Secondary battery and sealing block for sealing secondary battery

Abstract

The present invention relates to a rechargeable secondary battery and a sealing block for sealing the secondary battery by applying pressure to the secondary battery. The secondary battery according to the present invention comprises: an electrode assembly; a pouch-type exterior material having an inner space in which the electrode assembly is accommodated and an exterior material opening allowing communication between the inner space and the outside; and a cover member inserted into the exterior material opening, wherein a portion, facing the cover member, of the inner surface of the exterior material can include: a sealing surface coupled to the cover member so as to seal the inside of the exterior material; and a separation surface separated from the cover member. The sealing block according to the present invention seals the secondary battery comprising: the electrode assembly; the pouch-type exterior material having an inner space in which the electrode assembly is accommodated; and the cover member inserted into the exterior material opening allowing communication between the inner space and the outside, and comprises a press body, which presses the exterior material and the cover member so as to fuse the exterior material and the cover member to each other and form a sealing part for sealing the inner space.

Description

Secondary batteries and sealing blocks for sealing secondary batteries

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0147085, filed October 30, 2023, and Korean Patent Application No. 10-2024-0149726, filed October 29, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery and a sealing block for sealing the secondary battery, and more particularly, to a secondary battery capable of being charged and discharged and a sealing block for sealing the secondary battery by applying pressure to the secondary battery.

[0005] Unlike primary batteries, which are non-rechargeable, secondary batteries (rechargeable batteries) are rechargeable and dischargeable. Small secondary batteries are used in portable electronic devices such as cell phones, laptops, and camcorders, while medium- or large-sized secondary batteries are widely used as power sources for motors in hybrid vehicles and other vehicles.

[0006] These secondary batteries can be classified into various types depending on the type of outer packaging material that accommodates the electrode assembly. For example, the secondary batteries can be classified into square secondary batteries in which the electrode assembly is accommodated inside a square metal can, cylindrical secondary batteries in which the electrode assembly is accommodated inside a cylindrical metal can, and pouch-type secondary batteries in which the electrode assembly is accommodated inside a pouch made of a laminate sheet.

[0007] Meanwhile, a pouch-type secondary battery can be manufactured by accommodating an electrode assembly in a cup portion within a pouch and then sealing the pouch. However, the molding depth of the cup portion is limited depending on the material properties of the pouch, and there was a problem in that the cup portion could not be molded deep enough to increase the capacity of the secondary battery.

[0008] To solve this problem, a pouch-type secondary battery was manufactured by, in the past, mounting an electrode assembly on a pouch-type outer material, folding or rolling the outer material to form an internal space for accommodating the electrode assembly, inserting a cover member into an open area communicating with the internal space, and then sealing the outer material and the cover member.

[0009] Fig. 1 is a drawing showing an example of a conventional pouch-type secondary battery, and Fig. 1 is a drawing schematically showing a front view of a conventional pouch-type secondary battery. The pouch-type secondary battery (1) includes a pouch-type outer material (3) that accommodates an electrode assembly therein, a cover member (2) inserted into an open area of ​​the outer material (3), and a sealing portion (4) formed by combining the cover member (2) and the outer material (3) and sealing the inner area of ​​the outer material (3).

[0010] The exterior material (3) is composed of a metal substrate layer and a resin layer formed on both surfaces of the metal substrate layer, and the sealing portion (4) can be formed by heat-sealing the inner resin layer formed on the inner surface of the exterior material (3) and the cover member (2). Here, in order to heat-seale the inner resin layer of the exterior material (3) and the cover member (2), a process of pressing the cover member (2) and the exterior material (3) with a high-temperature sealing block must be involved.

[0011] FIG. 2 is a drawing for explaining that a crack occurs in the sealing portion of the pouch-type secondary battery of FIG. 1. FIG. 2 illustrates that a crack is formed in a central region (4a) of one side of the sealing portion (4) according to FIG. 1. In FIG. 2, all regions of the inner surface of the outer material (3) facing the cover member (2) are heat-welded to the cover member (2) to form the sealing portion (4). That is, the sealing portion (4) is formed in all regions where the inner surface of the outer material (3) and the cover member (2) face each other, and the sealing portion (4) is formed as wide as possible.

[0012] In this case, when the sealing portion (4) is formed widely, heat and pressure are not sufficiently transmitted to the side area (4b) of the sealing portion (4), so there is a problem that the sealing performance of the side area (4b) of the sealing portion (4) is reduced.

[0013] In addition, when the sealing portion (4) is heated and pressurized for a long time to improve the sealing performance of the side area (4b) of the sealing portion (4), there was a problem that the center area (4a) of the sealing portion (4) was oversealed and cracks occurred in the center area (4a).

[0014] The present invention has been conceived in recognition of the above problems, and an object of the present invention is to provide a secondary battery that prevents cracks from occurring in a sealing portion and has improved sealing performance in the sealing portion, and a sealing block for sealing such a secondary battery.

[0015] A secondary battery according to the present invention comprises: an electrode assembly; a pouch-shaped outer material having an internal space for accommodating the electrode assembly and an outer material opening for communicating the internal space with the outside; and a cover member inserted into the outer material opening, wherein a portion of the inner surface of the outer material facing the cover member may include a sealing surface that is coupled to the cover member to seal the inside of the outer material; and a separation surface separated from the cover member.

[0016] The above-mentioned exterior material can be formed by rolling or folding the exterior material sheet so that one end and the other end of the exterior material sheet, which includes a metal layer and a resin layer formed on both sides of the metal layer, meet each other.

[0017] One end and the other end of the above outer sheet can be bonded or fused to each other.

[0018] The above sealing surface can be bonded to the cover member by adhesion or fusion.

[0019] The above cover member may have a rectangular block shape.

[0020] On each surface of the cover member facing the inner surface of the outer material, a sealing area where the sealing surface is joined and a separation area facing the separation surface can be formed.

[0021] The sealing region may include a first sealing region in the shape of a straight line extending along an edge of an inner surface of the outer material; a second sealing region extending from one end of the first sealing region toward the inner space; and a third sealing region extending from the other end of the first sealing region toward the inner space.

[0022] The second and third sealing regions may extend along one and the other edge of the cover member, respectively.

[0023] The cover member may have a through hole formed therein into which an electrode lead electrically connected to the electrode assembly is inserted.

[0024] An electrolyte injection port may be formed in the above cover member for injecting an electrolyte into the internal space of the outer material in which the electrode assembly is accommodated.

[0025] A portion of the above cover member may be exposed to the outside of the exterior material.

[0026] The thickness of the first sealing region may be greater than or equal to the thickness of each of the second sealing region and the third sealing region.

[0027] The thickness of the first sealing area may be 3 mm to 10 mm, and the thicknesses of the second sealing area and the third sealing area may each be 3 mm to 7 mm.

[0028] Meanwhile, a sealing block according to the present invention is a sealing block for sealing a secondary battery including an electrode assembly; a pouch-shaped outer material forming an internal space for accommodating the electrode assembly; and a cover member inserted into an opening of the outer material for communicating the internal space with the outside, and may include a press body for pressing the outer material and the cover member so that the outer material and the cover member are fused to each other to form a sealing portion sealing the internal space.

[0029] The press body may include a first body in the shape of a rectangular block extending in a straight line; a second body extending from one end of the first body in a direction perpendicular to the direction in which the first body extends; and a third body extending from the other end of the first body in a direction parallel to the direction in which the second body extends.

[0030] The sealing block according to the present invention may further include a heating member that heats the press body.

[0031] The secondary battery according to the present invention has a sealing surface formed only in a part of the area where the outer material and the cover member face each other, so that the area to which heat and pressure are transmitted is formed relatively narrow, thereby preventing cracks from occurring due to sealing.

[0032] The sealing block according to the present invention includes a press body that presses only the edge area of ​​the portion where the outer material and the cover member of the secondary battery face each other, thereby preventing the area where the outer material and the cover member of the secondary battery face each other from being oversealed.

[0033] Figure 1 is a drawing showing an example of a pouch-type secondary battery.

[0034] Fig. 2 is a drawing for explaining the occurrence of a crack in the sealing portion of the pouch-type secondary battery of Fig. 1.

[0035] Figure 3 is a perspective view of a secondary battery according to the present invention.

[0036] Figure 4 is an exploded perspective view of a secondary battery according to the present invention.

[0037] Figure 5 is a cross-sectional view taken along the AA' direction of Figure 3.

[0038] Figure 6 is a drawing schematically showing the appearance of an outer material and a cover member combined in a secondary battery according to the present invention.

[0039] FIG. 7 is a drawing schematically showing a secondary battery according to the present invention in which a cover member is inserted into the interior of an outer material.

[0040] Figure 8 is a development diagram of an outer material for specifically explaining the sealing surface and the separation surface in a secondary battery according to the present invention.

[0041] Figure 9 is a drawing for explaining the parameters of the upper sealing surface in a secondary battery according to the present invention.

[0042] Figure 10 is a drawing for explaining the parameters of the right sealing surface of a secondary battery according to the present invention.

[0043] Figure 11 is a perspective view showing a cover member of a secondary battery according to the present invention.

[0044] Figure 12 is a perspective view of a sealing block according to the present invention.

[0045] Fig. 13 is a cross-sectional view taken along the BB' direction of Fig. 12.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] Hereinafter, a secondary battery and a sealing block for sealing the secondary battery according to the present invention will be described with reference to the drawings.

[0050]

[0051] secondary battery

[0052] Fig. 3 is a perspective view of a secondary battery (10) according to the present invention, and Fig. 4 is an exploded perspective view of a secondary battery (10) according to the present invention. Fig. 5 is a cross-sectional view taken along the line AA' of Fig. 3.

[0053] Referring to FIGS. 3 to 5, a secondary battery (10) according to the present invention may include an electrode assembly (100); a pouch-shaped outer material (200) having an internal space (220) for accommodating the electrode assembly (100) and an outer material opening (210) for communicating the internal space (220) with the outside; and a cover member (300) inserted into the outer material opening (210). Here, a portion of the cover member (300) inserted into the outer material (200) may be combined with the outer material (200) to form a sealing portion (S1) that seals the internal space (220), and the remaining portion of the cover member (300) inserted into the outer material (200) may form a non-sealing portion (S2) separated from the outer material (200).

[0054] The electrode assembly (100) is a laminate including an anode, a cathode, and a separator, and may have various structures. For example, the electrode assembly may be a stacked electrode assembly in which the anode, the cathode, and the separator are laminated in one direction, or a stack-folded electrode assembly in which the anode, the cathode, and the separator are laminated in one direction and then folded.

[0055] Here, the positive electrode may include a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, and the negative electrode may include a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector. The separator is a membrane of an insulating material interposed between the positive electrode and the negative electrode to block contact between the positive electrode and the negative electrode, and a plurality of pores through which positive ions pass may be formed in the separator.

[0056] The outer material (200) is formed by winding an outer material sheet (200a) in one direction, and an internal space (220) for accommodating an electrode assembly (100) can be formed inside the wound outer material sheet (200a). In addition, both sides of the internal space (220) can be connected to the outside.

[0057] Specifically, the exterior sheet (200a) is a sheet having one end (201a) and another end (202a) spaced apart from the one end (201a) in a predetermined direction, and the exterior sheet (200) can be formed by rolling or folding the exterior sheet (200a) so that the one end (201a) and the other end (202a) meet. The one end (201a) and the other end (202a) of the exterior sheet (200a) can be joined to each other in various ways. For example, the one end (201a) and the other end (202a) can be bonded to each other with an adhesive, or the one end (201a) and the other end (202a) can be heat-fused to each other by receiving heat and pressure.

[0058] One end (201a) of the exterior sheet (200a) can be joined to the inner surface or outer surface of the other end (202a). As illustrated in FIG. 4, the outer surface of one end (201a) of the exterior sheet (200a) can be joined to the inner surface of the other end (202a). Additionally, the inner surface of one end (201a) of the exterior sheet (200a) can also be joined to the inner surface of the other end (202a).

[0059] Meanwhile, the exterior sheet (200a) may be a laminate sheet including a metal layer such as aluminum or stainless steel. At this time, a resin layer may be formed on each of the outer and inner surfaces of the metal layer.

[0060] The metal layer can serve as a substrate that maintains mechanical strength and a barrier layer that prevents the infiltration of moisture and oxygen. In addition to preventing the inflow or leakage of foreign substances such as gas and moisture, the metal layer can be composed of aluminum or an aluminum alloy to enhance the strength of the battery case. Examples of aluminum alloys that can be used include alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105, and these can be used alone or in combination.

[0061] The first resin layer coated on the outer surface of the metal layer must have excellent resistance to the external environment in order to protect the electrode assembly from the outside. Therefore, the first resin layer is required to have excellent tensile strength and corrosion resistance relative to its thickness. For the first resin layer, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyolefin resin such as polyethylene or polypropylene, etc. can be used.

[0062] The second resin layer coated on the inner surface of the metal layer can be combined with a cover member (300) described later to seal the internal space (220), and the second resin layer can be composed of a polyolefin series resin. For example, CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene propylene copolymer, polyethylene and acrylic acid copolymer, and polypropylene and acrylic acid copolymer can be used for the second resin layer.

[0063] Conventionally, a pouch-type secondary battery has been manufactured by forming a cup portion on a pouch film, inserting an electrode assembly into the cup portion, and then sealing the pouch film with the formed cup portion with another pouch film. However, due to the material properties of the pouch film, there was a limit to the forming depth of the cup portion, making it impossible to form the cup portion deeply to increase the capacity of the secondary battery. Furthermore, during the forming process of the cup portion, the thickness of the pouch film was reduced, which caused problems such as cracks to occur in the pouch film.

[0064] On the other hand, since the outer material (200) of the secondary battery (10) according to the present invention is prepared by rolling or folding the outer material sheet (200a), the electrode assembly (100) can be accommodated in the internal space (220) of the outer material (200) without a separate cup portion forming. In this case, since the conventional limitation due to the formation of the cup portion in the outer material is not applied, the capacity of the secondary battery (10) can be easily increased by increasing the size of the internal space (220). In addition, since the outer material (200) prepared by rolling or folding the outer material sheet (200a) does not have a portion where the thickness is reduced, the occurrence of defects such as cracks in the outer material (200) can be prevented.

[0065] For reference, the secondary battery (10) according to the present invention can be formed by placing the electrode assembly (100) on the upper surface of the outer sheet (200a) in an unfolded state, and then rolling or folding the outer sheet (200a). In addition, the secondary battery (10) according to the present invention can be formed by rolling or folding the outer sheet (200a) to form an internal space (220) and an outer opening (210), and then inserting the electrode assembly (100) into the outer opening (210). In both of the above cases, the electrode assembly (100) can be accommodated inside the outer sheet (200) without forming a separate cup portion.

[0066] Meanwhile, referring to FIGS. 3 to 5, the cover member (300) may be a member that is coupled to the outer material (200) and blocks the outer material opening (210). The inner space (220) of the outer material (200) in which the electrode assembly (100) is accommodated may be filled with an electrolyte, and the cover member (300) may seal the inner space (220) to prevent the electrolyte from leaking from the inner space (220). Specifically, the cover member (300) inserted into the outer material opening (210) that connects the inner space (220) and the outside may be coupled to the inner surface (230) of the outer material (200) to seal the inner space (220). Here, the inner surface (230) of the outer material (200) may be the second resin layer described above.

[0067] The length of the portion of the cover member (300) that is inserted into the interior of the exterior material (200) may vary. For example, as illustrated in FIGS. 3 and 5, only a portion of the cover member (300) may be inserted into the interior of the exterior material (200), leaving the remaining portion of the cover member (300) exposed to the exterior of the exterior material (200). Additionally, the entire cover member (300) may be inserted into the interior of the exterior material (200).

[0068] The cover member (300) may be formed of a material that is not easily permeable to moisture in order to seal the internal space (220) of the exterior material (200) by being combined with the inner surface (230) of the exterior material (200). For example, the cover member (300) may be obtained from metal or resin, or may be obtained from a laminate sheet in which a resin layer is formed on both sides of a metal layer.

[0069] Meanwhile, the cover member (300) may have various shapes. For example, the cover member (300) may be composed of a body (300a) and a gasket (300b) and may block the internal space (220) of the outer covering (200). Specifically, a through hole through which a gas lead (120) passes may be formed in the body (300a). The gasket (300b) is a member that surrounds the body (300a) and may prevent electrolyte leakage between the outer covering (200) and the body (300a). In this case, the gasket (300b) may also serve as a medium for a firm bond between the outer covering (200) and the body (300a).

[0070] The gasket (300b) may have various shapes. For example, the gasket (300b) may have a frame shape that surrounds a side surface of the outer surface of the body (300a). Additionally, the gasket (300b) may be formed to surround both the inner and outer surfaces of the body (300a).

[0071] In addition, the cover member (300) may have a rectangular box shape. In this case, the four side surfaces of the cover member (300) inserted into the outer material opening (210) face the inner surface (230) of the outer material (200), and since all four side surfaces of the cover member (300) are formed as flat planes, the four side surfaces of the cover member (300) are firmly combined with the inner surface (230) of the outer material (200), so that the inner space (220) of the outer material (200) can be effectively sealed.

[0072] The cover member (300) can be heat-sealed to the inner surface (230) of the exterior material (200) to seal the inner space (220) of the exterior material (200). Specifically, the cover member (300) and the exterior material (200) can be heat-sealed to each other by being pressed by a sealing block at a high temperature or by receiving heat and pressure simultaneously from the sealing block. Here, the sealing block can pressurize an edge portion among the portions where the four flat sides of the cover member (300) and the exterior material (200) meet to form a sealing portion (S1) in which the exterior material (200) and the cover member (300) are heat-sealed.

[0073] Here, since there are no protruding or dug-out portions in each of the four areas where the sealing block presses the exterior material (200) and the cover member (300), the sealing block can transmit uniform pressure to the body (300a) of the pressurized exterior material (200) and the cover member (300). In this case, the inner surface (230) of the exterior material (200) can be uniformly heat-sealed to the edge portions of each of the four surfaces of the cover member (300) to form four sealing portions (S1).

[0074] Meanwhile, the sealing portion (S1) may be an adhesive layer formed between the exterior material (200) and the cover member (300). Specifically, an adhesive layer using an adhesive tape or a cured adhesive may be formed between the edge area of ​​each of the four surfaces of the cover member (300) and the exterior material (200), and this may become the sealing portion (S1) sealing the internal space (220).

[0075] The cover member (300) may be composed of a body (300a) and a gasket (300b) that surrounds the side of the body (300a), and the sealing portion (S1) may be bonded between the gasket (300b) and the outer material (200).

[0076] Fig. 6 is a drawing schematically showing a state in which an exterior material (200) and a cover member (300) are combined. Fig. 6 shows one surface of a cover member (300) inserted into an exterior material (200), and the portion where one surface of the cover member (300) and the exterior material (200) face each other can be divided into a sealing portion (S1) and a non-sealing portion (S2).

[0077] Here, the non-sealing portion (S2) is a portion that is not pressurized by the sealing block, and the exterior material (200) and the cover member (300) are separated from each other in the non-sealing portion (S2). That is, the portion where the exterior material (200) and the cover member (300) face each other can be composed of a sealing portion (S1) in which the exterior material (200) and the cover member (300) are mutually joined, and a non-sealing portion (S2) in which the exterior material (200) and the cover member (300) are mutually separated.

[0078] Fig. 7 is a drawing schematically showing a cover member (300) being inserted into the interior of an exterior material (200). After the cover member (300) is inserted into the exterior material (200), a portion of one surface of the cover member (300) facing the exterior material (200) may be divided into a sealing area (310) and a separation area (320). The sealing area (310) may be an area that is sealed with the inner surface (230) of the exterior material (200) to seal the internal space (220), and the separation area (320) may be an area that is separated from the inner surface of the exterior material (200) without being combined with it.

[0079] Specifically, the sealing region (310) may be formed on the surface of the gasket (300b) of the cover member (300). The gasket (300b) surrounds the side of the body (300a), and the sealing region (310) may be formed on the outer surface of the gasket (300b). Here, a separation region (320) that is not combined with the inner surface of the outer material (200) but is separated may also be formed on the outer surface of the gasket (300b).

[0080] Meanwhile, the portion of the inner surface (230) of the exterior material (200) that faces one surface of the cover member (300) can be divided into a sealing surface (231) and a separation surface (232). The sealing surface (231) is coupled to the cover member (300) to seal the inner space (220), and the separation surface (232) can be separated without being coupled to the cover member (300). Specifically, the sealing surface (231) can be coupled to the gasket (300b) of the cover member (300). In addition, the separation surface (232) faces the gasket (300b), but can be separated without being coupled to the gasket (300b).

[0081] In addition, when the cover member (300) is inserted into the interior of the outer material (200), the sealing surface (231) and the sealing area (310) may correspond to each other, and the separation surface (232) and the separation area (320) may correspond to each other. That is, on each surface of the cover member (300) facing the inner surface (230) of the outer material, a sealing area (310) to which the sealing surface (231) is coupled and a separation area (320) facing the separation surface (232) may be formed. In this case, the sealing surface (231) may be coupled with the sealing area (310) to form a sealing portion (S1) that seals the inner space (220) of the outer material (200), and the separation surface (232) and the separation area (320) may be separated from each other to form a non-sealing portion (S2).

[0082] The sealing surface (231) can be thermally bonded to the sealing area (310) to seal the internal space (220). Specifically, the cover member (300) and the exterior material (200) can be thermally bonded to each other by being pressed by the sealing block at a high temperature or by receiving heat and pressure simultaneously from the sealing block. At this time, the sealing area (310) of the sealing surface (231) is pressed by the sealing block, and the separation surface (232) and the separation area (320) may not be pressed by the sealing block.

[0083] Here, the sealing surface (231) and the sealing area (310) can be thermally fused to each other to form a sealing portion (S1), and the separation surface (232) and the separation area (320) can be maintained in a separated state to form a non-sealing portion (S2). The sealing area (310) formed on each of the four side surfaces of the cover member (300) can be thermally fused to the sealing surface (231) formed on the exterior material (200) to form four sealing portions (S1), and the separation area (310) formed on each of the four surfaces of the cover member (300) can be separated from the separation surface (232) formed on the exterior material (200) to form four non-sealing portions (S2).

[0084] Meanwhile, in conventional pouch-type secondary batteries, a sealing portion is formed over the entire area where the inner surface of the outer packaging material and the cover member face each other. However, if the sealing portion is formed widely in this way, heat and pressure are not effectively transmitted to the edges of the sealing portion, and there is a problem that the sealing force at the edges of the sealing portion is weak. In addition, in order to improve the sealing force at the edges of the sealing portion, if the entire sealing portion is pressurized for a long time, there is a problem that the sealing portion is damaged, such as when the center of the sealing portion is excessively sealed and cracks occur in the center of the sealing portion.

[0085] In this regard, in the secondary battery (10) according to the present invention, the inner surface (230) of the outer material (200) and the portion facing the cover member (300) are divided into a sealing portion (S1) and a non-sealing portion (S2), so that the sealing portion (S1) is formed relatively narrow, and conventional problems that occur as the sealing portion is formed wide can be solved.

[0086] For reference, the sealing portion (S1) may be an adhesive layer formed between the sealing surface (231) and the sealing area (310). Specifically, an adhesive layer using an adhesive tape or a cured adhesive may be formed between the sealing area (310) formed on each of the four surfaces of the cover member (300) and the sealing surface (231) formed on the exterior material (200), and this may be a sealing portion (S1) that seals the internal space (220) of the exterior material (200).

[0087] Meanwhile, as illustrated in FIGS. 6 and 7, the sealing area (310) that is combined with the sealing surface (231) to form the sealing portion (S1) may include a first sealing area (311) that is formed in a straight line along the edge of the inner surface (230) of the outer material (200). The first sealing area (311) may be combined with the edge portion of the inner surface (230) of the outer material (200) to block the inner space (220) of the outer material (200) from communicating with the outside.

[0088] The sealing area (310) may include a second sealing area (312) extending from one end of the first sealing area (311) toward the inside of the exterior material (200) and a third sealing area (313) extending from the other end of the first sealing area (311) toward the inside of the exterior material (200). At this time, the second and third sealing areas (312, 313) may extend along one and the other edge of the cover member (300), respectively.

[0089] The corner portion of the cover member (300) can be easily separated from the exterior material (200) after a certain period of time due to its shape being bent at a certain angle, even when it is joined to the exterior material (200). However, when the second and third sealing areas (312, 313) are formed along the corners of the cover member (300), the bonding strength of the corner portion of the cover member (300) is improved, and thus the corner portion of the cover member (300) can be prevented from being separated from the exterior material (200) after a certain period of time.

[0090] Fig. 8 is a development view of the exterior material (200) to specifically explain the sealing surface (231) and the separation surface (232). Referring to Fig. 8, the inner surface (230) of the exterior material (200) may be composed of first to fifth inner surfaces (230a, 230b, 230c, 230d, 230e). First to fourth sealing surfaces (231a, 231b, 231c, 231d) may be formed on one end and the other end of the first to fourth inner surfaces (230a, 230b, 230c, 230d), respectively. Additionally, first to fourth separation surfaces (232a, 232b, 232c, 232d) may be formed on one end and the other end of the first to fourth inner surfaces (230a, 230b, 230c, 230d), respectively.

[0091] The outer material (200) may be rolled or folded to form an internal space (220) that accommodates the electrode assembly (100), and an external material opening (210) that connects the internal space (220) to the outside may be formed on both sides of the internal space (220). A cover member (300) may be inserted into the external material opening (210), and the first to fourth internal surfaces (230a, 230b, 230c, 230d) may each face four sides of the inserted cover member (300).

[0092] At this time, the first to fourth sealing surfaces (231a, 231b, 231c, 231d) formed on the first to fourth inner surfaces (230a, 230b, 230c, 230d) respectively can be joined by heat fusion or adhesion with the sealing areas (310) formed on the four side surfaces of the cover member (300) respectively to form four sealing portions (S1). In addition, the first to fourth separation surfaces (232a, 232b, 232c, 232d) formed on the first to fourth inner surfaces (230a, 230b, 230c, 230d) respectively can form four non-sealing portions (S2) together with the separation areas (320) formed on the four side surfaces of the cover member (300) respectively.

[0093] Figure 9 is a drawing for explaining the parameters of the upper sealing surface in a secondary battery according to the present invention. Figure 9 illustrates the first sealing surface (231a) and the first separation surface (232a) described above.

[0094] Here, the width (a1) of the leg portion of the first sealing surface (231a) must be formed thick enough to sufficiently seal the cover member (300) and the outer material (200). However, if the width (a1) of the leg portion of the first sealing surface (231a) is formed excessively thick, it may cause excessive fusion of the cover member (300) and the outer material (200), thereby damaging the secondary battery (10). Therefore, the width (a1) of the leg portion of the first sealing surface (231a) must not be formed excessively thick.

[0095] That is, the width (a1) of the leg portion of the first sealing surface (231a) must have an appropriate length. Specifically, the width (a1) of the leg portion of the first sealing surface (231a) must have a length of 3 mm or more. If the width (a1) of the leg portion of the first sealing surface (231a) is less than 3 mm, the cover member (300) and the exterior material (200) may not be sufficiently sealed. On the other hand, if the width (a1) of the leg portion of the first sealing surface (231a) is 3 mm or more, the cover member (300) and the exterior material (200) may be sufficiently sealed.

[0096] In addition, the width (a1) of the leg portion of the first sealing surface (231a) may have a length of 7 mm or less. If the width (a1) of the leg portion of the first sealing surface (231a) exceeds 7 mm, there is a possibility that excessive fusion of the cover member (300) and the exterior material (200) may occur. If the width (a1) of the leg portion of the first sealing surface (231a) has a length of 7 mm or less, excessive fusion of the cover member (300) and the exterior material (200) can be prevented.

[0097] Meanwhile, the width (a2) of the table portion of the first sealing surface (231a) should be formed thick enough to sufficiently seal the cover member (300) and the outer material (200). However, if the width (a2) of the table portion of the first sealing surface (231a) is formed excessively thick, it may cause excessive fusion of the cover member (300) and the outer material (200), thereby damaging the secondary battery (10). Therefore, the width (a2) of the table portion of the first sealing surface (231a) should not be formed excessively thick.

[0098] That is, the width (a2) of the table portion of the first sealing surface (231a) must have an appropriate length. Specifically, the width (a2) of the table portion of the first sealing surface (231a) must have a length of 3 mm or more. If the width (a2) of the table portion of the first sealing surface (231a) is less than 3 mm, the cover member (300) and the exterior material (200) may not be sufficiently sealed. On the other hand, if the width (a2) of the table portion of the first sealing surface (231a) is 3 mm or more, the cover member (300) and the exterior material (200) may be sufficiently sealed.

[0099] In addition, the width (a2) of the table portion of the first sealing surface (231a) may have a length of 10 mm or less. If the width (a2) of the table portion of the first sealing surface (231a) exceeds 10 mm, there is a possibility that excessive fusion of the cover member (300) and the exterior material (200) may occur. If the width (a2) of the table portion of the first sealing surface (231a) has a length of 10 mm or less, excessive fusion of the cover member (300) and the exterior material (200) can be prevented.

[0100] Fig. 10 is a drawing for explaining the parameters of the right sealing surface of the secondary battery according to the present invention. Fig. 10 illustrates the second sealing surface (231b) and the second separation surface (232b) described above.

[0101] In the case of the second sealing surface (231b), as with the first sealing surface (231a), it is important that the leg portion and the table portion have appropriate thicknesses. The width (b1) of the leg portion of the second sealing surface (231b) may have a length of 3 mm or more and 7 mm or less. In addition, the width (b2) of the table portion of the second sealing surface (231b) may have a length of 3 mm or more and 10 mm or less.

[0102] When the width (b1) of the leg portion and the width (b2) of the table portion of the second sealing surface (231b) are formed as described above, it is possible to sufficiently seal the cover member (300) and the exterior material (200), while preventing excessive fusion of the cover member (300) and the exterior material (200).

[0103] That is, the width (a1) of the leg portion of the first sealing surface (231a) and the width (b1) of the leg portion of the second sealing surface (231b) may both have a length of 3 mm or more and 7 mm or less. In addition, the width (a2) of the table portion of the first sealing surface (231a) and the width (b2) of the table portion of the second sealing surface (231b) may both have a length of 3 mm or more and 10 mm or less.

[0104] At this time, the first sealing area (311) described above may correspond to the table portion of the sealing surface (231a, 231b, 231c, 231d), and the second and third sealing areas (312, 313) may correspond to the table portion of the sealing surface (231a, 231b, 231c, 231d).

[0105] Accordingly, the thickness of the first sealing area (311) corresponds to the width (a2) of the table portion of the first sealing surface (231a) and the width (b2) of the table portion of the second sealing surface (231b), and the thickness of the first sealing area (311) may have a length of 3 mm or more and 10 mm or less. In addition, the thickness of the second and third sealing areas (312, 313) corresponds to the width (a1) of the leg portion of the first sealing surface (231a) and the width (b1) of the leg portion of the second sealing surface (231b), and the thickness of the second and third sealing areas (312, 313) may have a length of 3 mm to 7 mm or less. At this time, the thickness of the first sealing area (311) may be greater than or equal to the thickness of each of the second and third sealing areas (312, 313).

[0106] Fig. 11 is a perspective view showing a cover member (300). Referring to Fig. 11, a sealing region (310b, 310c) and a separation region (320b, 320c) may be formed on each of the upper surface and the right surface of the cover member (300). The sealing region (310b) formed on the upper surface of the cover member (300) is coupled with the second sealing surface (231b) described above, and the separation region (320b) formed on the upper surface of the cover member (300) may be separated from the second separation surface (232b) described above. In addition, the sealing region (310cb) formed on the right surface of the cover member (300) is coupled with the third sealing surface (231c) described above, and the separation region (320c) formed on the right surface of the cover member (300) may be separated from the third separation surface (232c) described above.

[0107] Meanwhile, as illustrated in FIGS. 3 and 4, an electrolyte injection port may be formed in the cover member (300) for injecting an electrolyte into the internal space (220) of the outer material (200) containing the electrode assembly (100). The electrolyte injection port may be a through hole penetrating the cover member (300).

[0108] An electrolyte injection process can be performed to inject electrolyte into the internal space (220) through the electrolyte injection port. For example, a user can place the secondary battery (10) so that the cover member (300) in which the electrolyte injection port is formed faces upward, and then inject the electrolyte into the internal space (220) of the outer material (200) through the electrolyte injection port.

[0109] Additionally, a degassing process can be performed through the electrolyte inlet to discharge gases generated during activation of the secondary battery (10) to the outside. For example, a user can open the electrolyte inlet to induce the discharge of gases in the internal space (220).

[0110] After the electrolyte injection process or degassing process, the electrolyte injection port can be sealed or welded to seal the internal space (220). In addition, it is also possible to install an openable valve in the electrolyte injection port so that the electrolyte injection port can be opened only when necessary.

[0111] Meanwhile, conventional pouch-type secondary batteries have a gas pocket formed by rolling up a portion of the outer material, and the gas pocket is removed from the outer material after capturing the internal gas of the outer material. Therefore, there has been a problem in the past of repeatedly discarding a portion of the outer material. In this regard, the secondary battery (10) according to the present invention includes an electrolyte injection port formed in a cover member (300), and a user can inject electrolyte into the internal space (220) and discharge gas from the internal space (220) to the outside through the electrolyte injection port, thereby solving the conventional problem of repeatedly discarding a portion of the outer material.

[0112] Meanwhile, as illustrated in FIGS. 3 to 5 and 11, a through hole (330) may be formed in the cover member (300) into which an electrode lead (120) electrically connected to the electrode assembly (100) is inserted. The electrode lead (120) is connected to an electrode tab (110) connected to each electrode non-conductive portion of the electrodes stacked in the electrode assembly (100), and a portion of the electrode lead (120) may be exposed to the outside of the secondary battery (10). Here, the through hole (330) may be formed in the body (300a) of the cover member (300), and the through hole (330) may have a shape corresponding to the shape of the electrode lead (120) to be inserted.

[0113] Additionally, a sealing member such as an O-ring may be interposed between the through hole (330) and the electrode lead (120), or a sealant layer made of thermoplastic resin may be formed. In this case, the electrolyte injected into the internal space (220) can be prevented from leaking through the through hole (330).

[0114]

[0115] ceiling block

[0116] The sealing block (500) according to the present invention is a sealing block for sealing the secondary battery (10) described above, and may include a press body (510) that presses the portion where the outer material (200) and the cover member (300) of the secondary battery (10) face each other. Specifically, the press body (510) presses the outer material (200) and the cover member (300), so that the outer material (200) and the cover member (300) can be fused to each other to seal the internal space (220).

[0117] The press body (510) heat-fuses the cover member (300) and the inner surface (230) of the outer material (200), and can pressurize one surface of the cover member (300) and the outer material (200) while the cover member (300) is inserted into the outer material opening (210). In this case, a sealant layer having a shape corresponding to the shape of the pressing surface pressed by the press body (510) can be formed between one surface of the cover member (300) and the inner surface (230) of the outer material (200).

[0118] As a sealant layer is formed between the inner surface (230) of the outer material (200) and the cover member (300), the inner space (220) of the outer material (200) is sealed, thereby preventing leakage of the electrolyte injected into the inner space (220).

[0119] Meanwhile, the press body (510) can pressurize the exterior material (200) and the cover member (300) at high temperatures to thermally fuse them. In addition, when a heating member (520) described later is installed in the press body (510), the press body (510) can simultaneously transfer heat and pressure to the exterior material (200) and the cover member (300) to thermally fuse them.

[0120] Fig. 12 is a perspective view of a sealing block (500) according to the present invention. Fig. 12 illustrates a specific shape of a press body (510) constituting the sealing block (500). Referring to Fig. 12, the press body (510) may include a first body (511) in the shape of a rectangular parallelepiped block extending in a straight line, a second body (512) extending from one end of the first body (511) in a direction perpendicular to the direction in which the first body (511) extends, and a third body (513) extending from the other end of the first body (511) in a direction parallel to the direction in which the second body (512) extends.

[0121] In this way, the press body (510) can form a sealing area (310) having the first to third sealing areas (311, 312, 313) described above in the cover member (300) by having the first to third sealing areas (311, 312, 313) as provided in the first to third bodies (511, 512, 513). That is, the press body (510) can simultaneously form a first sealing area (311) facing the edge portion of the outer material (200) and second and third sealing areas (312, 313) in contact with the corners of the cover member (300) for the cover member (300) inserted into the interior of the outer material (200).

[0122] In this case, the communication between the internal space (220) of the outer material (200) and the outside can be blocked by the first sealing area (311) formed by the press body (510). In addition, the bonding strength of the corner portion of the cover member (300) is improved by the second and third sealing areas (312, 313) formed by the press body (510), so that the corner portion of the cover member (300) can be prevented from being separated from the outer material (200) after a certain period of time.

[0123] Fig. 13 is a cross-sectional view taken along the line BB' of Fig. 12. Referring to Fig. 13, a heating member (520) for heating the press body (510) may be installed inside the press body (510). The heating member (520) heats the press body (510) to maintain the press body (510) at a high temperature, and may be configured in various ways. For example, the heating member (520) may be a heating wire installed adjacent to the pressing surface of the press body (510) through which the press body (510) presses the outer material (200) and the cover member (300).

[0124] When a heating member (520) is installed inside the press body (510), the temperature of the press body (510) can be maintained high while the exterior material (200) and the cover member (300) are pressurized. Therefore, the press body (510) can simultaneously transmit heat and pressure to the exterior material (200) and the cover member (300), so that the exterior material (200) and the cover member (300) can be heat-fused without a pre-heating step of bringing the exterior material (200) and the cover member (300) to a high temperature state before pressurization.

[0125]

[0126] 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.

[0127]

[0128] [Explanation of symbols]

[0129] 10: Secondary battery 100: Electrode assembly

[0130] 110: Electrode tab 120: Electrode lead

[0131] 200: Exterior material 200a: Exterior material sheet

[0132] 201a: One end of the exterior sheet 202a: The other end of the exterior sheet

[0133] 210: Exterior opening 220: Interior space

[0134] 230: Inner surface of exterior material 231: Sealing surface

[0135] 232: Separation surface 300: Cover member

[0136] 310: Sealing area 311: First sealing area

[0137] 312: Second sealing area 313: Third sealing area

[0138] 320: Separation area 330: Penetration hole

[0139] 500: Sealing block 510: Press body

[0140] 511: First body 512: Second body

[0141] 513: Third body 520: Heating element

[0142] S1: Sealed part S2: Non-sealed part

Claims

1. Electrode assembly; A pouch-shaped outer material having an internal space for accommodating the electrode assembly and an outer material opening for communicating the internal space with the outside; and Including a cover member inserted into the above outer material opening, The part of the inner surface of the above exterior material that faces the cover member is, A sealing surface that is combined with the cover member and seals the inside of the outer material; and A secondary battery including a separating surface separated from the above cover member.

2. In claim 1, The above exterior material is, A secondary battery characterized in that the outer sheet is formed by rolling or folding so that one end and the other end of the outer sheet, which includes a metal layer and a resin layer formed on both sides of the metal layer, meet each other.

3. In claim 2, A secondary battery characterized in that one end and the other end of the outer sheet are bonded or fused to each other.

4. In claim 1, A secondary battery characterized in that the sealing surface is bonded to the cover member by adhesion or fusion.

5. In claim 1, A secondary battery characterized in that the above cover member has a rectangular block shape.

6. In claim 5, A secondary battery characterized in that each surface of the cover member facing the inner surface of the outer material has a sealing area where the sealing surface is joined and a separation area facing the separation surface.

7. In claim 6, The above sealing area is, A first sealing area having a linear shape extending along the edge of the inner surface of the outer material; A second sealing region extending from one end of the first sealing region toward the inner space; and A secondary battery characterized by including a third sealing region extending toward the internal space from the other end of the first sealing region.

8. In claim 7, A secondary battery characterized in that the second and third sealing regions extend along one and the other edge of the cover member, respectively.

9. In claim 1, A secondary battery characterized in that the cover member has a through hole formed therein into which an electrode lead electrically connected to the electrode assembly is inserted.

10. In claim 1, A secondary battery characterized in that an electrolyte injection port is formed in the cover member for injecting an electrolyte into the internal space of the outer material in which the electrode assembly is accommodated.

11. In claim 1, A secondary battery characterized in that a part of the cover member is exposed to the outside of the outer material.

12. In claim 8, A secondary battery, characterized in that the thickness of the first sealing region is greater than the thickness of each of the second sealing region and the third sealing region.

13. In claim 8, The thickness of the first sealing area is 3 mm to 10 mm, A secondary battery, characterized in that the thicknesses of the second sealing area and the third sealing area are each 3 mm to 7 mm.

14. A sealing block for sealing a secondary battery, including an electrode assembly; a pouch-shaped outer material forming an internal space for accommodating the electrode assembly; and a cover member inserted into an opening of the outer material connecting the internal space with the outside. A sealing block including a press body that presses the outer material and the cover member so that the outer material and the cover member are fused to each other to form a sealing portion that seals the inner space.

15. In claim 14, The above press body, A first body in the shape of a rectangular block extended in a straight line; A second body extending from one end of the first body in a direction perpendicular to the direction in which the first body extends; and A sealing block characterized in that it includes a third body extending in a direction parallel to the direction in which the second body extends from the other end of the first body.

16. In claim 14, A sealing block further comprising a heating member for heating the press body.

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