Composite substrate for rechargeable lithium battery and rechargeable lithium battery including the same

Abstract

Disclosed are a composite substrate and a rechargeable lithium battery including the same. The composite substrate includes a support layer including an additive, a first metal layer on a top surface of the support layer, and a second metal layer on a bottom surface of the support layer. The additive comprises at least one of ceramic particles and fire extinguishing liquid capsules. An amount of the additive is from about 1 wt% to about 20 wt% relative to a total weight of the support layer.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0060224, filed on May 8, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a composite substrate for a rechargeable lithium battery, and to a rechargeable lithium battery including the composite substrate. Background Technology

[0003] With the increasing use of battery-powered electronic devices (such as mobile phones, laptops, and electric vehicles), the demand for rechargeable batteries with high energy density and high capacity is increasing.

[0004] Rechargeable lithium batteries typically include a positive electrode, a negative electrode, and an electrolyte. The positive and negative electrodes contain active materials that can insert and extract lithium ions, and generate electrical energy through redox reactions when lithium ions are inserted and extracted. Summary of the Invention

[0005] An exemplary embodiment of this disclosure provides a composite substrate capable of preventing, suppressing, or blocking internal short circuits.

[0006] An exemplary embodiment of this disclosure provides a rechargeable lithium battery capable of preventing, suppressing, or stopping fires.

[0007] According to an exemplary embodiment of this disclosure, a composite substrate for a rechargeable lithium battery may include: a support layer including an additive; a first metal layer on a top surface of the support layer; and a second metal layer on a bottom surface of the support layer. The additive may include at least one of ceramic particles and fire extinguishing liquid capsules. The amount of the additive may be from about 1 wt% to about 20 wt% relative to the total weight of the support layer.

[0008] According to exemplary embodiments of this disclosure, a rechargeable lithium battery may include the composite substrate of this disclosure. Attached Figure Description

[0009] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown.

[0010] Figures 2 to 5 A simplified diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown.

[0011] Figure 6 A cross-sectional view is shown illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure.

[0012] Figure 7 and Figure 8 A cross-sectional view of a composite substrate according to an example embodiment of the present disclosure is shown. Detailed Implementation

[0013] To fully understand the structure and effects of this disclosure, some exemplary embodiments of the disclosure will be described with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the following exemplary embodiments and can be implemented in various forms. Rather, the exemplary embodiments are provided merely to disclose this disclosure and to enable those skilled in the art to fully understand its scope.

[0014] In this specification, it will be understood that when an element is referred to as being "on" another element, the element may be directly on said other element, or an intervening element may be present between them. In the accompanying drawings, the thickness of some components is exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, the same reference numerals denote the same elements.

[0015] Unless otherwise specifically indicated in this specification, singular expressions may include plural expressions. Furthermore, unless otherwise specifically indicated, the phrase "A or B" may mean "A but not B," "B but not A," and "A and B." The terms "including / comprise" and / or variations thereof as used in this specification do not exclude the presence or addition of one or more other components.

[0016] As used herein, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0017] Unless otherwise specifically defined in this description, particle size can be the average particle size. Furthermore, particle size refers to the average particle size (Dsize) that constitutes approximately 50% of the cumulative volume in the particle size distribution. 50 Average particle size (D) 50 The particle size can be measured using methods widely known to those skilled in the art, such as by a particle size analyzer, transmission electron microscopy (TEM) images, or scanning electron microscopy (SEM) images. Alternatively, data analysis can be performed using a dynamic light scattering measurement device to count the number of particles for each particle size range, from which the average particle size (D) can then be calculated. 50 The average particle size (D) can be measured using laser scattering, unlike other methods. 50 In the laser scattering method, target particles are distributed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT3000, commercially available from Microtrac). The particles are irradiated with 28kHz ultrasound at a power of 60W, and the average particle size (D) is then calculated within the measuring device using a 50% standard particle size distribution. 50 ).

[0018] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical value includes a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range, such as increments of 0.1%.

[0019] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure is shown. (Refer to...) Figure 1 A rechargeable lithium battery may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte ELL.

[0020] The positive electrode 10 and the negative electrode 20 can be spaced apart from each other by a diaphragm 30. The diaphragm 30 can be located between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20 and the diaphragm 30 can be in contact with the electrolyte ELL. The positive electrode 10, the negative electrode 20 and the diaphragm 30 can be immersed in the electrolyte ELL.

[0021] The electrolyte ELL can be or includes a medium through which lithium ions are transferred between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, lithium ions can move toward one of the positive electrode 10 and the negative electrode 20 through the membrane 30.

[0022] Positive electrode 10 The positive electrode 10 for a rechargeable lithium battery may include a current collector COL1 and a positive electrode active material layer AML1 formed on the current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material, and may also include a binder and / or a conductive material.

[0023] For example, the positive electrode 10 may also include additives that can constitute a sacrificial positive electrode.

[0024] The amount of positive electrode active material relative to 100 wt% of the positive electrode active material layer AML1 may be from about 90 wt% to about 99.5 wt%. The amount of each or at least one of the binder and conductive material relative to 100 wt% of the positive electrode active material layer AML1 may be from about 0.5 wt% to about 5 wt%.

[0025] The binder can improve the adhesion between the positive electrode active material particles and also improve the adhesion of the positive electrode active material to the current collector COL1. The binder may include, for example, at least one of 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 nylon, but this disclosure is not limited thereto.

[0026] Conductive materials can include any suitable conductive material that provides conductivity to the electrodes without causing chemical changes in the battery. Conductive materials can include, for example: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal powders or fibers containing one or more of copper, nickel, aluminum, and silver; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0027] Aluminum (Al) can be used to form current collector COL1, but this disclosure is not limited thereto.

[0028] Positive electrode active material The positive electrode active material in the positive electrode active material layer AML1 may contain compounds that can reversibly insert and extract lithium (e.g., lithiation intercalation compounds). For example, the positive electrode active material may include at least one composite oxide comprising lithium and a metal, wherein the metal is or includes at least one of cobalt, manganese, nickel, and combinations thereof.

[0029] The composite oxide may include lithium transition metal composite oxides, such as lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free lithium nickel manganese oxides, and combinations thereof, at least one of these.

[0030] For example, the positive electrode active material may include a compound represented by one of the following 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); Lia 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 DG 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 b O2 (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); Li a FePO4 (where 0.90≤a≤1.8).

[0031] In the above chemical formula, A is or includes at least one of Ni, Co, Mn and combinations thereof; X is or includes at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof; D is or includes at least one of O, F, S, P and combinations thereof; G is or includes at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and combinations thereof; and L 1 It is or includes at least one of Mn, Al and combinations thereof.

[0032] For example, the positive electrode active material can be or includes a high-nickel positive electrode active material, wherein the nickel content of the high-nickel positive electrode active material is 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% relative to 100 mol% of the lithium transition metal complex oxide. High-nickel positive electrode active materials can achieve high capacity and therefore can be used in high-capacity and high-density rechargeable lithium batteries.

[0033] negative electrode 20 The negative electrode 20 for a rechargeable lithium battery may include a current collector COL2 and a negative electrode active material layer AML2 located on the current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material and may also include a binder and / or a conductive material.

[0034] For example, the negative electrode active material layer AML2 may include about 90 wt% to about 99 wt% of negative electrode active material, about 0.5 wt% to about 5 wt% of binder, and about 0 wt% to about 5 wt% of conductive material.

[0035] The binder can improve the adhesion between the particles of the negative electrode active material and also improve the adhesion of the negative electrode active material to the current collector COL2. The binder can include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0036] Non-aqueous adhesives may include at least one of polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, and combinations thereof.

[0037] Waterborne adhesives may include at least one of the following: styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomers, polyethylene oxide, polyvinylpyrrolidone, polyepoxychlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0038] When an aqueous binder constitutes a negative electrode binder, it may also include a cellulose compound capable of providing viscosity. Cellulose compounds may include one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts. Alkali metals may include Na, K, or Li.

[0039] The dry binder may include a fibrillatable polymer material, for example, at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene copolymer, polyethylene oxide, and combinations thereof.

[0040] A conductive material may be included to provide conductivity to the electrode, and any suitable conductive material that does not cause chemical changes in the battery may constitute the conductive material in the battery. For example, the conductive material may include: carbonaceous materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal powders or metal fibers including one or more of copper, nickel, aluminum, and silver; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0041] The current collector COL2 may include at least one of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0042] Negative electrode active material The negative electrode active material in the negative electrode active material layer AML2 may include a material that can reversibly intercalate and deintercalate lithium ions, lithium metal, a lithium metal alloy, a material that can be doped and undoped with lithium, or a transition metal oxide.

[0043] The material that can reversibly intercalate and deintercalate lithium ions may include carbonaceous negative electrode active materials, for example, crystalline carbon, amorphous carbon, or combinations thereof. For example, crystalline carbon may include graphite, such as at least one of natural graphite or artificial graphite in a shapeless, sheet-like, flaky, spherical, and fibrous form, and amorphous carbon may include at least one of soft carbon, hard carbon, mesophase pitch carbon, and calcined coke.

[0044] The lithium metal alloy may include an alloy of lithium and a metal, and the metal is or includes at least one of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0045] The material that can be doped and undoped with lithium may include Si-based negative electrode active materials or Sn-based negative electrode active materials. Si-based negative electrode active materials may include silicon, silicon-carbon composites, SiO x (where 0 < x < 2), Si-Q alloys (where Q is 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, or combinations thereof), and combinations thereof. Sn-based negative electrode active materials may include Sn, SnO2, Sn-based alloys, and combinations thereof.

[0046] Silicon-carbon composites can be or include composites of silicon and amorphous carbon. According to example embodiments, a silicon-carbon composite can have a structure in which amorphous carbon is coated on the surface of silicon particles. For example, a silicon-carbon composite can include secondary particles (cores) assembled therein from primary silicon particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particles. Amorphous carbon can also be located between the primary silicon particles; for example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can be dispersed within an amorphous carbon matrix.

[0047] Silicon-carbon composites may also include crystalline carbon. For example, a silicon-carbon composite may include a core comprising crystalline carbon and silicon particles, and may also include an amorphous carbon coating layer on the surface of the core.

[0048] Si-based or Sn-based negative electrode active materials can be used in combination with carbon-based negative electrode active materials.

[0049] Diaphragm 30 Depending on the type of rechargeable lithium battery, the separator 30 may be located between the positive electrode 10 and the negative electrode 20. The separator 30 may include one or more of polyethylene, polypropylene, and polyvinylidene fluoride, and may have multiple layers of them, such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polypropylene triple-layer separator, and a polypropylene / polypropylene / polypropylene triple-layer separator.

[0050] The diaphragm 30 may include a porous substrate and a coating layer on one or opposite surfaces of the porous substrate, the coating layer comprising an organic material, an inorganic material, or a combination thereof.

[0051] The porous substrate may be or include a polymer layer, which includes polyolefins (including at least one of 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, Teflon and polytetrafluoroethylene, or may be or include copolymers or mixtures comprising two or more of the above materials.

[0052] Organic materials may include polyvinylidene fluoride copolymers or (meth)acrylic acid copolymers.

[0053] Inorganic materials may include inorganic particles, which include at least one of Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but this disclosure is not limited thereto.

[0054] Organic and inorganic materials can be mixed in a coating layer, or they can exist as a stack of coating layers including organic materials and coating layers including inorganic materials.

[0055] Electrolyte ELL Electrolytes (ELLs) used in rechargeable lithium batteries may include non-aqueous organic solvents and lithium salts.

[0056] Non-aqueous organic solvents can serve as media for transporting ions that participate in the electrochemical reactions of a battery.

[0057] Non-aqueous organic solvents may include at least one of carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, and combinations thereof.

[0058] Carbonate solvents may include at least one of 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 butyl carbonate (BC).

[0059] Ester solvents may include at least one of methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, valproic acid lactone, and caprolactone.

[0060] Ether solvents may include at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran. Ketone solvents may include cyclohexanone. Alcohol solvents may include ethanol or isopropanol. Aprotic solvents may include: nitriles, such as R-CN (wherein R is a hydrocarbon group having a C2 to C20 straight-chain, branched, or cyclic structure, and may include double bonds, aromatic rings, or ether groups); amides, such as dimethylformamide; dioxolane, such as 1,3-dioxolane or 1,4-dioxolane; or sulfolane.

[0061] Non-aqueous organic solvents can be used alone or in mixtures of two or more substances.

[0062] Furthermore, when using carbonate solvents, 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.

[0063] Lithium salts can be or include materials dissolved in non-aqueous organic solvents to form a supply source of lithium ions in the battery, and serve to enable the basic operation of the rechargeable lithium battery and facilitate the movement of lithium ions between the positive and negative electrodes. Lithium salts can include, for example, 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 At least one of the following: (SO2) (where x and y are integers between 1 and 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0064] Rechargeable lithium batteries Based on their shape, rechargeable lithium batteries can be classified into cylindrical, prismatic, pouch, and coin-shaped types. Figures 2 to 5 A simplified diagram illustrating a rechargeable lithium battery according to an example embodiment is shown. Figure 2 A cylindrical battery is shown. Figure 3 A prismatic battery is shown, and Figure 4 and Figure 5 A pouch-type battery is shown. (See reference) Figures 2 to 5 The rechargeable lithium battery 100 may include an electrode assembly 40 with a separator 30 disposed between a positive electrode 10 and a negative electrode 20, and may also include a housing 50 therein housing the electrode assembly 40. The positive electrode 10, negative electrode 20, and separator 30 may be immersed in an electrolyte (not shown). Figure 2 As shown, the rechargeable lithium battery 100 may include a sealing member 60 of the sealed housing 50. Furthermore, as... Figure 3 As shown, the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12, a negative electrode lead connector 21, and a negative electrode terminal 22. Figure 4 and Figure 5 As shown, the rechargeable lithium battery 100 may include Figure 5 The electrode terminals 70 shown are Figure 4 The positive electrode terminal 71 and negative electrode terminal 72 shown herein constitute an electrical path for guiding the current generated in the electrode assembly 40 to the outside of the rechargeable lithium battery 100.

[0065] In the following example embodiments, references to the above will be omitted. Figures 1 to 5 The technical features of the rechargeable lithium battery discussed are described in detail, and the differences between them are discussed in detail.

[0066] Figure 6 A cross-sectional view is shown illustrating a rechargeable lithium battery according to an example embodiment of the present disclosure. (Refer to...) Figure 6 A single dual-cell battery may include a composite substrate CPS, a first cell CEL1 on one surface of the composite substrate CPS, and a second cell CEL2 on the other surface of the composite substrate CPS. A single dual-cell battery may be composed of... Figure 6 It consists of a first battery cell CEL1, a second battery cell CEL2, and a composite substrate CPS. Figure 6 The first battery cell CEL1, the second battery cell CEL2, and the composite substrate CPS can constitute the above-mentioned reference. Figures 2 to 5 Electrode assembly 40 under discussion.

[0067] Each or at least one of the first battery cell CEL1 and the second battery cell CEL2 may include a first active material layer ACT1, a separator 30, a second active material layer ACT2, and a metal substrate MES. The first active material layer ACT1 may be disposed on a composite substrate CPS. The second active material layer ACT2 may be spaced apart from the first active material layer ACT1 by the separator 30. The metal substrate MES may be disposed on the second active material layer ACT2.

[0068] The first active substance layer ACT1 may be or includes the above reference. Figure 1 The discussion focuses on one of the positive electrode active material layer AML1 and the negative electrode active material layer AML2. The second active material layer ACT2 may be or include the above-mentioned reference. Figure 1 The discussion focuses on the other of the positive electrode active material layer AML1 and the negative electrode active material layer AML2. In exemplary embodiments of this disclosure, the first active material layer ACT1 may be or include the positive electrode active material layer AML1, and the second active material layer ACT2 may be or include the negative electrode active material layer AML2. The metal substrate MES may be or include the above-mentioned... Figure 1 The current collectors COL1 or COL2 are discussed.

[0069] The composite substrate CPS may include a support layer SPL, and may further include a first metal layer MEL1 and a second metal layer MEL2 located on opposite surfaces of the support layer SPL. The first metal layer MEL1 of the composite substrate CPS may be in contact with the first active material layer ACT1 of the first battery cell CEL1. The second metal layer MEL2 of the composite substrate CPS may be in contact with the first active material layer ACT1 of the second battery cell CEL2. Each or at least one of the first metal layer MEL1 and the second metal layer MEL2 of the composite substrate CPS may correspond to the above reference. Figure 1 One of the current collectors COL1 and COL2 is being discussed.

[0070] The support layer SPL may comprise a polymer membrane. For example, the support layer SPL may comprise at least one of a polyethylene membrane, a polypropylene membrane, a polyvinylidene chloride membrane, and multilayer membranes comprising combinations thereof. The support layer SPL may have desired or improved ion permeability and excellent mechanical strength.

[0071] Each or at least one of the first metal layer MEL1 and the second metal layer MEL2 may include at least one of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, iron, iron alloy, silver, and silver alloy.

[0072] In an example embodiment, each or at least one of the first metal layer MEL1 and the second metal layer MEL2 may have a thickness greater than about 0 μm and equal to or less than about 5 μm. For example, each or at least one of the first metal layer MEL1 and the second metal layer MEL2 may have a thickness of about 200 nm to about 5 μm. The support layer SPL may have a thickness of about 2 μm to about 10 μm. For example, the support layer SPL may have a thickness of about 3 μm to about 10 μm. The thickness of the support layer SPL may be greater than the thickness of each or at least one of the first metal layer MEL1 and the second metal layer MEL2.

[0073] The composite substrate CPS may have a first end ENP1 at one end. The metal substrate MES of the first battery cell CEL1 may include a second end ENP2 at one end. The metal substrate MES of the second battery cell CEL2 may include a third end ENP3 at one end.

[0074] The first connector TAB1 may be located on the first end ENP1 of the composite substrate CPS. The first connector TAB1 may include a first connecting portion UPP1, a second connecting portion UPP2, and an extension portion EXP. The first connecting portion UPP1 may contact the first metal layer MEL1 of the composite substrate CPS. The second connecting portion UPP2 may contact the second metal layer MEL2 of the composite substrate CPS. The extension portion EXP may connect the first connecting portion UPP1 and the second connecting portion UPP2 to each other. The extension portion EXP may extend horizontally from the first end ENP1 in a first direction D1.

[0075] The first connector TAB1 can electrically connect the first metal layer MEL1 and the second metal layer MEL2 to each other. The first connector TAB1 can be configured to apply a voltage to both the first metal layer MEL1 and the second metal layer MEL2.

[0076] The second terminal block TAB2 can be disposed on the second end ENP2 of the metal substrate MES. The second terminal block TAB2 can be configured to apply voltage to the metal substrate MES of the first battery cell CEL1. The third terminal block TAB3 can be disposed on the third end ENP3 of the metal substrate MES. The third terminal block TAB3 can be configured to apply voltage to the metal substrate MES of the second battery cell CEL2.

[0077] The first connector TAB1 can be configured as shown above. Figures 2 to 5 One of the positive electrode terminal and negative electrode terminal (or positive electrode lead terminal and negative electrode lead terminal) of the terminal blocks 70 / 71 / 72 discussed. The second terminal block TAB2 and the third terminal block TAB3 can constitute the above-mentioned reference. Figures 2 to 5 The other of the positive electrode terminal block and negative electrode terminal block (or positive electrode lead terminal block and negative electrode lead terminal block) discussed.

[0078] Figure 7 and Figure 8 A cross-sectional view of a composite substrate according to an example embodiment of the present disclosure is shown.

[0079] Reference Figure 7The support layer SPL may include a polymer layer POL and an additive ADD dispersed in the polymer layer POL. The polymer layer POL may include a polymer film as discussed above. The additive ADD may be or include particles. The particles may include heat-absorbing materials. For example, the additive ADD may be or include ceramic particles. The ceramic particles may include at least one of pseudoboehmite (or "false boehmite"), alumina (Al2O3), silica (SiO2), titanium dioxide (TiO2), tin oxide (SnO2), cerium oxide (CeO2), magnesium oxide (MgO), nickel oxide (NiO), calcium oxide (CaO), gallium oxide (Ga2O3), zinc oxide (ZnO), zirconium dioxide (ZrO2), yttrium oxide (Y2O3), strontium titanate (SrTiO3), barium titanate (BaTiO3), magnesium hydroxide (Mg(OH)2), and boehmite.

[0080] The ceramic particles in the support layer SPL can absorb heat. The temperature of the portion of the polymer layer POL surrounding the ceramic particles can rise rapidly, causing the polymer layer POL to melt. This can accelerate the rate at which internal short circuits are prevented or suppressed.

[0081] The ceramic particles can have an average particle size (D) ranging from about 0.07 μm to about 3 μm, for example, from about 0.1 μm to about 2 μm or from about 0.5 μm to about 1.5 μm. 50 The average particle size (D) of ceramic particles 90 It can be in the range of approximately 2 μm to approximately 5 μm, for example, approximately 4 μm to approximately 4.5 μm. 50 Or D 90 It can be defined as the particle size that corresponds to 50% or 90% of the cumulative volume from the smaller particle size side in the particle size distribution of ceramic particles. When the size of ceramic particles falls within the above range, internal short circuits can be effectively prevented, suppressed, or blocked, and battery fires can be prevented, suppressed, or blocked.

[0082] Reference Figure 8 The support layer SPL may include a polymer layer POL and an additive ADD dispersed in the polymer layer POL. In an example embodiment, the additive ADD may be or include a capsule CAS (also known as a "fire extinguishing liquid capsule CAS"). The capsule CAS may include a core COR and a shell SHL. The shell SHL may be located on the surface of the core COR. For example, the capsule CAS may be or include a fire extinguishing liquid capsule.

[0083] The core COR of a fire extinguishing liquid capsule (CAS) can include fire extinguishing liquid. Fire extinguishing liquid can include at least one of halogen compounds, solid aerosol fire extinguishing materials, gas generating agents, and fluoroketone compounds. Halogen compounds can be defined as compounds in which some or all of the hydrogen atoms in an aliphatic hydrocarbon molecule are replaced by a halogen element (F, Cl, Br, I). For example, halogen compounds can include at least one of bromomethane (CH3Br), iodomethane (CH3I), bromochloromethane (CH2BrCl), dibromodifluoromethane (CF2Br2), bromochlorodifluoromethane (CF2BrCl), bromotrifluoromethane (CF3Br), carbon tetrachloride (CCl4), and dibromotetrafluoroethane (C2F4Br2). For example, solid aerosol fire extinguishing materials can include at least one of potassium nitrate (KNO3), potassium perchlorate (KClO4), barium nitrate (Ba(NO3)2), and resin. Gas generating agents can produce inert gases such as carbon dioxide through thermal decomposition. For example, the gas generating agent may include at least one of potassium bicarbonate (KHCO3), sodium bicarbonate (NaHCO3), and manganese carbonate (MnCO3). For example, the fluoroketone compound may include at least one of hydrofluorocarbons, hydrochlorofluorocarbons, perfluorocarbons, perfluoropolyethers, hydrofluoroethers, hydrofluoropolyethers, chlorofluorocarbons, bromofluorocarbons, bromochlorofluorocarbons, iodofluorocarbons, and hydrobromofluorocarbons.

[0084] The shell SHL of the fire extinguishing liquid capsule may include a polymer. For example, the polymer may include at least one of polyethylene terephthalate, polyethylene, polypropylene, polymethyl methacrylate, poly(1-butene), and polyimide.

[0085] The polymer can be melted. The melting temperature can be in the range of about 100°C to about 260°C. For example, the melting temperature can be in the range of about 100°C to about 250°C, or about 150°C to about 250°C. The capsule CAS can have a granular shape and / or a tabular shape.

[0086] Capsule CAS can have a size of about 3 μm to about 10 μm. For example, capsule CAS can have a size of about 3 μm to about 8 μm. When capsule CAS has a granular shape, the size of capsule CAS can be defined as particle size. In an example embodiment, particle size can be represented by the diameter measured by randomly selecting about 30 capsule CAS from an electron microscope image of capsule CAS.

[0087] For example, the capsule CAS can have a long axis and a short axis. The long axis can have a length of about 3 μm to about 10 μm. The short axis can have a length of about 0.5 μm to about 2 μm.

[0088] The total thickness of the shell SHL can be approximately 30% to approximately 50% of the size of the fire extinguishing liquid capsule CAS. For example, the total thickness of the shell SHL can be approximately 50% of the size of the fire extinguishing liquid capsule CAS. When observed in a cross-section of the fire extinguishing liquid capsule CAS, the total thickness of the shell SHL can be defined as the difference in particle size between the fire extinguishing liquid capsule CAS and the core COR. For example, the particle size of the fire extinguishing liquid capsule CAS and the particle size of the core COR can be respectively referred to as the diameter of the capsule CAS and the diameter of the core COR, measured by randomly selecting approximately 30 cross-sections of capsule CAS from an electron microscope image of the cross-section of the capsule CAS. For example, the total thickness of the shell SHL can be in the range of approximately 0.9 μm to approximately 5 μm, or approximately 1.5 μm to approximately 4 μm.

[0089] When the size of the capsule CAS and the thickness of the shell SHL fall within the above range, it can effectively prevent, suppress or stop internal short circuits and battery cell fires.

[0090] When heat is applied to the capsule CAS, the shell SHL can melt and extinguishing liquid can be released from the core COR. The extinguishing liquid can penetrate the metal studs of the rechargeable lithium battery and the interior of the rechargeable lithium battery (first active material layer ACT1, second active material layer ACT2, first metal layer MEL1, and second metal layer MEL2). Therefore, it is possible to effectively prevent, suppress, or stop internal contact, internal short circuits, and battery ignition.

[0091] Return to reference Figure 7 and Figure 8 The amount of additive ADD relative to the total weight of the support layer SPL can be from about 1 wt% to about 20 wt%. For example, the amount of additive ADD relative to the total weight of the support layer SPL can be from about 2 wt% to about 20 wt%, from about 3 wt% to about 15 wt%, or from about 8 wt% to about 12 wt%.

[0092] The area of ​​the additive ADD can be the unit cross-sectional area (1 cm²) of the support layer SPL. 2 Approximately 1% to approximately 10% of the total area. In this example, this is relative to the unit cross-sectional area (1 cm²) of the support layer SPL. 2 The area of ​​the additive ADD can be approximately 0.01 cm². 2 With approximately 0.1cm 2 Between. For example, the area of ​​additive ADD can be within the unit cross-sectional area (1 cm²) of the support layer SPL. 2 It is between approximately 3% and approximately 7% of the total area. In this example, it is relative to the unit cross-sectional area (1 cm²) of the support layer SPL. 2 The area of ​​the additive ADD can be approximately 0.03 cm². 2 Approximately 0.07cm 2 between.

[0093] The amount and area of ​​the additive ADD can be measured using SEM-EDS (scanning electron microscopy-energy dispersive X-ray spectroscopy). In addition to SEM-EDS, inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectrometry (ICP-OES) can be used to measure the amount and area of ​​the additive ADD.

[0094] When the amount and area of ​​the additive ADD fall within any of the above ranges, the composite substrate CPS can provide a cell with improved stability.

[0095] The following description will focus on some exemplary embodiments of this disclosure. These exemplary embodiments are provided to aid in understanding this disclosure and are not intended to limit its scope.

[0096] Example 1 A rechargeable lithium battery is fabricated comprising a composite substrate for use in a rechargeable lithium battery. The composite substrate includes a support layer containing ceramic particles, a first metal layer on the top surface of the support layer, and a second metal layer on the bottom surface of the support layer. The ceramic particles comprise boehmite. The amount of ceramic particles is 10 wt% relative to the total weight of the support layer. The average particle size D of the ceramic particles is... 50 and D 90 The sizes are 1μm and 4μm, respectively.

[0097] Example 2 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that the amount of ceramic particles was 5 wt% relative to the total weight of the support layer.

[0098] Example 3 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that the amount of ceramic particles was 3 wt% relative to the total weight of the support layer.

[0099] Example 4 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that the amount of ceramic particles was 20 wt% relative to the total weight of the support layer.

[0100] Example 5 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, the difference being the D of the ceramic particles. 50 and D 90 The sizes are 3μm and 5μm, respectively.

[0101] Example 6 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that alumina (Al2O3) was used instead of boehmite as the ceramic particles.

[0102] Example 7 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that magnesium hydroxide (Mg(OH)2) was used instead of boehmite as the ceramic particles.

[0103] Example 8 A rechargeable lithium battery is prepared comprising a composite substrate for use in a rechargeable lithium battery. The composite substrate includes a support layer containing a fire extinguishing liquid capsule, a first metal layer on the top surface of the support layer, and a second metal layer on the bottom surface of the support layer. The fire extinguishing liquid capsule includes a core and a shell. The core comprises bromomethane (CH3Br). The shell comprises polypropylene (PP). The amount of the fire extinguishing liquid capsule relative to the total weight of the support layer is 10 wt%. The particle size of the fire extinguishing liquid capsule is 6 μm, and the total thickness of the shell is 3 μm.

[0104] Example 9 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 8, except that the core of the fire extinguishing liquid capsule comprises a solid aerosol fire extinguishing material, and the shell of the fire extinguishing material comprises polyethylene terephthalate (PET).

[0105] Example 10 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 8, except that the particle size of the fire extinguishing liquid capsule was 10 μm and the total thickness of the shell was 4 μm.

[0106] Comparison Example 1 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that the composite substrate did not contain ceramic particles.

[0107] Comparison Example 2 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, except that the amount of ceramic particles was 25 wt% relative to the total weight of the support layer.

[0108] Comparison Example 3 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, the difference being the D of the ceramic particles. 50 and D90 The values ​​are 0.01 μm and 0.03 μm, respectively.

[0109] Compare Example 4 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, the difference being the D of the ceramic particles. 50 and D 90 The sizes are 0.05 μm and 1 μm, respectively.

[0110] Compare Example 5 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 1, the difference being the D of the ceramic particles. 50 and D 90 They are 5μm and 9μm respectively.

[0111] Comparison Example 6 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 8, except that the particle size of the fire extinguishing liquid capsule was 1 μm and the total thickness of the shell was 0.1 μm.

[0112] Compare Example 7 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 8, except that the particle size of the fire extinguishing liquid capsule was 2 μm and the total thickness of the shell was 0.2 μm.

[0113] Compare Example 8 A rechargeable lithium battery comprising a composite substrate was prepared using the same method as in Example 8, except that the particle size of the fire extinguishing liquid capsule was 10 μm and the total thickness of the shell was 6 μm.

[0114] Experimental Example: Measurement of Voltage Drop The measurements included the voltage drop of the single-layer pouch cell on the composite substrate according to the above example embodiments and comparative examples. The voltage drop of the example embodiments and comparative examples was measured under the same conditions using a nail penetration tester (HS-3900N, commercially available from Duocom Industries, Inc.). Voltage drop can refer to the difference between the initial voltage and the single-cell voltage measured by the measuring device when the pouch cell is penetrated by a nail. The results are listed in Table 1.

[0115] [Table 1]

[0116]

[0117] Referring to Table 1, the voltage drop of the pouch cells according to Example Examples 1 to 7 is less than that of the pouch cells according to Comparative Examples 1 to 5. For example, the composite substrates according to Comparative Examples 1 to 5 have a large short-circuit area and high electron flow, and therefore have a high potential for heat generation and thermal runaway. In contrast, the composite substrates according to Example Examples 1 to 7 are effective against internal short circuits.

[0118] The voltage drop of the pouch cell according to Example Embodiments 8 to 10 is less than the voltage drop of the pouch cell according to Comparative Examples 1 and 6 to 8. For example, compared to the composite substrates according to Comparative Examples 1 and 6 to 8, the composite substrates according to Example Embodiments 8 to 10 are effective against internal short circuits.

[0119] The composite substrate according to this disclosure can prevent, suppress, or block internal short circuits. Therefore, the composite substrate can maintain battery performance and provide stability to the battery. The rechargeable lithium battery including the composite substrate of this disclosure can have improved stability and consistent performance.

[0120] Although some exemplary embodiments of the present disclosure have been discussed with reference to the accompanying drawings, it will be understood that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure. It will be apparent to those skilled in the art that various substitutions, modifications, and alterations may be made therein without departing from the scope and spirit of the present disclosure.

Claims

1. A composite substrate for a rechargeable lithium battery, the composite substrate comprising: Support layer, including additives; A first metal layer is on the top surface of the support layer; as well as The second metal layer is located on the bottom surface of the support layer. The additive includes at least one of ceramic particles and fire extinguishing liquid capsules, and The amount of the additive is 1 wt% to 20 wt% relative to the total weight of the support layer.

2. The composite substrate according to claim 1, wherein, The ceramic particles include at least one of the following: boehmite, alumina, silicon dioxide, titanium dioxide, tin oxide, cerium oxide, magnesium oxide, nickel oxide, calcium oxide, gallium oxide, zinc oxide, zirconium dioxide, yttrium oxide, strontium titanate, barium titanate, magnesium hydroxide, and boehmite.

3. The composite substrate according to claim 1, wherein, The average particle size D of the ceramic particles 50 Within the range of 0.07 μm to 3 μm.

4. The composite substrate according to claim 1, wherein, The average particle size D of the ceramic particles 90 Within the range of 2μm to 5μm, and D 90 It is the particle size that is equivalent to the particle size in the particle size distribution where the cumulative volume from the smaller particle size side is 90%.

5. The composite substrate according to claim 1, wherein, The fire extinguishing liquid capsule includes: Nuclear, including fire extinguishing liquids; and The shell, on the surface of the core, The shell comprises a polymer.

6. The composite substrate according to claim 5, wherein, The extinguishing liquid includes at least one of halogen compounds, solid aerosol extinguishing materials, potassium bicarbonate, sodium bicarbonate, manganese carbonate, and fluoroketone compounds.

7. The composite substrate according to claim 5, wherein, The polymer has a melting temperature in the range of 100°C to 260°C.

8. The composite substrate according to claim 1, wherein, The fire extinguishing liquid capsule has a structure of at least one of granular and flat shapes.

9. The composite substrate according to claim 1, wherein, The size of the fire extinguishing liquid capsule is in the range of 3μm to 10μm.

10. The composite substrate according to claim 1, wherein, The fire extinguishing liquid capsule has a long axis and a short axis. Wherein, the length of the major axis is in the range of 3μm to 10μm, and The length of the minor axis is in the range of 0.5 μm to 2 μm.

11. The composite substrate according to claim 5, wherein, The total thickness of the shell is 30% to 50% of the size of the fire extinguishing liquid capsule.

12. The composite substrate according to claim 1, wherein, The area of ​​the additive is between 1% and 10% relative to the unit cross-sectional area of ​​the support layer.

13. The composite substrate according to claim 1, wherein, The thickness of at least one of the first metal layer and the second metal layer is greater than 0 μm and equal to or less than 5 μm.

14. The composite substrate according to claim 1, wherein, The thickness of the support layer is in the range of 2 μm to 10 μm.

15. A rechargeable lithium battery, the rechargeable lithium battery comprising the composite substrate according to claim 1.

Images