Battery cell and rechargeable lithium battery including same

Abstract

The invention relates to a battery cell and a rechargeable lithium battery including the same. The battery cell includes: a wound electrode assembly including a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode; and an electrolyte immersed in the wound electrode assembly. The wound electrode assembly includes a pair of curved portions on opposite sides of the wound electrode assembly and a flat portion between the pair of curved portions. The electrolyte can include a non-aqueous organic solvent, a lithium salt, and an additive. The non-aqueous organic solvent comprises ethylene carbonate and ethyl propionate. The additive includes a compound represented by Chemical Formula 1. The ratio of the area of the negative electrode active material layer in the pair of curved portions to the total area of the negative electrode active material layer is 18%-50%. The volume ratio of the ethylene carbonate to the non-aqueous organic solvent is 20-50% by volume. The volume ratio of the ethyl propionate to the non-aqueous organic solvent is 50-80% by volume. Based on 100 parts by weight of the electrolyte, the amount of the additive is 1-10 parts by weight. Chemical formula 1

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0106672, filed on August 9, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] One or more embodiments of this disclosure relate to battery cells and rechargeable lithium batteries including battery cells. Background Technology

[0004] Recently, with the rapid growth and widespread adoption of battery-powered electronic devices (such as mobile phones, laptops, etc.) and / or electric vehicles, the demand for rechargeable lithium batteries with high energy density and high capacity (e.g., charge capacity) has increased rapidly. Therefore, a great deal of research and development has been conducted to improve or enhance the performance of rechargeable lithium batteries.

[0005] A rechargeable lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte. The positive and negative electrodes include active materials in which lithium ions can be inserted and extracted. If (for example, when) lithium ions are inserted and extracted, the rechargeable lithium-ion battery generates electrical energy through oxidation and reduction reactions.

[0006] Lithium salts dissolved in non-aqueous (e.g., water-insoluble) organic solvents are used as electrolytes in rechargeable lithium-ion batteries. The characteristics of rechargeable lithium-ion batteries can be exhibited through complex electrochemical reactions between the positive electrode and the electrolyte, and between the negative electrode and the electrolyte. Accordingly, the use of a suitable or appropriate electrolyte is one of the important variables for improving or enhancing the performance of rechargeable lithium-ion batteries. Summary of the Invention

[0007] One or more aspects of embodiments of this disclosure relate to battery cells with increased or enhanced energy density and reduced side reactions (or the degree or occurrence of side reactions) (e.g., battery cells with increased energy density and reduced (or decreased degree or occurrence of such reactions)).

[0008] One or more aspects of embodiments of this disclosure relate to pouch-type (or types of) rechargeable lithium batteries comprising individual battery cells.

[0009] Further aspects of the implementation will be set forth in part in the description which follows, and in part will be apparent from the description or may be learned by practicing the embodiments presented in this disclosure.

[0010] According to one or more embodiments of the present disclosure, a battery cell may include: a wound electrode assembly, wherein the wound electrode assembly includes a positive electrode, a negative electrode and a separator between the positive electrode and the negative electrode; and an electrolyte impregnated in / with the wound electrode assembly.

[0011] The negative electrode may include: a negative electrode current collector; a layer of negative electrode active material on at least one surface of the negative electrode current collector; and a negative electrode tab on an uncoated portion of the negative electrode current collector.

[0012] A wound electrode assembly may include: a pair of curved portions on two opposing (e.g., oppositely facing) sides of the wound electrode assembly; and a flat portion between the pair of curved portions.

[0013] The ratio of the area of ​​the negative electrode active material layer in a pair of curved portions to the total area of ​​the negative electrode active material layer can be in the range of about 18% to about 50%.

[0014] Electrolytes may include non-aqueous (e.g., water-insoluble) organic solvents, lithium salts, and additives.

[0015] Non-aqueous (e.g., water-insoluble) organic solvents may include ethylene carbonate and ethyl propionate.

[0016] The volume ratio of ethylene carbonate to a non-aqueous (e.g., water-insoluble) organic solvent can range from about 20% to about 50% by volume.

[0017] The volume ratio of ethyl propionate to a non-aqueous (e.g., water-insoluble) organic solvent can range from about 50% to about 80% by volume.

[0018] Additives may include compounds represented by chemical formula 1.

[0019] The amount of additive may be in the range of about 1 part by weight to about 10 parts by weight relative to (for example, based on) 100 parts by weight of electrolyte.

[0020] Chemical Formula 1

[0021]

[0022] In chemical formula 1,

[0023] X can be a halogroup (e.g., F, Cl, Br, or I) or a C1–C10 haloalkyl group.

[0024] m1 can be 1 or 2.

[0025] If (for example, when) m1 is 1, then m2 can be 2, and

[0026] If (for example, when) m1 is 2, then m2 can be 0.

[0027] According to one or more embodiments of this disclosure, a rechargeable lithium battery includes a battery cell as described in one or more embodiments; and a pouch-type (or type) housing that contains the battery cell. Attached Figure Description

[0028] The accompanying drawings, together with the specification, illustrate embodiments of the subject matter of this disclosure and, together with the description, serve to explain the principles of embodiments of the subject matter of this disclosure.

[0029] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure.

[0030] Figure 2 A simplified diagram illustrating a pouch-type (or type) rechargeable lithium battery according to one or more embodiments of the present disclosure.

[0031] Figure 3 A simplified diagram illustrating an unwound electrode assembly according to one or more embodiments of the present disclosure.

[0032] Figure 4 Detailed diagrams are provided to illustrate an unwound electrode assembly according to one or more embodiments of the present disclosure.

[0033] Figure 5 A simplified diagram illustrating a wound electrode assembly according to one or more embodiments of the present disclosure.

[0034] Figure 6 For along such Figure 5 The cross-sectional view of the wound electrode assembly taken along line A-A' as illustrated in the diagram.

[0035] Figure 7 A simplified one-way diagram illustrating a wound electrode assembly according to one or more embodiments of the present disclosure.

[0036] Figure 8 A simplified diagram illustrating an unwound negative electrode according to one or more embodiments of the present disclosure.

[0037] Figure 9 A simplified diagram illustrating a wound electrode assembly according to one or more embodiments of the present disclosure.

[0038] Figure 10 Based on the evaluation results of the evaluation examples.

[0039] Figure 11 A simplified diagram illustrating the stress distribution of the wound electrode assembly. Detailed Implementation

[0040] To fully understand the aspects and features of this disclosure, the subject matter will now be described in more detail with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the disclosed embodiments and may be implemented in one or more suitable forms. Rather, these embodiments are provided as examples with reference to the accompanying drawings to explain the aspects and features of this disclosure to those skilled in the art.

[0041] In this disclosure, it will be understood that if (for example, when) an element is referred to as being "on" another element, then the element may be directly on the other element, or there may be an intermediary element between the two. In contrast, if (for example, when) an element is referred to as being "directly on" another element, then there may be no intermediary element between the two.

[0042] In the accompanying drawings, the dimensions (e.g., thickness) of one or more components may be enlarged to effectively illustrate the technical content.

[0043] The same reference numerals refer to the same elements throughout the document, and their repeated descriptions are not required in this disclosure.

[0044] Unless otherwise stated in this disclosure, singular expressions may include plural expressions. Additionally, unless otherwise stated, the phrase “A or B” may indicate “A but not B,” “B but not A,” and “A and B.” The terms “includes / has” and / or “including / having” as used in this disclosure do not exclude the presence or addition of one or more other components.

[0045] As used herein, the term "combination of" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, reaction products, etc.

[0046] Unless otherwise specified in this disclosure, particle size may be the average particle size. Furthermore, particle size may refer to the average particle size (D) that constitutes approximately 50% by volume of the cumulative volume of the particle size distribution. 50 Average particle size (D) 50 The average particle size (D) can be measured by any suitable method commonly available or used by those skilled in the art (e.g., by a particle size analyzer), and / or may also be measured using transmission electron microscopy (TEM) images and / or scanning electron microscopy (SEM) images. Unless otherwise specified (e.g., when), the average particle size (D) as used herein refers to... 50The particle size distribution refers to the diameter of particles that constitute 50% of the total volume in a particle size distribution obtained by randomly measuring the size (e.g., diameter or major axis length) of approximately 20 particles in a scanning electron microscope (SEM) image. In one or more embodiments, a dynamic light scattering (DLS) measurement device can be used for data analysis, counting the number of particles in each particle size range, and then calculating the average particle size (D) from that data. 50 The laser scattering method can be used to measure the average particle size (D). 50 In laser scattering methods, target particles are dispersed in a dispersion solvent and introduced into a laser scattering particle size analyzer (e.g., MT3000 from Microtrac, Inc.). The particles are then irradiated with ultrasound at 28 kHz at a power of 60 W. The average particle size (D) is then calculated using this analyzer based on a 50% volume percentage particle size distribution. 50 In one or more embodiments, if (for example, when) the particles are spherical (e.g., substantially spherical), then “diameter” or “size” refers to the particle size, and if (for example, when) the particles are non-spherical, then “diameter” or “size” refers to the length of the major axis.

[0047] In this disclosure, the term "haloalkyl" may refer to an alkyl group in which one or more or all of the hydrogen atoms are replaced by halogen atoms.

[0048] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of this disclosure. (See reference...) Figure 1 A rechargeable lithium battery may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte ELL.

[0049] The positive electrode 10 and the negative electrode 20 may be spaced apart and / or separated from each other by a diaphragm 30 (e.g., spaced apart or separated). The diaphragm 30 may be between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the diaphragm 30 may be in contact with the electrolyte ELL. The positive electrode 10, the negative electrode 20, and the diaphragm 30 may be immersed in / impregnated with the electrolyte ELL.

[0050] The electrolyte ELL can serve as a medium for transporting lithium ions between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, lithium ions can migrate towards one of the positive electrode 10 and the negative electrode 20 through the separator 30.

[0051] Positive electrode 10

[0052] The positive electrode 10 for a rechargeable lithium battery may include a positive electrode current collector COL1 and a positive electrode active material layer AML1 on the positive electrode current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material and may further include a binder and / or a conductive (e.g., electrically conductive) material.

[0053] The amount of positive electrode active material may be from about 90 wt% to about 99 wt% relative to 100 wt% (e.g., based on a total of 100 wt%) of the positive electrode active material layer AML1. The amount of each of the binder and the conductive (e.g., electrically conductive) material may be from about 0.5 wt% to about 5 wt% relative to 100 wt% (e.g., based on a total of 100 wt%) of the positive electrode active material layer AML1.

[0054] The binder can be used to improve or enhance the adhesion between the positive electrode active material particles and also to improve or enhance the adhesion between the positive electrode active material and the positive electrode current collector COL1. The binder may include, for example, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, and / or nylon, but embodiments of this disclosure are not limited thereto.

[0055] Conductive (e.g., electrically conductive) materials can be used to provide electrode conductivity (e.g., electrical conductivity), and as conductive (e.g., electrically conductive) materials, any suitable conductive (e.g., electrically conductive) material that will not cause chemical changes (e.g., undesirable chemical changes) in a rechargeable lithium battery can be used. For example, conductive (e.g., electrically conductive) materials may include: carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes); metal powders and / or metal fibers containing one or more of copper, nickel, aluminum, and silver; conductive (e.g., electrically conductive) polymers (such as polyphenylene and polyphenylene derivatives); and / or mixtures thereof (e.g., any suitable mixture thereof).

[0056] Aluminum (Al) foil can be used as the positive electrode current collector COL1, but the embodiments of this disclosure are not limited thereto.

[0057] Positive electrode active material

[0058] The positive electrode active material in the positive electrode active material layer AML1 may include compounds that can reversibly insert and extract lithium (e.g., lithiated intercalation compounds). For example, the positive electrode active material may include at least one type of composite oxide comprising lithium, and the composite oxide may also include metals selected from cobalt, manganese, nickel and / or combinations thereof (e.g., any suitable combination thereof).

[0059] Composite oxides may include lithium transition metal composite oxides, such as lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel manganese oxides and / or combinations thereof (e.g., any suitable combination thereof).

[0060] For example, the positive electrode active material may include a compound represented by one of the chemical formulas. Li a A 1-b X b O 2-c D c (where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni b Co c L 1 d G e O2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0 ≤ e ≤ 0.1); Li a NiG b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a CoG bO2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-b G b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-g G g PO4 (where 0.90 ≤ a ≤ 1.8 and 0 ≤ g ≤ 0.5); Li (3-f) Fe2(PO4)3 (where 0 ≤ f ≤ 2); and Li a FePO4 (where 0.90≤a≤1.8).

[0061] In the aforementioned chemical formula, A may be nickel (Ni), cobalt (Co), manganese (Mn) and / or combinations thereof (e.g., any suitable combination thereof), X may be aluminum (Al), Ni, Co, Mn, chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), rare earth elements and / or combinations thereof (e.g., any suitable combination thereof), D may be oxygen (O), fluorine (F), sulfur (S), phosphorus (P) and / or combinations thereof (e.g., any suitable combination thereof), G may be Al, Cr, Mn, Fe, Mg, lanthanum (La), cerium (Ce), Sr, V, and / or combinations thereof (e.g., any suitable combination thereof), and L 1 It can be Mn, Al and / or combinations thereof (e.g., any suitable combination thereof).

[0062] For example, relative to 100 mol% of lithium-free metal in a lithium transition metal complex oxide (e.g., based on), the positive electrode active material can be a high-nickel positive electrode active material with a nickel content equal to or greater than about 80 mol%, equal to or greater than about 85 mol%, equal to or greater than about 90 mol%, equal to or greater than about 91 mol%, or equal to or greater than about 94 mol% and equal to or less than about 99 mol%. High-nickel positive electrode active materials can achieve or provide high capacity (e.g., electrical capacity), and therefore can be used in high-capacity (e.g., high electrical capacity) and high-density rechargeable lithium batteries.

[0063] negative electrode 20

[0064] The negative electrode 20 for a rechargeable lithium battery may include a negative electrode current collector COL2 and a negative electrode active material layer AML2 on the negative electrode current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material and may further include a binder and / or a conductive (e.g., electrically conductive) material.

[0065] For example, relative to 100 wt% of the negative electrode active material layer AML2, the negative electrode active material layer AML2 may include about 90 wt% to about 99.5 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0 wt% to about 5 wt% of the conductive (e.g., electrically conductive) material.

[0066] The binder can be used to improve or enhance the adhesion between the negative electrode active material particles and also to improve or enhance the adhesion between the negative electrode active material and the negative electrode current collector COL2. The binder may include non-aqueous (e.g., water-insoluble) binders, aqueous (e.g., water-soluble) binders, dry binders and / or combinations thereof (e.g., any suitable combination thereof).

[0067] Non-aqueous (e.g., water-insoluble) adhesives may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide and / or combinations thereof (e.g., any suitable combination thereof).

[0068] Waterborne (e.g., water-soluble) adhesives may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomers, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resins, (meth)acrylic resins, phenolic resins, epoxy resins, polyvinyl alcohol, and / or combinations thereof (e.g., any suitable combination thereof).

[0069] If, for example, an aqueous (e.g., water-soluble) binder is used as a binder in the negative electrode active material layer AML2, a cellulose compound capable of providing or increasing viscosity may be further included as a thickener. The cellulose compound may include one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts. The alkali metal may include sodium (Na), potassium (K), and / or lithium (Li).

[0070] Dry adhesives may include fibrous polymeric materials, such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide and / or combinations thereof (e.g., any suitable combination thereof).

[0071] Conductive (e.g., electrically conductive) materials (e.g., electronic conductors) can be used to provide electrode conductivity (e.g., electrical conductivity), and as conductive (e.g., electrically conductive) materials, any suitable conductive (e.g., electrically conductive) material that will not cause chemical changes (e.g., undesirable chemical changes) in a rechargeable lithium battery can be used. For example, conductive (e.g., electrically conductive) materials may include: carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes); metal powders and / or metal fibers including one or more selected from copper, nickel, aluminum, and silver; conductive (e.g., electrically conductive) polymers (such as polyphenylene and polyphenylene derivatives); and / or mixtures thereof (e.g., any suitable mixture thereof).

[0072] The negative electrode current collector COL2 may include copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive (e.g., electrically conductive) metal, and / or combinations thereof (e.g., any suitable combination thereof).

[0073] Negative electrode active material

[0074] The negative electrode active material in the negative electrode active material layer AML2 may include materials that can reversibly insert and deintercalate lithium ions, lithium metal, lithium metal alloys, materials that can be doped and dedoped with lithium, and / or transition metal oxides.

[0075] Materials capable of reversibly inserting and deintercalating lithium ions may include carbon-based negative electrode active materials, such as crystalline carbon, amorphous (e.g., non-crystalline) carbon, and / or combinations thereof (e.g., any suitable combination thereof). For example, crystalline carbon may include graphite, such as amorphous (e.g., substantially amorphous), flake-like (e.g., substantially flake-like), sheet-like (e.g., substantially sheet-like), spherical (e.g., substantially spherical), or fibrous (e.g., substantially fibrous) natural graphite and / or artificial graphite, and amorphous (e.g., non-crystalline) carbon may include soft carbon, hard carbon, mesophase pitch carbides, and / or calcined coke.

[0076] Lithium metal alloys may include alloys of lithium and metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0077] Materials that can be doped and dedoped with lithium can include Si-based negative electrode active materials and / or Sn-based negative electrode active materials. Si-based negative electrode active materials can include silicon, silicon-carbon composites, and SiO₂. x(where 0 < x ≤ 2), Si-Q alloy (where Q can be an alkali metal, alkaline earth metal, Group 13 element, Group 14 element (excluding Si), Group 15 element, Group 16 element, transition metal, rare earth element, and / or a combination thereof (e.g., any suitable combination thereof)) and / or a combination thereof (e.g., any suitable combination thereof). The Sn-based negative electrode active material may include Sn, SnO x (where 0 < x ≤ 2; for example, SnO2), Sn-based alloys, and combinations thereof (e.g., any suitable combination thereof).

[0078] The silicon-carbon composite may be a composite of silicon and amorphous (e.g., non-crystalline) carbon. According to one or more embodiments, the silicon-carbon composite may have a structure in which amorphous (e.g., non-crystalline) carbon is coated on the surface of silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are concentrated and an amorphous (e.g., non-crystalline) carbon coating (shell) on the surface of the secondary particles. Amorphous (e.g., non-crystalline) carbon may also be between the primary silicon particles, and for example, the primary silicon particles may be coated with amorphous (e.g., non-crystalline) carbon. The secondary particles may be dispersed in an amorphous (e.g., non-crystalline) carbon matrix.

[0079] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core including crystalline carbon and silicon particles, and may also include an amorphous (e.g., non-crystalline) carbon coating on the surface of the core.

[0080] The Si-based negative electrode active material and / or the Sn-based negative electrode active material may be used in combination with a carbon-based negative electrode active material.

[0081] Separator 30

[0082] Depending on the type (or kind) of the rechargeable lithium battery, the separator 30 may be between the positive electrode 10 and the negative electrode 20. The separator 30 may include one or more selected from a polyethylene separator, a polypropylene separator, and a polyvinylidene fluoride separator, and may have a multilayer separator, such as a polyethylene / polypropylene bilayer separator, a polyethylene / polypropylene / polyethylene trilayer separator, and / or a polypropylene / polyethylene / polypropylene trilayer separator.

[0083] The separator 30 may include a porous substrate and a coating on the side or surface (e.g., one surface or two surfaces (e.g., two opposite (facing) surfaces)) of the porous substrate, the coating including an organic material, an inorganic material, and / or a combination thereof (e.g., any suitable combination thereof).

[0084] The porous substrate may be a polymer layer comprising one selected from: polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, and polytetrafluoroethylene (Teflon). TM Alternatively, the polymer layer may comprise a copolymer or (e.g., any suitable) mixture containing two or more of the materials mentioned above.

[0085] Organic materials may include polyvinylidene fluoride copolymers and / or (meth)acrylic acid copolymers.

[0086] Inorganic materials may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and / or combinations thereof (e.g., any suitable combination thereof), but embodiments of this disclosure are not limited thereto.

[0087] Organic and inorganic materials can be mixed in a single coating, or they can exist in a stacked form of a coating that includes organic materials and a coating that includes inorganic materials.

[0088] Electrolyte ELL

[0089] Electrolytes (ELLs) used in rechargeable lithium batteries may include non-aqueous (e.g., water-insoluble) organic solvents and lithium salts.

[0090] Non-aqueous (e.g., water-insoluble) organic solvents can be used as a medium for transporting ions that participate in the electrochemical reactions in rechargeable lithium batteries.

[0091] Non-aqueous (e.g., water-insoluble) organic solvents may include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents and / or combinations thereof (e.g., any suitable combination thereof).

[0092] Carbonate 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), and / or butyl carbonate (BC).

[0093] Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, caprolactone, and / or propyl propionate (PP).

[0094] Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and / or tetrahydrofuran. Ketone solvents may include cyclohexanone. Alcohol solvents may include ethanol and / or isopropanol. Aprotic solvents may include nitriles (such as R-CN, where R may be a hydrocarbon group having a C2-C20 straight-chain, branched, or cyclic structure, and may include double bonds, aromatic rings, and / or ether bonds); amides (such as dimethylformamide); dioxolane (such as 1,3-dioxolane or 1,4-dioxolane); and / or sulfolane.

[0095] Non-aqueous (e.g., water-insoluble) organic solvents can be used alone or in mixtures of two or more substances.

[0096] In one or more embodiments, if (for example, when) a carbonate solvent is used, cyclic carbonates and chain carbonates can be mixed and used, and cyclic carbonates and chain carbonates can be mixed in a volume ratio of about 1:1 to about 1:9.

[0097] Lithium salts can be materials dissolved in non-aqueous (e.g., water-insoluble) organic solvents to serve as a source of lithium ions for use in rechargeable lithium batteries, and play a role in ensuring the basic operation of rechargeable lithium batteries and facilitating the movement of lithium ions between the positive and negative electrodes. Lithium salts may include, for example, those selected from 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 SO2 (where x and y can be integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0098] The electrolyte of a battery cell according to one or more embodiments of the present disclosure will be described in more detail below.

[0099] The electrolyte according to one or more embodiments may include a non-aqueous (e.g., water-insoluble) organic solvent, a lithium salt, and additives.

[0100] Electrolytes can be prepared by a mixing process in which lithium salts are dissolved in a non-aqueous (e.g., water-insoluble) organic solvent and additives are added for mixing. Electrolyte mixing processes are commonly available or used in the field of electrolyte manufacturing, and those skilled in the art will be able to select and use them appropriately.

[0101] The electrolyte according to one or more embodiments of this disclosure may have a relatively high ionic conductivity (e.g., be an ionic conductor). Non-aqueous (e.g., water-insoluble) organic solvents, lithium salts, and additives may be adjusted to have an optimal composition to prepare an electrolyte with relatively high lithium-ion conductivity (e.g., ionic conductivity). In one or more embodiments, the ionic conductivity of the electrolyte may be in the range of about 7.2 mS / cm to about 7.7 mS / cm.

[0102] In one or more embodiments, the non-aqueous (e.g., water-insoluble) organic solvent may include one or more selected from carbonate solvents and propionate solvents.

[0103] In one or more embodiments, the non-aqueous (e.g., water-insoluble) organic solvent may include ethylene carbonate (EC) and ethyl propionate (EP).

[0104] The volume ratio of ethylene carbonate (EC) to a non-aqueous (e.g., water-insoluble) organic solvent can range from about 20 vol% to about 50 vol%. Ethylene carbonate (EC) can dissociate lithium salts in the electrolyte to be used as or for replenishing lithium ions. For example, ethylene carbonate (EC) can dissociate LiPF6 lithium salts into Li... + and PF6 - The dissociated lithium ions can be used as a lithium-ion source in rechargeable lithium batteries, thus allowing the rechargeable lithium batteries to have increased or enhanced ionic conductivity. Since ethylene carbonate (EC) is a high-viscosity organic solvent, exceeding the aforementioned volume range may lead to an increase in side reactions (e.g., undesirable side reactions).

[0105] The volume ratio of ethyl propionate (EP) to a non-aqueous (e.g., water-insoluble) organic solvent can range from about 50 vol% to about 80 vol%. Ethyl propionate (EP) can be used as a solvent or to improve or enhance impregnation properties and increase conductivity. Due to the relatively high melting point of ethylene carbonate (EC), excessive use can reduce the ionic conductivity of the electrolyte at low temperatures. A set or predetermined volume of ethyl propionate (EP) with excellent or suitable impregnation properties and relatively high ionic conductivity can be mixed to mitigate the disadvantages of ethylene carbonate (EC) and allow the electrolyte to maintain its high ionic conductivity even at low temperatures. Low temperature can refer to a temperature equal to or less than about 40°C, equal to or less than about 35°C, equal to or less than about 30°C, or equal to or less than about 15°C.

[0106] In one or more embodiments, the non-aqueous (e.g., water-insoluble) organic solvent may include ethylene carbonate (EC), propylene carbonate (PC), and ethyl propionate (EP).

[0107] In one or more embodiments, the non-aqueous (e.g., water-insoluble) organic solvent may include ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP), and propyl propionate (PP).

[0108] In one or more embodiments, the volume ratio of PC to a non-aqueous organic solvent can range from 5% to 15% by volume. The volume ratio of PP to a non-aqueous organic solvent can also range from 5% to 15% by volume.

[0109] In one or more embodiments, the lithium salt may include those selected from 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 SO2 (where x and y can be integers from 1 to 20), and at least one of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0110] In one or more embodiments, the lithium salt may include LiPF6.

[0111] The lithium salt can have a concentration of about 0.1 M to about 2.0 M. For example, the lithium salt can have a concentration equal to or greater than about 1.0 M, equal to or greater than about 1.4 M, or equal to or greater than about 1.5 M. The lithium salt can have a concentration equal to or less than about 2.0 M, equal to or less than about 1.8 M, or equal to or less than about 1.6 M. If (for example, when) the concentration of the lithium salt falls within the aforementioned range, the electrolyte can maintain a suitable or appropriate viscosity and have excellent or appropriate ionic conductivity.

[0112] In one or more embodiments, the additive according to this disclosure may be a compound represented by chemical formula 1.

[0113] Chemical Formula 1

[0114]

[0115] In chemical formula 1,

[0116] X can be a halogen (e.g., F, Cl, Br or I) or a C1 to C10 haloalkyl group.

[0117] m1 can be 1 or 2.

[0118] If (for example, when) m1 is 1, then m2 can be 2.

[0119] If (for example, when) m1 is 2, then m2 can be 0.

[0120] In one or more embodiments, the additive may include lithium difluoro(oxalate)borate (LiDFOB). The additive may have the function of forming a passivation layer on the negative electrode, thereby reducing (or reducing the extent or occurrence of) side reactions at the interface between the negative electrode and the electrolyte.

[0121] In one or more embodiments, the additive may be lithium bis(oxalate)borate (LiBOB).

[0122] The amount of additive relative to (e.g., based on) 100 parts by weight of electrolyte can be about 1 part by weight to about 10 parts by weight. In one or more embodiments, the amount of additive can be in the range of about 1 part by weight to about 5 parts by weight. In one or more embodiments, the amount of additive can be in the range of about 1 part by weight to about 3 parts by weight. If (e.g., when) the amount of additive is greater than the aforementioned range, the additive may induce excessive resistance, and therefore the electrolyte may have reduced ionic conductivity. On the other hand, if the amount of additive is less than the aforementioned range, the amount of additive may be too small to effectively reduce the side reactions (or the degree or occurrence of side reactions) occurring at the interface between the negative electrode and the electrolyte.

[0123] battery cell

[0124] Reference Figures 3-9 A battery cell according to one or more embodiments of the present disclosure is described in more detail. A battery cell according to one or more embodiments of the present disclosure may include a wound electrode assembly and an electrolyte. The wound electrode assembly may include a positive electrode, a negative electrode, and a separator between the positive and negative electrodes.

[0125] refer to Figures 3-5 The wound electrode assembly can be provided in such a way that the positive electrode 10, the diaphragm 30, and the negative electrode 20 can be stacked and wound around a winding axis AXS, and then along a direction perpendicular to (e.g., substantially perpendicular to) a relatively flat plane (e.g., along as in...). Figure 3 (The direction opposite to axis D1) is suppressed as explained in the middle.

[0126] Figure 3This is a simplified diagram illustrating an unwound electrode assembly according to one or more embodiments of the present disclosure. The stacking order of the positive electrode 10 and the negative electrode 20 can be interchanged. For example, the negative electrode 20, the diaphragm 30, and the positive electrode 10 can be stacked in the aforementioned order.

[0127] Figure 4 Detailed diagrams illustrating an unwound electrode assembly according to one or more embodiments of this disclosure are provided. (See also:) Figure 4 The negative electrode 20 may include a negative electrode current collector COL2, a negative electrode active material layer AML2, and a negative electrode terminal block TAB2. The negative electrode active material layer AML2 may be on at least one surface of the negative electrode current collector COL2. For example, the negative electrode active material layer AML2 may be on one or both surfaces of the negative electrode current collector COL2 (e.g., two opposing (facing) surfaces). Figure 4 The negative electrode tab TAB2 may be on the uncoated portion of the negative electrode current collector COL2. The uncoated portion indicates the portion where the negative electrode active material layer AML2 is not on the negative electrode current collector COL2. One or more negative electrode tabs TAB2 may be formed or provided. For example, two negative electrode tabs TAB2 may be provided (e.g., as shown in the image). Figure 4 (TAB2a and TAB2b in the text).

[0128] The positive electrode 10 may include a positive electrode current collector COL1, a positive electrode active material layer AML1, and a positive electrode terminal block TAB1. The positive electrode active material layer AML1 may be present on at least one surface of the positive electrode current collector COL1. For example, the positive electrode active material layer AML1 may be present on the surface of the positive electrode current collector COL1 (e.g., one surface or two surfaces (e.g., two opposing (facing) surfaces)). Figure 4 The positive electrode tab TAB1 may be on the uncoated portion of the positive electrode current collector COL1. The uncoated portion indicates the portion where the positive electrode active material layer AML1 is not on the positive electrode current collector COL1. One or more positive electrode tabs TAB1 may be formed or provided. For example, two positive electrode tabs TAB1 may be provided (e.g., as shown in the image). Figure 4 (TAB1a and TAB1b in the text).

[0129] The diaphragm 30 may be located between the positive electrode 10 and the negative electrode 20. If needed or desired, the diaphragm 30 may be additionally stacked at the bottom. For example, the diaphragm 30, the positive electrode 10, the diaphragm 30, and the negative electrode 20 may be stacked in the aforementioned order.

[0130] exist Figure 4In this embodiment, the negative electrode current collector COL2 may be longer than the positive electrode current collector COL1 in the width direction (e.g., in a direction parallel (e.g., substantially parallel) to axis D2). In one or more embodiments, the negative electrode active material layer AML2 may be longer than the positive electrode active material layer AML1 in the width direction. In one or more embodiments, the lengths of the separator 30, the positive electrode current collector COL1, and the negative electrode current collector COL2 may differ from each other in the width direction. For example, to prevent or reduce the formation of lithium dendrites, the negative electrode active material layer AML2 may be longer than the positive electrode active material layer AML1.

[0131] Figure 5 A simplified diagram illustrating a wound electrode assembly according to one or more embodiments of the present disclosure. References Figure 5 The wound electrode assembly may include a flat portion FLT and a pair of curved portions RND. Compared to the flat portion FLT, the pair of curved portions RND may have a relatively circular (e.g., substantially circular) shape on their outer surfaces. The pair of curved portions RND may be located or provided on two opposing (e.g., oppositely facing) sides of the wound electrode assembly (see RND1 and RND2). The flat portion FLT may be located between the pair of curved portions RND.

[0132] Figure 6 For along Figure 5 The image shows a cross-sectional view taken along line A-A' of the wound electrode assembly. Line A-A' can be any straight line parallel (e.g., substantially parallel) to the width direction of the wound electrode assembly (e.g., the direction of axis D2). A pair of curved portions RND can refer to two parts of the wound electrode assembly, in each part having an outer surface of approximately 1m... -1 ~ Approximately 1000m -1 The curvature. The flat portion FLT can refer to the portion of the wound electrode assembly other than the pair of curved portions RND in the wound electrode assembly.

[0133] In this specification, the term "curvature" refers to the geometric parameter used to distinguish between the curved portion (RND) and the flat portion (FLT) of the cross-section of a core-type electrode assembly, such as... Figure 6 As shown in the diagram, the curved portion RND corresponds to the circular portions located at both ends of the elliptical outer periphery of the wound electrode assembly, and includes the curvature of the outer peripheral surface falling into approximately 1m. -1 ~1000m -1 The area within the range.

[0134] According to the relation κ = 1 / R, curvature is defined based on the radius (R) of the outer surface. In this specification, regions with curvature within the above range are considered curved portions RND, while the remaining regions are defined as flat portions FLT.

[0135] Curvature is calculated by measuring the bending profile of the outer surface of the cross-section (in the A-A' direction) of the electrode assembly under wound and compressed conditions. The radius of curvature (R) can be measured using, for example, a non-contact laser profilometer or an optical measuring device (e.g., a 3D shape measuring instrument), and the measured value is used to calculate the curvature κ = 1 / R. Reference Figure 7 The width W of a pair of curved sections RND RND Width W of the wound electrode assembly ASB The ratio can range from approximately 5% to approximately 50%. The width W of a pair of curved portions RND RND It can be the sum of the widths (W) of the curved portions RND on two opposite (e.g., facing opposite) sides. RND1 +W RND2 ).

[0136] Increasing energy density may require increasing the proportion of the pair of curved RND portions in the wound electrode assembly. In a single cell according to one or more embodiments of the present disclosure, the ratio of the area of ​​the negative electrode active material layer in the pair of curved portions to the total area of ​​the negative electrode active material layer may be in the range of about 18% to about 50%. In one or more embodiments, this ratio may be in the range of about 19% to about 40%. In one or more embodiments, this ratio may be in the range of about 19% to about 30%.

[0137] For example, the width of the curved portion (W) RND ) and the width (W) of the wound electrode assembly ASB The ratio of W can range from approximately 5% to 50%, where W RND The sum of the widths of the curved portions on two opposite (e.g., facing opposite) sides (W) RND1 +W RND2 Increasing energy density may require a higher proportion of these curved sections. In disclosed battery cells, the ratio of the area of ​​the negative electrode active material layer in the curved section to the total area of ​​the negative electrode active material layer can range from about 18% to about 50%, with some embodiments ranging from about 19% to about 40% or from about 19% to about 30%. Here, the ratio is expressed as a percentage to provide a clear, standardized comparative measurement, thereby making it easier to understand and interpret the degree of improvement or difference. More specifically, the width ratio is calculated as follows: W RND Divide by W ASBThe area ratio is calculated by dividing the area of ​​the negative electrode active material layer in the bend by the total area of ​​the negative electrode active material layer, and then multiplying by 100 to convert it to a percentage. This ratio indicates the proportion of the area of ​​the active material layer in the bend relative to the total area of ​​the total active material layer.

[0138] refer to Figures 6-9 The total area of ​​the active material layer of the negative electrode can be calculated according to Equation 1.

[0139] Equation 1

[0140] The total area of ​​the negative electrode active material layer = the width W of the negative electrode active material layer AML2 ×Length of the negative electrode active material layer L AML2

[0141] The area of ​​the negative electrode active material layer in a pair of curved sections can be calculated according to Equation 2. The length L of the wound electrode assembly... ASB The length L of the negative electrode active material layer can be adjusted. AML2 They are essentially the same. The number of turns refers to the number of times the negative electrode active material is wound during the winding process. For example, the number of turns could be 3, such as... Figure 6 The explanation is as follows.

[0142] Equation 2

[0143] The area of ​​the negative electrode active material layer in a pair of curved sections =

[0144] Total area of ​​negative electrode active material layer – Total area of ​​negative electrode active material in flat portion =

[0145] Width W of the negative electrode active material layer AML2 ×Length of the negative electrode active material layer L AML2}–{[width W of the flat portion] FLT ×Length of the wound electrode assembly L ASB [×Number of turns] – [Width W of the uncoated portion of the negative electrode current collector in the flat section] UCT ×Length of the wound electrode assembly L ASB ]}

[0146] refer to Figure 11 (A) A reduction in the ratio of a pair of bent portions can lead to a decrease in energy density, but may generate weak stress (low pressure) within the wound electrode assembly. Reference Figure 11In (B), an increase in the ratio of a pair of bent portions can lead to an increase in energy density, but strong stress (high pressure, see P) may be generated inside the wound electrode assembly. Under such stress, since the charging / discharging of the battery may not proceed smoothly and side reactions may increase, the increase in the ratio of the bent portions may be limited. The battery according to one or more embodiments of the present disclosure may include an electrolyte that is improved or optimized to suppress or reduce side reactions (or the degree or occurrence of side reactions) of a rechargeable lithium battery, and thus side reactions (or the degree or occurrence of side reactions) can be minimized or reduced even if (for example, when) the battery cell has a structure in which the ratio of the bent portions is large. Therefore, a high energy density can be achieved or provided.

[0147] The battery cell according to one or more embodiments of the present disclosure may have a high mixture density of the negative electrode active material layer AML2. In one or more embodiments, the mixture density may be from about 1.0 g / cc to about 10 g / cc. In one or more embodiments, the mixture density may be from about 1.65 g / cc to about 4.00 g / cc. The high mixture density can enable the rechargeable lithium battery to have a relatively high energy density.

[0148] The positive electrode active material layer AML1 may include a lithium composite oxide represented by Chemical Formula 2.

[0149] Chemical Formula 2 <00004​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The negative electrode active material layer AML2 may include carbon-based negative electrode active materials, Si-based negative electrode active materials, Sn-based negative electrode active materials and / or combinations thereof (e.g., any suitable combination thereof).

[0155] The battery cells according to one or more embodiments of this disclosure can exhibit excellent or adequate performance even at relatively high voltages. High voltages may be equal to or greater than about 3.0V, equal to or greater than about 3.5V, equal to or greater than about 4.0V, or equal to or greater than about 4.47V.

[0156] Battery cells according to one or more embodiments of this disclosure can be used when housed in one or more housings of different shapes. For example, the housing may be cylindrical, prismatic, pouch-shaped (or similar), or any other suitable shape. If, for example, the battery cell is housed in a pouch-shaped (or similar) housing, it may be referred to as a pouch-shaped (or similar) rechargeable lithium battery. One or more structures may be added to suit the appearance of the housing. For example, refer to… Figure 2 Electrode terminal 70 can be added separately and connected to the positive electrode terminal (see...). Figure 4 TAB1) and negative electrode terminal (see Figure 4 (TAB2).

[0157] The battery cells according to one or more embodiments of this disclosure can be applied to motor vehicles, mobile phones and / or any other electrical devices, but the embodiments of this disclosure are not limited thereto.

[0158] refer to Figure 2 According to one embodiment of the present invention, the rechargeable lithium battery 100 may be a pouch-type battery. The pouch-type rechargeable lithium battery 100 may include a casing 50, electrode terminals 70, an electrode assembly 40, a positive electrode 10, a negative electrode 20, and a separator 30. The electrode terminals 70 can be connected to the positive electrode terminals (see...). Figure 4 (TAB1) and negative electrode terminal (see Figure 4 (TAB2).

[0159] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to implementation methods and comparative examples. However, the following examples are merely examples of the present disclosure, and embodiments of the present disclosure are not limited to the following examples.

[0160] Implementation methods and comparative examples

[0161] Implementation Method 1

[0162] (1) Preparation of electrolyte

[0163] LiPF6 was dissolved in a non-aqueous (e.g., water-insoluble) organic solvent containing a mixture of ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP), and propyl propionate (PP). A compound including lithium difluoro(oxalate)borate (LiDFOB) was added (based on 100 parts by weight of the electrolyte) to prepare the electrolyte.

[0164] (2) Manufacturing of battery cells

[0165] LiCoO2 as the positive electrode active material, polyvinylidene fluoride as the binder, and Ketjenblack as the conductive (e.g., electrically conductive) material were mixed in a weight ratio of 97:2:1, and the mixture was dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0166] The positive electrode active material slurry was coated onto an aluminum current collector with a thickness of 14 μm, dried at 110 °C, and then pressed to manufacture the positive electrode.

[0167] Artificial graphite and silicon nanoparticles, used as negative electrode active materials, were mixed in a weight ratio of 93:7; styrene-butadiene rubber (SBR), used as a binder; and carboxymethyl cellulose (CMC), used as a tackifier, were mixed in a weight ratio of 97:1:2. The mixture was then dispersed in distilled water to prepare a negative electrode active material slurry.

[0168] A slurry of negative electrode active material was coated onto a 10 μm thick copper current collector, dried at 100 °C, and then pressed to fabricate the negative electrode. The mixture density of the negative electrode active material layer was 1.65 g / cc.

[0169] The positive electrode, negative electrode, and a 10 μm thick polyethylene separator are wound together and then pressed to manufacture a wound electrode assembly. The electrolyte described above is then injected to manufacture a battery cell.

[0170] Table 1 lists the characteristics of the wound electrode assembly and the composition of the electrolyte.

[0171] Implementation Methods 2 to 5

[0172] Preparation / Performance of Embodiments 2 to 5. In each of Embodiments 2 to 5, the electrolyte and battery cell are manufactured in essentially the same manner as in Embodiment 1, except that the characteristics of the wound electrode assembly and the composition of the electrolyte differ. Table 1 lists the characteristics of the wound electrode assembly and the composition of the electrolyte for each of Embodiments 2 to 5.

[0173] Comparative Examples 1 to 5

[0174] Preparation / Comparative Examples 1 to 5 were conducted. In each of Comparative Examples 1 to 5, the electrolyte and battery cell were manufactured in essentially the same manner as in Embodiment 1, except that the characteristics of the wound electrode assembly and the composition of the electrolyte differed. Table 1 lists the characteristics of the wound electrode assembly and the composition of the electrolyte for each of Comparative Examples 1 to 5.

[0175] Assessment 1: Low-Temperature Cycling Life

[0176] The battery cells of each of the embodiments and comparative examples are housed in a pouch-type (or similar) battery casing to manufacture a pouch-type (or similar) rechargeable lithium battery. The rechargeable lithium battery is charged at 25°C, 0.2C, 4.47V, and a 0.02C cutoff condition, and then initially discharged at 25°C, 1C, and a 3.0V cutoff condition, and the initial discharge capacity of the rechargeable lithium battery is measured. 50 charge / discharge cycles are performed, and the discharge capacity after 50 cycles is measured. Charging conditions are 15°C, 2C, 4.47V, and a 0.1C cutoff condition. Discharging conditions are 15°C, 1C, and a 3.0V cutoff condition. The capacity retention rate is calculated according to Equation 3.

[0177] Equation 3

[0178] Capacity retention (%) = (Discharge capacity after 50 cycles / Initial discharge capacity) × 100

[0179] Assessment 2: Side effects after low-temperature cycling life

[0180] The battery cells of each of the embodiments and comparative examples were housed in a pouch-type (or similar) battery casing to manufacture a pouch-type (or similar) rechargeable lithium battery. After a low-temperature cycle life assessment according to Evaluation 1, the rechargeable lithium battery was disassembled to determine the extent of side reactions occurring at the negative electrode. A score of 0 was given for cases with no side reactions, and a score of 5 was given for cases with severe side reactions. It was confirmed that the rechargeable lithium batteries of Comparative Examples 2 to 5 exhibited side reactions and discoloration. The results are shown in Table 2 and... Figure 10 The explanation is as follows.

[0181] Table 1

[0182]

[0183] *A: The proportion of the curved portion of the negative electrode = the ratio of the area of ​​the negative electrode active material layer in a pair of curved portions to the total area of ​​the negative electrode active material layer.

[0184] *B: The mixture density of the negative electrode = the mixture density of the active material layer of the negative electrode.

[0185] Table 2

[0186]

[0187]

[0188] Referring to Tables 1 and 2, it can be determined that the low-temperature cycle life assessment and side reaction assessment according to the embodiments of the present disclosure are superior or appropriate compared to the comparative examples. For example, it can be confirmed that although the battery cells according to the present disclosure have high energy density, they also exhibit superior or appropriate performance due to the minimal occurrence of side reactions.

[0189] A single cell according to one or more embodiments of this disclosure may have high energy density and minimal side reactions.

[0190] Rechargeable lithium batteries according to one or more embodiments of this disclosure may have high energy density and minimal side reactions.

[0191] In summary, compared to comparative examples, the battery cells described in this disclosure exhibit superior low-temperature cycle life and reduced side reactions. Despite their high energy density, the battery cells also maintain excellent performance and minimal side reactions, making them ideal for use. This applies to conventional battery cells and rechargeable lithium batteries according to the disclosed embodiments.

[0192] Battery manufacturing apparatus, battery management system (BMS) apparatus, and / or any other related apparatus or component according to one or more embodiments of this disclosure may be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuit), software, or a combination of software, firmware, and hardware (e.g., any suitable combination). For example, one or more suitable components of the apparatus may be provided on an integrated circuit (IC) chip or on a separate IC chip. Furthermore, one or more suitable components of the apparatus may be implemented on a flexible printed circuit film, tape-on-a-carrier package (TCP), or printed circuit board (PCB), or provided on a substrate. Additionally, one or more suitable components of the apparatus may be a process or thread that runs on one or more processors in one or more computing devices, executes computer program instructions, and interacts with other system components to perform one or more suitable functions described herein. The computer program instructions are stored in memory, which may be implemented in the computing device using standard memory devices (such as random access memory (RAM) for example). The computer program instructions may also be stored in other non-transitory computer-readable media (such as CD-ROMs, flash drives, etc. for example). Furthermore, those skilled in the art will recognize that, without departing from the scope of this disclosure, the functions of one or more suitable computing devices may be combined or integrated into a single computing device, or the functions of a dedicated computing device may be distributed across one or more other computing devices.

[0193] Based on the entirety of this disclosure, those skilled in the art will recognize that each suitable feature of one or more embodiments of this disclosure may be combined in part or in whole, or combined with one another, and may be technically interlocked and operated in one or more suitable ways, and that each embodiment may be implemented independently of one another or in combination with one another in any suitable way, unless otherwise stated or implied.

[0194] Although the subject matter of this disclosure has been described in conjunction with embodiments now considered practical, it should be understood that this disclosure is not limited to the disclosed embodiments. Instead, it is intended to cover one or more suitable modifications and equivalent arrangements encompassed within the spirit and scope of the claims and their equivalents. Therefore, it will be understood that the foregoing one or more embodiments are merely illustrative and not restrictive in all respects.

Claims

1. A single battery cell, comprising: A wound electrode assembly, the wound electrode assembly including a positive electrode, a negative electrode, and a diaphragm between the positive electrode and the negative electrode; as well as Electrolyte immersed in the wound electrode assembly The negative electrode includes: Negative electrode current collector; A layer of negative electrode active material on at least one surface of the negative electrode current collector; and The negative electrode terminal piece on the uncoated portion of the negative electrode current collector, The wound electrode assembly includes: A pair of bent portions on two opposite sides of the wound electrode assembly; and The flat portion between the pair of curved portions, The ratio of the area of ​​the negative electrode active material layer in the pair of curved portions to the total area of ​​the negative electrode active material layer is in the range of 18% to 50%. The electrolyte comprises a non-aqueous organic solvent, a lithium salt, and additives. The non-aqueous organic solvents mentioned above include ethylene carbonate and ethyl propionate. The volume ratio of ethylene carbonate to the non-aqueous organic solvent is in the range of 20% to 50% by volume. The volume ratio of ethyl propionate to the non-aqueous organic solvent is in the range of 50% to 80% by volume. The additives mentioned above include compounds represented by chemical formula 1. The amount of the additive is in the range of 1 to 10 parts by weight, based on 100 parts by weight of the electrolyte. Chemical Formula 1 and In chemical formula 1, X is a halogroup or a C1-C10 haloalkyl group. m1 is 1 or 2. When m1 is 1, m2 is 2, and When m1 is 2, m2 is 0.

2. The battery cell of claim 1, wherein the negative electrode active material layer is located on two opposite surfaces of the negative electrode current collector.

3. The battery cell of claim 1, wherein the negative electrode comprises two negative electrode terminals.

4. The battery cell of claim 1, wherein the positive electrode comprises: Positive electrode current collector; A layer of positive electrode active material on at least one surface of the positive electrode current collector; and Positive electrode terminals on the uncoated portion of the positive electrode current collector.

5. The battery cell of claim 4, wherein the positive electrode active material layer is located on two opposite surfaces of the positive electrode current collector.

6. The battery cell of claim 4, wherein the positive electrode comprises two positive electrode terminals.

7. The battery cell of claim 1, wherein the ratio of the width of the pair of curved portions to the width of the wound electrode assembly is in the range of 5% to 50%.

8. The battery cell of claim 1, wherein each of the pair of curved portions independently has a length of 1m. -1 ~1,000m -1 The curvature.

9. The battery cell of claim 1, wherein the mixture density of the negative electrode active material layer is in the range of 1.65 g / cc to 4.00 g / cc.

10. The battery cell of claim 1, wherein the battery cell operates at a voltage equal to or greater than 4.47V.

11. The battery cell of claim 1, wherein the ionic conductivity of the electrolyte is in the range of 7.2 mS / cm to 7.7 mS / cm.

12. The battery cell of claim 1, wherein the non-aqueous organic solvent further comprises propyl propionate.

13. The battery cell according to claim 1, wherein the non-aqueous organic solvent further comprises propylene carbonate.

14. The battery cell according to claim 1, wherein the lithium salt comprises LiPF6.

15. The battery cell according to claim 1, wherein the concentration of the lithium salt is in the range of 1.5 M to 2.0 M.

16. The battery cell according to claim 1, wherein the additive comprises lithium difluoro(oxalato)borate.

17. The battery cell according to claim 1, wherein based on 100 parts by weight of the electrolyte, the amount of the additive is in the range of 1 part by weight to 5 parts by weight.

18. The battery cell according to claim 1, wherein the positive electrode comprises a positive electrode active material layer, wherein the positive electrode active material layer comprises a lithium composite oxide represented by Chemical Formula 2, Chemical Formula 2 Li x M 1 y M 2 z M 3 1-y-z O 2-a X a and in, In Chemical Formula 2, 0.5 ≤ x ≤ 1.8, 0 ≤ a ≤ 0.05, 0 < y ≤ 1, 0 ≤ z ≤ 1, and 0 < y + z ≤ 1, M 1 M 2 and M 3 Each independently includes at least one element selected from Ni, Co, Mn, Al, B, Ba, Ca, Ce, Cr, Fe, Mo, Nb, Si, Sr, Mg, Ti, V, W, Zr, Y, and La, and X comprises at least one element selected from F, S, P, and Cl.

19. The battery cell according to claim 1, wherein the negative electrode active material layer comprises a carbon-based negative electrode active material, a Si-based negative electrode active material, a Sn-based negative electrode active material, or a combination thereof.

20. A rechargeable lithium battery, comprising: the battery cell according to any one of claims 1 to 19; and a pouch-type housing that houses the battery cell.

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