KR20220022848A - The Pouch Type Battery Case And The Pouch Type Secondary Battery - Google Patents

Abstract

A pouch-type battery case according to an embodiment of the present invention for solving the problem has a cup unit for accommodating an electrode assembly formed by stacking electrodes and a separator therein, wherein the cup unit includes a plurality of die edges which connect a plurality of outer walls surrounding the periphery and a degassing unit and at least one of which is formed by being rounded with a radius of curvature of 1 mm or less, and the depth of the cup unit is 6.5 mm or less.

Description

Pouch Type Battery Case And Pouch Type Secondary Battery {The Pouch Type Battery Case And The Pouch Type Secondary Battery}

The present invention relates to a pouch-type battery case and a pouch-type secondary battery, and more particularly, to a pouch-type battery case and pouch-type secondary battery that can increase energy density compared to volume, have a beautiful appearance, and improve marketability it's about

In general, types of secondary batteries include a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, and a lithium ion polymer battery. These secondary batteries are not only for small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDA's, Portable Game Devices, Power Tools and E-bikes, but also for large products requiring high output such as electric and hybrid vehicles and surplus power generation. It is also applied and used in power storage devices that store power or renewable energy and power storage devices for backup.

In order to manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to prepare a positive electrode and a negative electrode, and by laminating them on both sides of a separator, an electrode assembly having a predetermined shape (Electrode Assembly) to form Then, the electrode assembly is accommodated in the battery case and sealed after electrolyte injection.

The secondary battery is classified into a pouch type, a can type, and the like, according to a material of a case for accommodating the electrode assembly. The pouch type accommodates the electrode assembly in a pouch made of a flexible polymer material. And, in the can type, the electrode assembly is accommodated in a case made of a material such as metal or plastic.

A pouch, which is a case of a pouch-type secondary battery, is manufactured by performing press working on a flexible pouch film to form a cup portion. Then, when the cup portion is formed, the electrode assembly is accommodated in the accommodating space of the cup portion and the side is sealed to manufacture a secondary battery.

Among these press working, drawing forming is performed by inserting a pouch film into a forming apparatus such as press equipment, applying pressure to the pouch film with a punch, and stretching the pouch film. However, there is a limit to improving the radius of curvature and clearance of the edge of the cup portion when the cup portion is molded into the pouch film. In addition, the volume ratio of the electrode assembly to the volume of the cup part is small, and there is a limit to reducing the size of the bat ear, so that the energy density compared to the volume of the secondary battery is also reduced. Furthermore, there was a limitation in manufacturing a sharp shape as a whole, and thus the appearance of the secondary battery was not beautiful, so there was a problem in that the merchantability was also lowered.

Japanese Patent Registration No. 6022956

The problem to be solved by the present invention is to provide a pouch-type battery case and a pouch-type secondary battery, which can increase energy density compared to volume, have a beautiful appearance, and can improve marketability.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In the pouch-type battery case according to an embodiment of the present invention for solving the above problems, a cup portion for accommodating an electrode assembly formed by stacking electrodes and a separator therein is formed, and the cup portion includes a plurality of outer walls surrounding the periphery and A plurality of die edges connecting the sides or the degassing portion, at least one of which is rounded with a radius of curvature of 1 mm or less, is included, and the cup portion has a depth of 6.5 mm or less.

In addition, at least one of the die edges may be formed by being rounded with a radius of curvature of 0.7 mm or less.

In addition, the radius of curvature of the die edge may be 1/20 to 1/6 of the depth of the cup portion.

In addition, the cup portion, each connecting the outer wall and the bottom, at least one of a plurality of punch edges formed by rounding with a radius of curvature of 1 mm or less; and a thickness edge connecting the two adjacent outer walls to each other.

In addition, a die edge vertical line passing through the boundary point between the die edge and the die edge side outer wall and perpendicular to the bottom portion, passing through the boundary point between the die edge side punch edge and the die edge side outer wall and perpendicular to the bottom portion The vertical distance between the edge vertical lines may be 0.5 mm or less.

In addition, the thickness edge is connected to two adjacent punch edges to form a corner, and the corner is formed by rounding at least one with a radius of curvature of 2 mm to 5 mm, and the radius of curvature of the thickness edge It may be larger than the radius of curvature.

In addition, the corner, the radius of curvature may change inside.

Also, in the corner, a radius of curvature of a central portion may be greater than a radius of curvature of a peripheral portion.

In addition, at least one of the punch edges may be formed by being rounded with a radius of curvature of 0.7 mm or less.

In addition, the radius of curvature of the punch edge may be 1/20 to 1/6 of the depth of the cup portion.

In addition, a first case and a second case in which the cup portion is formed, respectively; and a bridge formed between the two cup portions, wherein the bridge may have a thickness of 2 mm or less.

In addition, the bridge may have a thickness of 1.4 mm or less.

Also, the bridge may have a thickness of 1/200 to 1/30 of a width of the electrode assembly.

In addition, the bridge may be formed by being rounded with a radius of curvature of 1 mm or less.

In addition, the bridge may be formed by being rounded with a radius of curvature of 0.7 mm or less.

In addition, the thickness of the bridge may be a distance between two bridge vertical lines passing through a boundary point between the bridge and the bridge-side outer wall and perpendicular to the bottom portion.

In addition, the outer wall may have an inclination angle of 90° to 95° from the bottom.

According to an embodiment of the present invention for solving the above problems, a pouch-type secondary battery includes an electrode assembly formed by stacking an electrode and a separator; and a pouch-type battery case having a cup portion for accommodating the electrode assembly therein, wherein the battery case includes: a first case and a second case in which the cup portion is formed in at least one; and a folding part for integrally connecting the first case and the second case, wherein the folding part has a width of 1 mm to 3.2 mm, and a depth of the cup part is 6.5 mm or less.

Also, the electrode assembly may have an area of 15000 mm ² to 100000 mm ² .

In addition, the folding part may have a width of 1 mm to 1.6 mm.

In addition, the folding part may be formed to include a groove recessed inward.

In addition, the battery case may include a pair of protrusions protruding outwardly with the groove interposed therebetween, and a distance between the innermost portion of the groove and the outermost portion of the protrusion may be 0.8 mm or less.

Also, a difference between the width of the cup portion and the width of the electrode assembly may be 2.5 mm or less.

In addition, a difference between the width of the cup portion and the width of the electrode assembly may be 1.7 mm or less.

In addition, the width of the cup portion may be a distance between the upper ends of both side outer walls of the cup portion.

In addition, the cup portion, each connecting a plurality of outer walls and the bottom surrounding the periphery, at least one of the plurality of punch edges formed by rounding with a radius of curvature of 1 mm or less; a plurality of die edges connecting the outer wall and the side or the degassing portion, at least one of which is rounded with a radius of curvature of 1 mm or less; and a thickness edge connecting the two adjacent outer walls to each other.

In addition, a die edge vertical line passing through the boundary point between the die edge and the die edge side outer wall and perpendicular to the bottom portion, passing through the boundary point between the die edge side punch edge and the die edge side outer wall and perpendicular to the bottom portion The vertical distance between the edge vertical lines may be 0.5 mm or less.

In addition, in the electrode assembly, at least one end of the electrode may be positioned at a vertical distance of 0.75 mm or less from the vertical edge line.

Also, in the electrode assembly, at least one end of the electrode may be positioned at a vertical distance of 0.5 mm or less from the vertical edge line.

In addition, in the separator, a peripheral portion protruding outward than the electrode may be folded in a direction opposite to the bottom portion with respect to one end of the electrode.

In addition, in the electrode assembly, the electrode and the separator are each formed in plurality, and the separator accommodated in the cup portion of the first case, the peripheral portion is folded toward the second case, and the second case The separation membrane accommodated in the cup portion of the periphery may be folded toward the first case.

In addition, the peripheral portion of the at least one separator may be folded while aligned with the peripheral portion of the adjacent separator.

In addition, at least one of the punch edges may be formed by being rounded with a radius of curvature of 0.7 mm or less.

In addition, the radius of curvature of the punch edge may be 1/20 to 1/6 of the depth of the cup portion.

In addition, at least one of the die edges may be formed by being rounded with a radius of curvature of 0.7 mm or less.

In addition, the radius of curvature of the die edge may be 1/20 to 1/6 of the depth of the cup portion.

In addition, the outer wall may have an inclination angle of 90° to 95° from the bottom portion.

In addition, the thickness edge is connected to two adjacent punch edges to form a corner, and the corner is formed by rounding at least one with a radius of curvature of 2 mm to 5 mm, and the radius of curvature of the thickness edge It may be larger than the radius of curvature.

In addition, the corner, the radius of curvature may change inside.

Also, in the corner, a radius of curvature of a central portion may be greater than a radius of curvature of a peripheral portion.

In addition, at both ends of the folding part, it may further include a bat ear which is formed to protrude 1.5 mm or less in length to the outside.

In addition, an angle between the folding part and the inner edge of the bat ear may be greater than 151 degrees.

Other specific details of the invention are included in the detailed description and drawings.

According to the embodiments of the present invention, there are at least the following effects.

The radius of curvature and clearance of the edge of the cup part of the pouch-type battery case and the pouch-type secondary battery can be made smaller, and the thickness of the bridge can be made thinner, so that the width of the folding part can be reduced, and the volume of the electrode assembly can be increased , the size of the bat ear can be reduced, and the edge high phenomenon can be prevented from occurring, so that the energy density to volume ratio can be increased.

In addition, since the pouch-type battery case and the pouch-type secondary battery may be manufactured in a sharp shape as a whole, the appearance of the secondary battery may be beautiful and marketability may be improved.

The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is an assembly view of a secondary battery 1 according to an embodiment of the present invention.
2 is a cross-sectional view of a pouch film 135 according to an embodiment of the present invention.
3 is a schematic diagram of a forming apparatus 2 according to an embodiment of the present invention.
4 is an enlarged schematic view of the conventional cup portion 333 and the bridge 336.
5 is an enlarged schematic view of the cup portion 133 and the bridge 136 according to an embodiment of the present invention.
6 is an enlarged schematic view of the cup part 133 and the degassing part 137 according to an embodiment of the present invention.
7 is a schematic top view showing a state in which the electrode assembly 10 is accommodated in the cup part 133 according to an embodiment of the present invention.
8 is a schematic diagram illustrating a conventional corner 364 .
9 is a schematic diagram illustrating a corner 164 according to an embodiment of the present invention.
10 is a schematic view showing a state of folding the battery case 13 according to an embodiment of the present invention.
11 is a schematic view showing a folded state of the battery case 13 according to an embodiment of the present invention.
12 is an enlarged view of the groove 1391 formed in the battery case 13 according to an embodiment of the present invention.
13 is an enlarged schematic view of the cup portion 133 and the die edge 1621 according to another embodiment of the present invention.
14 is a schematic view showing a state of folding the battery case 13a according to another embodiment of the present invention.
15 is a schematic view showing a folded state of the battery case 13a according to another embodiment of the present invention.
16 is an enlarged view of the groove 1391a formed in the battery case 13 according to another embodiment of the present invention.
17 is a schematic diagram showing the state before cutting the degassing unit 337 of the conventional battery case 33 from above.
18 is a schematic diagram showing a state before cutting the degassing unit 137 of the battery case 13 according to an embodiment of the present invention from above.
19 is a block diagram of an inspection apparatus 4 according to an embodiment of the present invention.
20 is a schematic diagram illustrating a state in which the manufacture of the secondary battery 1 is completed by cutting the degassing unit 137 of the battery case 13 according to an embodiment of the present invention.
21 is a schematic view showing a state in which the conventional side 334 is folded from the side.
22 is a schematic view showing a state in which the conventional side 334 is folded from the top.
23 is a schematic view showing the folded side 134 according to an embodiment of the present invention from the side.
24 is a schematic diagram of a battery module 5 according to an embodiment of the present invention.
25 is a front enlarged view showing a state in which the conventional secondary battery 3 is accommodated in the housing 51 of the battery module 5 .
26 is an enlarged side view showing a state in which the conventional secondary battery 3 is accommodated in the housing 51 of the battery module 5 .
27 is an enlarged front view showing a state in which the secondary battery 1 is accommodated in the housing 51 of the battery module 5 according to an embodiment of the present invention.
28 is an enlarged side view showing a state in which the secondary battery 1 is accommodated in the housing 51 of the battery module 5 according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components in addition to the stated components.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an assembly view of a secondary battery 1 according to an embodiment of the present invention.

According to an embodiment of the present invention, the radius of curvature and the clearance of the edge of the cup part of the pouch-type battery case and the pouch-type secondary battery can be made smaller, and the thickness of the bridge can be made thinner, so that the width of the folding part can also be reduced. In addition, since the volume of the electrode assembly may be increased, the size of the bat ear may be reduced, and the edge high phenomenon may be prevented from occurring, the energy density relative to the volume may be increased. In addition, since the pouch-type battery case and the pouch-type secondary battery may be manufactured in a sharp shape as a whole, the appearance of the secondary battery may be beautiful and marketability may be improved.

To this end, in the pouch-type battery case according to an embodiment of the present invention, a cup portion for accommodating an electrode assembly formed by stacking electrodes and a separator is formed therein, and the cup portion includes a plurality of outer walls and bottom portions surrounding the periphery. A plurality of punch edges connected to each other and formed by rounding at least one with a radius of curvature of 1 mm or less; a plurality of die edges connecting the outer wall and the side or the degassing portion, at least one of which is rounded with a radius of curvature of 1 mm or less; and a thickness edge connecting two adjacent outer walls to each other, a die edge vertical line passing through a boundary point between the die edge and the die edge side outer wall and perpendicular to the bottom portion, the die edge side punch edge and the die The vertical distance between the edge vertical line passing through the edge-side outer wall and perpendicular to the bottom is 0.5 mm or less, and the thickness edge is connected to the two adjacent punch edges to form a corner, the corner is At least one is rounded with a radius of curvature of 2 mm to 5 mm, the radius of curvature is greater than the radius of curvature of the thickness edge, and the depth of the cup portion is 6.5 mm or less.

And the pouch-type secondary battery according to an embodiment of the present invention includes an electrode assembly formed by stacking an electrode and a separator; and a pouch-type battery case having a cup portion for accommodating the electrode assembly therein, wherein the battery case includes: a first case and a second case in which the cup portion is formed in at least one; a folding unit integrally connecting the first case and the second case; and a bat ear protruding outward from a portion of both ends of the folding part, wherein the cup part connects a plurality of outer walls surrounding the periphery and a bottom part, respectively, and at least one is rounded with a radius of curvature of 1 mm or less. a plurality of punch edges; a plurality of die edges connecting the outer wall and the side or the degassing portion, at least one of which is rounded with a radius of curvature of 1 mm or less; and a thickness edge connecting two adjacent outer walls to each other, a die edge vertical line passing through a boundary point between the die edge and the die edge side outer wall and perpendicular to the bottom, the die edge side punch edge and the die The vertical distance between the edge vertical line passing through the edge-side outer wall and perpendicular to the bottom is 0.5 mm or less, and the thickness edge is connected to the two adjacent punch edges to form a corner, the corner is at least one is rounded and formed with a radius of curvature of 2 mm to 5 mm, the radius of curvature is greater than the radius of curvature of the thickness edge, the folding part has a width of 1 mm to 3.2 mm, and the bat ear has a length of 1 mm or less, a difference between a width of the cup part and a width of the electrode assembly is 2.5 mm or less, and a depth of the cup part is 6.5 mm or less.

The electrode assembly 10 is formed by alternately stacking an electrode 101 (shown in FIG. 5 ) and a separator 102 (shown in FIG. 5 ). First, a slurry in which an electrode active material, a binder, and a plasticizer are mixed is applied to a positive electrode current collector and a negative electrode current collector to prepare electrodes 101 such as a positive electrode and a negative electrode. Then, separators 102 are stacked between the electrodes 101 to form the electrode assembly 10 , the electrode assembly 10 is inserted into the battery case 13 , and the electrolyte is injected and then sealed.

The electrode assembly (Electrode Assembly, 10) may have an area of 15000 mm ² to 100000 mm ² multiplied by an overall length and a full width. In particular, the total width of the electrode assembly 10 may be 60 mm or more. Also, the electrode assembly 10 may have a thickness of 6 mm or more in the stacking direction. Therefore, the electrode assembly 10 according to an embodiment of the present invention can provide a large battery capacity compared to a general small-sized battery.

Specifically, the electrode assembly 10 includes two types of electrodes 101 , a positive electrode and a negative electrode, and a separator 102 interposed between the electrodes 101 to insulate the electrodes 101 from each other. The electrode assembly 10 may be of a stack type, a jelly roll type, a stack-and-fold type, or the like. The two types of electrodes 101, that is, the positive electrode and the negative electrode, have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh including aluminum and copper, respectively. The active material slurry may be formed by stirring a granular active material, a conductive material, and the like in a state in which a solvent is added thereto. The solvent is removed in a subsequent process.

As shown in FIG. 1 , the electrode assembly 10 includes an electrode tab 11 . The electrode tab 11 is respectively connected to the positive electrode and the negative electrode of the electrode assembly 10 , and protrudes from the electrode assembly 10 , and serves as a path through which electrons can move between the inside and the outside of the electrode assembly 10 . . The electrode current collector of the electrode assembly 10 includes a portion to which the electrode active material is applied and a distal portion to which the electrode active material is not applied, that is, an uncoated portion. In addition, the electrode tab 11 may be formed by cutting the uncoated area or may be formed by connecting a separate conductive member to the uncoated area by ultrasonic welding or the like. As shown in FIG. 1 , the electrode tabs 11 may protrude in different directions of the electrode assembly 10 , but are not limited thereto and may protrude in various directions, such as protruding side by side in the same direction from one side. may be

An electrode lead 12 for supplying electricity to the outside of the secondary battery 1 is connected to the electrode tab 11 of the electrode assembly 10 by spot welding or the like. A part of the electrode lead 12 is surrounded by the insulating portion 14 . The insulating part 14 is located limitedly on the side 134 to which the first case 131 and the second case 132 of the battery case 13 are thermally fused, and the electrode lead 12 is connected to the battery case 13 . adhere to In addition, electricity generated from the electrode assembly 10 is prevented from flowing to the battery case 13 through the electrode lead 12 , and the sealing of the battery case 13 is maintained. Accordingly, the insulating portion 14 is made of a non-conductive material that does not conduct electricity well. In general, as the insulating part 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is often used. there is.

One end of the electrode lead 12 is connected to the electrode tab 11 , and the other end protrudes to the outside of the battery case 13 , respectively. That is, the electrode lead 12 has one end connected to the positive electrode tab 111 , and one end connected to the positive electrode lead 121 and the negative electrode tab 112 extending in the protruding direction of the positive electrode tab 111 , and the negative electrode tab 112 includes a negative lead 122 extending in the protruding direction. On the other hand, as shown in FIG. 1 , the positive lead 121 and the negative lead 122 both have the other end protruding to the outside of the battery case 13 . Accordingly, electricity generated inside the electrode assembly 10 may be supplied to the outside. Also, since the positive electrode tab 111 and the negative electrode tab 112 are formed to protrude in various directions, respectively, the positive electrode lead 121 and the negative electrode lead 122 may also extend in various directions.

The material of the positive lead 121 and the negative lead 122 may be different from each other. That is, the positive electrode lead 121 may be made of the same aluminum (Al) material as the positive electrode current collector, and the negative electrode lead 122 may be made of the same copper (Cu) material or nickel (Ni) coated copper material as the negative electrode current collector. And a portion of the electrode lead 12 protruding to the outside of the battery case 13 becomes a terminal part, and is electrically connected to the external terminal.

The battery case 13 is a pouch manufactured by molding a pouch film 135 having a flexible material that accommodates the electrode assembly 10 therein. Hereinafter, the battery case 13 will be described as a pouch. When the pouch film 135 having flexibility is drawn and molded using a punch 22 (shown in FIG. 6 ), the cup portion 133 including the pocket-shaped accommodation space 1331 is partially stretched. By being formed, the battery case 13 is manufactured.

The battery case 13 accommodates and seals the electrode assembly 10 so that a portion of the electrode lead 12 is exposed. As shown in FIG. 1 , the battery case 13 includes a first case 131 and a second case 132 . A cup portion 133 is formed in the first case 131 to provide an accommodating space 1331 accommodating the electrode assembly 10 , and the second case 132 includes the electrode assembly 10 in the battery case ( 13), the accommodation space 1331 is covered from above so as not to be separated from the outside. The first case 131 and the second case 132 may be manufactured by connecting one side to each other as shown in FIG. 1 , but is not limited thereto and may be manufactured in various ways, such as being separated from each other and manufactured separately.

When the cup portion 133 is formed in the pouch film 135 , only one cup portion 133 may be formed in one pouch film 135 , but the present invention is not limited thereto and two cup portions are formed in one pouch film 135 . It is also possible to draw molding 133 adjacent to each other. Then, as shown in FIG. 1 , a cup portion 133 is formed in the first case 131 and the second case 132 , respectively. At this time, each of the cup portions 133 formed in the first case 131 and the second case 132 may have the same depth D, but is not limited thereto and may have different depths D. there is.

In the case of one embodiment of the present invention, the depth (D) of the cup portion 133 may be 3mm or more and 6.5mm or less. Accordingly, the cup part 133 according to an embodiment of the present invention can accommodate the electrode assembly 10 having a larger electrode capacity compared to a general small-sized battery.

After the electrode assembly 10 is accommodated in the accommodating space 1331 provided in the cup portion 133 of the first case 131 , the two cup portions 133 in the battery case 13 so that the two cup portions 133 face each other. The battery case 13 may be folded around the bridge 136 formed between the . Then, the cup part 133 of the second case 132 also accommodates the electrode assembly 10 from above. Accordingly, since the two cup portions 133 accommodate one electrode assembly 10 , the electrode assembly 10 having a thickness greater than that of one cup portion 133 may be accommodated. In addition, since the first case 131 and the second case 132 are integrally connected to each other by folding the battery case 13, the number of sides 134 to be sealed when a sealing process is performed later can be reduced. there is. Accordingly, it is possible to improve the process speed and reduce the number of sealing processes.

On the other hand, the battery case 13 is formed on the side of the cup portion 133 and the cup portion 133 having an accommodation space 1331 for accommodating the electrode assembly 10, and the cup portion 133 through the degassing hole H. It may include a degassing unit 137 for discharging the gas generated inside the. When the electrode assembly 10 is accommodated in the cup part 133 of the battery case 13 and an electrolyte is injected and an activation process is performed, gas is generated inside the battery case 13 and the gas is discharged to the outside. To perform a degassing process. A detailed description of the degassing unit 137 will be described later.

When the electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 and the insulating portion 14 is formed on a portion of the electrode lead 12 , the cup portion 133 of the first case 131 is The electrode assembly 10 is accommodated in the provided accommodation space 1331 , and the second case 132 covers the space from the top. Then, the electrolyte is injected therein, and the side 134 extending outwardly of the cup part 133 of the first case 131 and the second case 132 is sealed. The electrolyte is for moving lithium ions generated by the electrochemical reaction of the electrode 101 during charging and discharging of the secondary battery 1, and is a non-aqueous organic electrolyte or polymer electrolyte that is a mixture of lithium salt and high-purity organic solvents. It may include a polymer using Furthermore, the electrolyte may include a sulfide-based, oxide-based, or polymer-based solid electrolyte, and the solid electrolyte may have flexibility to be easily deformed by an external force. Through this method, the pouch-type secondary battery 1 may be manufactured.

2 is a cross-sectional view of a pouch film 135 according to an embodiment of the present invention.

The pouch, which is the battery case 13 of the pouch-type secondary battery 1 according to an embodiment of the present invention, is manufactured by drawing and molding the pouch film 135 . That is, the pouch film 135 is stretched with a punch 22 or the like to form the cup portion 133 . According to one embodiment of the present invention, such a pouch film 135 is, as shown in FIG. 2, a sealant layer (Sealant Layer, 1351), a moisture barrier layer (Moisture Barrier Layer, 1352), a surface protection layer (Surface Protection) Layer 1353), and may further include a drawing assistance layer (Drawing Assistance Layer, 1354) if necessary.

The sealant layer 1351 is made of the first polymer and is formed on the innermost layer to directly contact the electrode assembly 10 . Here, the innermost layer refers to a layer positioned at the end when the electrode assembly 10 is positioned with respect to the moisture barrier layer 1352 . When the pouch film 135 of the stacked structure as described above is drawn and molded using a punch 22 or the like, the battery case 13 is partially elongated and a cup portion including a pocket-shaped accommodation space 1331 . It is produced while forming (133). Then, when the electrode assembly 10 is accommodated in the receiving space 1331, the electrolyte is injected. After that, when the first case 131 and the second case 132 are brought into contact with each other to face each other and thermocompression is performed on the side 134 , the sealant layers 1351 are adhered to each other, thereby sealing the pouch. In this case, the sealant layer 1351 must have insulation because it directly contacts the electrode assembly 10 , and must have corrosion resistance because it also comes in contact with the electrolyte. In addition, since the inside must be completely sealed to block material movement between the inside and the outside, it must have high sealing properties. That is, the side 134 to which the sealant layers 1351 are bonded should have excellent thermal bonding strength. In general, the first polymer for manufacturing the sealant layer 1351 is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, It may be made of one or more materials selected from the group consisting of nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) is mainly used. Polypropylene (PP) has excellent mechanical properties such as tensile strength, rigidity, surface hardness, abrasion resistance, heat resistance, and chemical properties such as corrosion resistance, and is mainly used for manufacturing the sealant layer 1351 . Furthermore, it may be composed of Cated Polypropylene or Acid Modified Polypropylene or polypropylene-butylene-ethylene terpolymer. Here, the acid-treated polypropylene may be MAH PP (maleic anhydride polypropylene). In addition, the sealant layer 1351 may have a single-layer structure made of any one material or a composite film structure in which two or more materials are each layered.

The moisture barrier layer 1352 is laminated between the surface protective layer 1353 and the sealant layer 1351 to secure the mechanical strength of the pouch, block the ingress of gas or moisture from the outside of the secondary battery 1, and electrolyte to prevent leakage of The moisture barrier layer 1352 may be made of an aluminum alloy thin film. The aluminum alloy thin film may secure a predetermined level or more of mechanical strength, while having a light weight, and supplementing the electrochemical properties of the electrode assembly 10 and the electrolyte and securing heat dissipation.

More specifically, the aluminum alloy thin film according to an embodiment of the present invention may have a grain size of 10 to 13 μm, preferably 10.5 to 12.5 μm, and more preferably 11 to 12 μm. When the grain size of the aluminum alloy thin film satisfies the above range, it is possible to increase the forming depth without generating pinholes or cracks during cup forming.

Such an aluminum alloy thin film contains metal elements other than aluminum, for example, iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg) and zinc (Zn). One or two or more selected from the group consisting of may be included.

The surface protective layer 1353 is made of the second polymer and is formed on the outermost layer to protect the secondary battery 1 from friction and collision with the outside while electrically insulating the electrode assembly 10 from the outside. Here, the outermost layer refers to a layer that is positioned last when facing in a direction opposite to a direction in which the electrode assembly 10 is positioned with respect to the moisture barrier layer 1352 . The second polymer for manufacturing the surface protective layer 1353 is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon. , polyester, polyparaphenylenebenzobisoxazole, polyarylate, may be at least one material selected from the group consisting of Teflon and glass fiber. In particular, a polymer such as polyethylene terephthalate (PET) having mainly abrasion resistance and heat resistance is preferably used. In addition, the surface protection layer 1353 may have a single-layer structure made of any one material, or a composite film structure in which two or more materials are each layered.

On the other hand, PET is inexpensive, has excellent durability, and has excellent electrical insulation, but has weak adhesion to aluminum, which is often used as the moisture barrier layer 1352 , and has different behavior when stretched by applying a stress. Accordingly, when the surface protective layer 1353 and the moisture barrier layer 1352 are directly bonded, the surface protective layer 1353 and the moisture barrier layer 1352 may be peeled off during drawing molding. As a result, the moisture barrier layer 1352 is not stretched uniformly, which may cause a problem in that moldability is deteriorated.

According to an embodiment of the present invention, the battery case 13 may further include an auxiliary stretching layer 1354 made of a third polymer and laminated between the surface protection layer 1353 and the moisture barrier layer 1352 . there is. The stretching auxiliary layer 1354 is laminated between the surface protective layer 1353 and the moisture barrier layer 1352 to prevent the surface protective layer 1353 and the moisture barrier layer 1352 from peeling off when stretched. The third polymer for manufacturing the stretching auxiliary layer 1354 is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon. , polyester, polyparaphenylenebenzobisoxazole, polyarylate, may be at least one material selected from the group consisting of Teflon and glass fiber. In particular, since the nylon resin easily adheres to polyethylene terephthalate (PET) of the surface protective layer 1353 and has a similar behavior to the aluminum alloy of the moisture barrier layer 1352 when stretched, the third polymer It is preferable that mainly nylon (Nylon) resin is used as the furnace. In addition, the stretching auxiliary layer 1354 may have a single film structure made of any one material, or a composite film structure in which two or more materials are each formed in layers.

Meanwhile, the pouch film 135 according to the present invention may have a total thickness of 160 μm to 200 μm, preferably 180 μm to 200 μm. When the thickness of the pouch film 135 satisfies the above range, it is possible to increase the molding depth while minimizing the reduction of the battery accommodating space and the deterioration of sealing durability due to the increase in the pouch thickness.

3 is a schematic diagram of a forming apparatus 2 according to an embodiment of the present invention.

The molding apparatus 2 for molding the pouch film 135 according to an embodiment of the present invention includes a die 21 on which the pouch film 135 is seated on an upper surface, and is disposed above the die 21 and descends. and a punch 22 for forming the pouch film 135 . And the die 21 includes a forming portion 211 recessed inwardly from the upper surface, and the punch 22 forms the cup portion 133 by inserting the pouch film 135 into the forming portion 211 and drawing-molding. do.

According to an embodiment of the present invention, when molding the pouch film 135 using the molding device 2 , as shown in FIG. 3 , the die 21 has two molding parts 211 adjacent to each other. A dog is formed, and a partition wall 212 may be formed between the two forming parts 211 . When the pouch film 135 is draw-molded while the punch 22 is inserted into both molding units 211 , one in each of the first case 131 and the second case 132 is formed corresponding to the two molding units 211 . , a total of two cup portions 133 are formed, and a bridge 136 may also be formed between the two cup portions 133 to correspond to the partition wall 212 .

The bridge 136 may serve as a reference when the battery case 13 is later folded. When the manufacture of the secondary battery 1 is completed, the bridge 136 may form a folding part 139 (shown in FIG. 11 ) at one side of the secondary battery 1 . Since the folding part 139 integrally connects the first case 131 and the second case 132 to each other, the number of sides 134 to be sealed may be reduced when a sealing process is performed later. Accordingly, it is possible to improve the process speed and reduce the number of sealing processes. At this time, as the width of the folding part 139 decreases, the space 17 (shown in FIG. 5 ) between the outer wall 138 (shown in FIG. 5 ) of the cup part 133 and the electrode assembly 10 also decreases, Since the overall volume of the secondary battery 1 is reduced, the energy density relative to the volume may be increased.

The width of the folding part 139 is proportional to the thickness (t, shown in FIG. 5) of the bridge 136, and since the bridge 136 is formed corresponding to the partition wall 212, the thickness of the bridge 136 ( t) is proportional to the thickness of the partition wall 212 . Therefore, when the pouch film 135 is formed, it is preferable to minimize the thickness t of the bridge 136 , and for this purpose, it is also preferable to minimize the thickness of the partition wall 212 . However, if the barrier rib 212 is formed to have an excessively high height in a thin state, the barrier rib 212 may be damaged in the process of drawing forming. In particular, in the prior art, there was a bottom in the die, but in this case, when the punch 22 molds the pouch film 135 , the gas present in the space between the pouch film 135 and the molding unit 211 cannot be discharged. There was a problem. Therefore, recently, by removing the bottom of this die, the gas present in the space between the pouch film 135 and the molding unit 211 can be easily discharged, but the height of the partition wall 212 is excessively high. There was a problem. Accordingly, according to an embodiment of the present invention, as shown in FIG. 3 , a reinforcement portion 2121 thicker than the thickness of the partition wall 212 may be formed under the partition wall 212 . The reinforcing part 2121 may be formed below the depth D of the cup part 133 to be formed in the battery case 13 , and may be formed at a position where the partition wall 212 is not damaged. The exact position of the reinforcing part 2121 may be experimentally determined according to the thickness of the partition wall 212 , the material of the partition wall 212 , the pressure of the punch 22 , the depth D of the cup part 133 to be formed, and the like.

4 is an enlarged schematic view of the conventional cup portion 333 and the bridge 336.

Conventionally, even when manufacturing a battery case and a secondary battery, there is a limit in manufacturing the overall sharp shape.

Specifically, there is a limit in reducing the radius of curvature of the edge 36 of the cup portion 333 in the prior art.

The edge 36 of the cup portion 333 corresponds to the edge 221 (shown in FIG. 3) of the punch 22 and is formed and formed as a punch edge 361. The edge 213 of the die 21 is shown in FIG. 3 ) and a die edge 362 (shown in FIG. 8 ) formed corresponding to the .

The punch edge 361 connects the plurality of outer walls 338 surrounding the periphery of the cup portion 333 and the bottom portion 3332 , respectively. However, if the edge 221 of the punch 22 is not rounded, the edge 221 of the punch 22 becomes sharp, so when the pouch film 135 is formed, the punch edge 361 of the cup part 333 is There was a problem in that the stress was concentrated on the surface and cracks easily occurred. In addition, the die edge 362 connects the plurality of outer walls 338 and the side 134 or the degassing unit 137 , respectively. However, if the edge 213 of the die 21 is not rounded, the edge of the die 21 becomes sharp. When the pouch film 135 is formed, stress is also concentrated on the die edge 362 of the cup portion 333 . There was a problem that cracks easily occur. Here, being rounded means forming a curved surface to have a curvature, and the curved surface may have only a constant curvature, but is not limited thereto and may have a non-constant curvature. In the present specification, the punch edge 161, the die edge 162, the bridge 136, etc. are rounded and formed with a specific curvature, as well as having only the specific curvature as a whole, but also having the specific curvature only at least in part means to include

In order to solve the above problem, as shown in FIG. 4 , rounding is performed on the edge 221 of the punch 22 and the edge 213 of the die 21 to provide a punch edge 361 of the cup part 333 . and the die edge 362 are rounded and formed. Thereby, the stress concentrated on the punch edge 361 and the die edge 362 of the cup part 333 was able to be dispersed to some extent.

However, even if the punch edge 361 and the die edge 362 of the cup portion 333 are rounded and formed, the radius of curvature R2' of the punch edge 361 and the die compared to the depth D' of the cup portion 333 If the radius of curvature of the edge 362 is formed to be small, cracks occurred in the punch edge 361 and the die edge 362 of the cup portion 333 . For example, in the related art, as a standard for molding one cup portion 333, the depth D' is approximately 7 mm or more, and the depth D' is approximately 7 mm or more based on the case where two cup portions 333 are formed. When molded to 6.5 mm or more, cracks may occur in the pouch film 135 when the radius of curvature R2' of the punch edge 361 of the cup part 333 and the radius of curvature of the die edge 362 are formed to be 2 mm or less. could

In addition, when the two cup portions 133 are formed, the partition wall 212 must exist in the die 21 in order to form the bridge 136 . However, in the prior art, when the depth D' of the cup portion 333 is formed to be deep (eg, 6.5 mm or more), there is a limit in forming the thickness of the bridge 336 thin. That is, if the barrier rib 212 is also formed to have a predetermined thickness or less in order to form the bridge 336 to a predetermined thickness or less, cracks may occur in the bridge 336 because the barrier rib 212 is sharply formed.

In order to solve this problem, as shown in FIG. 4 , the bridge 336 is formed by rounding the partition wall 212 by rounding. As a result, the stress concentrating on the bridge 336 was able to be dispersed to some extent. In particular, when the radius of curvature R1 ′ of the bridge 336 is constant, the radius of curvature R1 ′ corresponds to half of the thickness t′ of the bridge 336 . For example, when the radius of curvature R1' of the bridge 336 is formed to be close to about 1 mm, the thickness t' of the bridge 336 is formed to be close to about 2 mm.

However, even if the bridge 336 is rounded and formed, when the depth D' of the cup part 333 is formed to be deep, the bridge 336 has a crack when the thickness t' of the bridge 336 is small. For example, if the depth (D') of the cup part 333 is formed to be approximately 6.5 mm or more, the radius of curvature (R1') of the bridge 336 is 1 mm or less, that is, the thickness (t') of the bridge 336 There was a problem in that cracks occur in the bridge 336 when forming to 2 mm or less.

Furthermore, since the size of the clearance CL' is also quite large, there is a limit to forming the outer wall 338 of the cup part 333 to be nearly vertical. The clearance CL refers to a vertical distance between the inner wall of the forming portion 211 of the die 21 and the outer wall of the punch 22 . Actually, there is a difference in size between the forming part 211 of the die 21 and the punch 22 as fine as the clearance CL. If the clearance CL is excessively small, the distance between the inner wall of the forming portion 211 and the outer wall of the punch 22 is excessively small. Then, the pouch film 135 may not be inserted into the molding unit 211 , or the pouch film 135 may be damaged due to large friction. Conversely, if the clearance CL is excessively large, the inclination angle of the outer wall 338 of the cup portion 333 increases, and the space 37 between the outer wall 338 of the cup portion 333 and the electrode assembly 10 increases. there is Therefore, when the pouch film 135 is molded, a clearance CL of an appropriate size must be set.

The bridge 336 is formed to correspond to the partition wall 212 of the die 21 , and the punch edge 361 is formed to correspond to the edge 221 of the punch 22 . Accordingly, the clearance CL ′, which is the vertical distance between the inner wall of the forming portion 211 of the die 21 and the outer wall of the punch 22 , is in the battery case 33 , between the bridge 336 and the punch edge 361 . It can appear as a vertical distance.

Specifically, as shown in FIG. 4 , the bridge vertical line V1 ′ and the edge vertical line V2 ′ are virtually illustrated. The bridge vertical line V1 ′ is an imaginary vertical line passing through the boundary point P1 ′ between the bridge 336 and the bridge 336 side outer wall 338 and perpendicular to the bottom part 3332 . And, the edge vertical line V2' passes through the boundary point P2' of the bridge 336 side punch edge 361 and the bridge 336 side outer wall 338 and is a virtual vertical line perpendicular to the bottom part 3332. . The bridge vertical line V1 ′ corresponds to the inner wall of the forming part 211 of the die 21 , in particular, the inner wall of the partition 212 , and the edge vertical line V2 ′ corresponds to the outer wall of the punch 22 . Accordingly, the vertical distance between the vertical bridge line V1 ′ and the edge vertical line V2 ′ is the clearance CL′ appearing in the battery case 33 .

However, conventionally, if the depth D' of the cup portion 333 is formed to be deep (eg, 6.5 mm or more), cracks easily occur in the pouch film 135 when the clearance CL is reduced to 0.5 mm or less. As described above, conventionally, when the depth D' of the cup part 333 is formed to be deep (eg, 6.5 mm or more), it is difficult to form the clearance CL' smaller. Since there is a limit, the outer wall 338 of the cup portion 333 is formed to have an inclination angle greater than 95° from the bottom portion 3332 . That is, there was a limit in forming the outer wall 338 of the cup portion 333 to be close to the vertical with an inclination angle of 95° or less.

On the other hand, since there is a limit in improving the radius of curvature R2 ′ of the edge of the cup portion 333 , there is also a problem in that the volume of the electrode assembly 10 accommodated in the cup portion 333 is reduced. Specifically, as shown in FIG. 4 , in the related art, since the radius of curvature R2 ′ of the punch edge 361 of the cup portion 333 is large, the electrode assembly 10 is attached to the outer wall 338 of the cup portion 333 . When positioned too close, there is a problem in that the electrode 101 of the electrode assembly 10 is damaged by the punch edge 361 of the cup portion 333 . That is, one end of the electrode 101 including the metal is positioned on the punch edge 361 of the cup portion 333 , and one end of the electrode 101 corresponds to the punch edge 361 of the cup portion 333 and is deformed. There was a problem with breakage.

In order to solve this problem, in the related art, when the electrode assembly 10 is accommodated in the cup part 333 , the electrode assembly 10 is accommodated at a certain distance from the outer wall 338 of the cup part 333 . First, a vertical distance g' from the edge vertical line V2' is 0.75 mm, particularly 0.5 mm, and a reference vertical line V3' perpendicular to the bottom part 3332 is shown virtually, and then shown in FIG. As shown, the electrode assembly 10 was accommodated so that one end of the electrode 101 was positioned outside the reference vertical line V3'. Accordingly, since the electrode 101 is spaced apart from the outer wall 338 of the cup portion 333 to some extent, it is possible to prevent the electrode 101 from being damaged. However, in this case, since the space 37 between the outer wall 338 of the cup part 333 and the electrode assembly 10 increases, the volume ratio of the electrode assembly 10 to the volume of the cup part 333 decreases, so that the secondary battery There was a problem in that the energy density compared to the volume of (3) was lowered. In addition, since the volume of unnecessary space inside the cup part 333 increases, there is a problem in that the electrode assembly 10 moves inside the cup part 333 before sealing the side.

In addition, in the electrode assembly 10 , the electrode 101 has a high rigidity that is not easily deformed by an external force, whereas the separator 102 has a high flexibility that is easily deformed by an external force. However, when the neighboring electrodes 101 are in direct contact with each other, a short occurs. In order to prevent this, the separator 102 is formed to be larger than the electrode 101 . Accordingly, when the electrode assembly 10 is formed, the peripheral portion 1021 in which the separator 102 protrudes outward than the electrode 101 is formed together. However, in the prior art, since the electrode assembly 10 was received at a certain distance from the outer wall 338 of the cup portion 333, the peripheral portions 1021 of the separator 102 were all disorderly crumpled or folded to form the electrode 101. The possibility of a short circuit was high as it was exposed to the outside.

As such, in the prior art, when the depth (D') of the cup part 333 is formed to be deep (eg, 6.5 mm or more), the thickness (t') of the bridge 336 and the edge 361 of the cup part 333 are formed. There was a limit to improving the radius of curvature R2' and the clearance CL'. In addition, since the volume ratio of the electrode assembly 10 to the volume of the cup part 333 is small, and an unnecessary volume in the secondary battery 3 is also large, the energy density to volume ratio is also reduced. Furthermore, since the outer wall 338 of the cup portion 333 is not formed close to vertical and the radius of curvature R2 of the edge 361 of the cup portion 133 is also large, there is a limitation in manufacturing a sharp shape as a whole. The appearance of (3) was not beautiful, and there was a problem in that the marketability was also lowered.

5 is an enlarged schematic view of the cup part 133 and the bridge 136 according to an embodiment of the present invention, and FIG. 6 is an enlarged view of the cup part 133 and the degassing part 137 according to an embodiment of the present invention. It is a schematic diagram.

According to an embodiment of the present invention, the depth (D) of the cup portion 133 is molded to be 6.5 mm or less, and at the same time, the thickness (t) of the bridge 136 is made thinner, the edge 16 of the cup portion 133 By making the radius of curvature R2 and the clearance CL smaller, the volume of the electrode assembly 10 may be increased. Accordingly, since an unnecessary volume in the secondary battery 1 is also reduced, the energy density relative to the volume may be increased. In addition, since the pouch-type battery case 13 and the pouch-type secondary battery 1 may be manufactured in a sharp shape as a whole, the appearance of the secondary battery 1 may be excellent and marketability may be improved.

To this end, in the pouch-type battery case 13 according to an embodiment of the present invention, a cup portion 133 for accommodating the electrode assembly 10 formed by stacking the electrode 101 and the separator 102 therein is formed. However, the cup portion 133 includes a plurality of punch edges 161 for connecting the plurality of outer walls 138 and the bottom portion 1332 surrounding each other; a plurality of die edges 162 connecting the outer wall 138 and the side 134 or the degassing portion 137; and a thickness edge 163 connecting the two adjacent outer walls 138 to each other.

At least one of the punch edges 161 and at least one of the die edges 162 may be rounded and formed with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . If the radius of curvature R2 of each of the edges 161 and 162 is less than 1/20 of the depth D of the cup portion 133, the stress may be excessively concentrated on each edge 161 and 162 and cracks may occur. And, when the radius of curvature R2 of each edge 161 and 162 is greater than 1/6 of the depth D of the cup portion 133, the cup portion 133 is not sharply formed, and thus energy density may be reduced.

Specifically, at least one of the punch edges 161 may be formed by being rounded with a radius of curvature R2 that is 1 mm or less, and the die edge 162 has at least one radius of curvature R2 that is 1 mm or less. It may be formed by rounding.

A die edge vertical line V4 passing through the boundary points P1 and P3 of the die edge 162 and the outer wall 138 on the die edge 162 side and perpendicular to the bottom 1332, and the die edge 162 ) passing through the boundary points P2 and P4 of the side punch edge 161 and the die edge 162 side outer wall 138 and the vertical distance CL between the bottom portion 1332 and the vertical edge vertical line V2 is 0.5 mm or less, and the thickness edge 163 is connected to two adjacent punch edges 161 to form a corner 164, and the corner 164 has at least one of 2 mm to 5 mm It is formed to be rounded with a radius of curvature R3 of , and the radius of curvature R3 may be greater than the radius of curvature of the thickness edge. In addition, the depth D of the cup portion 133 may be 6.5 mm or less.

The cup part 133 is formed by molding the pouch film 135 having flexibility using a punch 22 or the like. The cup portion 133 is surrounded by a plurality of outer walls 138 and a bottom portion 1332 , and a space formed by the outer wall 138 and the bottom portion 1332 serves as an accommodating space 1331 for the electrode assembly 10 . ) is accepted.

The outer wall 138 of the cup portion 133 encloses the periphery of the cup portion 133 to specify the shape of the cup portion 133 . The outer wall 138 is formed on the periphery of the cup portion 133 in plurality, is formed on the bridge 136 side, is also formed on the body degassing portion 137 to be described below, and is also formed on the electrode lead 12 side. The outer wall 138 has an upper end facing the opening of the cup portion 133 , and a lower end facing the bottom portion 1332 .

Meanwhile, as described above, the edge 16 of the cup part 133 corresponds to the edge 221 of the punch 22 and the punch edge 161 and the edge 213 of the die 21 are formed in FIG. shown) and a die edge 162 formed thereon. A side 134 and a degassing portion 137 are formed outwardly from the upper end of the outer wall 138 , and the die edge 162 is formed between the upper end of the outer wall 138 and the side 134 or degassing portion 137 . connect each And the punch edge 161 connects the lower end of the outer wall 138 and the bottom portion 1332, respectively.

Since the outer wall 138 of the cup portion 133 is formed in plurality, the edge 16 of the cup portion 133 is also formed in plurality by the number of the outer wall 138 . That is, if the cup portion 133 is formed in a quadrangular shape, since four outer walls 138 of the cup portion 133 are also formed, four punch edges 161 and four die edges 162 are also formed. And according to an embodiment of the present invention, the depth (D) of the cup portion 133 is formed to be 6.5 mm or less, and at least one punch edge 161 of the cup portion 133 is 1 mm or less, particularly 0.7 mm or less. It can be formed and rounded with a radius of curvature.

In particular, according to an embodiment of the present invention, two cup portions 133 are formed on one pouch film 135 , and a bridge 136 is also formed between the two cup portions 133 . Then, as shown in FIG. 5 , among the plurality of punch edges 161 , a bridge 136 connecting the outer wall 1381 and the bottom 1332 on the side of the bridge 136 toward the bridge 136 side to each other. ) side punch edge 1611 may be formed while being rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, the bridge 136 side punch edge 1611 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. In addition, as shown in FIG. 6 , among the plurality of punch edges 161 , the die edge 162 side outer wall facing the die edge 162 formed on the degassing portion 137 or the electrode lead 12 . The punch edge 1612 on the die edge 162 side connecting the 1382 and the bottom 1332 to each other is also rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup part 133, can be formed. Specifically, the punch edge 1612 on the die edge 162 side may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. At this time, at the boundary points (P2, P4) of the punch edge 161 and the outer wall 138, it is preferable that the slope is continuous.

To this end, the edge 221 of the punch 22 may also be rounded with a predetermined radius of curvature. Here, the radius of curvature of the edge 221 of the punch 22 may be a value obtained by subtracting the thickness of the pouch film 135 itself from the radius of curvature R2 of the punch edge 161 . For example, if the thickness of the pouch film 135 is 0.2 mm, when the radius of curvature of the edge 221 of the punch 22 is 0.5 mm or less, the radius of curvature R2 of the punch edge 161 is 0.7 mm or less .

According to an embodiment of the present invention, when the pouch film 135 is draw-molded such that the punch 22 has a depth D of 6.5 mm or less of the cup portion 133, the punch edge 161 of the cup portion 133 is ) to prevent cracks from occurring.

On the other hand, the outer wall 138 has an upper end facing the opening of the cup portion 133 , and the side 134 and the degassing portion 137 extend to the outside of the cup portion 133 . At this time, as shown in FIG. 6 , the cup part 133 may further include a plurality of die edges 162 connecting the upper end of the outer wall 138 and the side 134 or the degassing part 137 , respectively. . In addition, at least one die edge 162 may also be formed while being rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, the at least one die edge 162 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

To this end, the edge 213 of the die 21 may also be rounded with a predetermined radius of curvature. Here, the radius of curvature of the edge 213 of the die 21 may be a value obtained by subtracting the thickness of the pouch film 135 itself from the radius of curvature R2 of the punch edge 161 . For example, if the thickness of the pouch film 135 is 0.2 mm, when the radius of curvature of the edge 213 of the die 21 is 0.5 mm or less, the radius of curvature of the die edge 162 is 0.7 mm or less.

In particular, as described above, the two cup portions 133 may be formed on one pouch film 135 , and the bridge 136 is also formed between the two cup portions 133 . That is, in the pouch-type battery case 13 according to an embodiment of the present invention, the cup portion 133 for accommodating the electrode assembly 10 formed by stacking the electrode 101 and the separator 102 therein is formed, respectively. a first case 131 and a second case 132; and a bridge 136 formed between the two cup portions 133 .

Since the bridge 136 is also formed to correspond to the partition wall 212 of the die 21 , the bridge 136 may be one of the plurality of die edges 162 .

According to an embodiment of the present invention, as the moldability of the pouch film 135 is improved, the bridge 136 may have a thickness of 1/200 to 1/30 of the width of the electrode assembly 10 . . If the thickness t of the bridge 136 is less than 1/200 of the width of the electrode assembly 10 , stress may be excessively concentrated in the bridge 136 to cause cracks, and the thickness t of the bridge 136 may be If the width is greater than 1/30 of the width of the electrode assembly 10 , the bridge 136 is not sharply formed, and thus energy density may decrease.

Specifically, the thickness t of the bridge 136 may be formed to be 2 mm or less, particularly 1.4 mm or less.

Here, the thickness t of the bridge 136 is preferably a distance between the two boundary points P1 of the bridge 136 and the outer wall 1381 on the side of the bridge 136 as shown in FIG. 5 . Specifically, it is preferable that the bridge 136 and the bridge 136 pass through the boundary point P1 of the side outer wall 1381 and be the distance between the two vertical bridge lines V1 perpendicular to the bottom 1332 . Accordingly, when the bridge 136 has a constant radius of curvature, the radius of curvature of the bridge 136 may correspond to half of the thickness t. That is, the radius of curvature of the bridge 136 may be 1 mm or less, particularly 0.7 mm or less.

To this end, a rounding process may be performed with a predetermined radius of curvature of the partition wall 212 of the forming part 211 . At this time, at the boundary point P1 of the bridge 136 and the bridge 136 side outer wall 1381, it is preferable that the slope is continuous. Here, the radius of curvature of the upper surface of the partition wall 212 of the forming part 211 may be a value obtained by subtracting the thickness of the pouch film 135 itself from the radius of curvature of the bridge 136 . For example, when the thickness of the pouch film 135 is 0.2 mm, when the radius of curvature of the upper surface of the partition wall 212 is 0.5 mm or less, the radius of curvature of the bridge 136 is 0.7 mm or less.

According to an embodiment of the present invention, even if the radius of curvature of the edge 213 of the die 21 is reduced and the thickness of the partition wall 212 is formed thin, the depth D of the cup portion 133 is reduced to 6.5 mm or less. forming, it is possible to prevent easily cracks from occurring in the die edge 162 and the bridge 136 . The bridge 136 may have a sector-shaped cross-section, and as the outer wall 138 of the cup part 133 is formed closer to the vertical, the cross-section may have a shape closer to a semicircle.

Furthermore, as the formability of the pouch film 135 is improved, the clearance CL is reduced to 0.5 mm or less, so that the plurality of outer walls 138 may all be formed to be nearly vertical. For example, as shown in FIG. 5 , the bridge 136 side outer wall 1381 may be formed close to vertical among the plurality of outer walls 138 . That is, the bridge 136 and the bridge 136 and the bridge 136, the bridge 136, the bridge passing through the boundary point P1 of the side outer wall 1381 and perpendicular to the bottom portion 1332 (V1), the bridge 136, the side punch edge The clearance (CL), which is the vertical distance between the boundary point P2 of the outer wall 1381 on the side of 1611 and the bridge 136, and between the bottom 1332 and the vertical edge vertical line V2 is 0.5 mm or less, In particular, it may be 0.35 mm or less.

Also, as shown in FIG. 6 , an outer wall 1382 on the side of the die edge 162 among the plurality of outer walls 138 may also be formed close to vertical. That is, a die edge vertical line V4 passing through the boundary point P3 of the die edge 162 and the die edge 162 side outer wall 1382 and perpendicular to the bottom 1332, and the die edge 162 side A clearance CL, which is a vertical distance between the punch edge 1612 and the die edge 162 and the boundary point P4 of the outer wall 1382 on the side of the die edge 162 and between the bottom 1332 and the vertical edge vertical line V2, is 0.5 mm or less, in particular 0.35 mm or less.

Thereby, the depth (D) of the cup portion 133 is molded to be 6.5 mm or less, and the outer wall 138 of the cup portion 133 may have an inclination angle of 90° to 95° from the bottom portion 1332, and , furthermore, it is possible to prevent cracks from occurring in the battery case 13 even if it is formed close to the vertical to have an inclination between 90° and 93°. In addition, since the space 17 between the outer wall 138 of the cup part 133 and the electrode assembly 10 is also reduced, the energy density relative to the volume of the secondary battery 1 may also increase.

Meanwhile, since the radius of curvature R2 of the punch edge 161 of the cup part 133 can be further reduced, even when the electrode assembly 10 is located very close to the outer wall 138 of the cup part 133 , the electrode assembly 10 ) of the electrode 101 can be prevented from being damaged.

To this end, a method of manufacturing a pouch-type secondary battery 1 according to an embodiment of the present invention includes: forming an electrode assembly 10 by stacking an electrode 101 and a separator 102; manufacturing a pouch-type battery case 13 by forming a pouch film 135 to form a cup portion 133; accommodating the electrode assembly 10 in the accommodating space 1331 of the cup part 133; and sealing the side 134 extending outwardly of the cup part 133 to manufacture the pouch-type secondary battery 1 .

In particular, in the step of accommodating the electrode assembly 10, the difference between the width (CW) of the cup part 133 and the width (EW) of the electrode assembly 10 may be 2.5 mm or less, particularly 1.7 mm or less. there is. Here, the width EW of the electrode assembly 10 may mean the width of the electrode 101 . That is, the peripheral portion 1021 protruding from the electrode 101 in the separator 102 may be excluded from the calculation of the width EW.

In addition, at least one end of the electrode 101 passes through the boundary point P2 between the punch edge 161 and the outer wall 138 and from the edge vertical line V2 perpendicular to the bottom portion 1332, The electrode assembly 10 may be accommodated so that the vertical distance g is 0.75 mm, particularly 0.5 mm or less.

Specifically, as shown in FIGS. 5 and 6 , the edge vertical line V2 passing through the boundary point P2 of the punch edge 161 and the outer wall 138 and perpendicular from the bottom part 1332 is shown virtually. In addition, at least one end of the electrode 101 accommodates the electrode assembly 10 so that the vertical distance g from the edge vertical line V2 is 0.75 mm or less, particularly 0.5 mm or less. More specifically, the vertical distance g from the edge vertical line V2 is 0.75 mm, in particular 0.5 mm, and shows a virtual reference vertical line V3 perpendicular to the bottom portion 1332 . At this time, since the radius of curvature R2 of the punch edge 161 may be particularly 0.7 mm or less, the reference vertical line V3 may pass through the center of curvature C of the punch edge 161 . And the electrode assembly 10 is accommodated so that one end of the electrode 101 is positioned between the edge vertical line V2 and the reference vertical line V3. This may be confirmed by disassembling the secondary battery 1 itself, but is not limited thereto and may be confirmed in various ways without disassembling the secondary battery 1, such as CT (Computerized Tomography), MRI (Magnetic Resonance Imaging), X-Ray, etc. there is. As a result, the ratio of the volume of the electrode assembly 10 to the volume of the cup part 133 may be further increased while preventing the electrode 101 from being damaged, and thus the energy efficiency compared to the volume may also be increased. In addition, since an unnecessary volume inside the cup part 133 is reduced, it is possible to prevent the electrode assembly 10 from moving inside the cup part 133 .

Furthermore, since the electrode assembly 10 can be accommodated so as to be located very close to the outer wall 138 of the cup part 133 , the separator 102 may not be disorderly crumpled or folded. As shown in FIG. 5 , the peripheral portion 1021 in which the separator 102 protrudes outward than the electrode 101 is folded toward the opposite direction of the bottom portion 1332 with respect to one end of the electrode 101 . can The electrode assembly 10 is formed by laminating an electrode 101 and a separator 102 , and a plurality of these electrodes 101 and a separator 102 may be formed, respectively. The battery case 13 includes a first case 131 and a second case 132 , and the bridge 136 of the battery case 13 is folded and the upper part of the electrode assembly 10 is also accommodated in the cup part 133 . If yes, the separation membrane 102 accommodated in the cup portion 133 of the first case 131, the peripheral portion 1021, is folded toward the second case 132, the second case 132 ) of the separation membrane 102 accommodated in the cup portion 133 , the peripheral portion 1021 may be folded toward the first case 131 . Thereby, the peripheral portions 1021 of the separation membrane 102 are aligned and folded, so that order can be obtained. In addition, since the separator 102 covers the electrode 101 not to be exposed to the outside, it is also possible to prevent a short circuit from occurring.

In more detail, in a state before the electrode assembly 10 is accommodated in the cup portion 133 , the width of the separator 102 may be wider than the width CW of the cup portion 133 . Accordingly, while the electrode assembly 10 is accommodated in the cup portion 133 , the peripheral portion 1021 of the separator 102 may be folded in a predetermined direction in contact with the inner circumference of the cup portion 133 .

A difference between the width CW of the cup part 133 and the width EW of the electrode assembly 10 may be very small, such as 2.5 mm or less, particularly 1.7 mm or less. Accordingly, a process for easily folding the peripheral portion 1021 of the separator 102 while the electrode assembly 10 is accommodated in the cup portion 133 may be required.

Accordingly, the step of accommodating the electrode assembly 10 in the accommodating space 1331 of the cup part 133 may include pressing the electrode assembly 10 into the cup part 133 . Accordingly, as compared with the conventional method of placing the electrode assembly 10 on the cup portion, the separation membrane 102 while maintaining a small difference between the width CW of the cup portion 133 and the width EW of the electrode assembly 10 . ) by folding in a predetermined direction, the electrode assembly 10 can be easily and reliably accommodated in the accommodating space 1331 of the cup part 133 .

In addition, the step of accommodating the electrode assembly 10 in the receiving space 1331 of the cup part 133 is performed in the electrode assembly 10 before pressing the electrode assembly 10 into the cup part 133 . The method may further include folding each corner (vertex) of the plurality of separation membranes 102 with heat and pressure. In the above process, each corner (vertex) of the plurality of separators 102 may be folded to gather at a central portion in the stacking direction of the electrode assembly 10 using a separate sealing tool.

That is, the electrode assembly 10 may be inserted into the cup portion 133 in a state in which the four corners of the separator 102 are pre-aligned. Accordingly, the electrode assembly 10 may be smoothly inserted into the accommodation space 1331 of the cup part 133 .

As such, according to an embodiment of the present invention, as the moldability of the pouch film 135 is improved, the thickness t of the bridge 136 is made thinner, and the radius of curvature of the edge 16 of the cup part 133 is improved. (R2) and the clearance (CL) may be made smaller, and the volume of the electrode assembly 10 may be increased. Accordingly, since an unnecessary volume in the secondary battery 1 is also reduced, the energy density relative to the volume may be increased. In addition, since the pouch-type battery case 13 and the pouch-type secondary battery 1 may be manufactured in a sharp shape as a whole, the appearance of the secondary battery 1 may also be beautiful and marketability may be improved.

7 is a schematic top view showing a state in which the electrode assembly 10 is accommodated in the cup part 133 according to an embodiment of the present invention.

According to an embodiment of the present invention, as described above, the radius of curvature R2 of the punch edge 161 of the cup portion 133 can be further reduced, so that one end of the electrode 101 is aligned with the edge vertical line V2 and The electrode assembly 10 is accommodated so as to be positioned between the reference vertical lines V3. Accordingly, even when the electrode assembly 10 is located very close to the outer wall 138 of the cup part 133 , it is possible to prevent the electrode 101 of the electrode assembly 10 from being damaged.

The edge vertical line V2 and the reference vertical line V3 may also be illustrated on the bridge 136 side punch edge 1611 , and may also be illustrated on the die edge 162 side punch edge 1612 . The vertical distance g between the edge vertical line V2 and the reference vertical line V3 may be 0.75 mm, particularly 0.5 mm.

In addition, if two cup portions 133 are formed in the battery case 13 , since the bridge 136 is present, a bridge vertical line V1 is drawn on one side of the cup portion 133 , and a die edge vertical line V4 is illustrated on the other side of the cup portion 133 . can do. This vertical distance CL between the bridge vertical line V1 and the edge vertical line V2 may be 0.5 mm or less, in particular 0.35 mm or less, and the vertical distance CL between the die edge vertical line V4 and the edge vertical line V2. 0.5 mm or less, in particular 0.35 mm or less.

However, if only one cup part 133 is formed in the battery case 13 , the bridge does not exist. However, since the die edges 162 are formed on both sides of the cup portion 133 , the die edge vertical lines V4 may be drawn on both sides of the cup portion 133 , respectively.

If two cup portions 133 are formed in the battery case 13 , the width CW of the cup portion 133 may be viewed as a vertical distance from the bridge vertical line V1 to the die edge vertical line V4 . However, if only one cup portion 133 is formed, the width CW of the cup portion 133 may be viewed as a vertical distance between the two die edge vertical lines V4 .

The bridge vertical line V1 and the die edge vertical line V4 both pass through the top of the outer wall 138 of the cup portion 133 . Therefore, according to an embodiment of the present invention, the width CW of the cup portion 133 may be a vertical distance between the upper ends of the outer walls 138 on both sides of the cup portion 133 . The difference between the width CW of the cup part 133 and the width EW of the electrode assembly 10 may be 2.5 mm or less, particularly 1.7 mm or less. And, as described above, the width EW of the electrode assembly 10 may be 60 mm or more.

The width CW of the cup portion 133 may be derived by measuring a vertical distance between the upper ends of the outer walls 138 on both sides of the cup portion 133 in the battery case 13 . And, in the secondary battery 1, using a laser displacement sensor, etc., the position between the upper ends of the outer walls 138 on both sides from the outside of the cup part 133 can be grasped, and the distance between the two positions can be calculated. . At this time, from the outside of the cup part 133, a laser displacement sensor or the like moves from the side 134 toward the die edge 162 and the outer wall 138 while irradiating the laser, and detects a point where the displacement changes rapidly. The corresponding point may be recognized as the upper end of the outer wall 138 . The above describes a method of measuring the width (CW) of the cup portion as an example, and only the case where the method is limited to the above measurement method is not included in the scope of the present invention. The width (CW) of the cup part may be the width (CW) of the cup part in the sense of the present invention as long as it corresponds to the description of the claims and the spirit of the present invention.

8 is a schematic diagram illustrating a conventional corner 364, and FIG. 9 is a schematic diagram illustrating a corner 164 according to an embodiment of the present invention.

The edge 16 of the cup portion 133 is a punch edge 161 and a die edge 162, as well as a thickness edge connecting two adjacent outer walls 138 of the cup portion 133 to each other as shown in FIG. 163). The thickness edge 163 is formed in the thickness direction of the cup portion 133 , and is formed while stretching between the corner of the forming portion 211 of the die 21 and the corner of the punch 22 when the pouch film 135 is stretched. do. Also, at least one of the thickness edges 163 may be rounded.

The thickness edge 163 may have a radius of curvature equal to the radius of curvature R2 of the two punch edges 161 adjacent to each other, that is, the first punch edge 1613 and the second punch edge 1614, but may be different may be formed. For example, while forming the depth D of the cup portion 133 to be 6.5 mm or less as described above, the punch edge 161 is rounded with a radius of curvature of which at least one is 1 mm or less, particularly 0.7 mm or less. The thickness edge 163 may be formed such that at least one is rounded with a radius of curvature of 0.5 mm to 5 mm, in particular 0.5 mm to 2 mm. In the prior art, when the thickness edge 363 is formed to be rounded with a radius of curvature of 5 mm or less, in particular 2 mm or less, stress is also concentrated on the thickness edge 363 of the cup portion 333, and cracks easily occur. However, according to an embodiment of the present invention, it is possible to prevent cracks from occurring in the thickness edge 163 of the cup portion 133 . At this time, one of the first punch edge 1613 and the second punch edge 1614 is the bridge 136 side punch edge 1611 and the other one is the electrode lead 12 side punch edge (not shown). ) can be Alternatively, one of the two may be a punch edge 1612 on the die edge 162 side and the other one may be a punch edge (not shown) on the electrode lead 12 side.

The thickness edge 163 is connected to two punch edges 161 adjacent to each other, that is, the first punch edge 1613 and the second punch edge 1614 as shown in FIG. 9 to form a corner 164 . Conventionally, as shown in FIG. 8 , rounding was performed on the plurality of edges 221 of the punch 22 with the same radius of curvature, and accordingly, the corner (not shown) of the punch 22 naturally also has the same radius of curvature. rounding has been done. Accordingly, when the pouch film 135 is stretched by molding the pouch film 135 with the punch 22 , the corner 364 is naturally rounded with the same radius of curvature as the punch edge 361 .

However, there is a problem in that stress is concentrated in the corner 364 when the pouch film 135 is stretched. In particular, since the corner 364 is formed by the three edges 361 meeting, the elongation is greater than the punch edge 361 or the thickness edge 363 , so that the punch edge 361 or the thickness edge 363 is more stressed than the punch edge 361 or the thickness edge 363 . This was a lot of focus. Accordingly, excessive stretching of the pouch film 135 causes a whitening phenomenon in which a specific portion changes to white immediately before cracks occur, and eventually cracks easily occur.

Therefore, according to an embodiment of the present invention, as shown in Fig. 12, the corner 164 is also formed with at least one rounding, and the corner 164 has a radius of curvature of the punch edge 161 and the thickness edge. It may be greater than or equal to a radius of curvature of at least one of (163).

Specifically, according to an embodiment of the present invention, the radius of curvature of the corner 164 may be changed inside. That is, the radius of curvature of the central portion 1641 of the corner 164 and the radius of curvature of the peripheral portion 1642 of the corner 164 may be different from each other. In particular, the radius of curvature of the central portion 1641 of the corner 164 may be greater than the radius of curvature of the peripheral portion 1642 of the corner 164 . For example, the radius of curvature of the perimeter 1642 of the corner 164 is relatively adjacent to the first punch edge 1613 , the second punch edge 1614 , and the thickness edge 163 , and thus the punch edge 161 . and a radius of curvature of at least one of the thickness edges 163 . On the other hand, since the radius of curvature of the central portion 1641 of the corner 164 is relatively spaced apart from the first punch edge 1613 , the second punch edge 1614 and the thickness edge 163 , the punch edge 161 and the thickness It may be greater than a radius of curvature of at least one of the edges 163 . That is, the corner 164 may have a radius of curvature equal to or greater than a radius of curvature of at least one of the punch edge 161 and the thickness edge 163 .

Accordingly, the radius of curvature of the corner 164 may gradually increase from the peripheral portion 1642 of the corner 164 to the central portion 1641 of the corner 164 . And, as described above, since the radius of curvature of the corner 164 is not constant and changes inside, the center 1641 of the corner 164 may have an aspherical shape rather than an exact spherical shape.

Unlike the punch edge 161 , the corner 164 must be clearly set in the range formed in the cup portion 133 as well as the radius of curvature. If the range in which the corner 164 is formed in the cup portion 133 is excessively narrow, the pouch film 135 is still excessively stretched, causing a problem of whitening or cracking. On the other hand, if the range in which the corner 164 is formed in the cup portion 133 is excessively wide, the space 17 between the outer wall 138 of the cup portion 133 and the electrode assembly 10 decreases, so the rechargeable battery 1 ) can increase the energy density relative to the volume. Accordingly, according to an embodiment of the present invention, as shown in FIG. 12 , the corner 164 is 2 mm to 3.5 mm in the longitudinal direction lc of the cup portion 133 from the thickness edge 163 , the thickness edge 163 . ) from 2 mm to 3.5 mm in the width direction (wc) of the cup part 133, and 2 mm to 3.5 mm in the thickness direction (dc) of the cup part 133 from the punch edge 161. In addition, the range in which the corner 164 is formed may gradually widen as the depth D of the cup portion 133 increases.

Since the corner 164 of the cup portion 133 is formed as described above, stress more concentrated in the corner 164 may be dispersed, thereby preventing the problem of whitening and cracks occurring.

10 is a schematic diagram showing a state in which the battery case 13 according to an embodiment of the present invention is folded, and FIG. 11 is a schematic diagram showing a state in which the battery case 13 according to an embodiment of the present invention is folded.

When the two cup portions 133 are formed in the pouch film 135 , the cup portions 133 are respectively formed in the first case 131 and the second case 132 of the battery case 13 . After accommodating the electrode assembly 10 in the accommodating space 1331 provided in the cup portion 133 of the first case 131 , as shown in FIG. 10 , the battery case so that the two cup portions 133 face each other In (13), the bridge 136 formed between the two cup parts 133 is folded. As the bridge 136 is folded, a folding part 139 is formed at one side of the secondary battery 1 . Then, as shown in FIG. 11 , a pouch-type secondary battery is injected by injecting an electrolyte therein and sealing the side 134 extending outwardly of the cup part 133 of the first case 131 and the second case 132 . (1) can be prepared.

The pouch-type secondary battery 1 according to an embodiment of the present invention manufactured as described above includes an electrode assembly 10 in which an electrode 101 and a separator 102 are stacked; and a pouch-type battery case 13 having a cup portion 133 for accommodating the electrode assembly 10 therein, wherein the cup portion 133 includes a plurality of outer walls 138 and a bottom portion ( 1332 may include a plurality of punch edges 161 for connecting, respectively. At least one of the punch edges 161 may be rounded and formed with a radius of curvature of 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, at least one of the punch edges 161 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. A difference between the width CW of the cup part 133 and the width EW of the electrode assembly 10 may be 2.5 mm or less, particularly 1.7 mm or less. In addition, in the electrode assembly 10 , at least one end of the electrode 101 passes through a boundary point P2 between the punch edge 161 and the outer wall 138 and is perpendicular to the bottom 1332 . The vertical distance g from the in-edge vertical line V2 may be 0.75 mm, particularly 0.5 mm or less. In addition, the battery case 13 includes a first case 131 and a second case 132 each having a cup portion 133 formed on at least one; and a folding part 139 for integrally connecting the first case 131 and the second case 132 .

When the secondary battery 1 is manufactured by folding the battery case 13 , the bridge 136 becomes the folding part 139 , so in the secondary battery 1 , the folding part 139 is formed between the first case 131 and the second battery 1 . 2 The case 132 is integrally connected. And the bridge 136 side punch edge 1611 is the folding part 139 side punch edge 1611, the bridge 136 side outer wall 1381 becomes the folding part 139 side outer wall 1381.

Then, among the plurality of punch edges 161, the folding part 139 side punch edge ( 1611 ) may be formed while being rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, the punch edge 1611 on the side of the folding part 139 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. In addition, in the electrode assembly 10 , at least one end of the electrode 101 passes through the boundary point P2 between the punch edge 161 and the outer wall 138 , and is perpendicular to the bottom 1332 . The edge vertical line V2 and the vertical distance g from the edge vertical line V2 may be 0.75 mm, particularly 0.5 mm, and may be located between the bottom portion 1332 and the vertical reference vertical line V3. As described above, this reference vertical line V3 may pass through the center of curvature C of the punch edge 161 .

12 is an enlarged view of the groove 1391 formed in the battery case 13 according to an embodiment of the present invention.

According to an embodiment of the present invention, when the battery case 13 is folded to manufacture the secondary battery 1 as described above, the bridge 136 may be in the form of the folding part 139 . Specifically, when the battery case 13 is folded, the rounded shape of the bridge 136 is also spread to some extent, but traces of the bridge 136 are left on the secondary battery 1, and these traces are the folding part 139 . can be Accordingly, the bridge 136 and the folding part 139 of the battery case 13 may correspond to each other.

For example, if the rounded shape of the bridge 136 is not completely flattened in a plane, the folding part 139 includes a groove 1391 recessed inward of the secondary battery 1 as shown in FIG. 12 . is formed by In this case, since the folding part 139 has a smaller curvature than the bridge 136 , it may have a larger radius of curvature.

Since the bridge 136 has a curved surface, and the bridge 136 side outer wall 1381 has a planar shape, the amount of deformation is different from each other. Therefore, when the battery case 13 is folded, the bridge 136 side outer wall 1381 is deformed relatively much, but the bridge 136 is deformed relatively little only to the extent that the rounded shape is stretched to some extent. Then, when the battery case 13 is folded, as shown in FIG. 12 , the increase/decrease in the change amount of the inclination is switched around the boundary point P1 . That is, each of the boundary points P1 becomes an inflection point. Accordingly, the folding part 139 may be formed as a curved surface between the two boundary points P1, that is, the two inflection points.

In addition, when the rounded shape of the bridge 136 is not completely flattened, the two boundary points P1 , that is, portions corresponding to the two inflection points may protrude outward to form a protrusion. That is, the protrusion may be formed as a pair of protruding portions protruding to the outside with the folding portion 139, more specifically, the groove 1391 interposed therebetween.

Alternatively, even if the rounded shape of the bridge 136 is completely flattened in a plane, the boundary point P1 of the bridge 136 and the outer wall 1381 on the side of the bridge 136 is two lines (not shown) in the secondary battery 1, respectively. city), and the folding part 139 is formed as a plane between these two lines.

The folding part 139 may be visually confirmed from the external appearance of the secondary battery 1 . And as described above, the thickness t of the bridge 136 is preferably the distance between the bridge 136 and the two boundary points P1 of the bridge 136 side outer wall 1381, so the folding part 139 The width FW of is the distance between the two boundary points P1. That is, when the rounded shape of the bridge 136 is not completely flattened out, the width FW of the folding part 139 is the two boundary points P1, that is, the distance between the two inflection points. Alternatively, when the rounded shape of the bridge 136 is completely flattened, the folding part 139 is the two boundary points P1, that is, the distance between the two lines.

The width FW of the folding part 139 does not exceed the length of the bridge 136, and may be 1 mm to 3.2 mm, in particular 1 mm to 1.6 mm. As described above, the width FW of the folding part 139 may be measured using a direct ruler, but may also be measured using a loupe, or measured using a 3D camera or a laser 2D line sensor. It can be measured in various ways without being limited, such as being able to do it.

Conventionally, the thickness t' of the bridge 336 is formed to be thick, and the width of the folding part 339 is also formed to be large, and accordingly, the space 37 between the outer wall 338 of the cup part 333 and the electrode assembly 10. also formed large. However, according to an embodiment of the present invention, since the width FW of the folding part 139 may be reduced, the space 17 between the outer wall 138 of the cup part 133 and the electrode assembly 10 may also be reduced. can Accordingly, the energy density relative to the volume of the secondary battery 1 may be increased.

In addition, since the moldability of the pouch film is low in the related art, the protrusion largely protrudes outward. However, according to an embodiment of the present invention, the protrusion may protrude relatively small, and the flatness of the folding part 139 or the outer wall 1381 on the side of the folding part 139 may be improved.

Specifically, a distance p between the innermost portion of the groove 1391 and the outermost portion of the protrusion may be defined as flatness. In the case of a conventional battery case, the flatness is 1 mm or more and even 1.5 mm is formed. On the other hand, according to an embodiment of the present invention, the flatness p may be formed to be 0.8 mm or less, preferably 0.3 mm or less. Accordingly, the energy density relative to the volume of the secondary battery 1 may be further increased.

13 is an enlarged schematic view of the cup portion 133 and the die edge 1621 according to another embodiment of the present invention.

According to an embodiment of the present invention, two molded parts 211 are formed adjacent to each other on the die 21 , and a partition wall 212 may be formed between the two molded parts 211 . Accordingly, when the pouch film 135 is formed, two cup portions 133 are formed in one pouch film 135 , and a bridge 136 is also formed between the two cup portions 133 . That is, one cup part 133 is formed in each of the first case 131 and the second case 132 .

However, according to another embodiment of the present invention, only one molding part 211 is formed on the die 21 , and there is no partition wall. Accordingly, when the pouch film 135 is formed, one cup portion 133 is formed in one pouch film 135 , and there is no bridge. That is, the cup portion 133 is formed only in the first case 131 .

According to another embodiment of the present invention, the depth (D) of the cup portion 133 is molded to be 6.5 mm or less, and at least one punch edge 161a of the cup portion 133 is the depth D of the cup portion 133 . ) may be rounded and formed with a radius of curvature of 1/20 to 1/6. Specifically, at least one of the punch edges 161a of the cup part 133 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. Accordingly, it is possible to prevent cracks from easily occurring in the punch edge 161a of the cup portion 133 .

In particular, according to another embodiment of the present invention, as shown in FIG. 13, among the plurality of punch edges 161a, the second case 132a side facing the second case 132a side outer wall 1381a and the bottom The punch edge 1611a on the side of the second case 132a connecting the portions 1332 to each other may be formed while being rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, the punch edge 1611a on the side of the second case 132a may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

In addition, the die edge 162 side punch edge 1612 may also be formed while being rounded with a radius of curvature that is 1/20 to 1/6 of the depth D of the cup portion 133 . Specifically, the punch edge 1612 on the die edge 162 side may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. At this time, at the boundary point P2 of the punch edge 161a and the outer wall 138, it is preferable that the inclination is continuous.

Hereinafter, with respect to another embodiment of the present invention, descriptions of contents overlapping with one embodiment of the present invention will be omitted. However, this is for convenience of explanation and is not intended to limit the scope of rights.

14 is a schematic diagram showing a state in which the battery case 13a according to another embodiment of the present invention is folded, and FIG. 15 is a schematic diagram showing a state in which the battery case 13a according to another embodiment of the present invention is folded.

The outer wall 138 has an upper end facing the open portion of the cup portion 133 , and the second case 132a , the side 134 , and the degassing portion 137 extend to the outside of the cup portion 133 . At this time, the die edge 162 connecting the upper end of the outer wall 138 and the second case 132a, the side 134 or the degassing part 137 is also 1/20 to 1/20 of the depth D of the cup part 133 . It can be rounded and formed with a radius of curvature equal to 1/6. Specifically, the die edge 162 may be rounded and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

That is, according to another embodiment of the present invention, as shown in FIG. 14 , there is no bridge in the battery case 13a , and the die edge 1621 is formed between the cup portion 133 of the first case 131 and the second The cases 132a are connected to each other. To this end, the edge 213 of the die 21 may be rounded with a radius of curvature obtained by subtracting the thickness of the pouch film 135 from the die edge 162 . For example, if the thickness of the pouch film 135 is 0.2 mm, the edge 213 of the die 21 may be rounded with a radius of curvature of 0.8 mm or less, particularly 0.5 mm or less.

Furthermore, by reducing the clearance CL to 0.5 mm or less, the outer wall 138 of the cup part 133 may be formed to be close to vertical. For example, as shown in FIG. 13 , the die edge vertical line V4 passes through the boundary point P1 between the die edge 1621 and the second case 132a side outer wall 1381a and is perpendicular to the bottom 1332 . ) and the second case 132a side punch edge 1611a and the second case 132a side outer wall 1381a passing through the boundary point P2 and perpendicular to the bottom 1332 edge vertical line V2 ), the clearance (CL) being the vertical distance between them may be 0.5 mm or less, in particular 0.35 mm or less.

In addition, one end of the electrode 101 has a vertical distance of 0.75 mm, particularly 0.5 mm, from the edge vertical line V2 and the edge vertical line V2, and between the bottom portion 1332 and the vertical reference vertical line V3. The electrode assembly 10 may be accommodated so as to be positioned.

Thus, according to another embodiment of the present invention, the depth (D) of the cup portion 133 is molded to be 6.5 mm or less, and the outer wall 138 of the cup portion 133 has an inclination angle of 90° to 95° from the bottom portion 1332 . , In particular, it is formed close to vertical to have an inclination between 90° and 93°, and the volume ratio of the electrode assembly 10 to the volume of the cup part 133 can be further increased while preventing the electrode 101 from being damaged. , the energy efficiency to volume ratio can also be increased.

16 is an enlarged view of the groove 1391a formed in the battery case 13a according to another embodiment of the present invention.

According to another embodiment of the present invention, when the battery case 13a is folded to manufacture the secondary battery 1a , the die edge 1621 on the second case 132a side becomes the folding part 139a. Specifically, when the battery case 13 is folded, the rounded shape of the die edge 1621 is also unfolded, but traces of the die edge 1621 remain in the secondary battery 1a, and these traces are the folding part 139a. becomes Accordingly, the die edge 1621 on the second case 132a side of the battery case 13a and the folding part 139a correspond to each other.

For example, if the rounded shape of the die edge 1621 is not completely flattened out, the folding part 139a may form a groove 1391a recessed inward of the secondary battery 1a as shown in FIG. 19 . formed by including In this case, the folding part 139a has a smaller curvature than the die edge 1621 , and thus may have a larger radius of curvature.

Since the die edge 1621 has a curved surface and the outer wall 1381a on the side of the die edge 1621 has a planar shape, deformation amounts are different from each other. Therefore, when the battery case 13 is folded, the die edge 1621 side outer wall 1381a is deformed relatively much, but the die edge 1621 is deformed relatively little only to the extent that the rounded shape is spread to some extent. Then, when the battery case 13 is folded, as shown in FIG. 19 , the increase/decrease in the change amount of the inclination is switched around the boundary point P1 . That is, each of the boundary points P1 becomes an inflection point. Accordingly, the folding part 139a is formed as a curved surface between the two boundary points P1, that is, the two inflection points.

Alternatively, even if the rounded shape of the die edge 1621 is completely flattened in a plane, the boundary point P1 of the die edge 1621 and the second case 132a side outer wall 1381, the die edge 1621 and the second The boundary points of the two cases 132a form two lines (not shown) in the secondary battery 1a, respectively, and the folding part 139a is formed as a plane between the two lines.

The width FW of the folding part 139 does not exceed the length of the die edge 1621 and may be 1 mm to 3.2 mm, in particular 1 mm to 1.6 mm.

17 is a schematic diagram showing the state before cutting the degassing unit 337 of the conventional battery case 33 from above.

The bridge 136 of the battery case 13 is folded to form a folding part 139 on one side of the secondary battery 1 , and the folding part 139 includes the first case 131 and the second case 132 . connect them together However, the battery case 13 is formed by drawing-molding the pouch film 135 , and in this case, not only the cup portion 133 is limitedly stretched, but the peripheral sides 134 of the cup portion 133 are also finely stretched as a whole. . Accordingly, when the bridge 136 is folded, the finely elongated portions of the sides 134 are accumulated and appear visually while protruding outward from a portion of both ends of the folding part 139 . This is called a bat ear (35 or 15).

The size of the bat ear 35 is the thickness (t') of the bridge 336, the clearance (CL'), the radius of curvature (R2') of the punch edge 361 of the cup part 333, and the depth of the cup part 333 ( D'). That is, the thicker the thickness t' of the bridge 336, the greater the clearance CL', the greater the radius of curvature R2' of the punch edge 361 of the cup part 333, the greater the size also increases. However, there is a limit in improving the thickness (t') of the bridge (336), the radius of curvature (R2') and the clearance (CL') of the punch edge 361 of the cup part 333 in the prior art. Therefore, as shown in FIG. 17, the size of the bat ear 35 was formed to be quite large, and there was also a limit to reducing it.

When the size of the bat-ear 35 is formed to be large, an unnecessary volume of the secondary battery 3 is further increased, so that an error occurs in the design value and the actual value of the shape and size of the secondary battery 3 . Therefore, when assembling the secondary batteries 3 to the battery module 5 (shown in FIG. 24), it is not easy to assemble, and the size of the secondary battery 3 must be designed small from the beginning in consideration of the bat-ear 35. there was a problem with In addition, since the volume of the secondary battery 3 is increased, there is also a problem in that the energy density relative to the volume decreases.

Meanwhile, as described above, the pouch-type battery case 13 according to an embodiment of the present invention includes a cup portion 133 having an accommodation space 1331 accommodating the electrode assembly 10 , and one side of the cup portion 133 . and a degassing unit 137 for discharging gas generated in the cup unit 133 through the degassing hole H.

In addition, in the process of sealing the side 134 , a formation process and a degassing process may be performed. Specifically, after the electrode assembly 10 is accommodated in the cup part 133 , in the battery case 13 , the corner 1371 included in the degassing part 137 is opened, and the remaining side 134 is sealed. can do. When the opening is formed by opening the edge 1371 of the battery case 13 , the electrolyte is injected into the battery case 13 through the opening.

After injecting the electrolyte into the battery case 13 , the degassing unit 137 is first sealed to form the temporary sealing unit 1340 . Since the sealing part 1341 is formed by the secondary sealing of the degassing part 137 later, it is preferable that the temporary sealing part 1340 is formed in the degassing part 137 at a position close to the edge 1371 .

After that, an activation (Formation) process may be performed. The activation process (formation process) is a process of finally completing charging so that the secondary battery 1 can supply electric power. Since the activation process is performed after the temporary sealing part 1340 is formed and the battery case 13 is completely sealed, the charging rate is high and the gas is rapidly discharged to complete the manufacture of the secondary battery 1 within the predetermined process time. there is.

When the activation process is completed, gas is generated inside the battery case 13 . Accordingly, a degassing hole H is punched in the degassing portion 137 of the battery case 13 . Through these degassing holes H, gas is discharged from the inside of the battery case 13 to the outside. At this time, the injected electrolyte may leak through the degassing hole H while the gas is easily discharged. In order to prevent this, it is preferable that the degassing hole H is perforated at a position close to the temporary sealing part 1340 . When the degassing hole H is drilled, a degassing process of discharging the gas to the outside of the battery case 13 is performed.

When the degassing hole H is perforated, the inside of the battery case 13 is opened again, and the electrolyte inside may leak to the outside. Accordingly, the sealing portion 1341 is formed by secondary sealing the boundary between the cup portion 133 and the degassing portion 137 . In this case, the sealing part 1341 is formed between the cup part 133 and the degassing hole H, and is preferably formed in a position close to the cup part 133 .

As described above, while performing the activation process and the degassing process, the degassing hole H must be drilled, and primary sealing and secondary sealing must be performed. Furthermore, when mass-producing the secondary batteries 1 , it is necessary to collectively manage the specifications and quality of the secondary batteries 1 . To this end, the battery case 13 or the secondary battery 1 may be inspected using the inspection device 4 (shown in FIG. 19 ) including the vision sensor 41 .

Conventionally, there is a limit in manufacturing the battery case 33 and the secondary battery 3 as a whole in a sharp shape. Therefore, when the battery case 33 is photographed with the vision sensor, errors in the size and position of each component are large.

Specifically, when the manufacture of the secondary battery 1 is completed later, the battery module 5 (shown in FIG. 24 ) may be manufactured by connecting the electrode leads 12 of the plurality of secondary batteries 1 to each other. To this end, the positions of the electrode leads 12 formed in the plurality of secondary batteries 1 should all be constant. However, in the related art, since the electrode 101 is spaced apart from the outer wall 338 of the cup part 333 to some extent, the electrode assembly 10 can move inside the cup part 333 before sealing the side 134 . Therefore, when the secondary batteries 3 are mass-produced, even though the volume of the cup part 333 and the volume of the electrode assembly 10 are all constant, the position of the electrode assembly 10 is slightly different, so that the position of the electrode lead 12 is were also slightly different. Therefore, it is necessary to accurately measure the position of the electrode lead 12 using the inspection device 4 .

In addition, in order to drill the degassing hole H at an accurate position and size, and perform the primary sealing and the secondary sealing at the correct position and size, the position of the degassing unit 137 must be accurately measured. In addition, in order to efficiently manage the overall quality of the plurality of secondary batteries 1 , the battery case 13 , such as the side 134 , the folding part 139 , and the insulating part 14 protruding from the battery case 13 . Alternatively, the positions of the various components of the secondary battery 1 and even the widths between the cup portions 133 should be accurately measured.

In order to measure the positions of the components, it is necessary to set a specific reference line and measure the vertical distance from the reference line to the component to be measured. For example, when the electrode assembly 10 moves inside the cup part 333 , in general, in a left and right direction based on the bar shown in FIG. 17 , that is, in a direction toward the folding part 339 and the degassing part 337 . often moving. Therefore, in order to measure the position of the electrode lead 12, it is necessary to measure the position of the left or right edge of the electrode lead 12, and to measure the vertical distance to the left or right edge, the left or right edge and Parallel standards should be established.

However, in the prior art, since the outer wall 338 of the cup part 333 is not formed close to vertical and the radius of curvature R2' of the punch edge 361 of the cup part 333 is also large, the battery case ( 33), in the image, the punch edge 361 of the cup part 333 did not appear clearly as shown in FIG. 20 . Therefore, the positions of the components could not be measured based on the punch edge 361 of the cup part 333, and the bat ear 35 close to the punch edge 361 was set as a reference, or the user manually manually set the cup part. The punch edge 361 of (333) was set as a reference.

However, since the bat-ear 35 is formed by folding the bridge 136 in a state in which the peripheral sides 134 of the cup part 133 are also slightly elongated as a whole, the bat-ear 35 for each of the plurality of secondary batteries 1 . ) was slightly different in size. Then, even when the positions of the components are measured with the vision sensor, since the size of the bat-ear 35 as a reference is different, the deviation of the positions of the components between the secondary batteries 3 increases, making quality control difficult.

In particular, even when the position of the electrode lead 12 is measured by photographing the battery case 33 with a vision sensor, the position of the electrode lead 12 is slightly different, so that the electrode leads 12 are used to manufacture the battery module 5 . When connecting, there was a problem that the connection was not easy. In addition, in order to manufacture the battery module 5, when a plurality of secondary batteries 1 are sequentially stacked or aligned in a line, the position of the cup part 333 is not correct, so the alignment of the plurality of secondary batteries 1 is also There was also the problem of lowering.

In the case of manufacturing the battery module 5 by accommodating the secondary batteries 3 in a separate housing 51 (shown in FIG. 24 ), the deviation of the measured values is large, so the design tolerance when designing the housing 51 . is set unnecessarily large, there was also a problem in that the energy density compared to the volume of the battery module 5 is also lowered.

18 is a schematic diagram showing a state from above before cutting the degassing unit 137 of the battery case 13 according to an embodiment of the present invention, and FIG. 19 is an inspection device 4 according to an embodiment of the present invention. ) is a block diagram of

According to an embodiment of the present invention, as shown in FIG. 18 , as the formability of the pouch film 135 is improved, the thickness t of the bridge 136 is made thinner, and the punch edge ( 1611), the radius of curvature R2 and the clearance CL may be made smaller, and accordingly, the size of the bat ear 15 may be further reduced. Accordingly, the secondary batteries 1 can be easily assembled into the battery module 5 , and since an unnecessary volume of the secondary battery 1 is reduced, the energy density relative to the volume can be increased.

In addition, according to an embodiment of the present invention, as shown in FIG. 18 , since the punch edge 1611 of the cup part 133 is clearly displayed in the image obtained by photographing the battery case 13 , the inspection device 4 is The punch edge 161 of the cup part 133 can be automatically set as the reference line ST, and various configurations of the battery case 13 or the secondary battery 1 based on the punch edge 161 of the cup part 133 . The distance to the fields can be accurately measured, and further, even the width (CW) between the cup parts 133 can be accurately measured. Accordingly, by accurately measuring the positions of the components of the battery case 13 or the secondary battery 1 , an error in a measurement value may be reduced and a deviation between the secondary batteries 1 may also be reduced.

To this end, the battery case 13 or the secondary battery 1 inspection apparatus 4 according to an embodiment of the present invention photographs the battery case 13 and inspects the battery case 13 or the secondary battery 1 . a vision sensor 41 for acquiring an image; an outline extraction unit 421 for extracting outlines of the components of the battery case 13 or the secondary battery 1 from the image; Image analysis for analyzing the image to detect the outline corresponding to the punch edge 161 of the cup part 133 in which the accommodating space 1331 accommodating the electrode assembly 10 is provided in the battery case 13 . part 422; a reference line setting unit 423 for setting the outline corresponding to the punch edge 161 as a reference line ST; and a distance calculating unit 424 for calculating a distance from the reference line ST to the components.

And, in the inspection method of the battery case 13 or the secondary battery 1 according to an embodiment of the present invention using the inspection device 4, the vision sensor 41 captures the battery case 13 and the battery case ( 13) or acquiring an image of the secondary battery (1); extracting, by the outline extraction unit 421, outlines of the components of the battery case 13 or the secondary battery 1 from the image; The image analysis unit 422 analyzes the image, and the accommodating space 1331 accommodating the electrode assembly 10 in the battery case 13 is provided, which corresponds to the punch edge 161 of the cup unit 133 . detecting an outline; setting, by the reference line setting unit 423, the outline corresponding to the punch edge 161 as a reference line (ST); and calculating, by the distance calculating unit 424, the distances from the reference line ST to the components.

Specifically, the inspection apparatus 4 includes a vision sensor 41 and a controller 42 as shown in FIG. 19 . In addition, these components may be connected to each other through a bus (not shown) to communicate. All components included in the control unit 42 may be connected to the bus through at least one interface or adapter, or may be directly connected to the bus. In addition, the bus may be connected to other subsystems in addition to the above-described components. These buses include a memory bus, a memory controller, a peripheral bus, and a local bus.

The vision sensor 41 acquires an image by photographing a specific area and receiving an image signal for the specific area. To this end, in general, the vision sensor 41 includes an imaging device such as a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) image sensor. In particular, in the vision sensor 41 according to an embodiment of the present invention, after the bridge 136 of the battery case 13 is folded, the battery case 13 is photographed to obtain the battery case 13 or the secondary battery 1 . ) of each component can be acquired. Here, the components include the above-described cup part 133, degassing part 137, electrode lead 12, bat ear 15, side 134, folding part 139 and insulating part 14, etc. include Then, by cutting the degassing unit 137 later, the manufacture of the secondary battery 1 is completed. Therefore, if the vision sensor 41 captures the battery case 13 before cutting the degassing unit 137 , images of the battery case 13 and the electrode lead 12 may be acquired, and the degassing unit If the battery case 13 is photographed after cutting 137 , an image of the secondary battery 1 can be obtained.

The controller 42 receives the image signal obtained by the vision sensor 41 , and recognizes the positions of each component of the battery case 13 or the secondary battery 1 from the image signal. The control unit 42 includes an outline extracting unit 421 , an image analyzing unit 422 , a reference line setting unit 423 , and a distance calculating unit 424 . It is preferable to use a central processing unit (CPU), a micro controller unit (MCU), a digital signal processor (DSP), or the like as the control unit 42 , but the present invention is not limited thereto, and various logical processing processors may be used.

The outline extractor 421 extracts outlines of components of the battery case 13 or the secondary battery 1 from the image received from the vision sensor 41 . At this time, the outline extraction unit 421 may extract the outlines of all components appearing in the image, but is not limited thereto, and an ROI (Region Of Interest) is set in a part of the image, and It is also possible to extract only the outline. In order to extract the outline, information about the pixels of the image is first extracted, and for this purpose, a gradient formula generally used may be used. The outline of the battery case 13 and the electrode lead 12 is revealed through the extracted pixel information.

According to one embodiment of the present invention, the radius of curvature R2 and the clearance CL of the punch edge 161 of the cup portion 133 can be formed smaller, and the outer wall 138 of the cup portion 133 is perpendicular to the Since they may be formed close together, the gradient of pixel information corresponding to the punch edge 161 of the cup part 133 in the image is large. Accordingly, since the boundary between the outline and the background is clear, the outline corresponding to the punch edge 161 of the cup part 133 can be clearly extracted.

The image analysis unit 422 analyzes the image to detect an outline corresponding to the punch edge 161 of the cup unit 133 in the battery case 13 . To this end, the image analysis unit 422 matches the pre-stored reference outline information of the punch edge 161 of the cup portion 133 with the extracted outline information, and the punch edge 161 of the cup portion 133 is performed. It is possible to detect an outline corresponding to . In this case, the image analyzer 422 may match the two pieces of information using a template matching technique.

The reference line setting unit 423 may set the outline corresponding to the punch edge 161 as the reference line ST. Since the cup part 133 includes a plurality of punch edges 161 , a plurality of outlines corresponding to the punch edges 161 are also extracted. At this time, in order to accurately measure the positions of the respective components of the battery case 13 or the secondary battery 1 , the reference line setting unit 423 is the closest to the component to be measured among the plurality of punch edges 161 . It is preferable to set the outline corresponding to the punch edge 161 as the reference line ST. In addition, as described above, since the positions of the components have to measure the vertical distance from the reference line ST, the reference line setting unit 423 includes the corners of the components to be measured among the plurality of punch edges 161 and The outline corresponding to the parallel punch edge 161 may be set as the reference line ST.

For example, in order to drill the degassing hole H and perform primary sealing and secondary sealing, the inspection device 4 may have to measure the position of the degassing unit 137 . In this case, the reference line setting unit 423 is close to the degassing unit 137 among the plurality of punch edges 161 and parallel to the edge 1371 included in the degassing unit 137, the die edge The outline corresponding to the (162) side punch edge 1612 may be set as the reference line ST.

And, for example, in order to inspect whether the positions of the electrode leads 12 are all constant, the inspection apparatus 4 may have to measure the positions of the electrode leads 12 . In this case, the reference line setting unit 423 is close to the electrode lead 12 among the plurality of punch edges 161 and parallel to the left or right edge of the electrode lead 12, the folding unit 139 side An outline on the side of the electrode lead 12 corresponding to the punch edge 1611 may be set as the reference line ST.

Furthermore, in order to measure the width between the cup portions 133 , the reference line setting unit 423 includes the two punch edges 161 corresponding to the boundary of the width of the cup portion 133 among the plurality of punch edges 161 . The outline of any one of the lines may be set as the reference line ST.

That is, as long as the reference line setting unit 423 can accurately measure the positions of the respective components of the battery case 13 or the secondary battery 1 , the reference line setting unit 423 is not limited and may set various outlines as the reference line ST.

The distance calculating unit 424 calculates a distance from the reference line ST to the respective components of the battery case 13 or the secondary battery 1 in the image. For example, if the outline corresponding to the punch edge 1612 on the die edge 162 side is set as the reference line ST, the distance calculating unit 424 from the reference line ST to the degassing unit 137. The distance to the included edge can be calculated. Alternatively, if the outline corresponding to the punch edge 1611 on the side of the folding unit 139 is set as the reference line ST, the distance calculating unit 424 is from the reference line ST to one edge of the electrode lead 12 . The distance may be calculated, and the distance to the outline corresponding to the punch edge 1612 on the side of the die edge 162 may be calculated.

The distance calculating unit 424 may use information about the relationship between the number of pixels in the image stored in advance and the actual distance. That is, in the image, the distance calculating unit 424 counts the distance from the reference line ST to the respective elements in the number of pixels, and then using information on the relationship between the number of pixels in the image and the actual distance stored in advance. , an actual distance corresponding to the counted number of pixels may be calculated.

The test device 4 may further include a storage unit 44 . The storage unit 44 stores a program for processing and controlling operations of the inspection device 4 and various data or received signals generated during execution of each program. In particular, reference information about the battery case 13 may be stored so that the image analysis unit 422 may detect an outline corresponding to the punch edge 1611 of the cup unit 133 . Here, the reference information about the battery case 13 includes reference outline information about the punch edge 1611 of the cup part 133 and the distance to the components of the battery case 13 or the secondary battery 1 . It may include reference information and the like. This may be directly stored in the storage unit 44 by the user, or the test apparatus 4 may generate and store the reference information through repeated learning. In addition, the storage unit 44 may store information on the relationship between the number of pixels in the image and the actual distance so that the distance calculating unit 424 can calculate the actual distance from the reference line ST to each component. Furthermore, it is also possible to store inspection result information of the battery case 13 to be inspected. This storage unit 44 may be built in the test device 4, it may be provided as a separate storage server. The storage unit 44 includes a non-volatile memory device and a volatile memory device. The non-volatile memory device may be a NAND flash memory having a small volume, light weight, and strong resistance to external impact, and the volatile memory device may be a DDR SDRAM.

The control unit 42 may further include a failure determination unit 425 for determining whether the battery case 13 to be inspected is defective. The failure determining unit 425 may compare the reference information about the battery case 13 stored in the storage unit 44 with the inspection result information of the battery case 13 to be inspected. And, when the test result information is included within the error range of the reference information, it is determined that the battery case 13 is normal. However, if the inspection result information is out of the error range of the reference information, it is determined that the battery case 13 is defective.

Meanwhile, the test apparatus 4 may further include a display unit 43 for receiving and displaying an image signal. The display unit 43 receives the signal of the image and displays it to the user. Furthermore, when the outline extraction unit 421 extracts the outline of the battery case 13 , the outline is displayed on the image so that the user may check it through the display unit 43 . The display unit 43 may use various methods such as a liquid crystal display (LCD), an organic liquid crystal display (OLED), a cathode ray tube (CRT), and a plasma display panel (PDP). In addition, the display unit 43 is connected to the bus through a video interface, and data transmission between the display unit 43 and the bus may be controlled by the graphic controller.

The inspection apparatus 4 may further include an alarm unit 45 that generates an alarm when the failure determination unit 425 determines that the battery case 13 is defective. When generating an alarm, it is preferable to generate an audible or visual alarm such as lighting of a lamp or a warning sound so that the user can intuitively know.

Each of the components of the vision sensor 41, the control unit 42, the storage unit 44, and the display unit 43 described so far is a task, a class, a subroutine, a process, an object, and an execution performed in a predetermined area on the memory. It may be implemented in software such as threads and programs, or hardware such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), or a combination of the software and hardware. there is. The components may be included in a computer-readable storage medium, or a part thereof may be distributed and distributed among a plurality of computers.

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical functions. It is also possible for the functions recited in blocks to occur out of order in some alternative implementations. For example, two blocks shown one after another may be performed substantially simultaneously, and it is also possible that the blocks are sometimes performed in the reverse order according to a corresponding function.

When the inspection device 4 according to an embodiment of the present invention is used, the punch edge 1611 of the cup part 133 is clearly displayed, so that the inspection device 4 cuts the punch edge 161 of the cup part 133 . It can be automatically set as the reference line ST, and the distance to each component of the battery case 13 can be accurately measured based on the punch edge 1611 of the cup part 133 . For example, the size and position of the degassing unit 137 may be measured, and even after the manufacture of the secondary battery 1 is completed, the cup unit 133 , the electrode lead 12 , the bat ear 15 , and the side 134 . , the size and positions of the folding part 139 and the insulating part 14 can be accurately identified. Accordingly, it is possible to easily determine whether the secondary battery 1 is defective, and even if the secondary battery 1 is mass-produced, its specifications and quality can be efficiently and collectively managed.

In particular, since the position of the electrode lead 12 can be accurately measured, it can be connected when easily connecting the electrode leads 12 to manufacture the battery module 5 . In addition, the position of the cup portion 333 can be accurately measured, so when sequentially stacking or arranging a plurality of secondary batteries 1 in a line to manufacture the battery module 5, the alignment of the plurality of secondary batteries 1 diagram may be improved.

20 is a schematic diagram illustrating a state in which the manufacture of the secondary battery 1 is completed by cutting the degassing unit 137 of the battery case 13 according to an embodiment of the present invention.

After secondary sealing of the battery case 13 to form the sealing part 1341 , the degassing part 137 is cut by setting a cutting line CT on the outside of the sealing part 1341 . Accordingly, as shown in FIG. 20 , the length of the degassing unit 137 may be shortened, and the volume of the secondary battery 1 may be reduced. Through the above process, the manufacture of the pouch-type secondary battery 1 is completed.

On the other hand, in the side 134 remaining after cutting the degassing part 137 , the electrode lead 12 is not formed to protrude among the plurality of sides 134 . However, if the side 134 is left as it is after sealing, the overall volume of the secondary battery 1 increases. Accordingly, to reduce the energy density to volume ratio, it is desirable to fold the side 134 .

Meanwhile, the side 134 may include a sealing part 1341 and an unsealing part 1342 as shown in FIG. 20 . The sealing part 1341 is a region that is located relatively outside and is sealed, and the unsealed part 1342 is a region that is not sealed because it is located relatively inside.

Specifically, when the sealing part 1341 is formed by the secondary sealing of the battery case 13 , the sealing part 1341 is not directly connected to the cup part 133 , but may be formed to be spaced apart to a certain extent. When sealing the side 134 , heat and pressure must be applied to the side 134 using a separate sealing tool (not shown). However, if the side 134 is sealed while the sealing tool is in close contact with the cup part 133 , the sealant layer 1351 located inside the side 134 is partially melted and leaked toward the electrode assembly 10 . , it may contaminate the electrode assembly 10 . In addition, heat from the sealing tool may be transferred to the electrode assembly 10 to damage the electrode assembly 10 . Therefore, sealing the side 134 with the sealing tool spaced apart from the cup part 133 to some extent is desirable. Then, the portion sealed by the sealing tool becomes the sealing portion 1341 , and the portion that is not sealed because the sealing tool is spaced apart from the cup portion 133 becomes the unsealed portion 1342 .

21 is a schematic view showing a state in which the conventional side 334 is folded from the side, and FIG. 22 is a schematic view showing the state in which the conventional side 334 is folded from the top.

Conventionally, when the side 334 is folded, there is a problem in that the side 334 is not fixed and is unfolded again at a predetermined angle. Specifically, as described above, the pouch film 135 is formed by laminating a sealant layer 1351 , a moisture barrier layer 1352 , an extension auxiliary layer 1354 , and a surface protection layer 1353 . Among them, since the sealant layer 1351 includes the first polymer, particularly polypropylene (PP), flexibility and elasticity are great. Therefore, when the side 134 is folded, the restoring force to return to the original state is large. On the other hand, since the moisture barrier layer 1352 is made of a metal, particularly an aluminum alloy, after the side 334 is folded, the limit of elastic deformation is exceeded, and the retention force to maintain the folded state is large.

However, in the conventional pouch film, the moisture barrier layer had a thickness of about 30 to 50 μm, and the sealant layer had a thickness of about 60 to 100 μm. That is, the thickness of the moisture barrier layer was formed to be considerably thinner than the thickness of the sealant layer. Therefore, the restoring force is greater than the retention force, so that the side 334 is not fixed and unfolded again at a predetermined angle. Then, there is a problem in that an unnecessary volume of the secondary battery 3 increases due to the side 334 .

To solve this, as shown in FIGS. 21 and 22 , a tape 38 was separately attached to the side 334 . In particular, the tape 38 was attached together to the side 334 and the outer surface of the bottom 3332 of the cup portion 333, thereby fixing the side 334 to the cup portion 333, preventing it from being unfolded again. Could. However, in this case, as shown in FIG. 21 , there is a problem in that the overall thickness of the secondary battery 3 increases due to the thickness of the tape 38 itself. In addition, after the process of folding the side 334, an additional process of attaching the tape 38 is required, and this process takes a lot of time, increasing the number of processes and lowering the manufacturing yield of the secondary battery 3 There was also a problem.

Meanwhile, when the degassing process is performed, as gas is discharged from the inside of the battery case 13 to the outside, the internal pressure of the cup part 133 is reduced. Conventionally, the electrode assembly 10 is disposed to be spaced apart from the outer wall 338 of the cup part 333 to some extent. Accordingly, in order to reduce the volume of the space 37 between the outer wall 338 of the cup portion 333 and the electrode assembly 10 while the internal pressure of the cup portion 333 is reduced, the outer wall 338 or The bottom portion 3332 could be deformed. In particular, as shown in FIG. 21 , as the outer wall 338 on the side of the folding part of the secondary battery 3 is depressed inward, the punch edge 361 on the side of the folding part 339 of the cup part 333 protrudes to the outside. An edge high phenomenon, in which the height is increased, may occur. Due to this edge-high phenomenon, an unnecessary thickness of the secondary battery 3 is increased, and there is a problem in that the energy density to volume ratio is lowered. In addition, since the outer wall 338 on the side of the folding part 339 of the cup part 333 is deformed, the appearance of the secondary battery 3 is not beautiful, so that there is a problem in that the marketability is also reduced. Furthermore, there was a problem in that the size of the bat ear 15 was further increased and the shape was prominent due to the edge high phenomenon.

23 is a schematic view showing the folded side 134 according to an embodiment of the present invention from the side.

According to an embodiment of the present invention, in the pouch film 135 , since the moisture barrier layer 1352 has a thickness of 50 to 70 μm and the sealant layer 1351 has a thickness of 70 to 100 μm, the pouch film 135 has a thickness of 70 to 100 μm. The thickness of the moisture barrier layer 1352 is further increased. Accordingly, since the retention force is further increased when the side 134 is folded, it is possible to prevent the side 134 from being unfolded again without the need for a separate tape 38 to be attached thereto.

To this end, the secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 10 in which an electrode 101 and a separator 102 are stacked; and a pouch-type battery case 13 having a cup portion 133 for accommodating the electrode assembly 10 therein, wherein the pouch-type battery case 13 includes a side ( 134), and the side 134 includes a sealing portion 1344 that is relatively positioned on the outside and is sealed; and an unsealed portion 1345 that is relatively positioned inside and is not adhered to the cup portion 133 , and is folded in the unsealed portion 1345 .

That is, as shown in FIG. 23 , after the side 134 is folded toward the cup portion 133 in the secondary battery 1 , the side 134 is not adhered to the cup portion 133 while maintaining the folded state. It may not be unfolded. In this case, the side 134 may be folded at an angle of 85° to 95°, in particular, an angle of 88° to 92°. Also, the side 134 may be folded at a position adjacent to the cup portion 133 so that the side 134 may contact the outer wall 138 of the cup portion 133 . In particular, as described above, the side 134 may include a sealing portion 1341 disposed relatively outside and sealed, and an unsealed portion 1342 disposed relatively inside and not sealed. And when the side 134 is folded, it is preferable that the unsealed portion 1342 relatively closer to the cup portion 133 is folded. Thereby, the unnecessary volume of the secondary battery 1 can be further reduced. However, even in this case, the side 134 and the cup portion 133 are not adhered to each other, and the retention force of the side 134 is increased to maintain the folded state.

When the two cup portions 133 are formed on the pouch film 135 , the depth D of the cup portion 133 may be shallower than when one cup portion 133 is formed. This is because, as described above, not only the cup part 133 is intensively stretched, but also the peripheral sides 134 of the cup part 133 are finely stretched as a whole. However, if the width of the side 134 is longer than the depth D of the cup portion 133 , when the side 134 is folded only once, the outer end 1343 of the side 134 is the bottom of the cup portion 133 . It may protrude further outward than (1332).

Therefore, if the two cup parts 133 are formed in the pouch film 135, a double side folding (DSF) method of folding the side 134 twice as shown in FIG. 23 may be used. Specifically, the side 134 may include a first folding part 1344 and a second folding part 1345 . The first folding part 1344 is a folded part at a position relatively closer to the outer end 1343 , and the second folding part 1345 is a part folded at a position relatively closer to the cup part 133 . Accordingly, after the side 134 is first folded based on the first folding part 1344 , the side 134 may be secondarily folded based on the second folding part 1345 . In this case, the first folding part 1344 may be positioned on the sealing part 1341 on the side 134 , and the second folding part 1345 may be positioned on the unsealing part 1342 on the side 134 . there is. In addition, the side 134 may be folded at an angle of 170° to 180°, in particular, an angle of 180° in the first folding unit 1344 . In addition, the second folding unit 1345 may be folded at an angle of 85° to 95°, particularly, 88° to 92°. Thereby, it is possible to prevent the outer end 1343 of the side 134 from protruding further outward than the bottom 1332 of the cup portion 133 .

Meanwhile, according to an embodiment of the present invention, since the electrode assembly 10 may be located very close to the outer wall 138 of the cup portion 133 , an unnecessary volume of the cup portion 133 is reduced. Accordingly, even if the internal pressure of the cup part 133 is reduced by performing the degassing process, it is possible to prevent the outer wall 138 or the bottom part 1332 of the cup part 133 from being deformed. That is, as shown in FIG. 23 , it is possible to prevent the edge high phenomenon from occurring, so that the energy density to volume ratio may not decrease.

24 is a schematic diagram of a battery module 5 according to an embodiment of the present invention.

Since medium and large-sized electronic devices such as automobiles need to have a large output, many secondary batteries 1 are required. In order to easily move and install these secondary batteries 1 , the battery module 5 may be manufactured. When a plurality of secondary batteries 1 are installed in the battery module 5 , electricity can be stably supplied to the outside.

Meanwhile, in order to generate electricity in the electrode assembly 10 of the secondary battery 1 , a chemical reaction between the electrode 101 and the electrolyte occurs, and heat is generated in this process. However, when the ambient temperature is excessively increased due to heat, there is a problem in that a malfunction occurs in the circuit of the electric device in which the secondary battery 1 is installed, or the life of the electric device is shortened. Accordingly, the battery module 5 includes a cooling system for cooling the secondary battery 1 . The cooling system is largely divided into a water cooling type cooling with cooling water and an air cooling type cooling with air. Among them, the water-cooled cooling system has a higher cooling efficiency than the air-cooled cooling system, and thus is used more.

The cooling system includes a cooling plate that directly cools the secondary battery 1 , and a separate flow path is formed inside the cooling plate so that cooling water can flow. In addition, as the thickness of the flow path increases and the length thereof increases, the surface area increases and cooling efficiency may be increased.

In order to manufacture the battery module 5 , first, a plurality of secondary batteries 1 are manufactured, and then these secondary batteries 1 are connected to each other and accommodated in the housing 51 . In this case, the secondary batteries 1 may be arranged in a line and stacked. 24 , when the secondary battery 1 is accommodated in the housing 51 , the long side of the secondary battery 1 faces downward, and a cooling plate (not shown) is provided on the lower surface of the housing 51 . ) can be formed. Accordingly, by cooling the cooling plate from the long side of the secondary battery 1 , it is possible to increase the cooling efficiency.

Meanwhile, a folding part 139 formed by folding the bridge 136 is formed on one side of the secondary battery 1 , and a side 134 , which is a region remaining after the degassing part 137 is cut, is formed on the other side. However, if the cooling plate cools the secondary battery 1 from the side on which the side 134 is formed, the distance between the cooling plate and the electrode assembly 10 increases by the side 134 , so the cooling efficiency is reduced. can be lowered Accordingly, it is preferable to cool the cooling plate from the side where the folding part 139 is formed among the long side surfaces of the secondary battery 1 . To this end, when the rechargeable battery 1 is accommodated in the housing 51 , the folding part 139 may be accommodated in a direction toward the cooling plate, that is, downward.

25 is a front enlarged view showing a state in which the conventional secondary battery 3 is accommodated in the housing 51 of the battery module 5 , and FIG. 26 is a conventional secondary battery 3 in the housing of the battery module 5 . It is an enlarged side view showing the state stored in (51).

As described above, there is a limit in reducing the size of the bat ear 35 in the prior art.

In addition, in the prior art, the angle θ' formed between the folding part 339 and the inner edge 35a of the bat ear 35 was formed to be less than or equal to 151 degrees.

Here, the angle θ ′ is a virtual first line L1 corresponding to the folding part 339 and a virtual second line L2 corresponding to the inner edge 35a of the bat ear 35 . It may mean an angle formed. In particular, the first line L1 and the second line L2 may be determined through image analysis. For example, the first line L1 and the second line L2 may be extracted by connecting a plurality of edge points identified within a region of interest (ROI) in the vision device. Accordingly, even when the folding part 339 or the inner edge 35a of the bat ear 35 is partially bent or bent, the first line L1 and the second line L2 can be clearly defined. Since such image analysis is a well-known technique, a detailed description thereof will be omitted.

Therefore, as shown in FIG. 25 , when the secondary battery 3 is accommodated in the housing 51 , the bat ear 35 provides a large gap d' (eg, between the housing 51 and the folding part 339 ). For example, greater than 1.5 mm). Accordingly, the gap d' may interfere with cooling of the cooling plate, thereby reducing cooling efficiency. To solve this, a heat transfer material 52 is injected into the space between the cooling plate and the folding part 339 of the secondary battery 1 , and the cooling plate cools the folding part 139 through the heat transfer material 52 . made to do

However, if the size of the bat ear 15 is large, the cost increases because a large amount of the heat transfer material 52 must be injected, and since the gap d' between the cooling plate and the folding part 139 is large, the cooling efficiency is still There was a problem with this low.

In addition, when the degassing process is performed through the degassing hole H, as shown in FIG. 26 while the internal pressure of the battery case 33 is reduced, the folding part 339 of the battery case 33 is formed by the electrode assembly. (10) was adhered to. However, there is a limit in reducing the clearance CL' in the prior art, and the width of the folding part 339 is also formed to be large. Accordingly, the space 37 between the outer wall 338 of the cup part 333 and the electrode assembly 10 is formed to be large, and there is a problem in that the energy density relative to the volume of the secondary battery 3 is reduced. Furthermore, since the distance the electrode assembly 10 is separated from the thermal grease 52 also increases, there is a problem in that cooling efficiency is further lowered.

27 is a front enlarged view showing a state in which the secondary battery 1 according to an embodiment of the present invention is accommodated in the housing 51 of the battery module 5, and FIG. 28 is a secondary battery according to an embodiment of the present invention. It is an enlarged side view showing a state in which the battery 1 is accommodated in the housing 51 of the battery module 5 .

The pouch-type secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 10 in which an electrode 101 and a separator 102 are stacked; and a pouch-type battery case 13 having a cup portion 133 accommodating the electrode assembly 10 therein, wherein the battery case 13 includes a first case in which the cup portion 133 is formed in at least one (131) and the second case (132); a folding part 139 for integrally connecting the first case 131 and the second case 132; and a bat ear 15 protruding outward from a portion of both ends of the folding part 139 , wherein the bat ear 15 has a length d of 1.5 mm or less.

Also, the angle θ between the folding part 139 and the inner edge 15a of the bat ear 15 may be formed to be greater than 151 degrees. Also, the angle θ may be 180 degrees or less. And, when the angle θ is 180 degrees, it may mean a state in which the bat ear 15 does not exist.

Here, the angle θ is formed by a virtual first line L1 corresponding to the folding part 139 and a virtual second line L2 corresponding to the inner edge 15a of the bat ear 15 . It can mean angle. For the first line (L1) and the second line (L2), the above description is referred to.

And in the battery module 5 according to an embodiment of the present invention, the electrode assembly 10 formed by stacking the electrode 101 and the separator 102 is a cup portion 133 formed in the pouch-type battery case 13 of the a pouch-type secondary battery (1) housed therein; and a housing 51 in which the secondary battery 1 is accommodated, wherein the battery case 13 includes: a first case 131 and a second case 132 in which the cup part 133 is formed, respectively; a folding part 139 for integrally connecting the first case 131 and the second case 132; and a bat ear 15 protruding outward from a portion of both ends of the folding part 139 , wherein the bat ear 15 has a length d of 1.5 mm or less.

As described above, the bat ear 15 is formed to protrude outward from a portion of both ends of the folding part 139 by folding the bridge 136 . According to an embodiment of the present invention, the length of the bat ear 15 may be 1.5 mm or less, in particular 1 mm or less. The length of the bat-ear 15 may be a length measured from the outer wall 1381 on the side of the folding part 139 to the outermost end of the bat-ear 15 . In this case, as described above, the outer wall 1381 on the side of the folding part 139 may have an inclination angle of 90° to 95° from the bottom part 1332 due to the clearance CL. Considering this, as an example of the bat-ear measurement, the length of the bat-ear 15 is measured from the outermost protruding part of the outer wall 1381 on the side of the folding part 139 to the outermost end of the bat-ear 15. can be length.

The length of the bat ear 15 may be measured in direct contact with the secondary battery 1 using a ruler or vernier calipers, or may be measured in a non-contact manner using a laser displacement sensor or a vision sensor.

In the above, the method for measuring the length of the bat ear is described as an example, and only the case where the method is limited to the above measurement method is not included in the scope of the present invention. The length of the bat-ear may be the length of the bat-ear within the meaning of the present invention as long as it falls within the scope of the claims and the spirit of the present invention.

According to an embodiment of the present invention, the depth (D) of the cup portion 133 is molded to be 6.5 mm or less, the thickness t of the bridge 136 is made thinner, and the punch edge 1611 of the cup portion 133 is formed. The radius of curvature R2 and the clearance CL can be made smaller.

Accordingly, the length d of the bat ear 15 may also be further reduced to 1.5 mm or less, particularly to 1 mm or less. Accordingly, as shown in FIG. 27 , the interval d between the housing 51 and the folding part 139 may be narrowed to 1.5 mm or less. As a result, the thickness of the thermal grease 52 inside the housing 51 may be 1.5 mm or less, and thus the injection amount of the heat transfer material 52 may be further reduced, thereby reducing costs and increasing cooling efficiency. can do.

In addition, as shown in FIG. 28 , the clearance CL can be made smaller and the width FW of the folding part 139 can be made smaller. Accordingly, the space 17 between the outer wall 138 of the cup part 133 and the electrode assembly 10 is reduced, so that the energy density relative to the volume of the secondary battery 1 may increase. In addition, since the distance between the electrode assembly 10 and the thermal grease 52 is also reduced, cooling efficiency may be further increased.

Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and various embodiments derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

1: secondary battery 2: molding device
3: Conventional secondary battery 4: Inspection device
5: battery module 10: electrode assembly
11: electrode tab 12: electrode lead
13: battery case 14: insulation part
15: Bat Year 16: Edge
17: space 21: die
22: punch 33: conventional battery case
35: conventional bat ear 36: conventional edge
37: conventional space 38: conventional tape
41: vision sensor 42: control unit
43: display unit 44: storage unit
45: alarm unit 51: housing
52: thermal grease 101: electrode
102: separator 111: positive electrode tab
112: negative tab 121: positive lead
122: negative lead 131: first case
132: second case 133: cup portion
134: side 135: pouch film
136: bridge 137: degassing unit
138: outer wall 139: folding unit
161: punch edge 162: die edge
163: thickness edge 164: corner
211: forming part 212: bulkhead
213: edge of die 221: edge of punch
333: conventional cup portion 334: conventional side
336: conventional bridge 337: conventional degassing unit
338: conventional outer wall 339: conventional folding part
361: conventional punch edge 362: conventional die edge
421: outline extraction unit 422: image analysis unit
423: reference line setting unit 424: distance calculating unit
425: defective determination unit 1021: peripheral portion
1331: accommodating space 1332: floor
1333: outer wall 1340: temporary sealing part
1341: sealing portion 1342: unsealed portion
1343: outer end 1344: first folding part
1345: second folding unit 1351: sealant layer
1352: moisture barrier layer 1353: surface protective layer
1354: stretching auxiliary layer 1371: edge
1381: bridge side outer wall 1382: degassing unit side outer wall
1391: groove 1611: bridge side punch edge
1612: degassing part side punch edge 1613: first punch edge
1614: second punch edge

Claims (42)

A cup portion for accommodating an electrode assembly formed by stacking electrodes and a separator therein is formed,
The cup part,
Connecting the plurality of outer walls surrounding the periphery and the side or degassing portion, at least one comprising a plurality of die edges formed by rounding with a radius of curvature of 1 mm or less,
The depth of the cup portion,
Pouch-type battery case of 6.5 mm or less. According to claim 1,
The die edge is
At least one pouch-type battery case is formed by being rounded with a radius of curvature of 0.7 mm or less. According to claim 1,
A radius of curvature of the die edge is 1/20 to 1/6 of the depth of the cup part. According to claim 1,
The cup part,
a plurality of punch edges connecting the outer wall and the bottom, respectively, and at least one of which is rounded with a radius of curvature of 1 mm or less; and
A pouch-type battery case further comprising a thickness edge connecting the two adjacent outer walls to each other. 5. The method of claim 4,
A die edge vertical line passing through the boundary between the die edge and the die edge side outer wall and perpendicular to the bottom portion, and an edge vertical line passing through the boundary point between the die edge side punch edge and the die edge side outer wall and perpendicular to the bottom portion A pouch-type battery case with a vertical distance of 0.5 mm or less between them. 5. The method of claim 4,
The thickness edge is,
connected to the two adjacent punch edges to form a corner,
The corner is
At least one pouch-type battery case is rounded and formed with a radius of curvature of 2 mm to 5 mm, and the radius of curvature is greater than the radius of curvature of the thickness edge. 7. The method of claim 6,
The corner is
A pouch-type battery case in which the radius of curvature varies from the inside. 8. The method of claim 7,
The corner is
A pouch-type battery case in which the radius of curvature at the center is larger than the radius of curvature at the periphery. 5. The method of claim 4,
The punch edge is
At least one pouch-type battery case is formed by being rounded with a radius of curvature of 0.7 mm or less. 5. The method of claim 4,
A radius of curvature of the punch edge is 1/20 to 1/6 of the depth of the cup part. According to claim 1,
a first case and a second case each having the cup portion formed thereon; and
Including a bridge formed between the two cup parts,
The bridge is
A pouch-type battery case with a thickness of 2 mm or less. 12. The method of claim 11,
The bridge is
A pouch-type battery case with a thickness of 1.4 mm or less. 12. The method of claim 11,
The bridge is
A pouch-type battery case having a thickness of 1/200 to 1/30 of the width of the electrode assembly. 12. The method of claim 11,
The bridge is
A pouch-type battery case formed by being rounded with a radius of curvature of 1 mm or less. 15. The method of claim 14,
The bridge is
A pouch-type battery case formed by being rounded with a radius of curvature of 0.7 mm or less. 12. The method of claim 11,
The thickness of the bridge is
A pouch-type battery case which is the distance between the bridge and two bridge vertical lines that pass through the boundary points of the bridge-side outer wall, respectively, and are perpendicular to the bottom part. According to claim 1,
The outer wall is
From the bottom, a pouch-type battery case having an inclination angle of 90° to 95°. an electrode assembly formed by stacking an electrode and a separator; and
Including a pouch-type battery case having a cup portion for accommodating the electrode assembly therein,
The battery case,
a first case and a second case in which the cup portion is formed on at least one; and
and a folding unit for integrally connecting the first case and the second case,
The folding part,
1 mm to 3.2 mm wide,
The depth of the cup portion,
A pouch-type secondary battery of 6.5 mm or less. 19. The method of claim 18,
An area of the electrode assembly is 15000mm ² to 100000mm ² A pouch-type secondary battery. 19. The method of claim 18,
The folding part,
A pouch-type secondary battery having a width of 1 mm to 1.6 mm. 19. The method of claim 18,
The folding part,
A pouch-type secondary battery formed including a groove recessed inward. 22. The method of claim 21,
The battery case,
and a pair of protrusions protruding outward with the groove interposed therebetween,
A gap between the innermost portion of the groove and the outermost portion of the protrusion is 0.8 mm or less. 19. The method of claim 18,
The difference between the width of the cup portion and the width of the electrode assembly is,
A pouch-type secondary battery of 2.5 mm or less. 24. The method of claim 23,
The difference between the width of the cup portion and the width of the electrode assembly is,
A pouch-type secondary battery of 1.7 mm or less. 24. The method of claim 23,
The width of the cup portion,
A pouch-type secondary battery that is the distance between the upper ends of the outer walls of both sides of the cup part. 19. The method of claim 18,
The cup part,
a plurality of punch edges respectively connecting the plurality of outer walls and the bottom that surround the periphery, and at least one of which is rounded with a radius of curvature of 1 mm or less;
a plurality of die edges connecting the outer wall and the side or the degassing portion, at least one of which is rounded with a radius of curvature of 1 mm or less; and
A pouch-type secondary battery including a thickness edge connecting two adjacent outer walls to each other. 27. The method of claim 26,
A die edge vertical line passing through the boundary between the die edge and the die edge side outer wall and perpendicular to the bottom portion, and an edge vertical line passing through the boundary point between the die edge side punch edge and the die edge side outer wall and perpendicular to the bottom portion Pouch-type secondary batteries with a vertical distance of 0.5 mm or less between them. 28. The method of claim 27,
The electrode assembly,
A pouch-type secondary battery in which at least one end of the electrode is positioned at a vertical distance of 0.75 mm or less from the vertical edge line. 29. The method of claim 28,
The electrode assembly,
A pouch-type secondary battery in which at least one end of the electrode is positioned at a vertical distance of 0.5 mm or less from the vertical edge line. 27. The method of claim 26,
The separator is
A pouch-type secondary battery in which a peripheral portion protruding outward from the electrode is folded in a direction opposite to the bottom portion with respect to one end of the electrode. 31. The method of claim 30,
The electrode assembly,
The electrode and the separator are each formed in plurality,
The separation membrane accommodated in the cup portion of the first case,
The peripheral portion is folded toward the second case,
The separation membrane accommodated in the cup portion of the second case,
A pouch-type secondary battery in which the peripheral portion is folded toward the first case. 32. The method of claim 31,
The peripheral portion of at least one of the separation membrane,
A pouch-type secondary battery that is aligned with the periphery of the adjacent separator and folded. 27. The method of claim 26,
The punch edge is
A pouch-type secondary battery formed by rounding at least one with a radius of curvature of 0.7 mm or less. 27. The method of claim 26,
A radius of curvature of the punch edge is 1/20 to 1/6 of the depth of the cup part. 27. The method of claim 26,
The die edge is
A pouch-type secondary battery formed by rounding at least one with a radius of curvature of 0.7 mm or less. 27. The method of claim 26,
A radius of curvature of the die edge is 1/20 to 1/6 of a depth of the cup part. 27. The method of claim 26,
The outer wall is
A pouch-type secondary battery having an inclination angle of 90° to 95° from the bottom. 27. The method of claim 26,
The thickness edge is,
connected to the two adjacent punch edges to form a corner,
The corner is
A pouch-type secondary battery, wherein at least one is rounded with a radius of curvature of 2 mm to 5 mm, and the radius of curvature is larger than the radius of curvature of the thickness edge. 39. The method of claim 38,
The corner is
A pouch-type secondary battery in which the radius of curvature changes inside. 40. The method of claim 39,
The corner is
A pouch-type secondary battery in which the radius of curvature at the center is larger than the radius of curvature at the periphery. 19. The method of claim 18,
A pouch-type secondary battery further comprising a bat ear which is formed to protrude 1.5 mm or less outward from both ends of the folding part. 42. The method of claim 41,
An angle between the folding part and the inner edge of the bat ear is greater than 151 degrees.

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