Electrode, electrode assembly and secondary battery comprising same

Abstract

The present disclosure provides an electrode, an electrode assembly and a secondary battery comprising same. The electrode comprises: a substrate made of a metal material; and a mixture layer formed on a portion of the substrate so as to form an uncoated portion at an end portion of the substrate, wherein the uncoated portion can include: a first uncoated portion formed at the leading end of a winding; and a second uncoated portion, which extends from the first uncoated portion, is higher than the height of the first uncoated portion, and includes a plurality of bendable tabs.

Description

Electrode, electrode assembly, and secondary battery including the same

[0001] The present disclosure relates to an electrode, an electrode assembly, 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] Conventional cylindrical secondary batteries have a structure in which electrode tabs are welded to the uncoated portion of the electrode assembly. In secondary batteries with this structure, the current path is limited and current is concentrated at the electrode tabs, which can lead to heat generation at the tabs and a decrease in current collection efficiency.

[0005] To solve these problems, a secondary battery is proposed in which a non-tap portion of an electrode assembly is notched to form multiple tabs, and the multiple tabs are bent, overlapped, and compacted to form multiple current paths. However, even with this structure, there are regions where no current path is formed, which may lead to a decrease in current collection efficiency.

[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, an electrode assembly, and a secondary battery including the same for solving the above-mentioned problems.

[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 a substrate made of a metal material and a composite layer formed on a part of the substrate to form an uncoated portion at the end of the substrate.

[0012] According to one embodiment of the present invention, the unwound portion may include a first unwound portion formed at the winding end, and a second unwound portion extending from the first unwound portion, formed higher than the height of the first unwound portion, and including a plurality of foldable tabs.

[0013] According to one embodiment of the present invention, the height of the first non-removable portion may be formed higher than the lowest point of the tab.

[0014] According to one embodiment of the present invention, the height of the first unwound portion may be formed to be equal to or higher than the point where the tab is bent when the tab is bent while the substrate is wound.

[0015] According to one embodiment of the present invention, the first non-removable portion may be formed at a height that contacts the inner surface of a folded tab while the substrate is wound.

[0016] According to one embodiment of the present invention, the first non-stick portion may be formed parallel to the composite layer.

[0017] According to one embodiment of the present invention, the first unwound portion may be inclined downward from the winding end toward the second unwound portion.

[0018] According to one embodiment of the present invention, the first blank portion may be formed such that the height of the lowest point when the substrate is wound is equal to or higher than the point where the tab is bent.

[0019] According to one embodiment of the present invention, the first unwound portion may have a step shape in which the height gradually decreases from the winding end toward the second unwound portion.

[0020] According to one embodiment of the present invention, the first blank portion may be formed such that the lowest height of the portion when the substrate is wound is equal to or higher than the point where the tab is bent.

[0021] According to one embodiment of the present invention, the first blank portion may be formed such that the thickness formed in the radial direction while the substrate is wound is equal to or greater than the folded length of the tab.

[0022] According to one embodiment of the present invention, the length of the first bare portion may be 500 mm to 600 mm.

[0023] An electrode assembly according to an embodiment of the present invention for solving the above technical problem comprises a first electrode including a non-solid portion and a first composite layer, a second electrode including a non-solid portion and a second composite layer, and a separator disposed between the first electrode and the second electrode, wherein at least one non-solid portion among the first electrode and the second electrode may include a first non-solid portion formed at the winding tip, and a second non-solid portion extending from the first non-solid portion, formed higher than the height of the first non-solid portion, and including a plurality of tabs.

[0024] According to one embodiment of the present invention, the height of the first unwound portion may be formed to be equal to or higher than the point where the tab is bent when the first electrode, the second electrode, and the separator are wound.

[0025] According to one embodiment of the present invention, the first non-removable portion may be formed at a height that contacts the inner surface of a folded tab in a wound state with the first electrode, the second electrode, and the separator.

[0026] According to one embodiment of the present invention, the first unwound portion may be formed at a height that contacts at least some of the plurality of folded tabs in a wound state of the first electrode, the second electrode, and the separator.

[0027] According to one embodiment of the present invention, the first unwound portion may be formed such that the thickness formed in the radial direction when the first electrode, the second electrode, and the separator are wound is equal to or greater than the folded length of the tab.

[0028] A secondary battery according to an embodiment of the present invention for solving the above 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. At least one of the first electrode and the second electrode may include a first unwound portion formed at the winding end, and a second unwound portion extending from the first unwound portion, formed higher than the height of the first unwound portion, and including a plurality of tabs.

[0029] According to one embodiment of the present invention, the height of the first unwound portion may be formed to be equal to or higher than the point where the tab is bent when the first electrode, the second electrode, and the separator are wound.

[0030] According to one embodiment of the present invention, the first unwound portion may be formed at a height that contacts at least some of the plurality of folded tabs in a wound state of the first electrode, the second electrode, and the separator.

[0031] According to one embodiment of the present invention, the first unwound portion may be formed such that the thickness formed in the radial direction when the first electrode, the second electrode, and the separator are wound is equal to or greater than the folded length of the tab.

[0032]

[0033] According to some embodiments of the present invention, a current path can be formed even in an area where a tab is not formed in the non-existent portion of the negative or positive electrode in an electrode assembly of a secondary battery.

[0034] 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.

[0035]

[0036] 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.

[0037] FIG. 1 is a drawing showing an example of an electrode according to one embodiment of the present disclosure.

[0038] FIG. 2 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure.

[0039] Figure 3 is a diagram showing a comparative example of electrodes.

[0040] Figure 4 is a drawing showing a comparative example of an electrode assembly.

[0041] FIG. 5 is a drawing showing an example of an electrode according to one embodiment of the present disclosure.

[0042] FIG. 6 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure.

[0043] FIG. 7 is a drawing showing an example of an electrode according to another embodiment of the present disclosure.

[0044] FIG. 8 is a drawing showing an example of an electrode assembly according to another embodiment of the present disclosure.

[0045] FIG. 9 is a drawing showing an example of an electrode according to another embodiment of the present disclosure.

[0046] FIG. 10 is a drawing showing an example of an electrode assembly according to another embodiment of the present disclosure.

[0047] FIG. 11 is a cross-sectional view showing an example of a secondary battery according to one embodiment of the present disclosure.

[0048]

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0059] FIG. 1 is a drawing showing an example of an electrode according to one embodiment of the present disclosure, and FIG. 2 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure. FIG. 3 is a drawing showing a comparative example of an electrode, and FIG. 4 is a drawing showing a comparative example of an electrode assembly.

[0060] Referring to FIGS. 1 and 2, an electrode (100) according to one embodiment of the present disclosure may include a substrate (110) made of a metal material and a composite layer (120) formed on a part of the substrate (110) to form a non-coated portion at the end of the substrate (110). That is, on one or both sides of the substrate (110), a composite layer (120) coated with a composite and a non-coated portion not coated with the composite layer (120) may be formed. The non-coated portion may include a first non-coated portion (131) formed at the winding end (RS) and a second non-coated portion (132) formed with a plurality of foldable tabs (132a) extending from the first non-coated portion (131).

[0061] Here, the height (H2) of the second blank section (132) can be formed higher than the height (H1) of the first blank section (131). Also, the height (H1) of the first blank section (131) can be formed higher than the lowest point (TE) of the tab (132a). Therefore, the first blank section (131) can be formed higher than the lowest point (TE) of the tab (132a) formed in the second blank section (132), and lower than the height of the second blank section (132).

[0062] A plurality of tabs (132a) may be formed by cutting a portion of the second bare portion (132) in the height direction, as shown in FIG. 1. In one embodiment, a plurality of tabs (132a) may be formed by laser notching the second bare portion (132). Of course, a plurality of tabs (132a) may also be formed by known cutting methods such as ultrasonic cutting or stamping. A plurality of tabs (132a) may partially overlap each other while being bent toward the winding axis, which is the winding end (RS).

[0063] The second uncut portion (132) may include an uncut area in the lowest portion adjacent to the composite layer (120) in the height direction. The first uncut portion (131) may be formed higher than the area in the second uncut portion (132) where a plurality of tabs (132a) are not formed.

[0064] When the electrode (100) formed in this way is wound to form an electrode assembly (400), the first unwound portion (131) where a plurality of tabs (132a) are not formed can come into contact with the bent tabs (132a) to form a current path.

[0065] In one embodiment, the electrode assembly (400) may include a first electrode (100) comprising a non-solid portion and a first composite layer, a second electrode (200) comprising a non-solid portion and a second composite layer, and a separator (300) disposed between the first electrode and the second electrode. For convenience of explanation, the configuration of the non-solid portion will be described in detail below based on the first electrode (100). A non-solid portion having the same configuration may also be formed in the second electrode (200).

[0066] The unwound portion of the first electrode (100) may include a first unwound portion (131) formed at the winding end (RS), and a second unwound portion (132) that extends from the first unwound portion (131), includes a plurality of tabs (132a), and is formed higher than the height of the first unwound portion (131).

[0067] The electrode assembly (400) can be manufactured by stacking the first electrode (100), the separator (300), and the second electrode (200), winding them around the winding end (RS), folding a plurality of tabs (132a) toward the winding end (RS) to overlap them, and then pressing the overlapped tabs (132a) using a compactor jig.

[0068] The height (H1) of the first unwound section (131) is formed to be at least equal to or higher than the point (BP) where the tab (132a) is bent, so that it can come into contact with at least some of the plurality of tabs (132a) bent toward the winding end (RS). The inner surface of the tab (132a) bent at the upper end of the first unwound section (131) can come into contact to form a path for current.

[0069] In comparison, with reference to FIGS. 3 and 4, the conventional electrode (10) is formed such that the height (H1) of the first bare portion (11) is the same height as the lowest point (TE) of the tab (12a) formed in the second bare portion (12). A plurality of tabs (12a) can be formed by laser notching in the second bare portion (12), and a portion of the tabs can be cut by laser notching along the winding direction at the winding end to form the first bare portion (11).

[0070] In this way, if the lowest point (TE) of the multiple taps (12a) and the height of the first non-contacting portion (11) are formed to be the same, as shown in FIG. 4, when the multiple taps (12a) are bent, an area where the taps (12a) do not come into contact with the first non-contacting portion (11) may be created. When the taps (12a) are bent, the point (BP) where the taps (12a) are bent may be bent at 60 to 80% of the total length of the taps (12a). That is, the taps may be bent at a point higher than the lowest point (TE) of the taps (12a). Therefore, a large number of areas that do not come into contact with the first non-contacting portion (11), which is formed at the same height as the lowest point (TE) of the taps (12a), may be created, and a large number of areas where a current path is not formed may exist.

[0071] To solve this problem, the present disclosure may be configured such that the height (H1) of the first non-tap portion (131) is formed higher than the lowest point (TE) of the tap (132a) or the bending point (BP) of the tap (132a), so that when the tap (132a) is bent, the inner surface of the tap (132a) contacts the upper end of the first non-tap portion (131) to form a path for current.

[0072] FIG. 5 is a drawing showing an example of an electrode according to one embodiment of the present disclosure, and FIG. 6 is a drawing showing an example of an electrode assembly according to one embodiment of the present disclosure.

[0073] Referring to FIGS. 5 and 6, the first unwound section (131) can be formed parallel to the composite layer (120). That is, the first unwound section (131) can be formed parallel to the winding direction. In this form, when wound around the winding end (RS), the first unwound section (131) can be formed at the same height in the wound state, as shown in FIG. 6.

[0074] The first non-bending portion (131) is formed higher than the bending point (BP) of the tap (132a), so that when the tap (132a) is bent, the inner surface of the tap (132a) comes into contact with the upper end of the first non-bending portion (131), thereby forming a path for current.

[0075] The first unwound portion (131) may be formed such that the thickness (W1) formed in the radial direction while wound is at least equal to or greater than the bent length (W2) of the tab (132a). Here, the bent length (W2) of the tab (132a) may refer to the length in which the tab positioned at the innermost side is bent to cover the upper side of the first unwound portion (131). In this form, even if the tab (132a) is bent toward the hollow (C) formed in the center while the electrode is wound, the tab (132a) may cover only the wound area of ​​the first unwound portion (131) and may not shield the hollow (C). The hollow (C) may be configured so that a welding jig can be inserted for welding and thus is not shielded.

[0076] Preferably, the radial thickness (W1) of the first bare portion (131) in the wound state can be formed to be equal to the bent length (W2) of the tab (132a). Through this, the entire area of ​​the first bare portion (131) can come into contact with the tab (132a) without interference with the hollow (C).

[0077] In one embodiment, the length of the first blank portion (131) may be formed to be 500 mm to 600 mm. Of course, the length of the first blank portion (131) is not limited to this, and the length of the first blank portion (131) may vary depending on the total length of the electrode, the thickness of the electrode, the length of the tab, etc.

[0078] FIG. 7 is a drawing showing an example of an electrode according to another embodiment of the present disclosure, and FIG. 8 is a drawing showing an example of an electrode assembly according to another embodiment of the present disclosure.

[0079] Referring to FIGS. 7 and 8, the first unwound section (131a) can be formed to slope downward from the winding end (RS) toward the second unwound section (132). That is, the first unwound section (131a) can be formed with the highest height at the winding end (RS) and the height can be formed to decrease as it moves toward the second unwound section (132). In this form, when wound around the winding end (RS), as shown in FIG. 8, the first unwound section (131a) can be formed so that its height sequentially decreases toward the second unwound section (132) while wound.

[0080] As the number of overlapping tabs (132a) increases from the first bare section (131a) toward the second bare section (132), the number of overlapping tabs (132a) decreases as the number of overlapping tabs (132a) increases toward the winding end (RS). Therefore, in the area where the number of overlapping tabs (132a) increases, the thickness of the overlapping tabs (132a) becomes thicker. Consequently, in the area where the thickness of the overlapping tabs (132a) is relatively thick, the height of the first bare section (131a) is formed relatively lower, allowing the tabs (132a) to be bent more easily.

[0081] The height of the lowest point (LP) near the second unoccupied portion (132) from the first unoccupied portion (131a) can be formed to be at least equal to or higher than the point (BP) where the tap (132a) is bent. Accordingly, when the tap (132a) is bent, the inner surface of the tap (132a) comes into contact from the lowest point (LP) of the first unoccupied portion (131a), thereby forming a path for current.

[0082] Additionally, the thickness (W1) formed in the radial direction of the first unwound portion (131a) in the wound state may be formed to be at least equal to or greater than the bent length (W2) of the tab (132a). This means that even if the tab (132a) is bent toward the hollow (C) formed in the center in the wound state of the electrode, the tab (132a) may cover only the wound area of ​​the first unwound portion (131a) and not shield the hollow (C).

[0083] FIG. 9 is a drawing showing an example of an electrode according to another embodiment of the present disclosure, and FIG. 10 is a drawing showing an example of an electrode assembly according to another embodiment of the present disclosure.

[0084] Referring to FIGS. 9 and 10, the first unwound section (131b) can be formed in a stepped shape with a decreasing height from the winding end (RS) toward the second unwound section (132). That is, the first unwound section (131b) can be formed in a stepped shape with the highest height at the winding end (RS) and gradually decreasing in height toward the second unwound section (132). In this form, when wound around the winding end (RS), as shown in FIG. 10, the first unwound section (131b) can be formed such that its height gradually decreases toward the second unwound section (132) while wound.

[0085] As the number of overlapping tabs (132a) increases from the first bare section (131b) toward the second bare section (132), the number of overlapping tabs (132a) decreases as the number of overlapping tabs (132a) increases toward the winding end (RS). Therefore, in the area where the number of overlapping tabs (132a) increases, the thickness of the overlapping tabs (132a) becomes thicker. Consequently, in the area where the thickness of the overlapping tabs (132a) is relatively thick, the height of the first bare section (131b) is formed relatively lower, allowing the tabs (132a) to be bent more easily.

[0086] The height of the lowest point (LS) near the second unoccupied part (132) in the first unoccupied part (131b) can be formed to be at least equal to or higher than the point (BP) where the tap (132a) is bent. Accordingly, when the tap (132a) is bent, the inner surface of the tap (132a) comes into contact from the lowest point (LS) of the first unoccupied part (131b), thereby forming a path for current.

[0087] Additionally, the thickness (W1) formed in the radial direction of the first unwound portion (131b) in the wound state may be formed to be at least equal to or greater than the bent length (W2) of the tab (132a). This means that even if the tab (132a) is bent toward the hollow (C) formed in the center in the wound state of the electrode, the tab (132a) may cover only the wound area of ​​the first unwound portion (131b) and not shield the hollow (C).

[0088] FIG. 11 is a cross-sectional view showing an example of a secondary battery according to one embodiment of the present disclosure.

[0089] Referring to FIG. 11, 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. 11, 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.

[0090] 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 each include a composite layer in which an active material is applied to both sides of a substrate formed from a thin metal plate, and an uncoated portion (130, 230) in which the substrate is exposed and the active material is not applied.

[0091] 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.

[0092] In one embodiment, the first electrode (100) may be formed as a positive electrode by coating a positive active material on an aluminum (Al) substrate, and the second electrode (200) may be formed as a negative electrode by coating a negative active material on a copper (Cu) substrate. The uncoated portion (130) of the first electrode and the uncoated portion (230) of the second electrode may each be provided at both ends in the winding axis direction of the electrode assembly (400). A vent cap plate (542) may be disposed on the opposite side of the electrode terminal (541) electrically connected to the uncoated portion (130) of the first electrode.

[0093] 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.

[0094] 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).

[0095] 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.

[0096] 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.

[0097] 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).

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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).

[0103] 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).

[0104] At this time, the second current collector plate (550) can be electrically connected to the non-electrical portion (230) of the second electrode 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).

[0105] 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.

[0106] 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).

[0107] 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 (200), 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.

[0108] 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.

[0109] 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.

[0110] 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).

[0111] 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.

[0112] The electrode assembly (400) may include a first electrode (100) comprising a non-solid portion and a first composite layer, a second electrode (200) comprising a non-solid portion and a second composite layer, and a separator (300) disposed between the first electrode (100) and the second electrode (200).

[0113] In addition, at least one of the first electrode (100) and the second electrode, the non-solid portion (130, 230), may include a first non-solid portion (131) described with reference to FIGS. 1 and 2, and a second non-solid portion (132) extending from the first non-solid portion (131). The second non-solid portion (132) may include a plurality of tabs (132a) and may be formed higher than the height of the first non-solid portion (131). The first non-solid portion (131) may be formed higher than the lowest point (TE) of the tab (132a) or the bending point (BP) of the tab (132a), so that when the tab (132a) is bent, the inner surface of the tab (132a) contacts the upper end of the first non-solid portion (131) to form a current path. Various embodiments of the first non-solid portion and the combined state with the second non-solid portion are identical to those described with reference to FIGS. 1 to 10, so a detailed description thereof is omitted.

[0114] 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. A substrate made of metal material; and A composite layer formed on a part of the above-described material to form a blank portion at the end of the above-described material. Includes, The above-mentioned part is, A first unwound portion formed at the winding tip; and A second bare portion extending from the first bare portion, formed higher than the height of the first bare portion, and including a plurality of bendable tabs. Electrode including 2. In Paragraph 1, The height of the above-mentioned first non-removable part is, An electrode formed higher than the lowest point of the above tab.

3. In Paragraph 1, The height of the above-mentioned first non-removable part is, An electrode formed at the same level as or higher than the point where the tab is bent when the above-mentioned material is wound.

4. In Paragraph 1, The above-mentioned first part of the non-disability section is, An electrode formed at a height that contacts the inner surface of the tab that is bent while the above-mentioned material is wound.

5. In Paragraph 1, The above-mentioned first part of the non-disability section is, An electrode formed parallel to the above composite layer.

6. In Paragraph 1, The above-mentioned first part of the non-disability section is, An electrode inclined downward from the above-mentioned winding tip toward the above-mentioned second non-removable portion.

7. In Paragraph 6, The above-mentioned first part of the non-disability section is, An electrode in which the height of the lowest point when the above-mentioned material is wound is formed to be equal to or higher than the point where the tab is bent.

8. In Paragraph 1, The above-mentioned first part of the non-disability section is, An electrode having a step shape in which the height gradually decreases from the above-mentioned winding tip toward the above-mentioned second non-winding portion.

9. In Paragraph 8, The above-mentioned first part of the non-disability section is, An electrode in which the lowest height of the above-mentioned material when wound is equal to or higher than the point where the tab is bent.

10. In Paragraph 1, The above-mentioned first part of the non-disability section is, An electrode having a thickness formed in the radial direction in the state where the above-mentioned material is wound, which is equal to or greater than the folded length of the above-mentioned tab.

11. In Paragraph 1, The length of the first bare portion mentioned above is, An electrode that is 500 mm to 600 mm long.

12. A first electrode comprising a non-removable portion and a first composite layer; A second electrode comprising a non-reinforced portion and a second composite layer; and A separator disposed between the first electrode and the second electrode. Includes, At least one of the first electrode and the second electrode is a non-water portion, A first unwound portion formed at the winding tip; and A second back portion extending from the first back portion, formed higher than the height of the first back portion, and including a plurality of bendable tabs. An electrode assembly comprising 13. In Paragraph 12, The height of the above-mentioned first non-removable part is, An electrode assembly formed at the same level as or higher than the point where the tab is bent when the first electrode, the second electrode, and the separator are wound.

14. In Paragraph 12, The above-mentioned first part of the non-disability section is, An electrode assembly formed at a height that contacts the inner surface of the folded tab in a wound state, wherein the first electrode, the second electrode, and the separator are wound.

15. In Paragraph 12, The above-mentioned first part of the non-disability section is, An electrode assembly formed at a height that contacts at least some of the plurality of tabs that are folded while the first electrode, the second electrode, and the separator are wound.

16. In Paragraph 12, The above-mentioned first part of the non-disability section is, An electrode assembly in which the thickness formed in the radial direction when the first electrode, the second electrode, and the separator are wound is equal to or greater than the folded length of the tab.

17. An electrode assembly having a first electrode, a second electrode, and a separator wound thereon; A case having a bottom portion with one side open and a through hole formed on the other side, 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 a non-water portion, A first unwound portion formed at the winding tip; and A second back portion extending from the first back portion, formed higher than the height of the first back portion, and including a plurality of bendable tabs. An interest battery containing 18. In Paragraph 17, The height of the above-mentioned first non-removable part is, A secondary battery formed such that when the tab is bent while the first electrode, the second electrode, and the separator are wound, the tab is formed at the same level as or higher than the point where the tab is bent.

19. In Paragraph 17, The above-mentioned first part of the non-disability section is, A secondary battery formed at a height that contacts at least some of the plurality of tabs that are folded while the first electrode, the second electrode, and the separator are wound.

20. In Paragraph 17, The above-mentioned first part of the non-disability section is, A secondary battery in which the thickness formed in the radial direction when the first electrode, the second electrode, and the separator are wound is equal to or greater than the folded length of the tab.

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