Secondary battery and battery pack including same

Abstract

The present invention relates to a secondary battery and a battery pack including same. The secondary battery according to an aspect of the present invention may comprise: an electrode assembly extending in one direction; a cap covering one side of the electrode assembly in the extension direction; an outer film surrounding the electrode assembly in a circumferential direction; and a fixing member provided on the outer circumferential surface of the electrode assembly and coupled to each of the outer film and the electrode assembly.

Description

Secondary battery and battery pack including the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0154444 filed on November 4, 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 pack, and more specifically, to a secondary battery and a battery pack capable of charging and discharging electrical energy.

[0005] Although secondary batteries have been applied in small-scale fields such as mobile devices and laptop computers, research directions have recently 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). Battery packs can be formed by packaging battery cells made of these secondary batteries.

[0006] Generally, a secondary battery consists of an electrode assembly in which electrodes and a separator are laminated to charge and discharge electrical energy, a case housing the electrode assembly, and conductive electrode leads for conducting electricity to the outside. In this case, the secondary battery can be classified into a cylindrical secondary battery, a pouch-type secondary battery, or a prismatic secondary battery depending on the shape of the case.

[0007] Meanwhile, secondary batteries and battery packs can be subjected to external shocks or vibrations during use. For example, battery packs loaded into electric vehicles to provide power are highly likely to be subjected to strong shocks or periodic vibrations while driving. Such shocks or vibrations can deform the electrode assembly or cause it to deviate from its rated position within the case. Accordingly, there is an urgent need for the development of secondary batteries with improved structural stability and battery packs containing them.

[0008] The present invention has been devised to solve the above problems, and the objective of the present invention is to provide a secondary battery with improved structural stability and a battery pack including the same.

[0009] 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.

[0010] 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 side of the extension direction of the electrode assembly; an outer film wrapping the electrode assembly in a circumferential direction; and a fixing member provided on the outer circumferential surface of the electrode assembly and coupled to the outer film and the electrode assembly, respectively.

[0011] At this time, the outer circumference surface includes a first surface facing the outside of the electrode assembly, and the fixing member may include a first fixing member provided on the first surface.

[0012] At this time, the electrode assembly includes a plurality of stacked electrodes and a separator, and the first surface may be formed parallel to the stacking direction of the plurality of electrodes and the separator.

[0013] At this time, the first surface can face a direction perpendicular to the stacking direction.

[0014] At this time, the stacking direction may be perpendicular to the extension direction of the electrode assembly.

[0015] At this time, the outer circumference surface includes a second surface facing the first surface, and the fixing member may include a second fixing member provided on the second surface.

[0016] At this time, the outer perimeter surface includes a third surface perpendicular to the first surface, and the fixing member may include a third fixing member provided on the third surface.

[0017] At this time, the outer circumference surface includes a fourth surface facing the third surface, and the fixing member may include a fourth fixing member provided on the fourth surface.

[0018] At this time, the fixed member may be extended parallel to the extension direction of the electrode assembly.

[0019] At this time, the above-mentioned fixing member may have a predetermined adhesive force.

[0020] At this time, one side of the fixing member is attached to the outer circumference surface of the electrode assembly, and the other side of the fixing member can be attached to the outer film.

[0021] At this time, the fixed member may have a film or sheet shape.

[0022] At this time, the fixing member is composed of a plurality of members, and the plurality of fixing members can be arranged along the circumference of the electrode assembly.

[0023] According to another aspect of the present invention, a secondary battery is provided, comprising: an electrode assembly extending in one direction; a fixing member surrounding the electrode assembly in a circumferential direction; a cap covering one side of the electrode assembly in the extension direction; and an outer film surrounding the fixing member and the electrode assembly, wherein the fixing member is coupled to the electrode assembly and the outer film, respectively.

[0024] At this time, the fixed member may have a ring shape.

[0025] At this time, the outer film can wrap the fixing member and the electrode assembly in the circumferential direction.

[0026] At this time, the fixing member is composed of a plurality of members, and the plurality of fixing members may be arranged along the extension direction of the electrode assembly.

[0027] At this time, the fixed member may be provided with a flow portion through which the electrolyte can pass.

[0028] At this time, the above-mentioned fluid portion may be extended parallel to the extension direction of the electrode assembly.

[0029] At this time, the above-mentioned fluid portion may extend from one end to the other end of the above-mentioned fixed member based on the extension direction of the above-mentioned electrode assembly.

[0030] At this time, the above-mentioned fluid portion may be open on both sides with respect to the extension direction of the electrode assembly.

[0031] At this time, the above-mentioned movable part may have a slit shape in which a part of the above-mentioned fixed member is cut.

[0032] At this time, the fixed member may have a predetermined thickness in the outer direction of the electrode assembly, and the movable part may be formed as a groove having a depth shallower than the thickness of the fixed member.

[0033] At this time, the above-mentioned fluid portions are composed of a plurality of units, and the plurality of fluid portions may be arranged in the circumferential direction of the electrode assembly.

[0034] At this time, the fixed members are composed of a plurality of fixed members, and the plurality of fixed members are arranged along the extension direction of the electrode assembly, and the movable part of any one of the plurality of fixed members may be arranged parallel to the movable part of an adjacent fixed member in the extension direction.

[0035] At this time, the fixed members are composed of a plurality of fixed members, and the plurality of fixed members are arranged along the extension direction of the electrode assembly, and the movable part of any one of the plurality of fixed members may be arranged offset from the movable part of an adjacent fixed member in the extension direction.

[0036] According to another aspect of the present invention, a battery pack 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 side of the extension direction of the electrode assembly; an outer film wrapping the electrode assembly in a circumferential direction; and a fixing member provided on the outer circumferential surface of the electrode assembly and coupled to the outer film and the electrode assembly, respectively.

[0037] According to another aspect of the present invention, a battery pack 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 fixing member surrounding the electrode assembly in a circumferential direction; a cap covering one side of the electrode assembly in the extension direction; and an outer film surrounding the fixing member and the electrode assembly, wherein the fixing member is coupled to the electrode assembly and the outer film, respectively.

[0038] According to one aspect of the present invention, a fixing member is provided on the outer periphery of an electrode assembly, which is respectively coupled to the electrode assembly and the outer film, so that the relative positions of the electrode assembly and the outer film can be stably fixed. Accordingly, the structural stability of the secondary battery and the battery pack including the same can be improved.

[0039] According to one aspect of the present invention, a fixing member is provided that surrounds the electrode assembly and is coupled to the electrode assembly and the outer film, respectively, so that the laminated structure of the electrode assembly and the relative positions of the electrode assembly and the outer film can be stably fixed. Accordingly, the structural stability of the secondary battery and the battery pack including the same can be improved.

[0040] 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.

[0041] FIG. 1 is a perspective view of a battery pack according to a first embodiment of the present invention viewed from above. In this case, the packaging is indicated by a dotted line, and the components visible therefrom are indicated by a solid line.

[0042] FIG. 2 is a perspective view of a secondary battery according to a first embodiment of the present invention, viewed from above.

[0043] FIG. 3 is an exploded perspective view of a secondary battery according to a first embodiment of the present invention.

[0044] Figure 4 is a cross-sectional view according to II of Figure 2.

[0045] FIG. 5 is a cross-sectional view along II-II of FIG. 2.

[0046] FIG. 6 is an exploded perspective view of a secondary battery according to a second embodiment of the present invention.

[0047] FIG. 7 is a plan view of an electrode assembly and a fixing member of a secondary battery according to a second embodiment of the present invention.

[0048] FIG. 8 is a cross-sectional view of a secondary battery according to a second embodiment of the present invention, cut along line II-II of FIG. 2.

[0049] Figure 9 is an enlarged view of part A of Figure 8.

[0050] FIG. 10 is a plan view of an electrode assembly and a fixing member of a secondary battery according to a third embodiment of the present invention.

[0051] FIG. 11 is an enlarged view of the portion corresponding to part A of FIG. 9 in a vertical cross-section of a secondary battery according to the fourth embodiment of the present invention.

[0052] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0053] 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.

[0054] 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.

[0055] FIG. 1 is a perspective view of a battery pack according to a first embodiment of the present invention viewed from above. In this case, the packaging is indicated by a dotted line, and the components visible therefrom are indicated by a solid line.

[0056] FIG. 1 discloses a battery pack according to a first embodiment of the present invention. Referring to FIG. 1, the battery pack (1) according to the first embodiment of the present invention may be a battery pack for charging and discharging electrical energy. To this end, the battery pack (1) according to the first embodiment of the present invention may include a secondary battery (3).

[0057] In this embodiment, the secondary batteries (3) may be composed of a plurality of units. The plurality of secondary batteries (3) may be arranged in a predetermined manner to form an assembly. For example, as illustrated, the plurality of secondary batteries (3) may be arranged in a row. The arrangement method of the secondary batteries (3) may be appropriately modified as needed.

[0058] A battery pack (1) according to the first embodiment of the present invention may include a packaging (2). The packaging (2) may be configured to accommodate a plurality of secondary batteries (3) and protect them from external shock or contamination.

[0059] To this end, the packaging (2) may be provided as a structure or assembly in the shape of a housing having a predetermined space inside. As an example, the packaging (2) may have a structure in which several plates are combined in a box shape. However, the shape or structure of the packaging (2) is not particularly limited as long as it can accommodate the secondary battery (2).

[0060] Although not specifically described, the packaging (2) may be equipped with components to perform a predetermined function. For example, the packaging (2) may be equipped with a bus bar that conducts current with the internal secondary battery (3), a vent component for communicating the inside and outside of the packaging (2), etc., but is not limited thereto.

[0061] Hereinafter, a secondary battery according to a first embodiment of the present invention will be described. FIG. 2 is a perspective view of a secondary battery according to a first embodiment of the present invention viewed from above. FIG. 3 is an exploded perspective view of a secondary battery according to a first 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.

[0062] Referring to FIGS. 2 to 5, a secondary battery (3) according to the first embodiment of the present invention may include an electrode assembly (10). The electrode assembly (10) may be a component that performs a charging and discharging function. To this end, the electrode assembly (10) may have a structure in which a plurality of electrodes and a separator are stacked.

[0063] At this time, the electrodes may be classified into positive and negative electrodes according to their polarity. The electrodes and separators may be provided in the form of a film or a sheet. Depending on the structure in which the electrodes and separators are stacked, the electrode assembly (10) may be provided in a stacked type, a stacked and folded type, or a cylindrical type. The structure or shape of the electrode assembly (10) is not particularly limited. In this embodiment, the electrode assembly (10) is described on the premise that the electrodes and separators are stacked in the vertical direction (Z-axis direction).

[0064] Referring to FIGS. 3 to 5, the electrode assembly (10) according to the first embodiment of the present invention may be extended in a front-rear direction (X-axis direction). Hereinafter, the direction is referred to as the length direction (or extension direction) of the electrode assembly (10). The outer surface of the electrode assembly (10) may include an outer circumferential surface (12). The outer circumferential surface (12) may be an outer surface provided along the circumference of the electrode assembly (10). At this time, the circumferential direction of the electrode assembly (10) may be a direction that wraps around an axis (X-axis) parallel to the extension direction of the electrode assembly (10).

[0065] In this embodiment, the outer perimeter surface (12) may be a surface facing outward. As will be described specifically later, a fixing member (30) may be provided on the outer perimeter surface (12). The outer perimeter surface (12) may include a first surface (13). The first surface (13) may be a side surface formed parallel to the stacking direction (Z-axis direction). The first surface (13) may be a surface facing in a direction perpendicular to the extension direction (X-axis direction) and the stacking direction (Z-axis direction) of the electrode assembly (10) (Y-axis direction). The first surface (13) may have a predetermined width and length in the extension direction (X-axis direction) and the stacking direction (Z-axis direction).

[0066] In this embodiment, the outer perimeter surface (12) may include a second surface (14). The second surface (14) may be a surface facing the first surface (13). The second surface (14) may also be formed parallel to the stacking direction (Z-axis direction). The second surface (14) may be a surface facing a direction (Y-axis direction) perpendicular to the extension direction (X-axis direction) and the stacking direction (Z-axis direction) of the electrode assembly (10). The second surface (14) may have a predetermined length and width in the extension direction (X-axis direction) and the stacking direction (Z-axis direction).

[0067] In this embodiment, the outer perimeter surface (12) may include a third surface (15). The third surface (15) may be a surface perpendicular to the first surface (13). Alternatively, the third surface (15) may be perpendicular to the second surface (14). The third surface (15) may be located between the first surface (13) and the second surface (14). In this case, the third surface (15) may be a surface extending parallel to the electrode and / or separator. The third surface (15) may be a surface facing the stacking direction (Z-axis direction). The third surface (15) may have a predetermined length and width in the extension direction (X-axis direction) and in the direction in which the first surface (13) and the second surface (14) are spaced apart (Y-axis direction).

[0068] In this embodiment, the outer perimeter surface (12) may include a fourth surface (16). The fourth surface (16) may be a surface facing the third surface (15). The fourth surface (16) may also be located between the first surface (13) and the second surface (14). The fourth surface (16) may be a surface extending parallel to the electrode and / or separator. The fourth surface (16) may be a surface facing the stacking direction (Z-axis direction). The fourth surface (16) may have a predetermined length and width in the extension direction (X-axis direction) and in the direction in which the first surface (13) and the second surface (14) are spaced apart (Y-axis direction).

[0069] Meanwhile, referring again to FIGS. 3 and 4, the electrode assembly (10) of the secondary battery (3) according to the first embodiment of the present invention may be provided with an electrode tab (11). The electrode tab (11) may be configured to conduct current to the outside of the electrode. To this end, the electrode tab (11) may extend from the electrode. At this time, the electrode tab (11) may extend from the electrode assembly (10) in the front-rear direction (X-axis direction). This may be for coupling with a cap (40) located at the front and rear of the electrode assembly (10).

[0070] Referring to FIGS. 1 to 5, a secondary battery (3) according to a first 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 a cap (40) described later. In this embodiment, the outer film (20) may have a certain flexibility so that it can be bent by an external force. As an example, the outer film (20) may have the same structure as the outer material constituting a conventional pouch-type case. However, the type or structure of the outer film (20) is not particularly limited as long as it can seal the electrode assembly (10).

[0071] In this embodiment, the outer film (20) can wrap around the electrode assembly (10) in a circumferential direction. The outer film (20) can cover the entire outer circumferential surface (12) of the electrode assembly (10). As the outer film (20) wraps around the electrode assembly (10), one edge portion and another edge portion of the outer film (20) may come into contact. To enhance sealing, the one edge portion and the other edge portion may be welded together. Alternatively, the one edge portion and the other edge portion may be fused by heat or pressure. The joining structure of the edge portions is not particularly limited.

[0072] Referring to FIGS. 3 to 5, a secondary battery (3) according to a first embodiment of the present invention may include a fixing member (30). The fixing member (30) may be configured to be coupled to an outer film (20) and an electrode assembly (10), respectively, to fix the relative positions of the outer film (20) and the electrode assembly (10). As a result, the rated position of the electrode assembly (10) can be maintained.

[0073] In this embodiment, the fixing member (30) may be provided on the outer circumferential surface (12) of the electrode assembly (10). Alternatively, the fixing member (30) may be positioned between the outer surface of the electrode assembly (10) and the inner surface of the outer film (20). At this time, the fixing member (30) may be composed of multiple members and provided in various regions of the outer circumferential surface (12). Through this, various parts of the electrode assembly (10) may be fixed by the fixing member (30).

[0074] In this embodiment, the fixing member (30) may have a predetermined adhesive force. The fixing member (30) may be provided in the form of a thin film or sheet. That is, the fixing member (30) may be composed of double-sided tape. One side of the fixing member (30) may be attached to the outer perimeter surface (12), and the other side may be attached to the inner wall of the outer film (20). As a result, the fixing member (30) can fix the outer film (20) and the electrode assembly (10) without potentially affecting the energy density of the secondary battery (3).

[0075] Meanwhile, referring to FIGS. 3 to 5, in this embodiment, a plurality of fixing members (30) may be arranged in the circumferential direction of the electrode assembly (10) on the outer circumferential surface (12). This arrangement may be possible due to the structural characteristics of the secondary battery (3). More specifically, in the secondary battery (3), an outer film (20) wraps around the electrode assembly (10) in the circumferential direction. Therefore, since the inner surface of the outer film (20) is provided without seams on the circumferential side of the electrode assembly (10), the fixing members (30) may be positioned in any area of ​​the outer circumferential surface (12) and attached to the inner wall of the outer film (20). Through this, the secondary battery (3) can have very high structural stability.

[0076] In contrast, in conventional pouch-type secondary batteries, it is difficult to provide a fixing member on the outer circumference surface of the electrode assembly facing the edge. This is because, in conventional secondary batteries, a pair of cup portions constituting a pouch-type case are arranged to face each other, and then sealing or welding is performed along the edge portion. Since this edge portion has a seam created by sealing or welding, it is bent or warped. As a result, there is an area in the conventional pouch-type secondary battery where a fixing member cannot be provided, so the structural stability is lower compared to the present secondary battery (3).

[0077] In this embodiment, a plurality of fixing members (30) may include a first fixing member (33). The first fixing member (33) may be provided on the first surface (13) of the electrode assembly (10). The first fixing member (33) may be coupled to the first surface (13) and the outer film (20), respectively. The first fixing member (33) may extend in the extension direction (X-axis direction) of the electrode assembly (10) to fix as wide an area as possible of the first surface (13). At this time, since the first fixing member (33) may be attached across multiple electrodes and separators stacked on the first surface (13), it may also perform the function of fixing the stacked structure of the electrode assembly (10).

[0078] Meanwhile, in this embodiment, a plurality of fixing members (30) may include a second fixing member (34). The second fixing member (34) may be provided on the second surface (14) of the electrode assembly (10). The second fixing member (34) may be coupled to the second surface (14) and the outer film (20), respectively. The second fixing member (34) extends in the extension direction (X-axis direction) of the electrode assembly (10) to fix as wide an area as possible of the second surface (14). At this time, since the second fixing member (34) may be attached across multiple electrodes and separators stacked on the second surface (14), it may also perform the function of fixing the stacked structure of the electrode assembly (10).

[0079] In this embodiment, a plurality of fixing members (30) may include a third fixing member (35). The third fixing member (35) may be provided on the third surface (15) of the electrode assembly (10). The third fixing member (35) may be coupled to the third surface (15) and the outer film (20), respectively. The third fixing member (35) may extend in the extension direction (X-axis direction) of the electrode assembly (10) to fix as wide an area as possible of the third surface (15).

[0080] Additionally, in this embodiment, a plurality of fixing members (30) may include a fourth fixing member (36). The fourth fixing member (36) may be provided on the fourth surface (16) of the electrode assembly (10). The fourth fixing member (36) may be coupled to the fourth surface (16) and the outer film (20), respectively. The fourth fixing member (36) extends in the extension direction (X-axis direction) of the electrode assembly (10) to fix as wide an area as possible of the fourth surface (16).

[0081] Meanwhile, in this embodiment, a plurality of fixing members (30) are described as being distributed and arranged on the outer circumference surface (12), including first to fourth fixing members (33 to 36). However, if necessary, the plurality of fixing members (30) may include only some of the first to fourth fixing members (33 to 36), or may include additional fixing members (30). The number or arrangement of the fixing members (30) can be appropriately set considering the size or shape of the electrode assembly (10).

[0082] Referring to FIGS. 2 to 4, a secondary battery (3) according to the first embodiment of the present invention may include a cap (40). The cap (40) may be configured to seal the electrode assembly (10) together with an outer film (20). To this end, the cap (40) may cover one side of the electrode assembly (10) in the extension direction (X-axis direction).

[0083] At this time, the caps (40) are configured as a pair and can cover both sides of the electrode assembly (10). Below, the description focuses on the cap (40) located at the front (positive direction of the X-axis) of the electrode assembly (10). The cap (40) located at the rear (negative direction of the X-axis) of the electrode assembly (10) can also be configured in the same way as the cap (40) described below. Of course, the pair of caps (40) may have different structures or shapes.

[0084] Referring to FIGS. 2 to 5, in this embodiment, the cap (40) may include a cover portion (41). The cover portion (41) may be configured to cover and protect the front portion of the electrode assembly (10). To this end, the cover portion (41) may be made of a metal or plastic material having a certain rigidity, but the material of the cover portion (41) is not limited to the aforementioned.

[0085] In this embodiment, the cover portion (41) may include a cover portion (42). The cover portion (42) may be a portion that covers the front surface of the electrode assembly (10). The cover portion (42) may have a square plate shape having a predetermined thickness. The shape or structure of the cover portion (42) may be appropriately modified according to the shape of the electrode assembly (10).

[0086] In this embodiment, the cover portion (41) may include an extension portion (43). The extension portion (43) may function as a base that is coupled to the exterior film (20). The extension portion (43) may extend from the cover portion (42) toward the electrode assembly (10). The extension portion (43) may extend from the edge of the cover portion (42).

[0087] At this time, the extension portion (43) may have a bulkhead shape provided along the edge of the cover portion (42). The extension portion (43) may be composed of multiple parts and each may extend from the edge (or side) of the cover portion (42). Multiple extension portions (43) may be connected to each other. As a result, when viewed in the front-rear direction (X-axis direction), the multiple extension portions (43) may have a ring shape.

[0088] Meanwhile, the number or shape of the extension portion (43) is not particularly limited as long as it can function as a base that can be combined facing the exterior film (20). For example, the extension portion (43) may be partially provided only in a portion of the edge of the cover portion (42).

[0089] In this embodiment, the cap (40) may include a connecting portion (44). The connecting portion (44) may be a component that combines the cover portion (41) and the exterior film (20). To this end, the connecting portion (44) may be made of an adhesive. Alternatively, the connecting portion (44) may be made of a resin or the like that can combine other components as it solidifies after being melted by heat or pressure.

[0090] The connecting portion (44) may be provided between the outer circumference of the extension portion (43) and the exterior film (20). The connecting portion (44) may be provided along the outer circumference of the extension portion (43). In this embodiment, since the extension portion (43) has a ring shape, the connecting portion (44) may also have a corresponding ring shape. In this case, the ring shape may be a shape viewed in the front-rear direction (X-axis direction). Due to this configuration, the cover portion (41) and the exterior film (20) can be strongly bonded over a wide area. The structure or shape of the connecting portion (44) may be appropriately modified to match the shape of the cover portion (41).

[0091] Meanwhile, in this embodiment, the cap (40) may include a terminal portion (46). The terminal portion (46) may be configured to conduct electricity between the electrode assembly (10) and the outside. To this end, the terminal portion (46) may be made of a conductive material.

[0092] In this embodiment, the terminal portion (46) can be coupled through the cover portion (42). One side of the terminal portion (46) may be exposed to the outside of the electrode assembly (10), and the other side may be exposed toward the electrode assembly (10). The electrode tab (11) of the electrode assembly (10) may be coupled to the other side of the terminal portion (46).

[0093] At this time, the terminal portion (46) may have a rivet shape so as not to detach from the cover portion (42). However, the shape of the terminal portion (46) is not particularly limited as long as it allows the electrode assembly (10) to conduct electricity to the outside. Meanwhile, although not specifically illustrated, a gasket may be provided between the terminal portion (46) and the cover portion (42). The gasket may be made of a polymer such as plastic or rubber. The gasket can prevent the electrolyte from leaking through the gap between the terminal portion (46) and the cover portion (42).

[0094] As previously explained, in the secondary battery (3) according to the first embodiment of the present invention, since the outer film (20) surrounds the electrode assembly (10), a plurality of fixing members (30) can be distributed and arranged on the outer circumferential surface (12) of the electrode assembly (10). Accordingly, the rated position of the electrode assembly (10) can be stably fixed, thereby improving the structural stability of the secondary battery (3) and the battery pack (1) including it. In addition, since the outer film (20) and the electrode assembly (10) are in close contact along the circumferential direction by the fixing members (30), the energy density of the secondary battery (3) can also be improved.

[0095] Hereinafter, a secondary battery according to another embodiment of the present invention is described. At this time, the description focuses on the differences from the secondary battery according to the first embodiment of the present invention described above.

[0096] First, a secondary battery according to the second embodiment of the present invention will be described.

[0097] FIG. 6 is an exploded perspective view of a secondary battery according to a second embodiment of the present invention. FIG. 7 is a plan view of an electrode assembly and a fixing member of a secondary battery according to a second embodiment of the present invention. FIG. 8 is a cross-sectional view of a secondary battery according to a second embodiment of the present invention taken along line II-II of FIG. 2. FIG. 9 is an enlarged view of section A of FIG. 8.

[0098] FIGS. 6 to 9 disclose a secondary battery according to a second embodiment of the present invention. Referring to FIGS. 6 to 9, the secondary battery (103) according to the second embodiment of the present invention may include a fixing member (130). The fixing member (130) may wrap around the outer circumferential surface (12) of the electrode assembly (10) in a circumferential direction.

[0099] In this embodiment, the fixing member (130) may have a ring shape. As a result, the stacked structure of the electrode assembly (10) can be stably fixed. Here, the ring shape may be a shape viewed in the extension direction (X-axis direction) of the electrode assembly (10).

[0100] In this embodiment, the fixing member (130) may be provided between the outer circumferential surface (12) of the electrode assembly (10) and the inner surface (21) of the outer film (20). Alternatively, the outer film (20) may wrap around the electrode assembly (10) and the fixing member (130) surrounding it in a circumferential direction. The fixing member (130) may be coupled to the electrode assembly (10) and the outer film (20), respectively, to fix them together. Through this, the rated position of the electrode assembly (10) can be stably fixed.

[0101] In this embodiment, the fixing member (130) may have a predetermined adhesive force. The fixing member (130) may be provided in the form of a thin film or sheet. That is, the fixing member (130) may be composed of double-sided tape. One side of the fixing member (130) may be attached to the outer perimeter surface (12), and the other side may be attached to the inner surface (21) of the outer film (20). As a result, the fixing member (130) can fix the outer film (20) and the electrode assembly (10) without potentially affecting the energy density of the secondary battery (103).

[0102] As previously explained, in this embodiment, the fixing member (130) may extend in the circumferential direction of the electrode assembly (10) on the outer circumferential surface (12). This configuration may be possible due to the structural characteristics of the secondary battery (103). More specifically, in the secondary battery (103), an outer film (20) wraps around the electrode assembly (10) in the circumferential direction.

[0103] Accordingly, the inner surface (21) of a seamless, smooth outer film (20) is provided on the periphery side of the electrode assembly (10). As a result, the fixing member (30) can be attached entirely to the inner surface (21) of the outer film (20) on the periphery side of the electrode assembly (10). Through this, the secondary battery (103) can have very high structural stability.

[0104] In contrast, in conventional pouch-type secondary batteries, it is difficult to provide a fixing member on the outer circumference surface of the electrode assembly facing the edge. This is because, in conventional secondary batteries, a pair of cup portions constituting a pouch-type case are arranged to face each other, and then sealing or welding is performed along the edge portion. Since this edge portion has a seam created by sealing or welding, it is bent or warped. As a result, there is an area in the conventional pouch-type secondary battery where a fixing member cannot be provided, so the structural stability is lower compared to the present secondary battery (3).

[0105] Meanwhile, in this embodiment, the fixing members (130) may be composed of a plurality of members. The plurality of fixing members (130) may be arranged along the extension direction (X-axis direction) of the electrode assembly (10). As illustrated, in this embodiment, the plurality of fixing members (130) may include first to third fixing members (130a, 130b, and 130c) (hereinafter referred to as 130a to 130c). The first to third fixing members (130a to 130c) may be arranged in the front and rear directions (X-axis direction). The number of fixing members (30) may be appropriately set considering the size of the electrode assembly (10), etc.

[0106] Meanwhile, referring to FIGS. 6 to 9, a fixed member (130) of a secondary battery (103) according to a second embodiment of the present invention may be provided with a flow portion (131). The flow portion (131) may be configured to allow an electrolyte to pass through. As a result, even though the space between the inner surface (21) of the outer film (20) and the outer circumference surface (12) of the electrode assembly (10) is blocked by the fixed member (130), the electrolyte can pass through the fixed member (130) through the flow portion (131).

[0107] In this embodiment, the flow portion (131) may have a slit shape formed by cutting a region of the fixed member (130) in the extension direction (X-axis direction) of the electrode assembly (10). At this time, the flow portion (131) may extend from one end of the fixed member (130) to the other end with respect to the extension direction (X-axis direction). This may be to allow the electrolyte to pass completely through the fixed member (130).

[0108] Meanwhile, in this embodiment, the fluid portion (131) may be composed of a plurality of parts. The plurality of fluid portions (131) may be arranged along the extension direction of the fixed member (130). Alternatively, the plurality of fluid portions (131) may be arranged along the circumferential direction of the electrode assembly (10). As a result, the electrolyte may pass through the fixed member (130) through various parts.

[0109] In this embodiment, the fluid portions (131) of adjacent fixed members (130) among the plurality of fixed members (130) may be arranged offset from each other with respect to the extension direction (X-axis direction). This may be to appropriately disperse the fixing force of the fixed members (130) and the flow of the electrolyte.

[0110] More specifically, the movable portion (131) of the first fixed member (130a) may be arranged offset from the movable portion (131) of the second fixed member (130b) in the extension direction (X-axis direction). The movable portion (31) of the second fixed member (130b) may be arranged offset from the movable portion (131) of the third fixed member (130c) in the extension direction (X-axis direction).

[0111] As previously explained, in the secondary battery (103) according to the second embodiment of the present invention, since the outer film (20) surrounds the electrode assembly (10) in a circumferential direction, the fixing member (130) surrounding the outer circumferential surface (12) of the electrode assembly (10) can be stably coupled to the inner surface (21) and the outer circumferential surface (12) of the outer film (20), respectively.

[0112] Accordingly, since the rated position of the electrode assembly (10) and the stacked structure of the electrode assembly (10) can be stably fixed, the structural stability of the secondary battery (103) and the battery pack (1) including it can be improved. In addition, since the outer film (20) and the electrode assembly (10) can be closely attached along the circumferential direction by the fixing member (130), the energy density of the secondary battery (103) can also be improved.

[0113] Hereinafter, a secondary battery according to the third embodiment of the present invention is described.

[0114] FIG. 10 is a plan view of an electrode assembly and a fixing member of a secondary battery according to a third embodiment of the present invention.

[0115] FIG. 10 discloses an electrode assembly and a fixing member of a secondary battery according to a third embodiment of the present invention. Referring to FIG. 10, the fixing member (230) of the secondary battery (203) according to the third embodiment of the present invention may be composed of a plurality of members and arranged along the length direction (X-axis direction) of the electrode assembly (10). In this embodiment, the movable portions (231) of the fixing members (230) that are adjacent to each other among the plurality of fixing members (210) may be arranged side by side in the length direction (X-axis direction).

[0116] More specifically, the movable portion (231) of the first fixed member (230a) and the movable portion (231) of the second fixed member (230b) may be arranged parallel to each other in the longitudinal direction (X-axis direction). The movable portion (231) of the second fixed member (230b) may be arranged parallel to the movable portion (231) of the third fixed member (230c) in the longitudinal direction (X-axis direction). As a result, the electrolyte contained together with the electrode assembly (10) inside the outer film and the cap can pass more smoothly through the multiple fixed members (230).

[0117] Hereinafter, a secondary battery according to the fourth embodiment of the present invention is described.

[0118] FIG. 11 is an enlarged view of the portion corresponding to part A of FIG. 9 in a vertical cross-section of a secondary battery according to the fourth embodiment of the present invention.

[0119] FIG. 11 discloses a portion of a secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 11, the movable portion (331) of the secondary battery (303) according to the fourth embodiment of the present invention may have a concavely sunken groove shape. At this time, the depth of the groove may be shallower than the thickness of the fixed member (330).

[0120] As a result, the fixed member (330) can maintain a ring shape that wraps around the electrode assembly (10) in a circumferential direction. This is because, at the bottom portion of the movable part (331), a part of the fixed member (330) located on one side of the movable part (331) and another part of the fixed member (330) located on the other side are connected to each other.

[0121] As such, in the secondary battery (303) according to the first embodiment of the present invention, the fixing member (330) maintains a shape connected in the circumferential direction of the electrode assembly (10), so that a tensile force can be applied in the said direction. Through this, in the secondary battery (303) according to the present embodiment, the flow of the electrolyte through the flow portion (331) can be maintained, while the stacked structure of the electrode assembly (10) can be fixed with a stronger force.

[0122] Meanwhile, in this embodiment, the cross-section of the flow section (331) is shown as a rectangle. However, the shape of the flow section (331) is not particularly limited as long as the electrolyte can pass through it. For example, the cross-section of the flow section (331) may have a shape that is a semicircle, a semi-ellipse, or a triangle.

[0123] 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.

[0124] [Explanation of the symbol]

[0125] 1: Battery pack

[0126] 2: Packaging

[0127] 3, 103, 203, 303: Secondary battery

[0128] 10: Electrode assembly

[0129] 20: Exterior film

[0130] 30, 130, 230, 330: Fixing member

[0131] 40: Cap

Claims

1. Electrode assembly extended in one direction; A cap covering one side in the extension direction of the above electrode assembly; An outer film that wraps the electrode assembly in a circumferential direction; and A secondary battery comprising a fixing member provided on the outer circumference of the electrode assembly and respectively coupled to the outer film and the electrode assembly.

2. In Paragraph 1, The above outer perimeter surface is, It includes a first surface facing the outside of the electrode assembly, The above-mentioned fixing member is, A secondary battery comprising a first fixing member provided on the first surface.

3. In Paragraph 2, The above electrode assembly is, It includes a plurality of stacked electrodes and a separator, and The above-mentioned first surface is, A secondary battery formed parallel to the stacking direction of the plurality of electrodes and separators.

4. In Paragraph 3, The above-mentioned first surface is, A secondary battery facing a direction perpendicular to the stacking direction above.

5. In Paragraph 3, A secondary battery in which the stacking direction is perpendicular to the extension direction of the electrode assembly.

6. In Paragraph 2, The above outer perimeter surface is, It includes a second surface facing the first surface, and The above-mentioned fixing member is, A secondary battery comprising a second fixing member provided on the second surface.

7. In Paragraph 2, The above outer perimeter surface is, It includes a third surface perpendicular to the first surface, and The above-mentioned fixing member is, A secondary battery comprising a third fixing member provided on the third surface.

8. In Paragraph 7, The above outer perimeter surface is, It includes a fourth surface facing the third surface, and The above-mentioned fixing member is, A secondary battery comprising a fourth fixing member provided on the fourth surface.

9. In Paragraph 1, The above-mentioned fixed member is a secondary battery that extends parallel to the extension direction of the electrode assembly.

10. In Paragraph 1, The above-mentioned fixing member is a secondary battery having a predetermined adhesive force.

11. In Paragraph 10, One side of the above-mentioned fixed member is attached to the outer circumference of the above-mentioned electrode assembly, and The other side of the above-mentioned fixed member is a secondary battery attached to the above-mentioned exterior film.

12. In Paragraph 10, The above-mentioned fixing member is a secondary battery having a film or sheet shape.

13. In Paragraph 1, The above-mentioned fixing member is composed of a plurality of members, and The above plurality of fixed members are arranged along the circumference of the electrode assembly, forming a secondary battery.

14. Electrode assembly extended in one direction; A fixing member that surrounds the above electrode assembly in a circumferential direction; A cap covering one side in the extension direction of the electrode assembly; and It includes an outer film that wraps the above-mentioned fixed member and the above-mentioned electrode assembly, and The above fixing member is a secondary battery that is respectively coupled to the electrode assembly and the outer film.

15. In Paragraph 14, The above-mentioned fixing member is a secondary battery having a ring shape.

16. In Paragraph 14, The above exterior film is a secondary battery that wraps the above fixing member and the above electrode assembly in the above circumferential direction.

17. In Paragraph 14, The above-mentioned fixing member is composed of a plurality of members, and The above plurality of fixed members are arranged along the extension direction of the electrode assembly, forming a secondary battery.

18. In Paragraph 14, A secondary battery, wherein the fixed member is provided with a flow portion through which an electrolyte can pass.

19. In Paragraph 18, The above-mentioned fluid portion is a secondary battery that extends parallel to the extension direction of the electrode assembly.

20. In Paragraph 19, The above-mentioned fluid portion is a secondary battery that extends from one end of the fixed member to the other end with respect to the extension direction of the electrode assembly.

21. In Paragraph 19, The above-mentioned fluid portion is a secondary battery having both sides open with respect to the extension direction of the electrode assembly.

22. In Paragraph 18, The above-mentioned fluid portion is a secondary battery having a slit shape in which a part of the above-mentioned fixed member is cut.

23. In Paragraph 18, The above fixing member has a predetermined thickness in the outer direction of the electrode assembly, The above-mentioned fluid portion is a secondary battery having a groove having a depth shallower than the thickness of the above-mentioned fixed member.

24. In Paragraph 18, The above fluid section is composed of a plurality of parts, and The plurality of fluid portions above are arranged in the circumferential direction of the electrode assembly, a secondary battery.

25. In Paragraph 18, The above-mentioned fixing member is composed of a plurality of members, and The plurality of fixed members are arranged along the extension direction of the electrode assembly, and A secondary battery in which a movable portion of any one of the plurality of fixed members is arranged parallel to the movable portion of an adjacent fixed member in the extension direction.

26. In Paragraph 18, The above-mentioned fixing member is composed of a plurality of members, and The plurality of fixed members are arranged along the extension direction of the electrode assembly, and A secondary battery in which a movable part of any one of the plurality of fixed members is arranged offset in the extension direction from the movable part of an adjacent fixed member.

27. 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 one side in the extension direction of the above electrode assembly; An outer film that wraps the electrode assembly in a circumferential direction; and A battery pack comprising a fixing member provided on the outer circumference of the electrode assembly and coupled to the outer film and the electrode assembly, respectively.

28. 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 fixing member that surrounds the above electrode assembly in a circumferential direction; A cap covering one side in the extension direction of the electrode assembly; and It includes an outer film that wraps the above-mentioned fixed member and the above-mentioned electrode assembly, and The above fixing member is a battery pack that is respectively coupled to the electrode assembly and the outer film.

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