Pouch-shaped case, secondary battery having the same, manufacturing method, and secondary battery module

Abstract

A pouch case according to an embodiment of the disclosure includes a formation portion having a predetermined depth and allowing each of first and second end surfaces of an electrode assembly to be accommodated therein, a notch portion extending from each of opposite end portions of the formation portion to have a depth gradually decreasing from a depth defined by a thickness of the electrode assembly accommodated in the formation portion, and a storage portion covering a remaining portion except for a portion of the electrode assembly accommodated in the formation portion. According to an embodiment of the disclosure, by effectively controlling a protruding structure of a pouch case sealing on first and second end surfaces of an electrode assembly accommodated therein, it is possible to improve contact reliability between a stacking structure of a pouch-type secondary battery and a cooling plate.

Description

[0001] Cross-applications related to technologies

[0002] This application claims priority to Korean Patent Application No. 10-2020-0087110, filed on July 14, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure relate to a pouch-shaped casing for a secondary battery, a secondary battery, a secondary battery module, and a method for manufacturing a secondary battery. Background Technology

[0004] Secondary battery cells are manufactured in a form where an electrode assembly consisting of a positive electrode, a negative electrode, a separator, and an electrolyte is enclosed in a casing. Electrode assemblies can be categorized into roll-type and stacked types. In the roll-type, sheet-like positive and negative electrodes coated with active material are wound together with separators inserted between them. In the stacked type, multiple positive and negative electrodes are stacked sequentially, with separators inserted between them. The electrode assembly is encapsulated in a container formed by pressing metal material into a cylinder or cuboid, or in a bag made of a multilayer film obtained by extruding polymer raw materials. Bag-type batteries are widely used in various fields due to their low manufacturing cost, low weight, and high formability.

[0005] Examples of conventional pouch-type secondary batteries include electrode assemblies and a pouch-shaped housing for sealing the electrode assemblies. The pouch-shaped housing includes a storage section for storing the electrode assemblies therein and a sealing section for sealing the electrode assemblies.

[0006] Traditional pouch-type secondary batteries are manufactured by storing the electrode assembly in a storage section of a pouch-shaped housing, sealing the outer periphery of the pouch-shaped housing, and then sealing the sides of the pouch-shaped housing to form flat sides. A problem with secondary batteries encapsulated on three sides of this pouch-shaped housing is that when the secondary battery module comes into contact with a cooling plate, the sealing protrusions (known as shark fins) formed at the opposite ends of the flat sides cause unwanted interference. This reduces the cooling efficiency of the secondary battery module or limits the design freedom for handling various other environments. Therefore, a solution to this problem is needed.

[0007] The foregoing is intended only to help understand the background of this disclosure and is not intended to imply that this disclosure falls within the scope of related technologies known to those skilled in the art.

[0008] Literature in related fields

[0009] (Patent Document 1) Korean Patent No. 10-2061664B1 Summary of the Invention

[0010] Accordingly, the present disclosure has been made considering the above-mentioned problems occurring in the prior art, and an object of the present disclosure is to provide a pouch case for accommodating an electrode assembly therein, and to provide a pouch case for effectively controlling unnecessary structural protrusions occurring in a process of accommodating and sealing the electrode assembly.

[0011] Another object of the present disclosure is to provide a pouch case that allows first and second end surfaces of an electrode assembly to be in close contact with the pouch case without being loosened therefrom, and prevents structural separation of the electrode assembly.

[0012] Still another object of the present disclosure is to provide a secondary battery and a secondary battery module in which not only a structural space for stacking and cooling a secondary battery in which an electrode assembly is accommodated in a pouch case is optimized, but also a contact surface with a cooling plate for cooling is effectively secured.

[0013] Still another object of the present disclosure is to provide a method of manufacturing a secondary battery having a pouch case.

[0014] To achieve the above object, according to one aspect of the present disclosure, there is provided a pouch case for a secondary battery, the pouch case including: a formation portion having a predetermined depth and allowing each of first and second end surfaces of an electrode assembly to be accommodated therein; a notch portion extending from each of opposite end portions of the formation portion; and a storage portion covering a portion of the electrode assembly that is not accommodated in the formation portion, wherein the formation portion can include a first formation portion allowing the first end surface of the electrode assembly to be accommodated therein, and a second formation portion allowing the second end surface of the electrode assembly to be accommodated therein.

[0015] Here, the first formation portion can include a first bottom surface having a predetermined depth and the first end surface of the electrode assembly being in contact with the first bottom surface, and a first height portion extending from the first bottom surface to support each of opposite side surfaces of the electrode assembly, and the second formation portion can include a second bottom surface having a predetermined depth and the second end surface of the electrode assembly being in contact with the second bottom surface, and a second height portion extending from the second bottom surface to support each of opposite side surfaces of the electrode assembly.

[0016] Further, each of extension lines of the first and second bottom surfaces and an associated one of the respective notch portions can form an acute angle.

[0017] Further, the notch portion can include a first notch portion extending upward at a predetermined angle from each of the opposite end portions of the first formation portion, and a second notch portion extending upward at a predetermined angle from each of the opposite end portions of the second formation portion.

[0018] Also, the storage portion can include a central storage portion covering the first side surface of the electrode assembly between the first formation portion and the second formation portion, a first storage portion including a first receiving portion covering a portion of the second side surface of the electrode assembly and a first joint portion extending from an end of the first receiving portion to be bendable, and a second storage portion including a second receiving portion covering a remaining portion of the second side surface of the electrode assembly and a second joint portion extending from an end of the second receiving portion to be bendable.

[0019] Also, the first joint portion can extend upward from the first receiving portion to have a height difference with respect to the first receiving portion, and the second joint portion can extend upward from the second receiving portion to have a height difference with respect to the second receiving portion.

[0020] Also, the pouch case can further include a first pressing protrusion protruding inward from the first bottom surface to support the first end surface of the electrode assembly, and a second pressing protrusion protruding inward from the second bottom surface to support the second end surface of the electrode assembly.

[0021] According to another aspect of the disclosure, there is provided a pouch case for a secondary battery, the pouch case including a formation portion having a predetermined depth and allowing each of first and second end surfaces of an electrode assembly to be received therein, a notch portion spaced apart from each of opposite end portions of the formation portion, and a storage portion covering a portion of the electrode assembly that is not received in the formation portion, wherein the formation portion can include a first formation portion allowing the first end surface of the electrode assembly to be received therein, and a second formation portion allowing the second end surface of the electrode assembly to be received therein.

[0022] Here, the first formation portion can include a first bottom surface having a predetermined depth and the first end surface of the electrode assembly being in contact with the first bottom surface, and a first height portion extending from the first bottom surface to support each of opposite side surfaces of the electrode assembly, and the second formation portion can include a second bottom surface having a predetermined depth and the second end surface of the electrode assembly being in contact with the second bottom surface, and a second height portion extending from the second bottom surface to support each of opposite side surfaces of the electrode assembly.

[0023] Also, the notch portion can include a first notch portion having a height difference with respect to the first bottom surface of the first formation portion, and a second notch portion having a height difference with respect to the second bottom surface of the second formation portion.

[0024] Also, the notch portion can include a first notch portion spaced apart from each of opposite end portions of the first formation portion and including a first curved surface having a predetermined curvature in an outward direction of the pouch case, and a second notch portion spaced apart from each of opposite end portions of the second formation portion and including a second curved surface having a predetermined curvature in the outward direction of the pouch case.

[0025] Further, the storage portion can include a central storage portion covering a first side surface of the electrode assembly between the first formation portion and the second formation portion, a first storage portion including a first receiving portion covering a portion of a second side surface of the electrode assembly and a first joint portion extending from an end of the first receiving portion to be bendable, and a second storage portion including a second receiving portion covering a remaining portion of the second side surface of the electrode assembly and a second joint portion extending from an end of the second receiving portion to be bendable.

[0026] Further, the pouch-shaped case can further include a first pressing protrusion protruding inward from the first bottom surface to support the first end surface of the electrode assembly, and a second pressing protrusion protruding inward from the second bottom surface to support the second end surface of the electrode assembly.

[0027] According to still another aspect of the disclosure, a secondary battery is provided, including an electrode assembly, and a pouch-shaped case in which the electrode assembly is accommodated, wherein the pouch-shaped case can include a formation portion having a predetermined depth and including a first formation portion allowing a first end surface of the electrode assembly to be accommodated therein and a second formation portion allowing a second end surface of the electrode assembly to be accommodated therein, a notch portion extending from or spaced apart from each of opposite end portions of the formation portion, and a storage portion covering a portion of the electrode assembly not accommodated in the formation portion.

[0028] Here, the storage portion can include a central storage portion covering a first side surface of the electrode assembly between the first formation portion and the second formation portion, a first storage portion including a first receiving portion covering a portion of a second side surface of the electrode assembly and a first joint portion extending from an end of the first receiving portion and bending outward of the electrode assembly, and a second storage portion including a second receiving portion covering a remaining portion of the second side surface of the electrode assembly and a second joint portion extending from an end of the second receiving portion and bending outward of the electrode assembly.

[0029] Further, the first joint portion and the second joint portion can bend outward of the second side surface of the electrode assembly in a manner of surface-contacting each other.

[0030] According to still another aspect of the disclosure, a secondary battery module is provided, including: at least two secondary batteries stacked in a first side surface direction, wherein the secondary batteries can be arranged to be spaced apart from each other at a predetermined interval, and each of the secondary batteries can include: an electrode assembly; and a pouch-shaped case in which the electrode assembly is accommodated, wherein the pouch-shaped case can include: a formed portion having a predetermined depth and including a first formed portion allowing a first end surface of the electrode assembly to be accommodated therein and a second formed portion allowing a second end surface of the electrode assembly to be accommodated therein; a notch portion extending from or spaced apart from each of opposite end portions of the formed portion; and a storage portion covering a portion of the electrode assembly that is not accommodated in the formed portion.

[0031] Here, the secondary battery module can further include: a cooling plate disposed on the first formed portion or the second formed portion of each of the secondary batteries.

[0032] Further, the cooling plate can include: a first cooling plate in surface contact with the first formed portion; and a second cooling plate in surface contact with the second formed portion.

[0033] Further, the secondary battery module can further include: an insulating material disposed in the predetermined interval.

[0034] According to still another aspect of the disclosure, a method of manufacturing a secondary battery is provided, the method including: forming a first formed portion and a second formed portion in a pouch-shaped case such that the first formed portion and the second formed portion are spaced apart from each other; coupling a first end surface of an electrode assembly to the first formed portion; coupling a central storage portion between the first formed portion and the second formed portion to a first side surface of the electrode assembly to cover the first side surface of the electrode assembly by the central storage portion; coupling a second end surface of the electrode assembly to the second formed portion; and coupling a second storage portion extending from the second formed portion to a portion of a second side surface of the electrode assembly to cover the portion of the second side surface of the electrode assembly by the second storage portion, and coupling a first storage portion extending from the first formed portion to a remaining portion of the second side surface of the electrode assembly to cover the remaining portion of the second side surface of the electrode assembly by the first storage portion.

[0035] Here, the method can further include: after coupling the first storage portion to the portion of the second side surface of the electrode assembly and coupling the second storage portion to the remaining portion of the second side surface of the electrode assembly, joining a first bendable joint at an end portion of the first accommodation portion to a second bendable joint at an end portion of the second accommodation portion to each other; and bending a seal joint in one direction on the second side surface of the electrode assembly, the seal joint being generated by the joining of the first joint and the second joint.

[0036] Further, the step of forming the first and second formed portions in the pouch-shaped case so as to be spaced apart from each other can include forming first and second notch portions, the first notch portion extending from each of opposite end portions of the first formed portion in a direction in which the first formed portion is formed, and the second notch portion extending from each of opposite end portions of the second formed portion in a direction in which the second formed portion is formed.

[0037] Further, the step of forming the first and second formed portions in the pouch-shaped case so as to be spaced apart from each other can include forming first and second notch portions, the first notch portion extending from each of opposite end portions of the first formed portion in a direction in which the first formed portion is formed, and the second notch portion extending from each of opposite end portions of the second formed portion in a direction in which the second formed portion is formed.

[0038] All terms or words used in the description and claims, unless explicitly stated otherwise, have the same meaning as commonly understood by one of ordinary skill in the art in which this disclosure resides. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0039] According to embodiments of the present disclosure, by effectively controlling the protruding structure of the pouch-shaped case sealed on the first and second end surfaces of the battery assembly accommodated therein, it is possible to improve the contact reliability between the stacking structure of the pouch-type secondary battery and the cooling plate.

[0040] In addition, by effectively controlling the protrusion of the sealing portion on each of the opposite end portions of the pouch-type secondary battery while covering the first and second end surfaces of the electrode assembly, it is possible to effectively secure the contact surface with the cooling plate on the opposite end portions of the pouch-type secondary battery. Thereby, it is possible to improve the cooling efficiency of the secondary battery module and the battery pack having the same, as well as the design freedom of the cooling structure.

[0041] In addition, in order to effectively reduce and control the coupling error or tolerance that can occur in the process of accommodating and sealing the electrode assembly in the pouch-shaped case, by physically supporting and pressing the opposite upper and lower end surfaces of the electrode assembly via the pressing protrusion partially protruding from the bottom surface of the formed portion of the pouch-shaped case, it is possible to prevent the electrode assembly from being loose when accommodated in the pouch-shaped case, thereby securing the reliability of the electrode assembly when accommodated in the pouch-shaped case and sealed.

[0042] In addition, by effectively removing and controlling the protruding structure of the sealing joint that can occur in the process of sealing the electrode assembly by the pouch-shaped case, it is not only possible to further improve the energy density of the secondary battery module configuration, but also to increase the design freedom for implementing various stacking structures. Attached Figure Description

[0043] The above and other objects, features and other advantages of this disclosure will become more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0044] Figure 1 This is an exploded perspective view of the bag-shaped housing and electrode assembly according to an embodiment of the present disclosure;

[0045] Figure 2 This is an assembled perspective view of the bag-shaped housing and electrode assembly according to an embodiment of the present disclosure;

[0046] Figure 3 This is a perspective view of a bag-shaped housing according to an embodiment of the present disclosure;

[0047] Figure 4 It is along Figure 3 A cross-sectional view taken from A-A';

[0048] Figure 5 This is a cross-sectional view of a secondary battery having a pouch-shaped casing according to an embodiment of the present disclosure;

[0049] Figure 6A and Figure 6B This is a view of a traditional pouch-type secondary battery;

[0050] Figure 7 This is a plan view of a secondary battery having a pouch-shaped housing in which electrode assemblies are housed, according to an embodiment of the present disclosure.

[0051] Figure 8A and Figure 8B This is a schematic diagram of the coupling between the secondary battery and the cooling plate of the secondary battery module according to an embodiment of the present disclosure;

[0052] Figure 9 This is an exploded perspective view of a bag-shaped housing and an electrode assembly according to another embodiment of the present disclosure;

[0053] Figure 10 This is an assembled perspective view of the bag-shaped housing and electrode assembly according to other embodiments of this disclosure;

[0054] Figure 11 This is a perspective view of a bag-shaped housing according to another embodiment of the present disclosure;

[0055] Figure 12 It is along Figure 11 A cross-sectional view taken from A-A';

[0056] Figure 13 This is a cross-sectional view of a secondary battery having a pouch-shaped casing according to another embodiment of the present disclosure;

[0057] Figure 14 is an exploded perspective view of a pouch case and an electrode assembly according to another embodiment of the disclosure;

[0058] Figure 15 is an assembled perspective view of a pouch case and an electrode assembly according to other embodiments of the disclosure;

[0059] Figure 16 is a perspective view of a pouch case according to other embodiments of the disclosure;

[0060] Figure 17 is a cross-sectional view taken along A-A' of Figure 16

[0061] Figure 18 is a cross-sectional view taken along B-B' of Figure 16

[0062] Figure 19 is a side cross-sectional view of coupling of a pouch case and an electrode assembly according to other embodiments of the disclosure;

[0063] Figure 20 is a plan view of an example of a bottom surface of a forming portion of a pouch case according to an embodiment of the disclosure;

[0064] Figure 21 is a cross-sectional view taken along A-A' of Figure 20

[0065] Figure 22 is a plan view of another example of a bottom surface of a forming portion of a pouch case according to an embodiment of the disclosure;

[0066] Figure 23 is a cross-sectional view taken along B-B' of Figure 22

[0067] Figure 24 to Figure 28 is a flowchart of a method of manufacturing a secondary battery according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0068] The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals refer to like elements throughout. With respect to the drawings, like reference numerals refer to like elements throughout the various figures and like reference numerals are used to designate like elements throughout the specification and in the various figures. In addition, it should be understood that, although the terms "first", "second", "third", and the like can be used herein to describe various elements, these elements should not be limited by these terms. The details of well-known features and techniques are omitted in the following description for the sake of clarity and conciseness.

[0069] ​​​​Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In all the drawings, like reference numerals will denote like elements or components.

[0070] Figure 1 is an exploded perspective view of a pouch-shaped case and an electrode assembly according to an embodiment of the present disclosure; Figure 2 is an assembled perspective view of a pouch-shaped case and an electrode assembly according to an embodiment of the present disclosure; Figure 3 is a perspective view of a pouch-shaped case according to an embodiment of the present disclosure; Figure 4 is a cross-sectional view taken along Figure 3 A-A' of FIG. 10; Figure 4 is a cross-sectional view of a secondary battery having a pouch-shaped case according to an embodiment of the present disclosure; Figure 5 and Figure 6A are views of a conventional pouch-type secondary battery; Figure 6B is a plan view of a secondary battery having a pouch-shaped case in which an electrode assembly is accommodated according to an embodiment of the present disclosure; and Figure 7 and Figure 8A are schematic views of coupling of a secondary battery and a cooling plate of a secondary battery module according to an embodiment of the present disclosure.

[0071] The pouch-shaped case 30 according to an embodiment of the present disclosure includes a formation portion 32 having a predetermined depth and allowing each of first and second end surfaces of the electrode assembly 10 to be accommodated therein, a notch portion 34 extending from each of opposite end portions of the formation portion 32 to have a depth gradually decreasing from a depth defined by a thickness of the electrode assembly 10 accommodated in the formation portion 32, and a storage portion 33 covering a remaining portion except for a portion of the electrode assembly 10 accommodated in the formation portion 32.

[0072] As shown in Figure 8B and Figure 9 , the pouch-shaped case 30 according to an embodiment of the present disclosure is characterized in that the formation portion 32 includes first and second formation portions 321 and 322 coupled to the first and second end surfaces (upper and lower end surfaces in the drawing) of the electrode assembly 10, respectively, and the notch portion 34 includes first and second notch portions 341 and 342 formed at each of longitudinally opposite end portions of the first formation portion 321 and each of longitudinally opposite end portions of the second formation portion 321, respectively, thereby minimizing protrusion or structural deformation due to unnecessary sealing engagement on the first and second end surfaces (i.e., upper and lower end surfaces) of the electrode assembly 10 sealed by the first and second formation portions 321 and 322.

[0073] As shown in Figure 10 and Figure 11As shown, the pouch-shaped case 30 according to the embodiment of the present disclosure is configured such that the first formation portion 321 and the second formation portion 322 are spaced apart from each other in the lateral direction, so that the first end surface of the electrode assembly 10 and the second end surface opposite to the first end surface are fixedly coupled to respective predetermined positions within the sealing portion 31 formed along the outer periphery of the pouch-shaped case 30.

[0074] The first formation portion 321 is formed in one direction on one side of the internal space defined within the sealing portion 31 of the pouch-shaped case 30 to allow the first end surface of the electrode assembly 10 to be positioned therein. The opposite side of the first formation portion 321 can be curved upward at a predetermined angle to form a predetermined position, so that the first end surface of the electrode assembly 10 can be fixed or its position can be determined.

[0075] In the embodiment of the present disclosure, as shown in Figure 12 and Figure 11 The first formation portion 321 can include a first bottom surface 321a that allows a portion of the first end portion of the electrode assembly 10 to be received thereon, and a first height portion 321b that extends upward from each of the opposite sides of the first bottom surface 321a to support each of the opposite side surfaces of the electrode assembly 10.

[0076] The second formation portion 322 is a configuration that allows the second end surface of the electrode assembly 10 opposite to the first end surface thereof to be received and coupled thereto, and can have the same shape and structure as the above-described first formation portion 321. In addition, since the first formation portion 321 and the second formation portion 322 are coupled to the first end surface and the second end surface of the electrode assembly 10 to fix and receive the electrode assembly at respective corresponding positions, the first formation portion 321 and the second formation portion 322 can be configured to have the same structure and shape, which can effectively receive the electrode assembly 10 in the pouch-shaped case 30.

[0077] The storage portion 33 includes a first storage portion 331, a central storage portion 332, and a second storage portion 333 sequentially formed with respect to the first formation portion 321 and the second formation portion 322 of the pouch-shaped case 30. The storage portion 33 covers the opposite side surfaces of the electrode assembly 10, and is finally sealed while surrounding the side surfaces of the electrode assembly 10 to allow the electrode assembly 10 to be received in the pouch-shaped case 30.

[0078] The central storage portion 332 between the first formation portion 321 and the second formation portion 322 completely receives and covers the first side surface of the electrode assembly 10, and the first storage portion 331 and the second storage portion 333 at positions outside the first formation portion 321 and the second formation portion 322 overlap each other on the second side surface of the electrode assembly 10 to be sealed and joined together.

[0079] As shown in Figure 13As shown, the first storage portion 331 includes a first receiving portion 331a covering a portion of the second side surface of the electrode assembly 10 and a first joint portion 331b extending from the first storage portion 331 so as to be bendable and used for final sealing and joining. Here, the first receiving portion 331a can be configured to have a height difference with respect to the first joint portion 331b, thereby having an inner space to facilitate assembly when covering the electrode assembly 10, or to be flexibly responsive to the shape of the electrode assembly 10. When the first receiving portion 331a naturally covers a portion of the second side surface of the electrode assembly 10, the first joint portion 331b can be bent outward from the second side surface of the electrode assembly 10 and finally joined to the second joint portion 333b of the second storage portion 333, thereby facing the second joint portion 333b in a surface contact manner, thereby sealing the pouch case 30.

[0080] The second storage portion 333 extends outward from the second formation portion 322 and covers a portion of the second side surface of the electrode assembly 10 when the second formation portion 322 receives the second end surface of the electrode assembly 10. The second storage portion 333 includes a second receiving portion 333a covering a portion of the second side surface of the electrode assembly 10 and a second joint portion 333b extending from the second receiving portion 333a so as to be bendable. The second joint portion 333b is joined to the above-described first joint portion 331b of the first storage portion 331, thereby facing the first joint portion 331b in a surface contact manner, thereby sealing the pouch case 30.

[0081] As shown, Figure 9 The first joint portion 331b and the second joint portion 333b can be bent outward of the second side surface of the electrode assembly 10, surface-contacting each other. According to an example, the first joint portion 331b and the second joint portion 333b can be joined to each other by a sealing method to form a surface contact therebetween, but are not limited thereto. In the present disclosure, by bending the first joint portion 331b and the second joint portion 333b in an outward direction of the second side surface of the electrode assembly 10, unnecessary wasted space can be prevented.

[0082] The notch portion 34 can include a first notch portion 341 and a second notch portion 342 formed at each of the longitudinally opposite end portions of the first formation portion 321 and each of the longitudinally opposite end portions of the second formation portion 322, respectively.

[0083] As shown, Figure 10 The respective first notch portions 341 can be formed at the longitudinally opposite end portions of the first formation portion 321, and the respective second notch portions 342 can be formed at the longitudinally opposite end portions of the second formation portion 322.

[0084] As shown, Figure 11 and Figure 12As shown, a conventional pouch-type secondary battery 10 includes an electrode assembly 1 and a pouch-shaped housing 2 for sealing the electrode assembly 1. The pouch-shaped housing 2 includes a storage portion 2a for storing the electrode assembly 1 therein and a sealing portion 2b for sealing the electrode assembly 1. When the conventional pouch-type secondary battery 10 is coupled to the cooling plate of a battery module, Figure 13 The sealing protrusion 3 shown, referred to as the shark fin, causes interference with the cooling plate, which may lead to problems not only deterioration in cooling efficiency but also deterioration in the energy density of the battery module.

[0085] However, as Figure 14 As shown, the secondary battery 100 with a pouch-shaped housing 30 according to an embodiment of the present disclosure does not have protrusions formed on the side surface of the pouch-shaped housing 30, so when coupled to the cooling plate 50 of the secondary battery module 1, which will be described later, it can make surface contact with it, thereby improving cooling efficiency.

[0086] Furthermore, by providing the notch 34 in the bag-shaped housing 30, the shape and size of the sealing protrusion can be controlled. Additionally, by forming a predetermined gap distance D with the cooling plate 50, the coupling surface with the cooling plate 50 can be effectively ensured.

[0087] Specifically, each first notch 341 can be formed at the opposite ends of the first forming portion 321 by extending upwardly from the opposite ends of the first bottom surface 321a of the first forming portion 321 toward the sealing portion 31 of the bag-shaped housing 30. The first notch 341 covers the longitudinal side surface of the electrode assembly 10 at the position of the opposite ends of the first forming portion 321 and allows the bag-shaped housing 30 to be effectively folded, and is not limited in shape to those shown in the figures. The first notch 341 can be constructed in various lengths and orientations to eliminate structural imbalances in the bag-shaped housing 30 caused by sealing on the longitudinal side surface of the electrode assembly 10, such as irregular protrusions or overlaps. The second notch 342 also has the same construction and effect as the first notch 341, and its detailed description would be redundant and will therefore be omitted.

[0088] like Figure 15 As shown, by providing the forming part 32, the secondary battery module 1 with the pouch-shaped housing 30 according to the embodiment of the present disclosure enables the secondary battery 100 to make surface contact with the cooling plate 50 on its upper and lower surfaces without interfering with it due to the protrusion of the pouch-shaped housing 30, thereby improving the cooling efficiency.

[0089] In addition, by the first and second engaging portions 331b and 333b on the second side surface in the outward direction of the electrode assembly 10, a space having a predetermined interval can be formed between the stacked secondary batteries 100. That is, since the first and second engaging portions 331b and 333b can be curved outward from the second side surface of the electrode assembly 10 in contact with the surface thereof, the secondary batteries 100 can be stacked in the direction of the first side surface and arranged to be spaced apart from each other at a predetermined interval. The predetermined interval can serve as an appropriate buffer to resist deformation or swelling occurring in the stacking direction when the secondary batteries 100 are stacked.

[0090] As Figure 16 indicated, the interval can be used for a cooling function by inflow and outflow of air or circulation of a refrigerant, or can serve as a space in which an insulating material I is filled to inhibit heat propagation.

[0091] Figure 17 is an exploded perspective view of a pouch case and an electrode assembly according to another embodiment of the disclosure; Figure 16 is an assembled perspective view of a pouch case and an electrode assembly according to other embodiments of the disclosure; Figure 18 is a perspective view of a pouch case according to other embodiments of the disclosure;

[0092] Figure 16 is a cross-sectional view taken along A-A' of Figure 19 ; and Figure 14 to Figure 19 is a cross-sectional view of a secondary battery having a pouch case according to another embodiment of the disclosure.

[0093] As Figure 14 and Figure 15 indicated, the pouch case 30 according to an embodiment of the disclosure includes a first formation portion 321, a second formation portion 322, a first notch portion 341, and a second notch portion 342, but is different from the foregoing embodiments in that the storage portion 33 is disposed on the same plane as the sealing portion 31 on the outer periphery of the pouch case 30, without a height difference between the sealing portion 31 and the internal space.

[0094] As Figure 16 and Figure 17 indicated, the electrode assembly 10 is accommodated in the pouch case 20, the first formation portion 321, the second formation portion 322, the first notch portion 341, and the second notch portion 342 can be formed on the same plane, without a height difference from the sealing portion 31 on the outer periphery of the pouch case at which sealing is performed, so that the first storage portion 331, the central storage portion 332, and the second storage portion 333 can cover the electrode assembly 10 on the same plane.

[0095] The first and second engagement portions 331b and 333b formed at opposite end portions of the pouch case 30 can be finally engaged and sealed on the second side surface of the electrode assembly 10 to form a sealed joint 31a, thereby facilitating sealing of the inside of the pouch case 30 in which the electrode assembly 10 is accommodated.

[0096] As shown in Figure 18 , the first and second engagement portions 331b and 333b can be engaged with each other in surface contact with each other while covering the electrode assembly 10 in opposite directions on the second side surface of the electrode assembly 10, so that the electrode assembly 10 can be accommodated in and sealed by the pouch case 30. The connection portions 331b and 333b formed at opposite end portions of the pouch case 30 can be configured to be bendable, whereby the sealed joint 31a can be bent after final sealing, thereby effectively preventing damage to the pouch case 30. Effects and descriptions related thereto are the same as those described with reference to Figure 18 and Figure 19 The above description described above is redundant, and thus a detailed description thereof will be omitted.

[0097] Figure 20 is an exploded perspective view of a pouch case and an electrode assembly according to another embodiment of the disclosure; Figure 21 is an assembled perspective view of a pouch case and an electrode assembly according to other embodiments of the disclosure; Figure 20 is a perspective view of a pouch case according to other embodiments of the disclosure; Figure 22 is a cross-sectional view taken along A-A' of Figure 23 ; Figure 22 is a cross-sectional view taken along B-B' of Figure 20 to Figure 23 ; and Figure 21 is a one-side cross-sectional view of coupling of a pouch case and an electrode assembly according to another embodiment of the disclosure.

[0098] As shown in Figure 20 , the pouch case 30 according to other embodiments of the disclosure is configured such that the first formation portion 321 and the first notch portion 341 and the second formation portion 322 and the second notch portion 342 are respectively arranged to be spaced apart from each other.

[0099] Other corresponding configurations and operations are substantially the same as those of the pouch case 30 according to the embodiments of the disclosure described above, and thus a repeated description will be omitted.

[0100] As shown in Figure 21As shown, the pouch-shaped case 30 according to an embodiment of the disclosure can include a first formation portion 321 formed in one direction to allow the first end surface of the electrode assembly 10 to be fixedly and supportively coupled thereto, a central storage portion 332 extending from the first formation portion 321 to cover the first side surface of the electrode assembly 10, a second formation portion 322 formed in one direction by extending from the central storage portion 332 to allow the second end surface of the electrode assembly 10 to be fixedly and supportively coupled thereto, a second accommodation portion 333 extending from the second formation portion 322 to cover a portion of the second side surface of the electrode assembly 10, a first storage portion 331 extending from the first formation portion 321 to cover the remaining portion of the second side surface of the electrode assembly 10 such that the first storage portion 331 and the second storage portion 333 are joined and sealed in a direction facing each other, a first notch portion 341 spaced apart in one direction from each of the opposite end portions of the first formation portion 321 in the extending direction of the first formation portion 321 and adhered in one direction to the corresponding surface of the electrode assembly facing thereto, and a second notch portion 342 spaced apart in one direction from each of the opposite end portions of the second formation portion 322 in the extending direction of the second formation portion 322 and adhered in one direction to the corresponding surface of the electrode assembly facing thereto.

[0101] As shown in Figure 22 and Figure 23 , the notch portions 341 and 342 can include first curved surfaces 341a and second curved surfaces 342a having a predetermined curvature in the outward direction of the pouch-shaped case 30. However, the disclosure is not necessarily limited to the curved shape, and various shapes and structures can be employed within the scope in which the object of the embodiments of the disclosure can be achieved.

[0102] The first curved surfaces 341a and the second curved surfaces 342a having a predetermined curvature can effectively cover the corresponding longitudinal side surfaces of the electrode assembly 10, so that the surface of the formation portion 32 accommodating the electrode assembly 10 can form a flat surface.

[0103] As shown in Figure 24 to Figure 28 and Figure 24 , each first notch portion 341 is spaced apart from the opposite end portions of the first formation portion 321 in one direction in which the first formation portion 321 is formed. Specifically, the first notch portion 341 can have a height difference with respect to the first bottom surface 321a of the first formation portion 321 and can be spaced apart from the first height portion 321b (see reference numeral S in Figure 25 ).

[0104] As shown in Figure 26As shown, the first end face of the electrode assembly 10 can be received and fixed to the first forming portion 321. Since the second forming portion 322 can receive and fix the second end face of the electrode assembly 10, the pouch-shaped housing 30 can seal the electrode assembly 10, so that the entire side surface of the electrode assembly 10 can be covered by the storage portion 33. Its detailed description is substantially the same as that of the pouch-shaped housing 30 according to the embodiment of the present disclosure described above, and the specific method will be described later in the method of manufacturing a secondary battery.

[0105] Figure 27 This is a plan view of an example of the bottom surface of the forming portion of the bag-shaped shell according to an embodiment of the present disclosure; Figure 28 It is along Figure 8A A cross-sectional view taken from A-A'; Figure 8B This is a plan view of another example of the bottom surface of the forming portion of the bag-shaped housing according to an embodiment of the present disclosure; and ​ It is along ​ The cross-sectional view taken from B-B'.

[0106] according to ​ In the illustrated embodiment, the bag-shaped housing 30 may include a first compression protrusion 321c and a second compression protrusion 322c. Therefore, this prevents loosening or separation between the bag-shaped housing 30 and the first or second end face of the electrode assembly 10 during the process of simultaneously coupling and securing the first and second end faces of the electrode assembly 10 to predetermined positions on the bag-shaped housing 30, while maintaining cooling efficiency.

[0107] The first extrusion protrusion 321c can protrude inward from the first bottom surface 321a to support the first end face of the electrode assembly 10, and the second extrusion protrusion 322c can protrude inward from the second bottom surface 322a to support the second end face of the electrode assembly 10.

[0108] For example, the first extrusion protrusion 321c and the second extrusion protrusion 322c can be constructed as uneven portions. More specifically, as... ​ As shown in the enlarged view, each of the first pressing protrusion 321c and the second pressing protrusion 322c can be configured such that the upper surfaces A1 and A2 protruding from the bottom surface and the lower surfaces B1, B2 and B3 forming the bottom surface form a flat surface. Therefore, the bag-shaped housing 30 can ensure contact surfaces with the electrode assembly 10 housed therein, and simultaneously ensure contact surfaces with the cooling plate 50 coupled to its exterior, thereby effectively maintaining cooling efficiency. That is, by allowing the bag-shaped housing 30 to cover the electrode assembly 10 while physically applying predetermined pressure to the upper and lower portions (i.e., the first and second end faces) of the electrode assembly 10 in a direction facing each other, vibrations and noise caused by loosening or internal separation of the electrode assembly 10 sealed within the internal space of the bag-shaped housing 30, as well as other risks such as electrical fires, can be fundamentally prevented.

[0109] As ​ and ​ shown, the plurality of first pressing protrusions 321c and the plurality of second pressing protrusions 322c can be arranged in parallel to be intermittently spaced apart from each other in the longitudinal direction of the first bottom surface 321a of the first formation portion 321 and the second bottom surface 322a of the second formation portion 322, respectively. In addition, as ​ and ​ shown, the first pressing protrusions 321c and the second pressing protrusions 322c can be configured as a continuous protrusion of a corresponding shape that extends in the longitudinal direction of the first bottom surface 321a of the first formation portion 321 and the second bottom surface 322a of the second formation portion 322, respectively.

[0110] In the first pressing protrusions 321c and the second pressing protrusions 322c shown here, although the contact surfaces A1 and A2 with the electrode assembly 10 accommodated and coupled inside the pouch case 30 and the contact surfaces B1, B2, and B3 with the cooling plate 50 coupled outside the pouch case 30 are shown in a plan view, the physical structure can be appropriately changed according to the specifications of the product or the structure of the device.

[0111] ​ is a flowchart of a method of manufacturing a secondary battery according to an embodiment of the disclosure.

[0112] The method of manufacturing a secondary battery according to an embodiment of the disclosure includes forming a first formation portion 321 and a second formation portion 322 spaced apart from each other in a pouch case 30; coupling a first end surface of an electrode assembly 10 to the first formation portion 321; coupling a central reservoir portion 332 between the first formation portion 321 and the second formation portion 322 to a first side surface of the electrode assembly 10 to cover the first side surface of the electrode assembly 10 by the central reservoir portion 332; coupling a second accommodation portion 333a of a second reservoir portion 333 extending from the second formation portion 322 to a portion of a second side surface of the electrode assembly 10 to cover the portion of the second side surface of the electrode assembly 10 by the second accommodation portion 333a; coupling a first accommodation portion 331a of a first reservoir portion 331 extending from the first formation portion 321 to a remaining portion of the second side surface of the electrode assembly 10 to cover the remaining portion of the second side surface of the electrode assembly 10 by the first accommodation portion 331a; joining a first bendable joint portion 331b at an end of the first accommodation portion 331a and a second bendable joint portion 333b at an end of the second accommodation portion 333a to each other; and bending a sealing joint 31a in one direction on the second side surface of the electrode assembly 10, the sealing joint being generated by the joining of the first bendable joint portion 331b and the second bendable joint portion 333b.

[0113] As ​As shown, the first forming portion 321 and the second forming portion 322 can be formed in the bag-shaped housing 30, and the first end face of the electrode assembly 10 can be coupled to the first forming portion 321.

[0114] Next, as ​ As shown, the first forming portion 321 can be coupled to the first end face of the electrode assembly 10. Since the central storage portion 332 extending from the first forming portion 321 can accommodate the first side surface of the electrode assembly 10 to cover the first side surface, the second end face of the electrode assembly 10 can be positioned to be coupled to the second forming portion 322.

[0115] Next, as ​ and ​ As shown, since the second end face of the electrode assembly 10 can be accommodated and coupled to the second forming portion 322, the second receiving portion 333a of the second storage portion 333 can cover a portion of the second side surface of the electrode assembly 10, and the first receiving portion 331a of the first storage portion 331 can cover the remaining portion of the second side surface of the electrode assembly 10 in a direction opposite to the direction in which the second receiving portion 333a covers a portion of the second side surface of the electrode assembly 10. Here, the first joining portion 331b extending from the first receiving portion 331a and bending outward and the second joining portion 333b extending from the second receiving portion 333a and bending outward can be coupled to each other to overlap and join each other in opposite directions, thereby sealing the electrode assembly 10 in the bag-shaped housing 30 to finally seal the electrode assembly 10.

[0116] Next, as ​ As shown, the sealing joint 31a where the first joint 331b and the second joint 333b engage with each other can be bent in one direction, thereby minimizing the space on the stacked surface while ensuring proper spacing. This provides a buffer against physical deformation of the secondary battery 100 in the stacking direction. Additionally, this spacing can be used for cooling functions via air inflow and outflow or refrigerant circulation, or it can be used as a space to be filled with insulating material to suppress heat transfer (see [link to documentation]). ​ and ​ ).

[0117] The first forming portion 321 and the second forming portion 322, spaced apart from each other in the bag-shaped housing 30, may include: forming a first notch 341 extending from each of the opposite ends of the first forming portion 321 in a direction forming the first forming portion 321, and a second notch 342 extending from each of the opposite ends of the second forming portion 322 in a direction forming the second forming portion 322. Furthermore, the first notch 341 and the second notch 342 may be formed to be spaced apart from each of the opposite ends of the first forming portion 321 and the opposite ends of the second forming portion 322, respectively, in a direction.

[0118] In addition, in the method of manufacturing a secondary battery according to the embodiment of the disclosure, the related configuration and operation of the pouch-shaped case 30 according to the embodiment of the disclosure can be applied in the same manner, and thus redundant detailed description thereof will be omitted.

[0119] Although the exemplary embodiments of the disclosure have been described above, the embodiments are only examples of the disclosure, and those skilled in the art will understand that the disclosure can be modified or changed in various forms without departing from the technical spirit of the disclosure. Simple modifications or changes of the disclosure belong to the scope of the disclosure, and the detailed scope of the disclosure will be more clearly understood by the appended claims.

Claims

1. A pouch-shaped housing for a secondary battery, the pouch-shaped housing comprising: A forming portion having a predetermined depth, and allowing each of the first end face and the second end face of the electrode assembly to be accommodated therein; A notch that extends from each of the opposite ends of the formed portion; as well as A storage section that covers the portion of the electrode assembly not contained in the forming section. The forming portion includes: a first forming portion that allows a first end face of the electrode assembly to be received therein; and a second forming portion that allows a second end face of the electrode assembly to be received therein. The storage section includes: A central storage section that covers the first side surface of the electrode assembly between the first forming section and the second forming section; A first storage portion, comprising a first receiving portion covering a portion of a second side surface of the electrode assembly and a first engaging portion extending from an end of the first receiving portion to be flexible; and The second storage portion includes a second receiving portion covering the remaining portion of the second side surface of the electrode assembly and a second engaging portion extending from the end of the second receiving portion to be flexible. The first and second joints are joined to make surface contact with each other on the second side surface of the electrode assembly and bend outward toward the second side surface.

2. The bag-shaped shell according to claim 1, wherein, The first forming portion includes: A first bottom surface having a predetermined depth, and a first end face of the electrode assembly contacting the first bottom surface; and a first height portion extending from the first bottom surface to support each of the opposite side surfaces of the electrode assembly, and The second forming section includes: A second bottom surface having a predetermined depth, and a second end face of the electrode assembly contacting the second bottom surface; and a second height portion extending from the second bottom surface to support each of the opposite side surfaces of the electrode assembly.

3. The bag-shaped shell according to claim 2, wherein, Each of the extensions of the first bottom surface and the second bottom surface forms an acute angle with an associated notch in the respective notch portion.

4. The bag-shaped shell according to claim 1, wherein, The notch includes: A first notch, which extends upward at a predetermined angle from each of the opposite ends of the first forming portion; and The second notch extends upward at a predetermined angle from each of the opposite ends of the second forming portion.

5. The bag-shaped shell according to claim 1, wherein, The first joint extends upward from the first receiving portion to have a height difference relative to the first receiving portion, and The second joint extends upward from the second receiving portion to have a height difference relative to the second receiving portion.

6. The bag-shaped housing according to claim 2, further comprising: A first extrusion protrusion protrudes inward from the first bottom surface to support the first end face of the electrode assembly; as well as A second extrusion protrusion protrudes inward from the second bottom surface to support the second end face of the electrode assembly.

7. A pouch-shaped housing for a secondary battery, the pouch-shaped housing comprising: A forming portion having a predetermined depth, and allowing each of the first end face and the second end face of the electrode assembly to be accommodated therein; A notch portion, which is spaced apart from each of the opposite ends of the formed portion; as well as A storage section that covers the portion of the electrode assembly not contained in the forming section. The forming portion includes: a first forming portion that allows a first end face of the electrode assembly to be received therein; and a second forming portion that allows a second end face of the electrode assembly to be received therein. The storage section includes: A central storage section that covers the first side surface of the electrode assembly between the first forming section and the second forming section; A first storage portion, comprising a first receiving portion covering a portion of a second side surface of the electrode assembly and a first engaging portion extending from an end of the first receiving portion to be flexible; and The second storage portion includes a second receiving portion covering the remaining portion of the second side surface of the electrode assembly and a second engaging portion extending from the end of the second receiving portion to be flexible. The first storage portion and the second storage portion wrap around the electrode assembly from opposite directions on the second side surface, and the first joint portion and the second joint portion are joined to make surface contact with each other and bend outwards towards the second side surface.

8. The bag-shaped housing according to claim 7, wherein, The first forming portion includes: A first bottom surface having a predetermined depth, and a first end face of the electrode assembly contacting the first bottom surface; and a first height portion extending from the first bottom surface to support each of the opposite side surfaces of the electrode assembly, and The second forming section includes: A second bottom surface having a predetermined depth, and a second end face of the electrode assembly contacting the second bottom surface; and a second height portion extending from the second bottom surface to support each of the opposite side surfaces of the electrode assembly.

9. The bag-shaped housing according to claim 8, wherein, The notch includes: The first notch has a height difference relative to the first bottom surface of the first formed portion, and The second notch has a height difference relative to the second bottom surface of the second forming portion.

10. The bag-shaped housing according to claim 8, wherein, The notch includes: A first notch, spaced apart from each of the opposite ends of the first forming portion, and including a first curved surface having a predetermined curvature in the outward direction of the bag-shaped housing; and The second notch is spaced apart from each of the opposite ends of the second forming portion and includes a second curved surface having a predetermined curvature in the outward direction of the bag-shaped housing.

11. The bag-shaped housing according to claim 8, further comprising: A first extrusion protrusion protrudes inward from the first bottom surface to support the first end face of the electrode assembly; as well as A second extrusion protrusion protrudes inward from the second bottom surface to support the second end face of the electrode assembly.

12. A secondary battery, comprising: Electrode assembly; as well as A bag-shaped housing that houses the electrode assembly. The bag-shaped housing includes: A forming portion having a predetermined depth, and including a first forming portion that allows a first end face of the electrode assembly to be received therein and a second forming portion that allows a second end face of the electrode assembly to be received therein; A notch that extends from or is spaced apart from each of the opposite ends of the formed portion; and A storage section that covers the portion of the electrode assembly not contained in the forming section. The storage section includes: A central storage section that covers the first side surface of the electrode assembly between the first forming section and the second forming section; A first storage portion includes a first receiving portion covering a portion of a second side surface of the electrode assembly and a first engaging portion extending from an end of the first receiving portion and bending outward toward the electrode assembly; and The second storage portion includes a second receiving portion covering the remaining portion of the second side surface of the electrode assembly and a second engaging portion extending from the end of the second receiving portion and bending outward toward the electrode assembly. The first joint and the second joint are joined together to make surface contact with each other.

13. The secondary battery according to claim 12, wherein, The first and second joints bend outward toward the second side surface of the electrode assembly in a manner that their surfaces are in contact with each other.

14. A secondary battery module, comprising: At least two secondary batteries are stacked along the direction of the first side surface. The secondary batteries are arranged to be spaced apart from each other at predetermined intervals, and Each secondary battery includes: Electrode assembly; and A bag-shaped housing that houses the electrode assembly. The bag-shaped housing includes: A forming portion having a predetermined depth, and including a first forming portion that allows a first end face of the electrode assembly to be received therein and a second forming portion that allows a second end face of the electrode assembly to be received therein; A notch that extends from or is spaced apart from each of the opposite ends of the formed portion; and A storage section that covers the portion of the electrode assembly not contained in the forming section. The storage section includes: A central storage section that covers the first side surface of the electrode assembly between the first forming section and the second forming section; A first storage portion includes a first receiving portion covering a portion of a second side surface of the electrode assembly and a first engaging portion extending from an end of the first receiving portion and bending outward toward the electrode assembly; and The second storage portion includes a second receiving portion covering the remaining portion of the second side surface of the electrode assembly and a second engaging portion extending from the end of the second receiving portion and bending outward toward the electrode assembly. The first and second storage portions wrap around the electrode assembly from opposite directions on the second side surface, and the first and second joint portions are joined to make surface contact with each other to form a sealing joint that bends outward toward the second side surface of the electrode assembly. When the secondary batteries are stacked in the direction of the first side surface, a predetermined gap is formed between the secondary batteries by the sealing joint that bends outward.

15. The secondary battery module according to claim 14, further comprising: A cooling plate is disposed on a first or second forming portion of each of the secondary batteries.

16. The secondary battery module according to claim 15, wherein, The cooling plate includes: A first cooling plate, which makes surface contact with the first formed portion; and The second cooling plate is in surface contact with the second forming part.

17. The secondary battery module according to claim 14, further comprising: Insulating material, which is disposed in the predetermined interval.

18. A method for manufacturing a secondary battery, the method comprising the steps of: A first forming portion and a second forming portion are formed in a bag-shaped shell such that the first forming portion and the second forming portion are spaced apart from each other; The first end face of the electrode assembly is coupled to the first forming portion; The central storage portion between the first forming portion and the second forming portion is coupled to the first side surface of the electrode assembly to cover the first side surface of the electrode assembly; The second end face of the electrode assembly is coupled to the second forming portion; A second storage portion, including a second receiving portion and extending from the second forming portion, is coupled to a portion of the second side surface of the electrode assembly so as to cover the portion of the second side surface of the electrode assembly through the second receiving portion; and a first storage portion, including a first receiving portion and extending from the first forming portion, is coupled to the remaining portion of the second side surface of the electrode assembly so as to cover the remaining portion of the second side surface of the electrode assembly through the first receiving portion. The first flexible joint at the end of the first receiving portion and the second flexible joint at the end of the second receiving portion are joined together, such that the first flexible joint and the second flexible joint are in surface contact with each other on the second side surface of the electrode assembly; as well as A sealing joint is bent in one direction on the second side surface of the electrode assembly, the sealing joint being formed by the engagement of the first flexible joint and the second flexible joint.

19. The method according to claim 18, wherein, The step of forming the first forming portion and the second forming portion in the bag-shaped housing to space them apart includes: A first notch and a second notch are formed, wherein the first notch extends from each of the opposite ends of the first formed portion in a direction forming the first formed portion, and the second notch extends from each of the opposite ends of the second formed portion in a direction forming the second formed portion.

20. The method according to claim 18, wherein, The step of forming the first forming portion and the second forming portion in the bag-shaped housing to space them apart includes: A first notch and a second notch are formed, wherein the first notch is spaced apart from each of the opposite ends of the first forming portion in one direction in which the first forming portion is formed, and the second notch is spaced apart from each of the opposite ends of the second forming portion in one direction in which the second forming portion is formed.

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