Secondary battery and battery box comprising same

Abstract

The present invention relates to a secondary battery and a battery box comprising same. According to an aspect of the present invention, the secondary battery may comprise: an electrode assembly including a plurality of electrodes stacked on each other and extending in one direction; a cap covering one side of the extension direction of the electrode assembly; an exterior film coupled to the cap and surrounding the electrode assembly in the circumferential direction; a bus bar positioned between the cap and the electrode assembly and extending in the stacking direction of the electrode; and an electrode tab collection extending from the electrode assembly and coupled to the bus bar, wherein the electrode tab collection comprises: a first electrode tab extending from the electrode assembly toward a portion of the bus bar; and a second electrode tab including an electrode-side portion extending from the electrode assembly toward the first electrode tab and a bus bar-side portion extending toward the portion of the bus bar.

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. 10-2024-0170627 filed November 26, 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] A secondary battery can be composed of an electrode assembly consisting of multiple electrodes and a case housing it. Depending on the structure of the case, secondary batteries can be classified into cylindrical, pouch-type, or prismatic types. Recently, secondary batteries in which the electrode assembly is sealed with a cap and an outer film are also being developed. Furthermore, as the required electrical capacity and voltage increase, there is an urgent need for the development of secondary batteries with higher energy densities.

[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 with high energy density and a battery box including the same.

[0008] Another objective of the present invention is to provide a secondary battery capable of stably conducting electricity with the outside and a battery box 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 and including a plurality of electrodes stacked together; a cap covering one side of the extension direction of the electrode assembly; an outer film coupled to the cap and surrounding the electrode assembly in a circumferential direction; a bus bar positioned between the cap and the electrode assembly and extending in the stacking direction of the electrodes; and an electrode tab assembly extending from the electrode assembly and coupled to the bus bar, wherein the electrode tab assembly comprises: a first electrode tab extending from the electrode assembly toward a portion of the bus bar; and a second electrode tab including an electrode-side portion extending from the electrode assembly toward the first electrode tab and a bus bar-side portion extending toward the portion of the bus bar.

[0011] At this time, the first and second electrode tabs may be electrode tabs located at the outermost edge based on the stacking direction.

[0012] At this time, the electrode side portion extends toward another part of the busbar, and the one part and the other part of the busbar may be positioned at a predetermined distance apart in the stacking direction.

[0013] At this time, the electrode assembly includes a first electrode, the first electrode tab is connected to the first electrode, and the first electrode may be positioned closer to the other part among the one part and the other part of the busbar.

[0014] At this time, the electrode assembly includes a second electrode, the second electrode tab is connected to the second electrode, and the second electrode may be positioned closer to the first part of the busbar than to the other part.

[0015] At this time, the second electrode tab may include a curved portion having a folded shape that connects the electrode-side portion and the busbar-side portion.

[0016] At this time, the first electrode tab has a flat shape, and the second electrode tab may have a shape in which one part is folded so that the electrode side part and the busbar side part overlap.

[0017] At this time, a terminal that is coupled through the cap and is electrically connected to the bus bar may be further included.

[0018] At this time, the terminal may extend from the bus bar toward the outside of the cap.

[0019] At this time, a gasket provided between the cap and the terminal; and a fixing member for fixing the gasket to the cap may be further included.

[0020] At this time, the gasket may be made of an insulating material.

[0021] At this time, the terminal extends in the aforementioned direction, and the gasket may include a gasket portion that surrounds the terminal in a circumferential direction.

[0022] At this time, the gasket portion may have a hollow shape.

[0023] At this time, the gasket may include a first gasket catch portion provided on one side of the gasket portion and capable of being caught on one surface of the cap.

[0024] At this time, the gasket includes a second gasket catch portion provided on the other side of the gasket portion and capable of engaging with the other surface of the cap, and the one surface and the other surface of the cap may face each other.

[0025] At this time, the above-mentioned fixing member may have a rivet shape.

[0026] At this time, the fixing member may be provided between the gasket and the terminal.

[0027] At this time, the fixed member and the terminal can be welded together.

[0028] At this time, one side of the fixed member may be extended toward the electrode assembly and coupled with the bus bar.

[0029] At this time, the busbar includes an inward surface facing the electrode assembly side, and the first and second electrode tabs can be coupled to the inward surface.

[0030] At this time, the busbar includes an outward-facing surface facing the cap side, and the first and second electrode tabs can be coupled to the outward-facing surface.

[0031] At this time, the electrode tab assembly includes third and fourth electrode tabs coupled to other parts of the busbar from the electrode assembly, and the fourth electrode tab may have a folded shape.

[0032] At this time, the above part of the busbar is the lower part of the busbar, the other part of the busbar is the upper part of the busbar, and the first and second electrode tabs may be located above the third and fourth electrode tabs.

[0033] 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 a plurality of electrodes stacked together and an electrode assembly extending in one direction; a cap covering one side of the extension direction of the electrode assembly; an outer film coupled to the cap and surrounding the electrode assembly in a circumferential direction; a bus bar positioned between the cap and the electrode assembly and extending in the stacking direction of the electrodes; and an electrode tab assembly extending from the electrode assembly and coupled to the bus bar, wherein the electrode tab assembly comprises: a first electrode tab extending from the electrode assembly toward a portion of the bus bar; and a second electrode tab including an electrode-side portion extending from the electrode assembly toward the first electrode tab and a bus bar-side portion extending toward the portion of the bus bar.

[0034] According to one aspect of the present invention, a first electrode tab extends toward a portion of a busbar, and a second electrode tab includes an electrode-side portion extending toward the first electrode tab and a busbar-side portion extending toward a portion of the busbar, so that the electrode tab assembly and the busbar can be in close contact. As a result, the overall volume of the secondary battery can be reduced, and thus the energy density can be improved.

[0035] According to another aspect of the present invention, a busbar is provided between the cap and the electrode assembly to mediate the connection between the terminal and the electrode tab assembly, so that the electrode assembly and an external load or power source can be stably energized.

[0036] 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.

[0037] 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.

[0038] FIG. 2 is a perspective view of a secondary battery according to a first embodiment of the present invention, viewed from above.

[0039] FIG. 3 is a cross-sectional view according to II of FIG. 2. In this case, among the plurality of electrode tabs constituting the electrode tab assembly, only the first and second electrode tabs are shown.

[0040] Figure 4 is an enlarged view of part A of Figure 3.

[0041] FIG. 5 is an enlarged cross-sectional view of a portion corresponding to part A of FIG. 3 in a secondary battery according to a second embodiment of the present invention.

[0042] FIG. 6 is a cross-sectional view of a secondary battery according to the third embodiment of the present invention, cut according to II of FIG. 2.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] FIG. 1 discloses a battery pack according to one embodiment of the present invention. Referring to FIG. 1, the battery pack (1) according to one embodiment of the present invention may be a battery pack for charging and discharging electrical energy.

[0048] A battery pack (1) according to one embodiment of the present invention may include a secondary battery (3). The secondary battery (3) may be any one of the secondary batteries according to the first and second embodiments described below. In this case, the secondary battery (3) may be composed of a plurality of units.

[0049] Meanwhile, a battery pack (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). Accordingly, the secondary battery (3) may be configured to be protected from external shock or contamination.

[0050] In this embodiment, the packaging (2) may be provided as a box-shaped structure. The packaging (2) may be made of metal or plastic having a certain rigidity. The packaging (2) may have a structure in which a plurality of plates are combined.

[0051] However, the shape or structure of the packaging (2) may be modified as needed. For example, at least one part of the packaging (2) may have a curved shape. Additionally, other parts may be additionally provided in the packaging (2). For example, the packaging (2) may be equipped with a bus bar electrically connected to a plurality of secondary batteries (3) and / or a venting part that communicates the inside and outside of the packaging (2).

[0052] Hereinafter, a secondary battery according to the first embodiment of the present invention is described.

[0053] 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 a cross-sectional view according to II of FIG. 2. In this case, among the plurality of electrode tabs constituting the electrode tab assembly, only the first and second electrode tabs are shown. FIG. 4 is an enlarged view of portion A of FIG. 3.

[0054] Referring to FIGS. 2 to 4, a secondary battery (3) according to a first embodiment of the present invention may include an electrode assembly (10). The electrode assembly (10) may be configured to perform the function of charging and discharging electrical energy. To this end, the electrode assembly (10) may be formed by stacking a plurality of electrodes together. At this time, a separator or a solid-state material may be interposed between the plurality of electrodes to perform an insulating function.

[0055] In this embodiment, a plurality of electrodes may be stacked in an up-and-down direction (Z-axis direction). Hereinafter, the direction is referred to as the stacking direction. The electrode assembly (10) may be classified into cylindrical, stacked, or stacked & folding types, etc., depending on its shape or structure. However, in this embodiment, the type of electrode assembly (10) is not particularly limited.

[0056] In this embodiment, the plurality of electrodes may include a first electrode (12) and a second electrode (14). The first electrode (12) may be an electrode located above the second electrode (14) (in the positive direction of the Z-axis). In this case, the first and second electrodes (12, 14) may be electrodes located at the outermost edge with respect to the stacking direction (Z-axis direction).

[0057] More specifically, the first electrode (12) may be the electrode located at the uppermost side (positive direction of the Z-axis) among the plurality of electrodes, and the second electrode (14) may be the electrode located at the lowermost side (negative direction of the Z-axis) among the plurality of electrodes.

[0058] Meanwhile, in this embodiment, the electrode assembly (10) may be extended in the front-rear direction (X-axis direction). Hereinafter, the said direction is referred to as the length direction (or extension direction) of the electrode assembly (10), and the direction surrounding the length direction of the electrode assembly (10) (or wrapping direction) is referred to as the circumference direction of the electrode assembly (10).

[0059] Referring to FIG. 3, a secondary battery (3) according to a first embodiment of the present invention may include an electrode tab assembly (20). The electrode tab assembly (20) may extend from an electrode assembly (10). The electrode tab assembly (20) may extend along the longitudinal direction (X-axis direction) of the electrode assembly (10).

[0060] In this embodiment, the electrode tab assembly (20) may be composed of electrode tabs extending from the electrodes. At this time, each electrode tab may be provided separately. The electrode tab assembly (20) may be composed of a plurality of electrode tabs stacked together in the stacking direction (Z-axis direction).

[0061] In this embodiment, the electrode tab assembly (20) may include first and second electrode tabs (22, 24). The first electrode tab (22) may be an electrode tab extending from the first electrode (12), and the second electrode tab (24) may be an electrode tab extending from the second electrode (14).

[0062] That is, the first electrode tab (22) may be the electrode tab located at the outermost position among the plurality of electrode tabs. The first electrode tab (22) may be the electrode tab located at the uppermost position (positive direction of the Z-axis) among the plurality of electrode tabs, and the second electrode tab (24) may be the electrode tab located at the lowermost position (negative direction of the Z-axis) among the plurality of electrode tabs.

[0063] In this embodiment, the first electrode (12) may be positioned closer to the upper (53) of the bus bar (50) than to the lower (51). The first electrode tab (22) may extend from the first electrode (12) toward the lower (51) of the bus bar (50) described later.

[0064] In this embodiment, the end of the first electrode tab (22) may be coupled to the lower part (51) of the bus bar (50). The first electrode tab (22) may be extended in the stacking direction (Z-axis direction). Here, the lower part (51) of the bus bar (50) may refer to a portion located relatively lower (negative direction of the Z-axis) than the upper part (53) described later.

[0065] At this time, the first electrode tab (22) may have a flat shape. Here, having a flat shape means that even if there are partially curved parts, it has a flat shape when viewed as a whole. This may be to improve the energy density of the secondary battery (3) by positioning the bus bar (50) and the electrode assembly (10) as close as possible.

[0066] Meanwhile, in this embodiment, the second electrode (14) may be positioned closer to the lower part (51) than to the upper part (53) of the bus bar (50). The second electrode tab (24) may include an electrode-side portion (25) that extends from the second electrode (14) toward the upper part (53) of the bus bar (50) (or the first electrode tab (22)). At this time, the electrode-side portion (25) may extend in the stacking direction (Z-axis direction). The electrode-side portion (25) may have a flat shape.

[0067] In this embodiment, the second electrode tab (24) may include a busbar-side portion (26). The busbar-side portion (26) may extend toward the lower part (51) of the busbar (50). At this time, the end of the busbar-side portion (26) may be coupled to the lower part (51) of the busbar (50). The busbar-side portion (26) may have a flat shape. The busbar-side portion (26) and the electrode-side portion (25) may overlap each other in the extension direction (X-axis direction) of the electrode assembly (10).

[0068] In this embodiment, the second electrode tab (24) may include a curved portion (27). The curved portion (27) may be a portion connecting the electrode-side portion (25) and the busbar-side portion (26). In this case, the curved portion (27) may have a curved (or bent) shape so as to connect the electrode-side portion (25) and the busbar-side portion (26).

[0069] In other words, the second electrode tab (24) may have a shape that is folded entirely by the curved portion (27). This may be to improve the energy density of the secondary battery (3) by positioning the bus bar (50) and the electrode assembly (10) as close as possible.

[0070] Meanwhile, in this embodiment, the electrode tab assembly (20) may be interposed between the electrode assembly (10) and the bus bar (50). To this end, the first and second electrode tabs (22, 24) may be coupled to the inward surface (50b) of the bus bar (50). As will be described specifically later, the inward surface (50b) may be a surface facing the electrode assembly (10) among the outer surfaces of the bus bar (50).

[0071] Referring again to FIGS. 2 to 4, the secondary battery (3) according to the first embodiment of the present invention may include a cap (30). The cap (30) may be disposed on one side in the extension direction (X-axis direction) of the electrode assembly (10).

[0072] At this time, the caps (30) are configured as a pair and can be placed on each side in the longitudinal direction (X-axis direction) of the electrode assembly (10). The pair of caps (30) can be formed symmetrically around the electrode assembly (10). Of course, the pair of caps (30) may have different structures or shapes as needed.

[0073] In this embodiment, the cap (30) may include a cover portion (32). The cover portion (32) may cover one side of the electrode assembly (10) in the longitudinal direction (X-axis direction). The cover portion (32) may have a plate shape. As an example, the cover portion (32) may have a square plate shape, but the structure or shape of the cover portion (32) is not limited thereto. The cover portion (32) may be made of metal or plastic having a predetermined rigidity.

[0074] In this embodiment, the cap (30) may include an extension portion (34). The extension portion (34) may be configured to be combined with an outer film (40) described later. The extension portion (34) may extend from the cover portion (32) toward the electrode assembly (10). The extension portion (34) may be connected to the cover portion (32). The extension portion (34) may be made of the same material as the cover portion (32).

[0075] In this embodiment, the extension portion (34) may extend from the edge portion of the cover portion (32). The extension portion (34) may be provided along the edge of the cover portion (32). The extension portion (34) may have a side wall shape. The extension portion (34) may have a ring shape when viewed in the longitudinal direction (X-axis direction) of the electrode assembly (10).

[0076] Meanwhile, in this embodiment, the cap (30) may include a connecting portion (36). The connecting portion (36) may be configured to connect the extension portion (34) and the outer film (40) to each other. As an example, the connecting portion (36) may be configured by melting and hardening an adhesive or resin.

[0077] In this embodiment, the connecting portion (36) may be provided on the outer surface of the extension portion (34). The connecting portion (36) may be provided on the outer circumference surface of the extension portion (34). The connecting portion (36) may have a ring shape when viewed in the longitudinal direction (X-axis direction) of the electrode assembly (10). The connecting portion (36) may be interposed between the extension portion (34) and the outer film (40).

[0078] Meanwhile, as needed, the connecting part (36) may also cover other parts of the cover part (32) and / or extension part (34). For example, the connecting part (36) may cover the front of the cover part (32) or the inner circumference of the extension part (34).

[0079] Referring again to FIGS. 2 and FIGS. 3, a secondary battery (3) according to the first embodiment of the present invention may include an outer film (40). The outer film (40) may be configured to seal the electrode assembly (10) together with the cap (30). The outer film (40) may have a certain flexibility so that it can be bent by an external force.

[0080] In this embodiment, the outer film (40) can wrap around the electrode assembly (10) in a circumferential direction. Both edge portions of the outer film (40) can be combined with a pair of caps (30). Here, the two edge portions of the outer film (40) may be edge portions provided on both sides of the electrode assembly (10) in the extension direction (X-axis direction).

[0081] The cap (30) and the outer film (40) can be joined by means of a connecting portion (36) interposed between the edge portion of the outer film (40) and the extension portion (34) of the cap (30). As a result, the electrode assembly (10) can be isolated from the outside and leakage of the electrolyte can be prevented.

[0082] As previously explained, in this embodiment, the outer film (40) has a certain flexibility and can be deformed according to the volume change of the electrode assembly (10). For example, the electrode assembly (10) can swell as the charging and discharging process proceeds.

[0083] In this process, the outer film (40) can be bent according to the volume change of the electrode assembly (10), and can prevent excessive force or stress from being applied locally to the electrode assembly (10). Accordingly, the stability and durability of the secondary battery (3) can be improved. In contrast, since the shape of the case of a prismatic secondary battery is fixed, there is a problem in that it cannot respond to the volume change of the electrode assembly.

[0084] Referring to FIGS. 2 to 4, a secondary battery (3) according to the first embodiment of the present invention may include a bus bar (50). The bus bar (50) may be a component for improving the structural stability and energy density of the secondary battery (3).

[0085] In this embodiment, the busbar (50) may be provided as a metal section or metal plate having a predetermined thickness. In this embodiment, the busbar (50) may be extended in the stacking direction (Z-axis direction).

[0086] The busbar (50) may be positioned between the cover portion (32) of the cap (30) and the electrode assembly (10). The busbar (50) may include a lower portion (51) and an upper portion (53). The lower portion (51) and the upper portion (53) may be positioned at a predetermined distance apart in the stacking direction (Z-axis direction). The upper portion (53) may be a portion located relatively higher (in the positive direction of the Z-axis) than the lower portion (51).

[0087] Meanwhile, the busbar (50) may include an outward-facing surface (50a) and an inward-facing surface (50b). The outward-facing surface (50a) may be a surface facing forward (positive direction of the X-axis), and the inward-facing surface (50b) may be a surface facing backward (negative direction of the X-axis). The outward-facing surface (50a) may face the cover portion (32) of the cap (30), and the inward-facing surface (50b) may face the electrode assembly (10). In this embodiment, the first and second electrode tabs (22, 24) may be coupled on the inward-facing surface (50b).

[0088] At this time, the length of the busbar (50) may be shorter than the distance between the parallel connecting parts (36). As a result, the busbar (50) may be located inside the extension part (34). The busbar (50) may perform the function of mediating an electrical connection between the terminal (60) described later and the electrode tab assembly (20). To this end, the end of the electrode tab assembly (20) may be connected to the lower part (51) of the busbar (50).

[0089] Such a busbar (50) can bring the electrode assembly (10) and the cap (30) into close contact. That is, the busbar (50) can prevent the formation of unnecessary space between the cap (30) and the electrode assembly (10). Through this, the energy density of the secondary battery (3) can be improved.

[0090] This is because the space between the cap (30) and the electrode assembly (10) is provided for the electrode tab assembly (20), and in this embodiment, some of the electrode tabs are flattened in the stacking direction (Z-axis direction) like the first electrode tab (22) by the bus bar (50), and the remaining parts are folded like the second electrode tab (24), so that the electrode tab assembly (20) can maintain a compact shape.

[0091] Meanwhile, in this embodiment, the busbar (50) is described as a metal section having a predetermined thickness. However, the structure or shape of the busbar (50) is not particularly limited as long as it can mediate the electrical connection between the terminal (60) and the electrode tab. For example, the busbar (50) may have a film shape extended in the stacking direction (Z-axis direction).

[0092] Referring to FIGS. 2 to 4, a secondary battery (3) according to the first embodiment of the present invention may include a terminal (60). The terminal (60) may be configured to conduct electricity to the outside of the electrode assembly (10). In this embodiment, the terminal (60) may be coupled through the cover portion (32) of the cap (30).

[0093] In this embodiment, one side of the terminal (60) may be exposed to the front of the cap (30) (positive direction of the X-axis). The other side of the terminal (60) may extend toward the electrode assembly (10). The other side of the terminal (60) may be coupled to the bus bar (50). For example, the terminal (60) may be welded to the bus bar (50), but is not limited thereto. The terminal (60) may be positioned opposite the electrode tab assembly (20) with the bus bar (50) in between.

[0094] A secondary battery (3) according to the first embodiment of the present invention may include a gasket (70). The gasket (70) may perform the function of insulating the space between the cover portion (32) and the terminal (60) and / or the function of preventing the electrolyte from leaking out. To this end, the gasket (70) may be made of rubber or plastic material, but is not limited thereto.

[0095] In this embodiment, the gasket (70) may include a gasket portion (72). The gasket portion (72) may be provided in a hollow shape. The gasket portion (72) may extend in the longitudinal direction (X-axis direction) of the electrode assembly (10).

[0096] At this time, the gasket portion (72) can be coupled through the cover portion (32). A terminal (60) can be coupled through the inner side of the gasket portion (72). As a result, the space between the cover portion (32) and the terminal (60) can be insulated and / or airtight.

[0097] In this embodiment, the gasket (70) may include a first gasket catch portion (74). The first gasket catch portion (74) may be provided at one end of the gasket portion (72). The first gasket catch portion (74) may be configured to catch on the outer surface of the cover portion (32). As an example, the first gasket catch portion (74) may have a shape with an outer diameter larger than that of the gasket portion (72), but is not limited thereto. As a result, the gasket portion (72) may not fall out to the outside of the cover portion (32).

[0098] In this embodiment, the gasket (70) may include a second gasket catch portion (76). The first gasket catch portion (76) may be provided at the other end of the gasket portion (72). The second gasket catch portion (76) may be configured to catch on the outer surface of the cover portion (32). As an example, the second gasket catch portion (76) may have a shape with an outer diameter larger than that of the gasket portion (72), but is not limited thereto. As a result, the gasket portion (72) may not fall out into the inner side of the cover portion (32).

[0099] Meanwhile, the secondary battery (3) according to the first embodiment of the present invention may include a fixing member (80). The fixing member (80) may be a member for connecting the gasket (70) and the terminal (60) to each other.

[0100] In this embodiment, the fixing member (80) may be interposed between the gasket (70) and the terminal (60). The fixing member (80) may have a rivet shape that grips the gasket (70). However, the structure or shape of the fixing member (80) is not particularly limited as long as it can relatively fix the gasket (70) and the terminal (60).

[0101] In this embodiment, the fixing member (80) may be made of a metal material. The fixing member (80) may be coupled to the terminal (60). For example, the fixing member (80) may be welded to the terminal (60). As a result, the fixing member (80) can fix the terminal (60) more strongly.

[0102] As previously explained, in the secondary battery (3) according to the first embodiment of the present invention, a bus bar (50) is provided between the cap (30) and the electrode assembly (10), so that the electrode tab assembly (20) can maintain a compact shape, and thus the energy density can be improved by bringing the cap (30) and the electrode assembly (10) into close contact. Furthermore, since the bus bar (50) mediates the electrical connection between the electrode tab assembly (20) and the terminal (60), the electrical current between the electrode assembly (10) and the outside can be stably maintained.

[0103] Hereinafter, a secondary battery according to another embodiment of the present invention will be described. At this time, the description will focus on the differences from the secondary battery according to the first embodiment described above. FIG. 5 is an enlarged cross-sectional view of the portion corresponding to part A of FIG. 3 in the secondary battery according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view of the secondary battery according to the third embodiment of the present invention cut according to II of FIG. 2.

[0104] FIG. 5 discloses a secondary battery according to a second embodiment of the present invention. Referring to FIG. 5, a fixing member (180) of a secondary battery (103) according to a second embodiment of the present invention may have one side extended rearward (negative direction of the X-axis) toward a bus bar (50).

[0105] At this time, one side of the fixed member (180) may come into contact with the bus bar (50). If necessary, one side of the fixed member (180) may be connected to the bus bar (50). As an example, one side of the fixed member (180) may be welded to the bus bar (50).

[0106] Accordingly, in the secondary battery (103) according to the present embodiment, the fixing member (180) not only relatively fixes the gasket (70) and the terminal (60), but also assists the terminal (60) in performing the function of assisting the electrical connection between the busbar (50) and an external power source or load. Through this, the structural stability and electrical connectivity of the secondary battery (103) can be improved.

[0107] FIG. 6 discloses a secondary battery according to a third embodiment of the present invention. Referring to FIG. 6, in the secondary battery (203) according to the third embodiment of the present invention, the electrode tabs of the electrode tab assembly (220) can be coupled to the outward surface (50a) of the bus bar (50). Thus, the bus bar (50) and the electrode assembly (10) can be in close contact. As a result, the length in the front-rear direction (X-axis direction) of the secondary battery (203) can be further reduced, and the energy density can be improved.

[0108] In this embodiment, the electrode assembly (10) may include a first electrode (12), a second electrode (14), a third electrode (16), and a fourth electrode (18). The first to fourth electrodes (12, 14, 16, 18) (hereinafter referred to as 12 to 18) may be stacked in an up-down direction (Z-axis direction). The second electrode (14) may be located below the first electrode (12) (negative direction of the Z-axis), the fourth electrode (18) may be located below the second electrode (14), and the third electrode (16) may be located below the fourth electrode (18). Alternatively, the first and second electrodes (12, 14) may be located above the third and fourth electrodes (16, 18) (positive direction of the Z-axis). Other electrodes may be interposed between each electrode.

[0109] In this embodiment, the electrode tab assembly (220) may include a first electrode tab (222), a second electrode tab (224), a third electrode tab (226), and a fourth electrode tab (228). The first to fourth electrode tabs (222, 224, 226, 228) (hereinafter referred to as 222 to 228) may each be an electrode tab extending from the first to fourth electrodes (12 to 18). The first and second electrode tabs (222, 224) may be located above the third and fourth electrode tabs (226, 228) (in the positive direction of the Z-axis).

[0110] In this embodiment, the first electrode tab (222) may extend from the first electrode (12) toward the upper part (53) of the bus bar (50). At this time, the end of the first electrode tab (222) may be coupled to the upper region of the outward surface (50a).

[0111] The second electrode tab (224) may include an electrode-side portion extending from the second electrode (14) toward the first electrode tab (222), a busbar-side portion extending toward the upper portion (53) of the busbar (50) and coupled to the upper portion (53), and a curved portion provided between the electrode-side portion and the busbar-side portion to connect them. At this time, the end of the busbar-side portion of the second electrode tab (224) may be coupled to the upper region of the outward-facing surface (50a).

[0112] In this embodiment, the third electrode tab (226) may extend from the third electrode (16) toward the lower part (51) of the bus bar (50). At this time, the end of the third electrode tab (226) may be coupled to the lower region of the outward surface (50a). Here, the lower region of the outward surface (50a) may refer to a region located relatively lower (in the negative direction of the Z-axis) than the aforementioned upper region.

[0113] The fourth electrode tab (228) may include an electrode-side portion extending from the fourth electrode (18) toward the third electrode tab (226), a busbar-side portion extending toward the lower part (51) of the busbar (50) and coupled to the lower part (51), and a curved portion provided between the electrode-side portion and the busbar-side portion to connect them. At this time, the end of the busbar-side portion of the fourth electrode tab (228) may be coupled to the lower region of the outward surface (50a). At this time, the first and second electrode tabs (222, 224) and the third and fourth electrode tabs (226, 228) may be formed to face each other in the vertical direction (Z-axis direction).

[0114] As such, in this embodiment, since the electrode tabs of the electrode tab assembly (220) are coupled to the outward surface (50a) of the bus bar (50), no space is required between the bus bar (50) and the electrode assembly (10) for coupling the bus bar and the electrode tabs. Accordingly, since the bus bar (50) and the electrode assembly (10) can be closely attached, the front-to-rear (X-axis direction) length of the secondary battery (203) is reduced, and the energy density can be improved.

[0115] 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.

[0116] [Explanation of the symbol]

[0117] 1: Battery box 2: Packaging

[0118] 3, 103: Secondary battery 10: Electrode assembly

[0119] 12: First electrode 14: Second electrode

[0120] 16: Third electrode 18: Fourth electrode

[0121] 20, 220: Electrode tab assembly

[0122] 22, 222: 1st electrode tab 24, 224: 2nd electrode tab

[0123] 25: Electrode side part 26: Busbar side part

[0124] 27: Curved part 30: Cap

[0125] 32: Cover part 34: Extension part

[0126] 36: Connection part 40: Exterior film

[0127] 50: Busbar 60: Terminal

[0128] 70: Gasket 72: Gasket section

[0129] 74: First gasket catch 76: Second gasket catch

[0130] 80, 180: Fixed member 226: Third electrode tab

[0131] 228: 4th electrode tab

Claims

1. An electrode assembly including a plurality of electrodes stacked on top of each other and extending in one direction; A cap covering one side in the extension direction of the above electrode assembly; An outer film that is coupled to the above cap and wraps the electrode assembly in a circumferential direction; A busbar positioned between the cap and the electrode assembly and extending in the stacking direction of the electrode; and It includes an electrode tab assembly extending from the above electrode assembly and coupled to the above busbar, and The above electrode tab assembly is, A first electrode tab extending from the electrode assembly toward a portion of the busbar; and A secondary battery comprising a second electrode tab including an electrode-side portion extending from the electrode assembly toward the first electrode tab and a busbar-side portion extending toward the part of the busbar.

2. In Paragraph 1, The above first and second electrode tabs are electrode tabs located at the outermost edge based on the stacking direction, in a secondary battery.

3. In Paragraph 1, The above electrode-side portion extends toward another part of the busbar, and A secondary battery in which the above-mentioned part of the busbar and the above-mentioned other part are positioned at a predetermined distance in the stacking direction.

4. In Paragraph 3, The above electrode assembly is, It includes a first electrode, The first electrode tab is connected to the first electrode, and The first electrode is a secondary battery, which is positioned closer to the other part among the one part and the other part of the busbar.

5. In Paragraph 3, The above electrode assembly is, It includes a second electrode, The second electrode tab is connected to the second electrode, and The second electrode is a secondary battery, which is located closer to the one part of the busbar than to the other part of the busbar.

6. In Paragraph 1, The above second electrode tab is, A secondary battery comprising a curved portion having a folded shape, connecting the electrode side portion and the busbar side portion.

7. In Paragraph 1, The first electrode tab above has a flat shape, The above second electrode tab is a secondary battery having a shape in which one part is folded so that the electrode side portion and the busbar side portion overlap.

8. In Paragraph 1, A secondary battery further comprising a terminal that is coupled through the above cap and conducts current with the above busbar.

9. In Paragraph 8, The above terminal is a secondary battery extending from the busbar toward the outside of the cap.

10. In Paragraph 8, A gasket provided between the above cap and the above terminal; and A secondary battery further comprising a fixing member for fixing the above gasket to the above cap.

11. In Paragraph 10, The above gasket is a secondary battery made of an insulating material.

12. In Paragraph 10, The above terminal extends in the above one direction, and The above gasket is, A secondary battery comprising a gasket portion that surrounds the above terminal in a circumferential direction.

13. In Paragraph 12, The above gasket portion is a secondary battery having a hollow shape.

14. In Paragraph 12, The above gasket is, A secondary battery comprising a first gasket catch portion provided on one side of the gasket portion and capable of engaging with one surface of the cap.

15. In Paragraph 14, The above gasket is, It includes a second gasket catch portion provided on the other side of the gasket portion and capable of engaging with the other surface of the cap, and The one side and the other side of the above cap are a secondary battery facing each other.

16. In Paragraph 10, The above-mentioned fixing member is a secondary battery having a rivet shape.

17. In Paragraph 10, The above-mentioned fixing member is a secondary battery provided between the gasket and the terminal.

18. In Paragraph 17, The above-mentioned fixed member and the above-mentioned terminal are welded together, forming a secondary battery.

19. In Paragraph 17, One side of the above-mentioned fixed member extends toward the electrode assembly and is coupled to the busbar, forming a secondary battery.

20. In Paragraph 1, The above busbar is, It includes an inwardly facing side of the electrode assembly, and The first and second electrode tabs are a secondary battery coupled to the inward surface.

21. In Paragraph 1, The above busbar is, It includes an outward-facing surface facing the cap side, and The first and second electrode tabs are a secondary battery coupled to the outward surface.

22. In Article 21, The above electrode tab assembly is, It includes third and fourth electrode tabs coupled to other parts of the busbar from the above electrode assembly, The above-mentioned fourth electrode tab is a secondary battery having a folded shape.

23. In Paragraph 22, The above part of the busbar is the lower part of the busbar, and The other part of the above busbar is the upper part of the above busbar, and The first and second electrode tabs are located above the third and fourth electrode tabs, forming a secondary battery.

24. Secondary battery; and It includes a packaging that accommodates the above secondary battery, and The above secondary battery is, An electrode assembly including a plurality of electrodes stacked together and extending in one direction; A cap covering one side in the extension direction of the above electrode assembly; An outer film that is coupled to the above cap and wraps the electrode assembly in a circumferential direction; A busbar positioned between the cap and the electrode assembly and extending in the stacking direction of the electrode; and It includes an electrode tab assembly extending from the above electrode assembly and coupled to the above busbar, and The above electrode tab assembly is, A first electrode tab extending from the electrode assembly toward a portion of the busbar; and A battery box comprising a second electrode tab including an electrode-side portion extending from the electrode assembly toward the first electrode tab and a busbar-side portion extending toward the part of the busbar.

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