Pouch-type secondary battery and battery module

Abstract

A pouch-type secondary battery according to an embodiment of the present application includes: an electrode assembly in which an electrode and a separator are stacked; a pouch-type battery case including a cup portion configured to internally accommodate the electrode assembly, wherein the battery case includes: a first case and a second case, at least one of which includes the cup portion; a folding portion configured to integrally connect the first case to the second case; and bat ears protruding outward from a portion of both ends of the folding portion, wherein a length of the bat ears is 1.5 mm or less.

Description

TECHNICAL FIELD

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0104227, filed August 19, 2020, and Korean Patent Application No. 10-2021-0074471, filed June 08, 2021, which are incorporated by reference herein in their entirety. TECHNICAL FIELD

[0004] The present application relates to a soft-pack type secondary battery and a battery module, and more particularly, to a soft-pack type secondary battery capable of improving energy density with respect to volume and having a beautiful appearance and a battery module. BACKGROUND

[0005] Generally, a secondary battery includes a nickel-cadmium battery, a nickel-hydrogen battery, a lithium ion battery, and a lithium ion polymer battery. Such a secondary battery is being applied to small products such as a digital camera, a P-DVD, an MP3P, a mobile phone, a PDA, a portable game device, a power tool, an electric bicycle, etc., and large products requiring high power such as an electric vehicle and a hybrid vehicle, an energy storage device for storing surplus power or renewable energy, and a backup energy storage device.

[0006] Generally, to manufacture a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode. Then, the electrodes are stacked on both sides of a separator to form an electrode assembly. In addition, the electrode assembly is accommodated in a battery case, and then the battery case is sealed after injecting an electrolyte therein.

[0007] According to the material of the case in which the electrode assembly is accommodated, such a secondary battery is classified into a soft-pack type secondary battery and a can type secondary battery. In the soft-pack type secondary battery, the electrode assembly is accommodated in a soft pack made of a flexible polymer material. In addition, in the can type secondary battery, the electrode assembly is accommodated in a case made of a metal or a plastic material.

[0008] The soft pack, as a case of the soft-pack type secondary battery, is manufactured by forming a cup portion through a press process on a flexible pouch film. In addition, when the cup portion is formed, the electrode assembly is accommodated in an accommodation space of the cup portion, and then the side surface of the cup portion is sealed to manufacture the secondary battery.

[0009] In the press processing, the stretch forming is performed by inserting the pouch film into a molding device such as a press and stretching the pouch film by applying pressure to the pouch film using a punch. The pouch film is provided as a plurality of layers, and a moisture barrier layer provided in the pouch film is made of metal. However, according to the prior art, the metal of the moisture barrier layer has a large grain size in an aluminum alloy, and the moisture barrier layer has a thin thickness. Therefore, moldability can be deteriorated. Thus, when a cup portion is molded on the pouch film, it is limited to increase the radius of curvature and the gap of the cup portion edge while molding the cup portion having a deep depth. In addition, the ratio of the volume of the electrode assembly to the volume of the cup portion is small, and it is limited in reducing the size of the bat ear, so that the energy density with respect to the volume of the secondary battery is also reduced. In addition, it is limited to be manufactured as a pointed shape as a whole, and thus, the appearance of the secondary battery is not beautiful, and thus, there is a problem that marketability is also decreased.

[0010] Japanese Patent Registration No. 6022956 exists as a prior art document. SUMMARY

[0011] Technical Problem

[0012] An object to be achieved by the present application is to provide a pouch type secondary battery and a battery module capable of improving the energy density with respect to the volume, having a beautiful appearance, and improving marketability.

[0013] The object of the present application is not limited to the above-mentioned object, but other objects not described herein will be clearly understood by those skilled in the art through the following description.

[0014] Technical Solution

[0015] To achieve the above object, a pouch type secondary battery according to one embodiment of the present application includes: an electrode assembly in which an electrode and a separator are stacked; a pouch type battery case including a cup portion configured to internally accommodate the electrode assembly, wherein the battery case includes: a first case and a second case, at least one of which includes the cup portion; a folding portion configured to integrally connect the first case to the second case; and a bat ear protruding outward from a portion of each of both ends of the folding portion, wherein a length of the bat ear is 1.5 mm or less.

[0016] In addition, a length of an outermost end of the bat ear from a folding portion side outer wall can be 1.5 mm or less.

[0017] In addition, an angle between the folding portion and an inner edge of the bat ear can be greater than 151 degrees.

[0018] In addition, the folding portion can include a groove recessed inward.

[0019] In addition, the battery casing may include a pair of protrusions that project outward and have a groove therebetween, and the distance between the innermost part of the groove and the outermost part of the protrusion may be less than 0.8 mm.

[0020] In addition, the cup portion may include a plurality of punch edges, which will be configured to be connected to the bottom by a plurality of outer walls around their periphery, and at least one punch edge may be rounded.

[0021] Furthermore, the edge of the punch may have a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth of the cup portion.

[0022] In addition, the cup portion may also include a thickness edge configured to connect two adjacent outer walls, wherein the thickness edge may be connected to two adjacent punch edges to form a corner.

[0023] Furthermore, at least one corner may be rounded, and the radius of curvature of the corner may be equal to or greater than the radius of curvature of at least one of the punch edge or the thickness edge.

[0024] Furthermore, both the first and second housings may include a cup portion, and the pouch battery housing may include a bridging portion formed between the two cup portions.

[0025] The bridging portion is rounded.

[0026] In addition, the depth of the cup portion can be 6.5 mm or more.

[0027] Furthermore, the surface area of ​​the electrode assembly can be 15000 mm². 2 Up to 100,000 mm 2 .

[0028] Furthermore, the battery casing can be manufactured by molding a flexible film, and the flexible film may include: a sealant layer made of a first polymer and formed in the innermost layer; a surface protective layer made of a second polymer and formed in the outermost layer; and a moisture barrier layer stacked between the surface protective layer and the sealant layer, wherein the moisture barrier layer may be formed as an aluminum alloy film with a thickness of 50 μm to 80 μm and a particle size of 10 μm to 13 μm, and the sealant layer may have a thickness of 60 μm to 100 μm.

[0029] In addition, the aluminum alloy film may include AA8021 aluminum alloy.

[0030] In addition, the aluminum alloy film may contain 1.3% to 1.7% iron and less than 0.2% silicon.

[0031] Further, the thickness of the moisture barrier layer can be 55 to 65 μm, and

[0032] The thickness of the sealing agent layer is 75 to 85 μm.

[0033] Further, the pouch-type battery case can further include a stretch assisting layer made of a third polymer and stacked between the surface protection layer and the moisture barrier layer.

[0034] Further, the thickness of the stretch assisting layer can be 20 to 50 μm.

[0035] To achieve the above object, a pouch-type secondary battery according to an embodiment of the present application includes: an electrode assembly in which an electrode and a separator are stacked; a pouch-type battery case including a cup portion configured to internally accommodate the electrode assembly, wherein the battery case includes: a first case and a second case, at least one of which includes the cup portion; a folding portion configured to integrally connect the first case to the second case; and a bat ear protruding outward from a portion of each of both ends of the folding portion, wherein an angle between the folding portion and an inner edge of the bat ear is greater than 151 degrees.

[0036] To achieve the above object, a battery module according to an embodiment of the present application includes: an electrode assembly in which an electrode and a separator are stacked; a pouch-type secondary battery accommodated in a cup portion formed in a pouch-type battery case; and a housing in which the secondary battery is accommodated, wherein the battery case includes: a first case and a second case, at least one of which includes the cup portion; a folding portion configured to integrally connect the first case to the second case; and a bat ear protruding outward from a portion of each of both ends of the folding portion, wherein a length of the bat ear is 1.5 mm or less.

[0037] Further, the angle between the folding portion and the inner edge of the bat ear can be greater than 151 degrees.

[0038] Further, the housing can include a cooling plate configured to cool the secondary battery.

[0039] Further, the battery module can further include a heat transfer material formed between the cooling plate and the folding portion of the secondary battery.

[0040] Further, the thickness of the heat transfer material within the housing can be 1 mm or less.

[0041] To achieve the above object, a battery module according to one embodiment of the present application includes: an electrode assembly in which an electrode and a separator are stacked; a pouch-type secondary battery accommodated in a cup portion formed in a pouch-type battery case; and a housing in which the secondary battery is accommodated, wherein the battery case includes: a first case and a second case, at least one of which includes the cup portion; a folding portion configured to integrally connect the first case to the second case; and bat ears protruding outward from a portion of each of both ends of the folding portion, wherein an angle between the folding portion and an inner edge of the bat ears is greater than 151 degrees.

[0042] Further details of the embodiments are included in the detailed description and the accompanying drawings.

[0043] Advantages

[0044] According to the embodiments of the present application, at least the following effects are obtained.

[0045] Since the size of the bat ears can be reduced, the energy density with respect to the volume of the secondary battery can be increased.

[0046] Further, since the space between the outer wall of the cup portion and the electrode assembly is reduced, the energy density with respect to the volume of the secondary battery can be increased.

[0047] Further, since the distance between the electrode assembly and the thermal grease is also shortened, the cooling efficiency can be further improved.

[0048] Further, since the pouch-type battery case and the pouch-type secondary battery each have a pointed shape as a whole, the appearance of the secondary battery can be beautiful, and marketability can be improved.

[0049] The effects of the present application are not limited to the above-described description, and thus more various effects are involved in the present specification. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is an assembled view of a secondary battery 1 according to one embodiment of the present application;

[0051] Figure 2 is a cross-sectional view of a pouch film 135 according to one embodiment of the present application;

[0052] Figure 3 is a graph showing the contents of iron and silicon of an aluminum alloy having an alloy number AA8079 and an aluminum alloy having an alloy number AA8021;

[0053] Figure 4 is a graph showing the tensile strength, elongation, and particle size according to the contents of iron and silicon of an aluminum alloy having an alloy number AA8079 and an aluminum alloy having an alloy number AA8021.

[0054] Figure 5 These are magnified SEM images of the grains of aluminum alloys with alloy number AA8079 and AA8021.

[0055] Figure 6 This is a schematic diagram of a molding device 2 according to one embodiment of the present invention.

[0056] Figure 7 This is an enlarged schematic diagram of the cup portion 333 and the bridging portion 336 based on the prior art.

[0057] Figure 8 This is an enlarged schematic diagram of the cup portion 333 and the bridging portion 336 according to one embodiment of the present invention.

[0058] Figure 9 This is an enlarged schematic diagram of the cup portion 133 and the degassing portion 137 according to one embodiment of the present invention.

[0059] Figure 10 This is a schematic top view showing the state in which the electrode assembly 10 is housed in the cup portion 133 according to an embodiment of the present invention.

[0060] Figure 11 This is a schematic diagram of corner 364 based on existing technology.

[0061] Figure 12 This is a schematic diagram of corner 164 according to one embodiment of the present invention.

[0062] Figure 13 This is a schematic diagram showing the folded state of the battery casing 13 according to one embodiment of the present invention.

[0063] Figure 14 This is a schematic diagram showing the folded state of the battery casing 13 according to one embodiment of the present invention.

[0064] Figure 15 This is an enlarged view of a groove 1391 formed in a battery casing 13 according to an embodiment of the present invention.

[0065] Figure 16 This is an enlarged schematic diagram of the cup portion 133 and the molded edge 1621 according to another embodiment of the present invention.

[0066] Figure 17 This is a schematic diagram showing the folded state of the battery casing 13a according to another embodiment of the present invention.

[0067] Figure 18 This is a schematic diagram showing the folded state of the battery casing 13a according to another embodiment of the present invention.

[0068] Figure 19 is an enlarged view of the recess 1391a formed in the battery case 13 according to another embodiment of the present application.

[0069] Figure 20 is a schematic top view showing a state before the degassing portion 337 of the battery case 33 according to the prior art is cut.

[0070] Figure 21 is a schematic top view showing a state before the degassing portion 137 of the battery case 13 according to one embodiment of the present application is cut.

[0071] Figure 22 is a block diagram of the inspection device 4 according to one embodiment of the present application.

[0072] Figure 23 is a schematic view showing a state where the degassing portion of the battery case 13 is cut to complete the manufacture of the secondary battery 1 according to one embodiment of the present application.

[0073] Figure 24 is a schematic side view showing a state where the side surface 334 is folded according to the prior art.

[0074] Figure 25 is a schematic top view showing a state where the side surface 334 is folded according to the prior art.

[0075] Figure 26 is a schematic side view showing a state where the side surface 134 is folded according to one embodiment of the present application.

[0076] Figure 27 is a schematic view of the battery module 5 according to one embodiment of the present application.

[0077] Figure 28 is an enlarged front view showing a state where the secondary battery 3 is accommodated in the case 51 of the battery module 5 according to the prior art.

[0078] Figure 29 is an enlarged side view showing a state where the secondary battery 3 is accommodated in the case 51 of the battery module 5 according to the prior art.

[0079] Figure 30 is an enlarged front view showing a state where the secondary battery 1 is accommodated in the case 51 of the battery module according to one embodiment of the present application.

[0080] Figure 31 is an enlarged side view showing a state where the secondary battery 1 is accommodated in the case 51 of the battery module according to one embodiment of the present application. DETAILED DESCRIPTION

[0081] The advantages and features of the present application and methods of accomplishing the same will be described by referring to the accompanying drawings. The present application may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. Also, the application will only be defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0082] Unless the terms used in the present application are defined differently, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Also, unless specifically defined in the specification, terms defined in commonly used dictionaries are not ideally or excessively interpreted as having formal meanings.

[0083] In the following description, the technical terms are used only to explain specific exemplary embodiments while not limiting the present application. In the present specification, unless specifically mentioned, the singular form of the term can also include the plural form. The meaning of "include" and / or "comprise" does not exclude the presence of additional components.

[0084] Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

[0085] Figure 1 is an assembly view of a secondary battery 1 according to an embodiment of the present application.

[0086] According to an embodiment of the present application, since the tensile strength and the tensile rate of the pouch film 135 can be improved, when the pouch film 135 is molded to manufacture the pouch-type battery case 13, the toughness can be improved to improve the mold pressing performance.

[0087] To this end, the pouch film 135 according to an embodiment of the present application includes a sealant layer 1351 (see Figure 2 ) made of a first polymer and formed at the innermost layer, a surface protection layer 1353 (see Figure 2 ) made of a second polymer and formed at the outermost layer, and a moisture (or gas) barrier layer 1352 (see Figure 2 ) stacked between the surface protection layer 1353 and the sealant layer 1351. The moisture barrier layer 1352 can be formed as an aluminum alloy thin film having a thickness of 50 to 80 μm and a particle size of 10 to 13 μm, and the thickness of the sealant layer 1351 can be 60 to 100 μm. In particular, the thickness of the moisture barrier layer 1352 can be 55 to 65 μm, and the thickness of the sealant layer 1351 can be 75 to 85 μm.

[0088] The electrode assembly 10 is formed by alternately stacking the electrodes 101 (see Figure 8 ) and the separators 102 (see Figure 8 ). First, a slurry in which an electrode active material, a binder, and a plasticizer are mixed with each other is applied to a positive electrode current collector and a negative electrode current collector to manufacture the electrodes 101, such as positive and negative electrodes. Then, the respective 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 an electrolyte is injected to seal the battery case 13.

[0089] The surface area of the electrode assembly 10 can be 15000 mm 2 to 100000 mm 2 , obtained by multiplying the full length by the full width. In particular, the full width of the electrode assembly 10 can be 60 mm or more. Further, the thickness of the electrode assembly 10 in the stacking direction can be 6 mm to 20 mm. Thus, the electrode assembly 10 according to one embodiment of the present application can provide a large battery capacity compared to a general small battery.

[0090] Specifically, the electrode assembly 10 includes two types of electrodes 101, such as positive and negative electrodes, and the separators 102 interposed between the electrodes 101 to insulate the electrodes 101 from each other. The electrode assembly 10 can be a jelly-roll type, a stack type, a stack and fold type, etc. The two types of electrodes 101, i.e., the positive and negative electrodes each have a structure in which an active material slurry is applied to an electrode current collector having a metal foil or a metal mesh shape. The active material slurry can generally be formed by stirring a granular active material, a conductor, etc. in a state of adding a solvent. The solvent can be removed in a subsequent process.

[0091] As shown in Figure 1 , the electrode assembly 10 includes electrode tabs 11. The electrode tabs 11 are connected to the positive and negative electrodes of the electrode assembly 10, respectively, to protrude outward from the electrode assembly 10, thereby providing a path for the movement of electrons between the inside and the outside of the electrode assembly 10. The electrode current collector of the electrode assembly 10 is composed of a portion coated with an electrode active material and a distal end thereof, i.e., an uncoated portion, on which the electrode active material is not coated. Further, each of the electrode tabs 11 can be formed by cutting the uncoated portion or by connecting a separate conductive member to the uncoated portion through ultrasonic welding. As shown in Figure 1 , the electrode tabs 11 can protrude in each of different directions of the electrode assembly 10, but are not limited thereto. For example, the electrode tabs can protrude in various directions, e.g., protrude in the same direction parallel to each other from one side.

[0092] In the electrode assembly 10, the electrode lead 12 that supplies power to the outside of the secondary battery 1 is connected to the electrode tab 11 by spot welding. Further, a portion of the electrode lead 12 is surrounded by the insulating portion 14. The insulating portion 14 can be disposed so as to be limited to the side surface 134 at which the first case 131 and the second case 132 of the battery case 13 are heat-fused, to cause the electrode lead 12 to be joined to the battery case 13. Further, it is possible to prevent electricity generated from the electrode assembly 10 from flowing to the battery case 13 through the electrode lead 12, and it is possible to maintain the battery case 13 sealed. Therefore, the insulating portion 14 can be made of a non-conductor that has no electric conductivity, i.e., is not electrically conductive. In general, although an insulating tape that is easy to adhere to the electrode lead 12 and has a relatively thin thickness is mainly used as the insulating portion 14, the present application is not limited thereto. For example, various members can be used as the insulating portion 14, as long as these members can insulate the electrode lead 12.

[0093] One end of the electrode lead 12 is connected to the electrode tab 11, and the other end of the electrode lead 12 protrudes to the outside of the battery case 13. That is, the electrode lead 12 includes the positive electrode lead 121 whose one end is connected to the positive electrode tab 111 so as to extend in a direction in which the positive electrode tab 111 protrudes, and the negative electrode lead 122 whose one end is connected to the negative electrode tab 112 so as to extend in a direction in which the negative electrode tab 112 protrudes. On the other hand, as shown, the other ends of the positive electrode lead 121 and the negative electrode lead 122 all protrude to the outside of the battery case 13. As a result, electricity generated in the electrode assembly 10 can be supplied to the outside. Further, since the positive electrode tab 111 and the negative electrode tab 112 are each formed so as to protrude in different directions, the positive electrode lead 121 and the negative electrode lead 122 can each extend in different directions. Figure 1

[0094] The positive electrode lead 121 and the negative electrode lead 122 can be made of materials different from each other. That is, the positive electrode lead 121 can be made of the same material as the positive electrode current collector, i.e., an aluminum (Al) material, and the negative electrode lead 122 can be made of the same material as the negative electrode current collector, i.e., a copper (Cu) material or a copper material coated with nickel (Ni). Further, a portion of the electrode lead 12 that protrudes to the outside of the battery case 13 can be provided as a terminal portion and electrically connected to an external terminal.

[0095] The battery case 13 is a pouch that is manufactured by molding a flexible material and accommodates the electrode assembly 10 therein. Hereinafter, a case in which the battery case 13 is a pouch will be described. When a pouch film 135 having flexibility is stretch-formed by using a punch 22 (see Figure 6 ), etc., a portion of the pouch film 135 is stretched to form a cup portion 133 including a cup-shaped accommodation space 1331, thereby manufacturing the battery case 13.

[0096] ​The battery housing 13 accommodates the electrode assembly 10, exposing a portion of the electrode leads 12, and is then sealed. Figure 1 As shown, the battery casing 13 includes a first casing 131 and a second casing 132. A receiving space 1331, in which a cup portion 133 is formed to receive the electrode assembly 10, can be provided in the first casing 131, and the second casing 132 can cover the upper part of the receiving space 1331, so that the electrode assembly 10 does not detach from the outside of the battery casing 13. Figure 1 As shown, one side of the first housing 131 and one side of the second housing 132 can be connected to each other. However, the invention is not limited thereto. For example, the first housing 131 and the second housing 132 can be manufactured separately and are separable from each other.

[0097] When molding the cup portion 133 in the flexible film 135, only one cup portion 133 can be formed in one flexible film 135, but the invention is not limited thereto. For example, two cup portions adjacent to each other can be stretched and formed in one flexible film 135. Then, as Figure 1 As shown, cup portions 133 are formed in the first housing 131 and the second housing 132, respectively. Here, the cup portions 133 formed in the first housing 131 and the second housing 132 may each have the same depth D, but are not limited thereto, and may have different depths D.

[0098] According to one embodiment of the invention, the depth D of the cup portion 133 can be 3 mm or more, especially 6.5 mm or more. Therefore, the cup portion 133 according to one embodiment of the invention can accommodate an electrode assembly 10 with a larger electrode capacity than a conventional small battery.

[0099] After the electrode assembly 10 is received in the receiving space 1331 provided in the cup portion 133 of the first housing 131, the battery housing 13 can be folded relative to the bridging portion 136 formed between the two cup portions 133 in the battery housing 13, so that the two cup portions 133 face each other. Then, the cup portion 133 of the second housing 132 also receives the electrode assembly 10 from above. Therefore, since two cup portions 133 receive one electrode assembly 10, an electrode assembly 10 with a greater thickness can be accommodated compared to the case where only one cup portion 133 is provided. Furthermore, since the first housing 131 and the second housing 132 are integrally connected to each other by folding the battery housing 13, the number of sides 134 that need to be sealed during subsequent sealing processes can be reduced. Therefore, the processing speed can be improved, and the number of sealing processes can be reduced.

[0100] The battery housing 13 may include a cup portion 133 in which a receiving space 1331 for accommodating the electrode assembly 10 is provided, and a degassing portion 137 formed on the side of the cup portion 133 to discharge gas generated in the cup portion 133 through a degassing hole H. When the electrode assembly 10 is accommodated in the cup portion 133 of the battery housing 13, and electrolyte is injected, and then an activation process is performed, gas is generated inside the battery housing 13, and therefore a degassing process is performed to discharge the gas to the outside. A detailed description of the degassing portion 137 will be described later.

[0101] When the electrode lead 12 is connected to the electrode plate 11 of the electrode assembly 10, and an insulating portion 14 is formed on a part of the electrode lead 12, the electrode assembly 10 is housed in a receiving space 1331 provided in the cup portion 133 of the first housing 131, and the second housing 132 covers the receiving space from above. Furthermore, an electrolyte is injected into the receiving space, and the side surfaces 134 extending to the outside of the respective cup portions 133 of the first housing 131 and the second housing 132 are sealed. The electrolyte can move lithium ions generated by the electrochemical reaction of the electrode 101 during the charging and discharging process of the secondary battery 1. The electrolyte may include a non-aqueous organic electrolyte (i.e., a mixture of lithium salt and high-purity organic solvent), or a polymer electrolyte. Furthermore, the electrolyte may include a sulfide-based, oxide-based, or polymer-based solid electrolyte, and the solid electrolyte may have flexibility that allows it to be easily deformed by external forces. The pouch-type secondary battery 1 can be manufactured by the above method.

[0102] Figure 2 This is a cross-sectional view of the soft film 135 according to one embodiment of the present invention;

[0103] According to one embodiment of the present invention, the soft-pack of the battery casing 13 of the pouch-type secondary battery 1 can be manufactured by stretching the soft-pack film 135. That is, the battery casing 13 is manufactured by stretching the soft-pack film 135 using a punch 22 or the like to form a cup portion 133. According to one embodiment of the present invention, as Figure 2 As shown, the flexible film 135 may include a sealant layer 1351, a moisture barrier layer 1352, and a surface protective layer 1353, and may further include a stretching aid layer 1354 if necessary.

[0104] The sealant layer 1351 can be made of a first polymer and formed in the innermost layer to be in direct contact with the electrode assembly 10. Here, the innermost layer means a layer arranged last with respect to the moisture barrier layer 1352 when oriented in the arrangement direction of the electrode assembly 10. When the pouch film 135 having the stacked structure as described above is stretch-formed by using a punch 22 or the like, the battery case 13 can be manufactured while a portion of the stretched pouch film 135 is stretched to form a cup portion 133 including a receiving space 1331 having a pouch-like shape with a mouth. Further, when the electrode assembly 10 is received in the receiving space 1331, an electrolyte is injected. Thereafter, when the first case 131 and the second case 132 are brought into contact with each other so as to face each other, and a heat compression is applied to the side surface 134, the sealant layers 1351 are bonded to each other to seal the pouch. Here, since the sealant layer 1351 is in direct contact with the electrode assembly 10, the sealant layer 1351 must have insulating properties. Further, since the sealant layer 1351 is in contact with the electrolyte, the sealant layer 1351 must have corrosion resistance. Further, since the inside of the battery case 13 is completely sealed to prevent movement of materials between the inside and the outside of the battery case 13, high sealing properties must be achieved. That is, the side surface 134 in which the sealant layers 1351 are bonded to each other should have excellent heat bonding strength. In general, the first polymer forming the sealant layer 1351 can include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, an acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly-p-phenylene-benzobisoxazole, polyarylate, polytetrafluoroethylene, and glass fiber. In particular, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) is used for the sealant layer 1351. The polypropylene (PP) is excellent in mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, and heat resistance, and chemical properties such as corrosion resistance, and thus is mainly used for manufacturing the sealant layer 1351. Further, the sealant layer 1351 can be made of a cast polypropylene, an acid-modified polypropylene, or a polypropylene-butylene-ethylene terpolymer. Here, the acid-treated polypropylene can be a maleic anhydride polypropylene (MAHPP). Further, the sealant layer 1351 can have a single layer structure made of one material or a composite layer structure in which two or more materials respectively form layers.

[0105] According to one embodiment of the present application, the sealant layer 1351 can have a thickness of 60 to 100 μm, particularly 75 to 85 μm. If the thickness of the sealant layer 1351 is less than 60 μm, there is a problem in durability of the sealant layer 1351, for example, in the case of internal breakage during the sealing process. Further, if the thickness of the sealant layer 1351 is thicker than 100 μm, the moldability is deteriorated due to the entire pouch being too thick, or the energy density with respect to the volume of the secondary battery 1 is reduced. When the thickness of the sealant layer 1351 is thin, the insulation breakdown voltage of the pouch film 135 is reduced, and thus the insulation property is deteriorated. When a battery is manufactured using the pouch film 135 having poor insulation property, the defect rate is increased.

[0106] The moisture barrier layer 1352 is laminated between the surface protection layer 1353 and the sealant layer 1351 to secure the mechanical strength of the pouch, to prevent the introduction and discharge of gas or moisture from the outside of the secondary battery 1, and to prevent the leakage of the electrolyte. The moisture barrier layer 1352 can be made of an aluminum alloy thin film. The aluminum alloy thin film can secure the mechanical strength above a predetermined level, but is light in weight. Thus, the aluminum alloy thin film can complement the electrochemical properties of the electrode assembly 10 and the electrolyte and secure heat dissipation.

[0107] More specifically, the aluminum alloy thin film according to one embodiment of the present application can have a particle size of 10 to 13 μm, preferably 10.5 to 12.5 μm, more preferably 11 to 12 μm. When the particle size of the aluminum alloy thin film satisfies the above range, the molding depth can be increased without the generation of pinholes or cracks at the time of cup molding.

[0108] The aluminum alloy thin film can further include one or two or more selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), and zinc (Zn), in addition to aluminum.

[0109] According to the related art, the thickness of the moisture barrier layer 1352 is about 30 to about 50 μm, particularly 40 μm, and thus the moldability is deteriorated. Thus, even when the pouch film is stretch-molded, the depth D' of the cup portion 333 (see Figure 7 ) is deepened, and thus the outer wall 338 (see Figure 7 ) of the cup portion 333 is formed to be similar to a vertical state. Further, there is a limitation in reducing the radius of curvature of the edge 36 (see Figure 7 ) of the cup portion 333. Further, when the battery case is impacted from the outside, the internal electrode assembly is easily damaged due to weak puncture strength.

[0110] To solve this problem, if the thickness of the moisture barrier layer 1352 is increased to about 80 μm or more, not only the manufacturing cost increases, but also the total thickness of the pouch becomes too thick. As a result, there is a problem that the energy density with respect to the volume of the secondary battery 1 deteriorates. If the thickness of the sealant layer 1351 is reduced to less than 60 μm to reduce the total thickness of the pouch, there is a problem that the sealing durability deteriorates as described above.

[0111] According to one embodiment of the present application, the thickness of the moisture barrier layer 1352 can be 50 μm to 80 μm, particularly 55 μm to 65 μm. Thus, the moldability of the moisture barrier layer 1352 can be improved, and when the pouch film 135 is stretch-formed, the depth D of the cup portion 133 can be formed deep, and the outer wall 138 of the cup portion 133 can be formed similar to a vertical state, and thus the radius of curvature R2 of the edge 16 (see FIG. 6) of the cup portion 133 can be reduced. Thus, since the volume of the accommodation space 1331 increases, the volume of the electrode assembly 10 accommodated in the accommodation space 1331 can also increase, and the energy efficiency compared to the volume of the secondary battery 1 can also increase. Furthermore, the manufacturing cost does not significantly increase, the total thickness of the pouch does not significantly increase without reducing the thickness of the sealant layer 1351, and the sealing durability does not deteriorate. Figure 8 ) of the cup portion 133 can be reduced. Thus, since the volume of the accommodation space 1331 increases, the volume of the electrode assembly 10 accommodated in the accommodation space 1331 can also increase, and the energy efficiency compared to the volume of the secondary battery 1 can also increase. Furthermore, the manufacturing cost does not significantly increase, the total thickness of the pouch does not significantly increase without reducing the thickness of the sealant layer 1351, and the sealing durability does not deteriorate.

[0112] Furthermore, since the impact strength of the pouch film is improved, even if the pouch film is damaged by a great pressure from the outside or is pierced by a sharp object, the electrode assembly 10 in the pouch film can be more effectively protected. Here, the excellent impact strength can mean a high strength when a hole is punched in the pouch film 135.

[0113] However, when only the thickness of the aluminum alloy thin film is increased, the forming depth increases, but a pinhole or a crack can be generated in the aluminum alloy thin film after forming, thereby deteriorating the sealing durability.

[0114] As a result of repeated research by the present inventors, when an aluminum alloy thin film having a specific particle size is applied as a material of the moisture barrier layer, and the thickness of the moisture barrier layer and the sealant layer is each controlled within a specific range, it was found that the cup portion is deep-formed, and the sealing durability also remains excellent. Thus, the present application is achieved.

[0115] In particular, the moisture barrier layer 1352 according to the present application includes an aluminum alloy thin film having a particle size of 10 to 13 μm, preferably 10.5 to 12.5 μm, and more preferably 11 to 12 μm. When the particle size of the aluminum alloy thin film satisfies the above range, the molding depth can be increased without generating pinholes or cracks at the time of cup molding. When the particle size of the aluminum alloy thin film exceeds 13 μm, the strength of the aluminum alloy thin film decreases, and the generation of cracks or pinholes increases due to difficulty in dispersing internal stress during stretching. When the particle size is less than 10 μm, the flexibility of the aluminum alloy thin film decreases, and improvement in moldability is limited.

[0116] The particle size varies depending on the composition of the aluminum alloy thin film and the processing method of the aluminum alloy thin film. Here, a scanning electron microscope (SEM) can be used to observe and measure the cross section in the thickness direction of the aluminum alloy thin film. In particular, in the present application, the cross section in the thickness direction of the aluminum alloy thin film can be obtained using a scanning electron microscope, and then the maximum diameter of a predetermined number of grains observed through the SEM image can be measured to evaluate the average of the maximum diameters as the particle size.

[0117] The surface protection layer 1353 is made of a second polymer and is formed in the outermost layer to protect the secondary battery 1 from external friction and impact, and also to electrically insulate the electrode assembly 10 from the outside. Here, the outermost layer means a layer that is arranged last when oriented in the direction opposite to the arrangement direction of the electrode assembly 10 with respect to the moisture barrier layer 1352. The second polymer forming the surface protection layer 1353 can include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, an acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly-p-phenylene-benzobisoxazole, polyarylate, polytetrafluoroethylene, and glass fiber. In particular, a polymer such as polyethylene terephthalate (PET) having wear resistance and heat resistance can be mainly used. In addition, the surface protection layer 1353 can have a single layer structure made of one material or a composite layer structure in which two or more materials are formed as layers, respectively.

[0118] According to one embodiment of the present application, the thickness of the surface protection layer 1353 can be 5 to 25 μm, and particularly 7 to 12 μm. If the thickness of the surface protection layer 1352 is less than 5 μm, there can be a problem of external insulation deterioration. On the other hand, if the thickness of the surface protection layer 1352 is greater than 25 μm, the entire pouch is thicker, and thus the energy density with respect to the volume of the secondary battery 1 can decrease.

[0119] Although PET is inexpensive, has excellent durability, and has excellent electrical insulation, the adhesion of PET to aluminum, which is commonly used for the moisture barrier layer 1352, is poor, and the behavior of PET when stretched by the application of stress can be different. Accordingly, when the surface protection layer 1353 and the moisture barrier layer 1352 are directly adhered to each other, the surface protection layer 1353 and the moisture barrier layer 1352 can delaminate during the stretch forming process. As a result, the moisture barrier layer 1352 cannot be uniformly stretched, resulting in deterioration of the moldability.

[0120] According to one embodiment of the present application, the battery case 13 can be made of a third polymer, and further includes a stretch assisting layer 1354 laminated between the surface protection layer 1353 and the moisture barrier layer 1352. The stretch assisting layer 1354 can be laminated between the surface protection layer 1353 and the moisture barrier layer 1352 to prevent the surface protection layer 1353 and the moisture barrier layer 1352 from delaminating when the surface protection layer 1353 and the moisture barrier layer 1352 are stretched. The third polymer forming the stretch assisting layer 1354 can include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, an acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly-p-phenylene-benzobisoxazole, polyarylate, polytetrafluoroethylene, and glass fiber. In particular, since a nylon resin easily adheres to the polyethylene terephthalate (PET) of the surface protection layer 1353 and has behavior similar to that of the aluminum alloy of the moisture barrier layer 1352 when stretched, the nylon resin can be used primarily. In addition, the stretch assisting layer 1354 can have a single layer structure made of one material or a composite layer structure in which two or more materials are formed as layers, respectively.

[0121] In the prior art, the thickness of the moisture barrier layer 1352 is about 40㎛, and thus the stretching auxiliary layer 1354 has a significantly thin thickness of about 15㎛. That is, the thickness ratio of the stretching auxiliary layer and the moisture barrier layer is 1:2.67, and the thickness ratio of the moisture barrier layer is relatively high. However, as described above, according to one embodiment of the present application, since the moisture barrier layer 1352 has a thickness of about 50㎛ to about 80㎛, particularly 55㎛ to 65㎛, the moldability of the moisture barrier layer 1352 is improved. Here, in order to also improve the moldability of the stretching auxiliary layer 1354, the stretching auxiliary layer 1354 can have a thickness of 20㎛ to 50㎛, particularly 25㎛ to 38㎛. If the thickness of the stretching auxiliary layer 1354 is less than 20㎛, the stretching auxiliary layer 1354 can not comply with the improved moldability of the moisture barrier layer 1352, and can be damaged in the elongation process. On the other hand, if the thickness of the stretching auxiliary layer 1354 is greater than 50㎛, the total thickness of the pouch becomes thick and thus the volume of the secondary battery 1 increases, thereby deteriorating the energy density. In particular, according to one embodiment of the present application, the thickness ratio of the stretching auxiliary layer 1354 and the moisture barrier layer 1352 can be less than 1:2.5. That is, the thickness ratio of the stretching auxiliary layer 1354 can be more improved when compared to the thickness ratio of the stretching auxiliary layer 1354 according to the prior art. However, when the thickness of the stretching auxiliary layer 1354 is too thick, the total thickness of the pouch becomes thick, and thus the thickness ratio can be greater than 1:1.5 in order to prevent the total thickness of the pouch from being too thick. That is, the thickness ratio can be 1:1.5 to 1:2.5.

[0122] Figure 3 FIG. 1 is a graph showing the contents of iron and silicon in an aluminum alloy having an alloy number of AA8079 and an aluminum alloy having an alloy number of AA8021.

[0123] As described above, the aluminum alloy thin film forming the moisture barrier layer 1352 can have a particle size of 10㎛ to 13㎛, preferably 10.5㎛ to 12.5㎛, more preferably 11㎛ to 12㎛.

[0124] In addition, the iron (Fe) content in the aluminum alloy thin film can be 1.2wt% to 1.7wt%, preferably 1.3wt% to 1.7wt%, more preferably 1.3wt% to 1.45wt%. If the iron (Fe) content in the aluminum alloy thin film is less than 1.2wt%, the strength of the aluminum alloy thin film deteriorates, thereby generating cracks and pinholes in the molding process. If the iron (Fe) content exceeds 1.7wt%, the flexibility of the aluminum alloy thin film deteriorates, resulting in limited improvement in moldability.

[0125] In addition, the silicon (Si) content in the aluminum alloy thin film can be 0.2% by weight or less, preferably 0.05% by weight to 0.2% by weight, and more preferably 0.1% by weight to 0.2% by weight. When the silicon content exceeds 0.2% by weight, the moldability can be deteriorated.

[0126] In particular, the aluminum alloy thin film according to the present application can be an aluminum alloy having an alloy number AA8021.

[0127] On the other hand, an aluminum alloy having an alloy number AA8079 is mainly used for a battery pouch according to the related art. When the aluminum alloy contains a large amount of iron, the mechanical strength is improved, and when the aluminum alloy contains a small amount of iron, the flexibility is improved.

[0128] As shown in FIG. 1, Figure 3 The aluminum alloy having an alloy number AA8079 (hereinafter referred to as AA8079 aluminum alloy) contains 0.6% by weight to 1.2% by weight of iron and 0.3% by weight or less of silicon. In the case of the aluminum alloy having an alloy number AA8079, a small amount of iron is contained, and when the moisture barrier layer 1352 is manufactured using the same, the flexibility can be improved, but the strength is deteriorated, and thus the moldability can be limited.

[0129] On the other hand, as shown in FIG. 2, Figure 3 The AA8021 aluminum alloy can contain 1.2% by weight to 1.7% by weight of iron, particularly 1.3% by weight to 1.7% by weight, and 0.2% by weight or less of silicon. In the case of manufacturing the moisture barrier layer 1352 using the AA8021 aluminum alloy, since a large amount of iron is contained, the tensile strength, the tensile ratio, and the impact strength can be improved.

[0130] On the other hand, when a tensile force is applied to any material, the relationship between the tensile strength and the tensile ratio can be represented by a graph. Here, if the vertical axis of the graph is the tensile strength and the horizontal axis is the tensile ratio, the lower area of the graph is the toughness of the corresponding material. The toughness refers to the degree of toughness of the material against breakage, and the more the toughness increases, the more the material is stretched until the material is broken.

[0131] Therefore, when the AA8021 aluminum alloy is used to manufacture the moisture barrier layer 1352, the tensile strength and the tensile ratio can be improved, and thus the toughness and the moldability can be improved.

[0132] Figure 4 FIG. 3 is a graph showing the tensile strength, the tensile ratio, and the grain size according to the contents of iron and silicon of the AA8079 aluminum alloy and the AA8021 aluminum alloy, Figure 5 FIG. 4 is an enlarged SEM photograph of the grains of the AA8079 aluminum alloy and the AA8021 aluminum alloy.

[0133] As shown in FIG. 1, Figure 4As shown, the tensile strength, the tensile ratio, and the grain size vary according to the iron content of the aluminum alloy. In particular, since the tensile strength and the tensile ratio are proportional to the iron content, the tensile strength and the tensile ratio also increase as the iron content increases. On the other hand, since the grain size is inversely proportional to the iron content, the grain size decreases as the iron content increases.

[0134] The AA8079 aluminum alloy has a large grain size of 13 μm to 21 μm. Thus, there is a problem in that the number of pinholes increases since internal stress is less dispersed when stretched, and the moldability of the battery case 13 deteriorates.

[0135] The AA8021 aluminum alloy has a small grain size of 10 μm to 13 μm. Thus, since internal stress is more dispersed when stretched, the number of pinholes decreases, thereby improving the moldability of the battery case 13.

[0136] The pouch-type secondary battery case 13 manufactured by molding the pouch film 135 having the moisture barrier layer 1352 can have improved moldability such that the depth D of the cup portion 133 can be deeper, the outer wall 138 of the cup portion 133 can be formed similar to a vertical state, and the radius of curvature of the edge 16 of the cup portion 133 can be reduced to accommodate a larger and thicker electrode assembly 10. Thus, the secondary battery 1 manufactured using the battery case 13 can improve the energy efficiency with respect to its volume.

[0137] The total thickness of the pouch film 135 according to the present application can be 160 μm to 200 μm, preferably 180 μm to 200 μm. When the thickness of the pouch film 135 satisfies the above range, the molding depth can be increased while minimizing the reduction of the battery accommodation space and the deterioration of the sealing durability due to the increase in the pouch thickness.

[0138] The pouch film 135 according to the present application has excellent tensile strength and tensile ratio by including an aluminum alloy thin film having a specific thickness and grain size. In particular, the tensile strength measured when stretched at a tensile speed of 50 mm / min after the pouch film 135 according to the present application is cut to a size of 15 mm x 80 mm can be 200 N / 15 mm to 300 N / 15 mm, preferably 210 N / 15 mm to 270 N / 15 mm, more preferably 220 N / 15 mm to 250 N / 15 mm, and the tensile ratio can be 120% to 150%, preferably 120% to 140%, more preferably 120% to 130%. As described above, the pouch film laminate according to the present application has high tensile strength and tensile ratio, thereby increasing the toughness. Thus, when the cup is formed, even if the molding depth is deep, the possibility of cracks is low.

[0139] Further, the pouch laminate according to the present application has excellent impact strength by including the aluminum alloy film having a specific thickness and particle size. Specifically, the pouch laminate according to the present application can have an impact strength of 30 N or more.

[0140] Figure 6 is a schematic view of a molding apparatus 2 according to an embodiment of the present application.

[0141] The molding apparatus 2 for molding the pouch 135 according to an embodiment of the present application includes a mold 21 on which the pouch 135 is placed on a top surface thereof, and a punch 22 disposed above the mold 21 to be lowered to punch the pouch 135. Further, the mold 21 includes a molding portion 211 recessed inward from the top surface, and the punch 22 forms the cup portion 133 by stretch-molding the pouch 135 by inserting the pouch 135 into the molding portion 211.

[0142] When the pouch 135 is molded using the molding apparatus 2 according to an embodiment of the present application, as shown in Figure 6 , the mold 21 has two molding portions 211 adjacent to each other, and a partition wall 212 is formed between the two molding portions 211. When the pouch 135 is stretch-molded by inserting the punch 22 into the two molding portions 211 while stretch-molding the pouch 135, one cup portion can be formed in each of the first and second cases 131 and 132 to correspond to the two molding portions 211, respectively, and as a result, two cup portions 133 are formed in total. Further, a bridge portion 136 can be formed between the two cup portions 133 to correspond to the partition wall 212.

[0143] The bridge portion 136 can serve as a reference portion when the battery case 13 is folded later. When the manufacturing of the secondary battery 1 is completed, the bridge portion 136 can form a folding portion 139 (see Figure 14 ) at one side of the secondary battery 1. Since the folding portion 139 integrally connects the first and second cases 131 and 132 to each other, the number of side surfaces 134 to be sealed can be reduced when the sealing process is performed later. Accordingly, the processing rate can be improved, and the number of sealing processes can be reduced. Here, as the width of the folding portion 139 decreases, the space 17 (see Figure 8 ) between the outer wall 138 (see Figure 8 ) of the cup portion 133 and the electrode assembly 10 can also decrease, and thus, since the entire volume of the secondary battery 1 decreases, the energy density per volume can increase.

[0144] Since the width of the folding portion 139 is equal to the thickness t (see Figure 8) is formed corresponding to the partition wall 212, and thus the thickness t of the bridge portion 136 is proportional to the thickness of the partition wall 212. Accordingly, when the pouch film 135 is formed, the thickness t of the bridge portion 136 can be minimized, and for this, the thickness of the partition wall 212 can be minimized. However, if the partition wall 212 is formed to have an excessively high height in a thin state, the partition wall 212 can be damaged in a stretch forming process. In particular, according to the prior art, the mold has a bottom, but in this case, when the punch 22 is molded to the pouch film 135, gas present in a space between the pouch film 135 and the forming portion 211 is not discharged. Accordingly, recently, the bottom of the mold can be removed so that the gas present in the space between the pouch film 135 and the forming portion 211 is easily discharged, but the height of the partition wall 212 can be excessively high. Accordingly, according to one embodiment of the present application, as shown in Figure 6 , a reinforcing portion 2121 having a thickness greater than the partition wall 212 can be formed at a lower portion of the partition wall 212. The reinforcing portion 2121 can be formed deeper than the depth D of the cup portion 133 to be formed in the battery case 13, and can be formed at a position where the partition wall 212 is not damaged. The exact position of the reinforcing portion 2121 can be determined through experiments according to the thickness of the partition wall 212, the material of the partition wall 212, the pressure of the punch 22, and the depth D of the cup portion 133 to be formed.

[0145] Figure 7 is an enlarged schematic view of the cup portion 333 and the bridge portion 336 according to the prior art.

[0146] As described above, in the prior art, in manufacturing the moisture barrier layer, an aluminum alloy having an alloy number of the AA30XX series is frequently used. In addition, the thickness of the moisture barrier layer is about 30 μm to about 50 μm, and particularly, 40 μm, and the stretch assisting layer has a relatively thin thickness of about 15 μm. Accordingly, since the moldability of the pouch film is not good, even if the battery case and the secondary battery are manufactured, the depth D' of the cup portion 333 is not deep, and thus, there is a limitation in manufacturing the pouch film having an overall pointed shape.

[0147] Specifically, there is a limitation in reducing the radius of curvature of the edge 36 of the cup portion 333 according to the prior art.

[0148] The edge 36 of the cup portion 333 includes a punch edge 361 formed corresponding to the edge 221 (see Figure 6 ) of the punch 22, and a mold edge 362 (see Figure 6 ) formed corresponding to the edge 213 (see Figure 11 ) of the mold 21.

[0149] The punch edge 361 connects the plurality of outer walls 338 each with the bottom 3332 around the cup portion 333. However, if the edge 221 of the punch 22 is not rounded, the edge 221 of the punch 22 is sharp. As a result, when the soft envelope is formed, stress can be concentrated on the punch edge 361 of the cup portion 333, thereby easily causing a crack. Also, the die edge 362 connects the plurality of outer walls 338 each with the side surface 134 or the degassing portion 137. If the pressing edge of the die 21 is not rounded, the pressing edge of the die 21 is sharp. As a result, when the soft envelope is formed, stress is concentrated on the die edge 362 of the cup portion 333, easily causing a crack. Here, the rounding of the die edge means forming a curved surface having a curvature, and the curved surface can have only a uniform curvature, but is not limited thereto. For example, the curved surface can have a non-uniform curvature. In the present specification, the rounding of the punch edge 161, the die edge 162, the bridge portion 136, etc. with a specific curvature means that the punch edge 161, the die edge 162, the bridge portion 136, etc. have not only a specific curvature as a whole, but also only a specific curvature at least partially.

[0150] To solve the above problems, as shown in FIG. 1, the edge 221 of the punch 22 and the edge 213 of the die 21 are rounded to a circular punch edge 361 and a circular die edge 362 of the cup portion 333. As a result, stress concentrated on the punch edge 361 and the die edge 362 of the cup portion 333 can be dispersed to some extent. Figure 7

[0151] However, even if the punch edge 361 and the die edge 362 of the cup portion 333 are formed to be circular, the depth D' of the cup portion 333 manufactured is limited to within 2 to 5 times, particularly 2 to 3.25 times, of the ratio of the respective radii of curvature of the edges 361 and 362.

[0152] Therefore, in order to form the depth D' of the cup portion 333 to be a certain degree of depth, the radius of curvature R2' of the punch edge 361 and the radius of curvature of the die edge 362 must be sufficiently large, and if the depth D' of the cup portion 333 is too deep compared to the radii of curvature of the punch edge 361 and the die edge 362, a crack can occur in the punch edge 361 and the die edge 362.

[0153] Therefore, in the related art, when the depth D' of the cup portion 333 is formed to be sufficiently deep (e.g., 6.5 mm or more), there is a problem in that it is difficult to form the radius of curvature R2' of the punch edge 361 and the radius of curvature of the die edge 362 of the cup portion 333 to be below a certain value (e.g., 2 mm).

[0154] ​Furthermore, when two cup portions 133 are formed, a partition wall 212 must be present in the mold 21 to form the bridge portion 136. However, according to the prior art, the moldability of the soft package film is not excellent, and thus, there is a limit in forming the bridge portion 336 having a thin thickness. That is, if the partition wall 212 is also formed to be below a predetermined thickness to form the bridge portion 336 below the predetermined thickness, a crack occurs in the bridge portion 336 because the partition wall 212 becomes sharp.

[0155] To solve this problem, as shown in FIG. 6, the bridge portion 336 is formed to be circular by rounding the partition wall 212. Thus, the stress concentrated at the bridge portion 336 can be dispersed to some extent. In particular, when the radius of curvature R1' of the bridge portion 336 is constant, the radius of curvature R1' corresponds to half of the thickness t' of the bridge portion 336. For example, when the radius of curvature R1' of the bridge portion 336 is formed to be close to about 1 mm, the thickness t' of the bridge portion 336 is formed to be close to about 2 mm. Figure 7

[0156] However, even if the bridge portion 336 is formed to be circular, if the radius of curvature R1' of the bridge portion 336 is formed to be small, a crack occurs in the bridge portion 336 when the depth D' of the cup portion 333 is formed to be slightly deep. Thus, in the prior art, there is a problem in that it is difficult to form the bridge portion 336 having a thickness t' in a range below a predetermined value (for example, 2 mm) while forming the cup portion 333 to be above a certain depth D' (for example, 6.5 mm).

[0157] Furthermore, since the degree of the gap CL' is also considerable, there is a limit in forming the outer wall 338 of the cup portion 333 to be similar to a vertical state. The gap CL refers to a vertical distance between the inner wall of the molding portion 211 of the mold 21 and the outer wall of the punch 22. In fact, there is a fine dimensional difference as much as the gap CL between the molding portion 211 of the mold 21 and the punch 22. If the gap CL is too small, the distance between the inner wall of the molding portion 211 and the outer wall of the punch 22 is too small. Then, the soft package film 135 cannot be inserted into the molding portion 211, or the soft package film 135 can be damaged due to large friction. On the other hand, if the gap CL is too large, the inclination angle of the outer wall 338 of the cup portion 333 increases, and thus, the space 37 between the outer wall 338 of the cup portion 333 and the electrode assembly 10 increases. Therefore, when the soft package film 135 is molded, it is necessary to provide the gap CL having an appropriate size.

[0158] ​The bridging portion 336 is formed to correspond to the partition wall 212 of the mold 21, and the punch edge 361 is formed to correspond to the edge 221 of the punch 22. Therefore, the gap CL′, as the vertical distance between the inner wall of the forming portion 211 of the mold 21 and the outer wall of the punch 22, can represent the vertical distance between the bridging portion 336 and the punch edge 361 in the battery housing 33.

[0159] Specifically, such as Figure 7 As shown, the bridging vertical line V1′ and the edge vertical line V2′ are virtually illustrated. The bridging vertical line V1′ is a virtual vertical line passing through the boundary point P1′ between the bridging portion 336 and the outer wall 338 on the side of the bridging portion 336 and perpendicular to the bottom 3332. Similarly, the edge vertical line V2′ is a virtual vertical line passing through the boundary point P2′ between the punch edge 361 on the side of the bridging portion 336 and the outer wall 338 on the side of the bridging portion 336 and perpendicular to the bottom 3332. The bridging vertical line V1′ corresponds to the inner wall of the forming portion 211 of the mold 21, especially the inner wall of the partition wall 212, and the edge vertical line V2′ corresponds to the outer wall of the punch 22. Therefore, the vertical distance between the bridging vertical line V1′ and the edge vertical line V2′ corresponds to the gap CL′ appearing in the battery housing 33.

[0160] However, in the prior art, when the gap CL is reduced to less than 0.5 mm, and when the depth D′ of the cup portion 333 is formed to be slightly deeper, cracks are likely to appear in the soft membrane 135.

[0161] As described above, in the prior art, there are limitations to making the gap CL′ smaller and the depth D′ of the cup portion 333 deeper. For example, when the cup portion 333 is molded to a predetermined depth D′ (e.g., 6.5 mm) or greater, the angle between the outer wall 338 of the cup portion 333 and the bottom 3332 is greater than 95°. That is, it is limited to forming the outer wall 338 of the cup portion 333 into a similar vertical state with an angle of less than 95°.

[0162] Furthermore, due to limitations in improving the radius of curvature R2′ of the edge of the cup portion 333, there is also a problem of reduced volume of the electrode assembly 10 housed in the cup portion 333. Specifically, as Figure 7 As shown, in the prior art, because the radius of curvature R2′ of the punch edge 361 of the cup portion 333 is large, when the electrode assembly 10 is positioned too close to the outer wall 338 of the cup portion 333, there is a problem 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 metal electrode 101 is positioned on the punch edge 361 of the cup portion 333, and one end of the electrode 101 is deformed to correspond to the punch edge 361 of the cup portion 333, thereby causing damage.

[0163] To solve this problem, in the related art, when the electrode assembly 10 is accommodated in the cup portion 333, the electrode assembly 10 is accommodated at a distance from the outer wall 338 of the cup portion 333. First, the 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 3332 is indicated by a dotted line, and then, as shown in Figure 7 the electrode assembly 10 is accommodated so that one end of the electrode 101 is disposed outside the reference vertical line V3'. Thus, 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 portion 333 and the electrode assembly 10 is increased, the ratio of the volume of the electrode assembly 10 to the volume of the cup portion 333 is decreased, and thus, there is a problem in that the energy density of the secondary battery 3 with respect to the volume is decreased. In addition, since the volume of the unnecessary space inside the cup portion 333 is increased, there is also a problem in that the electrode assembly 10 moves inside the cup portion 333 before the sealing side surface.

[0164] In addition, in the electrode assembly 10, the electrode 101 has high rigidity not to be easily deformed by an external force, and the separator 102 has high flexibility to be easily deformed by an external force. However, when the adjacent electrodes 101 directly contact each other, a short circuit occurs, and thus, the separator 102 is formed to be larger than the electrode 101 to prevent the short circuit from occurring. Thus, when the electrode assembly 10 is formed, the peripheral portion 1021 in which the separator 102 protrudes outwardly more than the electrode 101 is formed together. However, in the related art, since the electrode assembly 10 is accommodated at a distance from the outer wall 338 of the cup portion 333, all of the peripheral portions 1021 of the separator 102 are irregularly crumpled or folded to expose the electrode 101 to the outside, thereby increasing the possibility of the short circuit from occurring.

[0165] As described above, in the related art, since the moldability of the soft film is not excellent, there is a limitation in increasing the thickness t' of the bridge portion 336, the depth D' of the cup portion 333, the curvature radius R2' of the edge 361 of the cup portion 333, and the gap CL'. In addition, since the ratio of the volume of the electrode assembly 10 to the volume of the cup portion 333 is small, the unnecessary volume in the secondary battery 3 is also large, and the energy density with respect to the volume is also decreased. In addition, since the outer wall 338 of the cup portion 333 is not formed in a state similar to a vertical state, and the curvature radius R2 of the edge 361 of the cup portion 333 is also large, there is a limitation in manufacturing the overall pointed shape. As a result, there is a problem in that the appearance of the secondary battery 3 is not excellent, and the marketability is also decreased.

[0166] Figure 8 is a magnified schematic view of the cup portion 133 and the bridge portion 136 according to an embodiment of the present application, and Figure 9is a magnified schematic view of the cup portion 133 and the degassing portion 137 according to an embodiment of the present application.

[0167] According to an embodiment of the present application, since the moldability of the pouch 135 is improved, the thickness t of the bridge portion 136 is formed to be thinner, the curvature radius R2 of the edge 16 of the cup portion 133 and the gap CL can be formed to be smaller, and the volume of the electrode assembly 10 can be increased. Thus, since unnecessary volume in the secondary battery 1 is also reduced, the energy density with respect to the volume can be increased. Further, since the pouch-type battery case 13 and the pouch-type secondary battery 1 are each integrally manufactured in a pointed shape, the appearance of the secondary battery 1 can be excellent, and marketability can be improved.

[0168] To this end, in the pouch-type battery case 13 according to an embodiment of the present application, the cup portion 133 that accommodates the electrode assembly 10 formed by stacking the electrodes 101 and the separators 102 is formed. However, the cup portion 133 includes a plurality of punch edges 161 that respectively connect the bottom portion 1332 to the plurality of outer walls 138 around the circumference, and at least one punch edge 161 is rounded with a curvature radius corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. If the curvature radius R2 of the punch edge 161 is less than 1 / 20 of the depth D of the cup portion 133, stress is excessively concentrated at the punch edge 161, resulting in a crack. On the other hand, if the curvature radius R2 of the punch edge 161 is greater than 1 / 6 of the depth D of the cup portion 133, a pointed cup portion 133 cannot be formed, and thus the energy density can be reduced.

[0169] Specifically, at least one punch edge 161 can be rounded with a curvature radius of 1 mm or less, and particularly 0.7 mm or less.

[0170] Further, the pouch-type secondary battery can include first and second cases 131 and 132 in which cup portions 133 are respectively formed, and a bridge portion 136 formed between the two cup portions 133, in which the thickness of the bridge portion 136 can be 1 / 200 to 1 / 30 of the width of the electrode assembly 10. If the thickness t of the bridge portion 136 is less than 1 / 200 of the width of the electrode assembly 10, stress is excessively concentrated at the bridge portion 136, and thus a crack can occur. When the thickness t of the bridge portion 136 is greater than 1 / 30 of the width of the electrode assembly 10, the bridge portion 136 does not form a pointed shape, and thus the energy density can be reduced.

[0171] Specifically, the thickness of the bridge portion 136 can be 2 mm or less, and particularly 1.4 mm or less.

[0172] Further, among the plurality of punch edges 161, the bridge 136 side punch edge 1611 connecting the bridge 136 side outer wall 1381 facing the bridge 136 and the bottom 1332 can be formed to be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the punch edge 1611 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

[0173] Further, a vertical distance between a bridge vertical line V1 passing through a boundary point P1 of the bridge 136 and the bridge 136 side outer wall 1381 and being perpendicular to the bottom 1332, and an edge vertical line V2 passing through a boundary point P2 of the bridge 136 side punch edge 1611 and the bridge 136 side outer wall 1381 and being perpendicular to the bottom 1332 can be 0.5 mm or less, particularly 0.35 mm or less.

[0174] The cup portion 133 is formed by mold pressing the soft envelope 135 having flexibility using the punch 22 or the like. The cup portion 133 is surrounded by a plurality of outer walls 138 and the bottom 1332, and a space formed by the outer walls 138 and the bottom 1332 functions as an accommodation space 1331 to accommodate the electrode assembly 10.

[0175] The outer wall 138 of the cup portion 133 surrounds an outer edge of the cup portion 133 to embody the shape of the cup portion 133. The outer wall 138 is formed in plurality around the cup portion 133, is also formed on one side of the bridge 136, is also formed on one side of the degassing portion 137 to be described below, and is also formed on one side of the electrode lead 12. The outer wall 138 has an upper end facing the opening of the cup portion 133 and a lower end facing the bottom 1332.

[0176] As described above, the edge 16 of the cup portion 133 includes a punch edge 161 formed to correspond to the edge 221 of the punch 22 and a mold edge 362 formed to correspond to the edge 213 (see Figure 6 ) of the mold 21. The side surface 134 and the degassing portion 137 are formed outward from the upper end of the outer wall 138, and the mold edge 162 connects the upper end of the outer wall 138 to the side surface 134 or the degassing portion 137. Further, the punch edge 161 connects the lower end of the outer wall 138 to the bottom 1332.

[0177] Since the outer wall 138 of the cup portion 133 is formed in plural, the edge 16 of the cup portion 133 is also formed in plural as many as the number of the outer wall 138. That is, if the cup portion 133 is formed in a rectangular shape, since four outer walls 138 of the cup portion 133 are formed, four punch edges 161 and four die edges 162 are also formed. According to one embodiment of the present application, since the moldability of the soft envelope 135 is improved, at least one of the punch edges 161 of the cup portion 133 is rounded with a curvature radius corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, at least one of the punch edges 161 can be rounded with a curvature radius of 1 mm or less, particularly 0.7 mm or less.

[0178] In particular, according to one embodiment of the present application, two cup portions 133 are formed on one soft envelope 135, and a bridge portion 136 is also formed together between the two cup portions 133. Further, as shown in Figure 8 Among the plurality of punch edges 161, the bridge portion 136 side outer wall 1381 connected to the bridge portion 136 side punch edge 1611 of the bottom portion 1332, which faces the bridge portion 136, can be rounded with a curvature radius corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the bridge portion 136 side punch edge 1611 can be rounded with a curvature radius of 1 mm or less, particularly 0.7 mm or less.

[0179] Further, as shown in Figure 9 Among the plurality of punch edges 161, the die edge 162 side punch edge 1612 connected to the bottom portion 1332, which faces the die edge 162 formed on the degassing portion 137 or the electrode lead 12, can also be rounded with a curvature radius corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. If the curvature radius of the die edge 162 is less than 1 / 20 of the depth D of the cup portion 133, stress is excessively concentrated at the punch edge 162, resulting in a crack. On the other hand, if the curvature radius of the die edge 162 is greater than 1 / 6 of the depth D of the cup portion 133, the upper end of the cup portion 133 does not form a sharp shape, and thus the energy density is reduced.

[0180] Specifically, the die edge 162 side punch edge 1612 can be rounded with a curvature radius of 1 mm or less, particularly 0.7 mm or less. Here, at the boundary points P2 and P4 of the punch edge 161 and the outer wall 138, the slope is preferably continuous.

[0181] To this end, the edge 221 of the punch 22 can also be rounded with a predetermined radius of curvature. Here, the radius of curvature of the edge 221 of the punch 22 can be a value obtained by subtracting the thickness of the soft package 135 itself from the radius of curvature R2 of the punch edge 161. For example, if the thickness of the soft package 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.

[0182] According to one embodiment of the present application, since the moldability of the soft package 135 is improved, even if the depth D of the cup portion 133 is molded to a certain degree, when the soft package 135 is stretch-molded by the punch 22, it is possible to prevent the punch edge 161 of the cup portion 133 from being cracked. For example, even if the cup portion 133 is molded to a depth of 7 mm or more based on the case of molding one cup portion 133, and the cup portion 133 is molded to a depth of 6.5 mm or more based on the case of molding two cup portions 133, and even if the cup portion 133 is molded to a depth of 10 mm or more, it is possible to prevent the punch edge 161 of the cup portion 133 from being cracked.

[0183] Here, based on the residual ratio of the aluminum alloy of the moisture barrier layer 1352, when the residual ratio is 60% or more, the above depth (D) of the cup portion 133 in which a crack can occur is determined as a good product, and when the residual ratio is less than 60%, it is determined as a defect. The residual ratio refers to a ratio of the residual amount of the aluminum alloy of the moisture barrier layer 1352 after being molded to the residual amount before being molded at a specific point of the soft package 135. In fact, in the case where the residual ratio is less than 60%, when the cup portion 133 is stretched and molded on the soft package 135, the frequency of occurrence of a crack at the specific point is high, but when the residual ratio is greater than 60%, no crack occurs.

[0184] In the related art, when the depth D' of the cup portion 333 is formed to be greater than 5 times, particularly 3.25 times, the radius of curvature R2' of the punch edge 361 or the radius of curvature of the die edge 362, the residual ratio is low, and thus, the frequency of occurrence of a crack is high. Hereinafter, the easy occurrence of a crack means that the residual ratio is low, and the frequency of occurrence of a crack is high.

[0185] The outer wall 138 has an upper end facing the opening of the cup portion 133, and the side surface 134 and the degassing portion 137 extend to the outside of the cup portion 133. Here, as described above, the degassing portion 137 is formed to have a predetermined thickness, and the outer wall 138 is formed to have a thickness greater than the thickness of the degassing portion 137. Figure 9As shown, the cup portion 133 can also include a plurality of mold edges 162 connecting the upper end of the outer wall 138 to the side surface 134 or the degassing portion 137. In addition, at least one of the mold edges 162 can also be formed to be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, at least one of the mold edges 162 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. To this end, the edge 213 of the mold 21 can also be rounded with a predetermined radius of curvature. Here, the radius of curvature of the edge 213 of the mold 21 can be a value obtained by subtracting the thickness of the pouch film 135 itself from the radius of curvature of the mold edge 162. 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 mold 21 is 0.5 mm or less, the radius of curvature of the mold edge 162 is 0.7 mm or less.

[0186] In particular, as described above, two cup portions 133 are formed on one pouch film 135, and a bridge portion 136 is also formed together between the two cup portions 133. That is, the pouch-type battery case 13 according to one embodiment of the present application includes a first case 131 and a second case 132 in which cup portions 133 in which the electrode assembly 10 formed by stacking the electrode 101 and the separator 102 is accommodated are respectively formed, and a bridge portion 136 formed between the two cup portions 133. Since the bridge portion 136 is also formed to correspond to the partition wall 212 of the mold 21, the bridge portion 136 can be one of the plurality of mold edges 162.

[0187] Therefore, according to one embodiment of the present application, since the moldability of the pouch film 135 is improved, the thickness t of the bridge portion 136 can be 1 / 200 to 1 / 30 of the width EW of the electrode assembly 10 (see Figure 10 ). Specifically, the thickness t of the bridge portion 136 can be formed to be 2 mm or less, particularly 1.4 mm or less.

[0188] Here, as shown in Figure 8 , the thickness t of the bridge portion 136 is preferably a distance between two boundary points P1 of the bridge portion 136 and the outer wall 1381 on the side of the bridge portion 136. Specifically, preferably, the thickness t corresponds to a distance between two vertical bridge lines V1 passing through the boundary points P1 and perpendicular to the bottom 1332. Therefore, when the bridge portion 136 has a constant radius of curvature, the radius of curvature of the bridge portion 136 can correspond to half of the thickness t. The radius of curvature of the bridge portion 136 can be 1 mm or less, particularly 0.7 mm or less.

[0189] Therefore, the top surface of the partition wall 212 of the molding portion 211 can also be rounded with a predetermined radius of curvature. Here, at the boundary point P1 between the bridging portion 136 and the outer side wall 1381 of the bridging portion 136, the slope is preferably continuous. Here, the radius of curvature of the top surface of the partition wall 212 of the molding portion 211 can be a value obtained by subtracting the thickness of the soft film 135 from the radius of curvature of the bridging portion 136. For example, if the thickness of the soft film 135 is 0.2 mm, then when the radius of curvature of the top surface of the partition wall 212 is 0.5 mm or less, the radius of curvature of the bridging portion 136 is 0.7 mm or less.

[0190] According to one embodiment of the invention, since the moldability of the soft film 135 is improved, the depth D of the cup portion 133 is molded to a certain depth. Therefore, even if the radius of curvature of the edge 213 of the mold 21 is reduced and the thickness of the partition wall 212 is formed to be thin, cracks can be prevented in the mold edge 162 and the bridging portion 136. The bridging portion 136 can have a fan-shaped cross-section, and since the outer wall 138 of the cup portion 133 is formed in a near-vertical state, the cross-section can have a shape closer to a semi-circle.

[0191] Here, even if the cup portion 133 is formed into two cup portions 133, it is possible to prevent cracks from appearing in the bridging portion 136 by forming the cup portion 133 to a depth of 3 mm or more, especially 6.5 mm or more, and even more especially 10 mm or more.

[0192] Furthermore, due to the improved moldability of the soft film 135, the gap CL can be reduced to below 0.5 mm, allowing all the multiple outer walls 138 to be formed in a near-vertical state. For example, as Figure 8 As shown, the outer wall 1381 on the side of the bridging portion 136 in the plurality of outer walls 138 can be formed in a state similar to vertical. That is, the gap CL, which is the vertical distance between the bridging portion vertical line V1 passing through the boundary point P1 of the bridging portion 136 and the outer wall 1381 on the side of the bridging portion 136 and perpendicular to the bottom 1332, and the edge vertical line V2 passing through the boundary point P2 of the bridging portion 136 punch edge 1611 and the outer wall 1381 on the side of the bridging portion 136 and perpendicular to the bottom 1332, can be less than 0.5 mm, especially less than 0.35 mm.

[0193] In addition, such as Figure 9As shown, the mold edge 162 side outer wall 1382 among the plurality of outer walls 138 can also be formed similarly to the vertical state. That is, a vertical distance CL between a mold edge vertical line V4 passing through a boundary point P3 of the mold edge 162 and the mold edge 162 side outer wall 1382 and being perpendicular to the bottom 1332 and a mold edge vertical line V2 passing through a boundary point P4 of the mold edge 162 side punch edge 1612 and the mold edge 162 side outer wall 1382 and being perpendicular to the bottom 1332 can be 0.5 mm or less, particularly 0.35 mm or less.

[0194] Therefore, even based on the case where the cup portion 133 is formed in two, the depth D of the cup portion 133 can be 3 mm or more, particularly 6.5 mm or more, or more particularly 10 mm or more, and the inclination angle between the outer wall 138 of the cup portion 133 and the bottom 1332 can also be 90° to 95° and can also be formed similarly to the vertical state to have an inclination angle of 90° to 93°, and thus, cracks can be prevented from occurring in the battery case 13. Furthermore, since the space between the outer wall 138 of the cup portion 133 and the electrode assembly 10 can also be reduced, the energy density with respect to the volume of the secondary battery 1 can be increased.

[0195] Since the curvature radius R2 of the punch edge 161 of the cup portion 133 is further reduced, even if the electrode assembly 10 is disposed very close to the outer wall 138 of the cup portion 133, the electrode 101 of the electrode assembly 10 can be prevented from being damaged.

[0196] To this end, a method of manufacturing a pouch-type secondary battery 1 according to one embodiment of the present application includes a process of forming an electrode assembly 10 by stacking an electrode 101 and a separator 102, a process of molding a pouch film 135 to form a cup portion 133 to manufacture a pouch-type battery case 13, a process of accommodating the electrode assembly 10 in an accommodation space 1331 of the cup portion 133, and a process of sealing a side surface 134 extending to the outside of the cup portion 133 to manufacture the pouch-type secondary battery 1.

[0197] In particular, in the process of accommodating the electrode assembly 10, a difference between the width CW of the cup portion 133 and the width EW of the electrode assembly 10 can be 2.5 mm or less, particularly 1.7 mm or less. Here, the width EW of the electrode assembly 10 can mean the width of the electrode 101. That is, the peripheral portion 1021 protruding from the separator 102 more than the electrode 101 can be excluded from the calculation of the width EW.

[0198] Furthermore, the electrode assembly 10 can be accommodated such that at least one end of the electrode 101 is disposed at a position having a vertical distance g of 0.75 mm or less, particularly 0.5 mm or less, from a mold edge vertical line V2 passing through a boundary point P2 between the punch edge 161 and the outer wall 138 and being perpendicular to the bottom 1332.

[0199] Specifically, such as Figure 8 and Figure 9 As shown, the edge vertical line V2, which passes through the boundary point P2 of the punch edge 161 and the outer wall 138 and is perpendicular to the bottom 1332, is indicated by a dashed line. Furthermore, at least one end of the electrode 101 is positioned such that the vertical distance g from the edge vertical line V2 is less than 0.75 mm, particularly less than 0.5 mm. More specifically, the reference vertical line V3, which is perpendicular to the bottom 1332 and has a vertical distance g from the edge vertical line V2 of 0.75 mm, particularly 0.5 mm, is indicated by a dashed line. Here, since the radius of curvature R2 of the punch edge 161 can be particularly less than 0.7 mm, the reference vertical line V3 can pass through the curvature center C of the punch edge 161. Furthermore, the electrode assembly 10 is housed such that one end of the electrode 101 is positioned between the edge vertical line V2 and the reference vertical line V3. This can be confirmed by removing the secondary battery 1 itself, but is not limited to this, and can be confirmed by various methods without removing the secondary battery 1, such as computed tomography (CT), magnetic resonance imaging (MRI), X-ray, etc. Therefore, while preventing damage to the electrode 101, the volume ratio of the electrode assembly 10 to the cup portion 133 can be further increased, thus increasing the energy efficiency relative to volume. Furthermore, since unnecessary volume inside the cup portion 133 is reduced, movement of the electrode assembly 10 within the cup portion 133 can be prevented.

[0200] Furthermore, because the electrode assembly 10 is arranged very close to the outer wall 138 of the cup portion 133, the partition 102 will not be disorderly wrinkled or folded. Figure 8 As shown, the peripheral portion 1021 of the partition 102 protruding outward from the electrode 101 is folded in the opposite direction to the bottom 1332 relative to one end of the electrode 101.

[0201] Electrode assembly 10 is formed by stacking electrodes 101 and separators 102, and multiple electrodes 101 and multiple separators 102 can be formed. Battery housing 13 includes a first housing 131 and a second housing 132. If the bridging portion 136 of battery housing 13 is folded to accommodate the upper part of electrode assembly 10 in cup portion 133, the separators 102 accommodated in cup portion 133 of first housing 131 are configured such that peripheral portions 1021 are folded to face the second housing, and the separators 102 accommodated in cup portion 133 of second housing 132 are configured such that peripheral portions 1021 are folded to face the first housing 131. Therefore, the peripheral portions 1021 of separators 102 are aligned and folded sequentially. Furthermore, since separators 102 cover electrodes 101 so as not to expose them to the outside, short circuits can be prevented.

[0202] In more detail, the width of the separators 102 can be wider than the width CW of the cup portion 133 in a state before the electrode assembly 10 is accommodated in the cup portion 133. Thus, when the electrode assembly 10 is accommodated in the cup portion 133, the peripheral portion 1021 of the separators 102 can be folded in a predetermined direction and come into contact with the inner periphery of the cup portion 133.

[0203] The difference between the width CW of the cup portion 133 and the width EW of the electrode assembly 10 can be very small, for example, 2.5 mm or less, particularly 1.7 mm or less. Thus, a process of easily folding the peripheral portion 1021 of the separators 102 while the electrode assembly 10 is accommodated in the cup portion 133 can be required.

[0204] Thus, the process of accommodating the electrode assembly 10 in the accommodation space 1331 of the cup portion 133 can include a process of pressing the electrode assembly 10 into the cup portion 133. Thus, when compared with a conventional method of placing the electrode assembly 10 on the cup portion, the separators 102 can be folded in a certain direction while maintaining a small difference between the width CW of the cup portion 133 and the width EW of the electrode assembly 10 to easily and reliably accommodate the electrode assembly 10 in the accommodation space of the cup portion 133.

[0205] Further, the process of accommodating the electrode assembly 10 in the accommodation space 1331 of the cup portion 133 can further include a process of folding each corner (apex) of the plurality of separators 102 of the electrode assembly 10 before pressing the electrode assembly 10 into the inside of the cup portion 133. In the above process, a separate sealing tool can be used to fold each corner (apex) of the plurality of separators 102 to be gathered in a central portion in a stacking direction of the electrode assembly 10.

[0206] That is, the electrode assembly 10 can be inserted into the cup portion 133 in a state in which the four corners of the separators 102 are previously aligned. Thus, the electrode assembly 10 can be smoothly inserted into the accommodation space 1331 of the cup portion 133. As described above, according to one embodiment of the present application, since the moldability of the soft pouch 135 is improved, the thickness t of the bridge portion 136 is formed to be thinner, the curvature radius R2 of the edge 16 of the cup portion 133 and the gap CL can be formed to be smaller, and the volume of the electrode assembly 10 can be increased. Thus, since the unnecessary volume of the secondary battery 1 is also reduced, the energy density per volume can be increased. Further, since the soft-pouch type battery case 13 and the soft-pouch type secondary battery 1 are each integrally manufactured in a pointed shape, the appearance of the secondary battery 1 can be excellent, and marketability can be improved.

[0207] Figure 10 is a schematic top view showing a state in which the electrode assembly 10 is accommodated in the cup portion 133 according to one embodiment of the present application.

[0208] According to one embodiment of the present application, as described above, since the radius of curvature R2 of the punch edge 161 of the cup portion 133 is further reduced, the electrode assembly 10 is accommodated so that one end of the electrode 101 is disposed between the edge vertical line V2 and the reference vertical line V3. Therefore, even if the electrode assembly 10 is disposed very close to the outer wall 138 of the cup portion 133, the electrode 101 of the electrode assembly 10 can be prevented from being damaged.

[0209] The edge vertical line V2 and the reference vertical line V3 can also be shown on the punch edge 1611 on the side of the bridge portion 136, and can also be shown on the punch edge 1612 on the side of the die edge 162. The vertical distance g between the edge vertical line V2 and the reference vertical line V3 can be 0.75 mm, in particular 0.5 mm.

[0210] Further, if two cup portions 133 are formed in the battery case 13, since the bridge portion 136 is provided, the bridge portion vertical line V1 can be shown on one side of the cup portion 133, and the die edge vertical line V4 can be shown on the other side of the cup portion 133. The vertical distance CL between the bridge portion vertical line V1 and the edge vertical line V2 can 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 can also be 0.5 mm or less, in particular 0.35 mm or less.

[0211] However, if only one cup portion 133 is formed in the battery case 13, the bridge portion is not provided. However, since the die edge 162 is formed on each of the two sides of the cup portion 133, the die edge vertical line V4 can be shown on each of the two sides of the cup portion 133.

[0212] If two cup portions 133 are formed in the battery case 13, the width CW of the cup portion 133 can represent the vertical distance from the bridge portion 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 can represent the vertical distance between the two die edge vertical lines V4.

[0213] Both the bridge portion vertical line V1 and the die edge vertical line V4 pass through the top end of the outer wall 138 of the cup portion 133. Therefore, according to one embodiment of the present application, the width CW of the cup portion 133 can be the vertical distance between the upper ends of the outer walls 138 on the two sides of the cup portion 133. The difference between the width CW of the cup portion 133 and the width EW of the electrode assembly 10 can be 2.5 mm or less, in particular 1.7 mm or less. Further, as described above, the width EW of the electrode assembly 10 can be 60 mm or more.

[0214] The width CW of the cup portion 133 can be obtained by measuring the vertical distance between the upper ends of the outer walls 138 on both sides of the cup portion 133 in the battery case 13. Further, in the secondary battery 1, the position between the upper ends of the outer walls 138 on both sides can be grabbed from the outside of the cup portion 133 using a laser displacement sensor or the like, and then the distance between the two positions can be calculated. Here, when the laser displacement sensor moves from the side surface 134 toward the die edge 162 and the outer wall 138 while irradiating laser light from the outside of the cup portion 133 with the laser displacement sensor to detect a point at which the displacement suddenly changes, the corresponding point can be recognized as the upper end of the outer wall 138. The method of measuring the width CW of the cup portion is described above as an example, and the case where the method is limited only to the above-described measurement method is not included in the scope of the present application. The width CW of the cup portion can be the width CW of the cup portion in the sense of the present application as long as it falls within the scope of the claims and the spirit of the present application.

[0215] Figure 11 is a schematic view of the corner portion 364 according to the related art, Figure 12 is a schematic view of the corner portion 164 according to one embodiment of the present application.

[0216] As Figure 12 shown, the edge 16 of the cup portion 133 further includes a thickness edge 163 connecting two adjacent outer walls 138 of the cup portion 133, and a punch edge 161 and a die edge 162. The thickness edge 163 is formed in the thickness direction of the cup portion 133, and is formed while the jelly-roll 135 is elongated at the same time as the jelly-roll 135 is elongated between the corner portion of the die 21 and the corner portion of the punch 22. Further, at least one of the thickness edges 163 can be rounded.

[0217] The thickness edge 163 has a radius of curvature, which may be the same as, but not limited to, the radius of curvature R2 of the two adjacent punch edges 161, namely the first punch edge 1613 and the second punch edge 1614. For example, the thickness edges may be formed differently. For example, as described above, at least one of the punch edges 161 may be rounded with a radius of curvature of less than 1 mm, particularly less than 0.7 mm, and at least one of the thickness edges 163 may be rounded with a radius of curvature of 0.5 mm to 5 mm, particularly 0.5 mm to 2 mm. According to the prior art, when the thickness edge 363 is formed to be rounded with a radius of curvature of less than 5 mm, particularly less than 2 mm, the problem is that stress is also concentrated on the thickness edge 363 of the cup portion 333, leading to cracks. However, according to one embodiment of the invention, even if the depth D of the cup portion 133 is formed to a certain extent, cracks in the thickness edge 163 of the cup portion 133 can be prevented. Here, one of the first punch edge 1613 and the second punch edge 1614 can be the punch edge 1611 on the bridging portion 136 side, and the other can be the punch edge on the electrode lead 12 side (not shown). Alternatively, one of the two punch edges can be the punch edge 1612 on the mold edge 162 side, and the other can be the punch edge on the electrode lead 12 side (not shown).

[0218] like Figure 12 As shown, the thickness edge 163 connects to two adjacent punch edges 161, namely the first punch edge 1613 and the second punch edge 1614, to form a corner 164. In the prior art, such as Figure 11 As shown, the multiple edges 221 of all the punches 22 are rounded with the same radius of curvature, so the corners (not shown) of the punches 22 naturally become round with the same radius of curvature. Therefore, when the soft film 135 is stretched by molding the soft film 135 with the punches 22, the corners 364 naturally become round with the same radius of curvature as the punch edges 361.

[0219] However, when the flexible membrane 135 is stretched, stress concentration occurs at the corner 364. Specifically, the corner 364 is formed by the intersection of three edges 36, and therefore, the corner 364 can be longer than the punch edge 361 or the thickness edge 363. Consequently, stress can be concentrated at the corner 364 more than at the punch edge 361 or the thickness edge 363. Therefore, excessive stretching of the flexible membrane 135 causes a whitening phenomenon in certain portions, which turns white before cracking occurs, and ultimately makes it prone to cracking.

[0220] Therefore, according to one embodiment of the present invention, such as Figure 12 As shown, at least one of the corners 164 is also round, and the radius of curvature of the corner 164 is greater than or equal to the radius of curvature of at least one of the punch edge 161 and the thickness edge 163.

[0221] In particular, according to one embodiment of the present application, the radius of curvature can vary inside the corner portion 164. That is, the radius of curvature of the central portion 1641 of the corner portion 164 and the radius of curvature of the peripheral portion 1642 of the corner portion 164 can be different from each other. Specifically, the radius of curvature of the central portion 1641 of the corner portion 164 can be greater than the radius of curvature of the peripheral portion 1642 of the corner portion 164. For example, because the peripheral portion 1642 of the first corner portion 164 is adjacent to the first punch edge 132, the second punch edge 134, and the thickness edge 163, the radius of curvature of the peripheral portion 1642 of the first corner portion 164 can be the same as the radius of curvature of at least one of the punch edge 161 and the thickness edge 163. On the other hand, because the central portion 1641 of the first corner portion 164 is spaced apart from the first punch edge 1613, the second punch edge 1614, and the thickness edge 163, the radius of curvature of the central portion 1641 of the first corner portion 164 can be greater than the radius of curvature of at least one of the punch edge 161 and the thickness edge 163. That is, the radius of curvature of the corner portion 164 can be different from the radius of curvature of at least one of the punch edge 161 and the thickness edge 163.

[0222] Accordingly, the radius of curvature of the corner portion 164 can gradually increase from the peripheral portion 1642 of the corner portion 164 to the central portion 1641 of the corner portion 164. Furthermore, because the radius of curvature inside the corner portion 164 is not constant but varies, the central portion 1641 of the corner portion 164 can have a non-spherical shape, rather than an exact spherical shape.

[0223] Unlike the punch edge 161, the radius of curvature of the corner portion 164 and the range to be formed in the cup portion 133 must be clearly set. If the range of the corner portion 164 formed in the cup portion 133 is too narrow, the soft envelope 135 is still excessively elongated, resulting in whitening or cracking. On the other hand, if the range of the corner portion 164 formed in the cup portion 133 is too wide, the space 17 between the outer wall 138 of the cup portion 133 and the electrode assembly 10 is reduced, and thus, the energy density of the secondary battery 1 with respect to its volume can be increased. Accordingly, according to one embodiment of the present application, as shown in FIG. 6, the corner portion 164 can be formed within 2 mm to 3.5 mm from the cup portion 133 in the longitudinal direction lc with respect to the thickness edge 163, within 2 mm to 3.5 mm from the cup portion 133 in the width direction wc with respect to the thickness edge 163, and within 2 mm to 3.5 mm from the cup portion 133 in the thickness direction dc with respect to the punch edge 161. Furthermore, the range in which the corner portion 164 is formed can gradually widen as the depth of the cup portion 133 increases. Figure 12

[0224] Because the corner portion 164 of the cup portion 133 is formed as described above, more stress concentrated in the corner portion 164 can be dispersed to prevent whitening and cracking. ​

[0225] Figure 13 is a view showing a state in which the pouch-type battery case 13 is folded according to an embodiment of the present application, Figure 14 is a view showing a state in which the pouch-type battery case 13 is folded according to an embodiment of the present application.

[0226] When the two cup portions 133 are formed in the soft envelope 135, the cup portions 133 are formed in the first case 131 and the second case 132 of the battery case 13, respectively. As Figure 13 indicated, after the electrode assembly 10 is accommodated in the accommodation space 1331 provided in the cup portion 133 of the first case 131, the bridge portion 136 formed between the two cup portions 133 is folded in the battery case 13 so that the two cup portions 133 face each other. When the bridge portion 136 is folded, the folding portion 139 is formed at one side of the secondary battery 1. Then, an electrolyte can be injected, and the side surface 134 extending to the outside of the cup portions 133 of the first case 131 and the second case 132 can be sealed to manufacture a soft-pack type secondary battery, as Figure 14 indicated.

[0227] The soft-pack type secondary battery 1 according to an embodiment of the present application, which is manufactured as described above, can include an electrode assembly 10 in which electrodes 101 and separators 102 are stacked, and a soft-pack type battery case 13 having a cup portion 133 in which the electrode assembly 10 is accommodated, in which the cup portion 133 includes a plurality of punch edges 161 connecting a plurality of outer walls 138 to a bottom 1332, respectively. At least one of the punch edges 161 can be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of a depth D of the cup portion 133. Specifically, at least one of the punch edges 161 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

[0228] A difference between a width CW of the cup portion 133 and a width EW of the electrode assembly 10 can be 2.5 mm or less, particularly 1.7 mm or less. Further, the electrode assembly 10 can be accommodated so that at least one end of the electrode 101 is disposed at a position at a perpendicular distance g of 0.75 mm or less, particularly 0.5 mm or less from an edge perpendicular line V2 passing through a boundary point P2 between the punch edge 161 and the outer wall 138 and perpendicular to the bottom 1332. Further, the battery case 13 can include a first case 131 and a second case 132 in which the cup portion 133 is formed on at least one of the first case 131 and the second case 132, and a folding portion 139 integrally connecting the first case 131 and the second case 132.

[0229] When the folding battery casing 13 is used to manufacture the secondary battery 1, the bridging portion 136 becomes the folding portion 139. Therefore, in the secondary battery 1, the folding portion 139 connects the first casing 131 to the second casing 132 as a whole. Furthermore, the punch edge 1611 on the bridging portion 136 side becomes the punch edge 1611 on the folding portion 139 side, and the outer wall 1381 on the bridging portion 136 side becomes the outer wall 1381 on the folding portion 139 side.

[0230] Furthermore, among the plurality of punch edges 161, the punch edge 1611 on the fold 139 side, which connects the outer wall 1381 of the fold 139 facing the fold 139 to the bottom 1332, can be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the punch edge 1611 on the fold 139 side can be rounded with a radius of curvature of 1 mm or less, especially 0.7 mm or less. Additionally, the electrode assembly 10 can be accommodated such that at least one end of the electrode 101 is arranged between the edge vertical line V2 and the reference vertical line V3. The edge vertical line V2 passes through the boundary point P2 between the punch edge 161 and the outer wall 138 and is perpendicular to the bottom 1332. The reference vertical line V3 is at a vertical distance g from the edge vertical line V2 of 0.75 mm, especially 0.5 mm or less, and is perpendicular to the bottom 1332. As described above, the reference vertical line V3 can pass through the curvature center C of the punch edge 161.

[0231] Figure 15 This is an enlarged view of a groove 1391 formed in a battery casing 13 according to an embodiment of the present invention.

[0232] According to one embodiment of the present invention, when the secondary battery 1 is manufactured by folding the battery casing 13 as described above, the bridging portion 136 may be in the form of a folded portion 139. Specifically, when the battery casing 13 is folded, the circle of the bridging portion 136 may also unfold to some extent, but the traces of the bridging portion 136 remain on the secondary battery 1, and these traces may become the folded portion 139. Therefore, the bridging portion 136 and the folded portion 139 of the battery casing 13 may correspond to each other.

[0233] For example, such as Figure 15 As shown, when the circular shape of the bridging portion 136 is not fully unfolded like a plane, the folding portion 139 includes an inwardly recessed groove 1391 for the secondary battery 1. In this case, since the curvature of the folding portion 139 is less than that of the bridging portion 136, the folding portion 139 can have a larger radius of curvature.

[0234] Since the bridge portion 136 has a curved surface, and the bridge portion 136 side outer wall 1381 has a flat shape, the deformation amounts are different from each other. Therefore, when the battery case 13 is folded, the bridge portion 136 side outer wall 1381 is deformed more, but the bridge portion 136 is deformed less, only enough to unfold the circular shape to some extent. Then, when the battery case 13 is folded, as shown in FIG. 6, the increase or decrease in the slope change amount is shifted around the boundary point P1. That is, each boundary point P1 becomes an inflection point. Therefore, the folding portion 139 can be formed as a curved surface between the two boundary points P1, that is, the two inflection points. Figure 15

[0235] Furthermore, when the circular shape of the bridge portion 136 is not completely unfolded, the two boundary points P1, that is, the portions corresponding to the two inflection points can protrude outward to form protrusions. That is, the protrusions can be formed as a pair of outwardly protruding protruding portions with the folding portion 139, more specifically, the groove 1391 interposed therebetween.

[0236] Alternatively, even if the circular shape of the bridge portion 136 is completely unfolded like a flat surface, the boundary points P of the bridge portion 136 and the bridge portion 136 side outer wall 1381 are connected to the secondary battery 1 by each of two lines (not shown), and the folding portion 139 is formed as a flat surface between the two lines.

[0237] The folding portion 139 can be visually confirmed from the appearance of the secondary battery 1. And as described above, since the thickness t of the bridge portion 136 is preferably the distance between the two boundary points P1 of the bridge portion 136 and the bridge portion 136 side outer wall 1381, the width FW of the folding portion 139 is the distance between the two boundary points P1. If the circular shape of the bridge portion 136 is not completely unfolded, the width FW of the folding portion 139 is the distance between the two boundary points P1, that is, the two inflection points. Alternatively, if the circular shape of the bridge portion 136 is completely unfolded, the folding portion 139 is the distance between the two boundary points P1, that is, the two lines.

[0238] The width FW of the folding portion 139 is not more than the length of the bridge portion 136, and can be 1 mm to 3.2 mm, especially 1 mm to 1.6 mm. As described above, the width FW of the folding portion 139 can be directly measured using a ruler, but can be measured using a magnifying glass (Lupe), or using a 3D camera or a laser 2D line sensor. That is, the width FW can be measured in various methods without limitation.

[0239] ​According to the prior art, the thickness t' of the bridge portion 336 is formed thick, and the width of the folded portion 339 is also formed large, and thus the space 37 between the outer wall 338 of the cup portion 333 and the electrode assembly 10 is also formed large. However, according to one embodiment of the present application, since the width FW of the folded portion 139 can be reduced, the space 17 between the outer wall 138 of the cup portion 133 and the electrode assembly 10 can also be reduced. Thus, the energy density with respect to the volume of the secondary battery 1 can be increased.

[0240] Further, since the moldability of the soft pack film is low in the prior art, the protrusion is largely protruded outward. However, according to one embodiment of the present application, the protrusion can be less protruded, and the flatness of the folded portion 139 or the outer wall 1381 on the folded portion 139 side can be improved.

[0241] Specifically, the distance p between the innermost portion of the groove 1391 and the outermost portion of the protrusion can be defined as the flatness. In the case of the battery case according to the prior art, the flatness is formed to be 1 mm or more, even 1.5 mm. On the other hand, according to one embodiment of the present application, the flatness p can be formed to be 0.8 mm or less, preferably 0.3 mm or less. Thus, the energy density with respect to the volume of the secondary battery 1 can be further increased.

[0242] Figure 16 is a magnified schematic view of the cup portion 133 and the mold edge 1621 according to another embodiment of the present application.

[0243] According to one embodiment of the present application, two molding portions 211 are formed on the mold 21 to be adjacent to each other, and a partition wall 212 can be formed between the two molding portions 211. Thus, when the soft pack film 135 is molded, two cup portions 133 are formed in one soft pack film 135, and a bridge portion 136 is also formed together between the two cup portions 133. That is, one cup portion 133 is formed in each of the first case 131 and the second case 132.

[0244] However, according to another embodiment of the present application, only one molding portion 211 is formed on the mold 21, and no partition wall is formed. Thus, when the soft pack film 135 is molded, one cup portion 133 is formed in one soft pack film 135, and no bridge portion is formed. That is, the cup portion 133 is formed only in the first case 131.

[0245] According to another embodiment of the present application, at least one of the punch edges 161a of the cup portion 133 is rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, at least one of the punch edges 161a of the cup portion 133 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. As a result, since the moldability of the soft pouch 135 is improved, even if the cup portion 133 is formed to be slightly deep, for example, the depth D is 3 mm or more, particularly 7 mm or more, more particularly 10 mm or more, based on the case where two cup portions 133 are formed, it is possible to prevent cracks from occurring in the punch edges 161a of the cup portion 133.

[0246] Specifically, according to another embodiment of the present application, as shown in FIG. 10, Figure 16 among the plurality of punch edges 161a, the second case 132a side punch edge 1611 connecting the second case 132a side outer wall 1381a facing the second case 132a to the bottom 1332 can be formed to be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the second case 132a side punch edge 1611a can be rounded, and formed with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

[0247] Further, the mold edge 162 side punch edge 1612 can also be formed while being rounded with a radius of curvature of 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the mold edge 162 side punch edge 1612 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less. Here, at the boundary points P2 and P4 of the punch edge 161a and the outer wall 138, it is preferable that the slope be continuous.

[0248] Hereinafter, in another embodiment of the present application, the description of the contents overlapping with one embodiment of the present application will be omitted. However, this is for the convenience of description, and is not intended to limit the scope of the right.

[0249] Figure 17 is a schematic view showing a state of folding the battery case 13a according to another embodiment of the present application, Figure 18 is a schematic view showing a state of folding the battery case 13a according to another embodiment of the present application.

[0250] The outer wall 138 has an upper end facing the opening of the cup portion 133, and the second case 132a, the side surface 134, and the degassing portion 137 extend to the outside of the cup portion 133. Here, the mold edge 162 connecting the upper end of the outer wall 138 and the second case 132a, the side surface 134, or the degassing portion 137 can be rounded with a radius of curvature corresponding to 1 / 20 to 1 / 6 of the depth D of the cup portion 133. Specifically, the mold edge 162 can be formed to be rounded with a radius of curvature of 1 mm or less, particularly 0.7 mm or less.

[0251] That is, according to another embodiment of the present application, as Figure 17 shown, there is no bridge portion in the battery case 13a, and the mold edge 1621 connects the cup portion 133 of the first case 131 to the second case 132a. To this end, the edge 213 of the mold 21 can be rounded, and the radius of curvature thereof is obtained by subtracting the thickness of the pouch film 135 from the mold edge 1621. For example, if the thickness of the pouch film 135 is 0.2 mm, the edge 213 of the mold 21 can be rounded with a radius of curvature of 0.8 mm or less, particularly 0.5 mm or less.

[0252] Further, the gap CL is reduced to 0.5 mm or less, and the outer wall 138a of the cup portion 133 can be formed to be similar to a vertical state. For example, as Figure 16 shown, the gap CL, which is the perpendicular distance between the mold edge perpendicular line V4 passing through the boundary point P1 of the mold edge 1621 and the second case 132a side outer wall 1381a and being perpendicular to the bottom 1332, and the edge perpendicular line V2 passing through the boundary point P2 of the second case 132a side punch edge 1611a and the second case 132a side outer wall 1381a and being perpendicular to the bottom 1332, can be 0.5 mm or less, particularly 0.35 mm or less.

[0253] Further, the electrode assembly 10 is accommodated such that one end of the electrode 101 is disposed between the edge perpendicular line V2 and a reference perpendicular line V3, which is vertically distant from the edge perpendicular line V2 by 0.75 mm, particularly 0.5 mm, and is perpendicular to the bottom 1332.

[0254] Therefore, according to another embodiment of the invention, since the moldability of the soft film 135 is improved, even if the cup portions 133 are formed slightly deeper, for example, with a depth D of 3 mm or more, particularly 7 mm or more, and even more particularly 10 mm or more, based on the case of forming two cup portions 133, cracks can be prevented from appearing in the punch edge 161a and the mold edge 162 of the cup portions 133. Furthermore, the outer wall 138 of the cup portions 133 can be formed in a near-vertical state, such that the angle of inclination with the bottom 1332 is 90° to 95°, particularly 90° to 93°, and while preventing damage to the electrode 101, the volume ratio of the electrode assembly 10 to the cup portion 133 can be further increased, thus increasing the energy efficiency relative to volume.

[0255] Figure 19 This is an enlarged view of the groove 1391a formed in the battery casing 13 according to another embodiment of the present invention.

[0256] According to another embodiment of the present invention, when the battery casing 13a is folded to manufacture the secondary battery 1a, the mold edge 1621 on the second casing 132a side becomes a folded portion 139a. Specifically, when the battery casing 13a is folded, the circular shape of the mold edge 1621 can also be unfolded, but the marks of the mold edge 1621 remain on the secondary battery 1, and these marks can become folded portions 139a. Therefore, the mold edge 1621 and the folded portion 139a on the second casing 132a side of the battery casing 13a correspond to each other.

[0257] For example, such as Figure 19 As shown, when the circular shape of the mold edge 1621 is not fully unfolded like a plane, the folded portion 139a includes an inwardly recessed groove 1391a for the secondary battery 1a. In this case, since the curvature of the folded portion 139a is less than the curvature of the mold edge 1621, the folded portion 139a can have a larger radius of curvature.

[0258] Because the mold edge 1621 has a curved surface and the outer wall 1381a of the mold edge 1621 has a planar shape, the deformation amounts are different. Therefore, when the battery casing 13 is folded, the outer wall 1381a of the mold edge 1621 deforms more, but the mold edge 1621 deforms less, only enough to unfold the circular shape to a certain extent. Then, when the battery casing 13 is folded, as... Figure 19 As shown, the increase or decrease in the amount of slope change changes around the boundary point P1. That is, each boundary point P1 becomes an inflection point. Therefore, the fold 139a can be formed as a surface between these two boundary points P1, i.e., the two inflection points.

[0259] Alternatively, even if the circular shape of the mold edge 1621 is fully unfolded, the boundary points P1 of the mold edge 1621 and the second case 132a side outer wall 1381 and the boundary points of the mold edge 1621 and the second case 132a form two lines (not shown) in the secondary battery 1a, respectively, and the folded portion 139a is formed as a plane between the two lines.

[0260] The width FW of the folded portion 139 is not more than the length of the mold edge 1621, and can be 1 mm to 3.2 mm, particularly 1 mm to 1.6 mm.

[0261] Figure 20 is a schematic top view showing a state before the degassing portion 337 of the battery case 33 is cut according to the related art.

[0262] The bridge portion 136 of the battery case 13 is folded to form the folded portion 139 on one side of the secondary battery 1, and the folded portion 139 integrally connects the first case 131 to the second case 132. However, the battery case 13 is formed by stretching the pouch film 135, in which case not only the cup portion 133 is limitedly elongated, but also the peripheral side surface 134 of the cup portion 133 is subtly elongated as a whole. Therefore, when the bridge portion 136 is folded, the subtly elongated portion of the side surface 134 accumulates, and thus is visible to the naked eye while protruding outward from both ends of the folded portion 139. This is called a bat ear 35 or 15.

[0263] The size of the bat ear 35 varies according to the thickness t' of the bridge portion 336, the gap CL', the radius of curvature R2' of the punch edge 361 of the cup portion 333, and the depth D' of the cup portion 333. That is, the thicker the thickness t' of the bridge portion 336, the larger the gap CL', the larger the radius of curvature R2' of the punch edge 361 of the cup portion 333, the larger the size of the bat ear 35 increases. However, in the related art, there are limitations in improving the thickness t' of the bridge portion 336, the radius of curvature R2' of the edge 361 of the cup portion 333, and the gap CL'. Therefore, as shown in Figure 20 , the size of the bat ear 35 is formed to be quite large, and reducing the size of the bat ear 35 is also limited.

[0264] When the size of the bat ear 35 is formed to be large, the unnecessary volume of the secondary battery 3 further increases, and thus the design value and the actual value of the shape and size of the secondary battery 3 are misaligned. Therefore, when the secondary battery 3 is assembled on the battery module 5 (see Figure 27 ), it is not easy to assemble, and considering the bat ear 35, there is a problem that the size of the secondary battery 3 must be designed to be small from the beginning. In addition, since the volume of the secondary battery 3 increases, there is also a problem that the energy density per volume decreases.

[0265] As described above, the pouch-type battery case 13 according to one embodiment of the present application can include a cup portion 133 in which an accommodation space 1331 that accommodates the electrode assembly 10 is provided, and a degassing portion 137 formed at one side of the cup portion 133 to discharge gas generated in the cup portion 133 through a degassing hole H.

[0266] Further, in the process of sealing the side surface 134, a molding process and a degassing process can be performed. Specifically, after the electrode assembly 10 is accommodated in the cup portion 133, in the battery case 13, an edge 1371 included in the degassing portion 137 is opened, and the remaining side surface 134 is sealed. When the edge of the battery case 13 is opened to form an opening, an electrolyte is injected into the battery case 13 through the opening.

[0267] After the electrolyte is injected into the battery case 13, the degassing portion 137 is first sealed, forming a temporary sealing portion 1340. Since the sealing portion 1341 is formed by subsequently sealing the degassing portion 137 by secondary sealing, it is preferable that the temporary sealing portion 1340 be formed at a position close to the edge 1371 in the degassing portion 137.

[0268] Thereafter, a molding process can be performed. The molding process (activation process) is a process of final charging to enable the secondary battery 1 to provide power. Since the molding process is performed after the temporary sealing portion 1340 is formed and the battery case 13 is completely sealed, the manufacturing of the secondary battery can be completed within a predetermined processing time by rapidly discharging gas at a high filling rate.

[0269] When the molding process is completed, gas is generated in the battery case 13. Therefore, the degassing hole H is punched in the degassing portion 137 of the battery case 13. Through the degassing hole H, gas is discharged from the inside of the battery case 13 to the outside. Here, while gas is easily discharged, the injected electrolyte can leak through the degassing hole H. To prevent this, it is preferable that the degassing hole H be punched at a position close to the temporary sealing portion 1340. When the degassing hole H is punched, a degassing process of discharging gas to the outside of the battery case 13 is performed.

[0270] When the degassing hole H is punched, the inside of the battery case 13 is again opened, and the electrolyte inside can leak to the outside. Therefore, a sealing portion 1341 is formed by sealing the boundary between the cup portion 133 and the degassing portion 137 by secondary sealing. Here, the sealing portion 1341 is formed between the cup portion 133 and the degassing hole H, and is preferably formed at a position close to the cup portion 133.

[0271] As described above, when the molding process and the degassing process are performed, the degassing hole H must be punched, and the primary sealing and the secondary sealing must be performed. In addition, when the secondary battery 1 is mass-produced, it is necessary to collectively manage the specifications and the quality of the secondary battery 1. For this purpose, the battery case 13 or the secondary battery 1 can be inspected using the inspection device 4 including the vision sensor 41 (see Figure 22 ).

[0272] According to the related art, the battery case 33 and the secondary battery 3 are manufactured as a whole in a pointed shape, which is limited. Therefore, when the battery case 33 is photographed using the vision sensor, the error in the size and the position of each component is large.

[0273] Specifically, when the manufacture of the secondary battery 1 is completed later, the battery module 5 can be manufactured by connecting the electrode lead 12 of a plurality of secondary batteries 1 to each other (see Figure 27 ). For this purpose, all positions of the electrode lead 12 formed in the plurality of secondary batteries 1 must be constant. However, in the related art, since the electrode 101 is spaced apart from the outer wall 338 of the cup portion 333 to some extent, the electrode assembly 10 can move inside the cup portion 333 before the sealing side surface 134. Therefore, when the secondary battery 3 is mass-produced, even if the volume of the cup portion 333 and the volume of the electrode assembly 10 are constant, the position of the electrode assembly 10 is slightly different, and thus the position of the electrode lead 12 is slightly different. Therefore, it is necessary to accurately measure the position of the electrode lead 12 using the inspection device 4.

[0274] In addition, in order to punch the degassing hole H at a correct position and size, and to perform the primary sealing and the secondary sealing at a correct position and size, it is necessary to accurately measure the position of the degassing portion 137. In addition, in order to effectively manage the overall quality of the plurality of secondary batteries 1, it is necessary to accurately measure the positions of the respective components of the battery case 13 or the secondary battery 1, such as the side surface 134, the folding portion 139, and the insulation portion 14 protruding from the battery case 13, and in addition, it is necessary to accurately measure the width between the cup portions 133.

[0275] In order to measure the position of the component, a specific reference line must be provided, and the vertical distance between the reference line and the component to be measured must be measured. For example, the electrode assembly 10 often moves inside the cup portion 333, and generally, moves in the left-right direction based on the long bar as shown in Figure 20 , that is, in the direction toward the folding portion 339 and the degassing portion 337. Therefore, in order to measure the position of the electrode lead 12, the position of the left edge or the right edge of the electrode lead 12 is measured, and in order to measure the vertical distance to the left edge or the right edge, a reference parallel to the left edge or the right edge is established.

[0276] However, in the related art, the outer wall 338 of the cup portion 333 is not formed similar to the vertical state, and the radius of curvature R2' of the punch edge 361 of the cup portion 333 is also large. Therefore, as shown in Figure 20 the punch edge 361 of the cup portion 333 does not clearly appear in the image when the battery case 33 is photographed using the vision sensor 41. Therefore, it is not possible to measure the position of the component based on the punch edge 361 of the cup portion 333, and the bat ear 35 close to the punch edge 361 is set as a reference, or the user manually sets the punch edge 361 of the cup portion 333 as a reference.

[0277] However, since the bat ear 35 is formed by folding the bridge portion 136 in a state where the peripheral side surface 134 of the cup portion 133 is also slightly elongated as a whole, the size of each bat ear 35 of the plurality of secondary batteries 1 is slightly different. Then, even when the position of the component is measured using the vision sensor, since the size of the bat ear 35 as a reference is different, the deviation of the position of the component between the secondary batteries 3 increases, making quality control difficult.

[0278] In particular, even when the position of the electrode lead 12 is measured by photographing the battery case 33 using the vision sensor, the position of the electrode lead 12 is slightly different, and thus, when the electrode lead 12 is connected to manufacture the battery module 5, there is a problem that the connection is not easy. In addition, in order to manufacture the battery module 5, when the plurality of secondary batteries 1 are sequentially stacked or aligned in a line, the position of the cup portion 333 is not correct, and thus, there is also a problem that the degree of arrangement of the plurality of secondary batteries 1 decreases.

[0279] In the case where the battery module 5 is manufactured by accommodating the secondary battery 3 in a separate housing 51 (see Figure 27 ), when the deviation of the measured value is large, the design tolerance when designing the housing 51 is set unnecessarily large, and thus, there is also a problem that the energy density compared to the volume of the battery module 5 also decreases.

[0280] Figure 21 is a schematic top view showing a state before the degassing portion 137 of the battery case 13 is cut according to one embodiment of the present application, Figure 22 is a block diagram of the inspection device 4 according to one embodiment of the present application.

[0281] According to one embodiment of the present application, as Figure 21As shown, since the moldability of the soft envelope 135 is improved, the thickness t of the bridge portion 136 is formed to be thinner, the curvature radius R2 of the edge 1611 of the cup portion 133 and the gap CL can be formed to be smaller, and the size of the bat ear 15 can be further reduced. Therefore, the secondary battery 1 can be easily assembled into the battery module 5, and the unnecessary volume of the secondary battery 1 is reduced, so that the energy density with respect to the volume can be increased.

[0282] Further, according to one embodiment of the present application, as Figure 21 As shown, since the punch edge 1611 of the cup portion 133 clearly appears in the image photographed by the battery case 13, the inspection device 4 can automatically set the punch edge 1611 of the cup portion 133 as the reference line ST, based on the punch edge 161 of the cup portion 133, the distance to each component of the battery case 13 or the secondary battery 1 can be accurately measured, and even the width CW between the cup portions 133 can be accurately measured. Therefore, the positions of the components of the battery case 13 or the secondary battery 1 can be accurately measured to reduce the error of the measurement value and reduce the deviation between the secondary batteries 1.

[0283] To this end, the inspection device 4 of the battery case 13 or the secondary battery 1 according to one embodiment of the present application includes a vision sensor 41 that photographs the battery case 13 to acquire an image of the battery case 13 or the secondary battery 1, a profile extraction portion 421 that extracts a profile of a component of the battery case 13 or the secondary battery 1 from the image, an image analysis portion 422 that analyzes the image to detect a profile corresponding to the punch edge 161 of the cup portion 133 in which the accommodation space 1331 in which the electrode assembly 10 is accommodated in the battery case 13 is provided, a reference line setting portion 423 that sets the profile corresponding to the punch edge 161 as a reference line ST, and a distance calculation portion 424 that calculates a distance from the reference line ST to the component.

[0284] Further, the inspection method of the battery case 13 or the secondary battery 1 according to one embodiment of the present application includes a process of photographing the battery case 13 to acquire an image of the battery case 13 or the secondary battery 1, a process of extracting a profile of a component of the battery case 13 or the secondary battery 1 from the image by a profile extraction portion 421, a process of analyzing the image to detect a profile corresponding to a punch edge 161 of a cup portion 133 in which an accommodation space 1331 in which an electrode assembly 10 is accommodated in a battery case 13 is provided, a process of setting the profile corresponding to the punch edge 161 as a reference line ST, and a process of calculating a distance from the reference line ST to the component.

[0285] Specifically, as Figure 22As shown, the inspection device 4 includes a vision sensor 41 and a controller 42. In addition, the above-described components can be connected to each other to communicate with each other through a bus (not shown). All components provided in the controller 42 can be connected to the bus through at least one interface or adapter, or can be directly connected to the bus. In addition, the bus can be connected to other subsystems in addition to the above-described components. The bus includes a memory bus, a memory controller, a peripheral bus, and a local bus.

[0286] The vision sensor 41 acquires an image by capturing a specific area to receive an image signal of the specific area. For this purpose, generally, 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 one embodiment of the present application, after the bridge portion 136 of the battery case 13 is folded, the battery case 13 is captured to acquire an image of each component of the battery case 13 or the secondary battery 1. Here, the components include the cup portion 133, the degassing portion 137, the electrode lead 12, the bat ears 15, the side surface 134, the folded portion 139, and the insulation portion 14 described above. Then, after the degassing portion 137 is cut, the manufacturing of the secondary battery 1 is completed. Therefore, if the vision sensor 41 captures the battery case 13 before the degassing portion 137 is cut, an image of the battery case 13 and the electrode lead 12 can be acquired, and if the battery case 13 is captured after the degassing portion 137 is cut, an image of the secondary battery 1 can be acquired.

[0287] The controller 42 receives an image signal acquired by the vision sensor 41 to identify the position of each component of the battery case 13 or the secondary battery 1 from the image signal. The controller 42 includes a contour extraction portion 421, an image analysis portion 422, a reference line setting portion 423, and a distance calculation portion 424. It is preferable to use a central processing unit (CPU), a micro control unit (MCU), or a digital signal processor (DSP) as the controller 42, but is not limited thereto. For example, various logic operation processors can be used.

[0288] The contour extraction portion 421 extracts a contour of each component of the battery case 13 or the secondary battery 1 from an image received from the vision sensor 41. Here, the contour extraction portion 421 can extract contours of all components appearing in the image, but is not limited thereto, and can set a region of interest (ROI) in a portion of the image, and can also extract only contours of components appearing within the ROI. To extract the contour, information about pixels of the image is first extracted, and for this purpose, a gradient formula generally used can be used. The contours of the battery case 13 and the electrode lead 12 are revealed through the extracted pixel information.

[0289] According to one embodiment of the present application, the radius of curvature R2 of the punch edge 161 of the cup portion 133 and the gap CL can be formed smaller, and since the outer wall 138 of the cup portion 133 is formed similar to a vertical state, the gradient of the pixel information in the image corresponding to the punch edge 161 of the cup portion 133 is large. Therefore, since the boundary between the contour and the background is clear, the contour corresponding to the punch edge 161 of the cup portion 133 can be clearly extracted.

[0290] The image analysis portion 422 analyzes the image and detects the contour corresponding to the punch edge 161 of the cup portion 133 in the battery case 13. To this end, the image analysis portion 422 matches the reference contour information of the punch edge 161 of the cup portion 133, which is stored in advance, with the extracted contour information to detect the contour corresponding to the punch edge 161 of the cup portion 133. In this case, the image analysis portion 422 can match the two pieces of information using a template matching technique.

[0291] The reference line setting portion 423 can set the contour corresponding to the punch edge 161 as the reference line ST. Since the cup portion 133 includes a plurality of punch edges 161, a plurality of contours corresponding to the punch edges 161 are also extracted. Here, in order to accurately measure the positions of the battery case 13 or each component of the secondary battery 1, the reference line setting portion 423 can preferably set the contour corresponding to the punch edge 161 closest to the component to be measured among the plurality of punch edges 161 as the reference line ST. Further, as described above, since the position of the component must be measured as a perpendicular distance from the reference line ST, the reference line setting portion 423 can set the contour corresponding to the punch edge 161 parallel to the edge of the component to be measured among the plurality of punch edges 161 as the reference line ST.

[0292] For example, in order to punch the degassing hole H and perform primary sealing and secondary sealing, the inspection device 4 can need to measure the position of the degassing portion 137. In this case, the reference line setting portion 423 can set the contour corresponding to the punch edge 1612, which is on the die edge 162 side and is close to the degassing portion 137 and parallel to the edge 1371 included in the degassing portion 137, among the plurality of punch edges 161, as the reference line ST.

[0293] For example, in order to check whether the positions of the electrode leads 12 are all constant, the inspection device 4 can have to measure the positions of the electrode leads 12. In this case, the reference line setting portion 423 can set the electrode lead 12 side contour corresponding to the punch edge 1611, which is on the folding portion 139 side and is close to the electrode leads 12 and parallel to the left and right edges of the electrode leads 12, among the plurality of punch edges 161, as the reference line ST.

[0294] Further, in order to measure the width between the cup portions 133, the reference line setting portion 423 can set one of the profiles of the two punch edge 161 corresponding to the width boundary of the cup portion 133 among the plurality of punch edges 161 as the reference line ST.

[0295] That is, as long as the reference line setting portion 423 accurately measures the positions of the respective components of the battery case 13 or the secondary battery 1, the reference line setting portion 423 can set various profiles as the reference line ST without limitation.

[0296] The distance calculating portion 424 calculates the 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 profile corresponding to the die edge 162 side punch edge 1612 is set as the reference line ST, the distance calculating portion 424 can calculate the distance from the reference line ST to the edge included in the degassing portion 137. Or, if the profile corresponding to the fold portion 139 side punch edge 1611 is set as the reference line ST, the distance calculating portion 424 can calculate the distance from the reference line ST to one edge of the electrode lead 12, and can also calculate the distance to the profile corresponding to the die edge 162 side punch edge 1612.

[0297] The distance calculating portion 424 can use information about the relationship between the number of pixels in the image and the actual distance that is stored in advance. That is, in the image, the distance calculating portion 424 can calculate the distance from the reference line ST to each component as the number of pixels, and then calculate the actual distance corresponding to the calculated number of pixels by using information about the relationship between the number of pixels in the image and the actual distance that is stored in advance.

[0298] The inspection device 4 can further include a storage 44. The storage 44 stores programs for processing and controlling operations of the inspection device 4 and various data generated during execution of each program or received signals. Specifically, reference information about the battery case 13 can be stored to enable the image analysis section 422 to detect a profile corresponding to the punch edge 1611 of the cup portion 133. Here, the reference information about the battery case 13 includes reference profile information about the punch edge 1611 of the cup portion 133 and reference information about distances to components of the battery case 13 or the secondary battery 1. This can be stored in the storage 44 directly by a user, or the inspection device 4 can generate and store the reference information through repeated learning. Further, the storage 44 can store information about a relationship between a number of pixels in an image and an actual distance to enable the distance calculation section 424 to calculate an actual distance from the reference line ST to each component. Further, inspection result information of the battery case 13 to be inspected can also be stored. This storage 44 can be embedded in the inspection device 4, but can be provided as a separate storage server. The storage 44 includes a non-volatile memory device and a volatile memory device. The non-volatile memory device can be a NAND flash memory that is small in volume, light in weight, and resistant to external impact, and the volatile memory device can be a DDR SDRAM.

[0299] The controller 42 can further include a defect determination section 425 for determining whether the battery case 13 to be inspected is defective. The defect determination section 425 can compare the reference information about the battery case 13 stored in the storage 44 with the inspection result information of the battery case 13 to be inspected. Further, if the inspection result information is included within an error range of the reference information, it is determined that the battery case 13 is normal. However, if the inspection result information is outside the error range of the reference information, it is determined that the battery case 13 is defective.

[0300] The inspection device 4 can further include a display 43 for receiving and displaying an image signal. The display 43 receives a signal of an image and displays the image to a user. Further, when the profile extraction section 421 extracts a profile of the battery case 13, the profile can be displayed on the image to enable the user to check the profile through the display 43. The display 43 can 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). Further, the display 43 is connected to a bus through a video interface, and data transmission between the display 43 and the bus can be controlled by a graphic controller.

[0301] The inspection device 4 can further include an alarm 45 that generates an alarm when the defect determination section 425 determines that the battery case 13 is defective. When an alarm is generated, it is preferable to generate a sound or a visual alarm such as a light or a warning sound to enable the user to intuitively know.

[0302] The respective components of the visual sensor 41, the controller 42, the storage section 44, and the display section 43 described thus far can be implemented using software such as tasks, classifications, subroutines, processes, objects, execution threads, and programs that are executed in predetermined areas of a memory, or hardware such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and can also be implemented by a combination of software and hardware. The components can be included in a computer-readable storage medium, or portions of the components can be scattered and distributed in multiple computers.

[0303] Furthermore, each block can represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the function(s) noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved.

[0304] When the inspection device 4 according to one embodiment of the present application is used, since the punch edge 1611 of the cup portion 133 is clearly displayed, the inspection device 4 can automatically set the punch edge 161 of the cup portion 133 as a reference line ST and accurately measure the distance to each component of the battery case 13 based on the punch edge 1611 of the cup portion 133. For example, the size and position of the degassing portion 137 can be measured, and the size and position of the cup portion 133, the electrode lead 12, the bat ear 15, and the side surface 134, the folding portion 139, and the insulating portion 14 can be accurately identified even after the manufacturing of the secondary battery 1 is completed. Thus, it can be easily determined whether the secondary battery 1 is defective, and even if the secondary battery 1 is mass-produced, its specifications and quality can be effectively collectively managed.

[0305] In particular, since the position of the electrode lead 12 is accurately measured, when the electrode lead 12 is connected to manufacture the battery module 5, the components can be easily connected to each other. Furthermore, the position of the cup portion 333 is accurately measured, and thus, when a plurality of secondary batteries 1 are sequentially stacked or aligned in a line to manufacture the battery module 5, the alignment of the plurality of secondary batteries 1 can be improved.

[0306] Figure 23 is a schematic view showing a state in which the degassing portion of the battery case 13 according to one embodiment of the present application is cut to completely manufacture the secondary battery 1.

[0307] After the battery case 13 is twice sealed to form the sealing portion 1341, the degassing portion 137 is cut by providing a cutting line CT outside the sealing portion 1341. As a result, as shown in Figure 23 the degassing portion 137 can be shortened, and the volume of the secondary battery 1 can be reduced. Through the above-described process, the manufacturing of the pouch-type secondary battery 1 is completed.

[0308] In the side surface 134 remaining after the cutting of the degassing portion 137, the electrode lead 12 does not protrude in the plurality of side surfaces 134. However, if the side surface 134 remains as is after the sealing, the total volume of the secondary battery 1 increases. Therefore, in order to increase the energy density with respect to the volume, it is desirable to fold the side surface 134.

[0309] As shown in FIG. 7, the side surface 134 can include a sealed portion 1341 and an unsealed portion 1342. The sealed portion 1341 is a sealed region arranged on the opposite outer side, and the unsealed portion 1342 is an unsealed region arranged on the opposite inner side. Figure 23

[0310] Specifically, when the sealed portion 1341 is formed by the secondary sealing of the battery case 13, the sealed portion 1341 is not directly connected to the cup portion 133 but can be formed to be spaced to some extent. When the side surface 134 is sealed, heat and pressure are applied to the side surface 134 using a separate sealing tool (not shown). However, if the side surface 134 is sealed while the sealing tool is in close contact with the cup portion 133, the sealant layer 1351 arranged inside the side surface 134 partially melts and leaks to the electrode assembly 10, thereby contaminating the electrode assembly 10. In addition, the heat of the sealing tool is transferred to the electrode assembly 10, thereby damaging the electrode assembly 10. Therefore, it is preferable to seal the side surface 134 in a state in which the sealing tool is spaced to some extent from the cup portion 133. Then, the portion sealed by the sealing tool becomes the sealed portion 1341, and the portion not sealed due to the spacing of the sealing tool from the cup portion 133 becomes the unsealed portion 1342.

[0311] Figure 24 FIG. 7 is a schematic side view showing a state in which the side surface 334 is folded according to the related art, Figure 25 FIG. 8 is a schematic top view showing a state in which the side surface 334 is folded according to the related art.

[0312] In the related art, when the side surface 334 is folded, there is a problem in that the side surface 334 is not fixed and is unfolded again at a predetermined angle. Specifically, as described above, the pouch film 135 is formed by layering the sealant layer 1351, the moisture barrier layer 1352, the stretch assisting layer 1354, and the surface protection layer 1353. Among them, since the sealant layer 1351 contains a first polymer, particularly polypropylene (PP), the flexibility and elasticity are good. Therefore, when the side surface 334 is folded, the restoring force to return to the initial 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 surface 334 is folded, the limit of elastic deformation is exceeded, and thus the holding force to maintain the folded state is large.

[0313] ​However, in the soft pouch according to the related art, the thickness of the moisture barrier layer is about 30 to 50 μm, and the thickness of the sealant layer is about 60 to 100 μm. That is, the thickness of the moisture barrier layer is formed to be significantly thinner than the thickness of the sealant layer. Therefore, the restoring force is greater than the holding force, and thus the side surface 334 is not fixed and is unfolded again at a predetermined angle. Then, there is a problem in that the unnecessary volume of the secondary battery 3 is increased due to the side surface 334.

[0314] To solve this problem, as shown in Figure 24 and Figure 25 , the adhesive tape 38 is separately attached to the side surface 334. In particular, the adhesive tape 38 is attached together to the outer surface of the side surface 334 and the bottom 3332 of the cup portion 333 to fix the side surface 334 to the cup portion 333, thereby preventing the side surface from being unfolded again. However, in this case, as shown in Figure 24 , there is a problem in that the total thickness of the secondary battery 3 is increased due to the thickness of the adhesive tape 38 itself. In addition, after the process of folding the side surface 334, an additional process of attaching the adhesive tape 38 is required, and the process requires a large amount of time, thereby increasing the number of processes and reducing the manufacturing yield of the secondary battery 3.

[0315] When the degassing process is performed, the internal pressure of the cup portion 133 is decreased as gas is discharged from the inside of the battery case 13 to the outside. In the related art, the electrode assembly 10 is disposed to be spaced apart from the outer wall 338 of the cup portion 333 by a certain degree. Therefore, 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 decreasing the internal pressure of the cup portion 333, the outer wall 338 or the bottom 3332 of the cup portion 333 can be deformed. In particular, as shown in Figure 24 , when the folded portion side outer wall 338 of the secondary battery 3 is inwardly recessed, an edge high phenomenon in which the folded portion 339 side punch edge 361 of the cup portion 333 is outwardly protruded to increase the height occurs. Due to the edge high phenomenon, the unnecessary thickness of the secondary battery 3 is increased, and thus there is a problem in that the energy density with respect to the volume is reduced. In addition, since the folded portion 339 side outer wall 338 of the cup portion 333 is deformed, the appearance of the secondary battery 3 is not beautiful, and thus there is a problem in that the marketability is also decreased. In addition, there is a problem in that the size of the bat ear 15 is further increased, and the shape is protruded due to the edge high phenomenon.

[0316] Figure 26 is a schematic side view showing a state in which the side surface 134 is folded according to one embodiment of the present application.

[0317] According to one embodiment of the invention, in the flexible film 135, 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, making the moisture barrier layer 1352 thicker than in the prior art. Therefore, due to the further increase in holding force when the side 134 is folded, the side 134 can be prevented from unfolding again without the need to attach a separate adhesive tape 38.

[0318] Therefore, a secondary battery 1 according to one embodiment of the present invention includes: an electrode assembly 10 formed by stacking electrodes 101 and a separator 102; and a pouch-type battery housing 13 having a cup portion 133 internally accommodating the electrode assembly 10. The pouch-type battery housing 13 includes a side surface 134 extending outward from the cup portion 133, the side surface 134 including a sealed portion 1344 disposed on the opposite outer side and sealed, and an unsealed portion 1345 disposed on the opposite inner side and unsealed. Therefore, the side surface 134 is not bonded to the cup portion 133, and the unsealed portion 1345 is folded.

[0319] That is, such as Figure 26 As shown, in the secondary battery 1, after the side 134 is folded towards the cup portion 133, the side 134 does not adhere to the cup portion 133 while remaining folded, and therefore does not unfold. In this case, the side 134 can be folded at an angle of 85° to 95°, especially 88° to 92°. Furthermore, the side 134 can be folded near the cup portion 133 so that the side 134 contacts the outer wall 138 of the cup portion 133. In particular, as described above, the side 134 may include a sealing portion 1341 arranged on the relatively outer side and thus sealed, and a non-sealing portion 1342 arranged on the relatively inner side and thus not sealed. Furthermore, when the side 134 is folded, it is preferable to fold the non-sealing portion 1342 that is relatively close to the cup portion 133. Therefore, 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 do not adhere to each other, and the holding force of the side 134 increases to maintain the folded state.

[0320] When two cup portions 133 are formed on the soft membrane 135, the depth D of the cup portions 133 can be shallower than when only one cup portion 133 is formed. This is because, as described above, not only are the cup portions 133 elongated in a concentrated manner, but the peripheral side surfaces 134 of the cup portions 133 are also slightly elongated as a whole. However, if the width of the side surfaces 134 is longer than the depth D of the cup portions 133, then when the side surfaces 134 are folded only once, the outer ends 1343 of the side surfaces 134 will protrude more outward than the bottom 1332 of the cup portions 133.

[0321] Therefore, if two cup portions 133 are formed on the soft membrane 135, then as shown in the figure, it is possible to use... Figure 26A double-sided folding (DSF) method of folding the side surface 134 twice is illustrated. Specifically, the side surface 134 can include a first folding portion 1344 and a second folding portion 1345. The first folding portion 1344 is a portion folded at a position relatively close to the outer end 1343, and the second folding portion 1345 is a portion folded at a position relatively close to the cup portion 133. Thus, after the side surface 134 is folded based on the first folding portion 1344, the side surface 134 can be folded based on the second folding portion 1345. In this case, the first folding portion 1344 can be provided on the sealed portion 1341 of the side surface 134, and the second folding portion 1345 can be provided on the unsealed portion 1342 of the side surface 134. Also, the side surface 134 can be folded at an angle of 170° to 180°, particularly at an angle of 180°, in the first folding portion 1344. Also, the second folding portion 1345 can be folded at an angle of 85° to 95°, particularly at an angle of 88° to 92°. Thus, it is possible to prevent the outer end 1343 of the side surface 134 from protruding more outward than the bottom 1332 of the cup portion 133.

[0322] According to one embodiment of the present application, since the electrode assembly 10 can be disposed very close to the outer wall 138 of the cup portion 133, unnecessary volume of the cup portion 133 is reduced. Thus, even if the internal pressure of the cup portion 133 is lowered by performing a degassing process, the outer wall 138 or the bottom 1332 of the cup portion 133 can be prevented from being deformed. That is, as illustrated, it is possible to prevent the occurrence of a phenomenon in which the edge is high, and thus, the energy density with respect to the volume is not reduced. Figure 26

[0323] Figure 27 FIG. 1 is a schematic view of a battery module 5 according to one embodiment of the present application.

[0324] Since large electronic devices in automobiles or the like require large output power, many secondary batteries 1 are required. In order to facilitate the movement and installation of the secondary batteries 1, the battery module 5 can be manufactured. When a plurality of secondary batteries 1 are installed in the battery module 5, it is possible to stably supply power to the outside.

[0325] In order to generate electricity in the electrode assembly 10 of the secondary battery 1, a chemical reaction occurs between the electrode 101 and the electrolyte, and heat is generated in the process. However, when the ambient temperature excessively increases due to the heat, there is a problem in that a failure occurs in the circuit of an electrical device in which the secondary battery 1 is installed, or the lifespan of the electrical device is shortened. Thus, the battery module 5 includes a cooling system for cooling the secondary battery 1. The cooling system is mainly divided into a water cooling type using cooling water to cool the secondary battery and an air cooling type using air to cool the secondary battery. Among them, the cooling efficiency of the water cooling type cooling system is higher than that of the air cooling type cooling system, and thus, the water cooling type cooling system is more widely used.

[0326] ​The cooling system includes a cooling plate directly cooling the secondary battery 1, and a separate flow channel formed inside the cooling plate to flow cooling water. In addition, as the passage thickness and length increase, the surface area increases to improve cooling efficiency.

[0327] To manufacture the battery module 5, first, a plurality of secondary batteries 1 are manufactured, and then the secondary batteries 1 are connected to each other and accommodated in the case 51. In this case, the secondary batteries 1 can be aligned in a line and stacked. As shown in FIG. 1, when the secondary batteries 1 are accommodated in the case 51, the long side surfaces of the secondary batteries 1 can face downward, and cooling plates (not shown) can be formed on the bottom surface of the case 51. Accordingly, the long side surfaces of the secondary batteries 1 can be cooled by the cooling plates to improve cooling efficiency. Figure 27

[0328] The folded portion 139 formed by folding the bridge portion 136 is formed on one side of the secondary battery 1, and the area remaining after the cutting of the degassing portion 137, i.e., the side surface 134, is formed on the other side. However, if the cooling plate cools from the side of the side surface 134 among the plurality of surfaces of the secondary battery 1, the distance between the cooling plate and the electrode assembly 10 increases due to the side surface 134, thereby reducing cooling efficiency. Accordingly, it is preferable that the cooling plate cool from the side of the folded portion 139 among the long side surfaces of the secondary battery 1. To this end, when the secondary battery 1 is accommodated in the case 51, the folded portion 139 can be accommodated in a direction toward the cooling plate, i.e., downward.

[0329] Figure 28 is an enlarged front view showing a state in which the secondary battery 3 is accommodated in the case 51 of the battery module 5 according to the related art, Figure 29 is an enlarged side view showing a state in which the secondary battery 3 is accommodated in the case 51 of the battery module 5 according to the related art.

[0330] As described above, in the related art, the size of the bat ear 35 is limited to be reduced. In particular, it is limited to reduce the size of the bat ear 35 to a certain value (e.g., 1.5 mm) or less while forming the depth D' of the cup portion 333 to be deep enough (e.g., 6.5 mm or more).

[0331] In addition, in the related art, the angle θ' formed between the folded portion 339 and the inner edge 35a of the bat ear 35 is formed to be less than 151 degrees.

[0332] ​Here, the angle θ' can refer to an angle formed by a virtual first line Ll corresponding to the folding portion 339 and a virtual second line L2 corresponding to the inner edge 35a of the bat ear 35. In particular, the first line Ll and the second line L2 can be determined through image analysis. For example, the first line Ll and the second line L2 can be extracted by connecting a plurality of edge points identified within a region of interest (ROI) in the vision device. Thus, even when the folding portion 339 or the inner edge 35a of the bat ear 35 is partially bent or curved, the first line Ll and the second line L2 can be clearly defined. Since image analysis is a well-known technology, a detailed description thereof will be omitted.

[0333] Thus, as Figure 28 indicated, when the secondary battery 3 is accommodated in the case 51, the case 51 and the folding portion 339 are spaced apart from each other by a large gap d' (e.g., greater than 1.5 mm) due to the bat ear 35. Thus, the gap d' can hinder cooling of the cooling plate, and thus the cooling efficiency can be reduced. To solve this problem, the heat transfer material 52 is injected into a space between the cooling plate and the folding portion 339 of the secondary battery 1, and thus the cooling plate cools the folding portion 139 through the heat transfer material 52. For example, the heat transfer material 52 can be thermal grease.

[0334] However, if the size of the bat ear 15 is large, since a large amount of heat transfer material 52 must be injected, the cost increases, and since the gap d' between the cooling plate and the folding portion 139 is large, the cooling efficiency is still low.

[0335] Further, when a degassing process is performed through the degassing hole H, as Figure 29 indicated, when the internal pressure of the battery case 33 is reduced, the folding portion 339 of the battery case 33 is in close contact with the electrode assembly 10. However, in the related art, reduction of the gap CL' is limited, and the width of the folding portion 339 is also formed to be large. Thus, the space 37 between the outer wall 338 of the cup portion 333 and the electrode assembly 10 is also formed to be large, and there is a problem in that the energy density with respect to the volume of the secondary battery 3 is reduced. Further, since the distance at which the electrode assembly 10 is separated from the thermal grease 52 is also increased, there is a problem in that the cooling efficiency is further reduced.

[0336] Figure 30 FIG. 1 is a perspective view showing a battery module according to one embodiment of the present application, Figure 31 FIG. 2 is a side view showing a state in which a secondary battery is accommodated in a case of the battery module according to one embodiment of the present application.

[0337] The pouch-type secondary battery 1 according to one embodiment of the present application includes: an electrode assembly 10 in which electrodes 101 and separators 102 are stacked; and a pouch-type battery case 13 having a cup portion 133 in which the electrode assembly 10 is accommodated, wherein the battery case 13 includes: a first case 131 and a second case 132, in which the cup portion 133 is formed in at least one of the first case and the second case; a folding portion 139 for integrally connecting the first case 131 to the second case 132; and bat ears 15 protruding outward from a portion of both ends of the folding portion 139, wherein a length d of the bat ears 15 is 1.5 mm or less.

[0338] Further, an angle Θ between the folding portion 139 and an inner edge 15a of the bat ears 15 can be formed to be greater than 151 degrees. Further, the angle Θ can be 180 degrees or less. Further, when the angle Θ is 180 degrees, it can mean a state in which the bat ears 15 are not present.

[0339] Here, the angle Θ' can be an angle formed by a first virtual line L1 corresponding to the folding portion 139 and a second virtual line L2 corresponding to the inner edge 15a of the bat ears 15. The description of the first line L1 and the second line L2 will be obtained from the above description. The battery module 5 according to one embodiment of the present application includes: a pouch-type secondary battery in which an electrode assembly 10 in which electrodes 101 and separators 102 are stacked is accommodated in a cup portion 133 formed in a pouch-type battery case 13; and an outer case 51 in which the secondary battery 1 is accommodated inside, wherein the battery case 13 includes: a first case 131 and a second case 132, in which the cup portion 133 is formed in at least one of the first case and the second case; a folding portion 139 for integrally connecting the first case 131 to the second case 132; and bat ears 15 protruding outward from a portion of both ends of the folding portion 139, wherein a length d of the bat ears 15 is 1.5 mm or less.

[0340] As described above, the bat ears 15 are formed to protrude outward from a portion of both ends of the folding portion 139 by folding the bridge portion 136. According to one embodiment of the present application, the length of such bat ears 15 can be 1.5 mm or less, and particularly 1 mm or less. The length of the bat ears 15 can be a length measured from the outermost protruding portion of the folding portion 139 side outer wall 1381 to the outermost end of the bat ears 15. In this case, as described above, the folding portion 139 side outer wall 1381 can have an inclination angle of 90 to 95° with the bottom portion 1332 due to the gap CL. In consideration of this, as an example of measuring the bat ears, the length of the bat ears 15 can be a length measured from the outermost protruding portion of the folding portion 139 side outer wall 1381 to the outermost end of the bat ears 15.

[0341] The length of the bat ear 15 can be measured directly contacting the secondary battery 1 using a ruler or a vernier caliper, or can be measured in a non-contact manner using a laser displacement sensor or a vision sensor.

[0342] As described above, the method of measuring the length of the bat ear is described as an example, and the case where the method is limited only to the above-described measuring method is not included within the scope of the present application. The length of the bat ear can be the length of the bat ear within the meaning of the present application as long as it falls within the scope of the claims and the spirit of the present application.

[0343] According to one embodiment of the present application, since the moldability of the soft envelope 135 is improved, the thickness t of the bridge portion 136 is formed to be thinner, and the curvature radius R2 of the edge 1611 of the cup portion 133 and the gap CL can be formed to be smaller.

[0344] Therefore, while the depth D of the cup portion 133 is formed to be 3 mm or more, particularly 6.5 mm or more, the length D of the bat ear 15 can also be further reduced to 1.5 mm or less, particularly 1 mm or less. Therefore, as shown in FIG. 6, the interval d between the case 51 and the folded portion 139 can be reduced to 1.5 mm or less. As a result, the thickness of the heat transfer material 52 inside the case 51 can be 1.5 mm or less, and therefore the injection amount of the thermal grease 52 can be further reduced to lower the cost and improve the cooling efficiency. Figure 30

[0345] In addition, as shown in FIG. 7, the gap CL can be made smaller, and the width FW of the folded portion 139 can be made smaller. Therefore, the space 17 between the outer wall 138 of the cup portion 133 and the electrode assembly 10 is reduced, and therefore the energy density with respect to the volume of the secondary battery 1 can be increased. In addition, since the distance between the electrode assembly 10 and the thermal grease 52 is also reduced, the cooling efficiency can be further improved. Figure 31

[0346] Those skilled in the art to which the present application pertains will appreciate that the present application can be embodied in other specific forms without changing the technical idea or essential characteristics thereof. Therefore, the above-described disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present application is defined by the appended claims rather than the foregoing description and exemplary embodiments described therein. Various modifications made within the meaning of the claims equivalent to the present application and within the claims are to be construed as being within the scope of the present application.

[0347] [Legend of Reference Numerals]

[0348] 1: Secondary battery 2: Molding apparatus

[0349] 3: Secondary battery according to the related art 4: Inspection device

[0350] ​​5: electrode module 10: electrode assembly

[0351] 11: electrode tab 12: electrode lead

[0352] 13: battery case 14: insulating portion

[0353] 15: bat ear 16: rim

[0354] 17: space 21: mold

[0355] 22: punch 33: battery case according to the related art

[0356] 35: bat ear according to the related art 36: rim according to the related art

[0357] 37: space according to the related art 38: adhesive tape according to the related art

[0358] 41: vision sensor 42: controller

[0359] 43: display portion 44: storage portion

[0360] 45: alarm portion 51: housing

[0361] 52: heat lubricant 101: electrode

[0362] 102: separator 111: positive electrode tab

[0363] 112: negative electrode tab 121: positive electrode lead

[0364] 122: negative electrode lead 131: first case

[0365] 132: second case 133: cup portion

[0366] 134: side surface 135: soft envelope

[0367] 136: bridge portion 137: degassing portion

[0368] 138: outer wall 139: folded portion

[0369] 161: punch edge 162: mold edge

[0370] 163: thickness edge 164: corner portion

[0371] 211: formed portion 212: partition wall

[0372] 213: edge of mold 221: edge of punch

[0373] 333: cup portion according to the related art 334: side surface according to the related art

[0374] 336: bridge portion according to prior art 337: degassing portion according to prior art

[0375] 338: outer wall according to prior art 339: folded portion according to prior art

[0376] 361: punch edge according to prior art 362: die edge according to prior art

[0377] 421: contour extraction portion 422: image analysis portion

[0378] 423: reference line setting portion 424: distance calculation portion

[0379] 425: defect determination portion 1021: peripheral portion

[0380] 1331: accommodation space 1332: bottom portion

[0381] 1333: outer wall 1340: temporary sealing portion

[0382] 1341: sealing portion 1342: non-sealing portion

[0383] 1343: outer end 1344: first folded portion

[0384] 1345: second folded portion 1351: sealant layer

[0385] 1352: moisture barrier layer 1353: surface protection layer

[0386] 1354: stretch assisting layer 1371: edge

[0387] 1381: bridge portion side outer wall 1382: degassing portion side outer wall

[0388] 1391: groove 1611: bridge portion side punch edge

[0389] 1612: degassing portion side punch edge 1613: first punch edge

[0390] 1614: second punch edge

Claims

1. A pouch-type secondary battery comprising: an electrode assembly in which an electrode and a separator are stacked; a pouch-type battery case including a cup portion configured to accommodate the electrode assembly inside, wherein the battery case includes: a first case and a second case, at least one of which includes a cup portion; a folding portion configured to integrally connect the first case to the second case; and bat ears protruding outward from a portion of each of both ends of the folding portion, wherein a length of the bat ears is 1.5 mm or less, wherein the battery case is manufactured by molding a pouch film, wherein the pouch film includes: a sealant layer made of a first polymer and formed at an innermost layer; a surface protection layer made of a second polymer and formed at an outermost layer; and a moisture barrier layer laminated between the surface protection layer and the sealant layer, wherein the moisture barrier layer is formed as an aluminum alloy thin film having a thickness of 50 to 80 μm and a particle size of 10 to 13 μm, and wherein a thickness of the sealant layer is 60 to 100 μm.

2. The pouch-type secondary battery according to claim 1, wherein A length of an outermost end of the bat ears from a folding portion side outer wall is 1.5 mm or less.

3. The pouch-type secondary battery according to claim 1, wherein An angle between the folding portion and an inner edge of the bat ears is greater than 151 degrees.

4. The pouch-type secondary battery according to claim 1, wherein The folding portion includes a groove that is recessed inward.

5. The pouch-type secondary battery according to claim 1, wherein The battery case includes a pair of protrusions that protrude outward and have a groove therebetween, and A distance between an innermost portion of the groove and an outermost portion of the protrusions is 0.8 mm or less.

6. The pouch-type secondary battery according to claim 1, wherein The cup portion includes a plurality of punch edges that connect a plurality of outer walls configured to surround a circumference of the punch edges to a bottom portion, respectively, and At least one of the punch edges is rounded.

7. The pouch-type secondary battery according to claim 6, wherein The punch edges have a radius of curvature corresponding to 1 / 20 to 1 / 6 of a depth of the cup portion.

8. The pouch-type secondary battery according to claim 6, wherein The cup portion further includes a thickness edge configured to connect two of the outer walls adjacent to each other, and wherein the thickness edge connects to two of the punch edges adjacent to each other to form a corner portion.

9. The pouch-type secondary battery according to claim 8, wherein At least one of the corner portions is rounded, and A radius of curvature of the corner portion is equal to or greater than a radius of curvature of at least one of the punch edges or the thickness edge. 10.The pouch-type secondary battery of claim 1, wherein, The first case and the second case each include the cup portion, and The pouch-type battery case includes a bridge portion formed between the two cup portions, wherein the bridge portion is rounded. 11.The pouch-type secondary battery of claim 1, wherein A depth of the cup portion is 6.5 mm or more. 12.The pouch-type secondary battery of claim 1, wherein, The area of the electrode assembly is 15000 mm 2 up to 100000 mm 2 . 13.The pouch-type secondary battery of claim 1, wherein, The aluminum alloy thin film includes an AA8021 aluminum alloy. 14.The pouch-type secondary battery of claim 1, wherein, The aluminum alloy thin film includes 1.3 to 1.7 wt% of iron and 0.2 wt% or less of silicon. 15.The pouch-type secondary battery of claim 1, wherein, A thickness of the moisture barrier layer is 55 to 65 μm, and A thickness of the sealant layer is 75 to 85 μm. 16.The pouch-type secondary battery of claim 1, further comprising a stretch assisting layer made of a third polymer and laminated between the surface protection layer and the moisture barrier layer.

17. The pouch-type secondary battery according to claim 16, wherein A thickness of the stretch assisting layer is 20 to 50 μm.

18. A pouch-type secondary battery, comprising: An electrode assembly in which electrodes and separators are stacked; The pouch-type battery casing includes a cup portion configured to internally house the electrode assembly. The battery casing includes: A first housing and a second housing, at least one of the first housing and the second housing including a cup portion; The folding portion is configured to integrally connect the first housing to the second housing; and Bat ears, protruding outward from a portion at each end of the fold. Wherein, the angle between the folded portion and the inner edge of the bat ear is greater than 151 degrees. The battery casing is manufactured by molding a flexible film. The soft film includes: A sealant layer, made of a first polymer and formed in the innermost layer; A surface protective layer, made of a second polymer and formed on the outermost layer; and A moisture-blocking layer is layered between the surface protective layer and the sealant layer. The moisture-blocking layer is formed as an aluminum alloy film with a thickness of 50 μm to 80 μm and a particle size of 10 μm to 13 μm. The thickness of the sealant layer is 60 μm to 100 μm.

19. A battery module, comprising: An electrode assembly in which electrodes and separators are stacked; A pouch-type secondary battery is housed in a cup-shaped portion formed within a pouch-type battery casing; as well as The outer casing, which houses the secondary battery, The battery casing includes: A first housing and a second housing, at least one of the first housing and the second housing including a cup portion; The folding portion is configured to integrally connect the first housing to the second housing; and Bat ears, protruding outward from a portion at each end of the fold. The bat ears are less than 1.5 mm in length. The battery casing is manufactured by molding a flexible film. The soft film includes: A sealant layer, made of a first polymer and formed in the innermost layer; A surface protective layer, made of a second polymer and formed on the outermost layer; and A moisture-blocking layer is layered between the surface protective layer and the sealant layer. The moisture-blocking layer is formed as an aluminum alloy film with a thickness of 50 μm to 80 μm and a particle size of 10 μm to 13 μm. The thickness of the sealant layer is 60 μm to 100 μm.

20. The battery module of claim 19, wherein, The angle between the fold and the inner edge of the bat ear is greater than 151 degrees.

21. The battery module of claim 19, wherein, The housing includes a cooling plate configured to cool the secondary battery.

22. The battery module of claim 21 further includes a heat transfer material formed between the cooling plate and the folded portion of the secondary battery.

23. The battery module of claim 22, wherein, The thickness of the heat transfer material inside the outer casing is less than 1 mm.

24. A battery module, comprising: An electrode assembly in which electrodes and separators are stacked; A pouch-type secondary battery is housed in a cup-shaped portion formed within a pouch-type battery casing; as well as The outer casing, which houses the secondary battery, The battery casing includes: a first housing and a second housing, at least one of the first housing and the second housing including a cup portion; a folding portion configured to integrally connect the first housing to the second housing; and bat ears protruding outward from a portion of each of both ends of the folding portion, wherein an angle between the folding portion and inner edges of the bat ears is greater than 151 degrees, wherein the battery case is manufactured by molding a pouch film, wherein the pouch film includes: a sealant layer made of a first polymer and formed at an innermost layer; a surface protection layer made of a second polymer and formed at an outermost layer; and a moisture barrier layer laminated between the surface protection layer and the sealant layer, wherein the moisture barrier layer is formed as an aluminum alloy thin film having a thickness of 50 μm to 80 μm and a particle size of 10 μm to 13 μm, and wherein the sealant layer has a thickness of 60 μm to 100 μm.

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