Pouch-type battery case, secondary battery, and battery forming device

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 forming 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 is very important. Additionally, rechargeable / dischargeable secondary batteries have become an essential power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc. in attempts to solve air pollution caused by existing combustion engine automobiles using fossil fuels and reduce carbon dioxide emissions. Therefore, there is an increasing demand for improving 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 due to various beneficial aspects. For example, they show almost no memory effect compared to nickel-based secondary batteries, and thus can be freely charged and discharged, showing a very low self-discharge rate and a high energy density.

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

[0005] In addition, secondary batteries can be classified based on a structure in which a cathode and an anode are stacked with a separator interposed therebetween. Typically, there can be a stack (laminated) type structure in which a plurality of cathodes and anodes cut into a predetermined unit size are sequentially laminated with a separator interposed between the cathode and the anode or the like. In recent years, in order to solve problems caused by jelly roll type electrode assemblies and stack type electrode assemblies, a stack / folded type electrode assembly has been developed, which is a combination of a jelly roll type electrode assembly and a stack type electrode assembly. Such a stack type electrode assembly can also be referred to as an electrode stack assembly.

[0006] Regarding FIGS. 1 to 4, a method for manufacturing a pouch type secondary battery may include a forming process in which a cup 1005 (or an accommodation space 1005) is formed so that a part of a film (pouch film) 1000 surrounds a concave portion corresponding to the surface area of the electrode assembly 1010. In particular, the forming process may include a step of press-forming the pouch film to form a cup in the film.

[0007] Regarding FIG. 1, a pouch forming device 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 relative to each other (e.g., toward and / or away from each other). Specifically, the lower die 302 may be operable to move toward and then away from the upper die 301. And / or the upper die 301 may be operable to move toward and then away from the lower die 302. Alternatively or additionally, at least one of the upper die 301 and the lower die 302 may not be moved during the formation of the pouch (i.e., during the operation of the device 300).

[0008] The device 300 may include a die portion 304 operably coupled to the lower die 302. Initially, the die portion 304 may be disposed under the lower die 302 and / or at the lower end portion of the lower die 302. For example, the lower die 302 may include sidewalls (not shown in FIG. 1) surrounding the upper surface 303, and the die portion 304 may be at least partially surrounded by the sidewalls of the lower die 302. During operation, the die portion 304 may be at least partially fastened to the sidewalls of the lower die 302. The die portion 304 may include a base portion 305 and a protruding portion 306 extending upward from the base portion 305 (i.e., toward the upper die 301). The protruding portion 306 of the die portion 304 may terminate at the chip portion 307. The protruding portion 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). While the cross-section of the protruding portion 306 may be as shown in FIG. 1, any other suitable shape may be considered as 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 initially supporting a flat pouch film. A part 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 a peak 307 and a part of the protruding portion 306 of the die portion 304 to protrude therethrough. The gap 308 may have the shape of a linear slit in a plan view. The lower die 302 may be shaped so as to provide a hollow space H under the upper surface 303. The die portion 304 may be at least partially disposed inside the hollow space H. For example, the 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, the upward movement of the die portion 304 may be stopped before reaching the lower surface of the anvil 303.

[0010] The device 300 may further include a punch 309 and a stripper portion 310. The punch 309 and / or the stripper portion 310 may be operably coupled to the upper die 301. The punch 309 may have a shape by the cup portion 1005 (see also FIG. 2; also referred to as a cup or a concave cup in the present application) 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 large body portions respectively corresponding to the shape and size of each cup portion formed in the pouch. The bridge portion 1006 remains between the two cup portions 1005. The bridge portion 1006 is formed by the protruding portion 306 of the die portion 304.

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

[0012] During the operation of the device 300 and / or in the corresponding method of forming the pouch, the pouch film (initially flat pouch film) 1000 can be disposed on the upper surface 303 of the lower die 302. The die portion 304 can be moved upward (e.g., raised toward the upper die 301) such that a portion of the chip portion 307 and the protruding portion 306 project upward through the gap 308, thus expanding the corresponding portion of the pouch film 1000. In some examples, the die portion 304 can be moved such that the chip portion 307 abuts (until it abuts) the stripper plate 310. Specifically, the protruding portion 306 can extend between the punches 309 and can fasten the stripper portion 310. Typically, the chip portion 307 of the protruding portion 306 has an essentially semi-circular cross-sectional shape, thus forming a bridge portion 1006 having a corresponding semi-circular chip.

[0013] The punches 309 can be moved downward (e.g., lowered toward the lower die 302) to press the pouch film 1000. Thus, the initially flat pouch film 1000 can be drawn (stretched) according to the shapes of the die chip portion 307, the protruding portion 306, and the punches 309. Specifically, the cup portion can be formed in the pouch according to the shape of the punches 309. The bridge portion can be formed in the pouch between the two cup portions according to the shapes of the protruding portion 306 and the chip portion 307 in combination with the punches 309. The movement of the die portion 304 and the punches 309 can be performed simultaneously or later. Thus, referring to FIGS. 2-4, a pouch 1002 having at least two cup portions 1005 and a bridge portion 1006 therebetween is formed by pressing the initially flat pouch film 1000.

[0014] To release the pouch from the apparatus 300, the punch 309 can be moved upward (i.e., away from the lower die 302), and the die portion can be moved downward (i.e., away from the upper die 301). The stripper portion 310 can be moved to facilitate 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 in particular. For example, the stripper portion 310 can be moved (upward and / or downward) with the punch 309. Alternatively, the stripper portion 310 can be moved upward after a short delay after moving the punch 309 upward. Also, the stripper portion 310 can be moved first downward and then upward.

[0015] The pouch film 1000 can be provided (initially) as a flat sheet. The pouch film 1000 can be plastic press-moldable in the manner described herein. The pouch film 1000 can have, for example, a laminated structure including a metal film and one or more synthetic material layers. For example, the metal film can be made of aluminum (Al), iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), zinc (Zn) or combinations thereof, or an alloy. For example, each of the one synthetic material layer, or synthetic material layers, can be made of, or contain, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene, benzobisoxazole, polyarylate, Teflon® (registered trademark), glass fiber or combinations 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. Accordingly, the protruding portion 306 may hereinafter be referred to as the partition wall 306. Also, the chip portion 307 of the die portion 304 may be configured and specifically formed and shaped to design the upper portion of the bridge portion of the pouch film. The chip portion 307 may hereinafter be referred to as the peak 307. Also, the terms cup, concave cup, and cup portion may be used interchangeably unless otherwise indicated or technically inappropriate.

[0017] Thereafter, 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 laminated on top of each other in an alternating and repeating manner. Subsequently, the film 1000 is folded with respect to the bridge portion 1006 such that the cups 1005 face each other to form the pouch 1002 (FIG. 3). To close the pouch-type secondary battery 1001, the regions of the side portions 1003 of the sheet surrounding the opposing cups 1005 are adhered to each other along the sealing portion 1004 (FIG. 4).

[0018] Ideally, the bridge portion 1006 can fully expand during the folding of the pouch film 1000 such that the resulting pouch 1005 has a substantially flat sidewall where the bridge portion 1006 was (not shown). However, it may occur that the bridge portion 1006 does not fully expand due to the rigidity of the material of the pouch film 1000. Accordingly, a portion of the bridge portion 1006 may remain by folding the pouch film 1000 that protrudes (extends) inward as shown in FIG. 3. Such a remaining portion of the bridge portion 1006 may contact the electrode assembly housed in the pouch 1005 and further deform the electrode assembly. This can cause damage and short circuits to the electrode assembly and, in some cases, result in battery defects, malfunctions, and / or safety issues.

[0019] Furthermore, on one hand, there is a height difference P between the area surrounding the cup 1005 including at least a part of the side portion 1003 that has not undergone the forming and pressing process and includes the sealing portion 1004, and on the other hand, the cup 1005 that has undergone the forming process. Thus, so-called bat-ears 1007 can occur when folding the pouch. Such bat-ears 1007 are part that unnecessarily protrudes or twists outside 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, pose a risk of cracking, and complicate the assembly of the battery module. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0020] An object of the present disclosure is to provide a pouch-type battery case, a secondary battery, and a battery forming device that overcome problems of the prior art and particularly prevent undesirable and potentially harmful deformations of the pouch film.

[0021] However, the problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems and can be variously extended within the scope of the technical idea included in the present disclosure. MEANS FOR SOLVING THE PROBLEMS

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

[0023] Note that some of the features and operations of the system and method for press-forming a pouch as described above with reference to FIGS. 1, 2, and 4 can also be used for the subject matter of the claimed invention and will not be repeated below for the sake of brevity of the description.

[0024] The present disclosure relates to a pouch-type battery case configured to accommodate an electrode assembly having a structure in which electrodes and separators are alternately arranged. Such an electrode assembly may be referred to as an electrode assembly. The pouch-type battery case according to the present 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 lateral 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 particularly serve as an inner surface of the pouch-type battery case and a second surface configured to particularly serve as an outer surface of the pouch-type battery case. The first surface can be fastened to the electrode assembly arranged to be disposed within the pouch-type battery case. The second surface can face away from the electrode assembly and be selectively coupled 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. The pouch film may resemble a web before being formed into a pouch-type battery case, which defines a generally planar extension having a longitudinal direction of the film corresponding to the transfer direction of the pouch film in a forming device, and a 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 from 10 mm to 500 mm, such as from 50 mm to 100 mm, and the extension of the pouch film in the longitudinal direction may be even greater. In the longitudinal direction, the pouch film may be designed to be separated into individual sections to form an extension similar to or "infinite" like a web before being fixed in a pouch-type secondary battery. The film thickness extends perpendicular to both the longitudinal direction and the transverse direction of the film. The film thickness may be at least 100 times smaller, particularly at least 1000 times smaller, than the smaller one of the extensions of the pouch film in the transverse direction or the longitudinal direction of the film.

[0027] The first cup portion is formed in the pouch film having a concave shape from the first surface toward the second surface. The second cup portion is formed in the pouch film having a concave shape 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 device described later, the pouch film may be disposed between the punch and the die so that the downward movement of the punch in relation to the die forms a cup portion that protrudes downward. It will be apparent that the term "downward" as used in the present application is generally understood to refer to a first direction. The first direction is the direction in which the relative movement of the punch takes place in relation to the die for deep drawing the pouch film to form the cup portion, the die may be fixed, the punch may move downward, the punch may be fixed, the die may move upward (in a second direction opposite to 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 arranged in the lateral film direction between the first cup portion and the second cup portion. The bridge portion preferably extends in the lateral direction of the film. The first cup portion and the second cup portion selectively have 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 the second cup depth are preferably greater than the film thickness. The first cup depth and / or the 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 in the lateral direction of the film may be at least 5 times, particularly at least 10 times, preferably at least 20 times greater than the first cup depth and / or the second cup depth. The first cup depth and / or the 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 the electrode assembly that is or will be housed within the battery case. The first portion of the electrode assembly can 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 the electrode assembly that is or will be housed within the battery case. The second portion of the electrode assembly can be at least 1 / 4, at least 1 / 3, or at least 1 / 2 of the electrode stack forming the electrode assembly. The first cup portion and the second cup portion may preferably be arranged symmetrically with respect to each other with the bridge portion therebetween. The length of the bridge portion in the lateral direction of the film (the length of the bridge portion) may preferably correspond to the first cup length and / or the second cup length in the lateral direction of the film. The bridge portion preferably terminates within the first side portion on one lateral side and within the second side portion of the pouch film on the opposite side.

[0029] According to a first aspect of the pouch-type battery case according to the present disclosure, the bridge portion includes a notch formed in 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. In some cases, it may be preferable for the pouch film to continuously curve 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 the first side surface portion of the battery case adjacent to the first cup portion and / or the second cup portion to the second side surface portion of the battery case adjacent to the first cup portion and / or the second cup portion, and the first side surface portion and the second side surface portion are arranged opposite to each other in the lateral direction of the film.

[0030] Advantageously, the notch may serve in a manner similar to a hinge when the first cup portion and the second cup portion are folded together to create a pouch for housing the 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. The provision of 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 the provision of a notch in the bridge portion results in a significant reduction in burr formation. Therefore, it is possible to improve the energy density, improve the dimensional stability of the cell, prevent the risk of cracking, and facilitate the assembly of the battery module.

[0031] In one embodiment of the pouch-type battery case, the notch has a notch depth that is less than the film thickness, particularly less than half of the film thickness. The notch depth can be at least 1 / 10 of the film thickness, preferably at least 1 / 4 of the film thickness. The notch depth can be at least 10 μm, particularly at least 25 μm, preferably at least 50 μm, more preferably at least 100 μm. Alternatively or additionally, the notch depth can be 200 μm or less, particularly 180 μm or less, preferably 150 μm or less. The notch depth is preferably constant 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 in the lateral direction of the film. By providing such a depth to the notch, the pouch-type battery case can have improved folding characteristics while maintaining the structural integrity of the pouch film in the area of the bridge portion. On the other hand, it has been suggested that a notch depth that extends significantly beyond the film thickness can exhibit cracks or other weakening of the pouch film that can result in reduced durability of the battery case.

[0032] In another embodiment of the pouch-type battery case that can be combined with what is described above, the notch has a notch width that extends in the longitudinal direction of the film between two vertices of the pouch film adjacent to the notch. The vertices can be at the peak level of the inner surface of the bridge portion. Alternatively or additionally, the vertices can be at the level of the inner surface surrounding the cup portion, particularly at the level of the plane defined by the side portions.

[0033] The notch width is at least 1 / 2, in particular at least 1 time the film thickness. Alternatively or additionally, the notch width is 3 times or less, in particular 2 times or less the film thickness. The notch depth can be at least 50 μm, in particular at least 100 μm, preferably at least 250 μm. Alternatively or additionally, the notch depth can be 2 mm or less, in particular 1.5 mm or less, preferably 1 mm or less. The notch width is preferably constant at least 30% or at least 50% of the notch length, in particular at least 75% of the length, preferably at least 90% of the length, or at least 95% of the notch length in the lateral direction of the film.

[0034] In an additional embodiment of the pouch-type battery case that can be combined with those described 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 forming (or: drawing) and before folding, the first peripheral portions of the first cup portion and the second cup portion form opposing legs of the bridge portion having opposing outer surfaces facing each other. In particular, the width of the bridge portion is at least 4 times, preferably at least 6 times greater than the film thickness. Alternatively or additionally, the width of the bridge portion can be 20 times or less, in particular 10 times or less 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 apex of the bridge portion adjacent to the notch. The bridge width can be at least 0.5 mm, in particular at least 0.75 mm, preferably at least 1 mm, and / or 5 mm or less, in particular 2 mm or less, preferably 1.5 mm or less. By adapting the bridge width and the notch width to each other as described above, the folding deformation can be controlled so that undesirable wrinkles, the formation of bat ears, or the formation of protrusions that pose a risk of colliding with the electrode assembly housed therein are minimized.

[0035] In one embodiment of the pouch-type battery case that can be combined with those described above, 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 lateral direction of the film. The M-shape of the bridge portion can be sustained 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, in the lateral direction of the film.

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

[0037] The first polymer can be manufactured 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, polyparaphenylene benzobisoxazole, polyarylate, Teflon (registered trademark), and glass fiber. In particular, polyolefin resins such as polypropylene (PP) or polyethylene (PE) can be the main components within the first polymer. Polypropylene (PP) provides excellent mechanical properties including tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance, and excellent chemical properties including corrosion resistance, and thus can be selected as the main component of the sealant layer.

[0038] The second polymer can be manufactured from one or more of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon (registered trademark), and glass fiber. It may be advantageous to mainly use polymers having favorable abrasion resistance and heat resistance such as polyethylene terephthalate (PET).

[0039] The third polymer can be manufactured from one or more of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon (registered trademark), and glass fiber. In particular, nylon resin can be easily adhered to the polyethylene terephthalate (PET) of the surface protection layer and can exhibit an action similar to that of the aluminum alloy of the moisture barrier layer during and after the drawing process. Thus, nylon resin can be used as the main component of the third polymer.

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

[0041] According to a first aspect of the present disclosure, and optionally in combination with at least one or more of its embodiments, according to a second aspect of the present disclosure, the first cup portion is separated from the second cup portion in the longitudinal direction of the film, and the bridge portion extending in the transverse direction of the film includes a central bridge section disposed in the transverse direction of the film between two side bridge sections, and the central bridge section is offset from the side bridge sections towards the second surface. The length of the bridge portion in the transverse direction of the film (the length of the bridge portion) may preferably correspond to the first cup length and / or the second cup length in the transverse direction of 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. The cup portions adjacent to the bridge portion have 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 fastening of the punch into the die. The offset from the side bridge sections to the central bridge section can 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 side bridge sections to the central bridge section can be at least 0.5 times the pouch film thickness, 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 central section and the side sections of the bridge portion, the undesired formation of bat ears can be significantly reduced. It has also been presented that providing a centrally located bridge section offset downward results in a substantial reduction in the collision between the folded bridge portion and the electrode assembly disposed within the battery pouch.

[0042] In one embodiment of the second aspect of the pouch-type battery case, the lateral bridge section is on the same level as the inner surface surrounding the cup portion, in particular on the level of the plane defined by the inner surface surrounding the first cup portion and / or the second cup portion, in particular the side surface portion arranged adjacent to the cup portion in the lateral direction.

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

[0044] According to another embodiment of the second aspect of the pouch-type battery case that can be combined with those described above, the bridge portion further includes an inclined section that connects the central section and the side sections. The first inclined section can be disposed between the first side bridge section and the central bridge section, and the second inclined section can be disposed between the central bridge section and the second side bridge section. The inclined section gradually changes the level of the bridge portion from the central bridge section to the higher level of the side bridge section. The inclined section is particularly continuous, constant, and has a linear inclination. And / or can be formed at least partially or continuously as an arched slope. The lengths of the inclined sections are preferably the same. The length of the inclined section is preferably smaller than the length of the central bridge section. The length of the inclined section (the third length) may be as large as or smaller than the length of the side bridge section. In particular, the third length can 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 an inclination between the side 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, with respect to the control of folding deformation, a significant improvement was perceived when both the first aspect and the second aspect of the present disclosure were implemented as a pouch-type battery case.

[0045] According to a third aspect of the present disclosure, a secondary battery is provided that includes at least one of the first aspect and / or the second aspect of the present disclosure and optionally a battery case according to an embodiment thereof. In the secondary battery, the first cup portion and the second cup portion directly face each other to form a pouch. Further, the electrode assembly is housed within the pouch. Preferably, the secondary battery is formed by folding the pouch film with respect to the notch at the bridge portion. In the secondary battery, side surface portions adjacent to the first cup portion on one hand and the second cup portion on the other hand are fastened to each other, preferably sealed and adhered to each other. Further, sealing portions of the pouch film that are adjacent to the first cup portion or the second cup portion, respectively, and are disposed opposite to the bridge portion with respect to the cup portion are fastened to each other, preferably sealed and adhered to each other. The first peripheral portions of the first cup portion and the second cup portion (opposite to each other before folding of the pouch film with respect to the bridge portion) may form a substantially flat lower end surface of the pouch-type secondary battery.

[0046] The pouch, which is a case of the pouch-type secondary battery, can be manufactured by forming two cup portions by press processing on a flexible pouch film. Then, after the cup portions are formed, the electrode assembly is housed within a housing space of one of the cup portions, and its side surface is sealed. Thereby, the secondary battery is manufactured.

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

[0048] The present disclosure also relates to a battery case forming device for manufacturing a pouch-type battery case, particularly as described above, preferably according to the first aspect of the present disclosure. The battery case forming device includes a die, a punch, and a stripper portion.

[0049] The die has an upper surface on which the pouch film is disposed, and includes two molding spaces sunken from the upper surface 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 disposed above the molding space. The punch includes two punch pads. In particular, 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 disposed on the upper surface into the molding space.

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

[0052] The stripper portion cooperates with the punch and is disposed between the punch pads. Preferably, the stripper portion is disposed opposite the partition wall. The stripper portion is preferably configured to cooperate 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 protrusion configured to form a notch in the pouch film, and the partition wall includes a wrinkle facing the protrusion for accommodating a part of the pouch film, particularly the part of the pouch film displaced by the protrusion. The wrinkle and the protrusion are preferably formed complementarily. The die and the punch are preferably adapted to accommodate the pouch film therebetween when the punch descends into the die. Additionally or alternatively, the protrusion and the wrinkle are adapted to accommodate the pouch film therebetween when the punch descends into the die. When the punch descends into the die, the die and the punch can be adapted to each other to maintain a distance corresponding to the pouch film thickness of the formed pouch film. Alternatively or additionally, when the punch descends into the die, the stripper portion including the protrusion and the die including the wrinkle can be adapted to each other to maintain a distance corresponding to the pouch film thickness of the formed pouch film.

[0054] In an additional development of the battery case forming device according to the third aspect of the present disclosure, the protrusion has a protrusion height, and the protrusion height is smaller than the film thickness of the pouch film to be formed. In particular, the protrusion height is smaller than half of the film thickness or at least 1 / 10 of the film thickness. Alternatively or additionally, the wrinkle has a wrinkle depth, and the wrinkle depth is smaller than the film thickness of the pouch film to be formed. In particular, the wrinkle depth is smaller than half of the film thickness or at least 1 / 10 of the film thickness. The wrinkle depth corresponds to the protrusion height and is preferably the same as it.

[0055] In one embodiment of a battery case forming device that can be combined with a previous one, the wrinkle defines a wrinkle width that extends between adjacent shoulders of the partition wall. The partition wall has a wall thickness defined between two forming spaces. The wall thickness is at least 1.1 times greater than the wrinkle width, particularly at least 1.25 times greater than the wrinkle width. Alternatively or additionally, the wall thickness is not more than 2 times the wrinkle width, particularly not more than 1.5 times the wrinkle width. In particular, the wall thickness is greater than the film thickness of the pouch film to be formed. Preferably, the wall thickness is at least 2 times, preferably at least 4 times greater than the film thickness. Alternatively or additionally, the wall thickness is not more than 10 times the thickness, particularly not more than 6 times the film thickness of the pouch film drawn in the device. The wall thickness can be at least 0.3 mm, particularly at least 0.5 mm, preferably at least 0.75 mm or more, and / or not more than 4 mm, particularly not more than 1.5 mm, preferably not more than 1.25 mm.

[0056] In another embodiment of a battery case forming device that can be combined with a previous one, the protrusion has a protrusion width between adjacent planar flanks of the stripper part. The protrusion width is greater than the protrusion height. In particular, the protrusion width is at least 1.25 times, preferably at least 1.5 times greater than the protrusion height. Alternatively or additionally, the protrusion width is not more than 3 times the protrusion height, preferably not more than 2 times the protrusion height. Preferably, the protrusion has a cosine-shaped cross section.

[0057] The present disclosure also relates to a battery case forming device for manufacturing a pouch-type battery case, particularly as described above, preferably according to the second aspect of the present disclosure. The battery case forming device includes a die, a punch, and a stripper part.

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

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

[0060] The die may preferably be configured to be offset by the punch such that the portion of the pouch film disposed in the region of the protrusion of the forming space forms a cup section. Additionally, the die forms a side portion and / or a sealing portion where the portion of the pouch film disposed on the solid section of the upper surface of the die adjacent to the region of the protrusion of the forming space and the partition wall. And / or may preferably be configured to remain at the first level.

[0061] The stripper portion cooperates with the punch and is disposed between the punch pads. Preferably, the stripper portion is disposed opposite the partition wall. The stripper portion is preferably configured to cooperate with the partition wall to form a bridge portion for the pouch-type battery case within the pouch film.

[0062] According to a third aspect, and according to a fourth aspect of the present disclosure that can be combined with its embodiments, the partition wall is arranged laterally between the forming spaces. The partition wall includes a central wall section arranged laterally between two side wall sections. The central wall section is offset with respect to the side wall sections in the direction in which the punch pad descends. The offset from the side wall section to the central wall section can 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 side wall section to the central wall section can 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 pouch film thickness of the pouch film drawn by the device.

[0063] According to an embodiment of the fourth aspect, the stripper portion and / or the punch has a lug portion. The lug portion is preferably formed complementarily to the partition wall. The lug portion is arranged between the punch pads. The lug portion includes a central lug section arranged laterally between the side lug sections, and the central lug section protrudes to be introduced into the recess of the die provided by the central wall section.

Advantages of the Invention

[0064] According to the embodiment, a more clearly defined pouch-type secondary battery can be formed as compared with the prior art design, and the collision between the electrode assembly and the bridge portion can be avoided, thereby reducing the risk of deforming and / or damaging the anode, cathode and separator. Furthermore, a significant reduction in burr formation can be achieved according to the embodiment. Therefore, it is possible to improve the energy density, improve the dimensional stability of the cell, prevent the risk of cracking, and facilitate the assembly of the battery module.

[0065] The effects of the present disclosure are not limited to the above-described effects, and additional other effects not described above can be clearly understood by those skilled in the art from the description of the appended claims.

Brief Description of the Drawings

[0066]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

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 can easily implement them. The present disclosure can be modified in various different ways and is not limited to the embodiments presented in this application.

[0068] Parts that are not relevant to the description are omitted for clarity in explaining the present disclosure, and like reference numerals designate like elements throughout the description.

[0069] Additionally, in the drawings, the size and thickness of each element are arbitrarily shown for convenience of explanation, and the present disclosure is not necessarily limited to what is shown in the drawings. In the drawings, the thickness of layers, regions, etc. is exaggerated for clarity. In the drawings, for convenience of explanation, the thickness of some layers and regions is exaggerated.

[0070] Additionally, when an element such as a layer, film, region, or plate is referred to as being "on" or "above" another element, it can be understood that it can be directly above any other elements or intervening elements that may also be present. In contrast, when an element is referred to as being "directly above" another element, it means that there are no other intervening elements. Additionally, the words "on" or "above" mean being located on or below the reference part and do not necessarily mean being located on the upper end of the reference part in the opposite direction of gravity. On the other hand, similar to the case where another part is described as being "on" or "above" another part, the case where another part is described as being "below" or "beneath" another part can also be understood with reference to the above content.

[0071] Additionally, throughout the description, when a part is referred to as "including" or "comprising" a particular component, it means that it does not exclude other components and may further include other components unless otherwise specified.

[0072] Additionally, when referring to "plane" through the description, it means when the target portion is visible from the upper side surface, and when referring to "cross-section", it means when the target portion is vertically visible from the side surface of the cross-section cut.

[0073] Hereinafter, the battery case, the pouch-type secondary battery, and the device will be described with reference to the accompanying drawings. The examples shown in FIGS. 1 to 4 and described with reference to them are meant to illustrate general devices and general manufacturing methods, but it should be noted that some of the features and operations of the system and method for press-forming the pouch as described above with reference to FIGS. 1 to 4 can also be embodied in the embodiments as long as they are not technically inappropriate. Such features and operations may not be explicitly repeated below for the sake of brevity of the description.

[0074] The pouch-type battery according to the present disclosure is generally designated by reference numeral 10. The battery case for such a pouch-type battery assembly is generally designated by reference numeral 11. The device for forming the pouch-type battery according to the present disclosure is generally designated by reference numeral 100.

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

[0076] The battery case 11 can be formed, for example, by press-molding the pouch film 1 in a manner similar to the above description with reference to FIGS. 1 to 4. In FIGS. 5 and 6, the battery case 11 includes a first case section 18, a second case section 19, and a bridge portion 14 formed therebetween. 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 rounded 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 rounded corners. The first case section 18 and the second case section 19 are foldable with respect to the bridge portion 14 or can be folded. In particular, one of the first case section 18 and the second case section 19 can be folded over the other case sections 18, 19 such that the first cup portion 13 and the second cup portion 15 are placed on top of each other. A pouch for accommodating the electrode assembly 21 can be obtained in such a manner.

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

[0078] As can be seen from FIG. 5, electrodes 23 and 25 similar to the sheet have electrode tabs 22 protruding from the electrodes 23 and 25 on the opposing side surfaces of the electrode assembly 21 in the lateral direction X. For example, the first electrode tab 22 protrudes from the first side surface of the electrode assembly 21 and can be operatively coupled to the negative electrode 23, and the second electrode tab 22 protrudes on the second side surface of the electrode assembly 21 and is operatively coupled to the positive electrode 25. The first side surface and the second side surface of the electrode assembly 21 may face each other or may refer to the same side surface of the electrode assembly 21 (not shown in the drawings). Each electrode tab 22 has an insulating portion 26 configured to be disposed between the opposing side portions 16 of the battery case 11. The side portions 16 of the battery case 11 are attached to each other through 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 by a respective electrode lead 27 for electrical connection.

[0079] The pouch film 1 can be configured as described above with reference to FIGS. 1 to 4. In particular, the pouch film 1 can include any or all of the features described above with reference to the pouch film 1000 of FIGS. 1 to 4. The pouch film 1 can preferably include a metal layer made of aluminum or an aluminum alloy. Before undergoing the press forming as described herein, the pouch film 1 can be substantially flat. In particular, the pouch film 1 can have a laminated structure including a number of layers laminated together. The pouch film 1 can preferably have a shape similar to a web. Before being processed into the electrode case 11, the pouch film 1 can 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 film width in the lateral direction X (or width direction X) of the film 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 extend considerably more in the web transport direction Y or longitudinal direction Y than the film width, particularly more than several meters. For example, the length of the film in the longitudinal direction Y can 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 made of the pouch film 1 as disclosed in the present application. The battery case 11 includes a first cup portion 13 and a second cup portion 15, which can preferably be manufactured by deep drawing with the apparatus 100 as described herein. The cup portions 13 and 15 are formed adjacent to each other and can be separated by a bridge portion 14 therebetween.

[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 forming) are offset in a direction from the first surface 31 towards the second surface 32, i.e., they are recessed (depressed) in a downward direction D that can be parallel to the direction from the first surface 31 towards the second surface 32. The first surface 31 is disposed above the second surface 32 within the device 100 described hereinafter with respect to FIGS. 11 and 12, and thus may be referred to as the upper film surface 31 and the lower film surface 32.

[0082] While the cup portions 13, 15 are recessed, the bridge portion 14 is maintained at a higher level. The bridge portion 14 may at least partially or completely remain in the plane of the pouch film 1 defined by the side portions 16 surrounding the cup portions 13, 15. In some embodiments, the peak of the bridge portion 14 is disposed entirely in the plane defined by the side portions 16 adjacent to the cup portions 13, 15 in the transverse 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 disposed at the same level as the side portions 16, and at least a portion of which is offset in a (downward) direction from the first surface 31 towards the second surface 32. The offset s of the section is less than the depths d13, d15 of the first cup portion 13 and / or the second cup portion 15, as described hereinafter with reference to FIG. 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 the length in the transverse direction X of the film, as described hereinafter with reference to FIG. 9, for example.

[0084] To form the pouch-type battery 10, the battery case 11 is folded with respect to the bridge portion 14 between the cup portions 13 and 15, as shown in FIG. 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 can provide a film joint at which a well-defined folding motion of the pouch film can be performed.

[0085] As described above, the pouch film 1 can be divided into a first case section 18 (or: first pouch section 18) and a second case section 19 (or: second pouch section 19). The first case section 18 and the second case section 19 can be symmetric to each other with respect to a plane passing through the bridge portion 14. The bridge portion 14 can 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 the present application, the (battery) case sections 18, 19 can also be referred to as pouch sections 18, 19. The first cup portion 13 and the second cup portion 15 can be the same or have substantially the same shape and size. Since the electrode assembly 21 has a shape substantially similar to a regular hexahedron, the accommodation space for the electrode assembly 21 provided by the first cup portion 13 and the second cup portion 15 has a shape corresponding to the straight hexahedron electrode assembly. Therefore, the respective widths w13, w15 of the cup portions 13, 15 in the lateral direction X of the film can preferably have the same size. Also, the respective lengths l13, l15 of the first cup portion 13 and the second cup portion 15 in the longitudinal direction Y of the film can have the same size. The widths w13, w15 of the cup portions 13, 15 extend along the lateral axis of the film between the opposing side surface portions 16 of the case 11, respectively. The respective lengths l13, 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, 15. The peripheral portion 12 can connect the sunken lower ends of the cup portions 13, 15 to the bridge portion 14 and on the other hand, the sealing portions 17 of the respective case sections 18, 19. The peripheral portion 12 can generally be referred to as the side wall of the cup portions 13, 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 can 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 even larger than the second depth d15.

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

[0087] FIG. 7 shows a cross-section passing through the pouch film 1 extending in the longitudinal direction Y of the film. The pouch film 1 is shaped to include a first cup portion 13, a second cup portion 15, and a bridge portion 14 therebetween. In the longitudinal direction Y of the film corresponding to the moving direction of the pouch film 1 via the apparatus 100, both of the cup portions 13, 15 have their respective adjacent degassing portions or sealing portions 17. Thus, each of the cup portions 13 or 15 is disposed 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, the cup portions 13, 15 are both restricted between opposing peripheral portions 12 (which may form the side walls of the respective cup portions 13, 15). The first peripheral portion 12 may form opposing legs of the bridge portion 14. The second peripheral portion 12 may connect the lower ends of the cup portions 13, 15 to the sealing portion 17. The peripheral portion 12 may have an extension corresponding to the depth d13 / d15 of the respective cup portions 13, 15 in the downward direction D. In the transverse direction X of the film corresponding to the viewing direction with respect to the illustration of FIG. 7, the cup portions 13, 15 are restricted by their respective side portions 16. The side portions 16 and the sealing portions 17 of the pouch film 1 can maintain their levels during the shaping (e.g., press forming and / or folding) of the pouch film 1, particularly using the apparatus 100 as will be described later, especially when the cup portions 13 and 15 are recessed from the pouch film 1.

[0088] The chip 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-section. Preferably, the pouch film 1 continuously curves along the path from the first cup portion 13 to the second cup portion 15. Thus, the bridge portion 14 can curve continuously. The bridge portion 14 includes a notch 41 disposed at the center. In the area of the notch 41, the pouch film preferably continuously curves with an arc protruding downward (or: outward). On each side of the notch 41 in the longitudinal direction Y of the film, respective vertices 46, 47, which will be described in more detail below with respect to FIG. 9, can be formed. The vertices 46 and 47 preferably form a continuously curved arc protruding upward (or: inward).

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

[0090] FIG. 9 shows a detailed view of the pouch film 1 fastened between the partition wall 114 and the stripper portion 214 of the apparatus 100 to impress the notch 41 into the pouch film 1. In the view shown in FIG. 9, many parts of the apparatus 100, particularly the punch pads 213, 215, are not shown.

[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 part 214, and the partition wall 114 facing the stripper part 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 FIG. 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 apex 46 on the side surface of the first cup part 13 on one hand and a second apex 47 on the side surface of the second cup part 15 on the other hand. The notch width w4 of the notch 41 in the longitudinal direction Y of the film between the apices 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 FIG. 9, the notch width w4 can be about 75% of the film thickness d1.

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

[0093] FIG. 10 shows a cross-sectional view through a pouch film in which the viewing direction corresponds to the longitudinal direction Y of the film. In the transverse direction X of the film, the bridge portion 14 is divided into several sections 42, 43, 44, 45 of different heights above the lower ends of the adjacent cup portions 13, 15. The central bridge section 44 is offset from the plane defined by the side portion 16 and / or the sealing portion 17 surrounding the cup portions 13, 15. The size of the height difference below: 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 can be arranged 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 can be at the same height (level) as their respective adjacent side portions 16. In the example shown, both of the lateral bridge sections 43, 45 have the same second length L2.

[0094] The change in height or offset s between the side bridge sections 43, 45 and the central bridge section 44 is overcome by respective inclined sections 42 on either side of the central bridge section 44. The first inclined section 42 connects the first side bridge section 43 to the central bridge section 44. The second inclined section 42 connects the second side 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, preferably at least a multiple of 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 widths w13 and / or w15. The first length L1 can be dimensioned to be at least 1 / 2, preferably about 3 / 4 as long as the cup widths w13 and / or w15. The first length L1 can be dimensioned to be at least 1 / 4, preferably at least 1 / 2 as long as the overall width of the pouch film 1 in the transverse direction X. The second length L2 can be about 10 mm. The first length L1 can be about 30 mm.

[0095] FIG. 11 shows a schematic view of an 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 with respect to the die 110 in the downward direction D to lower the punch 210 into the die 110. The punch 210 is preferably fixed, and the die 110 may be movable upward in the 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 with respect to the punch 210, particularly to discharge the pouch film 1 deep-drawn from the punch 210.

[0096] In connection with the above description of FIGS. 1-4, the upper die may include or be constituted by the punch 210, and the lower die may include or be constituted by the die portion 110.

[0097] The die 110 includes a first accommodation space 113, a second accommodation space 115, and a partition wall 114 that separates the accommodation 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 what is related to the first accommodation space 113. The second punch pad 215 corresponds to what is related to the second accommodation space 115.

[0098] The initially flat pouch film 1 is positioned between the punch 210 and the die 110. The lower side surface 32 of the pouch film 1 is placed 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 the pouch film 1 for manufacturing the battery case 11 according to the present disclosure, the punch 210 descends into the die 110. More specifically, the first punch pad 213 descends into the first accommodation space 113 to impress the first cup portion 13 into the pouch film 1, and the second punch pad 215 descends into the second accommodation space 215 to impress the second cup portion 15 into the pouch film 1. When the punch 210 descends into the die 110, the bridge portion 14 is formed as an upward protrusion by the partition wall 114 protruding 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 by the detailed view of the apparatus 100 shown in FIG. 12, the pouch film 1 is pinched between the stripper portion 214 and the partition wall 114. The stripper portion 214 has a protrusion 241 configured such that the notch 41 is pressed into the inner surface 31 of the pouch film 1. The partition wall has a groove or wrinkle 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 structures of the partition wall 114 of the die 110 including the groove 141 on the one hand and the stripper part 214 including the protrusion 241 on the other hand.

[0102] Figure 13 shows the partition wall 114 fastened to the pouch film 1. The partition wall 114 has a wall thickness t. The partition wall extends in the longitudinal direction Y from the first flange 148 to the second flange 149. The peak of the partition wall 114 is continuously curved by two upwardly protruding shoulders 143, 145 surrounding a downwardly protruding central wrinkle 141. The first shoulder 143 forms the edge of the peak towards the first flange 148 that limits the first forming space 113. The second shoulder 145 forms the edge of the peak towards the second flange 149 that limits the second forming space 115. The shoulders 143, 145 are mirror-symmetrical.

[0103] The shoulders define a first radius of curvature R1. The first radius of curvature R1 of the shoulders 143, 145 is preferably the same. The first radius of curvature R1 of the shoulders 143, 145 can be 1 / 10 or more, particularly 1 / 6 or more of the wall thickness t. Alternatively or additionally, the wall thickness t is at least 3 times larger, preferably at least 4 times larger than the first radius of curvature R1. The first radius of curvature R1 can 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 can be about 0.2 mm. The first radius of curvature R1 can be at least as large as or even larger than the film thickness d1.

[0104] The groove 141 forms an indentation at the peak of the partition wall 114. The groove 141 has an arcuate shape extending 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, particularly 1 / 4 or more of the wall thickness t. 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 larger than the film thickness d1, but in some cases it may be preferable that the second radius of curvature is more than twice the second radius of curvature R2.

[0105] The second radius of curvature R2 is preferably larger than the first radius of curvature R1. The first center distance c12 between the midpoint of the curvature of the shoulder 143 and / or 145 in the downward direction D and the midpoint of the curvature of the groove 141 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 is fastened to the pouch film 1. The stripper portion 214 generally has a flat plate surface 240. Thus, the stripper portion 214 can sometimes be referred to as the stripper plate 214. The plate surface 240 extends in the longitudinal direction Y and the transverse direction X. The plate surface 240 has a protrusion 241 similar to a ridge configured to bend the pouch film 1 to form a notch 41. The protrusion 241 continuously curves in the longitudinal direction Y. The protrusion has a shape similar to a cosine that flattens towards the center chip and one of the sides. The transition from the flat plate surface 240 to the protrusion 241 is preferably continuous. The transition sections 243, 245 on either side of the protrusion 241 continuously curve until they reach the same level as the plate surface 240. The transition sections 243, 245 are mirror symmetric. The protrusion 241 has a protrusion 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 of the transition sections 241, 243 starts or ends at the level of the plate surface 240. The protrusion width w14 can be at least 0.05 mm, preferably at least 0.1 mm, and / or 2 mm or less, preferably 1 mm or less.

[0107] The transition sections 243, 245 define a third radius of curvature R3. The third radius of curvature R3 of the transition sections 243, 245 is preferably the same. The third radius of curvature R3 can be at least 1 / 4, particularly at least 1 / 2 of the film thickness d1. Alternatively or additionally, the third radius of curvature R3 can be 10 times or less, particularly 6 times or less of the film thickness d1. The third radius of curvature R3 preferably corresponds to the protrusion width w14. The third radius of curvature R3 can 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, particularly 1 / 4 or more of the film thickness d1. Alternatively or additionally, the fourth radius of curvature R4 may be 5 times or less, particularly 3 times the film thickness d1. 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 larger than the fourth radius of curvature R4. The second center distance c34 between the midpoint of the curvature of the transition section 243 and / or 245 in the downward direction D and the midpoint of the curvature of the protrusion 241 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] Although the preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present disclosure defined in the appended claims are also within the scope of the present disclosure.

Explanation of Signs

[0111] 1: Pouch film 10: Secondary battery 11: Battery case 12: Peripheral part 13: First cup part 14: Bridge part 15: Second cup part 16: Side part 17: Sealing part / Degassing part 18: First case section 19: Second case section 21: Electrode assembly 22: Electrode tab 23: Electrode, anode 24: Separator 25: Electrode, cathode 26: Insulating part 27: Electrode lead 31: First surface (inner surface / internal surface) 32: Second surface (outer surface / external surface) 41: Notch 42: Inclined bridge section 43: First lateral bridge section 44: Central bridge section 45: Second lateral bridge section 100: Device 110: Die 111: Upper surface 114: Partition wall 113, 115: Forming space 141: Wrinkle, groove 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: Device 301: Upper die 302: Lower die 303: Upper surface / anvil 304: Die part 305: Base part 306: Protruding part / partition wall 307: Chip part / peak 308: Gap 309: Punch 310: Stripper part 1000: (Pouch) film 1001: Secondary battery 1002: Pouch 1003: Peripheral part 1004: Sealing part 1005: Cup / cup part 1006: Bridge part 1007: Bat ear 1010: Electrode assembly D: Up / down direction d1: Film thickness d4: Notch depth d13: First cup depth d15: Second cup depth H: Hollow space h: Height L1: First length L2: Second length L3: Third length l13: First cup length l15: Second cup length P: Difference in height R1: First radius of curvature R2: Second radius of curvature R3: Third radius of curvature R4: Fourth radius of curvature s: Offset t: Wall thickness w4: Notch width w13: First cup width w14: Protrusion width w15: Second cup width X: Lateral direction Y: Vertical / longitudinal direction

Claims

1. A pouch-type battery case configured to accommodate an electrode assembly having a structure in which electrodes and separators are alternately arranged, wherein the pouch-type battery case includes a pouch film having a film thickness d1, a first surface, and a second surface, a first cup portion formed in the pouch film having a concave shape extending from the first surface toward the second surface, a second cup portion formed in the pouch film having a concave shape extending from the first surface toward the second surface, and a bridge portion formed in the pouch film between the first cup portion and the second cup portion, connecting the first cup portion to the second cup portion, wherein the bridge portion includes a notch formed in a first surface protruding toward the second surface, the pouch-type battery case.

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, particularly less than half of the film thickness d1.

3. The pouch-type battery case according to claim 1 or 2, wherein the notch has a notch width extending 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, particularly at least 1 time, and / or not more than 3 times the film thickness d1, particularly not more than 2 times the film thickness d1.

4. The pouch-type battery case according to claim 1, wherein the bridge portion defines a width of the bridge portion extending from the first cup portion to the second cup portion, and the notch has a notch width w4 that is smaller than half of 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, particularly 160 μm to 200 μm, preferably 180 μm to 190 μm.

7. A pouch-type battery case according to claim 1, configured to accommodate an electrode assembly having a structure in which electrodes and separators are alternately arranged, wherein the pouch-type battery case includes a pouch film having a film thickness d1, a first surface, and a second surface, a first cup portion formed in the pouch film having a concave shape extending from the first surface toward the second surface, A second cup portion formed in a pouch film having a concave shape facing from the first surface to the second surface, and Including a bridge portion formed in the pouch film between the first cup portion and the second cup portion and connecting the first cup portion to the second cup portion, The first cup portion is separated from the second cup portion in the longitudinal direction of the pouch film, and the bridge portion extending in the transverse direction of the film includes a central bridge section disposed in the transverse direction of the film between two side bridge sections, and the central bridge section is offset from the side bridge section toward the second surface, a pouch-type battery case.

8. The side bridge section is on the level of the inner surface of the pouch film surrounding the first cup portion and the second cup portion, particularly on the level of the plane defined by the inner surface surrounding the first cup portion and / or the second cup portion, The pouch-type battery case according to claim 7.

9. The central bridge section has a first length, the side bridge sections each have a second length, and the first length is greater than the second length, particularly at least twice as large as the second length, The pouch-type battery case according to claim 7 or 8.

10. The bridge portion further includes an inclined section connecting the central bridge section and the side bridge sections, The pouch-type battery case according to claim 7.

11. A secondary battery including the battery case according to 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 accommodated in the pouch, a secondary battery.

12. In particular, a battery case forming device for manufacturing the pouch-type battery case according to claim 1, wherein the battery case forming device includes A die having an upper surface on which a pouch film is disposed, and including two forming spaces recessed from the upper surface and a partition wall separating the forming spaces, A punch disposed on the forming space, the punch including two punch pads, and the punch is operable to lower the punch pads to insert the pouch film disposed on the upper surface into the forming space, and Cooperating with the punch and including a stripper portion disposed between the punch pads, The stripper part includes a protrusion configured to form a notch in the pouch film, The partition wall includes a wrinkle facing the protrusion to accommodate a part of the pouch film, a battery case forming device.

13. The protrusion has a protrusion height, and the protrusion height is smaller than the film thickness d1 of the pouch film to be formed, particularly smaller than half of the film thickness d1, and / or at least 1 / 10 of the film thickness d1, and the wrinkle has a wrinkle depth, and the wrinkle depth is smaller than the film thickness d1 of the pouch film to be formed, particularly smaller than half of the film thickness d1, and / or at least 1 / 10 of the film thickness d1, and particularly the wrinkle depth corresponds to the protrusion height, preferably the same as this, the battery case forming device according to claim 12.

14. The wrinkle defines a wrinkle width extending between adjacent shoulders of the partition wall, and the partition wall has a wall thickness t defined between two of the forming spaces, The wall thickness t is at least 1.1 times larger than the wrinkle width, particularly at least 1.25 times the wrinkle width, and / or the wall thickness t is not more than 2 times the wrinkle width, particularly not more than 1.5 times the wrinkle width, The wall thickness t is larger than the film thickness d1 of the pouch film to be formed, particularly the wall thickness t is at least 2 times, preferably at least 4 times the film thickness d1, and / or the film thickness d1 is not more than 10 times the wall thickness t, particularly not more than 6 times the film thickness d1, the battery case forming device according to claim 13.

15. The protrusion has a protrusion width between adjacent planar flanks of the stripper part, and the protrusion width is larger than the protrusion height, In particular, the protrusion width is at least 1.25 times, preferably at least 1.5 times the protrusion height, and / or the protrusion width is not more than 3 times, preferably not more than 2 times the protrusion height, the battery case forming device according to claim 13 or 14.

16. In particular, for manufacturing the pouch-type battery case according to claim 1, in particular the battery case forming device according to claim 12, The battery case forming device is A die having an upper surface on which a pouch film is disposed, and including two molding spaces recessed from the upper surface and a partition wall separating the molding spaces, A punch disposed on the molding space, the punch including two punch pads, the punch being operable to lower the punch pads for inserting a pouch film disposed on the upper surface into the molding space, and A stripper portion disposed between the punch pads and cooperating with the punch, The partition wall is disposed laterally between the molding spaces, the partition wall includes a central wall section disposed laterally between two side wall sections, and the central wall section is offset with respect to the side wall sections in a direction in which the punch pads are lowered, a battery case forming device. [

17. ] The stripper portion and / or the punch has a lug portion, the lug portion is disposed between the punch pads, the lug portion includes a central lug section disposed laterally between side lug sections, and the central lug section projects to be introduced into a retracted portion of the die provided by the central wall section, the battery case forming device according to claim 16.

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