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

Abstract

The present invention relates to a pouch-type battery cell, a pouch wing bending device of a battery cell, and a method of bending a pouch wing of a battery cell, and more particularly, to a pouch-type battery cell, a pouch wing bending device of a battery cell, and a method of bending a pouch wing of a battery cell, which can improve the insulation resistance performance of a battery cell by bending a pouch wing while heat-treating a sealed portion of the pouch wing of a battery cell, thereby preventing and removing cracks in the sealed portion.

Description

Technical Field

[0001] This invention relates to a pouch-type battery cell, a device for bending the pouch wings of the battery cell, and a method for bending the pouch wings in the battery cell. Specifically, it relates to a pouch-type battery cell, a device for bending the pouch wings of the battery cell, and a method for bending the pouch wings in the battery cell, wherein the pouch-type battery cell can improve the insulation resistance performance of the battery cell by bending the pouch wings while heat-treating the sealing portion of the pouch wings in the battery cell, thereby preventing and removing cracks in the sealing portion.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0109811, filed on August 20, 2021, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] Secondary batteries, often referred to as lithium secondary batteries, are batteries that have a polymer electrolyte and generate current through the movement of lithium ions, with secondary battery pouches used as the casing material for encapsulating such batteries.

[0004] exist Figure 1 In the diagram, the general structure of a pouch-type secondary battery is schematically illustrated as an exploded perspective view.

[0005] Reference Figure 1 The pouch-type secondary battery (or battery cell) 10 is configured to include: an electrode assembly 13; electrode tabs 14 and 15 extending from the electrode assembly 13; electrode leads welded to the electrode tabs 14 and 15; and a secondary battery pouch 12 for accommodating the electrode assembly 13.

[0006] Electrode assembly 13 is a power generating element consisting of a stacked or stacked / folded structure in which positive and negative electrodes are sequentially laminated with a diaphragm inserted between them. Electrode contacts 14 and 15 extend from each electrode plate of electrode assembly 13.

[0007] Electrode leads 16 and 17 are electrically connected, for example, by soldering to a plurality of electrode tabs 14 and 15 extending from each electrode plate, with a portion of them exposed to the outside of the secondary battery pouch 12. Furthermore, to increase the sealing of the secondary battery pouch 12 while simultaneously ensuring electrical insulation, insulating films 18 are attached to portions of the upper and lower surfaces of the electrode leads 16 and 17.

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

[0009] The secondary battery bag protects the battery cell, which consists of an electrode assembly and an electrolyte introduced into it through a subsequent process. In order to supplement the electrochemical characteristics of the battery cell and improve heat dissipation, it is constructed in the form of an inserted aluminum thin film.

[0010] To protect the battery cells from external impacts, functional polymer films such as polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, nylon resin, or liquid crystal polymer (LCP) resin are formed on the outer layer of the aluminum film.

[0011] In the bag, the upper bag and the lower bag are joined on the outer peripheral surfaces by means of heat fusion or the like, wherein, in order to adhere to each other, an adhesive layer is formed between the lower surface of the upper bag and the upper surface of the lower bag, which is a polyolefin such as polyethylene (PE), cast polypropylene (cPP) or polypropylene (PP), or copolymers thereof.

[0012] This pouch battery undergoes steps such as housing the electrode assembly in a laminate, injecting electrolyte, and sealing it by heat fusion, and also undergoes a process of housing the outer peripheral surface of the battery cell or the heat-fused portion (sealing portion) in a bending device, and then pressing the sealing portion to bend it so that the sealing portion is bent vertically to make close contact with the side wall of the housing.

[0013] However, when the sealing part is bent vertically by the bending device, the bent part recovers over time, which leads to defects in the battery cell size design, resulting in the need to repeat the operation.

[0014] Korean Patent Publication No. 10-2015-0035123 relates to a battery cell bending device including a heating member. A method for bending the outer peripheral surface of a battery cell using a battery cell bending device according to the prior art will be briefly described below.

[0015] Figure 2 This is a sequence diagram illustrating a bending method for the pouch wings in a bent battery cell according to the prior art, and Figure 3 The diagram illustrates the state of the seal after the bag wings have been bent, according to existing technology.

[0016] like Figure 2As shown, the battery cell is placed on the battery cell bending device, and the outer peripheral surface of the battery cell is bent. In the battery cell 10, a bag wing 12a is formed in the direction of the outer peripheral surface of the receiving portion during the heat fusion process, wherein the process is the process of bending the bag wing 12a.

[0017] The battery cell 10 is mounted on the substrate 20 formed in the battery cell bending device, such that the bent portion of the bag wing 12a is fixed by the bending guides 21 and 22, and the pressing rollers 31 and 32 move downward to bend the bag wing 12a vertically downward.

[0018] At this time, the bag wing 12a of the battery unit 10 is bent, and at the same time the bag wing 12a is heated by the heating members 41, 42 installed on the adjacent parts of the pressing rollers 31, 32 so as to make close contact with the side wall of the battery unit.

[0019] The battery cell bending device, including the heating member disclosed in Korean Patent Publication No. 10-2015-0035123, uses a heating member to vertically bend the outer peripheral surface of the battery cell to make close contact with the side wall of the receiving part, thereby solving the problem of defects that may occur in the design of battery cell size due to the bending part recovering over time.

[0020] In the above method, because the sidewalls of the battery cell are not heated, heat is not sufficiently provided to the sealed area of ​​the battery cell, resulting in non-melting portions of the seal. For this reason, multiple microcracks are generated in the seal of the bag wing, thus posing a risk of insulation defects.

[0021] Insulation resistance indicates the degree of insulation between the aluminum pouch in the battery bag and the battery. For example... Figure 3 As shown, an insulation defect occurs because multiple microcracks 12c in the sealing portion 12b of the bag wing cause current to flow between the aluminum bag and the battery. Here, the sealing portion 12b refers to the area where the bag wing is attached with weak adhesion before sealing.

[0022] If many battery cells with poor insulation resistance are discharged, the equipment is expected to malfunction due to the complete discharge sensor's detection, resulting in concerns about production losses. Here, when a battery cell does not meet the specifications specified by the equipment during the battery cell manufacturing process, the battery cell is identified as defective and discharged. If the discharge port becomes full due to the discharge of defective cells, the complete discharge sensor generates an alarm and the equipment malfunctions.

[0023] In addition, when the sealing portion of the pouch wing in the battery cell is fixed with tape and adjacent to the electrode assembly side, a difference in the total width between the tape-attached portion and the unattached portion is inevitable, resulting in process losses. Summary of the Invention

[0024] Technical issues

[0025] The present invention aims to provide a pouch-type battery cell, a pouch wing bending device for the battery cell, and a method for bending the pouch wing in the battery cell. The pouch-type battery cell can improve the insulation resistance performance of the battery cell by bending the pouch wing while heat-treating the sealing portion of the pouch wing in the battery cell, thereby preventing and removing cracks in the sealing portion.

[0026] Technical solution

[0027] To address the aforementioned problems, according to one aspect of the present invention, a bending device for a battery cell's pouch wing is provided, comprising: 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, the pair of heating blades being arranged to face each other and spaced apart by a predetermined interval, movably disposed to contact the pouch wing, and configured to heat the pouch wing; and a bending processing portion, the bending processing portion being configured to bend the pouch wing by moving along a first direction to press the pouch wing once while the pair of heating blades are in contact with the pouch wing, and by moving along a second direction different from the first direction to press the pouch wing a second time.

[0028] Furthermore, the bending angle of the bag wing when the bag wing is pressed once by the bending processing section can be greater than the bending angle when the bag wing is pressed twice.

[0029] In addition, the bending processing section may be a heating block configured to provide heat to the bag wings.

[0030] Furthermore, the bending processing section may be configured to make surface contact with the bag wing when the bag wing is pressed.

[0031] In addition, the bending processing part may have a first contact surface that contacts the first surface of the bag wing at the initial position of the first press; and a second contact surface that is inclined at an acute angle relative to the first contact surface and contacts the first surface of the bag wing during the second press.

[0032] Furthermore, the bending processing section may have a curved portion that is bent at a predetermined curvature to connect the first contact surface to the second contact surface.

[0033] Furthermore, when the bending processing section moves along the first direction while the first contact surface is in contact with the first surface of the bag wing, it can be configured such that the first contact surface, the curved portion, and the second contact surface sequentially contact the first surface of the bag wing.

[0034] Furthermore, the bending processing section can be configured such that the second contact surface is inclined relative to the first contact surface in the range of 55 degrees to 85 degrees.

[0035] Furthermore, the pair of heating blades may include a first heating blade that contacts the first surface of the bag wing and a second heating blade that contacts the second surface in the opposite direction to the first surface of the bag wing.

[0036] Furthermore, the bending processing section may be configured such that during the second pressing, the second contact surface moves toward the second heating blade, and the bag wing portion contacts the second heating blade and the second contact surface respectively.

[0037] In addition, the first heating blade and the second heating blade may each include a body that contacts the bag wing and a heat source for providing heat to the body.

[0038] Furthermore, the second heating blade can be bent along the contact end of the main body that contacts the bag wing toward the bending processing section.

[0039] Furthermore, the second heating blade can be bent such that one side of the contact end is parallel to the second contact surface of the bending process portion.

[0040] Furthermore, after the second pressing of the bending process is completed, the second heating blade can be configured to move in a direction away from the bag wing, and one side of the contact end of the second heating blade presses the bag wing three times.

[0041] Furthermore, after the second pressing of the bending process is completed, the second heating blade can be configured to move in the opposite direction to the direction of movement to contact the bag wing.

[0042] Furthermore, when the second heating blade moves away from the bag wing and presses the bag wing in the opposite direction to the second direction, the bag wing is bent three times.

[0043] Furthermore, according to another aspect of the invention, a pouch-type battery cell includes: an electrode assembly; and a pouch for housing the electrode assembly. The pouch includes pouch wings sealed to the outside of the electrode assembly, wherein the pouch wings are repeatedly bent to include overlapping and non-overlapping portions, and in the absence of applied external force, the overlapping portions form a constant angle within the range of 75 to 90 degrees relative to the non-overlapping portions.

[0044] Furthermore, according to another aspect of the present invention, a method for bending a pouch wing in a battery cell is provided, comprising: bending the pouch wing at least twice in different directions using a pouch wing bending device of the battery cell.

[0045] Beneficial effects

[0046] As described above, at least one example of the present invention relates to a pouch-type battery cell, a pouch wing bending device for the battery cell, and a method for bending the pouch wing in the battery cell, which has the following functional effects.

[0047] This invention prevents and removes cracks in the sealing portion of the bag wing by melting the sealing portion of the bag wing with a pair of heating blades during the bending process. Therefore, this invention improves the insulation resistance performance of the battery cell by preventing insulation resistance defects caused by cracks in the sealing portion.

[0048] This invention prevents the bag wings from opening to 90 degrees or more because it incorporates an inverted trapezoidal block structure with a bending processing section, and a structure in which the bending processing section engages with an upper heating blade to push the bag wings at a predetermined angle toward the upper heating blade during bending. Furthermore, the bag wings undergo plastic deformation while bending further inward. Therefore, this invention can continuously maintain the 90-degree bending state of the bag wings by preventing springback.

[0049] Then, compared with the conventional roller structure, the bending processing section has a block structure that can bend the bag wings while making surface contact with the bag wings, thereby widening the contact area between the bending processing section and the bag wings, so that the present invention can bend the bag wings more stably compared with the prior art.

[0050] When a curved section is provided in the bending process section, the present invention can minimize friction with the bag wings, just as a conventional pressing roller pushes the bag wings upward, and pushes the bag wings upward without damaging the bag wings, so that the bag wings bend at a predetermined angle.

[0051] Due to the structural features described above, the present invention can improve insulation resistance performance two or more times compared to bending the bag wings in a conventional roller type. Attached Figure Description

[0052] Figure 1 This is an exploded perspective view of the general structure of a pouch battery.

[0053] Figure 2 This is a sequence diagram illustrating a bending method for the pouch wings in a bent battery cell according to the prior art.

[0054] Figure 3 The diagram illustrates the state of the seal after the bag wings have been bent, according to existing technology.

[0055] Figure 4 This is a schematic diagram illustrating the construction of a bag wing bending device for a battery cell according to an example of the present invention.

[0056] Figure 5 This is a schematic cross-sectional view illustrating a bending process according to an example of the present invention.

[0057] Figures 6 to 10 This is a diagram illustrating the process of bending the pouch wings in a battery cell using a pouch wing bending device according to an example of a battery cell based on the present invention.

[0058] Figure 11 The illustration shows the state of the seal after the bag wing has been bent, according to an example of the invention.

[0059] Figure 12 This is a diagram illustrating the pouch wing of a pouch-type battery cell according to an example of the present invention. Detailed Implementation

[0060] Hereinafter, a preferred embodiment of the pouch-type battery cell and the pouch wing bending device of the battery cell according to the present invention will be described with reference to the accompanying drawings.

[0061] Figure 4 This is a structural diagram of a battery cell pouch wing bending device according to an example of the present invention, and Figure 5 This is a schematic cross-sectional view of a bending section according to an example of the present invention.

[0062] Figures 6 to 10 This is a diagram illustrating the process of bending the pouch wings in a battery cell using a pouch wing bending device according to an example of a battery cell based on the present invention.

[0063] also, Figure 11 The illustration shows the state of the seal after the bag wing has been bent, according to an example of the invention. Figure 12 This is a diagram illustrating the pouch wing of a pouch-type battery cell according to an example of the present invention.

[0064] If passed Figure 1As described, the pouch-type battery cell 10 includes an electrode assembly 13 and a pouch 12 that houses the electrode assembly 13.

[0065] The bag 12 includes a bag wing 12a that is sealed to the outside of the electrode assembly 13. Furthermore, refer to... Figure 12 The bag wing 12a is bent multiple times to include an overlapping portion 12e and a non-overlapping portion 12d, and in the absence of an applied external force, the overlapping portion 12e forms a constant angle θ3 relative to the non-overlapping portion 12d in the range of 75 degrees to 90 degrees.

[0066] The sealed bag wing 12a has three curved points along the direction toward the edge, and has approximately on the outer side... The overlapping portion 12e of the character shape, and the bag wing 12a has a non-overlapping portion 12d in the region near the electrode assembly side.

[0067] Furthermore, the state in which no external force is applied refers to the state in which the bag wing 12a is not wrapped with tape or the like.

[0068] That is, when the bending process of the bag wing 12a is completed by the bag wing bending device 100 of the battery cell as described herein, the overlapping portion 12e in the bag wing 12a can be maintained at a constant angle θ3 in the range of 75 degrees to 90 degrees relative to the non-overlapping portion 12d. Preferably, the overlapping portion 12e in the bag wing 12a can be maintained at a constant angle θ3 in the range of 80 degrees to 90 degrees relative to the non-overlapping portion 12d.

[0069] According to an example of the present invention, the pouch wing bending device 100 of the battery cell is a device for bending the pouch wing 12a in the battery cell 10.

[0070] Reference Figure 4 The battery cell's pouch wing bending device 100 includes a placement part 110, a bending processing part 120, and a pair of heating blades 131 and 132.

[0071] The battery unit 10 is placed on the mounting portion 110, such that the pocket wing portion 12a of the battery unit is exposed to the outside. Specifically, the battery unit 10 is placed on the mounting portion 110, such that the pocket wing portion 12a is exposed laterally.

[0072] In addition, a pair of heating blades 131, 132 and a bending processing section 120 are installed to be separated from the mounting section 110 in the lateral direction of the mounting section 110.

[0073] A pair of heating blades 131, 132 are arranged to face each other and separated by a predetermined interval. In addition, the pair of heating blades 131, 132 are movably arranged to contact the bag wing 12a, and are configured to heat the bag wing 12a when in contact with it.

[0074] The bag wing 12a may have a first surface 12f and a second surface 12g opposite to the first surface 12f. In this case, a pair of heating blades 131, 132 may include a first heating blade 132 that contacts the first surface 12f of the bag 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 bag wing.

[0075] At this point, in this file, based on Figure 4 The arrangement of the components shown indicates that the second heating blade 131 can be referred to as the upper heating blade, and the first heating blade 132 can be referred to as the lower heating blade. Furthermore, the pair of heating blades 131 and 132 respectively contact the non-overlapping portion 12d of the bag wing 12a.

[0076] When the pair of heating blades 131 and 132 move along the first direction F1, the bending processing unit 120 is configured to bend the bag wing 12a while in contact with it, thereby pressing the bag wing 12a once. It then moves along a second direction F2, different from the first direction F1, to press the bag wing 12a a second time. The bending processing unit 120 can be configured to bend the bag wing 12a twice in different directions.

[0077] The bending angle of the bag wing when it is pressed once by the bending processing section 120 can be greater than the bending angle when it is pressed twice.

[0078] The bag wing bending device 100 may further include a control unit for controlling the movement of the bending processing unit 120 and operating the heating.

[0079] Reference Figure 4 In the initial position before the bending process, the bending processing unit 120 is located below the first surface 12f of the bag wing 12a. The bending processing unit 120 contacts the first surface 12f of the bag wing 12a in the initial position to bend the bag wing 12a in one motion as it moves to the upper part of the initial position. Furthermore, the bending processing unit 120 is configured to provide heat to the bag wing 12a.

[0080] The bending section 120 may be a heating block configured to provide heat to the bag wing section 12a. The bending section 120 includes a heat source therein, which may be a self-heating heating rod (Cartridge Heater Pipe). Furthermore, one or more heating rods are included inside the bending section 120, wherein the interior of the heating rod may include a ceramic core forming the shape of the heating rod and simultaneously serving as a support rod, a heating coil surrounding the ceramic core, and wires for supplying power to the heating coil.

[0081] Reference Figure 5 The bending section 120 can be configured to make surface contact with the bag wing 12a when the bag wing 12a is pressed. That is, the bending section 120 has a flat, block-shaped structure on the surface that contacts the bag wing 12a when pressed. As an example, the bending section 120 can have a generally inverted trapezoidal cross-section.

[0082] In this document, during the first and second presses, the bending processing section 120 has different surfaces that contact the bag wing section 12a, respectively, wherein the corresponding contact surfaces may be referred to as the first contact surface 121 and the second contact surface 122. The bending processing section may have a first contact surface 121 and a second contact surface 122. The first contact surface 121 contacts the first surface 12f of the bag wing section 12a at the initial position for the first press, and the second contact surface 122 is inclined at an acute angle relative to the first contact surface 121 and contacts the first surface 12f of the bag wing section 12a during the second press.

[0083] The first contact surface 121 is the surface on which the bending part 120 contacts the bag wing 12a when placed in the initial position and moves upward from the initial position. The second contact surface 122 is the surface on which the bending part 120 contacts the bag wing 12a during a second press. The second contact surface 122 bends downward and extends towards the lower part of the first contact surface 121. In particular, during the second press, the second contact surface 122 contacts the overlapping portion 12e of the bag wing 12a.

[0084] The second contact surface 122 is bent to be tilted at a predetermined angle relative to the first contact surface 121. At this time, the bending processing section 120 can be configured to have an inclination angle θ1 of the second contact surface 122 relative to the first contact surface 121 in the range of 55 degrees to 85 degrees.

[0085] Therefore, due to the inclined structure of the second contact surface 122 of the bending section 120 relative to the first contact surface 121, the opening of the bag wing 12a by 90 degrees or more can be prevented. This is because when the bag wing 12a bends, it is pushed at a predetermined angle towards the upper heating blade 131, and undergoes plastic deformation while bending further inward (towards the electrode assembly). In other words, by preventing the springback phenomenon of the bag wing 12a, the bag wing 12a can continuously maintain a 90-degree bent state.

[0086] Furthermore, the bending section 120 may have a curved portion 123, which is bent at a predetermined curvature to connect the first contact surface 121 and the second contact surface 122. In this structure, refer to... Figure 4The tilt angle θ1 of the second contact surface 122 relative to the first contact surface 121 can refer to the angle formed at the intersection of imaginary line segments extending from the respective contact surfaces.

[0087] Compared to conventional roller structures, the bending processing section 120 has a block-shaped structure that allows it to bend the bag wing 12a while making surface contact with it during both the first and second presses. Furthermore, the increased contact area between the bending processing section 120 and the bag wing 12a during pressing enables the bending processing section 120 to bend the bag wing 12a stably.

[0088] Furthermore, the bending section 120 has a curved portion 123. The curved portion 123 can be formed by rounding the portion connecting the first contact surface 121 and the second contact surface 122.

[0089] While the first contact surface 121 is in contact with the first surface 12f of the bag wing 12a, the bag wing 12a straddles the curved portion 123 and moves upward (in the first direction, F1) from the initial position to contact the second contact surface 122, while the bending processing section 120 bends the bag wing 12a.

[0090] At this time, the bending processing section 120 can minimize the friction with the bag wing 12a through the curved portion 123, and push the bag wing 12a upward without damaging it, just like a conventional pressing roller pushes the bag wing 12a upward, so that the bag wing 12a bends at a predetermined angle.

[0091] When the first contact surface 121 is in contact with the first surface 12f of the bag wing, and the bending processing part 120 moves along the first direction F1, the first contact surface 121, the curved portion 123, and the second contact surface 122 can sequentially contact the first surface 12f of the bag wing 12a.

[0092] Reference Figure 4 A pair of heating blades 131 and 132 are movably arranged facing each other, such that they respectively contact the first surface (12f, also referred to as the "lower surface") and the second surface (12g, also referred to as the "upper surface") of the bag wing 12a.

[0093] Additionally, in this example, the portion of the bag wing 12a that contacts the pair of heating blades 131, 132 can be referred to as a sealing portion. (See reference...) Figure 11 The sealing part 12b can be formed by applying heat via a pair of heating blades 131, 132.

[0094] A pair of heating blades 131, 132 are configured to move in a direction close to the bag wing 12a and in a direction away from the bag wing 12a. For example, the pair of heating blades 131, 132 have a structure that can be raised and lowered. While providing heat to the bag wing 12a, the pair of heating blades 131, 132 also perform the function of holding the bag wing 12a during the bending process.

[0095] The present invention uses a pair of heating blades 131, 132 to melt the sealing part of the bag wing 12a (see...). Figure 11 12b) can prevent cracks from forming in the sealing part 12b during the bending process of the bag wing 12a.

[0096] The corresponding heating blades 131 and 132 each include a body 131b and 132b that contacts the bag wing 12a; and a heat source 131a and 132a for providing heat to the body 131b and 132b. The body 131b and 132b may extend from the heat source 131a and 132a.

[0097] The upper second heating blade 131 includes an upper heat source 131a; and a body 131b and 131c extending from the upper heat source 131a, wherein the body includes a connection end 131b connected to the upper heat source 131a and a contact end 131c extending from the connection end 131b.

[0098] The lower heating blade 132 includes a lower heat source 132a and a body 132b extending from the lower heat source 132a, wherein the body includes a contact end for contacting the bag wing 12a.

[0099] Here, the contact end 132b has a structure that allows the sealing portion 12b to be pressed by contacting the bag wing portion 12a. The main bodies of the heating blades 131 and 132 may each have a rod shape.

[0100] In addition, the second heating blade 131 located at the top has a contact end 131c of the main body corresponding to the shape of the bending processing section 120.

[0101] The second heating blade 131 has a shape in which the contact end 131c of the main body, which contacts the bag wing portion 12a, is bent in the direction toward the bending processing portion 120. Specifically, the second heating blade 131 can be bent such that one side 131d of the contact end 131c is parallel to the second contact surface 122 of the bending processing portion 120. One side 131d of the contact end 131c is the surface that contacts one side (12h, the surface facing the electrode assembly) of the overlapping portion 12e of the bag wing portion during the second press of the bending processing portion 120.

[0102] As an example, when the bending section 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 relative to the connecting end 131b to correspond to the shape of the bending section 120. In this case, the tilt angle θ2 of the contact end 131c relative to the connecting end 131b can be in the range of 145 degrees to 175 degrees.

[0103] The bending section 120 can be configured such that, during a second press, the second contact surface 122 moves toward the second heating blade 131, and the bag wing 12a contacts the second heating blade 131 and the second contact surface 122, respectively. That is, during a second press, the overlapping portion 12e of the bag wing contacts one side 131d of the contact end 131c of the second heating blade 131 and the second contact surface 122 of the bending section 120, respectively.

[0104] After the bending process is completed, the present invention can prevent the bag wing 12a from opening 90 degrees or more, because through the structure of the contact end 131c of the second heating blade 131 and the bending processing part 120, as well as the heat application method, when the bag is pressed for the second time, the upper and lower surfaces of the bag undergo plastic deformation while the overlapping part 12e bends in the range of 55 degrees to 85 degrees relative to the non-overlapping part 12d that does not overlap with the bag wing 12a.

[0105] In other words, by preventing the springback phenomenon of the bag wing 12a, the bag wing 12a can continuously maintain a 90-degree bending state.

[0106] In the following text, reference will be made to Figures 6 to 10 A method for bending the bag wing 12a using a bag wing bending device 100 of a battery cell according to an example of the present invention is described.

[0107] Figure 6 This is used to explain the formation of two bends at the edge of the bag wing. Overlapping parts of character shapes ( Figure 12 A diagram illustrating process 12e).

[0108] like Figure 6 As shown in (a), battery cell 10 is fabricated. At this time, the pouch flaps of battery cell 10 are sealed on both the upper and lower surfaces. Figure 6 In (a), the shape of the pouch wing 12a in the battery cell is referred to as the initial shape.

[0109] Next, as Figure 6As shown in (b), the guide rod 50 holds the bag wing 12a while pressing the upper and lower surfaces of the bag wing 12a. Then, as the bending block 60 moves from the lower part to the upper part of the bag wing 12a (vertical movement), the bag wing 12a is bent 90 degrees relative to its initial shape in one motion.

[0110] After that, as Figure 6 As shown in (c), while the bending block 60 moves forward toward the battery cell (horizontal movement), the bag wing 12a is bent a second time, such that the end of the overlapping area is 180 degrees relative to the initial shape.

[0111] Figures 7 to 10 In completing Figure 6 The process described in the text is followed by a further bending of the bag wing 12a. Figures 7 to 10 This is a diagram illustrating the process of bending the bag wings of a battery cell using a bag wing bending device according to an example of the present invention.

[0112] That is, in the bag wing 12a, a process of bending the overlapping area relative to the non-overlapping area is shown.

[0113] Reference Figure 7 and Figure 8 While the second heating blade 131 is positioned to contact the upper surface of the bag wing 12a, the first heating blade 132 is positioned to contact the lower surface of the bag wing 12a, holding the bag wing 12a in place. At this time, the second heating blade 131 and the first heating blade 132 provide heat to the bag wing 12a. The sealing portion of the bag wing 12a (see...) Figure 11 12b) is melted by the second heating blade 131 and the first heating blade 132.

[0114] Then, refer to Figure 8 The bending processing section 120 moves from its initial position to the upper part (first direction, F) while contacting the lower surface of the bag wing section 12a.

[0115] like Figure 9 As shown, the bending processing section 120 presses the overlapping area of ​​the bag wing 12a while moving toward the upward heating blade 131 in the second direction F2. Furthermore, the first direction (e.g., vertical direction) and the second direction (e.g., horizontal direction) can be orthogonal to each other.

[0116] Reference Figure 9 When a second press is performed after the first press, the bag wing 12a undergoes plastic deformation as the overlapping area bends at an acute angle relative to the non-overlapping area. Therefore, the springback phenomenon of the bag wing 12a after bending can be prevented.

[0117] As an example, the temperature applied to the overlapping portion by the bending processing section 120 is 160 to 200°C, and the pressure is 0.2 to 0.7 MPa, wherein the thermal compression by the bending processing section 120 can be performed for 1 to 10 seconds.

[0118] When completed according to Figure 9 During the bending process of the bag wing 12a, the second heating blade 131, the first heating blade 132, and the bending processing section 120 return to their initial positions, such as Figure 10 As shown in the image.

[0119] Reference Figure 10 After the bending processing section 120 completes the second press, the second heating blade 131 moves away from the bag wing 12a and is configured such that one side 131d of the contact end 131c of the second heating blade 131 presses the bag wing 12a three times.

[0120] Reference Figure 10 After the bending process section 120 completes the second pressing, the second heating blade 131 moves from the initial position in the opposite direction to the direction of movement to contact the bag wing 12a. The second heating blade 131 moves away from the bag wing 12a and presses the bag wing 12a in the opposite direction to the second direction F2, thereby the bag wing 12a can be bent three times.

[0121] Reference Figure 10 and Figure 12 Through three bending processes, without the application of external force, the overlapping portion 12e of the bag wing 12a forms a constant angle θ3 relative to the non-overlapping portion 12d within the range of 75 to 90 degrees.

[0122] The efficiency of the bending process will be described below with reference to Tables 1 and 2.

[0123] [Table 1]

[0124]

[0125] [Table 2]

[0126]

[0127] Table 1 shows the rate of increase in insulation resistance value in the case where the heat source is not provided by the heating blades (Case 1) and in the case where the heat source is provided by the heating blades (Case 2).

[0128] In Table 1 above, Case 1 is the rate of increase in insulation resistance when the bending processing section 120 bends the bag wing 12a without providing a heat source to the heating blades 131 and 132.

[0129] Then, scenario 2 shows the rate of increase in insulation resistance when the bag wing 12a is bent using the block bending processing section 120 while a heat source is provided to the heating blades 131 and 132.

[0130] In Tables 1 and 2 above, the insulation resistance value ranges are set based on the block type, and are mainly divided into the range of 1MΩ to 49MΩ, the range of 50MΩ to 99MΩ, and 100MΩ or greater.

[0131] In Case 1, it can be seen that in the bending section 120 with a block structure according to an example of the present invention, the insulation resistance value in the range of 1 MΩ to 49 MΩ before bending is increased by an average of 317% after bending; the insulation resistance value in the range of 50 MΩ to 99 MΩ before bending is increased by an average of 534% after bending; and the insulation resistance value in the range of 100 MΩ or greater before bending is increased by an average of 186% after bending.

[0132] In case 2, it can be seen that in the bending section 120 with a block structure according to an example of the present invention, the insulation resistance value in the range of 1 MΩ to 49 MΩ before bending is increased by an average of 373% after bending; the insulation resistance value in the range of 50 MΩ to 99 MΩ before bending is increased by an average of 652% after bending; and the insulation resistance value in the range of 100 MΩ or greater before bending is increased by an average of 221% after bending.

[0133] Referring to Situations 1 and 2 above, it can be seen that in the present invention, due to the block bending processing part 120, the insulation resistance value is increased by at least two times compared with that before and after bending.

[0134] Table 2 summarizes the average increase-decrease rate of insulation resistance values ​​in Situations 1 and 2 of Table 1, as well as the rate of increase in insulation resistance values ​​due to the heat provided by the heating blades. Here, Situations 1 and 2 were tested under the same conditions.

[0135] Referring to Table 2 to observe the improvement rate of Case 2 relative to Case 1, it can be seen that, compared with the case where no heat is supplied to the heating blades (Case 1), the insulation resistance is increased by 18% in the range of 1MΩ to 49MΩ, 22% in the range of 50MΩ to 99MΩ, and 19% in the range of 100MΩ or greater when heat is supplied to the heating blades (Case 2).

[0136] Those skilled in the art to which this invention pertains will understand that the invention can be implemented in other specific forms without altering its technical spirit or essential features.

[0137] Therefore, it should be understood that the above embodiments are illustrative in all respects and not restrictive.

[0138] The scope of this invention is defined by the following claims rather than the detailed description above, and all variations or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included within the scope of this invention.

[0139] Industrial applicability

[0140] This invention prevents and removes cracks in the sealing portion of the bag wing by melting the sealing portion of the bag wing with a pair of heating blades during the bending process. Therefore, this invention improves the insulation resistance performance of the battery cell by preventing insulation resistance defects caused by cracks in the sealing portion.

Claims

1. A device for bending the pouch wing of a battery cell, characterized in that, include: The battery cell is placed on the mounting part, such that the pouch wings of the battery cell are exposed to the outside; A pair of heating blades, the pair of heating blades being configured to face each other and spaced apart by a predetermined interval, being movably configured to contact the bag wings, and being configured to heat the bag wings; as well as The bending processing unit is configured to bend the bag wing by moving along a first direction to press the bag wing once while the pair of heating blades are in contact with the bag wing, and by moving along a second direction different from the first direction to press the bag wing a second time. The portion of the bag wing that contacts the pair of heating blades forms a seal by applying heat via the pair of heating blades, and the seal is melted by the pair of heating blades.

2. The battery cell pouch wing bending device according to claim 1, characterized in that, The bending angle of the bag wing is greater when the bag wing is pressed once by the bending processing section than when it is pressed twice.

3. The battery cell pouch wing bending device according to claim 1, characterized in that, The bending processing section is a heating block configured to provide heat to the bag wings.

4. The battery cell pouch wing bending device according to claim 3, characterized in that, The bending processing section is configured to make surface contact with the bag wing when the bag wing is pressed.

5. The battery cell pouch wing bending device according to claim 4, characterized in that, The bending processing part has A first contact surface, which contacts the first surface of the bag wing at the initial position of the first press; and A second contact surface is inclined at an acute angle relative to the first contact surface and contacts the first surface of the bag wing during the second press.

6. The battery cell pouch wing bending device according to claim 5, characterized in that, The bending section has a curved portion that is bent at a predetermined curvature to connect the first contact surface to the second contact surface.

7. The battery cell pouch wing bending device according to claim 6, characterized in that, When the bending processing part moves along the first direction while the first contact surface is in contact with the first surface of the bag wing, the first contact surface, the curved portion, and the second contact surface sequentially contact the first surface of the bag wing.

8. The battery cell pouch wing bending device according to claim 5, characterized in that, The bending process is configured such that the second contact surface is inclined relative to the first contact surface in the range of 55 degrees to 85 degrees.

9. The battery cell pouch wing bending device according to claim 5, characterized in that, The pair of heating blades includes a first heating blade that contacts the first surface of the bag wing and a second heating blade that contacts the second surface in the opposite direction to the first surface of the bag wing. The bending processing section is configured such that during the second press, the second contact surface moves toward the second heating blade, and the bag wing portion contacts the second heating blade and the second contact surface respectively.

10. The bag wing bending device for the battery cell according to claim 9, characterized in that, The first heating blade and the second heating blade each include a main body that contacts the bag wing portion and a heat source for providing heat to the main body, and The second heating blade bends along the contact end of the main body that contacts the bag wing toward the bending processing section.

11. The bag wing bending device for the battery cell according to claim 10, characterized in that, The second heating blade is bent such that one side of the contact end is parallel to the second contact surface of the bending process portion.

12. The battery cell pouch wing bending device according to claim 11, characterized in that, After the second pressing of the bending process is completed, the second heating blade is configured to move in a direction away from the bag wing, and one side of the contact end of the second heating blade presses the bag wing three times.

13. The bag wing bending device for the battery cell according to claim 12, characterized in that, After the second pressing of the bending process is completed, the second heating blade moves in the opposite direction to the direction of movement to contact the bag wing.

14. The bag wing bending device for the battery cell according to claim 12, characterized in that, When the second heating blade moves away from the bag wing and presses the bag wing in the opposite direction to the second direction, the bag wing is bent three times.

15. A pouch-type battery cell, characterized in that, include: Electrode assembly; as well as A bag, the bag being used to house the electrode assembly, wherein The bag includes bag wings that are sealed to the outside of the electrode assembly, and The pouch wing is repeatedly bent using the pouch wing bending device of the battery cell according to any one of claims 1 to 14 to include overlapping and non-overlapping portions, and in a state where no external force is applied, the overlapping portion forms a constant angle in the range of 75 degrees to 90 degrees relative to the non-overlapping portion. The portion of the bag wing that contacts a pair of heating blades included in the bag wing bending device forms a seal by applying heat via the pair of heating blades, and the seal is melted by the pair of heating blades.

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