Jelly roll electrode assembly and cylindrical lithium secondary battery including the same

Abstract

To provide an electrode assembly that suppresses the occurrence of wrinkles in an electrode uncoated portion that is not coated with an electrode active material during winding, in an electrode assembly that is wound into a jelly roll shape.SOLUTION: A jelly roll electrode assembly is provided in which an uncoated electrode portion includes a protective tape on at least one side, and the protective tape satisfies the following formula 1: [Formula 1] 25%≤a1≤100%. In the formula 1, a1 is (the length of the protective tape attached to the uncoated electrode portion in the longitudinal direction of the electrode / the length of the uncoated electrode portion in the longitudinal direction of the electrode)×100%. This provides rigidity to the negative electrode current collector using the protective tape, preventing wrinkles from forming during winding, even when the process includes a winding step starting from the center of the thin negative electrode current collector. This can reduces wrinkles throughout the electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0174846, filed with the Korean Intellectual Property Office on December 8, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a jelly roll electrode assembly and a cylindrical lithium secondary battery including the same. [Background technology]

[0003] The rapid increase in fossil fuel use has led to an increasing demand for alternative and clean energy, and one of the most actively researched fields in this area is the field of power generation and storage using electrochemical reactions.

[0004] Currently, a typical example of an electrochemical element that uses such electrochemical energy is a secondary battery, and the range of its use is tending to expand more and more.

[0005] As technological development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing. Among these secondary batteries, lithium secondary batteries, which have high energy density and voltage, long cycle life, and low self-discharge rate, have been commercialized and widely used. In addition, active research is being conducted on methods for manufacturing high-density electrodes with higher energy density per unit volume as electrodes for such high-capacity lithium secondary batteries.

[0006] Generally, a secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator. The negative electrode contains a negative electrode active material that inserts and extracts lithium ions from the positive electrode. Silicon-based particles with a large discharge capacity can be used as the negative electrode active material.

[0007] Such lithium secondary batteries are typically manufactured using lithium-intercalated compounds such as LiCoO2 and LiMn2O4 as the positive electrode and non-lithium-intercalated materials such as carbon-based and Si-based materials as the negative electrode. During charging, lithium ions intercalated in the positive electrode migrate to the negative electrode via the electrolyte, and during discharging, lithium ions again migrate from the negative electrode to the positive electrode.

[0008] Lithium secondary batteries are used in various shapes, such as cylindrical, pouch, and prismatic, depending on their intended use. Conventional cylindrical cells have a separator on the outermost side after winding, and have a separator shell structure that surrounds the entire cell and is electrically connected to the battery outer can via positive and negative electrode tabs.

[0009] While conventional cylindrical cells are wound in the order of positive electrode / separator / negative electrode / separator, with the separator exposed at the outermost periphery, the Cu foil outermost periphery structure is wound in the order of negative electrode / separator / positive electrode / separator, with the Cu foil exposed at the outermost periphery. This has the advantage of being able to directly contact the inner wall of the cylindrical cell's battery outer can, electrically connected, and replacing the outer negative electrode tab.

[0010] However, if the contact between the Cu foil and the battery outer can is poor, the resistance increases, and the resistance varies depending on the outer diameter of the jelly roll. Unlike the conventional separator outer structure, the Cu foil is on the outermost periphery, so two separators 2 exist inside, surrounding the positive electrode.

[0011] The thickness of the Cu foil used as the negative electrode current collector is gradually becoming thinner. In particular, when a tab is attached to the uncoated portion of the core of the negative electrode current collector and winding is started around the core to form a jelly roll electrode assembly, wrinkles form in the uncoated portion of the core of the negative electrode current collector during winding, and these wrinkles propagate to the wrinkles in the negative electrode, resulting in a problem when the jelly roll electrode assembly is wound in this state.

[0012] Therefore, research is being conducted to improve the wrinkles in the core electrode of a jelly roll electrode assembly in which Cu foil, which is a negative electrode current collector, forms the outermost layer. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Publication No. 2009-080971 Summary of the Invention [Problem to be solved by the invention]

[0014] The present application relates to a jelly roll electrode assembly and a cylindrical lithium secondary battery including the same. [Means for solving the problem]

[0015] One embodiment of the present specification provides a jelly roll electrode assembly including: a first separator; a positive electrode stacked on one side of the first separator and including a positive electrode current collector; a second separator provided on a side of the positive electrode opposite to a side that contacts the first separator; and a negative electrode including a negative electrode current collector provided on a side of the second separator opposite to a side that contacts the positive electrode; the jelly roll electrode assembly having a jelly roll hollow formed in a core portion and wound around the negative electrode, wherein the negative electrode current collector includes a negative electrode active material-coated portion to which a negative electrode active material is coated and a negative electrode uncoated portion to which the negative electrode active material is not coated, the negative electrode uncoated portion being formed on both ends of the negative electrode, at least one of the negative electrode uncoated portions at both ends having a negative electrode tab, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side, and the protective tape satisfies the following formula 1:

[0016] [Formula 1] 50%≦a≦100% In the formula 1, a is (length of the protective tape attached to the negative electrode uncoated portion / total length of the negative electrode uncoated portion)×100%.

[0017] In another embodiment, a cylindrical lithium secondary battery is provided, including: a battery exterior; a jelly roll electrode assembly according to the present application provided inside the battery exterior; and an exterior cap having an electrode provided at an opening of the battery exterior. [Effects of the Invention]

[0018] The jelly roll electrode assembly according to the present application is a jelly roll electrode assembly having a structure in which a hollow jelly roll portion is formed in a core portion around the negative electrode to realize the outermost structure of the negative electrode current collector, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side that satisfies Equation 1. As a result, even if a winding process is performed starting from the center of the thin negative electrode current collector, the protective tape imparts rigidity to the negative electrode current collector, preventing wrinkles from forming during winding. This reduces wrinkles in the entire electrode, resulting in a wrinkle-free jelly roll electrode assembly.

[0019] That is, the jelly roll electrode assembly according to the present application is characterized in that the protective tape is formed so as to cover at least 50% of at least one side of the negative electrode uncoated portion of the negative electrode current collector, and is formed on one or both sides of the uncoated portion. This improves electrode wrinkles, thereby increasing the lifespan and efficiency of a cylindrical lithium secondary battery including the same. [Brief explanation of the drawings]

[0020] [Figure 1] 1A and 1B are diagrams illustrating a method for winding a jelly roll electrode assembly according to an embodiment of the present application. [Figure 2] 10A and 10B are diagrams illustrating a method for manufacturing a jelly roll electrode assembly having an outermost separator structure. [Figure 3] FIG. 1 is a side view of a jelly roll electrode assembly before winding in accordance with an embodiment of the present application. [Figure 4] FIG. 2 is a diagram showing a core portion of a negative electrode according to the present application. [Figure 5]FIG. 1 shows a negative electrode according to Example 1 of the present application. [Figure 6] FIG. 2 is a diagram showing a negative electrode according to Comparative Example 1 of the present application. [Figure 7] FIG. 10 is a diagram showing whether wrinkles occur in the negative electrode according to Comparative Example 1 of the present application. [Explanation of symbols]

[0021] 1...Negative electrode 2 Second separator 3...Positive electrode 4. First separator 10 Negative electrode tab 11: Protective tape attached to the uncoated surface of the first negative electrode 12: Protective tape attached to the uncoated surface of the second negative electrode 13 Positive electrode tab 14 Positive electrode uncoated area 15 Negative electrode uncoated area 16...Negative electrode active material layer 17...Cathode active material layer 21 Overall length of first negative electrode uncoated portion 22 Overall length of second negative electrode uncoated portion 23: Length of protective tape attached to the uncoated surface of the first negative electrode 24: Length of protective tape attached to the uncoated surface of the second negative electrode 100 ··· Jelly roll hollow section DETAILED DESCRIPTION OF THE INVENTION

[0022] Before describing the present invention, some terms will first be defined.

[0023] In this specification, when a part is said to "comprise" a certain component, this means that it may further include other components, rather than excluding other components, unless otherwise specified.

[0024] In this specification, "p to q" means a range of "not less than p and not more than q."

[0025] In this specification, the "specific surface area" is measured by the BET method, and specifically, is calculated from the amount of nitrogen gas adsorption at liquid nitrogen temperature (77 K) using a BELSORP-mino II manufactured by BEL Japan Co., Ltd. That is, in the present application, the BET specific surface area may mean the specific surface area measured by the above-mentioned measurement method.

[0026] In this specification, "Dn" refers to the average particle size, which is the particle size at the n% point in the cumulative particle number distribution according to particle size. That is, D50 is the particle size at the 50% point in the cumulative particle number distribution according to particle size, D90 is the particle size at the 90% point in the cumulative particle number distribution according to particle size, and D10 is the particle size at the 10% point in the cumulative particle number distribution according to particle size. Meanwhile, the average particle size can be measured using the laser diffraction method. Specifically, the powder to be measured is dispersed in a dispersion medium and then introduced into a commercially available laser diffraction particle size analyzer (e.g., Microtrac S3500). The particle size distribution is calculated by measuring the difference in the diffraction pattern according to the particle size when the particles pass through a laser beam.

[0027] As used herein, when a polymer contains a certain monomer as a monomer unit, it means that the monomer participates in a polymerization reaction and is contained as a repeating unit in the polymer. When a polymer contains a monomer, this is interpreted as meaning that the polymer contains the monomer as a monomer unit.

[0028] In this specification, the term "polymer" is understood to be used in a broad sense, including copolymers, unless otherwise specified as a "homopolymer."

[0029] In this specification, the weight average molecular weight (Mw) and number average molecular weight (Mn) are polystyrene-equivalent molecular weights measured by gel permeation chromatography (GPC) using commercially available monodisperse polystyrene polymers (standard samples) with various degrees of polymerization as standard substances for molecular weight measurement. In this specification, molecular weight means weight average molecular weight unless otherwise specified.

[0030] The present invention will now be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the present invention, although the present invention may be embodied in various different forms and is not limited to the following description.

[0031] One embodiment of the present specification provides a jelly roll electrode assembly including: a first separator; a positive electrode stacked on one side of the first separator and including a positive electrode current collector; a second separator provided on a side of the positive electrode opposite to a side that contacts the first separator; and a negative electrode including a negative electrode current collector provided on a side of the second separator opposite to a side that contacts the positive electrode; the jelly roll electrode assembly having a jelly roll hollow formed in a core portion and wound around the negative electrode, wherein the negative electrode current collector includes a negative electrode active material-coated portion to which a negative electrode active material is coated and a negative electrode uncoated portion to which no negative electrode active material is coated, the negative electrode uncoated portion being formed on both ends of the negative electrode, and at least one of the negative electrode uncoated portions at both ends having a negative electrode tab; and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side, the protective tape satisfying the following formula 1:

[0032] [Formula 1] 50%≦a≦100% In the formula 1, a is (length of protective tape attached to negative electrode uncoated portion / total length of negative electrode uncoated portion)×100%.

[0033] The jelly roll electrode assembly according to the present application is a jelly roll electrode assembly having a structure in which a hollow jelly roll portion is formed in the center around the negative electrode to realize the outermost structure of the negative electrode current collector, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side that satisfies Equation 1. As a result, even if a winding process is performed starting from the center of the thin negative electrode current collector, the protective tape imparts rigidity to the negative electrode current collector, preventing wrinkles from forming during winding. This improves wrinkles in the entire electrode, thereby providing a wrinkle-free jelly roll electrode assembly.

[0034] In one embodiment of the present application, a first separator, a positive electrode laminated on one side of the first separator and including a positive electrode current collector, a second separator laminated on one side of the positive electrode, and a negative electrode including a negative electrode current collector on the second separator can be represented as an electrode sheet.

[0035] That is, a jelly roll electrode assembly including a first separator; a positive electrode stacked on one side of the first separator and including a positive electrode current collector; a second separator provided on the side of the positive electrode opposite to the side that contacts the first separator; and a negative electrode including a negative electrode current collector provided on the side of the second separator opposite to the side that contacts the positive electrode, and having a jelly roll hollow portion formed in a core portion and wound around the negative electrode, can be referred to as a jelly roll electrode assembly having a structure in which the electrode sheet is wound.

[0036] In one embodiment of the present application, the method for manufacturing a jelly roll electrode assembly includes the steps of respectively preparing and stacking a positive electrode, a negative electrode, a first separator, and a second separator.

[0037] In the above steps, the first separator, the positive electrode, the second separator, and the negative electrode are stacked in this order, and a jelly roll hollow portion is formed in the core portion and wound around the negative electrode. By using the above stacking and winding method, a jelly roll electrode assembly having a negative electrode current collector as the outermost structure can be formed.

[0038] 1 is a diagram illustrating a method for winding an electrode sheet into a jelly roll electrode assembly according to one embodiment of the present disclosure. Specifically, the electrode sheet includes a first separator 4, a positive electrode 3 including a positive current collector stacked on one side of the first separator, a second separator 2 stacked on one side of the positive electrode 3, and a negative electrode 1 including a negative current collector stacked on the second separator 2. The jelly roll electrode assembly includes a hollow jelly roll 100 at the center, and is wound around the negative electrode 1. Furthermore, as can be seen from FIG. 1, the negative electrode 1 including the negative current collector is separately wound again to form a jelly roll electrode assembly with the negative electrode current collector at the outermost edge.

[0039] FIG. 2 shows the outermost structure of a conventional separator, which has a positive electrode 3 / second separator 2 / negative electrode 1 / first separator 4 configuration. A jelly roll hollow 100 is formed in the center and wound around the positive electrode 3. The resulting jelly roll electrode assembly has an outermost structure of the first separator 4.

[0040] In one embodiment of the present application, the positive electrode may include a positive electrode current collector and a positive electrode active material layer formed on one or both sides of the positive electrode current collector and containing a positive electrode active material.

[0041] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the positive electrode current collector includes a positive electrode active material-coated portion on which a positive electrode active material is coated and a positive electrode uncoated portion on which no positive electrode active material is coated, and a positive electrode tab is provided on the positive electrode uncoated portion.

[0042] In one embodiment of the present application, the positive electrode active material layer is formed on an active material-coated portion of the positive electrode current collector, and a surface on which the positive electrode active material layer is not provided can be referred to as a positive electrode uncoated portion.

[0043] Specifically, as can be seen from FIG. 3, the positive electrode 3 is disposed between the first separator 4 and the second separator 2, and the positive electrode 3 includes a positive electrode uncoated portion 14 where the positive electrode active material layer 17 is not applied, and a positive electrode tab 13 is disposed on the uncoated portion.

[0044] The positive electrode current collector in the positive electrode is not particularly limited as long as it does not induce chemical changes in the battery and is conductive. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like may be used. The positive electrode current collector may typically have a thickness of 3 to 500 μm, and the surface of the current collector may be formed with fine irregularities to enhance the adhesive strength of the positive electrode active material. The positive electrode current collector may be used in various forms, such as a film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0045] The positive electrode active material may be a commonly used positive electrode active material. Specifically, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; a lithium iron oxide such as LiFe3O4; 1+c1 Mn 2-c1 O4 (0≦c1≦0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, and Cu2V2O7; chemical formula LiNi 1-c2 Ni-site type lithium nickel oxide represented by the chemical formula LiMn 2-c3 M c3Examples of suitable lithium manganese composite oxides include, but are not limited to, lithium manganese composite oxides represented by Li2Mn3MO8 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfying 0.01≦c3≦0.1) or Li2Mn3MO8 (where M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); and LiMn2O4, in which part of the Li in the chemical formula is replaced with an alkaline earth metal ion. The positive electrode may be Li-metal.

[0046] The positive electrode active material layer may contain a positive electrode conductive material and a positive electrode binder in addition to the above-described positive electrode active material.

[0047] In this case, the positive electrode conductive material is used to impart conductivity to the electrode, and can be any material that has electronic conductivity without causing chemical changes in the battery that is constructed. Specific examples include graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives. These materials may be used alone or in combination.

[0048] The positive electrode binder improves adhesion between positive electrode active material particles and between the positive electrode active material and the positive electrode current collector. Specific examples of the positive electrode binder include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, and various copolymers thereof. One or more of these may be used alone or in combination.

[0049] In one embodiment of the present application, the positive electrode current collector may include a positive electrode uncoated portion and a positive electrode tab formed on the positive electrode uncoated portion, and the jelly roll electrode assembly according to the present application may include one positive electrode tab.

[0050] In this case, the positive electrode uncoated portion may be formed in the center of the positive electrode.

[0051] In one embodiment of the present application, the negative electrode may include a negative electrode current collector; and a negative electrode active material layer, and the negative electrode current collector may include a negative electrode active material-coated portion to which the negative electrode active material is coated, and a negative electrode uncoated portion to which the negative electrode active material is not coated.

[0052] Specifically, as can be seen from FIG. 3, the negative electrode 1 is disposed on a second separator 2, and the negative electrode 1 includes negative electrode uncoated areas 15 at both ends of the negative electrode where the negative electrode active material layer 16 is not applied, and at least one of the negative electrode uncoated areas at both ends is provided with a negative electrode tab 10.

[0053] The jelly roll electrode assembly according to the present application includes negative electrode uncoated portions at both ends of the negative electrode, and at least one of the negative electrode uncoated portions at both ends includes a negative electrode tab. Specifically, the negative electrode uncoated portion on the winding core side may include a negative electrode tab.

[0054] In one embodiment of the present application, the negative electrode active material layer may include a negative electrode active material including one or more selected from the group consisting of silicon-based materials and carbon-based materials.

[0055] In one embodiment of the present application, the negative electrode active material layer may include a negative electrode conductive material; and a negative electrode binder.

[0056] In one embodiment of the present application, the negative electrode active material, negative electrode conductive material, and negative electrode binder may be any materials used in the art without limitation.

[0057] In one embodiment of the present application, the negative electrode current collector is not particularly limited as long as it does not induce chemical changes in the battery and is conductive. For example, the current collector may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel whose surface has been treated with carbon, nickel, titanium, silver, or the like. Specifically, a transition metal that easily adsorbs carbon, such as copper or nickel, may be used as the current collector. The thickness of the current collector may be 6 μm to 20 μm, but is not limited thereto.

[0058] The negative electrode binder may include at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, polyacrylic acid, and substances in which hydrogen is substituted with Li, Na, Ca, or the like, or may include various copolymers thereof.

[0059] The negative electrode conductive material is not particularly limited as long as it does not induce a chemical change in the battery and has conductivity, and examples thereof include graphite such as natural graphite and artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0060] In one embodiment of the present application, the first separator and the second separator separate the negative electrode and the positive electrode and provide a path for lithium ion migration. Any separator typically used as a separator in a secondary battery can be used without particular limitation. In particular, a separator that exhibits low resistance to electrolyte ion migration and excellent electrolyte humidification capability is preferred. Specifically, a porous polymer film, such as a porous polymer film made from a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminate structure of two or more layers thereof, may be used. Conventional porous nonwoven fabrics, such as nonwoven fabrics made from high-melting-point glass fibers or polyethylene terephthalate fibers, may also be used. To ensure heat resistance or mechanical strength, a separator coated with a ceramic component or a polymer material may be used, and may be selectively used as a single-layer or multi-layer structure.

[0061] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the negative electrode current collector includes a negative electrode active material-coated portion on which a negative electrode active material is coated and a negative electrode uncoated portion on which no negative electrode active material is coated, the negative electrode uncoated portions are formed on both ends of the negative electrode, at least one of the negative electrode uncoated portions on both ends has a negative electrode tab, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side, and the protective tape satisfies the following formula 1:

[0062] [Formula 1] 50%≦a≦100% In the formula 1, a is (length of the protective tape attached to the negative electrode uncoated portion / total length of the negative electrode uncoated portion)×100%.

[0063] In one embodiment of the present application, the negative electrode uncoated portion may be formed at both ends of the negative electrode, one of which may be formed in the hollow portion of the jelly roll. Specifically, this corresponds to the position 100 in FIG. 1 and may refer to the portion of the end of the negative electrode where winding begins, as can be seen in FIG. 3.

[0064] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the negative electrode current collector includes a negative electrode active material-coated portion where a negative electrode active material is coated and a negative electrode uncoated portion where no negative electrode active material is coated, the negative electrode uncoated portions are formed on both ends of the negative electrode, one of the negative electrode uncoated portions at both ends has a negative electrode tab, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side, and the protective tape satisfies Equation 1.

[0065] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the negative electrode current collector includes a negative electrode active material-coated portion on which a negative electrode active material is coated and a negative electrode uncoated portion on which no negative electrode active material is coated, the negative electrode uncoated portions are formed on both ends of the negative electrode, one of the negative electrode uncoated portions at both ends has a negative electrode tab, and the negative electrode tab is located at an end of the negative electrode uncoated portion that is located in a hollow portion of the negative electrode jelly roll, and the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one side, and the protective tape satisfies Equation 1.

[0066] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one surface thereof, and the protective tape satisfies Formula 1 above.

[0067] In another embodiment, there is provided a jelly roll electrode assembly, wherein the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on one surface thereof, and the protective tape satisfies Formula 1 above.

[0068] In yet another embodiment, there is provided a jelly roll electrode assembly, wherein the negative electrode uncoated portion of the negative electrode current collector includes protective tapes on both sides thereof, and the protective tapes satisfy Formula 1 above.

[0069] The jelly roll electrode assembly according to the present application includes a protective tape that satisfies Formula 1 on at least one surface of the negative electrode uncoated portion of the negative electrode current collector. This provides rigidity to the negative electrode current collector and prevents wrinkles from forming during winding, even when a winding process is performed starting from the center of the thin negative electrode current collector. This improves electrode wrinkles throughout the electrode, resulting in a wrinkle-free jelly roll electrode assembly.

[0070] That is, the main object of the present invention is to provide a feature that can solve the problem of wrinkles occurring in conventional electrodes when a protective tape having the above-mentioned length is attached to at least one surface of the negative electrode uncoated portion of the jelly roll electrode assembly according to the present application.

[0071] In one embodiment of the present application, there is provided a jelly roll electrode assembly, in which the negative electrode uncoated portion includes a first negative electrode uncoated surface on which the negative electrode tab is provided; and a second negative electrode uncoated surface opposite to the first negative electrode uncoated surface, and the protective tape is formed on the first negative electrode uncoated surface and the second negative electrode uncoated surface, and the protective tape satisfies the following Equations 2 and 3:

[0072] [Formula 2] 25%≦a1≦100% [Formula 3] 25%≦b1≦100% In the formula 2 and formula 3, a1 is (length of protective tape attached to first negative-electrode uncoated portion / total length of first negative-electrode uncoated portion) × 100%, b1 is (length of protective tape attached to second negative-electrode uncoated portion / total length of second negative-electrode uncoated portion) × 100%, At least one of a1 and b1 is 50% or more.

[0073] Specifically, the above can be confirmed from Figure 4. Figure 4 is a diagram showing a core part of a negative electrode according to the present application. Specifically, a negative electrode tab 10 is provided on a negative electrode uncoated portion included in the core part at both ends of the negative electrode. The length 23 of the protective tape attached to the first negative electrode uncoated portion and the total length 21 of the first negative electrode uncoated portion can be confirmed, and the length 24 of the protective tape attached to the second negative electrode uncoated portion and the total length 22 of the second negative electrode uncoated portion can also be confirmed.

[0074] In one embodiment of the present application, the formula 2 may satisfy the range of 25%≦a1≦100%, may satisfy the range of 50%≦a1≦100%, or may satisfy the range of 70%≦a1≦100%.

[0075] In one embodiment of the present application, the protective tape attached to the first negative electrode uncoated portion is formed in a structure that covers the negative electrode tab, and has the characteristics of fixing the negative electrode tab and preventing wrinkles in the uncoated portion of the negative electrode current collector during winding.

[0076] In one embodiment of the present application, the formula 3 may satisfy the range of 25%≦b1≦100%, may satisfy the range of 50%≦b1≦100%, or may satisfy the range of 70%≦b1≦100%.

[0077] In one embodiment of the present application, when a protective tape is included in a first negative electrode uncoated portion where a negative electrode tab is provided among the negative electrode uncoated portions, and a protective tape satisfying the above range is also included in a second negative electrode uncoated portion on the opposite side, the rate of core wrinkles is significantly reduced compared to when protective tapes are provided on only one side.

[0078] That is, when a protective tape having the above-mentioned length is attached to one surface of the negative electrode uncoated portion of the jelly roll electrode assembly, the problem of wrinkles occurring in conventional electrodes can be resolved. At the same time, particularly when protective tape is provided on both the first negative electrode uncoated portion and the second negative electrode uncoated portion of the negative electrode uncoated portion, in addition to the problem of wrinkles, the rigidity of the jelly roll-shaped core portion provides an advantage of being more effective in preventing core collapse.

[0079] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein a1 is 100% and b1 is 100%.

[0080] In the present application, when a1 is 100% and b1 is 100%, it may mean that the entire surfaces of both sides of the negative electrode uncoated portion where the negative electrode tab is provided are covered with the protective tape.

[0081] In one embodiment of the present application, a jelly roll electrode assembly is provided, which includes one positive electrode tab and one negative electrode tab.

[0082] As can be seen from FIG. 3, the negative electrode tab of the jelly roll electrode assembly according to the present invention is located at the end of the negative electrode that is located at the core portion of the negative electrode, and the positive electrode tab is located at the center of the positive electrode, not at the outer periphery of the positive electrode. Therefore, one positive electrode tab and one negative electrode tab may be included.

[0083] When one positive electrode tab and one negative electrode tab are included as described above, the resistance may be higher than when two or more are included. However, by including one each, the uncoated area can be reduced and more positive electrode active material and negative electrode active material can be included, resulting in a significant increase in capacity.

[0084] That is, the jelly roll electrode assembly according to the present invention includes one positive electrode tab and one negative electrode tab, and is used for high capacity applications rather than high power applications. Therefore, different purposes can be identified depending on the number of positive electrode tabs and negative electrode tabs.

[0085] In one embodiment of the present application, there is provided a jelly roll electrode assembly including: a positive electrode active material layer provided on both sides of the positive electrode active material-coated portion of the positive electrode current collector; and a negative electrode active material layer provided on both sides of the negative electrode active material-coated portion of the negative electrode current collector.

[0086] When the active material layer is included on both sides as described above, the active material can be contained in a larger amount, which maximizes the capacity.

[0087] In one embodiment of the present application, there is provided a jelly roll electrode assembly in which a negative electrode current collector is an outermost structure.

[0088] A manufacturing method for forming the outermost structure of the negative electrode current collector can be seen in Figure 1. As can be seen from Figure 1, a jelly roll hollow portion 100 is formed in the center, and the negative electrode 1 is wound around it. Finally, only the negative electrode current collector included in the negative electrode 1 is wound again around the outer edge of the jelly roll electrode assembly, forming an outermost exposed structure of the negative electrode current collector.

[0089] That is, the outermost structure of the negative electrode current collector is a structure in which the winding order of the positive and negative electrodes is reversed so that the negative electrode current collector is exposed at the outermost edge, allowing direct contact between the negative electrode current collector and the inner wall of the battery outer casing material described below, and enabling electrical connection to the can even without an outer negative electrode tab. That is, as described above, the jelly roll electrode assembly according to the present invention includes one positive electrode tab and one negative electrode tab, thereby enabling a high-capacity battery, and the above features are achieved by forming the negative electrode current collector at the outermost edge.

[0090] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the protective tape is any one selected from the group consisting of polyethylene terephthalate (PET), polypropylene (PP), polyester, polycarbonate (PC), polyimide (PI), polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyarylate (PAR), polycylicolefin (PCO), polynorbornene (polynorbornene), polyethersulphone (PES), and cycloolefin polymer (COP).

[0091] The protective tape can be any tape that can fix the negative electrode tab and has enough rigidity to prevent the negative electrode uncoated portion from bending when wound up, and specifically, PET may be used.

[0092] In one embodiment of the present application, there is provided a jelly roll electrode assembly, wherein the thickness of the protective tape is 10 μm or more and 100 μm or less.

[0093] In one embodiment of the present application, a cylindrical lithium secondary battery is provided, including: a battery exterior material; a jelly roll electrode assembly according to the present application provided inside the battery exterior material; and an exterior cap having an electrode provided at an opening of the battery exterior material.

[0094] The components included in the jelly roll electrode assembly are as described above.

[0095] In one embodiment of the present application, the battery exterior material may contain an electrolyte inside.

[0096] Examples of the electrolyte include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in manufacturing lithium secondary batteries.

[0097] Specifically, the electrolyte may include a non-aqueous organic solvent and a metal salt.

[0098] Examples of the non-aqueous organic solvent that can be used include aprotic organic solvents such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, and ethyl propionate.

[0099] In particular, among the carbonate organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, can be preferably used as high-viscosity organic solvents, because they have a high dielectric constant and dissociate lithium salts well. When such cyclic carbonates are mixed in an appropriate ratio with linear carbonates having low viscosity and low dielectric constants, such as dimethyl carbonate and diethyl carbonate, an electrolyte having high electrical conductivity can be prepared, and therefore such cyclic carbonates can be used more preferably.

[0100] The metal salt may be a lithium salt, which is a substance that is easily dissolved in the non-aqueous electrolyte solution. For example, the anion of the lithium salt may be F - , Cl - , I - , NO3 -, N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - One or more selected from the group consisting of:

[0101] In addition to the constituent components of the electrolyte, the electrolyte may further include one or more additives, such as a haloalkylene carbonate compound such as difluoroethylene carbonate, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinoneimine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing a decrease in battery capacity, and improving the discharge capacity of the battery.

[0102] The jelly roll electrode assembly according to the present invention may be included in a cylindrical battery. The cylindrical battery may refer to a battery having a cylindrical shape, including an assembly including a positive electrode, a negative electrode, a separator, and an electrolyte. Specifically, the cylindrical battery may be composed of a cylindrical can, a battery assembly provided inside the cylindrical can, and a top cap. [Example]

[0103] Below, preferred examples are presented to help understand the present invention, but these examples are merely for the purpose of illustrating the present description, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present description, and it is natural that such changes and modifications fall within the scope of the appended claims.

[0104] Example 1 As shown in Figure 3, a first separator / positive electrode / second separator / negative electrode were stacked, and a negative electrode tab was attached to the center of the uncoated portion of the negative electrode current collector where it was wound. Protective tapes with a of 100%, specifically a1 of 100% and b1 of 100%, were attached to both sides of the uncoated portion of the negative electrode current collector where the negative electrode tab was attached, and then wound up to form a jelly roll electrode assembly.

[0105] <Example 2> A jelly roll electrode assembly was formed in the same manner as in Example 1, except that a protective tape in which a was 100%, specifically a1 was 100%, was attached to one side of the uncoated portion of the negative electrode current collector on which the negative electrode tab was provided.

[0106] Example 3 A jelly roll electrode assembly was formed in the same manner as in Example 1, except that protective tapes in which a was 80%, specifically, a1 was 80% and b1 was 30%, were attached to both surfaces of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided.

[0107] Example 4 A jelly roll electrode assembly was formed in the same manner as in Example 1, except that protective tapes in which a was 80%, specifically, a1 was 30% and b1 was 80%, were attached to both surfaces of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided.

[0108] <Comparative Example 1> A jelly roll electrode assembly was formed in the same manner as in Example 1, except that a protective tape in which a was 40%, specifically a1 was 40%, was attached to one side of the uncoated portion of the negative electrode current collector on which the negative electrode tab was provided.

[0109] <Comparative Example 2> A jelly roll electrode assembly was formed in the same manner as in Example 1, except that protective tapes in which a was 40%, specifically, a1 was 40% and b1 was 30%, were attached to both sides of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided.

[0110] <Comparative Example 3> A jelly roll electrode assembly was formed in the same manner as in Example 1, except that no protective tape was attached to both sides of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided.

[0111] The jelly roll electrode assemblies of Examples 1 to 4 are characterized in that the protective tape is formed on one or both sides of the negative electrode uncoated portion of the negative electrode current collector so as to cover 50% or more of the negative electrode uncoated portion. This reduces electrode wrinkles, thereby improving the lifespan and efficiency of cylindrical lithium secondary batteries including the same.

[0112] Specifically, in Example 1, the protective tape was attached to 100% of both sides of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided, and in Example 2, the protective tape was attached to 100% of the uncoated portion of the negative electrode current collector where the negative electrode tab was provided.

[0113] Comparing Example 1 and Example 2, it was confirmed that Example 1 had a greater effect of improving electrode wrinkles than Comparative Examples 1 to 3, and was particularly superior in improving electrode wrinkles compared to Example 2 (protective tape formed on one side). This is the result of forming rigid protective tape on both sides of the plain area.

[0114] In particular, Figure 5 shows the negative electrode according to Example 1 of the present application. Specifically, protective tape was attached to both sides of the negative electrode uncoated area (shown by the dotted line) so that a was 100%. In this case, it was confirmed that no wrinkles occurred in the negative electrode, demonstrating the effect of reducing wrinkles in the electrode.

[0115] In Examples 3 and 4, protective tape was applied to both sides of the negative electrode current collector uncoated portion where the negative electrode tab was provided, except that a1 and b1 were not 100%. Although there was a small amount of wrinkling in the electrode compared to Example 1, it was confirmed that the electrode wrinkling was improved to the extent that it did not affect the operation of the electrode.

[0116] In Comparative Example 1, protective tape was formed on one side of the negative electrode uncoated region, and in Comparative Example 2, protective tape was formed on both sides of the negative electrode uncoated region, but in each case, the protective tape coverage was less than 50%. It was confirmed that even with the protective tape, wrinkles still occurred in the electrode when the electrode assembly was wound up, which may cause performance degradation of the lithium secondary battery and safety issues due to lithium precipitation.

[0117] Figure 6 is a diagram showing a negative electrode according to Comparative Example 1 of the present application. Specifically, in the negative electrode uncoated area (shown by the thin dotted line), protective tape was attached to one side so that a filled 40% of the negative electrode uncoated area, leaving 60% of the negative electrode uncoated area exposed. In this case, as can be seen from Figures 6 and 7, the length of the protective tape could not be filled, and wrinkles occurred in the negative electrode uncoated area (enlargement of the thick dotted line). This resulted in wrinkles occurring throughout the negative electrode, causing a decrease in the performance of the lithium secondary battery.

[0118] Comparative Example 3 is a case where no protective tape is provided on both sides, and in this case, many wrinkles are generated when the electrode assembly is wound up, which may cause early performance degradation of the lithium secondary battery and safety issues due to lithium precipitation. The following items are also disclosed: [Item 1] First separator; a positive electrode including a positive electrode current collector, the positive electrode being laminated on one side of the first separator; a second separator provided on the surface of the positive electrode opposite to the surface in contact with the first separator; and a negative electrode including a negative electrode current collector provided on a surface of the second separator opposite to the surface that contacts the positive electrode; and a jelly roll electrode assembly having a structure in which a jelly roll hollow portion is formed in a core portion and wound around the negative electrode, the negative electrode current collector includes a negative electrode active material-coated portion on which a negative electrode active material is coated, and a negative electrode uncoated portion on which the negative electrode active material is not coated, The negative electrode uncoated portions are formed on both ends of the negative electrode, and at least one of the negative electrode uncoated portions on both ends has a negative electrode tab; A jelly roll electrode assembly, wherein the negative electrode uncoated portion of the negative electrode current collector includes a protective tape on at least one surface thereof, and the protective tape satisfies the following formula 1: [Formula 1] 50%≦a≦100% In the formula 1, a is (length of the protective tape attached to the negative electrode uncoated portion / total length of the negative electrode uncoated portion)×100%. [Item 2] the negative electrode uncoated portion includes a first negative electrode uncoated surface on which the negative electrode tab is provided; and a second negative electrode uncoated surface opposite to the first negative electrode uncoated surface, the protective tape is formed on the first negative electrode uncoated surface and the second negative electrode uncoated surface, Item 1. The jelly roll electrode assembly according to item 1, wherein the protective tape satisfies the following formulas 2 and 3: [Formula 2] 25%≦a1≦100% [Formula 3] 25%≦b1≦100% In the formula 2 and the formula 3, a1 is (length of protective tape attached to first negative-electrode uncoated portion / total length of the first negative-electrode uncoated portion) × 100%, b1 is (length of protective tape attached to second negative-electrode uncoated portion / total length of the second negative-electrode uncoated portion) × 100%, At least one of the a1 and the b1 is 50% or more. [Item 3] the positive electrode current collector includes a positive electrode active material-coated portion on which a positive electrode active material is coated, and a positive electrode non-coated portion on which the positive electrode active material is not coated, Item 2. The jelly roll electrode assembly of item 1, comprising a positive electrode tab on the positive electrode uncoated portion. [Item 4] 3. The jelly roll electrode assembly of claim 2, wherein a1 is 100% and b1 is 100%. [Item 5] Item 4. The jelly roll electrode assembly of item 3, comprising one positive electrode tab and one negative electrode tab. [Item 6] a positive electrode active material layer provided on both surfaces of the positive electrode active material-coated portion of the positive electrode current collector; and a negative electrode active material layer provided on both sides of the negative electrode active material-coated portion of the negative electrode current collector. [Item 7] Item 2. The jelly roll electrode assembly according to item 1, wherein the protective tape is any one selected from the group consisting of PET (polyethylene terephthalate), PP (polypropylene), polyester, PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PEEK (polyether ether ketone), PAR (polyarylate), PCO (polycylicolefin), polynorbornene, PES (polyethersulphone), and COP (cycloolefin polymer). [Item 8] Item 2. The jelly roll electrode assembly according to item 1, wherein the thickness of the protective tape is 10 μm or more and 100 μm or less. [Item 9] Item 2. The jelly roll electrode assembly according to item 1, wherein the negative electrode current collector is the outermost structure. [Item 10] Battery casing materials; The jelly roll electrode assembly according to any one of items 1 to 9, which is provided inside the battery exterior material; and an exterior cap having an electrode provided at an opening of the battery exterior material; A cylindrical lithium secondary battery comprising:

Claims

1. An electrode wound into a jelly roll shape, an electrode current collector having a first surface and a second surface opposite to the first surface, the first surface including a first electrode ground portion coated with an electrode active material and a first electrode uncoated portion not coated with the electrode active material, the second surface including a second electrode ground portion coated with the electrode active material and a second electrode uncoated portion not coated with the electrode active material, the first electrode uncoated portion and the second electrode uncoated portion extending in a longitudinal direction of the electrode from a first end of the electrode; an electrode tab disposed in the first electrode non-coating portion; a first protective tape disposed in the first electrode uncoated region, covering at least a portion of the electrode tab in the longitudinal direction of the electrode, and extending in the longitudinal direction of the electrode only within the first electrode uncoated region; a second protective tape disposed in the second electrode uncoated region, at least a portion of which faces the electrode tab, and which extends in the longitudinal direction of the electrode only within the second electrode uncoated region; Including, The first protective tape satisfies the following formula 1, and the second protective tape satisfies the following formula 2, [Formula 1] 25%≦a1≦100% [Formula 2] 25%≦b1≦100% In the formula 1 and the formula 2, a1 is (the length of the first protective tape attached to the first electrode uncoated portion in the longitudinal direction of the electrode / the length of the first electrode uncoated portion in the longitudinal direction of the electrode)×100%, b1 is (the length of the second protective tape attached to the second electrode uncoated portion in the longitudinal direction of the electrode / the length of the second electrode uncoated portion in the longitudinal direction of the electrode)×100%, At least one of a1 and b1 is 50% or more.

2. The electrode of claim 1 , wherein the electrode is a negative electrode.

3. The electrode according to claim 1 , wherein the first protective tape extends from an end of the first electrode uncoated portion in the longitudinal direction of the electrode.

4. The electrode of claim 1 , wherein the first protective tape covers the entire width of the electrode tab in the longitudinal direction of the electrode.

5. The electrode according to claim 1 , wherein the second protective tape is disposed in the second electrode uncoated portion so as to face the entire width of the electrode tab in the longitudinal direction of the electrode.

6. The electrode according to claim 1 , wherein the electrode current collector includes a third electrode non-coating portion extending from a second end opposite the first end in the longitudinal direction of the electrode.

7. 2. The electrode of claim 1, wherein a1 is 100% and b1 is 100%.

8. 2. The electrode of claim 1, wherein the first protective tape and the second protective tape are made of any one selected from the group consisting of polyethylene terephthalate (PET), polypropylene (PP), polyester, polycarbonate (PC), polyimide (PI), polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyarylate (PAR), polycylic olefin (PCO), polynorbornene (polynorbornene), polyethersulfone (PES), and cycloolefin polymer (COP).

9. The electrode according to claim 1 , wherein the first protective tape and the second protective tape each have a thickness of 10 μm or more and 100 μm or less.

10. a first electrode including a first electrode current collector; a separation membrane disposed on a surface of the first electrode; a second electrode comprising the electrode according to claim 1 and a second electrode current collector; the second electrode is disposed on a second surface of the separation membrane opposite a first surface of the separation membrane coupled to the first electrode; the first end of the second electrode is wound before the first electrode, and a jelly roll hollow portion is formed in a core portion.

11. 11. The jelly roll electrode assembly of claim 10, wherein the first end of the second electrode is located in the hollow portion of the jelly roll.

12. 11. The jelly roll electrode assembly of claim 10, wherein the first electrode is a positive electrode and the second electrode is a negative electrode.

13. the first electrode includes a positive electrode current collector; the positive electrode current collector includes a positive electrode ground portion that is coated with a positive electrode active material and a positive electrode uncoated portion that is not coated with the positive electrode active material, The jelly roll electrode assembly of claim 12 , wherein a positive electrode tab is disposed in the positive electrode uncoated portion.

14. the electrode tab of the second electrode is a negative electrode tab, 14. The jelly roll electrode assembly of claim 13, wherein the negative electrode tab extends across the width of the second electrode and the positive electrode tab extends across the width of the first electrode.

15. 14. The jelly roll electrode assembly of claim 13, wherein the positive electrode ground portion includes a first positive electrode ground portion coated on a first surface of the positive electrode current collector and a second positive electrode ground portion coated on a second surface opposite the first surface.

16. the electrode current collector of the second electrode is a negative electrode current collector, the negative electrode current collector includes a third electrode uncoated portion extending from a second end opposite the first end in the longitudinal direction of the second electrode, 13. The jelly roll electrode assembly of claim 12, wherein the third electrode uncoated portion is located at the outermost edge.

17. The separation membrane is a first separation membrane, 11. The jelly roll electrode assembly of claim 10, further comprising a second separator disposed on an opposite surface of the first electrode opposite the surface of the first electrode coupled to the first separator.

18. A battery exterior material; The jelly roll electrode assembly of claim 10 disposed within the battery housing; an exterior cap disposed at the opening of the battery exterior material.

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