Electrode and secondary battery including the same

Abstract

Disclosed are an electrode and a secondary battery including the electrode. The electrode includes: a current collector; a first active material layer on a first surface of the current collector; and a second active material layer on a second surface of the current collector, the second surface being opposite to the first surface, wherein at least one of the first active material layer and the second active material layer includes first pattern portions and second pattern portions alternately arranged in a longitudinal direction of the current collector, wherein the second pattern portions include active material having a higher expansion rate than active material in the first pattern portions during charging, and wherein the second pattern portions are thinner than the first pattern portions.

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 to be (re)charged, secondary (or rechargeable) batteries are designed to be discharged and recharged. 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 for driving motors in hybrid and electric vehicles and for storing electricity (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] Electrode assemblies housed in the casing of a secondary battery can be formed by creating a layer of active material of constant thickness on a current collector to produce positive and negative electrodes, and then stacking or winding the positive and negative electrodes with a separator in between.

[0004] The information disclosed in this background section is intended to enhance the understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0005] According to one or more disclosed embodiments, an electrode includes: a current collector; a first active material layer formed on a first surface of the current collector; and a second active material layer formed on a second surface of the current collector opposite to the first surface. At least one of the first and second active material layers may include a first patterned portion and a second patterned portion that may be alternately arranged in the longitudinal direction of the current collector. The second patterned portion may include an active material having a higher expansion rate during charging than the active material in the first patterned portion, and the second patterned portion may be thinner than the first patterned portion.

[0006] In some embodiments, the first patterned portion may include graphite material.

[0007] In some embodiments, the second patterned portion may include silicon material.

[0008] In some embodiments, the second patterned portion may include graphite material and silicon material.

[0009] In some embodiments, the thickness of the second patterned portion may be set based on the content of the silicon material.

[0010] In some embodiments, the thickness of the second patterned portion may be set such that the maximum thickness of the second patterned portion that expands during charging corresponds to the maximum thickness of the first patterned portion that expands during charging.

[0011] In some embodiments, the second pattern portion may include a plurality of second pattern portions, and the plurality of second pattern portions gradually thicken in the longitudinal direction of the current collector.

[0012] In some embodiments, the second pattern portion may include a plurality of second pattern portions, and the width of the plurality of second pattern portions gradually increases in the longitudinal direction of the current collector.

[0013] In some embodiments, the first patterned portion and the second patterned portion of the first active material layer may each include a first sub-pattern portion or a 1-1 patterned portion and a second sub-pattern portion or a 1-2 patterned portion that can be alternately arranged in the longitudinal direction of the current collector, and the first patterned portion and the second patterned portion of the second active material layer may each include a third sub-pattern portion or a 2-1 patterned portion and a fourth sub-pattern portion or a 2-2 patterned portion that can be alternately arranged in the longitudinal direction of the current collector.

[0014] In some embodiments, the pattern portions 1-2 may be thicker than the pattern portions 2-2.

[0015] In some embodiments, the width of pattern portion 1-2 may be greater than the width of pattern portion 2-2.

[0016] In some embodiments, the second patterned portion may include: a first patterned layer formed on the current collector; and a second patterned layer formed on the first patterned layer, and including an active material having a predetermined or high expansion rate during charging.

[0017] In some embodiments, the first patterned layer may include a graphite material, and the second patterned layer may include a silicon material.

[0018] In some embodiments, the first patterned layer may include a graphite material, and the second patterned layer may include a graphite material and a silicon material.

[0019] In some embodiments, the 1-2 patterned portion may include: a first or 1-1 patterned layer formed on the first surface of the current collector; and a second or 1-2 patterned layer formed on the 1-1 patterned layer and including an active material having a predetermined or high expansion rate during charging; and the 2-2 patterned portion may include: a third or 2-1 patterned layer formed on the second surface of the current collector; and a fourth or 2-2 patterned layer formed on the 2-1 patterned layer and including an active material having a predetermined or high expansion rate during charging.

[0020] In some embodiments, the 1-1 pattern layer and the 2-1 pattern layer may have the same thickness, and the 1-2 pattern layer may be thicker than the 2-2 pattern layer.

[0021] In some embodiments, the 1-2 pattern layer and the 2-2 pattern layer may have the same thickness, and the 1-1 pattern layer may be thicker than the 2-1 pattern layer.

[0022] In some embodiments, the first patterned portion may be formed as a waveform in the longitudinal direction of the current collector, and the second patterned portion may be formed in the valley region of the first patterned portion.

[0023] In some embodiments, the first patterned portion and the second patterned portion of the first active material layer may respectively include a first sub-patterned portion or 1-1 patterned portion formed as a waveform in the longitudinal direction of the current collector and a second sub-patterned portion or 1-2 patterned portion formed in the valley region of the 1-1 patterned portion. The first patterned portion and the second patterned portion of the second active material layer may respectively include a third sub-patterned portion or 2-1 patterned portion formed as a waveform in the longitudinal direction of the current collector and a fourth sub-patterned portion or 2-2 patterned portion formed in the valley region of the 2-1 patterned portion, and the ridge region or protruding region of the 1-1 patterned portion faces the valley region of the 2-1 patterned portion.

[0024] According to one or more embodiments of this disclosure, a secondary battery may include: an electrode assembly including a first electrode, a separator, and a second electrode; a housing housing the electrode assembly and electrically connected to the second electrode; and a cover assembly closing an opening of the housing and electrically connected to the first electrode. The second electrode may include a current collector, a first active material layer formed on a first surface of the current collector, and a second active material layer formed on a second surface of the current collector opposite to the first surface. At least one of the first active material layer and the second active material layer may include a first patterned portion and a second patterned portion that may be alternately arranged in the longitudinal direction of the current collector. The second patterned portion may include an active material having a higher expansion rate during charging than the active material in the first patterned portion, and the second patterned portion may be thinner than the first patterned portion. Attached Figure Description

[0025] The following accompanying drawings illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects and features of the present disclosure. Therefore, the present disclosure should not be construed as limited to the drawings:

[0026] Figure 1 This is a cross-sectional view of an example electrode according to an embodiment of the present disclosure;

[0027] Figure 2 yes Figure 1 A magnified cross-sectional view illustrating a patterned portion of an electrode according to an embodiment of the present disclosure;

[0028] Figure 3 This is a public document Figure 2 A cross-sectional view illustrating how the electrodes expand during charging and discharging;

[0029] Figure 4 This is a cross-sectional view of an example of how a plurality of second patterned portions of an electrode according to an embodiment of the present disclosure gradually thicken in the longitudinal direction of the current collector;

[0030] Figure 5 This is a cross-sectional view illustrating an example of how the width of a plurality of second patterned portions of an electrode according to an embodiment of the present disclosure gradually increases in the longitudinal direction of the current collector;

[0031] Figure 6 This is a cross-sectional view of an example electrode according to another embodiment of the present disclosure;

[0032] Figure 7 This is a cross-sectional view showing the dimensions of a patterned portion of an electrode according to another embodiment of the present disclosure;

[0033] Figure 8This is a cross-sectional view illustrating an example of how the thickness of a patterned portion formed on a corresponding side of a current collector on an electrode differs according to another embodiment of this disclosure;

[0034] Figure 9 This is a cross-sectional view illustrating an example of how the widths of patterned portions formed on the respective sides of the current collector of the electrode differ according to another embodiment of this disclosure;

[0035] Figure 10 This is a cross-sectional view of an example electrode according to yet another embodiment of the present disclosure;

[0036] Figure 11 This is a cross-sectional view showing the dimensions of the patterned portion of the electrode according to yet another embodiment of the present disclosure;

[0037] Figure 12 This is a cross-sectional view illustrating an example of how multiple second patterned portions of an electrode according to another embodiment of the present disclosure gradually thicken in the longitudinal direction of the current collector.

[0038] Figure 13 This is a cross-sectional view illustrating an example of how the width of a plurality of second patterned portions of an electrode according to another embodiment of the present disclosure gradually increases in the longitudinal direction of the current collector;

[0039] Figure 14 This is a cross-sectional view of an example electrode according to another embodiment of the present disclosure;

[0040] Figure 15 This is a cross-sectional view showing the dimensions of the patterned portion of the electrode according to another embodiment of the present disclosure;

[0041] Figure 16 and Figure 17 This is a cross-sectional view illustrating an example of how the thickness of a patterned portion formed on a corresponding side of a current collector of an electrode differs according to another embodiment of this disclosure.

[0042] Figure 18 This is a cross-sectional view illustrating an example of how the width of a patterned portion formed on a corresponding side of a current collector of an electrode differs according to another embodiment of this disclosure;

[0043] Figure 19 This is a cross-sectional view of an example electrode according to yet another embodiment of the present disclosure;

[0044] Figure 20 This is a cross-sectional view of an example electrode according to another embodiment of the present disclosure;

[0045] Figure 21 This is a cross-sectional view of an example electrode according to another embodiment of the present disclosure; and

[0046] Figure 22This is a cross-sectional view used to illustrate an example of a secondary battery according to some embodiments of the present disclosure. Detailed Implementation

[0047] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as having a general or dictionary meaning, and should be interpreted as consistent with the technical spirit of the present disclosure, based on the principle that the inventor is capable of being his / her own lexicographer to appropriately define the terms and concepts in order to best describe his / her invention.

[0048] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some of the embodiments of this disclosure and do not represent all the technical spirit, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications may exist that can replace or modify the embodiments described herein at the time of filing this application.

[0049] It will be understood that when a component or layer is described as being "on," "connected to," or "attached to" another component or layer, it can be directly on, connected to, or attached to the other component or layer, or one or more intermediate components or layers may be present. When a component or layer is described as being "directly on," "directly connected to," or "directly attached to" another component or layer, no intermediate components or layers are present. For example, when a first component is described as being "attached" or "connected" to a second component, the first component can be directly attached to or connected to the second component, or the first component can be indirectly attached to or connected to the second component via one or more intermediate components.

[0050] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity of illustration. The same reference numerals indicate the same elements. As used herein, the term "and / or" includes any and all combinations of one or more associated listed 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..." preceding / following the list of elements modify the entire list of elements, but not individual elements in the list. 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 specify 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 term "use" may be considered synonymous with the term "utilize." As used herein, the terms “roughly,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to account for the inherent variations in measurements or calculations that would be apparent to a person skilled in the art.

[0051] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or segment from another element, component, region, layer, or segment. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment.

[0052] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” are used herein to describe the relationship between one element or feature and another element or feature as shown in the figures. It will be understood that spatial relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features can be oriented as “above” or “above” other elements or features. Thus, the term “below” can encompass both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0053] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to be limiting of this disclosure. As used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly indicates otherwise. It will be further understood that, as used in this specification, the terms “comprising” and / or “including” specify the presence of the stated 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.

[0054] Furthermore, any numerical ranges disclosed and / or enumerated herein are intended to include all subranges with the same numerical precision contained within the enumerated ranges. For example, the range “1.0 to 10.0” is intended to include all subranges between the enumerated minimum value of 1.0 and the enumerated maximum value of 10.0 (and inclusive of both), 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 2.4 to 7.6. Any maximum numerical limit enumerated herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit enumerated in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify this specification, including the claims, to expressly enumerate any subranges contained within the scope expressly enumerated herein. All such ranges are intended to be inherently described in this specification such that modifications made to expressly enumerate any such subranges will be deemed appropriate.

[0055] Referring to two compared elements, features, etc., as “identical” may mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with deviations considered low in the art, such as 5% or less. Furthermore, when a parameter is said to be consistent in a given region, this may mean that it is consistent in terms of its mean.

[0056] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0057] Placing any element "above (or below)" or "above (or below)" another element may mean that the arbitrary element can be positioned to contact the upper (or lower) surface of the element, and other elements may also be positioned between the element and any element disposed on (or below) the element.

[0058] Furthermore, it will be understood that when a component is referred to as “connected,” “linked,” or “attached” to another component, the components can be directly “connected,” “linked,” or “attached” to each other, or another component can be “between” the components.

[0059] Throughout this specification, unless otherwise stated, when “A and / or B” is mentioned, it means A, B, or A and B. In other words, “and / or” includes any or all combinations of the listed items. Unless otherwise indicated, when “C to D” is mentioned, it means C or more and D or fewer.

[0060] Figure 1 This is a cross-sectional view showing an example of an electrode according to an embodiment of the present disclosure, and Figure 2 This is a cross-sectional view showing the dimensions of a patterned portion of an electrode according to an embodiment of the present disclosure. Figure 3 This is a cross-sectional view illustrating an example of how an electrode according to an embodiment of the present disclosure expands during charging and discharging.

[0061] refer to Figures 1 to 3 An electrode 100 according to an embodiment of the present disclosure may include a current collector 110 made of a metallic material, a first active material layer 120 formed on a first surface 111 of the current collector 110, and a second active material layer 150 formed on a second surface 112 of the current collector 110 opposite to the first surface 111. The first active material layer 120 may include a first patterned portion 130 and a second patterned portion 140 alternately arranged in the longitudinal direction of the current collector 110. The second patterned portion 140 may contain an active material that expands significantly during charging compared to the active material included in the first patterned portion 130. The current collector 110 may be formed of a metal foil such as copper, copper alloys, nickel, and nickel alloys.

[0062] When lithium ions in the secondary battery are intercalated during charging, the first patterned portion 130 may include active material with minimal expansion per unit volume, and the second patterned portion 140 may include active material with significant expansion per unit volume. In some embodiments, the first patterned portion 130 may include graphite material (e.g., graphite material only), and the second patterned portion 140 may include silicon material. In other embodiments, the first patterned portion 130 may include graphite material, and the second patterned portion 140 may include both graphite and silicon materials. That is, the second patterned portion 140 may be formed of silicon material or a mixture of graphite and silicon materials.

[0063] Because silicon expands much more per unit volume than graphite during charging, the second patterned portion 140, which includes silicon, can expand much more than the first patterned portion 130 during charging. This can be compensated for by forming a second patterned portion 140 with a thickness T12 smaller than the thickness T11 of the first patterned portion 130 (e.g., measured from the first surface 111 of the current collector 110). That is, the thickness T12 of the second patterned portion 140 can be set based on the silicon content. In some embodiments, the thickness T12 of the second patterned portion 140 can be set such that the maximum thickness T12c of the second patterned portion 140 that expands during charging corresponds to (e.g., is equal to) the maximum thickness T11c of the first patterned portion 130 that expands during charging (e.g., the maximum thickness T12c during charging can extend to be flush with (or coplanar with) the maximum thickness T11c during charging). The expansion level can be measured according to the silicon content by analyzing data or various experimental data.

[0064] refer to Figure 2 The width W12 of the second pattern portion 140 may be smaller than the width W11 of the first pattern portion 130 (e.g., measured along a direction parallel to the first surface 111 of the current collector 110 and along the alternating arrangement direction of the first pattern portion 130 and the second pattern portion 140). In some embodiments, the width W12 of the second pattern portion 140 may be equal to or greater than the width W11 of the first pattern portion 130.

[0065] The active material layer may contain an active material and may further contain a binder and / or a conductive material. In some embodiments, the active material layer may contain 90 wt% to 99 wt% of an active material, 0.5 wt% to 5 wt% of a binder, and 0 wt% to 5 wt% of a conductive material.

[0066] Non-aqueous adhesives, aqueous adhesives, dry adhesives, or combinations thereof can be used as adhesives. When an aqueous adhesive is used as an adhesive, it may further include a cellulose compound capable of imparting viscosity.

[0067] Figure 4 This is a cross-sectional view illustrating an example of how a plurality of second patterned portions of an electrode according to an embodiment of the present disclosure gradually thicken in the longitudinal direction of the current collector.

[0068] refer to Figure 4 The first active material layer 120 may include a plurality of first pattern portions 130 and a plurality of second pattern portions 140, and the plurality of first pattern portions 130 and the plurality of second pattern portions 140 may be arranged alternately in the longitudinal direction of the current collector 110. The plurality of second pattern portions 140 may gradually thicken in the longitudinal direction of the current collector 110.

[0069] In some embodiments, the second patterned portion 140 may thicken in the direction from one end 110a to the other end 110b of the current collector 110. That is, the thickness T12a of the second patterned portion 140a near one end 110a of the current collector 110 may be the smallest among all the second patterned portions 140, and the thickness T12b of the second patterned portion 140b near the other end 110b of the current collector 110 may be the largest among all the second patterned portions 140.

[0070] In some embodiments, when the electrode is wound, the second active material layer 150 may be placed on the radially inner side, and the first active material layer 120 may be arranged on the radially outer side. One end 110a of the current collector 110 may correspond to the front end of the wound electrode, and the other end 110b of the current collector 110 may correspond to the rear end of the wound electrode.

[0071] When the active material layer expands during the charging of the secondary battery, compressive force can be applied to the second active material layer 150 located inside the radius of curvature of the wound electrode, and tension can be applied to the first active material layer 120 disposed outside its radius of curvature. Even when tension is applied to the first active material layer 120, which includes the much expanded second patterned portion 140, the length of the stretched portion can be compensated by the much expanded second patterned portion 140.

[0072] Since the radius of curvature of the rear end of the wound electrode (i.e., the other end 110b of the current collector 110) can be greater than that of the front end of the wound electrode (i.e., one end 110a of the current collector 110), a stronger tension can be applied to the rear end of the wound electrode (i.e., the other end 110b of the current collector 110). The second patterned portion 140 can thicken in the direction from the front end of the wound electrode (i.e., one end 110a of the current collector 110) to the rear end of the wound electrode (i.e., the other end 110b of the current collector 110). The content of active material with a higher expansion rate increases as the second patterned portion 140 thickens, thereby compensating for the length of the stretched portion.

[0073] Figure 5 This is a cross-sectional view illustrating an example of how the width of a plurality of second patterned portions of an electrode according to an embodiment of the present disclosure gradually increases in the longitudinal direction of the current collector.

[0074] Reference Figure 5The first active material layer 120 may include a plurality of first pattern portions 130 and a plurality of second pattern portions 140, and the plurality of first pattern portions 130 and the plurality of second pattern portions 140 may be arranged alternately in the longitudinal direction of the current collector 110. The width of the plurality of second pattern portions 140 may gradually increase in the longitudinal direction of the current collector 110.

[0075] In some embodiments, the width of the second patterned portion 140 may increase in the direction from one end 110a to the other end 110b of the current collector 110. That is, the width W12a of the second patterned portion 140a near one end 110a of the current collector 110 may be the smallest among all the second patterned portions 140, and the width W12b of the second patterned portion 140b near the other end 110b of the current collector 110 may be the largest among all the second patterned portions 140.

[0076] In some embodiments, when the electrode is wound, the second active material layer 150 may be placed on the radially inner side, and the first active material layer 120 may be arranged on the radially outer side. One end 110a of the current collector 110 may correspond to the front end of the wound electrode, and the other end 110b of the current collector 110 may correspond to the rear end of the wound electrode.

[0077] When the active material layer expands during the charging of the secondary battery, compressive force can be applied to the second active material layer 150 located inside the radius of curvature of the wound electrode, and tension can be applied to the first active material layer 120 disposed outside its radius of curvature. Even when tension is applied to the first active material layer 120, which includes the much expanded second patterned portion 140, the length of the stretched portion can be compensated by the much expanded second patterned portion 140.

[0078] Since the radius of curvature of the rear end of the wound electrode (i.e., the other end 110b of the current collector 110) can be greater than that of the front end of the wound electrode (i.e., one end 110a of the current collector 110), a stronger tension can be applied to the rear end of the wound electrode (i.e., the other end 110b of the current collector 110). The width of the second patterned portion 140 can increase in the direction from the front end of the wound electrode (i.e., one end 110a of the current collector 110) to the rear end of the wound electrode (i.e., the other end 110b of the current collector 110). The content of active material with a higher expansion rate increases with the increase of the width of the second patterned portion 140, thereby compensating for the length of the stretched portion.

[0079] Figure 6 This is a cross-sectional view used to illustrate an example of an electrode according to another embodiment of the present disclosure, and Figure 7 It is used to show Figure 6A cross-sectional view showing the dimensions of the patterned portion of the electrodes.

[0080] refer to Figure 6 and Figure 7 According to another embodiment of the present disclosure, the electrode 200 may include a current collector 210 made of a metallic material, a first active material layer 220 formed on a first surface 211 of the current collector 210, and a second active material layer 250 formed on a second surface 212 of the current collector 210 opposite to the first surface 211. The first patterned portion and the second patterned portion of the first active material layer 220 may respectively include a first sub-patterned portion 230 and a second sub-patterned portion 240 alternately arranged in the longitudinal direction of the current collector 210, and the first patterned portion and the second patterned portion of the second active material layer 250 may respectively include a third sub-patterned portion 260 and a fourth sub-patterned portion 270 alternately arranged in the longitudinal direction of the current collector 210.

[0081] The second sub-pattern portion 240 may contain an active material having a higher expansion rate during charging than the active material included in the first sub-pattern portion 230, and the fourth sub-pattern portion 270 may contain an active material having a higher expansion rate during charging than the active material included in the third sub-pattern portion 260. The current collector 210 may be formed of a metal foil such as copper, copper alloy, nickel, and nickel alloy.

[0082] In some embodiments, the first sub-pattern portion 230 and the third sub-pattern portion 260 may comprise graphite material, and the second sub-pattern portion 240 and the fourth sub-pattern portion 270 may comprise silicon material. In other embodiments, the first sub-pattern portion 230 and the third sub-pattern portion 260 may comprise graphite material (e.g., graphite material only), and the second sub-pattern portion 240 and the fourth sub-pattern portion 270 may comprise both graphite material and silicon material. That is, the second sub-pattern portion 240 and the fourth sub-pattern portion 270 may be formed of silicon material or a mixture of graphite material and silicon material. Therefore, the electrode 200 according to the second embodiment of the present disclosure may include pattern portions comprising silicon material on each of the first active material layer 220 and the second active material layer 250 formed on respective sides of the current collector 210.

[0083] In some embodiments, the thickness T22 of the second sub-pattern portion 240 may be less than the thickness T21 of the first sub-pattern portion 230. The width W22 of the second sub-pattern portion 240 may be less than the width W21 of the first sub-pattern portion 230. The thickness and width of the third sub-pattern portion 260 may be equal to the thickness T21 and width W21 of the first sub-pattern portion 230, and the thickness T23 and width W23 of the fourth sub-pattern portion 270 may be equal to the thickness T22 and width W22 of the second sub-pattern portion 240.

[0084] For example, refer to Figure 6 The second sub-pattern portion 240 of the first active material layer 220 may be located opposite to the fourth sub-pattern portion 270 of the second active material layer 250 (e.g., the second sub-pattern portion 240 and the fourth sub-pattern portion 270 may overlap each other). In another example, the first sub-pattern portion 230 may be located opposite to the fourth sub-pattern portion 270.

[0085] Figure 8 This is a cross-sectional view illustrating an example of how the thickness of the patterned portions formed on the respective sides of the current collector of the electrode differs according to another embodiment of this disclosure, and Figure 9 This is a cross-sectional view illustrating an example of how the widths of patterned portions formed on the respective sides of the current collector of the electrode differ according to another embodiment of this disclosure.

[0086] The size of the patterned portion of the first active material layer 220 may be different from the size of the patterned portion of the second active material layer 250.

[0087] In some embodiments, reference Figure 8 The thickness T22a of the second sub-pattern portion 240a of the first active material layer 220 can be greater than the thickness T23a of the fourth sub-pattern portion 270a of the second active material layer 250. In some embodiments, the opposite can also be true. The width of the second sub-pattern portion 240a can be equal to the width of the fourth sub-pattern portion 270a, and the size of the first sub-pattern portion 230 of the first active material layer 220 can be equal to the size of the third sub-pattern portion 260 of the second active material layer 250.

[0088] When the electrode is wound with these features, the second active material layer 250 can be disposed on the radially inner side, and the first active material layer 220 can be disposed on the radially outer side. That is, the thicker second sub-pattern portion 240a can be disposed on the radially outer side, and the thinner fourth sub-pattern portion 270a can be located on the radially inner side.

[0089] In some embodiments, reference Figure 9 The width W22b of the second sub-pattern portion 240b of the first active material layer 220 may be greater than the width W23b of the fourth sub-pattern portion 270b of the second active material layer 250. In some embodiments, the opposite may also be true. The thickness of the second sub-pattern portion 240b may be equal to the thickness of the fourth sub-pattern portion 270b, and the size of the first sub-pattern portion 230 of the first active material layer 220 may be equal to the size of the third sub-pattern portion 260 of the second active material layer 250.

[0090] When the electrode is wound with these features, the second active material layer 250 can be arranged on the radially inner side, and the first active material layer 220 can be placed on the radially outer side. That is, the wider second sub-pattern portion 240b can be disposed on the radially outer side, and the narrower fourth sub-pattern portion 270b can be located on the radially inner side.

[0091] In some embodiments, the thickness and width of the second sub-pattern portions 240a and 240b of the first active material layer 220 may be different from the thickness and width of the fourth sub-pattern portions 270a and 270b of the second active material layer 250.

[0092] Figure 10 This is a cross-sectional view illustrating an example of an electrode according to yet another embodiment of the present disclosure, and Figure 11 It is used to show Figure 10 A cross-sectional view showing the dimensions of the patterned portion of the electrodes.

[0093] refer to Figure 10 and Figure 11 According to another embodiment of the present disclosure, the electrode 300 may include a current collector 310 made of a metallic material, a first active material layer 320 formed on a first surface 311 of the current collector 310, and a second active material layer 350 formed on a second surface 312 of the current collector 310 opposite to the first surface 311. The first active material layer 320 may include a first patterned portion 330 and a second patterned portion 340 alternately arranged in the longitudinal direction of the current collector 310. The second patterned portion 340 may contain an active material that expands significantly during charging compared to the active material included in the first patterned portion 330. The current collector 310 may be formed of a metal foil such as copper, copper alloys, nickel, and nickel alloys.

[0094] In some embodiments, the first patterned portion 330 may comprise a graphite material, and the second patterned portion 340 may comprise a silicon material. In other embodiments, the first patterned portion 330 may comprise a graphite material, and the second patterned portion 340 may comprise both a graphite material and a silicon material. That is, the second patterned portion 340 may be formed of a silicon material or a mixture of a graphite material and a silicon material.

[0095] The second patterned portion 340 of the first active material layer 320 may include a first patterned layer 341 formed on the current collector 310 and a second patterned layer 342 formed on the first patterned layer 341 and including an active material having a high expansion rate during charging (e.g., the first patterned layer 341 and the second patterned layer 342 may be stacked on the first surface 311, with the first patterned layer 341 between the first surface 311 and the second patterned layer 342). In some embodiments, the first patterned layer 341 may contain graphite material, and the second patterned layer 342 may contain silicon material (e.g., the first patterned layer 341 may contain the same material as the first patterned portion 330). In other embodiments, the first patterned layer 341 may contain graphite material, and the second patterned layer 342 may contain both graphite material and silicon material. That is, the second patterned layer 342 may be formed of silicon material or a mixture of graphite material and silicon material.

[0096] The thickness of the second patterned portion 340 of the first active material layer 320 can be less than the thickness T31 of the first patterned portion 330. That is, the sum of the thickness T32 of the first patterned layer 341 and the thickness T33 of the second patterned layer 342 can be less than the thickness T31 of the first patterned portion 330.

[0097] The width W32 of the second pattern portion 340 may be smaller than the width W31 of the first pattern portion 330. In some embodiments, the width W32 of the second pattern portion 340 may be equal to or greater than the width W31 of the first pattern portion 330.

[0098] Figure 12 This is a cross-sectional view illustrating an example of how a plurality of second patterned portions of an electrode according to another embodiment of the present disclosure gradually thicken in the longitudinal direction of the current collector.

[0099] refer to Figure 12 The first active material layer 320 may include a plurality of first pattern portions 330 and a plurality of second pattern portions 340 that may be alternately arranged in the longitudinal direction of the current collector 310. The plurality of second pattern portions 340 may gradually thicken in the longitudinal direction of the current collector 310.

[0100] In some embodiments, the first patterned layer of the second patterned portion 340 may have a constant thickness, and the thickness of the second patterned layer may be increased. The second patterned layer may become thicker in the direction from one end 310a to the other end 310b of the current collector 310. That is, the thickness T33a of the second patterned layer 342a of the second patterned portion 340 near one end 310a of the current collector 310 may be the smallest among all the second patterned layers 342, and the thickness T33b of the second patterned layer 342b of the second patterned portion 340 near the other end 310b of the current collector 310 may be the largest among all the second patterned layers 342.

[0101] In some embodiments, when the electrode is wound, the second active material layer 350 may be disposed on the radially inner side, and the first active material layer 320 may be disposed on the radially outer side. One end 310a of the current collector 310 may correspond to the front end of the wound electrode, and the other end 310b of the current collector 310 may correspond to the rear end of the wound electrode.

[0102] When the active material layer expands during secondary battery charging under these characteristics, compressive force can be applied to the second active material layer 350 disposed on the inner side of the radius of curvature of the wound electrode, and tension can be applied to the first active material layer 320 disposed on the outer side of the radius of curvature. Even when tension is applied to the first active material layer 320, which includes the much expanded second patterned portion 340, the length of the stretched portion can be compensated by the much expanded second patterned portion 340.

[0103] Since the radius of curvature of the rear end of the wound electrode (i.e., the other end 310b of the current collector 310) can be greater than that of the front end of the wound electrode (i.e., one end 310a of the current collector 310), a stronger tension can be applied to the rear end of the wound electrode (i.e., the other end 310b of the current collector 310). The second patterned layer of the second patterned portion 340 can thicken in the direction from the front end of the wound electrode (i.e., one end 310a of the current collector 310) to the rear end of the wound electrode (i.e., the other end 310b of the current collector 310). The content of active material with a higher expansion rate increases as the second patterned layer of the second patterned portion 340 thickens, thereby compensating for the length of the stretched portion.

[0104] Figure 13 This is a cross-sectional view illustrating an example of how the width of a plurality of second patterned portions of an electrode according to yet another embodiment of the present disclosure gradually increases in the longitudinal direction of the current collector.

[0105] refer to Figure 13 The first active material layer 320 may include a plurality of first pattern portions 330 and a plurality of second pattern portions 340 arranged alternately in the longitudinal direction of the current collector 310. The width of the plurality of second pattern portions 340 may gradually increase in the longitudinal direction of the current collector 310.

[0106] In some embodiments, the width of the second patterned portion 340 may increase in the direction from one end 310a to the other end 310b of the current collector 310. That is, the width W32a of the second patterned portion near one end 310a of the current collector 310 may be the smallest, and the width W32b of the second patterned portion near the other end 310b of the current collector 310 may be the largest. Therefore, the width W32a of the second patterned layer 342a of the second patterned portion near one end 310a of the current collector 310 may be the smallest among all the second patterned layers 342, and the width W32b of the second patterned layer 342b of the second patterned portion near the other end 310b of the current collector 310 may be the largest among all the second patterned layers 342.

[0107] In some embodiments, when the electrode is wound, the second active material layer 350 may be placed on the radially inner side, and the first active material layer 320 may be arranged on the radially outer side. One end 310a of the current collector 310 may correspond to the front end of the wound electrode, and the other end 310b of the current collector 310 may correspond to the rear end of the wound electrode.

[0108] When the active material layer expands during the charging of the secondary battery, compressive force can be applied to the second active material layer 350 located inside the radius of curvature of the wound electrode, and tension can be applied to the first active material layer 320 disposed outside its radius of curvature. Even when tension is applied to the first active material layer 320, which includes the much expanded second patterned portion 340, the length of the stretched portion can be compensated by the much expanded second patterned portion 340.

[0109] Since the radius of curvature of the rear end of the wound electrode (i.e., the other end 310b of the current collector 310) can be greater than that of the front end of the wound electrode (i.e., one end 310a of the current collector 310), a stronger tension can be applied to the rear end of the wound electrode (i.e., the other end 310b of the current collector 310). The width of the second patterned portion 340 can increase in the direction from the front end of the wound electrode (i.e., one end 310a of the current collector 310) to the rear end of the wound electrode (i.e., the other end 310b of the current collector 310). The width of the second patterned layer can increase with the increase of the width of the second patterned portion 340, thereby increasing the content of active material with a higher expansion rate to compensate for the length of the stretched portion.

[0110] Figure 14 This is a cross-sectional view illustrating an example of an electrode according to another embodiment of the present disclosure, and Figure 15 It is used to show Figure 14 A cross-sectional view showing the dimensions of the patterned portion of the electrodes.

[0111] refer to Figure 14 and Figure 15 According to another embodiment of the present disclosure, the electrode 400 may include a current collector 410 made of a metallic material, a first active material layer 420 formed on a first surface 411 of the current collector 410, and a second active material layer 450 formed on a second surface 412 of the current collector 410 opposite to the first surface 411.

[0112] The first active material layer 420 may include a first sub-pattern portion 430 and a second sub-pattern portion 440 alternately arranged in the longitudinal direction of the current collector 410, and the second active material layer 450 may include a third sub-pattern portion 460 and a fourth sub-pattern portion 470 alternately arranged in the longitudinal direction of the current collector 410.

[0113] The second sub-pattern portion 440 may contain an active material having a higher expansion rate during charging than the active material included in the first sub-pattern portion 430, and the fourth sub-pattern portion 470 may contain an active material having a higher expansion rate during charging than the active material included in the third sub-pattern portion 460. The current collector 410 may be formed of a metal foil such as copper, copper alloy, nickel, and nickel alloy.

[0114] In some embodiments, the first sub-pattern portion 430 and the third sub-pattern portion 460 may comprise graphite material, and the second sub-pattern portion 440 and the fourth sub-pattern portion 470 may comprise silicon material. In other embodiments, the first sub-pattern portion 430 and the third sub-pattern portion 460 may comprise graphite material, and the second sub-pattern portion 440 and the fourth sub-pattern portion 470 may comprise both graphite material and silicon material. That is, the second sub-pattern portion 440 and the fourth sub-pattern portion 470 may be formed of silicon material or a mixture of graphite material and silicon material. Therefore, the electrode 400 according to another embodiment of the present disclosure may include pattern portions comprising silicon material on each of the first active material layer 420 and the second active material layer 450 formed on respective sides of the current collector 410.

[0115] The second sub-pattern portion 440 of the first active material layer 420 may include a first patterned layer 441 formed on the current collector 410 and a second patterned layer 442 formed on the first patterned layer 441 and including active material that expands significantly during charging. In some embodiments, the first patterned layer 441 may include a graphite material, and the second patterned layer 442 may include a silicon material. In other embodiments, the first patterned layer 441 may include a graphite material, and the second patterned layer 442 may include both a graphite material and a silicon material. That is, the second patterned layer 442 may be formed of a silicon material or a mixture of a graphite material and a silicon material.

[0116] The fourth sub-pattern portion 470 of the second active material layer 450 may include a third patterned layer 471 formed on the current collector 410 and a fourth patterned layer 472 formed on the third patterned layer 471 and including active material that expands significantly during charging. In some embodiments, the third patterned layer 471 may include a graphite material, and the fourth patterned layer 472 may include a silicon material. In other embodiments, the third patterned layer 471 may include a graphite material, and the fourth patterned layer 472 may include both a graphite material and a silicon material. That is, the fourth patterned layer 472 may be formed of a silicon material or a mixture of a graphite material and a silicon material.

[0117] The thickness of the second sub-pattern portion 440 of the first active material layer 420 can be less than the thickness T41 of the first sub-pattern portion 430. That is, the sum of the thickness T42 of the first pattern layer 441 and the thickness T43 of the second pattern layer 442 can be less than the thickness T41 of the first sub-pattern portion 430.

[0118] The width W42 of the second sub-pattern portion 440 may be smaller than the width W41 of the first sub-pattern portion 430. In some embodiments, the width W42 of the second sub-pattern portion 440 may be equal to or greater than the width W41 of the first sub-pattern portion 430.

[0119] Furthermore, the thickness and width of the third sub-pattern portion 460 may be equal to the thickness T41 and width W41 of the first sub-pattern portion 430, and the thickness and width W43 of the fourth sub-pattern portion 470 may be equal to the thickness and width W42 of the second sub-pattern portion 440. In some embodiments, the thickness T42 of the first pattern layer 441 may be equal to the thickness T44 of the third pattern layer 471, and the thickness T43 of the second pattern layer 442 may be equal to the thickness T45 of the fourth pattern layer 472.

[0120] For example, refer to Figure 14 The second sub-pattern portion 440 of the first active material layer 420 may be located opposite to the fourth sub-pattern portion 470 of the second active material layer 450. In another example, the first sub-pattern portion 430 may be located opposite to the fourth sub-pattern portion 470.

[0121] Figure 16 and Figure 17 This is a cross-sectional view illustrating an example of how the thickness of the patterned portions formed on the respective sides of the current collector of the electrode differs according to another embodiment of this disclosure, and Figure 18 This is a cross-sectional view illustrating an example of how the widths of patterned portions formed on the respective sides of the current collector of the electrode differ according to another embodiment of the present disclosure.

[0122] The size of the patterned portion of the first active material layer 420 may be different from the size of the patterned portion of the second active material layer 450.

[0123] refer to Figure 16 The second sub-pattern portion 440a of the first active material layer 420 may be thicker than the fourth sub-pattern portion 470a of the second active material layer 450. In some embodiments, the thickness T42a of the first pattern layer 441a of the second sub-pattern portion 440a may be equal to the thickness T44a of the third pattern layer 471a of the fourth sub-pattern portion 470a, and the thickness T43a of the second pattern layer 442a of the second sub-pattern portion 440a may be greater than the thickness T45a of the fourth pattern layer 472a of the fourth sub-pattern portion 470a.

[0124] The width of the second sub-pattern portion 440a can be equal to the width of the fourth sub-pattern portion 470a, and the size of the first sub-pattern portion 430 of the first active material layer 420 can be equal to the size of the third sub-pattern portion 460 of the second active material layer 450.

[0125] When the electrode is wound with these features, the second active material layer 450 can be disposed on the radially inner side, and the first active material layer 420 can be disposed on the radially outer side. That is, the thicker second sub-pattern portion 440a can be disposed on the radially outer side, and the thinner fourth sub-pattern portion 470a can be located on the radially inner side.

[0126] In some embodiments, reference Figure 17 The second sub-pattern portion 440b of the first active material layer 420 may be thicker than the fourth sub-pattern portion 470b of the second active material layer 450. In some embodiments, the thickness T42b of the first pattern layer 441b of the second sub-pattern portion 440b may be greater than the thickness T44b of the third pattern layer 471b of the fourth sub-pattern portion 470b, and the thickness T43b of the second pattern layer 442b of the second sub-pattern portion 440b may be equal to the thickness T45b of the fourth pattern layer 472b of the fourth sub-pattern portion 470b.

[0127] The width of the second sub-pattern portion 440b can be equal to the width of the fourth sub-pattern portion 470b, and the size of the first sub-pattern portion 430 of the first active material layer 420 can be equal to the size of the third sub-pattern portion 460 of the second active material layer 450.

[0128] When the electrode is wound with these features, the second active material layer 450 can be disposed on the radially inner side, and the first active material layer 420 can be disposed on the radially outer side. That is, the thicker second sub-pattern portion 440b can be disposed on the radially outer side, and the thinner fourth sub-pattern portion 470b can be located on the radially inner side.

[0129] In some embodiments, reference Figure 18 The width W42c of the second sub-pattern portion 440c of the first active material layer 420 can be greater than the width W43c of the fourth sub-pattern portion 470c of the second active material layer 450. That is, the width W42c of the second pattern layer 442c of the second sub-pattern portion 440c can be greater than the width W43c of the fourth pattern layer 472c of the fourth sub-pattern portion 470c. The thickness of the second sub-pattern portion 440c can be equal to the thickness of the fourth sub-pattern portion 470c, and the size of the first sub-pattern portion 430 of the first active material layer 420 can be equal to the size of the third sub-pattern portion 460 of the second active material layer 450.

[0130] When the electrode is wound with these features, the second active material layer 450 can be disposed on the radially inner side, and the first active material layer 420 can be disposed on the radially outer side. That is, the wider second sub-pattern portion 440c can be disposed on the radially outer side of the wound electrode, and the narrower fourth sub-pattern portion 470c can be located on the radially inner side of the wound electrode.

[0131] Figure 19 This is a cross-sectional view illustrating an example of an electrode according to yet another embodiment of the present disclosure.

[0132] refer to Figure 19 According to another embodiment of the present disclosure, the electrode 500 may include a current collector 510 made of a metallic material, a first active material layer 520 formed on a first surface 511 of the current collector 510, and a second active material layer 550 formed on a second surface 512 of the current collector 510 opposite to the first surface 511.

[0133] The first active material layer 520 may include a first sub-pattern portion 530 and a second sub-pattern portion 540 alternately arranged in the longitudinal direction of the current collector 510, and the second active material layer 550 may include a third sub-pattern portion 560 and a fourth sub-pattern portion 570 alternately arranged in the longitudinal direction of the current collector 510.

[0134] The second sub-pattern portion 540 may include an active material having a higher expansion rate during charging than the active material included in the first sub-pattern portion 530, and the fourth sub-pattern portion 570 may include an active material having a higher expansion rate during charging than the active material included in the third sub-pattern portion 560. The current collector 510 may be formed of a metal foil such as copper, copper alloys, nickel, and nickel alloys.

[0135] In some embodiments, the first sub-pattern portion 530 and the third sub-pattern portion 560 may include graphite material, and the second sub-pattern portion 540 and the fourth sub-pattern portion 570 may include silicon material. In other embodiments, the first sub-pattern portion 530 and the third sub-pattern portion 560 may include graphite material, and the second sub-pattern portion 540 and the fourth sub-pattern portion 570 may include both graphite material and silicon material. In some embodiments, the second sub-pattern portion 540 and the fourth sub-pattern portion 570 may be formed of silicon material or a mixture of graphite material and silicon material.

[0136] The second sub-pattern portion 540 of the first active material layer 520 may be formed as a monolayer of silicon material or a mixture of graphite and silicon material. The fourth sub-pattern portion 570 of the second active material layer 550 may include a first patterned layer 571 formed on the current collector 510 and a second patterned layer 572 formed on the first patterned layer 571 and including an active material having a high expansion rate during charging. In some embodiments, the first patterned layer 571 may include graphite material, and the second patterned layer 572 may include silicon material. In other embodiments, the first patterned layer 571 may include graphite material, and the second patterned layer 572 may include both graphite and silicon material. That is, the second patterned layer 572 may be formed of silicon material or a mixture of graphite and silicon material.

[0137] The thickness T52 of the second sub-pattern portion 540 of the first active material layer 520 may be less than the thickness T51 of the first sub-pattern portion 530. The width W52 of the second sub-pattern portion 540 may be less than the width W51 of the first sub-pattern portion 530. In some embodiments, the width W52 of the second sub-pattern portion 540 may be equal to or greater than the width W51 of the first sub-pattern portion 530.

[0138] The thickness and width of the third sub-pattern portion 560 can be equal to the thickness T51 and width W51 of the first sub-pattern portion 530, and the thickness and width W53 of the fourth sub-pattern portion 570 can be equal to the thickness T52 and width W52 of the second sub-pattern portion 540. That is, the sum of the thickness T53 of the first pattern layer 571 and the thickness T54 of the second pattern layer 572 of the fourth sub-pattern portion 570 can be equal to the thickness T52 of the second sub-pattern portion 540. In some embodiments, the thickness T52 of the second sub-pattern portion 540 can be different from the thickness of the fourth sub-pattern portion 570.

[0139] For example, refer to Figure 19The second sub-pattern portion 540 of the first active material layer 520 may be arranged at a position opposite (e.g., overlapping) to the position of the fourth sub-pattern portion 570 of the second active material layer 550. In another example, the first sub-pattern portion 530 and the fourth sub-pattern portion 570 may be formed at opposite (e.g., overlapping) positions.

[0140] Figure 20 This is a cross-sectional view illustrating an example of an electrode according to another embodiment of the present disclosure.

[0141] refer to Figure 20 According to a sixth embodiment of this disclosure, the electrode 600 may include a current collector 610 made of a metallic material, a first active material layer 620 formed on a first surface 611 of the current collector 610, and a second active material layer 650 formed on a second surface 612 of the current collector 610 opposite to the first surface 611. The first active material layer 620 may include a first patterned portion 630 and a second patterned portion 640 alternately arranged in the longitudinal direction of the current collector 610. The second patterned portion 640 may contain an active material that expands significantly during charging compared to the active material included in the first patterned portion 630. The current collector 610 may be formed from a metal foil such as copper, copper alloys, nickel, and nickel alloys.

[0142] In some embodiments, the first patterned portion 630 may include a graphite material, and the second patterned portion 640 may include a silicon material. In other embodiments, the first patterned portion 630 may include a graphite material, and the second patterned portion 640 may include both a graphite material and a silicon material. That is, the second patterned portion 640 may be formed of a silicon material or a mixture of a graphite material and a silicon material.

[0143] The first patterned portion 630 may be formed in a wave-like shape in the longitudinal direction of the current collector 610. That is, the first patterned portion 630 may include alternately arranged thick ridge regions 631 (e.g., wavy portions convex away from the current collector 610) and thin valley regions 632 (e.g., recessed portions between two ridge regions 631). A second patterned portion 640 may be formed in the valley regions 632 of the first patterned portion 630. The second patterned portion 640 may be thinner than the ridge regions 631 of the first patterned portion 630. The height at the top of the second patterned portion 640 may be less than the height at the top of the ridge regions 631 of the first patterned portion 630 (e.g., relative to the first surface 611 of the current collector 610).

[0144] Figure 21 This is a cross-sectional view illustrating an example of an electrode according to another embodiment of the present disclosure.

[0145] refer to Figure 21According to another embodiment of the present disclosure, the electrode 700 may include a current collector 710 made of a metallic material, a first active material layer 720 formed on a first surface 711 of the current collector 710, and a second active material layer 750 formed on a second surface 712 of the current collector 710 opposite to the first surface 711. The first patterned portion and the second patterned portion of the first active material layer 720 may respectively include a first sub-patterned portion 730 and a second sub-patterned portion 740 alternately arranged in the longitudinal direction of the current collector 710, and the first patterned portion and the second patterned portion of the second active material layer 750 may respectively include a third sub-patterned portion 760 and a fourth sub-patterned portion 770 alternately arranged in the longitudinal direction of the current collector 710.

[0146] The second sub-pattern portion 740 may contain active material that expands more significantly during charging than the active material included in the first sub-pattern portion 730, and the fourth sub-pattern portion 770 may contain active material that expands more significantly during charging than the active material included in the third sub-pattern portion 760. The current collector 710 may be formed of a metal foil such as copper, copper alloy, nickel, or nickel alloy.

[0147] In some embodiments, the first sub-pattern portion 730 and the third sub-pattern portion 760 may comprise graphite material, and the second sub-pattern portion 740 and the fourth sub-pattern portion 770 may comprise silicon material. In other embodiments, the first sub-pattern portion 730 and the third sub-pattern portion 760 may comprise graphite material, and the second sub-pattern portion 740 and the fourth sub-pattern portion 770 may comprise both graphite material and silicon material. That is, the second sub-pattern portion 740 and the fourth sub-pattern portion 770 may be formed of silicon material or a mixture of graphite material and silicon material.

[0148] The first sub-pattern portion 730 of the first active material layer 720 can be formed in a wave-like shape in the longitudinal direction of the current collector 710. That is, the first sub-pattern portion 730 may include alternating thick ridge regions 731 and thin valley regions 732. A second sub-pattern portion 740 can be formed in the valley regions 732 of the first sub-pattern portion 730. The second sub-pattern portion 740 may be thinner than the ridge regions 731 of the first sub-pattern portion 730. The height at the top of the second sub-pattern portion 740 may be less than the height at the top of the ridge regions 731 of the first sub-pattern portion 730 (e.g., relative to the first surface 711 of the current collector 710).

[0149] The third sub-pattern portion 760 of the second active material layer 750 can be formed in a wave-like shape in the longitudinal direction of the current collector 710. That is, the third sub-pattern portion 760 may include alternating thick ridge regions 761 and thin valley regions 762. A fourth sub-pattern portion 770 may be formed in the valley regions 762 of the third sub-pattern portion 760. The fourth sub-pattern portion 770 may be thinner than the ridge regions 761 of the third sub-pattern portion 760. The height of the top of the fourth sub-pattern portion 770 may be less than the height of the top of the ridge regions 761 of the third sub-pattern portion 760 (e.g., relative to the second surface 712 of the current collector 710).

[0150] The ridge region 731 of the first subpattern portion 730 of the first active material layer 720 may face the valley region 762 of the third subpattern portion 760 of the second active material layer 750.

[0151] Figure 22 This is a cross-sectional view used to illustrate an example of a secondary battery according to some embodiments of the present disclosure.

[0152] refer to Figure 22 According to some embodiments of the present disclosure, the secondary battery 10 may include an electrode assembly 30 (including a first electrode 31, a separator 33 and a second electrode 32), a housing 20 that houses the electrode assembly 30 and is electrically connected to the second electrode 32, and a cover assembly 40 that closes the opening of the housing 20 and is electrically connected to the first electrode 31.

[0153] The electrode assembly 30 may include a diaphragm 33 and a first electrode 31 and a second electrode 32 positioned therebetween, and may be wound into an electrode core shape.

[0154] The first electrode 31 includes a first substrate and a first active material layer on the first substrate. The first electrode tab 31a can extend outward from a first uncoated portion of the first active material layer that is not positioned on the first substrate, and the first electrode tab 31a can be electrically connected to the cover assembly 40.

[0155] The second electrode 32 includes a second substrate and a second active material layer on the second substrate. A second electrode tab 32a can extend outward from a second uncoated portion of the unpositioned second active material layer on the second substrate, and the second electrode tab 32a can be electrically connected to the housing 20. The first electrode tab 31a and the second electrode tab 32a can extend in opposite directions.

[0156] The first electrode 31 can be used 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 32 can be used 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.

[0157] The separator 33 prevents short circuits between the first electrode 31 and the second electrode 32 while allowing lithium ions to move between them. The separator 33 can be made of, for example, a polyethylene membrane, a polypropylene membrane, or a polyethylene-polypropylene membrane.

[0158] The housing 20 houses the electrode assembly 30 and, together with the cover assembly 40, forms the appearance of the secondary battery 10. The housing 20 may have a generally cylindrical body portion and a bottom portion connected to one side (e.g., one end) of the body portion. The housing 20 may be made of a metal such as aluminum, aluminum alloy, or nickel-plated steel.

[0159] The second electrode connector 32a can be attached to the bottom of the housing 20 for electrical connection. One end of the first electrode connector 31a can be attached to the protrusion 42a of the terminal plate 42. The insulating tape 31b can be attached to the portion of the first electrode connector 31a other than the portion attached to the protrusion 42a of the terminal plate 42. Since the first electrode connector 31a, which is bent at the top of the electrode assembly 30, may come into contact with the cover plate 41 of the cover assembly 40 or the inner surface of the housing 20, causing a short circuit, the insulating tape 31b can be attached to the first electrode connector 31a.

[0160] In some embodiments, the second electrode 32 may include a current collector, a first active material layer formed on a first surface of the current collector, and a second active material layer formed on a second surface of the current collector opposite to the first surface; at least one of the first and second active material layers may include a first patterned portion and a second patterned portion alternately arranged in the longitudinal direction of the current collector; the second patterned portion may include an active material that expands more than the active material included in the first patterned portion during charging; and the second patterned portion may be thinner than the first patterned portion. The second electrode 32 may be formed according to reference respectively. Figures 1 to 21 The embodiments described herein are any of electrodes 100-700, and therefore will not be described again. The first electrode 31 may also be formed according to reference [reference needed]. Figures 1 to 21 Any of the electrodes 100 to 700 in the described embodiments.

[0161] The cover assembly 40 may include a cover plate 41 having a through hole 41a, a terminal plate 42 disposed on the cover plate 41 and including a protrusion 42a inserted into the through hole 41a, an upper insulator 43 disposed between the cover plate 41 and the terminal plate 42, and a lower insulator 44 located between the cover plate 41 and the electrode assembly 30.

[0162] The cover plate 41 can be formed in the shape of a disc with a through hole 41a at the center. The cover plate 41 can have a diameter larger than that of the terminal plate 42 and the upper insulator 43. The cover plate 41 can be welded to the upper end of the housing 20 to close the open side of the housing 20. In some embodiments, the shape of the cover plate 41 can vary depending on the shape of the housing 20 to which the cover plate 41 is fastened.

[0163] The terminal plate 42 can be formed into a circular shape with a diameter smaller than that of the cover plate 41, and a protrusion 42a that inserts into the through hole 41a of the cover plate 41 can be formed at the center of the terminal plate 42. The protrusion 42a of the terminal plate 42 can protrude toward the electrode assembly 30 while being inserted into the through hole 41a. The first electrode connector 31a can be connected to the protrusion 42a of the terminal plate 42. The shape of the terminal plate 42 can vary according to the shape of the cover plate 41.

[0164] The first electrode connector 31a can be connected to the protruding portion 42a of the terminal plate 42, while the second electrode connector 32a can be connected to the housing 20, so that the terminal plate 42 can be used as a positive electrode and the housing 20 can be used as a negative electrode.

[0165] The upper insulator 43 can be placed between the cover plate 41 and the terminal plate 42, so that the cover plate 41 and the terminal plate 42 can be electrically insulated. The cover plate 41 and the terminal plate 42 can be made of conductive metal material and can be electrically connected to the negative electrode of the second electrode terminal 32a and the positive electrode of the first electrode terminal 31a, respectively. Thus, the upper insulator 43 can insulate the cover plate 41 and the terminal plate 42 to prevent short circuits. The upper insulator 43 can be made of resin such as polypropylene and polyethylene.

[0166] The upper insulator 43 can be formed in a disc shape with an insertion hole 43a at the center, like the cover plate 41. As a result, the protrusion 42a of the terminal plate 42 can pass through the insertion hole 43a of the upper insulator 43 and the through hole 41a of the cover plate 41 to be placed inside the housing 20. The first electrode tab 31a can be connected to the protrusion 42a of the terminal plate 42 located inside the housing 20. The outer diameter of the upper insulator 43 can be equal to or similar to the outer diameter of the terminal plate 42. The outer diameter of the cover plate 41 can be larger than the outer diameters of the upper insulator 43 and the terminal plate 42. The diameter of the insertion hole 43a of the upper insulator 43 can be equal to or similar to the diameter of the through hole 41a of the cover plate 41.

[0167] The upper insulator 43 can heat and pressurize the cover plate 41 and the terminal plate 42 between the cover plate 41 and the terminal plate 42 to be heat-fused to the cover plate 41 and the terminal plate 42.

[0168] An insulating sheet 34 may be disposed between the cover assembly 40 and the electrode assembly 30 to insulate the upper portion of the electrode assembly 30 from the first electrode terminal piece 31a. The insulating sheet 34 may be placed on the upper portion of the electrode assembly 30. The diameter of the insulating sheet 34 may be smaller than the outer diameter of the electrode assembly 30. The insulating sheet 34 may be made of a resin such as polypropylene or polyethylene.

[0169] The lower insulator 44 can be formed in a disc shape with an insertion hole 44a at the center, like the cover plate 41. As a result, the protrusion 42a of the terminal plate 42 can pass through the insertion hole 44a of the lower insulator 44 and the through hole 41a of the cover plate 41 to be placed inside the housing 20. The outer diameter of the lower insulator 44 can be equal to or similar to the outer diameter of the electrode assembly 30. The outer diameter of the lower insulator 44 can be smaller than the outer diameter of the cover plate 41. The size of the insertion hole 44a of the lower insulator 44 can be formed to prevent the cover plate 41 from being exposed to the first electrode tab 31a. The diameter of the insertion hole 44a of the lower insulator 44 can be smaller than or equal to the diameter of the through hole 41a of the cover plate 41.

[0170] In some embodiments, the lower insulator 44 may be formed of an insulating tape and attached to the bottom surface of the cover plate 41, or it may be formed of an insulating sheet and attached to the bottom surface of the cover plate 41 by heat fusion.

[0171] refer to Figure 22 The described secondary battery 10 can be a coin-type or button-type battery. This disclosure can also be applied to other types of secondary batteries, such as cylindrical batteries. Figure 22 In this configuration, the first electrode connector 31a protrudes upward and connects to the cover assembly 40, while the second electrode connector 32a protrudes downward and connects to the housing 20. However, both the first electrode connector 31a and the second electrode connector 32a may protrude upward and connect to the cover assembly 40 and the housing 20, respectively.

[0172] Through summarization and review, it has been proposed to add silicon to the active material layer to increase the capacity of secondary batteries. However, silicon may have a high expansion rate during charging and discharging, which could damage the electrode plates.

[0173] In contrast, this disclosure provides an electrode and a secondary battery including the electrode, wherein the active material layer of the electrode can be formed to include a first patterned portion without silicon material and a second patterned portion having silicon material, and the second patterned portion can be formed to be thinner than the first patterned portion, thereby preventing the electrode from over-expanding during charging and discharging of the secondary battery.

[0174] According to some embodiments of this disclosure, the active material layer of the negative electrode, which has a high expansion rate during the charging and discharging of the secondary battery, can be formed to include a first patterned portion without silicon material and a second patterned portion with silicon material, and the second patterned portion can be formed to be thinner than the first patterned portion, so that the negative electrode expands less during the charging and discharging of the secondary battery.

[0175] However, the aspects and features of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the above detailed description other aspects and features not mentioned.

[0176] While this disclosure has been described with reference to embodiments and accompanying drawings illustrating aspects thereof, it is not limited thereto. Various modifications and variations can be made by those skilled in the art within the spirit and scope of this disclosure, the claims, and their equivalents.

[0177] Example embodiments have been disclosed herein. While specific terminology is used, they are used and interpreted in a general and descriptive sense only and not for limiting purposes. In some cases, as will be apparent to those skilled in the art at the time of filing this application, unless otherwise specifically stated, 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. Therefore, 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 appended claims.

Claims

1. An electrode, comprising: current collector; A first active material layer is on the first surface of the current collector; as well as A second active material layer is formed on the second surface of the current collector, the second surface being opposite to the first surface. At least one of the first active material layer and the second active material layer includes a first pattern portion and a second pattern portion alternately arranged in the longitudinal direction of the current collector. The second patterned portion includes an active material having a higher expansion rate during charging than the active material in the first patterned portion, and The second pattern portion is thinner than the first pattern portion.

2. The electrode according to claim 1, wherein the first patterned portion comprises graphite material.

3. The electrode of claim 1, wherein the second patterned portion comprises silicon material.

4. The electrode according to claim 1, wherein the second patterned portion comprises graphite material and silicon material.

5. The electrode according to claim 3 or 4, wherein the thickness of the second patterned portion is set based on the content of the silicon material.

6. The electrode of claim 1, wherein the maximum thickness of the second patterned portion during charging is flush with the maximum thickness of the first patterned portion during charging.

7. The electrode according to claim 1, wherein the second patterned portion comprises a plurality of second patterned portions, the thickness of the plurality of second patterned portions gradually increasing in the longitudinal direction of the current collector.

8. The electrode according to claim 1, wherein the second pattern portion comprises a plurality of second pattern portions, the width of the plurality of second pattern portions gradually increasing in the longitudinal direction of the current collector.

9. The electrode according to claim 1, wherein: The first patterned portion and the second patterned portion of the first active material layer respectively include a first sub-patterned portion and a second sub-patterned portion alternately arranged in the longitudinal direction of the current collector, and The first patterned portion and the second patterned portion of the second active material layer respectively include a third sub-patterned portion and a fourth sub-patterned portion arranged alternately in the longitudinal direction of the current collector.

10. The electrode of claim 9, wherein the second sub-pattern portion is thicker than the fourth sub-pattern portion.

11. The electrode according to claim 9, wherein the width of the second sub-pattern portion is greater than the width of the fourth sub-pattern portion.

12. The electrode of claim 9, wherein the second patterned portion comprises: A first patterned layer is applied to the current collector; as well as A second patterned layer is placed on the first patterned layer and includes an active material having a predetermined expansion rate during charging.

13. The electrode of claim 12, wherein the first patterned layer comprises a graphite material, and the second patterned layer comprises a silicon material.

14. The electrode of claim 12, wherein the first patterned layer comprises a graphite material, and the second patterned layer comprises a graphite material and a silicon material.

15. The electrode according to claim 9, wherein: The second sub-pattern portion includes: A first patterned layer is formed on the first surface of the current collector; and A second patterned layer, on the first patterned layer and including an active material having a predetermined expansion rate during charging, and The fourth sub-pattern portion includes: A third patterned layer is formed on the second surface of the current collector; and A fourth patterned layer, on the third patterned layer, includes an active material having a predetermined expansion rate during charging.

16. The electrode of claim 15, wherein the first patterned layer and the third patterned layer have the same thickness, and the second patterned layer is thicker than the fourth patterned layer.

17. The electrode of claim 15, wherein the second patterned layer and the fourth patterned layer have the same thickness, and the first patterned layer is thicker than the third patterned layer.

18. The electrode of claim 1, wherein the first patterned portion has a waveform in the longitudinal direction of the current collector, and the second patterned portion is in the valley region of the first patterned portion.

19. The electrode according to claim 1, wherein: The first patterned portion and the second patterned portion of the first active material layer respectively include a first sub-patterned portion that is wavy in the longitudinal direction of the current collector and a second sub-patterned portion in the valley region of the first sub-patterned portion. The first patterned portion and the second patterned portion of the second active material layer respectively include a third sub-patterned portion that is wavy in the longitudinal direction of the current collector and a fourth sub-patterned portion in the valley region of the third sub-patterned portion, and The ridge region of the first sub-pattern portion faces the valley region of the third sub-pattern portion.

20. A secondary battery, comprising: The electrode assembly includes a first electrode, a diaphragm, and a second electrode; A housing that houses the electrode assembly and is electrically connected to the second electrode; as well as A cover assembly that closes the opening of the housing and is electrically connected to the first electrode. At least one of the first electrode and the second electrode is an electrode according to any one of claims 1 to 19.

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