Electrode and secondary battery including the same

Abstract

The present disclosure relates to an electrode and a secondary battery including the same. The electrode includes a substrate including a metal material, an active material layer on a first portion of the substrate, a second portion of the substrate without the active material layer being an uncoated portion, an electrode tab at an end of the uncoated portion, and a crimped portion in the uncoated portion between the active material layer and the electrode tab.

Description

Technical Field

[0001] This disclosure relates to an electrode and a secondary battery including the electrode. Background Technology

[0002] Unlike primary batteries, which are not designed for (re)charging, secondary (or rechargeable) batteries are designed for discharging and recharging. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources to drive motors in hybrid and electric vehicles and for storing electrical energy (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly containing positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] The information disclosed above in this background section is intended to enhance understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0004] The embodiments include or provide an electrode comprising: a substrate comprising a metallic material; an active material layer on a first portion of the substrate, wherein a second portion of the substrate without the active material layer is an uncoated portion; an electrode tab at an end of the uncoated portion; and a corrugated portion in the uncoated portion, wherein the corrugated portion is located between the active material layer and the electrode tab.

[0005] The wrinkled portion can be configured to deform to absorb the external force when an external force is applied to the uncoated portion.

[0006] The wrinkled areas can be formed by deforming the uncoated areas.

[0007] The pleated portion may have a curved shape, and at least a portion of the pleated portion protrudes on at least one of the two surfaces of the uncoated portion.

[0008] The pleats can have a wave shape, with the U-shaped part repeating throughout the pleats. The pleats can also have a zigzag shape, with the V-shaped part repeating throughout the pleats.

[0009] The height of the folded portion can be greater than the thickness of the substrate.

[0010] The height of the folded portion can be less than or equal to the thickness of the active material layer.

[0011] The active material layer can be on the opposite surface of the substrate, and the height of the wrinkled portion can be equal to or less than the total thickness of the substrate and the active material layer.

[0012] The height of the folded portion can range from 20 µm to 100 µm.

[0013] The embodiments include or provide a secondary battery, comprising: an electrode assembly including a first electrode, a separator, and a second electrode; a housing housing the electrode assembly; and a cover assembly coupled to an opening in the housing to seal the housing, wherein at least one of the first electrode and the second electrode includes: a substrate comprising a metallic material; an active material layer on a first portion of the substrate, wherein a second portion of the substrate without the active material layer is an uncoated portion; an electrode tab at an end of the uncoated portion; and a corrugated portion in the uncoated portion, wherein the corrugated portion is between the active material layer and the electrode tab.

[0014] The pleated portion can face the inner circumferential surface of the shell, and the diaphragm is located between the pleated portion and the inner circumferential surface of the shell.

[0015] The pleated portion can be configured to expand the first and second electrodes due to the charging and discharging of the electrode assembly, and deform to absorb the external force when an external force is applied to the uncoated portion.

[0016] The cover assembly may include: a cover plate, an opening connected to the housing, the cover plate including a through hole; a terminal plate on the cover plate, the terminal plate including a protrusion in the through hole; and an upper insulator between the cover plate and the terminal plate.

[0017] The first electrode may include: a first substrate, comprising a metallic material; a first active material layer on a first portion of the first substrate, wherein a second portion of the first substrate without the first active material layer is a first uncoated portion; and a first electrode tab at the end of the first uncoated portion, wherein the first electrode tab is electrically connected via a protrusion connected to a terminal plate, wherein a wrinkled portion in the first uncoated portion is between the first active material layer and the first electrode tab, or, the wrinkled portion in the first uncoated portion is between a non-wrinkled portion on a first side of the wrinkled portion of the first uncoated portion and another non-wrinkled portion on a second side of the wrinkled portion opposite to the first side of the first uncoated portion.

[0018] The pleated portion may have a curved shape, and at least a portion of the pleated portion protrudes on at least one of the two surfaces of the uncoated portion.

[0019] The folded parts can have a wave shape or a zigzag shape. The U-shaped part of the wave shape repeats throughout the folded parts, and the V-shaped part of the zigzag shape repeats throughout the folded parts.

[0020] The height of the folded portion can be greater than the thickness of the substrate, and the height of the folded portion can be equal to or less than the thickness of the active material layer.

[0021] The active material layer can be on the opposite surface of the substrate, and the height of the wrinkled portion can be equal to or less than the total thickness of the substrate and the active material layer.

[0022] The height of the folded portion can range from 20µm to 100µm. Attached Figure Description

[0023] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

[0024] Figure 1 Examples of electrodes according to some embodiments of the present disclosure;

[0025] Figure 2 Examples illustrating areas in an electrode where cracks may occur;

[0026] Figure 3 Examples illustrating the state in which electrodes according to some embodiments of the present disclosure are housed in the casing of a secondary battery;

[0027] Figure 4 An example is given of the deformation of the comparative electrode due to external force when it is housed in the casing of a secondary battery;

[0028] Figure 5 Examples of electrodes according to some embodiments of the present disclosure being deformed due to external forces when housed in a secondary battery casing;

[0029] Figure 6 Examples comparing the dimensions of the folded portions in electrodes according to some embodiments of the present disclosure;

[0030] Figure 7 Another example of a wrinkled portion in an electrode according to some embodiments of the present disclosure;

[0031] Figure 8 A cross-sectional view of an example secondary battery according to some embodiments of the present disclosure is shown;

[0032] Figure 9 An exploded perspective view illustrating an example of a secondary battery according to some embodiments of the present disclosure;

[0033] Figure 10 For example, by following along Figure 8 A cross-sectional view of an example obtained by cutting line AA;

[0034] Figure 11 For example Figure 10 A magnified view of an example in area B.

[0035] Explanation of reference numerals in the attached figures

[0036] 100: Secondary battery

[0037] 200: Housing

[0038] 300: Electrode assembly

[0039] 310: Electrode, first electrode

[0040] 311: Substrate, first substrate

[0041] 312: Active substance layer, first active substance layer

[0042] 313: Uncoated portion, first uncoated portion

[0043] 314: Folded parts

[0044] 315: Electrode connector, first electrode connector

[0045] 320: Second electrode

[0046] 325: Second electrode connector

[0047] 330: Diaphragm

[0048] 400: Cover assembly

[0049] 500: Insulating sheet Detailed Implementation

[0050] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementation to those skilled in the art.

[0051] In the accompanying drawings, for clarity, the dimensions of layers and regions may be enlarged. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it may be directly on that other layer or substrate, or an intervening layer may also be present. Furthermore, it will be understood that when a layer is referred to as being "below" another layer, it may be directly below, and one or more intervening layers may also be present. Additionally, it will be understood that when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or one or more intervening layers may also be present. The same reference numerals refer to the same elements throughout the drawings.

[0052] The terms or words used in this specification and claims should not be limited to their general or dictionary meanings, and should be understood based on the principle that the inventor can be his / her own lexicographer to properly define terms and concepts for the purpose of best describing his / her disclosure, and should be interpreted as meanings and concepts consistent with the technical ideas of this disclosure.

[0053] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some embodiments of this disclosure and do not represent all the technical spirit, aspects, and features of this disclosure. Accordingly, it should be understood that various equivalents and modifications may exist at the time of filing this application, and the embodiments described herein may be replaced or modified.

[0054] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to," or "linked to" another element or layer, it may be directly on, connected to, or linked to the other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to," or "directly linked to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "linked" or "connected" to a second element, the first element may be directly linked to or connected to the second element, or the first element may be indirectly linked to or connected to the second element via one or more intermediary elements.

[0055] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated enumerated items. Furthermore, the use of "may" in describing embodiments of this disclosure refers to "one or more embodiments of this disclosure." Expressions such as "at least one of..." and "any one of..." modify the entire list of elements without modifying individual elements in the list when placed before / after the list of elements. When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group of A, B, and C," or "at least one selected from A, B, and C" are used to denote a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “using,” and “used” are to be regarded as synonyms with the terms “utilize,” “utilizing,” and “utilized,” respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to describe the inherent variations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0056] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, areas, layers, and / or segments, these elements, components, areas, layers, or segments should not be limited by these terms. These terms are used to distinguish one element, component, area, layer, or segment from another. Therefore, the first element, component, area, layer, or segment discussed below may be referred to as the second element, component, area, layer, or segment without departing from the teachings of the exemplary embodiments.

[0057] For ease of description, spatial relative terms, such as “below,” “under,” “down,” “above,” and “above,” are used herein to describe the relationship of one element or feature to another element or feature illustrated in the figures. It will be understood that, in addition to the orientation depicted in the figures, spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features will be oriented “above” or “above” other elements or features. Thus, the term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein should be interpreted accordingly.

[0058] The terminology used herein is for describing embodiments of this disclosure and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are intended to also include the plural forms. It will be further understood that the terms “includes,” “including,” “comprises,” and / or “comprising,” when used in this specification, indicate the presence of said features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0059] Furthermore, any numerical range disclosed and / or set forth herein is intended to include all subranges with the same numerical precision contained within the set forth range. For example, the range “1.0 to 10.0” is intended to include all subranges between the set forth minimum value of 1.0 and the set forth maximum value of 10.0, i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits contained herein, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits contained herein. Accordingly, the applicant reserves the right to amend this specification (including the claims) to expressly set forth any subranges contained within the range expressly set forth herein. All such ranges are intended to be described inherently in this specification such that any amendment to expressly set forth any of these subranges will comply with the requirements of local patent law.

[0060] Referring to two compared elements, features, etc., as "identical" can mean that they are "substantially identical." Therefore, the phrase "substantially identical" can include situations in the art where the deviation is considered low, for example, a deviation of 5% or less. Additionally, when a parameter is described as uniform in a given region, this can mean that it is uniform in terms of its average value.

[0061] Throughout the manual, unless otherwise stated, each element may be singular or plural.

[0062] Placing any element "above (or below)" or "above (or below)" another element can mean that the arbitrary element can be configured to contact the upper (or lower) surface of the element, and that the other element can be inserted between the element and any element disposed on (or below) the element.

[0063] Additionally, it will be understood that when a component is referred to as a “connection,” “link,” or “attachment” to another component, these components may be directly “connected,” “linked,” or “attached” to each other, or another component may be “inserted” between the components.

[0064] Throughout the instruction manual, unless otherwise stated, when “A and / or B” is mentioned, it means A, B, or A and B. That is, “and / or” includes any or all combinations of the listed items. Unless otherwise indicated, when “C~D” is mentioned, it means greater than or equal to C and less than or equal to D.

[0065] Figure 1 Examples of electrodes according to some embodiments of the present disclosure are illustrated, and Figure 2 An example illustrating a region in an electrode where cracks may occur.

[0066] refer to Figure 1 and Figure 2According to some embodiments of the present disclosure, the electrode 310 may include: a substrate 311, including a metallic material; an active material layer 312 formed on a portion (e.g., a first portion) of the substrate 311 to form an uncoated portion 313 (e.g., a second portion of the substrate 311 without the active material layer 312 may be an uncoated portion 313); an electrode tab 315 formed at the end of the uncoated portion 313; and a wrinkled portion 314 formed in the uncoated portion 313 between the active material layer 312 and the electrode tab 315.

[0067] The substrate 311 is a current collector formed of a metallic material and may be in the form of a thin metal plate or a metal film. In some embodiments, the substrate 311 may be formed of aluminum foil or copper foil.

[0068] An active material layer 312 may be formed on a portion (e.g., a first portion) of a substrate 311, such that an uncoated portion 313 is formed at the end of the substrate 311 without the active material layer 312 (e.g., a second portion). The active material layer 312 may be formed on both surfaces (or opposite surfaces) of the substrate 311. In some embodiments, a first active material layer 312a may be formed on one surface of the substrate 311, and a second active material layer 312b may be formed on the other (e.g., opposite) surface. The first active material layer 312a and the second active material layer 312b may be manufactured by coating an electrode mixture comprising an active material, a binder, a conductive material, etc., onto the surface of the substrate 311 and then drying and rolling the electrode mixture.

[0069] The electrode mixture forming the first active material layer 312a and the second active material layer 312b may include the same components. In some embodiments, the electrode mixture may include a positive electrode active material, a binder, a conductive material, etc. In some embodiments, the electrode mixture may include a negative electrode active material, a binder, a conductive material, etc.

[0070] In some embodiments, the length of the first active material layer 312a may be greater than the length of the second active material layer 312b. The first active material layer 312a may be formed first on one surface of the substrate 311, and then the second active material layer 312b may be formed on the other surface of the substrate 311. In some embodiments, after the electrode mixture is applied to one surface of the substrate 311, the electrode mixture may be dried and then planarized by a roll forming process to form the first active material layer 312a. Afterward, the electrode mixture may be applied to the other surface of the substrate 311, dried, and then planarized by a roll forming process to form the second active material layer 312b.

[0071] In some embodiments, after forming a first active material layer 312a on one surface of the substrate 311, during the process of forming a second active material layer 312b on another surface of the substrate 311 by applying and drying an electrode mixture and then rolling the electrode mixture, there may be a point R where the maximum shear stress is applied to the active material layer 312 near the end of the second active material layer 312b. Point R, as the point of application of the maximum shear stress, may induce damage in the active material layer 312 and may be the point where fatigue fracture first occurs. That is, the electrode repeatedly contracts and expands during the lifespan of the secondary battery, and cracks may occur at point R in the active material layer 312, which is the point of application of the maximum shear stress, causing fatigue fracture to advance rapidly and potentially shortening the lifespan of the secondary battery.

[0072] In the electrode 310 according to some embodiments of the present disclosure, by forming a pleated portion 314 in the uncoated portion 313 between the active material layer 312 and the electrode tab 315, the external force applied to the uncoated portion 313 during the repeated contraction and expansion of the electrode during the life cycle of the secondary battery can be absorbed by the deformation of the pleated portion 314 (e.g., causing the pleated portion 314 to be deformable), thereby removing the tensile load applied to the active material layer 312 and preventing damage to the active material layer 312.

[0073] A wrinkled portion 314 is formed in the uncoated portion 313 between the active material layer 312 and the electrode tab 315 to absorb loads or external forces applied to the uncoated portion 313. In some embodiments, the wrinkled portion 314 can be formed by deforming the uncoated portion 313 using an embossing or roller.

[0074] Figure 3 Examples illustrating the state in which electrodes according to some embodiments of the present disclosure are housed in the casing of a secondary battery. Figure 4 An example is given of the deformation of the comparative electrodes due to external forces when housed in the casing of a secondary battery, and... Figure 5 Examples of electrodes according to some embodiments of the present disclosure being deformed due to external forces when housed in the casing of a secondary battery.

[0075] refer to Figure 3 When the electrode is housed in the casing 200 of the secondary battery in a wound state, the gap G1 between the uncoated portion 313 of the substrate 311 and the casing 200 can be formed to be larger than the gap G2 between the active material layer 312 and the casing 200. Therefore, if the electrode expands, a load may be continuously applied to the uncoated portion 313 on which the active material layer 312 is not formed.

[0076] refer to Figure 4For the comparison electrode 10 without wrinkles, once the electrode expands, the active material layer 12 is in close contact with the inner peripheral surface of the housing 20, preventing further deformation. Because the uncoated portion 13 of the substrate 11 on which the active material layer 12 is not formed remains spaced from the inner peripheral surface of the housing 20, the uncoated portion 13 may continuously receive loads toward the housing 20. If the uncoated portion 13 receives a load that deforms it toward the housing 20, a tensile load may be applied to the substrate 11 on which the active material layer 12 is formed. Therefore, if the electrode repeatedly contracts and expands during the secondary battery's lifespan, repeated loads will be applied to the substrate 11 on which the active material layer 12 is formed, causing fatigue fracture to rapidly advance at point R, which is the point of application of maximum shear stress, thereby shortening the secondary battery's lifespan.

[0077] In comparison, reference Figure 5 In the electrodes according to some embodiments of the present disclosure, even if the electrode expands during the lifespan of the secondary battery, causing the active material layer 312 to come into close contact with the inner peripheral surface of the housing 200, a load is applied to the uncoated portion 313 in the direction toward the housing 200, and the wrinkled portion 314 can deform to absorb this load. Accordingly, it is possible to prevent tensile loads from being applied to the side of the substrate 311 on which the active material layer 312 is formed, thereby preventing damage to the active material layer 312.

[0078] Figure 6 Examples comparing the dimensions of the wrinkled portions in electrodes according to some embodiments of the present disclosure, and Figure 7 Another example of a wrinkled portion in an electrode according to some embodiments of the present disclosure is illustrated.

[0079] refer to Figure 6 The wrinkled portion 314 can be formed in a curved shape such that at least a portion of the wrinkled portion 314 protrudes on one or both surfaces of the uncoated portion 313. In some embodiments, the wrinkled portion 314 can be in a wave form (or have a wave shape), with the U-shape in the wave form repeating continuously (e.g., repeating throughout the wrinkled portion 314). However, as Figure 7 As shown, the pleated portion 314a can also be in a zigzag form (or have a zigzag shape), with the V-shape in the zigzag form being repeated continuously (e.g., repeated throughout the pleated portion 314a). That is, the pleated portion 314 can be formed in any shape as long as it can absorb the external force applied to the uncoated portion 313.

[0080] The height (T3) of the wrinkled portion 314 (e.g., measured along a direction perpendicular to the longitudinal direction of the substrate 311) can be greater than the thickness (T1) of the substrate 311 (e.g., measured along a direction perpendicular to the longitudinal direction of the substrate 311), and can be equal to or less than the thickness of the active material layer 312 (e.g., measured along a direction perpendicular to the longitudinal direction of the substrate 311). The height (T3) of the wrinkled portion 314 (e.g., the height (T3) of the wrinkled portion 314 obtained by measuring the distance from peak to peak along the same direction) can refer to the distance between the protruding edges on one or both surfaces of the substrate 311. When the active material layer 312 is formed on both surfaces of the substrate 311, the height (T3) of the wrinkled portion 314 can be equal to or less than the total thickness (T2) of the substrate 311 and the active material layer 312. In some embodiments, the thickness (T1) of the substrate 311 can be 10µm-15µm, and the total thickness (T2) of the substrate 311 and the active material layer 312 can be 100µm. In this case, the height (T3) of the folded portion 314 can be 20µm to 100µm.

[0081] If the height (T3) of the wrinkled portion 314 is less than the thickness (T1) of the substrate 311, the wrinkled portion 314 cannot absorb external forces; and if the height (T3) of the wrinkled portion 314 is greater than the thickness of the active material layer 312 or greater than the total thickness (T2) of the substrate 311 and the active material layer 312 when the active material layer 312 is formed on both surfaces of the substrate 311, the wrinkled portion 314 may press against adjacent electrodes and cause damage to other electrodes.

[0082] Figure 8 A cross-sectional view of an example secondary battery according to some embodiments of the present disclosure is shown below. Figure 9 An exploded perspective view illustrating an example of a secondary battery according to some embodiments of the present disclosure. Figure 10 For example, by following along Figure 8 The example cross-sectional view obtained by cutting line AA, and Figure 11 For example Figure 10 A magnified view of an example in area B.

[0083] refer to Figures 8 to 11 According to some embodiments of the present disclosure, a secondary battery 100 may include: an electrode assembly 300 having a first electrode 310, a separator 330, and a second electrode 320; a housing 200 for receiving the electrode assembly 300; and a cover assembly 400 connected to an opening in the housing 200 to seal the housing 200.

[0084] The electrode assembly 300 may include a diaphragm 330 and a first electrode 310 and a second electrode 320 positioned therebetween when the diaphragm 330 is inserted therebetween, and may be wound into a core shape.

[0085] The first electrode 310 includes a first substrate and a first active material layer on the first substrate. The first electrode tab 315 can extend outward from a first uncoated portion of the first substrate where there is no first active material layer, and the first electrode tab 315 can be electrically connected to the cover assembly 400.

[0086] The second electrode 320 includes a second substrate and a second active material layer on the second substrate. A second electrode tab 325 extends outward from a second uncoated portion of the second substrate where the second active material layer is not present, and the second electrode tab 325 is electrically connected to the housing 200. The first electrode tab 315 and the second electrode tab 325 may extend in opposite directions.

[0087] The first electrode 310 can serve as a positive electrode. In this embodiment, the first substrate can be made of, for example, aluminum foil, and the first active material layer can include, for example, a transition metal oxide. The second electrode 320 can serve as a negative electrode. In this embodiment, the second substrate can be made of, for example, copper foil or nickel foil, and the second active material layer can include, for example, graphite.

[0088] The separator 330 can prevent short circuits between the first electrode 310 and the second electrode 320 while allowing lithium ions to move between them. The separator 330 can be made of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0089] The housing 200 houses the electrode assembly 300 and, together with the cover assembly 400, forms the appearance of the secondary battery. The housing 200 may have a substantially cylindrical body portion and a bottom portion connected to one side (e.g., one end) of the body portion. The housing 200 may be made of a metal such as aluminum, aluminum alloy, or nickel-plated steel.

[0090] The second electrode tab 325 can be electrically connected to the bottom portion of the housing 200. The first electrode tab 315 may have an end portion that connects to the protrusion 421 of the terminal plate 420. An insulating tape 316 may be attached to the portion of the first electrode tab 315 other than the portion where the first electrode tab 315 connects to the protrusion 421 of the terminal plate 420. The insulating tape 316 can be attached because the first electrode tab 315 bent to the upper side of the electrode assembly 300 may contact the cover plate 410 of the cover assembly 400 or the inner peripheral surface of the housing 200, causing a short circuit.

[0091] The cover assembly 400 may include: a cover plate 410 having a through hole 411 formed therein; a terminal plate 420 disposed on the cover plate 410 and including a protrusion 421 inserted into the through hole 411; and an upper insulator 430 disposed between the cover plate 410 and the terminal plate 420.

[0092] The cover plate 410 can be formed in the shape of a disc with a through hole 411 in its center. The cover plate 410 can be formed with a diameter larger than that of the terminal plate 420 and the upper insulator 430. The cover plate 410 can be connected by welding to the upper end of the housing 200 to close one open side (i.e., the opening) of the housing 200. The shape of the cover plate 410 can be formed in various shapes corresponding to the shape of the housing 200 to which it is connected.

[0093] The terminal plate 420 can be formed as a disk shape with a diameter smaller than that of the cover plate 410, and a protrusion 421 can be formed at its center, such that the protrusion 421 is inserted into the through hole 411 of the cover plate 410. With the protrusion 421 of the terminal plate 420 inserted into the through hole 411, the protrusion 421 can protrude toward the electrode assembly 300. The protrusion 421 of the terminal plate 420 can be configured for connection with the first electrode tab 315. The shape of the terminal plate 420 can be formed in various shapes corresponding to the shape of the cover plate 410.

[0094] The protrusion 421 of the terminal block 420 can be connected to the first electrode terminal 315, and the second electrode terminal 325 can be connected to the housing 200, so that the terminal block 420 can be used as a positive electrode and the housing 200 can be used as a negative electrode.

[0095] An upper insulator 430 is disposed between the cover plate 410 and the terminal plate 420, thereby electrically insulating the cover plate 410 from the terminal plate 420. Since the cover plate 410 and the terminal plate 420 are each formed of a conductive metal material and are electrically connected to the second electrode contact 325 (negative electrode) and the first electrode contact 315 (positive electrode), respectively, the upper insulator 430 prevents short circuits by insulating the cover plate 410 from the terminal plate 420. The upper insulator 430 may be formed of a resin such as polypropylene or polyethylene.

[0096] The upper insulator 430 can be formed in a disc shape, with an insertion hole 431 formed at its center, similar to the cover plate 410. Thus, the protrusion 421 of the terminal plate 420 can pass through the insertion hole 431 of the upper insulator 430 and the through hole 411 of the cover plate 410 to be located within the housing 200. The first electrode connector 315 can be connected to the protrusion 421 of the terminal plate 420 within the housing 200. The outer diameter of the upper insulator 430 can be the same as or approximately the outer diameter of the terminal plate 420. The outer diameter of the cover plate 410 can be larger than the outer diameters of the upper insulator 430 and the terminal plate 420. The diameter of the insertion hole 431 of the upper insulator 430 can be the same as or approximately the diameter of the through hole 411 of the cover plate 410.

[0097] The upper insulator 430 can be joined to the cover plate 410 and the terminal plate 420 by heat fusion (by placing the upper insulator 430 between the cover plate 410 and the terminal plate 420 and applying heat and pressure to the cover plate 410 and the terminal plate 420).

[0098] An insulating sheet 500 may be disposed between the cover assembly 400 and the electrode assembly 300 to insulate the upper portion of the electrode assembly 300 from the first electrode terminal piece 315. The insulating sheet 500 may be disposed above the electrode assembly 300 (e.g., between the electrode assembly 300 and the first electrode terminal piece 315). The diameter of the insulating sheet 500 may be smaller than the outer diameter of the electrode assembly 300. The insulating sheet 500 may be formed of a resin such as polypropylene or polyethylene.

[0099] The cover assembly 400 may further include a lower insulator 440 disposed between the cover plate 410 and the first electrode terminal piece 315 to insulate the first electrode terminal piece 315 from the cover plate 410.

[0100] When the cover plate 410 is connected to the housing 200 to act as the same electrode (negative electrode) as the housing 200, the first electrode terminal 315 acts as the positive electrode. Therefore, the lower insulator 440 can insulate the cover plate 410 from the first electrode terminal 315 to prevent short circuits. The lower insulator 440 can be formed of a resin such as polypropylene or polyethylene.

[0101] The lower insulator 440 can be formed in a disc shape with an insertion hole 441 at its center, similar to a cover plate 410. Thus, the protrusion 421 of the terminal plate 420 can pass through the insertion hole 441 of the lower insulator 440 and the through hole 411 of the cover plate 410 to be located within the housing 200. The first electrode tab 315 can be connected to the protrusion 421 of the terminal plate 420. The outer diameter of the lower insulator 440 can be the same as or approximately the outer diameter of the electrode assembly 300. The outer diameter of the lower insulator 440 can be smaller than the outer diameter of the cover plate 410. The size of the insertion hole 441 of the lower insulator 440 can be set such that the cover plate 410 is not exposed on one side of the first electrode tab 315. The diameter of the insertion hole 441 of the lower insulator 440 can be equal to or smaller than the diameter of the through hole 411 of the cover plate 410.

[0102] In some embodiments, the lower insulator 440 may be formed of an insulating tape and attached to the bottom surface of the cover plate 410, or formed of an insulating sheet and connected to the bottom surface of the cover plate 410 by heat fusion.

[0103] refer to Figure 8 and Figure 9 The secondary battery 100 described herein can be a coin-type or button-type battery. However, the secondary battery 100 can also be applied to other types of secondary batteries (e.g., cylindrical batteries). Although Figure 8The diagram shows a configuration where the first electrode tab 315 protrudes upward to connect to the cover assembly 400 and the second electrode tab 325 protrudes downward to connect to the housing 200. However, the first and second electrode tabs may also protrude upward to connect to the cover assembly and the housing, respectively.

[0104] In the electrode assembly 300, at least one of the first electrode 310 and the second electrode 320 may include: a substrate, comprising a metallic material; an active material layer formed on a portion of the substrate (e.g., a first portion) to form an uncoated portion (e.g., a second portion of the substrate without the active material layer may be an uncoated portion); an electrode tab formed at the end of the uncoated portion; and a pleated portion formed in the uncoated portion between the active material layer and the electrode tab.

[0105] In some embodiments, the first electrode 310 can serve as the positive electrode, and the second electrode 320 can serve as the negative electrode. Because the positive and negative electrodes repeatedly contract and expand and accumulate fatigue loads during the lifespan of the secondary battery, the positive electrode may fail before the negative electrode. Therefore, wrinkles can be formed in the first electrode 310, which serves as the positive electrode.

[0106] refer to Figure 1 and Figure 8 The first electrode 310 may include: a first substrate 311 comprising a metallic material; a first active material layer 312 formed on a portion (e.g., a first portion) of the first substrate 311 to form a first uncoated portion 313 (e.g., a second portion of the first substrate 311 without the first active material layer 312 may be the first uncoated portion 313); a first electrode tab 315 formed at the end of the first uncoated portion 313 and electrically connected via a protrusion 421 connected to a terminal block 420; and a pleated portion 314 formed in the first uncoated portion 313 between the first active material layer 312 and the first electrode tab 315. The first electrode 310 may be related to the above. Figures 1 to 3 as well as Figures 5 to 7 The electrode 310 described is the same. In some embodiments, the second electrode 320 may also include a pleated portion.

[0107] refer to Figure 11The pleated portion 314 of the first electrode 310 can be disposed facing the inner peripheral surface of the housing 200, and the separator 330 and the second electrode 320 are inserted between the pleated portion 314 of the first electrode 310 and the inner peripheral surface of the housing 200. In some embodiments, another separator 330 can also be disposed between the second electrode 320 and the inner peripheral surface of the housing 200. If the first electrode 310 and the second electrode 320 expand due to charging and discharging of the electrode assembly 300 during the secondary battery life, and an external force is applied to the first uncoated portion 313, the pleated portion 314 of the first electrode 310 can deform to absorb the external force, thereby removing the tensile load applied to the active material layer and preventing damage to the active material layer.

[0108] According to some embodiments of this disclosure, by forming wrinkles in the uncoated portion of the substrate where no active material layer is formed, any external force generated during the charging and discharging of the secondary battery can be absorbed by the wrinkles.

[0109] Electrodes, serving as both positive and negative electrodes, are manufactured by forming an active material layer on a substrate. During the electrode manufacturing process, weaker regions may be formed within the active material layer. Throughout the secondary battery's lifespan, the electrodes repeatedly contract and expand, and tensile loads are repeatedly applied to the active material layer, potentially inducing cracks in these weaker regions. When cracks appear within the active material layer, it can shorten the secondary battery's lifespan.

[0110] According to some embodiments of this disclosure, by absorbing the external forces generated during the charging and discharging of the secondary battery in the pleated portion, the tensile load applied to the active material layer can be removed, thereby preventing damage to the active material layer.

[0111] Although this disclosure has been described with reference to embodiments and accompanying drawings illustrating various aspects thereof, this disclosure is not limited thereto. Various modifications and variations can be made by those skilled in the art to which this disclosure pertains, within the spirit of the disclosure and within the scope of the claims and their equivalents.

[0112] Example embodiments are disclosed herein, and although specific terminology is used, it is used and interpreted in a general and descriptive sense only and is not intended to be limiting. In some instances, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, as will be apparent to those skilled in the art at the time of filing this application, unless otherwise specifically indicated. Accordingly, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. An electrode, comprising: Substrate, including metallic materials; An active material layer is provided on a first portion of the substrate, and a second portion of the substrate without the active material layer is an uncoated portion. Electrode terminals at the end of the uncoated portion; as well as The wrinkled portion, in the uncoated portion, is located between the active material layer and the electrode tab.

2. The electrode of claim 1, wherein the wrinkled portion is configured to deform to absorb the external force when an external force is applied to the uncoated portion.

3. The electrode according to claim 1, wherein the wrinkled portion is formed by deforming the uncoated portion.

4. The electrode according to any one of claims 1 to 3, wherein the wrinkled portion has a curved shape, and at least a portion of the wrinkled portion protrudes on at least one of the two surfaces of the uncoated portion.

5. The electrode according to claim 4, wherein the pleated portion has a wave shape, and the U-shape in the wave shape is repeated throughout the pleated portion.

6. The electrode according to claim 4, wherein the wrinkled portion has a zigzag shape, and the V-shape in the zigzag shape is repeated throughout the wrinkled portion.

7. The electrode according to any one of claims 1 to 3, wherein the height of the wrinkled portion is greater than the thickness of the substrate.

8. The electrode according to any one of claims 1 to 3, wherein the height of the wrinkled portion is less than or equal to the thickness of the active material layer.

9. The electrode according to any one of claims 1 to 3, wherein: The active material layer is on the opposite surface of the substrate, and The height of the folded portion is equal to or less than the total thickness of the substrate and the active material layer.

10. The electrode according to any one of claims 1 to 3, wherein the height of the wrinkled portion is in the range of 20 µm to 100 µm.

11. A secondary battery, comprising: The electrode assembly includes a first electrode, a diaphragm, and a second electrode; Housing that houses the electrode assembly; as well as A cover assembly, connected to the opening of the housing to seal the housing. Wherein, at least one of the first electrode and the second electrode is an electrode as described in any one of claims 1 and 3 to 10.

12. The secondary battery of claim 11, wherein the pleated portion faces the inner peripheral surface of the housing, and the separator is located between the pleated portion and the inner peripheral surface of the housing.

13. The secondary battery of claim 12, wherein the pleated portion is configured to deform to absorb the external force when the first electrode and the second electrode expand due to the charging and discharging of the electrode assembly and an external force is applied to the uncoated portion.

14. The secondary battery of claim 11, wherein the cover assembly comprises: A cover plate, connected to the opening of the housing, the cover plate including a through hole; Terminal plate, on the cover plate, the terminal plate includes a protrusion in the through hole; as well as An upper insulator is located between the cover plate and the terminal plate.

15. The secondary battery of claim 14, wherein the electrode tab included in the first electrode is electrically connected via the protrusion connected to the terminal plate.

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