Sealing tape for rechargeable lithium battery and rechargeable lithium battery including same

Abstract

A sealing tape for a rechargeable lithium battery and a rechargeable lithium battery including the same are provided. The sealing tape includes a base layer and an adhesive layer on the base layer, in which the base layer includes an ethylene-vinyl acetate resin, the ethylene-vinyl acetate resin includes ethylene-derived repeating units and vinyl acetate-derived repeating units, and based on 100 wt% of the ethylene-vinyl acetate resin, the amount of the ethylene-vinyl acetate resin is less than 100 wt%. The content (e.g., amount) of repeat units derived from vinyl acetate is from about 5 wt% to about 15 wt%.

Description

Technical Field

[0001] The present disclosure relates to a sealing tape for a rechargeable lithium battery and a rechargeable lithium battery including the sealing tape. Background Art

[0002] Cylindrical rechargeable lithium batteries can generally be manufactured by the following processes (e.g., actions or tasks): a process of manufacturing a wound (or quasi) electrode assembly by winding a stack of a positive electrode, a separator and a negative electrode; a process of storing (e.g., containing) the wound (or quasi) electrode assembly in a cylindrical battery case; and a process of impregnating the wound (or quasi) electrode assembly with an electrolyte solution and then sealing it (e.g., a battery case).

[0003] The wound (or similar) electrode assembly is made smaller than the cylindrical battery case so that it can be accommodated in the cylindrical battery case. As a result, there is a certain gap (e.g., a gap of a certain size) between the cylindrical battery case and the wound (or similar) electrode assembly.

[0004] However, due to the presence of gaps, the wound (or similar) electrode assembly may rotate or flow (e.g., easily rotate or flow) inside the cylindrical battery case, resulting in deterioration in the performance of the rechargeable lithium battery (e.g., increased internal resistance, damage to electrode tabs, etc.).

[0005] In this regard, a method of attaching a sealing tape having an adhesive layer formed on a PET or PP substrate (hereinafter, referred to as a "prior art sealing tape") to the outer peripheral surface of the outermost layer of a wound (or similar) electrode assembly has been proposed. However, in comparable sealing tapes, the PET or PP substrate shows a small thickness change even if (for example, when) it is impregnated with an electrolyte solution, while the adhesive layer changes its thickness if (for example, when) it is impregnated with an electrolyte solution.

[0006] Therefore, comparable sealing tapes are easily detached from a wound type (or similar) electrode assembly impregnated with an electrolyte, and have limitations in inhibiting or reducing rotation and / or movement of the wound type (or similar) electrode assembly inside a cylindrical battery case.

[0007] Additionally, comparable sealing tapes fail to suppress or reduce abnormal phenomena such as heating and / or ignition of rechargeable lithium batteries. Summary of the invention

[0008] Aspects according to some embodiments relate to a novel sealing tape that effectively suppresses rotation and / or movement of a wound electrode assembly (eg, a wound-type (or quasi) electrode assembly) inside a cylindrical battery case while exhibiting flame retardancy.

[0009] Aspects according to some embodiments relate to a rechargeable lithium battery including the novel sealing tape.

[0010] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosed presented embodiments.

[0011] According to some embodiments, a sealing tape for a rechargeable lithium battery includes a base layer and an adhesive layer on the base layer, wherein the base layer includes an ethylene-vinyl acetate resin, the ethylene-vinyl acetate resin includes ethylene-derived repeating units and vinyl acetate-derived repeating units, and based on 100 wt % of the ethylene-vinyl acetate resin, the amount of the vinyl acetate-derived repeating units is about 5 wt % to about 15 wt %.

[0012] According to some embodiments, a rechargeable lithium battery includes: a cylindrical battery case; a wound electrode assembly housed in the cylindrical battery case; a sealing tape according to one or more embodiments, between an outermost layer of the wound electrode assembly and an inner (e.g., lower) layer thereof; and an electrolyte solution, impregnating the wound electrode assembly and the sealing tape.

[0013] The sealing tape of one or more embodiments may effectively inhibit or reduce the rotation and / or movement of a wound-type (or similar) electrode assembly inside a cylindrical battery case while exhibiting sufficient flame retardancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0015] Figure 1 is a schematic diagram of one or more embodiments of the novel sealing tape 200 prior to impregnation with an electrolyte solution.

[0016] Figure 2 is a schematic diagram of one or more embodiments of the novel sealing tape 200 after being impregnated with an electrolyte solution.

[0017] Figure 3 is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments. DETAILED DESCRIPTION

[0018] Hereinafter, specific embodiments will be described in more detail so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein.

[0019] The terms used herein are for describing the embodiments only and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, a singular expression includes a plural expression.

[0020] As used herein, the term "combination thereof" may refer to a mixture, stack, composite, copolymer, alloy, blend, or reaction product of the components.

[0021] Here, it will be understood that terms such as "includes," "comprising," or "having" are intended to indicate the presence of the embodied features, quantities, (e.g., actions or tasks) steps, elements, or (e.g., any suitable) combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, quantities, (e.g., actions or tasks) steps, elements, or (e.g., any suitable) combinations thereof.

[0022] In the drawings, for the sake of clarity, the thickness of layers, films, panels, regions, etc. is exaggerated, and the same reference numerals always represent the same elements, and their repeated description may not be provided in the specification. It will be understood that if (for example, when) an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element, or there may be intervening elements. Conversely, if (for example, when) an element is referred to as being "directly on" another element, there are no intervening elements.

[0023] The term "layer" used herein includes not only a shape formed on the entire surface if (for example, when) viewed from a plan view but also a shape formed on a partial surface.

[0024] The term "thickness" as used herein can be measured, for example, by a photograph taken with an optical microscope or an electron microscope (such as a scanning electron microscope).

[0025] In addition, the average particle size can be measured by a suitable method (e.g., known to those skilled in the art), for example, it can be measured by a particle size analyzer, or it can be measured by a transmission electron microscope image or a scanning electron microscope image. In one or more embodiments, the average particle size value can be obtained by measuring using a dynamic light scattering method, performing data analysis, counting the number of particles in each particle size range, and calculating therefrom. Unless otherwise defined, the average particle size can refer to the diameter (D) of particles with a cumulative volume of 50% by volume in a particle size distribution. 50 As used herein, if (e.g., when) no definition is otherwise provided, the average particle diameter refers to the diameter (D) of particles accounting for 50% by volume of the cumulative volume in a particle size distribution obtained by randomly measuring the size (diameter or length of the major axis) of about 20 particles in a scanning electron microscope image. 50). In addition, unless otherwise defined, in the present disclosure, if (for example, when) the particles are spherical, the term "particle size" refers to the average diameter, and if (for example, when) the particles are non-spherical, the term "particle size" refers to the average major axis length.

[0026] (Sealing tape)

[0027] According to some embodiments, a sealing tape for a rechargeable lithium battery includes a base layer and an adhesive layer on the base layer, wherein the base layer includes an ethylene-vinyl acetate resin comprising ethylene-derived repeating units and vinyl acetate-derived repeating units, and based on 100 wt % of the ethylene-vinyl acetate resin, the content (e.g., amount) of the repeating units derived from vinyl acetate is about 5 wt % to about 15 wt %.

[0028] Content of vinyl acetate-derived repeating units in ethylene-vinyl acetate resin

[0029] Ethylene-vinyl acetate resins including ethylene-derived repeating units and vinyl acetate-derived repeating units undergo reactions such as free radical recombination, instantaneous crosslinking, Diels-Alder cycloaddition, etc. during thermal decomposition. As a result, ethylene-vinyl acetate resins delay combustion, and even if combustion occurs, clear char is formed while emitting less harmful gases. Therefore, ethylene-vinyl acetate resins can be used as substitutes for halogen-based flame retardants.

[0030] However, if the content (e.g., amount) of the vinyl acetate-derived repeating unit is greater than about 15 wt % based on about 100 wt % of the ethylene-vinyl acetate resin, the melting point of the ethylene-vinyl acetate resin is reduced to less than or equal to about 85° C., resulting in a problem that the ethylene-vinyl acetate resin melts under the flame retardancy evaluation conditions of a rechargeable lithium battery. In addition, if the content (e.g., amount) of the vinyl acetate-derived repeating unit is greater than about 15 wt % based on about 100 wt % of the ethylene-vinyl acetate resin, the base layer may swell excessively (or substantially) according to (e.g., in response to) impregnation with an electrolyte solution, and thus may be separated from the adhesive layer.

[0031] In contrast, if the content (eg, amount) of the vinyl acetate-derived repeating unit is less than about 5 wt % based on about 100 wt % of the ethylene-vinyl acetate resin, the flame retardant effect may be minimal or insufficient.

[0032] In contrast, if the content (e.g., amount) of the vinyl acetate-derived repeating unit is about 5 wt% to about 15 wt% based on about 100 wt% of the ethylene-vinyl acetate resin, the ethylene-vinyl acetate resin can remain stable under the flame retardancy evaluation conditions of a rechargeable lithium battery because the melting point of the ethylene-vinyl acetate resin can be increased to greater than or equal to about 90°C.

[0033] For example, based on 100 wt % of the ethylene-vinyl acetate resin, the content (e.g., amount) of the vinyl acetate-derived repeating units can be greater than or equal to about 5 wt %, greater than or equal to about 6 wt %, or greater than or equal to about 6.5 wt %, and less than or equal to about 15 wt %, less than or equal to 14 wt %, less than or equal to about 13 wt %, or less than or equal to about 12 wt %.

[0034] Swelling rate

[0035] The base layer and the adhesive layer may exhibit different longitudinal swelling rates upon (eg, in response to) impregnation with the electrolyte solution.

[0036] In the present specification, "impregnated with an electrolyte solution" of a specific object means that the electrolyte solution permeates into the specific object.

[0037] The longitudinal swelling ratio (A) of the adhesive layer is measured by the following method.

[0038] The adhesive layer was cut into a size of width×length=10 mm×10 mm to prepare a sample for measuring the longitudinal swelling rate (the longitudinal length of the adhesive layer before being impregnated with the electrolyte solution, A1=10 mm). The sample for measuring the longitudinal swelling rate was impregnated with the electrolyte solution, allowed to stand at room temperature for about one day, and then the longitudinal length was measured (the longitudinal length of the adhesive layer after being impregnated with the electrolyte solution, A2).

[0039] The longitudinal length (A1) of the adhesive layer before impregnation with the electrolyte solution and the longitudinal length (A2) of the adhesive layer after impregnation with the electrolyte solution are substituted (eg, incorporated or inserted) into Equation 1 to obtain a longitudinal swelling ratio (A) of the adhesive layer.

[0040] [Equation 1]

[0041] Longitudinal swelling ratio of adhesive layer (A) (%) = (A2-A1) / A1×100

[0042] In equation 1,

[0043] A1 is the longitudinal length of the adhesive layer before electrolyte impregnation (eg, before impregnation with an electrolyte solution), and

[0044] A2 is the longitudinal length of the adhesive layer after being impregnated with the electrolyte solution.

[0045] The longitudinal swelling ratio (B) of the substrate layer is measured in the following manner.

[0046] The substrate layer was cut into a size of width×length=10 mm×10 mm to prepare a sample for measuring the longitudinal swelling rate (the longitudinal length of the substrate layer before being impregnated with the electrolyte solution, B1=10 mm). The sample for measuring the longitudinal swelling rate was impregnated with the electrolyte solution, sealed, and allowed to stand at room temperature for about 1 day to measure the length (the longitudinal length of the substrate after being impregnated with the electrolyte solution, B2).

[0047] The longitudinal length (B1) of the substrate layer before impregnation with the electrolyte solution and the longitudinal length (B2) of the substrate layer after impregnation with the electrolyte solution are substituted (eg, incorporated or inserted) into Equation 2 to calculate the longitudinal swelling ratio (B) of the substrate layer.

[0048] [Equation 2]

[0049] The longitudinal swelling ratio of the base layer (B) (%) = (B2-B1) / B1×100

[0050] In equation 2,

[0051] B1 is the longitudinal length of the substrate layer before being impregnated with the electrolyte solution, and

[0052] B2 is the longitudinal length of the base layer after being impregnated with the electrolyte solution.

[0053] The electrolyte solution is not particularly limited, but may include a non-aqueous organic solvent and a lithium salt. In some embodiments, the non-aqueous organic solvent may be ethylene carbonate (EC) and dimethyl carbonate (DMC). In some embodiments, the non-aqueous organic solvent may also include propylene carbonate (PC) and fluorobenzene (FB); and the lithium salt may include LiPF6.

[0054] Based on 100% by volume of the non-aqueous organic solvent, the content of ethylene carbonate (EC) may be about 10% by volume to about 50% by volume, or about 20% by volume to about 40% by volume; the content of dimethyl carbonate (DMC) may be about 40% by volume to about 70% by volume, or about 50% by volume to about 60% by volume; the content of propylene carbonate (PC) may be about 0.1% by volume to about 15% by volume, or about 1% by volume to about 10% by volume, and the content of fluorobenzene (FB) may be about 1% by volume to about 20% by volume, or about 5% by volume to about 15% by volume.

[0055] In the electrolyte solution, the molar concentration of the lithium salt may be about 0.8 to about 1.5M, about 0.9 to about 1.3M, or about 1.0 to about 1.2M.

[0056] Figure 1 2 is a schematic diagram of a novel sealing tape 200 of one or more embodiments before being impregnated with an electrolyte solution. Before the novel sealing tape of one or more embodiments is impregnated with an electrolyte solution, two objects that are separated and / or separated (e.g., spaced or separated) from each other can be effectively fixed by a mutual balance between the adhesive force of the adhesive layer 220 and the adhesive force of the base layer 210.

[0057] Figure 2 2 is a schematic diagram of a novel sealing tape 200 of one or more embodiments after being impregnated with an electrolyte solution. After the novel sealing tape of one or more embodiments is impregnated with an electrolyte solution, a three-dimensional shape that can fill a gap between two objects that are spaced apart and / or separated (e.g., separated) from each other is achieved by balancing the longitudinal swelling rate that occurs after the adhesive layer 220 and the base layer 210 are impregnated with the electrolyte solution.

[0058] Therefore, the novel sealing tape of one or more embodiments effectively fills the gap between the cylindrical battery case and the wound (or similar) electrode assembly through the three-dimensional shape achieved by electrolyte impregnation, thereby preventing or reducing the rotation and / or movement of the wound (or similar) electrode assembly inside the cylindrical battery case and the performance degradation of the rechargeable lithium battery.

[0059] Although a more detailed description will be provided later, the novel sealing tape of one or more embodiments may be attached to the outer peripheral surface of the outermost layer of a wound (or similar) electrode assembly. In some embodiments, the novel sealing tape of one or more embodiments may be placed between the outermost layer of a wound (or similar) electrode assembly and its inner (e.g., lower) layer (e.g., between the inner surface of the outermost layer of a wound (or similar) electrode assembly and the inner layer immediately below the outermost layer of a wound (or similar) electrode assembly).

[0060] In one or more embodiments, the adhesive layer may have a longitudinal swelling ratio (A) according to Equation 1 in the range of about 110% to about 150%, about 110% to about 140%, about 110% to about 130%, or about 119% to about 125%.

[0061] In one or more embodiments, the base layer may have a longitudinal swelling ratio (B) according to Equation 2 in the range of about 100% to about 130%, about 105% to about 120%, or about 110% to about 115%.

[0062] If the above range is satisfied, a three-dimensional shape that can fill a gap between two objects spaced apart and / or separated (eg, separated) from each other may be achieved by balancing the longitudinal expansion rate occurring after each of the adhesive layer 220 and the base layer 210 is impregnated with an electrolyte solution.

[0063] However, if the longitudinal swelling rate (A) of the adhesive layer 220 is lower than the above range, it may not be sufficient to fix two objects that are spaced and / or separated (e.g., separated) from each other. If the longitudinal swelling rate (A) of the adhesive layer 220 exceeds the above range, the volume of the cylindrical battery case may be excessively (or substantially) expanded.

[0064] In contrast, if the longitudinal swelling rate (B) of the base layer 210 does not satisfy these ranges, the longitudinal swelling rate (B) is not balanced with the longitudinal swelling rate (A) of the adhesive layer 220 .

[0065] If the longitudinal swelling ratio (A) of the adhesive layer and the longitudinal swelling ratio (B) of the base layer satisfy the respective ranges, the longitudinal swelling ratio (A) of the adhesive layer may be greater than the longitudinal swelling ratio (B) of the base layer.

[0066] For example, the ratio (A / B) of the longitudinal swelling rate (A) of the adhesive layer to the longitudinal swelling rate (B) of the base layer may be greater than about 1, greater than or equal to about 1.01, greater than or equal to about 1.02, or greater than or equal to about 1.03; and less than or equal to about 1.15, less than or equal to about 1.13, less than or equal to about 1.1, or less than or equal to about 1.09.

[0067] If the ratio (A / B) of the longitudinal swelling rate (A) of the adhesive layer to the longitudinal swelling rate (B) of the base layer satisfies these ranges, the longitudinal swelling rate (A) of the adhesive layer 220 may be balanced with the longitudinal swelling rate (B) of the base layer 210 .

[0068] Gel fraction of adhesive layer

[0069] The adhesive layer may have a gel fraction of greater than or equal to about 70wt%, greater than or equal to about 75wt%, or greater than or equal to about 80wt%. If the gel fraction of the adhesive layer is less than about 70wt%, the adhesive layer may (e.g., excessively) swell and disperse. The upper limit of the gel fraction of the adhesive layer is not particularly limited, but may be less than about 100wt%.

[0070] The gel fraction of the adhesive layer can be obtained by the following method.

[0071] Take 1g (W0) of the sample for gel fraction measurement and put it into a 20mL vial, add 1,2,4-trichlorobenzene (about 10mL) to fully immerse the sample for gel fraction measurement, and heat the sample at 130°C for greater than or equal to about 2 hours. The heated solution is filtered and separated using a 200-mesh wire mesh. Here, the unfiltered and undissolved components are washed twice in a xylene solution and then dried in a hot air oven at 120°C for 12 hours. Finally, the dried undissolved component (W) is measured and the gel fraction is calculated using Equation 3.

[0072] [Equation 3]

[0073] Gel fraction (%) = (W / W0) × 100.

[0074] In Equation 3, W is the weight of the dried undissolved component; and W0 is the weight of the initial bonding layer sample, ie, 1 g.

[0075] Peel strength of adhesive layer

[0076] The adhesive layer may achieve a suitable (eg, specific) peel strength due to its adhesiveness.

[0077] For example, the adhesive layer may have a T-peel peel strength of about 60 gf / cm or more, about 100 gf / cm or more, about 200 gf / cm or more, about 250 gf / cm or more, or about 280 gf / cm or more, measured at a peeling speed of 60 mm / min and a peeling angle of 180 degrees relative to the substrate to which the adhesive layer is attached. The upper limit of the peel strength of the adhesive layer is not particularly limited, but may be less than or equal to about 360 gf / cm.

[0078] The peel strength of the adhesive layer can be measured by the following method.

[0079] As the substrate to be attached, two copper substrates with a width × length × thickness = 150mm × 10mm × 10μm are prepared. An adhesive layer of 100mm × 30mm × 10μm (width × height × thickness) is placed between the two copper substrates to obtain a sample for measuring peel strength. The sample for measuring peel strength is pressurized for 1000 seconds at a pressure of 3.5 bar and a temperature of 50°C using an autoclave. At 25°C, one copper substrate of the pressurized sample for measuring peel strength is fixed to a universal physical property analyzer (product name: TA.XT_Plus Texture Analyzer, manufacturer: Stable Micro System), the other copper substrate is moved at a speed of 60mm / min, and the T-type peeling strength is measured by pulling it.

[0080] Composition of adhesive layer

[0081] The adhesive layer may include an acrylic adhesive.

[0082] The acrylic adhesive may be a copolymer of 2-ethylhexyl acrylate and 4-hydroxybutyl acrylate cross-linked with an isocyanate cross-linking agent.

[0083] (Rechargeable lithium battery)

[0084] According to some embodiments, a rechargeable lithium battery includes: a cylindrical battery case; a wound (or similar) electrode assembly, housed in the cylindrical battery case; a novel sealing tape of one or more embodiments, arranged between the outermost layer of the wound (or similar) electrode assembly and its inner (e.g., lower) layer (e.g., between the inner surface of the outermost layer of the wound (or similar) electrode assembly and the inner layer immediately below the outermost layer of the wound (or similar) electrode assembly); and an electrolyte solution impregnated in the wound (or similar) electrode assembly and the sealing tape.

[0085] The sealing tape of one or more embodiments has a three-dimensional shape achieved by impregnation with an electrolyte solution, so that when placed between the outermost layer of a wound (or similar) electrode assembly and its inner (e.g., lower) layer (e.g., between the outermost layer of a wound (or similar) electrode assembly and the inner layer immediately below the outermost layer of the wound (or similar) electrode assembly), the gap between the cylindrical battery case and the wound (or similar) electrode assembly is effectively filled. As a result, the sealing tape of one or more embodiments arranged between the outermost layer of a wound (or similar) electrode assembly and its inner (e.g., lower) layer (e.g., between the inner surface of the outermost layer of a wound (or similar) electrode assembly and the inner layer immediately below the outermost layer of the wound (or similar) electrode assembly) inhibits the rotation and / or movement of the wound (or similar) electrode assembly inside the cylindrical battery case, and can prevent or reduce the performance degradation of the rechargeable lithium battery.

[0086] As described above, in some embodiments, the novel sealing tape of one or more embodiments may be attached to the outer peripheral surface of the outermost layer of a wound (or similar) electrode assembly. In some embodiments, the novel sealing tape of one or more embodiments is ideally placed between the outermost layer of a wound (or similar) electrode assembly and its inner (e.g., lower) layer (e.g., between the inner surface of the outermost layer of a wound (or similar) electrode assembly and the inner layer immediately below the outermost layer of a wound (or similar) electrode assembly). In the latter case, the capacity of a rechargeable lithium battery can be further improved by increasing the density of the positive electrode and / or the negative electrode compared to the former case.

[0087] Figure 3 is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments.

[0088] Hereinafter, a rechargeable lithium battery according to one or more embodiments will be described in more detail except for descriptions repeated above.

[0089] Wound (or similar) electrode assembly

[0090] The wound type (or quasi) electrode assembly may be a stacked body in which a positive electrode, a separator, and a negative electrode are sequentially stacked and wound in such a manner that the negative electrode may be the outermost layer.

[0091] Therefore, the fixing force between the outermost layer (negative electrode) of the wound type (or similar) electrode assembly and the inner (eg, lower) layer (separator) thereof can be enhanced.

[0092] The length of the sealing tape may be about 0.8 times to about 1.5 times the circumference of the wound type (or similar) electrode assembly.

[0093] A portion of the sealing tape may be exposed to the outside of the outermost layer of the wound (or similar) electrode assembly (e.g., a portion of the sealing tape may be between the outermost layer of the wound (or similar) electrode assembly and the battery case). For example, if the length of the sealing tape exceeds about 1 times the circumference of the wound (or similar) electrode assembly, the sealing tape is exposed to the outside of the wound (or similar) electrode assembly with an excess portion of the length, and the wound (or similar) electrode assembly can be effectively prevented or reduced from rotating or moving inside the cylindrical battery case.

[0094] Positive electrode active material

[0095] The positive electrode active material may include a lithiated intercalation compound that can reversibly intercalate and deintercalate lithium ions. For example, the positive electrode active material may include one or more composite oxides of a metal selected from cobalt, manganese, nickel, and (eg, any suitable) combinations thereof and lithium.

[0096] The composite oxide may be a lithium transition metal composite oxide, and non-limiting specific examples may include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free lithium nickel manganese-based oxides, or (e.g., any suitable) combinations thereof.

[0097] As an example, based on 100 mol% of metals other than lithium in the lithium transition metal composite oxide, the positive electrode active material can be a high nickel-based positive electrode active material having a nickel content (e.g., amount) greater than or equal to about 80 mol%. Based on 100 mol% of metals other than lithium in the lithium transition metal composite oxide, the content (e.g., amount) of nickel in the high nickel-based positive electrode active material can be greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol%. High nickel-based positive electrode active materials can achieve high capacity and can be applied to high capacity, high density rechargeable lithium batteries.

[0098] As a more specific non-limiting example, a compound represented by any one of the following chemical formulae (eg, any one selected from the following chemical formulae) may be used: Li a A 1-b X b O 2-c D c(0.90≤a≤、1.8,0≤b≤0.5,0≤c≤0.05);Li a Mn 2-b X b The 4-c D c (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05);Li a Ni 1-b-c Co b X c The 2-α D α (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni 1-b-c Mn b X c The 2-α D α (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8,0≤b≤0.9,0≤c≤0.5,0≤d≤0.5,0≤e≤0.1);Li a NiG b O2(0.90≤a≤1.8,0.001≤b≤0.1);Li a CoG b O2(0.90≤a≤1.8,0.001≤b≤0.1);Li a Mn 1-b G b O2(0.90≤a≤1.8,0.001≤b≤0.1);Li a Mn2G b O4(0.90≤a≤1.8,0.001≤b≤0.1);Li a Mn 1-g G g PO4(0.90≤a≤1.8,0≤g≤0.5);Li (3-f) Fe2(PO4)3(0≤f≤2); and Li a FePO4(0.90≤a≤1.8).

[0099] In the above chemical formula, A is Ni, Co, Mn, or (e.g., any suitable) combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or (e.g., any suitable) combination thereof; D is O, F, S, P, or (e.g., any suitable) combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or (e.g., any suitable) combination thereof; Q is Ti, Mo, Mn, or (e.g., any suitable) combination thereof; Z is Cr, V, Fe, Sc, Y, or (e.g., any suitable) combination thereof; and L 1 is Mn, Al, or a (eg, any suitable) combination thereof.

[0100] Positive electrode

[0101] A positive electrode for a rechargeable lithium battery may include a current collector and a positive electrode active material layer on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0102] The amount of the positive electrode active material may be about 90 wt % to about 99.5 wt % based on 100 wt % of the positive electrode active material layer.

[0103] In one or more embodiments, the positive electrode active material layer may further include a binder and a conductive material. Here, the amount of the binder and the conductive material may be about 0.5 wt % to about 5 wt %, respectively, based on 100 wt % of the positive electrode active material layer.

[0104] The binder is used to attach the positive electrode active material particles to each other (e.g., well), and also to attach the positive electrode active material to the current collector (e.g., well). Examples of binders may include (e.g., may be) polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth) acrylated styrene-butadiene rubber, epoxy resin, (meth) acrylic resin, polyester resin, nylon, or (e.g., any suitable) combination thereof, but the present disclosure is not limited thereto.

[0105] A conductive material can be used to impart conductivity (e.g., electrical conductivity) to an electrode, and any material that does not cause a chemical change (e.g., does not cause an undesired chemical change in a rechargeable lithium battery) and conducts electrons can be used in a battery. Examples of conductive materials can include: carbonaceous materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and / or carbon nanotube; metallic materials in the form of metal powder or metal fiber, including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and / or mixtures thereof.

[0106] In some embodiments, Al can be used as a current collector, but the present disclosure is not limited thereto.

[0107] Negative electrode active material

[0108] The negative electrode active material can be a material that reversibly intercalates / deintercalates lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping lithium, or a transition metal oxide. The material capable of reversibly intercalating / deintercalating lithium ions can be a carbonaceous negative electrode active material that can include, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon can be graphite, such as natural graphite or artificial graphite in an irregular shape, flake shape, platelet shape, spherical shape, or fibrous shape. The amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbonization product, calcined coke, etc.

[0109] The lithium metal alloy can include lithium and a metal selected from among Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0110] The material capable of doping / dedoping lithium can be a Si-based negative electrode active material or a Sn-based negative electrode active material. The Si-based negative electrode active material can include silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2), a Si-Q alloy (where Q is selected from an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element (excluding Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, or a combination thereof (e.g., any suitable combination), and can be selected from, for example, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof (e.g., any suitable combination)). The Sn-based negative electrode active material can include Sn, SnO x (0 < x ≤ 2, for example, SnO2), a Sn alloy, or a combination thereof (e.g., any suitable combination).

[0111] The silicon-carbon composite can be a composite of silicon and amorphous carbon. The average particle size (D 50 ) of the silicon-carbon composite particles (e.g., secondary particles) can be, for example, from about 0.5 μm to about 20 μm. According to one or more embodiments, the silicon-carbon composite can be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite can include secondary particles (cores) in which silicon primary particles are aggregated and an amorphous carbon coating layer (shell) on the surface of the secondary particles. Amorphous carbon can also be present between the silicon primary particles. For example, the silicon primary particles can be coated with amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0112] The silicon-carbon composite can also include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core. The crystalline carbon can be artificial graphite, natural graphite, or a combination thereof (e.g., any suitable combination). The amorphous carbon can include soft carbon or hard carbon, mesophase pitch carbonized products, and calcined coke.

[0113] If (e.g., when) the silicon-carbon composite includes silicon and amorphous carbon, then based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be from about 10 wt% to about 50 wt%, and the content (e.g., amount) of amorphous carbon can be from about 50 wt% to about 90 wt%. In one or more embodiments, if (e.g., when) the composite includes silicon, amorphous carbon, and crystalline carbon, then based on 100 wt% of the silicon-carbon composite, the content (e.g., amount) of silicon can be from about 10 wt% to about 50 wt%, the content (e.g., amount) of crystalline carbon can be from about 10 wt% to about 70 wt%, and the content (e.g., amount) of amorphous carbon can be from about 20 wt% to about 40 wt%.

[0114] In some embodiments, the thickness of the amorphous carbon coating can be from about 5 nm to about 100 nm. The average particle size (D 50 ) of the silicon particles (primary particles) can be from about 10 nm to about 1 μm, or from about 10 nm to about 200 nm. The silicon particles can exist alone as silicon, in the form of a silicon alloy, or in an oxidized form (can be presented alone as silicon, in the form of a silicon alloy, or in an oxidized form). The oxidized form of silicon can be represented by SiO x (0 < x ≤ 2). Here, the atomic content (e.g., amount) ratio of Si:O indicating the degree of oxidation can be from about 99:1 to about 33:67. As used herein, if (e.g., when) no other definition is provided, then the average particle size (D 50 ) represents the particles with a cumulative volume of about 50% by volume in the particle size distribution.

[0115] The Si-based negative electrode active material or the Sn-based negative electrode active material may be used in combination with the carbon-based negative electrode active material. When a mixture of the Si-based negative electrode active material or the Sn-based negative electrode active material and the carbon-based negative electrode active material is used, the mixing ratio may be about 1:99 to about 90:10 by weight.

[0116] Negative electrode

[0117] The negative electrode for a rechargeable lithium battery includes a current collector and a negative electrode active material layer on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0118] Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material may be about 95wt% to about 99.5wt%. Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the binder may be about 0.5wt% to about 5wt%. Based on 100wt% of the negative electrode active material layer, the content (e.g., amount) of the conductive material may be about 0.5wt% to about 5wt%. For example, the negative electrode active material layer may include about 90wt% to about 99wt% of the negative electrode active material, about 0.5wt% to about 5wt% of the binder, and about 0.5wt% to about 5wt% of the conductive material.

[0119] The binder can be used to attach the negative electrode active material particles to each other (e.g., well), and also to attach the negative electrode active material to the current collector (e.g., well). The binder can include a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof (e.g., any suitable).

[0120] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or (eg, any suitable) combination thereof.

[0121] The aqueous binder can be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol or (e.g., any suitable) combination thereof.

[0122] When an aqueous binder is used as a negative electrode binder, the negative electrode binder may further include a cellulose compound capable of imparting viscosity. The cellulose compound includes one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and alkali metal salts thereof. The alkali metal may be Na, K or Li.

[0123] The dry binder may be a polymer material capable of fiberization (eg, taking the form of fibers), and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or (eg, any suitable) combinations thereof.

[0124] The conductive material is included to provide electrode conductivity, and any conductive material can be used as the conductive material unless it causes a chemical change. Examples of the conductive material may be: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials in the form of metal powder or metal fiber, such as copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and / or (e.g., any suitable) mixtures thereof.

[0125] The negative electrode current collector may include one selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and (eg, any suitable) combinations thereof, but the present disclosure is not limited thereto.

[0126] Electrolyte solution

[0127] The electrolyte solution for a rechargeable lithium battery includes a non-aqueous organic solvent and a lithium salt.

[0128] The nonaqueous organic solvent serves as a medium for transferring (eg, transporting) ions participating in an electrochemical reaction of a battery.

[0129] The non-aqueous organic solvent may be a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent, an aprotic solvent, or (eg, any suitable) combination thereof.

[0130] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, valerolactone, caprolactone, etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. Ketone solvents may include cyclohexanone. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include nitriles such as R-CN (wherein R is a C2-C20 straight chain, branched or cyclic hydrocarbon group, a double bond, an aromatic ring or an ether group), amides (such as dimethylformamide), dioxolanes (such as 1,3-dioxolane and / or 1,4-dioxolane), cyclopentane, etc.

[0131] The non-aqueous organic solvent may be used alone or as a mixture of two or more types (species), and if (for example, when) two or more types (species) are used as a mixture, the mixing ratio may be appropriately or suitably adjusted according to the desired or suitable battery performance which may be widely understood by those skilled in the art.

[0132] In addition, if (for example, when) a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate may be mixed and used, and the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0133] The non-aqueous organic solvent may also include an aromatic hydrocarbon organic solvent. For example, a carbonate solvent and an aromatic hydrocarbon organic solvent may be mixed and used in a volume ratio of about 1:1 to about 30:1.

[0134] In order to improve the cycle life of the battery, the electrolyte may further include ethyl vinyl carbonate, vinylene carbonate or ethylene carbonate-based compounds.

[0135] Examples of the ethylene carbonate-based compound may include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, and cyanoethylene carbonate.

[0136] The lithium salt dissolved in the organic solvent supplies lithium ions in the battery, allows the basic operation of the rechargeable lithium battery, and improves the transport of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts 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 F2 x+1 SO2)(C y F 2y+1 SO2) (wherein x and y are integers of 1 to 20), one or more of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB) and lithium bis(oxalato)borate (LiBOB).

[0137] The concentration of the lithium salt may be used in the range of about 0.1 M to about 2.0 M. If the concentration of the lithium salt is within the above range, the electrolyte solution has appropriate or suitable ion conductivity and viscosity, so that excellent or suitable performance may be achieved, and lithium ions may be efficiently moved.

[0138] Diaphragm

[0139] Depending on the type or kind of rechargeable lithium battery, the separator may be present between the positive electrode and the negative electrode. The separator may include polyethylene, polypropylene, polyvinylidene fluoride, a multilayer film of two or more layers thereof, a mixed multilayer film (such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator and / or a polypropylene / polyethylene / polypropylene three-layer separator), etc.

[0140] The separator may include a porous substrate and a coating layer including an organic material, an inorganic material, or (eg, any suitable) combination thereof on the porous substrate (eg, one or both surfaces or sides (eg, opposite sides) of the porous substrate).

[0141] The porous substrate can be a polymer film formed by any one selected from the group consisting of polymer polyolefins (such as polyethylene and / or polypropylene), polyesters (such as polyethylene terephthalate, polybutylene terephthalate and / or polyethylene naphthalate), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, glass fibers, polytetrafluoroethylene (e.g., Teflon), and copolymers or mixtures of two or more thereof.

[0142] The porous substrate may have a thickness of about 1 micrometer (μm) to about 40 μm, for example, about 1 μm to about 30 μm, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 10 μm to about 15 μm.

[0143] The organic material may include a (meth)acryl copolymer, the (meth)acryl copolymer including a first structural unit and a second structural unit, the first structural unit is derived from (meth)acrylamide, and the second structural unit includes at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate and a structural unit derived from (meth)acrylamidesulfonic acid or its salt.

[0144] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, or a combination thereof (e.g., any suitable combination), but the present disclosure is not limited thereto. The average particle size (D 50 ) can be from about 1 nanometer (nm) to about 2000 nm, for example, from about 100 nm to about 1000 nm, or from about 100 nm to about 700 nm.

[0145] The organic material and the inorganic material may be mixed in one coating layer, or may exist in the form of a stack of a coating layer including an organic material and a coating layer including an inorganic material.

[0146] The coating layer may have a thickness of about 0.5 μm to about 20 μm, for example, about 1 μm to about 10 μm, or about 1 μm to about 5 μm.

[0147] Rechargeable lithium battery

[0148] Rechargeable lithium batteries may be classified into cylindrical, prismatic, pouch or coin-type (or similar) batteries, etc., according to their shapes. Figure 3 is a schematic diagram showing a rechargeable lithium battery according to one or more embodiments. Figure 3 , the rechargeable lithium battery 100 may include an electrode assembly in which a separator 30 is located between a positive electrode 10 and a negative electrode 20, and a case 50 accommodating the electrode assembly. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte solution. Figure 3 As shown in , the rechargeable lithium battery 100 may include a sealing member 60 that seals the case 50 .

[0149] Example 1

[0150] (1) Preparation of base layer

[0151] As the ethylene-vinyl acetate resin including ethylene-derived repeating units and vinyl acetate-derived repeating units, an ethylene-vinyl acetate resin (product name: EF320, manufacturer: LG Chem) including 6.5 wt % of vinyl acetate-derived repeating units based on 100 wt % of the ethylene-vinyl acetate resin was prepared.

[0152] Subsequently, 10 parts by weight of acrylyl diphosphoric acid (ADP) was added thereto based on 100 parts by weight of the ethylene-vinyl acetate resin, and then extruded in an extruder to obtain a 20 μm-thick base layer.

[0153] (2) Preparation of adhesive layer

[0154] 85 parts by weight of ethyl acetate and 15 parts by weight of toluene as a solvent, 95 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of 4-hydroxybutyl acrylate as monomers, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were mixed, gently stirred after replacing with a nitrogen atmosphere, and polymerized for 8 hours while maintaining the temperature at 55°C to obtain an acrylic prepolymer having a weight average molecular weight (Mw) of 1,300,000 g / mol and Mw / Mn=1.84.

[0155] To 100 parts by weight of the acrylic prepolymer was added 0.05 parts by weight of a trimethylolpropane adduct of xylene diisocyanate (product name: Takenate D110N, XDI, manufacturer: Mitsui Chemicals) to prepare an acrylic adhesive composition.

[0156] The acrylic adhesive composition was coated on the release film and dried at 135° C. for 3 minutes to obtain an adhesive layer having a thickness of 15 μm.

[0157] (3) Manufacturing of sealing tape

[0158] The adhesive layer was transferred onto the hard coating layer (ie, base layer) to prepare a sealing tape.

[0159] (4) Manufacturing of rechargeable lithium battery cells

[0160] LiNi as the positive electrode active material 0.75 Mn 0.23 Al 0.02 O2, polyvinylidene fluoride as a binder, and acetylene black as a conductive material were mixed in a weight ratio of 96:3:1 and dispersed in N-methylpyrrolidone to prepare a positive electrode active material slurry.

[0161] The positive electrode active material slurry was coated on a 15 μm thick Al foil, dried at 100° C., and then pressed to manufacture a positive electrode.

[0162] Artificial graphite was used as a negative electrode active material, and the negative electrode active material, styrene butadiene rubber binder, and carboxymethyl cellulose were mixed at a weight ratio of 98:1:1 and dispersed in distilled water to prepare a negative electrode active material slurry.

[0163] The negative electrode active material slurry was coated on a 10 μm-thick Cu foil, dried at 100° C., and then pressed to prepare a negative electrode.

[0164] A separator (thickness 10 μm) made of polyethylene is placed between the positive electrode and the negative electrode to prepare a stack, and the stack is wound in such a way that the negative electrode becomes the outermost layer to manufacture a wound (or similar) electrode assembly (circumference: 64 mm). The sealing tape is cut into a length of 70 mm and placed in the gap between the outermost layer (negative electrode) and the inner (e.g., lower) layer (separator) of the wound (or similar) electrode assembly. Here, a portion (60 mm) of the sealing tape is exposed to the outside of the wound (or similar) electrode assembly. That is, a portion (e.g., 10 mm) of the sealing tape is placed between the negative electrode (the outermost layer of the wound (or similar) electrode assembly) and the separator (the inner layer immediately below the outermost layer of the wound (or similar) electrode assembly), and the rest of the sealing tape (e.g., 60 mm) is exposed to the outside of the wound (or similar) electrode assembly, for example, by being wound around the outer surface of the negative electrode (the outermost layer of the wound (or similar) electrode assembly).

[0165] The wound type (or similar) electrode assembly having the sealing tape placed thereon is stored in a cylindrical battery case, an electrolyte solution is injected, and the battery case is sealed to obtain a rechargeable lithium battery cell.

[0166] The electrolyte solution is 1.1 M concentration of LiPF6 dissolved in a mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate (PC) and fluorobenzene (FB) (volume ratio of EC:DMC:PC:FB=30:55:5:10).

[0167] Example 2

[0168] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that ethylene-vinyl acetate resin having 9.5 wt % of vinyl acetate-derived repeating units based on 100 wt % of the ethylene-vinyl acetate resin (product name: EVA2240, manufacturer: Hanwha Solutions) was used.

[0169] Example 3

[0170] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that an ethylene-vinyl acetate resin having 12 wt % of vinyl acetate-derived repeating units based on 100 wt % of the ethylene-vinyl acetate resin (product name: EVA2250, manufacturer: Hanwha Solutions) was used.

[0171] Example 4

[0172] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the thickness of the adhesive layer was changed to 10 μm.

[0173] Example 5

[0174] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that the thickness of the adhesive layer was changed to 20 μm.

[0175] Comparative Example 1

[0176] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that a 20 μm-thick PET film was used as the base layer.

[0177] Comparative Example 2

[0178] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that ethylene-vinyl acetate resin having 3.5 wt % of ethylene-derived repeating units based on 100 wt % of the ethylene-vinyl acetate resin (product name: EF221, manufacturer: LG Chem) was used.

[0179] Comparison Example 3

[0180] A sealing tape and a rechargeable lithium battery cell were manufactured in substantially the same manner as in Example 1, except that ethylene-vinyl acetate resin having 18 wt % of ethylene-derived repeating units based on 100 wt % of the ethylene-vinyl acetate resin (product name: EVA1157, manufacturer: Hanwha Solutions) was used.

[0181] Evaluation Example 1: Swelling Rate

[0182] (1) Swelling rate of adhesive layer

[0183] Each of the adhesive layers of Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of width × length = 10 mm × 10 mm to prepare a sample for measuring the longitudinal swelling rate (the longitudinal length of each adhesive layer before impregnation with the electrolyte, A1 = 10 mm). The sample for measuring the longitudinal swelling rate was impregnated with the electrolyte solution, sealed, and allowed to stand at room temperature for 1 day, and then the longitudinal length (the longitudinal length of each adhesive layer after impregnation with the electrolyte solution, A2) was measured.

[0184] The electrolyte solution had the same composition as that in Example 1.

[0185] The longitudinal length (A1) of the adhesive layer before impregnation with the electrolyte solution and the longitudinal length (A2) after impregnation with the electrolyte solution were substituted (incorporated) into Equation 1 to calculate the longitudinal swelling ratio (A) of the adhesive layer.

[0186] [Equation 1]

[0187] Longitudinal swelling ratio of adhesive layer (A) (%) = (A2-A1) / A1×100

[0188] In equation 1,

[0189] A1 is the longitudinal length of the adhesive layer before being impregnated with the electrolyte solution, and

[0190] A2 is the longitudinal length of the adhesive layer after being impregnated with the electrolyte solution.

[0191] (2) Swelling rate of the base layer

[0192] Each of the substrate layers of Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of width × length = 10 mm × 10 mm to prepare a sample for measuring the longitudinal swelling rate (the longitudinal length of each substrate layer before being impregnated with the electrolyte solution, B1 = 10 mm). The sample for measuring the longitudinal swelling rate was impregnated with the electrolyte solution, sealed, allowed to stand at room temperature for 1 day, and then the length was measured (the longitudinal length of each substrate layer after being impregnated with the electrolyte solution, B2).

[0193] The electrolyte solution had the same composition as that in Example 1.

[0194] The longitudinal length ( B1 ) of the substrate layer before impregnation with the electrolyte solution and the longitudinal length ( B2 ) of the substrate layer after impregnation with the electrolyte solution are substituted into Equation 2 to calculate the longitudinal swelling ratio (B) of the substrate layer.

[0195] [Equation 2]

[0196] The longitudinal swelling ratio of the base layer (B) (%) = (B2-B1) / B1×100

[0197] In equation 2,

[0198] B1 is the longitudinal length of the substrate layer before being impregnated with the electrolyte solution,

[0199] B2 is the longitudinal length of the base layer after being impregnated with the electrolyte solution.

[0200] (3) A / B ratio

[0201] In addition, the A / B ratios were obtained from (1) and (2) of Evaluation Example 1 and are shown in Tables 1 and 2.

[0202] Evaluation Example 2: Peel Strength of Adhesive Layer

[0203] The adhesive layers of Examples 1 to 5 and the adhesive layers of Comparative Examples 1 to 3 were each prepared to a size of 100 mm×30 mm×10 μm (width×length×thickness). In addition, as a substrate to be attached, two copper substrates of width×length×thickness=150 mm×10 mm×10 μm were prepared.

[0204] Each of the adhesive layers is placed between two copper substrates to obtain a sample for measuring peel strength. The sample for measuring peel strength is pressurized for 1000 seconds at a pressure of 3.5 bar and a temperature of 50°C using an autoclave. At 25°C, one copper substrate of the pressurized sample for measuring peel strength is fixed to a general physical property analyzer (product name: TA.XT_Plus texture analyzer, manufacturer: Stable Micro System), and the other copper substrate is dragged at a speed of 60mm / min to measure the T-type peeling peel strength. The results are shown in Tables 1 and 2.

[0205] Evaluation Example 3: Gel Fraction of Adhesive Layer

[0206] Take 1g (W0) of each of the adhesive layers of Examples 1 to 5 and Comparative Examples 1 to 3 as a sample for measuring the gel fraction and place it in a 20mL vial, and add 1,2,4-trichlorobenzene (about 10mL) thereto to fully immerse the sample, and then heat it at 130°C for 2 hours or more. Filter the heated solution and separate it with a 200-mesh wire mesh. Here, the unfiltered undissolved components are washed twice with a xylene solution and dried in a hot air oven at 120°C for 12 hours. Finally, the dried undissolved component (W) is measured, and the dried undissolved component (W) is used according to Equation 3 to obtain the gel fraction. The results are shown in Tables 1 and 2.

[0207] [Equation 3]

[0208] Gel fraction (%) = (W / W0) × 100.

[0209] In Equation 3, W is the weight of the dried undissolved component; and W0 is the weight of the initial bonding layer sample, ie, 1 g.

[0210] Evaluation Example 4: Ability of Sealing Tape to Realize Three-Dimensional Shape

[0211] The rechargeable lithium battery cells of Examples 1 to 5 and Comparative Examples 1 to 3 were stored at room temperature for 1 day. Subsequently, the rechargeable lithium battery cells were disassembled and the electrode assembly was taken out to evaluate each sealing tape arranged in the gap between the outermost layer (negative electrode) of the wound type (or type) electrode assembly and its inner (lower) layer (separator) according to the following criteria. The results are shown in Tables 1 and 2.

[0212] ○: Observed Figure 2 The three-dimensional shape shown in

[0213] ×: Not observed Figure 2 The three-dimensional shape shown in FIG. 1 is separated from the wound type (or similar) electrode assembly.

[0214] Evaluation Example 5: Gap-filling ability of sealing tape

[0215] The gap filling ability of each of the sealing tapes of Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated in the following method, and the results are shown in Tables 1 and 2.

[0216] The gap filling ability of the sealing tape was evaluated by a method for evaluating the flow prevention ability of the electrode assembly, and the flow prevention ability of the electrode assembly was evaluated by a residual vibration evaluation method and a residual impact evaluation method.

[0217] (1) Residual vibration evaluation method: A vibration test was performed according to the UN38.3 standard, wherein if the power of the rechargeable lithium battery cell was not measured after the evaluation, it was judged that one terminal was disconnected.

[0218] (2) Residual impact evaluation method: After inserting a rechargeable lithium battery cell into an octagonal cylinder and rotating them, if the power of the cell is not measured after a set or predetermined period of time, it is judged that the terminal is disconnected due to flow.

[0219] The results of the two methods were judged according to the following criteria.

[0220] ○: Power was measured after residual vibration evaluation and residual shock evaluation.

[0221] ×: No power was measured after residual vibration evaluation and residual shock evaluation

[0222] Evaluation Example 6: Evaluation of flame retardancy

[0223] Each of the sealing tapes according to Examples 1 to 5 and Comparative Examples 1 to 3 was prepared into a 1 / 16 inch thick sample, and flame retardancy was evaluated as follows according to the UL94 measuring method.

[0224] First, after applying a 20 mm high flame to the sample for 10 seconds, measure its burning time (t1) and record its burning mode. Subsequently, if (for example, when) the combustion is completed after the initial (first) flame contact, measure the burning time (t2) and the luminous time (t3) after another flame contact for 10 seconds, and record its burning mode. Repeat the same test five times by using other (additional) samples of the same size to determine whether particles that generate sparks fall from it, and therefore evaluate the flame retardancy as ○ (no significant spark generation) or × (with significant spark generation).

[0225] (Table 1)

[0226]

[0227] (Table 2)

[0228]

[0229]

[0230] In Tables 1 and 2, "VA content" means the content (eg, amount) of vinyl acetate-derived repeating units based on 100 wt% of the ethylene-vinyl acetate resin.

[0231] In addition, in Table 1 and Table 2, if A / B is a decimal, the third decimal place is discarded.

[0232] Comprehensive evaluation results

[0233] Referring to evaluation examples 1 to 5, a sealing tape of one or more embodiments represented by examples 1 to 5 is arranged between the outermost layer of a wound (or similar) electrode assembly and its inner (lower) layer, in which a three-dimensional shape is achieved by impregnation with an electrolyte solution, effectively filling (filling) the gap between the cylindrical battery case and the wound (or similar) electrode assembly.

[0234] As a result, a sealing tape of one or more embodiments arranged between the outermost layer of a wound (or similar) electrode assembly and its inner (lower) layer can inhibit or reduce the rotation and / or movement of the wound (or similar) electrode assembly inside the cylindrical battery casing and prevent or reduce performance degradation of the rechargeable lithium battery cell.

[0235] In addition, referring to Evaluation Example 6, the sealing tapes of one or more embodiments represented by Examples 1 to 5, in which ethylene-vinyl acetate resin containing 5 wt % to 15 wt % of vinyl acetate-derived repeating units is applied to the base layer, exhibit excellent or suitable flame retardancy.

[0236] When describing embodiments of the inventive concept, the use of “may” refers to “one or more embodiments of the inventive concept.”

[0237] As used herein, the term "about" and similar terms are used as approximate terms rather than as terms of degree, and are intended to account for the inherent deviations of measured or calculated values ​​that will be recognized by those of ordinary skill in the art. As used herein, "about" includes the stated value and refers to the acceptable deviation range of a particular value determined by those of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0238] In addition, any numerical range described herein is intended to include all sub-ranges of the same numerical precision contained in the described range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the described minimum value 1.0 and the described maximum value 10.0 (and including the described minimum value 1.0 and the described maximum value 10.0), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described here is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify this specification and the claims to explicitly describe any sub-ranges contained in the range explicitly described here.

[0239] In the present disclosure and unless otherwise defined, "does not include one or any 'component'", "excludes one or any 'component'", "does not contain 'component'", etc. means that the 'component' is not added, selected or used as a component in the chemical formula / composition / structure, but due to other impurities and / or external factors, less than the appropriate amount of the 'component' may still be included.

[0240] Here, unless otherwise defined, steps, tasks, or actions listed in a particular order do not necessarily mean that the invention or claims require that particular order. That is, unless the steps, tasks, or actions of a method (e.g., a method claim) actually describe an order, the steps, tasks, or actions should not be interpreted as a general rule requiring an order.

[0241] Any suitable hardware, firmware (e.g., an application specific integrated circuit), software, or a combination of software, firmware, and hardware may be used to implement a battery management system (BMS) device and / or any other related device or component according to an embodiment of the present invention described herein. For example, the various components of the device may be formed on an integrated circuit (IC) chip or on separate IC chips. In addition, the various components of the device may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a substrate. In addition, the various components of the device may be processes or threads that execute computer program instructions and interact with other system components to perform the various functions described herein, running on one or more processors in one or more computing devices. The computer program instructions are stored in a memory, which may be implemented as a computing device using a standard memory device (such as a random access memory (RAM) as an example). The computer program instructions may also be stored in other non-temporary computer-readable media (such as a CD-ROM, a flash drive, etc. as an example). In addition, it should be appreciated by those skilled in the art that, without departing from the scope of the present disclosure, the functions of various computing devices may be combined or integrated into a single computing device, or the functions of a particular computing device may be distributed across one or more other computing devices.

[0242] While the disclosure has been described in conjunction with what are presently considered to be practical example embodiments, it will be understood that the disclosure is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents.

[0243] <Reference Numbers>

[0244] 100: Rechargeable lithium battery

[0245] 10: Positive electrode 20: Negative electrode

[0246] 30: Diaphragm

[0247] 50: housing 60: sealing member

[0248] 200: Sealing tape

[0249] 210: Base layer 220: Adhesive layer.

Claims

1. A sealing tape, the sealing tape include: Basal layer; as well as an adhesive layer, on the base layer, wherein the base layer comprises ethylene-vinyl acetate resin, and the ethylene-vinyl acetate resin comprises repeating units derived from ethylene and repeating units derived from vinyl acetate, The amount of the vinyl acetate-derived repeating unit is 5 wt % to 15 wt % based on 100 wt % of the ethylene-vinyl acetate resin, and The sealing tape is used for a rechargeable lithium battery.

2. The sealing tape according to claim 1, in, The base layer and the adhesive layer have different longitudinal swelling rates in response to impregnation with an electrolyte solution.

3. The sealing tape according to claim 1, in, According to Equation 1, the adhesive layer has a longitudinal swelling ratio A of 110% to 150%, According to Equation 2, the base layer has a longitudinal swelling ratio B of 100% to 130%, The longitudinal swelling rate A of the adhesive layer is greater than the longitudinal swelling rate B of the base layer: [Equation 1] The longitudinal swelling ratio of the adhesive layer is A = (A2-A1) / A1×100% Where, in equation 1, A1 is the longitudinal length of the adhesive layer before being impregnated with the electrolyte solution, A2 is the longitudinal length of the adhesive layer after being impregnated with the electrolyte solution; [Equation 2] The longitudinal swelling ratio of the base layer B = (B2-B1) / B1×100% Where, in equation 2, B1 is the longitudinal length of the substrate layer before being impregnated with the electrolyte solution, and B2 is the longitudinal length of the base layer after being impregnated with the electrolyte solution.

4. The sealing tape according to claim 3, in, A ratio A / B of a longitudinal swelling ratio A of the adhesive layer to a longitudinal swelling ratio B of the base layer is greater than 1 and less than or equal to 1.

15.

5. The sealing tape according to claim 1, in, The gel fraction of the adhesive layer is greater than or equal to 70 wt %.

6. The sealing tape according to claim 1, in, The adhesive layer has a T-peel peel strength of greater than or equal to 60 gf / cm measured at a peeling speed of 60 mm / min and a peeling angle of 180 degrees with respect to a substrate to be attached.

7. The sealing tape according to claim 1, in, The adhesive layer includes an acrylic adhesive.

8. The sealing tape according to claim 7, in, The acrylic adhesive is a copolymer of 2-ethylhexyl acrylate and 4-hydroxybutyl acrylate cross-linked with an isocyanate cross-linking agent.

9. A rechargeable lithium battery, wherein the rechargeable lithium battery include: Cylindrical battery case; a wound electrode assembly in the cylindrical battery case; The sealing tape according to claim 1, between the outermost layer of the wound electrode assembly and the inner layer of the wound electrode assembly; and An electrolyte solution is used to impregnate the wound electrode assembly and the sealing tape.

10. The rechargeable lithium battery according to claim 9, in, The wound type electrode assembly is a stacked body in which a positive electrode, a separator, and a negative electrode are sequentially stacked and wound in such a manner that the negative electrode is the outermost layer.

11. The rechargeable lithium battery according to claim 9, in, The length of the sealing tape is 0.8 to 1.5 times the circumference of the wound electrode assembly.

12. The rechargeable lithium battery according to claim 9, in, A portion of the sealing tape is exposed to the outside of the outermost layer of the wound type electrode assembly.

13. The rechargeable lithium battery according to claim 9, in, A portion of the sealing tape is between the outermost layer of the wound electrode assembly and the inner layer of the wound electrode assembly, and a remaining portion of the sealing tape is between the outermost layer of the wound electrode assembly and the cylindrical battery case.

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