Electrode plate, electrode assembly, and secondary battery including the same

Abstract

To provide an electrode plate, an electrode assembly, and a secondary battery including the same, that can achieve electric conduction between electrode plates that are adjacent to each other.SOLUTION: An electrode plate according to the present invention includes a base layer, a current collecting layer including a first conductive layer and a second conductive layer existing on upper and lower surfaces of the base layer, and an electrode plate layer existing on at least one surface of the current collecting layer. The current collecting layer includes a current collecting part having the electrode plate layer present on at least one surface thereof, an extension part extending to the outside from the current collecting part, and a bent part coupled to the extension part and bent twice or more so that the first conductive layer comes into contact with the second conductive layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrode plate, an electrode assembly, and a secondary battery including the same.

Background Art

[0002] Although rechargeable batteries are manufactured in various shapes, among them, a pouch battery includes an electrode assembly in which an insulator separator is interposed between a positive electrode plate and a negative electrode plate, and a thin flexible pouch in which the electrode assembly is incorporated. At this time, the pouch houses the electrode assembly in an inner space.

[0003] The electrode assembly of a secondary battery is largely classified into a winding type and a stacking type according to its structure. The stacking type has high structural safety and excellent space utilization, and is widely applied to small, medium, and large sizes. A secondary battery of the stacking type is a laminate of a plurality of electrode plates and a separator.

[0004] The current collectors applied to the electrodes of a secondary battery, that is, the positive electrode and the negative electrode, may be usually thin films of electrically conductive copper, aluminum, Ni, SUS, etc. For example, in the case of a commercialized lithium-ion battery, a copper foil current collector is used for the negative electrode and an aluminum foil current collector is used for the positive electrode.

[0005] Recently, instead of manufacturing the entire current collector layer with copper or aluminum in order to reduce the manufacturing cost and weight of a secondary battery, a current collector layer in which a metal film is coated on both sides of a resin is also applied.

[0006] In the case of welding a plurality of base material taps in a conventional manner with a stack electrode plate using the resin-metal composite base material as described above, there is a problem that the entire electrode plate cannot be utilized or is not electrically activated.

[0007] The resin-metal composite substrate has metal films located on both sides of the resin sheet. Since the resin has low electrical conductivity, it is difficult to electrically connect both sides to each other. In particular, in a stacked electrode plate using a plurality of electrode plates, the plain portions are joined to each other and welded to the electrode terminals. However, there is a problem that the metal films on both sides are not energized with each other, and only the surfaces on one side are in contact with each other and welding cannot be performed.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention is for overcoming the above-described conventional problems. The object of the present invention is to provide an electrode plate, an electrode assembly, and a secondary battery including the same that can achieve energization between adjacent electrode plates.

[0009] However, the technical problems to be solved by the present invention are not limited to the above-described problems, and other problems not mentioned should be clearly understood by those skilled in the art from the description of the invention described below.

Means for Solving the Problems

[0010] An electrode plate according to an embodiment of the present invention for solving the above-described technical problems includes a base layer, a current collecting layer including a first conductive layer and a second conductive layer located on the upper and lower surfaces of the base layer, respectively, and an electrode plate layer located on at least one surface of the current collecting layer. The current collecting layer includes a current collecting portion on which the electrode plate layer is located on at least one surface, an extension portion extending from the current collecting portion to the outside, and a bent portion that is connected to the extension portion and is bent two or more times so that the first conductive layer contacts the second conductive layer.

[0011] The base layer may include polyethylene terephthalate (PET).

[0012] The base layer may include one or more selected from polyamide, polyimide, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polyethylene propylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride-based, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin, derivatives of the aforementioned materials, cross-linked products of the aforementioned materials, and copolymers of the aforementioned materials.

[0013] The base layer further includes an additive, and the additive may include one or more of a metal material and an inorganic non-metallic material.

[0014] The first conductive layer and the second conductive layer may include aluminum.

[0015] The first conductive layer and the second conductive layer may include one or more of a metal material, a carbon-based conductive material, and a conductive polymer material.

[0016] The bent portion may have a jelly roll shape.

[0017] The electrode assembly according to an embodiment of the present invention includes a plurality of electrode plates and a separator, and is an electrode assembly in which the plurality of electrode plates are laminated with the separator interposed therebetween. Each of the plurality of electrode plates includes a base layer, a current collecting layer including a first conductive layer and a second conductive layer respectively located on the upper and lower surfaces of the base layer, and a plate layer disposed on a part of the current collecting layer. The current collecting layer includes a current collecting portion where the plate layer is located on at least one surface, an extension portion extending outward from the current collecting portion, and a bent portion connected to the extension portion and bent two or more times so that the first conductive layer contacts the second conductive layer.

[0018] The current collecting layers included in each of the plurality of electrode plates may be such that the bent portions adjacent to each other are coupled to each other in the vertical direction.

[0019] The plurality of electrode plates may include a first electrode plate and a second electrode plate.

[0020] The base layer may include polyethylene terephthalate (PET).

[0021] The base layer may include one or more selected from the group consisting of polyamide, polyimide, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polyethylene propylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride-based, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin, derivatives of the foregoing materials, cross-linked products of the foregoing materials, and copolymers of the foregoing materials.

[0022] The base layer may further include an additive, and the additive may include one or more of a metal material and an inorganic non-metallic material.

[0023] The first conductive layer and the second conductive layer may include aluminum.

[0024] The first conductive layer and the second conductive layer may include one or more of a metal material, a carbon-based conductive material, and a conductive polymer material.

[0025] The bent portion may have a jelly roll shape.

[0026] A secondary battery according to an embodiment of the present invention includes an electrode assembly and a case that houses the electrode assembly.

Advantages of the Invention

[0027] According to the present invention, the electrode plate included in the electrode assembly includes a current collecting layer including a bent portion. Therefore, the first conductive layer of any one current collecting layer is connected to the second conductive layer.

[0028] In addition, by connecting the bent portions of the plurality of electrode plates to each other, each of the first electrode plate and the second electrode plate can be electrically connected in the electrode assembly.

[0029] As described above, the electrode assembly according to an embodiment of the present invention does not need to perform a current conduction process in which a foil is additionally folded and inserted one by one between the electrode plates as in the prior art. Therefore, not only can the manufacturing time be shortened, but also the manufacturing cost can be reduced.

Brief Description of the Drawings

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to better understand the technical idea of the present invention together with the detailed description of the invention to be described later. Therefore, the present invention should not be construed as being limited only to the matters described in these drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should be based on the principle that he can appropriately define the concept of the terms in order to explain his own invention in the best way, and should be construed in a meaning and concept that conforms to the technical idea of the present invention. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention, and do not represent all of the technical ideas of the present invention. At the time of this application, there may be various equivalents and modifications that can replace these.

[0032] Also, as used in this specification, "comprise", "include" and / or "comprising", "including" are used to specify the presence of the recited shape, number, step, operation, member, element and / or group thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements and / or groups.

[0033] Also, for the understanding of the invention, the accompanying drawings are not illustrated at actual scale, and the dimensions of some components may be exaggerated. Also, the same reference numerals are given to the same components in different embodiments.

[0034] The reference that two objects to be compared are "identical" means "substantially identical". Therefore, substantially identical can include cases with deviations regarded as low levels in the art, for example, deviations within 5%. Also, that any parameter is uniform in a predetermined region means that it is uniform from an average perspective.

[0035] Although terms such as first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are merely used to distinguish one component from another, and without a particular negative description, the first component may, of course, be the second component.

[0036] Throughout the specification, unless there is a particular negative description, each component may be in the singular or plural.

[0037] The statement that any configuration is arranged "above (or below)" a component or "on (or under)" a component means that not only is any configuration arranged in contact with the upper surface (or lower surface) of the said component, but other configurations may also be interposed between the said component and any configuration arranged "above (or below)" the said component.

[0038] Also, when a certain component is described as being "on", "connected to", or "coupled to" another component, it should be understood that the said components may be directly connected or joined to each other, but other components may be "interposed" between the components, or each component may be "connected", "coupled", or "joined" through other components.

[0039] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Also, when describing embodiments of the present disclosure, the use of "can also" relates to "one or more embodiments of the present disclosure". Expressions such as "one or more" and "one or more" before a list of elements modify the entire list of elements and not the individual elements of the list.

[0040] Throughout the specification, when referring to "A and / or B", this means A, B, or A and B, unless otherwise stated to the contrary, and when referring to "C to D", this means greater than or equal to C and less than or equal to D, unless otherwise stated to the contrary.

[0041] When constructs 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 among A, B, and C" are used to specify a list of elements A, B, and C, the construct can refer to any and all suitable combinations.

[0042] The term "use" can be regarded as a synonym for the term "utilize". As used herein, terms such as "substantially", "approximately", and similar terms are used as terms of approximation rather than degree, and are for taking into account the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0043] As used herein, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, drawing layer, or cross-section from other elements, components, regions, drawing layers, or cross-sections. Thus, the first element, component, region, layer, or section discussed below is not deviated from the teachings of the exemplary embodiments and can be named the second element, component, region, layer, or section.

[0044] As shown in the drawings, for the sake of ease of explanation, spatial relative terms such as "beneath", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship between an element or feature and other element(s) or feature(s). The spatially relative position is to be understood to encompass different directions of the device during use or operation in addition to the direction depicted in the figures. For example, when the device in the drawing is covered, an element described as "below" or "beneath" another element is understood to be "above" or "upper" of the other element. Thus, the term "below" can encompass both the up and down directions.

[0045] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure.

[0046] Before describing an electrode plate according to an embodiment of the present invention with reference to the accompanying drawings below, a secondary battery including the electrode plate will be described in detail.

[0047] FIG. 1 is a perspective view showing an electrode plate according to an embodiment of the present invention and a secondary battery in which an electrode assembly including the same can be provided, and FIG. 2 is a cross-sectional view showing a state in which a plurality of electrode plates are coupled to each other.

[0048] Referring to FIGS. 1 and 2, the secondary battery 100 may include an electrode assembly 200 and a case 300.

[0049] The electrode assembly 200 includes a plurality of electrode plates 210, 220 and a separator 230. More specifically, the plurality of electrode plates 210, 220 may include a first electrode plate 210 and a second electrode plate 220.

[0050] Such an electrode assembly 200 may be in a form in which a laminate including the first electrode plate 210, the second electrode plate 220, and the separator 230 is repeatedly wound or laminated.

[0051] For example, the electrode assembly 200 may be a laminated type in which the electrode plates 210, 220 are arranged to be laminated in a plurality of layers. Alternatively, the electrode assembly 200 may be a jelly-roll type that is repeatedly wound. In the present invention, the electrode assembly 200 being of the laminated type will be described as an example.

[0052] On the other hand, in the manufacturing process of the laminated type electrode assembly 200, it is common to perform a primary lamination process and a secondary process.

[0053] In the primary lamination process, a full cathode and a full anode can be laminated. Here, the full cathode may be, for example, the remaining ones among the plurality of first electrode plates 210 excluding the outermost first electrode plate 210A. And the full anode may be the second electrode plate 220.

[0054] In the secondary lamination process, a half cathode can be laminated on one or more sides of the outermost sides with respect to the lamination direction. Here, the half cathode may be the outermost first electrode plate 210A among the first electrode plates 210.

[0055] In terms of cost, FIG. 2 illustrates an electrode assembly 200 in which a half cathode is laminated on the upper outermost periphery of the electrode assembly 200. However, it is also possible that half cathodes are laminated on each of the upper outermost periphery and both side outermost peripheries of the electrode assembly 200.

[0056] Here, the double-sided cathode and the double-sided anode have active materials coated on both sides of the base material, and the half cathode has a current collector layer with a current collector layer disposed only on one side. Here, the current collector layer may be an active material layer. A detailed description of such a double-sided cathode, double-sided anode, and half cathode will be omitted.

[0057] The separator 230 may be interposed between the first electrode plate 210 and the second electrode plate 220. The separator 230 prevents short circuit between the first electrode plate 210 and the second electrode plate 220 and enables the movement of lithium ions. For this purpose, the separator 230 may be relatively larger in size than the current collector layer.

[0058] As an example, the material of the separator 230 may be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene, but is not limited thereto.

[0059] Such a separator 230 may be cut into unit lengths and disposed between the first electrode plate 210 and the second electrode plate 220, or a single separator 230 in the form of a ribbon may be disposed between the first electrode plate 210 and the second electrode plate 220 in a zigzag form. Different from this, the separator 230 may also be provided so as to wind in one direction between the first electrode plate 210 and the second electrode plate 220.

[0060] In this way, the arrangement form of the separator 230 is not limited to a specific form. However, in this embodiment, the description will be limited to the case where the separator 230 is cut into unit lengths and disposed between the first electrode plate 210 and the second electrode plate 220.

[0061] The case 300 can accommodate the electrode assembly 200. The aforementioned electrode assembly 200 is accommodated in the case 300 together with the electrolytic solution.

[0062] The case 300 as described above may be any one of a pouch type, a cylindrical type, and a rectangular type. The pouch-type case 300 may be manufactured by bending plate-like exterior materials to face each other and then pressing or drawing one surface so as to include a recess on one surface.

[0063] The electrode assembly 200 is accommodated in a recess (not shown). A sealing portion 310 is provided at the outer peripheral edge of the recess, and the sealing portion 310 is sealed by a method such as heat fusion in a state where the electrode assembly 200 is accommodated in the recess.

[0064] On the other hand, among the plurality of electrode plates, the aforementioned first electrode plate 210 may be a negative electrode, the second electrode plate 220 may be a positive electrode, or vice versa. The first electrode plate 210 and the second electrode plate 220 can be electrically connected to the outside of the secondary battery 100 through the plate-like terminal 250. And the insulating tape 240 can be attached to the portion where the plate-like terminal 250 contacts the case 300. The insulating tape 240 can prevent the plate-like terminal 250 and the case 300 from being energized.

[0065] Hereinafter, with reference to the drawings, the electrode assembly 200 according to an embodiment of the present invention will be described in more detail.

[0066] FIG. 2 is a cross-sectional view showing a state in which a plurality of electrode plates are joined to each other, and FIG. 3 is a perspective view showing an extraction of the electrode plates from the secondary battery of FIG. 1.

[0067] Referring to FIGS. 2 and 3, as described above, the electrode assembly 200 according to an embodiment of the present invention includes a plurality of electrode plates 210 and 220, and each of the plurality of electrode plates 210 and 220 includes a current collecting layer 201 and a plate layer 202 disposed on a part of the current collecting layer 201. Here, since the plate layer 202 may be an electrode active material layer used in a general secondary battery, a detailed description thereof will be omitted.

[0068] Based on the internal structure, the current collecting layer 201 includes a base layer E, a first conductive layer F1 and a second conductive layer F2 located on each of the upper and lower surfaces of the base layer E.

[0069] The base layer E may include, for example, polyethylene terephthalate (PET).

[0070] Alternatively, the base layer E may include, for example, one or more of polyamide, polyimide, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polyethylene propylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride-based, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin, derivatives of the foregoing materials, cross-linked bodies of the foregoing materials, and copolymers of the foregoing materials.

[0071] On the other hand, the base layer E may further include an additive. The additive may include one or more of a metal material and an inorganic non-metal material.

[0072] For example, the metal material additive may be one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, iron, iron alloy, silver, and silver alloy.

[0073] And the inorganic non-metallic material additive is, for example, one or more of carbon-based materials, aluminum oxide, silicon dioxide, silicon nitride, silicon carbide, boron nitride, silicate, and titanium oxide, and is, for example, one or more of glass materials, ceramic materials, and ceramic composite materials. The carbon-based material additive may be, for example, one or more of graphite, superconducting carbon, acetylene black, carbon black, ketjen black, carbon dot, carbon nanotube, graphene, and carbon nanofiber.

[0074] On the other hand, the additive may further include a carbon-based material coated with a metal material. For example, it may be one or more of graphite powder coated with nickel and carbon fiber coated with nickel.

[0075] On the other hand, the first conductive layer F1 and the second conductive layer F2 may contain aluminum. More specifically, the first conductive layer F1 and the second conductive layer F2 may contain one or more of a metal material, a carbon-based conductive material, and a conductive polymer material.

[0076] On the other hand, the above-described current collector layer 201 may include a current collecting portion 201a, an extension portion 201b, and a bent portion 201c based on the external shape.

[0077] The current collecting portion 201a may have a polar plate layer 202 coated on at least one surface. The current collecting portion 201a may be, for example, in a rectangular plate shape. For example, as shown in FIG. 3, the polar plate layer 202 may be coated on the remaining portion excluding the peripheral region of the current collecting portion 201a. At this time, the peripheral region of the current collecting portion 201a may be a plain portion where the polar plate layer 202 is not coated.

[0078] In contrast, the electrode plate layer 202 can also be applied to the entire current collector portion 201a. At this time, the current collector portion 201a does not include a plain portion, and the extension portion 201b described later may be a plain portion.

[0079] The extension portion 201b is connected to the current collector portion 201a and extends outward from the current collector portion 201a. The extension portion 201b may be, for example, in a ribbon shape.

[0080] The bent portion 201c is connected to the extension portion 201b. The bent portion 201c is bent two or more times so that the first conductive layer F1 contacts the second conductive layer F2. For the sake of convenience of explanation, FIG. 2 shows that the bent portion 201c is bent twice. The overall shape of the bent portion 201c may be a jelly roll shape that is repeatedly bent in one direction.

[0081] On the other hand, as described above, the plurality of electrode plates 210 and 220 include the first electrode plate 210 and the second electrode plate 220, and the current collector layers 201 of the first electrode plate 210 and the second electrode plate 220 each include an extension portion 201b and a bent portion 201c.

[0082] The bent portions 201c included in each of the plurality of electrode plates 210 and 220 may be joined to each other in the vertical direction.

[0083] More specifically, when the electrode assembly 200 is of a stacked type, the first electrode plate 210 and the second electrode plate 220 may be alternately stacked with each other with the separator 230 interposed therebetween. There may be a plurality of the first electrode plates 210 and the second electrode plates 220.

[0084] In the drawings, three of each of the first electrode plate 210 and the second electrode plate 220 are shown, but the present invention is not limited thereto, and the number of the first electrode plate 210 and the second electrode plate 220 may be varied according to the design of the secondary battery 100.

[0085] In the electrode assembly 200 according to an embodiment of the present invention, the bent portions 201c of the first electrode plate 210 are arranged side by side in the vertical direction, and the bent portions 201c of the second electrode plate 220 are arranged side by side in the vertical direction. Although not shown, the bent portions 201c of the first electrode plate 210 may be spaced apart from the bent portions 201c of the second electrode plate 220 in the left - right direction.

[0086] And since the extension portions 201b connect the current - collecting portions 201a and the bent portions 201c, the extension portions 201b of the first electrode plate 210 are arranged side by side in the vertical direction, and the extension portions 201b of the second electrode plate 220 are arranged side by side in the vertical direction.

[0087] On the other hand, the bent portions 201c as described above may be joined by a welding method. For example, a plurality of bent portions 201c may be grouped together and joined by a welding method such as laser, resistance welding, and ultrasonic welding.

[0088] On the other hand, the length of the extension portion 201b may be relatively shorter than the length of the bent portion 201c. On the contrary, the length of the extension portion 201b may be relatively longer than the length of the bent portion 201c. Since the length of the bent portion 201c and the length of the extension portion 201b can be varied according to the design of the electrode assembly 200, they are not limited to a specific length.

[0089] In the aforementioned electrode assembly 200, since the bent portion 201c is bent two or more times, the extension portions 201b are not welded to each other, and the bent portions 201c are welded to each other, so that the plurality of electrode plates 210 and 220 can be energized. However, additionally, the extension portions 201b can be welded to each other to improve the bonding force, but it is not limited thereto.

[0090] The manufacturing process of the electrode assembly 200 according to an embodiment of the present invention as described above will be described with reference to the drawings.

[0091] FIGS. 4 to 6 are cross - sectional views sequentially showing the process in which the electrode plates are joined to each other. FIG. 4 is a cross - sectional view showing a state in which the electrode plates are arranged side by side in the vertical direction.

[0092] Referring to FIG. 4, the first electrode plate 210 and the second electrode plate 220 are laminated. The first electrode plate 210 and the second electrode plate 220 may be sequentially laminated with the separation membrane 230 interposed therebetween.

[0093] FIG. 5 is a cross-sectional view showing the process in which each bent portion of the current collecting layer is welded by ultrasonic welding.

[0094] Referring to FIG. 5, the plurality of second electrode plates 220 can weld the bent portions 201c to each other by a welding horn T used for ultrasonic welding. At this time, the first conductive layer F1 and the second conductive layer F2 of any one current collecting layer 201 can be electrically connected to each other. Therefore, even if the extension portions 201b are not welded to each other, the plurality of second electrode plates 220 can be electrically connected to each other only by welding the bent portions 201c. Although not shown, the plurality of first electrode plates 210 can also be electrically connected to each other.

[0095] FIG. 6 is a cross-sectional view showing the process in which each extension portion of the current collecting layer is welded by ultrasonic welding.

[0096] Referring to FIG. 6, the plurality of second electrode plates 220 can weld the extension portions 201b to each other by a welding horn T used for ultrasonic welding. At this time, the second conductive layer F2 of any one current collecting layer 201 and the first conductive layer F1 of the current collecting layer 201 adjacent thereto can be electrically connected to each other. By welding the extension portions 201b to each other in this way, the bonding force of the plurality of second electrode plates 220 can be further improved.

[0097] Here, as described above, the process of welding the extension portions 201b to each other can be selectively performed.

[0098] On the one hand, as shown in FIG. 7, it is also possible to press the extension part 201b with the roller R before welding the extension part 201b. Thereby, since welding can be performed in a state where the extension part 201b is stably adhered, welding can be performed in a state where the extension parts 201b are arranged side by side in the vertical direction.

[0099] In a conventional secondary battery including a resin-metal composite substrate, when welding the plain part of the electrode, there is a problem that it hits only one surface in the metal film. In order to solve this, since it is necessary to go through a current-carrying process for passing current through the metal film, the manufacturing process may increase.

[0100] However, returning to FIG. 2, each of the plurality of electrode plates 210 and 220 included in the electrode assembly 200 according to an embodiment of the present invention includes a bent part 201c. And when the bent parts 201c are connected to each other, the first conductive layer F1 and the second conductive layer F2 of any one current collector layer 201 are connected to each other, and not only the first electrode plates 210 are electrically connected to each other, but also the second electrode plates 220 can be electrically connected to each other.

[0101] As described above, the electrode assembly 200 according to an embodiment of the present invention does not need to perform an additional current-carrying process of folding the foil and inserting it one by one between the electrode plates as in the prior art. Therefore, not only can the manufacturing time be shortened, but also the manufacturing cost can be saved.

[0102] Although various embodiments of the present invention have been described above, the drawings and the detailed description of the invention referred to so far are merely exemplary of the present invention, which have been used merely for the purpose of explaining the present invention and are not used for limiting the meaning or the scope of the present invention described in the claims. Therefore, those having ordinary knowledge in the technical field should be able to understand that various modifications and equivalent other embodiments are possible from now on. Therefore, the true technical protection scope of the present invention should be determined by the technical idea of the appended claims.

Explanation of Reference Numerals

[0103] 100: Secondary battery 200: Electrode assembly 201: Current collector layer 201a: Current collector part 201b: Extension part 201c: Bent part 202: Electrode plate layer 210: First electrode plate 220: Second electrode plate 230: Separator 300: Case E: Base layer F1: First conductive layer F2: Second conductive layer

Claims

1. An electrode plate including a base layer, a current collecting layer including a first conductive layer and a second conductive layer respectively located on the upper and lower surfaces of the base layer, and a current collector layer located on at least one surface of the current collecting layer, wherein the current collecting layer includes a current collecting portion on at least one surface of which the current collector layer is located, an extension portion extending from the current collecting portion to the outside, and a bent portion connected to the extension portion and bent two or more times so that the first conductive layer contacts the second conductive layer.

2. The electrode plate according to claim 1, wherein the base layer includes polyethylene terephthalate (PET).

3. The base layer includes one or more selected from the group consisting of polyamide, polyimide, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polyethylene propylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride-based, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin, derivatives of the foregoing materials, cross-linked products of the foregoing materials, and copolymers of the foregoing materials. The electrode plate according to claim 1.

4. The electrode plate according to claim 1, wherein the base layer further includes an additive, and the additive includes one or more of a metal material and an inorganic non-metal material.

5. The electrode plate according to claim 1, wherein the first conductive layer and the second conductive layer include aluminum.

6. The electrode plate according to claim 1, wherein the first conductive layer and the second conductive layer include one or more of a metal material, a carbon-based conductive material, and a conductive polymer material.

7. The electrode plate according to claim 1, wherein the bent portion has a jelly roll shape.

8. An electrode assembly including a plurality of electrode plates and a separator, wherein the plurality of electrode plates are laminated with the separator interposed therebetween, wherein each of the plurality of electrode plates includes a base layer, and a current collecting layer including a first conductive layer and a second conductive layer respectively located on the upper and lower surfaces of the base layer, including a current collector layer disposed on a part of the current collector layer; The current collector layer is a current collector portion having the electrode plate layer located on at least one surface; an extension portion extending from the current collector portion to the outside; an electrode assembly including a bent portion that is connected to the extension portion and is bent two or more times so that the first conductive layer contacts the second conductive layer. **Claim 9** The current collector layers included in each of the plurality of electrode plates are such that the bent portions adjacent to each other are joined to each other in the vertical direction, according to the electrode assembly of claim 8. **Claim 10** The plurality of electrode plates include a first electrode plate and a second electrode plate, according to the electrode assembly of claim 8. **Claim 11** The base layer includes polyethylene terephthalate (PET: polyethylene terephthalate), according to the electrode assembly of claim 8. **Claim 12** The base layer includes one or more selected from polyamide, polyimide, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polyethylene propylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin, derivatives of the foregoing materials, cross-linked bodies of the foregoing materials, and copolymers of the foregoing materials, according to the electrode assembly of claim 8. **Claim 13** The base layer further includes an additive, and the additive includes one or more of a metal material and an inorganic non-metal material, according to the electrode assembly of claim 8. **Claim 14** The first conductive layer and the second conductive layer include aluminum, according to the electrode assembly of claim 8. **Claim 15** The first conductive layer and the second conductive layer include one or more of a metal material, a carbon-based conductive material, and a conductive polymer material, according to the electrode assembly of claim 8. **Claim 16** The bent portion has a jelly roll shape, according to the electrode assembly of claim 8. **Claim 17** an electrode assembly, and a case for housing the electrode assembly. The electrode assembly is a secondary battery, which is the electrode assembly according to any one of claims 8 to 16.

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