Secondary battery and method for manufacturing secondary battery

Abstract

Disclosed are a secondary battery and a method for manufacturing the same. A secondary battery includes an electrode assembly including a first electrode including a plurality of first substrate tabs extending in a first direction on one surface of the first electrode, a separator, and a second electrode including a plurality of second substrate tabs extending in a second direction on one surface of the first electrode, and the second electrode includes a plurality of second substrate tabs extending in the first direction on one surface of the second electrode; a case having one open surface and accommodating the electrode assembly; a cover covering the open surface of the case to seal the electrode assembly from the outside; a first bar terminal bonded to at least some of the plurality of first substrate tabs in a second direction perpendicular to the first direction; and a second bar terminal bonded to at least some of the plurality of second substrate tabs in the second direction.

Description

Technical Field

[0001] An aspect of the embodiments of this disclosure relates to a secondary battery and a method for manufacturing a secondary battery. Background Technology

[0002] Unlike primary batteries, which are not designed to be (re)charged, secondary (or rechargeable) batteries are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources to drive motors in hybrid and electric vehicles, as well as for storing electricity (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly containing positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] Typically, the electrode terminals of the electrode assembly are connected to the electrode terminals within the housing, and the electrode assembly is housed within the housing. This method allows for the manufacture of secondary batteries. For such secondary batteries, efforts can be made to efficiently utilize the space within the housing and to increase the energy density of the secondary battery.

[0004] The information disclosed in this background section is intended to enhance the understanding of the background art of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0005] To address the aforementioned technical problems, aspects of embodiments of this disclosure relate to a secondary battery and a method for manufacturing a secondary battery.

[0006] These and other aspects and features of this disclosure will be described in the following description of embodiments of this disclosure, or will become apparent from the following description of embodiments of this disclosure.

[0007] According to some embodiments of this disclosure, a secondary battery includes: an electrode assembly including a first electrode, a separator, and a second electrode, the first electrode including a plurality of first substrate tabs extending in a first direction on one surface of the first electrode, and the second electrode including a plurality of second substrate tabs extending in the first direction on one surface of the second electrode; a housing having an open surface and housing the electrode assembly; a cover covering the open surface of the housing to seal the electrode assembly from the outside; a first strip terminal engaged in at least some of the plurality of first substrate tabs in a second direction perpendicular to the first direction; and a second strip terminal engaged in at least some of the plurality of second substrate tabs in the second direction.

[0008] In some embodiments, the housing comprises stainless steel (SUS).

[0009] In some embodiments, the electrode assembly includes a first multi-terminal piece formed by welding at least some of the plurality of first substrate terminals and a second multi-terminal piece formed by welding at least some of the plurality of second substrate terminals.

[0010] In some embodiments, the first multi-connector includes a first connector soldering area, in which at least some of the plurality of first substrate connectors are soldered; the second multi-connector includes a second connector soldering area, in which at least some of the plurality of second substrate connectors are soldered; the first connector soldering area is located at the opposite end of the first multi-connector with respect to the second direction, and the second connector soldering area is located at the opposite end of the second multi-connector with respect to the second direction.

[0011] In some embodiments, the first multi-connector further includes a first terminal welding area welded to the first strip terminal, the second multi-connector further includes a second terminal welding area welded to the second strip terminal, and the first terminal welding area is located in the region of the first multi-connector outside the first terminal welding area, and the second terminal welding area is located in the region of the second multi-connector outside the second terminal welding area.

[0012] In some embodiments, the secondary battery further includes an insulating plate or insulating strip on a second surface opposite to the first surface of the first multi-terminal piece, wherein the first strip terminal is welded to the first surface.

[0013] In some embodiments, at least some of the plurality of first substrate terminals are joined by ultrasonic welding or laser welding to form the first multiple terminals, and at least some of the plurality of second substrate terminals are joined by ultrasonic welding or laser welding to form the second multiple terminals.

[0014] In some embodiments, the maximum thickness of the electrode assembly is less than 3 mm.

[0015] In some embodiments, the secondary battery further includes an insulating cap comprising two holes, the insulating cap being engaged to the electrode assembly by inserting each of the first multi-connector and the second multi-connector into the two holes.

[0016] In some embodiments, the first multi-connector includes a first bent portion, the first multi-connector being bent at the first bent portion, and the second multi-connector includes a second bent portion, the second multi-connector being bent at the second bent portion.

[0017] In some embodiments, the electrode assembly is inserted into the housing by bending the first bent portion and the second bent portion.

[0018] In some embodiments, the first strip terminal and the second strip terminal are welded to the inner surface of the housing.

[0019] In some embodiments, one end of the first strip terminal is engaged with at least some of the plurality of first substrate tabs, and one end of the second strip terminal is engaged with at least some of the plurality of second substrate tabs.

[0020] In some embodiments, the housing includes an electrolyte injection port on a surface perpendicular to the open surface.

[0021] In some embodiments, the first strip terminal is joined to at least some of the plurality of first substrate tabs by ultrasonic welding or laser welding, and the second strip terminal is joined to at least some of the plurality of second substrate tabs by ultrasonic welding or laser welding.

[0022] According to some embodiments of this disclosure, a method for manufacturing a secondary battery includes: forming an electrode assembly comprising a first electrode, a separator, and a second electrode, the first electrode comprising a plurality of first substrate tabs extending in a first direction on a surface of the first electrode, and the second electrode comprising a plurality of second substrate tabs extending in the first direction on a surface of the second electrode; joining at least some of the plurality of first substrate tabs by welding first strip terminals in a second direction perpendicular to the first direction; joining at least some of the plurality of second substrate tabs by welding second strip terminals in the second direction; joining the first strip terminals and the second strip terminals to an inner surface of a housing having an open surface by welding; inserting the electrode assembly into the housing by bending the plurality of first substrate tabs and the plurality of second substrate tabs; and covering the open surface of the housing with a cover to seal the electrode assembly from the outside.

[0023] In some embodiments, the method further includes: forming a first multi-terminal piece by welding at least some of the plurality of first substrate terminals; and forming a second multi-terminal piece by welding at least some of the plurality of second substrate terminals.

[0024] In some embodiments, the method further includes cutting at least a portion of one end of the first multi-connector or the second multi-connector.

[0025] In some embodiments, the method further includes: engaging the electrode assembly to the insulating cover by inserting each of the first multi-connector and the second multi-connector into two holes in the insulating cover.

[0026] In some embodiments, one end of the first strip terminal is engaged with at least some of the plurality of first substrate tabs, and one end of the second strip terminal is engaged with at least some of the plurality of second substrate tabs.

[0027] According to some embodiments of this disclosure, the strip terminal engages with the multi-connector while being positioned in the width direction of the electrode assembly, such that the strip terminal does not protrude upward from the multi-connector. Therefore, during the process of inserting the electrode assembly into the housing, no additional bending portion is required besides the first bending portion. Thus, after the electrode assembly is inserted into the housing, the space occupied by the multi-connector and the strip terminal in the longitudinal direction of the electrode assembly can be reduced (e.g., minimized). Therefore, the energy density of the secondary battery can be increased. Furthermore, the time and cost required for the bending process can be saved.

[0028] However, the aspects and features of this disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the detailed description described below. Attached Figure Description

[0029] The following accompanying drawings illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects and features of the present disclosure. Therefore, the present disclosure should not be construed as limited to the drawings.

[0030] Figure 1 An exploded perspective view of a secondary battery according to some embodiments of the present disclosure is shown.

[0031] Figure 2 A perspective view illustrating an electrode assembly according to some embodiments of the present disclosure.

[0032] Figures 3A to 3B Examples of some embodiments according to this disclosure are shown along Figure 2 A cross-sectional view taken from line A-A'.

[0033] Figure 4 An electrode assembly having a first contact welding area is illustrated in some embodiments of the present disclosure.

[0034] Figure 5 Examples of electrode assemblies coupled to strip terminals according to some embodiments of the present disclosure are shown.

[0035] Figure 6 An electrode assembly having a first terminal welding area is illustrated according to some embodiments of the present disclosure.

[0036] Figure 7 An electrode assembly having a second terminal welding area is illustrated according to some embodiments of the present disclosure.

[0037] Figure 8 Examples of welding strip terminals to a housing according to some embodiments of the present disclosure are shown.

[0038] Figure 9A An insulating board is illustrated according to some embodiments of the present disclosure.

[0039] Figure 9B Insulating tapes according to some embodiments of the present disclosure are illustrated.

[0040] Figures 10A to 10B Examples of inserting electrode assemblies into housings according to some embodiments of the present disclosure are shown.

[0041] Figure 11 An insulating cover is illustrated according to some embodiments of the present disclosure.

[0042] Figure 12 An electrode assembly coupled to an insulating cover is illustrated according to some embodiments of the present disclosure.

[0043] Figure 13 This is a flowchart illustrating a method for manufacturing a secondary battery according to some embodiments of the present disclosure.

[0044] Description of some figure labels

[0045] 10: Secondary batteries

[0046] 100: Electrode assembly

[0047] 110: First electrode

[0048] 112: First multi-connector

[0049] 114: First strip terminal

[0050] 116: First terminal

[0051] 120: Second electrode

[0052] 122: Second multi-connector

[0053] 124: Second strip terminal

[0054] 126: Second terminal

[0055] 130: Diaphragm

[0056] 140: Casing

[0057] 142: Electrolyte injection port

[0058] 150: Cover Detailed Implementation

[0059] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings, but should be interpreted in a manner consistent with the technical spirit of the present disclosure, based on the principle that the inventor is capable of interpreting his / her invention in the best way possible by appropriately defining the concepts of the terms as his / her own lexicographer.

[0060] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some of the embodiments of this disclosure and do not represent all the technical ideas, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications may exist that can replace or modify the embodiments described herein at the time of filing this application.

[0061] It will be understood that when a component or layer is referred to as being "on" another component or layer, "connected to," or "attached to" another component or layer, it can be directly on, connected to, or attached to the other component or layer, or one or more intermediate components or layers may be present. When a component or layer is referred to as being "directly" on another component or layer, "directly connected to," or "directly attached to" another component or layer, no intermediate components or layers are present. For example, when a first component is described as being "attached" or "connected" to a second component, the first component can be directly attached to or connected to the second component, or the first component can be indirectly attached to or connected to the second component via one or more intermediate components.

[0062] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity of illustration. The same reference numerals indicate the same elements. As used herein, the term “and / or” includes any and all combinations of one or more associated listed items. Furthermore, the use of “may” in describing embodiments of this disclosure refers to “one or more embodiments of this disclosure.” Expressions such as “at least one of…” and “any one of…” preceding / following the list of elements modify the entire list of elements, but not individual elements in the list. When phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one selected from the group of A, B, and C,” or “at least one selected from A, B, and C” are used to specify a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term “use” may be considered synonymous with the term “utilize.” As used herein, the terms “roughly,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to account for the inherent variations in measurements or calculations that would be apparent to a person skilled in the art.

[0063] It will be understood that while the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or segment from another element, component, region, layer, or segment. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment.

[0064] For ease of description, this document uses spatial relative terms such as “below,” “under,” “down,” “above,” and “above” to describe the relationship between one element or feature and another element or feature as shown in the figures. It should be understood that spatial relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features can be oriented as “above” or “above” other elements or features. Therefore, the term “below” can encompass both above and below orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0065] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to be limiting of this disclosure. As used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that, as used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0066] Furthermore, any numerical ranges disclosed and / or enumerated herein are intended to include all subranges with the same numerical precision contained within the enumerated ranges. For example, the range “1.0 to 10.0” is intended to include all subranges between the enumerated minimum value of 1.0 and the enumerated maximum value of 10.0 (and inclusive of both), i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit enumerated herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit enumerated in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify this specification, including the claims, to expressly enumerate any subranges contained within the scope expressly enumerated herein. All such ranges are intended to be inherently described in this specification such that modifications made to expressly enumerate any such subranges will be deemed appropriate.

[0067] Referring to two compared elements, features, etc., as “identical” may mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with deviations considered low in the art, such as less than 5%. Furthermore, when a parameter is said to be consistent in a given region, this may mean that it is consistent in terms of average value.

[0068] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0069] Placing any element "above (or below)" or "above (or below)" another element may mean that the arbitrary element can be configured to contact the upper (or lower) surface of the element, and other elements may be located between the element and any element positioned above (or below) the element.

[0070] Furthermore, it will be understood that when a component is referred to as “linked,” “connected,” or “attached” to another component, the components can be directly “linked,” “attached,” or “attached” to each other, or another component can be “between” the components.

[0071] Throughout this specification, unless otherwise stated, when “A and / or B” is used, it means A, B, or A and B. In other words, “and / or” includes any or all combinations of the listed items. Unless otherwise indicated, when “C to D” is used, it means C and below.

[0072] In this specification, unless the context explicitly specifies the singular form, the singular form as used herein also includes the plural form. Similarly, unless the context explicitly specifies the plural form, the plural form as used herein also includes the singular form. It will be understood that the terms "comprise / include" or "have" as used herein specify the presence of the stated element, but do not exclude the presence or addition of one or more other elements.

[0073] In this disclosure, for clarity of explanation, the dimensions and relative dimensions of layers and regions shown in the accompanying drawings may be enlarged. That is, the dimensions shown in the drawings are for ease of understanding only and are not limiting. Furthermore, throughout the specification, the same reference numerals denote the same elements.

[0074] Figure 1 An exploded perspective view of a secondary battery according to some embodiments of the present disclosure is shown. Figure 2 A perspective view illustrating an electrode assembly according to some embodiments of the present disclosure.

[0075] refer to Figure 1 and Figure 2 The secondary battery 10 according to this disclosure may include an electrode assembly 100, a housing 140 having an open surface and housing the electrode assembly 100, and a cover 150 covering the open surface of the housing 140 to seal the electrode assembly 100 from the outside. The electrode assembly 100 may include a first electrode 110, a second electrode 120, and a separator 130 disposed between the first electrode 110 and the second electrode 120.

[0076] In some embodiments, the electrode assembly 100 can be formed by winding or stacking a first electrode 110, a diaphragm 130, and a second electrode 120, which are formed into a sheet or film shape. In an example where the electrode assembly 100 is wound, the winding axis can be parallel to the vertical axis of the housing 140. The direction parallel to the vertical axis of the housing 140 can be... Figure 1The first direction is Y. Furthermore, the electrode assembly 100 can be stacked rather than wound. In an example where the electrode assembly 100 is formed as a stack, the first electrode 110 and the second electrode 120 can be stacked sequentially, and the diaphragm 130 can be disposed between the first electrode 110 and the second electrode 120. In this disclosure, the shape of the electrode assembly 100 is not particularly limited. Furthermore, the electrode assembly 100 can be a Z-stacked electrode assembly 100 in which the first electrode 110 and the second electrode 120 are inserted on opposite sides of the diaphragm 130, which is bent into a Z-stack. The electrode assembly 100 can be housed within the housing 140 by stacking one or more electrode assemblies 100 such that their long sides are adjacent to each other. In this disclosure, the number of electrode assemblies 100 is not particularly limited. In the electrode assembly 100, the first electrode 110 can be used as a positive electrode, and the second electrode 120 can be used as a negative electrode. Of course, the reverse is also possible.

[0077] The first electrode 110 can be formed by coating an active material, such as a transition metal oxide, onto a current collector plate formed of a metal foil such as aluminum or an aluminum alloy. The first electrode 110 may include a first uncoated portion as a region where no active material is coated. The first uncoated portion may be connected to a separately formed first substrate tab, or a portion of the first uncoated portion may be stamped to form the first substrate tab.

[0078] The second electrode 120 can be formed by coating an active material such as graphite or carbon onto a current collector plate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The second electrode 120 may include a second uncoated portion as a region where no active material is coated. The second uncoated portion may be connected to a separately formed second substrate tab, or a portion of the second uncoated portion may be stamped to form a second substrate tab.

[0079] A diaphragm 130 may be disposed between the first electrode 110 and the second electrode 120 to prevent electrical short circuits. For example, the diaphragm 130 may be formed of polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer thereof consisting of two or more layers. However, the composition of the diaphragm 130 according to this disclosure is not limited thereto.

[0080] The structure of the electrode assembly 100 described above is merely an example, and this disclosure is not limited thereto.

[0081] refer to Figure 2The first electrode 110 may include a plurality of first substrate tabs 111 extending in a first direction Y on one surface of the first electrode 110. The first substrate tabs 111 can serve as current flow paths between the first electrode 110 and the first terminal 116. Similarly, the second electrode 120 may include a plurality of second substrate tabs 121 extending in a first direction Y on one surface of the second electrode 120. The second substrate tabs 121 can serve as current flow paths between the second electrode 120 and the second terminal 126. For example, the first terminal 116 may be in the form of a lead made of aluminum (Al), and the second terminal 126 may be in the form of a plate made of nickel (Ni). However, the materials and shapes of the first terminal 116 and the second terminal 126 are not limited thereto.

[0082] In some embodiments, the housing 140 may include a sealed electrolyte inlet 142, which serves as a channel for injecting electrolyte after accommodating the electrode assembly 100. The electrolyte inlet 142 may be disposed on a surface perpendicular to the open surface of the housing 140.

[0083] The housing 140 may comprise a conductive metal such as aluminum, aluminum alloy, stainless steel (SUS), or nickel-plated steel. In some embodiments, the housing 140 may comprise stainless steel (SUS). Because the housing 140 comprises stainless steel (SUS), the mechanical strength of the secondary battery 10 may be increased (e.g., enhanced).

[0084] In some embodiments, the electrode assembly 100 may include a first multi-connection tab 112 formed by welding at least some of the first substrate tabs 111 and a second multi-connection tab 122 formed by welding at least some of the second substrate tabs 121.

[0085] In some embodiments, the secondary battery 10 according to the present disclosure may include at least some first strip terminals 114 that are coupled to at least some of the first substrate terminals 111 in the second direction X, and at least some second strip terminals 124 that are coupled to at least some of the second substrate terminals 121 in the second direction X.

[0086] The first electrode 110 and the second electrode 120 may have a symmetrical structure. In the following description, the focus is on the first electrode 110, omitting details of the specific configuration of the second electrode 120, and primarily describing its differences from the first electrode 110. Therefore, any parts of the second electrode 120 not described may be the same as or similar to the description of the first electrode 110.

[0087] Figures 3A to 3B Examples of some embodiments according to this disclosure are shown along Figure 2 A cross-sectional view taken from line A-A'. Figures 3A to 3BThe electrode assembly 300 illustrated in the example can correspond to Figure 1 and Figure 2 Electrode assembly 100. In this disclosure, electrode assembly 300 may include a plurality of first electrodes 310, a plurality of second electrodes 320, and a diaphragm 330 disposed between adjacent first electrodes 310 and second electrodes 320.

[0088] refer to Figure 3A In some embodiments, the first electrode 310 may include a plurality of first substrate tabs 312 disposed on one surface of the first electrode 310 extending in a first direction Y. The first substrate tabs 312 may be formed to protrude upward from the electrode assembly 300.

[0089] refer to Figure 3B In some embodiments, at least some of the first substrate terminals 312 can be combined to form a first multiple terminal block 314. In these examples, at least some of the first substrate terminals 312 can be soldered to form the first multiple terminal block 314. When forming the first multiple terminal block 314, at least some of the first substrate terminals 312 can be joined by ultrasonic welding, laser welding, or the like. The first multiple terminal block 314 can refer to a plurality of first substrate terminals 312 soldered together to form an electrode terminal block. By soldering the first substrate terminals 312 to form the first multiple terminal block 314, the adhesion between the first substrate terminals 312 can be improved (e.g., increased).

[0090] refer to Figure 3B The first substrate tabs 312 can be overlapped in a third direction Z to form a first multiple tab 314. The first multiple tab 314 can refer to a plurality of first substrate tabs 312 welded together to form an electrode tab. The third direction Z can be the thickness direction of the electrode assembly 300. The third direction Z can be perpendicular to the first direction Y and the second direction X.

[0091] A process of cutting the first multi-connection tab 314 may be required to insert the electrode assembly 300 into the housing. Because the first multi-connection tab 314 is formed by pre-soldering the first substrate tab 312, the first substrate tab 312 can be effectively fixed, and the uniformity of the cut surface can be improved (e.g., increased).

[0092] In some embodiments, the maximum thickness of the electrode assembly 300 may be less than 3 mm.

[0093] Since the first multi-connection tab 314 is formed by pre-soldering the first substrate tab 312, the first substrate tab 312 can be cut without using a separate guide to gather and fix the first substrate tab 312 to one side. Therefore, compared to cutting the first multi-connection tab 314 using a separate guide, the length of the first multi-connection tab 314 (e.g., the length of the first multi-connection tab 314 in the first direction Y) can be cut shorter. By cutting the length of the first multi-connection tab 314 shorter, the number of times the first multi-connection tab 314 is bent when the electrode assembly 300 is inserted into the housing can be reduced. Therefore, the height after bending the first multi-connection tab 314 can be effectively reduced, and thus, the maximum thickness T of the electrode assembly 300 can also be reduced.

[0094] Figure 4 An electrode assembly having a first contact welding area is illustrated in some embodiments of the present disclosure. Figure 4 The electrode assembly 400 shown can correspond to Figure 1 and Figure 2 Electrode assembly 100.

[0095] refer to Figure 4 The electrode assembly 400 according to this disclosure may include a first multi-connection tab 412 extending in a first direction Y on one surface of the first electrode 410.

[0096] In some embodiments, the first multi-connector 412 may include first connector soldering areas 414 therein where at least some of the first substrate connectors are soldered. The first connector soldering areas 414 may be located at opposite ends of the first multi-connector 412 with respect to a second direction X. For example, the first connector soldering areas 414 may be located at opposite ends of the first multi-connector 412 with respect to the second direction X, excluding the central portion. Alternatively or additionally, the first connector soldering areas 414 may be located at the ends of the first multi-connector 412, including the central portion of the first multi-connector 412. As used herein, the phrase "with respect to a direction" may be interchanged with "along a direction".

[0097] Figure 5 Examples of electrode assemblies coupled to strip terminals according to some embodiments of the present disclosure are shown. Figure 5 The electrode assembly 500 shown can correspond to the electrode assembly 300 in FIG3.

[0098] refer to Figure 5The electrode assembly 500 may include a first electrode 510, a second electrode 520, and a diaphragm 530 disposed between the first electrode 510 and the second electrode 520. The first electrode 510 may include a plurality of first substrate tabs extending in a first direction Y on one surface of the first electrode 510. Furthermore, at least some of the first substrate tabs may be soldered to form a first multi-tab 512. The first multi-tab 512 may refer to a plurality of first substrate tabs soldered together to form an electrode tab.

[0099] In some embodiments, the first strip terminal 540 may be engaged to one side of the first multi-connector 512. The surface of the first multi-connector 512 that engages the first strip terminal 540 may be the outer surface of the electrode assembly 500 about a third direction Z.

[0100] In some embodiments, the first strip terminal 540 may be soldered to the first multi-connector patch 512. The first strip terminal 540 may be joined by ultrasonic welding, laser welding, or the like. Therefore, the first multi-connector patch 512 may include a first terminal soldering area soldered to the first strip terminal 540. The first terminal soldering area may not overlap with the first patch soldering area.

[0101] Figure 6 An electrode assembly having a first terminal welding area is illustrated according to some embodiments of the present disclosure. Figure 6 The electrode assembly 600 shown can correspond to Figure 2 Electrode assembly 100.

[0102] refer to Figure 6 The electrode assembly 600 may include a first electrode 610, a diaphragm, and a second electrode 620. The first electrode 610 may include a plurality of first substrate tabs disposed on one surface of the first electrode 610 extending in a first direction Y. At least some of the first substrate tabs may be soldered to form a first multi-tab 612. The first multi-tab 612 may refer to a plurality of first substrate tabs soldered together to form an electrode tab. A first tab soldering region 614 may be formed in the first multi-tab 612 in which at least some of the first substrate tabs are soldered. The first tab soldering region 614 may be located at the opposite end of the first multi-tab 612 with respect to the second direction X. For example, the first tab soldering region 614 may be located at the opposite end of the first multi-tab 612 with respect to the second direction X, excluding the central portion. Additionally or optionally, in Figure 6 In the process, the first connector welding area 614 may be located at the end of the first multi-connector 612, including the central part of the first multi-connector 612.

[0103] In some embodiments, a first strip terminal 640 disposed in the second direction X can engage at least a portion of the first multi-connector 612. That is, the first strip terminal 640 can engage with the first multi-connector 612 while its long side is disposed parallel to the second direction X. Because the first strip terminal 640 engages with the first multi-connector 612 while disposed parallel to the second direction X, the first strip terminal 640 does not need to protrude upward from the first multi-connector 612. Therefore, the portion protruding upward from the stack in which the first electrode 610, the second electrode 620, and the diaphragm are stacked about the first direction Y can be reduced (e.g., minimized).

[0104] In some embodiments, one end of the first strip terminal 640 may be engaged with at least a portion of the first multi-connector tab 612. (See reference...) Figure 6 It can be observed that the left end of the first strip terminal 640 engages with the first multi-connector 612. Therefore, the right end of the first strip terminal 640 can be configured to protrude to the right side of the first multi-connector 612 without engaging with it. Here, the terms "left" and "right" are defined relative to the second direction X. In some examples, in Figure 6 In this configuration, the left end of the first strip terminal 640 can be configured to protrude to the left side of the first multi-connector 612, and the right end of the first strip terminal 640 can be configured to protrude to the right side of the first multi-connector 612. The central portion of the first strip terminal 640, excluding the left and right ends, can be engaged with the first multi-connector 612.

[0105] In some embodiments, the first strip terminal 640 may be soldered to at least a portion of the first multi-connector 612. The first strip terminal 640 may be joined to at least a portion of the first multi-connector 612 by ultrasonic welding, laser welding, or the like.

[0106] In some embodiments, the first multi-connector 612 may include a first terminal soldering area 642 soldered to the first strip terminal 640. The first terminal soldering area 642 may be located in an area of ​​the first multi-connector 612 other than the first connector soldering area 614 (e.g., outside the first connector soldering area 614). Reference Figure 6It can be observed that the first connector welding area 614 is provided at each end of the first multi-connector 612 in the second direction X, except for the central portion, and the first terminal welding area 642 is provided at the central portion of the first multi-connector 612 where the first connector welding area 614 is not provided. Because the first connector welding area 614 and the first terminal welding area 642 are configured not to overlap with each other, damage caused by repeated welding processes will not accumulate, thereby preventing or significantly reducing the incidence of cracks. Furthermore, because the area of ​​the first multi-connector 612 where the first connector welding area 614 is not provided can form a uniform surface, the welding quality can be improved in the example of welding the first strip terminal 640.

[0107] In some embodiments, a first coating 630 may be formed in the portion of the first multi-connector 612 that protrudes from the first electrode 610. The first coating 630 may comprise at least one of polyimide and ceramic. For example, the second electrode 620 may be manufactured to be larger than the first electrode 610. The first coating 630 may be used to insulate between the first multi-connector 612 and the second electrode 620. Therefore, short circuits may be prevented between the first electrode 610 and the second electrode 620, or between the first multi-connector 612 and the second electrode 620.

[0108] Figure 7 An electrode assembly having a second terminal welding area is illustrated according to some embodiments of the present disclosure. Figure 7 The electrode assembly 700 shown can correspond to Figure 2 Electrode assembly 100.

[0109] refer to Figure 7 The electrode assembly 700 may include a first electrode 710, a diaphragm, and a second electrode 720. The second electrode 720 may include a plurality of second substrate tabs disposed on one surface of the second electrode 720 extending in a first direction Y. At least some of the second substrate tabs may be soldered to form a second multi-tab 712. The second multi-tab 712 may refer to a plurality of second substrate tabs soldered together to form an electrode tab. A second tab soldering region 714 may be formed in at least some of the second substrate tabs in the second multi-tab 712 in which they are soldered. The second tab soldering region 714 may be disposed at opposite ends of the second multi-tab 712 with respect to the second direction X. For example, the second tab soldering region 714 may be disposed at opposite ends of the second multi-tab 712 with respect to the second direction X, excluding the central portion. Additionally or optionally, in Figure 7 In the process, the second connector welding area 714 may be located at the end of the second multi-connector 712, including the central portion of the second multi-connector 712.

[0110] In some embodiments, a second strip terminal 740 disposed in the second direction X can engage at least a portion of the second multi-connector 712. That is, the second strip terminal 740 can engage with the second multi-connector 712 while its long side is disposed parallel to the second direction X. Because the second strip terminal 740 engages with the second multi-connector 712 while disposed parallel to the second direction X, the second strip terminal 740 does not need to protrude upward from the second multi-connector 712. Therefore, the portion protruding upward from the stack in which the first electrode 710, the second electrode 720, and the diaphragm are stacked about the first direction Y can be reduced (e.g., minimized).

[0111] In some embodiments, one end of the second strip terminal 740 may be engaged with at least a portion of the second multi-connector 712. (See reference...) Figure 7 It can be observed that the right end of the second strip terminal 740 engages with the second multi-connector 712. Therefore, the left end of the second strip terminal 740 can be configured to protrude to the left side of the second multi-connector 712 without engaging with it. In some examples, in Figure 7 In this configuration, the left end of the second strip terminal 740 can be configured to protrude to the left side of the second multi-connector 712, and the right end of the second strip terminal 740 can be configured to protrude to the right side of the second multi-connector 712. The central portion of the second strip terminal 740, excluding the left and right ends, can be engaged with the second multi-connector 712.

[0112] In some embodiments, the second strip terminal 740 may be soldered to at least a portion of the second multi-connector 712. The second strip terminal 740 may be joined to at least a portion of the second multi-connector 712 by ultrasonic welding, laser welding, or the like.

[0113] In some embodiments, the second multi-connector 712 may include a second terminal soldering area 742 soldered to the second strip terminal 740. The second terminal soldering area 742 may be located in a region of the second multi-connector 712 other than the second connector soldering area 714 (e.g., outside the second connector soldering area 714). Reference Figure 7It can be observed that the second connector welding area 714 is provided at each end of the second multi-connector 712 in the second direction X, except for the central portion, and the second terminal welding area 742 is provided at the central portion of the second multi-connector 712 where the second connector welding area 714 is not provided. Because the second connector welding area 714 and the second terminal welding area 742 are configured not to overlap with each other, damage caused by repeated welding processes will not accumulate, thereby preventing or significantly reducing the incidence of cracks. Furthermore, because the area of ​​the second multi-connector 712 where the second connector welding area 714 is not provided can form a uniform surface, the welding quality can be improved in the example of welding the second strip terminal 740.

[0114] Figure 8 Examples of welding strip terminals to a housing according to some embodiments of the present disclosure are shown.

[0115] In some embodiments, the electrode assembly 800 may include a first electrode, a diaphragm, and a second electrode. The first electrode may include a plurality of first substrate tabs disposed on one surface of the first electrode extending in a first direction Y. At least some of the first substrate tabs may be soldered to form a first multi-tab 812. The first multi-tab 812 may refer to a plurality of first substrate tabs soldered together to form an electrode tab. Similarly, the second electrode may include a plurality of second substrate tabs disposed on one surface of the second electrode extending in a first direction Y. At least some of the second substrate tabs may be soldered to form a second multi-tab 822. The second multi-tab 822 may refer to a plurality of second substrate tabs soldered together to form an electrode tab.

[0116] In some embodiments, a first strip terminal 814 disposed in the second direction X can be engaged with at least a portion of a first multi-connector 812. That is, the first strip terminal 814 can be engaged with the first multi-connector 812 while its long side is parallel to the second direction X. Because the first strip terminal 814 is engaged with the first multi-connector 812 while being parallel to the second direction X, the first strip terminal 814 does not need to protrude upward from the first multi-connector 812. Similarly, a second strip terminal 824 disposed in the second direction X can be engaged with at least a portion of a second multi-connector 822. That is, the second strip terminal 824 can be engaged with the second multi-connector 822 while its long side is parallel to the second direction X. Because the second strip terminal 824 is engaged with the second multi-connector 822 while being parallel to the second direction X, the second strip terminal 824 does not need to protrude upward from the second multi-connector 822. Therefore, the portion protruding upward from the stack in which the first electrode, the second electrode, and the diaphragm are stacked about the first direction Y can be reduced (e.g., minimized).

[0117] In some embodiments, the first strip terminal 814 and the second strip terminal 824 can be soldered to the inner surface 842 of the housing 840. For example... Figure 8 As shown, the surface of the first strip terminal 814 opposite to the surface that contacts the first multi-connector 812 can contact the housing 840. Similarly, the surface of the second strip terminal 824 opposite to the surface that contacts the second multi-connector 822 can contact the housing 840. With this configuration, the flat surfaces of the strip terminals 814 and 824 can contact the housing 840, and in examples where the housing 840 and the strip terminals 814 and 824 are welded together, the weld quality can be improved.

[0118] Figure 9A An insulating board is illustrated according to some embodiments of the present disclosure.

[0119] In some embodiments, an insulating plate 950 may be disposed on the first multi-connector tab 912 and the second multi-connector tab 922. The insulating plate 950 may be plate-shaped. The insulating plate 950 may be formed of an insulating material including polyimide, polypropylene, etc. The insulating plate 950 may be disposed on a second surface of the first multi-connector tab 912 opposite to the first surface soldered to the first strip terminal. Figure 9A As shown, the first surface can be the lower surface of the first multi-connector 912 about a third direction Z, and the second surface can be the upper surface of the first multi-connector 912 about a third direction Z. Therefore, the first strip terminal can be disposed on the lower surface of the first multi-connector 912, and the insulating plate 950 can be disposed on the upper surface of the first multi-connector 912. See below for reference. Figures 10A to 10B The insulating plate 950 can be used to partially insulate the contact area between the first multi-connector 912 and the second multi-connector 922 when they are bent.

[0120] Figure 9B Insulating tapes according to some embodiments of the present disclosure are illustrated.

[0121] In some embodiments, an insulating tape 960 may be disposed on the first multi-connector 912 and the second multi-connector 922. The insulating tape 960 may be in the form of a film. The insulating tape 960 may be formed of an insulating material including polyimide, polypropylene, etc. The insulating tape 960 may be disposed on a second surface of the first multi-connector 912 opposite to the first surface soldered to the first strip terminal. Figure 9BAs shown, the first surface can be the lower surface of the first multi-connector 912 about a third direction Z, and the second surface can be the upper surface of the first multi-connector 912 about a third direction Z. Therefore, the first strip terminal can be disposed on the lower surface of the first multi-connector 912, and the insulating tape 960 can be disposed on the upper surface of the first multi-connector 912. The insulating tape 960 can be used to partially insulate the contact area between the first multi-connector 912 and the second multi-connector 922 when bent.

[0122] Furthermore, a hole 962 may be formed in the central portion of the insulating strip 960. The hole 962 may be formed about a third direction (Z) relative to an electrolyte injection port located on one surface of the housing 940 (e.g., corresponding to...). Figure 1 The electrolyte injection port 142 is located at the corresponding position. Therefore, even in the example where the insulating tape 960 is attached to a surface of the housing 940, the electrolyte injection port may not be sealed, and the electrolyte can be injected through the hole 962.

[0123] Figures 10A to 10B Examples of inserting electrode assemblies into housings according to some embodiments of the present disclosure are shown.

[0124] refer to Figures 10A to 10B As can be observed, the electrode assembly 1000 includes a first electrode 1010, a second electrode 1020, and a diaphragm 1030; a plurality of first substrate tabs extending in a first direction Y on one surface of the first electrode 1010; a first multi-tab 1012 formed by welding at least some of the first substrate tabs; a first strip terminal 1014 disposed on one surface of the first multi-tab 1012; and an insulating plate 1050 disposed on another surface of the first multi-tab 1012 opposite to the first surface. Furthermore, the surface of the first strip terminal 1014 opposite to the surface contacting the first multi-tab 1012 can contact the inner surface 1042 of the housing 1040.

[0125] In some embodiments, the first multi-connector 1012 may include a first bent portion 1016, which is the portion in which the first multi-connector 1012 is bent. The first bent portion 1016 may be disposed between the portion of the first multi-connector 1012 that contacts the first strip terminal 1014 and the portion of the first substrate connector that begins to protrude from the first electrode 1010. Because the first bent portion 1016 is bent, the electrode assembly 1000 can be inserted into the housing 1040.

[0126] In some embodiments, the first strip terminal 1014 can be engaged with at least a portion of the first multi-connector 1012 while being disposed in the second direction X. That is, the first strip terminal 1014 can be engaged with the first multi-connector 1012 while its long side is parallel to the second direction X. Because the first strip terminal 1014 is engaged with the first multi-connector 1012 while being disposed in the second direction X, the first strip terminal 1014 does not need to protrude upward from the first multi-connector 1012. That is, even in the example where the first strip terminal 1014 is engaged with the first multi-connector 1012, the first strip terminal 1014 does not need to protrude in the first direction Y. Therefore, during the process of inserting the electrode assembly 1000 into the housing 1040, no additional bending section is required besides the first bending portion 1016, such as... Figure 10B As shown in the diagram. Therefore, after inserting the electrode assembly 1000 into the housing 1040, the space occupied by the first multi-connector 1012 and the first strip terminal 1014 in the third direction (Z, e.g., the longitudinal direction of the electrode assembly 1000) can be reduced (e.g., minimized). This allows for an increase (e.g., an improvement) in the energy density of the secondary battery. Furthermore, since the electrode assembly 1000 can be inserted into the housing 1040 without an additional bending process other than bending the first bent portion 1016, the time and cost required for the bending process can be saved.

[0127] Figure 11 An insulating cover is illustrated according to some embodiments of the present disclosure. Figure 12 An electrode assembly coupled to an insulating cover is illustrated according to some embodiments of the present disclosure.

[0128] As illustrated, the insulating cover 1100 may have a rectangular shape including two holes 1110. However, the shape of the insulating cover 1100 is not limited to this.

[0129] In some embodiments, the insulating cover 1100 may be formed of an insulating material including polyimide, polypropylene, etc. The insulating cover 1100 can be coupled to the electrode assembly 1200 by inserting the first multi-connector 1210 and the second multi-connector 1220 through or into the two holes 1110 included in the insulating cover 1100. Therefore, the two holes 1110 may be larger than the first multi-connector 1210 and the second multi-connector 1220. However, the dimensional difference may be small for the insulating cover 1100 to perform insulation. The insulating cover 1100 can be used for insulation between the first multi-connector 1210 and the second multi-connector 1220, between the first multi-connector 1210 and the second multi-connector 1220 and the first electrode, or between the first multi-connector 1210 and the second multi-connector 1220 and the second electrode. Furthermore, the insulating cover 1100 can be used to replace... Figures 10A to 10BThe insulating plate 1050 shown is shown.

[0130] Figure 13 This is a flowchart illustrating a method for manufacturing a secondary battery 10 according to some embodiments of the present disclosure.

[0131] refer to Figure 13 According to some embodiments of the present disclosure, a method S1300 for manufacturing a secondary battery 10 may begin by forming an electrode assembly 100 including a first electrode 110, a separator 130, and a second electrode 120 (S1310). The first electrode 110 may include a plurality of first substrate tabs 111 disposed on one surface of the first electrode 110 extending in a first direction, and the second electrode 120 may include a plurality of second substrate tabs 121 disposed on one surface of the second electrode 200 extending in a first direction.

[0132] In some embodiments, the method S1300 for manufacturing a secondary battery 10 may include forming a first multi-connection piece 112 by welding at least some of a plurality of first substrate terminals 111 and forming a second multi-connection piece 122 by welding at least some of a plurality of second substrate terminals 121. The first multi-connection piece 112 may refer to a plurality of first substrate terminals 111 welded together to form an electrode terminal, and the second multi-connection piece 122 may refer to a plurality of second substrate terminals 121 welded together to form an electrode terminal. At least some of the first substrate terminals 111 may be joined by ultrasonic welding, laser welding, or the like to form the first multi-connection piece 112, and at least some of the second substrate terminals 121 may be joined by ultrasonic welding, laser welding, or the like to form the second multi-connection piece 122. Because both the first substrate terminals 111 and the second substrate terminals 121 are welded together to form an electrode terminal, the uniformity of the cut surfaces on which the first multi-connection piece 112 or the second multi-connection piece 122 is cut can be improved (e.g., increased). This can improve the performance or durability of the first multi-connector 112 or the second multi-connector 122, thereby also improving the performance or durability of the secondary battery 10.

[0133] In some embodiments, the method S1300 for manufacturing a secondary battery 10 may include cutting at least a portion of one end of a first multi-connector 112 or a second multi-connector 122.

[0134] In some embodiments, the method S1300 for manufacturing a secondary battery 10 may include engaging the electrode assembly 100 and the insulating cover by inserting a first multi-connector 112 and a second multi-connector 122 into two holes included in the insulating cover, respectively.

[0135] Next, the first strip terminal 114 can be soldered and joined to at least some of the first substrate terminals 111 in a second direction perpendicular to the first direction (S1320), and the second strip terminal 124 can be soldered and joined to at least some of the second substrate terminals 121 in the second direction (S1330). One end of the first strip terminal 114 can be joined to at least some of the first substrate terminals 111, and one end of the second strip terminal 124 can be joined to at least some of the second substrate terminals 121. The first strip terminal 114 and the second strip terminal 124 can be joined by ultrasonic welding, laser welding, or the like.

[0136] Next, the first strip terminal 114 and the second strip terminal 124 can be soldered and joined to the inner surface of the housing having an open surface (S1340). In some examples, the surface of the first strip terminal 114 opposite to the surface that contacts the first multi-connector 112 can contact the housing. Similarly, the surface of the second strip terminal 124 opposite to the surface that contacts the second multi-connector 122 can contact the housing.

[0137] Next, the electrode assembly 100 can be inserted into the housing by bending the first substrate connector 111 and the second substrate connector 121 (S1350). In some examples, the first substrate connector 111 may include a first bent portion to be bent. The first bent portion may be disposed between the portion of the first substrate connector 111 that contacts the first strip terminal 114 and the portion of the first substrate connector 111 that begins to protrude from the first electrode 110. By bending the first bent portion, the electrode assembly 100 can be inserted into the housing. Similarly, the second substrate connector 121 may include a second bent portion to be bent. The second bent portion may be disposed between the portion of the second substrate connector 121 that contacts the second strip terminal 124 and the portion of the second substrate connector 121 that begins to protrude from the second electrode 120. By bending the second bent portion, the electrode assembly 100 can be inserted into the housing.

[0138] Next, the open surface of the housing is covered with a cover to seal the electrode assembly 100 from the outside (S1360).

[0139] Figure 13 The flowcharts shown and the above description are merely examples and may be implemented differently in some embodiments. For example, one or more steps may be omitted, the order of the steps may be changed, one or more steps may be performed while overlapping each other, or one or more steps may be repeated multiple times.

[0140] Preferred embodiments of this disclosure have been disclosed for illustrative purposes, and those skilled in the art will understand that various modifications, alterations, and additions are possible within the spirit and scope of this disclosure, and such modifications, alterations, and additions should be considered to fall within the scope of the claims.

[0141] Those skilled in the art will understand that various substitutions, modifications, and changes can be made without departing from the technical spirit of this disclosure. Therefore, this disclosure is not limited to the above embodiments and drawings.

[0142] While this disclosure has been described above with reference to some embodiments thereof, it is not limited thereto. Various appropriate modifications and variations can be made to it by those skilled in the art within the spirit and scope of the disclosure as defined by the claims and their equivalents.

Claims

1. A secondary battery comprising: an electrode assembly including a first electrode, a separator, and a second electrode, the first electrode including a plurality of first substrate tabs extending in a first direction on one surface of the first electrode, and the second electrode including a plurality of second substrate tabs extending in the first direction on one surface of the second electrode; a case having one open surface and accommodating the electrode assembly; a cover covering the open surface of the case to seal the electrode assembly from the outside; a first strip terminal joined to at least some of the plurality of first substrate tabs in a second direction perpendicular to the first direction; and a second strip terminal joined to at least some of the plurality of second substrate tabs in the second direction. 2.The secondary battery of claim 1, wherein the case comprises stainless steel. 3.The secondary battery of claim 1, wherein the electrode assembly includes a first multiple tab formed by welding the at least some of the plurality of first substrate tabs, and a second multiple tab formed by welding the at least some of the plurality of second substrate tabs. 4.The secondary battery of claim 3, wherein the first multiple tab includes a first tab welding area in which the at least some of the plurality of first substrate tabs are welded, wherein the second multiple tab includes a second tab welding area in which the at least some of the plurality of second substrate tabs are welded, wherein the first tab welding area is at opposite ends of the first multiple tab with respect to the second direction, and wherein the second tab welding area is at opposite ends of the second multiple tab with respect to the second direction. 5.The secondary battery of claim 4, wherein the first multiple tab further includes a first terminal welding area welded to the first strip terminal, wherein the second multiple tab further includes a second terminal welding area welded to the second strip terminal, and wherein the first terminal welding area is in a region of the first multiple tab outside of the first tab welding area, and the second terminal welding area is in a region of the second multiple tab outside of the second tab welding area. 6.The secondary battery of claim 5, further comprising an insulating plate or an insulating tape on a second surface of the first multiple tab opposite a first surface of the first multiple tab to which the first strip terminal is welded. 7.The secondary battery of claim 3, wherein the at least some of the plurality of first substrate tabs are joined by ultrasonic welding or laser welding to form the first multiple tab, and wherein the at least some of the plurality of second substrate tabs are joined by ultrasonic welding or laser welding to form the second multiple tab. 8.The secondary battery of claim 3, wherein a maximum thickness of the electrode assembly is 3 mm or less. ​ 9.The secondary battery of claim 3, further comprising an insulating cover including two holes, wherein the insulating cover is coupled to the electrode assembly by inserting each of the first and second multi-tabs into the two holes. 10.The secondary battery of claim 3, wherein the first multi-tab includes a first bending portion at which the first multi-tab is bent, and wherein the second multi-tab includes a second bending portion at which the second multi-tab is bent. 11.The secondary battery of claim 10, wherein the electrode assembly is inserted into the case by bending the first and second bending portions. 12.The secondary battery of claim 1, wherein the first and second strip terminals are welded to an inner surface of the case. 13.The secondary battery of claim 1, wherein one end of the first strip terminal is coupled to the at least some of the first plurality of substrate tabs, and wherein one end of the second strip terminal is coupled to the at least some of the second plurality of substrate tabs. 14.The secondary battery of claim 1, wherein the case includes an electrolyte injection port on a surface perpendicular to the open surface. 15.The secondary battery of claim 1, wherein the first strip terminal is coupled to the at least some of the first plurality of substrate tabs by ultrasonic welding or laser welding, and wherein the second strip terminal is coupled to the at least some of the second plurality of substrate tabs by ultrasonic welding or laser welding. 16.A method for manufacturing a secondary battery, the method comprising: forming an electrode assembly including a first electrode, a separator, and a second electrode, the first electrode including a first plurality of substrate tabs extending in a first direction on one surface of the first electrode, and the second electrode including a second plurality of substrate tabs extending in the first direction on one surface of the second electrode; coupling a first strip terminal to at least some of the first plurality of substrate tabs in a second direction perpendicular to the first direction by welding; coupling a second strip terminal to at least some of the second plurality of substrate tabs in the second direction by welding; coupling the first and second strip terminals to an inner surface of a case having one open surface by welding; inserting the electrode assembly into the case by bending the first and second plurality of substrate tabs; and covering the open surface of the case with a cover to seal the electrode assembly from the outside. 17.The method of claim 16, further comprising: forming a first multi-tab by welding the at least some of the first plurality of substrate tabs; and forming a second multi-tab by welding the at least some of the second plurality of substrate tabs. ​ 18. The method of claim 17, further comprising: cutting at least a portion of one end of the first or second multiplicity of tabs.

19. The method of claim 17, further comprising: joining the electrode assembly to an insulating cover by inserting each of the first and second multiplicity of tabs into two holes of the insulating cover.

20. The method of claim 16, wherein one end of the first strip terminal is joined to the at least some of the first plurality of substrate tabs, and one end of the second strip terminal is joined to the at least some of the second plurality of substrate tabs.

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