Secondary battery and battery box comprising same

Abstract

The present invention relates to a secondary battery and a battery box comprising same. According to one aspect of the present invention, the secondary battery comprises: an electrode assembly extending in one direction; a cap covering one portion of the electrode assembly; and an exterior film surrounding the other portion of the electrode assembly. The cap may include: a cover member covering one side along the direction in which the electrode assembly extends; a connection unit provided on one surface of the cover member to couple same to the exterior film; and a heat insulating unit provided on the other surface of the cover member and having a higher melting point than the connection unit.

Description

Secondary battery and battery box including the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0182067 filed on December 09, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a secondary battery and a battery box including the same, and more specifically, to a secondary battery capable of charging and discharging electrical energy and a battery box including the same.

[0005] Although secondary batteries have been applied to small-scale fields such as mobile devices and laptop computers, recently the direction of research has expanded to medium and large-scale fields, and they are widely used in fields requiring high voltage and large capacity, such as Energy Storage Systems (ESS) and Electric Vehicles (EV).

[0006] Meanwhile, as secondary batteries are utilized in various devices, the demand for their stability is increasing. To enhance the stability of secondary batteries, it is necessary to control the direction in which internal gases or flames are discharged during abnormal situations where the battery's temperature or pressure rises. This is because controlling the discharge direction of gases or flames can suppress or control thermal transfer or thermal runaway phenomena.

[0007] The present invention has been devised to solve the above problems, and the objective of the present invention is to provide a secondary battery in which the direction of discharge of internal gas or flame can be controlled, and a battery box including the same.

[0008] The problems of the present invention are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art to which the present invention pertains from the description below.

[0009] According to one aspect of the present invention, a secondary battery is provided, comprising: an electrode assembly extending in one direction; a cap covering one part of the electrode assembly; and an outer film wrapping another part of the electrode assembly, wherein the cap comprises: a cover member covering one side of the extension direction of the electrode assembly; a connecting part provided on one side of the cover member to be coupled with the outer film; and an insulating part provided on the other side of the cover member and having a higher melting point than the connecting part.

[0010] At this time, the melting point of the connecting part is 200 degrees or less, and the melting point of the insulating part may exceed 200 degrees.

[0011] At this time, the connecting portion comprises a polyolefin resin, and the insulating portion may comprise at least one of polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyether etherketone, and polyimide.

[0012] At this time, the cover member may include a plate-shaped cover portion that covers one side of the electrode assembly.

[0013] At this time, the insulation portion may include an insulation portion on the cover portion side provided on an inward surface facing the electrode assembly among the outer surfaces of the cover portion.

[0014] At this time, the cover member includes an extension portion extending from the cover portion toward the electrode assembly, and the connection portion may be provided between the outer surface of the extension portion and the exterior film.

[0015] At this time, the insulation portion may include an insulation portion on the extension side provided on an inner surface facing the outer surface of the extension portion.

[0016] At this time, the extension part includes a first extension part; and a second extension part positioned at a predetermined distance from the first extension part, and the extension part-side insulation part may include a first extension part-side insulation part provided on the inner surface of the first extension part; and a second extension part-side insulation part provided on the inner surface of the second extension part.

[0017] At this time, the extension may include a third extension located between the first and second extensions; and a fourth extension located at a predetermined distance from the third extension.

[0018] At this time, the first to fourth extensions have a ring shape connected to each other, and the insulation portion on the extension side may have a ring shape extended along the inner surface of the first to fourth extensions.

[0019] At this time, the insulation portion may include an end-side insulation portion that blocks the connection portion and the electrode assembly.

[0020] At this time, the insulation portion at the end side may extend in the circumferential direction of the electrode assembly.

[0021] At this time, the insulation portion at the end side may have a ring shape.

[0022] At this time, the insulation portion on the end side extends in the thickness direction of the extension portion and can cover the end of the extension portion.

[0023] At this time, the connecting portion is interposed in the gap between the outer surface of the extension portion and the exterior film, and the end-side insulating portion can cover the gap.

[0024] At this time, the above caps may be provided as a pair and positioned on each side of the extension direction of the electrode assembly.

[0025] At this time, the outer film may include a receiving portion for receiving the electrode assembly; and a sealing portion provided on one side of the receiving portion and provided along the extension direction of the electrode assembly.

[0026] At this time, the insulation part may have a higher melting point than the sealing part.

[0027] At this time, the insulation portion may be formed by injecting a predetermined resin onto the outer surface of the cover member.

[0028] According to another aspect of the present invention, a battery box is provided comprising: a secondary battery; and a packaging that accommodates the secondary battery, wherein the secondary battery comprises: an electrode assembly extending in one direction; a cap covering one part of the electrode assembly; and an outer film wrapping another part of the electrode assembly, wherein the cap comprises: a cover member covering one side of the extension direction of the electrode assembly; a connecting part provided on one side of the cover member and coupled with the outer film; and an insulating part provided on the other side of the cover member and having a higher melting point than the connecting part.

[0029] According to one aspect of the present invention, one side of a cover member is provided with a connecting portion for joining the cover member and an exterior film, and the other side of the cover member is provided with an insulating portion having a higher melting point than the connecting portion, so that the transfer of heat or pressure to the cover member and / or the connecting portion can be suppressed. As a result, in abnormal situations, the direction of discharge of gas or flame can be guided toward the exterior film, thereby improving the stability of the secondary battery.

[0030] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0031] FIG. 1 is a perspective view of a battery box according to one embodiment of the present invention. In this case, the packaging is indicated by a dotted line, and the configuration visible through the packaging is indicated by a solid line.

[0032] FIG. 2 is a perspective view of a secondary battery according to one embodiment of the present invention, viewed from above.

[0033] FIG. 3 is an exploded perspective view of a secondary battery according to one embodiment of the present invention.

[0034] Figure 4 is a cross-sectional view according to II of Figure 2.

[0035] Figure 5 is a cross-sectional view according to II-II of Figure 2.

[0036] Preferred embodiments of the present invention are described in detail so that those skilled in the knowledge can easily implement them. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0037] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0038] In addition, terms or words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0039] FIG. 1 is a perspective view of a battery box according to one embodiment of the present invention. In this case, the packaging is indicated by a dotted line, and the configuration visible through the packaging is indicated by a solid line.

[0040] FIG. 1 discloses a battery box according to an embodiment of the present invention. Referring to FIG. 1, the battery box (1) according to an embodiment of the present invention may include a secondary battery (3). The secondary battery (3) may be configured to charge and discharge electrical energy. At this time, the secondary battery (3) may be a secondary battery according to an embodiment of the present invention described below.

[0041] In this embodiment, to increase the electrical capacity or voltage of the battery box (1), the secondary battery (3) may be composed of a plurality of units. The plurality of secondary batteries (3) may be arranged in a predetermined manner and electrically connected. As illustrated, the plurality of secondary batteries (3) may be stacked in one direction, but the arrangement and electrical connection method of the secondary batteries (3) are not particularly limited.

[0042] A battery box (1) according to one embodiment of the present invention may include a packaging (2). The packaging (2) may be configured to accommodate a secondary battery (3) and protect it from external contamination or impact. To this end, the packaging (2) may have an enclosure shape. However, the structure or shape of the packaging (2) is not particularly limited as long as it can accommodate the secondary battery (3).

[0043] Meanwhile, although not specifically illustrated, parts that perform a predetermined function may be installed in the packaging (2) for the operation or safety of the battery box (1). For example, a connector or bus bar for energizing the secondary battery (3) with the outside may be installed in the packaging (2), and a vent plug for communicating the inside and outside of the packaging (2) may be installed.

[0044] Hereinafter, a secondary battery according to one embodiment of the present invention is described.

[0045] FIG. 2 is a perspective view of a secondary battery according to an embodiment of the present invention viewed from above. FIG. 3 is an exploded perspective view of a secondary battery according to an embodiment of the present invention. FIG. 4 is a cross-sectional view according to II of FIG. 2. FIG. 5 is a cross-sectional view according to II-II of FIG. 2.

[0046] FIGS. 2 to 5 disclose a secondary battery according to an embodiment of the present invention. Referring to FIGS. 2 and FIGS. 3, a secondary battery (3) according to an embodiment of the present invention may include an electrode assembly (10). The electrode assembly (10) may be configured to charge and discharge electrical energy.

[0047] To this end, the electrode assembly (10) may be provided as an assembly in which an anode, a separator, and a cathode are stacked. In this case, the separator may be replaced with an all-solid material, etc. The electrode assembly (10) may be classified into a stack type, a stack & folding type, a cylindrical type, etc., depending on its structure or shape. In this embodiment, the type of electrode assembly (10) is not particularly limited.

[0048] Meanwhile, in this embodiment, the electrode assembly (10) may be extended in the front-rear direction (X-axis direction). Hereinafter, the front-rear direction (X-axis direction) is referred to as the extension direction (or length direction) of the electrode assembly (10), and the direction (or direction surrounding) that wraps around the axis parallel to the length direction (X-axis direction) of the electrode assembly (10) is referred to as the circumference direction of the electrode assembly (10).

[0049] Referring again to FIGS. 2 to 4, a secondary battery (3) according to one embodiment of the present invention may include an electrode tab (11). The electrode tab (11) may be a configuration extending from a positive or negative electrode (hereinafter referred to as an electrode) of an electrode assembly (10). The electrode tab (11) may be a configuration for conducting current to the electrode with the outside.

[0050] In this embodiment, the electrode tabs (11) may be composed of a plurality of electrodes. Each electrode tab (11) may extend from a plurality of electrodes. As illustrated, the electrode tabs (11) may extend forward (positive direction of the X-axis) or backward (negative direction of the X-axis) of the electrode assembly (10). At this time, electrode tabs (11) extending from electrodes having the same polarity may form an assembly. However, the position of the electrode tabs (11) or the number of the assembly is not particularly limited.

[0051] Referring to FIGS. 2 to 5, a secondary battery (3) according to one embodiment of the present invention may include an outer film (20). The outer film (20) may be configured to seal the electrode assembly (10) together with the caps (30, 40, 50, 60) (hereinafter referred to as 30 to 60) described later. The outer film (20) may have a certain flexibility. Accordingly, the outer film (20) may be bent or warped by an external force.

[0052] In this embodiment, the exterior film (20) may be formed into a multilayer structure. For example, the multilayer structure of the exterior film (20) may include a surface protection layer made of a polymer and provided on the outermost layer, a sealant layer made of a polymer and provided on the innermost layer, and a gas barrier layer made of metal interposed between the surface protection layer and the sealant layer.

[0053] Here, the polymer may include polyethylene terephthalate and / or polypropylene, and the metal may include iron (Fe), chromium (Cr), manganese (Mn), nickel (Ni) and / or aluminum. However, the layer structure of the exterior film and the materials forming it may be appropriately modified as needed.

[0054] In this embodiment, the outer film (20) may include a receiving portion (22). The receiving portion (22) may be a part of the outer film (20) that surrounds the electrode assembly (10) in a perimeter direction. As a result, the perimeter side of the electrode assembly (10) can be protected from external impact or contamination.

[0055] In addition, in this embodiment, since the receiving portion (22) is composed of a flexible outer film (20), it can effectively respond to deformation of the electrode assembly (10). For example, the electrode assembly (10) may increase in volume (swelling phenomenon) during the charging and discharging process. In this process, the receiving portion (22) may bend in response to the deformation of the electrode assembly (10).

[0056] In other words, the shape of the receiving portion (22) can be deformed in response to the deformation of the electrode assembly (10). Since such deformation can relieve localized force or pressure between the electrode assembly (10) and the receiving portion (22), damage to the electrode assembly (10) can be prevented.

[0057] In contrast, since the case of a fixed-shape prismatic secondary battery cannot be deformed in response to the deformation of the electrode assembly (10), excessive local force or pressure may occur between the case and the electrode assembly (10). This causes a problem that damages the electrode assembly (10).

[0058] Meanwhile, in this embodiment, the outer film (20) may include a sealing portion (24). The sealing portion (24) may be a portion where one edge portion and another edge portion of the outer film (20) overlap and are sealed. The sealing portion (24) may extend long in the longitudinal direction (X-axis direction) of the electrode assembly (10) from one side of the perimeter of the electrode assembly (10). As a result, the perimeter of the electrode assembly (10) can be sealed, and the electrolyte contained with the electrode assembly (10) can not leak to the outside.

[0059] Such a sealing portion (24) can function as a passage for discharging gas or flame in abnormal situations. For example, when the internal pressure or temperature of the secondary battery (3) rises excessively, the sealing portion (24) may break and discharge gas or flame. In this way, by guiding the discharge of gas or flame in abnormal situations toward the sealing portion (24) of the outer film (20), the stability of the secondary battery (3) can be improved.

[0060] Referring to FIGS. 2 to 5, a secondary battery (3) according to one embodiment of the present invention may include caps (30 to 60). The caps (30 to 60) may be configured to seal the electrode assembly (10) together with an outer film (20). The caps (30 to 60) may be located on one side in the longitudinal direction (X-axis direction) of the electrode assembly (10). The caps (30 to 60) may be combined with the outer film (20). As a result, the electrolyte may not leak to the outside between the caps (30 to 60) and the outer film (20).

[0061] At this time, the caps (30 to 60) may be configured as a pair and provided on each side in the longitudinal direction (X-axis direction) of the electrode assembly (10). The pair of caps (30 to 60) may be configured symmetrically with respect to the electrode assembly (10). However, if necessary, only one cap (30 to 60) may be configured, or the pair of caps (30 to 60) may have different structures or shapes.

[0062] In the following, when describing the caps (30 to 60) of the secondary battery (3) according to one embodiment of the present invention, the description is based on the caps (30 to 60) placed in front of the electrode assembly (10) (positive direction of the X-axis).

[0063] Referring to FIGS. 2 to 5, the cap (30 to 60) of the secondary battery (3) according to one embodiment of the present invention may include a cover member (30). The cover member (30) may be a member that covers the front (positive direction of the X-axis) of the electrode assembly (10).

[0064] At this time, the cover member (30) may be made of a material having a certain rigidity. For example, the cover member (30) may be made of metal or reinforced plastic, etc. Accordingly, the electrode assembly (10) can be protected from external impact or contamination. However, the material of the cover member (30) is not limited to the aforementioned.

[0065] In this embodiment, the cover member (30) may include a cover portion (32). The cover portion (32) may be a rectangular plate that covers the front (positive direction of the X-axis) of the electrode assembly (10). The cover portion (32) may extend in the vertical direction (Z-axis direction) and the horizontal direction (Y-axis direction). The cover portion (32) may have a predetermined thickness in the longitudinal direction (X-axis direction) of the electrode assembly (10). However, the structure or shape of the cover portion (32) is not particularly limited as long as it can cover the front (positive direction of the X-axis) of the electrode assembly (10).

[0066] In this embodiment, the cover member (30) may include an extension (34). The extension (34) may be configured to extend from the cover member (32) toward the electrode assembly (10) side (i.e., the rear (negative direction of the X-axis)).

[0067] In this embodiment, the extension portion (34) may be a part that is combined with the exterior film (20). The extension portion (34) may be connected to the cover portion (32). Alternatively, the extension portion (34) and the cover portion (32) may be provided as a single unit. Of course, if necessary, the extension portion (34) and the cover portion (32) may be provided separately and then combined.

[0068] Referring to FIGS. 3 and 4, in this embodiment, the extension portion (34) may be composed of a plurality of parts. Each of the plurality of extension portions (34) may extend from the edge portion of the cover portion (32).

[0069] In this embodiment, the extension part (34) may include a first and second extension part (34a, 34b). The first extension part (34a) and the second extension part (34b) may be positioned at a predetermined distance apart in the vertical direction (Z-axis direction). The first extension part (34a) and the second extension part (34b) may be parallel to each other.

[0070] More specifically, the first extension (34a) may extend in the left-right direction (Y-axis direction) along the upper edge (positive direction of the Z-axis) of the cover portion (32). The second extension (34b) may extend in the left-right direction (Y-axis direction) along the lower edge (negative direction of the Z-axis) of the cover portion (32). The first and second extensions (34a, 34b) may be provided in the shape of a side wall having a predetermined thickness in the vertical direction (Z-axis direction).

[0071] At this time, the first extension (34a) may include an outer surface (35a), an inner surface (36a), and an end surface (37a). The outer surface (35a) may be a surface facing the outer circumference of the electrode assembly (10). In the illustrated embodiment, the outer surface (35a) may be a surface facing upward (positive direction of the Z-axis). The inner surface (36a) may be a surface facing the outer surface (35a). The inner surface (36a) may be a surface facing downward (negative direction of the Z-axis). The inner surface (36a) may face the second extension (34b). The end surface (37a) may be provided on the end side of the first extension (34a) and may be a surface facing backward (negative direction of the X-axis).

[0072] Meanwhile, the second extension (34b) may also include an outer surface (35b), an inner surface (36b), and an end surface (37b). The outer surface (35b) may be a surface facing the outer circumference of the electrode assembly (10). In the illustrated embodiment, the outer surface (35b) may be a surface facing downward (negative direction of the Z-axis). The inner surface (36b) may be a surface facing the outer surface (35b). The inner surface (36b) may be a surface facing upward (positive direction of the Z-axis). The inner surface (36b) may face the first extension (34a). That is, the inner surface (36a) of the first extension (34a) and the inner surface (36b) of the second extension (34b) may face each other. The end surface (37b) is provided on the end side of the second extension (34b) and may be a surface facing the rear (negative direction of the X-axis).

[0073] Referring to FIGS. 3 and 5, the extension portion (34) may include third and fourth extension portions (34c, 34d). The third extension portion (34c) and the fourth extension portion (34d) may be positioned at a predetermined distance apart in the left-right direction (Y-axis direction). The third and fourth extension portions (34c, 34d) may be positioned between the first and second extension portions (34a, 34b). The third extension portion (34c) and the fourth extension portion (34d) may be parallel to each other.

[0074] More specifically, the third extension (34c) may extend in an up-and-down direction (Z-axis direction) along the right edge (positive direction of the Y-axis) of the cover portion (32). The fourth extension (34d) may extend in an up-and-down direction (Z-axis direction) along the left edge (negative direction of the Y-axis) of the cover portion (32). The third and fourth extensions (34c, 34d) may be provided in a side wall shape having a predetermined thickness in the left-right direction (Y-axis direction).

[0075] At this time, the third extension (34c) may include an outer surface (35c), an inner surface (36c), and an end surface (37c). The outer surface (35c) may be a surface facing the outer circumference of the electrode assembly (10). In the illustrated embodiment, the outer surface (35c) may be a surface facing to the right (positive direction of the Y-axis). The inner surface (36c) may be a surface facing the outer surface (35c). The inner surface (36c) may be a surface facing to the left (negative direction of the Y-axis). The inner surface (36c) may face the fourth extension (34d). The end surface (37c) may be provided on the end side of the third extension (34c) and may be a surface facing to the rear (negative direction of the X-axis).

[0076] Meanwhile, the fourth extension (34d) may also include an outer surface (35d), an inner surface (36d), and an end surface (37d). The outer surface (35d) may be a surface facing the outer circumference of the electrode assembly (10). In the illustrated embodiment, the outer surface (35d) may be a surface facing left (negative direction of the Y-axis). The inner surface (36d) may be a surface facing the outer surface (35d). The inner surface (36d) may be a surface facing right (positive direction of the Y-axis). The inner surface (36d) may face the third extension (34c). That is, the inner surface (36c) of the third extension (34c) and the inner surface (36d) of the fourth extension (34d) may face each other. The end surface (37d) is provided on the end side of the fourth extension (34d) and may be a surface facing the rear (negative direction of the X-axis).

[0077] At this time, referring to FIGS. 3 to 5, the first to fourth extension portions (34a to 34d) according to one embodiment of the present invention may be connected to each other. The first to fourth extension portions (34a to 34d) may have a square ring shape when viewed in the longitudinal direction (X-axis direction) of the electrode assembly (10). The ring shape may be a ring extended in the circumferential direction of the electrode assembly (10).

[0078] Accordingly, the outer surfaces (35a to 35d) of the first to fourth extension parts (34a to 34d) may form the outer circumferential surface of the extension part (34), and the inner surfaces (36a to 36d) may form the inner circumferential surface of the extension part (34). The outer circumferential surface (35a to 35d) and the inner circumferential surface (35a to 36d) of the extension part (34) may face each other. Also, the first to fourth end surfaces (37a to 37d) may have a square ring shape. The ring shape may be a ring extending in the circumferential direction of the electrode assembly (10).

[0079] In this embodiment, the outer circumferential surfaces (35a to 35d) of the extension part (34) may be wrapped by an outer film (20). The outer film (20) may wrap the outer circumferential surfaces (35a to 35d) in the circumferential direction of the electrode assembly (10). As a result, a certain gap may be formed between the inner surface of the outer film (20) and the outer circumferential surfaces (35a to 35d). As will be described in detail later, a connecting part (50) of a cap (30 to 60) may be interposed in the gap to connect them to each other.

[0080] Referring again to FIGS. 2 to 4, the cap (30 to 60) of the secondary battery (3) according to one embodiment of the present invention may include a terminal (40). The terminal (40) may be configured to conduct electricity to the outside of the electrode assembly (10). The terminal (40) may be provided as a conductive member. An electrode tab (11) may be coupled to one side of the terminal (40).

[0081] In this embodiment, the terminal (40) can be coupled to the cover portion (32) of the cover member (30). As a result, the terminal (40) can be supported by the cover member (30). The terminal (40) can be coupled through the cover portion (32). At this time, the terminal (40) may have a rivet structure. Therefore, the terminal (40) may not be detached from the cover portion (32).

[0082] At this time, in this embodiment, a gasket (not shown) may be provided between the terminal (40) and the cover portion (32) to ensure insulation and prevent leakage of electrolyte. The structure of the terminal (40) is not particularly limited as long as it allows the electrode assembly (10) to be electrically connected to the outside.

[0083] Referring to FIGS. 3 to 5, the cap (30 to 60) of the secondary battery (3) according to one embodiment of the present invention may include a connecting portion (50). The connecting portion (50) may be provided on the outer surface of the cover member (30) and may be configured to combine the outer film (20) and the cover member (30). As a result, the electrolyte may not leak between the outer film (20) and the cover member (30).

[0084] In this embodiment, the connecting portion (50) may be interposed between the outer circumferential surface (35a to 35d) of the extension portion (34) and the inner surface of the outer film (20). The connecting portion (50) may extend in the circumferential direction of the electrode assembly (10) and wrap around the outer circumferential surface (35a to 35d) of the extension portion (34).

[0085] At this time, the connecting portion (50) may have a ring shape that wraps around the extension portion (34) from the outside when viewed in the longitudinal direction of the electrode assembly (10). At this time, the connecting portion (50) may have a predetermined width in the longitudinal direction (X-axis direction) of the electrode assembly (10) so that the bonding force between the outer film (20) and the extension portion (34) can be sufficiently secured. Of course, if necessary, the connecting portion (50) may be provided only in one section in the circumferential direction of the electrode assembly (10).

[0086] Meanwhile, in this embodiment, the connecting part (50) may be composed of an adhesive. Alternatively, the connecting part (50) may be formed by a predetermined resin layer provided on the outer circumference surface (35a to 35d) of the extension part (34) or on the inner wall of the exterior film (20) being melted by heat or pressure and then solidified (hereinafter referred to as the sealing process). The resin layer may be formed by injection molding of resin. At this time, the melting temperature (melting point) of the connecting part (50) may be lower than a reference temperature. Here, the melting temperature of the connecting part (50) may be the temperature at which the connecting part (50) begins to melt, and may be determined by the material of the connecting part (50).

[0087] For example, the reference temperature may be 200 degrees. This is because if the melting temperature of the connecting part (50) is higher than 200 degrees, the required temperature for the sealing process to combine the outer film (20) and the cap (30 to 60) becomes excessively high. To this end, the material constituting the connecting part (50) may include polyolefin-based resins such as polypropylene, polyphthalamide, and polyethylene. However, the type of material constituting the connecting part (50) or the reference temperature may be appropriately changed considering the operating environment of the secondary battery (3).

[0088] A cap (30 to 60) of a secondary battery (3) according to one embodiment of the present invention may include an insulating portion (60). The insulating portion (60) may be formed on the outer surface of a cover member (30) with a predetermined thickness. At this time, the insulating portion (60) may be provided on a different side of the outer surface of the cover member (30) where the connecting portion (50) is not provided. The insulating portion (60) may be formed by injecting a predetermined resin onto the outer surface of the cover member (30). However, the process of forming the insulating portion (60) is not limited to the above.

[0089] In this embodiment, the insulating part (60) may be made of a material with a higher melting temperature than the connecting part (50). The insulating part (60) may be configured to suppress the transmission of temperature or pressure to the cover member (30) or the connecting part (50). This may be for controlling the venting direction of the secondary battery (3).

[0090] More specifically, if heat or pressure is transferred to the cap (30 to 60), the cover member (30) or the connecting part (50) may melt or be damaged, which may cause gas or flame to leak between the cover member (30) or the cover member (30) and the exterior film (20), and the control of the venting direction may fail. However, in this embodiment, since the insulation part (60) protects the cover member (30) or the connecting part (50), the flame or gas can be properly guided to the sealing part (24) of the exterior film (20).

[0091] Meanwhile, in this embodiment, the melting temperature of the insulation part (60) may be higher than the reference temperature. As an example, the reference temperature may be 200 degrees. This is because if the melting temperature of the insulation part (60) is lower than 200 degrees, it may be easily deformed by the flame or heat generated in the electrode assembly (10) in an abnormal situation, and thus may not be able to properly protect the connection part (50) or the cover member (30).

[0092] To this end, the material of the insulating part (60) may include at least one of polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyether etherketone, and polyimide. However, the material of the insulating part (60) or the reference temperature may be changed considering the operating environment of the secondary battery (3).

[0093] Referring again to FIGS. 3 to 5, in this embodiment, the insulation portion (60) may include a cover portion-side insulation portion (62). The cover portion-side insulation portion (62) may be provided on the outer surface of the cover portion (32). At this time, the cover portion-side insulation portion (62) may be provided on the inward surface (33) of the cover portion (32). Here, the inward surface (33) may be a surface facing the electrode assembly (10). As a result, the cover portion (32) can be protected from heat or pressure in abnormal situations.

[0094] In this embodiment, the insulation portion (60) may include an extension-side insulation portion (64). The extension-side insulation portion (64) may extend from the cover-side insulation portion (62). Alternatively, the extension-side insulation portion (64) and the cover-side insulation portion (62) may be connected to each other. The extension-side insulation portion (64) may be configured to cover the extension (34) to protect it from heat or pressure.

[0095] In this embodiment, the extension-side insulation portion (64) may be provided on the inner surface (36a to 36d) of the extension (34). More specifically, the extension-side insulation portion (64) may include a first extension-side insulation portion (64a) provided on the inner surface (36a) of the first extension (34a), a second extension-side insulation portion (64b) provided on the inner surface (36b) of the second extension (34b), a third extension-side insulation portion (64c) provided on the inner surface (36c) of the third extension (34c), and a fourth extension-side insulation portion (64d) provided on the inner surface (36d) of the fourth extension (34d).

[0096] In this embodiment, the insulation portions (64a to 64d) on the first to fourth extension sides may have a predetermined thickness. At this time, the insulation portions (64a to 64d) on the first to fourth extension sides may be connected to each other. The insulation portions (64a to 64d) on the first to fourth extension sides may be provided along the inner circumference surfaces (36a to 36d) of the extension (34).

[0097] At this time, the insulation portions (64a to 64d) on the first to fourth extension side may have a ring shape when viewed in the longitudinal direction (X-axis direction) of the electrode assembly (10). Accordingly, the inner circumferential surface (36a to 36d) of the extension (34) can be protected entirely. Of course, the insulation portions (64) on the extension side may be provided only in a portion of the inner circumferential surface (36a to 36d) of the extension (34).

[0098] Meanwhile, in this embodiment, the insulation portion (60) may include an end-side insulation portion (66). The end-side insulation portion (66) may be a portion that blocks the connection portion (50) and the electrode assembly (10). As a result, the transfer of heat or flame generated in the electrode assembly (10) to the connection portion (50) can be minimized.

[0099] The end-side insulation portion (66) may be configured to cover (or block) the gap between the outer surface of the extension portion (34) and the exterior film (20). One side of the end-side insulation portion (66) may be in contact with the inner wall of the exterior film (20) because the connecting portion (50) is interposed in the gap. The end-side insulation portion (66) may extend along the gap in the circumferential direction of the electrode assembly (10). The end-side insulation portion (66) may have a ring shape when viewed in the extension direction (X-axis direction) of the electrode assembly (10). Thus, the gap can be entirely protected by the end-side insulation portion (66).

[0100] In this embodiment, the end-side insulation portion (66) may have a predetermined width in the thickness direction of the extension portion (34). The end-side insulation portion (66) may also be configured to cover the end surfaces (37a to 37d) of the extension portion (34). The end-side insulation portion (66) may be connected to the end of the extension-side insulation portion (64). As a result, the extension portion (34) may be entirely protected by the insulation portion (60).

[0101] As previously explained, in a secondary battery (3) according to one embodiment of the present invention, a connecting portion (50) that combines the cover member (30) and the outer film (20) is provided between them, and an insulating portion (60) having a higher melting temperature than the connecting portion (50) is provided on the other side of the cover member (30), so that the transfer of flame or heat to the cover member (30) or the connecting portion (50) can be suppressed. Through this, in the secondary battery (3) according to the present embodiment, the discharge of flame or gas can be appropriately guided toward the sealing portion (24) of the outer film (20).

[0102] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0103] [Explanation of the symbol]

[0104] 1: Battery box 2: Packaging

[0105] 3: Secondary battery 10: Electrode assembly

[0106] 11: Electrode tab 20: Exterior film

[0107] 22: Reception Section 24: Ceiling Section

[0108] 30: Cover component 32: Cover part

[0109] 34: Extension part 40: Terminal

[0110] 50: Connection part 60: Insulation part

[0111] 62: Insulation section on the cover side 64: Insulation section on the extension side

[0112] 66: End-side insulation section

Claims

1. Electrode assembly extended in one direction; A cap covering a part of the electrode assembly; and It includes an outer film that wraps another part of the electrode assembly, and The above cap is, A cover member covering one side in the extension direction of the above electrode assembly; A connecting part provided on one side of the above-mentioned cover member and coupled with the above-mentioned exterior film; and A secondary battery comprising an insulating member provided on the other side of the above-mentioned cover member and having a melting point higher than that of the above-mentioned connecting member.

2. In Paragraph 1, The melting point of the above-mentioned connecting part is 200 degrees or less, and A secondary battery in which the melting point of the above-mentioned insulating part exceeds 200 degrees.

3. In Paragraph 1, The above connecting portion comprises a polyolefin resin, and The above-mentioned insulating member comprises at least one of polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyether etherketone, and polyimide, in a secondary battery.

4. In Paragraph 1, The above cover member is, A secondary battery comprising a plate-shaped cover portion covering one side of the electrode assembly.

5. In Paragraph 4, The above insulation part is, A secondary battery comprising a cover portion-side insulating portion provided on an inward surface facing the electrode assembly among the outer surfaces of the cover portion.

6. In Paragraph 4, The above cover member is, It includes an extension portion extending from the above cover portion toward the electrode assembly side, and The above connecting portion is a secondary battery provided between the outer surface of the extension portion and the exterior film.

7. In Paragraph 6, The above insulation part is, A secondary battery comprising an extension-side insulating portion provided on an inner surface facing the outer surface of the extension.

8. In Paragraph 6, The above extension part is, First extension; and It includes a second extension located at a predetermined distance from the first extension, and The insulation portion on the extension side mentioned above is, A first extension-side insulation portion provided on the inner surface of the first extension; and A secondary battery comprising a second extension-side insulating portion provided on the inner surface of the second extension portion.

9. In Paragraph 8, The above extension part is, A third extension located between the first and second extensions; and A secondary battery comprising a fourth extension portion positioned at a predetermined distance from the third extension portion.

10. In Paragraph 9, The first to fourth extensions above have a ring shape connected to each other, The insulation portion on the extension side of the above-mentioned secondary battery has a ring shape extending along the inner surface of the first to fourth extension portions.

11. In Paragraph 6, The above insulation part is, A secondary battery comprising an end-side insulating portion that blocks the connection portion and the electrode assembly.

12. In Paragraph 11, The above end-side insulation portion is, A secondary battery extending in the circumferential direction of the above electrode assembly.

13. In Paragraph 12, The above end-side insulating portion is a secondary battery having a ring shape.

14. In Paragraph 11, The above end-side insulation portion is, A secondary battery extending in the thickness direction of the extension portion and covering the end of the extension portion.

15. In Paragraph 11, The above connecting portion is interposed in the gap between the outer surface of the extension portion and the exterior film, and The above end-side insulating portion is a secondary battery that covers the gap.

16. In Paragraph 1, The above-described cap is provided as a pair and is positioned on each side of the electrode assembly in the extension direction thereof, in a secondary battery.

17. In Paragraph 1, The above exterior film is, A receiving portion for accommodating the above electrode assembly; and A secondary battery comprising a sealing portion provided on one side of the receiving portion and along the extension direction of the electrode assembly.

18. In Paragraph 17, The above insulating portion is a secondary battery having a higher melting point than the above sealing portion.

19. In Paragraph 1, The above-mentioned insulating portion is a secondary battery formed by injecting a predetermined resin onto the outer surface of the above-mentioned cover member.

20. Secondary battery; and It includes a packaging that accommodates the above secondary battery, and The above secondary battery is, Electrode assembly extended in one direction; A cap covering a part of the electrode assembly; and It includes an outer film that wraps another part of the electrode assembly, and The above cap is, A cover member covering one side in the extension direction of the above electrode assembly; A connecting part provided on one side of the above-mentioned cover member and coupled with the above-mentioned exterior film; and A battery box comprising an insulating member provided on the other side of the above-mentioned cover member and having a melting point higher than that of the above-mentioned connecting member.

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