Secondary battery

Abstract

An embodiment of the present invention relates to a secondary battery, the secondary battery comprising: a plurality of electrode assemblies, each comprising a plurality of first electrode plates, a plurality of second electrode plates, and a plurality of separators between respective first and second electrode plates; a case for accommodating the electrode assemblies; a plurality of first current collector plates electrically connected to the first electrode plates; and a plurality of second current collector plates electrically connected to the second electrode plates; and cap assembly comprising first and second terminals electrically connected to the respective first and second current collector plates, and a cap plate that couples to the case. According to an embodiment of the present invention, by having a plurality of electrode assemblies and current collector plates electrically connected thereto, weldability of the electrode assemblies can be improved. Accordingly, a secondary battery of high capacity and high density can be provided.

Description

secondary batteries

[0001] An embodiment of the present invention relates to a secondary battery capable of implementing high capacity and high density.

[0002] Secondary batteries are categorized into square, cylindrical, and pouch types based on their case shape. In the case of square secondary batteries, a cap assembly is attached to one or both ends of a rectangular parallelepiped case, and a coiled or stacked electrode assembly is housed inside. For secondary batteries installed in electric vehicles, high capacity is essential for long-distance travel. Accordingly, various methods are being attempted to develop high-capacity, high-density secondary batteries.

[0003] A coiled electrode assembly can increase the capacity of a secondary battery by increasing the number of times the electrode is wound. However, as the number of times the electrode is wound increases, there is a risk of cracks occurring in the electrode plates at the rounded portion of the electrode assembly.

[0004] Stacked electrode assemblies can increase the capacity of secondary batteries by interposing a separator between the positive and negative electrodes and increasing the number of stacked electrodes. However, as the number of stacked electrodes increases, so does the number of electrode tabs. As the number of electrode tabs increases, the welding rate with the current collector decreases, limiting the ability to increase secondary battery capacity. Therefore, a new structure is needed to address this issue and increase secondary battery capacity.

[0005] 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.

[0006] An embodiment of the present invention provides a secondary battery capable of implementing high capacity and high density.

[0007] A secondary battery according to an embodiment of the present invention may include a plurality of electrode assemblies including a plurality of first electrode plates, a plurality of second electrode plates, and a plurality of separators respectively interposed between the first electrode plates and the second electrode plates; a case accommodating the electrode assemblies; a plurality of first current collector plates electrically connected to the first electrode plates; a plurality of second current collector plates electrically connected to the second electrode plates; a cap assembly having a first terminal portion and a second terminal portion electrically connected to the first current collector plates and the second current collector plates, respectively, and a cap plate coupled to the case.

[0008] The above case may have a rectangular parallelepiped shape.

[0009] The above electrode assembly may have a rectangular parallelepiped shape and may be in a stacked form in which the first electrode plate, the separator, and the second electrode plate are laminated.

[0010] The above electrode assemblies can be arranged so that their long sides face each other.

[0011] The separator may be placed at the outermost end of the electrode assembly.

[0012] An insulating tape may be attached to the outermost surface of the above electrode assembly.

[0013] The first collector plate and the second collector plate may be provided in a number corresponding to the number of electrode assemblies.

[0014] Each of the first electrode plates may include a pair of first substrate tabs spaced apart from each other.

[0015] Each of the second electrode plates may include a pair of second substrate tabs spaced apart from each other.

[0016] The above first substrate tab can be arranged at one end in the longitudinal direction of the electrode assembly.

[0017] The second substrate tab may be arranged at the other end in the longitudinal direction of the electrode assembly.

[0018] The first collector plate may be welded to the first substrate tab, and the second collector plate may be welded to the second substrate tab.

[0019] The above first collector plate and the above second collector plate can be welded by laser welding.

[0020] Each of the first and second collector plates may include a first plate surface and a second plate surface protruding toward the electrode assembly, and a connecting portion connecting the first and second plate surfaces between the first and second plate surfaces and protruding toward the case.

[0021] The first collector plate may have the first plate surface welded to an upper substrate tab among the first substrate tabs, and the second plate surface welded to a lower substrate tab among the first substrate tabs.

[0022] The second collector plate may be welded such that the first plate surface is welded to an upper substrate tab among the second substrate tabs, and the second plate surface is welded to a lower substrate tab among the second substrate tabs.

[0023] The first plate surface and the second plate surface may be provided with concave welding grooves.

[0024] The welding groove of the first current collector plate may be arranged toward the first substrate tab, and the welding groove of the second current collector plate may be arranged toward the second substrate tab.

[0025] The first substrate tab can be inserted into the welding groove of the first current collector plate, and the second substrate tab can be welded while being inserted into the welding groove of the second current collector plate.

[0026] The above welding groove can be positioned toward the case.

[0027] The above first terminal portion and the second terminal portion may each be provided in one unit.

[0028] According to an embodiment of the present invention, the weldability of the electrode assembly can be improved by providing a plurality of electrode assemblies and a current collector electrically connected to each electrode assembly. Accordingly, a high-capacity, high-density secondary battery can be provided.

[0029] FIG. 1 is a perspective view illustrating a secondary battery according to one embodiment of the present invention.

[0030] FIG. 2 is a perspective view illustrating an electrode assembly and a collector plate according to one embodiment of the present invention.

[0031] FIG. 3 is a perspective view illustrating an electrode assembly according to one embodiment of the present invention.

[0032] Figure 4 is a perspective view illustrating a current collector plate according to one embodiment of the present invention.

[0033] Fig. 5 is a side view of the collector plate according to Fig. 4.

[0034] The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The following embodiments may be modified in various ways, and the scope of the present invention is not limited to the embodiments described below. Rather, these embodiments are provided to more faithfully and completely explain the present disclosure and fully convey the spirit of the present invention to those skilled in the art.

[0035] In addition, in the drawings below, the thickness and size of each layer are exaggerated for convenience and clarity of explanation, and the same reference numerals in the drawings indicate the same elements. As used herein, the term "and / or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in this specification means not only when member A and member B are directly connected, but also when member C is interposed between member A and member B, so that member A and member B are indirectly connected.

[0036] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the present invention. As used herein, the singular forms "a," "an," and "the" may include the plural forms unless the context clearly dictates otherwise. Furthermore, as used herein, the words "comprise" and "include" and / or "comprising" and "including" specify the presence of stated features, numbers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, components, and / or groups thereof.

[0037] Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers, and / or portions, it is to be understood that these elements, components, regions, layers, and / or portions are not limited by these terms. These terms are only used to distinguish one element, component, region, layer, or portion from another. Accordingly, a first element, component, region, layer, or portion described below may refer to a second element, component, region, layer, or portion without departing from the teachings of the present invention.

[0038] Spatial terms such as "beneath," "below," "lower," "above," and "upper" may be used to facilitate understanding of one element or feature in a drawing relative to another. These spatial terms are intended to facilitate understanding of the present invention in various process states or usage states, and are not intended to limit the present invention. For example, if an element or feature in a drawing is flipped, an element or feature described as "beneath" or "below" becomes "above" or "above." Therefore, "below" is a concept encompassing "upper" or "below."

[0039] Hereinafter, a secondary battery according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0040] FIG. 1 is a perspective view illustrating a secondary battery according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating an electrode assembly and a current collector plate according to an embodiment of the present invention. FIG. 3 is a perspective view illustrating an electrode assembly according to an embodiment of the present invention. FIG. 4 is a perspective view illustrating a current collector plate according to an embodiment of the present invention. FIG. 5 is a side view of the current collector plate according to FIG. 4.

[0041] Referring to FIGS. 1 to 3, a secondary battery (10) according to one embodiment of the present invention may include a pair of electrode assemblies (100a, 100b), a case (200) that accommodates the electrode assemblies (100a, 100b), and a cap assembly (300) coupled to the case (200). For example, the secondary battery (10) may be a square battery in which the case (200) has a rectangular parallelepiped shape.

[0042] Referring to FIGS. 2 and 3, electrode assemblies (100a, 100b) may be provided as a pair. Each electrode assembly (100a, 100b) has the same structure. The electrode assemblies (100a, 100b) have a rectangular parallelepiped shape. One electrode assembly (100a, 100b) is arranged so that a relatively wide plate surface faces the relatively wide plate surface of the other electrode assembly (100a, 100b). The pair of electrode assemblies (100a, 100b) is provided so that they can be insulated from each other even when in contact with each other.

[0043] The electrode assembly (100a, 100b) is a stacked form of a plurality of unit laminates each comprising a first electrode plate and a second electrode plate in a thin plate or film shape, and a separator interposed therebetween. The electrode assembly (100a, 100b) may be arranged so that the long sides of the plurality of unit laminates are in contact with each other. An insulating material sheet (140) may be attached to the outside of the electrode assembly (100a, 100b) by an insulating tape (150) for insulation from the case (200). For example, the first electrode plate may be a negative electrode, and the second electrode plate may be a positive electrode. Or, the configuration may be reversed.

[0044] When the first electrode plate is a negative electrode plate, the first electrode plate may be formed by coating a first electrode current collector provided with a metal foil such as copper, a copper alloy, nickel, or a nickel alloy, with a first electrode active material such as graphite, carbon, or a mixture of graphite and silicon (Si). A first uncoated region, which is an area where the first electrode active material is not coated, may be formed on the first electrode plate. The first uncoated region may be cut into a certain shape to create first base tabs (110a, 110b). A plurality of first base tabs (110a, 110b) may be bent to one side and welded to the first current collector (330a, 330b). The first current collector (330a, 330b) may be electrically connected to the cap assembly (300). Since the electrode assemblies (100a, 100b) are provided as a pair, the first substrate tabs (110a, 110b) of each electrode assembly (100a, 100b) can be arranged in the same direction. In addition, since the electrode assemblies (100a, 100b) are provided as a pair, the first current collector plates (330a, 330b) can also be provided as a pair. For example, the first substrate tabs (110a, 110b) can be configured as two groups. That is, two first substrate tabs (110a, 110b) can be provided for each first electrode plate. The two first substrate tabs (110a, 110b) can be spaced apart from each other by a predetermined distance. Therefore, when a plurality of first electrode plates are laminated, the electrode assembly (100a, 100b) has two groups of first substrate tabs (110a, 110b) spaced apart from each other as shown in FIG. 3. The two groups of first substrate tabs (110a, 110b) are arranged on one side of the length direction of the electrode assembly (100a, 100b). For convenience, in FIG. 3, the upper first substrate tab group (110a) is referred to as the first upper group, and the lower first substrate tab group (110b) is referred to as the first lower group.

[0045] When the second electrode plate is a positive electrode plate, the second electrode plate may be formed by coating a second electrode current collector provided with a metal foil such as aluminum or an aluminum alloy with a second electrode active material such as a transition metal oxide such as lithium cobalt oxide (LCO), NCM (nickel cobalt manganese, LNMO), NCA (nickel cobalt aluminum), lithium iron phosphate (LFP), and NMx (cobalt-free lithium nickel manganese). A second uncoated region, which is an area where the second electrode active material is not coated, may be formed on the second electrode plate. The second uncoated region may be cut into a certain shape to form second base tabs (120a, 120b). A plurality of second base tabs (120a, 120b) may be bent to one side and welded to the second current collector plate (340a, 340b). The second current collector plates (340a, 340b) may be electrically connected to the cap assembly (300). Since the electrode assemblies (100a, 100b) are provided as a pair, the second substrate tabs (120a, 120b) of each electrode assembly (100a, 100b) may all be arranged in the same direction. In addition, since the electrode assemblies (100a, 100b) are provided as a pair, the second current collector plates (340a, 340b) may also be provided as a pair. For example, the second substrate tabs (120a, 120b) may be configured as two groups. That is, two second substrate tabs (120a, 120b) may be provided for each second electrode plate. The two second substrate tabs (120a, 120b) may be spaced apart from each other by a predetermined distance. Therefore, when a plurality of second electrode plates are stacked, the electrode assembly (100a, 100b) has two groups of second substrate tabs (120a, 120b) spaced apart from each other as shown in Fig. 3. The two groups of second substrate tabs (120a, 120b) are arranged on the other side of the electrode assembly (100a, 100b) in the longitudinal direction. Here, the arrangement direction of the second substrate tabs (120a, 120b) is opposite to the arrangement direction of the first substrate tabs (110a, 110b).For convenience, in FIG. 3, the upper second substrate tab group (120a) is referred to as the second upper group, and the lower second substrate tab group (120b) is referred to as the second lower group.

[0046] A separator is positioned between the first and second electrode plates to prevent short circuits and enable the movement of lithium ions. For example, the separator may include a polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. However, the separator is not limited to the aforementioned materials.

[0047] The electrode assembly (100a, 100b) of the above-described structure may be accommodated in a case (200) together with an electrolyte. In some manufacturing processes of the secondary battery (10), the electrode assembly (100a, 100b) is inserted into the case (200) (this will be described later). In some examples, the electrolyte may include a lithium salt such as LiPF6, LiBF4 in an organic solvent such as EC (ethylene carbonate), PC (propylene carbonate), DEC (diethyl carbonate), EMC (ethylmethyl carbonate), or DMC (dimethyl carbonate). In addition, the electrolyte may be liquid or gel-like. In some examples, when an inorganic solid electrolyte is used, the electrolyte may be omitted.

[0048] Referring to FIG. 1, the case (200) has a roughly rectangular box shape, and the upper part in the longitudinal direction may be opened and an accommodation space may be formed inside. The electrode assembly (100a, 100b) and the electrolyte may be accommodated inside the case (200) through the opened upper part. Some components of the cap assembly (300) may be exposed to the outside of the case (200), and some components may be accommodated inside the case (200). The case (200) may be composed of a rectangular bottom surface (210) and four side surfaces connected to the bottom surface (210). Among the side surfaces, a side with a relatively large area is defined as a long side portion (220), and a side with a relatively small area is defined as a short side portion (230). For example, the electrode assemblies (100a, 100b) may be arranged so that the plate surface faces the long side portion (220). With the electrode assembly (100a, 100b) accommodated in the case (200), the cap assembly (300) is coupled to the case (200) and electrically connected to the electrode assembly (100a, 100b).

[0049] Referring to FIGS. 2, 4 and 5, the cap assembly (300) may include a cap plate (310) coupled to the case (200), a plurality of insulating members, a first collector plate (330a, 330b) and a second collector plate (340a, 340b), a first terminal portion (350) and a second terminal portion (360).

[0050] Referring to FIGS. 1 and 2, the cap plate (310) may be formed in a substantially rectangular plate shape and made of the same material as the case (200). The cap plate (310) may be provided with terminal holes for connection with the first terminal portion (350) and the second terminal portion (360), a liquid injection hole (314), a vent hole for connection with the vent (316), and the like. In order to insulate the cap plate (310) and the electrode assembly (100a, 100b), a plurality of insulating members not shown in the drawings, such as an insulating plate (320), may be provided.

[0051] Referring to FIGS. 4 and 5, the first collector plates (330a, 330b) electrically connect the first electrode plate, which is a negative electrode plate, and the first terminal portion (350). For this purpose, the first collector plates (330a, 330b) may be made of the same material as the first electrode plate. For example, the first collector plates (330a, 330b) may be electrically connected to the first substrate tabs (110a, 110b) of the first electrode plate by laser welding. For welding, the first substrate tabs (110a, 110b) may be brought together to one side, and then the first collector plates (330a, 330b) may be placed on the first substrate tabs (110a, 110b) and welded. The first collector plates (330a, 330b) are provided as a pair.

[0052] The first collector plates (330a, 330b) are provided as a pair because they must be electrically connected to the two electrode assemblies (100a, 100b), respectively. The pair of first collector plates (330a, 330b) have the same structure. One first collector plate (330a, 330b) can be arranged parallel to the other first collector plate (330a, 330b). That is, the pair of first collector plates (330a, 330b) can be arranged on the same line. However, the pair of first collector plates (330a, 330b) can be spaced apart from each other so as not to contact each other.

[0053] The first collector plate (330a, 330b) may have a plate shape that is approximately rectangular when viewed from the front. The first collector plate (330a, 330b) may be made by bending a rectangular plate multiple times. The first collector plate (330a, 330b) may include a first plate surface (332) electrically connected to one of the first substrate tab groups (110a in FIG. 3), a second plate surface (334) electrically connected to another of the first substrate tab groups (110b in FIG. 3), and a connecting portion (336) disposed between the first plate surface (332) and the second plate surface (334). The connecting portion (336) may be provided not only between the first plate surface (332) and the second plate surface (334), but also at one end of the first plate surface (332) and one end of the second plate surface (334). The first plate surface (332) and the second plate surface (334) may each be provided with a welding groove (338) for welding with the first substrate tab.

[0054] The first plate surface (332) can be electrically connected to the first substrate tab (first upper group, 110a in FIG. 3) on the upper side based on FIG. 3. The second plate surface (334) can be electrically connected to the first substrate tab (first lower group, 110b in FIG. 3) on the lower side based on FIG. 3. Since the first substrate tab (110a, 110b) groups of the electrode assemblies (100a, 100b) are spaced apart from each other, the first plate surface (332) and the second plate surface (334) are also arranged to be spaced apart from each other. The first plate surface (332) and the second plate surface (334) are perpendicular to the cap plate (310). To this end, a connecting portion (336) is provided between the first plate surface (332) and the second plate surface (334) to connect them.

[0055] The connecting portion (336) is provided at a step from the first plate surface (332) and the second plate surface (334). The connecting portion (336) corresponds to a position between the first substrate tabs (110a, 110b) group. The connecting portion (336) protrudes away from the electrode assembly (100a, 100b) so as not to come into contact with the first substrate tabs (110a, 110b) or the electrode assembly (100a, 100b). That is, the connecting portion (336) protrudes toward the short side (230) of the case (200). The connecting portion (336) may be provided in a 'ㄷ' shape when viewed from the side. Based on the connecting portion (336), the first plate surface (332) is connected to the upper side, and the second plate surface (334) is connected to the lower side. In addition, the connecting portion (336) may be provided at the upper end of the first plate surface (332) and the lower end of the second plate surface (334), respectively. The connecting portion (336) at the upper end of the first plate surface (332) may have the same shape as the connecting portion at the center. The end of the connecting portion (336) at the upper end may be electrically connected to the first terminal portion (350) by a conductive plate or the like, which is not shown in the drawing. The connecting portion (336) at the lower end of the second plate surface (334) may be vertically bent from the second plate surface (334) and then vertically bent downward again to prevent contact with the lower first substrate tab (110b) group. That is, the end of the connecting portion (336) at the lower end of the second plate surface (334) extends parallel to the first plate surface (332) or the second plate surface (334). Therefore, when the first collector plate (330a, 330b) is viewed from the side, it can be seen that the first plate surface (332) and the second plate surface (334) protrude toward the electrode assembly (100a, 100b), and the connecting portion (336) protrudes toward the short side (230) of the case (200) (see FIG. 5).

[0056] Meanwhile, a welding groove (338) may be provided on the first plate surface (332) and the second plate surface (334). The welding groove (338) is a groove formed concavely from the first plate surface (332) and the second plate surface (334) facing the short side (230) of the case (200) toward the electrode assembly (100a, 100b). Although the welding groove (338) is illustrated in a rectangular shape in FIG. 4, it is not limited to the illustrated shape. When welding the first current collector plate (330a, 330b) and the first substrate tab (110a, 110b), welding is performed in the direction (arrow direction in FIG. 5) from the welding groove (338) toward the first substrate tab (110a, 110b). The area where the welding groove (338) is provided is thinner than other areas. Accordingly, the adhesion with the first base tab (110a, 110b) can be improved and the welding time can be shortened by the welding groove (338). Alternatively, although not shown in the drawing, the welding groove (338) may be provided in the direction of the first base tab. In this case, the welding groove (338) may serve to temporarily secure the first base tab (110a, 110b) prior to welding.

[0057] The second collector plates (340a, 340b) are arranged symmetrically with the first collector plates (330a, 330b) and are electrically connected to the second electrode plate (120). For this purpose, the second collector plates (340a, 340b) may be made of the same material as the second substrate tabs (120a, 120b) of the second electrode plate (120). For welding, the second substrate tabs (120a, 120b) may be brought together to one side, and then the second collector plates (340a, 340b) may be placed on the second substrate tabs (120a, 120b) and welded. Since the second collector plates (340a, 340b) have the same number and structure as the first collector plates (330a, 330b), a detailed description thereof will be omitted.

[0058] As described above, the structure in which the first collector plate (330a, 330b) and the second collector plate (340a, 340b) have a plate surface protruding toward the case (200) and the substrate tabs (110a, 110b, 120a, 120b) are surface-to-surface laser welded to the protruding plate surface can be defined as LPW (Laser Plate Welding).

[0059] The first terminal portion (350) may include a first terminal pin (352) and a first terminal plate (354). The first terminal plate (354) may be insulated from the cap plate (310) by an insulating member (328). The first terminal pin (352) is electrically connected to the first current collector plate (330a, 330b), thereby being electrically connected to the first electrode plate (110) of the electrode assembly (100a, 100b). Even if a plurality of first current collector plates (330a, 330b) are provided, only one first terminal portion (350) is provided.

[0060] The second terminal portion (360) may include a second terminal pin (362), a second terminal plate (364), and a conductive plate (366). The second terminal portion (360) is arranged symmetrically with the first terminal portion (350). The conductive plate (366) electrically connects the second terminal plate (364), which is electrically connected to the second terminal pin (362), and the cap plate (310). Therefore, the cap plate (310) is connected to the second collector plates (340a, 340b) by the second terminal portion (360), and thus can be electrically connected to the second electrode plate (120). Therefore, the cap plate (310) has the same positive polarity as the second collector plates (340a, 340b), and the case (200) welded to the cap plate (310) also has positive polarity. Even if a plurality of second collector plates (340a, 340b) are provided, only one second terminal section (360) is provided.

[0061] In the above-described embodiment, an embodiment in which two electrode assemblies are provided and two first and second collector plates corresponding thereto are also provided has been described. However, the number of electrode assemblies and collector plates may vary depending on the size of the case or the target capacity of the secondary battery. If the case is sufficiently large, multiple electrode assemblies may be provided. The number of first and second collector plates may also be provided to correspond to the number of electrode assemblies.

[0062] As described above, according to an embodiment of the present invention, the weldability of the electrode assembly can be improved by providing a plurality of electrode assemblies and a current collector electrically connected to each electrode assembly. Accordingly, a high-capacity, high-density secondary battery can be provided.

[0063] The above description is only one embodiment for carrying out the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, it will be said that the technical spirit of the present invention exists to the extent that anyone with ordinary skill in the art to which the present invention pertains can make various modifications without departing from the gist of the present invention.

Claims

1. A plurality of electrode assemblies comprising a plurality of first electrode plates, a plurality of second electrode plates, and a plurality of separators respectively interposed between the first electrode plates and the second electrode plates; A case accommodating the above electrode assembly; A plurality of first current collector plates electrically connected to the first electrode plate; A plurality of second collector plates electrically connected to the second electrode plate; A secondary battery comprising a cap assembly having a first terminal portion and a second terminal portion electrically connected to the first collector plate and the second collector plate, respectively, and a cap plate coupled to the case.

2. In paragraph 1, A secondary battery, wherein the electrode assembly has a rectangular parallelepiped shape and the first electrode plate, the separator, and the second electrode plate are laminated in a stacked form.

3. In paragraph 2, A secondary battery in which the electrode assemblies are arranged so that their long sides face each other.

4. In paragraph 3, A secondary battery, wherein the separator is arranged on the outermost surface of the electrode assembly.

5. In paragraph 3, A secondary battery, wherein insulating tape is attached to the outermost surface of the electrode assembly.

6. In paragraph 3, A secondary battery, wherein the first collector plate and the second collector plate are provided in a number corresponding to the number of electrode assemblies.

7. In paragraph 6, A secondary battery, wherein each of the first electrode plates includes a pair of first substrate tabs spaced apart from each other.

8. In paragraph 7, A secondary battery, wherein each of the second electrode plates includes a pair of second substrate tabs spaced apart from each other.

9. In paragraph 8, A secondary battery, wherein the first substrate tab is arranged at one end in the longitudinal direction of the electrode assembly.

10. In paragraph 9, A secondary battery, wherein the second substrate tab is arranged at the other end in the longitudinal direction of the electrode assembly.

11. In Article 10, A secondary battery, wherein the first current collector plate is welded to the first substrate tab, and the second current collector plate is welded to the second substrate tab.

12. In paragraph 11, A secondary battery, wherein the first collector plate and the second collector plate are welded by laser welding.

13. In paragraph 12, A secondary battery, wherein each of the first and second collector plates includes a first plate surface and a second plate surface protruding toward the electrode assembly, and a connecting portion connecting the first and second plate surfaces between the first and second plate surfaces and protruding toward the case.

14. In paragraph 13, The above first collector plate is a secondary battery, wherein the first plate surface is welded to an upper substrate tab among the first substrate tabs, and the second plate surface is welded to a lower substrate tab among the first substrate tabs.

15. In paragraph 14, The second collector plate is a secondary battery, wherein the first plate surface is welded to an upper substrate tab among the second substrate tabs, and the second plate surface is welded to a lower substrate tab among the second substrate tabs.

16. In clause 14 or 15, A secondary battery, wherein the first plate surface and the second plate surface have concave welding grooves.

17. In paragraph 16, A secondary battery, wherein the welding groove of the first current collector plate is arranged toward the first substrate tab, and the welding groove of the second current collector plate is arranged toward the second substrate tab.

18. In paragraph 17, A secondary battery, wherein the first substrate tab is inserted into the welding groove of the first current collector plate, and the second substrate tab is welded while being inserted into the welding groove of the second current collector plate.

19. In paragraph 16, A secondary battery, wherein the above welding groove is positioned toward the case.

20. In paragraph 7, A secondary battery, wherein each of the first terminal portion and the second terminal portion is provided in one piece.

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