Secondary battery, battery module having same, and method of manufacturing same

Abstract

Disclosed are: a secondary battery in which a current collecting plate and an electrode terminal are joined outside an accommodation can; and a method of manufacturing same. The secondary battery comprises: the accommodation can, which includes a bottom plate having a through hole and a terminal unit which is fixed to the bottom plate so as to be inserted into the through hole and has a terminal hole in a central portion; a cylindrical electrode assembly which is accommodated in the accommodation can and stores electrochemical energy, and in which a core cavity is positioned in a central portion; and the current collecting plate which is joined to one end of the electrode assembly so as to be exposed to the outside of the accommodation can via the terminal hole, and has a chamfered surface along the circumference of the terminal hole, wherein the terminal unit and the current collecting plate are joined by a welding bead that is positioned lower than the terminal unit and inside a welding recess defined by the chamfered surface and the inner surface of the terminal hole.

Description

Secondary battery, battery module including same, and manufacturing method thereof

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0100537, dated July 29, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a secondary battery, a battery module including the same, and a method for manufacturing the same, and more particularly, to a secondary battery including a rivet electrode terminal, a battery module including the same, and a method for manufacturing the same.

[0003] Recently, tab-less secondary batteries (hereinafter, "tab-less batteries") have been proposed to improve the capacity of secondary batteries. Tab-less batteries are secondary batteries that eliminate the separate connecting tabs that electrically connect the electrode assembly and electrode terminals, thereby reducing resistance loss at the connecting tabs and improving battery capacity.

[0004] For example, a tab-less battery can be provided as a cylindrical secondary battery having an electrode assembly in which a positive electrode plate and a negative electrode plate are wound in a jelly-roll shape, with the non-conductive portion of the electrode plate being divided into a plurality of segmented pieces and separated from each other by a separator.

[0005] A plurality of split pieces are formed at both ends of the electrode assembly into a plurality of split non-conductive portions having surfaces perpendicular to the axial direction of the electrode assembly, and are connected to the electrode terminals and the battery can, respectively, by the current collector plate to function as a secondary battery. Accordingly, the split non-conductive portions function as connection tabs of the tab-less battery.

[0006] The positive electrode of the electrode assembly housed in the battery can is connected to the positive terminal, which is a rivet-type electrode terminal that penetrates the bottom surface of the battery can, through the positive electrode collector plate, and the negative electrode of the electrode assembly is connected to the battery can itself through the negative electrode collector plate. Accordingly, the battery can function as a negative terminal while providing a accommodating space for the electrode assembly.

[0007] In particular, unlike typical cylindrical secondary batteries in which the positive terminal is placed on a cap assembly that covers the open end of the battery can, in tab-less batteries the positive terminal is placed in a rivet shape that penetrates the bottom of the battery can.

[0008] Accordingly, a positive terminal having a rivet structure that penetrates the bottom is placed in the battery can, and the battery can is inserted so that the positive current collector plate welded to the positive electrode contacts the positive terminal, and then the positive current collector plate is welded to the positive terminal with a welding tip inserted into the core cavity of an electrode assembly having a jelly-roll shape, thereby completing a tab-less battery.

[0009] However, since welding of the positive electrode collector is performed by a welding tip inserted into the core cavity, the electrode assembly is damaged by welding byproducts generated during the welding process, shortening the lifespan of the secondary battery. Furthermore, because the core cavity must be formed to a minimum size capable of accommodating the welding tip, there are inherent limitations to improving the energy density of the electrode assembly.

[0010] Accordingly, a new tab-less battery and a method for manufacturing the same are required that can prevent damage to the electrode assembly due to welding byproducts and improve energy density by reducing the size of the core cavity.

[0011] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0012] The present invention has been proposed to solve the above-described problems, and an object of the present invention is to provide a secondary battery capable of reducing welding damage to an electrode assembly and improving energy density by welding a positive terminal and a current collector plate from the outside of the electrode assembly.

[0013] Another object of the present invention is to provide a battery module including a secondary battery as described above.

[0014] Another object of the present invention is to provide a manufacturing method for manufacturing a secondary battery as described above.

[0015] The technical objectives of the invention are not limited to the purposes mentioned above. Other objectives and advantages of the invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the invention. Furthermore, it will be readily apparent that the objectives and advantages of the invention can be realized by the means and combinations thereof set forth in the claims.

[0016] According to one embodiment of the present disclosure for achieving the above object, a secondary battery includes a bottom plate having a through hole positioned therein, a receiving can having a terminal unit fixed to the bottom plate to be inserted into the through hole and having a terminal hole in a central portion, a cylindrical electrode assembly accommodated in the receiving can to store electrochemical energy and having a core hollow positioned in the central portion, and a current collector plate joined to one end of the electrode assembly so as to be exposed to the outside of the receiving can by penetrating the terminal hole and having a chamfered surface along the circumference of the terminal hole, wherein the terminal unit and the current collector plate are positioned inside a welding recess defined by the chamfered surface and an inner surface of the terminal hole and can be joined by a welding bead positioned lower than the terminal unit.

[0017] As one embodiment, the terminal unit may include a terminal insulator that is inserted into the through hole to cover the outer surface and the inner surface of the bottom plate adjacent to the through hole and provides an insulating hole having a size smaller than the through hole, and an electrode terminal that is inserted into the insulating hole to surround the terminal insulator and provides the terminal hole having a size smaller than the insulating hole at a central portion.

[0018] As one embodiment, the current collector plate may include a tab current collector that is joined to the electrode assembly, and a terminal current collector that is joined to the electrode terminal and has a protruding rod that protrudes upward along an axial direction in which an imaginary central axis of the receiving can extends from an upper central region of the tab current collector and is inserted into the terminal hole and has the chamfered surface in an edge region.

[0019] In one embodiment, the electrode terminal includes an upper flange that covers a first terminal surface, which is a surface of the terminal insulator adjacent to an outer surface of the bottom plate, and is located outside the receiving can, a lower flange that covers a second terminal surface, which is a surface of the terminal insulator adjacent to an inner surface of the bottom plate, and is located inside the receiving can, and a connecting cylinder that is connected to the upper flange and the lower flange and covers a side surface of the insulating hole, and the protruding rod can be positioned such that a rod surface exposed to the outside through the terminal hole forms the same plane as a surface of the upper flange along a radial direction of the receiving can.

[0020] As one embodiment, the chamfered surface may be arranged to be inclined downward along the axial direction from the load surface, so that the welding recess may have a ring shape that is defined by the inner surface of the connecting cylinder provided as the inner surface of the terminal hole and the chamfered surface and extends along the circumferential direction of the receiving can surrounding the axial direction.

[0021] As an example, the welding recess may have a depth of 0.4 mm to 0.6 mm in the axial direction from the rod surface and a width of 0.2 mm in the radial direction from the surface of the adjacent connecting cylinder.

[0022] As one embodiment, the protruding rod may be inserted into the terminal hole so as to have a gap with the connecting cylinder, such that the welding bead may have a bead body positioned in the welding recess and a bead leg extending from the bead body along the gap.

[0023] As an example, the gap may range from 0.01 mm to 0.02 mm, and the length of the weld bead may range from 40% to 60% of the terminal thickness, which is the distance between the outer surface of the upper flange and the inner surface of the lower flange.

[0024] As one embodiment, the device may further include an insulating disk disposed on the inner surface of the base plate to surround the terminal unit and electrically isolate the terminal collector and the base plate.

[0025] As an example, the electrode terminal may include a rivet electrode that penetrates the insulating hole and is secured to the terminal insulator by a rivet connection.

[0026] As an example, the secondary battery may further include an additional current collector plate that is electrically connected to the other end of the electrode assembly symmetrically positioned along the axial direction and partially connected to the receiving can, and a sealing cap that covers the additional current collector plate and seals it from the outside.

[0027] As an example, the receiving can may have a cylindrical shape having a height and a diameter, and a form factor, which is a ratio of the diameter to the height, may be in a range of 0.4 and 0.6.

[0028] According to another embodiment of the present disclosure for achieving the above object, a battery module includes a case having a plurality of battery holders therein, a plurality of secondary batteries stored in the battery holders, and a bus bar connected to the plurality of secondary batteries to apply charge and discharge current, wherein each of the plurality of secondary batteries includes a receiving can including a bottom plate having a through hole and a terminal unit disposed on the bottom plate to be inserted into the through hole, the terminal unit having a terminal hole in a central portion, and electrically connected to the bus bar, an electrode assembly having a cylindrical shape that is received in the receiving can to store electrochemical energy and has a core hollow portion in the central portion, and a current collector plate that is electrically connected to one end of the electrode assembly and is exposed to the outside of the receiving can by penetrating the terminal hole and having a chamfered surface along the circumference of the terminal hole, wherein the terminal unit and the current collector plate are positioned within a welding recess defined by the chamfered surface and an inner surface of the terminal hole and can be joined by a welding bead positioned lower than the terminal unit.

[0029] In one embodiment, the terminal unit may include a terminal insulator that is inserted into the through hole to cover an outer surface and an inner surface of the bottom plate adjacent to the through hole and provides an insulating hole having a size smaller than the through hole, and an electrode terminal that is inserted into the insulating hole to surround the terminal insulator and has the terminal hole provided at a central portion having a size smaller than the insulating hole, and the current collector plate may include a tab current collector that is joined to the electrode assembly and a terminal current collector that has a protruding rod that protrudes upward along an axial direction in which an imaginary central axis of the receiving can extends from an upper portion of a central region of the tab current collector and is inserted into the terminal hole and has the chamfered surface at an edge region.

[0030] In one embodiment, the electrode terminal includes an upper flange that covers an outer surface of the terminal insulator and is exposed to the outside, a lower flange that covers an inner surface of the terminal insulator and is positioned inside the receiving can, and a connecting cylinder that is connected to the upper flange and the lower flange and covers an inner surface of the insulating hole, and the protruding rod is positioned such that a rod surface exposed to the outside through the terminal hole forms the same plane as a surface of the upper flange along a radial direction of the receiving can, so that the bus bar can be in contact with the rod surface and the surface of the upper flange simultaneously, and the welding bead can be positioned at a lower portion of the bus bar.

[0031] A method for manufacturing a secondary battery according to another embodiment of the present disclosure for achieving the above object may include the steps of forming a receiving can including a bottom plate having a through hole and a terminal unit disposed on the bottom plate to be inserted into the through hole, the terminal unit having a terminal hole in the center and electrically connected to an external load, a step of forming a cylindrical electrode assembly having a current collector plate having a protruding rod having a chamfered surface disposed in an edge region and an additional current collector plate joined to both ends and storing electrochemical energy, a step of inserting the electrode assembly, to which the current collector plate is joined such that the protruding rod penetrates the terminal hole and is exposed to the outside of the receiving can, into the receiving can to provide a welding recess defined by the chamfered surface and an inner surface of the terminal hole along the circumference of the terminal hole, and a step of welding the current collector plate and the terminal unit on the outside of the receiving can to form a welding bead integrally joined to the current collector plate and the terminal unit inside the welding recess.

[0032] In one embodiment, the step of forming the receiving can may include the step of forming a terminal insulator that is inserted into the through hole to cover an outer surface and an inner surface of the bottom plate adjacent to the through hole and provides an insulating hole having a size smaller than the through hole, and the step of forming an electrode terminal that is inserted into the insulating hole to surround the terminal insulator and has the terminal hole provided at a central portion having a size smaller than the insulating hole, the electrode terminal including an upper flange that covers an outer surface of the terminal insulator and is exposed to the outside, a lower flange that covers an inner surface of the terminal insulator and is positioned inside the receiving can, and a connecting cylinder that is connected to the upper flange and the lower flange and covers an inner surface of the insulating hole.

[0033] As one embodiment, the electrode assembly may be inserted into the receiving can so as to have a gap with the inner surface of the connecting cylinder, the welding recess may be formed to communicate with the gap, and the welding bead may be formed to extend from the welding recess along the gap.

[0034] As an example, the weld bead may be formed to be positioned lower than the outer surface of the upper flange that is exposed to the outside, and to have a length in the range of 40% to 60% of the terminal thickness, which is the distance between the outer surface of the upper flange and the inner surface of the lower flange.

[0035] As an example, the electrode terminal may be secured to the terminal insulator by a rivet joint penetrating the insulating hole.

[0036] According to the secondary battery according to the present disclosure, the battery module including the same, and the manufacturing method thereof, terminal welding is performed on the outside of the receiving can, thereby achieving improvement in energy density by reducing the size of the core cavity and reducing damage to the electrode assembly due to welding byproducts compared to conventional terminal welding performed in the core cavity.

[0037] In particular, the current collector plate can be formed to have a protruding rod that penetrates a terminal hole provided in the electrode terminal and has a ring-shaped chamfered surface on the periphery, thereby providing a welding recess of relatively large size along the periphery of the through hole.

[0038] By adjusting the welding characteristics of the terminal welding, the welding bead can be formed to be located inside the welding recess at a level lower than the upper surface of the electrode terminal and the rod surface of the protruding rod.

[0039] Accordingly, by removing the welding beads from the upper surface of the electrode terminal and the load surface, the contact characteristics between the secondary battery and the bus bar in the battery module can be improved. Accordingly, the operational stability of the battery module can be enhanced.

[0040] However, the effects that can be obtained through the present disclosure are not limited to the effects described above, and other technical effects not mentioned above can be clearly understood by those skilled in the art from the specific contents for implementing the invention described below.

[0041] The following drawings attached to this specification illustrate preferred embodiments of the present disclosure and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present disclosure, and therefore, the present disclosure should not be interpreted as being limited to matters described in such drawings.

[0042] FIG. 1 is a perspective view showing a secondary battery according to one embodiment of the present disclosure.

[0043] Fig. 2 is a cross-sectional view taken along line I-I' of the secondary battery illustrated in Fig. 1.

[0044] FIG. 3 is a perspective view showing an electrode assembly included in the secondary battery illustrated in FIG. 1.

[0045] Figure 4 is a cross-sectional view showing the battery can illustrated in Figure 1.

[0046] FIG. 5 is a perspective view showing an electrode terminal illustrated in FIG. 4 according to one embodiment of the present disclosure.

[0047] Fig. 6 is a perspective view showing a plate laminate structure in which the electrode assembly illustrated in Fig. 3 is deployed.

[0048] Fig. 7 is an exploded perspective view showing the plate laminate structure illustrated in Fig. 6.

[0049] FIG. 8 is a perspective view showing a current collector plate arranged at one end of the electrode assembly illustrated in FIG. 3 according to one embodiment of the present disclosure.

[0050] Fig. 9 is a cross-sectional view taken along line II-II' of the collector plate illustrated in Fig. 8.

[0051] Fig. 10 is a cross-sectional view taken along line III-III' of the collector plate illustrated in Fig. 8.

[0052] FIG. 11 is a perspective view showing an additional collector plate arranged at the other end of the electrode assembly illustrated in FIG. 3 according to one embodiment of the present disclosure.

[0053] Fig. 12 is a drawing showing in detail the joint structure of the electrode terminal and the protruding rod included in the secondary battery illustrated in Fig. 2.

[0054] Fig. 13 is a perspective view showing the joint relationship between the electrode terminal and the protruding rod shown in Fig. 12 before performing terminal welding.

[0055] Fig. 14 is an enlarged cross-sectional view of the welding recess illustrated in Fig. 13.

[0056] Fig. 15 is a perspective view showing a battery module having the secondary battery illustrated in Fig. 1.

[0057] Fig. 16 is a cross-sectional view showing the contact state of the secondary battery and the bus bar illustrated in Fig. 15.

[0058] FIG. 17 is a flowchart illustrating a method for manufacturing a secondary battery disclosed in FIG. 1 according to one embodiment of the present disclosure.

[0059] Figures 18 to 23 are process cross-sectional views showing a method for manufacturing a secondary battery illustrated in Figure 17.

[0060] [Explanation of symbols]

[0061] 100: Receiving can 110: Bottom plate 120: Side wall 130: Terminal unit 131: Terminal insulator 132: Electrode terminal 200: Electrode assembly 210: First electrode plate 220: Second electrode plate 230: Separator 300: Current collector plate 310: First tab current collector 311: Lower current collector strap 320: Terminal current collector 321: Upper current collector strap 322: Protruding rod 330: Connecting ring 350: Additional current collector plate 351: Second tab current collector 352: Can current collector 500: Secondary battery 600: Case 700: Bus bar 1000: Battery module 2000: Method for manufacturing a secondary battery.

[0062] The above-described objects, features, and advantages are described in detail with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0063] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0064] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0065] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0066] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0067] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0068] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C to D", this means C or more and D or less, unless otherwise stated.

[0069] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. In the present disclosure, the axial direction (z) represents the direction in which an imaginary central axis passing through the center of a disk or cylinder shape extends, and the radial direction (r) represents a direction approaching (centripetal) or moving away (centrifugal) from the center of the disk or cylinder shape. In addition, the circumferential direction (θ) represents a direction surrounding an imaginary central axis passing through the center of the disk or cylinder shape.

[0070] FIG. 1 is a perspective view showing a secondary battery according to one embodiment of the present disclosure, and FIG. 2 is a cross-sectional view taken along line I-I' of the secondary battery shown in FIG. 1. FIG. 3 is a perspective view showing an electrode assembly included in the secondary battery shown in FIG. 1, and FIG. 4 is a cross-sectional view showing a battery can shown in FIG. 1.

[0071] Referring to FIGS. 1 to 4, a secondary battery (500) according to one embodiment of the present disclosure includes a receiving can (100) having a terminal unit (130), an electrode assembly (200) received in the receiving can (100), and a current collector (300) joined to one end of the electrode assembly (200), and the terminal unit (130) and the current collector (300) can be joined by a welding process performed outside the receiving can (100).

[0072] As an example, the receiving can (100) is provided in a cylindrical shape having a bottom plate (110) in which a through hole (PH) is positioned and a side wall (120) extending along an axial direction (z), which is a direction in which an imaginary central axis of the receiving can (100) extends from the bottom. In particular, an end of the receiving can (100) facing the bottom plate (110) may be opened so that the receiving space (S), which is an internal space of the receiving can (100), may be provided as an open end (OP) communicating with the outside.

[0073] The bottom plate (110) is formed of a flat plate having a sufficient thickness and is provided as a base plate on which the terminal unit (130) is positioned, and a side wall (120) can extend along the axial direction (z) along the perimeter of the bottom plate (110).

[0074] The side wall (120) may be arranged along the perimeter of the floor plate (110) to define a receiving space (S) together with the floor plate (110). Accordingly, the side wall (120) may be provided in a shape corresponding to the perimeter of the floor plate (110). One end of the side wall (120) may be opened to form an open end (OP).

[0075] The bottom plate (110) and the side wall (120) may be provided in various shapes depending on the configuration of the receiving can (100). In the present embodiment, the receiving can (100) may be provided in a cylindrical shape. Accordingly, the bottom plate (110) may be provided as a circular plate, and the side wall (120) may be provided as a wall body connected to the perimeter of the circular plate, so that the receiving can (100) may be provided as a hollow cylinder.

[0076] In particular, the receiving can (100) may be set to have a form factor, which is the ratio of the diameter of the bottom plate (110) to the height of the side wall (120), in a range of about 0.4 to 0.6. For example, when the diameter of the bottom plate (110) of the receiving can (100) is 46 mm, the height of the side wall (120) may be set to 80 mm or 95 mm.

[0077] An end of the receiving can (100) facing the floor plate (110) along the axial direction (z) may be provided with an opening to be opened and serve as an open end (OP). Accordingly, the receiving space (S) of the receiving can (100) may be communicated with the outside through the open end (OP).

[0078] The electrode assembly (200) can be accommodated in or removed from the receiving can (100) through the open end (OP). The electrode assembly (200) accommodated in the receiving can (100) is fixed to the bottom plate (110) so as to be joined to the terminal unit (130) as described below. Accordingly, the end of the receiving can (100) symmetrically positioned with respect to the open end (OP) along the axial direction (z) and where the bottom plate (110) is positioned is provided as a sealed end (CP) that seals the receiving space (S).

[0079] The receiving can (100) can be made of various materials as long as it can protect the electrode assembly (200) stored in the receiving space (S) from external impact and can accommodate the electrolyte. For example, the receiving can (100) can be made of steel or an alloy thereof, or aluminum or an aluminum alloy.

[0080] In particular, a through hole (PH) is arranged in the central portion of the bottom plate (110) to which a terminal unit (130) is coupled. The through hole (PH) may be provided in various shapes as long as it can stably connect the terminal unit (130). In the present embodiment, the through hole (PH) is provided as a circular hole arranged in the central portion of the bottom plate (110).

[0081] A terminal unit (130) for electrically connecting an electrode assembly (200) placed in an external load and a receiving space (S) can be connected to a floor plate (110) by penetrating a through hole (PH).

[0082] The external load is composed of an energy-consuming load for utilizing stored energy when the secondary battery (500) is discharged, and may include an energy storage unit that stores greater energy than the secondary battery (500) when the secondary battery (500) is charged.

[0083] For example, the terminal unit (130) may include a terminal insulator (131) that is inserted into the through hole (PH) to cover the bottom plate (110) around the through hole (PH) and has an insulating hole (IH), and an electrode terminal (132) that penetrates the insulating hole (IH) and covers the terminal insulator (131).

[0084] The terminal insulator (131) may be inserted into the through hole (PH) to cover the outer surface (121) and the inner surface (122) of the bottom plate (110) adjacent to the through hole (PH), and may provide an insulating hole (IH) having a smaller size than the through hole (PH). Accordingly, the terminal insulator (131) may cover the inner surface of the through hole (PH) and the outer surface (121) and the inner surface (122) of the bottom plate (110) connected to the inner surface, and the insulating hole (IH) may be arranged in the center.

[0085] The terminal insulator (131) may be made of an elastic insulator to electrically insulate the receiving can (100) and the electrode terminal (132) and to attenuate an external force applied to the receiving can (100). For example, the terminal insulator (131) may include a polymer resin having electrical insulation properties and elasticity.

[0086] The electrode terminal (132) can be inserted into an insulating hole (IH) surrounding a terminal insulator (131) and fixed to the base plate (110). A terminal hole (TH) having a smaller size than the insulating hole (IH) is arranged in the center of the electrode terminal (132) so that a protruding rod (322) of the current collector plate (300) can pass through it. Accordingly, the external load and the electrode assembly (200) can be electrically connected to each other via the electrode terminal (132) and the current collector plate (300).

[0087] FIG. 5 is a perspective view showing an electrode terminal illustrated in FIG. 4 according to one embodiment of the present disclosure.

[0088] Referring to FIG. 5, the electrode terminal (132) includes an upper flange (132a) and a lower flange (132b) and a connecting cylinder (132c) that connects the upper flange (132a) and the lower flange (132b) to each other along the axial direction (z), and can be coupled to the bottom plate (110) together with a terminal insulator (131).

[0089] The upper flange (132a) may be positioned to be exposed on the outside of the receiving can (100) and may cover the first terminal surface (131a) of the terminal insulator (131) adjacent to the outer surface (111) of the bottom plate (110). Accordingly, the upper surface (US), which is the exposed surface of the upper flange (132a), is positioned to be exposed to the outside. At this time, the upper flange (132a) may be positioned to cover all or part of the first terminal surface (131a).

[0090] In contrast, the lower flange (132b) may be positioned inside the receiving can (100) to cover the second terminal surface (131b), which is the surface of the terminal insulator (131) adjacent to the inner surface (112) of the bottom plate (110). Accordingly, the lower surface (LS), which is the exposed surface of the lower flange (132b), is positioned inside the receiving space (S) to face the collector plate (300). Like the upper flange (132a), the lower flange (132b) may be positioned to cover all or part of the second terminal surface (131b).

[0091] The upper flange (132a) and the lower flange (132b) each have a disk shape having a terminal hole (TH) and can be respectively arranged on the first and second terminal surfaces (131a, 132a) of the terminal insulator (131). Accordingly, the distance along the axial direction (z) between the upper surface (US) and the lower surface (LS) can be provided as the terminal thickness (T) of the electrode terminal (132).

[0092] The connecting cylinder (132c) may be provided as a hollow cylinder that covers the inner surface of the insulating hole (IH) and is connected to the upper flange (132a) and the lower flange (132b), respectively. Accordingly, the inner hollow portion of the connecting cylinder (132c) may be provided as a terminal hole (TH) having a smaller size than the insulating hole (IH).

[0093] Accordingly, the upper flange (132a) located on the outside of the receiving can (100) and the lower flange (132b) located on the inside can be integrally connected by a connecting cylinder (132c) penetrating the insulating hole (IH).

[0094] The electrode terminal (132) may be composed of a metal material with excellent conductivity. In the present embodiment, the electrode terminal (132) functions as a positive terminal and may therefore be composed of aluminum. However, this is merely exemplary, and it is apparent that the electrode terminal (132) may be composed of various materials depending on the polarity.

[0095] In particular, the terminal insulator (131) and the electrode terminal (132) can be joined to the base plate (110) by a riveting process. For example, the terminal insulator (131) can be formed by forming a terminal insulating bulk (not shown) on the base plate (110) so as to be inserted into the through hole (PH) and then joining it to the base plate (110) by a riveting process. In addition, the electrode terminal (132) can be formed by placing the electrode terminal mother body on the terminal insulator (131) so as to pass through the insulating hole (IH) and then joining it to the terminal insulator (131) by a riveting process. Therefore, the electrode terminal (132) can be provided as a rivet terminal.

[0096] Alternatively, a preform (not shown) in which a terminal insulator (131) and an electrode terminal (132) are combined may be formed on a base plate (110) so as to be inserted into a through hole (PH), and then a riveting process may be performed to form the terminal insulator (131) and the electrode terminal (132) as one body.

[0097] Referring again to FIGS. 1 to 4, the electrode assembly (200) may be provided in a cylindrical shape, which is arranged in a receiving can (100) to store electrochemical energy and has a core cavity (CV) located in the center and a predetermined height along the axial direction (z). The electrode assembly (200) may be electrically connected to an electrode terminal (132) by a current collector (300) described below.

[0098] In particular, in the present embodiment, the electrode assembly (200) is provided in a tab-less structure using a non-conductive portion as a connection tab without a separate connection tab.

[0099] Fig. 6 is a perspective view showing a plate laminate structure in which the electrode assembly shown in Fig. 3 is unfolded, and Fig. 7 is an exploded perspective view showing the plate laminate structure shown in Fig. 6.

[0100] Referring to FIGS. 6 and 7, the electrode assembly (200) can be provided as a jelly-roll structure in which a first electrode plate (210) and a second electrode plate (220) are laminated with a separator (230) interposed therebetween, and a plate laminate structure (200a) is wound around a core shaft to form a cylindrical shape, and then the core shaft is removed to provide a core cavity (CV) in the center.

[0101] The first electrode plate (210) may be configured with a holding portion (211) on which a first active material layer is coated on a first electrode sheet provided in the shape of a strap having a constant width and length, and a non-coated portion (212) on which the first active material layer is not coated. The first non-coated portion (212) may be divided into a plurality of first divided pieces (212p) having a set interval by a notching process and may be provided as a connection tab with a collector plate (300) described later. That is, the first electrode plate (210) may be directly joined with the first divided pieces (212p) as the non-coated portion (212) and the collector plate (300) described later, thereby connecting the collector plate (300) and the electrode assembly (200) without a separate connection tab.

[0102] The second electrode plate (220) may be configured with a holding portion (221) on which a second active material layer is coated on a second electrode sheet provided in the shape of a strap having a constant width and length, and a non-coated portion (222) on which the second active material layer is not coated. The second non-coated portion (222) may be divided into a plurality of second divided pieces (222p) having a set interval by a notching process and may be provided as a connection tab with an additional current collector (350) to be described later. That is, the second electrode plate (220) may be directly bonded between the second divided pieces (222p) which are the non-coated portion (222) and the additional current collector (350), thereby electrically connecting the additional current collector (350) and the electrode assembly (200) without a separate connection tab.

[0103] The first active material layer and the second active material layer are configured to have different electrical polarities, so that the first electrode plate (210) and the second electrode plate (220) have different electrical polarities. In the present embodiment, the first electrode plate (210) may be provided as a positive electrode plate coated with a positive electrode active material layer, and the second electrode plate (220) may be provided as a negative electrode plate coated with a negative electrode active material layer.

[0104] For example, the first active material layer may be composed of a positive electrode active material layer including a lithium metal compound capable of performing a reduction reaction that combines lithium ions and electrons, and the second active material layer may be composed of a negative electrode active material layer including a lithium metal compound capable of performing an oxidation reaction that generates lithium ions and electrons.

[0105] The first split piece (212p) and the second split piece (222p) can be bent toward the core of the jelly-roll structure along the radial direction (r) at both ends of the cylindrical electrode assembly (200) to provide surfaces that are substantially perpendicular to the axial direction (z). Accordingly, the first split piece (212p) and the second split piece (222p) can be provided as the first notching tab (T1) and the second notching tab (T2) of the electrode assembly (200), respectively, so that the electrode assembly (200) can be provided with a tab-less structure that does not have a separate connection tab.

[0106] In the present embodiment, the first notched tab (T1) may be provided as a positive tab and the second notched tab (T2) may be provided as a negative tab. However, this is not necessarily limited to this, and it is obvious that the first notched tab (T1) may be provided as a negative tab and the second notched tab (T2) may be provided as a positive tab.

[0107] Accordingly, the first electrode plate (210) of the electrode assembly (200) can be connected to the electrode terminal (132) through the first notched tab (T1) and the collector plate (300), and the second electrode plate (220) of the electrode assembly (200) can be connected to the receiving can (100) through the second notched tab (T2) and the additional collector plate (350).

[0108] For example, the electrode terminal (132) may be provided as a positive terminal for electrically connecting an external load to the electrode assembly, and the receiving can (100) may be provided as a negative terminal of an electric circuit including a secondary battery (500). Accordingly, the secondary battery (500) according to one embodiment of the present disclosure may be provided as a tab-less battery having a cylindrical tab-less type electrode assembly (200).

[0109] Referring again to FIGS. 1 to 4, a current collector plate (300) and an additional current collector plate (350) can be joined to both ends of the electrode assembly (200) to electrically connect the electrode assembly (200) to the outside.

[0110] For example, the current collector plate (300) has a first tab current collector (330) that is connected to the first notched tab (T1) and a terminal current collector (320) that is connected to the electrode terminal (132), and can electrically connect a terminal unit (130) that penetrates the bottom plate (110) and an electrode assembly (200) accommodated inside the receiving can (100).

[0111] In particular, the terminal collector (320) has a protruding rod (322) that penetrates the terminal hole (TH) and has a chamfered surface (322a) arranged in the edge region, so that the electrode terminal (132) and the collector plate (300) can be joined by terminal welding between the protruding rod (322) exposed through the terminal hole (TH) from the outside of the receiving can (100) and the electrode terminal (132).

[0112] At this time, the welding area where terminal welding is performed is expanded by the chamfered surface (322a) provided on the protruding rod (322), thereby preventing the welding bead (WB) from protruding to the surface of the electrode terminal (132) and the rod surface (RS) of the protruding rod (322).

[0113] The collector plate (300) is described in more detail with reference to FIGS. 8 and 9.

[0114] At this time, an insulating disk (ID) is placed between the collector plate (300) and the bottom plate (110) so that the collector plate (300) connected to the electrode terminal (132) can be electrically separated from the receiving can (100) connected to the additional collector plate (350). Although not shown, the collector plate (300) and the side wall (120) can be electrically separated by an insulating tape.

[0115] For example, the insulating disk (ID) may be provided in the shape of a hollow disk that covers the inner surface (112) of the bottom plate (110) and surrounds the terminal unit (130). Accordingly, the terminal unit (130) disposed on the inner surface (112) of the bottom plate (110) is inserted into and surrounded by the hollow portion of the insulating disk (ID), and the protruding rod (322) penetrating the terminal hole (TH) is also positioned in the hollow central portion of the insulating disk (ID).

[0116] Accordingly, the collector plate (300) is electrically separated from the receiving can (100) and fixed to the electrode terminal (132) and the first notched tab (T1), and the external load is connected to the electrode terminal (132) and electrically connected to the electrode assembly (200) through the collector plate (300) and the first notched tab (T1).

[0117] FIG. 8 is a perspective view showing a collector plate arranged at one end of the electrode assembly illustrated in FIG. 3 according to one embodiment of the present disclosure, and FIG. 9 is a cross-sectional view of the collector plate illustrated in FIG. 8 taken along line II-II'.

[0118] Referring to FIGS. 8 to 10, the current collector (300) may include a frame ring (310) extending along the end circumference of the cylindrical electrode assembly (200), a terminal current collector (320) that is coupled to the inside of the frame ring (310) and extends in the shape of a strap having a predetermined width to be connected to the electrode terminal (132), and a first tab current collector (330) that is connected to the first notched tab (T1).

[0119] In particular, the terminal collector (320) may be provided with a protruding rod (322) that extends upward from the center of the frame ring (310) and is inserted into the terminal hole (TH) and has a chamfered surface (322a) arranged in the edge region of the terminal end.

[0120] The frame ring (310) can be provided as a support frame that completes the overall shape of the current collector plate (300) and supports the terminal current collector (320) and the first tab current collector (330) arranged inside.

[0121] In the present embodiment, the frame ring (310) completes the overall shape of the collector plate (300) and is integrally connected to the terminal collector (320) and the first tab collector (330) that are arranged along the circumference of the cylindrical electrode assembly (200) and extend along the radial direction (r).

[0122] The terminal collector (320) includes at least one first collector strap (321) that has a constant width from the inside of the frame ring (310) and extends through the ring center (RC), which is the center of the frame ring (310), and corresponds to the diameter of the frame ring (310), and the first tab collector (330) may include a plurality of second collector straps (331) that have a constant width from the inside of the frame ring (310) and are arranged toward the ring center (RC).

[0123] In the present embodiment, the terminal collector (320) is configured with a pair of diameters spaced apart by 90° so that four first collector straps (321) can be spaced apart by 90° along the circumferential direction (θ) from the ring center (RC).

[0124] Additionally, the second collector strap (331) is arranged to extend along the radial direction (r) between a pair of adjacent first collector straps (321), so that the first collector strap (321) and the second collector strap (331) can be alternately positioned along the circumferential direction (θ) inside the frame ring (310). Accordingly, four second collector straps (331) can be arranged between four first collector straps (321).

[0125] The second collector strap (331) can be welded to the first notched tab (T1), and the first collector strap (321) can be welded to the electrode terminal (132) as described below. Since the first collector strap (321) and the second collector strap (331) are positioned separately from each other, the protruding rod (322) positioned on the second collector strap (331) and the electrode terminal (132) can absorb shape deformation while being welded to each other, thereby increasing welding stability.

[0126] At this time, the frame ring (310), the terminal collector (320), and the first tab collector (330) are formed integrally with each other, so that the terminal collector (320) and the first tab collector (330) can be positioned at the same level. Accordingly, the second tab collector (351) is welded to the first notched tab (T1), so that the collector plate (300) can be fixed to one end of the electrode assembly (200) by welding.

[0127] For example, the protruding rod (322) may be provided as a column structure that protrudes upward from the first collector strap (321) in the ring center (RC) region to have a predetermined height (h). Accordingly, when the electrode assembly (200) is accommodated in the accommodation space (S), the protruding rod (322) is arranged to penetrate the terminal hole (TH).

[0128] At this time, the protruding rod (322) can be set to a protruding height (h) so that the rod surface (RS) exposed to the outside through the terminal hole (TH) forms the same plane as the surface of the upper flange (132a).

[0129] Additionally, a chamfer may be performed on the edge area of ​​the protruding rod (322) to provide a chamfered surface (322a) positioned inclined with respect to the rod surface (RS) of the protruding rod (322). The chamfered surface (322a) may expand the gap between the connecting cylinder (132c) defining the terminal hole (TH) and the protruding rod (322), thereby expanding the welding area during welding to join the protruding rod (322) and the electrode terminal (132).

[0130] Accordingly, the welding bead (WB) generated during terminal welding can be set to be positioned lower than the rod surface (RS) of the protruding rod (322) and the surface of the upper flange (132a).

[0131] A plurality of secondary batteries (500) can be configured as a single operating battery module (1000) by a bus bar (700) connected to a load surface (RS) and an upper surface (US). At this time, the welding bead (WB) can be set to be lower than the load surface (RS) and the upper surface (US), thereby increasing the connection stability between the bus bar (700) and the secondary battery (500).

[0132] In the present embodiment, the current collector plate (300) may be formed of a low-resistance metal, such as aluminum, to reduce the connection resistance with the first notched tab (T1) provided as the positive tab. Preferably, the current collector plate (300) may be formed of the same conductive metal as the electrode terminal (132).

[0133] Referring again to FIGS. 1 to 4, an additional collector plate (350) may be bonded to the second notched tab (T2) and the receiving can (100) to provide grounding of the secondary battery (500).

[0134] For example, the additional collector plate (350) is configured to have a step along the axial direction (z), so that it can be simultaneously joined to the second notching tab (T2) and the beading portion (B) spaced apart from the second notching tab (T2) by a certain distance along the axial direction (z). Accordingly, the second notching tab (T2) can be electrically connected to the receiving can (100) by the additional collector plate (350).

[0135] FIG. 11 is a perspective view showing an additional collector plate arranged at the other end of the electrode assembly illustrated in FIG. 3 according to one embodiment of the present disclosure.

[0136] Referring to FIG. 11, the additional collector plate (350) may include a second tab collector (351) having an additional through hole (APH) and welded to a second notched tab (T2) and a can collector (352) positioned so as to be spaced apart from the second tab collector (351) along the axial direction (z) and connected to the receiving can (100).

[0137] The second tab collector (351) may include a collector ring (351a) having an additional through hole (APH) and welded to the center of the second notching tab (T2) and a plurality of lower wings (351b) spaced apart at regular intervals along the circumference of the collector ring (351a) and welded to the periphery of the second notching tab (T2).

[0138] The collector ring (351a) is configured as a flat ring having an additional through hole (APH) communicating with the core cavity (CV) of the electrode assembly (200) and can be welded to the central portion of the electrode assembly (10) adjacent to the core cavity (CV).

[0139] A plurality of lower wings (351b) may be welded to the periphery of the electrode assembly (200) so as to extend from the current collecting ring (351a) in a radial direction (r) and be arranged at regular intervals along the circumferential direction (θ). For example, four lower wings (351b) may be arranged so as to extend from the current collecting ring (351a) at an angle of 90° along the circumferential direction (θ).

[0140] However, this is exemplary, and additional through holes (APH) may be optionally provided. As described above, since the welding tip for terminal welding is not inserted into the core cavity (CV), it is self-evident that the additional collector plate (350) may be formed to cover the core cavity (CV) without the additional through holes (APH).

[0141] The can collector (352) can be positioned to extend from the collector ring (351a) in the radial direction (r) and spaced apart from the axial direction (z) so as to be alternately positioned with a plurality of lower wings (351b).

[0142] In particular, the can collector (352) may include a strap-shaped connecting line (352a) that is connected at an angle so as to be spaced apart from the collector ring (351a) and an upper wing (352b) that is connected to the connecting line (352a) and welded to the beading portion (B) of the receiving can (100).

[0143] The connecting line (352a) extends upwardly and obliquely from the collector ring (351a) between the adjacent lower wings (351b), and the upper wing (352b) arranged at the end of the connecting line (352a) is arranged to be spaced apart from the lower wing (351b) along the axial direction (z) between the adjacent lower wings (351b).

[0144] Accordingly, the upper wing (352b) is provided as an arc-shaped connecting plate arranged at regular intervals along the circumferential direction (θ) at the open end (OP) of the receiving can (100) so that it can be welded in a surface contact state with the beading portion (B). At this time, the can welding, which is the welding that joins the upper wing (352b) and the beading portion (B), can be performed after the terminal welding, which is the welding between the electrode terminal (132) and the protruding rod (322), is completed.

[0145] A sealing cap (C) covering the upper wing (352b) can be arranged to seal the receiving space (S) from the outside. Accordingly, leakage of the electrolyte injected into the receiving space (S) can be prevented. The sealing cap (C) is provided in a disk shape corresponding to the shape of the open end (OP), and the peripheral portion is configured to be covered by an insulating cover (IC). Accordingly, the upper wing (32b2) and the sealing cap (C) can be electrically isolated.

[0146] After placing a sealing cap (C) on the upper wing (352b) to electrically insulate it from the upper wing (352b), the side wall (120) of the receiving can (100) can be bent by a crimping process to secure the sealing cap (C) to the open end (OP) of the receiving can (100).

[0147] Although this embodiment discloses a configuration in which the receiving can (100) and the second notched tab (T2) are electrically connected by an additional collector plate (350), it is obvious that the second notched tab (T2) and the receiving can (100) or the second notched tab (T2) and the sealing cap (C) may be directly connected without the additional collector plate (350).

[0148] Referring again to FIGS. 1 to 4, the terminal unit (130) and the collector plate (300) can be welded on the outside of the receiving can (100) by a welding bead (WB) that fills a welding recess (WR) defined by the chamfered surface (322a) and the inner surface of the terminal hole (TH) and is positioned lower than the terminal unit (130).

[0149] That is, the protruding rod (322) and the electrode terminal (132) can be welded by an external welding terminal located outside the receiving can (100) and spaced from the bottom plate (110) rather than an internal welding tip located inside the receiving space (S) passing through the core hollow (CV).

[0150] Accordingly, the welding by-products are generated not inside the core cavity (CV), but outside the electrode terminal (132), thereby preventing damage to the electrode assembly (200) caused by the welding by-products.

[0151] Fig. 12 is a drawing showing in detail the joint structure of the electrode terminal and the protruding rod included in the secondary battery illustrated in Fig. 2.

[0152] Referring to FIG. 12, an electrode assembly (200) having a current collector (300) welded to a first notching tab (T1) is accommodated in a receiving can (100) such that a protruding rod (322) is inserted into a terminal hole (TH), so that the protruding rod (322) and the electrode terminal (132) can be joined to each other by terminal welding performed on the outside of the receiving can (100).

[0153] In particular, the contact stability with the bus bar (700) in the battery module (1000 in FIG. 15) including the secondary battery (500) can be improved by setting the load surface (RS) of the protruding load (322) penetrating the terminal hole (TH) to be positioned at the same level as the upper surface (US) of the electrode terminal (132).

[0154] Accordingly, the protruding rod (322) can protrude by a protrusion height (h) corresponding to the distance along the axial direction (z) from the first collector strap (321) to the upper surface (US) of the electrode terminal (132) and the back surface of the insulating disk (ID).

[0155] Since the electrode assembly (200) is positioned so that the first collector strap (321) and the insulating disk (ID) are in contact with each other inside the receiving can (100), the protrusion height (h) may vary depending on the thickness of the insulating disk (ID) and the terminal thickness (T).

[0156] As shown in Fig. 12, when the insulating disk (ID) has a thickness such that its back surface is positioned at a level lower than the lower surface (LS) of the electrode terminal (132), the first current collecting strap (321) is positioned spaced apart from the lower surface (LS) of the electrode terminal (132) by a predetermined insulating gap (G), and the protrusion height (h) increases by the insulating gap (G).

[0157] In contrast, when the insulating disk (ID) is positioned at the same level as the back surface and the lower surface (LS) of the electrode terminal (132), the first collector strap (321) can be in contact with the lower surface (LS) of the electrode terminal (132) and the back surface of the insulating disk (ID) at the same time, and the protrusion height (h) can be set to be equal to the thickness of the electrode terminal (132). That is, the protrusion height (h) can be set to the gap between the upper surface (US) and the lower surface (LS) of the electrode terminal (132).

[0158] Accordingly, the protrusion height (h) may have the terminal thickness (T) as the minimum value and the sum of the terminal thickness (T) and the insulation gap (G) as the maximum value. In the present embodiment, the insulation gap (G) may be set in a range of about 0 mm to 1.0 mm, and the terminal thickness (T) of the electrode terminal (132) may have a range of about 3.0 mm to 3.5 mm. Accordingly, the protrusion height (h) may have a range of about 3.0 mm to 4.5 mm. The insulation gap (G) and the terminal thickness (T) may be appropriately set according to the height and diameter of the secondary battery (500).

[0159] For example, the protruding rod (322) may be inserted with an appropriate fit tolerance to maintain the relative position of the protruding rod (322) with respect to the electrode terminal (132) while the terminal welding described below is performed. Accordingly, the protruding rod (322) may be positioned within the terminal hole (TH) with a gap (tg) corresponding to the fit tolerance with respect to the electrode terminal (132).

[0160] After the electrode assembly (200) is accommodated in the receiving can (100), the receiving can (100) is inverted so that the bottom plate (110) is positioned upward, and then terminal welding is performed by a welding module (WM) positioned on the top of the bottom plate (110). At this time, the protruding rod (322) can be inserted into the terminal hole (TH) by, for example, a forced fit or an intermediate fit, so as to stably maintain the position of the protruding rod (322) inside the terminal hole (TH).

[0161] Accordingly, even if a separate fixing member for fixing the position of the electrode assembly (200) into the core cavity (CV) is not inserted, the position of the protruding rod (322) can be stably maintained while terminal welding is in progress. Accordingly, the energy density of the secondary battery (500) can be increased by configuring the core cavity to have the smallest possible size.

[0162] In the present embodiment, the protruding rod (322) can be set to have a diameter so as to have a gap (tg) of about 0.01 mm to 0.02 mm based on the size of the terminal hole (TH).

[0163] In addition, a chamfered surface (322a) is arranged on the edge area of ​​the protruding rod (322), so that a welding recess (WR in FIG. 13) of a relatively wide area can be arranged in a ring shape on the upper end of the protruding rod (322).

[0164] Fig. 13 is a perspective view showing the connection relationship between the electrode terminal and the protruding rod before performing terminal welding, and Fig. 14 is a cross-sectional view showing the welding recess shown in Fig. 13 in an enlarged manner.

[0165] Referring to FIGS. 13 and 14, the chamfered surface (322a) of the protruding rod (322) is arranged to be inclined downward along the axial direction (z) from the rod surface (RS), so that a welding recess (WR) having a ring shape is provided, which is defined by the inner surface of the connecting cylinder (132c) provided to the inner surface of the terminal hole (TH) and the chamfered surface (322a) and extends along the circumferential direction (θ).

[0166] The weld recess (WR) decreases in size as it progresses downward from the load surface (RS) in the axial direction (z), having a maximum size in the upper region adjacent to the load surface (RS) and a minimum size corresponding to the gap (tg) in the lower region.

[0167] In the present embodiment, terminal welding between the protruding rod (322) and the electrode terminal (132) can be performed by a laser (L) irradiated from a laser gun (LG) located on the upper part of the bottom plate (110) into the welding recess (WR).

[0168] In particular, the terminal welding laser (L1) irradiated into the welding recess (WR) welds the connecting cylinder (132c) and the protruding rod (322) from the lower portion of the welding recess (WR) rather than the rod surface (RS) or upper surface (US), thereby forming a welding bead (WB) that grows upward. The welding bead (WB) may be provided in a ring shape surrounding the upper portion of the protruding rod (322) depending on the shape of the welding recess (WR).

[0169] At this time, the characteristics of the terminal welding can be adjusted so that the upper surface of the welding bead (WB) is positioned at a level lower than the load surface (RS) and the upper surface (US), thereby adjusting the welding bead (WB) to be positioned inside the welding recess (WR). Accordingly, the welding bead (WB) can be prevented from protruding toward the load surface (RS) and the upper surface (US) of the electrode terminal (132).

[0170] In the present embodiment, the chamfer angle (θ), which is the angle formed by the chamfer surface (322a) with the rod surface (RS), may be set to have a range of about 60° to 75°. If the chamfer angle (θ) is less than 60°, the depth (D) of the welding recess (WR) is not deep enough, so that the welding bead (WB) protrudes from the upper surface (US) of the electrode terminal (132) or the rod surface (RS), and if the chamfer angle (θ) is greater than 75°, the depth (D) of the welding recess (WR) is formed too deep, so that the welding bead (WB) may be supplied to the first current collecting strap (321). Accordingly, while terminal welding is in progress, welding by-products may diffuse into the interior of the receiving can (100), which may cause damage to the electrode assembly (200). Therefore, it is preferable to set the chamfer angle (θ) of the protruding rod (322) to have a range of about 60° to 75°.

[0171] In the present embodiment, the welding recess (WR) defined by the chamfered surface (322a) may be provided as a space having a depth (D) of about 0.4 mm to about 0.6 mm along the axial direction (z) from the load surface (RS) and a maximum width (W) of about 0.2 mm along the radial direction (r), and a cross-section with respect to the axial direction (z) forming a right-angled triangle.

[0172] The protruding rod (322) inside the terminal hole (TH) is positioned so as to have a gap (tg) with the electrode terminal (132), so that the welding area is set by the welding recess (WR) and the gap (tg). Since the welding area is positioned to be widest at the top adjacent to the rod surface (RS), the possibility of welding on the upper surface (US) or the rod surface (RS) can be minimized.

[0173] When welding is performed along the welding area, welding is performed from the lower portion of the welding area, so that the weld bead (WB) joining the inner surface of the connecting cylinder (132c) and the upper flange (132a) and the outer surface of the protruding rod (322) grows upward. Accordingly, the weld bead (WB) may include a bead leg (B1) extending upward along the gap (tg) and a bead body (B2) filling the welding recess (WR).

[0174] At this time, the gap (tg) is configured as a fitting tolerance for fixing the protruding rod (322) inside the terminal hole (TH), and is thus filled by the bead leg (B1) downwards for a certain length while the terminal welding is in progress. However, the lower end of the bead leg (B1) is set so as not to go beyond the terminal hole (TH) and is positioned so as to be spaced apart from the first current collecting strap (321). In addition, the bead body (B2) is positioned so as to be accommodated inside the welding recess (WR) by setting the welding conditions so that the upper surface is positioned lower than the upper surface (US) or the rod surface (RS).

[0175] Accordingly, the welding bead (WB) is positioned to fill the gap (tg) at the top of the first current collecting strap (321), thereby suppressing the inflow of welding by-products into the receiving can (100) and allowing them to be received inside the welding recess (WR), thereby maintaining the upper surface (US) and the rod surface (RS) smooth.

[0176] In the present embodiment, the gap (tg) may be in the range of about 0.01 mm to 0.02 mm, and the weld bead (WB) may be configured to have a length corresponding to about 40% to 60% of the terminal thickness (T). If the length of the weld bead (WB) is less than 40% of the terminal thickness (T), the contact area between the electrode terminal (132) and the protruding rod (322) may not be sufficient, which may cause welding defects or bonding defects. In addition, if the length of the weld bead (WB) is greater than 60% of the terminal thickness (T), the bead leg (B1) may grow too deeply downward, causing welding byproducts to flow into the first current collecting strap (321) while terminal welding is in progress, which may cause damage to the electrode assembly (200).

[0177] In the present embodiment, the terminal thickness (T) may range from about 3.0 mm to 3.3 mm, and the welding bead (WB) may range from about 1.2 mm to 1.9 mm. However, this is exemplary, and it is obvious that the thickness may be set in various ways depending on the form factor of the secondary battery (500).

[0178] According to the secondary battery (500) as described above, the electrode terminal (132) and the current collector plate (300) are terminal-welded on the outside of the receiving can (100) and the welding bead (WB) is embedded in the inside of the welding recess (WR), thereby preventing the welding bead (WB) from being exposed to the outer surface of the secondary battery (500). Accordingly, welding damage caused by welding byproducts can be prevented and the contact stability of the electrode terminal (132) and the bus bar can be improved.

[0179] In particular, since terminal welding is performed outside rather than inside the receiving can (100), there is no need to insert a welding tip for performing terminal welding into the core cavity (CV) of the electrode assembly (200), and thus the size of the core cavity (CV) can be minimized regardless of terminal welding. Accordingly, the energy density of the electrode assembly (200) can be increased.

[0180] Fig. 15 is a perspective view showing a battery module having the secondary battery shown in Fig. 1, and Fig. 16 is a cross-sectional view showing the contact state between the secondary battery shown in Fig. 15 and the bus bar.

[0181] Referring to FIGS. 15 and 16, a battery module (1000) according to one embodiment of the present disclosure may include a case (600) having a plurality of battery holders (610), a plurality of secondary batteries (500) accommodated in the case (600), and a bus bar (700) to which a charge and discharge current is applied.

[0182] As an example, the secondary battery (500) constituting the battery module (1000) may include a cylindrical tab-less battery. In the present embodiment, the secondary battery (500) has substantially the same configuration as the secondary battery (500) described with reference to FIGS. 1 to 14 . Accordingly, in FIGS. 15 and 16 , the same reference numerals are used for the same components as in FIGS. 1 to 14 , and further detailed descriptions are omitted.

[0183] A secondary battery (500) may include a receiving can (100), an electrode assembly (200), and a current collector (300). The receiving can (100) may include a bottom plate (110) having a through hole (PH), and a terminal unit (130) that is disposed on the bottom plate (110) to be inserted into the through hole (PH), has a terminal hole (TH) in the center, and is electrically connected to a bus bar (700). The electrode assembly (200) may be provided in a cylindrical shape that is received in the receiving can (100) to store electrochemical energy and has a core cavity (CV) in the center. The current collector (300) may be joined to be electrically connected to one end of the electrode assembly (200), is exposed to the outside of the receiving can (100) by penetrating the terminal hole (TH), and may have a chamfered surface (322a) along the circumference of the terminal hole (TH).

[0184] At this time, the terminal unit (130) and the collector plate (300) can be joined by a welding bead (WB) positioned inside a welding recess (WR) defined by the chamfered surface (322a) and the inner surface of the terminal hole (TH) and positioned lower than the terminal unit (130).

[0185] The terminal unit (130) may include a terminal insulator (131) that is inserted into the through hole (PH) to cover the outer surface and inner surface of the bottom plate (110) adjacent to the through hole (PH) and provides an insulating hole (IH) having a size smaller than the through hole (PH), and an electrode terminal (132) that is inserted into the insulating hole (IH) to surround the terminal insulator (131) and provides a terminal hole (TH) having a size smaller than the insulating hole (IH) in the central portion.

[0186] The collector plate (300) can be composed of a frame ring (310), a terminal collector (320) disposed inside the frame ring (310), and a first tab collector (330). The terminal collector (320) has a protruding rod (322) that protrudes upward along the axial direction (z) and is inserted into a terminal hole (TH) and has a chamfered surface (322a) in the edge region. The terminal collector (320) can be connected to an electrode terminal (132), and the first tab collector (330) can be connected to a first notched tab (T1).

[0187] In particular, the electrode terminal (132) includes an upper flange (132a) that covers the outer surface of the terminal insulator (131) and is exposed to the outside, a lower flange (132b) that covers the inner surface of the terminal insulator (131) and is located inside the receiving can (100), and a connecting cylinder (132c) that is connected to the upper flange (132a) and the lower flange (132b) and covers the inner surface of the insulating hole (IH), and the protruding rod (322) can be positioned so that the rod surface (RS) exposed to the outside through the terminal hole (TH) forms the same plane as the upper surface (US) along the radial direction (r).

[0188] As an example, the case (600) has a hexahedral shape and has a plurality of battery holders (610) arranged in a matrix shape to accommodate secondary batteries (500) therein. In the present embodiment, the battery holders (610) may be provided as circular receiving portions to accommodate tab-less batteries having a cylindrical shape.

[0189] For example, the case (600) is made of steel having sufficient strength and rigidity to protect the received secondary battery (500) from external impact and can sufficiently support the bus bar (700) that electrically connects the received secondary battery (500) and the battery management system (not shown) for the module.

[0190] The bus bar (700) may include a conductive line that electrically connects each secondary battery (500) accommodated in the case (600). The bus bar (700) may be connected to a battery management system for a module so that a plurality of secondary batteries (500) accommodated in the case (600) may transmit a charge / discharge signal for a single electrical behavior as a module unit, or may include a signal line or charge / discharge line through which charge / discharge current flows.

[0191] At this time, the bus bar (700) can simultaneously contact the load surface (RS) of the adjacent secondary battery (500) and the upper surface (US) of the upper flange (132a) to increase the stability of contact with the secondary battery (500).

[0192] In particular, the electrode terminal (132) and the protruding rod (322) are welded on the outside of the receiving can (100), but the welding bead (WB) is positioned inside the welding recess (WR) so as not to come into contact with the bus bar (700), thereby preventing the formation of the welding bead (WB) on the upper surface (US) or the rod surface (RS).

[0193] Accordingly, by performing terminal welding on the outside of the receiving can (100), the contact stability between the secondary battery (500) with improved energy density and the bus bar (700) to which the charge and discharge current is applied can be improved, thereby increasing the operational stability of the battery module (1000).

[0194] FIG. 17 is a flowchart showing a method for manufacturing a secondary battery disclosed in FIG. 1 according to one embodiment of the present disclosure, and FIGS. 18 to 23 are process cross-sectional views showing a method for manufacturing a secondary battery illustrated in FIG. 17.

[0195] Referring to FIGS. 17 and 18, a receiving can (100) is formed in which an electrode terminal (132) having a terminal hole (TH) is joined to a bottom plate (110) (step S100).

[0196] The receiving can (100) may be formed in a cylindrical shape made of aluminum or steel and has a bottom plate (110) and side walls (120). A through hole (PH) is arranged in the center of the bottom plate (110), and a terminal unit (130) including an electrode terminal (132) having a terminal insulator (131) and a terminal hole (TH) inside the through hole (PH) is fixed by a rivet connection.

[0197] Accordingly, the receiving space (S) inside the receiving can (100) is defined by the bottom plate (110) and the side wall (120), and the end of the receiving can (100) facing the bottom plate (110) is opened to communicate with the outside, forming a cylinder shape with one end open.

[0198] The terminal insulator (131) can be fixed to the bottom plate (110) by rivet joints so as to cover the outer surface (111) and the inner surface (112) of the bottom plate (110) adjacent to the through hole (PH) and be inserted into the through hole (PH). The terminal insulator (131) has an insulating hole (IH) having a size smaller than the through hole (PH), so that the electrode terminal (132) can be coupled so as to pass through the insulating hole (IH).

[0199] The terminal insulator (131) may be provided as a gasket to electrically separate the bottom plate (110) and the electrode terminal (132) and prevent leakage of the electrolyte stored in the receiving space (S).

[0200] The electrode terminal (132) is electrically isolated from the base plate (110) by a terminal insulator (131) and is fixed to the terminal insulator (131) by a rivet joint through a through hole (PH). A terminal hole (TH) is provided in the center of the electrode terminal (132) to communicate with the receiving space (S) and the outside.

[0201] The electrode terminal (132) is inserted into the insulating hole (IH) so as to surround the terminal insulator (131), and a terminal hole (TH) having a size smaller than the insulating hole (IH) is provided in the center. In the present embodiment, the electrode terminal (132) may include an upper flange (132a) that covers the first terminal surface (131a) which is the outer surface of the terminal insulator (131) and is exposed to the outside, a lower flange (132b) that covers the second terminal surface (131b) which is the inner surface of the terminal insulator (131) and is located inside the receiving can (100), and a connecting cylinder (132c) that is connected to the upper flange (132a) and the lower flange (132b) and covers the inner surface of the insulating hole (IH).

[0202] An insulating disk (ID) is formed on the inner surface (112) of the base plate (110). For example, the insulating disk (ID) is formed in a hollow disk shape having an opening surrounding the terminal unit (130), so that the terminal unit (130) is exposed toward the receiving space (S) and the inner surface (112) is covered by the insulating disk (ID).

[0203] The insulating disk (ID) can extend to the joining area of ​​the side wall (120) and the bottom plate (110) to block the current collector plate (300) of the electrode assembly (200) accommodated in the receiving can (100) from being electrically connected to the bottom plate (110) in a subsequent process.

[0204] In the present embodiment, the insulating disk (ID) is made of a polymer with excellent electrical insulation properties and can be molded onto the inner surface (112) of the bottom plate (110) by an injection molding process.

[0205] Referring to FIGS. 17 and 19, an electrode assembly is formed by joining a current collector plate (300) and an additional current collector plate (350) having a protruding rod (322) having a chamfered surface (322a) arranged in an edge region (step S200).

[0206] The electrode assembly (200) is formed in a cylindrical shape that stores electrochemical energy and has a core cavity (CV) in the center. In particular, the split non-conductive portions arranged at both ends of the electrode assembly (200) are bent to form a first notching tab (T1) and a second notching tab (T2), respectively, to have a tab-less structure. Since the electrode assembly (200) has the same structure as the electrode assembly (200) described with reference to FIG. 3, further detailed description is omitted.

[0207] The current collector plate (300) can be formed so that the first tab current collector (330) that is joined by welding to the first notched tab (T1) inside the frame ring (310) and the terminal current collector (320) that is joined to the electrode terminal (132) are integrally connected.

[0208] At this time, the terminal collector (320) is formed of four first collector straps (321) connected to the inside of the frame ring (310) so as to be spaced apart by 90° along the circumferential direction (θ), and the first tab collector (330) can be connected to the inside of the frame ring (310) so as to be alternately positioned with the first collector straps (321) along the circumferential direction (θ). At this time, the second collector strap (331) can be formed so as to be separated from the first collector strap (321) at the center of the frame ring (310).

[0209] A protruding rod (322) protruding upward from the center of the first collector strap (321) and having a chamfered surface (322a) at the edge area of ​​the terminal end can be formed.

[0210] Accordingly, the collector plate (300) is formed to have a plurality of first and second collector straps (321, 331) extending alternately along the radial direction (r) from the inside of the frame ring (310) and a protruding rod (322) protruding upward from the center of the first collector strap (321).

[0211] However, this is exemplary, and it is obvious that the collector plate (300) can have various joining structures as well as the collector strap structure as long as it supports the protruding rod (322) and can be easily joined to the first notched tab (T1).

[0212] Thereafter, a chamfering process may be performed on the edge of the protruding rod (322) to form a chamfered surface (322a). For example, the chamfering process may be performed to have a chamfering angle (θ) of about 60° to 75° with respect to the rod surface (RS) of the protruding rod (322), thereby forming the chamfered surface (322a).

[0213] Next, an additional collector plate (350) is formed, which has a second tab collector (351) and a can collector (352) connected to the second tab collector (351) so as to be spaced apart from each other along the axial direction (z). The second tab collector (351) and the can collector (352) may be formed integrally with each other.

[0214] The current collector plate (300) and the additional current collector plate (350) can be fixed to the first notched tab (T1) and the second notched tab (T2) of the electrode assembly (200), respectively, by welding. For example, the current collector plate (300) and the additional current collector plate (350) and the first and second notched tabs (T1, T2) can be welded by a laser (L).

[0215] At this time, since the first collector strap (321) is formed to be separated from the second collector strap (331), even if the shape and position of the first collector strap (321) are deformed by the terminal welding process for joining the electrode terminal (132) and the protruding rod (322), the shape and position of the entire collector plate (300) can be maintained constant.

[0216] The current collector plate (300) and the additional current collector plate (350) have substantially the same structure as the current collector plate (300) and the additional current collector plate (350) described with reference to FIGS. 8 to 11, so further detailed description is omitted.

[0217] Referring to FIGS. 17 and 20, the electrode assembly (200) is accommodated in the receiving can (100) such that the protruding rod (322) penetrates the terminal hole (TH) (step S300). Accordingly, a welding recess (WR) defined by a chamfered surface (322a) along the circumference of the terminal hole (TH) and an inner surface of the terminal hole (TH) is formed.

[0218] For example, an electrode assembly (200) in which a collector plate (300) and an additional collector plate (350) are welded is transferred and inserted into a receiving can (100) through an open end (OP). At this time, the electrode assembly (200) can be inserted so that the protruding rod (322) of the collector plate (300) penetrates the terminal hole (TH) of the electrode terminal (132) arranged on the bottom plate (110).

[0219] The first collector strap (321) of the collector plate (300) and the insulating disk (ID) are in contact, and the protruding rod (322) protruding from the first collector strap (321) can be positioned so that the upper surface (US) of the upper flange (132a) and the rod surface (RS) are at the same level as each other by penetrating the terminal hole (TH).

[0220] At this time, the protruding rod (322) can be inserted into the terminal hole (TH) by an intermediate fit or a forced fit with the connecting cylinder (132c) so as to have a gap (tg) corresponding to the fit tolerance.

[0221] Accordingly, a welding recess (WR) communicating with a gap (tg) may be provided between the connecting cylinder (132c) and the chamfered surface (322a) of the protruding rod (322). The welding recess (WR) may be provided as a welding area for welding the protruding rod (322) and the electrode terminal (132) in a subsequent process.

[0222] Referring to FIG. 17 and FIG. 21, by welding the current collector (300) and the terminal unit (130) on the outside of the receiving can (100) (step S400), a welding bead (WB) that integrally joins the current collector (300) and the terminal unit (130) can be formed inside the welding recess (WR) and the gap (tg).

[0223] For example, a welding module (WM) equipped with a laser gun (LG) is placed on the upper portion of a bottom plate (110) and a terminal welding laser (L1) is irradiated along a welding recess (WR) to weld an electrode terminal (132) and a protruding rod (322). Accordingly, a spare battery (500a) with terminal welding completed can be formed on the bottom plate (110) of the receiving can (100).

[0224] At this time, the welding recess (WR) has a size wider than the gap (tg) due to the chamfered surface (322a) of the protruding rod (322), so that the focus of the terminal welding laser (L1) can be easily set to the welding area. The terminal welding laser (L1) is irradiated to the relatively wide welding area, so that it can be suppressed from being irradiated to the upper surface (US) of the electrode terminal (132) or the rod surface (RS) of the protruding rod (322).

[0225] When the terminal welding laser (L1) is irradiated, a welding bead (WB) is formed in the adjacent area of ​​the electrode terminal (132) and the protruding rod (322), thereby joining the electrode terminal (132) and the protruding rod (322) as one body. At this time, the terminal welding laser (L1) forms a welding bead (WB) from the gap (tg) below the welding recess (WR) toward the welding recess (WR).

[0226] The welding process conditions can be adjusted so that the upper end of the weld bead (WB) is positioned lower than the upper surface (US) or the rod surface (RS) by adjusting the welding process conditions so that the weld bead (WB) is formed inside the welding recess (WR). Accordingly, the weld bead (WB) can be formed by a bead body (B2) accommodated in the welding recess (WR) and a bead leg (B1) extending downward along a gap (tg) from the bead body (B2).

[0227] For example, a weld bead (WB) can be formed to have a length ranging from about 40% to about 60% of the terminal thickness (T). The length of the weld bead (WB) can be defined as the distance between the top and bottom along the axial direction (z).

[0228] The lower end of the welding bead (WB) can be adjusted to have a sufficient distance from the upper joining strap (321) to prevent welding by-products generated during the process of welding the electrode terminal (132) and the protruding rod (322) from flowing into the interior of the receiving space (S).

[0229] In addition, since the terminal welding between the electrode terminal (132) and the protruding rod (322) is performed outside the receiving can (100), there is no need for a welding tip (e.g., a laser gun (LG)) for terminal welding to be placed in the core cavity (CV) of the electrode assembly (200). Accordingly, the core cavity (CV) can be minimized regardless of the size of the welding tip, thereby increasing the energy density of the electrode assembly (200).

[0230] In this embodiment, a single laser gun (LG) is arranged in the welding module (WM) and starts irradiating a laser (L1) for terminal welding while rotating along a ring-shaped welding recess (WR), but it is obvious that terminal welding can also be performed simultaneously by at least one pair of laser guns (LG) arranged symmetrically to each other.

[0231] Referring to FIG. 17 and FIG. 22, when terminal welding is completed, can welding can be performed to join the open end (OP) of the receiving can (100) and the additional collector plate (350) (step S500).

[0232] For example, a beading portion (B) having a surface parallel to the axial direction (z) can be formed by partially recessing the side wall (120) of the receiving can (100) at the open end (OP) of the spare battery (500a) on which terminal welding has been completed. Accordingly, the upper wing (352b) comes into surface contact with the beading portion (B).

[0233] After the spare battery (500a) in which the beading portion (B) and the upper wing (32b2) are in contact with each other is accommodated in a welding turn table (not shown), the welding turn table is rotated to supply the spare battery (500a) to the welding standby area, and the spare battery (500a) is raised in the welding standby area to perform can welding.

[0234] A can welding device (WA) is inserted into the interior of the open end (OP) to pressurize the upper wing (32b2) of the additional collector plate (350) to the beading portion (B) and then irradiates the can welding laser (L2) to join the upper wing (32b2) to the beading portion (B). The can welding laser (L2) is irradiated to each upper wing (325b2) simultaneously, so that multiple upper wings (352b) can be welded to the beading portion (B) simultaneously.

[0235] Referring to FIGS. 17 and 23, a sealing cap (C) covering the upper portion of the upper wing (32b2) can be placed to seal the interior of the electrode assembly (200) and the receiving can (100) from the outside (step S600). Accordingly, the reserve battery (500a) can be formed into a secondary battery (500).

[0236] For example, a disk-shaped sealing cap (C) having a diameter sufficient to cover the open end (OP) of the receiving can (100) is prepared, and an insulating cover (IC) is formed along the periphery. In the present embodiment, the insulating cover (IC) may be composed of a polymer such as silicone. Accordingly, the upper wing (352b) and the sealing cap (C) may be electrically isolated by the insulating cover (IC).

[0237] After the sealing cap (C) having an insulating cover (IC) is placed on the upper wing (352b) so as to be electrically insulated from the upper wing (352b), the sealing cap (C) can be fixed by a crimping end (CR) bent by a crimping process on the side wall (120) of the receiving can (100).

[0238] Accordingly, the electrode assembly (200) placed in the receiving space (S) is sealed from the outside, and the first notched tab (T1) and the second notched tab (T2) of the electrode assembly (200) can be electrically connected to the electrode terminal (132) and the receiving can (100) through the current collector plate (300) and the additional current collector plate (350), respectively.

[0239] An injection hole (not shown) is arranged in the sealing cap (C) so that an electrolyte can be injected into the interior of a receiving can (100) in which electrode assemblies (200) are arranged. After the electrolyte is injected, the injection hole can be sealed with a stopper to form a spare battery (500a) into a secondary battery (500).

[0240] In this embodiment, an additional collector plate (350) is disclosed having an additional through hole (APH) communicating with the core cavity (CV), but it is apparent that the additional collector plate (350) may be formed to cover the core cavity (CV) without the additional through hole (APH), since the welding tip for terminal welding is not inserted into the core cavity (CV).

[0241] In addition, a configuration is disclosed in which the receiving can (100) and the second notched tab (T2) are electrically connected by an additional collector plate (350), but it is obvious that the second notched tab (T2) and the receiving can (100) or the second notched tab (T2) and the sealing cap (C) may be directly connected without the additional collector plate (350).

[0242] According to the method for manufacturing a secondary battery (500) as described above, the terminal welding for joining the current collector (300) and the electrode terminal (132) can be performed on the outside of the receiving can (100) rather than by a welding tip penetrating the core cavity (CV).

[0243] Accordingly, it is possible to fundamentally prevent defects in the electrode assembly (200) caused by welding by-products generated during terminal welding, and to improve the energy density of the electrode assembly by reducing the size of the core cavity (CV).

[0244] According to the secondary battery (500) as described above, the battery module (1000) including the same, and the manufacturing method (2000) thereof, terminal welding is performed on the outside of the receiving can (100), and compared to conventional terminal welding performed in the core cavity (CV), damage to the electrode assembly (200) due to welding by-products and improvement in energy density due to reduction in the size of the core cavity (CV) can be achieved.

[0245] In particular, the current collector plate (300) is formed to have a protruding rod (322) that penetrates the terminal hole (TH) provided in the electrode terminal (132) and has a ring-shaped chamfered surface on the periphery, thereby providing a welding recess of relatively large size along the periphery of the through hole (PH).

[0246] By adjusting the welding characteristics of the terminal welding, the welding bead (WB) can be formed to be located inside the welding recess (WR) at a level lower than the upper surface (US) of the electrode terminal (132) and the rod surface (RS) of the protruding rod (322).

[0247] Accordingly, by removing the welding bead (WB) from the upper surface (US) and the load surface (RS) of the electrode terminal (132), the contact characteristics of the secondary battery (500) and the bus bar (700) in the battery module (1000) can be improved. Accordingly, the operational stability of the battery module (1000) can be increased.

[0248] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0249] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

[0250] The present disclosure can be used in batteries including energy storage devices and secondary batteries and in the manufacture thereof.

Claims

1. A receiving can having a bottom plate having a through hole and a terminal unit fixed to the bottom plate to be inserted into the through hole and having a terminal hole in the center; A cylindrical electrode assembly accommodated in the above-mentioned receiving can to store electrochemical energy and having a core hollow portion located in the center; and A current collector plate is connected to one end of the electrode assembly so as to be exposed to the outside of the receiving can through the terminal hole and has a chamfered surface along the circumference of the terminal hole, A secondary battery wherein the terminal unit and the current collector plate are positioned inside a welding recess defined by the chamfered surface and the inner surface of the terminal hole and are joined by a welding bead positioned lower than the terminal unit.

2. In claim 1, the terminal unit, A terminal insulator that is inserted into the through hole to cover the outer surface and inner surface of the floor plate adjacent to the through hole and provides an insulating hole having a size smaller than the through hole; and An electrode terminal inserted into the insulating hole to surround the terminal insulator and provided with a terminal hole having a size smaller than the insulating hole in the central portion. A secondary battery, including:

3. In claim 2, the collector plate, a tab collector connected to the above electrode assembly; and A terminal current collector having a protruding rod that protrudes upward along the axis direction in which the virtual central axis of the above-mentioned receiving can extends and is inserted into the terminal hole and has the chamfered surface in the edge region, and is connected to the electrode terminal. A secondary battery, including:

4. In claim 3, the electrode terminal, An upper flange covering a first terminal surface, which is a surface of the terminal insulator adjacent to the outer surface of the base plate, and positioned outside the receiving can; A lower flange located inside the receiving can and covering the second terminal surface, which is the surface of the terminal insulator adjacent to the inner surface of the base plate; and A connecting cylinder connected to the upper flange and the lower flange and covering the side of the insulating hole is included. A secondary battery, wherein the protruding rod is positioned so that the rod surface exposed to the outside through the terminal hole is flush with the surface of the upper flange along the radial direction of the receiving can.

5. In claim 4, A secondary battery, wherein the chamfered surface is arranged to be inclined downward along the axial direction from the load surface, and the welding recess has a ring shape defined by the inner surface of the connecting cylinder provided as the inner surface of the terminal hole and the chamfered surface and extending along the circumferential direction of the receiving can surrounding the axial direction.

6. In claim 5, A secondary battery, wherein the welding recess has a depth of 0.4 mm to 0.6 mm in the axial direction from the load surface and a width of 0.2 mm in the radial direction from the surface of the adjacent connecting cylinder.

7. A secondary battery according to claim 4, wherein the protruding rod is inserted into the terminal hole so as to have a gap with the connecting cylinder, and the welding bead has a bead body positioned in the welding recess and a bead leg extending from the bead body along the gap.

8. In claim 7, A secondary battery, wherein the gap has a range of 0.01 mm to 0.02 mm, and the length of the welding bead has a range of 40% to 60% of the terminal thickness, which is the distance between the outer surface of the upper flange and the inner surface of the lower flange.

9. In claim 4, An insulating disk arranged on the inner surface of the base plate to surround the terminal unit and electrically separate the terminal collector and the base plate. A secondary battery further comprising:

10. In claim 2, A secondary battery, wherein the electrode terminal includes a rivet electrode that penetrates the insulating hole and is fixed to the terminal insulator by a rivet connection.

11. In claim 1, An additional collector plate electrically connected to the other end of the electrode assembly symmetrically positioned along the axial direction and partially connected to the receiving can; and A sealing cap that covers the above additional collector plate and seals it from the outside A secondary battery further comprising:

12. In claim 1, A secondary battery, wherein the above-mentioned receiving can has a cylindrical shape having a height and a diameter, and a form factor, which is a ratio of the diameter to the height, is in the range of 0.4 and 0.

6.

13. A case having multiple battery holders inside; A plurality of secondary batteries stored in the battery holder; and It includes a bus bar that is connected to the plurality of secondary batteries and applies charge and discharge current, Each of the above multiple secondary batteries, A receiving can including a bottom plate having a through hole and a terminal unit disposed on the bottom plate to be inserted into the through hole and having a terminal hole in the center thereof and electrically connected to the bus bar; A cylindrical electrode assembly that is accommodated in the above-mentioned receiving can and stores electrochemical energy and has a core hollow portion in the center; and A current collector plate is bonded to be electrically connected to one end of the electrode assembly, penetrates the terminal hole, is exposed to the outside of the receiving can, and has a chamfered surface along the circumference of the terminal hole. A battery module wherein the terminal unit and the current collector plate are positioned within a welding recess defined by the chamfered surface and the inner surface of the terminal hole and are joined by a welding bead positioned lower than the terminal unit.

14. In claim 13, the terminal unit, A terminal insulator that is inserted into the through hole to cover the outer surface and inner surface of the floor plate adjacent to the through hole and provides an insulating hole having a size smaller than the through hole; and An electrode terminal is included, which is inserted into the insulating hole to surround the terminal insulator and has a terminal hole provided at the center having a size smaller than the insulating hole, The above collector plate, a tab collector connected to the above electrode assembly; and A terminal collector having a protruding rod that protrudes upward along the axial direction in which the virtual central axis of the receiving can extends from the upper part of the central region of the tab collector and is inserted into the terminal hole and has the chamfered surface in the edge region. A battery module comprising:

15. In claim 14, the electrode terminal, An upper flange covering the outer surface of the terminal insulator and exposed to the outside; A lower flange covering the inner surface of the terminal insulator and positioned inside the receiving can; and It includes a connecting cylinder connected to the upper flange and the lower flange and covering the inner surface of the insulating hole, The above protruding rod is positioned so that the rod surface exposed to the outside through the terminal hole forms the same plane as the surface of the upper flange along the radial direction of the receiving can. A battery module wherein the bus bar is in contact with the surface of the load surface and the surface of the upper flange simultaneously, and the welding bead is located at the lower portion of the bus bar.

16. A step of forming a receiving can including a bottom plate having a through hole and a terminal unit disposed on the bottom plate to be inserted into the through hole and having a terminal hole in the center thereof and electrically connected to an external load; A step of forming a cylindrical electrode assembly having a current collector plate and an additional current collector plate joined at both ends and storing electrochemical energy, wherein the current collector plate has a protruding rod with a chamfered surface arranged in the edge region; A step of inserting the electrode assembly to which the current collector plate is joined into the receiving can such that the protruding rod penetrates the terminal hole and is exposed to the outside of the receiving can, thereby providing a welding recess defined by the chamfered surface and the inner surface of the terminal hole along the circumference of the terminal hole; and A step of welding the current collector plate and the terminal unit on the outside of the receiving can to form a welding bead that is integrally joined to the current collector plate and the terminal unit inside the welding recess. A method for manufacturing a secondary battery, comprising:

17. In claim 16, the step of forming the receiving can comprises: A step of forming a terminal insulator that is inserted into the through hole and provides an insulating hole having a size smaller than the through hole so as to cover the outer surface and inner surface of the base plate adjacent to the through hole; and A step of forming an electrode terminal, which includes an upper flange that covers an outer surface of the terminal insulator and is exposed to the outside, a lower flange that covers an inner surface of the terminal insulator and is located inside the receiving can, and a connecting cylinder that is connected to the upper flange and the lower flange and covers an inner surface of the insulating hole, wherein the terminal hole is provided in the central portion and has a smaller size than the insulating hole so as to surround the terminal insulator. A method for manufacturing a secondary battery, comprising:

18. In claim 17, A method for manufacturing a secondary battery, wherein the electrode assembly is inserted into the receiving can so as to have a gap with the inner surface of the connecting cylinder, the welding recess is formed to communicate with the gap, and the welding bead is formed to extend from the welding recess along the gap.

19. In claim 18, A method for manufacturing a secondary battery, wherein the welding bead is formed to be positioned lower than the outer surface of the upper flange exposed to the outside and to have a length in the range of 40% to 60% of the terminal thickness, which is the distance between the outer surface of the upper flange and the inner surface of the lower flange.

20. In claim 17, A method for manufacturing a secondary battery, wherein the electrode terminal is fixed to the terminal insulator by a rivet joint penetrating the insulating hole.

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