Pouch-type battery case, rechargeable battery, and battery molding apparatus

Abstract

In a pouch-type battery case 10 configured to accommodate an electrode assembly 21 having a structure in which electrodes 23 and 25 and a separator 24 are alternately arranged, the battery case 10 includes a pouch film 1 having a film thickness d1, a first surface 31, and a second surface 34; a first cup portion 13 formed in the pouch film 1 having a concave shape extending from the first surface 31 toward the second surface 34; a second cup portion 15 formed in the pouch film 1 having a concave shape extending from the first surface 31 toward the second surface 34; and a bridge portion 14 formed in the pouch film 1 between the first cup portion 13 and the second cup portion 15 and connecting the first cup portion 13 to the second cup portion 15. The bridge portion 14 includes a notch 41 formed in the first surface 31 protruding toward the second surface 34.

Description

[Technical Field]

[0001] The present disclosure relates to a pouch-type battery case, a secondary battery, and a battery molding apparatus. [Background Art]

[0002] In modern society, with the popularization of portable devices such as mobile phones, notebook computers, camcorders, and digital cameras, the development of battery technology has become extremely important. Additionally, chargeable / dischargeable secondary batteries have become essential power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc., in efforts to solve air pollution caused by existing combustion engine vehicles using fossil fuels and reduce carbon dioxide emissions. Accordingly, there is an increasing demand for improvements to secondary batteries.

[0003] Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries have attracted attention for various advantageous characteristics: for example, they exhibit almost no memory effect compared to nickel-based secondary batteries, can thus be freely charged and discharged, and have a very low self-discharge rate and high energy density.

[0004] Secondary batteries can be classified based on the shape of the battery case into cylindrical batteries having an electrode assembly mounted in a cylindrical metal can, prismatic batteries having an electrode assembly mounted in a prismatic metal can, and pouch-type batteries. A pouch-type secondary battery generally accommodates an electrode assembly having a structure in which electrodes and separators are alternately arranged in a pouch-shaped case made of a laminated aluminum sheet.

[0005] Furthermore, secondary batteries can be classified based on their structure in which cathodes and anodes are stacked with a separator interposed between them. Typically, there can be a stacked structure in which multiple cathodes and anodes, cut to a predetermined unit size, are sequentially stacked with a separator interposed between the cathode and anode. In recent years, stacked / folded electrode assemblies have been developed to solve problems caused by jelly-roll type electrode assemblies and stacked type electrode assemblies, which are a combination of jelly-roll type and stacked type electrode assemblies. Such stacked electrode assemblies may also be called electrode stack assemblies.

[0006] With respect to Figures 1 to 4, the manufacturing method of a pouch-type secondary battery may include a molding process in which a portion of the film (pouch film) 1000 is formed to provide a cup 1005 (or housing space 1005) that surrounds a recess corresponding to a surface area of ​​the electrode assembly 1010. In particular, the molding process may include a step of press-molding the pouch film to form a cup in the film.

[0007] With respect to Figure 1, the pouch molding apparatus 300 generally includes an upper die 301 and a lower die 302. The upper die 301 and the lower die 302 may be operable to move toward and toward each other (for example, toward and toward each other). Specifically, the lower die 302 may be operable to move toward and toward the upper die 301, and / or the upper die 301 may be operable to move toward and toward the lower die 302. Alternatively or additionally, at least one of the upper die 301 and the lower die 302 may not move during pouch molding (i.e., during operation of the apparatus 300).

[0008] The apparatus 300 may include a die portion 304 that is operably coupled to a lower die 302. Initially, the die portion 304 may be located below the lower die 302 and / or at the lower end of the lower die 302. For example, the lower die 302 may include side walls (not shown in Figure 1) surrounding the upper surface 303, and the die portion 304 may be at least partially enclosed by the side walls of the lower die 302. During operation, the die portion 304 may be at least partially fastened to the side walls of the lower die 302. The die portion 304 may include a base portion 305 and a projection 306 extending upward from the base portion 305 (i.e., toward the upper die 301). The projection 306 of the die portion 304 may terminate at a tip portion 307. The projection 306 may be in the shape of a vertical wall having a linear shape in a plan view (e.g., when viewed from the upper die 301). The cross-section of the protruding portion 306 may be as shown in Figure 1, while any other preferred shape may be considered, as will be discussed in detail below.

[0009] The lower die 302 may include an upper surface 303, which may also be referred to as a support surface 303. The upper surface 303 may be a flat surface for supporting an initially flat pouch film. The portion of the lower die 302 that may include the upper surface 303 may also be referred to as an anvil 303. The lower die 302 may include a gap 308 provided in the upper surface 303 to allow the peak 307 and a portion of the protruding portion 306 of the die portion 304 to protrude through it. The gap 308 may have the shape of a linear slit in a plan view. The lower die 302 may be molded in such a way to provide a hollow space H below the upper surface 303. The die portion 304 may be at least partially located inside the hollow space H. For example, upward movement of the die portion 304 during operation may be restricted by the lower surface (rear surface) of the anvil 303. Needless to say, upward movement of the die portion 304 may be stopped before reaching the lower surface of the anvil 303.

[0010] The apparatus 300 may further include a punch 309 and a stripper portion 310. The punch 309 and / or stripper portion 310 may be operably coupled to the upper die 301. The punch 309 may have a shape formed by cup portions 1005 (also see Figure 2; also referred to herein as cups or concave cups) formed in the pouch. In particular, the punch 309 may be configured to provide two or more (three, four or more) cup portions in the pouch. For example, the punch 309 may include one or more larger body portions corresponding to the shape and size of each cup portion formed in the pouch. A bridge portion 1006 remains between the two cup portions 1005. The bridge portion 1006 is formed by a protruding portion 306 of the die portion 304.

[0011] For example, the stripper portion 310 and / or the punch 309 may be operable to move relative to the upper die 301. The punch 309 may be operable to move relative to the anvil 303 (i.e., toward and / or away from the anvil 303). The movement of the punch 309 may be indicated by arrow C in Figure 1. Additionally or alternatively, the die portion 304 may be operable to move relative to the upper die 301 (i.e., toward and / or away from the upper die 301). The movement of the die portion 304 may be indicated by arrow D in Figure 1.

[0012] During the operation of the apparatus 300 and / or in the corresponding method of forming a pouch, the pouch film (initially flat pouch film) 1000 may be positioned on the upper surface 303 of the lower die 302. The die portion 304 may be moved upward (e.g., rising towards the upper die 301) so that the tip portion 307 and part of the protruding portion 306 protrude upward through the gap 308 and thus enlarge the corresponding portion of the pouch film 1000. In some examples, the die portion 304 may be moved so that the tip portion 307 contacts the stripper plate 310 (until it does). Specifically, the protruding portion 306 may be extended between the punches 309 and fasten the stripper portion 310. Typically, the tip portion 307 of the protruding portion 306 has an essentially semicircular cross-sectional shape and thus forms a bridge portion 1006 with a corresponding semicircular tip.

[0013] The punch 309 can be moved downward to pressurize the pouch film 1000 (for example, downward toward the lower die 302). Thus, the initially flat pouch film 1000 can be drawn (stretched) according to the shape of the die's tip portion 307, protruding portion 306, and punch 309. Specifically, cup portions can be formed in the pouch according to the shape of the punch 309. A bridge portion can be formed in the pouch between the two cup portions, according to the shape of the protruding portion 306 and tip portion 307 in combination with the punch 309. The movement of the die portion 304 and punch 309 can be done simultaneously or later. Thus, referring to Figures 2 to 4, a pouch 1002 having at least two cup portions 1005 and a bridge portion 1006 between them is formed by pressurizing the initially flat pouch film 1000.

[0014] To release the pouch from the apparatus 300, the punch 309 may be moved upward (i.e., away from the lower die 302), and the die portion may be moved downward (i.e., away from the upper die 301). The stripper portion 310 may be moved to facilitate the removal of the pouch from the apparatus 300, for example, by reducing the contact area between the portion of the apparatus 300 and the pouch. For example, the stripper portion 310 may be moved together with the punch 309 (upward and / or downward). Alternatively, the stripper portion 310 may be moved upward after a short delay following the upward movement of the punch 309. The stripper portion 310 may also be moved downward first and then upward.

[0015] The pouch film 1000 may be supplied (initially) as a flat sheet. The pouch film 1000 may be plastic press-molded in the manner described herein. The pouch film 1000 may have a laminated structure comprising, for example, a metal film and one or more layers of synthetic material. For example, the metal film may be made of aluminum (Al), iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), zinc (Zn), or a combination thereof, or an alloy thereof. For example, one layer of synthetic material, or each of the layers of synthetic material, may be made of or contain polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene), benzobisoxazole, polyarylate, Teflon®, glass fiber, or a combination thereof.

[0016] As will be discussed in detail below, the protruding portion 306 is used to form a bridge portion between the two cup portions of the pouch. Thus, the protruding portion 306 may hereafter be referred to as the partition wall 306. The tip portion 307 of the die portion 304 is configured to design the upper portion of the bridge portion of the pouch film and may be specifically formed and molded. The tip portion 307 may hereafter be referred to as the peak 307. Furthermore, the terms cup, concave cup, and cup portion may be used interchangeably unless otherwise indicated or technically inappropriate.

[0017] Subsequently, the electrode assembly (also referred to as the electrode stack) 1010 is housed in one of the cup portions 1005. The electrode assembly may include layers of positive electrodes, negative electrodes, and separators stacked on top of each other in an alternating and repeating manner. The film 1000 is then folded against the bridge portion 1006 so that the cups 1005 face each other to form a pouch 1002 (Figure 3). To close the pouch-type secondary battery 1001, the side portions 1003 of the sheet surrounding the opposing cups 1005 are attached to each other along the sealing portion 1004 (Figure 4).

[0018] In an ideal scenario, the bridge portion 1006 can fully unfold during the folding of the pouch film 1000 so that the resulting pouch 1005 has substantially flat sidewalls where the bridge portion 1006 was (not shown). However, it is possible that the bridge portion 1006 may not fully unfold due to the rigidity of the material of the pouch film 1000. Thus, a portion of the bridge portion 1006 may remain by folding the pouch film 1000, which protrudes (extends) inward, as shown in Figure 3. Such remaining portions of the bridge portion 1006 may come into contact with the electrode assembly housed in the pouch 1005 and further deform the electrode assembly. This can cause damage to the electrode assembly and short circuits, and in some cases, lead to battery defects, failures, and / or safety problems.

[0019] Furthermore, due to the height difference P between the area surrounding the cup 1005, which includes at least a portion of the side portion 1003 and has not undergone the molding and pressurizing process, and the cup 1005 that has undergone the molding process, so-called bat-ears 1007 may occur when the pouch is folded. Such bat-ears 1007 are portions that unnecessarily protrude or twist the outside of the battery case, causing an increase in useless space that does not contribute to the capacity of the secondary battery. As a result, the energy density of the secondary battery decreases. Also, the bat-ears 1007 cause inaccurate measurement of the overall width of the cell, raising the risk of cracking and complicating the assembly of the battery module. [Overview of the project] [Problems that the invention aims to solve]

[0020] The object of this disclosure is to provide a pouch-type battery case, a secondary battery, and a battery molding apparatus that overcome the problems of the prior art, in particular, prevent undesirable and potentially harmful deformation of the pouch film.

[0021] However, the problems that the embodiments of this disclosure seek to solve are not limited to the problems described above and can be extended in various ways within the scope of the technical ideas contained herein. [Means for solving the problem]

[0022] One or more problems known from the prior art are solved by the subject matter of the invention as defined in the independent claim. Specific embodiments are given by the features of the dependent claims.

[0023] As described above with reference to Figures 1, 2, and 4, some of the features and operations of the system and method for press-forming pouches can also be applied to the claimed invention and should be noted that for the sake of brevity of this description they will not be repeated below.

[0024] This disclosure relates to a pouch-type battery case configured to house an electrode assembly having a structure in which electrodes and separators are arranged alternately. Such an electrode assembly may be referred to as an electrode assembly. The pouch-type battery case according to this disclosure includes a pouch film, a first cup portion, a second cup portion, and a bridge portion.

[0025] The pouch film has a film thickness. The film thickness is preferably constant and / or continuous in the transverse direction of the film. The film thickness is preferably constant and / or continuous in the longitudinal direction of the film. The pouch film has a first surface configured to serve in particular as the internal surface of the pouch-type battery case, and a second surface configured to serve in particular as the external surface of the pouch-type battery case. The first surface can be coupled to an electrode assembly arranged to be placed inside the pouch-type battery case. The second surface can be coupled outward from the electrode assembly and selectively to the environment surrounding the secondary battery.

[0026] The pouch film may define a longitudinal direction of the film and a transverse direction of the film. Before being formed into a pouch-type battery case, the pouch film may resemble a web, which defines a generally planar extension having the longitudinal direction of the film that may correspond to the transport direction of the pouch film in a forming apparatus, and the transverse direction of the film disposed perpendicular to the longitudinal direction of the film. The extension of the pouch film in the web direction or the longitudinal direction of the film may be substantially greater than the extension in the transverse direction of the film. For example, the extension in the transverse direction of the film may be 10 mm to 500 mm, for example 50 mm to 100 mm, and the extension of the pouch film in the longitudinal direction may be even larger. In the longitudinal direction, the pouch film may be designed to be separated into individual sections to form a web-like or "infinite" extension before being fixed in a pouch-type secondary battery. The film thickness extends perpendicularly to both the longitudinal direction of the film and the transverse direction of the film. The film thickness may be at least 100 times, particularly at least 1000 times, smaller than the smaller of the extension of the pouch film in the transverse direction of the film or the longitudinal direction of the film.

[0027] A first cup portion is formed in the pouch film having a concave shape directed from the first surface toward the second surface. A second cup portion is formed in the pouch film having a concave shape directed from the first surface toward the second surface. Under simple conditions, when the pouch film is formed into a pouch using, for example, a deep drawing apparatus described below, the pouch film may be arranged between a punch and a die such that the downward movement of the punch relative to the die forms a downwardly protruding cup portion. It will be clear that, as used herein, the term "downward" is generally understood to refer to a first direction. The first direction is the direction in which relative movement of the punch occurs relative to the die for deep drawing the pouch film to form the cup portion, where the die may be fixed and the punch moves downward, or the punch may be fixed and the die moves upward (in a second direction opposite the first direction), or the die may be moved in the second direction toward the punch and the punch may be moved in the first direction toward the die.

[0028] The bridge portion is formed in the pouch film between the first cup portion and the second cup portion. The bridge portion connects the first cup portion to the second cup portion. Preferably, the bridge portion is positioned in the lateral film direction between the first cup portion and the second cup portion. The bridge portion preferably extends laterally across the film. The first cup portion and the second cup portion are selectively substantially the same size and shape. The first cup portion has a first cup depth, and the second cup portion has a second cup depth. The first cup depth and / or second cup depth are preferably greater than the film thickness. The first cup depth and / or second cup depth may preferably be at least 10 times, particularly at least 100 times, the film thickness. The lateral extension of the pouch film may be at least 5 times, particularly at least 10 times, preferably at least 20 times, the first cup depth and / or second cup depth. The first cup depth and / or second cup depth are preferably adapted to the height of the electrode assembly. In particular, the first cup portion is configured to accommodate a first portion of an electrode assembly housed or to be housed within a battery case. The first portion of the electrode assembly may be at least 1 / 4, at least 1 / 3, or at least 1 / 2 of the electrode stack forming the electrode assembly. Alternatively or additionally, the second cup portion is configured to accommodate a second portion of an electrode assembly housed or to be housed within a battery case. The second portion of the electrode assembly may be at least 1 / 4, at least 1 / 3, or at least 1 / 2 of the electrode stack forming the electrode assembly. The first and second cup portions may preferably be arranged symmetrically with respect to each other, with a bridge portion between them. The length of the bridge portion in the transverse direction of the film (bridge portion length) may preferably correspond to the length of the first cup and / or the second cup length in the transverse direction of the film. The bridge portion may preferably terminate within the first side portion on one transverse side and within the second side portion of the pouch film on the opposite side.

[0029] According to the first aspect of the pouch-type battery case according to the present disclosure, the bridge portion includes a notch formed on the first surface protruding toward the second surface. The bridge portion and / or the notch may be curved. The curvature of the notch preferably opposes the curvature of the bridge portion. The pouch film may in some cases preferably be continuously curved from the first cup portion to the second cup portion, and the curvature of the notch is bent in a direction opposite to the curvature of the remaining bridge portion. The notch may be configured to extend continuously in the lateral direction of the film. The notch may have a notch length corresponding to the length of the bridge portion. The notch length may extend, particularly continuously, from a first side portion of the battery case adjacent to the first cup portion and / or the second cup portion to a second side portion of the battery case adjacent to the first cup portion and / or the second cup portion, wherein the first side portion and the second side portion are arranged opposite to each other in the lateral direction of the film.

[0030] Advantageously, the notch can function in a hinge-like manner when the first cup portion and the second cup portion are folded towards each other to form a pouch for accommodating a battery assembly. By providing the notch in the bridge portion, a more clearly defined pouch-type secondary battery can be formed compared to prior art designs. Providing the notch prevents the peak of the bridge portion from colliding with the electrode assembly, thereby reducing the risk of deforming and / or damaging the anode, cathode and separator. Furthermore, it has been found that providing a notch in the bridge portion results in a considerable reduction in the formation of butt ears. Therefore, it is possible to increase energy density, improve cell dimensional stability, prevent the risk of cracks, and facilitate the assembly of battery modules.

[0031] In one embodiment of the pouch-type battery case, the notch has a notch depth smaller than the film thickness, particularly less than half the film thickness. The notch depth may be at least 1 / 10 of the film thickness, preferably at least 1 / 4 of the film thickness. The notch depth may be at least 10 μm, particularly at least 25 μm, preferably at least 50 μm, and more preferably at least 100 μm. Alternatively or additionally, the notch depth may be 200 μm or less, particularly 180 μm or less, and preferably 150 μm or less. The notch depth is preferably constant in the transverse direction of the film with respect to at least 50% of the notch length, particularly at least 75% of the length, preferably at least 90% of the length, or at least 95% of the notch length. By providing such a depth to the notch, the pouch-type battery case may have improved folding characteristics while maintaining the structural integrity of the pouch film in the bridge portion area. On the other hand, it has been shown that notch depths that extend considerably beyond the film thickness may indicate cracking or other weakening of the pouch film, which can result in reduced durability of the battery case.

[0032] In other embodiments of pouch-type battery cases that can be combined with those described above, the notch has a notch width that extends longitudinally along the film between two vertices of the pouch film adjacent to the notch. The vertices may be on the peak level of the inner surface of the bridge portion. Alternatively or additionally, the vertices may be on the level of the inner surface surrounding the cup portion, in particular on the level of the plane defined by the side portion.

[0033] The notch width is at least half the film thickness, and more particularly at least 1. Alternatively or additionally, the notch width may be 3 times or less the film thickness, and more particularly 2 times or less. The notch depth may be at least 50 μm, more particularly at least 100 μm, and preferably at least 250 μm. Alternatively or additionally, the notch depth may be 2 mm or less, more particularly 1.5 mm or less, and preferably 1 mm or less. The notch width is preferably constant in the transverse direction of the film for at least 30% or at least 50% of the notch length, more particularly at least 75% of the length, preferably at least 90% of the length, or at least 95% of the notch length.

[0034] In an additional embodiment of a pouch-type battery case that can be combined with the above, the bridge portion defines the width of the bridge portion extending from the first cup portion to the second cup portion. The width of the bridge portion corresponds to the distance from the first cup portion to the second cup portion. The width of the bridge portion is preferably constant in the lateral direction. The width of the bridge portion is preferably defined by the distance from the inner surface of the first peripheral portion of the first cup portion to the inner surface of the first peripheral portion of the second cup portion. After molding (or: drawing) and before folding, the first peripheral portions of the first cup portion and the second cup portion form opposing legs of a bridge portion having opposing outer surfaces. In particular, the width of the bridge portion is at least 4 times, preferably at least 6 times, the film thickness. Alternatively or additionally, the width of the bridge portion may be no more than 20 times, particularly no more than 10 times, the film thickness. In particular, the radius of curvature of the notch is at least as large as, preferably larger than, the radius of curvature of the vertex of the bridge portion adjacent to the notch. The bridge width may be at least 0.5 mm, particularly at least 0.75 mm, preferably at least 1 mm, and / or 5 mm or less, particularly 2 mm or less, preferably 1.5 mm or less. By adapting the bridge width and notch width to each other as described above, the folding deformation can be controlled so as to minimize the formation of undesirable wrinkles, butt ears, or protrusions that pose a risk of collision with the electrode assemblies housed therein.

[0035] In one embodiment of a pouch-type battery case that can be combined with the above-described configuration, the bridge portion (including the notch) has an M-shaped cross-section in the longitudinal direction of the film. The M-shaped cross-section of the bridge portion is preferably constant and / or continuous along the length of the bridge portion in the transverse direction of the film. The M-shape of the bridge portion may persist in the transverse direction of the film for at least 50% of the notch length, particularly for at least 75% of the length, preferably for at least 90% of the length, or for at least 95% of the length of the bridge portion.

[0036] According to one embodiment of a pouch-type battery case according to the first aspect of the present disclosure, and optionally one or more of its embodiments described herein, and / or the second aspect of the present disclosure, and optionally one or more of its embodiments described herein, the pouch film has a pouch film thickness of 100 μm to 250 μm, particularly 160 μm to 200 μm, preferably 175 μm to 190 μm. Preferably, the pouch film includes a gas barrier layer made of metal. The metal of the gas barrier layer of the pouch film preferably includes or consists of aluminum and / or an aluminum-containing alloy, particularly aluminum alloys of alloy number AA80XX series. The alloy number of the aluminum alloy may be AA8021. The aluminum alloy may contain about 1.3 wt% to about 1.7 wt% iron and about 0.2 wt% or less silicon, and may have a grain size of about 10 μm to about 13 μm. The thickness of the gas barrier layer may be 30 μm to 150 μm, particularly 70 μm to 120 μm, preferably 80 μm to 100 μm. The pouch film may further include a sealant layer, preferably formed as the innermost layer, made from the first polymer. The thickness of the sealant layer may be 60 μm to 100 μm. Additionally or alternatively, the pouch film may include a surface protection layer, preferably formed as the outermost layer, made from the second polymer. The first polymer may be the same as or different from the second polymer. In particular, the gas barrier layer is laminated between the surface protection layer and the sealant layer. The pouch film may further include a drawing aid layer, made from the third polymer. The third polymer may be the same as or different from the first polymer and / or the second polymer. The drawing aid layer may be laminated between the surface protection layer and the gas barrier layer. The thickness of the drawing aid layer can range from 10 μm to 75 μm, and particularly from 20 μm to 50 μm.

[0037] The first polymer can be made from one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylenebenzobisoxazole), polyarylate, Teflon®, and glass fibers. In particular, polyolefin resins such as polypropylene (PP) or polyethylene (PE) can be the main components in the first polymer. Polypropylene (PP) offers excellent mechanical properties including tensile strength, stiffness, surface hardness, abrasion resistance, and thermal resistance, as well as excellent chemical properties including corrosion resistance, and therefore can be selected as the main component of the sealant layer.

[0038] The second polymer can be manufactured from one or more of the following: polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylenebenzobisoxazole), polyarylate, Teflon®, and glass fibers. It may be advantageous to primarily use polymers with desirable abrasion resistance and thermal resistance, such as polyethylene terephthalate (PET).

[0039] The third polymer can be made from one or more of the following: polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylenebenzobisoxazole), polyarylate, Teflon®, and glass fiber. In particular, nylon resin can be readily bonded to polyethylene terephthalate (PET) in the surface protective layer and can exhibit a similar effect to aluminum alloy in the moisture barrier layer during and after the drawing process. Therefore, nylon resin can be used as the main component of the third polymer.

[0040] In a second aspect of this disclosure, the disclosure relates to a pouch-type battery case configured to house an electrode assembly having a structure in which electrodes and separators are arranged alternately. Such an electrode assembly may be referred to as an electrode assembly. The pouch-type battery case according to this disclosure includes a pouch film, a first cup portion, a second cup portion, and a bridge portion.

[0041] According to a first embodiment of the present disclosure, and a second embodiment of the present disclosure which may be selectively combined with at least one of its embodiments, a first cup portion separates a second cup portion from the longitudinal portion of the film, and a bridge portion extending laterally from the film includes a central bridge section positioned laterally between two lateral bridge sections, the central bridge section being offset from the lateral bridge sections toward a second surface. The length of the bridge portion laterally from the film (bridge portion length) may preferably correspond to the length of the first cup and / or the second cup length laterally from the film. The bridge portion may preferably terminate laterally within the first side portion on one side and within the second side portion of the pouch film on the opposite side. Cup portions adjacent to the bridge portion have their respective cup depths. The cup depth of the first cup portion may preferably be the same as the cup depth of the second cup portion. The cup depth of each cup portion, preferably a constant cup depth, is defined by the depth of the punch fastening into the die. The offset from the lateral bridge section to the central bridge section may be at least 50 μm, particularly at least 100 μm, preferably at least 150 μm, and / or 500 μm or less, particularly 300 μm or less, preferably 250 μm or less. The offset from the lateral bridge section to the central bridge section may be at least 0.5 times the thickness of the pouch film, particularly at least 0.75 times, preferably at least 1 time, and / or 2 times or less, particularly 1.5 times or less, preferably 1.25 times or less. By providing an offset between the lateral sections to the central section of the bridge portion, the undesirable formation of butt ears can be significantly reduced. It has also been shown that providing a downwardly offset central bridge section results in a substantial reduction in collisions between the folded bridge portion and the electrode assembly placed in the battery pouch.

[0042] In one embodiment of a second form of the pouch-type battery case, the lateral bridge section is on the same level as the internal surface surrounding the cup portion, and is on the level of a plane defined by the internal surface surrounding the first cup portion and / or the second cup portion, particularly the lateral portion positioned laterally adjacent to the cup portion.

[0043] In an additional embodiment of the second form of the pouch-type battery case, the central section has a first length and the lateral sections each have a second length. The first and second lateral sections may have the same second length. In particular, the level of the lateral sections is constant along the second length. Alternatively or additionally, the level of the central bridge section is constant along the first length. The first length is preferably greater than the second length. In particular, the first length may be at least 10 mm, particularly at least 20 mm, preferably at least 50 mm, and / or 200 mm or less, particularly 150 mm or less, preferably 100 mm or less. In particular, the first length is at least twice as large as the second length. In particular, the second length may be at least 2 mm, particularly at least 5 mm, preferably at least 7 mm, and / or 20 mm or less, particularly 15 mm or less, preferably 12 mm or less.

[0044] According to another embodiment of the second form of the pouch-type battery case, which can be combined with the above-described version, the bridge section further includes inclined sections connecting the central section and the lateral sections. A first inclined section may be positioned between the first lateral bridge section and the central bridge section, and a second inclined section may be positioned between the central bridge section and the second lateral bridge section. The inclined sections gradually change the level of the bridge section from the central bridge section to the raised level of the lateral bridge sections. The inclined sections are particularly continuous, constant, and have a linear incline. and / or may be formed at least partially or continuously as an arched slope. The length of the inclined sections is preferably the same. The length of the inclined sections is preferably less than the length of the central bridge section. The length of the inclined sections (third length) may be as long as or less than the length of the lateral bridge section. In particular, the third length may be at least 1 mm, particularly at least 3 mm, preferably at least 5 mm, and / or 12 mm or less, particularly 10 mm or less, preferably 8 mm or less. By providing such a slope between the lateral bridge sections that rise above the central bridge section, undesirable wrinkles or other deformations that may be difficult to control during the folding of the pouch film can be minimized or even completely avoided. Surprisingly, a considerable improvement in the control of folding deformation was perceived when both the first and second embodiments of this disclosure were realized as pouch-type battery cases.

[0045] A third aspect of the present disclosure provides a secondary battery comprising at least one of the first and / or second aspects of the present disclosure and optionally a battery case according to that embodiment. In the secondary battery, a first cup portion and a second cup portion directly face each other to form a pouch. Furthermore, an electrode assembly is housed within the pouch. Preferably, the secondary battery is formed by folding the pouch film against a notch at the bridge portion. In the secondary battery, the side portions adjacent to the first cup portion on one side and the second cup portion on the other side are fastened to each other, preferably sealed and attached to each other. Furthermore, sealing portions of the pouch film adjacent to the first cup portion or the second cup portion, respectively, and positioned opposite the bridge portion relative to the cup portion, are fastened to each other, preferably sealed and attached to each other. The first peripheral portions of the first cup portion and the second cup portion (facing each other before the folding of the pouch film against the bridge portion) may form a substantially flat lower end surface of the pouch-type secondary battery.

[0046] The pouch, which is the case for a pouch-type rechargeable battery, can be manufactured by forming two cup portions on a flexible pouch film by a pressing process. After the cup portions are formed, the electrode assembly is then housed in one of the cup portions, and its sides are sealed. This completes the manufacturing of the rechargeable battery.

[0047] Draw forming, as an example of a press forming process, can be carried out in the following manner: the pouch film is inserted into a forming device such as a press machine, as described below; and the pouch film is pressed and drawn by a punch and / or die. The pouch film is manufactured in multiple layers, with a moisture barrier layer located in the inner layers being formed of metal.

[0048] This disclosure also relates to a battery case molding apparatus for manufacturing a pouch-type battery case, preferably according to the first embodiment of this disclosure, as described above. The battery case molding apparatus includes a die, a punch, and a stripper section.

[0049] The die has an upper surface on which the pouch film is placed, and includes two recessed molding spaces and a partition wall separating the molding spaces. The molding spaces are preferably adapted to form a first cup portion and a second cup portion.

[0050] The punch is positioned above the molding space. The punch includes two punch pads. Specifically, the first punch pad corresponds to the first molding space for forming the first cup portion, and the second punch pad corresponds to the second molding space for forming the second cup portion. The punch is operable to lower the punch pads to insert the pouch film, positioned on the upper surface, into the molding space.

[0051] The die may be configured such that a portion of the pouch film positioned in the protruding area of ​​the molding space is offset by the punch to form a cup section. Additionally, the die may be configured such that a portion of the pouch film positioned on the solid section of the upper surface of the die adjacent to the protruding area of ​​the molding space and the partition wall forms a side portion and / or a sealing portion, and / or preferably remains at a first level.

[0052] The stripper portion works in cooperation with the punch and is positioned between the punch pads. Preferably, the stripper portion is positioned opposite the partition wall. Preferably, the stripper portion is configured to work in cooperation with the partition wall to form a bridge portion for the pouch-type battery case within the pouch film.

[0053] According to a third aspect of the present disclosure, the stripper portion includes a projection configured to form a notch within the pouch film, and the partition wall includes a fold facing the projection to accommodate a portion of the pouch film, particularly the portion of the pouch film displaced by the projection. The fold and the projection are preferably formed complementaryly. The die and the punch are preferably adapted to accommodate the pouch film between them when the punch descends into the die. Additionally or alternatively, the projection and the fold are adapted to accommodate the pouch film between them when the punch descends into the die. When the punch descends into the die, the die and the punch may be adapted to maintain a distance from each other corresponding to the thickness of the pouch film being formed. Alternatively or additionally, when the punch descends into the die, the stripper portion including the projection and the die including the fold may be adapted to maintain a distance from each other corresponding to the thickness of the pouch film being formed.

[0054] In an additional development of a battery case molding apparatus according to a third aspect of this disclosure, the protrusion has a protrusion height, which is less than the film thickness of the pouch film being molded. In particular, the protrusion height is less than half the film thickness or at least 1 / 10 of the film thickness. Alternatively or additionally, the wrinkle has a wrinkle depth, which is less than the film thickness of the pouch film being molded. In particular, the wrinkle depth is less than half the film thickness or at least 1 / 10 of the film thickness. The wrinkle depth corresponds to, and preferably is the same as, the protrusion height.

[0055] In one embodiment of a battery case molding apparatus that can be combined with previous ones, wrinkles define a wrinkle width extending between adjacent shoulders of a partition wall. The partition wall has a wall thickness defined between two molding spaces. The wall thickness is at least 1.1 times greater than the wrinkle width, and particularly at least 1.25 times greater than the wrinkle width. Alternatively or additionally, the wall thickness is no more than 2 times the wrinkle width, and particularly no more than 1.5 times the wrinkle width. In particular, the wall thickness is greater than the film thickness of the pouch film being molded. Preferably, the wall thickness is at least 2 times greater than the film thickness, preferably at least 4 times greater. Alternatively or additionally, the wall thickness is no more than 10 times the thickness, and particularly no more than 6 times the film thickness of the pouch film being drawn in the apparatus. The wall thickness may be at least 0.3 mm, particularly at least 0.5 mm, preferably at least 0.75 mm or more, and / or 4 mm or less, particularly 1.5 mm or less, preferably 1.25 mm or less.

[0056] In other embodiments of the battery case molding apparatus that can be combined with the previous ones, the projection has a projection width between adjacent planar flanks of the stripper portion. The projection width is greater than the projection height. In particular, the projection width is at least 1.25 times, preferably at least 1.5 times, the projection height. Alternatively or additionally, the projection width is no more than 3 times, preferably no more than 2 times, the projection height. Preferably, the projection has a cosine cross-section.

[0057] This disclosure also relates to a battery case molding apparatus for manufacturing a pouch-type battery case, preferably according to a second embodiment of the disclosure, as described above. The battery case molding apparatus includes a die, a punch, and a stripper section.

[0058] The die has an upper surface on which the pouch film is placed, and includes two recessed molding spaces and a partition wall separating the molding spaces. The molding spaces are preferably adapted to form a first cup portion and a second cup portion.

[0059] The punch is positioned above the molding space. The punch includes two punch pads. Specifically, the first punch pad corresponds to the first molding space for forming the first cup portion, and the second punch pad corresponds to the second molding space for forming the second cup portion. The punch is operable to lower the punch pads in order to insert the pouch film, positioned on the upper surface, into the molding space.

[0060] The die may be configured such that a portion of the pouch film positioned in the protruding area of ​​the molding space is offset by the punch to form a cup section. Additionally, the die may be configured such that a portion of the pouch film positioned on the solid section of the upper surface of the die adjacent to the protruding area of ​​the molding space and the partition wall forms a side portion and / or a sealing portion, and / or preferably remains at a first level.

[0061] The stripper portion works in cooperation with the punch and is positioned between the punch pads. Preferably, the stripper portion is positioned opposite the partition wall. Preferably, the stripper portion is configured to work in cooperation with the partition wall to form a bridge portion for the pouch-type battery case within the pouch film.

[0062] According to a third embodiment and a fourth embodiment of the present disclosure which can be combined with its embodiments, the partition wall is positioned laterally between the molding spaces. The partition wall includes a central wall section positioned laterally between two lateral wall sections. The central wall section is offset relative to the lateral wall sections in the direction in which the punch pad descends. The offset from the lateral wall section to the central wall section may be at least 50 μm, particularly at least 100 μm, preferably at least 150 μm, and / or 500 μm or less, particularly 300 μm or less, preferably 250 μm or less. The offset from the lateral wall section to the central wall section may be at least 0.5 times, particularly at least 0.75 times, preferably at least 1 time, and / or 2 times or less, particularly 1.5 times or less, preferably 1.25 times or less of the thickness of the pouch film being drawn in the apparatus.

[0063] According to one embodiment of the fourth aspect, the stripper portion and / or punch has a lug portion. The lug portion is preferably formed complementary to the partition wall. The lug portion is positioned between the punch pads. The lug portion includes a central lug section positioned laterally between the lateral lug sections, the central lug section protruding to be introduced into the recessed portion of the die provided by the central wall section. [Effects of the Invention]

[0064] According to the embodiment, a more clearly defined pouch-type secondary battery can be molded compared to the prior art design, avoiding collisions between the electrode assembly and the bridge portion, thereby reducing the risk of deformation and / or damage to the anode, cathode, and separator. Furthermore, a considerable reduction in butt-ear formation can be achieved according to the embodiment. Thus, it is possible to improve energy density, enhance the dimensional stability of the cell, prevent the risk of cracking, and facilitate the assembly of the battery module.

[0065] The effects of this disclosure are not limited to those described above, and any additional effects not mentioned above may be clearly understood by those skilled in the art from the descriptions of the claims appended. [Brief explanation of the drawing]

[0066] [Figure 1] This is a schematic cross-sectional view of an apparatus for forming a secondary battery. [Figure 2] This is a schematic side view of a battery case for a pouch-type rechargeable battery. [Figure 3] This is a schematic cross-sectional view of a pouch-type rechargeable battery. [Figure 4] This is another drawing of a pouch-type rechargeable battery. [Figure 5] This is a schematic exploded view of the battery case and electrode assembly for a pouch-type secondary battery, as an example. [Figure 6] This is a schematic cross-sectional view of a battery case, an example in which an electrode assembly is housed. [Figure 7] This is a schematic side view of a battery case for a pouch-type rechargeable battery, as an example. [Figure 8] This is a schematic cross-sectional view of a pouch-type secondary battery, as an example. [Figure 9] This is a schematic detail diagram of the bridge portion of a pouch-type secondary battery between the partition wall and the stripper portion of an example of a device. [Figure 10] This is another schematic cross-sectional view of a pouch-type secondary battery, as an example. [Figure 11] This is a schematic cross-sectional view of an apparatus for forming a secondary battery, as an example. [Figure 12] This is another schematic detail diagram of the bridge portion of the pouch-type secondary battery between the partition wall and the stripper portion of the device, as an example. [Figure 13] This is a detailed diagram showing the fastening between the partition wall and the pouch film inside the device, as an example. [Figure 14] This is a detailed diagram showing the fastening between the stripper portion and the pouch film within an example of the device. [Modes for carrying out the invention]

[0067] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily perform them. The present disclosure can be modified in a variety of different ways and is not limited to the embodiments presented herein.

[0068] Parts irrelevant to the description have been omitted in order to clearly illustrate this disclosure, and similar reference numbers refer to similar elements throughout the description.

[0069] In addition, the size and thickness of each element are shown arbitrarily in the drawings for illustrative purposes, and this disclosure is not necessarily limited to those shown in the drawings. In the drawings, the thickness of layers, regions, etc., is exaggerated for clarity. In the drawings, the thickness of some layers and regions is exaggerated for illustrative purposes.

[0070] Additionally, when an element such as a layer, film, region, or plate is referred to as being "on top of" or "above" another element, it can be understood that it may also be directly above any other element or intervening element that may exist. In contrast, when an element is referred to as being "directly above" another element, it means that no other intervening element exists. Additionally, the words "on top of" or "above" mean positioned on or below the reference part, and do not necessarily mean positioned on the upper edge of the reference part in the opposite direction of gravity. On the other hand, when an element is described as being positioned "below" or "below" another part, as when it is described as being positioned "on top of" or "above" another part, it can also be understood by referring to the above.

[0071] Additionally, when a description refers to a part as "containing" or "consisting of" a particular component, it does not exclude other components unless otherwise explicitly stated, and the part may further contain other components.

[0072] Additionally, throughout the explanation, when "planar" is mentioned, it means when the target portion is viewed from the top side, and when "cross-section" is mentioned, it means when the target portion is viewed perpendicularly from the side of a cross-sectional cut.

[0073] The battery cases, pouch-type rechargeable batteries, and devices are described below with reference to the accompanying drawings. While the examples shown and described with reference to Figures 1-4 are intended to illustrate typical devices and common manufacturing methods, it should be noted that some features and operations of the systems and methods for press-forming pouches, as described above with reference to Figures 1-4, may also be embodied in embodiments, unless technically inappropriate. Such features and operations may not be explicitly repeated below for the sake of brevity of description.

[0074] The pouch-type battery relating to this disclosure is generally designated by reference number 10. A battery case for such a pouch-type battery assembly is generally designated by reference number 11. An apparatus for forming the pouch-type battery relating to this disclosure is generally designated by reference number 100.

[0075] Figure 5 shows an exploded view of the battery 10. The battery 10 may be a rechargeable battery, particularly a pouch-type rechargeable battery. The battery 10 includes a battery case 11. An exemplary electrode assembly 21 housed in the battery case 11 is further shown in Figure 5. Figure 6 shows a schematic cross-sectional view of the battery case 11 including the electrode assembly 21.

[0076] The battery case 11 may be formed, for example, by press-molding the pouch film 1 in a manner similar to that described above, with reference to Figures 1 to 4. In Figures 5 and 6, the battery case 11 includes a first case section 18, a second case section 19, and a bridge portion 14 formed between them. The first case section may include a first cup portion 13 recessed in the thickness direction from the pouch film 1. The first cup portion 13 may have a tray shape having a rectangular shape in a plan view (i.e., in the thickness direction) with circular corners. The second case section 19 may include a second cup portion 15 recessed in the thickness direction from the pouch film 1. The second cup portion 15 may have a tray shape having a rectangular shape in a plan view (i.e., in the thickness direction) with circular corners. The first case section 18 and the second case section 19 are foldable or can be folded relative to the bridge portion 14. In particular, one of the first case section 18 and the second case section 19 can be folded over the other case section 18, 19 so that the first cup portion 13 and the second cup portion 15 can be placed on top of each other. A pouch for housing the electrode assembly 21 can be obtained in this manner.

[0077] The electrode assembly 21 includes electrodes 23 and 25, each having a sheet-like shape. The electrode assembly 21 can be prepared by stacking the electrodes 23 and 25 alternately, with a separator 24 interposed between adjacent electrodes 23 and 25.

[0078] As can be seen in Figure 5, the sheet-like electrodes 23 and 25 have electrode tabs 22 that project from the electrodes 23 and 25 onto opposing sides of the electrode assembly 21 in the lateral direction X. For example, the first electrode tab 22 projects from the first side of the electrode assembly 21 and may be operationally coupled to the negative electrode 23, and the second electrode tab 22 projects onto the second side of the electrode assembly 21 and may be operationally coupled to the positive electrode 25. The first and second sides of the electrode assembly 21 may face each other or refer to the same side of the electrode assembly 21 (not shown in the drawings). Each electrode tab 22 has an insulating portion 26 configured to be positioned between opposing side portions 16 of the battery case 11. The side portions 16 of the battery case 11 are attached to each other via the folding of the pouch film 1 (i.e., in the assembled state of the battery 10) to provide a fluid seal. Each electrode tab 22 is terminated with its respective electrode lead 27 for electrical coupling.

[0079] The pouch film 1 may be configured as described above with reference to Figures 1 to 4. In particular, the pouch film 1 may include any or all of the features described above with reference to the pouch film 1000 in Figures 1 to 4. The pouch film 1 may preferably include a metal layer made of aluminum or an aluminum alloy. Before undergoing press forming as described herein, the pouch film 1 may be substantially flat. In particular, the pouch film 1 may have a laminated structure including a number of layers laminated together. The pouch film 1 may preferably have a web-like shape. Before being processed into the electrode case 11, the pouch film 1 may have a constant and continuous film thickness d1 of 100 μm to 250 μm, or 150 μm to 200 μm, preferably 175 μm to 190 μm, or more preferably about 183 μm (e.g., 183 μm ± 10 μm). The width of the film in the transverse direction X (or width direction X) can range from several centimeters to several tens of centimeters, for example, 1 cm to 100 cm, or 2 cm to 50 cm, preferably 5 cm to 30 cm. The pouch film 1 can be extended considerably more than the film width in the web transport direction Y or longitudinal direction Y, especially several meters or more. For example, the length of the film in the longitudinal direction Y may be 5 cm to 500 cm, or 10 cm to 250 cm, or preferably 15 cm to 150 cm.

[0080] The battery case 11 is manufactured from a pouch film 1 as disclosed herein. The battery case 11 includes a first cup portion 13 and a second cup portion 15, which may preferably be manufactured by deep drawing in apparatus 100 as described herein. The cup portions 13 and 15 are formed adjacent to each other and may be separated by a bridge portion 14 between them.

[0081] The pouch film 1 has a first surface 31 and a second surface 32 opposite the first surface 31. For ease of reference, the first surface 31 may be referred to as the inner surface 31, and the second surface 32 may be referred to as the outer surface 32. With respect to the initially substantially flat shape of the pouch film 1, the cup portions 13, 15 (which may be formed by deep drawing and / or press molding) are offset in the direction from the first surface 31 toward the second surface 32, i.e., they are recessed (indented) in a downward direction D which may be parallel to the direction from the first surface 31 toward the second surface 32. The first surface 31 is positioned above the second surface 32 in the apparatus 100 described later with respect to Figures 11 and 12, and therefore may be referred to as the upper film surface 31 and the lower film surface 32.

[0082] The cup portions 13 and 15 are recessed, but the bridge portion 14 remains elevated. The bridge portion 14 may remain at least partially or completely on the plane of the pouch film 1 defined by the side portions 16 surrounding the cup portions 13 and 15. In some embodiments, the peak of the bridge portion 14 is positioned entirely on the plane defined by the side portions 16 adjacent to the cup portions 13 and 15 in the lateral direction X of the film. In some embodiments, the peak of the bridge portion 14 may be divided into a number of sections, some of which may be selectively positioned at the same level as the side portions 16, and at least some of which are offset (downward) from the first surface 31 toward the second surface 32. The offset s of the sections is less than the depths d13, d15 of the first cup portion 13 and / or the second cup portion 15, as described below with reference to Figure 10.

[0083] In some embodiments, the peak of the bridge portion 14 has a notch 41 formed in the bridge portion 14 for most or substantially all of its length in the transverse direction X of the film, as described below with reference to Figure 9, for example.

[0084] To form the pouch-type battery 10, the battery case 11 is folded against a bridge portion 14 between cup portions 13 and 15, as shown in Figure 6. In the illustrated embodiment, the bridge portion 14 has a notch 41 pressed into the first surface 31 of the film pouch. The notch 41 may provide a film joint from which a clearly defined folding motion of the pouch film can occur.

[0085] The pouch film 1 may be divided into a first case section 18 (or: first pouch section 18) and a second case section 19 (or: second pouch section 19), as described above. The first case section 18 and the second case section 19 may be symmetrical with respect to a plane passing through a bridge portion 14. The bridge portion 14 may separate the pouch film 1 into two mirror-symmetric case sections 18, 19. Each of the case sections 18, 19 includes one respective cup portion 13, 15. In this application, the (battery) case sections 18, 19 may also be referred to as pouch sections 18, 19. The first cup portion 13 and the second cup portion 15 may be the same or substantially the same shape and size. Since the electrode assembly 21 has a shape substantially similar to a regular hexahedron, the housing space for the electrode assembly 21 provided by the first cup portion 13 and the second cup portion 15 has a shape corresponding to a hexahedron electrode assembly. Therefore, the widths w13 and w15 of the cup portions 13 and 15 in the transverse direction X of the film may preferably be the same size. Also, the lengths l13 and l15 of the first cup portion 13 and the second cup portion 15 in the longitudinal direction Y of the film may be the same size. The widths w13 and w15 of the cup portions 13 and 15 extend along the transverse axis of the film between the opposing side portions 16 of the case 11, respectively. The lengths l13 and l15 of the first cup portion 13 or the second cup portion 15 extend along the longitudinal direction Y of the film between the opposing peripheral portions 12 of the respective cup portions 13 and 15. The peripheral portions 12 can connect the recessed lower ends of the cup portions 13 and 15 to the bridge portion 14 and, on the other hand, to the sealing portions 17 of the respective case sections 18 and 19. The peripheral portions 12 may generally be referred to as the side walls of the cup portions 13 and 15. The sum of the first depth d13 and the second depth d15 of the first cup portion 13 and the second cup portion 15 may correspond to the (stack) height h of the electrode assembly 21. As shown in the illustrated embodiment, the first depth d13 and the second depth d15 are the same or substantially the same. Alternatively, the first depth d13 may be greater than the second depth d15.

[0086] Figure 7 shows a schematic cross-sectional side view of the battery case 11. Figure 8 shows a schematic cross-sectional side view of the pouch-type secondary battery 10, including the folded battery case 11 shown in Figure 7, which houses the electrode assembly 21.

[0087] Figure 7 shows a cross-section of a pouch film 1 extending in the longitudinal direction Y of the film. The pouch film 1 is molded to include a first cup portion 13, a second cup portion 15, and a bridge portion 14 between them. In the longitudinal direction Y of the film, which can correspond to the direction of movement of the pouch film 1 via the apparatus 100, both cup portions 13 and 15 have their respective adjacent degassing or sealing portions 17. Thus, each of the cup portions 13 or 15 is positioned in the longitudinal direction Y of the film between the bridge portion and its respective sealing portion 17. In the longitudinal direction Y of the film, both cup portions 13 and 15 are confined between opposing peripheral portions 12 (which may form the side walls of the respective cup portions 13 and 15). The first peripheral portion 12 may form the opposing legs of the bridge portion 14. The second peripheral portion 12 may connect the lower ends of the cup portions 13 and 15 to the sealing portion 17. The peripheral portion 12 may have an extension in the downward direction D corresponding to the depths d13 / d15 of the respective cup portions 13 and 15. In the lateral direction X of the film, corresponding to the viewing direction for the illustration in Figure 7, the cup portions 13 and 15 are confined by the respective side portions 16. The side portions 16 and sealing portions 17 of the pouch film 1 can maintain their level during the molding of the pouch film 1 (e.g., press molding and / or folding), particularly when the cup portions 13 and 15 sink out of the pouch film 1, especially when using the apparatus 100 as described later.

[0088] The tip or peak of the bridge portion 14 has a notch 41, so that the bridge portion 14 has a shape similar to M in cross-sectional view. Preferably, the pouch film 1 is continuously curved along the path from the first cup portion 13 to the second cup portion 15. Thus, the bridge portion 14 may be continuously curved. The bridge portion 14 includes a centrally located notch 41. In the area of ​​the notch 41, the pouch film is continuously curved, preferably in an arc projecting downward (or outward). On each side of the notch 41 in the longitudinal direction Y of the film, vertices 46, 47 may be formed, which will be described in more detail below with respect to Figure 9. The vertices 46 and 47 preferably form continuously curved arcs projecting upward (or inward).

[0089] As shown in Figure 8, thanks to the notch 41 and the provision of the inner surface 31 and the center of the bridge portion 14 in the pouch film 1, the second cup portion 15 can be easily and accurately folded onto the first cup portion 13 to form a pouch for housing the electrode assembly 21 (and vice versa). The notch 41 in the bridge portion 14 defines the axis of rotation from which the pouch film 1 is folded, thereby avoiding undesirable deformation of the pouch film 1, particularly in the area of ​​the side portion 16, and the occurrence of bridge peaks that perforate the electrode assembly 21.

[0090] Figure 9 shows a detailed view of the pouch film 1 being fastened between the partition wall 114 and the stripper section 214 of the apparatus 100 to press the notch 41 into the pouch film 1. Numerous parts of the apparatus 100, particularly the punch pads 213 and 215, are not shown in the diagram in Figure 9.

[0091] The pouch film 1 has an essentially constant and continuous film thickness d1. The notch 41 is pressed into the inner surface 31 of the pouch film 1 with the help of the stripper portion 214, and the partition wall 114 facing the stripper portion 214 accepts the deformation of the outer surface 32 of the pouch film 1. The notch 41 inserted into the pouch film 1 has a notch depth d4. The notch depth d4 is less than the film thickness d1. The film thickness d1 is 183 μm in the embodiment shown in Figure 9. In the illustrated embodiment, the notch depth d4 is about 40% of the film thickness d1. The notch 41 extends in the longitudinal direction Y of the film between a first vertex 46 on the side of the first cup portion 13 on one side and a second vertex 47 on the side of the second cup portion 15 on the other side. The notch width w4 of the notch 41 in the longitudinal direction Y of the film between vertices 46 and 47 is greater than the notch depth d4. The notch width w4 may be as large as the film thickness d1, or smaller than the film thickness d1. In particular, as shown in Figure 9, the notch width w4 may be approximately 75% of the film thickness d1.

[0092] In some embodiments, for example, as implied in Figure 9, the partition wall 114 may have different wall sections in the lateral direction X that have different heights to form a bridge portion 14 having correspondingly offset sections. This will be described in more detail below with reference to Figure 10.

[0093] Figure 10 shows a cross-sectional view through a pouch film where the viewing direction corresponds to the longitudinal direction Y of the film. In the transverse direction X of the film, the bridge section 14 is divided into several sections 42, 43, 44, 45 of different heights above the lower ends of adjacent cup sections 13, 15. The central bridge section 44 is offset from the plane defined by the side sections 16 and / or sealing section 17 surrounding the cup sections 13, 15. Height differences: The offset s can be in the range of 0.05 to 5 mm, particularly in the range of 0.1 mm to 2.5 mm, preferably in the range of 0.2 mm to 2 mm. The central bridge section 44 has a first length L1. The central bridge section 44 may be located between a first lateral bridge section 43 on one side and a second lateral bridge section 45 on the other side. The lateral bridge sections 43, 45 may be at the same height (level) as their respective adjacent side sections 16. In the illustrated example, both lateral bridge sections 43 and 45 have the same second length L2.

[0094] Changes in height or offset s between the lateral bridge sections 43, 45 and the central bridge section 44 are overcome by the respective inclined sections 42 on any one side of the central bridge section 44. The first inclined section 42 connects the first lateral bridge section 43 to the central bridge section 44. The second inclined section 42 connects the second lateral bridge section 45 to the central bridge section 44. The inclined sections 42 have the same third length L3 in the illustrated embodiment. The first length L1 is greater than the third length L3, and preferably at least several times greater than the second length L2. The second length L2 is greater than the third length L3. The sum of the first length L1, the two second lengths L2, and the two third lengths L3 preferably corresponds to the cup width w13 and / or w15. The first length L1 may be dimensioned to be at least half, preferably three-quarters, of the cup width w13 and / or w15. The first length L1 can be dimensioned to be at least 1 / 4, preferably at least 1 / 2, of the overall width of the pouch film 1, particularly in the transverse direction X. The second length L2 may be about 10 mm. The first length L1 may be about 30 mm.

[0095] Figure 11 shows a schematic diagram of the apparatus 100 according to the present disclosure. The apparatus 100 includes, as its components, a die portion 110 (hereinafter referred to as die 110), a punch 210, and a stripper portion 214. The apparatus 100 is configured to allow relative movement of the punch 210 to the die 110 in a downward direction D in order to lower the punch 210 into the die 110. It may be preferable that the punch 210 is fixed and the die 110 is movable in an upward direction opposite to the downward direction D (and rearward). The apparatus 100 is further configured to allow relative movement of the stripper portion 214 to the punch 210 in particular in order to discharge the deep-drawn pouch film 1 from the punch 210.

[0096] In relation to the above description of Figures 1 to 4, the upper die may include or consist of a punch 210, and the lower die may include or consist of a die portion 110.

[0097] The die 110 includes a first containment space 113 and a second containment space 115, and a partition wall 114 separating the containment spaces 113 and 115 from each other. The punch 210 includes a first punch pad 213 and a second punch pad 215. The first punch pad 213 corresponds to the one related to the first containment space 113. The second punch pad 215 corresponds to the one related to the second containment space 115.

[0098] Initially, the flat pouch film 1 is positioned between the punch 210 and the die 110. The lower side surface 32 of the pouch film 1 rests on the upper surface 111 of the die 110. The upper side surface 31 of the pouch film 1 faces the punch 210 and the stripper portion 214.

[0099] To form a pouch film 1 for manufacturing the battery case 11 according to this disclosure, the punch 210 descends into the die 110. More specifically, the first punch pad 213 descends into the first containment space 113 to press the first cup portion 13 into the pouch film 1, and the second punch pad 215 descends into the second containment space 215 to press the second cup portion 15 into the pouch film 1. As the punch 210 descends into the die 110, the bridge portion 14 is formed as an upward projection by a partition wall 114 that protrudes into the space 240 between the punch pads 213 and 215. The wall thickness t of the partition wall 114 corresponds to the width of the space 240.

[0100] As implied in the detailed view of the apparatus 100 shown in Figure 12, the pouch film 1 is pinched between a stripper portion 214 and a partition wall 114. The stripper portion 214 has a projection 241 configured such that a notch 41 is pressed into the inner surface 31 of the pouch film 1. The partition wall has a groove or fold 141 to accommodate the section of the pouch film 1 that is pressed downward when the notch 41 is introduced.

[0101] Figures 13 and 14 show in detail the geometric structure of the partition wall 114 of the die 110, which includes the stripper portion 214 with the protrusion 241 on one side and the groove 141 on the other.

[0102] Figure 13 shows a partition wall 114 fastened to a pouch film 1. The partition wall 114 has a wall thickness t. The partition wall extends longitudinally Y from a first flank 148 to a second flank 149. The peak of the partition wall 114 is continuously curved by two upwardly projecting shoulders 143, 145 surrounding a downwardly projecting central fold 141. The first shoulder 143 forms the edge of the peak toward the first flank 148 which limits the first molding space 113. The second shoulder 145 forms the edge of the peak toward the second flank 149 which limits the second molding space 115. The shoulders 143, 145 are mirror symmetric.

[0103] The shoulders define the first radius of curvature R1. The first radius of curvature R1 of shoulders 143 and 145 is preferably the same. The first radius of curvature R1 of shoulders 143 and 145 may be at least 1 / 10, particularly at least 1 / 6, of the wall thickness t. Alternatively or additionally, the wall thickness t is at least 3 times greater than the first radius of curvature R1, preferably at least 4 times greater. The first radius of curvature R1 may be at least 0.1 mm, preferably at least 0.15 mm, and / or 0.5 mm or less, preferably 0.3 mm or less. In particular, the first radius of curvature R1 may be about 0.2 mm. The first radius of curvature R1 may be at least as much as or even greater than the film thickness d1.

[0104] The groove 141 forms an indentation on the peak of the partition wall 114. The groove 141 has an arched shape that extends from the first shoulder 143 to the second shoulder 145. The groove may define a second radius of curvature R2. The second radius of curvature R2 of the groove may be 1 / 10 or more of the wall thickness t, particularly 1 / 4 or more. Alternatively or additionally, the wall thickness t is at least twice as large as the second radius of curvature R2, preferably at least three times as large as the second radius of curvature R2. The second radius of curvature R2 may be at least 0.2 mm, preferably at least 0.25 mm, and / or 0.8 mm or less, preferably 0.4 mm or less. In particular, the second radius of curvature R2 may be about 0.3 mm. The second radius of curvature R2 is greater than the film thickness d1, but it may be preferable that the second radius of curvature is at least twice as large as the second radius of curvature R2.

[0105] The second radius of curvature R2 is preferably greater than the first radius of curvature R1. The first center distance c12 between the midpoint of the curvature of the shoulders 143 and / or 145 and the midpoint of the curvature of the groove 141 in the downward direction D is at least 0.2 mm, particularly at least 0.3 mm, and / or 0.6 mm or less, particularly 0.5 mm or less. Preferably, c12 is about 0.5 mm.

[0106] Figure 14 shows a stripper portion 214 that fastens to the pouch film 1. The stripper portion 214 generally has a flat plate surface 240. Therefore, the stripper portion 214 may sometimes be referred to as a stripper plate 214. The plate surface 240 extends in the longitudinal direction Y and the transverse direction X. The plate surface 240 has projections 241 that resemble ridges and are configured to bend the pouch film 1 to form a notch 41. The projections 241 curve continuously in the longitudinal direction Y. The projections have a shape similar to a cosine, flattening toward a central tip and either one side. The transition from the flat plate surface 240 to the projections 241 is preferably continuous. Transition sections 243, 245 on either one side of the projection 241 curve continuously until they are at the same level as the plate surface 240. The transition sections 243, 245 are mirror symmetric. The projection 241 has a projection width w14 that extends in the longitudinal direction Y from the start of the first transition section 243 to the end of the second transition section 245. Each transition section 241, 243 starts or ends at the level of the plate surface 240. The projection width w14 may be at least 0.05 mm, preferably at least 0.1 mm, and / or 2 mm or less, preferably 1 mm or less.

[0107] Transition sections 243 and 245 define a third radius of curvature R3. The third radius of curvature R3 in transition sections 243 and 245 is preferably the same. The third radius of curvature R3 may be 1 / 4 or more of the film thickness d1, particularly 1 / 2 or more. Alternatively or additionally, the third radius of curvature R3 may be 10 times or less of the film thickness d1, particularly 6 times or less. The third radius of curvature R3 preferably corresponds to the projection width w14. The third radius of curvature R3 may be at least 0.05 mm, preferably at least 0.1 mm, and / or 2 mm or less, preferably 1 mm or less.

[0108] The protrusion 241 may define a fourth radius of curvature R4. The fourth radius of curvature R4 may be 1 / 10 or more of the film thickness d1, particularly 1 / 4 or more. Alternatively or additionally, the fourth radius of curvature R4 may be 5 times or less of the film thickness d1, particularly 3 times. The fourth radius of curvature R4 preferably corresponds to approximately half of the protrusion width w14. The fourth radius of curvature R4 may be at least 0.02 mm, preferably at least 0.05 mm, and / or 0.75 mm or less, preferably 0.5 mm or less.

[0109] The third radius of curvature R3 is preferably greater than the fourth radius of curvature R4. The second center distance c34 between the midpoint of the curvature of the transition sections 243 and / or 245 and the midpoint of the curvature of the projection 241 in the downward direction D is at least 0.05 mm, particularly at least 0.1 mm, and / or 0.5 mm or less, particularly 0.3 mm or less. Preferably, c34 is about 0.2 mm.

[0110] While preferred embodiments of the Disclosure have been described in detail above, the scope of the Disclosure is not limited thereto, and a variety of modifications and improvements made by those skilled in the art using the basic concepts of the Disclosure as defined in the appended claims also fall within the scope of the Disclosure. [Explanation of Symbols]

[0111] 1: Pouch film 10: Secondary battery 11: Battery case 12: Peripheral area 13: First cup portion 14: Bridge section 15: Second cup portion 16: Side part 17: Sealing section / Degassing section 18: Case Section 1 19: Case Section 2 21: Electrode assembly 22: Electrode Tab 23: Electrode, anode 24: Separator 25: Electrode, Cathode 26: Insulation part 27: Electrode Leads 31: 1st surface (inner surface / inner surface) 32: 2nd surface (outer surface / outer surface) 41: Notch 42: Sloping bridge section 43: First lateral bridge section 44: Central Bridge Section 45: Second lateral bridge section 100: Equipment 110: Die 111:Top surface 114: Partition wall 113, 115: Molding space 141:Wrinkles, grooves 143: First shoulder 145: Second shoulder 210: Punch 213, 215: Punch pad 214: Stripper part 240: Plate surface 241:Protrusion 243: First Transition Section 245: Second Transition Section 300: Equipment 301: Upper die 302: Lower die 303: Upper surface / anvil 304: Die part 305: Base part 306: Protruding section / partition wall 307: Tip portion / peak 308: Gap 309: Punch 310: Stripper part 1000: (Pouch) Film 1001: Secondary battery 1002: Pouch 1003: Peripheral area 1004: Sealing part 1005: Cup / Cup portion 1006: Bridge section 1007: Bad Year 1010: Electrode assembly D: Up / down direction d1: Film thickness d4: Notch depth d13: First cup depth d15: 2nd cup depth H:Hollow space h: height L1: First length L2: Second length L3: Third length l13: First cup length l15: 2nd cup length P: Difference in height R1: 1st radius of curvature R2: Second radius of curvature R3: Third radius of curvature R4: 4th radius of curvature s: offset t: wall thickness w4: Notch width w13: Width of the first cup w14:Protrusion width w15: Width of the second cup X: Horizontal direction Y: Vertical / Long direction

Claims

1. A pouch-type battery case configured to house an electrode assembly having a structure in which electrodes and separators are arranged alternately, The aforementioned pouch-type battery case is A pouch film having a film thickness d1, a first surface and a second surface, A first cup portion formed on the pouch film having a concave shape extending from the first surface to the second surface, A second cup portion formed on the pouch film having a concave shape extending from the first surface to the second surface, and The pouch film between the first cup portion and the second cup portion includes a bridge portion that connects the first cup portion to the second cup portion. The bridge portion includes a notch formed on the first surface that protrudes toward the second surface, A pouch-type battery case wherein the first cup portion is separated from the second cup portion in the longitudinal direction of the pouch film, and the bridge portion extending laterally of the film includes a central bridge section positioned laterally of the film between two lateral bridge sections, the central bridge section being offset from the lateral bridge sections toward the second surface.

2. The pouch-type battery case according to claim 1, wherein the notch has a notch depth d4 that is smaller than the film thickness d1.

3. The pouch-type battery case according to claim 1 or 2, wherein the notch has a notch width that extends in the longitudinal direction of the pouch film between two vertices adjacent to the notch, and the notch width is at least half of the film thickness d1 and / or no more than three times the film thickness d1.

4. The pouch-type battery case according to claim 1, wherein the bridge portion defines the width of the bridge portion that extends from the first cup portion to the second cup portion, and the notch has a notch width w4 that is less than half the width of the bridge portion.

5. The pouch-type battery case according to claim 1, wherein the bridge portion has an M-shaped cross-section in the longitudinal direction of the film.

6. The pouch-type battery case according to claim 1, wherein the pouch film has a film thickness d1 of 100 μm to 250 μm.

7. The pouch-type battery case according to claim 1, wherein the lateral bridge section is at the level of the inner surface of the pouch film surrounding the first cup portion and the second cup portion.

8. The pouch-type battery case according to claim 1 or 7, wherein the central bridge section has a first length, and the lateral bridge sections each have a second length, the first length being greater than the second length.

9. The pouch-type battery case according to claim 1, wherein the bridge portion further includes an inclined section connecting the central bridge section and the lateral bridge section.

10. A secondary battery comprising the battery case described in claim 1, wherein the first cup portion and the second cup portion are folded so as to directly face each other to form a pouch, and the electrode assembly is housed in the pouch.

11. A battery case molding apparatus for manufacturing pouch-type battery cases, wherein the battery case molding apparatus is A die having an upper surface on which a pouch film is placed, and including two molded spaces recessed from the upper surface and a partition wall separating the molded spaces, A punch disposed on the molding space, the punch comprising two punch pads, the punch being operable to lower the punch pads in order to insert the pouch film placed on the upper surface into the molding space, and a stripper portion disposed between the punch pads in cooperation with the punch, The stripper portion includes a protrusion configured to form a notch within the pouch film, A battery case molding apparatus, wherein the partition wall includes wrinkles facing the protrusion in order to accommodate a portion of the pouch film.

12. The battery case molding apparatus according to claim 11, wherein the protrusion has a protrusion height, the protrusion height is less than the film thickness d1 of the molded pouch film and at least 1 / 10 of the film thickness d1, and the wrinkle has a wrinkle depth, the wrinkle depth is less than the film thickness d1 of the molded pouch film and at least 1 / 10 of the film thickness d1.

13. The wrinkle defines a wrinkle width that extends between adjacent shoulders of the partition wall, and the partition wall has a wall thickness t defined between the two molded spaces. The wall thickness t is at least 1.1 times greater than the wrinkle width, and the wall thickness t is 2 times or less of the wrinkle width. The battery case molding apparatus according to claim 12, wherein the wall thickness t is greater than the film thickness d1 of the pouch film to be molded, and the film thickness d1 is 10 times or less the wall thickness t.

14. The aforementioned protrusion has a width between adjacent planar flanks of the stripper portion. The battery case molding apparatus according to claim 12 or 13, wherein the width of the protrusion is greater than the height of the protrusion.

15. A battery case molding apparatus for manufacturing pouch-type battery cases, The aforementioned battery case molding apparatus is A die having an upper surface on which a pouch film is placed, and including two molded spaces recessed from the upper surface and a partition wall separating the molded spaces, A punch disposed on the molding space, the punch comprising two punch pads, the punch being operable to lower the punch pads in order to insert the pouch film placed on the upper surface into the molding space, and a stripper portion disposed between the punch pads in cooperation with the punch, A battery case molding apparatus, wherein the partition wall is positioned laterally between the molding spaces, and the partition wall includes a central wall section positioned laterally between two lateral wall sections, the central wall section being offset relative to the lateral wall sections in the direction in which the punch pad descends.

16. The battery case molding apparatus according to claim 15, wherein the stripper portion and / or the punch has a lug portion, the lug portion is positioned between the punch pads, and the lug portion includes a central lug section positioned laterally between the lateral lug sections, the central lug section protrudes to be introduced into the retracted portion of the die provided by the central wall section.

Images