pouch wing can be bent more stably compared with the conventional case.

[0047] In the present invention, a curved portion is provided in the bending portion, and when the conventional pressure roller pushes up the pouch wing, the friction against the pouch wing is minimized, and the pouch wing can be pushed up so that the pouch wing is bent at a predetermined angle without damaging the pouch wing.

[0048] Due to the structural features as described above, the present invention can improve the insulation resistance performance by more than twice compared with bending the pouch wing with the conventional roller type.

Brief Description of the Drawings

[0049]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0050] Hereinafter, with reference to the accompanying drawings, 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.

[0051] FIG. 4 is a configuration diagram of a pouch wing folding device for a battery cell according to an embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view of a bending process section according to an embodiment of the present invention.

[0052] In addition, FIGS. 6 to 10 are drawings for explaining the process of bending the pouch wings of a battery cell using the pouch wing bending device according to an embodiment of the present invention.

[0053] In addition, FIG. 11 illustrates the state of the sealing portion after bending the pouch wings according to an embodiment of the present invention, and FIG. 12 is a drawing showing the pouch wings of a pouch-type battery cell according to an embodiment of the present invention.

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

[0055] The pouch 12 includes pouch wings 12a sealed with the outer contour of the electrode assembly 13. Referring to FIG. 12, the pouch wings 12a include an overlapping portion 12e and a non-overlapping portion 12d that are bent multiple times and overlapped. In a state where no external force is applied, the overlapping portion 12e forms a certain angle θ3 in the range of 75 degrees to 90 degrees with respect to the non-overlapping portion 12d.

[0056] The sealed pouch wings 12a will have three bending points along the direction towards the edge, and have an overlapping portion 12e in the shape of " JPEG0007694871000001.jpg3546" on the outer contour side, and the pouch wings 12a have a non-overlapping portion 12d in the region adjacent to the electrode assembly side.

[0057] In addition, the state where no external force is applied means that the pouch wings 12a are not wrapped through a tape or the like.

[0058] That is, when the bending process of the pouch wings 12a is completed through the pouch wing bending device 100 of the battery cell described in the present application, the overlapping portion 12e of the pouch wings 12a can maintain a certain angle θ3 in the range of 75 degrees to 90 degrees with respect to the non-overlapping portion 12d. Preferably, the overlapping portion 12e of the pouch wings 12a can maintain a certain angle θ3 in the range of 80 degrees to 90 degrees with respect to the non-overlapping portion 12d.

[0059] The pouch wing folding device 100 for a battery cell according to an embodiment of the present invention is a device for folding the pouch wing 12a of the battery cell 10.

[0060] Referring to FIG. 4, the pouch wing folding device 100 for a battery cell includes a mounting part 110, a folding part 120, and a pair of heating blades 131 and 132.

[0061] The battery cell 10 is mounted on the mounting part 110 such that the pouch wing 12a of the battery cell is exposed to the outside. Specifically, the battery cell 10 is mounted on the mounting part 110 such that the pouch wing 12a is exposed laterally.

[0062] Further, the pair of heating blades 131 and 132 and the folding part 120 are separately installed at a distance from the mounting part 110 in the lateral direction of the mounting part 110.

[0063] The pair of heating blades 131 and 132 are arranged to face each other at a predetermined interval. Further, the pair of heating blades 131 and 132 are each movably provided so as to contact the pouch wing 12a, and are provided to heat the pouch wing 12a when contacting the pouch wing 12a.

[0064] The pouch wing 12a can have a first surface 12f and a second surface 12g in a direction opposite to the first surface 12f. At this time, the pair of heating blades 131 and 132 can include a first heating blade 132 that contacts the first surface 12f of the pouch wing 12a and a second heating blade 131 that contacts the second surface 12g in a direction opposite to the first surface 12f of the pouch wing.

[0065] At this time, based on the arrangement relationship between the components illustrated in FIG. 4, in this document, 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. Also, the pair of heating blades 131, 132 will respectively contact the non-overlapping portion 12d of the pouch wing 12a.

[0066] The bending processing unit 120 is provided to bend the pouch wing 12a by moving along the first direction F1 to perform a primary pressing on the pouch wing 12a and moving along a second direction F2 different from the first direction F1 to perform a secondary pressing on the pouch wing 12a in a state where the pair of heating blades 131, 132 are in contact with the pouch wing 12a. The bending processing unit 120 may be provided to bend the pouch wing 12a twice along different directions from each other.

[0067] The magnitude of the bending angle of the pouch wing during the primary pressing of the pouch wing by the bending processing unit 120 may be larger than the magnitude of the bending angle during the secondary pressing.

[0068] The bending device 100 includes a control unit 180 for controlling the movement and operation (heating) of the pair of heating blades 131, 132 and the bending processing unit 120.

[0069] Referring to FIG. 4, at the initial position before the bending process is performed, the bending processing unit 120 is located below the first surface 12f of the pouch wing 12a. The bending processing unit 120 contacts the first surface 12f of the pouch wing 12a at the initial position and performs a primary bending on the pouch wing 12a while moving upward from the initial position. Also, the bending processing unit 120 is provided to supply heat to the pouch wing 12a.

[0070] The bending processing part 120 can be a heating block provided to supply heat to the pouch wing 12a. The bending processing part 120 includes a heat source inside, and the heat source can be a heater rod (Cartridge Heater Pipe) capable of generating heat by itself. Also, one or more heater rods are included inside the bending processing part 120, and the inside of the heater rod can include a ceramic core that forms the shape of the heater rod and serves as a support rod, a heating coil that wraps around the ceramic core, and an electric wire that supplies electricity to the heating coil.

[0071] Referring to FIG. 5, the bending processing part 120 can be provided to be in surface contact with the pouch wing 12a when pressing the pouch wing 12a. That is, the bending processing part 120 has a block-shaped structure with a flat surface that contacts the pouch wing 12a when pressing. As an example, the bending processing part 120 can have a substantially trapezoidal cross-section.

[0072] In this document, the bending processing part 120 has different contact surfaces with the pouch wing 12a during the first pressurization and the second pressurization, and the respective contact surfaces can be referred to as the first contact surface 121 and the second contact surface 122. The bending processing part has a first contact surface 121 that contacts the first surface 12f of the pouch wing 12a at the initial position for the first pressurization and is inclined at an acute angle with respect to the first contact surface 121, and can have a second contact surface 122 that contacts the first surface 12f of the pouch wing 12a during the second pressurization.

[0073] The first contact surface 121 is the surface that contacts the pouch wing 12a when the bending processing part 120 is placed at the initial position and when it moves upward from the initial position. The second contact surface 122 is the surface that the bending processing part 120 contacts the pouch wing 12a during the second pressurization. The second contact surface 122 is bent and extended below the first contact surface 121. In particular, during the second pressurization, the second contact surface 122 contacts the overlapping part 12e of the pouch wing 12a.

[0074] The second contact surface 122 is bent so as to be inclined at a predetermined angle with respect to the first contact surface 121. At this time, the bending portion 120 can be provided within a range where the inclination angle θ1 of the second contact surface 122 with respect to the first contact surface 121 is between 55 degrees and 85 degrees.

[0075] In this way, due to the structure in which the second contact surface 122 of the bending portion 120 is inclined with respect to the first contact surface 121, when the pouch wing 12a is bent, the pouch wing 12a is pushed out so as to be inclined at a predetermined angle toward the upper heating blade 131, and the pouch wing 12a is bent and deformed by baking while being further bent inward (in the direction toward the electrode assembly), thereby preventing the pouch wing 12a from spreading more than 90 degrees. That is, by preventing the spring back phenomenon of the pouch wing 12a, the pouch wing 12a can continuously maintain a 90-degree bent state.

[0076] Further, the bending portion 120 can have a curved portion 123 that is curved with a predetermined curvature to connect the first contact surface 121 and the second contact surface 122. With such a structure, referring to FIG. 4, the inclination angle θ1 of the second contact surface 122 with respect to the first contact surface 121 can mean the angle formed at the point where the virtual line segments extending from the respective contact surfaces intersect.

[0077] Compared with the conventional roll type structure, the bending portion 120 has a block type structure, and can bend the pouch wing 12a while making surface contact with the pouch wing 12a during primary and secondary pressurization. Further, during pressurization, the bending portion 120 has a larger contact area with respect to the pouch wing 12a and can stably bend the pouch wing 12a.

[0078] Further, 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.

[0079] The bending process section 120 bends the pouch wing 12a while moving upward (in the first direction, F1) from the initial position so that the first contact surface 121 contacts the first surface 12F of the pouch wing 12a and the pouch wing 12a rides on the curved portion 123 and contacts the second contact surface 122.

[0080] At this time, due to the curved portion 123, when the conventional pressure roller pushes up the pouch wing 12a, the bending process section 120 can minimize the friction against the pouch wing 12a and push up the pouch wing 12a so that the pouch wing 12a is bent at a predetermined angle without damage to the pouch wing 12a.

[0081] When the bending process section 120 moves along the first direction F1 with the first contact surface 121 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 can sequentially contact the first surface 12f of the pouch wing 12a.

[0082] Referring to FIG. 4, a pair of heating blades 131, 132 are movably provided so as to contact the first surface (12f, also referred to as the "lower surface") and the first surface (12g, also referred to as the "upper surface") of the pouch wing 12a at positions facing each other.

[0083] On the other hand, in this embodiment, the portion where the pair of heating blades 131, 132 contact the pouch wing 12a can be referred to as a sealing portion. Referring to FIG. 11, heat can be applied through the pair of heating blades 131, 132 to form the sealing portion 12b.

[0084] The pair of heating blades 131, 132 are movably provided in a direction approaching the pouch wing 12a and a direction away from the pouch wing 12a. As an example, the pair of heating blades 131, 132 have a structure that can move up and down. The pair of heating blades 131, 132 perform a function of supporting the pouch wing 12a during the bending process while supplying heat to the pouch wing 12a.

[0085] The present invention can prevent cracks from occurring in the sealing portion (see 12b in FIG. 11) of the pouch wing 12a by melting the sealing portion of the pouch wing 12a through a pair of heating blades 131 and 132 during the bending process of the pouch wing 12a.

[0086] Each of the heating blades 131 and 132 includes a main body 131b, 132b that contacts the pouch wing 12a and a heat supply source 131a, 132a that provides heat to the main bodies 131b, 132b. The main bodies 131b, 132b can extend from the heat supply sources 131a, 132a.

[0087] The second heating blade 131 located at the upper part includes an upper heat supply source 131a and a main body 131b, 131c extending from the upper heat supply source 131a. The main body includes a connecting end portion 131b connected to the upper heat supply source 131a and a contact end portion 131c extending from the connecting end portion 131b.

[0088] The first heating blade 132 located at the lower part includes a lower heat supply source 132a and a main body 132b extending from the lower heat supply source 132a. The main body includes a contact end portion for contacting the pouch wing 12a.

[0089] Here, the contact end portion 132b has a structure capable of contacting the pouch wing 12a and pressing the sealing portion 12b. The main bodies of the heating blades 131 and 132 can each have a rod shape.

[0090] On the other hand, the second heating blade 131 located at the upper part has a shape in which the contact end portion 131c of the main body corresponds to the bending processing portion 120.

[0091] The second heating blade 131 has a form in which the contact end 131c of the main body that contacts the pouch wing 12a is bent in a direction toward the bending portion 120. Specifically, the second heating blade 131 can be bent such that one surface 131d of the contact end 131c is parallel to the second contact surface 122 of the bending portion 120. One surface 131d of the contact end 131c is a surface that contacts one surface (12h, the surface facing the electrode assembly) of the overlapping region 12e of the pouch wing during secondary pressing through the bending portion 120.

[0092] As an example, when the bending portion 120 has a block structure with an inverted trapezoidal cross section, the contact end 131c has a structure bent at a predetermined angle with respect to the connecting end 131b so as to correspond to the shape of the bending portion 120. At this time, the inclination angle θ2 of the contact end 131c with respect to the connecting end 131b can be in the range of 145 degrees to 175 degrees.

[0093] The bending portion 120 can be provided such that the second contact surface 122 moves toward the second heating blade 131 during secondary pressing, and the pouch wing 12a contacts the second heating blade 131 and the second contact surface 122, respectively. That is, during secondary pressing, the overlapping region 12e of the pouch wing contacts one surface 131d of the contact end 131c of the second heating blade 131 and the second contact surface 122 of the bending portion 120, respectively.

[0094] Through the structure of the contact end 131c of the second heating blade 131 and the bending portion 120 and the heat application method of the present invention, during secondary pressing, the overlapping region 122 is bent within the range of 55 degrees to 85 degrees with respect to the non-overlapping region 12d of the pouch wing 12a, and the upper and lower surfaces of the pouch are simultaneously fired and deformed, so that it is possible to prevent the pouch wing 12a from spreading by 90 degrees or more after the bending process is completed.

[0095] That is, the spring back phenomenon of the pouch wing 12a can be prevented, and the pouch wing 12a can be continuously maintained in a 90-degree bent state.

[0096] Hereinafter, with reference to FIGS. 6 to 10, a method of bending the pouch wing 12a using the pouch wing bending device 100 of a battery cell according to an embodiment of the present invention will be described.

[0097] FIG. 6 is a drawing for explaining a process of bending twice to form an overlapping portion (12e in FIG. 12) having the shape of " JPEG0007694871000002.jpg3138" at the edge of the pouch wing.

[0098] As shown in FIG. 6(a), the battery cell 10 is prepared. At this time, the upper and lower surfaces of the pouch wing of the battery cell 10 are sealed. In FIG. 6(a), the form of the pouch wing 12a of the battery cell is referred to as the initial form.

[0099] Next, as shown in FIG. 6(b), the guide bar 50 supports the pouch wing 12a while pressing the upper and lower surfaces of the pouch wing 12a. Subsequently, the bending block 60 moves (vertically moves) from the lower part to the upper part of the pouch wing 12a and performs a primary bending of the pouch wing 12a by 90 degrees with respect to the initial form.

[0100] Subsequently, as shown in FIG. 6(c), while the bending block 60 moves forward (horizontally moves) toward the battery cell, a secondary bending is performed so that the end portion of the overlapping region of the pouch wing 12a becomes 180 degrees with respect to the initial form.

[0101] FIGS. 7 to 10 are processes of additionally bending the pouch wing 12a after the process described in FIG. 6 is completed. FIGS. 7 to 10 are drawings for explaining the process of bending the pouch wing of the battery cell using the pouch wing bending device of a battery cell according to an embodiment of the present invention.

[0102] That is, a process of bending the overlapping region with respect to the non-overlapping region of the pouch wing 12a is shown.

[0103] Referring to FIGS. 7 and 8, while the second heating blade 131 is in contact with 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, the pouch wing 12a is supported vertically. 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).

[0104] Continuing to refer to FIG. 8, while the bending portion 120 is in contact with the lower surface of the pouch wing 12a, it moves upward (in the first direction, F1) from the initial position.

[0105] As shown in FIG. 9, while the bending portion 120 moves in the second direction F2 toward the upper heating blade 131, it presses the overlapping region of the pouch wing 12a. On the other hand, the first direction (e.g., the vertical direction) and the second direction (e.g., the horizontal direction) can be orthogonal directions.

[0106] Referring to FIG. 9, after the primary pressing is completed, during the secondary pressing, the pouch wing 12a is bent at an acute angle with respect to the non-overlapping region of the overlapping region and undergoes firing deformation. Accordingly, the spring back phenomenon of the pouch wing 12a after bending can be prevented.

[0107] As an example, the temperature applied to the overlapping portion through the bending portion 120 is 160 to 200 ° C, the pressure is 0.2 to 0.7 MPa, and the thermocompression bonding through the bending portion 120 can be performed for 1 to 10 seconds.

[0108] When the bending process of the pouch wing 12a according to FIG. 9 is completed, as shown in FIG. 10, the second heating blade 131, the first heating blade 132, and the bending portion 120 return to their original positions.

[0109] Referring to FIG. 10, after the secondary pressing of the bending portion 120 is completed, the second heating blade 131 is moved in a direction away from the pouch wing 12a, and one surface 131d of the contact end portion 131c of the second heating blade 131 is provided to perform a tertiary press on the pouch wing 12a.

[0110] Referring to FIG. 10, after the secondary pressing of the bending portion 120 is completed, the second heating blade 131 is moved from the initial position in the direction opposite to the direction in which it moved to contact the pouch wing 12a. By moving the second heating blade 131 in a direction away from the pouch wing 12a and pressing the pouch wing 12a in the direction opposite to the second direction F2, the pouch wing 12a can be tertiary bent.

[0111] Referring to FIGS. 10 and 12, during the tertiary bending process, the overlapping portion 12e forms a constant angle θ3 in the range of 75 degrees to 90 degrees with respect to the non-overlapping portion 12d of the pouch wing 12a without an external force being applied.

[0112] Hereinafter, with reference to Table 1 and Table 2, the efficiency of the bending process will be described.

[0113]

Table 1

[0114]

Table 2

[0115] Table 1 shows the improvement rate of the insulation resistance in the case where no heat source is supplied to the heating blade (Case 1) and the case where a heat source is supplied to the heating blade (Case 2).

[0116] In Table 1 above, Case 1 is the insulation resistance improvement rate when the pouch wing 12a is bent using the bending portion 120 with no heat source supplied to the heating blades 131 and 132.

[0117] Case 2 shows the insulation resistance improvement rate when the pouch wing 12a is bent using the block-type bending portion 120 with heat sources supplied to the heating blades 131 and 132.

[0118] In Table 1 and Table 2, the insulation resistance range is a range set based on the block type, and is largely divided into a range of 1 MΩ to 49 MΩ, a range of 50 MΩ to 99 MΩ, and 100 MΩ or more.

[0119] In Case 1, the bending portion 120 having a block-type structure according to an embodiment of the present invention shows that the insulation resistance value in the range of 1 MΩ to 49 MΩ before bending is improved by an average of 317% after bending, the insulation resistance value in the range of 50 MΩ to 99 MΩ before bending is improved by an average of 534% after bending, and the insulation resistance value in the range of 100 MΩ before bending is improved by an average of 186% after bending.

[0120] In Case 2, the bending portion 120 having a block-type structure according to an embodiment of the present invention shows that the insulation resistance value in the range of 1 MΩ to 49 MΩ before bending is improved by an average of 373% after bending, the insulation resistance value in the range of 50 MΩ to 99 MΩ before bending is improved by an average of 652% after bending, and the insulation resistance value in the range of 100 MΩ before bending is improved by an average of 221% after bending.

[0121] Referring to Case 1 and Case 2, it can be seen that in the present invention, the insulation resistance is improved by at least twice or more by the block-type bending portion 120 when comparing before and after bending.

[0122] Table 2 summarizes the average increase / decrease rate of the insulation resistance of Cases 1 and 2 in Table 1 and the insulation resistance improvement rate due to the heat supply of the heating blade. Here, Cases 1 and 2 were experimented under the same conditions.

[0123] Referring to Table 2 and examining the improvement rate of Case 2 with respect to Case 1 in detail, when heat is supplied to the heating blade (Case 2), compared with the case where no heat is supplied to the heating blade (Case 1), the improvement rate is 18% in the range of 1 MΩ to 49 MΩ, 22% in the range of 50 MΩ to 99 MΩ, and 19% at 100 MΩ or more, indicating that the insulation resistance is improved.

[0124] Those with ordinary knowledge in the technical field to which the present invention pertains will be able to understand that the present invention can be implemented in other specific forms without changing its technical idea and essential features.

[0125] Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

[0126] The scope of the present invention is indicated by the claims described below rather than the above detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present invention.

Industrial Applicability

[0127] The present invention can melt the sealing portion of the pouch wing through a pair of heating blades, preventing and removing the generation of cracks at the sealing portion during the bending process of the pouch wing. Accordingly, the present invention can improve the insulation resistance performance of the battery cell by preventing poor insulation resistance due to cracks at the sealing portion.

Claims

1. A mounting portion where the battery cell is mounted such that the pouch wings of the battery cell are exposed to the outside; A pair of heating blades arranged to face each other at a predetermined interval and provided so as to be movable into contact with the pouch wings and provided to heat the pouch wings; and A bending process section provided to bend the pouch wings by moving along a first direction in a state where the pair of heating blades are in contact with the pouch wings to perform primary pressing on the pouch wings and moving along a second direction different from the first direction to perform secondary pressing on the pouch wings, the bending process section being included in a device for bending the pouch wings of a battery cell.

2. The size of the bending angle of the pouch wings during the primary pressing by the bending process section is larger than the size of the bending angle during the secondary pressing. The device for bending the pouch wings of a battery cell according to Claim 1.

3. The bending process section is a heating block provided to supply heat to the pouch wings. The device for bending the pouch wings of a battery cell according to Claim 1.

4. The bending process section is provided so as to be capable of surface contact with the pouch wings when pressing the pouch wings. The device for bending the pouch wings of a battery cell according to Claim 3.

5. The bending process section A first contact surface that contacts the first surface of the pouch wings at an initial position for the primary pressing, and Having 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 wings during the secondary pressing. The device for bending the pouch wings of a battery cell according to Claim 4.

6. The bending process section has a curved portion that curves at a predetermined curvature to connect the first contact surface and the second contact surface. The device for bending the pouch wings of a battery cell according to Claim 5.

7. When the bending portion moves along the first direction in a state where the first contact surface contacts the first surface of the pouch wing, the first contact surface, the curved portion, and the second contact surface sequentially contact the first surface of the pouch wing. The pouch wing bending device for a battery cell according to claim 6.

8. The bending portion is provided such that the second contact surface is inclined within a range of 55 degrees to 85 degrees with respect to the first contact surface. The pouch wing bending device for a battery cell according to claim 5.

9. The pair of heating blades includes a first heating blade that contacts the first surface of the pouch wing and a second heating blade that contacts the second surface in a direction opposite to the first surface of the pouch wing. During the secondary pressing, the bending portion is provided such that 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. The pouch wing bending device for a battery cell according to claim 5.

10. The first heating blade and the second heating blade each include a main body that contacts the pouch wing and a heat supply source that provides heat to the main body. The contact end portion of the main body of the second heating blade that contacts the pouch wing is bent in a direction toward the bending portion. The pouch wing bending device for a battery cell according to claim 9.

11. The second heating blade is bent such that one surface of the contact end portion is parallel to the second contact surface of the bending portion. The pouch wing bending device for a battery cell according to claim 10.

12. After the secondary pressing of the bending portion is completed, the second heating blade is moved in a direction away from the pouch wing, and one surface of the contact end portion of the second heating blade is provided to perform a tertiary pressing on the pouch wing. The pouch wing bending device for a battery cell according to claim 11.

13. After the secondary pressing of the bending portion is completed, the second heating blade is moved in a direction opposite to the direction in which it moved to contact the pouch wing, the pouch wing bending device for a battery cell according to claim 12.

14. The second heating blade is moved in a direction away from the pouch wing, and the pouch wing is tertiary bent by pressing the pouch wing in a direction opposite to the second direction, the pouch wing bending device for a battery cell according to claim 12.

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