Heat absorbing particles and non-aqueous electrolyte rechargeable battery

Abstract

Provided are heat sink particles and nonaqueous electrolyte rechargeable batteries, the heat sink particles being at least partially modified metal hydroxide particles, wherein the amount of CH4 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 15 x 10 ‑6 mol / g and less than or equal to about 3000 x 10 ‑6 mol / g, the amount of CH3OH desorbed from about 80°C to about 1400°C is greater than or equal to about 15 x 10 ‑6 mol / g and less than or equal to about 6000 x 10 ‑6 mol / g, the amount of H2O desorbed from about 80°C to about 200°C is greater than or equal to about 30 x 10 ‑6 mol / g and less than or equal to about 1500 x 10 ‑6 mol / g, and both the specific surface area calculated by the adsorption isotherm measured by adsorption of water vapor and the specific surface area calculated by adsorption of nitrogen to the metal hydroxide particles are greater than or equal to about 8 m 2 / g and less than or equal to about 600 m 2 / g.

Description

Technical Field

[0001] This disclosure relates to endothermic particles for use in non-aqueous electrolyte rechargeable batteries and non-aqueous electrolyte rechargeable batteries. 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). While rechargeable lithium-ion batteries offer the advantage of high energy density, their use of non-aqueous electrolytes necessitates adequate safety measures. However, with the recent increase in battery size, ensuring safety has become even more crucial.

[0003] 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. Therefore, there is a possibility that the internal temperature may rise further.

[0004] Therefore, in order to ensure the safety of rechargeable lithium-ion batteries, it has been proposed to include inorganic particles with endothermic properties (such as metal hydroxide particles) in rechargeable lithium-ion batteries as endothermic particles to suppress the rise in internal temperature.

[0005] For example, Patent Document 1 discloses that endothermic alkaline inorganic particles having a specific surface area ratio of greater than or equal to about 0.45 and less than or equal to about 2.0 by adsorbing water vapor and nitrogen are included in a separator as endothermic particles to improve battery safety.

[0006] In addition, Patent Documents 2 and 3 disclose endothermic particles having a maximum endothermic peak temperature of about 270°C and less than or equal to about 360°C in DSC and a dehydration reaction temperature range of about 200°C and less than or equal to about 400°C, respectively, included in an electrolyte or a membrane.

[0007] [Existing Technical Documents]

[0008] [Patent Documents]

[0009] (Patent Document 1) Japanese Patent No. 6925368

[0010] (Patent Document 2) Japanese Unexamined Patent Publication No. 2016-162528

[0011] (Patent Document 3) Japanese Patent No. 4364940 Summary of the Invention

[0012] 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 heat-absorbing particles described in Patent Document 1.

[0013] Furthermore, within the temperature range described in Patent Documents 2 and 3, melting of the separator included in the non-aqueous electrolyte rechargeable battery and decomposition of the charging positive electrode occur.

[0014] The present invention was made in view of the above-mentioned problems, and the present invention provides heat-absorbing 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).

[0015] As a result of repeated and in-depth research by the inventors to solve the aforementioned problems, in order to suppress the rise in internal temperature of non-aqueous electrolyte rechargeable batteries, the present invention was completed only after it was deduced that it is very important to make the degree of modification of the carbon-containing functional groups on the surface of the heat-absorbing particles to be included in the non-aqueous electrolyte rechargeable battery within an appropriate range.

[0016] In other words, the heat-absorbing particles for non-aqueous electrolyte rechargeable batteries according to the embodiments are at least partially modified metal hydroxide particles.

[0017] The amount of CH4 desorbed from the metal hydroxide particles by thermal desorption gas phase mass spectrometry (TDS-MS) from about 80℃ to about 1400℃ (MS1) is greater than or equal to about 15×10⁻⁶. -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g

[0018] In metal hydroxide particles, the amount of CH3OH desorbed by TDS-MS from about 80 °C to about 1400 °C (MS2) is greater than or equal to about 15 × 10⁻⁶. -6 mol / g and less than or equal to approximately 6000 × 10 -6 mol / g

[0019] In metal hydroxide particles, the amount of H₂O desorbed by TDS-MS from about 80 °C to about 200 °C (MS₃) is greater than or equal to about 30 × 10⁻⁶. -6 mol / g and less than or equal to approximately 1500 × 10 -6 mol / g

[0020] The specific surface area (BET1) calculated from the adsorption isotherm measured via adsorbed water vapor is greater than or equal to approximately 8 m². 2 / g and less than or equal to approximately 600m 2 / g, and

[0021] The specific surface area (BET2) of the metal hydroxide particles, calculated from the adsorption isotherm measured by adsorbing nitrogen onto the particles, is greater than or equal to approximately 8 m². 2 / g and less than or equal to approximately 600m 2 / g.

[0022] The heat-absorbing particles for non-aqueous electrolyte rechargeable batteries constructed as described above have a degree of modification of the carbon-containing functional groups on the surface of the heat-absorbing particles that is limited not only by the specific surface area but also by the amount of desorption of various gases. Therefore, when the heat-absorbing particles are included in a non-aqueous electrolyte rechargeable battery, the rise in the internal temperature of the non-aqueous electrolyte rechargeable battery can be suppressed under abnormal conditions.

[0023] The specific surface area ratio (BET1 / BET2) of the heat-absorbing particles can satisfy equation (1).

[0024] 0.2≤(BET1 / BET2)≤4.0(1)

[0025] The ratio of desorbed gas from the heat-absorbing particles {(MS1+MS2) / MS3} can satisfy equation (2).

[0026] 1.0≤{(MS1+MS2) / MS3}≤10.0(2)

[0027] The amount of P2 desorbed by endothermic particles from about 80°C to about 1400°C by TDS-MS can be greater than or equal to about 5 × 10⁻⁶. -6 mol / g and less than or equal to approximately 5000 × 10⁻⁶ -6 mol / g.

[0028] The amount of C6H6 desorbed from the endothermic particles from about 80 °C to about 1400 °C by TDS-MS can be greater than or equal to about 10 × 10⁻⁶. -6 mol / g and less than or equal to approximately 5000 × 10⁻⁶ -6 mol / g.

[0029] Surface treatment agents can be used to modify heat-absorbing particles.

[0030] Examples of surface treatment agents may include silane coupling agents, titanate coupling agents, aluminate coupling agents, fatty acid surface treatment agents, phosphonic acids, or combinations thereof.

[0031] The maximum endothermic peak temperature of the endothermic particles in differential scanning calorimetry can be greater than or equal to about 60°C and less than or equal to about 300°C.

[0032] Metal hydroxide particles may include aluminum hydroxide, pseudoboehmite, boehmite, alumina, kaolinite, or combinations thereof.

[0033] According to another embodiment, the non-aqueous electrolyte rechargeable battery includes heat-absorbing particles for the non-aqueous electrolyte rechargeable battery in at least one of the positive electrode, negative electrode, separator, and non-aqueous electrolyte, wherein the heat-absorbing particles are in the range of greater than or equal to about 0.01 wt% and less than or equal to about 10.0 wt% based on the total weight of the non-aqueous electrolyte rechargeable battery of 100 wt%.

[0034] According to the present invention, the degree of modification of the carbon-containing functional groups of the heat-absorbing particles is set within an appropriate range based on the amount of carbon-containing gas desorption and the specific surface area. Therefore, when included in a non-aqueous electrolyte rechargeable battery, it is possible to suppress the rise in internal temperature of the non-aqueous electrolyte rechargeable battery caused by battery abnormalities (such as internal short circuits).

[0035] In addition, by suppressing the rise in internal temperature, battery degradation caused by the rise in internal temperature can be suppressed, thus improving cycle life. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating a non-aqueous electrolyte rechargeable battery according to an embodiment. Detailed Implementation

[0037] The specific construction of the non-aqueous electrolyte rechargeable battery according to the embodiments will be described below.

[0038] <1. Basic Structure of Non-Aqueous Electrolyte Rechargeable Batteries>

[0039] 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.

[0040] There are no particular restrictions on the shape of rechargeable lithium-ion batteries, but they can be, for example, cylindrical, prismatic, stacked, or button-shaped.

[0041] 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.

[0042] (1-1, Positive Electrode)

[0043] The positive electrode includes a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector.

[0044] The positive electrode current collector can be any material as long as it is a conductor, and the positive electrode current collector is, for example, plate-shaped or thin, and can be made of aluminum, stainless steel, nickel-plated steel, etc.

[0045] 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.

[0046] 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 Mg 0.01 O2, etc. Additionally, examples of transition metal oxides including lithium may 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 Li₂, Li-Ni based composite oxides (such as LiNiO₂), and Li-Mn based composite oxides (such as LiMn₂O₄). Examples of solid solution oxides may include Li₂. 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.

[0047] 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 containing at least one selected from carbon black, natural graphite, artificial graphite, fibrous carbon, and flake carbon.

[0048] Examples of carbon black may include furnace black, channel black, thermal crack black, Ketjen black, and acetylene black.

[0049] Examples of fibrous carbon may include carbon nanotubes and carbon nanofibers, and examples of sheet carbon include graphene and the like.

[0050] The content of the conductive agent is not particularly limited, and any content applicable to the positive electrode mixture layer of a non-aqueous electrolyte rechargeable battery can be used.

[0051] The positive electrode binder may include, for example, fluororesins (such as polyvinylidene fluoride), ethylene-containing resins (such as styrene-butadiene rubber, ethylene-propylene-diene terpolymer, 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 binding the positive electrode active material and the conductive agent to the positive electrode current collector, and there is no particular limitation.

[0052] (1 - 2. Negative electrode)

[0053] The negative electrode includes a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector.

[0054] The negative electrode current collector can be any substance as long as it is a conductor, and the negative electrode current collector can desirably be in a plate shape or thin, and made of copper, stainless steel, nickel-coated steel, etc.

[0055] The negative electrode mixture layer may at least include a negative electrode active material, and may also include a conductive agent and a negative electrode binder.

[0056] The negative electrode active material is not particularly limited as long as it can electrochemically intercalate and deintercalate lithium ions, but can 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, a mixture of fine particles of silicon (Si) or tin (Sn) or a mixture of their oxides and a graphite active material, particles of silicon or tin, an alloy including silicon or tin as a matrix material), metallic lithium, a titanium oxide compound (such as Li4Ti5O 12 )、lithium nitride, etc. As the negative electrode active material, one of the above examples can be used, or two or more can be used in combination. On the other hand, the oxide of silicon can be represented by SiO x (0 < x ≤ 2).

[0057] The conductive agent is not particularly limited as long as it is used to increase the conductivity of the negative electrode. For example, the same conductive agent as described in the positive electrode part can be used.

[0058] The negative electrode binder can be any binder capable of bonding the negative electrode active material and conductive agent to the negative electrode current collector, and there are no particular limitations. The negative electrode binder can be, for example, a metal salt of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene copolymer (SBR), carboxymethyl cellulose (CMC), etc. The binder can be used alone or in a mixture of two or more types.

[0059] (1-3, diaphragm)

[0060] 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 conventional rechargeable lithium-ion battery separators can be used arbitrarily.

[0061] 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.

[0062] (1-4, Non-aqueous electrolytes)

[0063] As the non-aqueous electrolyte, the same non-aqueous electrolyte as that conventionally used in rechargeable lithium ion batteries can be used without particular limitation. The non-aqueous electrolyte has a composition in which an electrolyte salt is included in a non-aqueous solvent, and the non-aqueous solvent is a solvent for the electrolyte. Examples of the non-aqueous solvent may include cyclic carbonates (such as propylene carbonate, ethylene carbonate, butylene 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 ethyl methyl carbonate), chain esters (such as methyl formate, methyl acetate, methyl butyrate, ethyl propionate, propyl propionate), ethers (such as tetrahydrofuran or its derivatives, 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxyethane, 1,4-dibutoxyethane, methyl diglycol dimethyl ether, ethylene glycol monopropyl ether, or propylene glycol monopropyl ether), nitriles (such as acetonitrile and benzonitrile), dioxolane or its derivatives, thioethane, sulfolane, sulfone esters or its derivatives, which may be used alone or as a mixture of two or more. 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 may be the mixing ratio that can be used in conventional rechargeable lithium ion batteries.

[0064] Examples of the electrolyte salt may include inorganic ion 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 (provided that 1 < x < 6, n = 1 or 2), LiSCN, LiBr, LiI, Li2SO4, Li2B 10 Cl 10NaClO4, 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)4NClO 4. Lithium compounds such as (C2H5)4NI, (C3H7)4NBr, (n-C4H9)4NClO4, (n-C4H9)4NI, (C2H5)4N-maleic acid ester, (C2H5)4N-benzoic acid ester, (C2H5)4N-phthalic acid ester, lithium stearyl sulfonate, lithium octyl sulfonate, lithium dodecylbenzene sulfonate, etc., can be used alone or in mixtures of two or more types. On the other hand, the concentration of the electrolyte salt can be the same as that of the non-aqueous electrolyte used in conventional rechargeable lithium-ion batteries, and there are no particular limitations. In the examples, it is desirable to use a non-aqueous electrolyte containing the above-mentioned lithium compounds (electrolyte salts) at a concentration greater than or equal to about 0.8 mol / L and less than or equal to about 1.5 mol / L.

[0065] On the other hand, various additives can be added to non-aqueous electrolytes. Examples of such additives include negative electrode additives, positive electrode 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.

[0066] <2. Characteristic structure of the non-aqueous electrolyte rechargeable battery according to the embodiment>

[0067] The following describes the characteristic construction of a non-aqueous electrolyte rechargeable battery according to an embodiment.

[0068] In addition to the aforementioned components, the positive electrode mixture layer of the non-aqueous electrolyte rechargeable battery according to this embodiment also includes heat-absorbing particles.

[0069] These endothermic particles include metal hydroxides that can absorb heat through endothermic reactions.

[0070] There are no particular limitations on the metal hydroxides used, as long as they can induce an endothermic reaction. Examples of metal hydroxides include aluminum hydroxide, pseudoboehmite, boehmite, alumina, or kaolinite. These can be used alone or together.

[0071] On the other hand, the average initial particle size of the endothermic particles can be expected to be greater than or equal to about 0.05 μm and less than or equal to about 50 μm, and more preferably greater than or equal to about 0.1 μm and less than or equal to about 10 μm.

[0072] The heat-absorbing particles according to this embodiment are made of metal hydroxide particles that are at least partially modified with carbon functional groups, and the specific surface area and the degree of modification of the carbon functional groups of the heat-absorbing particles are within the following ranges.

[0073] The specific surface area (called BET1), calculated from the adsorption isotherm measured by adsorbing water vapor onto endothermic particles, can be greater than or equal to approximately 8 m². 2 / g and less than or equal to approximately 600m 2 / g, and at the same time, the specific surface area (called BET2) calculated from the adsorption isotherm measured by adsorbing nitrogen gas onto metal hydroxide particles can be greater than or equal to about 8m². 2 / g and less than or equal to approximately 600m 2 / g.

[0074] BET1 can be greater than or equal to approximately 10m 2 / g and less than or equal to approximately 400m 2 / g, or greater than or equal to approximately 12m 2 / g and less than or equal to approximately 210m 2 / g.

[0075] BET2 can be greater than or equal to approximately 9m 2 / g and less than or equal to approximately 400m 2 / g, or greater than or equal to approximately 10m 2 / g and less than or equal to approximately 200m 2 / g.

[0076] In addition, the specific surface area ratio (BET1 / BET2) (which is the ratio between BET1 and BET2) can be greater than or equal to about 0.2 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 3.5.

[0077] The carbon-containing functional groups can be primarily CH3 and CH2OH groups. The degree of modification by the carbon-containing functional groups can be defined by the amount of gas desorbed from the endothermic particles when the particles are heated from about 80°C to about 1400°C (desorption amount), and the desorption amounts of the following gases derived from the above functional groups satisfy the following ranges.

[0078] The amount of CH4 desorbed (called MS1) can be greater than or equal to about 15 × 10⁻⁶. -6 mol / g and less than or equal to approximately 3000 × 10 -6mol / g; the amount of CH3OH desorbed (called MS2) can be greater than or equal to approximately 15 × 10 mol / g. -6 mol / g and less than or equal to approximately 6000 × 10 -6 mol / g (e.g., greater than or equal to about 50 × 10⁻⁶) -6 mol / g and less than or equal to approximately 6000 × 10 -6 mol / g); and the amount of H2O desorbed (called MS3) can be greater than or equal to approximately 30 × 10⁻⁶ mol / g; -6 mol / g and less than or equal to approximately 1500 × 10 - 6 mol / g.

[0079] MS1 can be greater than or equal to approximately 20 × 10 -6 mol / g or greater than or equal to approximately 30 × 10 -6 mol / g.

[0080] MS2 can be greater than or equal to approximately 100 × 10 -6 mol / g or greater than or equal to approximately 200 × 10 -6 mol / g.

[0081] MS3 can be greater than or equal to approximately 50 × 10 -6 mol / g and less than or equal to approximately 1000 × 10 -6 mol / g, or greater than or equal to approximately 100 × 10⁻⁶ -6 mol / g and less than or equal to approximately 750 × 10 -6 mol / g.

[0082] Furthermore, the ratio of these desorption amounts {(MS1+MS2) / MS3} can be greater than or equal to about 1.0 and less than or equal to about 10.0, greater than or equal to about 2.0 and less than or equal to about 9.0, or greater than or equal to about 2.5 and less than or equal to about 8.0.

[0083] In addition, when phosphonic acid is used to modify endothermic particles, it can impart fire extinguishing function to the endothermic particles.

[0084] Therefore, the amount of P2 desorbed from the endothermic particles by TDS-MS from about 80°C to about 1400°C (referred to as MS4) can be greater than or equal to about 5 × 10⁻⁶. -6 mol / g and less than or equal to approximately 5000 × 10⁻⁶ -6 mol / g, greater than or equal to approximately 20 × 10 -6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g, or greater than or equal to approximately 40 × 10 -6 mol / g and less than or equal to approximately 1000 × 10-6 mol / g.

[0085] Furthermore, when endothermic particles are modified with functional groups containing phenyl groups, the metal hydroxide particles are easily dispersed in the solvent during the preparation of slurries (such as positive electrode mixture slurries).

[0086] Therefore, the amount of C6H6 desorbed by endothermic particles by TDS-MS at approximately 80°C to approximately 1400°C (referred to as MS5) can be greater than or equal to approximately 10 × 10⁻⁶. -6 mol / g and less than or equal to approximately 5000 × 10⁻⁶ -6 mol / g, greater than or equal to approximately 20 × 10 - 6 mol / g and less than or equal to approximately 3000 × 10 -6 mol / g, or greater than or equal to approximately 40 × 10 -6 mol / g and less than or equal to approximately 1500 × 10 -6 mol / g.

[0087] When the total amount of heat-absorbing particles is 100 wt%, the total content of modified molecules contained in the heat-absorbing 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%.

[0088] Based on a total weight of 100 wt% of the positive electrode mixture layer, the content of endothermic particles in the positive electrode mixture layer for non-aqueous electrolyte rechargeable batteries may be in the range of greater than or equal to about 0.05 wt% and less than or equal to about 10.0 wt%, greater than or equal to about 0.1 wt% and less than or equal to about 5.0 wt%, or greater than or equal to about 0.5 wt% and less than or equal to about 2.0 wt%.

[0089] Based on a total weight of 100 wt% of the non-aqueous electrolyte rechargeable battery, the content of heat-absorbing particles for the non-aqueous electrolyte rechargeable battery can vary depending on the intended use of the non-aqueous electrolyte rechargeable battery, and is therefore not limited to the following range. However, for example, based on a total weight of 100 wt% of the non-aqueous electrolyte rechargeable battery, the content of heat-absorbing particles for the non-aqueous electrolyte rechargeable battery included in the non-aqueous electrolyte rechargeable battery can be in the range of greater than or equal to about 0.01 wt% and less than or equal to about 10.0 wt% (e.g., 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%).

[0090] <3. Method for manufacturing a non-aqueous electrolyte rechargeable battery according to the embodiment>

[0091] The following describes a method for manufacturing rechargeable lithium-ion batteries.

[0092] The heat-absorbing particles for non-aqueous electrolyte rechargeable batteries according to this embodiment can be manufactured by modifying metal hydroxide particles made of metal hydroxide.

[0093] Examples of methods for modifying metal hydroxide particles may include immersing the metal hydroxide particles in a modifier (e.g., a surface modifier or surface treatment agent) for a predetermined time period.

[0094] Examples of surface modifiers include silane coupling agents, titanate coupling agents, aluminate coupling agents, fatty acid surface treatment agents (e.g., advanced fatty acid surface treatment agents having 10 to 60 carbon atoms), and phosphonic acids (such as phosphonic acid and phenylphosphonic acid).

[0095] By immersing metal hydroxide particles in these modifiers, the surface and interior of the metal hydroxide particles are modified by functional groups derived from these modifiers.

[0096] The positive electrode is manufactured as follows. First, a positive electrode slurry is formed by dispersing a mixture of positive electrode active material, conductive agent, positive electrode binder, and heat-absorbing particles for non-aqueous electrolyte rechargeable batteries in a desired proportion in a solvent 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 also 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.

[0097] The negative electrode is manufactured 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 drying it. Then, the negative electrode material mixture layer is pressed using a press to achieve the desired density. Thus, the negative electrode is manufactured.

[0098] 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, stacked, 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. Thus, a rechargeable lithium-ion battery is manufactured.

[0099] <4. Effects of this embodiment>

[0100] The non-aqueous electrolyte rechargeable battery constructed as described above can sufficiently suppress the rise in internal battery temperature even under abnormal conditions. Therefore, the safety of the non-aqueous electrolyte rechargeable battery can be ensured, while maintaining high battery characteristics (such as cycle life).

[0101] <5. Another embodiment>

[0102] This disclosure is not limited to the foregoing embodiments.

[0103] In the foregoing embodiments, the case where the positive electrode includes heat-absorbing particles for a non-aqueous electrolyte rechargeable battery according to the present disclosure has been described. However, the negative electrode may include heat-absorbing particles for a non-aqueous electrolyte rechargeable battery, or the separator or electrolyte may include heat-absorbing particles for a non-aqueous electrolyte rechargeable battery.

[0104] When the negative electrode includes endothermic particles for a non-aqueous electrolyte rechargeable battery, the content of these particles relative to the entire negative electrode can be within the same range as that of the positive electrode. When the separator includes endothermic particles for a non-aqueous electrolyte rechargeable battery, when the total weight of the separator is 100 wt%, the content of these endothermic particles can be greater than or equal to about 0.5 wt% and less than or equal to about 20.0 wt%. When the electrolyte includes endothermic particles for a non-aqueous electrolyte rechargeable battery, when the total weight of the electrolyte is 100 wt%, the content of these endothermic 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%. On the other hand, when the separator or electrolyte includes endothermic particles, the average initial particle size of the endothermic particles can be greater than or equal to about 0.1 μm and less than or equal to about 10 μm.

[0105] Furthermore, the present invention is not limited to these embodiments, but can be modified in various ways without departing from the purpose.

[0106]

Example

[0107] 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.

[0108] <Manufacturing of heat-absorbing particles for non-aqueous electrolyte rechargeable batteries>

[0109] (Example 1)

[0110] A treatment solution was prepared by dissolving 3.0 g of triethoxyvinylsilane in a mixed solution of 50 cc ethanol and purified water (volume ratio 1:1). 1.0 g of aluminum hydroxide granules (BET1:205m) were then added. 2 / g, BET2: 200m 2 The modified aluminum hydroxide particles (A) were dispersed in a treatment solution, then heat-treated at 80°C for 4 hours and vacuum dried to obtain modified aluminum hydroxide particles (A). Here, the metal hydroxide particles used in each example have an average initial particle size greater than or equal to 5 μm and less than or equal to 12 μm.

[0111] (Example 2)

[0112] A treatment solution was prepared by dissolving 3.0 g of triethoxyvinylsilane in a mixed solution of 50 cc ethanol and purified water (volume ratio 1:1). 1.0 g of activated alumina particles (BET1:300m) were then added. 2 / g, BET2: 270m 2 / g (manufactured by Iwatani Chemical Industry Co., Ltd.) is dispersed in a treatment solution, and then heat-treated at 80°C for 4 hours and vacuum dried to obtain modified active alumina particles (A).

[0113] (Example 3)

[0114] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 Modified pseudoboehmite particles (A) were obtained in the same manner as in Example 1, except that 3.0 g of p-styrenetrimethoxysilane (manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (prepared by dissolving 3.0 g of p-styrenetrimethoxysilane in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1)).

[0115] (Example 4)

[0116] In addition to 1.0g of magnesium hydroxide granules (BET1: 160m) 2 / g, BET2: 150m 2Modified magnesium hydroxide particles (A) were obtained in the same manner as in Example 1, except that 3.0 g of 3-acryloyloxypropyltrimethoxysilane (manufactured by Iwatani Chemical Industry Co., Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of 3-acryloyloxypropyltrimethoxysilane in a mixed solution of 50 cc of ethanol and purified water (volume mixing ratio of 1:1)).

[0117] (Example 5)

[0118] In addition to 1.0g of kaolinite particles (Al2Si2O5(OH)4, BET1:120m) 2 / g, BET2: 110m 2 Modified kaolinite particles (A) were obtained in the same manner as in Example 1, except that 3.0 g of 3-aminopropyltrimethoxysilane (manufactured by Iwatani Chemical Industry Co., Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of 3-aminopropyltrimethoxysilane in a mixed solution of 50 cc of ethanol and purified water (volume mixing ratio of 1:1)).

[0119] (Example 6)

[0120] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 Modified pseudoboehmite particles (B) were obtained in the same manner as in Example 1, except that 0.3 g of p-styrenetrimethoxysilane (manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (prepared by dissolving 0.3 g of p-styrenetrimethoxysilane in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1)).

[0121] (Example 7)

[0122] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 Modified pseudoboehmite particles (C) were obtained in the same manner as in Example 1, except that 3.0 g of triisostearate titanate isopropyl ester was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of triisostearate titanate isopropyl ester in a mixed solution of 50 cc of ethanol and purified water (volume mixing ratio of 1:1)).

[0123] (Example 8)

[0124] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2Modified pseudoboehmite particles (D) were obtained in the same manner as in Example 1, except that the sodium stearate (3.0 g, manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of sodium stearate in a mixed solution of 50 cc of ethanol and purified water (volume mixing ratio of 1:1)).

[0125] (Example 9)

[0126] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 / g, manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 5.0g of phenylphosphonic acid in a mixed solution of 50cc of ethanol and purified water (volume mixing ratio of 1:1) to obtain modified pseudoboehmite particles (E) in the same manner as in Example 1.

[0127] (Example 10)

[0128] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 / g, manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0g phenylphosphonic acid in a mixed solution of 50cc ethanol and purified water (volume mixing ratio of 1:1) to obtain modified pseudoboehmite particles (F) in the same manner as in Example 1.

[0129] (Examples 11 to 13)

[0130] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 / g, manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 1.0g phenylphosphonic acid in a mixed solution of 50cc ethanol and purified water (volume mixing ratio of 1:1) to obtain modified pseudoboehmite particles (G) in the same manner as in Example 1.

[0131] (Compare Examples 2 to 8)

[0132] Use the heat-absorbing particles described in Table 1.

[0133] (Table 1)

[0134] heat-absorbing particles Sample name, manufacturer Comparison Example 2 Aluminum hydroxide granules 1 RA-40, Iwatani Chemical Industry Co., Ltd. Comparison Example 3 Aluminum hydroxide particles 2 RH40, Iwatani Chemical Industry Co., Ltd. Compare Example 4 Magnesium hydroxide granules 1 <![CDATA[ECOMAG TM Z-10, Tateho Chemical Industry Co., Ltd. Compare Example 5 Magnesium hydroxide granules 2 MTK-30, Iwatani Chemical Industry Co., Ltd. Comparison Example 6 Kaolinite particles Kaolinite, Sigma-Aldrich Chemicals Compare Example 7 Pseudoboehmite particles PB-R, Cis Chemicals Ltd. Compare Example 8 Boehmite particles BG-601, Anhui Yishitong Materials Technology Co., Ltd.

[0135] (Compare with Example 9)

[0136] In addition to 1.0g of aluminum hydroxide granules (BET1: 3.3m) 2 / g, BET2: 3.2m 2 Modified aluminum hydroxide particles (B) were obtained in the same manner as in Example 1, except that 3.0 g of p-styrenetrimethoxysilane (manufactured by Iwatani Chemical Industry Co., Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of p-styrenetrimethoxysilane in a mixed solution of 50 cc of ethanol and purified water (volume mixing ratio of 1:1)).

[0137] (Compare with Example 10)

[0138] In addition to 1.0g of magnesium hydroxide granules (BET1: 2.0m) 2 / g, BET2: 2.4m 2 Modified magnesium hydroxide particles (B) were obtained in the same manner as in Example 1, except that 3.0 g of p-styrenetrimethoxysilane (manufactured by Iwatani Chemical Industry Co., Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 3.0 g of p-styrenetrimethoxysilane in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1)).

[0139] (Compare with Example 11)

[0140] In addition to 1.0g of boehmite particles (BET1: 15.2m) 2 / g, BET2: 10.1m 2 Modified boehmite particles (B) were obtained in the same manner as in Example 1, except that 3.0 g of p-styrenetrimethoxysilane (manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (prepared by dissolving 3.0 g of p-styrenetrimethoxysilane in a mixed solution of 50 cc ethanol and purified water (volume mixing ratio of 1:1)).

[0141] (Compare with Example 12)

[0142] In addition to 1.0g of pseudoboehmite particles (BET1: 407m) 2 / g, BET2: 377m 2 / g, manufactured by Cis Chemicals Ltd.) was dispersed in a treatment solution (which was prepared by dissolving 0.05g phenylphosphonic acid in a mixed solution of 50cc ethanol and purified water (volume mixing ratio of 1:1) to obtain surface-modified pseudoboehmite particles (H) in the same manner as in Example 1.

[0143] <Manufacturing of the positive electrode>

[0144] (Examples 1 through 10 and Comparative Examples 2 through 12)

[0145] LiCoO2, acetylene black, polyvinylidene fluoride, and each of the endothermic particles shown in Table 2 for non-aqueous electrolyte rechargeable batteries were mixed in a weight ratio of 97.0:1.0:1.3:0.7 and dispersed in N-methyl-2-pyrrolidone solvent to prepare a positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry was coated onto one or both surfaces of an aluminum current collector foil and dried to achieve a surface area of ​​20.0 mg / cm² after drying. 2 The coating amount (surface density) of the mixture is then pressed with a roller press to produce each positive electrode with a mixture layer density of 4.15 g / cc.

[0146] (Examples 11 through 13 and comparison example 1)

[0147] Each positive electrode was manufactured in the same manner as in Example 1, except that a positive electrode mixture slurry was prepared by mixing LiCoO2, acetylene black and polyvinylidene fluoride in a weight ratio of 97.7:1.0:1.3 and dispersing it in an N-methyl-2-pyrrolidone solvent.

[0148] <Manufacturing of the negative electrode>

[0149] (Examples 1 to 10, Examples 12 to 13, and Comparative Examples 1 to 12)

[0150] A negative electrode mixture slurry was prepared by dissolving and dispersing artificial graphite, sodium carboxymethyl cellulose (CMC), and a styrene-butadiene aqueous dispersion 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 or both surfaces of a copper foil and dried to achieve a surface finish of 10.5 mg / cm² on each surface after drying. 2 The coating amount (surface density) of the mixture is then pressed with a roller press to produce a mixture layer density of 1.65 g / cc to manufacture the negative electrode.

[0151] (Example 11)

[0152] The negative electrode is manufactured in the same manner as in Example 1, except that the negative electrode mixture slurry is prepared by dissolving and dispersing artificial graphite, sodium carboxymethyl cellulose (CMC), styrene-butadiene aqueous dispersion and the endothermic particles for non-aqueous electrolyte rechargeable batteries shown in Table 2 in an aqueous solvent at a weight ratio of 96.5:1.0:1.5:1.0.

[0153] Manufacturing of rechargeable battery cells

[0154] (Examples 1 to 11 and Comparative Examples 1 to 12)

[0155] Multiple positive and negative electrodes are stacked with a porous polypropylene separator between the positive and negative electrodes to create an electrode stack with a designed battery capacity of 300 mAh. A rechargeable battery cell 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; electrolyte is injected into it; 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.

[0156] (Example 12)

[0157] 30 parts by weight of pseudoboehmite particles (G) and 0.3 parts by weight of an aqueous solution of aminopolycarboxylic acid were mixed in 100 parts by weight of ion-exchanged water and then treated with a bead mill to adjust the average particle size (D50) to 1.0 μm or less to prepare a uniform composition for forming an endothermic layer.

[0158] Subsequently, the rechargeable battery cell was manufactured in the same manner as in Example 1, except that a 2 μm thick surface layer including pseudoboehmite particles (G) was formed on the polypropylene porous membrane by coating the composition for forming the heat-absorbing layer onto the aforementioned polypropylene porous membrane using a micro-gravure coating machine and drying at 80°C to remove ion-exchanged water.

[0159] (Example 13)

[0160] Except for preparing a composition for forming the heat-absorbing layer by using 5 parts by weight of pseudoboehmite particles (G) based on 100 parts by weight of a non-aqueous electrolyte having the same composition, the rechargeable battery cell was manufactured in the same manner as in Example 1.

[0161] Evaluation of the physical properties of endothermic particles

[0162] The following evaluation and comparison examples use endothermic particles for non-aqueous electrolyte rechargeable batteries.

[0163] (Specific surface area (BET) of endothermic particles)

[0164] The specific surface area (BET (BET1 or BET2), which is the specific surface area calculated by means of the adsorption isotherm measured via adsorption of water vapor or nitrogen, was measured using a gas adsorption capacity measuring device (BELSORP, Microtrac Bell Co., Ltd.) according to JIS K6217-2).

[0165] (Maximum endothermic peak of the endothermic particles)

[0166] The maximum endothermic peak temperature of each endothermic particle was measured using a differential scanning calorimetry (DSC, Hitachi High-Tech Co., Ltd.) device and by heating at a rate of 5 K / min according to JIS K7121. According to an embodiment, the maximum endothermic peak temperature of the endothermic particle is greater than or equal to about 60°C and less than or equal to about 300°C (e.g., greater than or equal to about 120°C and less than or equal to about 200°C, or greater than or equal to about 130°C and less than or equal to about 175°C).

[0167] (The mass of the desorbed gas from the endothermic particles)

[0168] Thermal desorption gas chromatography-mass spectrometry (TDS-MS) was performed using a thermal desorption gas chromatography-mass spectrometer (TDS-1200, ESCO, Ltd.) to measure and analyze the desorption amounts of methane, methanol, benzene, diphosphorus, and water molecules as follows.

[0169] In TDS, endothermic particles were positioned 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 sample surface temperature. 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.

[0170] TDS was used to measure the amount (μmol / g) of each gas desorbed from endothermic particles during a temperature increase from 80°C to 1400°C. The mass number [M / z] used to analyze the measurement results was 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 was used to obtain the amount of desorbed H2O (MS3).

[0171] <Confirmed heat generation at 150°C or lower with the coexistence of endothermic particles and electrolytes>

[0172] 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 endothermic peak was examined in the same way as the aforementioned method for measuring the maximum endothermic peak of the endothermic particles to check whether an exothermic peak was found at 150°C or lower. Comparative Examples 1 to 11 showed obvious exothermic peaks near 100°C, but Examples 1 to 13 did not show exothermic peaks.

[0173] <Evaluation of Rechargeable Battery Cells>

[0174] (Cyclic Characteristics)

[0175] In a 25°C thermostat, rechargeable battery cells according to Examples 1 to 13 and Comparative Examples 1 to 12 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. Additionally, in the 25°C thermostat, the initial discharge capacity of the battery cells after the first cycle was measured by 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. 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 by 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 constant current discharging at 0.2 CA, and divided by the initial discharge capacity to obtain the capacity retention rate after 100 cycles.

[0176] (Heating Test)

[0177] In a 25°C thermostat, rechargeable battery cells according to Examples 1 to 13 and Comparative Examples 1 to 12 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 with a voltage of 4.42V. Subsequently, the battery cells were discharged at a constant current of 0.1CA to 3.0V. Furthermore, 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 conditions of a charging cutoff voltage of 4.42V and a discharging cutoff voltage of 3.0V, the battery cells were recharged at a 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 lower was considered an "abnormal occurrence," and the abnormal occurrence rate was evaluated in 10 battery tests.

[0178] (Nail puncture test)

[0179] 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 "abnormal occurrence" was defined as the external temperature of the battery cell reaching 50°C or higher 5 seconds after nail penetration, and the abnormal occurrence rate was evaluated across 10 battery tests.

[0180] (Overcharge test)

[0181] An "abnormal occurrence" is defined as the external temperature of the battery cells reaching 50°C or higher after being charged to 12V at 3CA under constant current and then charged for 10 minutes under constant voltage after reaching 12V. The abnormal occurrence rate is evaluated in 10 battery tests.

[0182] (Experimental Results)

[0183] Table 2 shows the type, physical properties, and location of the endothermic particles used in the above examples and comparative examples.

[0184] In addition, Table 3 shows the evaluation results of Examples 1 to 13 and Comparative Examples 1 to 12.

[0185] (Table 2)

[0186]

[0187]

[0188] (Table 3)

[0189]

[0190]

[0191] <Consideration of Examples and Comparative Examples>

[0192] Referring to the results in Table 3, compared with the battery cells according to Comparative Examples 1 to 12, the non-aqueous electrolyte rechargeable battery cells according to Examples 1 to 13 sufficiently suppressed the occurrence rate of anomalies under various conditions of increased internal temperature of the battery cell.

[0193] Although the endothermic particles for non-aqueous electrolyte rechargeable batteries shown in Table 2 (Comparative Examples 3, 5, and 7) have specific surface areas within the expected range, as shown in Table 3, they exhibit extremely high anomaly rates compared to Examples 1 through 13.

[0194] Based on the results, in order to obtain endothermic particles for non-aqueous electrolyte rechargeable batteries, the endothermic particles should have sufficient endothermic performance in the battery at a relatively low temperature of 200°C or lower, and the degree of modification of carbon functional groups (found by the amount of desorbed gas shown in Table 2) and specific surface area should be within a predetermined range.

[0195] One reason for this result is that when endothermic particles with a high degree of carbon functional group modification suppress the reaction between the metal hydroxide contained in the endothermic particles and the electrolyte when the internal temperature of the battery rises, a sufficient amount of metal hydroxide that contributes to the endothermic reaction can be ensured.

[0196] Since no non-aqueous electrolyte rechargeable battery has been reported to date that can exhibit such performance, as shown in Table 3, a non-aqueous electrolyte rechargeable battery that can limit the aforementioned anomaly rate to 20% or less (specifically, 10% or less) based on the aforementioned heating test can be considered to contain endothermic particles for the non-aqueous electrolyte rechargeable battery according to the present invention.

[0197] In addition, non-aqueous electrolyte rechargeable battery cells exhibiting an abnormality rate of 30% or less (specifically, 20% or less) in nail puncture tests, or non-aqueous electrolyte rechargeable battery cells exhibiting an abnormality rate of 30% or less (specifically, 20% or less) in overcharge tests, are also considered to contain endothermic particles for use in non-aqueous electrolyte rechargeable batteries according to the present invention.

[0198] Furthermore, the heat-absorbing particles for non-aqueous electrolyte rechargeable batteries according to Examples 1 to 13 have a relatively large specific surface area and a maximum endothermic peak temperature of less than 200°C. Therefore, before the internal temperature of the non-aqueous electrolyte rechargeable battery cell reaches 200°C, an endothermic reaction occurs due to the heat-absorbing particles used in the non-aqueous electrolyte rechargeable battery, suppressing the internal temperature of the non-aqueous electrolyte rechargeable battery cell including the heat-absorbing particles to below 200°C, wherein the battery does not deteriorate.

[0199] In this disclosure, the average particle size (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 size value can be obtained by measuring the average particle size value using a dynamic light scattering method, performing data analysis, counting the number of particles in each particle size range, and performing calculations based on the data. In some embodiments, the average particle size (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 particles whose cumulative volume corresponds to 50% of the particle size distribution (e.g., a cumulative distribution), and refers to the particle size value corresponding to 50% starting from the smallest particle in a distribution curve accumulated in order from the smallest to the 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 size or average particle size, and when the particles are non-spherical, "diameter" refers to the length of the major axis or the average length of the major axis.

[0200] 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. Heat-absorbing particles for non-aqueous electrolyte rechargeable batteries, said heat-absorbing particles being at least partially modified by a surface treatment agent comprising carbon-containing functional groups, such as aluminum hydroxide particles, pseudoboehmite particles, boehmite particles, alumina particles, kaolinite particles, magnesium hydroxide particles, or combinations thereof. in, The amount of CH4 desorbed by the endothermic particles from 80℃ to 1400℃ via thermal desorption gas chromatography-mass spectrometry (MS1) is greater than or equal to 15 × 10⁻⁶. -6 mol / g and less than or equal to 3000 × 10 -6 mol / g The amount of CH3OH desorbed by thermal desorption gas chromatography-mass spectrometry from 80℃ to 1400℃ (MS2) is greater than or equal to 15 × 10⁻⁶. -6 mol / g and less than or equal to 6000 × 10 -6 mol / g The amount of H2O desorbed by thermal desorption gas chromatography-mass spectrometry from 80℃ to 200℃ (MS3) is greater than or equal to 30 × 10⁻⁶. -6 mol / g and less than or equal to 1500 × 10 -6 mol / g The specific surface area BET1, calculated from the adsorption isotherm measured via adsorbed water vapor, is greater than or equal to 8 m². 2 / g and less than or equal to 600m 2 / g, and The specific surface area BET2 of the endothermic particles, calculated via adsorption isotherms measured by adsorbing nitrogen onto the particles, is greater than or equal to 8 m². 2 / g and less than or equal to 600m 2 / g.

2. The heat-absorbing particles according to claim 1, wherein, The specific surface area ratio (BET1 / BET2) of the heat-absorbing particles satisfies equation (1): 0.2≤(BET1 / BET2)≤4.0(1).

3. The heat-absorbing particles according to claim 1, wherein, The ratio of the amount of desorbed gas in the heat-absorbing particles {(MS1+MS2) / MS3} satisfies equation (2): 1.0≤{(MS1+MS2) / MS3}≤10.0 (2).

4. The heat-absorbing particles according to claim 1, wherein, The amount of P2 desorbed by the endothermic particles from 80℃ to 1400℃ via thermal desorption gas phase mass spectrometry is greater than or equal to 5×10⁻⁶. -6 mol / g and less than or equal to 5000 × 10 -6 mol / g.

5. The heat-absorbing particles according to claim 1, wherein, The amount of C6H6 desorbed from the endothermic particles by thermal desorption gas phase mass spectrometry from 80℃ to 1400℃ is greater than or equal to 10×10⁻⁶. -6 mol / g and less than or equal to 5000 × 10 -6 mol / g.

6. The heat-absorbing particles according to claim 1, wherein, The surface treatment agent includes silane coupling agents, titanate coupling agents, aluminate coupling agents, fatty acid surface treatment agents, phosphonic acids, or combinations thereof.

7. The heat-absorbing particles according to claim 1, wherein, The maximum endothermic peak temperature of the endothermic particles in differential scanning calorimetry is greater than or equal to 60°C and less than or equal to 300°C.

8. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, diaphragm, and non-aqueous electrolyte. The positive electrode comprises heat-absorbing particles for the non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 7, wherein the heat-absorbing particles are in the range of greater than or equal to 0.01 wt% and less than or equal to 10.0 wt% based on the total weight of the non-aqueous electrolyte rechargeable battery of 100 wt%.

9. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, diaphragm, and non-aqueous electrolyte. The negative electrode includes heat-absorbing particles for the non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 7, wherein the heat-absorbing particles are in the range of greater than or equal to 0.01 wt% and less than or equal to 10.0 wt% based on the total weight of the non-aqueous electrolyte rechargeable battery of 100 wt%.

10. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, diaphragm, and non-aqueous electrolyte. The separator includes heat-absorbing particles for the non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 7, wherein the heat-absorbing particles are in the range of greater than or equal to 0.01 wt% and less than or equal to 10.0 wt% based on the total weight of the non-aqueous electrolyte rechargeable battery of 100 wt%.

11. A non-aqueous electrolyte rechargeable battery, said non-aqueous electrolyte rechargeable battery comprising: Positive electrode, negative electrode, diaphragm, and non-aqueous electrolyte. The non-aqueous electrolyte includes heat-absorbing particles for the non-aqueous electrolyte rechargeable battery according to any one of claims 1 to 7, wherein the heat-absorbing particles are in the range of greater than or equal to 0.01 wt% and less than or equal to 10.0 wt% based on the total weight of the non-aqueous electrolyte rechargeable battery of 100 wt%.

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