Pouch-type battery case, secondary battery including same, and method for manufacturing pouch-type battery case

Abstract

A pouch-type battery case according to the present invention is formed as a single body so as to have an accommodation space for accommodating an electrode assembly, and comprises: a pair of main sealing surfaces connected to a main folding edge that defines the lower end of the accommodation space and facing each other to form the accommodation space; and at least one wing part defining a side of the accommodation space and connected to the main folding edge and the pair of main sealing surfaces.

Description

Pouch-type battery case, secondary battery including the same, and method for manufacturing the pouch-type battery case

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0119970, filed September 8, 2023, the entire disclosure of which is incorporated herein by reference.

[0003] [Technical Field]

[0004] The present invention relates to a pouch-type battery case, a secondary battery including the same, and a method for manufacturing the pouch-type battery case. More specifically, the present invention relates to an invention providing an improved pouch-type battery case.

[0005] With the technological development and increasing demand for electric vehicles, mobile devices, and other devices, the demand for secondary batteries as an energy source is increasing. Unlike primary batteries, secondary batteries can be recharged and reused after a single use. A secondary battery consists of an anode and a cathode. When a metal is oxidized at the anode, electricity is generated by the movement of electrons released from the metal. The oxidized metal moves to the cathode through the electrolyte and is reduced.

[0006] To manufacture such a secondary battery, an electrode active material slurry is first applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, which are then laminated on both sides of a separator to form an electrode assembly. The electrode assembly is then housed in a battery case, filled with electrolyte, and sealed.

[0007] Secondary batteries are classified into pouch type and can type, depending on the material of the case that houses the electrode assembly. Pouch type secondary batteries are formed by housing the electrode assembly in a pouch made of a flexible polymer material. Can type secondary batteries are formed by housing the electrode assembly in a case made of a material such as metal or plastic.

[0008] Conventional pouch-type battery cases are manufactured by forming a receptacle by pressing a flexible pouch film. Once the receptacle is formed, an electrode assembly is placed in the receptacle's receptacle space, and the edges of the receptacle are fused to form a sealing portion, thereby sealing the pouch.

[0009] When a receiving portion is formed on each of two pouch films and the pouch films having the receiving portions formed thereon are positioned so as to face each other to form a pouch-shaped battery case, the pouch-shaped battery case can have a plurality of fused sealing portions extending in four directions along the edges. When a single pouch film is folded to form the receiving portion, the folded portion is naturally sealed, so a plurality of fused sealing portions extending in three directions along the edges can be formed.

[0010] The sealing portion formed by fusion may be released due to phenomena such as a temperature rise caused by a secondary battery being shocked or abnormal operation, which generates electrolyte gas. If the sealing portion is released, the electrolyte contained in the receiving space of the pouch-type battery case may leak out of the pouch-type battery case through a crack in the sealing portion where the fusion is released, and the leaked electrolyte may cause electricity to flow to an unwanted part of the secondary battery, thereby damaging the secondary battery. Therefore, it is necessary to minimize electrolyte leakage when the fusion is released at the sealing portion.

[0011] The present invention has been devised to solve the above problems, and the object of the present invention is to provide a novel pouch-type battery case that minimizes electrolyte leakage.

[0012] Another object of the present invention is to provide a pouch-type battery case formed integrally, in which a sealing portion is formed only on one side thereof, so that electrolyte leakage can be minimized when the sealing portion is released from fusion.

[0013] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0014] A pouch-type battery case according to one embodiment of the present invention may be integrally formed to have a receiving space for receiving an electrode assembly. The pouch-type battery case includes a main folding edge defining a lower portion of the receiving space, a pair of main sealing surfaces facing each other to form the receiving space, and at least one wing portion defining sides of the receiving space and connected to the main folding edge and the pair of main sealing surfaces.

[0015] A secondary battery according to one embodiment of the present invention includes a pouch-shaped battery case integrally formed to have an electrode assembly and a receiving space for receiving the electrode assembly, the pouch-shaped battery case including a pair of main sealing surfaces facing the electrode assembly and connected to a main folding edge defining a lower end of the receiving space, at least one wing portion defining a side of the receiving space and connected to the main folding edge and the pair of main sealing surfaces to cover the side of the electrode assembly, and a sealing portion defining an upper end of the receiving space and formed by the pair of main sealing surfaces being adjacent to each other.

[0016] A method for manufacturing a battery case for a pouch according to one embodiment of the present invention includes the steps of preparing a pouch film having a pair of main sealing regions connected to a main folding boundary so that the battery case for a pouch has an accommodation space and a wing region positioned between the pair of main sealing regions, the step of folding the pair of main sealing regions against the main folding boundary so as to form a pair of main sealing surfaces configured to face the accommodation space in a front-rear direction, and the step of forming a wing portion configured to cover a side of the accommodation space by retracting the wing region toward the accommodation space.

[0017] A pouch-type battery case according to one embodiment of the present invention can provide a novel pouch-type battery case that minimizes electrolyte leakage by including a pair of main sealing surfaces facing each other to form a receiving space and a wing portion that connects the pair of main sealing surfaces, which are connected to a main folding edge defining a lower portion of a receiving space.

[0018] According to one embodiment of the present invention, a pouch-type battery case defines a side of a receiving space and includes at least one wing portion connected to a main folding edge and a pair of main sealing surfaces, thereby providing a pouch-type battery case in which a pouch-type battery case formed integrally has a sealing portion formed only on one side, thereby minimizing electrolyte leakage when the sealing portion is released from fusion.

[0019] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0020] FIG. 1 is a perspective view illustrating an electrode assembly according to a first embodiment of the present invention being accommodated in a pouch-type battery case.

[0021] Figure 2 is a conceptual diagram illustrating a case where the electrode assembly illustrated in Figure 1 is accommodated in a pouch-type battery case.

[0022] FIG. 3 is a perspective view illustrating a pouch film for forming the pouch-shaped battery case illustrated in FIG. 1.

[0023] Figure 4 is a perspective view showing the pouch film illustrated in Figure 3 being folded to form a pouch.

[0024] Fig. 5 is a perspective view showing the pouch film illustrated in Fig. 4 folded to completely form a wing portion.

[0025] Figure 6 is a perspective view showing the wing portion of the unfinished pouch illustrated in Figure 5 folded relative to the inner folding edge.

[0026] Figure 7 is a perspective view showing a secondary battery formed by accommodating an electrode assembly after the pouch shown in Figure 6 is cut.

[0027] Fig. 8 is a cross-sectional view showing the secondary battery illustrated in Fig. 7 cut along line Ⅷ-Ⅷ'.

[0028] FIG. 9 is a perspective view illustrating an electrode assembly and a pouch-type battery case according to a second embodiment.

[0029] Fig. 10 is a perspective view illustrating an electrode assembly and a pouch-type battery case according to a third embodiment.

[0030] Fig. 11 is a perspective view illustrating a pouch film for forming a pouch-shaped battery case according to the fourth embodiment.

[0031] Fig. 12 is a perspective view illustrating a pouch film for forming a pouch-shaped battery case according to the fifth embodiment.

[0032] Fig. 13 is a perspective view illustrating a pouch film for forming a pouch-shaped battery case according to the sixth embodiment.

[0033] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0034] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0035] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0036] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to encompass various modifications, equivalents, or alternatives of the embodiments.

[0037] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0038] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0039] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0040] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0041] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0042] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0043] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0044] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0045] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0046] Meanwhile, the terms “upper and lower directions,” “lower side,” and “front and rear directions” used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0047] Specifically, as illustrated in FIG. 1, the direction in which the electrode assembly (10) moves to be accommodated in the accommodation space (100S) is defined as downward, and the upper side, front / rear side, and left / right side can be defined based on this.

[0048] Alternatively, as illustrated in FIG. 3, the direction in which the main sealing area (210) extends with respect to the main folding boundary (210B) may be defined as forward, and the direction in which the wing folding boundary (220B) extends with respect to the main folding boundary (210B) may be defined as left, and the rear, right, and upper and lower sides may be defined based on this.

[0049] The planes, lines, lines, edges, etc. described below can be interpreted as two-dimensional shapes or understood as structures with very small thickness.

[0050] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0051] Example 1

[0052] Fig. 1 is a perspective view illustrating an electrode assembly (10) according to a first embodiment of the present invention being accommodated in a pouch-type battery case (100). Fig. 2 is a conceptual diagram illustrating a case in which the electrode assembly (10) illustrated in Fig. 1 is accommodated in a pouch-type battery case (100).

[0053] Referring to FIGS. 1 and 2, a pouch-type battery case according to a first embodiment and a secondary battery (1) including the same will be described.

[0054] As illustrated in FIG. 1, a secondary battery (1) may include an electrode assembly (10). The electrode assembly (10) may be formed by alternately stacking electrodes (not shown) and separators (not shown). First, a slurry containing an electrode active material, a binder, and a plasticizer may be applied to a positive electrode current collector and a negative electrode current collector to manufacture electrodes such as a positive electrode and a negative electrode. Then, separators may be stacked between the electrodes to form an electrode assembly (10), and the electrode assembly (10) may be inserted into a battery case (not shown) and sealed after applying an electrolyte (50).

[0055] Specifically, the electrode assembly (10) may include two types of electrodes, a positive electrode and a negative electrode, and a separator interposed between the electrodes to mutually insulate the electrodes. This electrode assembly (10) may be provided in a stack type, a jelly roll type, a stack and folding type, etc., depending on the way in which the positive electrode, the negative electrode, and the separator are stacked. The two types of electrodes, i.e., the positive electrode and the negative electrode, may each have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper, respectively. The slurry may typically be formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, etc. in a state in which a solvent is added. The solvent in the slurry may be removed in a subsequent process.

[0056] More specifically, the positive electrode may include a positive electrode material having a strong oxidizing ability that provides electrons. For example, the positive electrode material may include lithium ions, a transition metal, and oxygen. Nickel, cobalt, or manganese may be used as the transition metal. The negative electrode may include a negative electrode material having a strong reducing ability that accepts electrons. For example, the negative electrode material may include graphite. When the secondary battery (1) is charged and discharged, electrons may move according to the movement of lithium ions. In this case, lithium ions may move through an electrolyte (50) located between the positive electrode and the negative electrode, and electrons may move through a conductor connecting the positive electrode and the negative electrode.

[0057] For example, when a secondary battery (1) is being charged, lithium ions in the positive electrode move to the graphite in the negative electrode, receive electrons from the negative electrode, become lithium, and can move between each layer of the graphite. Since graphite has a structure including multiple layers, even if lithium is stored in the graphite, dendrites that form protruding shapes on the negative electrode may not be generated. When the secondary battery (1) is being discharged, lithium between the graphite in the negative electrode releases electrons and becomes lithium ions, which can move to the positive electrode through the electrolyte (50). When the lithium ions move to the positive electrode, they can combine with a transition metal. Since the transition metal can be in an ionic state with multiple charges, even if the transition metal combines with lithium ions and has a different charge than before, the ionic state is maintained, and structural stability can be maintained. However, this is just one example, and the ions that move while repeating charging and discharging may be sodium ions or other substances, not lithium ions. Furthermore, the material used as the negative electrode material may be a material other than graphite. Additionally, the electrolyte (50) may be in a liquid state, but a solid electrolyte (50) may also be used in the secondary battery (1) of the present disclosure.

[0058] The electrode assembly (10) may include electrode tabs (20). The electrode tabs (20) are respectively connected to the positive and negative electrodes of the electrode assembly (10) and may protrude outwardly from the electrode assembly (10) to serve as a path through which electrons may move between the inside and the outside of the electrode assembly (10). The plurality of electrode tabs (20) may protrude in different directions of the electrode assembly (10) as illustrated in FIG. 1, but the present invention is not limited thereto, and the plurality of electrode tabs (20) may protrude in parallel in the same direction or in various directions. However, since the pouch-shaped battery case (100) according to the first embodiment may have the receiving opening (100A) formed only on one side before forming the sealing portion (101), the plurality of electrode tabs (20) according to the first embodiment may be coupled to one side of the electrode assembly (10). However, even so, the extension directions of the plurality of electrode tabs (20) may not necessarily be parallel.

[0059] The electrode assembly (10) may include an electrode lead (30) that is connected to an electrode tab (20) and supplies electricity to the outside of the secondary battery (1). The electrode lead (30) may be connected to the electrode tab (20) by spot welding, etc.

[0060] The electrode assembly (10) may include an insulating portion (40) surrounding a portion of the electrode lead (30). The insulating portion (40) may correspond to a position where the sealing portion (101) is formed. The insulating portion (40) may be positioned between the sealing portions (101) to adhere the electrode lead (30) to the pouch-type battery case (100). In addition, the insulating portion (40) may prevent electricity generated from the electrode assembly (10) from flowing to the pouch-type battery case (100) through the electrode lead (30) and maintain the sealing of the pouch-type battery case (100). Therefore, the insulating portion (40) may be made of a non-conductive material that does not conduct electricity well. For example, the insulating portion (40) may be an insulating tape that is easily attached to the electrode lead (30) and has a relatively thin thickness. However, the present invention is not limited thereto, and various materials may be used as long as the electrode lead (30) can be insulated.

[0061] The electrode tab (20) configured to have a positive electrode may be referred to as a positive electrode tab, the electrode tab (20) configured to have a negative electrode may be referred to as a negative electrode tab, the electrode lead (30) configured to have a positive electrode may be referred to as a positive electrode lead, and the electrode lead (30) configured to have a negative electrode may be referred to as a negative electrode lead. The electrode lead (30) may have one end connected to the electrode tab (20) and the other end protruding outward from the pouch-type battery case (100). That is, the electrode lead (30) may include a positive lead having one end connected to the positive electrode tab and extending in the direction in which the positive electrode tab protrudes, and a negative lead having one end connected to the negative electrode tab and extending in the direction in which the negative electrode tab protrudes. Meanwhile, both the positive electrode lead and the negative electrode lead may have other ends protruding outward from the pouch-type battery case (100). Accordingly, the positive electrode lead and the negative electrode lead may supply electricity generated inside the electrode assembly (10) to the outside. Additionally, the positive and negative tabs can each extend in different directions.

[0062] The positive and negative electrode leads may be made of different materials. The positive electrode lead may be made of the same aluminum material as the positive electrode collector, and the negative electrode lead may be made of the same copper material as the negative electrode collector or a nickel-coated copper material. In addition, a portion of the electrode lead (30) protruding from the outside of the pouch-shaped battery case (100) may serve as a terminal portion and be electrically connected to an external terminal.

[0063] The pouch-type battery case (100) can be manufactured from a highly flexible material to accommodate the electrode assembly (10) therein. The pouch-type battery case (100) can be folded to define a pocket-shaped accommodation space (100S). A accommodation opening (100A) through which the electrode assembly (10) can pass can be defined on one side of the accommodation space (100S). After the electrode assembly (10) is accommodated in the accommodation space (100S) of the pouch-type battery case (100), the accommodation space (100S) can be filled with an electrolyte (50) through the accommodation opening (100A). Thereafter, by forming a sealing portion (101) that seals the accommodation opening (100A) of the pouch-type battery case (100), the electrode assembly (10) and the electrolyte (50) can be prevented from escaping to the outside of the pouch-type battery case (100). A pouch-type battery case (100) can accommodate and seal an electrode assembly (10) such that a portion of the electrode lead (30) is exposed.

[0064] At this time, the "pouch-type battery case (100)" may mean a state in which the receiving opening (100A) is sealed to form a sealing portion (101), or may mean a pouch-type battery case (100) in which the receiving opening (100A) is open. Alternatively, as described below, the "pouch-type battery case (100)" may mean a state in which the pouch film (200) is in the process of being folded. The "pouch-type battery case (100)" may be appropriately understood depending on the context.

[0065] The sealing portion (101) of the pouch-shaped battery case (100) can be formed by heating and pressurizing portions of the facing pouch films (200) to fuse them together. For example, the sealing portion (101) illustrated in FIG. 2 can be formed by moving the upper sides of the first main sealing surface (110') and the second main sealing surface (110'') illustrated in FIG. 1 to come into contact and heating and pressurizing them.

[0066] A pouch film (200) configured to form a first main sealing surface (110') and a second main sealing surface (110'') may include a sealant layer (not shown) made of a polymer, a gas barrier layer (not shown) made of a metal, and a surface protection layer (not shown). The sealant layers included in the first main sealing surface (110') and the second main sealing surface (110'') may be positioned to face each other, and a gas barrier layer may be positioned on the outer side thereof. Since the sealant layers may be made of a polymer, when heat is applied and compressed, the sealant layer of the first main sealing surface (110') and the sealant layer of the second main sealing surface (110'') may melt and be fused to each other. Accordingly, the pouch-type battery case (100) may have a sealing portion (101). Furthermore, a surface protection layer having a polymer material may be positioned on the outside of the gas barrier layer to protect the gas barrier layer.

[0067] The sealant layer may be formed of 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, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, polyolefin resins such as polypropylene or polyethylene may be mainly used. Polypropylene has excellent mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, and heat resistance, and chemical properties such as corrosion resistance, and thus may be mainly used for the sealant layer. Furthermore, it may be formed of non-stretched polypropylene, acid-treated polypropylene, or a polypropylene-butylene-ethylene terpolymer. Here, the acid-treated polypropylene may be maleic anhydride polypropylene (MAH PP). Additionally, the sealant layer may have a single film structure made of one material, or a composite film structure formed by forming layers of two or more materials.

[0068] Furthermore, the gas barrier layer is laminated on the sealant layer to secure the mechanical strength of the pouch-type battery case (100) and block the ingress of gas or moisture from the outside of the secondary battery (1), thereby preventing leakage of the electrolyte (50). The gas barrier layer may be made of a metal, and in particular, the gas barrier layer according to one embodiment of the present invention may be made of a metal including an aluminum alloy of the alloy number AA80XX series. Aluminum can secure a mechanical strength of a predetermined level or higher, while being light in weight and ensuring complementary electrochemical properties and heat dissipation properties by the electrode assembly (10) and the electrolyte (50). The aluminum alloy may include various materials. For example, it may include one or two or more selected from the group consisting of iron, copper, chromium, manganese, nickel, magnesium, and zinc.

[0069] The surface protection layer may be made of 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, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. Preferably, the surface protection layer may have a polyethylene terephthalate (PET) material having insulating properties.

[0070] The pouch-shaped battery case (100) according to the first embodiment may be configured so that the receiving opening (100A) is formed only on one side, and the remaining side covers the receiving space (100S) by folding the pouch film (200). For example, as illustrated in FIG. 1, when the electrode assembly (10) has a rectangular parallelepiped shape, the pouch-shaped battery case (100) may be provided so as to cover the front, rear, left and right sides, and lower sides of the electrode assembly (10). Furthermore, the pouch-shaped battery case (100) may be provided so as to cover the front, rear, left and right sides, and lower sides of the receiving space (100S) by folding the pouch film (200). The upper side of the pouch-shaped battery case (100) may be open to form the receiving opening (100A) that is in communication with the receiving space (100S). After the electrode assembly (10) is accommodated in the accommodation space (100S), as shown in FIG. 2, the upper side of the pouch-shaped battery case (100) can be fused to form a sealing portion (101).

[0071] Since the sealing portion (101) is formed by fusion, the possibility of the sealing being released may be higher than that of the portion formed by folding the pouch-type battery case (100). The sealing portion (101) may be formed by fusion of facing sealant layers made of polymer, but the fusion of the sealant layers may not be completely achieved, and since the sealant layer is brittle due to the nature of the polymer material, there is a high possibility of cracks being formed. On the other hand, since the portion formed by folding the pouch-type battery case (100) is not formed by fusion, it may be free from the possibility of fusion not occurring. Furthermore, even if a crack occurs in the sealant layer in the portion formed by folding, the possibility of the sealing being released may be low because the gas barrier layer made of metal covers the sealant layer. Furthermore, since metal is generally less brittle and more ductile than polymer, a gas barrier layer made of metal may be less likely to crack than a sealant layer made of polymer. On the other hand, as illustrated in FIG. 2, the upper side of the sealing portion (101) is not covered by the gas barrier layer, and the receiving space (100S) is covered only with the sealant layer, so the sealing release may not be prevented by the gas barrier layer. Accordingly, the folded portion of the pouch-type battery case (100) that covers the receiving space (100S) by the sealant layer and the gas barrier layer may be less likely to be sealed than the sealing portion (101) formed by the fusion of the sealant layer.

[0072] As illustrated in FIG. 2, when a sealing crack (102) is formed in the sealing portion (101), the electrolyte (50) located in the receiving space (100S) may leak through the sealing crack (102). When the leaking electrolyte (51) comes into contact with the electrode lead (30), electricity released from the electrode lead (30) may flow to another secondary battery through the leaking electrolyte (51), thereby causing a breakdown of the other secondary battery. Therefore, it is preferable that the sealing portion (101) be formed less. For example, as illustrated in FIG. 2, the sealing portion (101) of the pouch-shaped battery case (100) according to the first embodiment may be formed to correspond to the upper surface of the receiving space (100S). The pouch-shaped battery case (100) may be formed by folding the lower surface, front and rear surfaces, and left and right sides of the receiving space (100S). Accordingly, in the case where the internal pressure of the secondary battery (1) increases due to a problem such as an impact being applied to the secondary battery (1), there may be less concern that a sealing crack (102) will form in the pouch-type battery case (100) other than the sealing portion (101). Furthermore, in the case where the sealing portion (101) is positioned in the opposite direction of the gravity with respect to the pouch-type battery case (100), the possibility of the electrolyte (50) moving through the sealing crack (102) formed in the sealing portion (101) is low, so that leakage of the electrolyte (50) can be further prevented. However, for example, in the case where the sealing portion (101) is formed along the four sides of the pouch-type battery case (100), unlike as illustrated in FIG. 2, more sealing portions (101) are formed, and thus the possibility of sealing cracks (102) forming in the sealing portion (101) increases, which may increase the possibility of electrolyte (50) leakage. Moreover, when the sealing portion (101) is positioned in the direction of gravity with respect to the pouch-type battery case (100), if a crack is formed in the sealing portion (101) positioned in the direction of gravity, the electrolyte (50) can easily move to the outside of the pouch-type battery case (100) through the crack formed in the sealing portion (101).

[0073] Furthermore, since the sealing portion (101) is formed only on one side of the pouch-type battery case (100), the sealing process can be performed with fewer steps. As illustrated in FIG. 2, when the sealing portion (101) is provided only on the upper side of the pouch-type battery case, the heating and pressurizing process can be performed only on the upper side of the pouch-type battery case (100), so the sealing process can be simplified and the number of sealing steps can be reduced compared to when the sealing portion (101) is also formed on the other side of the pouch-type battery case (100). Accordingly, the sealing process time for the pouch-type battery case (100) can be shortened.

[0074] As illustrated in FIG. 1, the pouch-shaped battery case (100) may have a pair of main sealing surfaces (110) forming a receiving space (100S). The pair of main sealing surfaces (110) may cover the front and the rear of the receiving space (100S). The pouch-shaped battery case (100) may include a main folding edge (110E) connecting the pair of main sealing surfaces (110). The main folding edge (110E) may cover the lower side of the receiving space (100S). The pouch-shaped battery case (100) may include a wing portion (120) connecting the pair of main sealing surfaces (110). The wing portion (120) may include a wing folding edge (120E) sealing the side of the receiving space (100S). The wing portion (120) may include an extension portion (140) connected to the main folding edge (110E) and a recessed portion (130) connected to the wing folding edge (120E) between the wing folding edge (120E) and a pair of main sealing surfaces (110). The extension portion (140) and the recessed portion (130) may be formed by folding by an inclined edge (130E) formed therebetween. The pair of main sealing surfaces (110) may include a first main sealing surface (110') and a second main sealing surface (110'') facing each other. The wing portion (120) may include a first wing portion (120') connected to the first main sealing surface (110') and a second wing portion (120'') connected to the second main sealing surface (110''). The first wing portion (120') and the second wing portion (120'') can be connected by a wing folding edge (120E). The first wing portion (120') and the second wing portion (120'') can be folded with respect to the wing folding edge (120E).

[0075] The pouch-type battery case (100) described above will be described in more detail below.

[0076] FIG. 3 is a perspective view illustrating a pouch film (200) for forming a pouch-shaped battery case (100) illustrated in FIG. 1. FIG. 4 is a perspective view illustrating a pouch film (200) illustrated in FIG. 3 being folded to form a pouch. FIG. 5 is a perspective view illustrating a pouch film (200) illustrated in FIG. 4 being folded to completely form a wing portion (120). FIG. 6 is a perspective view illustrating a wing portion (120) of an unfinished pouch illustrated in FIG. 5 being folded relative to an inner folding edge.

[0077] Referring to FIGS. 3 to 6, forming a pouch-type battery case (100) using a pouch film (200) according to the first embodiment is described.

[0078] As illustrated in FIG. 3, a pouch film (200) may be provided. The pouch film (200) may have a predetermined thickness and may be formed integrally. The pouch film (200) may have a flexible material, and thus, the pouch film (200) may be foldable. The different regions and different lines described below may refer to virtual regions and virtual lines. The pouch film (200) may be folded along the virtual lines that separate the virtual regions, thereby forming a pouch-type battery case (100).

[0079] In particular, the dotted line illustrated in FIG. 3 may mean an imaginary line for folding inward. The thick dotted line illustrated in FIG. 3 may mean an imaginary line for folding outward. The thin dotted line illustrated in FIG. 3 may mean an imaginary line to be referred to during the process of folding again with reference to FIG. 5. That is, when the pouch film (200) illustrated in FIG. 3 is folded along the dotted line and the thick dotted line illustrated in FIG. 3, the pouch-type battery case (100) illustrated in FIG. 5 can be formed via the pouch-type battery case (100) illustrated in FIG. 4. Thereafter, the wing portion (120) is folded along the dotted line illustrated in FIG. 5 to form the pouch-type battery case (100) illustrated in FIG. 6, and a portion of the pouch-type battery case (100) illustrated in FIG. 6 can be cut along the cutting surface (150P). This will be described in more detail below.

[0080] As illustrated in FIG. 3, the pouch film (200) may have the shape of a rectangular sheet with four corners cut off. The pouch film (200) may be symmetrical about the center line in the front-back direction and symmetrical about the center line in the left-right direction.

[0081] The pouch film (200) may include a main folding boundary (210B) extending in the left-right direction. For example, as illustrated in FIG. 3, the main folding boundary (210B) may include an area having a roughly rectangular shape. As illustrated in FIG. 4, the main folding boundary (210B) of the pouch film (200) may form a main folding edge (110E) of the pouch-shaped battery case (100) as the pouch film (200) is folded.

[0082] The pouch film (200) may include a pair of main sealing regions (210) extending in opposite directions from the main folding boundary (210B). For example, as illustrated in FIG. 3, a first main sealing region (210') may extend forward from the main folding boundary (210B), and a second main sealing region (210'') may extend rearward from the main folding boundary (210B). The pair of main sealing regions (210) may extend with a width corresponding to the width of the main folding boundary (210B). However, unlike as illustrated in FIG. 3, the pair of main sealing regions (210) may be provided so that their widths change with respect to the extension in the forward / rear direction, such as increasing or decreasing as they extend forward / rear from the main folding boundary (210B).

[0083] As illustrated in FIG. 4, a pair of main sealing areas (210) of the pouch film (200) can be folded with respect to a main folding boundary (210B) to form a pair of main sealing surfaces (110) of the pouch-type battery case (100). More specifically, a first main sealing area (210') of the pouch film (200) can be folded with respect to a boundary line with the main folding boundary (210B) to form a first main sealing surface (110') of the pouch-type battery case (100), and a second main sealing area (210'') of the pouch film (200) can be folded with respect to a boundary line with the main folding boundary (210B) to form a second main sealing surface (110'') of the pouch-type battery case (100). However, as in the fourth embodiment described below with reference to FIG. 11, the main folding boundary (210B) may be provided as a line having no width, and in this case, a pair of main sealing areas (210) of the pouch film (200) may be folded with respect to the main folding boundary (210B), thereby forming a pair of main sealing surfaces (110) of the pouch-type battery case (100). That is, in this case, the main folding boundary (210B) may become a boundary of a pair of main sealing surfaces (110).

[0084] The pouch film (200) may include a wing region (220) extending from the main sealing region (210). The wing region (220) may extend from a pair of the main sealing regions (210) and the main folding boundary (210B). For example, as illustrated in FIG. 3, the wing regions (220) may be provided as a pair extending left and right from the pair of the main sealing regions (210) and the main folding boundary (210B). As illustrated in FIG. 4, the wing region (220) of the pouch film (200) may be folded to form a wing portion (120) of the pouch-shaped battery case (100). The main folding boundary (210B) of the pouch film (200) forms a main folding edge (110E) that covers the lower side of the receiving space (100S) of the pouch-shaped battery case (100), a pair of main sealing areas (210) of the pouch film (200) can form a pair of main sealing surfaces (110) that cover the front and rear sides of the receiving space (100S) of the pouch-shaped battery case (100), and a pair of wing areas (220) of the pouch film (200) can form a pair of wing portions (120) that cover the left and right sides of the receiving space (100S) of the pouch-shaped battery case (100). That is, the pouch film (200) can be folded to cover the lower side, front and rear sides, and left and right sides of the pouch-shaped battery case (100).

[0085] Below, it is described how the wing area (220) of the pouch film (200) is folded to form the wing portion (120) of the pouch-type battery case (100).

[0086] As illustrated in FIG. 3, the wing region (220) may include a first wing region (220'), a second wing region (220''), and / or a wing folding boundary (220B).

[0087] The pouch film (200) may include a wing folding boundary (220B) extending in the longitudinal direction of the main folding boundary (210B) from the main folding boundary (210B). The wing folding boundary (220B) may extend with a width corresponding to the width of the main folding boundary (210B). However, the present invention is not limited thereto, and the wing folding boundary (220B) may extend with a change in width, such as increasing or decreasing in the extension direction.

[0088] The wing folding boundary (220B) may share a virtual line with the main folding boundary (210B). As illustrated in FIG. 4, the wing folding boundary (220B) of the pouch film (200) may be folded based on the virtual line shared with the main folding boundary (210B) of the pouch film (200) to form a wing folding surface that covers the side of the receiving space (100S) of the pouch-type battery case (100). The wing folding boundaries (220B) may be provided in pairs so as to extend left and right from the main folding boundary (210B). For example, a pair of main sealing areas (210) are provided in the front and rear directions with respect to the main folding boundary (210B), and a pair of wing folding boundaries (220B) are provided in the left and right directions with respect to the main folding boundary (210B), so that a shape similar to a development diagram of a rectangular parallelepiped with an open upper side can be provided. The main folding boundary (210B) can define the lower surface of the rectangular parallelepiped, and the pair of main sealing areas (210) and the pair of wing folding boundaries (220B) can each define the side surfaces of the rectangular parallelepiped. In other words, the pair of wing folding boundaries (220B) extending from the main folding boundary (210B) can extend in directions that intersect with the pair of main sealing areas (210). Preferably, a pair of wing folding boundaries (220B) may extend perpendicularly to the extension direction of a pair of main sealing areas (210).

[0089] The pouch film (200) may include a first wing region (220') and a second wing region (220'') connecting a wing folding boundary (220B) and a main sealing region (210). The first wing region (220') may connect the first main sealing region (210') and the wing folding boundary (220B), and the second wing region (220'') may connect the second main sealing region (210'') and the wing folding boundary (220B). The first wing region (220') may share a corner forming an edge of the first main sealing region (210') with the first main sealing region (210'), and may share a corner forming an edge of the wing folding boundary (220B) with the wing folding boundary (220B). The second wing region (220'') may share an edge forming an edge of the second main sealing region (210'') with the second main sealing region (210'') and may share an edge forming an edge of the wing folding boundary (220B) with the wing folding boundary (220B). Since the wing folding boundary (220B) and the pair of main sealing regions (210) may have extension directions that are perpendicular to each other, the edges forming the edges of the wing folding boundary (220B) and the edges forming the edges of the pair of main sealing regions (210) may be perpendicular to each other, and accordingly, the first wing region (220') and the second wing region (220'') may have an "L" shape. The first wing region (220') and the second wing region (220'') of the pouch film (200) can be folded to form the first wing portion (120') and the second wing portion (120'') of the pouch-type battery case (100), as shown in FIG. 4.

[0090] The wing region (220) may include an extension region (240) connected to the main sealing region (210) and a recessed region (230) connected to the wing folding boundary (220B). The extension region (240) may extend leftward and rightward from the main sealing region (210), and the recessed region (230) may extend forward and backward from the wing folding boundary (220B). The extension region (240) and the recessed region (230) may share an inclined line (230L). That is, the extension region (240) and the recessed region (230) may be distinguished by the inclined line (230L). For example, as illustrated in FIG. 3, the extension region (240) and the recessed region (230) may each form an “L”-shaped line.

[0091] The extension region (240) and the recessed region (230) may be configured to be symmetrical with respect to the inclined line (230L). As illustrated in FIG. 4, the extension region (240) of the pouch film (200) may become the extension surface (140) of the pouch-shaped battery case (100), and the recessed region (230) of the pouch film (200) may become the recessed surface (130) of the pouch-shaped battery case (100). Since the extension surface (140) and the recessed surface are configured to face each other, their shapes need to correspond to each other. The inclined line (230L) may extend to be inclined with respect to the longitudinal direction of the main folding boundary (210B). Preferably, the inclined line (230L) may extend at an angle of 45° with respect to the longitudinal direction of the main folding boundary (210B). Since the inclined line (230L) forms a 45° angle with respect to the longitudinal direction of the main folding boundary (210B), the extension surface (140) and the recessed surface (130) may be arranged to be symmetrical with respect to the inclined line (230L). However, the present disclosure is not limited thereto, and even if the inclined line (230L) does not form a 45° angle with respect to the longitudinal direction of the main folding boundary (210B), the extension region (240) and the recessed region (230) can be folded with respect to the inclined line (230L) to cover the side of the receiving space (100S) of the pouch-type battery case (100). Therefore, the present disclosure may also include a case where the inclined line (230L) does not form a 45° angle with respect to the longitudinal direction of the main folding boundary (210B).

[0092] More specifically, the first wing portion (120') may include a first extension portion (240') extending from the first main sealing portion (210') to a first slant line (230L') and a first recessed portion (230') extending from the wing folding boundary (220B) to the first slant line (230L'). The second wing portion (120'') may include a second extension portion (240'') extending from the second main sealing portion (210'') to a second slant line (230L'') and a second recessed portion (230'') extending from the wing folding boundary (220B) to the second slant line (230L''). The first recessed area (230') can be connected to the second recessed area (230'') by the wing folding boundary (220B). As illustrated in FIG. 4, the first recessed area (230') and the second recessed area (230'') can be folded at the boundary line of the wing folding boundary (220B) to form the first recessed surface (130') and the second recessed surface (130'') of the pouch-type battery case (100).

[0093] However, as illustrated in FIG. 6, in the pouch-shaped battery case (100) according to the first embodiment, the extension surface (140) and the recessed surface (130) may be cut to have different shapes from the extension surface (140) and the recessed surface (130) illustrated in FIG. 5. In the present disclosure, the extension surface (140) and the recessed surface (130) before cutting and the extension surface (140) and the recessed surface (130) after cutting are described as the extension surface (140) and the recessed surface (130), respectively, without distinction of terms. In each description, the extension surface (140) and the recessed surface (130) may have different meanings depending on the context.

[0094] The pouch film (200) may include a side folding line (240L) that divides the main sealing region (210) and the extension region (240). As illustrated in FIG. 5, the side folding line (240L) may be a reference line along which the first wing portion (120') and the second wing portion (120'') of the pouch-type battery case (100) are folded. The side folding line (240L) may extend from the boundary line of the main folding boundary (210B) and the wing folding boundary (220B) in the extension direction of the boundary line of the main folding boundary (210B) and the wing folding boundary (220B). In other words, the side folding line (240L) included in the pouch film (200) may be positioned on a straight line formed by extending the boundary line of the main folding boundary (210B) and the wing folding boundary (220B). The end of the side folding line (240L) may be positioned at the point where the inclined line (230L) and the main folding boundary (210B) meet. As illustrated in FIG. 5, the first wing portion (120') and the second wing portion (120'') are formed by extending upward from a point where the inclined edge (130E) and the main folding edge (110E) meet, so the side folding edge (140E) capable of folding the first wing portion (120') and the second wing portion (120'') can be formed from a point where the inclined line (230L) forming the inclined edge (130E) and the main folding boundary (210B) forming the main folding edge (110E) meet. The side folding line (240L) may include a first side folding line (240L') forming an edge of the first wing region (220') and a second side folding line (240L) forming an edge of the second wing region (220').

[0095] The pouch film (200) illustrated in FIG. 3 may be folded based on the previously described virtual line to become the pouch-shaped battery case (100) illustrated in FIG. 4. At this time, a pair of main sealing regions (210) and a pair of wing folding boundaries (220B) may be folded toward the receiving space (100S) based on the main folding boundary (210B), and the first wing region (220') and the second wing region (220'') may be folded so that the inclined line (230L) is recessed toward the receiving space (100S). At this time, the recessed region (230) may be folded in a direction away from the receiving space (100S) with respect to the wing folding boundary (220B). The first concave region (230') and the second concave region can form a first concave surface (130') and a second concave surface (130''), and the first concave surface (130') and the second concave surface (130'') can form a concave concave recess (130S) toward the receiving space (100S) together with the wing folding edge (120E). The pouch film (200) illustrated in FIG. 3 can form a pouch-shaped battery case (100) illustrated in FIG. 4, while forming an receiving space (100S) in which an electrode receptor (see FIG. 1) can be received, and an receiving opening (100A) defining one side of the receiving space (100S).

[0096] The pouch-shaped battery case (100) illustrated in FIG. 4 can become the pouch-shaped battery case (100) illustrated in FIG. 5 by moving each side in the direction of the arrow illustrated.

[0097] As illustrated in FIG. 5, the pouch-shaped battery case (100) may include a first wing portion (120') and a second wing portion (120'') extending outwardly of the receiving space (100S). The first wing portion (120') and the second wing portion (120'') may be folded based on the first side folding edge (140E') and the second side folding edge (140E''). The secondary batteries (1) need to be loaded in multiples to generate strong power, and the volume occupied by each secondary battery (1) during the loading process of the secondary batteries (1) should be small so that a large number of secondary batteries (1) can be loaded per unit volume. Therefore, it may be desirable for the pouch-shaped battery case (100) forming at least a part of the exterior of the secondary battery (1) to have a small volume. The pouch-type battery case (100) can reduce the volume it occupies when loaded by folding the first wing portion (120') and the second wing portion (120'').

[0098] For example, as illustrated in FIG. 5, a pair of first wing parts (120') positioned on the left and right sides of the first main sealing surface (110') can be folded in a direction toward each other. The pair of first wing parts (120') can be folded by rotating about the first side folding edge (140E'), respectively. A pair of second wing parts (120') positioned on the left and right sides of the second main sealing surface (110'') can also be folded to correspond to the movement of the first wing part (120').

[0099] The pouch-shaped battery case (100) illustrated in FIG. 5 can become the pouch-shaped battery case (100) illustrated in FIG. 6 when the first wing part (120') and the second wing part (120'') move in the direction of the arrow.

[0100] As illustrated in FIG. 6, the pouch-shaped battery case (100) may have an approximately rectangular parallelepiped shape. In particular, the receiving space (100S) may have a rectangular parallelepiped shape. Assuming a virtual cutting surface (150P) connecting the end of the first inclined edge (130E') and the end of the second inclined edge (130E'') of the pouch-shaped battery case (100), the pouch-shaped battery case (100) may be cut along the cutting surface (150P). Accordingly, a portion of the first wing portion (120'), the second wing portion (120''), and / or the wing folding edge (120E) may be cut and removed. In other words, the length of the first wing portion (120'), the second wing portion (120''), and / or the wing folding edge (120E) may be shortened. Since the extension surface (140) and the recessed surface (130) are connected by the inclined edge (130E), the extension surface (140) and the recessed surface (130) can be connected as much as the inclined edge (130E) extends. The inclined edge (130E) extends from the lower side to the upper side of the extension surface (140) and the recessed surface (130), and the ends of the extension surface (140) and the recessed surface (130) that are not connected by the inclined edge (130E) may not be connected. That is, a gap may be formed between the extension surface (140) and the recessed surface (130) in a portion of the upper side of the extension surface (140) and the recessed surface (130). When the electrolyte (50) is accommodated in the receiving space (100S) of the pouch-type battery case (100) before cutting, the electrolyte (50) may leak out through a gap formed in a portion of the upper side of the extension surface (140) and the insertion surface (130). To prevent this, a portion where the extension surface (140) and the insertion surface (130) are not connected may be cut. That is, after cutting, the extension surface (140) and the insertion surface (130) may be configured to cover the side of the receiving space (100S) by the length that the inclined edge (130E) extends.

[0101] As illustrated in FIG. 6, the pouch-type battery case (100) may have its cutting area (150) removed based on the cutting surface (150P). More specifically, before the cutting area (150) is removed, the electrode assembly (10) may be placed in the receiving space (100S) of the pouch-type battery case (100), the upper side of the cutting area (150) may be sealed first, and then an activation process may be performed to test charge and discharge the electrode assembly (10). The secondary battery (1) that has undergone the activation process may generate gas, and in order to remove the generated gas, a hole may be formed in the cutting area (150) to release the gas, and the lower side of the cutting area (150) may be sealed to form a sealing portion (101). Thereafter, the cutting area (150) may be removed. However, the present invention is not limited thereto, and for a pouch-type battery case (100) that is cut based on a cutting surface (150P) and from which the cut cutting area (150) is removed, an electrode assembly (10) that is provided to correspond to the receiving space (100S) can be accommodated in the receiving space (100S). After the electrode assembly (10) is accommodated in the receiving space (100S), the pouch-type battery case (100) can be sealed by fusing the first main sealing surface (110') and the second main sealing surface (110'') through the receiving opening (100A) formed on the upper side. More specifically, after the electrode assembly (10) is accommodated in the receiving space (100S) and the electrolyte (50) is injected into the receiving space (100S), the receiving opening (100A) of the pouch-type battery case (100) can be sealed.

[0102] The pouch-type battery case (100) before forming the sealing portion (101) is described again as follows.

[0103] As illustrated in FIG. 3, a method for manufacturing a pouch-type battery case (100) may include a step of preparing a pouch film (200) having a pair of main sealing areas (210) connected to a main folding boundary (210B) so that the pouch-type battery case has a receiving space (100S) and a wing area (220) positioned between the pair of main sealing areas (210).

[0104] A method for manufacturing a pouch-type battery case (100) may include a step of folding a pair of main sealing areas (210) against a main folding boundary (210B) to form a pair of main sealing surfaces (110) configured to face the receiving space (100S) in the front-back direction.

[0105] A method for manufacturing a pouch-type battery case (100) may include a step of forming a wing portion (120) configured to cover a side of a receiving space (100S) by retracting a wing region (220) toward the receiving space (100S).

[0106] As illustrated in FIG. 6, a pouch-type battery case (100) formed by a method for manufacturing a pouch-type battery case (100) may be integrally formed to have a receiving space (100S) for receiving an electrode assembly (10). In particular, a pair of main sealing surfaces (110) may be connected to a main folding edge (110E) defining a bottom of the receiving space (100S) and may face each other to form the receiving space (100S). At least one wing portion (120) may define a side of the receiving space (100S) and may be connected to the main folding edge (110E) and the pair of main sealing surfaces (110).

[0107] At least one wing portion (120) may include a first wing portion (120') extending from one main sealing surface (110), a second wing portion (120'') extending from the other main sealing surface (110), and a wing folding edge (120E) connecting the first wing portion (120') and the second wing portion (120''). At the edge of the wing folding edge (120E), the first wing portion (120') and the second wing portion (120'') may extend parallel to each other.

[0108] The wing folding edge (120E) may extend perpendicularly to the extension direction of the main folding edge (110E). Since the wing folding edge (120E) may form a side surface of the receiving space (100S), and the main folding edge (110E) may form a lower surface of the receiving space (100S), the fact that the wing folding edge (120E) is perpendicular to the main folding edge (110E) may mean that the lower surface and the side surface of the receiving space (100S) are perpendicular to each other. Through this, the lower surface and the side surface of the electrode assembly (10) corresponding to the receiving space (100S) may be perpendicular to each other. Furthermore, the lower surface and the side surface of the secondary battery (1) may be perpendicular to each other. The fact that the secondary battery (1) has two perpendicular surfaces may mean that when a plurality of secondary batteries (1) are stacked, the number of secondary batteries (1) stacked per unit space may increase.

[0109] The first wing portion (120') and the second wing portion (120'') may include an extension surface (140) extending from a pair of main sealing surfaces (110), a recessed surface (130) extending from a wing folding edge (120E) toward the extension surface (140), and an inclined edge (130E) connecting the extension surface (140) and the recessed surface (130). The wing folding edge (120E) may connect the recessed surface (130) of the first wing portion (120') and the recessed surface (130) of the second wing portion (120'). This may be a shape that appears in the pouch-type battery case (100) by folding the pouch film (200) to form the pouch-type battery case (100).

[0110] In particular, the extension surface (140) may be positioned between a pair of main sealing surfaces (110) and the recessed surface (130) so as to face the pair of main sealing surfaces (110). In the case of embodiments other than the first embodiment described below, the wing portion (120) of the first embodiment may have a different shape depending on the manner in which the first wing portion (120') and the second wing portion (120'') are folded. The wing portion (120) of the first embodiment is characterized in that the extension surface (140) may be positioned between one of the pair of main sealing surfaces (110) and the recessed surface (130) so as to face one of the pair of main sealing surfaces (110). This may be to reduce the volume occupied by the secondary battery (1) mentioned above.

[0111] The slant edge (130E) can meet the main folding edge (110E) and the wing folding edge (120E) at one point. More specifically, the lower end of the slant edge (130E) can meet the main folding edge (110E) and the wing folding edge (120E) at one point. As described above, the lower end of the slant edge (130E) may be a portion from which the side folding edge (140E) extends, and therefore, the point from which the extension of the side folding edge (140E) begins may be located on the boundary line between the wing folding edge (120E) and the main folding edge (110E).

[0112] In particular, the inclined edge (130E) can be extended at an angle of 45 degrees to the extension direction of the main folding edge (110E). This is because, as mentioned above, the inclined edge (130E) forms a boundary between the extension surface (140) and the recessed surface (130), and the extension surface (140) and the recessed surface (130) are adjacent to each other so as to face each other, thereby forming the first wing portion (120') and the second wing portion (120''). Therefore, it is preferable that the extension surface (140) and the recessed surface (130) have corresponding shapes. In other words, the extension surface (140) and the recessed surface (130) can have shapes that are symmetrical with respect to the inclined edge (130E), or in other words, the extension surface (140) and the recessed surface (130) can have the same overlapping area.

[0113] Furthermore, the pouch-type battery case (100) according to the first embodiment may have a main folding edge (110E) having a width corresponding to the width of the electrode assembly (10).

[0114] Below, additional explanations will be given regarding the pouch-type battery case (100) formed up to the sealing portion (101).

[0115] Fig. 7 is a perspective view showing a secondary battery (1) formed by accommodating an electrode assembly (10) after the pouch shown in Fig. 6 is cut. Fig. 8 is a cross-sectional view showing the secondary battery (1) shown in Fig. 7 cut along line Ⅷ-Ⅷ'.

[0116] As illustrated in FIG. 7, a sealing portion (101) may be formed on the upper side of the pouch-type battery case (100). That is, the sealing portion (101) may define the upper end of the receiving space (100S) and may be formed by a pair of main sealing surfaces (110) being adjacent to each other. The upper side of the receiving space (100S) may be covered by the sealing portion (101), the side of the receiving space (100S) may be covered by the pair of main sealing surfaces (110) and the wing portion (120), and the lower side of the receiving space (100S) may be covered by the main folding edge (110E), so that the receiving space (100S) may be surrounded by the pouch-type battery case (100). Accordingly, the receiving space (100S) may be sealed to the outside of the pouch-type battery case (100) by the pouch-type battery case (100). The electrolyte (50) positioned within the receiving space (100S) can be prevented from leaking to the outside of the pouch-type battery case (100).

[0117] In particular, while forming the sealing portion (101), a portion of the upper portion of the wing portion (120) may melt and then solidify again. As illustrated in FIG. 8, a pair of main sealing surfaces (110) and the first wing portion (120'), the second wing portion (120''), and the wing folding edge (120E) may be adjacent to each other. In particular, the upper portions of the first wing portion (120'), the second wing portion (120'') and the wing folding edge (120E) can be positioned adjacent to the upper portions of a pair of main sealing surfaces (110), and when the upper portions of the first wing portion (120'), the second wing portion (120'') and the wing folding edge (120E) melt and then solidify again, they solidify into a shape as shown in FIG. 8, so that a spring back phenomenon in which the first wing portion (120') and the second wing portion (120'') move away from the first main sealing surface (110') and the second main sealing surface (110'') can be prevented.

[0118] Hereinafter, embodiments different from the first embodiment will be described. Commonalities with the first embodiment will be omitted as much as possible, and other embodiments will be described focusing on differences. In other words, it is self-evident that any details not described in the second through sixth embodiments, if necessary, can be supplemented through the contents of the first embodiment. Furthermore, if the configurations illustrated in FIGS. 1 through 8, which were referenced while describing the first embodiment, can also be applied to the second through sixth embodiments, the same drawing numbers may be assigned thereto, and the descriptions may be omitted.

[0119] Second Example

[0120] FIG. 9 is a perspective view illustrating an electrode assembly (10-1) and a pouch-type battery case (100) according to a second embodiment.

[0121] Referring to FIG. 9, an electrode assembly (10-1) and a pouch-type battery case (100-1) according to a second embodiment are described.

[0122] The pouch-type battery case (100-1) according to the second embodiment is different from the pouch-type battery case (100) according to the first embodiment in that the first wing portion (120'-1) and the second wing portion (120''-1) are not folded relative to the first main sealing surface (110') and the second main sealing surface (110''). In other words, the pouch-type battery case (100) according to the second embodiment is different in that the first wing portion (120') and the second wing portion (120'') are not folded relative to the first side folding edge (140E') and the second side folding edge (140E'') during the folding process of the pouch-type battery case (100) referring to FIG. 5. That is, the extension surface (140) of the second embodiment can be extended in the extension direction of the pair of main sealing surfaces (110).

[0123] Furthermore, the electrode assembly (10-1) according to the second embodiment may have a trapezoidal cross-section, unlike the electrode assembly (10) according to the first embodiment, which has a rectangular shape. Accordingly, when a pouch-type battery case (100) is formed using a pouch film (200) of the same size, the electrode assembly (10-1) according to the second embodiment may be larger than the electrode assembly (10) according to the first embodiment. Since the larger electrode assembly (10-1) may include more positive electrode materials and more negative electrode materials, the electric capacity of the secondary battery (1-1) may increase. Furthermore, since the shape of the secondary battery (1-1) may have a shape of a column whose cross-section is approximately trapezoidal, the shape of the battery module formed by stacking the secondary batteries (1-1) may also be formed to correspond thereto. Therefore, the secondary battery (1-1) according to the second embodiment may provide a different shape from the secondary battery (1-1) according to the first embodiment, thereby allowing the battery module to have various shapes. In other words, the electrode assembly (10) may have an inclined surface corresponding to the inclined edge (130E).

[0124] The inclined edge (130E) may extend in a direction that moves away from the main folding edge (110E) as it goes upward. That is, the inclined edge (130E) may extend in a direction different from the direction in which the main folding edge (110E) extends. The inclined edge (130E) is a boundary between the extension surface (140) and the indentation surface (130) that form the first wing portion (120') and the second wing portion (120''), and is a portion formed by indenting a portion of the wing area (220) of the pouch film (200) toward the receiving space (100S), so the inclined edge (130E) may extend upward and extend toward the outside of the receiving space (100S).

[0125] The pouch-type battery case (100) according to the second embodiment can provide an opening in which the electrode assembly (10) is accommodated in the accommodation space (100S) by spacing the main sealing surface (110) apart from the first wing portion (120') or the second wing portion (120'').

[0126] The pouch-shaped battery case (100) according to the second embodiment may be provided such that the main folding edge (110E) is formed in a line shape, similar to the pouch-shaped battery case (100) according to the third embodiment described below. This is because the main folding edge (110E) in the second embodiment does not need to correspond to the width of the electrode assembly (10).

[0127] Third Example

[0128] FIG. 10 is a perspective view illustrating an electrode assembly (10-2) and a pouch-type battery case (100-2) according to a third embodiment.

[0129] Referring to FIG. 10, an electrode assembly (10-2) and a pouch-type battery case (100-2) according to a third embodiment are described.

[0130] The pouch-type battery case (100-2) according to the third embodiment can be viewed as an intermediate form between the pouch-type battery case (100-2) according to the first embodiment and the pouch-type battery case (100-2) according to the second embodiment. In other words, the pouch-type battery case (100) according to the first embodiment is an embodiment in which the entirety of the first wing portion (120') and the second wing portion (120'') is folded against a pair of main sealing surfaces (110), and the pouch-type battery case (100-1) according to the second embodiment is an embodiment in which the entirety of the first wing portion (120'-1) and the second wing portion (120''-1) is not folded against a pair of main sealing surfaces (110), while the pouch-type battery case (100-2) according to the third embodiment may be an embodiment in which a portion of the first wing portion (120'-2) and the second wing portion (120''-2) is folded against a pair of main sealing surfaces (110).

[0131] A pouch-shaped battery case (100-2) according to a third embodiment may include an extension surface (140) including a first extension surface segment (141a) extending from a pair of main sealing surfaces (110) and positioned on a plane along which the pair of main sealing surfaces (110) extend, and a second extension surface segment (141b) folded from the first extension surface segment (141a) to cover the first extension surface segment (141a) from the outside.

[0132] Furthermore, the electrode assembly (10-2) according to the third embodiment may have a pentagonal cross-section, unlike the electrode assembly (10-2) according to the first embodiment, which has a rectangular shape. Accordingly, when a pouch-type battery case (100-2) is formed using a pouch film (200) of the same size, the electrode assembly (10-2) according to the third embodiment may be larger than the electrode assembly (10) according to the first embodiment. Since the effect thereof is the same as that described in the second embodiment, its description is omitted.

[0133] Example 4

[0134] Fig. 11 is a perspective view illustrating a pouch film (200) for forming a pouch-type battery case (100) according to the fourth embodiment.

[0135] Referring to FIG. 11, a pouch-type battery case (100) according to the fourth embodiment is described.

[0136] The pouch-shaped battery case (100) (not shown) according to the fourth embodiment differs from the pouch-shaped battery case (100) according to the first embodiment in that the main folding edge (110E) (not shown) does not have a width. The main folding edge (110E) of the pouch-shaped battery case (100) according to the first embodiment could be formed to correspond to the width of the electrode assembly (10). However, even if the main folding edge (110E) of the pouch-shaped battery case (100) does not have a width corresponding to the width of the electrode assembly (10), the electrode assembly (10) can be accommodated in the pouch-shaped battery case (100). When the electrode assembly (10) is inserted into the gap between the first main sealing surface (110') and the second main sealing surface (110'') of the pouch-shaped battery case (100) of the fourth embodiment, the electrode assembly (10) can be accommodated inside the pouch-shaped battery case (100). In this case, the wing folding edge (120E) (not shown) of the pouch-shaped battery case (100) may also have no width.

[0137] The pouch-shaped battery case (100) according to the fourth embodiment may, for example, resemble the shape of a candy bag. The candy bag can accommodate an object in a thick space formed within it based on the corners formed on the upper, lower, left, and right sides.

[0138] To this end, the pouch film (200-3) forming the pouch-shaped battery case (100) may have a main folding boundary (210B-3) having no width. Furthermore, the pouch film (200-3) may include a wing folding boundary (220B-3) having no width, similar to the main folding boundary (210B-3).

[0139] However, as explained above, since the absence of width cannot exist in reality, it will be understood as having a very small width.

[0140] Example 5

[0141] FIG. 12 is a perspective view illustrating a pouch film (200) for forming a pouch-type battery case (100) according to the fifth embodiment.

[0142] Referring to FIG. 12, a pouch-type battery case (100) according to the fifth embodiment is described.

[0143] The pouch-type battery case (100) (not shown) according to the fifth embodiment may be the same as the pouch-type battery case (100) according to the first embodiment. However, there may be a difference in the pouch film (200-4) for making the pouch-type battery case (100) according to the fifth embodiment. The pouch film (200-4) according to the fifth embodiment may be different from the pouch film (200) according to the first embodiment in the first wing region (220') and the second wing region (220''). Specifically, the pouch film (200-4) according to the fifth embodiment may be different from the pouch film (200) according to the first embodiment in the shape of the indentation region (230).

[0144] The pouch film (200-4) according to the fifth embodiment may include a recessed region (230-4) extending from the wing folding edge (120E) to the extension region (240). The recessed region (230-4) may extend in the front-back direction to the extension region (240). The recessed region (230-4) may not extend beyond the extension region (240) in the left-right direction. Through this, even if the pouch film (200-4) has a rectangular shape, a pouch-type battery case (100) can be formed. When the pouch film (200-4) has a rectangular shape, the extension region (240) may be formed at a corner of the pouch film (200-4).

[0145] Furthermore, even if the immersion area (230-4) forms a immersion surface (130) (not shown), it can be used without separate cutting. The pouch film (200-4) according to the fifth embodiment was prepared by modifying the immersion area (230-4) of the first embodiment, but it should be considered that an embodiment in which only the extension area (240) is modified is also disclosed in the present disclosure.

[0146] Example 6

[0147] FIG. 13 is a perspective view illustrating a pouch film (200-5) for forming a pouch-type battery case (100) according to the sixth embodiment.

[0148] Referring to FIG. 13, a pouch-type battery case (100) according to the sixth embodiment is described.

[0149] The pouch-type battery case (100) (not shown) according to the sixth embodiment may be the same as the pouch-type battery case (100) according to the first embodiment. However, there may be a difference in the pouch film (200) for making the pouch-type battery case (100) according to the sixth embodiment. The pouch film (200-5) according to the sixth embodiment may differ from the pouch film (200) according to the first embodiment in the first wing region (220') and the second wing region (220''). Specifically, the pouch film (200) according to the sixth embodiment may differ from the pouch film (200-5) according to the first embodiment in the shapes of the extension region (240-5) and the recessed region (230-5).

[0150] The pouch film (200-5) according to the sixth embodiment may include an extension region (240-5) and a recessed region (230-5) formed in the shape of a right triangle. The extension region (240-5) and the recessed region (230-5) may be formed to share a hypotenuse with each other. Furthermore, the hypotenuses of the extension region (240-5) and the recessed region (230-5) may be formed to overlap with an inclined line (230L). Through this, even if the pouch film (200) has a rectangular shape, a pouch-type battery case (100) can be formed. When the pouch film (200-5) has a rectangular shape, the extension region (240-5) and the recessed region (230-5) may be formed at the corners of the pouch film (200-5).

[0151] The pouch-type battery case (100), secondary battery (1) and / or pouch-type battery case (100) manufacturing method according to one embodiment of the present invention as described above may have the following characteristics.

[0152] A pouch-type battery case (100) according to one embodiment of the present invention is a pouch-type battery case (100) integrally formed to have a receiving space (100S) for receiving an electrode assembly (10), and may include a main folding edge (110E) defining a lower end of the receiving space (100S), a pair of main sealing surfaces (110) facing each other to form the receiving space (100S), and at least one wing portion (120) defining a side of the receiving space (100S) and connected to the main folding edge (110E) and the pair of main sealing surfaces (110).

[0153] The upper portion of the receiving space (100S) may be defined, and a sealing portion (101) formed by a pair of main sealing surfaces (110) being adjacent may be further included.

[0154] At least one wing portion (120) may include a first wing portion (120') extending from one main sealing surface (110), a second wing portion (120'') extending from the other main sealing surface (110), and a wing folding edge (120E) connecting the first wing portion (120') and the second wing portion (120'').

[0155] The wing folding edge (120E) can extend perpendicularly to the extension direction of the main folding edge (110E).

[0156] The first wing portion (120') and the second wing portion (120'') may include an extension surface (140) extending from a pair of main sealing surfaces (110), a recessed surface (130) extending from a wing folding edge (120E) toward the extension surface (140), and an inclined edge (130E) connecting the extension surface (140) and the recessed surface (130).

[0157] The extension surface (140) and the indentation surface (130) can be configured to cover the side of the receiving space (100S) by the length that the inclined edge (130E) extends.

[0158] The wing folding edge (120E) can connect the recessed surface (130) of the first wing part (120') and the recessed surface (130) of the second wing part (120'').

[0159] The extension face (140) can be positioned between the pair of main sealing faces (110) and the recessed face (130) so as to face the pair of main sealing faces (110).

[0160] The extension surface (140) can extend in the extension direction of a pair of main sealing surfaces (110).

[0161] The extension face (140) may include a first extension face segment (141a) extending from a pair of main sealing faces (110) and positioned on a plane along which the pair of main sealing faces (110) extend, and a second extension face segment (141b) folded from the first extension face segment (141a) to cover the first extension face segment (141a) from the outside.

[0162] The slope edge (130E) can meet the main folding edge (110E) and the wing folding edge (120E) at one point.

[0163] The inclined edge (130E) may extend in a direction away from the main folding edge (110E) as it goes upward.

[0164] The inclined edge (130E) can be extended at an angle of 45° to the extension direction of the main folding edge (110E).

[0165] The indentation surface (130) may have a shape corresponding to the extension surface (140).

[0166] The main folding edge (110E) may have a width corresponding to the width of the electrode assembly (10).

[0167] A secondary battery (1) according to one embodiment of the present invention includes a pouch-type battery case (100) integrally formed to have an electrode assembly (10) and a receiving space (100S) for receiving the electrode assembly (10), and the pouch-type battery case (100) may include a main folding edge (110E) defining a lower end of the receiving space (100S), a pair of main sealing surfaces (110) facing the electrode assembly (10), at least one wing portion (120) defining a side of the receiving space (100S) and connected to the main folding edge (110E) and the pair of main sealing surfaces (110) to cover the side of the electrode assembly (10), and a sealing portion (101) defining an upper end of the receiving space (100S) and formed by the pair of main sealing surfaces (110) being adjacent to each other.

[0168] At least one wing portion (120) may include a first wing portion (120') extending from one main sealing surface (110), a second wing portion (120'') extending from the other main sealing surface (110), and a wing folding edge (120E) connecting the first wing portion (120') and the second wing portion (120'').

[0169] The first wing portion (120') and the second wing portion (120'') may include an extension surface (140) extending from a pair of main sealing surfaces (110), a recessed surface (130) extending from a wing folding edge (120E) toward the extension surface (140), and an inclined edge (130E) connecting the extension surface (140) and the recessed surface (130).

[0170] The extension surface (140) can be configured to cover the side of the receiving space (100S) by the length that the inclined edge (130E) extends along with the indentation surface (130).

[0171] A method for manufacturing a pouch-type battery case (100) according to one embodiment of the present invention may include a step of preparing a pouch film (200) having a pair of main sealing areas (210) connected to a main folding boundary (210B) so that the pouch battery case has an accommodation space (100S) and a wing area (220) positioned between the pair of main sealing areas (210), a step of folding the pair of main sealing areas (210) against the main folding boundary (210B) to form a pair of main sealing surfaces (110) configured to face the accommodation space (100S) in the front-rear direction, and a step of forming a wing portion (120) configured to cover a side of the accommodation space (100S) by indenting the wing area (220) toward the accommodation space (100S).

[0172] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, combinations between embodiments may be considered possible, unless one embodiment is explicitly restricted from being combined with another embodiment. Combinations of one embodiment with another embodiment are deemed to be disclosed in this document.

[0173] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. In a pouch-type battery case integrally formed to have a receiving space for receiving an electrode assembly, A pair of main sealing surfaces facing each other to form the accommodation space, connected to the main folding edge defining the bottom of the accommodation space; and A pouch-shaped battery case defining a side of the above-described receiving space and including at least one wing portion connected to the main folding edge and the pair of main sealing surfaces.

2. In paragraph 1, A pouch-shaped battery case defining an upper portion of the above-described receiving space and further including a sealing portion formed by adjoining the pair of main sealing surfaces.

3. In paragraph 1, At least one wing portion, The first wing section extending from the main ceiling surface; A second wing extending from the main sealing surface; and A pouch-shaped battery case including a wing folding edge connecting the first wing portion and the second wing portion.

4. In paragraph 3, A pouch-shaped battery case in which the above wing folding edge extends vertically with respect to the extension direction of the above main folding edge.

5. In paragraph 3, The above first wing section and the above second wing section, An extension surface extending from the above pair of main sealing surfaces; a recessed surface extending from the wing folding edge toward the extension surface; and A pouch-shaped battery case comprising an inclined edge connecting the extended surface and the recessed surface.

6. In paragraph 5, A pouch-shaped battery case in which the above-mentioned extension surface and the recessed surface are configured to cover the side of the receiving space by the length that the above-mentioned inclined edge extends.

7. In paragraph 5, The above wing folding edge is a pouch-shaped battery case that connects the recessed surface of the first wing part and the recessed surface of the second wing part.

8. In paragraph 5, A pouch-shaped battery case in which the above extension surface is positioned between the pair of main sealing surfaces and the recessed surface so as to face the pair of main sealing surfaces.

9. In paragraph 5, A pouch-shaped battery case in which the above extension surface extends in the extension direction of the pair of main sealing surfaces.

10. In paragraph 5, The above extension surface is, A first extension face segment extending from the pair of main sealing faces and positioned on a plane along which the pair of main sealing faces extend; and A pouch-shaped battery case comprising a second extension face segment folded from the first extension face segment to cover the first extension face segment from the outside.

11. In paragraph 5, A pouch-shaped battery case in which the above-mentioned inclined edge meets the above-mentioned main folding edge and the above-mentioned wing folding edge at one point.

12. In paragraph 5, A pouch-shaped battery case in which the above-mentioned inclined edge extends in a direction away from the main folding edge as it goes upward.

13. In paragraph 5, A pouch-shaped battery case in which the above-mentioned inclined edge extends at an angle of 45˚ to the extension direction of the above-mentioned main folding edge.

14. In paragraph 5, A pouch-shaped battery case in which the above-mentioned insertion surface has a shape corresponding to the above-mentioned extension surface.

15. In paragraph 1, A pouch-shaped battery case wherein the main folding edge has a width corresponding to the width of the electrode assembly.

16. Electrode assembly; and A pouch-shaped battery case is formed integrally to have a receiving space for receiving the electrode assembly, The above pouch-type battery case, A pair of main sealing surfaces facing the electrode assembly, connected to the main folding edge defining the lower portion of the above-described receiving space; At least one wing portion connected to the main folding edge and the pair of main sealing surfaces to define a side of the receiving space and cover a side of the electrode assembly; and A secondary battery comprising a sealing portion defining the upper portion of the above-described receiving space and formed by the pair of main sealing surfaces being adjacent to each other.

17. In paragraph 16, At least one wing portion, The first wing section extending from the main ceiling surface; A second wing extending from the main sealing surface; and A secondary battery comprising a wing folding edge connecting the first wing portion and the second wing portion.

18. In paragraph 17, The above first wing section and the above second wing section, An extension surface extending from the above pair of main sealing surfaces; a recessed surface extending from the wing folding edge toward the extension surface; and A secondary battery comprising an inclined edge connecting the extended surface and the recessed surface.

19. In paragraph 18, A secondary battery in which the above-mentioned extension surface is configured to cover the side of the receiving space by the length that the inclined edge extends together with the above-mentioned insertion surface.

20. A step of preparing a pouch film having a pair of main sealing areas connected to a main folding area so that a battery case for a pouch has a receiving space and a wing area positioned between the pair of main sealing areas; A step of folding a pair of main sealing areas relative to the main folding area to form a pair of main sealing surfaces configured to face each other in the front-rear direction of the above-mentioned accommodation space; and A method for manufacturing a pouch-shaped battery case, comprising the step of forming a wing portion configured to cover a side of the receiving space by indenting the wing area toward the receiving space.

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