Electrode assembly, secondary battery comprising same, and method for manufacturing secondary battery

Abstract

The present disclosure relates to a secondary battery and a method for manufacturing a secondary battery. An electrode assembly according to one embodiment of the present disclosure for achieving the technical objective comprises: a first electrode; a second electrode; and a separator disposed between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode includes: a polymer layer; a first metal layer disposed on a first surface of the polymer layer; a second metal layer disposed on a second surface opposite to the first surface; and a multilayer substrate including an active material layer applied to the first metal layer and the second metal layer, wherein the multilayer substrate may include a first portion where the polymer layer is filled between the first metal layer and the second metal layer, and a second portion where the polymer layer is not filled.

Description

Electrode assembly, secondary battery including same, and method for manufacturing secondary battery

[0001] The present disclosure relates to an electrode assembly, a secondary battery including the same, and a method for manufacturing the secondary battery.

[0002] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for motor drives and power storage in hybrid and electric vehicles. These secondary batteries include an electrode assembly comprising a positive and negative electrode, a case housing the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] Among the various types of secondary batteries, in the case of a cylindrical type, the negative electrode and the positive electrode are wound with a separator interposed between them and are accommodated in a case, and the open end of the case can be sealed with a cap assembly. In the wound state, the uncoated portion or electrode tab of one end of the negative or positive electrode can be bent and connected by welding to the electrode terminal of the cap assembly or to one side of the case.

[0004] Meanwhile, to increase the energy density of secondary batteries and reduce manufacturing costs, attempts are being made to replace the metal substrates of the cathode or anode with multilayer substrates in which metal films are deposited or bonded to both sides of the polymer layer. However, high production efficiency is difficult to achieve due to the difficulties in performing bending or compaction processes for electrodes containing multilayer substrates, or in performing welding processes with cap assemblies or electrode terminals.

[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] The problem to be solved by the present disclosure is to provide an electrode assembly for solving the above-mentioned problems, a secondary battery including the same, and a method for manufacturing the secondary battery.

[0007] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0008] An electrode assembly according to one embodiment of the present disclosure for solving a technical problem includes a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode includes a multilayer substrate including a polymer layer, a first metal layer disposed on a first side of the polymer layer, a second metal layer disposed on a second side opposite to the first side, and an active material layer applied to the first metal layer and the second metal layer, wherein the multilayer substrate may include a first portion where the polymer layer is filled between the first metal layer and the second metal layer, and a second portion where the polymer layer is not filled.

[0009] According to one embodiment, the first electrode, the second electrode, and the separator are formed by winding around the core portion, and the multilayer substrate can be bent in a direction intersecting the axial direction of the core portion in the second portion.

[0010] In one embodiment, the second portion may extend from the first portion and be positioned at an end of the multilayer substrate.

[0011] According to one embodiment, the multilayer substrate may include a plurality of segments formed by notching at least a portion of the second portion.

[0012] In one embodiment, the multilayer substrate may further include a third portion, the second portion being connected to a side opposite to the side to which the first portion is connected, and having a polymer layer filled between two metal layers.

[0013] In one embodiment, the third portion may be welded to the second portion.

[0014] According to one embodiment, the first electrode, the second electrode, and the separator are formed by winding around the core portion, and the multilayer substrate can be bent in a direction intersecting the axial direction of the core portion in the second portion.

[0015] According to one embodiment, the multilayer substrate may further include a current pass member arranged between a plurality of adjacent third portions while the first electrode, the second electrode, and the separator are wound around the core.

[0016] According to one embodiment of the present disclosure for solving the technical problem, a secondary battery includes an electrode assembly including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, a case for accommodating the electrode assembly inserted through an opening formed in one side thereof, and a cap assembly for sealing the opening of the case, wherein at least one of the first electrode and the second electrode of the electrode assembly includes a multilayer substrate including a polymer layer, a first metal layer disposed on a first side of the polymer layer, a second metal layer disposed on a second side opposite to the first side, and an active material layer applied to the first metal layer and the second metal layer, and the multilayer substrate may include a first portion in which the polymer layer is filled between the first metal layer and the second metal layer, and a second portion in which the polymer layer is not filled.

[0017] According to one embodiment, the electrode assembly is formed by winding a first electrode, a second electrode, and a separator around a core portion, and the multilayer substrate can be bent in a direction intersecting the axial direction of the core portion in the second portion.

[0018] According to one embodiment, the multilayer substrate may include a plurality of segments formed by notching at least a portion of the second portion.

[0019] In one embodiment, the multilayer substrate may further include a third portion, the second portion being connected to a side opposite to the side to which the first portion is connected, and the third portion having a polymer layer filled between two metal layers.

[0020] According to one embodiment, the electrode assembly is formed by winding a first electrode, a second electrode, and a separator around a core portion, and the multilayer substrate can be bent in a direction intersecting the axial direction of the core portion in the second portion.

[0021] According to one embodiment, the multilayer substrate may further include a current pass member arranged between a plurality of adjacent third portions while the first electrode, the second electrode, and the separator are wound around the core.

[0022] A method for manufacturing a secondary battery according to one embodiment of the present disclosure for solving a technical problem may include the steps of manufacturing a multilayer substrate including a first portion in which a polymer layer is filled between two metal layers and a second portion in which the polymer layer is not filled; the steps of winding the multilayer substrate; the steps of bending the second portion of the multilayer substrate; and the steps of performing a compaction process on the bent second portion of the multilayer substrate; and the steps of welding a current collector plate to the second portion of the multilayer substrate.

[0023] According to one embodiment, the method may further include the step of notching at least a portion of the second portion of the multilayer substrate to create a plurality of segments.

[0024] In one embodiment, the step of bending the second portion of the multilayer substrate may include the step of bending the second portion toward the core of the rolled multilayer substrate.

[0025] According to one embodiment, the second portion of the multilayer substrate may further include a step of welding a third portion filled with a polymer layer filled between two metal layers.

[0026] According to one embodiment, the method may further include a step of arranging a current pass member between a plurality of adjacent third portions of the multilayer substrate while the multilayer substrate is wound.

[0027] According to one embodiment, the method may further include the step of notching at least a portion of a third portion of the multilayer substrate to create a plurality of segments.

[0028] According to some embodiments of the present invention, when a multilayer substrate is used as an electrode of a secondary battery, additional bonding of a general substrate is not required to form a section for bending the multilayer substrate, so simplification in the manufacturing process can be expected.

[0029] According to some embodiments of the present invention, improved welding quality can be expected during the welding process with an electrode terminal or a current collector by easy bending of a cathode and an anode including a multilayer substrate.

[0030] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0032] FIG. 1 is a perspective view of a cylindrical secondary battery according to one embodiment of the present disclosure.

[0033] FIG. 2 is a cross-sectional view taken along line A-A' of a cylindrical secondary battery according to one embodiment of the present disclosure.

[0034] FIG. 3 is a B-B' cross-sectional view of a cylindrical secondary battery according to one embodiment of the present disclosure.

[0035] FIG. 4 is a drawing showing a multilayer substrate according to the first embodiment of the present disclosure. FIG. 4(a) is a drawing showing a cross-section of the multilayer substrate before bending. FIG. 4(b) is a drawing showing a cross-section of the multilayer substrate after bending.

[0036] Figure 5 is a development diagram of a multilayer substrate according to the first embodiment of the present disclosure.

[0037] FIG. 6 is a drawing showing a multilayer substrate according to a second embodiment of the present disclosure.

[0038] FIG. 7(a) and FIG. 7(b) are drawings showing an example of a manufacturing process of a multilayer substrate according to the second embodiment of the present disclosure.

[0039] FIG. 8 is a drawing showing another example of a manufacturing process of a multilayer substrate according to the second embodiment of the present disclosure.

[0040] FIG. 9 is a drawing showing a bent state of a second part of a multilayer substrate according to a second embodiment of the present disclosure.

[0041] FIG. 10 is a drawing showing a current pass member interposed between multilayer substrates according to a second embodiment of the present disclosure.

[0042] Fig. 11 is a development diagram of a multilayer substrate according to a second embodiment of the present disclosure.

[0043] Figure 12 illustrates a current pass member connected to a multilayer substrate according to a third embodiment of the present disclosure. Figure 12(a) is a drawing illustrating a current pass member being placed in contact with a side surface of the multilayer substrate. Figure 12(b) is a drawing illustrating a bend portion being formed in the current pass member and being bent.

[0044] Fig. 13 is a development diagram of a multilayer substrate according to a third embodiment of the present disclosure.

[0045] Figure 14 is a flowchart showing a manufacturing process of an electrode assembly according to one embodiment of the present disclosure.

[0046] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0047] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0048] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0049] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0050] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0051] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0052] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0053] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0054] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0055] The terminology used herein is for the purpose of describing embodiments of the invention and is not intended to limit the invention.

[0056] FIG. 1 is a perspective view of a cylindrical secondary battery (100) according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line A-A' of a cylindrical secondary battery (100) according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional view taken along line B-B' of a cylindrical secondary battery (100) according to an embodiment of the present disclosure. Referring to FIGS. 1 and 2, the secondary battery (100) accommodates an electrode assembly (170) formed in a wound form inside a cylindrical case (180), and a vent cap plate (142) can seal an opening or beading portion (189) of the case (180). The internal configuration of the secondary battery (100) is described with reference to Fig. 2, which shows a cross-sectional view of the secondary battery (100) taken along line A-A' on the XZ plane, and Fig. 3, which shows a cross-sectional view of the secondary battery (100) taken along line B-B' on the XY plane.

[0057] Referring to FIG. 2, the electrode assembly (110) may include a first electrode (171a), a second electrode (172a), and a separator (173) disposed between the first electrode (171a) and the second electrode (172a). A secondary battery (100) according to one embodiment of the present disclosure includes an electrode assembly (110) that functions as a charge and discharge electrode, a case (180) housing the electrode assembly (110), a current collector (150, 190) connected to the electrode assembly (170), an electrode terminal (141), a vent cap plate (142), and a sealing member (160). In this example, the vent cap plate (142) is depicted as being disposed on the upper side of the secondary battery (100), and the electrode terminal (141) is disposed on the lower side of the secondary battery (100), but is not limited thereto. Depending on the usage environment or requirements of the secondary battery (100), the vent cap plate (142) and electrode terminal (141) may be changed to be placed at the bottom and top of the secondary battery, respectively.

[0058] An electrode assembly (170) is formed by winding a first electrode (171a, 171b), a separator (173), and a second electrode (172a, 172b) into a cylindrical jelly roll state with an empty core. The first electrode (171a, 171b) and the second electrode (172a, 172b) each include an active material layer in an area where an active material is applied to both sides of a substrate formed of a thin metal plate, and a non-conductive area (171b, 172b) in an area where the substrate is exposed because the active material is not applied.

[0059] The first electrode (171a, 171b) may be an electrode corresponding to a positive or negative electrode in a secondary battery. The second electrode (172a, 172b) may be an electrode corresponding to a pole opposite to the first electrode (171a, 171b). For example, if the first electrode (171a, 171b) is a positive electrode, the second electrode (172a, 172b) may be a negative electrode. Conversely, if the first electrode (171a, 171b) is a negative electrode, the second electrode (172a, 172b) may be a positive electrode.

[0060] As an example, the first electrode (171a, 171b) may be formed as a positive electrode by coating a positive electrode active material on an aluminum (Al) substrate, and the second electrode (172a, 172b) may be formed as a negative electrode by coating a negative electrode active material on a copper (Cu) substrate. The uncoated portion (171b) of the first electrode (171a, 171b) and the uncoated portion (172b) of the second electrode (172a, 172b) are respectively provided at opposite ends in the winding axis direction of the electrode assembly (110), but electrode terminals (141) and cases (180) having different polarities in the same direction are provided together. A vent cap plate (142) is positioned on the opposite side of the electrode terminal (141).

[0061] The case (180) is formed in a cylindrical shape to house the electrode assembly (110), and the electrode terminal (141) and the vent cap plate (142) are provided at each of the axial ends of the case (180) so as to face each other.

[0062] The electrode terminal (141) is connected to the first electrode (171a, 171b) through the first collector plate (190) via the rivet portion (143), and the case (180) is connected to the second electrode (172a, 172b) through the second collector plate (150). At this time, the vent cap plate (142) is electrically separated from the second collector plate (150) and the case (120) and has no polarity.

[0063] An electrode terminal (141) connected to a first electrode (171a, 171b) of an electrode assembly (110) inserted into a case (120) from the outside is installed on one side of the case. The case (180) has a partially open through hole (181) on one side. At this time, the first current collector (190) is electrically connected to the non-coated portion (171b) of the first electrode through a rivet portion (143) and is electrically and mechanically connected to the electrode terminal (141). The current collector is electrically connected to the electrode terminal (141) in a structure that contacts most of the non-coated portion (171b) of the first electrode (171a, 171b) to reduce resistance. The rivet portion (143) included in the electrode terminal (141) can be installed in an electrically insulated state from the case (180) while forming a gasket (183) in the through hole (181) to form a sealing structure against the electrolyte.

[0064] Here, the gasket (163) may be made of a polymer including ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or a combination thereof.

[0065] As another example, the gasket (183) may be made of a ceramic material including epoxy resin, alumina (Al2O3), zirconia (ZrO2), aramid fiber, Nomex, or a combination thereof. However, the material of the gasket (183) is not limited to the materials listed above, and may include various materials with excellent plasticity and insulation properties depending on the selection.

[0066] In one embodiment, the first collector plate (190) may include a metal plate (191) including at least one bridge (192). For example, the first collector plate (190) may be formed of a conductive metal, specifically, a conductive metal such as nickel, aluminum, copper, silver, zinc, tin, stainless steel (e.g., SUS), nickel-plated steel, or a combination (alloy) thereof. In addition, the metal plate (191) and the bridge (192) constituting the first collector plate (190) may be made of the same material to form an integral body.

[0067] Here, the bridge (192) of the first collector plate (190) may be configured to be ruptured when a current exceeding a set value flows. For example, the bridge (192) normally operates as a part of a circuit through which current flows, but when an excessive amount of current flows, it may function as a fuse that melts due to the generated heat and blocks the circuit.

[0068] An insulating tape (145) may be attached to one side of the first collector plate (190). The insulating tape (145) may be interposed between the first collector plate (190) and the case (120) or between the non-conductive portion (171b) of the first electrode and the case (180) to electrically insulate each component. In one embodiment, the central portion of the insulating tape (145) may include a perforation (146) corresponding to the shape of the rivet portion (143) so that the rivet portion (143) may come into contact with the first collector plate (190). In addition, the insulating tape (145) may include a side wall (147) so as to surround a portion of the electrode assembly (110).

[0069] Additionally, the case (180) has a fully open opening (182) to allow the electrode assembly (110) to be inserted into the other side. The vent cap plate (142) seals the opening (182) after the electrode assembly (110) is inserted into the case (120) and is electrically isolated from the case (120).

[0070] At this time, the second collector plate (150) is electrically connected to the non-conductive portion (112b) of the second electrode and is electrically connected to the case (120). The second collector plate (150) is connected to the case (120) in a structure that reduces resistance by contacting most of the non-conductive portion (112b) of the second electrode.

[0071] The second collector plate (150) includes a bottom portion (151) welded to the non-conductive portion (112b) of the second electrode, and wing portions (152) formed adjacent to the bottom portion (151) and welded to the beading portion (129). The second collector plate (150) is formed by cutting and bending a circular plate, and each of the bottom portions (151) and wing portions (152) is provided in multiple numbers and arranged alternately along the circumferential direction. In one embodiment, the wing portions (152) can be repeatedly formed by bending the axial direction (upward) and radial direction (outer) of the electrode assembly (110).

[0072] In one embodiment, when the non-coated portion (172b) of the second electrode and the bottom portion (151) of the second collector plate (150) are welded, the bottom portion (151) can form a welding line in the diameter direction of the second collector plate (150). Accordingly, the bottom portion (151) can be evenly connected along the circumferential direction in the area of ​​the non-coated portion (112b) of the second electrode, and the wing portion (152) can be evenly connected along the circumferential direction in the area of ​​the beaded portion (189). This can enable a uniform current flow along the circumferential direction in the entire area of ​​the beaded portion (189) of the case (180) from the non-coated portion (172b) of the second electrode.

[0073] In addition, since the second collector plate (150) has a hole (153) in the center, it can absorb and alleviate deformation caused by welding of the bottom portion (151) and the non-conductive portion (172b) of the second electrode, as well as vibration and shock that may be transmitted between the wing portion (152) and the bottom portion (151). The hole (153) can have a size that can absorb vibration and shock without increasing the current resistance between the wing portion (152) and the bottom portion (151).

[0074] The vent cap plate (142) is electrically isolated from the second collector plate (150) and is installed in the opening (182) of the case (180) through a crimping process. Alternatively, the vent cap plate (142) is installed in the opening (182) of the case (180) through a welding process. Due to the connection of the second collector plate (150), the case (180) can be used as a negative terminal. In this case, the second collector plate (150) becomes a negative collector plate.

[0075] The vent cap plate (142) may form a notch (144) on its inner surface. The notch (144) may be cut open to release internal pressure of the secondary battery to the outside when an abnormal event occurs in the secondary battery, thereby preventing a secondary explosion. Specifically, the notch (144) intensively receives internal pressure in the event of an abnormal event, thereby enabling easy cutting. The notch (144) may be formed over the entire circumferential area of ​​the vent plate (142), or may be formed in multiple pieces spaced apart at set intervals.

[0076] The sealing member (160) is interposed between the second collector plate (150) and the vent cap plate (142) and between the second collector plate (130) and the case (180) to seal the case by means of a beading portion (129) or a crimping process. In addition, the sealing member (160) can form a sealing structure with respect to the electrolyte between the second collector plate (150) and the opening (182) of the case (180).

[0077] For example, the sealing member (160) may include a polymer material or ceramic such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE or Teflon), polyethylene (PE), epoxy resin, silicone, polyvinylidene fluoride (PVDF), polypropylene (PP), polyacrylonitrile (PAN), or polyethylene oxide (PEO), but is not limited thereto, and may correspond to any one of the appropriate compounds used as an insulating material in the art.

[0078] Referring to FIG. 3, the uncoated portion (171b) of the first electrode (171a) of the wound electrode assembly (170) can be bent toward the core portion. For example, as illustrated, a plurality of segments formed in the first uncoated portion (171b) of the first electrode (171a) can be bent by a compaction process. Additionally, the bent first uncoated portion (172b) can be connected to the current collector (150) by welding.

[0079] Additionally, at least one of the first electrode (171a) and the second electrode (172a) may include a multilayer substrate. Here, the multilayer substrate may include a first portion having a polymer layer disposed between two metal layers, a second portion connected to the first portion and not having a polymer layer disposed between the two metal layers, and / or a third portion connected to the second portion and having a polymer layer disposed between the two metal layers. The multilayer substrate may be bent at the second portion, and the bent second portion and / or third portion may be connected to the collector plate (150) by welding. Additionally, a current pass member may be connected to the second portion and / or the third portion of the multilayer substrate. In this case, the current pass member may be connected to the collector plate (150) by welding.

[0080] In this way, when at least one of the electrodes (171a, 172a) of the secondary battery (100) is implemented using a multilayer substrate, simplification of the manufacturing process can be expected since additional bonding of a general substrate is not required to form a section for bending the multilayer substrate. In addition, improved welding quality can be expected during the welding process with the electrode terminal or current collector (150) of the secondary battery (100) due to easy bending of the negative electrode and positive electrode including the multilayer substrate.

[0081] FIG. 4 is a drawing illustrating a multilayer substrate according to a first embodiment of the present disclosure. FIG. 4(a) is a drawing illustrating a cross-section of the multilayer substrate before bending. FIG. 4(b) is a drawing illustrating a cross-section of the multilayer substrate after bending. The multilayer substrate illustrated in FIG. 4 may be included in at least one of the first electrode (171a) and the second electrode (172a) described with reference to FIGS. 1 to 3.

[0082] Referring to FIG. 4, the multilayer substrate may include a polymer layer (112), a first metal layer (111) disposed on a first surface of the polymer layer (112), a second metal layer (111) disposed on a second surface opposite to the first surface, and an active material layer (not shown) applied to the first metal layer (111) and the second metal layer (111). Here, the multilayer substrate may include a first portion (S1) in which the polymer layer (112) is filled between the first metal layer (111) and the second metal layer (111), and a second portion (S2) connected to the first portion (S1) and in which the polymer layer (112) is not filled. Here, the second portion (S2) may extend from the first portion (S1) and be positioned at an end of the multilayer substrate.

[0083] Before the compaction process is performed, the second portion (S2) may extend in the longitudinal direction of the first portion (S1), as illustrated in FIG. 5(a). When bending occurs through the compaction process, a bend portion (F) may be formed at a point in the second portion (S2). The bending direction of the second portion (S2) may be a direction toward the core portion when the first electrode (171a) and / or the second electrode (172a) is wound. Since the polymer layer (112) has a predetermined rigidity, the first portion (S1) may not be easily bent during the compaction process. Therefore, it may be more efficient to bend the second portion (S2) or the unfilled portion (113) that is not filled with the polymer layer during the compaction process. For example, as illustrated in FIG. 5(b), a folded portion (F) may be formed in an area of ​​the second portion (S2) adjacent to the point where the first portion (S1) and the second portion (S2) contact each other.

[0084] FIG. 5 is a development diagram of a multilayer substrate according to a first embodiment of the present disclosure. Referring to FIG. 5, the multilayer substrate may include a plurality of segmented portions (116) formed by notching at least a portion of a second portion (S2). The segmented portions (116) may be a portion of a non-filled portion (117). The segmented portions (116) may be formed by performing a notching process on the second portion (S2) including the unfilled portion (113). The notching may be performed by laser irradiation. The segmented portions (116) may be bent toward the core portion while the electrode assembly (170) is wound. During the bending process, overlapping may occur between adjacent segmented portions (116).

[0085] FIG. 6 is a drawing illustrating a multilayer substrate according to a second embodiment of the present disclosure. The multilayer substrate illustrated in FIG. 6 may be included in at least one of the first electrode (171a) and the second electrode (172a) described with reference to FIGS. 1 to 3.

[0086] Referring to FIG. 6, the multilayer substrate may include a polymer layer (122-1), a first metal layer (121) disposed on a first surface of the polymer layer (122-1), a second metal layer (121) disposed on a second surface opposite to the first surface, and an active material layer (not shown) applied to the first metal layer (121) and the second metal layer (121). Here, the multilayer substrate may include a first portion (S1) in which the polymer layer (122-1) is filled between the first metal layer (121) and the second metal layer (121), and a second portion (S2) connected to the first portion (S1) and in which the polymer layer (122) is not filled.

[0087] In addition, the multilayer substrate may further include a third portion (S3) connected to a side opposite to the side to which the first portion (S1) is connected in the second portion (S2), and in which a polymer layer (122-2) is filled between two metal layers (121). That is, the polymer layers (122-1, 122-2) may be formed on both sides of the second section, which is the unfilled portion (123). The first portion (S1), the second portion (S2), and the third portion (S3) may be unfilled portions, and at least the second portion (S2) and the third portion (S3) may be unfilled portions.

[0088] FIG. 7(a) and FIG. 7(b) are diagrams showing an example of a manufacturing process of a multilayer substrate according to a second embodiment of the present disclosure. Referring to FIG. 7, a third portion (S3) can be joined to a second portion (S2) by welding. The welding can be performed so that each of one end of the first metal layer (121-1) and the second metal layer (121-1) of the second portion (S2) and each of one end of the first metal layer (121-2) and the second metal layer (121-2) of the third section are joined to each other. Through this, a welded portion (W) can be formed at the connection portion between the second portion (S2) and the third portion (S3).

[0089] FIG. 8 is a diagram illustrating another example of a manufacturing process of a multilayer substrate according to a second embodiment of the present disclosure. As illustrated in FIG. 8, a polymer layer (122) may be prepared. Metal particles (P) may be deposited on both surfaces of the prepared polymer layer (122). The deposition of the metal particles (P) may proceed until a metal layer (121) having a predetermined thickness is formed. Once the metal layer (121) is formed on both surfaces of the polymer layer (122) by deposition, an unfilled portion (123) for bending may be provided.

[0090] The unfilled portion (123) can be formed by irradiating a laser onto a portion of the polymer layer (122). For example, a portion of the polymer layer (122) can be etched and removed with a laser to form an unfilled portion (123) in which PET is not filled. Accordingly, the unfilled portion (123) can be formed between the polymer layers (122-1, 122-2). Here, the thickness of the metal layer (121) can be several micrometers. The portion where the first polymer layer (122-1) is formed can correspond to a first portion (S1), the portion where the second polymer layer (122-2) is formed can correspond to a third portion, and the portion where the unfilled portion (123) is formed can correspond to a second portion (S2).

[0091] Meanwhile, an active material layer (not shown) may be formed by applying an active material to a portion of the surface opposite to the surface in contact with the polymer layer (122) in the metal layer (121).

[0092] FIG. 9 is a drawing showing a state in which a second portion (S2) of a multilayer substrate according to a second embodiment of the present disclosure is folded. Referring to FIG. 9, the multilayer substrate can be folded at the second portion (S2). For example, as described above, in a state in which the first electrode (171a), the second electrode (172a), and the separator (173) are wound around the core, the second portion (S2) of the multilayer substrate can be folded in a direction intersecting the axial direction of the core (for example, in the direction toward the core).

[0093] The second portion (S2) of the multilayer substrate can be bent to form a bent portion (F). In a state where the second portion (S2) is bent, the third section can extend in the bending direction. The first portion (S1) and the third portion (S3) filled with polymer layers (122-1, 122-2) have a predetermined strength, and thus may not be easily bent. In contrast, the second portion (S2) not filled with a polymer layer may be easily bent. Therefore, the compaction process can be performed on the second portion (S2) of the multilayer substrate.

[0094] FIG. 10 is a drawing showing a current pass member (10) interposed between multilayer substrates according to a second embodiment of the present disclosure. Referring to FIG. 10, in an electrode assembly in a wound state, a gap may be formed between folded multilayer substrates. Accordingly, when the non-coated portion or the third portion (S3) of the multilayer substrate is folded, if the length of the third portion (S3) is not sufficiently long, contact between adjacent multilayer substrates may not be formed. Therefore, a current pass member (10) may be interposed between the multilayer substrates so that contact between the multilayer substrates can be more effectively formed and electrically connected. Specifically, the current pass member (10) may be positioned on the side of the third portion (S3) of the multilayer substrate.

[0095] For example, in a state where the first electrode (171a), the second electrode (172a), and the separator (173) of the electrode assembly are wound around the core, a current pass member (10) arranged between a plurality of adjacent third parts (S3) of the multilayer substrate may be further included.

[0096] Fig. 11 is a development diagram of a multilayer substrate according to a second embodiment of the present disclosure. Referring to Fig. 11, the multilayer substrate may include a plurality of segments (126) formed by notching the entire third portion (S3) and at least a portion of the second portion (S2). The segments (126) may be a portion of the unfilled portion (127), and more specifically, may be formed by performing notching on the second portion (S2) and the third portion (S3), where an unfilled portion (123) in which a polymer layer is not filled is formed between two metal layers. The notching may be performed by laser irradiation. The segments (126) may be bent toward the winding portion when the multilayer substrate is in a wound state. During the bending process, overlapping may occur between adjacent segments (126).

[0097] FIG. 12 illustrates a current pass member (10) being connected to a multilayer substrate according to a third embodiment of the present disclosure. FIG. 12(a) is a drawing illustrating that the current pass member (10) is arranged in contact with a side surface of the multilayer substrate. FIG. 12(b) is a drawing illustrating that a bending portion (F) is formed in the current pass member (10) and is bent. Referring to FIG. 12, the current pass member (10) may be bonded to one side surface of a multilayer substrate including a metal layer (131) arranged on both surfaces of a polymer layer (132). Such a configuration may include a first portion (S1) including the multilayer substrate, and a second portion (S2) in which the current pass member (10) attached to the multilayer substrate protrudes from one end of the multilayer substrate. The current pass member (10) may be bent by performing a compaction process. Accordingly, a bending portion (F) can be formed in the portion corresponding to the second portion (S2) of the current pass member (10).

[0098] Fig. 13 is a development diagram of a multilayer substrate according to a third embodiment of the present disclosure. Referring to Fig. 13, the multilayer substrate may include a plurality of segmented portions (136) formed by notching at least a portion of a second portion (S2) including a current pass member (10). The segmented portions (136) may be a portion of a non-coated portion (137), and more specifically, may be formed by notching the second portion (S2) including at least a portion of the current pass member (10) where the multilayer substrate is not overlapped. The notching may be performed by laser irradiation. The segmented portions (136) may be bent toward the winding portion when the multilayer substrate is in a wound state. During the bending process, overlapping may occur between adjacent segmented portions (136).

[0099] Figure 14 is a flowchart showing a manufacturing process of an electrode assembly according to one embodiment of the present disclosure.

[0100] A method for manufacturing a secondary battery (100) according to one embodiment of the present disclosure may include a step (S10) of manufacturing a multilayer substrate including a first portion in which a polymer layer is filled between two metal layers and a second portion in which the polymer layer is not filled, a step (S20) of winding the multilayer substrate, a step (S30) of bending the second portion of the multilayer substrate, a step (S40) of performing a compaction process on the bent second portion of the multilayer substrate, and a step (S50) of welding a current collector to the second portion of the multilayer substrate.

[0101] According to one embodiment, the method of manufacturing a secondary battery may further include the step of notching at least a portion of a second portion of the multilayer substrate to create a plurality of segments.

[0102] In one embodiment, the step of bending the second portion of the multilayer substrate may include a step of bending the second portion toward the core of the rolled multilayer substrate. This may correspond to a step of preliminarily determining the bending direction of the multilayer substrate prior to performing the compaction process.

[0103] In one embodiment, a method for manufacturing a secondary battery may further include a step of welding a third portion, wherein the third portion is filled with a polymer layer between two metal layers, to a second portion of the multilayer substrate. Furthermore, the method may further include a step of arranging a current-passing member between a plurality of adjacent third portions of the multilayer substrate while the multilayer substrate is wound. Additionally, the method may further include a step of notching at least a portion of the third portion of the multilayer substrate to create a plurality of segments.

[0104] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. First electrode; a second electrode; and A separator is included between the first electrode and the second electrode, At least one of the first electrode and the second electrode, polymer layer; A first metal layer disposed on the first surface of the polymer layer; A second metal layer disposed on a second surface opposite to the first surface; and A multilayer substrate comprising an active material layer applied to the first metal layer and the second metal layer, An electrode assembly, wherein the multilayer substrate includes a first portion in which the polymer layer is filled between the first metal layer and the second metal layer, and a second portion in which the polymer layer is not filled.

2. In paragraph 1, The first electrode, the second electrode, and the separator are formed by winding around the core, An electrode assembly in which the multilayer substrate is bent in a direction intersecting the axial direction of the core portion in the second portion.

3. In paragraph 1, An electrode assembly, wherein the second portion extends from the first portion and is positioned at an end of the multilayer substrate.

4. In paragraph 1, An electrode assembly, wherein the multilayer substrate includes a plurality of segments formed by notching at least a portion of the second portion.

5. In paragraph 1, An electrode assembly wherein the multilayer substrate further includes a third portion, in which the second portion is connected to a side opposite to the side to which the first portion is connected, and a polymer layer is filled between two metal layers.

6. In paragraph 5, An electrode assembly wherein the third part is welded to the second part.

7. In paragraph 6, The first electrode, the second electrode, and the separator are formed by winding around the core, An electrode assembly in which the multilayer substrate is bent in a direction intersecting the axial direction of the core portion in the second portion.

8. In paragraph 7, An electrode assembly further comprising a current pass member arranged between a plurality of adjacent third portions of the multilayer substrate, while the first electrode, the second electrode, and the separator are wound around the core portion.

9. An electrode assembly comprising a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; A case for accommodating the electrode assembly inserted through an opening formed on one side; and A cap assembly is included that seals the opening of the case, At least one of the first electrode and the second electrode of the electrode assembly, polymer layer; A first metal layer disposed on the first surface of the polymer layer; A second metal layer disposed on a second surface opposite to the first surface; and A multilayer substrate comprising an active material layer applied to the first metal layer and the second metal layer, A secondary battery, wherein the multilayer substrate includes a first portion in which the polymer layer is filled between the first metal layer and the second metal layer, and a second portion in which the polymer layer is not filled.

10. In paragraph 9, The above electrode assembly is formed by winding the first electrode, the second electrode, and the separator around the core, A secondary battery, wherein the multilayer substrate is bent in a direction intersecting the axial direction of the core portion in the second portion.

11. In paragraph 9, A secondary battery, wherein the multilayer substrate includes a plurality of segments formed by notching at least a portion of the second portion.

12. In paragraph 9, A secondary battery, wherein the multilayer substrate further includes a third portion, in which the second portion is connected to a side opposite to the side to which the first portion is connected, and a polymer layer is filled between two metal layers.

13. In paragraph 12, The above electrode assembly is formed by winding the first electrode, the second electrode, and the separator around the core, A secondary battery, wherein the multilayer substrate is bent in a direction intersecting the axial direction of the core portion in the second portion.

14. In paragraph 13, A secondary battery further comprising a current pass member arranged between a plurality of adjacent third portions of the multilayer substrate, while the first electrode, the second electrode, and the separator are wound around the core portion. A step of manufacturing a multilayer substrate including a first portion in which a polymer layer is filled between 15.2 metal layers and a second portion in which the polymer layer is not filled; A step of winding the above multilayer substrate; A step of bending the second part of the multilayer substrate; and A step of performing a compaction process on the folded second portion of the multilayer substrate; and A method for manufacturing a secondary battery, comprising: a step of welding a current collector plate to the second portion of the multilayer substrate.

16. In paragraph 15, A method for manufacturing a secondary battery, further comprising the step of notching at least a portion of the second portion of the multilayer substrate to create a plurality of segments.

17. In paragraph 15, The step of bending the second part of the multilayer substrate is: A method for manufacturing a secondary battery, comprising a step of bending the second portion toward the core of the rolled multilayer substrate.

18. In paragraph 15, A method for manufacturing a secondary battery, further comprising the step of welding a third portion filled with a polymer layer filled between two metal layers to the second portion of the multilayer substrate.

19. In paragraph 18, A method for manufacturing a secondary battery, further comprising the step of arranging a current pass member between a plurality of adjacent third portions of the multilayer substrate while the multilayer substrate is wound.

20. In paragraph 18, A method for manufacturing a secondary battery, further comprising the step of notching at least a portion of the third portion of the multilayer substrate to create a plurality of segments.

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