Electrode and secondary battery comprising same

Abstract

The present disclosure provides an electrode and a secondary battery comprising same. The electrode may comprise: an insulation film layer made of an insulation material; a first metal layer coated on one surface of the insulation film layer; a second metal layer coated on the other surface of the insulation film layer; a first substrate connected to the first metal layer; and a second substrate connected to the second metal layer and the first substrate so as to electrically connect the first metal layer, the second metal layer, and the first substrate.

Description

Electrode and secondary battery including the same

[0001] The present disclosure relates to an electrode and a secondary battery comprising the same.

[0002]

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and power storage batteries in hybrid and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case housing the assembly, and electrode terminals connected to the electrode assembly.

[0004] Generally, electrode assemblies frequently use copper or aluminum as electrode materials. However, in the case of aluminum, there is a problem where it comes into contact with the negative electrode active material upon a short circuit, leading to ignition.

[0005] To solve this problem, a method of manufacturing electrodes by coating a metal on a polymer substrate such as PET (polyethylene terephthalate) has been proposed. However, there is a problem in that it is difficult to form a current path due to the PET substrate.

[0006] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0007]

[0008] The present disclosure provides an electrode for solving the above-mentioned problems and a secondary battery including the same.

[0009] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0010]

[0011] An electrode according to one embodiment of the present invention for solving the above technical problem may include: an insulating film layer made of an insulating material; a first metal layer coated on one side of the insulating film layer; a second metal layer coated on the other side of the insulating film layer; a first substrate connected to the first metal layer; and a second substrate connected to the second metal layer and the first substrate to electrically connect the first metal layer, the second metal layer, and the first substrate.

[0012] According to one embodiment of the present invention, the length of the second material protruding outward from the second metal layer in a direction parallel to the winding axis may be shorter than the length of the first material protruding outward from the first metal layer.

[0013] According to one embodiment of the present invention, one end of the second substrate may be connected to the second metal layer, and the other end may be connected to the first substrate.

[0014] According to one embodiment of the present invention, the second substrate can be connected to the first substrate after being bent toward the first substrate while one end is connected to the second metal layer.

[0015] According to one embodiment of the present invention, after the first substrate, the first metal layer, and one end of the second substrate and the second metal layer are simultaneously connected, the other end of the second substrate can be connected to the first substrate.

[0016] According to one embodiment of the present invention, one end of the first substrate and the second substrate may be ultrasonically welded to have a connection width of 1 to 2 mm.

[0017] According to one embodiment of the present invention, the other ends of the first substrate and the second substrate may be ultrasonically welded to have a connection width of 1 to 2 mm.

[0018] According to one embodiment of the present invention, a first substrate may be connected to a first metal layer, and one end of a second substrate may be connected to a second metal layer, and at the same time, the first substrate may be connected to the other end of the second substrate.

[0019] According to one embodiment of the present invention, the first substrate and the second substrate may be ultrasonically welded to have a connection width of 2 to 4 mm.

[0020] According to one embodiment of the present invention, the second substrate may have a length in a direction parallel to the winding axis of 30 to 60% of the length of the first substrate.

[0021] According to one embodiment of the present invention, the first substrate may include a plurality of foldable tabs formed in an area where the second substrate is not connected.

[0022] According to one embodiment of the present invention, a plurality of tabs may be bent at a point 70 to 80% in a direction parallel to the winding axis at the outer end.

[0023] According to one embodiment of the present invention, a notching portion may be included in which a first substrate or a first substrate and a second substrate are cut in a direction parallel to the winding direction at the winding tip.

[0024] According to one embodiment of the present invention, the length of the notching portion in a direction parallel to the winding direction may be 5 to 10% of the length of the insulating film layer.

[0025] A secondary battery according to an embodiment of the present invention for solving a technical problem comprises: an electrode assembly having a first electrode, a second electrode, and a separator wound thereon; a case having a bottom portion having one side open and a through hole formed on the other side, in which the electrode assembly is received and electrically connected to the second electrode; a vent cap plate fastened to the open side of the case; a rivet portion disposed through the through hole and electrically connected to the first electrode, and a gasket provided in the through hole to electrically insulate the case and the rivet portion, wherein at least one of the first electrode and the second electrode may comprise an insulating film layer made of an insulating material; a first metal layer coated on one side of the insulating film layer; a second metal layer coated on the other side of the insulating film layer; a first substrate connected to the first metal layer; and a second substrate connected to the second metal layer and the first substrate to electrically connect the first metal layer, the second metal layer, and the first substrate.

[0026] According to one embodiment of the present invention, the length of the second material protruding outward from the second metal layer in a direction parallel to the winding axis may be shorter than the length of the first material protruding outward from the first metal layer.

[0027] According to one embodiment of the present invention, one end of the second substrate may be connected to the second metal layer, and the other end may be connected to the first substrate.

[0028] According to one embodiment of the present invention, the first substrate may include a plurality of foldable tabs formed in an area where the second substrate is not connected.

[0029] According to one embodiment of the present invention, a plurality of tabs may be bent so that a second substrate is disposed on the inside.

[0030] According to one embodiment of the present invention, a plurality of tabs may be bent at a point 70 to 80% in a direction parallel to the winding axis at the outer end.

[0031]

[0032] According to some embodiments of the present invention, a current path can be formed by connecting a substrate such that metal layers formed on both sides of an insulating film layer constituting an electrode of a secondary battery are electrically connected to each other.

[0033] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0034]

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0036] FIG. 1 is a side view showing an example of an electrode according to one embodiment of the present disclosure.

[0037] FIG. 2 is a front view showing an example of an electrode according to one embodiment of the present disclosure.

[0038] FIG. 3 is a drawing showing an example of connecting a substrate to a metal layer in an electrode according to one embodiment of the present disclosure.

[0039] FIG. 4 is a side view showing an example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0040] FIG. 5 is a front view showing an example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0041] FIG. 6 is a side view showing another example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0042] FIG. 7 is a front view showing another example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0043] FIG. 8 is a front view showing an example in which a notching portion and a tab are formed in an electrode according to one embodiment of the present disclosure.

[0044] FIG. 9 is a cross-sectional view showing an example of a secondary battery according to one embodiment of the present disclosure.

[0045] FIG. 10 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure.

[0046]

[0047] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0048] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0049] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0050] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0051] 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 used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0052] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0053] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0054] Furthermore, where it is stated that one component is "connected," "coupled," or "connected" to another component, it should be understood that while said components may be directly connected or connected to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "connected" through another component. Additionally, when it is stated that a part is electrically coupled with another part, this includes not only cases where they are directly connected but also cases where they are connected with an intermediate element in between.

[0055] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise. That is, "and / or" includes any combination or any combination of the enumerated items. "C to D" means C or more and D or less, unless specifically stated otherwise.

[0056] The terms used in this specification are intended to describe the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0057] FIG. 1 is a side view showing an example of an electrode according to one embodiment of the present disclosure, and FIG. 2 is a front view showing an example of an electrode according to one embodiment of the present disclosure.

[0058] Referring to FIGS. 1 and 2, an electrode according to one embodiment of the present disclosure may include an insulating film layer (110) made of an insulating material, a first metal layer (121) coated on one side of the insulating film layer (110), a second metal layer (122) coated on the other side of the insulating film layer (110), a first substrate (130) connected to the first metal layer (121), and a second substrate (140) connected to the second metal layer (122) and the first substrate (130) to electrically connect the first metal layer (121), the second metal layer (122), and the first substrate (130).

[0059] The insulating film layer (110) can be made of a polymer material. For example, the insulating film layer (110) can be made of polyethylene terephthalate (PET) resin. Of course, the material of the insulating film layer (110) is not limited to this, and can be made of polyester resins such as polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), or polyethylene naphthalate (PEN).

[0060] Each of the first metal layer (121) and the second metal layer (122) may be coated on the insulating film layer (110) with a metal material such as copper, copper alloy, nickel, or nickel alloy, or coated with a metal material such as aluminum or aluminum alloy. The first metal layer (121) and the second metal layer (122) may be formed of the same metal material and may function as an anode or a cathode.

[0061] The first substrate (130) and the second substrate (140) may be made of a metal foil such as copper, copper alloy, nickel, or nickel alloy, or may be made of a metal foil such as aluminum or aluminum alloy. Of course, they are not limited thereto and may be made of a metal material with excellent electrical conductivity. The first substrate (130) and the second substrate (140) may be made of the same metal material. The first substrate (130) and the second substrate (140) may be made of the same material as the first metal layer (121) and the second metal layer (122).

[0062] In this way, the flexibility and lightness of the electrode (100) can be secured by using an insulating film layer (110) made of a polymer resin. A first metal layer (121) and a second metal layer (122) are coated on both sides of the insulating film layer (110), and a current path can be formed by connecting the first metal layer (121) and the second metal layer (122) to a first substrate (130) and a second substrate (140). Through this, electrical conductivity and battery performance can be secured substantially the same as those of an electrode made of a single metal material.

[0063] The first material (130) can be protruded outward from the first metal layer (121) in a direction (Y) parallel to the winding axis while connected to the first metal layer (121). The second material (140) can be protruded outward from the second metal layer (122) in a direction (Y) parallel to the winding axis while connected to the second metal layer (122). The portions of the first material (130) and the second material (140) protruding outward from the first metal layer (121) and the second metal layer (122) can be connected to each other to form a path for current.

[0064] The second material (140) has one end (141) connected to the second metal layer (122), and after being bent toward the first material (130) while the one end (141) is connected, the other end (142) can be connected to the first material (130).

[0065] The second substrate (140) may be formed such that the length (L2) protruding outward from the second metal layer (122) in a direction (Y) parallel to the winding axis is shorter than the length (L1) of the first substrate (130) protruding outward from the first metal layer (121). That is, the second substrate (140) can function to form a current path by electrically connecting the second metal layer (122) and the first substrate (130). In one embodiment, the length of the second substrate (140) in a direction parallel to the winding axis may be formed to be 30 to 60% of the length of the first substrate (130). Of course, the length of the second substrate (140) is not limited to this, and it may be formed to any length as long as it can be connected to the first substrate (130) while connected to the second metal layer (122).

[0066] The first substrate (130) and the second substrate (140) can be connected to the first metal layer (121) and the second metal layer (122) through ultrasonic welding. Of course, this is not limited thereto, and they can be connected through known joining methods such as laser welding or conductive adhesive. Below, an embodiment in which the first substrate (130) and the second substrate (140) are connected to the first metal layer (121) and the second metal layer (122) through ultrasonic welding will be described.

[0067] FIG. 3 is a drawing showing an example of connecting a substrate to a metal layer in an electrode according to one embodiment of the present disclosure. FIG. 4 is a side view showing an example of a substrate being welded to a metal layer in an electrode according to one embodiment of the present disclosure, and FIG. 5 is a front view showing an example of a substrate being welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0068] Referring to FIG. 3, in one embodiment, a first substrate (130) and a second substrate (140) can be connected to a first metal layer (121) and a second metal layer (122) through ultrasonic welding. A substrate having a first metal layer (121) and a second metal layer (122) formed on both sides of an insulating film layer (110) can be loaded into a horn (11) and an anvil (12), which are ultrasonic welding machines, and the first substrate (130) and the second substrate (140) can be loaded together and connected or joined by ultrasonic welding. At this time, the first substrate (130), which is relatively wide, can be loaded toward the anvil (12) so that it can be supported from below, and the second substrate (140), which is relatively narrow, can be loaded toward the horn (11) so that they can be ultrasonic welded.

[0069] Through such ultrasonic welding, the first substrate (130), the first metal layer (121), and one end (141) of the second substrate (140) and the second metal layer (122) are simultaneously connected, and then the other end (142) of the second substrate (140) can be connected to the first substrate (130).

[0070] Referring to FIGS. 4 and 5, a first connecting part (151) in which one end (141) of a first substrate (130), a first metal layer (121), a second metal layer (122), and a second substrate (140) are integrally connected can be formed by ultrasonic welding. Then, a second connecting part (152) in which the other end (142) of the first substrate (130) and the second substrate (140) are integrally connected can be formed by ultrasonic welding. At this time, the first connecting part (151) can be formed by ultrasonic welding first, and then the second connecting part (152) can be formed by ultrasonic welding. Alternatively, the first connecting part (151) and the second connecting part (152) can be formed simultaneously by ultrasonic welding.

[0071] Here, the first connecting part (151), to which one end (141) of the first substrate (130) and the second substrate (140) is connected, can be ultrasonically welded to have a connecting width (W1) of 1 to 2 mm. And, the second connecting part (152), to which the other end (142) of the first substrate (130) and the second substrate (140) is connected, can be ultrasonically welded to have a connecting width (W2) of 1 to 2 mm. Of course, the numerical value of the connecting width is not limited to this, and may vary depending on various conditions such as the thickness of the insulating film layer (110), the first metal layer (121), the second metal layer (122), the first substrate (130), and the second substrate (140), and the overlapping area of ​​the first substrate (130) and the second substrate (140).

[0072] FIG. 6 is a side view showing another example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure, and FIG. 7 is a front view showing another example in which a substrate is welded to a metal layer in an electrode according to one embodiment of the present disclosure.

[0073] Referring to FIGS. 6 and 7, the first substrate (130) is connected to the first metal layer (121), and one end (141) of the second substrate (140) is connected to the second metal layer (122), and at the same time, the first substrate (130) can be connected to the other end (142) of the second substrate (140). In one embodiment, the front surface of the second substrate (140) can be ultrasonically welded while being pressed by a horn. That is, the first substrate (130), the first metal layer (121), the second metal layer (122), and the front surface of the second substrate (140) can be integrally connected to a third connecting part (153) which can be simultaneously formed by ultrasonically welding.

[0074] Here, the third connecting portion (153) connecting the first substrate (130) and the second substrate (140) can be ultrasonically welded to have a connecting width (W3) of 2 to 4 mm. Of course, the numerical value of the connecting width is not limited to this, and may vary depending on various conditions such as the thickness of the insulating film layer (110), the first metal layer (121), the second metal layer (122), the first substrate (130), and the second substrate (140), or the size of the second substrate (140).

[0075] FIG. 8 is a front view showing an example in which a notching portion and a tab are formed in an electrode according to one embodiment of the present disclosure.

[0076] Referring to FIG. 8, the first substrate (130) may be formed in an area where the second substrate (140) is not connected and may include a plurality of bendable tabs (131). That is, after connecting the first substrate (130) and the second substrate (140), a portion of the first substrate (130) may be cut to form a plurality of individually bendable tabs (131). In one embodiment, the plurality of tabs (131) may be formed by laser notching the first substrate (130). Of course, the plurality of tabs (131) may also be formed by known cutting methods such as ultrasonic cutting or stamping.

[0077] A plurality of tabs (131) can be bent toward the winding axis, which is the winding end (RS), while the electrode is wound. At this time, the plurality of tabs (131) can be bent at a point (BP) that is 70 to 80% in the direction (Y) parallel to the winding axis from the outer end. That is, the second material (140) may not be bent. Also, the plurality of tabs (131) can partially overlap each other while in the bent state. Through this, a path for current can be formed.

[0078] A notching portion (160) may be formed by cutting a first substrate (130) or a first substrate (130) and a second substrate (140) in a direction (X) parallel to the winding direction at the winding end (RS). A notching portion (160) may be formed by cutting a portion at the winding end (RS) so that the tap (131) does not shield the hollow formed in the center when the electrode is wound. Although FIG. 8 illustrates a state in which the notching portion (160) is formed by cutting the first substrate (130) and the second substrate (140), it is not limited thereto, and the notching portion (160) may also be formed by cutting only the first substrate (130).

[0079] Also, the length (NL) of the notching portion (160) in the direction (X) parallel to the winding direction may be 5 to 10% of the length (EL) of the insulating film layer (110). Of course, the length (NL) of the notching portion (160) is not limited to this and may vary depending on various conditions such as the length of the tab (131) and the thickness of the electrode.

[0080] FIG. 9 is a cross-sectional view showing an example of a secondary battery according to one embodiment of the present disclosure, and FIG. 10 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure.

[0081] Referring to FIG. 9, a secondary battery according to one embodiment of the present disclosure may include an electrode assembly (400) that performs charging and discharging, a case (520) that houses the electrode assembly (400), a first current collector plate (530) and a second current collector plate (550) connected to the electrode assembly (400), an electrode terminal (541), a vent cap plate (542), and a sealing member (560). In FIG. 9, the vent cap plate (542) is shown positioned on the upper part of the secondary battery and the electrode terminal (541) is shown positioned on the lower part of the secondary battery, but is not limited thereto. Depending on the usage environment or requirements of the secondary battery, the vent cap plate (542) and the electrode terminal (541) may be changed to be positioned on the lower part and the upper part of the secondary battery, respectively.

[0082] The electrode assembly (400) can be formed into a cylindrical jelly roll shape with an empty core by winding the first electrode (100), the separator (300), and the second electrode (200). The first electrode (100) and the second electrode (200) may include a composite layer in which an active material is applied to both sides of the substrate, and an uncoated portion (130, 230) in which the substrate is exposed and the active material is not applied.

[0083] The first electrode (100) may be an electrode corresponding to the positive or negative electrode in a secondary battery. The second electrode (200) may be an electrode corresponding to the opposite electrode to the first electrode (100). For example, if the first electrode (100) is a positive electrode, the second electrode (200) may be a negative electrode. Conversely, if the first electrode (100) is a negative electrode, the second electrode (200) may be a positive electrode.

[0084] The case (520) is formed as a cylinder to house the electrode assembly (400), and the electrode terminal (541) and the vent cap plate (542) may be provided at each axial end of the case (520) so as to face each other.

[0085] The electrode terminal (541) is connected to the first electrode (100) via the first current collector plate (530) through the rivet portion (543), and the case (520) can be connected to the second electrode (200) via the second current collector plate (550). At this time, the vent cap plate (542) may be electrically separated from the second current collector plate (550) and the case (520) and may not have polarity. Of course, it is not limited to this, and if necessary, the vent cap plate (542) may be configured to have polarity by being electrically connected to the second current collector plate (550) or the case (520).

[0086] An electrode terminal (541) connected to the first electrode (100) of the electrode assembly (400) inserted into the case (520) from the outside may be installed on one side of the case. The case (520) may be provided with a through hole (521) that is partially open on one side.

[0087] In one embodiment, the electrode terminal (541) may be installed in a through hole (521) of the case (520) in a riveted structure. To this end, the electrode terminal (541) may be connected to a riveted portion (543). One end of the riveted portion (543) is welded to the first current collector plate (530) and may be positioned to pass through the through hole (521). The electrode terminal (541) may be connected to the riveted portion (543) and positioned on the outside of the case (520). The electrode terminal (541) may be formed to protrude above the outer surface of the case (520) around the through hole (521) and used as an anode terminal. At this time, the first current collector plate (530) becomes an anode current collector plate.

[0088] At this time, the first current collector plate (530) can be electrically connected to the unoccupied portion (130) of the first electrode through the rivet portion (543) and electrically and mechanically connected to the electrode terminal (541). The first current collector plate (530) can be electrically connected to the electrode terminal (541) in a structure that reduces resistance by contacting most of the unoccupied portion (130) of the first electrode. The rivet portion (543) included in the electrode terminal (541) can be installed in a state of electrical insulation from the case (520) while forming a hermetic structure against the electrolyte by interposing a gasket (523) in the through hole (521).

[0089] Here, the gasket (523) may be made of a polymer comprising ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or a combination thereof.

[0090] As another example, the gasket (523) 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 (523) is not limited to the materials listed above and may include various materials with excellent plasticity and insulation properties depending on the choice.

[0091] In one embodiment, the first current collector plate (530) may include a metal plate (531) having at least one bridge (532) formed thereon. The first current collector plate (530) may be composed of a conductive metal, specifically a conductive metal such as nickel, aluminum, copper, silver, zinc, tin, stainless steel (e.g., SUS), or nickel-plated steel or a combination thereof (alloy). Additionally, the metal plate (531) and the bridge (532) constituting the first current collector plate (530) may both be integrally formed from the same material.

[0092] The bridge (532) of the first collector plate (530) can be configured to break when a current exceeding a set value flows. In one embodiment, the bridge (532) normally operates as part of a circuit through which current flows, but when a current exceeding the necessary amount flows, it can act as a fuse that melts due to the heat generated to cut off the circuit.

[0093] An insulating tape (545) may be attached to one side of the first current collector plate (530). The insulating tape (545) may be interposed between the first current collector plate (530) and the case (520) or between the uninsulated portion (130) of the first electrode (100) and the case (520) to perform the function of electrically insulating each component. In one embodiment, the central portion of the insulating tape (545) may include a perforation (546) corresponding to the shape of the rivet portion (543) so that the rivet portion (543) can come into contact with the first current collector plate (530). Additionally, the insulating tape (545) may include a side wall (547) to wrap around a part of the electrode assembly (400).

[0094] Additionally, the case (520) may include a fully open opening (522) so that the electrode assembly (400) can be inserted into the other side. The vent cap plate (542) can seal the opening (522) after the electrode assembly (400) is inserted into the case (520).

[0095] At this time, the second current collector plate (550) can be electrically connected to the non-electrical portion (230) of the second electrode (200) and electrically connected to the case (520). The second current collector plate (550) can be connected to the case (520) in a structure that reduces resistance by contacting most of the non-electrical portion (230) of the second electrode (200).

[0096] The second current collector plate (550) may include a bottom portion (551) welded to the non-bonded portion (230) of the second electrode (200) and a wing portion (552) formed adjacent to the bottom portion (551) and welded to the beading portion (529). The second current collector plate (550) is formed by cutting and bending a circular plate, and may have a plurality of bottom portions (551) and wing portions (552), respectively, and may be arranged alternately along the circumferential direction. In one embodiment, the wing portion (552) may be formed by repeatedly bending the electrode assembly (400) in the axial direction and bending it in the radial direction.

[0097] In one embodiment, when the uncoated portion (230) of the second electrode (200) and the bottom portion (551) of the second current collector plate (550) are welded, a welding line may be formed in the diameter direction of the second current collector plate (550) on the bottom portion (551). Thus, the bottom portion (551) may be evenly connected along the circumferential direction in the area of ​​the uncoated portion (230) of the second electrode (200), and the wing portion (552) may be evenly connected along the circumferential direction in the area of ​​the beading portion (529). Through this, a uniform flow of current may be formed along the circumferential direction in the entire area of ​​the uncoated portion (230) and the beading portion (529) of the second electrode (200).

[0098] The second current collector plate (550) is provided with a hole (553) in the center, so that deformation caused by welding between the bottom part (551) and the non-bonded part (230) of the second electrode, and vibrations and shocks that may be transmitted between the wing part (552) and the bottom part (551) can be absorbed and mitigated. The hole (553) may have a size within a range that allows vibrations and shocks to be absorbed without increasing current resistance between the wing part (552) and the bottom part (551). Although an embodiment in which a hole (553) is formed in the second current collector plate (550) has been described, it is not limited thereto, and a hole (553) may not be formed in the second current collector plate (550) as needed.

[0099] The vent cap plate (542) is electrically separated from the second current collector plate (550) and can be installed in the opening (522) of the case (520) by a clamping process. Alternatively, the vent cap plate (542) can be installed in the opening (522) of the case (520) through a welding process. Due to the connection of the second current collector plate (550), the case (520) can be used as a negative terminal. At this time, the second current collector plate (550) becomes a negative current collector plate.

[0100] A notch (544) may be formed on the inner surface of the vent cap plate (542). The notch (544) can be cut to release internal pressure of the secondary battery to the outside in the event of an abnormal event in the secondary battery, thereby preventing a secondary explosion. The notch (544) can be easily cut by receiving concentrated internal pressure during an abnormal event. The notch (544) may be formed over the entire area along the circumferential direction of the vent cap plate (542), or it may be formed in multiple locations spaced apart at set intervals.

[0101] The sealing member (560) may be interposed between the second current collector plate (550) and the vent cap plate (542) and between the second current collector plate (130) and the case (520), and may be fastened by a beading portion (529) or a clamping process. Additionally, the sealing member (560) may form an airtight structure against the electrolyte between the second current collector plate (130) and the opening (522) of the case (520).

[0102] In one embodiment, the sealing member (560) 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 be any one of the suitable compounds used as insulating materials in the art.

[0103] The electrode assembly (400) may include a first electrode (100), a second electrode (200), and a separator (300) disposed between the first electrode (100) and the second electrode (200).

[0104] In addition, at least one of the first electrode (100) and the second electrode (200) may be composed of a multilayer substrate or composite substrate formed by coating metal layers on both sides of an insulating film layer. The multilayer substrate or composite substrate may be composed of the electrodes described with reference to FIGS. 1 to 8.

[0105] Accordingly, at least one of the first electrode (100) and the second electrode (200) may include an insulating film layer (110) made of an insulating material, a first metal layer (121) coated on one side of the insulating film layer (110), a second metal layer (122) coated on the other side of the insulating film layer (110), a first substrate (130) connected to the first metal layer (121), and a second substrate (140) connected to the second metal layer (122) and the first substrate (130) to electrically connect the first metal layer (121), the second metal layer (122), and the first substrate (130).

[0106] In one embodiment, when the first electrode (100) is formed from a composite substrate and functions as an anode, the first metal layer (121) and the second metal layer (122) may be coated with a metal material such as aluminum or an aluminum alloy. Additionally, the first substrate (130) and the second substrate (140) may be made of a metal foil such as aluminum or an aluminum alloy. Of course, the first substrate (130) and the second substrate (140) are not limited thereto and may be made of a metal material with excellent electrical conductivity.

[0107] Alternatively, if the first electrode (100) is formed of a composite substrate and functions as a cathode, the first metal layer (121) and the second metal layer (122) may be coated with a metal material such as copper, a copper alloy, nickel, or a nickel alloy. Also, the first substrate (130) and the second substrate (140) may be made of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. Of course, the first substrate (130) and the second substrate (140) are not limited thereto and may be made of a metal material with excellent electrical conductivity. The first substrate (130) and the second substrate (140) may also be made of the same metal material.

[0108] Of course, the second electrode (200) can also be formed from a composite substrate and function as an anode or a cathode, and may be configured in the same way as the first electrode (100) described above. Since the shape and combined state of the first substrate (130) and the second substrate are the same as those described with reference to FIGS. 1 to 8, a detailed description thereof is omitted.

[0109] FIG. 10 is a drawing in which a first electrode (100) is formed from a composite substrate to form an electrode assembly. A plurality of tabs (131) are formed on the first substrate (130) of the first electrode (100), and the plurality of tabs (131) can be bent and partially overlapped with one another. The plurality of overlapping tabs (131) can be pressed by a compactor jig. The configuration of the first substrate (130) formed in this way may correspond to the uncoated portion (130) of the first electrode (100) described with reference to FIG. 9. Of course, although not shown in the drawing, the uncoated portion (230) of the second electrode (200) may also be configured in the same form.

[0110] Additionally, the multiple tabs (131) can be bent in the winding axis direction (Y) so that the second material (140) is positioned on the inside. That is, the second material (140) can be positioned on the inside with respect to the winding axis direction (Y), and the first material (130) can be positioned on the outside with respect to the winding axis direction (Y). In this way, when the tabs (131) are bent with the second material (140) positioned on the inside, the connected or bonded area of ​​the first material (130) and the second material (140) is further bonded, so that the bonded area of ​​the first material (130) and the second material (140) is not separated and the bonding force can be maintained. If the tab (131) is bent in the opposite direction so that the second material (140) is positioned on the outside, a force is applied to separate the first material (130) and the second material (140) from each other, and the connected area of ​​the first material (130) and the second material (140) can be separated.

[0111] Also, the point (BP) where the tab (131) is bent can be formed higher than the top of the second substrate (140). Therefore, the second substrate (140) may not be bent. That is, since the area where the first substrate (130) and the second substrate (140) are connected is not bent, damage caused by bending in the connected area can be prevented.

[0112] Although the present invention has been described above by 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 spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. An insulating film layer made of an insulating material; A first metal layer coated on one surface of the insulating film layer; A second metal layer coated on the other side of the insulating film layer; A first substrate connected to the first metal layer; and A second substrate connected to the second metal layer and the first substrate, electrically connecting the first metal layer, the second metal layer, and the first substrate. Electrode including 2. In Paragraph 1, The above second description is, An electrode in which the length protruding outwardly from the second metal layer in a direction parallel to the winding axis is shorter than the length protruding outwardly from the first metal layer of the first material.

3. In Paragraph 1, The above second description is, An electrode, one end of which is connected to the second metal layer and the other end of which is connected to the first substrate.

4. In Paragraph 1, The above second description is, An electrode, having one end connected to the second metal layer, bent toward the first substrate, and then connected to the first substrate.

5. In Paragraph 1, An electrode in which one end of the first substrate, the first metal layer, and the second substrate is simultaneously connected to the second metal layer, and then the other end of the second substrate is connected to the first substrate.

6. In Paragraph 5, One end of the first substrate and the second substrate is ultrasonically welded to have a connection width of 1 to 2 mm, forming an electrode.

7. In Paragraph 5, The other end of the first and second materials is ultrasonically welded to have a connection width of 1 to 2 mm, forming an electrode.

8. In Paragraph 1, An electrode in which the first substrate is connected to the first metal layer and one end of the second substrate is connected to the second metal layer, and at the same time the first substrate is connected to the other end of the second substrate.

9. In Paragraph 8, The electrode, wherein the first substrate and the second substrate are ultrasonically welded to have a connection width of 2 to 4 mm.

10. In Paragraph 1, The above second description is, An electrode having a length in a direction parallel to the winding axis that is 30 to 60% of the length of the first substrate.

11. In Paragraph 1, The above first description is, A plurality of bendable tabs are formed in an area where the above-mentioned second material is not connected. Electrode including 12. In Paragraph 11, The above plurality of tabs are, An electrode that is bent at a point 70 to 80% in a direction parallel to the winding axis from the outer end.

13. In Paragraph 1, A notching portion formed by cutting the first substrate or the first substrate and the second substrate in a direction parallel to the winding direction at the winding tip. Electrode including 14. In Paragraph 13, The above notching part is, An electrode having a length in a direction parallel to the winding direction that is 5 to 10% of the length of the insulating film layer.

15. An electrode assembly having a first electrode, a second electrode, and a separator wound thereon; A case having a bottom portion that is open on one side and has a through hole formed on the other side, and in which the electrode assembly is accommodated and electrically connected to the second electrode; A vent cap plate fastened to one open side of the above case; A rivet portion disposed through the above-mentioned through-hole and electrically connected to the first electrode; and A gasket provided in the above-mentioned through hole that electrically insulates the case and the rivet portion Includes, At least one of the first electrode and the second electrode is, Insulating film layer made of insulating material; A first metal layer coated on one surface of the insulating film layer; A second metal layer coated on the other side of the insulating film layer; A first substrate connected to the first metal layer; and A second substrate connected to the second metal layer and the first substrate, electrically connecting the first metal layer, the second metal layer, and the first substrate. A secondary battery including 16. In Paragraph 15, The above second description is, A secondary battery in which the length protruding outwardly from the second metal layer in a direction parallel to the winding axis is shorter than the length protruding outwardly from the first metal layer of the first material.

17. In Paragraph 15, The above second description is, A secondary battery, wherein one end is connected to the second metal layer and the other end is connected to the first substrate.

18. In Paragraph 15, The above first description is, A plurality of bendable tabs are formed in an area where the above-mentioned second material is not connected. A secondary battery including 19. In Paragraph 18, The above plurality of tabs are, A secondary battery in which the above-mentioned second material is folded so as to be placed on the inside.

20. In Paragraph 18, The above plurality of tabs are, A secondary battery bent at 70 to 80% of the way in a direction parallel to the winding axis from the outer end.

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