Electrode and secondary battery

Abstract

The present disclosure relates to an electrode and a secondary battery, and a technical problem to be solved is to provide an electrode that prevents a substrate from being damaged by a tab. For this purpose, the present disclosure provides an electrode comprising: a substrate; an active material layer provided on a portion of the substrate; and a tab in contact with the substrate, in which at least a portion of the tab is on the active material layer.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0159843, filed on November 12, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to electrodes and secondary batteries capable of preventing cracking in a substrate. Background Technology

[0004] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for electric motors in hybrid vehicles, electric vehicles, etc., and as storage batteries. These secondary batteries include electrode assemblies containing electrodes (e.g., containing positive and / or negative electrodes), a housing of the electrode assemblies, electrode terminals connected to the electrode assemblies, etc.

[0005] The electrode includes a substrate and an active material layer formed on the substrate. The active material layer includes an active material. Furthermore, the electrode may include a terminal attached to the substrate. Electrode assemblies including such electrodes may, for example, be wound to form an electrode core (i.e., multiple electrode layers are stacked and wound together to obtain a cylindrical wound structure).

[0006] When the secondary battery is charged, the electrodes may expand. In this case, as the electrodes are compressed due to expansion, the substrate may deform. In particular, the stress applied to the substrate may concentrate at the terminal block boundaries, which are the areas where the terminal blocks are attached to the substrate. Accordingly, the terminal block boundaries may reach their local elongation limits, and cracks may occur at the terminal block boundaries.

[0007] In recent years, with the increasing demand for high-capacity rechargeable batteries, substrates have tended to become thinner. Consequently, cracks are more likely to occur in the substrate.

[0008] When cracks occur in the electrodes, the resistance of the secondary battery increases, heat is generated around the cracks, and / or the capacity of the secondary battery decreases, which leads to a reduction in the reliability of the secondary battery.

[0009] The information disclosed above in the background section of this disclosure is intended only to enhance understanding of the background of this disclosure, and therefore may include information that does not constitute related technology. Summary of the Invention

[0010] One embodiment of this disclosure relates to an electrode and / or a secondary battery that mitigates cracking in a substrate.

[0011] One embodiment of this disclosure relates to electrodes and / or secondary batteries that relieve stress by having connecting tabs concentrated on a substrate.

[0012] However, the technical problems to be solved by this disclosure are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art through the following description.

[0013] According to one embodiment of the present disclosure, in order to solve the above-mentioned technical problem, the electrode includes: a substrate; an active material layer provided on a portion of the substrate; and a terminal piece in contact with the substrate, wherein at least a portion of the terminal piece is located on the active material layer.

[0014] According to one embodiment of this disclosure, in order to solve the above-mentioned technical problems, a secondary battery includes: an electrode assembly formed by winding an electrode and a separator; and a housing for housing the electrode assembly, wherein the electrode includes: a substrate; an active material layer provided on a portion of the substrate; and a terminal piece in contact with the substrate, wherein at least a portion of the terminal piece is located on the active material layer. Attached Figure Description

[0015] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the detailed description of the present disclosure below, are used to help further understand the technical concept of the present disclosure. Therefore, the present disclosure is not limited to the contents described in these drawings, wherein:

[0016] Figure 1 This is a schematic cross-sectional view of an example of a cylindrical secondary battery according to one embodiment of the present disclosure;

[0017] Figure 2 This is a cross-sectional view of an example of the illustrated electrode;

[0018] Figure 3 This is a cross-sectional view of an example of the illustrated electrode assembly;

[0019] Figure 4 This is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present disclosure;

[0020] Figure 5 This is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present disclosure;

[0021] Figure 6 This is a top view illustrating an example of an electrode according to one embodiment of the present disclosure;

[0022] Figure 7This is a cross-sectional view illustrating an example of the thickness of a connector according to one embodiment of the present disclosure;

[0023] Figure 8 This is a cross-sectional view illustrating an example of a reinforcing layer according to one embodiment of the present disclosure;

[0024] Figure 9 This is a top view illustrating an example of a welded portion according to one embodiment of the present disclosure;

[0025] Figure 10 This is a top view illustrating an example of a welded portion according to one embodiment of the present disclosure; and

[0026] Figure 11 This is a cross-sectional view illustrating an example of an insulating tape according to one embodiment of the present disclosure. Detailed Implementation

[0027] Preferred embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the specification and claims should not be construed as limited to their ordinary or dictionary meanings, but should be interpreted in a way consistent with the technical concepts of the present disclosure, based on the principle that the inventor can appropriately define the concepts of the terms in order to interpret his or her invention in the best manner. Accordingly, it should be understood that the configurations shown in the drawings and the embodiments described herein are merely preferred embodiments of the present disclosure and are not intended to represent all the technical ideas of the invention, and various equivalents and modifications may be substituted for them at the time of filing of this application.

[0028] Furthermore, when used herein, the term "comprising" and its variations specify the presence of a feature, number, step, operation, component, element, and / or group thereof, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, elements, and / or groups thereof.

[0029] Furthermore, to aid in understanding the invention, the accompanying drawings are not drawn to scale, and the dimensions of some components may be enlarged. Additionally, in different embodiments, the same reference numerals may be assigned to the same components.

[0030] When two things being compared are described as “same,” it means that they are “approximately the same.” Therefore, “approximately the same” can include what is considered a low deviation in the field, such as less than 5%. Furthermore, the uniformity of parameters in a given region can imply uniformity from an average perspective.

[0031] Although terms such as "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another, and unless otherwise specifically stated, it should be understood that the first component can also be the second component.

[0032] Throughout the instruction manual, unless otherwise specifically stated, each element may be singular or plural.

[0033] The arrangement of any component in the "upper part (or lower part)" or "above (or below)" of a component means that the component not only contacts the upper surface (or lower surface) of the component, but other components may be located between the component and any components disposed on (or below) the component.

[0034] Furthermore, when a component is described as being “connected,” “linked,” or “attached” to another component, it should be understood that the components may be directly connected or linked to each other, but other components may be “intermediate” between the components, or each component may be “connected,” “linked,” or “attached” to another component. Additionally, when a part is “electrically connected” to another part, this includes not only the case where it is “directly connected,” but also the case where it is “connected” through another component or element that is intermediate between them.

[0035] Unless otherwise stated, throughout the specification, whenever "A and / or B" is mentioned, it means A, B, or A and B. That is, "and / or" includes all or any combination of the listed items. When "C to D" is described, it means C and below, unless otherwise stated.

[0036] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure.

[0037] In this specification, the X-axis represents the width direction of the connector. The Y-axis represents the thickness direction of the connector. The Y-axis is perpendicular to the X-axis. The Z-axis represents the longitudinal direction of the connector. The Z-axis is perpendicular to each of the X and Y axes.

[0038] Figure 1 This is a schematic cross-sectional view of an example of a cylindrical secondary battery according to one embodiment of the present disclosure;

[0039] like Figure 1As shown, a cylindrical lithium-ion secondary battery 100 according to one embodiment of the present disclosure may include a cylindrical housing 50, an electrode assembly 40, and a cover assembly 60. Furthermore, in some cases, the cylindrical lithium-ion secondary battery 100 may further include a center pin (not shown). Additionally, in the secondary battery 100 according to the embodiment of the present disclosure, because the cover assembly 60 also performs a current interruption operation, the cover assembly 60 is also referred to in some cases as a current interruption device.

[0040] The cylindrical housing 50 may include a generally circular base portion and cylindrical sidewalls extending upwards from the circumference of the base portion for a certain length. During the manufacturing process of the secondary battery, the top portion of the cylindrical housing 50 is open. Therefore, during the assembly process of the secondary battery, the electrode assembly 40 and the center pin can be inserted into the cylindrical housing 50 along with the electrolyte. The cylindrical housing 50 may be made of, for example, but not limited to, steel, stainless steel, aluminum, aluminum alloys, or equivalents thereof.

[0041] Electrode assembly 40 can be housed inside cylindrical housing 50. Electrode assembly 40 may include: a negative electrode 20, in which a negative electrode current collector is coated with a negative electrode active material (e.g., graphite, carbon, etc.); a positive electrode 10, in which a positive electrode current collector is coated with a positive electrode active material (e.g., transition metal oxides (LiCoO2, LiNiO2, LiMn2O4, etc.)); and a separator 30, located between negative electrode 20 and positive electrode 10, to prevent short circuits and allow only lithium ion movement. Furthermore, negative electrode 20, positive electrode 10, and separator 30 may be wound into a generally cylindrical shape.

[0042] The cover assembly 60 includes an upper cover. The cover assembly 60 may further include at least one of a lower cover, a vent, and an insulator. This cover assembly 60 is coupled to an opening in the cylindrical housing 50 to seal the electrode assembly 40 inside the cylindrical housing 50.

[0043] However, the invention is not limited thereto, and the housing can have various shapes such as circular, bag-shaped, etc. Furthermore, the housing can be made of metals such as aluminum, aluminum alloys, and nickel-plated steel, or of a laminated film or plastic forming the bag.

[0044] As described above, the electrode assembly 40 includes a negative electrode 20, a positive electrode 10, and a diaphragm 30 located between the negative electrode 20 and the positive electrode 10. Furthermore, the electrode assembly 40, together with an electrolyte (not shown), is housed in a cylindrical casing 50. The electrode assembly 40 and the electrolyte will be described below.

[0045] Positive electrode 10

[0046] As the positive electrode active material, compounds capable of reversibly inserting and deintercalating lithium (e.g., lithiation intercalation compounds) can be used. Specifically, at least one of lithium and a composite oxide of a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0047] The composite oxide can be a lithium transition metal composite oxide, and specific examples may include lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate-based compounds, cobalt-free nickel manganese oxides, or combinations thereof.

[0048] For example, a compound represented by any of the following chemical formulas can be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b- c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, O≤e≤0.1); Li a NiG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G bO2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); and Li a FePO4 (0.90≤a≤1.8).

[0049] In the above chemical formulas, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L 1 It is Mn, Al, or a combination thereof.

[0050] The positive electrode 10 for the lithium secondary battery 100 may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0051] Based on a 100wt% positive electrode active material layer, the content of the positive electrode active material can be from 90wt% to 99wt%, and based on the 100wt% positive electrode active material layer, the content of each of the binder and the conductive material can be from 0.5wt% to 5wt%.

[0052] Al (foil) can be used as a current collector, but the present invention is not limited thereto.

[0053] negative electrode 20

[0054] Negative electrode active materials include materials capable of reversibly inserting / deintercalating lithium ions, lithium metal, lithium and metal alloys, materials capable of doping and dedoping lithium, or transition metal oxides.

[0055] Materials capable of reversibly inserting / deintercalating lithium ions can be carbon-based negative electrode active materials, and may include, for example, crystalline carbon, amorphous carbon, or combinations thereof. Examples of crystalline carbon may include graphite such as natural or artificial graphite, and examples of amorphous carbon may include soft carbon, hard carbon, mesophase pitch carbides, calcined coke, etc.

[0056] As a material capable of doping and de-doping lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite material, SiO x (0 < x ≤ 2, such as SiO2), a Si-based alloy, or a combination thereof.

[0057] The silicon-carbon composite material can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite material can be in the form of silicon particles coated with amorphous carbon on their surface.

[0058] The silicon-carbon composite material can further include crystalline carbon. For example, the silicon-carbon composite material can include a core including crystalline carbon and silicon particles, and an amorphous carbon active material layer located on the surface of the core.

[0059] The negative electrode 20 for the lithium secondary battery 100 includes a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer includes a negative electrode active material, and can further include a binder and / or a conductive material.

[0060] For example, the negative electrode active material layer can include 90 wt% to 99 wt% of the negative electrode active material, 0.5 wt% to 5 wt% of the binder, and 0 wt% to 5 wt% of the conductive material.

[0061] The binder can include a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity can be further included.

[0062] As the negative electrode current collector, any material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof can be used.

[0063] The electrolyte for the lithium secondary battery 100 includes a non-aqueous organic solvent and a lithium salt.

[0064] The non-aqueous organic solvent serves as a medium through which ions participating in the electrochemical reaction of the battery can move.

[0065] The non-aqueous organic solvent can be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and can be used alone or in a combination of two or more of them.

[0066] In addition, when a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate can be used in combination.

[0067] Diaphragm 30

[0068] Depending on the type of lithium secondary battery 100, the separator 30 may be present between the positive electrode 10 and the negative electrode 20. As the separator 30, a multilayer film of polyethylene, polypropylene, polyvinylidene fluoride, or two or more of these can be used.

[0069] The diaphragm 30 may include a porous substrate and an active material layer, the active material layer including organic materials, inorganic materials or combinations thereof, and located on one or both sides of the porous substrate.

[0070] Organic materials may include polyvinylidene fluoride polymers or (meth)acrylic acid polymers.

[0071] Inorganic materials may include, but are not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and combinations thereof.

[0072] Organic and inorganic materials can exist as a mixture in an active material layer, or they can exist as a stack of active material layers including organic materials and active material layers including inorganic materials.

[0073] Electrolyte (not shown)

[0074] The electrolyte used in the secondary battery 100 includes a non-aqueous organic solvent and a lithium salt.

[0075] Non-aqueous organic solvents act as a medium through which ions participating in the electrochemical reactions of the battery can move.

[0076] Non-aqueous organic solvents can be carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvents, aprotic solvents, or combinations thereof.

[0077] Examples of carbonate-based solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc.

[0078] Examples of ester-based solvents include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, methacryloxylactone, valproic acid lactone, caprolactone, etc.

[0079] Examples of ether-based solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran. Additionally, cyclohexanone and the like can be used as ketone-based solvents. Ethanol, isopropanol, and the like can be used as alcohol-based solvents, and nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include double bonds, aromatic rings, or ether groups); amides such as dimethylformamide; dioxolane such as 1,3-dioxolane and 1,4-dioxolane; and tetrahydrothiophene sulfone, etc., can be used as aprotic solvents.

[0080] Non-aqueous organic solvents can be used alone or in combination of two or more.

[0081] Furthermore, when using carbonate-based solvents, a mixture of cyclic carbonates and chain carbonates can be used, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio of 1:1 to 1:9.

[0082] Lithium salts are materials dissolved in organic solvents and act as a source of lithium ions within batteries, ensuring the basic operation of secondary batteries and facilitating the movement of lithium ions between the positive and negative electrodes. Representative examples of lithium salts may include one or more selected from the following: LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 Lithium trifluoromethanesulfonate (where x and y are integers from 1 to 20), lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalate)phosphate (LiDFOB), and lithium bis(oxalate)borate (LiBOB).

[0083] Figure 2 This is a cross-sectional view of an example of the illustrated electrode.

[0084] exist Figure 2 In the text, 200 represents an electrode according to one embodiment of the present disclosure.

[0085] Electrode 200 may include: substrate 210; active material layer 220 provided on a portion of substrate 210; and terminal piece 230 having one side in contact with a portion of substrate 210 and another side extending away from substrate 210.

[0086] The following section will describe each component of electrode 200 in detail.

[0087] The electrode assembly 40 may include a positive electrode 10 and / or a negative electrode 20. For example, as Figure 1 As described herein, an electrode assembly 40 according to one embodiment of the present disclosure includes a positive electrode 10 and a negative electrode 20. As illustrated, an electrode 200 according to one embodiment of the present disclosure can be used as the positive electrode 10 included in the electrode assembly 40. In this case, an electrode 200 according to one embodiment of the present disclosure can be used as the negative electrode 20 included in the electrode assembly 40. Furthermore, an electrode 200 according to one embodiment of the present disclosure can be used as both the positive electrode 10 and the negative electrode 20 included in the electrode assembly 40.

[0088] The substrate 210 may include the current collector described above. When the electrode 200 is the positive electrode 10, the substrate 210 includes a positive electrode current collector. The positive electrode current collector includes, for example, aluminum (Al). When the electrode 200 is the negative electrode 20, the substrate 210 includes a negative electrode current collector. The negative electrode current collector includes, for example, copper (Cu).

[0089] The active material layer 220 may include the active material layer described above. When electrode 200 is positive electrode 10, the active material includes positive electrode active material. When electrode 200 is negative electrode 20, the active material includes negative electrode active material. Furthermore, the active material layer 220 may further include a binder and / or a conductive material.

[0090] The active material layer 220 can be coated onto the substrate 210 in the form of a slurry containing the active material. In this way, the electrode 200 can form a wet electrode. Alternatively, the active material layer 220 can be attached to the substrate 210 in the form of a separate film containing the active material. In this way, the electrode 200 can form a dry electrode.

[0091] The active material layer 220 can be provided on a portion of the substrate 210. For example, the active material layer 220 can be provided on a portion of one surface of the substrate 210. Alternatively, for example, as Figure 2 As illustrated, the active material layer 220 can be provided on a portion of both surfaces of the substrate 210. In this case, the area on which the active material layer 220 is provided on a portion of the substrate 210 can be conveniently referred to as coated portion A. Furthermore, the area of ​​the substrate 210 that is not provided with the active material layer 220 and is exposed to the outside can be conveniently referred to as uncoated portion N.

[0092] One side of the connector 230 can be attached to the substrate 210. The other side of the connector 230 can be not attached to the substrate 210, but can extend outward from the substrate 210.

[0093] like Figure 2As illustrated, the terminal piece 230 may include an intermediate terminal piece, with active material layers 220 provided on both sides of the terminal piece 230. Alternatively, for example, with Figure 2 As shown in the diagram, the terminal block 230 can be attached to one end of the substrate 210. In this way, the terminal block 230 can include all types of terminal blocks having at least one side provided on the substrate 210.

[0094] The terminal block 230 provides a channel through which the external electrode 200 can be electrically connected. For this purpose, the terminal block 230 comprises a conductive material. For example, the terminal block 230 comprises a metallic material. When the electrode 200 is a positive electrode, the terminal block 230 may comprise aluminum or an aluminum alloy. When the electrode 200 is a negative electrode, the terminal block 230 may comprise nickel, nickel-plated steel, and / or alloys thereof. In this way, electrons can move along the terminal block 230 to the electrode 200 or from the electrode 200 to the external electrode.

[0095] The terminal block 230 can be bonded to the substrate 210. For example, the terminal block 230 can be attached to the substrate 210 via a conductive strip or adhesive material. Alternatively, when the terminal block 230 comprises a metallic material, the terminal block 230 can be bonded to the substrate 210 by welding. For example, the terminal block 230 can be bonded to the substrate 210 by various welding methods such as ultrasonic welding, laser welding, etc.

[0096] Figure 3 This is a cross-sectional view of an example of an electrode assembly.

[0097] Electrode 200 may include a tab 230. In this case, electrode 200 may repeatedly expand and contract as the secondary battery 100 performs charging and discharging or as the secondary battery 100 deteriorates. When this occurs, substrate 210 receives forces from the diaphragm and / or electrodes located in front of and behind substrate 210.

[0098] For example, electrode assembly 300 (e.g., including...) Figure 1 The electrode assembly 40 described herein includes a positive electrode 200P (e.g., including...). Figure 1 The positive electrode 10 and the negative electrode 200N (e.g., including the positive electrode 10) and negative electrode 200N described in the text. Figure 1 (The negative electrode 20 is described in the diagram). For ease of explanation, the diagram of the diaphragm 30 located between the positive electrode 200P and the negative electrode 200N is omitted. The positive electrode 200P and the negative electrode 200N can be wound together to form an electrode core.

[0099] The positive electrode 200P may include a positive electrode substrate 210P and a positive electrode terminal block 230P.

[0100] As the negative electrode 200N expands, the positive electrode contact 230P can receive force from the negative electrode 200N. The positive electrode contact 230P can apply stress to the positive electrode substrate 210P. In particular, the positive electrode substrate 210P can be more significantly compressed in the area that contacts the edge of the positive electrode contact 230P. Accordingly, cracks may occur in the positive electrode substrate 210P.

[0101] In this manner, the reliability of the secondary battery 100 may be reduced or safety issues may arise if a crack occurs in the substrate 210 or damage occurs in the electrode 200. Therefore, a solution to these problems is needed.

[0102] Figure 4 This is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present disclosure.

[0103] Figure 5 This is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present disclosure.

[0104] Figure 6 This is a top view schematically showing an example of an electrode according to one embodiment of the present disclosure.

[0105] An electrode 200 according to one embodiment of the present disclosure may include: a substrate 210; an active material layer 220 provided on a portion of the substrate 210; and a terminal piece 230 in contact with the substrate 210, wherein at least a portion of the terminal piece 230 is located on the active material layer 220. In the description of the electrode 200, terms related to... Figures 1 to 3 The same or similar content as described.

[0106] Figure 4 and Figure 5 An exemplary cross-sectional view of the connector 230 in the XY plane is shown, and Figure 6 An example top view of the connector 230 in the XZ plane is shown.

[0107] like Figure 4 and Figure 5 As shown, the terminal piece 230 is formed to be longer in the width direction (X-axis) than in the thickness direction (Y-axis).

[0108] like Figure 4 As illustrated, for example, the terminal block 230 can be formed with a constant thickness in its cross-section. For example, the terminal block 230 can be formed with a polygonal cross-section. For example, the terminal block 230 can be formed with a rectangular cross-section. In this way, the terminal block 230 can be stably bonded to the substrate 210 and / or manufactured with high process efficiency.

[0109] Alternatively, such as Figure 5As illustrated, for example, the terminal piece 230 can be formed with a shape having a non-uniform thickness in its cross-section. For example, the terminal piece 230 can be formed with a shape that is relatively thick at the center and relatively thin at the edges. For example, the terminal piece 230 can be formed with an elliptical cross-section, a shape where two curved surfaces intersect, etc. This allows the terminal piece 230 to be more easily bonded to the substrate 210, and / or further reduces the stress exerted on the substrate 210 and / or the active material layer 220 by the edges of the terminal piece 230.

[0110] like Figure 6 As shown in the figure, the terminal block 230 can be formed into a shape that is longer in the longitudinal direction (Z-axis) than in the width direction (X-axis).

[0111] In the longitudinal direction (Z-axis), the terminal block 230 is formed such that one side contacts the substrate 210, and the other side facing the first side extends away from the substrate 210.

[0112] exist Figure 4 and Figure 5 In the diagram, the terminal block 230 is depicted as spaced apart from the substrate 210, but as shown below Figure 9 and Figure 10 As described above, at least a portion of one side (e.g., the first side) of the terminal block 230 is in contact with the substrate 210.

[0113] For example, one side of the connector 230 can contact at least a portion of the uncoated portion N. In this way, the connector 230 can be electrically connected to the substrate 210, and the electrode 200 can be electrically connected to the outside through the connector 230.

[0114] The other side (e.g., the second side) of the terminal block 230 extends away from the substrate 210. Accordingly, the other side of the terminal block 230 is not located on the substrate 210. The other side of the terminal block 230 is electrically connected to, for example, the cover assembly 60, the current collector plate (not shown), the cylindrical housing 50, etc. In this way, the terminal block 230 allows the electrode 200 to be electrically connected to the outside.

[0115] like Figure 6 As illustrated, for example, the connector 230 may include a first edge 231 connecting one side of the connector 230 and the other side of the connector 230. The first edge 231 is the region of the connector 230 closest to the substrate 210 in the thickness direction (Y-axis) of the connector 230. Furthermore, the first edge 231 is the region of the connector 230 located at its edge in the width direction (X-axis).

[0116] The terminal block 230 may be formed such that at least a portion of the first edge 231 is located on the active material layer 220. The terminal block 230 may be positioned such that at least a portion of the first edge 231 is in contact with the active material layer 220. The terminal block 230 may be formed such that the first edge 231 extends not only outward from the substrate 210 but also outward from the active material layer 220.

[0117] The contact piece 230 can be formed such that the first edge 231 is located on the substrate 210, but not directly on the substrate 210. That is, at least a portion of the first edge 231 can be located on the substrate 210, while the active material layer 220 is located between the first edge 231 and the substrate 210. Accordingly, when the electrode expands, the contact piece 230 will not directly press the substrate 210 through the first edge 231.

[0118] In this way, electrode 200 can prevent cracks from forming in substrate 210.

[0119] For example, the connector 230 may further include a second edge 232. The second edge 232 connects one side of the connector 230 and the other side of the connector 230. The second edge 232 is the region of the connector 230 closest to the substrate 210 in the thickness direction (Y-axis) of the connector 230. Furthermore, the second edge 232 is the region of the connector 230 located at its edge in the width direction (X-axis). Additionally, the second edge 232 is the region of the connector 230 furthest from the first edge 231 in the width direction (X-axis). For example, the position of the second edge 232 may be opposite to that of the first edge 231.

[0120] The second edge 232 may be located at least partially on the active material layer 220. Accordingly, the terminal block 230 may be formed such that the second edge 232 extends not only outward from the substrate 210, but also outward from the active material layer 220.

[0121] The contact piece 230 can be formed such that the second edge 232 is located on the substrate 210, but not directly on the substrate 210. That is, at least a portion of the second edge 232 can be located on the substrate 210, while the active material layer 220 is located between the second edge 232 and the substrate 210. Accordingly, when the electrode expands, the contact piece 230 will not directly press the substrate 210 through the second edge 232.

[0122] In this way, electrode 200 can prevent cracks from forming in substrate 210.

[0123] Simultaneously, the terminal block 230 can be configured such that at least a portion of each of the first edge 231 and the second edge 232 lies on the active material layer 220. Accordingly, in the width direction (X-axis), the width w of the terminal block 230 can be formed to be wider than the width W of the uncoated portion N.

[0124] Accordingly, one side of the terminal piece 230 can be configured such that the center of that side is bonded to the substrate 210, and the edge of the terminal piece 230 is located on the active material layer 220. In particular, due to this structure, at least a portion of the corner portion of the terminal piece 230 is located on the coated portion A.

[0125] In this way, the edge of the terminal block 230 is prevented from directly pressing against the substrate 210 due to the force from the expansion of the electrode. That is, when the expansion of the electrode occurs, the terminal block 230 will not press against the relatively fragile uncoated portion N. Accordingly, the electrode 200 according to one embodiment of the present disclosure can be protected from internal damage.

[0126] Meanwhile, the length of the portion of the connector 230 on the substrate 210 in the longitudinal direction (Z-axis) is less than or equal to the length of the substrate 210.

[0127] For example, the length of the portion of the terminal piece 230 on the substrate 210 can be the same as the length of the substrate 210. For example, the terminal piece 230 can be configured such that one end is positioned corresponding to one end of the substrate 210. In this way, the terminal piece 230 can more effectively prevent the edges or corners of the terminal piece 230 from squeezing the substrate 210 during the expansion of the electrode.

[0128] The tab 230 can extend across the uncoated portion N of the substrate 210 in the width direction (X-axis) and can extend from one coated portion A to another coated portion A. In this case, the tab 230 can extend longer in the width direction on one side and relatively shorter in the width direction on the other side. In this way, the electrode 200 can further prevent the tab 230 from applying stress to the uncoated portion N.

[0129] Alternatively, for example, the length of the tab 230 on the substrate 210 may be shorter than the length of the substrate 210. Even in this case, the tab 230 according to one embodiment of the present disclosure may be configured such that the first edge 231 and the second edge 232 are located on the active material layer 220. Accordingly, the tab 230 can prevent the corner portions, the first edge 231 and / or the second edge 232 of the tab 230 from applying stress to the substrate 210 and causing cracks in the uncoated portion N.

[0130] Furthermore, in the XZ plane, the region of the terminal piece 230 on the substrate 210 can be formed to be wider than the region of the uncoated portion N. Additionally, in the XZ plane, the width of the terminal piece 230 can be formed to be larger than the width of the uncoated portion N. In this case, all edges of the terminal piece 230 are positioned in locations where it is difficult to apply stress to the uncoated portion N. Accordingly, the electrode 200 can mitigate cracking of the terminal piece 230 in the uncoated portion N.

[0131] Figure 7 This is a cross-sectional view illustrating an example of the thickness of a connector according to one embodiment of the present disclosure.

[0132] Figure 8 This is a cross-sectional view illustrating an example of a reinforcing layer according to one embodiment of the present disclosure.

[0133] exist Figure 7 and Figure 8 In the diagram, 200 represents an electrode (e.g., including) according to an embodiment of the present disclosure. Figures 1 to 6 (The electrodes described in the text).

[0134] As described above, electrode 200 includes a terminal piece 230 formed having a relatively wide width w. In this case, electrode 200 is wound to form electrode assembly 40. As electrode 200 is wound, terminal piece 230 also needs to be wound.

[0135] Accordingly, the terminal piece 230 needs to be formed to have a sufficiently thin thickness for winding. For example, the terminal piece 230 may be formed to have a thickness of 100 μm or less. Alternatively, for example, the terminal piece 230 may be formed to have a thickness of 95 μm or less. As yet another example, the terminal piece 230 may be formed to have a thickness of 90 μm or less. In another example, the terminal piece 230 may be formed to have a thickness of 85 μm or less. In yet another example, the terminal piece 230 may be formed to have a thickness of 80 μm or less. When the thickness of the terminal piece 230 exceeds 100 μm, the terminal piece 230 cannot be wound and may instead damage the adjacent electrode 200. Therefore, preferably, the terminal piece 230 is formed to have a thickness of 100 μm or less.

[0136] For example, the terminal piece 230 can be formed to have a thickness t that is less than or equal to the thickness T of the active material layer 220. In this way, the terminal piece 230 can be easily wound.

[0137] Electrode 200 may further include a reinforcing layer 240 provided on (e.g., attached to) at least a portion of the terminal piece 230. The reinforcing layer 240 may be located on substrate 210 while covering the terminal piece 230. Additionally, the reinforcing layer 240 may be located on a portion of active material layer 220 while covering the terminal piece 230.

[0138] The reinforcing layer 240 can strengthen the terminal block 230. In addition, the reinforcing layer 240 can protect the terminal block 230.

[0139] The reinforcing layer 240 can be formed as a strip that can be attached to the connector 230.

[0140] For example, reinforcing layer 240 may include a conductive polymer. Furthermore, reinforcing layer 240 may further include an adhesive material for adhering the conductive polymer to the tab 230.

[0141] Alternatively, the reinforcing layer 240 can be secured to the terminal block 230 by engaging it with the terminal block 230.

[0142] The reinforcing layer 240 may include a metal. For example, when electrode 200 is the positive electrode 10, the reinforcing layer 240 may include aluminum, an aluminum-coated metal, aluminum coated with another material, or an alloy comprising aluminum. Alternatively, when electrode 200 is the negative electrode 20, the reinforcing layer 240 may include copper, a copper-coated metal, copper coated with another material, or an alloy comprising copper. In this way, the reinforcing layer 240 may include the same material as the connector 230. This improves the welding strength between the reinforcing layer 240 and the connector 230.

[0143] However, the material included in the reinforcing layer 240 may not only include the same material as that included in the terminal block 230, but may also include any material having good solderability with the material included in the terminal block 230. For example, when the terminal block 230 includes copper, the reinforcing layer 240 may include at least one material selected from those having good solderability with copper, such as iron (Fe), SUS, nickel (Ni), gold (Ag), silver (Au), or combinations thereof.

[0144] Alternatively, the terminal piece 230 can be formed to have a thickness t that exceeds the thickness T of the active material layer 220. For example, the terminal piece 230 can be formed to have a thickness t that is less than or equal to 100 μm and exceeds the thickness T of the active material layer 220. In this case, the terminal piece 230 can be wound and has high strength without a separate reinforcing layer 240.

[0145] With this structure, the terminal block 230 can be formed to have an appropriate thickness t.

[0146] Figure 9 This is a top view illustrating an example of a welded portion according to one embodiment of the present disclosure.

[0147] Figure 10 This is a top view illustrating an example of a welded portion according to one embodiment of the present disclosure.

[0148] exist Figure 9 and Figure 10 In the diagram, 200 represents an electrode (e.g., including) according to an embodiment of the present disclosure. Figures 1 to 8 (The electrodes described in the text).

[0149] For example, the connector 230 can be electrically connected to the substrate 210, and simultaneously form a solder portion j with the substrate 210. The connector 230 can contact the substrate 210 via the solder portion j.

[0150] The weld portion j can be formed by joining the terminal piece 230 and the substrate 210 by welding. The weld portion j can also be formed by joining a portion of the terminal piece 230 with at least a portion of the uncoated portion N. For example, the weld portion j can be formed by various joining methods such as ultrasonic welding, laser welding, etc. In this way, the electrode 200 can be configured such that a portion of the terminal piece 230 is located on the active material layer 220 and another portion of the terminal piece 230 is electrically connected to the substrate 210.

[0151] For example, welded portion j may include a first welded portion j1 ​​or j3 positioned spaced apart from each other, and a second welded portion j2 or j4. For example, as... Figure 9 As illustrated, the weld portion j may include a first weld portion j1 ​​and a second weld portion j2 positioned spaced apart in the width direction (X-axis). Alternatively, for example, as shown... Figure 10 As illustrated in the figure, the welded portion j may include a first welded portion j3 and a second welded portion j4 positioned spaced apart in the longitudinal direction (Z-axis).

[0152] Alternatively, although not illustrated, weld portion j can be formed as a weld portion j spanning a width region. For example, weld portion j can be formed with a region having a size less than or equal to that of the uncoated portion N. For example, weld portion j can be formed as a weld portion j that is elongated in the longitudinal direction (Z-axis).

[0153] In this way, the weld portion j can be formed across a width region or in various shapes. This allows the weld portion j to be securely fixed to the substrate 210, even if the terminal block 230 is formed relatively wide.

[0154] At the same time, Figures 4 to 8 For ease of explanation, the welding part j is omitted. Correspondingly, in Figures 4 to 8 In the implementation methods described herein, further forms can be made Figure 9 and Figure 10 The welding part j described in the text.

[0155] Figure 11 This is a cross-sectional view illustrating an example of an insulating tape according to one embodiment of the present disclosure.

[0156] exist Figure 11 In the diagram, 200 represents an electrode (e.g., including) according to an embodiment of the present disclosure. Figures 1 to 10 (The electrodes described in the text).

[0157] For example, electrode 200 may further include an insulating strip 250, which includes an insulating material and covers the terminal block 230.

[0158] For example, when the diaphragm between electrodes 200 is torn, electrodes 200 can come into contact with each other. When the terminal piece 230 comes into contact with an adjacent electrode, the insulating tape 250 prevents a short circuit at the electrode 200. Furthermore, the insulating tape 250 protects the terminal piece 230 from external forces.

[0159] For this purpose, the insulating tape 250 can be attached to the connecting piece 230.

[0160] For example, such as Figure 11 As illustrated, the insulating tape 250 can be attached to one surface of the substrate 210, while also covering the terminal piece 230. Furthermore, the insulating tape 250 can be attached to extend to the upper portion of the active material layer 220, while also covering the terminal piece 230.

[0161] In addition, with Figure 11 As illustrated, the insulating tape 250 can also be attached to the uncoated portion N where the connecting piece 230 is not located, with the substrate 210 between the insulating tapes 250. That is, the insulating tape 250 can be attached to at least a portion of the coated portion A and the uncoated portion N, and can be attached to both sides of at least a portion of the coated portion A and the uncoated portion N. In this way, the electrode 200 can ensure safety in relation to other electrodes and / or diaphragms located on one side and the other side of the electrode 200.

[0162] In addition, insulating tape 250 can be used with Figure 8 The reinforcing layer 240 shown in the figure is provided together. In this case, the electrode 200 may include: a terminal piece 230; the reinforcing layer 240 located on at least a portion of the terminal piece 230; and an insulating tape 250 located on at least a portion of the reinforcing layer 240.

[0163] The insulating tape 250 may include insulating material.

[0164] For example, the insulating material may include at least one selected from the group consisting of polyimide (PI), polysulfone, polyurethane (PU), polyamide, 6,6-nylon, polycarbonate (PC), polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET).

[0165] Meanwhile, the insulating tape 250 may further include an adhesive material that attaches to the substrate 210, the active material layer 220, the connecting piece 230 and / or the reinforcing layer 240 by utilizing the adhesiveness of the insulating material.

[0166] For example, adhesive materials may include at least one of silicone resins, acrylic resins, polyurethane resins, rubber resins, epoxy resins, polyolefins, and combinations thereof.

[0167] For example, acrylic resins may include acrylic acid, ester copolymers, ethyl acrylate, butyl acrylate, hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, lauryl acrylate, acrylic acid, maleic acid, fumaric acid, itaconic acid, krypton acid, acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, acrylonitrile, acryloylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, etc.

[0168] For example, polyurethane-based resins can include polyurethane, etc.

[0169] For example, rubber-based resins can include natural rubber, synthetic rubber, etc.

[0170] Thus, an electrode 200 according to one embodiment of the present disclosure can provide protection for each component included in the electrode 200.

[0171] A secondary battery according to one embodiment of the present disclosure may include: an electrode assembly formed by winding an electrode and a separator; and a housing housing the electrode assembly, wherein the electrode may include the electrode of any of the above embodiments.

[0172] According to one embodiment of this disclosure, electrodes and / or secondary batteries with improved reliability can be provided.

[0173] According to one embodiment of this disclosure, electrodes and / or secondary batteries in which cracks are prevented or mitigated can be provided.

[0174] However, the effects that can be obtained through this disclosure are not limited to those described above, and those skilled in the art will clearly understand other technical effects not mentioned in the following description of this disclosure.

[0175] Although the present disclosure has been described above with reference to limited embodiments and accompanying drawings, the present disclosure is not limited thereto, and those skilled in the art to which the present disclosure pertains can make various modifications and changes within the scope of the technical concept of the present disclosure.

Claims

1. An electrode, comprising: substrate; An active material layer is provided on a portion of the substrate; and A terminal block is in contact with the substrate, wherein at least a portion of the terminal block is located on the active material layer.

2. The electrode according to claim 1, wherein, The terminal block is formed such that a first side of the terminal block contacts the substrate, and a second side of the terminal block extends away from the substrate. The connector includes a first edge that connects the first side and the second side.

3. The electrode according to claim 2, wherein, At least a portion of the first edge is located on the active material layer.

4. The electrode according to claim 3, wherein, The connector further includes a second edge, the second edge being located on the connector at the position furthest from the first edge in the width direction of the connector, and At least a portion of the second edge is located on the active material layer.

5. The electrode according to claim 2, wherein, The terminal block is positioned such that at least a portion of the first edge is in contact with the active material layer.

6. The electrode according to claim 1, wherein, The length of the portion of the terminal block on the substrate is the same as or less than the length of the substrate.

7. The electrode according to any one of claims 1 to 5, wherein, The electrode further includes: The coating portion, wherein the active material layer is provided on the substrate on the coating portion; and In the uncoated portion, the active material layer is not provided on the substrate, wherein the terminal block is formed to have a width wider than the uncoated portion.

8. The electrode according to any one of claims 1 to 5, wherein, The terminal block is formed to have a thickness less than or equal to the thickness of the active material layer, and The electrode further includes a reinforcing layer attached to the terminal block.

9. The electrode according to any one of claims 1 to 5, wherein, The terminal block has a thickness exceeding that of the active material layer.

10. The electrode according to any one of claims 1 to 5, further comprising: An insulating tape, the insulating tape comprising insulating material covering the terminal piece.

11. The electrode according to any one of claims 1 to 5, wherein, The terminal block is electrically connected to the substrate, and wherein the terminal block contacts the substrate via a solder portion.

12. The electrode according to claim 11, wherein, The welding portion includes a first welding portion and a second welding portion positioned spaced apart from each other.

13. A secondary battery, comprising: An electrode assembly is formed by winding an electrode and a diaphragm; and Housing, housing the electrode assembly The electrode is the electrode according to any one of claims 1 to 12.

14. The secondary battery according to claim 13, wherein, The connector has a thickness of less than 100 μm.

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