Composite particles, method of preparation, positive and negative electrodes, and non-aqueous electrolyte rechargeable batteries

Abstract

Disclosed are composite particles for nonaqueous electrolyte rechargeable batteries, a method for producing the same, a positive electrode, a negative electrode, and a nonaqueous electrolyte rechargeable battery. The composite particles are composite particles including metal hydroxide particles and conductive particles, wherein a volume resistivity at about 60 MPa pressure is greater than or equal to about 0.10 Ωcm and less than or equal to about 4 x 10 4 Ωcm, an endothermic amount in differential scanning calorimetry between about 50°C and about 250°C is greater than or equal to about 150 J / g and less than or equal to about 500 J / g, and an amount (MS1) of P2 desorbed from about 80°C to about 1400°C by thermal desorption gas phase mass spectrometry (TDS-MS) is greater than or equal to about 300 x 10 ‑6 mol / g and less than or equal to about 3000 x 10 ‑6 mol / g.

Description

Technical Field

[0001] This disclosure relates to a composite particle for a non-aqueous electrolyte rechargeable battery, a method for manufacturing the composite particle, a positive electrode and a negative electrode, and a non-aqueous electrolyte rechargeable battery. Background Technology

[0002] Non-aqueous electrolyte rechargeable batteries, including rechargeable lithium-ion batteries, are widely used as power sources for smartphones, laptops, and more recently for large batteries (such as those used in vehicles).

[0003] On the other hand, rechargeable lithium-ion batteries have the advantage of high energy density, but because they use non-aqueous electrolytes, adequate safety measures are required. However, with the recent increase in battery size, ensuring safety has become even more important.

[0004] For example, when a rechargeable lithium-ion battery is placed in a high-temperature environment, there is a possibility that the positive electrode of the rechargeable lithium-ion battery will generate heat and the internal temperature of the battery will rise. When the internal temperature rises, a short circuit may occur due to the shrinkage of the separator included in the rechargeable lithium-ion battery. As a result, there is a possibility that the internal temperature may rise further.

[0005] Therefore, in order to ensure the safety of rechargeable lithium-ion batteries, it has been proposed to include inorganic particles composed of metal hydroxide particles with endothermic properties as endothermic particles in rechargeable lithium-ion batteries to suppress the rise in internal temperature.

[0006] For example, Patent Document 1 discloses including inorganic particles composed of endothermic alkaline calcium silicate, which have a specific surface area ratio greater than or equal to about 0.45 and less than or equal to about 2.0 by adsorbing water vapor and nitrogen, in a separator to improve battery safety.

[0007] In addition, Patent Documents 2 and 3 disclose that aluminum hydroxide particles having a maximum endothermic peak temperature greater than or equal to about 270°C and less than or equal to about 360°C and a dehydration reaction temperature range greater than or equal to about 200°C and less than or equal to about 400°C in differential scanning calorimetry (DSC) are included in an electrolyte or a diaphragm.

[0008] [Existing technical documents]

[0009] [Patent Literature]

[0010] (Patent Document 1) Japanese Patent No. 6925368

[0011] (Patent Document 2) Japanese Unexamined Patent Publication No. 2016-162528

[0012] (Patent Document 3) Japanese Patent No. 4364940 Summary of the Invention

[0013] However, according to the inventors' research, there are cases where the internal temperature of a non-aqueous electrolyte rechargeable battery cannot be adequately suppressed by the inorganic particles described in Patent Document 1.

[0014] Furthermore, within the temperature range described in Patent Documents 2 and 3, melting of the separator in the non-aqueous electrolyte rechargeable battery and decomposition of the charging positive electrode occur.

[0015] Furthermore, when the inorganic particles described in Patent Documents 1 to 3 are included in the positive or negative electrode of a non-aqueous electrolyte rechargeable battery, these inorganic particles have a high volume resistivity, which increases the overall resistance of the non-aqueous electrolyte rechargeable battery.

[0016] The present invention has been made in view of the above-mentioned problems and provides composite particles that can suppress the rise of the internal temperature of a non-aqueous electrolyte rechargeable battery even in environments where the internal temperature may rise due to battery abnormalities (such as internal short circuits) and can suppress the resistance of the non-aqueous electrolyte rechargeable battery to a low level.

[0017] In other words, the composite particles for non-aqueous electrolyte rechargeable batteries according to the present invention are composite particles comprising metal hydroxide particles and conductive particles, wherein the volume resistivity at a pressure of approximately 60 MPa is greater than or equal to approximately 0.10 Ωcm and less than or equal to approximately 4 × 10⁻⁶ Ωcm. 4 Ωcm, in differential scanning calorimetry, the heat endothermic between about 50 °C and about 250 °C is greater than or equal to about 150 J / g and less than or equal to about 500 J / g, and the amount of P2 desorbed by thermal desorption gas chromatography-mass spectrometry (TDS-MS) from about 80 °C to about 1400 °C (MS1) is greater than or equal to about 300 × 10⁻⁶ Ωcm. -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g.

[0018] According to the composite particles for non-aqueous electrolyte rechargeable batteries constructed as described above, since the degree of phosphonic acid modification, which is limited by the amount of P2 gas desorption, is set within an appropriate range, the rise in internal temperature of the non-aqueous electrolyte rechargeable battery including the composite particles can be sufficiently suppressed.

[0019] Furthermore, the volume resistivity of the composite particles is greater than or equal to approximately 0.10 Ωcm and less than or equal to approximately 4 × 10⁻⁶ when pressure is applied at approximately 60 MPa. 4Ωcm, therefore the resistance of non-aqueous electrolyte rechargeable batteries can be reduced to a low level even when these composite particles are included in the positive and / or negative electrodes.

[0020] For example, the amount of H2O desorbed from the composite particles from about 80°C to about 200°C (MS2), as determined by thermal desorption mass spectrometry (TDS-MS), can be greater than or equal to about 30 × 10⁻⁶. -6 mol / g and less than or equal to approximately 1500 × 10 -6 mol / g, and the desorbed gas ratio (MS1 / MS2) can satisfy equation (1).

[0021] 0.5≤(MS1 / MS2)≤5.0 (1)

[0022] 1350 cm⁻¹ measured by Raman spectroscopy of composite particles -1 Nearby peak area (A) D ) and 1580cm -1 Nearby peak area (A) G The ratio of (A) D / A G The value can be greater than or equal to about 0.5 and less than or equal to about 3.5, and is measured by Raman spectroscopy at 2680 cm⁻¹. -1 The full width at half maximum (FWHM) in the vicinity can be greater than or equal to approximately 60 cm. -1 And less than or equal to approximately 150cm -1 .

[0023] The specific surface area (BET1) of the composite particles, calculated based on the adsorption isotherm measured by adsorbing water vapor, can be greater than or equal to approximately 8 m². 2 / g and less than or equal to approximately 600m 2 / g, and the specific surface area (BET2) of the composite particles, calculated based on the adsorption isotherm measured by adsorbing nitrogen, can be greater than or equal to approximately 8m². 2 / g and less than or equal to approximately 600m 2 / g.

[0024] The specific surface area ratio (BET1 / BET2) can satisfy equation (2).

[0025] 0.2≤(BET1 / BET2)≤5.0 (2)

[0026] The amount of CH4 desorbed from the composite particles by thermal desorption gas chromatography-mass spectrometry (TDS-MS) from about 80 °C to about 1400 °C (MS3) can be greater than or equal to about 30 × 10⁻⁶. -6 mol / g and less than or equal to approximately 1000 × 10 -6The amount of CH3OH desorbed from the composite particles by TDS-MS from about 80 °C to about 1400 °C (MS4) can be greater than or equal to about 10 × 10 mol / g. -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g.

[0027] The amount of C6H6 desorbed by TDS-MS from about 80 °C to about 1400 °C (MS5) of the composite particles can be greater than or equal to about 1 × 10⁻⁶. -6 mol / g and less than or equal to approximately 4000 × 10 -6 mol / g.

[0028] In a specific embodiment, the metal hydroxide may be at least one selected from aluminum hydroxide, boehmite, boehmite, alumina and kaolinite.

[0029] It may also provide a positive or negative electrode for a non-aqueous electrolyte rechargeable battery and a non-aqueous electrolyte rechargeable battery having such positive or negative electrodes, wherein the positive or negative electrode for the non-aqueous electrolyte rechargeable battery comprises the above-described composite particles for the non-aqueous electrolyte rechargeable battery in an amount greater than or equal to about 0.1 wt% and less than or equal to about 5.0 wt% of the total weight of the positive electrode mixture layer of the positive electrode or the negative electrode mixture layer of the negative electrode, respectively.

[0030] The composite particles for non-aqueous electrolyte rechargeable batteries according to the present invention have an endothermic heat absorption of greater than or equal to about 150 J / g and less than or equal to about 500 J / g at about 50°C to about 250°C, and the degree of phosphonic acid modification is set within an appropriate range. As a result, even in environments where the internal temperature tends to rise due to battery anomalies (such as internal short circuits), the rise in internal temperature of the non-aqueous electrolyte rechargeable battery including the composite particles can be sufficiently suppressed.

[0031] As a result, it can suppress battery degradation caused by the increase in internal temperature of non-aqueous electrolyte rechargeable batteries and improve the cycle life of non-aqueous electrolyte rechargeable batteries.

[0032] Additionally, when the volume resistivity of the composite particles is greater than or equal to approximately 0.10 Ωcm and less than or equal to approximately 4 × 10⁻⁶ Ωcm... 4 When the Ωcm value is 0.05, the composite particles can be used as an endothermic conductive agent with both conductive and endothermic properties.

[0033] As a result, even when the composite particles according to the invention can be included in the positive or negative electrode, the resistance of the non-aqueous electrolyte rechargeable battery can be suppressed to a low level. Attached Figure Description

[0034] Figure 1This is a schematic diagram illustrating a non-aqueous electrolyte rechargeable battery according to an embodiment.

[0035] Figure 2 This is a schematic diagram illustrating the structure of the composite particles according to an embodiment. Detailed Implementation

[0036] The specific construction of the non-aqueous electrolyte rechargeable battery according to the embodiments will be described below.

[0037] <1. Basic Structure of Non-Aqueous Electrolyte Rechargeable Batteries>

[0038] The non-aqueous electrolyte rechargeable battery according to this embodiment is a rechargeable lithium-ion battery including a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte.

[0039] There are no particular restrictions on the shape of rechargeable lithium-ion batteries, and they can be, for example, cylindrical, prismatic, laminated, or button-shaped.

[0040] In the following text, reference will be made to Figure 1 A non-aqueous electrolyte rechargeable battery is described according to an embodiment. Figure 1 This is a schematic diagram illustrating a non-aqueous electrolyte rechargeable battery according to an embodiment. (Refer to...) Figure 1 According to an embodiment of the present invention, a rechargeable lithium battery 100 includes a battery cell, a battery casing 120 for housing the battery cell, and a sealing member 140 for sealing the battery casing 120. The battery cell includes a positive electrode 114, a negative electrode 112 facing the positive electrode 114, a separator 113 between the positive electrode 114 and the negative electrode 112, and an electrolyte (not shown) for impregnating the positive electrode 114, the negative electrode 112, and the separator 113 for the rechargeable lithium battery.

[0041] (1-1, Positive electrode)

[0042] The positive electrode includes a positive current collector and a layer of positive electrode mixture formed on the positive current collector. The positive current collector can be any material, as long as it is a conductor, and the positive current collector is, for example, plate-shaped or thin, and can be preferably made of aluminum, stainless steel, nickel-plated steel, etc.

[0043] The positive electrode mixture layer may include at least a positive electrode active material, and may also include a conductive agent and a positive electrode binder.

[0044] The positive electrode active material can be, for example, a transition metal oxide or solid solution oxide including lithium, and is not particularly limited, as long as it can electrochemically insert and extract lithium ions. Examples of transition metal oxides including lithium include Li. 1.0 Ni 0.88 Co 0.1 Al 0.01 Mg0.01 O2, etc. Additionally, examples of transition metal oxides including lithium may also include Li·Co composite oxides (such as LiCoO2), Li·Ni·Co·Mn-based composite oxides (such as LiNi), etc. x Co y Mn z Solid solution oxides include Li2O2, Li·Ni-based composite oxides (such as LiNiO2), or Li·Mn-based composite oxides (such as LiMn2O4). Examples of solid solution oxides may include Li2O2, LiNiO2, LiNiO2, or Li·MnO4. a Mn x Co y Ni z O2 (1.150≤a≤1.430, 0.45≤x≤0.6, 0.10≤y≤0.15, 0.20≤z≤0.28), LiMn 1.5 Ni 0.5 O4. On the other hand, there are no particular restrictions on the content (ratio) of the positive electrode active material, as long as it is suitable for the positive electrode mixture layer of a non-aqueous electrolyte rechargeable battery. Furthermore, these compounds can be used alone or in various types of mixtures.

[0045] There are no particular limitations on the conductive agent, as long as it is used to increase the conductivity of the positive electrode. Specific examples of conductive agents may include those comprising at least one selected from carbon black, natural graphite, artificial graphite, fibrous carbon, and flake carbon.

[0046] Examples of carbon black may include furnace black, channel black, thermal crack black, Ketjen black, and acetylene black.

[0047] Examples of fibrous carbon can include carbon nanotubes and carbon nanofibers, while examples of sheet-like carbon include graphene, etc.

[0048] There is no particular limitation on the content of conductive agent in the positive electrode mixture layer. However, from the viewpoint of achieving both conductivity and battery capacity, based on the total amount of the positive electrode mixture layer, the content of conductive agent in the positive electrode mixture layer can be greater than or equal to about 0.1 wt% and less than or equal to about 5 wt%, or greater than or equal to about 0.5 wt% and less than or equal to about 3 wt%.

[0049] Positive electrode binders can include, for example, fluorinated resins (such as polyvinylidene fluoride), ethylene-containing resins (such as styrene-butadiene rubber), ethylene-propylene diene terpolymers, acrylonitrile-butadiene rubber, fluororubber, polyvinyl acetate, polymethyl methacrylate, polyethylene, polyvinyl alcohol, carboxymethyl cellulose, carboxymethyl cellulose derivatives (salts of carboxymethyl cellulose, etc.), nitrocellulose, etc. The positive electrode binder can be any material capable of bonding the positive electrode active material and conductive agent to the positive electrode current collector, and there are no particular limitations.

[0050] (1-2. Negative Electrode)

[0051] The negative electrode comprises a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector.

[0052] The negative electrode current collector may be any substance as long as it is a conductor, and the negative electrode current collector may desirably be plate-shaped or thin, and is made of copper, stainless steel, nickel-plated steel, or the like.

[0053] The negative electrode mixture layer may comprise at least a negative electrode active material, and may further comprise a conductive agent and a negative electrode binder.

[0054] The negative electrode active material is not particularly limited as long as it can electrochemically intercalate and deintercalate lithium ions, but the negative electrode active material may be, for example, a graphite active material (artificial graphite, natural graphite, a mixture of artificial graphite and natural graphite, natural graphite coated with artificial graphite), a Si-based active material or a Sn-based active material (for example, fine particles of silicon (Si) or tin (Sn) or a mixture of an oxide thereof and a graphite active material, particles of silicon or tin, an alloy comprising silicon or tin as a base material), metallic lithium, a titanium oxide compound such as Li4Ti5O 12 ), lithium nitride, or the like. As the negative electrode active material, one of the above examples may be used, or two or more thereof may be used in combination. On the other hand, the oxide of silicon may be represented by SiO x (0<x≤2).

[0055] The conductive agent is not particularly limited as long as it is used to enhance the conductivity of the negative electrode, and for example, the same conductive agent as described in the positive electrode section may be used.

[0056] The content of the conductive agent in the negative electrode mixture layer is not particularly limited, but from the perspective of achieving both conductivity and battery capacity, based on the total weight of the negative electrode mixture layer, the content of the conductive agent in the negative electrode mixture layer may be greater than or equal to about 0.1 wt% and less than or equal to about 5 wt%, or greater than or equal to about 0.5 wt% and less than or equal to about 3 wt%.

[0057] The negative electrode binder may be any binder capable of binding the negative electrode active material and the conductive agent onto the negative electrode current collector, and is not particularly limited. The negative electrode binder may be, for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene copolymer (SBR), metal salts of carboxymethyl cellulose (CMC), or the like. The binder may be used alone or as a mixture of two or more types.

[0058] (1-3. Separator)

[0059] There are no particular restrictions on the separator, and any separator can be used as long as it is used as a separator for a rechargeable lithium-ion battery. The separator can be a porous membrane, nonwoven fabric, etc., exhibiting excellent high-rate discharge performance alone or in combination. The resin constituting the separator can be, for example, polyolefin resins (such as polyethylene, polypropylene, etc.), polyester resins (such as polyethylene terephthalate, polybutylene terephthalate, etc.), polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-hexafluoroacetone copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-propylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-ethylene-tetrafluoroethylene copolymer, etc. On the other hand, there are no particular restrictions on the porosity of the separator, and the porosity of the separator of a conventional rechargeable lithium-ion battery can be used arbitrarily.

[0060] The separator may also include a surface layer covering the surface of the aforementioned porous membrane or nonwoven fabric. The surface layer may include an adhesive for securing the battery element by adhering it to the electrodes. Examples of adhesives may include vinylidene fluoride-hexafluoropropylene copolymers, acid-modified products of vinylidene fluoride polymers, and styrene-(meth)acrylate copolymers.

[0061] (1-4, Non-aqueous electrolytes)

[0062] As a non-aqueous electrolyte, the same non-aqueous electrolytes already commonly used in rechargeable lithium-ion batteries can be used without particular limitation. The non-aqueous electrolyte has a composition in which the electrolyte salt is contained in a non-aqueous solvent, which is a solvent used for the electrolyte. Examples of non-aqueous solvents may include cyclic carbonates (such as propylene carbonate, ethylene carbonate, butene carbonate, chloroethylene carbonate, fluoroethylene carbonate, and vinylene carbonate), cyclic esters (such as γ-butyrolactone and γ-valerolactone), chain carbonates (such as dimethyl carbonate, diethyl carbonate, or methyl ethyl carbonate), chain esters (such as methyl formate, methyl acetate, methyl butyrate, ethyl propionate, and propyl propionate), ethers (such as tetrahydrofuran or derivatives thereof, 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxyethane, 1,4-dibutoxyethane, methyl diethylene glycol dimethyl ether, ethylene glycol monopropyl ether, or propylene glycol monopropyl ether), nitriles (such as acetonitrile and benzyl nitrile), dioxolane or derivatives thereof, ethyl sulfide, sulfolane, sulfonyl lactone or derivatives thereof. On the other hand, when two or more types of non-aqueous solvents are mixed and used, the mixing ratio of each non-aqueous solvent can be a mixing ratio that can be used in conventional rechargeable lithium-ion batteries.

[0063] Examples of the electrolyte salt may include inorganic ionic salts containing one of lithium (Li), sodium (Na) and potassium (K), such as LiClO4, LiBF4, LiAsF6, LiPF6, LiPF 6-x (C n F 2n+1 ) x , with the condition that 1<x<6, n=1 or 2, LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10 , NaClO4, NaI, NaSCN, NaBr, KClO4 or KSCN), or organic ionic salts (such as LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiN(CF3SO2)(C4F9SO2), LiC(CF3SO2)3, LiC(C2F5SO2)3, (CH3)4NBF4, (CH3)4NBr, (C2H5)4NClO4, (C2H5)4NI, (C3H7)4NBr, (n-C4H9)4NClO4, (n-C4H9)4NI, (C2H5)4N-maleate, (C2H5)4N-benzoate, (C2H5)4N-phthalate, lithium stearyl sulfonate, lithium octyl sulfonate, lithium dodecylbenzene sulfonate, etc.), and these ionic compounds can also be used alone or as a mixture of two or more types. Meanwhile, the concentration of the electrolyte salt may be the same as that of the non-aqueous electrolyte used in conventional rechargeable lithium-ion batteries, and is not particularly limited. In embodiments, it is desirable to use a non-aqueous electrolyte containing the above lithium compound (electrolyte salt) at a concentration of greater than or equal to about 0.8 mol / L and less than or equal to about 1.5 mol / L.

[0064] Meanwhile, various additives can be added to the non-aqueous electrolyte. Examples of such additives may include negative electrode effect additives, positive electrode effect additives, ester additives, carbonate additives, sulfate ester additives, phosphate ester additives, borate ester additives, acid anhydride additives and electrolyte additives. One of these additives can be added to the non-aqueous electrolyte, and multiple types of additives can be added.

[0065] <2. Characteristic Configuration of Non-Aqueous Electrolyte Rechargeable Battery According to Embodiment>

[0066] Hereinafter, the characteristic configuration of the non-aqueous electrolyte rechargeable battery according to the embodiment will be described.

[0067] In addition to the above components, the positive electrode mixture layer of the non-aqueous electrolyte rechargeable battery according to the present embodiment may further include composite particles that serve as a heat-absorbing conductive agent for the non-aqueous electrolyte rechargeable battery.

[0068] These composite particles are composite particles that can be combined through an endothermic reaction of endothermic metal hydroxide particles and conductive particles. For example... Figure 2 As shown, composite particles can be obtained by mixing metal hydroxide particles and conductive particles as uniformly as possible. Here, composite refers to the state in which multiple particles are chemically bonded to each other as a single aggregate through the functional groups (e.g., carboxyl and hydroxyl groups) possessed by each particle. The chemical bonds here can include not only covalent bonds as described above, but also various bonds such as ionic bonds, coordination bonds, and metallic bonds. On the other hand, the bonding state between particles can be confirmed by, for example, X-ray photoelectron spectroscopy.

[0069] There are no particular limitations on the metal hydroxide particles, as long as they can induce an endothermic reaction. Specific examples of metal hydroxides can include aluminum hydroxide, pseudo-boehmite, boehmite, alumina, and kaolinite. These can be used alone or in combination of two or more types.

[0070] The average primary particle size of the metal hydroxide particles can be greater than or equal to about 10 nm and less than or equal to about 20 μm, or greater than or equal to about 50 nm and less than or equal to about 10 μm.

[0071] Conductive particles can be conductive and are not particularly limited in their properties. Specific examples of materials that include conductive particles can include carbon materials, metal nanoparticles, etc.

[0072] Examples of metal nanoparticles may include gold nanoparticles, silver nanoparticles, and copper nanoparticles.

[0073] Examples of carbon materials may include at least one selected from carbon black, natural graphite, artificial graphite, fibrous carbon, and flake carbon.

[0074] Examples of carbon black may include furnace black, channel black, thermal crack black, Ketjen black, and acetylene black.

[0075] Examples of fibrous carbon can include single-walled carbon nanotubes and multilayer carbon nanotubes, while examples of sheet-like carbon include graphene, etc.

[0076] The composite particles contain the aforementioned conductive particles, and the composite particles exhibit a 1350 cm⁻¹ conductivity measured by Raman spectroscopy. -1 Peak area (A) in the vicinity (left and right) D ) and 1580cm -1 Nearby peak area (A) G The ratio of (A) D / A GThe value can be greater than or equal to about 0.5 and less than or equal to about 3.5, for example, greater than or equal to about 1.1 and less than or equal to about 1.3, and is measured by Raman spectroscopy at 2680 cm⁻¹. -1 The full width at half maximum (FWHM) in the vicinity can be greater than or equal to approximately 60 cm. -1 And less than or equal to approximately 150cm -1 For example, greater than or equal to approximately 80cm -1 And less than or equal to approximately 85cm -1 .

[0077] The average primary particle size or fiber length of the conductive particles can be greater than or equal to about 1 nm and less than or equal to about 10 μm, or greater than or equal to about 10 nm and less than or equal to about 1 μm. When using metal nanoparticles as conductive particles, any particle size can be used, as long as the average primary particle size is in the nanometer range, and, for example, the average primary particle size can be greater than or equal to about 1 nm and less than or equal to about 500 nm.

[0078] Based on the total weight of the composite particles, the content of hydroxide particles in the composite particles can be in the range of greater than or equal to about 1 wt% and less than or equal to about 60 wt%, greater than or equal to about 5 wt% and less than or equal to about 50 wt%, or greater than or equal to about 10 wt% and less than or equal to about 40 wt%.

[0079] Based on the total weight of the composite particles, the content of conductive particles in the composite particles can be in the range of greater than or equal to about 0.1 wt% and less than or equal to about 25 wt%, greater than or equal to about 0.5 wt% and less than or equal to about 20 wt%, or greater than or equal to about 1 wt% and less than or equal to about 15 wt%.

[0080] Composite particles can have specific surface areas within the following ranges and degrees of modification by various modifiers.

[0081] The specific surface area (BET1) calculated based on the adsorption isotherm measured by adsorbing water vapor onto the composite particles can be greater than or equal to approximately 8 m². 2 / g and less than or equal to approximately 600m 2 / g, and simultaneously, based on the adsorption isotherm measured by adsorbing nitrogen onto the composite particles, the specific surface area (BET2) can be greater than or equal to approximately 8m². 2 / g and less than or equal to approximately 600m 2 / g, for example, can be greater than or equal to about 10m 2 / g and less than or equal to approximately 600m 2 / g.

[0082] BET1 can be greater than or equal to approximately 10m2 / g and less than or equal to approximately 300m 2 / g, or greater than or equal to approximately 12m 2 / g and less than or equal to approximately 100m 2 / g.

[0083] BET2 can be greater than or equal to approximately 9m 2 / g and less than or equal to approximately 300m 2 / g, or greater than or equal to approximately 10m 2 / g and less than or equal to approximately 100m 2 / g.

[0084] The specific surface area ratio (BET1 / BET2) between BET1 and BET2 can be greater than or equal to about 0.2 and less than or equal to about 5.0, greater than or equal to about 0.5 and less than or equal to about 4.0, or greater than or equal to about 1.0 and less than or equal to about 3.0.

[0085] Furthermore, when the composite particles are heated from approximately 80°C to approximately 1400°C, the amount of P2 gas desorbed from the composite particles can be measured by TDS-MS, and the amount of desorbed P2 (referred to as MS1) can be greater than or equal to approximately 300 × 10⁻⁶. -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g, for example, greater than or equal to about 500 × 10⁻⁶ mol / g -6 mol / g and less than or equal to approximately 1000 × 10 -6 mol / g. On the other hand, the amount of desorbed P2 gas (MS1) is an index indicating the degree of modification of the composite particles with phosphonic acid.

[0086] When the composite particles are heated from about 80°C to about 1400°C, the amount of H2O desorbed from the composite particles (referred to as MS2), as measured by TDS-MS, can be greater than or equal to about 30 × 10⁻⁶. -6 mol / g and less than or equal to approximately 1500 × 10 -6 mol / g, for example, can be greater than or equal to about 100 × 10⁻⁶ mol / g -6 mol / g and less than or equal to approximately 1500 × 10 -6 mol / g. The amount of desorbed H2O can be a reference value for the degree of modification of the composite particles, and the ratio of desorbed amounts (MS1 / MS2) can be greater than or equal to about 0.5 and less than or equal to about 5.0, greater than or equal to about 1.0 and less than or equal to about 4.0, or greater than or equal to about 1.5 and less than or equal to about 3.0.

[0087] To further enhance the endothermic effect of the composite particles, the composite particles can be modified with functional groups (such as CH3 or CH2OH groups). The degree of modification of these functional groups can be evaluated in the same manner as that of phosphonic acid modification by the desorption of various gases derived from these functional groups, and the desorption of various gases meets the following ranges.

[0088] When the composite particles are heated from about 80°C to about 1400°C, the amount of CH4 desorbed from the composite particles, as measured by TDS-MS (referred to as MS3), can be greater than or equal to about 30 × 10⁻⁶. -6 mol / g and less than or equal to approximately 1000 × 10 -6 The amount of desorbed CH3OH, measured in the same manner (referred to as MS4), can be greater than or equal to approximately 10 × 10 mol / g. -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g, for example, can be greater than or equal to about 10 × 10 -6 mol / g and less than or equal to approximately 1000 × 10 -6 mol / g.

[0089] MS3 can be greater than or equal to approximately 50 × 10 -6 mol / g and less than or equal to approximately 300 × 10 -6 mol / g, or greater than or equal to approximately 60 × 10⁻⁶ -6 mol / g and less than or equal to approximately 250 × 10 -6 mol / g.

[0090] MS4 can be greater than or equal to approximately 20 × 10 -6 mol / g and less than or equal to approximately 2000 × 10⁻⁶ -6 mol / g, or greater than or equal to approximately 25 × 10⁻⁶ -6 mol / g and less than or equal to approximately 1900 × 10 -6 mol / g.

[0091] Furthermore, when using composite particles modified with phenyl functional groups, it is easy to disperse the composite particles in the solvent during the preparation of slurries (such as cathode mixture slurries).

[0092] Therefore, the amount of C6H6 desorbed from about 80 °C to about 1400 °C by TDS-MS (referred to as MS5) of the composite particles can be greater than or equal to about 1 × 10⁻⁶. -6 mol / g and less than or equal to approximately 4000 × 10 -6 mol / g, greater than or equal to approximately 2 × 10 -6 mol / g and less than or equal to approximately 2000 × 10⁻⁶ -6mol / g, or greater than or equal to approximately 3 × 10 -6 mol / g and less than or equal to approximately 1600 × 10 -6 mol / g.

[0093] Based on 100 wt% of total composite particles, the total content of modified molecules in the composite particles can be in the range of greater than or equal to about 10 wt% and less than or equal to about 90 wt%, greater than or equal to about 20 wt% and less than or equal to about 80 wt%, or greater than or equal to about 30 wt% and less than or equal to about 70 wt%.

[0094] Regarding the endothermic properties of composite particles achieved by surface area and the degree of modification by the various modifiers described above, the endothermic heat in differential scanning calorimetry between about 50°C and about 250°C can be greater than or equal to about 150 J / g and less than or equal to about 500 J / g, greater than or equal to about 170 J / g and less than or equal to about 400 J / g, or greater than or equal to about 180 J / g and less than or equal to about 300 J / g.

[0095] Even when the composite particles are included in the positive or negative electrode mixture layer, in order to minimize the reduction in conductivity, the volume resistivity of the composite particles can be greater than or equal to about 0.1 Ωcm and less than or equal to about 4 × 10⁻⁶ when a pressure of about 60 MPa is applied. 4 Ωcm. The volume resistivity can be greater than or equal to about 0.3 Ωcm and less than or equal to about 3.8 × 10⁻⁶ Ωcm. 4 Ωcm, or greater than or equal to about 0.5 Ωcm and less than or equal to about 3.6 × 10⁻⁶ Ωcm. 4 Ωcm.

[0096] Based on the total weight of the cathode mixture layer, the content of composite particles in the cathode mixture layer can be in the range of greater than or equal to about 0.1 wt% and less than or equal to about 5 wt%, greater than or equal to about 0.2 wt% and less than or equal to about 3 wt%, or greater than or equal to about 0.5 wt% and less than or equal to about 2 wt%.

[0097] The content of composite particles for use in non-aqueous electrolyte rechargeable batteries can vary depending on the intended use of the batteries, and is therefore not limited to the following ranges. However, for example, based on 100 wt% of the total weight of the non-aqueous electrolyte rechargeable battery, the content of composite particles for use in the non-aqueous electrolyte rechargeable battery may be in the range of greater than or equal to about 0.01 wt% and less than or equal to about 5.0 wt%, greater than or equal to about 0.02 wt% and less than or equal to about 2.0 wt%, or greater than or equal to about 0.1 wt% and less than or equal to about 0.5 wt%.

[0098] <3. Method for manufacturing a non-aqueous electrolyte rechargeable battery according to the embodiment>

[0099] The following describes a method for manufacturing a rechargeable lithium-ion battery according to this embodiment.

[0100] (3-1. Preparation method of composite particles)

[0101] The composite particles for non-aqueous electrolyte rechargeable batteries according to this embodiment can be prepared by preparing a first composite particle of metal hydroxide particles and conductive particles and modifying the first composite particle.

[0102] The first composite particles are obtained by the following steps: First, metal nitrides and conductive particles, which are used as raw materials for metal hydroxides, are mixed, dried and heated to prepare metal hydroxide particles, thereby forming the first composite particles of metal hydroxide particles and conductive particles.

[0103] The heating temperature can be greater than or equal to about 80°C and less than or equal to about 200°C, or greater than or equal to about 120°C and less than or equal to about 180°C.

[0104] The method of thermally mixing the metal hydroxide raw material and the conductive particles can be a spray dryer. Since the first composite particles are obtained by using the spray dryer in a state where the metal hydroxide particles and conductive particles are combined as uniformly as possible, the spray dryer can be expected to be used to prepare the first composite particles.

[0105] The method for modifying the first composite particles may be, for example, immersing the first composite particles in a modifier for a predetermined time period.

[0106] Examples of modifiers may include phosphoric acid, phosphonic acid (such as phosphonic acid, ethylphosphonic acid and phenylphosphonic acid) and hypophosphonic acid (such as hypophosphonic acid and diphenylphosphonic acid).

[0107] The treatment time for modifying the first composite particles can be appropriately varied depending on the type or concentration of the treatment agent, and can be greater than or equal to about 30 minutes and less than or equal to about 48 hours, or greater than or equal to about 1 hour and less than or equal to about 30 hours.

[0108] The treatment temperature can also be appropriately selected according to the type and concentration of the treatment agent, but the treatment temperature can be greater than or equal to about 30°C and less than or equal to about 90°C, or greater than or equal to about 40°C and less than or equal to about 80°C.

[0109] (3-2, Manufacturing method of positive electrode)

[0110] The positive electrode is prepared as follows. First, a positive electrode slurry is formed by dispersing a mixture of positive electrode active material, conductive agent, positive electrode binder, and composite particles in a desired proportion in a solvent used for the positive electrode slurry. Next, the positive electrode slurry is coated onto a positive electrode current collector and dried to form a positive electrode mixture layer. The coating method is not particularly limited. Coating methods may include blade coating, gravure coating, reverse roll coating, slit coating, etc. Each of the following coating processes is performed using the same method. Subsequently, the positive electrode material mixture layer is pressed using a press to achieve a desired density. Thus, the positive electrode is manufactured.

[0111] (3-3, Manufacturing method of negative electrode)

[0112] The negative electrode is prepared in the same manner as the positive electrode. First, a negative electrode slurry is prepared by dispersing a mixture of materials constituting the negative electrode mixture layer in a solvent used for the negative electrode slurry. Next, the negative electrode mixture layer is formed by coating the negative electrode slurry onto a negative electrode current collector and allowing it to dry. Then, the negative electrode material mixture layer is pressed using a press to achieve the desired density. Thus, the negative electrode is manufactured.

[0113] (3-4. Manufacturing method of non-aqueous electrolyte rechargeable battery)

[0114] Next, an electrode structure is fabricated by placing a separator between the positive and negative electrodes. The electrode structure can then be shaped into a desired form (e.g., cylindrical, prismatic, laminated, button-shaped, etc.) and inserted into a container of that shape. Subsequently, a non-aqueous electrolyte is inserted into the corresponding container to impregnate each pore in the separator or the gap between the positive and negative electrodes. This process produces a rechargeable lithium-ion battery.

[0115] <4. Effects of this embodiment>

[0116] According to the non-aqueous electrolyte rechargeable battery constructed as described above, even in environments where the internal temperature may rise due to battery abnormalities (such as internal short circuits), the rise in the internal temperature of the non-aqueous electrolyte rechargeable battery can be sufficiently suppressed, and the resistance of the non-aqueous electrolyte rechargeable battery can be suppressed to a low level.

[0117] <5. Another embodiment>

[0118] The present invention is not limited to the foregoing embodiments.

[0119] In the foregoing embodiments, the case where the positive electrode includes composite particles according to the invention has been described; however, the negative electrode may also include composite particles. When the negative electrode includes composite particles, it may include the same amount of composite particles as when the positive electrode includes composite particles.

[0120] Furthermore, the composite particles may be included in the electrolyte, or may be included in multiple locations in the positive electrode, negative electrode, and electrolyte.

[0121] When the negative electrode includes composite particles for a non-aqueous electrolyte rechargeable battery, the content of these composite particles relative to the total negative electrode can be within the same range as the content of the composite particles for a non-aqueous electrolyte rechargeable battery in the positive electrode. When the electrolyte includes composite particles for a non-aqueous electrolyte rechargeable battery, when the total weight of the electrolyte is 100 wt%, the content of these composite particles is in the range of greater than or equal to about 0.1 wt% and less than or equal to about 10.0 wt%.

[0122] Furthermore, the present invention is not limited to these embodiments, but can be modified in various ways without departing from the purpose.

[0123] [Example]

[0124] The invention will be described in more detail below with reference to specific examples. However, the following examples are merely one example of the invention, and the invention is not limited to these examples.

[0125] [Preparation of endothermic particles]

[0126] <Preparation of Endothermic Particles>

[0127] (Examples 1 through 4 and comparison example 4)

[0128] 50.0 g of aluminum nitrate nonahydrate and 5.0 g of acetylene black were dispersed in 250 cc of ethanol. The dispersion was spray-dried at 150 °C using a spray dryer manufactured by GF Corp. to obtain composite particles A′ (BET1: 344m) of unmodified aluminum hydroxide particles and acetylene black particles bonded together. 2 / g, BET2: 1.2m 2 / g).

[0129] (Examples 5 and 7)

[0130] 50.0 g of aluminum nitrate nonahydrate and 25.0 g of acetylene black were dispersed in 250 cc of ethanol. The dispersion was spray-dried at 150 °C using a spray dryer manufactured by GF Corp. to obtain composite particles B′ (BET1: 344m) of unmodified aluminum hydroxide particles and acetylene black particles bonded together. 2 / g, BET2: 1.2m 2 / g).

[0131] (Example 6)

[0132] 50.0 g of aluminum nitrate heptahydrate and 1.0 g of acetylene black were dispersed in 250 cc of ethanol. The dispersion was spray-dried at 150 °C using a spray dryer manufactured by GF Corp. to obtain composite particles C′(BET1: 344m) of unmodified aluminum hydroxide particles and acetylene black particles bonded together. 2 / g, BET2: 1.2m 2 / g).

[0133] <Modification Treatment of Heat-Endothermic Particles>

[0134] (Example 1)

[0135] 1.0 g of unmodified composite particles A′ and 3.0 g of phosphoric acid were dispersed in a mixed solution of 50 cc of purified water and ethanol (volume ratio 1:1). The dispersion was heated at 80 °C for 4 hours and then vacuum dried to obtain modified composite particles A.

[0136] (Example 2)

[0137] Modified composite particles B were obtained in the same manner as in Example 1, except that 1.0 g of unmodified composite particles A′ and 3.0 g of ethylphosphonic acid were dispersed in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1).

[0138] (Example 3)

[0139] Modified composite particles C were obtained in the same manner as in Example 1, except that 1.0 g of unmodified composite particles A′ and 3.0 g of phenylphosphonic acid were dispersed in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1).

[0140] (Example 4)

[0141] Modified composite particles D were obtained in the same manner as in Example 1, except that 1.0 g of unmodified composite particles A′ and 3.0 g of diphenylphosphine were dispersed in a mixed solution of 50 cc ethanol and pure (volume mixing ratio of 1:1).

[0142] (Example 5)

[0143] Modified composite particles E were obtained in the same manner as in Example 1, except that 1.0 g of unmodified composite particles B′ and 3.0 g of phenylphosphonic acid were dispersed in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1).

[0144] (Example 6)

[0145] Except that 1.0 g of unmodified composite particles C′ and 5.0 g of phenylphosphonic acid were dispersed in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1), the modified composite particles F were obtained in the same manner as in Example 1.

[0146] (Compare with Example 6)

[0147] In addition to 1.0g of pseudoboehmite (BET1:407m) 2 / g, BET2: 377m 2 Modified boehmite particles were obtained in the same manner as in Example 1, except that 3.0 g of phenylphosphonic acid was dispersed in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1).

[0148] <Preparation of a mixture of heat-absorbing and conductive particles>

[0149] (Compare with Example 7)

[0150] 10.0 g of the modified pseudoboehmite particles from Comparative Example 6 and 10.0 g of acetylene black were mixed for 10 minutes using a V-type mixer manufactured by Dalton Corp. to obtain particle mixture a.

[0151] (Compare with Example 8)

[0152] 20.0 g of the modified pseudoboehmite particles from Comparative Example 6 and 10.0 g of acetylene black were mixed for 10 minutes using a V-type mixer manufactured by Dalton Corp. to obtain particle mixture b.

[0153] (Compare with Example 9)

[0154] 10.0 g of the modified pseudoboehmite particles from Comparative Example 6 and 30.0 g of acetylene black were mixed for 10 minutes using a V-type mixer manufactured by Dalton Corp. to obtain particle mixture c.

[0155] (Compare with Example 10)

[0156] 10.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 10.0 g of acetylene black and 10.0 g of acetylene black were mixed for 10 minutes using a V-type mixer manufactured by Dalton Corp. to obtain particulate mixture d.

[0157] [The manufacture of the positive electrode]

[0158] (Examples 1 through 6 and Comparative Examples 2 through 10)

[0159] LiCoO2, acetylene black, polyvinylidene fluoride, and endothermic particles, as dry powders, were mixed and dispersed in N-methyl-2-pyrrolidone solvent at a weight ratio of 97.0:1.0:1.3:0.7 to prepare a positive electrode mixture slurry. The slurry was then coated onto one surface of an aluminum current collector foil to ensure that each surface had a surface temperature of 20.0 mg / cm² after drying. 2 The mixture is coated with a certain amount of material (surface density), then dried, and then pressed with a roller press to produce each positive electrode with a mixture layer density of 4.15 g / cc.

[0160] (Compare Example 1 and Example 7)

[0161] Each cathode was manufactured in the same manner as in Example 1, except that a cathode mixture slurry was prepared by mixing LiCoO2, acetylene black and polyvinylidene fluoride as dry powders in a weight ratio of 97.7:1.0:1.3 and dispersing them in an N-methyl-2-pyrrolidone solvent.

[0162] [Manufacturing the negative electrode]

[0163] (Examples 1 through 6 and Comparative Examples 1 through 10)

[0164] A negative electrode mixture slurry was prepared by dissolving and dispersing artificial graphite, sodium carboxymethyl cellulose (CMC), and styrene-butadiene-based aqueous dispersions as dry powders in an aqueous solvent at a weight ratio of 97.5:1.0:1.5. Subsequently, the negative electrode mixture slurry was coated onto one surface of a copper foil and dried to achieve a surface finish of 10.5 mg / cm² after drying. 2 The mixture is coated with a certain amount of material (surface density), then dried, and then pressed with a roller press to produce a mixture layer density of 1.65 g / cc, thereby manufacturing the negative electrode.

[0165] (Example 7)

[0166] The negative electrode was manufactured in the same manner as in Example 1, except that the negative electrode mixture slurry was prepared by dissolving and dispersing artificial graphite, sodium carboxymethyl cellulose (CMC), styrene-butadiene aqueous dispersion, and composite particles E of Example 5 in an aqueous solvent at a weight ratio of 96.5:1.0:1.5:1.0.

[0167] [Manufacturing of rechargeable battery cells]

[0168] (Examples 1 through 7 and Comparative Examples 1 through 10)

[0169] An electrode stack is fabricated by stacking multiple positive and multiple negative electrodes with a porous polypropylene separator between the positive and negative electrodes to achieve a battery design capacity of 300 mAh. A rechargeable battery is then manufactured prior to initial charging via the following steps: nickel and aluminum leads are soldered to the negative and positive electrodes of the electrode stack, respectively; the electrode stack is housed in an aluminum laminate with the leads pulled out from the outside; an electrolyte is injected therein; and the aluminum laminate is sealed under reduced pressure. The electrolyte is prepared by dissolving 1.3 M LiPF6 and 1 wt% vinylene carbonate in a mixed solvent of ethylene carbonate / dimethyl carbonate / fluoroethylene carbonate in a volume ratio of 15 / 80 / 5.

[0170] [Evaluation of heat-absorbing particles]

[0171] The endothermic particles used in the evaluation and comparison examples are as follows.

[0172] <Specific surface area (BET) of endothermic particles>

[0173] The specific surface area of ​​inorganic or composite particles was measured using a gas adsorption capacity measuring device (BELSORP manufactured by Microtrac Bell) according to JIS K6217-2 (based on BET (BET1 or BET2) calculated from the adsorption isotherm measured by adsorption of water vapor or nitrogen).

[0174] <Mass of desorbed gas>

[0175] Thermal desorption gas mass spectrometry (TDS-MS) was performed using a thermal desorption gas mass spectrometer (TDS-1200, ESCO, Ltd.) to measure and analyze the desorption amounts of methane, methanol, benzene, diphosphorus, and water molecules as follows.

[0176] In TDS, the negative electrode active material was set using a sample stage made of quartz and a sample disk made of SiC. The heating rate was 60 °C / min. Temperature rise was controlled by monitoring the temperature on the sample surface. Furthermore, the sample weight, corrected for actual weight, was 1 mg. Detection was performed using a quadrupole mass spectrometer with an applied voltage of 1000 V.

[0177] TDS is used to measure the amount (μmol / g) of each gas desorbed from inorganic or composite particles during a temperature increase from 80°C to 1400°C. The mass number [M / z] used to analyze the measurement results is 15 for CH4, 18 for H2O, 31 for CH3OH, 62 for P2, and 78 for C6H6, where the mass number corresponds to each of the aforementioned substances. Here, regarding the amount of H2O, only the integral value over the entire temperature range from 80°C to 200°C is used to obtain the amount of desorbed H2O (MS2).

[0178] Maximum heat absorption peak temperature

[0179] The maximum endothermic peak temperature of the endothermic particles was measured by using a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Co., Ltd.) according to JIS K7121, increasing the temperature at a heating rate of 5 K / min, and confirming the peak of the endothermic decomposition temperature.

[0180] <Confirmed heat generation at 150°C or lower with the coexistence of endothermic particles and electrolytes>

[0181] After placing 2.0 mg of endothermic particles and 0.5 mg of the same electrolyte used to manufacture rechargeable battery cells into a dedicated airtight container and sealing it, the presence of an exothermic peak at 150°C or lower was checked by examining the endothermic peak using the same method described above. As a result, a significant exothermic peak was observed near 100°C in Comparative Examples 6 to 9, but this exothermic peak was not observed in Examples 1 to 7.

[0182] <Bulk density and volume resistivity of powder under 60 MPa pressure>

[0183] When endothermic particles filled in a cylindrical body are formed into a powder that is pressed by a hydraulic press, the bulk density and volume resistivity of the pressurized powder are measured using an MCP-PD51 (Nitto Seiko Analytech Ltd.). The measurement conditions are as follows.

[0184] Load: 18.85kN

[0185] Electrode gap: 3.0mm

[0186] Electrode radius: 0.7mm

[0187] Sample radius: 10.0 mm

[0188] Probes used: 4 probes

[0189] Raman Spectroscopy Analysis

[0190] Each endothermic particle was measured using an NRS-5100 (Nippon Spectroscopy Ltd.) as a micro-laser Raman spectrometer at an excitation wavelength of 532.36 nm. The measurement conditions are as follows.

[0191] Exposure time: 10 seconds

[0192] Cumulative times: 20 times

[0193] Diffraction lattice: 300 / mm (600nm)

[0194] In the Raman spectrum of the entire measurement area, for 800 cm⁻¹ -1 Up to 3500cm -1 Perform curve fitting on the spectrum to obtain 1350 cm⁻¹ -1 Nearby peak area (A) D ) and 1580cm -1 Nearby peak area (A) G The ratio of (A) D / A G ) and 2680cm -1 The full width at half peak (G'-FWHM) in the vicinity.

[0195] [Evaluation of Rechargeable Battery Cells]

[0196] <Individual Battery Resistance>

[0197] The initial resistance of a fully charged cell was measured by electrochemical impedance spectroscopy (EIS, VMP-3 Potentiostat) at 25 °C. Measurement conditions included a frequency range of 100 kHz to 100 mHz and an applied voltage of 10 mV. The diameter of the semicircular arc of the Nyquist plot obtained from the measurements was taken as the cell resistance.

[0198] <Cyclic Characteristics>

[0199] In a 25°C thermostat, rechargeable battery cells according to Examples 1 to 7 and Comparative Examples 1 to 10 were charged to 4.3V at a design capacity of 0.1CA under constant current, and then charged to 0.05CA at 4.3V under constant voltage. Subsequently, the battery cells were discharged to 3.0V at 0.1CA under constant current. Furthermore, in the 25°C thermostat, after the first cycle of constant current charging at 0.2CA, constant voltage charging at 0.05CA, and constant current discharging at 0.2CA under conditions of a charging cutoff voltage of 4.3V and a discharging cutoff voltage of 3.0V, the initial discharge capacity of the battery cells was measured. At 45°C, under conditions of a charging cutoff voltage of 4.3V and a discharging cutoff voltage of 3.0V, the rechargeable battery cells were subjected to 100 charge-discharge cycles of constant current charging at 0.5CA, constant voltage charging at 0.05CA, and constant current discharging at 0.5CA to test cycle life. After 100 cycles, the discharge capacity of individual cells was measured under constant current charging at 0.2 CA, constant voltage charging at 0.05 CA, and discharge at 0.2 CA. This capacity was then divided by the initial discharge capacity to obtain the capacity retention rate after 100 cycles.

[0200] <Heating Test>

[0201] In a 25°C thermostat, rechargeable battery cells according to Examples 1 to 7 and Comparative Examples 1 to 10 were charged at a constant current to 4.42V with a design capacity of 0.1CA, and then charged at a constant voltage to 0.05CA at 4.42V. Subsequently, the battery cells were discharged at a constant current of 0.1CA to 3.0V. Additionally, in the 25°C thermostat, after performing a cycle of constant current charging at 0.2CA, constant voltage charging at 0.05CA, and constant current discharging at 0.2CA under charging cutoff voltage conditions of 4.42V and discharging cutoff voltage of 3.0V, the battery cells were recharged at constant current / constant voltage to 4.42V, and this was considered the initial battery cell. These rechargeable battery cells were placed in a thermostat heated to 165°C for 1 hour, and any instance where the voltage of a battery cell dropped to 4.3V or less was considered an "abnormal occurrence," and the abnormal occurrence rate was evaluated over 10 battery tests.

[0202] <Nail Penetration Test>

[0203] A nail penetration test was performed by penetrating the initial battery cell at its center with a nail (stainless steel or soft iron) with a diameter of 3 mm at a speed of 50 mm / s. An "abnormality" was defined as the external temperature of the battery cell reaching 50°C or higher within 5 seconds after nail penetration, and the abnormality rate was evaluated across 10 battery tests.

[0204] Overcharge Test

[0205] After charging the aforementioned initial battery cells to 12V at 3CA under constant current, and then charging them for 10 minutes under constant voltage after reaching 12V, if the external temperature of the battery cells reaches 50°C or higher, this situation is considered an "abnormal occurrence". The abnormal occurrence rate is evaluated in 10 battery tests.

[0206] <Evaluation Results>

[0207] Table 1 shows the type, physical properties, and location of the inorganic or endothermic particles used in the above examples and comparative examples. Additionally, Table 2 shows the evaluation results of the rechargeable battery cells based on Examples 1 to 7 and Comparative Examples 1 to 10.

[0208] (Table 1)

[0209]

[0210]

[0211] (Table 2)

[0212]

[0213] <Consideration of Examples and Comparative Examples>

[0214] Referring to the results in Table 2, in Examples 1 to 7, compared to Comparative Examples 1 to 10, even under conditions that easily raise the internal battery temperature (such as external impacts like pinning or overcharging), the incidence of abnormalities due to increased internal battery temperature was sufficiently suppressed to a low level. These results demonstrate that the composite particles, as heat-absorbing particles according to the present invention, sufficiently suppress the internal temperature of the non-aqueous electrolyte rechargeable battery cell comprising the composite particles to a low level.

[0215] Additionally, Examples 1 to 7 include composite particles according to the invention in the positive or negative electrode, but exhibit a single cell resistance of 1.5 Ω or less, which is equal to or less than the single cell resistance of Comparative Example 1 without the composite particles.

[0216] Furthermore, referring to the results of each example, the same effect is achieved even when the type or amount of raw material used for modification changes, or when the location containing the composite particles changes.

[0217] On the other hand, in Comparative Example 2, which only contains acetylene black particles, the resistance of the battery cell was reduced, but there was no effect on reducing the occurrence rate of anomalies.

[0218] In Comparative Example 3 or Comparative Example 5, which used unmodified metal hydroxide, the anomaly rate was not sufficiently suppressed, and the cell resistance also increased.

[0219] In addition, in Comparative Example 4 using unmodified composite particles, the cell resistance was suppressed to a low level, but the anomaly rate increased, indicating that the degree of modification of the composite particles treated by modification is important.

[0220] Furthermore, in Comparative Example 6, which used pseudoboehmite with a degree of modification within the optimal range, the anomaly rate was suppressed to a low level, but the cell resistance increased.

[0221] In Comparative Examples 7 to 10, which used a particle mixture of modified metal hydroxide particles and conductive particles, the effects of reducing both the individual cell resistance and the rate of abnormality were worse than those of Examples 1 to 7. Therefore, the metal hydroxide particles and conductive particles are not simply mixed, but used as composite particles in which the particles themselves are bonded to each other, resulting in the present invention's effect of sufficiently suppressing the increase in individual cell resistance while simultaneously sufficiently suppressing the rise in internal battery temperature.

[0222] In this disclosure, the average particle diameter (or size) can be measured using methods well-suited to those skilled in the art, for example, by a particle size analyzer (e.g., a HORIBA LA-950 laser particle size analyzer), or by transmission electron microscopy (TEM) or scanning electron microscopy (SEM). In some embodiments, the average particle diameter value can be obtained by measuring each particle size using a dynamic light scattering method, performing data analysis, counting the number of particles in each particle size range, and calculating based on the data. In some embodiments, the average particle diameter (or size) can be measured by a microscope or a particle size analyzer and can refer to the diameter (D50) of particles having a cumulative volume of 50% in the particle size distribution. D50 refers to the average diameter (or size) of 50% of the particles in the particle size distribution (e.g., a cumulative distribution) whose cumulative volume corresponds to, and refers to the particle size value corresponding to 50% of the smallest particles in a distribution curve accumulated in order from smallest to largest particle size when the total number of particles is 100%. Furthermore, in this disclosure, when the particles are spherical, "diameter" refers to the particle diameter or average particle diameter, and when the particles are non-spherical, "diameter" refers to the major axis length or average major axis length. While the invention has been described in conjunction with exemplary embodiments now considered practical, it will be understood that the invention is not limited to the disclosed embodiments. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. Composite particles for use in non-aqueous electrolyte rechargeable batteries, said composite particles being obtained by modifying composite particles of metal hydroxide particles and conductive particles capable of endothermic reaction using a treatment agent comprising at least one of phosphoric acid, phosphonic acid, and hypophosphonic acid. in, The volume resistivity at 60 MPa pressure is greater than or equal to 0.10 Ωcm and less than or equal to 4 × 10⁻⁶. 4 Ωcm, and was measured using an MCP-PD51 under a pressure of 60 MPa. In differential scanning calorimetry, the heat absorption between 50℃ and 250℃ is greater than or equal to 150 J / g and less than or equal to 500 J / g, and The amount of P2 desorbed by thermal desorption gas chromatography-mass spectrometry from 80 °C to 1400 °C is expressed as MS1, and is greater than or equal to 300 × 10⁻⁶. -6 mol / g and less than or equal to 3000 × 10 -6 mol / g.

2. The composite particles according to claim 1, wherein, The amount of H2O desorbed by the composite particles from 80°C to 200°C, as determined by thermal desorption mass spectrometry, is expressed as MS2 and is greater than or equal to 30 × 10⁻⁶. -6 mol / g and less than or equal to 1500 × 10 -6 mol / g, and the desorbed gas ratio of MS1 / MS2 satisfies equation (1): 0.5≤MS1 / MS2≤5.0 (1).

3. The composite particles according to claim 1, wherein, The 1350 cm⁻¹ value was measured by Raman spectroscopy of the composite particles. -1 The area of ​​the nearby peak is 1580cm -1 The ratio of the nearby peak areas is greater than or equal to 0.5 and less than or equal to 3.5, and 2680 cm⁻¹ measured by Raman spectroscopy -1 The full width of the nearby half-peak is greater than or equal to 60cm -1 And less than or equal to 150cm -1 .

4. The composite particles according to claim 1, wherein, The specific surface area of ​​the composite particles, calculated based on the adsorption isotherm measured by adsorption of water vapor, is represented by BET1 and is greater than or equal to 8 m². 2 / g and less than or equal to 600m 2 / g, and The specific surface area of ​​the composite particles, calculated based on the adsorption isotherm measured by adsorbing nitrogen, is represented by BET2 and is greater than or equal to 8 m². 2 / g and less than or equal to 600m 2 / g.

5. The composite particles according to claim 4, wherein, The specific surface area ratio BET1 / BET2 satisfies equation (2): 0.2≤BET1 / BET2≤5.0 (2).

6. The composite particles according to claim 1, wherein, The amount of CH4 desorbed from the composite particles by thermal desorption gas chromatography-mass spectrometry from 80°C to 1400°C is greater than or equal to 30 × 10⁻⁶. -6 mol / g and less than or equal to 1000 × 10 -6 mol / g, and The amount of CH3OH desorbed from the composite particles by thermal desorption gas chromatography-mass spectrometry from 80℃ to 1400℃ is greater than or equal to 10×10⁻⁶. -6 mol / g and less than or equal to 3000 × 10 -6 mol / g.

7. The composite particles according to claim 1, wherein, The amount of C6H6 desorbed from the composite particles by thermal desorption gas chromatography-mass spectrometry from 80℃ to 1400℃ is greater than or equal to 1×10⁻⁶. -6 mol / g and less than or equal to 4000 × 10 -6 mol / g.

8. The composite particles according to claim 1, wherein, The metal hydroxide is aluminum hydroxide.

9. A positive electrode for a non-aqueous electrolyte rechargeable battery, the positive electrode comprising: The composite particles for a non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 8, wherein the composite particles, based on 100% of the total weight of the positive electrode mixture layer, are in the range of greater than or equal to 0.1 wt% and less than or equal to 5.0 wt%.

10. A negative electrode for a non-aqueous electrolyte rechargeable battery, said negative electrode include: The composite particles for a non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 8, wherein the composite particles, based on 100% of the total weight of the negative electrode mixture layer, are in the range of greater than or equal to 0.1 wt% and less than or equal to 5.0 wt%.

11. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, membrane, and non-aqueous electrolyte. Wherein, the positive electrode is the positive electrode for a non-aqueous electrolyte rechargeable battery according to claim 9.

12. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, membrane, and non-aqueous electrolyte. The negative electrode is the negative electrode for a non-aqueous electrolyte rechargeable battery according to claim 10.

13. A method for preparing composite particles for use in non-aqueous electrolyte rechargeable batteries, the method comprising: While heating, raw materials consisting of metal hydroxide particles capable of endothermic reaction are mixed with conductive particles to form a first composite particle of the metal hydroxide particles and the conductive particles; and The first composite particles were modified using a treatment agent. The treatment agent includes at least one of phosphoric acid, phosphonic acid, and hypophosphonic acid.

14. The method according to claim 13, wherein, The raw materials and conductive particles for the metal hydroxide particles are mixed by spray drying while being heated.

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