Secondary battery

Abstract

The present invention provides a secondary battery capable of stably connecting a thin film tab to a current collecting member as the number of electrode assemblies increases. A secondary battery according to an aspect of the present invention includes: a plurality of electrode assemblies each including electrodes; a plurality of electrode tab bundles formed on the electrodes of each of the plurality of electrode assemblies; a current collecting unit coupled to the electrode tab bundles of the plurality of electrode assemblies; and a cap assembly. The current collecting unit may include: a support plate to which a connection terminal connected to an external terminal is coupled; a first current collecting plate to which a portion of the plurality of electrode tab bundles is coupled; and a second current collecting plate to which the remaining portion of the plurality of electrode tab bundles is coupled and which is disposed to be offset from the first current collecting plate.

Description

secondary battery

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0038280 dated March 25, 2025 and Korean Patent Application No. 10-2026-0010803 dated January 20, 2026, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0002] The present invention relates to a secondary battery capable of charging and discharging.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance secondary batteries capable of repeated charging and discharging is actively underway.

[0004] Currently commercialized rechargeable batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0005] These lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. Additionally, the lithium secondary battery comprises a positive plate and a negative plate coated with these positive and negative active materials, respectively; an electrode assembly in which the positive and negative plates are arranged with a separator in between; and an outer casing that seals and encloses the electrode assembly together with an electrolyte.

[0006] Meanwhile, lithium secondary batteries can be classified according to the shape of the battery case into can-type secondary batteries, in which the electrode assembly is embedded in a metal can, and pouch-type secondary batteries, in which the electrode assembly is embedded in a pouch of aluminum laminate sheets. Furthermore, can-type secondary batteries can be further classified into cylindrical batteries and prismatic batteries depending on the shape of the metal can.

[0007] In the case of prismatic batteries, multiple thin-film tabs connected to the electrode plates are assembled into a single pre-welded unit and then welded to the current collector. As the thickness of the electrode assembly increases, the length of the thin-film tabs required for pre-welding becomes longer, and it is necessary to stably connect these tabs to the current collector.

[0008] The objective of the present invention is to provide a secondary battery capable of increasing energy density per unit volume by reducing the space occupied by thin film tabs, etc., inside the case.

[0009] Another objective of the present invention is to provide a secondary battery capable of reducing resistance to current as the length of the thin film tab increases during the process in which current reaches the electrode assembly through an external terminal.

[0010] Another objective of the present invention is to provide a secondary battery capable of stably connecting a thin film tab and a current collector as the number of electrode assemblies increases.

[0011] A secondary battery according to one aspect of the present invention comprises a case, a plurality of electrode assemblies each comprising an electrode and accommodated in the case, a plurality of electrode tab bundles formed on each electrode of the plurality of electrode assemblies, a current collector unit coupled to the electrode tab bundles of the plurality of electrode assemblies, and a cap assembly that seals the case and has an external terminal connected to the current collector unit located thereon. The current collector unit may include a support plate to which a connection terminal connected to the external terminal is coupled, a first current collector unit located on one side of the support plate to which a portion of the plurality of electrode tab bundles is coupled, and a second current collector unit to which the remaining portion of the plurality of electrode tab bundles is coupled, located on the other side of the support plate or on the side of the first current collector unit, and arranged offset from the first current collector unit.

[0012] According to one aspect of the present invention, the first current collector plate and the second current collector plate may be arranged offset from each other on the same plane.

[0013] According to one aspect of the present invention, the side ends of the first current collector plate and the side ends of the second current collector plate adjacent to each other may be arranged offset from each other.

[0014] According to one aspect of the present invention, the side end of the first current collector plate and the side end of the second current collector plate may have a step difference.

[0015] According to one aspect of the present invention, the current collector plate may be arranged in the order of the support plate, the first support plate, and the second support plate.

[0016] According to one aspect of the present invention, the current collector plate may be arranged in the order of the first current collector plate, the support plate, and the second support plate.

[0017] According to one aspect of the present invention, the plurality of electrode assemblies includes a pair of first electrode assemblies and second electrode assemblies arranged side by side, and electrode tab bundles of the same polarity of the first electrode assembly and the second electrode assembly may be located adjacent to each other.

[0018] According to one aspect of the present invention, a portion of the electrode tab bundle of the same polarity of the first electrode assembly and a portion of the electrode tab bundle of the same polarity of the second electrode assembly may be coupled to the first current collector plate, and the remaining portion of the electrode tab bundle of the same polarity of the first electrode assembly and the remaining portion of the electrode tab bundle of the same polarity of the second electrode assembly may be coupled to the second current collector plate.

[0019] According to one aspect of the present invention, a portion of the electrode tab bundle of the first electrode assembly and a portion of the electrode tab bundle of the second electrode assembly are bent to face each other along the thickness direction of the electrode assembly and coupled to the first current collector plate, and the remaining portion of the electrode tab bundle of the first electrode assembly and the remaining portion of the electrode tab bundle of the second electrode assembly are bent to face each other along the thickness direction and coupled to the second current collector plate.

[0020] According to one aspect of the present invention, a portion of the electrode tab bundle of the first electrode assembly and a portion of the electrode tab bundle of the second electrode assembly may be arranged in a line along the thickness direction, and the remaining portion of the electrode tab bundle of the first electrode assembly and the remaining portion of the electrode tab bundle of the second electrode assembly may be arranged in a line along the thickness direction.

[0021] According to one aspect of the present invention, the part and the remaining part of the electrode tab bundle of the first electrode assembly may be arranged offset from each other, and the part and the remaining part of the electrode tab bundle of the second electrode assembly may be arranged offset from each other.

[0022] According to one aspect of the present invention, the first current collector plate and the second current collector plate may have the same area.

[0023] According to one aspect of the present invention, the first current collector plate and the second current collector plate may have the same shape.

[0024] According to one aspect of the present invention, the first current collector plate and the second current collector plate may have a rectangular shape.

[0025] According to one aspect of the present invention, the ends of the electrode tab bundles can be fixedly joined to each other by a first welding.

[0026] According to one aspect of the present invention, the end of the electrode tab bundle may be fixed on the first current collector plate or the second current collector plate by a second welding.

[0027] According to one aspect of the present invention, a second weld area formed at the end by the second weld may overlap at least partially with a first weld area formed at the end by the first weld.

[0028] According to one aspect of the present invention, the second welding area may be located within the first welding area.

[0029] According to one aspect of the present invention, an insulating holder that supports the current collector may be coupled to the lower part of the current collector.

[0030] According to one aspect of the present invention, the case or the cap assembly further comprises a vent portion formed therein, wherein the long axis direction of the vent portion may be parallel to or intersect with the width direction of the electrode assembly.

[0031] A secondary battery according to one embodiment of the present invention can increase energy density per unit volume by reducing the space occupied by thin film tabs, etc., inside the case.

[0032] In addition, a secondary battery according to one embodiment of the present invention can reduce resistance to current due to an increase in the length of the thin film tab during the process in which current reaches the electrode assembly through an external terminal.

[0033] In addition, a secondary battery according to one embodiment of the present invention can stably connect a thin film tab and a current collector as the number of electrode assemblies increases.

[0034] FIG. 1 is a perspective view illustrating a secondary battery according to a first embodiment of the present invention.

[0035] Figure 2 is a cross-sectional view taken along the line A1-A1 in Figure 1.

[0036] Figure 3 is a drawing showing the electrode assembly and electrode tab bundle illustrated in Figure 2.

[0037] Figure 4 is a plan view illustrating the electrode assembly shown in Figure 3.

[0038] FIG. 5 is a perspective view showing a current collector according to a first embodiment of the present invention.

[0039] Figure 6 is a plan view illustrating the current collector shown in Figure 5.

[0040] FIG. 7 is a perspective view illustrating a state in which a current collector is coupled to a plurality of electrode assemblies according to a first embodiment of the present invention.

[0041] Figure 8 is a cross-sectional view taken along the line A2-A2 in Figure 7.

[0042] FIG. 9 is a plan view illustrating the state in which an electrode tab bundle is coupled to a current collector according to the first embodiment of the present invention.

[0043] FIG. 10 is a perspective view illustrating a secondary battery including a vent portion that extends long in the thickness direction.

[0044] FIG. 11 is a plan view illustrating the state in which an electrode tab bundle is coupled to a current collector according to a second embodiment of the present invention.

[0045] FIG. 12 is a perspective view illustrating a state in which a current collector according to a second embodiment of the present invention is coupled to a plurality of electrode assemblies.

[0046] FIG. 13 is a perspective view showing a current collector according to a third embodiment of the present invention inserted into an insulating holder.

[0047] FIG. 14 is a perspective view illustrating the insulating holder of FIG. 13.

[0048] FIG. 15 is a cross-sectional view illustrating the combined state of the current collector and the electrode assembly of FIG. 13.

[0049] FIG. 16 is a perspective view illustrating a state in which a current collector according to a fourth embodiment of the present invention is coupled to a plurality of electrode assemblies.

[0050] FIG. 17 is a plan view illustrating the electrode assembly shown in FIG. 16.

[0051] FIG. 18 is a plan view illustrating the current collector shown in FIG. 16.

[0052] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0053] The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this invention, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0054] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that in the accompanying drawings, identical components are indicated by the same reference numerals whenever possible. Furthermore, detailed descriptions of known functions and configurations that may obscure the essence of the present invention will be omitted. For the same reason, some components in the accompanying drawings may be exaggerated, omitted, or schematically depicted.

[0055] FIG. 1 is a perspective view showing a secondary battery according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the secondary battery shown in FIG. 1 taken along A1-A1. FIG. 3 is a view showing an electrode assembly and an electrode tab bundle included in the secondary battery shown in FIG. 2. FIG. 4 is a plan view showing the electrode assembly shown in FIG. 3 arranged in a pair.

[0056] Referring to FIGS. 1 to 4, the secondary battery (10) may include at least one electrode assembly (500), a case (100) that accommodates the electrode assembly (500), a cap plate (21) coupled to the case (100), external terminals (23, 24) installed on the cap plate (21), an upper insulating member (29) disposed between the cap plate (21) and the electrode assembly (500), a vent portion (50) disposed on the cap plate (21), a sealing plug (28), and a current collector (300).

[0057] Each electrode assembly (500) performs charging and discharging and can be formed in various forms, such as an all-solid electrode assembly, a lithium-ion electrode assembly, or a sodium-ion electrode assembly. In this embodiment, the electrode assembly (500) may include two electrode assemblies. Each electrode assembly (500R, 500F) may be an electrode assembly having the same internal structure.

[0058] The electrode assembly (500) includes an anode (11A), a cathode (12A), and a separator (13A) interposed between the anode (11A) and the cathode (12A), and the anode (11A), separator (13A), and cathode (12A) may be formed in a stacked structure or in a structure wound in the form of a jelly roll.

[0059] Additionally, the electrode assembly (500) may be structured such that an anode (11A) and a cathode (12A) are alternately inserted between separators (13A) that are folded in a zigzag shape. Additionally, the electrode assembly (500) may be formed in various forms, such as an all-solid type without separators.

[0060] The positive electrode (11A) and the negative electrode (12A), which are electrodes, may include a coated portion, which is an area where an active material is applied to a metal foil, and a non-coated portion, where no active material is applied. The positive electrode non-coated portion (11R, 11T, 13R, 13T) may protrude from the side end of the positive electrode (11A), and the negative electrode non-coated portion (12R, 12T, 14R, 14T) may protrude from the side end of the negative electrode (12A). The positive electrode non-coated portion (11R, 11T, 13R, 13T) and the negative electrode non-coated portion (12R, 12T, 14R, 14T) may protrude in the same direction, but in the direction toward the cap plate (21), that is, in the longitudinal direction (z-axis direction) of the electrode assembly (500).

[0061] The positive electrode unpaired portions (11R, 11T, 13R, 13T) and the negative electrode unpaired portions (12R, 12T, 14R, 14T) are formed in a tab shape and can be spaced apart in the width direction (y-axis direction) of the electrode assembly (500). The positive electrode unpaired portions (11R, 11T, 13R, 13T) and the negative electrode unpaired portions (12R, 12T, 14R, 14T) can be stacked in the thickness direction (x-axis direction) of the electrode assembly (500). At this time, the stacked positive electrode unpaired portions (11R, 11T, 13R, 13T) may form a first electrode tab bundle (11R, 11T) and a third electrode tab bundle (13R, 13T) of the positive electrode, and the stacked negative electrode unpaired portions (12R, 12T, 14R, 14T) may form a second electrode tab bundle (12R, 12T) and a fourth electrode tab bundle (14R, 14T) of the negative electrode. Here, an electrode tab bundle refers to a plurality of unpaired portions arranged in a row.

[0062] In this embodiment, the first electrode assembly (500R) may include a plurality of first electrode tab bundles (11) of positive electrodes and a plurality of second electrode tab bundles (12) of negative electrodes spaced apart from each other.

[0063] A plurality of first electrode tab bundles (11) of the anode may be spaced apart from each other. Specifically, a plurality of first electrode tab bundles (11) may include a first-1 electrode tab bundle (11R) and a first-2 electrode tab bundle (11T) of the same polarity. The first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) are non-porous portions protruding from the side end of the anode (11A), and the positions at which the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) protrude from the anode (11A) may be different from each other.

[0064] The first-1 electrode tab bundle (11R) may be continuously stacked in a row in the thickness direction (x-axis direction), and the first-2 electrode tab bundle (11T) may also be continuously stacked in a row in the thickness direction (x-axis direction). However, the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) may be arranged offset from each other. That is, the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) may not be arranged in a row from each other.

[0065] A plurality of second electrode tab bundles (12) of the cathode may be spaced apart from each other. Specifically, the plurality of second electrode tab bundles (12) may include a second-1 electrode tab bundle (12R) and a second-2 electrode tab bundle (12T) of the same polarity. The second-1 electrode tab bundle (12R) and the second-2 electrode tab bundle (12T) are non-porous portions protruding from the side end of the cathode (12A), and the positions at which the second-1 electrode tab bundle (12R) and the second-2 electrode tab bundle (12T) protrude from the cathode (12A) may be different from each other.

[0066] The second-1 electrode tab bundle (12R) may be continuously stacked in a row in the thickness direction (x-axis direction), and the second-2 electrode tab bundle (12T) may also be continuously stacked in a row in the thickness direction (x-axis direction). However, the second-1 electrode tab bundle (12R) and the second-2 electrode tab bundle (12T) may be arranged offset from each other. That is, the second-1 electrode tab bundle (12R) and the second-2 electrode tab bundle (12T) may not be arranged in a row from each other.

[0067] In this embodiment, the second electrode assembly (500F) may have the same shape and structure as the first electrode assembly (500R). The second electrode assembly (500F) may include a plurality of third electrode tab bundles (13) of positive electrodes and a plurality of fourth electrode tab bundles (14) of negative electrodes spaced apart from each other.

[0068] A plurality of third electrode tab bundles (13) may have the same structure as the plurality of first electrode tab bundles (11) described above, and a plurality of fourth electrode tab bundles (14) may have the same structure as the plurality of second electrode tab bundles (12) described above. A description of the plurality of third electrode tab bundles (13) and the plurality of fourth electrode tab bundles (14) will be omitted.

[0069] Additionally, the first electrode tab bundle (11) of the positive electrode of the first electrode assembly (500R) and the third electrode tab bundle (13) of the positive electrode of the second electrode assembly (500F) can be electrically connected to the first external terminal (23) via the first current collector (310).

[0070] The second electrode tab bundle (12) of the negative electrode of the first electrode assembly (500R) and the fourth electrode tab bundle (14) of the negative electrode of the second electrode assembly (500F) can be electrically connected to the second external terminal (24) via the second current collector (330).

[0071] A detailed description of the combined structure of the first electrode tab bundle (11), the third electrode tab bundle (13), and the first current collector (310) in this embodiment, and the combined structure of the second electrode tab bundle (12), the fourth electrode tab bundle (14), and the second current collector (330), will be provided later.

[0072] A separator (13A) is placed between the positive electrode (11A) and the negative electrode (12A), and the separator (13A) prevents short circuits and enables the movement of ions. If the secondary battery (10) is made of an all-solid-state battery, a solid electrolyte may be placed between the positive electrode (11A) and the negative electrode (12A) instead of the separator (13A).

[0073] The case (100) may be formed in the shape of a box having an internal space for accommodating an electrode assembly (500). The case (100) may be formed in various shapes, such as prismatic or cylindrical. A plurality of electrode assemblies (500) may be inserted into the case (100).

[0074] An electrolyte can be accommodated together with an electrode assembly (500) inside the case (100). The electrolyte can be in the form of a liquid, solid, or gel.

[0075] The cap plate (21) is made of a plate material that covers the opening of the case (100) and may have a shape corresponding to the shape of the opening of the case (100). The cap plate (21) may be fixed to the case (100) by welding.

[0076] In the cap plate (21), an electrolyte injection port (H1) for injecting the electrolyte and a vent hole (H2) in which a vent portion (50) is installed may be formed. A sealing plug (28) that blocks the electrolyte injection port (H1) is installed in the electrolyte injection port (H1), and a vent portion (50) that opens at a preset pressure may be formed in the vent hole (H2).

[0077] In this embodiment, the vent portion (50) may extend in the width direction (y-axis direction). The vent portion (50) is formed in a shape that extends in the width direction (y-axis direction) and may have a shape such as a rectangle, an oblong, or a rounded rectangle.

[0078] Additionally, the vent portion (50) can be fixed to the cap plate (21) by welding. The vent portion (50) can be fixed to the lower surface of the cap plate (21), but it can also be fixed to the upper surface of the cap plate (21).

[0079] The vent portion (50) may include two side notches (52, 53) and a connecting notch (51) connecting the side notches (52, 53). The connecting notch (51) and the side notches (52, 53) may be formed as long, continuous grooves and may be formed as grooves having a trapezoidal cross-section. However, the present invention is not limited thereto, and the connecting notch (51) and the side notches (52, 53) may have cross-sections of various shapes, such as triangles or arcs.

[0080] The connecting notch (51) is formed in a curved shape and can form a wave shape or an S shape. The two side notches (52, 53) are formed in an arc shape and are formed convexly in opposite directions, but can protrude convexly toward the outer side in the width direction (y-axis direction) of the vent portion (50). The first side notch (52) and the second side notch (53) are connected to the connecting notch (51), and the first side notch (52) and the second side notch (53) have the same structure and can be arranged symmetrically.

[0081] In this embodiment, the vent section (50) is formed to extend along the width direction (y-axis direction), and the gap between the first collector section (310) and the second collector section (330) is formed large so that even if the vent section (50) is arranged in the width direction (y-axis direction), gas can be discharged smoothly without interference from the first collector section (310) and the second collector section (330).

[0082] Meanwhile, the vent portion (50) may be formed to extend along the thickness direction (x-axis direction) (see FIG. 10). In this case, the gap between the electrode tab bundles in each electrode assembly (500) can be formed large.

[0083] An upper insulating member (29) may be disposed on the lower part of the cap plate (21), and the upper insulating member (29) may be formed as a plate parallel to the cap plate (21) and may extend in the width direction (y-axis direction) of the electrode assembly (500).

[0084] External terminals (23, 24) are coupled to the cap plate (21), and one or two external terminals (23, 24) may be installed on the cap plate (21). When two external terminals (23, 24) are installed on the cap plate (21), the first external terminal (23) may be a positive terminal and the second external terminal (24) may be a negative terminal. When one external terminal is installed on the cap plate (21), the case (100) may be charged as a negative terminal.

[0085] The first external terminal (23) and the second external terminal (24) may be formed in the shape of a plate. An insulating gasket (25) may be installed between the first external terminal (23) and the cap plate (21), and an insulating gasket (26) may also be installed between the second external terminal (24) and the cap plate (21). Additionally, the gaskets (25, 26) may extend downward and be located between the current collector (310, 330) and the cap plate (21). The gaskets (25, 26) may be formed as a single component or divided into multiple components.

[0086] The first external terminal (23) and the second external terminal (24) are formed in a plate shape, and a hole may be formed in the center of the first external terminal (23) and the second external terminal (24) into which a connecting terminal (317, 337) of the first current collector (310) or the second current collector (330) is inserted.

[0087] FIG. 5 is a perspective view showing a current collector according to a first embodiment of the present invention, FIG. 6 is a plan view showing the current collector shown in FIG. 5, and FIG. 7 is a perspective view showing a state in which a current collector is coupled to a plurality of electrode assemblies according to a first embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line A2-A2 in FIG. 7, and FIG. 9 is a plan view showing a state in which an electrode tab bundle is coupled to a current collector according to a first embodiment of the present invention.

[0088] Referring to FIGS. 5 to 9, in this embodiment, a first electrode assembly (500R) and a second electrode assembly (500F) are stacked along the thickness direction (x-axis direction), and the first electrode tab bundle (11) of the positive electrode of the first electrode assembly (500R) and the third electrode tab bundle (13) of the positive electrode of the second electrode assembly (500F) are combined with the first current collector (310), and the second electrode tab bundle (12) and the fourth electrode tab bundle (14) of the negative electrode of the first electrode assembly (500R) can be combined with the second current collector (330).

[0089] In this embodiment, a plurality of electrode tab bundles (11, 12, 13, 14) formed on each electrode of the electrode assembly (500) may be arranged offset from each other. For example, the first electrode tab bundle (11) of a plurality of positive electrodes of the first electrode assembly (500R) may include a first-1 electrode tab bundle (11R) and a first-2 electrode tab bundle (11T), and the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) may be arranged offset from each other. As shown in FIGS. 3 and 4, the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) may be arranged offset from each other along the thickness direction (x-axis direction). Specifically, the first electrode tab bundle (11R) and the first electrode tab bundle (11T) may have different positions for the unseen portions protruding from the electrodes. That is, in this embodiment, the multiple unseen portions of the first electrode tab bundle (11) may not be arranged in a straight line but may be arranged offset from each other.

[0090] The second electrode tab bundle (12) of a plurality of negative electrodes of the first electrode assembly (500R) may include a second-1 electrode tab bundle (12R) and a second-2 electrode tab bundle (12T), and the second-1 electrode tab bundle (12R) and the second-2 electrode tab bundle (12T) may be arranged offset from each other.

[0091] In this embodiment, the first electrode tab bundle (11R) may be located adjacent to the outer side of the first electrode assembly (500R), and the second electrode tab bundle (11T) may be located adjacent to the inner side of the first electrode assembly (500R). Here, the inner side of the first electrode assembly (500R) may refer to the side facing the second electrode assembly (500F).

[0092] The second-1 electrode tab bundle (12R) may be located adjacent to the inner side of the first electrode assembly (500R), and the second-2 electrode tab bundle (12T) may be located adjacent to the outer side of the first electrode assembly (500R).

[0093] Additionally, in the first electrode assembly (500R), the first-1 electrode tab bundle (11R), the first-2 electrode tab bundle (11T), the second-2 electrode tab bundle (12T), and the second-1 electrode tab bundle (12R) can be arranged in order along the width direction (y-axis direction).

[0094] Meanwhile, the electrode tab bundles (13, 14) of the second electrode assembly (500F) can be arranged in the same way as the electrode tab bundles (11, 12) of the first electrode assembly (500R).

[0095] The third-1 electrode tab bundle (13R) may be located adjacent to the inner side of the second electrode assembly (500F), and the third-2 electrode tab bundle (13T) may be located adjacent to the outer side of the second electrode assembly (500F).

[0096] The 4-1 electrode tab bundle (14R) may be located adjacent to the outer side of the 2 electrode assembly (500F), and the 4-2 electrode tab bundle (14T) may be located adjacent to the inner side of the 2 electrode assembly (500F).

[0097] Additionally, in the second electrode assembly (500F), the third-1 electrode tab bundle (13R), the third-2 electrode tab bundle (13T), the fourth-2 electrode tab bundle (14T), and the fourth-1 electrode tab bundle (14R) can be arranged in order along the width direction (y-axis direction).

[0098] In this embodiment, the current collector (300) can be combined with the first to fourth electrode tab bundles (11, 12, 13, 14) and electrically connected to the external terminals (24, 24).

[0099] The current collector (300) may include a first current collector (310) coupled to a positive electrode tab bundle (11, 13) and a second current collector (330) coupled to a negative electrode tab bundle (12, 14). At this time, the first current collector (310) and the second current collector (330) may have the same shape and structure.

[0100] The first current collector (310) may include a support plate (311) on which the first connection terminal (317) is located, a first current collector plate (313) to which some of the plurality of electrode tab bundles (11, 13) are connected, and a second current collector plate (315) to which the remaining portion of the plurality of electrode tab bundles (11, 13) are connected. In this embodiment, the support plate (311), the first current collector plate (313), and the second current collector plate (315) may be arranged in a line in that order. The support plate (311) and the second current collector plate (315) may be arranged to the left and right, respectively, with the first current collector plate (313) at the center.

[0101] At this time, the support plate (311), the first current collector plate (313), and the second current collector plate (315) can form a single plane. Accordingly, the first current collector (310) can be made of a flat plate.

[0102] Meanwhile, the first collector plate (313) and the second collector plate (315) may have the same shape. For example, the first collector plate (313) and the second collector plate (315) may have a square or rectangular shape. In this case, the first collector plate (313) and the second collector plate (315) may have the same area.

[0103] The flatness of the first current collector (310) may be 0.05 to 2. Flatness indicates the degree of flatness of the first current collector (310), and the smaller the value, the flatter it is. If the flatness of the first current collector (310) exceeds 2, a part of the first current collector (310) may come into contact with the upper surface of the electrode assembly (500) located below, and a short circuit may occur. Therefore, if the flatness of the first current collector (310) is within the corresponding range, even if the electrode tab bundle (11, 13) is coupled to the upper surface of the first current collector (310), a short circuit with the electrode assembly (500) can be prevented.

[0104] A first connection terminal (317) connected to a first external terminal (23) may be attached to the upper surface of the support plate (311). The first connection terminal (317) may electrically connect the support plate (311) and the first external terminal (23). The first connection terminal (317) may be formed integrally with the support plate (311), or the first connection terminal (317) may be fixedly attached to the support plate (311) by welding or the like. Additionally, the first connection terminal (317) may be positioned by being inserted into or penetrating a groove or hole formed in the support plate (311).

[0105] The first connecting terminal (317) protruding from the upper surface of the support plate (311) can be inserted into a hole formed in the external terminal. The first connecting terminal (317) is column-shaped and can have various shapes of cross-sections, such as circular, square, pentagonal, or hexagonal.

[0106] In this embodiment, the support plate (311) may be located at the outermost side of the first current collector (310). Here, 'outer side' may refer to both ends in the width direction (y-axis direction) of the electrode assembly (500). The support plate (311) may be located adjacent to both ends in the width direction (y-axis direction) of the electrode assembly (500). Specifically, the support plate (311) of the first current collector (310) and the support plate (331) of the second current collector (330) may be located adjacent to both ends in the width direction (y-axis direction) of the electrode assembly (500). Accordingly, the first connection terminal (317) located on the support plate (311) of the first current collector (310) and the second connection terminal (337) located on the support plate (331) of the second current collector (330) can each be located adjacent to both ends in the width direction (y-axis direction) of the electrode assembly (500).

[0107] Meanwhile, the support plate (311) can be positioned approximately in the center of the thickness direction (x-axis direction) of the stacked first electrode assembly (500R) and the second electrode assembly (500F). By doing so, the first connection terminal (317) and the second connection terminal (337) located on the support plate (311) can be positioned approximately in the center of the thickness direction (x-axis direction) of the stacked first electrode assembly (500R) and the second electrode assembly (500F).

[0108] The first current collector plate (313) is located on the side of the support plate (311) so that a portion of the first electrode tab bundle (11) of the positive electrode of the first electrode assembly (500R) and a portion of the third electrode tab bundle (13) of the positive electrode of the second electrode assembly (500F) can be combined. Specifically, a first-1 electrode tab bundle (11R), which is a portion of the first electrode tab bundle (11) of the first electrode assembly (500R), and a third-1 electrode tab bundle (13R), which is a portion of the third electrode tab bundle (13) of the second electrode assembly (500F), can be combined.

[0109] The first current collector plate (313) may be positioned further toward the first electrode assembly (500R) than toward the second electrode assembly (500F). That is, when viewed from above, the area of ​​the first current collector plate (313) overlapping with the first electrode assembly (500R) may be larger than the area overlapping with the second electrode assembly (500F).

[0110] In this embodiment, the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) coupled to the first current collector plate (313) can be arranged in a line in the thickness direction (x-axis direction) of the electrode assembly (500).

[0111] At this time, the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R), arranged in a row, can be folded in a direction facing each other and coupled to the upper surface of the first current collector plate (313). The first-1 electrode tab bundle (11R) can be folded from top to bottom and coupled to the upper surface of the first current collector plate (313), and the third-1 electrode tab bundle (13R) can be folded from bottom to top and coupled to the upper surface of the first current collector plate (313). Here, 'top' refers to the outer side of the first electrode assembly (500R) in the thickness direction (x-axis direction), and 'bottom' refers to the outer side of the second electrode assembly (500F) in the thickness direction (x-axis direction).

[0112] In this embodiment, before being coupled to the upper surface of the first current collector plate (313), the first electrode tab bundle (11) of the anode is gathered in the center using a tab guide (not shown), and the gathered first electrode tab bundle (11) of the anode is fixed by a first weld. A first weld area (PW1) may be formed at the end of the first electrode tab bundle (11) of the anode by the first weld (see FIG. 3). Meanwhile, a first weld area may also be formed at the end of the third electrode tab bundle (13) of the second electrode assembly (500F), just as with the first electrode tab bundle (11). Additionally, a first weld area (PW2) may be formed at the end of the second electrode tab bundle (12) of the first electrode assembly (500R). In the same way as the second electrode tab bundle (12), a first welding area can also be formed in the fourth electrode tab bundle (14) of the second electrode assembly (500F).

[0113] The ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) can be joined to the first current collector plate (313) by a second welding. Specifically, the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) are bent and pressed against the upper surface of the first current collector plate (313), and then the second welding is performed on the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) so that the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) can be joined to the first current collector plate (313).

[0114] A second weld can be performed on the first welding area (PW1) of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) so that the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) can be joined to the upper surface of the first current collector plate (313). The second weld can be formed long along the width direction (y-axis direction). At this time, the second weld can have various shapes, such as a straight shape, a spiral shape, or a dot shape.

[0115] The second welding is a welding that fixes the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) to the upper surface of the first current collector plate (313). The second welding may correspond to a main welding that fixes and combines the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) on the first current collector plate (313). At this time, laser welding or ultrasonic welding may be applied for the second welding. Preferably, laser welding may be applied for the second welding.

[0116] Specifically, in this embodiment, the second welding area (MW1) formed at the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) by the second welding may overlap at least partially with the first welding area (PW1) formed at the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R). Preferably, the entire second welding area (MW1) may overlap with the first welding area (PW1). That is, the entire second welding area (MW1) may be located within the first welding area (PW1).

[0117] As shown in FIG. 9, the area of ​​the first welding region (PW1) can be formed larger than the area of ​​the second welding region (MW1). That is, the welding region formed by the first welding can be formed larger than the welding region formed by the second welding.

[0118] In this embodiment, the area of ​​the first welding area (PW1) may be 1.1 to 5 times the area of ​​the second welding area (MW1). Since the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) are joined together by the first welding before the second welding is performed, even if the area of ​​the second welding area (MW1) is smaller than the area of ​​the first welding area (PW1), the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) can be firmly joined to the upper surface of the first current collector plate (313). That is, the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) are firmly fixed in advance by the first welding, so even if only a part of the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) are fixed on the first current collector plate (313) by the second welding, the ends of the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) can be firmly fixed to the upper surface of the first current collector plate (313).

[0119] Meanwhile, the length (LD_PW) of the first welding area (PW1) in the width direction (y-axis direction) may be greater than the length (LD_MW) of the second welding area (MW1). Additionally, the thickness (TD_PW) of the first welding area (PW1) in the thickness direction (x-axis direction) may be greater than the thickness (TD_MW) of the second welding area (MW1). Accordingly, as described above, the area of ​​the first welding area (PW1) can be formed to be larger than the area of ​​the second welding area (MW1).

[0120] The second collector plate (315) may be located on opposite sides of the support plate (311) with the first collector plate (313) as the center. That is, in this embodiment, the first collector part (310) may be arranged in the order of the support plate (311), the first collector plate (313), and the second collector plate (315).

[0121] In the second current collector plate (315), the remaining portion of the first electrode tab bundle (11) of the positive electrode of the first electrode assembly (500R) and the remaining portion of the third electrode tab bundle (13) of the positive electrode of the second electrode assembly (500F) may be combined. Specifically, the first-2 electrode tab bundle (11T), which is the remaining portion of the first electrode tab bundle (11) of the first electrode assembly (500R), and the third-2 electrode tab bundle (13T), which is the remaining portion of the third electrode tab bundle (13) of the second electrode assembly (500F), may be combined.

[0122] Unlike the first current collector plate (313), the second current collector plate (315) may be positioned further toward the second electrode assembly (500F) than toward the first electrode assembly (500R). That is, when viewed from above, the area of ​​the second current collector plate (315) overlapping with the second electrode assembly (500F) may be larger than the area overlapping with the first electrode assembly (500R).

[0123] Accordingly, the adjacent sides of the first collector plate (313) and the second collector plate (315) of the first collector part (310) can be arranged offset from each other. That is, the first collector plate (313) and the second collector plate (315) of the first collector part (310) can form a stepped shape.

[0124] The first-2 electrode tab bundle (11T) and the third-2 electrode tab bundle (13T) coupled to the second current collector plate (315) can be arranged in a line in the thickness direction (x-axis direction) of the electrode assembly (500).

[0125] At this time, the first-2 electrode tab bundle (11T) and the third-2 electrode tab bundle (13T), arranged in a row, can be folded in a direction facing each other and coupled to the upper surface of the second current collector plate (315). The first-2 electrode tab bundle (11T) can be folded from top to bottom and coupled to the upper surface of the second current collector plate (315), and the third-2 electrode tab bundle (13T) can be folded from bottom to top and coupled to the upper surface of the second current collector plate (315). Here, 'top' refers to the outer side of the first electrode assembly (500R) in the thickness direction (x-axis direction), and 'bottom' refers to the outer side of the second electrode assembly (500F) in the thickness direction (x-axis direction).

[0126] In the same manner as the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) of the first current collector plate (313), the first-2 electrode tab bundle (11T) and the third-2 electrode tab bundle (13T) can be joined onto the second current collector plate (315) by first welding and second welding. Therefore, the description of the first-2 electrode tab bundle (11T) and the third-2 electrode tab bundle (13T) being joined to the second current collector plate (315) is omitted.

[0127] The second current collector (330) may include a support plate (331) on which the second connection terminal (337) is located, a first current collector plate (333) to which some of the plurality of electrode tab bundles (12, 14) are connected, and a second current collector plate (335) to which the remaining portion of the plurality of electrode tab bundles (12, 14) are connected. In this embodiment, the support plate (331), the first current collector plate (333), and the second current collector plate (335) may be arranged in a line. The second current collector plate (335) and the support plate (331) may be arranged to the left and right, respectively, with the first current collector plate (333) at the center.

[0128] A second connection terminal (337) connected to a second external terminal (24) may be attached to the upper surface of the support plate (331). The second connection terminal (337) may electrically connect the support plate (331) and the second external terminal (24). The second connection terminal (337) may be formed integrally with the support plate (331), or the first connection terminal (337) may be fixedly attached to the support plate (331) by welding or the like. Additionally, the first connection terminal (337) may be positioned by being inserted into or penetrating a groove or hole formed in the support plate (331).

[0129] The second connecting terminal (337) protruding from the upper surface of the support plate (331) can be inserted into a hole formed in the external terminal. The second connecting terminal (337) is column-shaped and can have various shapes of cross-sections, such as circular, square, pentagonal, or hexagonal.

[0130] Meanwhile, the support plate (331) can be positioned approximately in the center of the thickness direction (x-axis direction) of the stacked first electrode assembly (500R) and the second electrode assembly (500F). By doing so, the first connection terminal (317) and the second connection terminal (337) located on the support plate (331) can be positioned approximately in the center of the thickness direction (x-axis direction) of the stacked first electrode assembly (500R) and the second electrode assembly (500F).

[0131] The first current collector plate (333) is positioned on the side of the support plate (331) so that a portion of the second electrode tab bundle (12) of the negative electrode of the first electrode assembly (500R) and a portion of the fourth electrode tab bundle (14) of the negative electrode of the second electrode assembly (500F) can be combined. Specifically, a second-1 electrode tab bundle (12R), which is a portion of the second electrode tab bundle (12) of the first electrode assembly (500R), and a fourth-1 electrode tab bundle (14R), which is a portion of the fourth electrode tab bundle (14) of the second electrode assembly (500F), can be combined.

[0132] The first current collector plate (333) may be positioned further toward the second electrode assembly (500F) than toward the first electrode assembly (500R). That is, when viewed from above, the area of ​​the first current collector plate (333) overlapping with the second electrode assembly (500F) may be larger than the area overlapping with the first electrode assembly (500R).

[0133] In this embodiment, the second-1 electrode tab bundle (12R) and the fourth-1 electrode tab bundle (14R) coupled to the first current collector plate (333) can be arranged in a line in the thickness direction (x-axis direction) of the electrode assembly (500).

[0134] At this time, the second-1 electrode tab bundle (12R) and the fourth-1 electrode tab bundle (14R), arranged in a row, can be folded in a direction facing each other and coupled to the upper surface of the first current collector plate (333). The second-1 electrode tab bundle (12R) can be folded from top to bottom and coupled to the upper surface of the first current collector plate (313), and the fourth-1 electrode tab bundle (14R) can be folded from bottom to top and coupled to the upper surface of the first current collector plate (333). Here, 'top' refers to the outer side of the first electrode assembly (500R) in the thickness direction (x-axis direction), and 'bottom' refers to the outer side of the second electrode assembly (500F) in the thickness direction (x-axis direction).

[0135] In the same manner as the first-1 electrode tab bundle (11R) and the third-1 electrode tab bundle (13R) of the first collector plate (313) of the first collector part (310), the second-1 electrode tab bundle (12R) and the fourth-1 electrode tab bundle (14R) can be joined onto the first collector plate (333) by first welding and second welding. Therefore, the description of the second-1 electrode tab bundle (12R) and the fourth-1 electrode tab bundle (14R) being joined to the first collector plate (333) will be omitted.

[0136] The second collector plate (335) may be located on opposite sides of the support plate (331) with the first collector plate (333) as the center. That is, in this embodiment, the second collector part (330) may be arranged in the order of the support plate (331), the first collector plate (333), and the second collector plate (335).

[0137] In the second current collector plate (335), the remaining portion of the second electrode tab bundle (12) of the negative electrode of the first electrode assembly (500R) and the remaining portion of the fourth electrode tab bundle (14) of the negative electrode of the second electrode assembly (500F) may be combined. Specifically, the second-2 electrode tab bundle (12T), which is the remaining portion of the second electrode tab bundle (12) of the first electrode assembly (500R), and the fourth-2 electrode tab bundle (14T), which is the remaining portion of the fourth electrode tab bundle (14) of the second electrode assembly (500F), may be combined.

[0138] Unlike the first current collector plate (333), the second current collector plate (335) may be positioned further toward the first electrode assembly (500R) than toward the second electrode assembly (500F). That is, when viewed from above, the area of ​​the second current collector plate (335) overlapping with the first electrode assembly (500R) may be larger than the area overlapping with the second electrode assembly (500F).

[0139] The second-2 electrode tab bundle (12T) and the fourth-2 electrode tab bundle (14T) coupled to the second current collector plate (335) can be arranged in a line in the thickness direction (x-axis direction) of the electrode assembly (500).

[0140] At this time, the second-2 electrode tab bundle (12T) and the fourth-2 electrode tab bundle (14T), arranged in a row, can be folded in a direction facing each other and coupled to the upper surface of the second current collector plate (335). The second-2 electrode tab bundle (12T) can be folded from top to bottom and coupled to the upper surface of the second current collector plate (335), and the fourth-2 electrode tab bundle (14T) can be folded from bottom to top and coupled to the upper surface of the second current collector plate (335). Here, 'top' refers to the outer side of the first electrode assembly (500R) in the thickness direction (x-axis direction), and 'bottom' refers to the outer side of the second electrode assembly (500F) in the thickness direction (x-axis direction).

[0141] In the same manner as the second current collector plate (315) of the first current collector (310), the second-2 electrode tab bundle (12T) and the fourth-2 electrode tab bundle (14T) can be joined onto the second current collector plate (335) by first welding and second welding. Therefore, the description of the second-2 electrode tab bundle (12T) and the fourth-2 electrode tab bundle (14T) being joined to the second current collector plate (335) is omitted.

[0142]

[0143] Hereinafter, a secondary battery according to the second embodiment of the present invention will be described.

[0144] FIG. 11 is a plan view illustrating a state in which an electrode tab bundle is coupled to a current collector according to a second embodiment of the present invention, and FIG. 12 is a perspective view illustrating a state in which a current collector according to a second embodiment of the present invention is coupled to a plurality of electrode assemblies.

[0145] Referring to FIGS. 11 and 12, the secondary battery according to the second embodiment has the same structure as the secondary battery according to the first embodiment described above, except for the current collector (300), so a redundant description of the same configuration is omitted.

[0146] In this embodiment, the support plate (311) in the first current collection unit (310) may be positioned between the first current collection plate (313) and the second current collection plate (315). Accordingly, in the first current collection unit (310), the first current collection plate (313), the support plate (311), and the second current collection plate (315) may be arranged in that order.

[0147] Accordingly, the first connection terminal (317) located on the upper surface of the support plate (311) can be positioned between the first current collector plate (313) and the second current collector plate (315). Since the second current collector (330) also has the same shape and structure as the first current collector (310), a detailed description thereof will be omitted.

[0148] According to the present embodiment, as the support plate (311) is positioned between the first collector plate (313) and the second collector plate (315), the distance between the first collector plate (313) and the second collector plate (315) may be greater than the distance between the first collector plate (313) and the second collector plate (315) in the first embodiment described above.

[0149] Accordingly, the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) of the first electrode tab bundle (11) may be further separated in the width direction (y-axis direction). Likewise, the third-1 electrode tab bundle (13R) and the third-2 electrode tab bundle (13T) of the third electrode tab bundle (13) may be further separated in the width direction (y-axis direction).

[0150] As in the present embodiment, if the distance between the first-1 electrode tab bundle (11R) and the first-2 electrode tab bundle (11T) of the first electrode tab bundle (11) and the distance between the third-1 electrode tab bundle (13R) and the third-2 electrode tab bundle (13T) of the third electrode tab bundle (13) are increased, it may be easier to gather the first electrode tab bundle (11) or the third electrode tab bundle (13) or to weld them after gathering. If the distance between the electrode tab bundles is small, adjacent electrode tab bundles may be damaged during the process of gathering or welding each electrode tab bundle. Therefore, in the present embodiment, the support plate (311) is increased between the first current collector plate (313) and the second current collector plate (315) to prevent damage to other electrode tab bundles during the process of forming bundles or welding.

[0151]

[0152] A secondary battery according to the third embodiment of the present invention will be described below.

[0153] FIG. 13 is a perspective view showing a current collector according to a third embodiment of the present invention inserted into an insulating holder, FIG. 14 is a perspective view showing the insulating holder of FIG. 13, and FIG. 15 is a cross-sectional view showing a state in which the current collector of FIG. 13 and the electrode assembly are combined.

[0154] Referring to FIGS. 13 to 15, the secondary battery according to the third embodiment has the same structure as the secondary battery according to the first embodiment described above, except for the insulating holder (CH), so a redundant description of the same configuration is omitted.

[0155] In this embodiment, an insulating holder (CH) may be disposed on the lower surface of the first current collector (310). The insulating holder (CH) can support and fix the first current collector (310) on the lower surface of the first current collector (310). In this embodiment, the insulating holder (CH) coupled to the lower surface of the second current collector (330) has the same structure as the insulating holder (CH) of the first current collector (310), so a detailed description thereof will be omitted.

[0156] The insulating holder (CH) can prevent the shape of the first current collector (310) from being deformed or damaged during the welding process of the first electrode tab bundle (11) and the third electrode tab bundle (13) and the first current collector (310), or while the first current collector (310) is located inside the case (100).

[0157] When the support plate (311), the first current collector plate (313), and the second current collector plate (315) of the first current collector (310) are deformed, the support plate (311), the first current collector plate (313), and the second current collector plate (315) may come into contact with the upper surface of the electrode assembly (500), and the electrode assembly (500) may be damaged or short-circuited. Therefore, in this embodiment, the insulating holder (CH) supports and fixes the first current collector (310), thereby preventing the electrode assembly (500) or the first electrode tab bundle (11) and the second electrode tab bundle (12) from being damaged or short-circuited.

[0158] The insulating holder (CH) may have a shape corresponding to the shape of the first current collector (310). At this time, the insulating holder (CH) may accommodate the first current collector (310) inside. The insulating holder (CH) may support the first current collector (310) by wrapping around the bottom and side of the accommodated first current collector (310). To prevent the first current collector (310) accommodated inside from coming loose, a plurality of hooks (CH_H) may be arranged on the side of the insulating holder (CH). The first current collector (310) may be fixed inside the insulating holder (CH) by the plurality of hooks (CH_H).

[0159] A cut groove (CH_G) in which a portion of the side is cut may be formed on the side of the insulating holder (CH) so that the first electrode tab bundle (11) and the third electrode tab bundle (13) protruding from the electrode assembly (500) are bent and come into contact with the upper surface of the first current collector (310). When the first electrode tab bundle (11) and the third electrode tab bundle (13) protruding from the electrode assembly (500) are bent and the bent first electrode tab bundle (11) and the third electrode tab bundle (13) come into contact with the upper surface of the first current collector (310), the first electrode tab bundle (11) and the third electrode tab bundle (13) may not be interfered with by the side of the insulating holder (CH) by means of the cut groove (CH_G).

[0160] A portion of the side of the first current collector (310) housed within the insulating holder (CH) may be exposed by the cut groove (CH_G). The contact area between the first current collector (310), the first electrode tab bundle (11), and the third electrode tab bundle (13) may be increased by the cut groove (CH_G).

[0161]

[0162] Hereinafter, a secondary battery according to the fourth embodiment of the present invention will be described.

[0163] FIG. 16 is a perspective view illustrating a state in which a current collector according to a fourth embodiment of the present invention is coupled to a plurality of electrode assemblies, FIG. 17 is a plan view illustrating the electrode assembly illustrated in FIG. 16, and FIG. 18 is a plan view illustrating a current collector illustrated in FIG. 16.

[0164] Referring to FIGS. 16 to 18, the secondary battery according to the fourth embodiment has the same structure as the secondary battery according to the first embodiment described above, except for the current collector (300), so a redundant description of the same configuration is omitted.

[0165] In this embodiment, the first current collector plate (313) and the second current collector plate (315) constituting the current collector (300) may be symmetrical to each other with respect to an axis extending from the thickness direction (x-axis direction) of the electrode assembly (500).

[0166] The first current collector plate (313) of the first current collector (310) may be positioned further toward the first electrode assembly (500R) than toward the second electrode assembly (500F). That is, when viewed from above, the area of ​​the first current collector plate (313) of the first current collector (310) that overlaps with the first electrode assembly (500R) may be larger than the area that overlaps with the second electrode assembly (500F).

[0167] The second current collector plate (315) of the first current collector (310) may be positioned closer to the second electrode assembly (500F) than to the first electrode assembly (500R). That is, when viewed from above, the area of ​​the second current collector plate (315) of the first current collector (310) that overlaps with the second electrode assembly (500F) may be larger than the area that overlaps with the first electrode assembly (500R).

[0168] The first current collector plate (333) of the second current collector (330) may be positioned closer to the first electrode assembly (500R) than to the second electrode assembly (500F). That is, when viewed from above, the area of ​​the first current collector plate (333) of the second current collector (330) that overlaps with the first electrode assembly (500R) may be larger than the area that overlaps with the second electrode assembly (500F).

[0169] The second current collector plate (335) of the second current collector (330) may be positioned further toward the second electrode assembly (500F) than toward the first electrode assembly (500R). That is, when viewed from above, the area of ​​the second current collector plate (335) of the second current collector (330) that overlaps with the second electrode assembly (500F) may be larger than the area that overlaps with the first electrode assembly (500R).

[0170] Meanwhile, the first electrode tab bundle (11) and the second electrode tab bundle (12) of the first electrode assembly (500R) may be symmetrical to each other with respect to an axis extending in the thickness direction (x-axis direction) of the electrode assembly (500).

[0171] The third electrode tab bundle (13) and the fourth electrode tab bundle (14) of the second electrode assembly (500F) may be symmetrical to each other with respect to an axis extending in the thickness direction (x-axis direction) of the electrode assembly (500).

[0172] Although an embodiment of the present invention has been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the present invention as described in the claims, and such modifications and changes are also to be included within the scope of the rights of the present invention.

Claims

1. Case; A plurality of electrode assemblies, each comprising an electrode and housed in the above case; A plurality of electrode tab bundles formed on each electrode of the plurality of electrode assemblies above; A current collector coupled to the electrode tab bundle of the plurality of electrode assemblies; and A cap assembly that seals the above case and has an external terminal connected to the current collector located thereon; comprising The above current collector is, A support plate to which a connection terminal connected to the above external terminal is coupled, A portion of the plurality of electrode tab bundles is combined, and a first current collector plate located on one side of the support plate and A secondary battery comprising a second current collector plate that is positioned offset from the first current collector plate and is located on the other side of the support plate or on the side of the first current collector plate, wherein the remaining portion of the plurality of electrode tab bundles is combined.

2. In Paragraph 1, A secondary battery in which the first current collector plate and the second current collector plate are arranged offset from each other on the same plane.

3. In Paragraph 2, A secondary battery in which the side ends of the first current collector plate and the side ends of the second current collector plate, which are adjacent to each other, are arranged offset from each other.

4. In Paragraph 3, A secondary battery in which the side end of the first current collector plate and the side end of the second current collector plate form a step difference.

5. In Paragraph 1, The above current collector plate is A secondary battery arranged in the order of the above support plate, the above first support plate, and the above second support plate.

6. In Paragraph 1, The above current collector plate is, A secondary battery arranged in the order of the first current collector plate, the support plate, and the second support plate.

7. In Paragraph 1, The plurality of electrode assemblies includes a pair of first electrode assemblies and second electrode assemblies arranged side by side with each other, A secondary battery in which electrode tab bundles of the same polarity of the first electrode assembly and the second electrode assembly are located adjacent to each other.

8. In Paragraph 7, A portion of the electrode tab bundle of the same polarity of the first electrode assembly and a portion of the electrode tab bundle of the same polarity of the second electrode assembly are coupled to the first current collector plate, A secondary battery in which the remaining portion of the electrode tab bundle of the same polarity of the first electrode assembly and the remaining portion of the electrode tab bundle of the same polarity of the second electrode assembly are coupled to the second current collector.

9. In Paragraph 8, A portion of the electrode tab bundle of the first electrode assembly and a portion of the electrode tab bundle of the second electrode assembly are bent to face each other along the thickness direction of the electrode assembly and are coupled to the first current collector plate. A secondary battery in which the remaining portion of the electrode tab bundle of the first electrode assembly and the remaining portion of the electrode tab bundle of the second electrode assembly are bent to face each other along the thickness direction and coupled to the second current collector plate.

10. In Paragraph 9, A portion of the electrode tab bundle of the first electrode assembly and a portion of the electrode tab bundle of the second electrode assembly are arranged in a line along the thickness direction, A secondary battery in which the remaining portion of the electrode tab bundle of the first electrode assembly and the remaining portion of the electrode tab bundle of the second electrode assembly are arranged in a line along the thickness direction.

11. In Paragraph 10, The part and the remaining part of the electrode tab bundle of the first electrode assembly are arranged offset from each other, A secondary battery in which the electrode tab bundles of the second electrode assembly are arranged so as to be offset from each other.

12. In Paragraph 1, A secondary battery in which the first current collector plate and the second current collector plate have the same area.

13. In Paragraph 1, A secondary battery in which the first current collector plate and the second current collector plate have the same shape.

14. In Paragraph 13, A secondary battery in which the first current collector plate and the second current collector plate have a rectangular shape.

15. In Paragraph 1, A secondary battery in which the ends of the electrode tab bundle are fixedly joined to each other by a first welding.

16. In Paragraph 15, A secondary battery in which the end of the electrode tab bundle is fixed on the first current collector plate or the second current collector plate by a second welding.

17. In Paragraph 16, A secondary battery in which the second weld area formed at the end by the second weld overlaps at least partially with the first weld area formed at the end by the first weld.

18. In Paragraph 17, The second welding area is a secondary battery located within the first welding area.

19. In Paragraph 1, A secondary battery in which an insulating holder supporting the current collector is coupled to the lower part of the current collector.

20. In Paragraph 1, It further includes a vent portion formed in the above case or the above cap assembly, and A secondary battery in which the long axis direction of the above-mentioned vent portion is parallel to or intersects the width direction of the above-mentioned electrode assembly.

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