WO2023102793A1 - 二次电池及包含其的用电装置 - Google Patents

二次电池及包含其的用电装置 Download PDF

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WO2023102793A1
WO2023102793A1 PCT/CN2021/136599 CN2021136599W WO2023102793A1 WO 2023102793 A1 WO2023102793 A1 WO 2023102793A1 CN 2021136599 W CN2021136599 W CN 2021136599W WO 2023102793 A1 WO2023102793 A1 WO 2023102793A1
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secondary battery
battery
particles
carboxylate
hydroxypyridine
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PCT/CN2021/136599
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English (en)
French (fr)
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邹海林
陈培培
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宁德时代新能源科技股份有限公司
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Priority to CN202180098375.4A priority Critical patent/CN117321818A/zh
Priority to EP21966717.7A priority patent/EP4318701A1/en
Priority to PCT/CN2021/136599 priority patent/WO2023102793A1/zh
Publication of WO2023102793A1 publication Critical patent/WO2023102793A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of secondary batteries, in particular to a secondary battery and an electrical device including the same.
  • Secondary batteries are widely used due to their outstanding features such as high energy density, no pollution, and long service life.
  • the electrolyte is sensitive to moisture, so it is easy to generate acidic substances, which can damage battery performance.
  • acidic substances are not resistant to electrochemical oxidation and reduction, so they will consume active lithium in the battery, reduce Coulombic efficiency, deteriorate battery internal resistance, reduce battery capacity and increase gas production, etc.; and acidic substances will also etch the SEI film, As a result, the interface between the positive and negative electrodes is continuously destroyed, and the transition metals in the electrodes are continuously dissolved, which eventually leads to problems such as increased gas production, degradation of cycle performance and storage performance.
  • the conventional technical means is to add water or acid removal additives to the electrolyte to inhibit the damage of acidic substances to battery performance.
  • patent documents CN105006594B and CN105633467B report the use of additives containing P or N such as tris(trimethylsilane) phosphite, N,N-dimethylpropionamide, N-methyl-2-pyrrolidone and N-substituted pyrrolidone - Boron trifluoride coordination compounds, etc.
  • Adding a small amount of such additives to the electrolyte presents a weaker Lewis basicity, which can form a six-ligand complex with PF 5 , reduce the Lewis acidity and reactivity of PF 5 , and inhibit the trace amount of PF 5 and the electrolyte. Chromaticity increase caused by impurity reaction, etc.
  • the method of adding cyclic acid anhydride compounds in the electrolytic solution reported by the patent document CN110970621B and the method of adding thiocyanate and isothiocyanate additives in the electrolytic solution reported by the patent document CN1194439C can also reduce the acidity.
  • the present application was made in view of the above-mentioned problems, and its object is to provide a secondary battery that can control the acid content in the battery system at a low level for a long time due to the inclusion of a specific separator, thereby reducing The side reactions in the battery and the consumption of active lithium can significantly improve the cycle performance and storage performance of the battery, especially the high-temperature cycle performance and high-temperature storage performance. Further, the purpose of the present application is to provide a battery module, a battery pack and an electrical device including the secondary battery.
  • the first aspect of the present application provides a secondary battery, which includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet,
  • the isolation film includes a base material and a layer of inorganic particles and/or organic particles disposed on at least one surface of the base material, and the isolation film also includes an acid scavenging additive located on the Between the inorganic particles and/or organic particles of the inorganic particle and/or organic particle layer or between the substrate and the inorganic particle and/or organic particle layer in the form of a separate layer, relative to the electrolyte
  • the mass of the acid-scavenging additive is less than 1% by mass at 25° C. in the electrolyte solution.
  • the acid removal additive includes at least one selected from pyridine compounds and phosphine compounds,
  • the pyridine compound is at least one selected from the compounds represented by chemical formula I, chemical formula II and chemical formula III:
  • the phosphine compound is at least one selected from the compounds shown in chemical formula IV:
  • R 1 to R 13 and R 15 to R 17 are each independently selected from the following: an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, Aryl groups with 6 to 26 carbon atoms, aryloxy groups with 6 to 26 carbon atoms and groups formed by substituting them with F, Cl, Br, sulfonic acid groups or sulfonyl groups, H, F, Cl and Br;
  • R 14 is one selected from the following: an alkylene group with 1 to 20 carbon atoms, an alkenylene group with 2 to 20 carbon atoms, an arylene group with 7 to 26 carbon atoms, and a carbon number of Aryloxy groups of 7 to 26 and groups formed by substituting them with F, Cl, Br, sulfonic acid group or sulfonyl group, n is an integer greater than or equal to 2.
  • the pyridine compound comprises isonicotinate, 2-hydroxypyridine-4-carboxylate, 2,2'-bipyridine-4,4'-dicarboxylate and poly( 4-vinylpyridine) at least one.
  • the isonicotinate includes lithium isonicotinate, sodium isonicotinate, potassium isonicotinate, aluminum isonicotinate, magnesium isonicotinate, calcium isonicotinate, iron isonicotinate, At least one of cobalt isonicotinate, nickel isonicotinate, and manganese isonicotinate;
  • the 2-hydroxypyridine-4-carboxylate comprises lithium 2-hydroxypyridine-4-carboxylate, sodium 2-hydroxypyridine-4-carboxylate, potassium 2-hydroxypyridine-4-carboxylate, 2- Aluminum Hydroxypyridine-4-carboxylate, Magnesium 2-Hydroxypyridine-4-carboxylate, Calcium 2-Hydroxypyridine-4-carboxylate, Iron 2-Hydroxypyridine-4-carboxylate, 2-Hydroxypyridine-4-carboxylate At least one of cobaltate, nickel 2-hydroxypyridine-4-carboxylate, manganese 2-hydroxypyridine-4-carboxylate; and
  • the 2,2'-bipyridine-4,4'-dicarboxylate includes 2,2'-bipyridine-4,4'-sodium dicarboxylate, 2,2'-bipyridine-4,4' -Potassium dicarboxylate, 2,2'-bipyridine-4,4'-aluminum dicarboxylate, 2,2'-bipyridine-4,4'-magnesium dicarboxylate, 2,2'-bipyridine-4,4 '-Calcium dicarboxylate, 2,2'-bipyridine-4,4'-iron dicarboxylate, 2,2'-bipyridine-4,4'-cobalt dicarboxylate, 2,2'-bipyridine-4, At least one of nickel 4'-dicarboxylate and manganese 2,2'-bipyridyl-4,4'-dicarboxylate.
  • the phosphine compounds include diethylphenylphosphine, trihexylphosphine, tributylphosphine, 1,6-bis(diphenylphosphino)hexane, tri(o-methoxy phenyl)phosphine, tri-n-octylphosphine, diphenylcyclohexylphosphine, diphenyl-2-pyridinephosphine, 2-(dicyclohexylphosphino)biphenyl, 2-(di-tert-butylphosphine)biphenyl At least one of benzene, diphenylethoxyphosphine, tris(2-furyl)phosphine, tricyclopentylphosphine, and diethylphenylphosphine.
  • the loading amount of the acid-scavenging additive on the separator is 0.01 g/m 2 to 20 g/m 2 , optionally 0.1 g/m 2 to 5 g/m 2 .
  • the thickness of the inorganic particle and/or organic particle layer is 0.1 ⁇ m ⁇ 10 ⁇ m, optionally 0.5 ⁇ m ⁇ 5 ⁇ m.
  • the inorganic particles include at least one selected from the group consisting of silicon oxide, aluminum oxide, boehmite, magnesium oxide, titanium dioxide, zinc oxide, and aluminum magnesium oxide; the organic particles include at least one selected from the group consisting of At least one selected from the group consisting of polyethylene oxide particles, polyvinylidene chloride particles, polyacrylonitrile particles, polyvinylidene fluoride particles, polymethyl methacrylate particles, and polyvinylidene fluoride-hexafluoropropylene copolymer particles kind.
  • the electrolyte includes a solvent and an electrolyte salt.
  • the solvent includes a solvent selected from carbonate solvents, sulfone solvents, ether solvents, sulfonate solvents, sulfate ester solvents, and at least one of sulfite-based solvents; and the electrolyte salt includes a lithium salt or a sodium salt.
  • the substrate includes at least one selected from polyethylene, polypropylene, cellulose, and polyimide.
  • a second aspect of the present application provides a battery module including the secondary battery provided in the first aspect of the present application.
  • a third aspect of the present application provides a battery pack, which includes the battery module provided in the second aspect of the present application.
  • the fourth aspect of the present application provides an electric device, which includes at least one of the secondary batteries selected from the first aspect of the present application, the battery module of the second aspect of the present application, or the battery pack of the third aspect of the present application A sort of.
  • the present application provides a secondary battery, wherein an acid-scavenging additive with low solubility in the electrolyte is introduced on the separator and the acid-scavenging additive is arranged on the inorganic particles and/or organic particle layers of the inorganic particles and/or or between the organic particles or the acid-scavenging additive is arranged in a separate layer between the base material and the inorganic particles and/or organic particle layers, the acid content in the battery system can be controlled at a relatively low level for a long time. Low level, thereby reducing the side reactions in the battery and the consumption of active lithium, thereby significantly improving the cycle performance and storage performance of the battery, especially the high-temperature cycle performance and high-temperature storage performance.
  • the battery module, battery pack and electric device of the present application include the secondary battery provided by the present application, and thus have at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of a secondary battery according to one embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • ranges disclosed herein are defined in terms of lower and upper limits, and a given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range "a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c) , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b) and so on.
  • the first embodiment of the present application can provide a secondary battery, which includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet, wherein the The isolation film includes a substrate and a layer of inorganic particles and/or organic particles disposed on at least one surface of the substrate, and the isolation film also includes an acid-scavenging additive located on the inorganic particles and Between the inorganic particles and/or organic particles of the /or organic particle layer or between the substrate and the inorganic particle and/or organic particle layer in the form of a separate layer, relative to the quality of the electrolyte, The maximum dissolved amount of the acid-scavenging additive in the electrolyte solution at 25° C.
  • the maximum dissolved amount of the acid-scavenging additive in the electrolyte at 25°C refers to the mass ratio of the acid-scavenging additive dissolved in the electrolyte at 25°C relative to the sum of the acid-scavenging additive and the electrolyte .
  • inorganic particles and/or organic particles means inorganic particles alone, organic particles alone or a mixture of both.
  • inorganic particle and/or organic particle layer refers to a layer of inorganic particles alone, a layer of organic particles alone, or a layer composed of a mixture of both. Specific examples will be described in detail in the Examples section below.
  • the acid scavenging additive is provided on the separator. During the charging and discharging process, the acidic substance in the electrolyte reacts with the acid-scavenging additive on the separator or forms a complex, so that the acid content in the battery system can be controlled at a low level.
  • the acid-scavenging additive is arranged between the inorganic particles and/or organic particles of the inorganic particle and/or organic particle layer or is arranged between the substrate and the inorganic particles and/or organic particles in the form of a separate layer.
  • the acid-scavenging additive is insoluble or slightly soluble in the electrolyte. Therefore, the acid-scavenging additive cannot be in direct contact with the positive and negative electrodes, so that little electrochemical redox reaction occurs between them. This ensures that the acid scavenging additive is present in the battery system throughout the life of the battery.
  • the reaction or compounding of the above-mentioned acid-scavenging additives with acidic substances has a larger size, so it is difficult to diffuse into the electrolyte through the inorganic particle and/or organic particle layer.
  • the acid content in the battery system can be controlled at a low level for a long time, thereby reducing the side reactions in the battery and the consumption of active lithium, thereby significantly improving the cycle performance and storage performance of the battery, especially the high-temperature cycle performance and High temperature storage performance.
  • the acid removal additive may include at least one selected from pyridine compounds and phosphine compounds,
  • the pyridine compound is at least one selected from the compounds represented by chemical formula I, chemical formula II and chemical formula III:
  • the phosphine compound can be at least one selected from the compounds shown in chemical formula IV:
  • R 1 to R 13 and R 15 to R 17 are each independently selected from the following: an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, Aryl groups with 6 to 26 carbon atoms, aryloxy groups with 6 to 26 carbon atoms and groups formed by substituting them with F, Cl, Br, sulfonic acid groups or sulfonyl groups, H, F, Cl and Br;
  • R 14 is one selected from the following: an alkylene group with 1 to 20 carbon atoms, an alkenylene group with 2 to 20 carbon atoms, an arylene group with 7 to 26 carbon atoms, and a carbon number of Aryloxy groups of 7 to 26 and groups formed by substituting them with F, Cl, Br, sulfonic acid group or sulfonyl group, n is an integer greater than or equal to 2.
  • the N atoms on the above-mentioned pyridine compounds and the P atoms on the phosphine compounds have lone electron pairs, so these compounds have Lewis basicity, and can react with acidic substances to remove them, or form complexes with acidic substances to fix acidic substances in in the isolation film.
  • the content of acidic substances in the electrolyte can be reduced, so that the acidic substances in the battery system cannot react at the interface between the positive and negative electrodes, thereby reducing the side reactions in the battery and the consumption of active lithium for a long time.
  • the cycle performance and storage performance of the battery especially the high-temperature cycle performance and high-temperature storage performance, can be significantly improved.
  • the pyridine compound may include isonicotinate, 2-hydroxypyridine-4- At least one of carboxylate, 2,2'-bipyridine-4,4'-dicarboxylate and poly(4-vinylpyridine).
  • the weight-average molecular weight of poly(4-vinylpyridine) is not particularly limited, as long as poly(4-vinylpyridine) is slightly soluble or insoluble in the electrolyte and can achieve the effect of removing acid, for example, it can be 40,000 to 900000.
  • the poly(4-vinylpyridine) may have a weight average molecular weight of 50,000 to 850,000, 60,000 to 800,000, 70,000 to 750,000, 75,000 to 700,000, 80,000 to 650,000, 100,000 to 550,000, 150,000 to 450,000, 200,000 to 4,000 00, 250000 to 350000, 300000 to 350000 and 320000 to 550000.
  • the cation of the pyridine-containing carboxylate is not particularly limited, and cations commonly used in electrolytes can be used.
  • the isonicotinate may include lithium isonicotinate, sodium isonicotinate, potassium isonicotinate, isonicotinic acid At least one of aluminum oxide, magnesium isonicotinate, calcium isonicotinate, iron isonicotinate, cobalt isonicotinate, nickel isonicotinate, manganese isonicotinate;
  • the 2-hydroxypyridine-4-carboxylate Can include lithium 2-hydroxypyridine-4-carboxylate, sodium 2-hydroxypyridine-4-carboxylate, potassium 2-hydroxypyridine-4-carboxylate, aluminum 2-hydroxypyridine-4-carboxylate, 2- Magnesium hydroxypyridine-4-carboxylate, calcium 2-hydroxypyridine-4-carboxylate, iron 2-hydroxypyridine-4-carboxycar
  • the phosphine compound may include diethylphenylphosphine, trihexylphosphine, tri Butylphosphine, 1,6-bis(diphenylphosphino)hexane, tris(o-methoxyphenyl)phosphine, tri-n-octylphosphine, diphenylcyclohexylphosphine, diphenyl-2-pyridine Phosphine, 2-(dicyclohexylphosphino)biphenyl, 2-(di-tert-butylphosphine)biphenyl, diphenylethoxyphosphine, tri(2-furyl)phosphine, tricyclopentylphosphine, di At least one of ethylphenylphosphine.
  • the loading amount of the acid-scavenging additive on the isolation membrane may be 0.01 g/m 2 to 20 g/m 2 , optionally 0.1 g/m 2 to 5 g/m 2 .
  • the loading of the acid-scavenging additive on the isolation membrane can also be 0.05g/m 2 -20g/m 2 , 0.3g/m 2 -19g/m 2 , 0.5g/m 2 -18g/m 2 , 0.7g/m 2 ⁇ 17g/m 2 , 0.8g /m 2 ⁇ 16g/m 2 , 0.9g/m 2 ⁇ 15g/m 2 , 1.0g/m 2 ⁇ 14g/m 2 , 1.5g/m 2 ⁇ 12g/m 2 , 1.8g/m 2 ⁇ 11g/m 2 , 2.0g/m 2 ⁇ 10g/m 2 , 2.5g/m 2 ⁇ 8g/m 2 , 2.9g/m 2 ⁇ 7g/m 2 , 3.0
  • the amount of the acid-scavenging additive loaded on the separator can be adjusted according to actual conditions (for example, according to the battery system and the acid-scavenging ability of the selected acid-scavenging additive).
  • the load of the acid-scavenging additive on the separator can be set to be greater than or equal to 0.01 g/m 2 , thereby effectively reducing the content of acidic substances in the battery system.
  • the load of the acid-scavenging additive on the separator can be set to be less than or equal to 20 g/m 2 , so that it can be used for a long-term, Fully guarantee the deacidification effect.
  • the thickness of the inorganic particle and/or organic particle layer may be 0.1 ⁇ m ⁇ 10 ⁇ m, optionally 0.5 ⁇ m ⁇ 5 ⁇ m.
  • the thickness of the inorganic particle and/or organic particle layer may be 0.2 ⁇ m to 9 ⁇ m, 0.3 ⁇ m to 8.5 ⁇ m, 0.4 ⁇ m to 8 ⁇ m, 0.5 ⁇ m to 7.5 ⁇ m, 0.6 ⁇ m to 7.0 ⁇ m, 0.7 ⁇ m to 6.5 ⁇ m, 0.8 ⁇ m to 6.0 ⁇ m, 0.9 ⁇ m to 5.5 ⁇ m, 1.0 ⁇ m to 5.0 ⁇ m, 1.5 ⁇ m to 4.5 ⁇ m, 2.0 ⁇ m to 4.0 ⁇ m, 2.5 ⁇ m to 3.8 ⁇ m, 2.7 ⁇ m to 3.4 ⁇ m and 2.8 ⁇ m to 3.9 ⁇ m.
  • the thickness of the inorganic particle and/or organic particle layer can be adjusted according to the actual situation (for example, according to the battery system, the acid removal ability of the selected acid removal additive, the size of the acid removal additive, etc.).
  • the thickness of the inorganic particle and/or organic particle layer can be set to be greater than or equal to 0.5 ⁇ m, thereby effectively isolating the contact between the acid-scavenging additive and the interface of the positive and negative electrodes.
  • the thickness of the inorganic particle and/or organic particle layer can be set to be less than or equal to 10 ⁇ m, so that the air permeability of the isolation film can be not significantly deteriorated (the pores of the isolation film will not be seriously blocked) and the air permeability of the isolation film can not be significantly increased.
  • the acid removal effect is guaranteed and the occurrence of side reactions inside the battery is reduced.
  • the inorganic particles there are no particular limitations on the inorganic particles as long as they have electronic insulation and appropriate mechanical strength. Thus, it can be ensured that the positive and negative active materials are not in contact with the acid-scavenging additive on the isolation membrane, nor conduct electrons to the acid-scavenging additive, so that the acid-scavenging additive cannot undergo redox reactions and ensure the stability of the acid-scavenging additive on the isolation membrane sex.
  • the inorganic particles may include: , zinc oxide, aluminum magnesium oxide at least one of the group consisting of.
  • the organic particles include particles selected from polyethylene oxide particles, polyvinylidene chloride particles, polyacrylonitrile particles, polyvinylidene fluoride At least one selected from the group consisting of ethylene particles, polymethyl methacrylate particles, and polyvinylidene fluoride-hexafluoropropylene copolymer particles.
  • the electrolyte may be commonly used in the art.
  • the electrolytic solution may include a solvent and an electrolyte salt.
  • the solvent may include solvents commonly used in the art, such as solvents selected from carbonate solvents, sulfone solvents, ether solvents, sulfonate solvents, sulfate ester solvents and sulfite solvents. at least one.
  • the electrolyte salt may include lithium salt or sodium salt.
  • the substrate may be a substrate commonly used in the art as a separator substrate.
  • the base material may include at least one selected from polyethylene, polypropylene, cellulose, and polyimide.
  • the thickness of the substrate may be 1-20 ⁇ m.
  • the thickness of the substrate may be 2-15 ⁇ m, 2-10 ⁇ m, 2.5-9 ⁇ m, 3-8 ⁇ m, 3.5-8 ⁇ m, 4-7.5 ⁇ m, 4.5-6 ⁇ m and 5-6.5 ⁇ m.
  • a second aspect of the present application provides a battery module including the secondary battery provided in the first aspect of the present application.
  • a third aspect of the present application provides a battery pack, which includes the battery module provided in the second aspect of the present application.
  • the fourth aspect of the present application provides an electric device, which includes at least one of the secondary batteries selected from the first aspect of the present application, the battery module of the second aspect of the present application, or the battery pack of the third aspect of the present application A sort of.
  • the above-mentioned battery module, battery pack and electrical device include the secondary battery of the present application, so the cycle performance and storage performance of the battery, especially the high-temperature cycle performance and high-temperature storage performance, can be significantly improved.
  • the secondary battery of the present application may include a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet.
  • the secondary battery, battery module, battery pack and electric device of the present application will be described in detail below with reference to the accompanying drawings.
  • the negative electrode sheet may include a negative electrode collector and a negative electrode film disposed on at least one surface of the negative electrode collector.
  • the negative electrode membrane may include negative electrode active materials and optional binders, conductive agents and other additives.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode membrane is disposed on either or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector may use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate.
  • Composite current collectors can be formed by metal materials (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) Formed on substrates such as polyethylene formate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode active material may include a material selected from natural graphite, modified graphite, artificial graphite, graphene, carbon nanotubes, carbon nanofibers, porous carbon, tin, antimony, germanium , lead, ferric oxide, vanadium pentoxide, tin dioxide, titanium dioxide, molybdenum trioxide, elemental phosphorus, sodium titanate and sodium terephthalate.
  • the negative electrode membrane may also optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode membrane may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon nanotubes, carbon nanorods, graphene and carbon nanofibers.
  • the negative electrode membrane may also optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form negative electrode slurry; the negative electrode slurry can be coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • the negative electrode sheet can be manufactured by casting the negative electrode slurry used to form the negative electrode film on a separate carrier, and then the film obtained by peeling off from the carrier laminated on the negative electrode collector.
  • the positive electrode piece includes a positive electrode current collector and a positive electrode membrane disposed on at least one surface of the positive electrode current collector and including a positive electrode active material.
  • the positive current collector has two opposing surfaces in its own thickness direction, and the positive electrode membrane is disposed on any one or both of the two opposing surfaces of the positive current collector.
  • the positive current collector can be made of a material with good electrical conductivity and mechanical strength.
  • the positive current collector may be aluminum foil.
  • the present application does not specifically limit the specific type of positive electrode active material, and materials known in the art that can be used for the positive electrode of secondary batteries can be used, and those skilled in the art can choose according to actual needs.
  • the secondary battery may be a lithium ion secondary battery.
  • the positive electrode active material can be selected from lithium transition metal oxides and modified materials thereof.
  • the modified material may be doping modification and/or coating modification of the lithium transition metal oxide.
  • the lithium transition metal oxide can be selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and olivine structure containing One or more of lithium phosphates.
  • the positive electrode active material of the secondary battery may be selected from LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), LiNi 0.85 Co 0.15 Al 0.05 O 2 , LiFePO 4 (LFP) and LiMnPO 4 one or several.
  • the positive electrode may contain at least one positive active material selected from the group consisting of layered transition metal oxides, polyanionic compounds, Prussian blue compounds, sulfides, Nitrides, carbides, titanates.
  • the positive electrode active material includes, but is not limited to, selected from NaCrO 2 , Na 2 Fe 2 (SO 4 ) 3 , molybdenum disulfide, tungsten disulfide, vanadium disulfide, titanium disulfide, hexagonal boron nitride, carbon Doped with hexagonal boron nitride, titanium carbide, tantalum carbide, molybdenum carbide, silicon carbide, Na 2 Ti 3 O 7 , Na 2 Ti 6 O 13 , Na 4 Ti 5 O 12 , Li 4 Ti 5 O 12 , NaTi 2 ( At least one selected from the group consisting of PO 4 ) 3 .
  • a binder is optionally included in the positive electrode membrane.
  • the type of binder is not specifically limited, and those skilled in the art can select according to actual needs.
  • the binder used for the positive electrode membrane may include one or more of polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).
  • a conductive agent is optionally included in the positive electrode film.
  • the type of conductive agent is not specifically limited, and those skilled in the art can select according to actual needs.
  • the conductive agent used for the positive electrode membrane may include one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • the electrolyte may be liquid or gel.
  • the electrolytic solution of the embodiment of the present application may contain additives.
  • the additives may include additives commonly used in this field.
  • the additives may include, for example, halogenated alkylene carbonate compounds (such as difluoroethylene carbonate), pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, (glyme) Ethers, hexamethylphosphoric triamide, nitrobenzene derivatives, sulfur, quinoneimine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts , pyrrole, 2-methoxyethanol or aluminum trichloride.
  • the additive may be included in an amount of 0.1 mass % to 5 mass % or the amount of the additive may be adjusted by those skilled in the art according to actual needs.
  • the electrolytic solution may contain electrolyte salts and solvents.
  • the electrolyte salt may comprise a compound selected from LiPF 6 , LiBF 4 , LiN(SO 2 F) 2 (LiFSI), LiN(CF 3 SO 2 ) 2 (LiTFSI), At least one of LiClO 4 , LiAsF 6 , LiB(C 2 O 4 ) 2 (LiBOB), and LiBF 2 C 2 O 4 (LiDFOB).
  • the electrolyte salt may include at least one selected from NaPF 6 , NaClO 4 , NaBCl 4 , NaSO 3 CF 3 , and Na(CH 3 )C 6 H 4 SO 3 .
  • the electrolyte solution may also contain other solvents commonly used in the art such as selected from 1,4-butyrolactone, sulfolane, At least one of dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the separator of the present application employs the above-mentioned separator.
  • the separator of the present application can be used in combination with other separators commonly used in the art as needed.
  • the secondary battery may include an outer package for encapsulating the positive electrode tab, the negative electrode tab, and the electrolyte.
  • the positive pole piece, the negative pole piece and the separator can be laminated or wound to form a laminated structure battery or a wound structure battery, and the battery is packaged in an outer package; the electrolyte is infiltrated in the battery.
  • the number of batteries in the secondary battery can be one or several, and can be adjusted according to requirements.
  • the outer package of the secondary battery may be a soft bag, such as a pouch-type soft bag.
  • the material of the soft bag can be plastic, such as one or more of polypropylene PP, polybutylene terephthalate PBT, polybutylene succinate PBS, etc. can be included.
  • the outer package of the secondary battery may also be a hard case, such as an aluminum case.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • FIG. 1 shows a secondary battery 5 with a square structure as an example.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 2 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may further include a case having an accommodation space in which a plurality of secondary batteries 5 are accommodated.
  • the battery modules provided in the second aspect of the present application can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • a fourth aspect of the present application further provides an electric device, the electric device includes the secondary battery according to the first aspect of the present application, and the secondary battery provides power for the electric device.
  • the electric device can be, but not limited to, mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the electric device can select a secondary battery, a battery module or a battery pack according to its usage requirements.
  • FIG. 5 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • the electric device may be a mobile phone, a tablet computer, a notebook computer, and the like.
  • the electrical device is usually required to be light and thin, and a secondary battery can be used as a power source.
  • the lithium/sodium ion batteries of Examples 1-48 and Comparative Examples 1-5 were all prepared according to the following methods, and the specific composition of the separator is shown in Table 1 below.
  • the positive electrode active material lithium manganese oxide, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) in the solvent N-methylpyrrolidone (NMP) at a mass ratio of 94:3:3, and mix well Finally, the positive electrode slurry is obtained; after that, the positive electrode slurry is evenly coated on the aluminum foil of the positive electrode current collector, and then dried, cold pressed, and cut to obtain the positive electrode sheet.
  • NMP N-methylpyrrolidone
  • Negative active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener carboxymethylcellulose sodium (CMC-Na) are dissolved in the solvent according to the mass ratio of 95:2:2:1 deionized water. After being uniformly mixed with solvent deionized water, the negative electrode slurry is prepared; then the negative electrode slurry is uniformly coated on the copper foil of the negative electrode current collector one or more times, and then dried, cold pressed, and cut to obtain the negative electrode sheet .
  • the organic solvent ethylene carbonate/ethyl methyl carbonate (EC/EMC) was mixed uniformly according to the volume ratio of 3/7 to obtain a mixed solvent .
  • EC/EMC organic solvent ethylene carbonate/ethyl methyl carbonate
  • PS 1,3-propane sultone
  • DTD ethylene sulfate
  • VC Vinylene carbonate
  • the positive electrode active material sodium vanadium phosphate, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) in the solvent N-methylpyrrolidone (NMP) at a mass ratio of 80:15:3, and mix well Finally, the positive electrode slurry is obtained; after that, the positive electrode slurry is evenly coated on the aluminum foil of the positive electrode current collector, and then dried, cold pressed, and cut to obtain the positive electrode sheet.
  • NMP N-methylpyrrolidone
  • the active material hard carbon, the conductive agent acetylene black, the binder styrene-butadiene rubber, and the thickener carboxymethylcellulose sodium (CMC-Na) were dissolved in the solvent deionized water at a mass ratio of 91.6:1.6:4.8:2.
  • Negative electrode slurry is prepared after being uniformly mixed with solvent deionized water; then the negative electrode slurry is uniformly coated on the negative electrode current collector aluminum foil one or more times, and then dried, cold pressed, and cut to obtain the negative electrode sheet.
  • the organic solvent ethylene carbonate/ethylmethyl carbonate (EC/EMC) was uniformly mixed at a volume ratio of 3/7. Relative to the mass of the mixed solvent, 13.8% by mass of NaPF 6 lithium salt and 1% by mass of VC as an additive were added, and the corresponding electrolyte solution was obtained after uniform stirring.
  • Layered coating first dissolve or disperse the acid scavenging additive in deionized water, then apply the dissolved or dispersed acid scavenging additive on the substrate polyethylene by gravure method to obtain the acid scavenging additive layer, which can be used multiple times Apply to achieve desired loading. Then disperse the non-conductive inorganic particle raw material and/or organic particle raw material and water-based polyacrylate binder in deionized water at a mass ratio of 99:1 to obtain an inorganic and/or organic slurry, and then the inorganic and/or organic slurry coating on top of the acid scavenging additive layer.
  • the desired thickness of the inorganic particle and/or organic particle layer can be obtained by adjusting the coating quality of the inorganic and/or organic slurry.
  • Coating isolation film disperse acid-removing additives, non-conductive inorganic particle raw materials and/or organic particle raw materials and water-based polyacrylate binder in deionized water at a mass ratio of 10:89:1 to obtain inorganic and/or organic pulp material, and then coat the inorganic and/or organic slurry on the base material polyethylene, and the desired thickness of the inorganic particle and/or organic particle layer can be obtained by adjusting the coating quality of the inorganic and/or organic slurry.
  • the hybrid coating separator of Example 35 disperse the acid-scavenging additive, non-conductive inorganic powder and water-based polyacrylate binder in deionized water at a mass ratio of 30:69:1 to obtain an inorganic slurry, and then the inorganic The slurry is coated on the substrate polyethylene, and the required thickness of the inorganic particle layer can be obtained by adjusting the coating quality of the inorganic slurry.
  • the hybrid coating separator of Example 36 disperse the acid-scavenging additive, non-conductive inorganic powder and water-based polyacrylate binder in deionized water at a mass ratio of 40:59:1 to obtain an inorganic slurry, and then mix the inorganic The slurry is coated on the substrate polyethylene, and the required thickness of the inorganic particle layer can be obtained by adjusting the coating quality of the inorganic slurry.
  • the maximum dissolved amount of each acid-scavenging additive in the electrolyte at 25°C is measured by measuring the maximum dissolved amount of each acid-scavenging additive in the corresponding electrolyte at 25°C and dividing the mass by The total mass of dissolved acid-scavenging additive and electrolyte is obtained.
  • Air permeability refers to the time it takes for a certain volume of air to pass through a unit area of paper and cardboard under unit pressure under specified conditions.
  • the air permeability test of the isolation film is tested with reference to GB/T458-2008, the air column volume is 100cc, and the test area is 1 square inch.
  • Lithium-ion battery at 25°C, charge the lithium-ion battery with a constant current of 1C to 4.3V, then charge it with a constant voltage of 4.3V until the current is less than 0.05C, and then discharge it at 1C for 30min, that is, adjust the battery power to 50% SOC. Then touch the positive and negative test leads of the TH2523A AC internal resistance tester to the positive and negative electrodes of the battery respectively, and read the internal resistance value of the battery through the internal resistance tester.
  • Sodium-ion battery At 25°C, charge the sodium-ion battery with a constant current of 1C to 4.2V, then charge it with a constant voltage of 4.2V until the current is less than 0.05C, and then discharge it at 1C for 30 minutes, that is, adjust the battery power to 50% SOC. Then touch the positive and negative test leads of the TH2523A AC internal resistance tester to the positive and negative electrodes of the battery respectively, and read the internal resistance value of the battery through the internal resistance tester.
  • Lithium-ion battery At 45°C, charge the lithium-ion battery with a constant current of 1C to 4.3V, then charge it with a constant voltage of 4.3V until the current is less than 0.05C, and then discharge the lithium-ion battery with a constant current of 1C to 3.0V. For a charging and discharging process. Charge and discharge are repeated in this way, and the capacity retention rate of the lithium-ion battery after 800 cycles is calculated.
  • the capacity retention (%) of the lithium-ion battery after 800 cycles at 45°C (discharge capacity of the 800th cycle/discharge capacity of the first cycle) ⁇ 100%.
  • Sodium-ion battery At 45°C, charge the sodium-ion battery with a constant current of 1C to 4.2V, then charge it with a constant voltage of 4.2V until the current is less than 0.05C, and then discharge the sodium-ion battery with a constant current of 1C to 2.0V. For a charging and discharging process. Charge and discharge are repeated in this way, and the capacity retention rate of the sodium-ion battery after 800 cycles is calculated.
  • the capacity retention rate (%) of the sodium-ion battery after 800 cycles at 45°C (discharge capacity of the 800th cycle/discharge capacity of the first cycle) ⁇ 100%.
  • Lithium-ion battery at 25°C, charge it with a constant current of 1C to a voltage of 4.3V, and then charge it with a constant voltage of 4.3V to a current of 0.05C. At this time, measure the volume of the lithium-ion battery and record it as V21; then fully charge it The lithium-ion battery was placed in a 60°C incubator, stored for 50 days, and the volume was measured by the drainage method and recorded as V31.
  • the volume expansion rate (%) of the lithium-ion battery after storage at 60°C for 50 days (V31-V21)/V21 ⁇ 100%.
  • Sodium-ion battery at 25°C, charge with a constant current of 1C to a voltage of 4.2V, and then charge with a constant voltage of 4.2V to a current of 0.05C. At this time, measure the volume of the sodium-ion battery and record it as V22; then fully charge The sodium-ion battery was placed in a 60°C incubator, stored for 50 days, and the volume was measured by the drainage method and recorded as V32.
  • the volume expansion rate (%) of the sodium-ion battery after storage at 60°C for 50 days (V32-V22)/V22 ⁇ 100%.
  • Table 2 below shows the test data of Comparative Examples 1, 3 and 4 and Example 4.
  • the lithium 2,2'-bipyridyl-4,4'-dicarboxylate in Example 4 can significantly improve the cycle performance of the battery, which is mainly due to the following reasons.
  • the acidic substance in the electrolyte reacts with the acid removal additive 2,2'-bipyridyl-4,4'-dicarboxylate lithium on the separator, so that the acid content in the battery system can be controlled at a relatively low level. low level.
  • the acid-scavenging additive lithium 2,2'-bipyridyl-4,4'-dicarboxylate is provided in a separate layer between the substrate and the layer of inorganic particles and/or organic particles, and The solubility in the electrolyte is low. Therefore, the acid-scavenging additive lithium 2,2'-bipyridyl-4,4'-dicarboxylate cannot be in direct contact with the positive and negative electrodes, so that there is almost no electrochemical redox reaction between them. This ensures that the acid scavenging additive lithium 2,2'-bipyridyl-4,4'-dicarboxylate is present in the battery system throughout the life of the battery. As a result, the high-temperature cycle performance and high-temperature storage performance of the battery can be significantly improved.
  • Table 3 below shows the test data of Comparative Example 1 and Examples 1-18.
  • Table 4 below shows the test data for Comparative Examples 1, 2 and 5 and Example 11 and Examples 19-47.
  • the conventional batteries such as the batteries of Comparative Example 1 and Comparative Example 2 have relatively large volume expansion ratios when stored at 60°C for 50 days.
  • the volume expansion rate of the battery of the embodiment of the present application can reach 5% (actually, considering measurement errors and the like, the volume expansion rate of 5% is basically a measurable lower limit).
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

本申请提供一种二次电池及包含其的用电装置，所述二次电池包括正极极片、负极极片以及设置在所述正极极片与所述负极极片之间的隔离膜和电解液，其中所述隔离膜包括基材和设置于所述基材的至少一个表面之上的无机颗粒和/或有机颗粒层，并且所述隔离膜还包括除酸添加剂，所述除酸添加剂位于所述无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者以单独的层的形式位于所述基材与所述无机颗粒和/或有机颗粒层之间，相对于所述电解液的质量，所述除酸添加剂在25℃下在所述电解液中的最大溶解量为小于1质量％。

Description

二次电池及包含其的用电装置 技术领域
本申请涉及二次电池技术领域，尤其涉及一种二次电池及包含其的用电装置。
背景技术
二次电池因具有能量密度高、无污染、使用寿命长等突出特点而被广泛应用。然而，在二次电池中，电解液对水分敏感，因此容易生成酸性物质，从而破坏电池性能。具体地，酸性物质不耐电化学氧化和还原，因此会消耗电池中的活性锂、降低库仑效率、恶化电池内阻、降低电池容量和增加产气量等；并且酸性物质还会刻蚀SEI膜，导致正负极界面被不断破坏、电极中的过渡金属被持续溶出，最终导致产气量增加、循环性能和存储性能劣化等问题。
目前，常规技术手段是在电解液中添加除水或除酸的添加剂以抑制酸性物质对电池性能的破坏。例如，专利文献CN105006594B和CN105633467B报道了使用含有P或N的添加剂如三(三甲基硅烷)亚磷酸酯、N,N-二甲基丙酰胺、N-甲基-2-吡咯烷酮和N取代吡咯烷酮-三氟化硼配位化合物等。这类添加剂少量添加到电解液中呈现较弱的路易斯碱性，从而能与PF 5形成六配体的配合物，降低PF 5的路易斯酸性和反应活性，以抑制PF 5与电解液中的微量杂质反应引起的色度上升等。此外，专利文献CN110970621B报道的在电解液中添加环状酸酐类化合物的方法和专利文献CN1194439C报道的在电解液中添加硫氰酸酯、异硫氰酸酯类添加剂的方法也可以降低电解液的酸度。但是，这些添加剂与酸性物质和水反应生成的产物仍具有电化学活性，因此会在正负极处发生电化学副反应，并且最终导致电池性能劣化如增大电池膨胀、降低库仑效率等。此外，这些添加剂本身也会在正负极表面处持续发生反应，在电池的初始循环中耗尽而不能长期存在于电池中。因此，这些添加剂不能实现在电池的长期循环中除酸的效果。CN102709591B报道了一种疏水隔离膜，其中通过在基材上涂敷具有疏水特性的长链醇类、酮类、醛类、酯类、醚类和烷烃类聚合物，能够降低因电池制造过程引入的水分。但是，这种方法不能改变制备完成的电池中的酸性物质和水的含量，并且对溶剂氧化过程中形成的酸性物质也没有清除作用。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种二次电池，所述二次电池因包含特定的隔离膜而可以长期将电池体系内的酸含量控制在较低水平，从而减少电池内的副反应和活性锂的消耗，由此显著提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能。进一步地，本申请的目的还在于提供一种包含所述二次电池的电池模块、电池包和用电装置。
为了实现上述目的，本申请的第一方面提供一种二次电池，其包括正极极片、负极极片以及设置在所述正极极片与所述负极极片之间的隔离膜和电解液，其中所述隔离膜包括基材和设置于所述基材的至少一个表面之上的无机颗粒和/或有机颗粒层，并且所述隔离膜还包括除酸添加剂，所述除酸添加剂位于所述无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者以单独的层的形式位于所述基材与所述无机颗粒和/或有机颗粒层之间，相对于所述电解液的质量，所述除酸添加剂在25℃下在所述电解液中的最大溶解量为小于1质量％。
在一些实施方式中，所述除酸添加剂包括选自吡啶类化合物和膦类化合物中的至少一种，
所述吡啶类化合物为选自化学式Ⅰ、化学式Ⅱ和化学式Ⅲ所示的化合物中的至少一种：
Figure PCTCN2021136599-appb-000001
所述膦类化合物为选自化学式Ⅳ所示的化合物中的至少一种：
Figure PCTCN2021136599-appb-000002
其中，R 1～R 13和R 15～R 17各自独立地为选自如下中的一种：碳原子数为 1～20的烷基，碳原子数为2～20的烯基，碳原子数为6～26的芳基，碳原子数为6～26的芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，H，F，Cl和Br；R 14为选自如下中的一种：碳原子数为1～20的次烷基，碳原子数为2～20的次烯基，碳原子数为7～26的次芳基，碳原子数为7～26的次芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，n为大于等于2的整数。
在一些实施方式中，所述吡啶类化合物包括选自异烟酸盐、2-羟基吡啶-4-羧酸盐、2,2'-联吡啶-4,4'-二甲酸盐和聚(4-乙烯吡啶)中的至少一种。
在一些实施方式中，所述异烟酸盐包括选自异烟酸锂、异烟酸钠、异烟酸钾、异烟酸铝、异烟酸镁、异烟酸钙、异烟酸铁、异烟酸钴、异烟酸镍、异烟酸锰中的至少一种；
所述2-羟基吡啶-4-羧酸盐包括选自2-羟基吡啶-4-羧酸锂、2-羟基吡啶-4-羧酸钠、2-羟基吡啶-4-羧酸钾、2-羟基吡啶-4-羧酸铝、2-羟基吡啶-4-羧酸镁、2-羟基吡啶-4-羧酸钙、2-羟基吡啶-4-羧酸铁、2-羟基吡啶-4-羧酸钴、2-羟基吡啶-4-羧酸镍、2-羟基吡啶-4-羧酸锰中的至少一种；并且
所述2,2'-联吡啶-4,4'-二甲酸盐包括选自2,2'-联吡啶-4,4'-二甲酸钠、2,2'-联吡啶-4,4'-二甲酸钾、2,2'-联吡啶-4,4'-二甲酸铝、2,2'-联吡啶-4,4'-二甲酸镁、2,2'-联吡啶-4,4'-二甲酸钙、2,2'-联吡啶-4,4'-二甲酸铁、2,2'-联吡啶-4,4'-二甲酸钴、2,2'-联吡啶-4,4'-二甲酸镍、2,2'-联吡啶-4,4'-二甲酸锰中的至少一种。
在一些实施方式中，所述膦类化合物包括选自二乙基苯基膦、三己基膦、三丁基膦、1,6-双(二苯基膦基)己烷、三(邻甲氧基苯基)膦、三正辛基膦、二苯基环己基膦、二苯基-2-吡啶膦、2-(二环己基膦基)联苯、2-(二叔丁基膦)联苯、二苯基乙氧基膦、三(2-呋喃基)膦、三环戊基膦、二乙基苯膦中的至少一种。
在一些实施方式中，所述除酸添加剂在所述隔离膜上的负载量为0.01g/m 2～20g/m 2，可选地为0.1g/m 2～5g/m 2。
在一些实施方式中，所述无机颗粒和/或有机颗粒层的厚度为0.1μm～10μm，可选地为0.5μm～5μm。
在一些实施方式中，所述无机颗粒包括选自由氧化硅、氧化铝、勃姆石、氧化镁、二氧化钛、氧化锌、氧化铝镁构成的组中的至少一种；所述有机颗粒包括选自由聚氧化乙烯颗粒、聚偏氯乙烯颗粒、聚丙烯腈颗粒、聚偏二氟乙烯颗粒、聚甲基丙烯酸甲酯颗粒、聚偏二氟乙烯-六氟丙烯共聚物颗粒构成的组中的至少一种。
在一些实施方式中，所述电解液包括溶剂和电解质盐，可选地，所述溶剂包括选自碳酸酯类溶剂、砜类溶剂、醚类溶剂、磺酸酯类溶剂、硫酸酯类溶剂和亚硫酸酯类溶剂中的至少一种；并且所述电解质盐包括锂盐或钠盐。
在一些实施方式中，所述基材包括选自聚乙烯、聚丙烯、纤维素和聚酰亚胺中的至少一种。
本申请的第二方面提供一种电池模块，其包括本申请的第一方面提供的二次电池。
本申请的第三方面提供一种电池包，其包括本申请的第二方面提供的电池模块。
本申请的第四方面提供一种用电装置，其包括选自本申请的第一方面的二次电池、本申请的第二方面的电池模块或本申请的第三方面的电池包中的至少一种。
有益效果
本申请提供一种二次电池，其中通过在隔离膜上引入在电解液中溶解度低的除酸添加剂并且将所述除酸添加剂设置于所述无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者将所述除酸添加剂以单独的层的形式设置 于所述基材与所述无机颗粒和/或有机颗粒层之间，可以长期将电池体系内的酸含量控制在较低水平，从而减少电池内的副反应和活性锂的消耗，由此显著提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能。
本申请的电池模块、电池包和用电装置包括本申请提供的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据本申请的教导对其做修改。
图1是本申请的一个实施方式的二次电池的示意图。
图2是图1所示的本申请的一个实施方式的二次电池的分解图。
图3是本申请的一个实施方式的电池模块的示意图。
图4是本申请的一个实施方式的电池包的示意图。
图5是图4所示的本申请的一个实施方式的电池包的分解图。
图6是本申请的一个实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5锂离子电池；51壳体；52电极组件；53顶盖组件。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的二次电池、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种或两种以上。
以下对本申请的实施方式进行详细说明。
[二次电池]
本申请的第一实施方式可以提供一种二次电池，其包括正极极片、负极极片以及设置在所述正极极片与所述负极极片之间的隔离膜和电解液，其中所述隔离膜包括基材和设置于所述基材的至少一个表面之上的无机颗粒和/或有机颗粒层，并且所述隔离膜还包括除酸添加剂，所述除酸添加剂位于所述无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者以单独的层的形式位于所述基材与所述无机颗粒和/或有机颗粒层之间，相对于所述电解液的质量，所述除酸添加剂在25℃下在所述电解液中的最大溶解量为小于1质量％。在本申请中，“除酸添加剂在25℃下在电解液中的最大溶解量”是指在25℃下溶解于电解液中的除酸添加剂相对于除酸添加剂和电解液的总和的质量比率。
在本申请中，术语“无机颗粒和/或有机颗粒”是指单独的无机颗粒、单独的有机颗粒或者两者的混合物。例如，术语“无机颗粒和/或有机颗粒层”是指单独的无机颗粒的层、单独的有机颗粒的层或者两者的混合物构成的层。具体例子将在下文的实施例部分进行详细说明。
在本申请的二次电池中，除酸添加剂被设置在隔离膜上。在充放电过程中，电解液中的酸性物质与隔离膜上的除酸添加剂反应或者形成配合物，从而可以将电池体系内的酸含量控制在较低水平。此外，在本申请中，除酸添加剂被设置在无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者以单独的层的形式被设置在基材与无机颗粒和/或有机颗粒层之间，并且在电解液中的溶解度低(即除酸添加剂在电解液中不溶或微溶)。因此，除酸添加剂无法与正极和负极直接接触，从而彼此之间几乎不发生电化学氧化还原反应。这保证除酸添加剂在电池的整个寿命周期中存在于电池体系中。另外，相比于酸性物质，上述除酸添加剂与酸性物质反应或配合后得到的产物的尺寸较大，因而不易穿过无机颗粒和/或有机颗粒层而扩散到电解液中。因此，即使在上述产物能在正负极处发生电化学反应的情况下，由于上述产物无法与正负极直接接触，所以彼此之间也几乎不发生电化学氧化还原反应。通过上述配置，可以长期将电池体系内的酸含量控制在较低水平，从而减少电池内的副反应和活性锂的消耗，由此显著提升电池的循环性能和存储性能、尤其是高温循环性能 和高温存储性能。
在一些实施方式中，所述除酸添加剂可以包括选自吡啶类化合物和膦类化合物中的至少一种，
所述吡啶类化合物为选自化学式Ⅰ、化学式Ⅱ和化学式Ⅲ所示的化合物中的至少一种：
Figure PCTCN2021136599-appb-000003
所述膦类化合物可以为选自化学式Ⅳ所示的化合物中的至少一种：
Figure PCTCN2021136599-appb-000004
其中，R 1～R 13和R 15～R 17各自独立地为选自如下中的一种：碳原子数为1～20的烷基，碳原子数为2～20的烯基，碳原子数为6～26的芳基，碳原子数为6～26的芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，H，F，Cl和Br；R 14为选自如下中的一种：碳原子数为1～20的次烷基，碳原子数为2～20的次烯基，碳原子数为7～26的次芳基，碳原子数为7～26的次芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，n为大于等于2的整数。
上述吡啶类化合物上的N原子和膦类化合物上的P原子具有孤立电子对，因而这些化合物具有路易斯碱性，能够与酸性物质反应将其除去，或者与酸性物质形成配合物将酸性物质固定在隔离膜中。由此，可以降低电解液中酸性物质的含量，使得电池体系中的酸性物质无法在正负极界面处发生反应，从而可以长期减少电池内的副反应和活性锂的消耗。由此，可以显著提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能。
在一些实施方式中，从提升电池的循环性能和存储性能、尤其是高温循环 性能和高温存储性能的观点考虑，所述吡啶类化合物可以包括选自异烟酸盐、2-羟基吡啶-4-羧酸盐、2,2'-联吡啶-4,4'-二甲酸盐和聚(4-乙烯吡啶)中的至少一种。在本申请中，聚(4-乙烯吡啶)的重均分子量没有特别限制，只要聚(4-乙烯吡啶)微溶或不溶于电解液并且能够实现除酸的效果即可，例如可以为40000至900000。可选地，聚(4-乙烯吡啶)的重均分子量可以为50000至850000，60000至800000，70000至750000，75000至700000，80000至650000，100000至550000，150000至450000，200000至400000，250000至350000，300000至350000和320000至550000。
在一些实施方式中，含吡啶的羧酸盐的阳离子没有特别限制，可以使用电解液中常用的阳离子。从提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能的观点考虑，所述异烟酸盐可以包括选自异烟酸锂、异烟酸钠、异烟酸钾、异烟酸铝、异烟酸镁、异烟酸钙、异烟酸铁、异烟酸钴、异烟酸镍、异烟酸锰中的至少一种；所述2-羟基吡啶-4-羧酸盐可以包括选自2-羟基吡啶-4-羧酸锂、2-羟基吡啶-4-羧酸钠、2-羟基吡啶-4-羧酸钾、2-羟基吡啶-4-羧酸铝、2-羟基吡啶-4-羧酸镁、2-羟基吡啶-4-羧酸钙、2-羟基吡啶-4-羧酸铁、2-羟基吡啶-4-羧酸钴、2-羟基吡啶-4-羧酸镍、2-羟基吡啶-4-羧酸锰中的至少一种；并且所述2,2'-联吡啶-4,4'-二甲酸盐可以包括选自2,2'-联吡啶-4,4'-二甲酸钠、2,2'-联吡啶-4,4'-二甲酸钾、2,2'-联吡啶-4,4'-二甲酸铝、2,2'-联吡啶-4,4'-二甲酸镁、2,2'-联吡啶-4,4'-二甲酸钙、2,2'-联吡啶-4,4'-二甲酸铁、2,2'-联吡啶-4,4'-二甲酸钴、2,2'-联吡啶-4,4'-二甲酸镍、2,2'-联吡啶-4,4'-二甲酸锰中的至少一种。
在一些实施方式中，从提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能的观点考虑，所述膦类化合物可以包括选自二乙基苯基膦、三己基膦、三丁基膦、1,6-双(二苯基膦基)己烷、三(邻甲氧基苯基)膦、三正辛基膦、二苯基环己基膦、二苯基-2-吡啶膦、2-(二环己基膦基)联苯、2-(二叔丁基膦)联苯、二苯基乙氧基膦、三(2-呋喃基)膦、三环戊基膦、二乙基苯膦中的至少一种。
在一些实施方式中，所述除酸添加剂在所述隔离膜上的负载量可以为0.01g/m 2～20g/m 2，可选地为0.1g/m 2～5g/m 2。此外，所述除酸添加剂在所述隔 离膜上的负载量还可以为0.05g/m 2～20g/m 2，0.3g/m 2～19g/m 2，0.5g/m 2～18g/m 2，0.7g/m 2～17g/m 2，0.8g/m 2～16g/m 2，0.9g/m 2～15g/m 2，1.0g/m 2～14g/m 2，1.5g/m 2～12g/m 2，1.8g/m 2～11g/m 2，2.0g/m 2～10g/m 2，2.5g/m 2～8g/m 2，2.9g/m 2～7g/m 2，3.0g/m 2～6g/m 2，3.5g/m 2～5.5g/m 2，3.5g/m 2～5.0g/m 2，3.6g/m 2～4.8g/m 2，3.8g/m 2～4.6g/m 2，3.9g/m 2～4.3g/m 2和4.0g/m 2～4.7g/m 2。
在本申请中，负载在隔离膜上的除酸添加剂的量可以根据实际情况(例如根据电池体系和所选择的除酸添加剂的除酸能力)进行调节。除酸添加剂在隔离膜上的负载量可以设定为大于等于0.01g/m 2，由此可以有效降低电池体系中酸性物质的含量。另一方面，除酸添加剂在隔离膜上的负载量可以设定为小于等于20g/m 2，由此可以在不显著恶化隔离膜的透气性并且不明显增加电池内阻的情况下长期地、充分地保证除酸效果。
在一些实施方式中，所述无机颗粒和/或有机颗粒层的厚度可以为0.1μm～10μm，可选地为0.5μm～5μm。此外，所述无机颗粒和/或有机颗粒层的厚度可以为0.2μm～9μm，0.3μm～8.5μm，0.4μm～8μm，0.5μm～7.5μm，0.6μm～7.0μm，0.7μm～6.5μm，0.8μm～6.0μm，0.9μm～5.5μm，1.0μm～5.0μm，1.5μm～4.5μm，2.0μm～4.0μm，2.5μm～3.8μm，2.7μm～3.4μm和2.8μm～3.9μm。
在本申请中，所述无机颗粒和/或有机颗粒层的厚度可以根据实际情况(例如根据电池体系、所选择的除酸添加剂的除酸能力、除酸添加剂的尺寸等)进行调节。所述无机颗粒和/或有机颗粒层的厚度可以设定为大于等于0.5μm，由此可以有效地隔绝除酸添加剂与正负极界面的接触。另一方面，所述无机颗粒和/或有机颗粒层的厚度可以设定为小于等于10μm，由此可以在不显著恶化隔离膜的透气性(不会严重堵塞隔离膜的孔洞)并且不明显增加电池内阻的情况下保证除酸效果并且减少电池内部副反应的发生。
在一些实施方式中，对于无机颗粒没有特别限制，只要其具有电子绝缘性和适当的机械强度即可。由此，可以保证正负极活性材料不与隔离膜上的除酸添加剂接触，也不向除酸添加剂传导电子，使得除酸添加剂无法发生氧化还原反应，保证除酸添加剂在隔离膜上的稳定性。在本申请中，从提升电池的循环 性能和存储性能、尤其是高温循环性能和高温存储性能的观点考虑，所述无机颗粒可以包括选自由氧化硅、氧化铝、勃姆石、氧化镁、二氧化钛、氧化锌、氧化铝镁构成的组中的至少一种。类似地，在本申请发明中，对于有机颗粒没有特别限制，只要其具有电子绝缘性和适当的机械强度即可。从提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能的观点考虑，所述有机颗粒包括选自由聚氧化乙烯颗粒、聚偏氯乙烯颗粒、聚丙烯腈颗粒、聚偏二氟乙烯颗粒、聚甲基丙烯酸甲酯颗粒、聚偏二氟乙烯-六氟丙烯共聚物颗粒构成的组中的至少一种。
在一些实施方式中，所述电解液可以使用本领域常用的电解液。所述电解液可以包括溶剂和电解质盐。可选地，所述溶剂可以包括本领域中常用的溶剂，例如选自碳酸酯类溶剂、砜类溶剂、醚类溶剂、磺酸酯类溶剂、硫酸酯类溶剂和亚硫酸酯类溶剂中的至少一种。所述电解质盐可以包括锂盐或钠盐。
在一些实施方式中，所述基材可以使用本领域常用的作为隔离膜基材的基材。所述基材可以包括选自聚乙烯、聚丙烯、纤维素和聚酰亚胺中的至少一种。在本申请中，基材的厚度可以为1～20μm。可选地，基材的厚度可以为2～15μm，2～10μm，2.5～9μm，3～8μm，3.5～8μm，4～7.5μm，4.5～6μm和5～6.5μm。通过采用上述厚度，可以在保证绝缘性的同时确保隔离膜透气度、提高电池能量密度等。
本申请的第二方面提供一种电池模块，其包括本申请的第一方面提供的二次电池。
本申请的第三方面提供一种电池包，其包括本申请的第二方面提供的电池模块。
本申请的第四方面提供一种用电装置，其包括选自本申请的第一方面的二次电池、本申请的第二方面的电池模块或本申请的第三方面的电池包中的至少一种。
上述电池模块、电池包和用电装置包含本申请的二次电池，因此可以显著提升电池的循环性能和存储性能、尤其是高温循环性能和高温存储性能。
本申请的实施方式的详细说明
本申请的二次电池可以包括正极极片、负极极片以及设置在所述正极极片与所述负极极片之间的隔离膜和电解液。以下适当地参照附图对本申请的所述二次电池、电池模块、电池包和用电装置进行详细说明。
[负极极片]
负极极片可以包括负极集流体以及设置在负极集流体的至少一个表面上的负极膜片。所述负极膜片可以包括负极活性材料以及可选的粘结剂、导电剂和其他助剂。
作为示例，负极集流体具有在其自身厚度方向上相对的两个表面，负极膜片设置在负极集流体的相对的两个表面中的任一者或两者上。
在一些实施方式中，所述负极集流体可以采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可以包括高分子材料基材和形成于高分子材料基材的至少一个表面上的金属层。复合集流体可以通过将金属材料(如铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可以采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可以包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可以选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可以选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可以被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
此外，当二次电池为钠离子电池时，所述负极活性材料可以包含选自天然石墨、改性石墨、人造石墨、石墨烯、碳纳米管、碳纳米纤维、多孔碳、锡、锑、锗、铅、三氧化二铁、五氧化二钒、二氧化锡、二氧化钛、三氧化钼、单质磷、钛酸钠和对苯二甲酸钠中的至少一种。
在一些实施方式中，负极膜片还可以选择性地包括粘结剂。所述粘结剂可以选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜片还可以选择性地包括导电剂。导电剂可以选自超导碳、乙炔黑、炭黑、科琴黑、碳纳米管、碳纳米棒、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜片还可以选择性地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可以得到负极极片。可替代地，在另一个实施方式中，可以通过如下方式来制造负极极片：将用于形成负极膜片的负极浆料流延在单独的载体上，然后将通过从载体剥离而获得的膜层压在负极集流体上。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体的至少一个表面上且包括正极活性材料的正极膜片。作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜片设置在正极集流体相对的两个表面中的任意一者或两者上。
正极集流体可以采用具有良好导电性及机械强度的材质。在一些实施例中，正极集流体可以采用为铝箔。
本申请对正极活性材料的具体种类不做具体限制，可以采用本领域已知的能够用于二次电池正极的材料，本领域技术人员可以根据实际需求进行选择。
在一些实施例中，二次电池可以为锂离子二次电池。正极活性材料可选自锂过渡金属氧化物及其改性材料。改性材料可以是对锂过渡金属氧化物进行掺杂改性和/或包覆改性。例如，锂过渡金属氧化物可选自锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物及橄榄石结构的含锂磷酸盐中的一种或几种。
作为示例，二次电池的正极活性材料可选自LiCoO 2、LiNiO 2、LiMnO 2、LiMn 2O 4、LiNi 1/3Co 1/3Mn 1/3O 2(NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、LiNi 0.6Co 0.2Mn 0.2O 2(NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(NCM811)、LiNi 0.85Co 0.15Al 0.05O 2、LiFePO 4(LFP)和LiMnPO 4中的一种或几种。
此外，当所述二次电池为钠离子电池时，所述正极可以包含选自如下中的至少一种正极活性材料：层状过渡金属氧化物、聚阴离子化合物、普鲁士蓝类化合物、硫化物、氮化物、碳化物、钛酸盐。可选地，所述正极活性材料包括但不限于选自由NaCrO 2、Na 2Fe 2(SO 4) 3、二硫化钼、二硫化钨、二硫化钒、二硫化钛、六方氮化硼、碳掺杂六方氮化硼、碳化钛、碳化钽、碳化钼、碳化硅、Na 2Ti 3O 7、Na 2Ti 6O 13、Na 4Ti 5O 12、Li 4Ti 5O 12、NaTi 2(PO 4) 3构成的组中的至少一种。
在一些实施例中，正极膜片中还可选地包括粘结剂。对粘结剂的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。作为示例，用于正极膜片的粘结剂可包括聚偏二氟乙烯(PVDF)和聚四氟乙烯(PTFE)中的一种或几种。
在一些实施例中，正极膜片中还可选地包括导电剂。对导电剂的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。作为示例，用于正极膜片的导电剂可包括石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种或几种。
[电解液]
电解液在正极和负极之间起到传导离子的作用。本申请对电解液的种类没有具体的限制，可以根据需求进行选择。例如，电解液可以是液态的或凝胶态的。
此外，本申请的实施方式的电解液可以包含添加剂。所述添加剂可以包含本领域中常用的添加剂。所述添加剂可以包含例如卤代碳酸亚烷基酯类化合物(如二氟碳酸亚乙酯)、吡啶、亚磷酸三乙酯、三乙醇胺、环醚、乙二胺、(缩)甘醇二甲醚类、六甲基磷酸三酰胺、硝基苯衍生物、硫、醌亚胺染料、N-取代的唑烷酮、N,N-取代的咪唑烷、乙二醇二烷基醚、铵盐、吡咯、2-甲氧基乙醇或三氯化铝。此时，基于电解液的总质量，可以以0.1质量％至5质量％的量包含添加剂或者由本领域技术人员根据实际需要调整添加剂的用量。
一般而言，电解液可以包含电解质盐和溶剂。
在二次电池为锂离子电池的实施方式中，所述电解质盐可以包含选自LiPF 6、LiBF 4、LiN(SO 2F) 2(LiFSI)、LiN(CF 3SO 2) 2(LiTFSI)、LiClO 4、LiAsF 6、LiB(C 2O 4) 2(LiBOB)、LiBF 2C 2O 4(LiDFOB)中的至少一种。
在二次电池为钠离子电池的实施方式中，电解质盐可以包含选自NaPF 6、NaClO 4、NaBCl 4、NaSO 3CF 3及Na(CH 3)C 6H 4SO 3中的至少一种。
在一些实施方式中，除了上述提及的低粘度溶剂和高介电常数溶剂等溶剂以外，电解液还可以根据需要包含本领域常用的其他溶剂如选自1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜等中的至少一种。
[隔离膜]
本申请的隔离膜采用上述隔离膜。此外，根据需要，本申请的隔离膜可以与其它本领域常用的隔离膜组合使用。
[外包装]
在一些实施例中，二次电池可以包括外包装，用于封装正极极片、负极极片和电解液。作为一个示例，正极极片、负极极片和隔离膜可经叠片或卷绕形成叠片结构电池或卷绕结构电池，电池封装在外包装内；电解液浸润于电池中。二次电池中电池的数量可以为一个或几个，可以根据需求来调节。
在一些实施例中，二次电池的外包装可以是软包，例如袋式软包。软包的材质可以是塑料，如可包括聚丙烯PP、聚对苯二甲酸丁二醇酯PBT、聚丁二酸丁二醇酯PBS等中的一种或几种。二次电池的外包装也可以是硬壳，例如铝壳等。
在一些实施例中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的二次电池5。
[电池模块]
在本申请的第二方面，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图2是作为一个示例的电池模块4。参照图2，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的壳体，多个二次电池5容 纳于该容纳空间。
[电池包]
在本申请的第三方面，本申请的第二方面提供的电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图3和图4是作为一个示例的电池包1。参照图3和图4，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
[用电装置]
本申请的第四方面还提供一种用电装置，该用电装置包括本申请的第一方面的二次电池，所述二次电池为所述用电装置提供电源。所述用电装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能***等。
所述用电装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图5是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的用电装置可以是手机、平板电脑、笔记本电脑等。该用电装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试 剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1-48和对比例1-5的锂/钠离子电池均按照下述方法制备，具体隔离膜的构成示于下表1中。
(1)锂离子电池正极极片的制备
将正极活性材料锰酸锂、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按质量比为94:3:3溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体铝箔上，再经过烘干、冷压、分切，得到正极极片。
(2)锂离子电池负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为95:2:2:1溶于溶剂去离子水中。在与溶剂去离子水均匀混合后制备成负极浆料；然后将负极浆料一次或多次均匀涂覆在负极集流体铜箔上，再经过烘干、冷压、分切，得到负极极片。
(3)锂离子电池电解液的制备
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将有机溶剂碳酸亚乙酯/碳酸甲乙酯(EC/EMC)按照体积比3/7混合均匀得到混合溶剂。相对于混合溶剂的质量，加入12.5质量％的LiPF 6和作为添加剂的1质量％的1,3-丙烷磺酸内酯(PS)、0.5质量％的硫酸亚乙酯(DTD)和0.5质量％的碳酸亚乙烯酯(VC)，搅拌均匀后得到相应的电解液。
(4)钠离子电池正极极片的制备
将正极活性材料磷酸钒钠、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按质量比为80:15:3溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体铝箔上，再经过烘干、冷压、分切，得到正极极片。
(5)钠离子电池负极极片的制备
将活性材料硬碳、导电剂乙炔黑、粘结剂丁苯橡胶、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为91.6:1.6:4.8:2溶于溶剂去离子水中。在与溶剂去离子水均匀混合后制备成负极浆料；然后将负极浆料一次或多次均匀涂覆在负极集流体铝箔上，再经过烘干、冷压、分切，得到负极极片。
(6)钠离子电池电解液的制备
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将有机溶剂碳酸亚乙酯/碳酸甲乙酯(EC/EMC)按照体积比3/7混合均匀。相对于混合溶剂的质量，加入13.8质量％的NaPF 6锂盐和作为添加剂的1质量％的VC，搅拌均匀后得到相应的电解液。
(7)隔离膜的制备
分层涂布：首先将除酸添加剂溶解或分散在去离子水中，然后将溶解或分散好的除酸添加剂采用凹版法涂敷在基材聚乙烯上以得到除酸添加剂层，可采用多次涂敷获得所需负载量。再将不导电的无机颗粒原料和/或有机颗粒原料和水性聚丙烯酸酯粘结剂按质量比99：1分散在去离子水中获得无机和/或有机浆料，然后将无机和/或有机浆料涂敷在除酸添加剂层之上。可通过调控无机和/或有机浆料的涂敷质量获得所需厚度的无机颗粒和/或有机颗粒层。
混合涂布：
实施例30-33、实施例39、实施例40、实施例42、实施例45和实施例47(实施例47中聚偏二氟乙烯颗粒和勃母石的质量比为1:1)的混合涂布隔离膜：将除酸添加剂、不导电的无机颗粒原料和/或有机颗粒原料和水性聚丙烯酸酯粘结剂按质量比10:89:1分散在去离子水中获得无机和/或有机浆料，然后将无机和/或有机浆料涂敷在基材聚乙烯上，可通过调控无机和/或有机浆料的涂敷质量获得所需厚度的无机颗粒和/或有机颗粒层。
实施例35的混合涂布隔离膜：将除酸添加剂、不导电的无机粉料和水性聚丙烯酸酯粘结剂按质量比30:69:1分散在去离子水中获得无机浆料，然后将无机浆料涂敷在基材聚乙烯上，可通过调控无机浆料的涂敷质量获得所需厚度的无机颗粒层。
实施例36的混合涂布隔离膜：将除酸添加剂、不导电的无机粉料和水性聚丙烯酸酯粘结剂按质量比40:59:1分散在去离子水中获得无机浆料，然后将无机浆料涂敷在基材聚乙烯上，可通过调控无机浆料的涂敷质量获得所需厚度的无机颗粒层。
在本申请的实施例中，各除酸添加剂在25℃下在电解液中的最大溶解量是通过测量各除酸添加剂在25℃下在对应电解液中的最大溶解量并将该质量除以所溶解的除酸添加剂和电解液的总质量而得到的。
(8)锂/钠离子电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于电池壳体中，干燥后注入上述电解液，再经过化成、静置等工艺制得锂/钠离子电池。
表1
Figure PCTCN2021136599-appb-000005
Figure PCTCN2021136599-appb-000006
Figure PCTCN2021136599-appb-000007
Figure PCTCN2021136599-appb-000008
接下来说明相关参数的测试过程。
1.隔离膜透气度
透气度是指按规定条件，一定体积的空气在单位压力下，通过单位面积纸和纸板所用的时间。隔离膜的透气度测试参考GB/T458-2008进行测试，空气柱体积为100cc，测试面积为1平方英寸。
2.电池内阻(mΩ)
锂离子电池：在25℃下，将锂离子电池以1C恒流充电至4.3V，然后以4.3V恒压充电至电流小于0.05C，然后再以1C放电30min，即将电池的电量调整到50％SOC。然后将TH2523A交流内阻测试仪的正负表笔分别接触电池的正负极，通过内阻测试仪读取电池的内阻值。
钠离子电池：在25℃下，将钠离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后再以1C放电30min，即将电池的电量调整到50％SOC。然后将TH2523A交流内阻测试仪的正负表笔分别接触电池的正负极，通过内阻测试仪读取电池的内阻值。
3. 45℃循环800次容量保持率
锂离子电池：在45℃下，将锂离子电池以1C恒流充电至4.3V，然后以4.3V恒压充电至电流小于0.05C，然后将锂离子电池以1C恒流放电至3.0V，此为一个充放电过程。如此反复进行充电和放电，计算锂离子电池循环800次后的容量保持率。
锂离子电池45℃循环800次后的容量保持率(％)＝(第800次循环的放电容量/首次循环的放电容量)×100％。
钠离子电池：在45℃下，将钠离子电池以1C恒流充电至4.2V，然后以4.2V恒压充电至电流小于0.05C，然后将钠离子电池以1C恒流放电至2.0V，此为一个充放电过程。如此反复进行充电和放电，计算钠离子电池循环800次后的容量保持率。
钠离子电池45℃循环800次后的容量保持率(％)＝(第800次循环的放电容量/首次循环的放电容量)×100％。
4. 60℃存储50天体积膨胀率
锂离子电池：在25℃下，以1C恒流充电至电压为4.3V，然后以4.3V恒压充电至电流为0.05C，此时测试锂离子电池的体积并记为V21；然后将满充的锂离子电池放入60℃恒温箱中，存储50天，采用排水法测试体积并记为V31。
锂离子电池60℃存储50天后的体积膨胀率(％)＝(V31-V21)/V21×100％。
钠离子电池：在25℃下，以1C恒流充电至电压为4.2V，然后以4.2V恒压充电至电流为0.05C，此时测试钠离子电池的体积并记为V22；然后将满充的钠离子电池放入60℃恒温箱中，存储50天，采用排水法测试体积并记为V32。
钠离子电池60℃存储50天后的体积膨胀率(％)＝(V32-V22)/V22×100％。
下表2示出对比例1、3和4以及实施例4的测试数据。
表2
Figure PCTCN2021136599-appb-000009
Figure PCTCN2021136599-appb-000010
在对比例1中，未引入除酸添加剂，电池循环性能较差。这主要是因为高温下电解液跟电池体系中的痕量水反应生成酸，这些酸在正负极界面处发生反应，导致界面不稳定，由此需要持续消耗电解液来修复正负极界面。因此，电池的高温循环性能较差。同时，酸还会加剧正极活性材料中的过渡金属的溶出，从而进一步使电池高温性能恶化。
在对比例3和4中，添加了吡啶和三苯基膦除酸添加剂，由此能够抑制电解液中的酸性物质的含量，略微提升了电池循环性能。但是，吡啶和三苯基膦易溶解在电解液中，然后迁移到正负极界面处发生氧化还原反应，生成气态产物，导致电池高温存储性能恶化。同时，除酸添加剂被持续消耗，导致电池循环后期没有除酸添加剂的保护，使得改善循环性能的效果有限。
实施例4中的2,2'-联吡啶-4,4'-二甲酸锂能够显著提升电池的循环性能，这主要是由于如下原因。在充放电过程中，电解液中的酸性物质与隔离膜上的除酸添加剂2,2'-联吡啶-4,4'-二甲酸锂反应，从而可以将电池体系内的酸含量控制在较低水平。此外，在本申请中，除酸添加剂2,2'-联吡啶-4,4'-二甲酸锂以单独的层的形式被设置在基材与无机颗粒和/或有机颗粒层之间，并且在电解液中的溶解度低。因此，除酸添加剂2,2'-联吡啶-4,4'-二甲酸锂无法与正极和负极直接接触，从而彼此之间几乎不发生电化学氧化还原反应。这保证了除酸添加剂2,2'-联吡啶-4,4'-二甲酸锂在电池的整个寿命周期中存在于电池体系中。由此，可以显著提升电池的高温循环性能和高温存储性能。
下表3示出对比例1和实施例1-18的测试数据。
表3
Figure PCTCN2021136599-appb-000011
Figure PCTCN2021136599-appb-000012
通过对比对比例1和实施例1-18可以看出，在隔离膜上涂敷本申请的除酸添加剂能够有效改善电池在45℃下的循环性能；但是，涂敷太多会堵塞隔离膜孔洞，导致透气度值升高，隔离膜透气性变差，电池内阻显著恶化。所述除酸添加剂在隔离膜上的负载量为0.01g/m 2～20g/m 2，优选为0.1g/m 2～5g/m 2。
下表4示出对比例1、2和5以及实施例11和实施例19-47的测试数据。
表4
Figure PCTCN2021136599-appb-000013
Figure PCTCN2021136599-appb-000014
通过对比例1和5以及实施例11和实施例19-27的比较可以看出，2,2'-联吡啶-4,4'-二甲酸钾是不耐氧化还原的。如果上层没有无机颗粒和/或有机颗粒层进行保护，则其会与正极和负极直接接触，发生氧化还原反应，导致电池高温下产气。同时，这还会使除酸添加剂被持续消耗，导致电池循环后期没有除酸添加剂的保护，因此电池循环性能的改善不明显。由此可见，无机颗粒和/或有机颗粒层的阻挡效果会影响除酸添加剂对电池性能的改善效果。
由表4可以看出，常规电池如对比例1和对比例2的电池在60℃存储50天的体积膨胀率均较大。相比之下，本申请的实施例的电池的体积膨胀率可达到5％(实际上，考虑到测量误差等，5％的体积膨胀率基本上是可测量的下限值)。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请 主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (13)

  1. 一种二次电池，其包括正极极片、负极极片以及设置在所述正极极片与所述负极极片之间的隔离膜和电解液，其中，
    所述隔离膜包括基材和设置于所述基材的至少一个表面之上的无机颗粒和/或有机颗粒层，并且
    所述隔离膜还包括除酸添加剂，所述除酸添加剂位于所述无机颗粒和/或有机颗粒层的无机颗粒和/或有机颗粒之间或者以单独的层的形式位于所述基材与所述无机颗粒和/或有机颗粒层之间，
    相对于所述电解液的质量，所述除酸添加剂在25℃下在所述电解液中的最大溶解量为小于1质量％。
  2. 根据权利要求1所述的二次电池，其中，所述除酸添加剂包括选自吡啶类化合物和膦类化合物中的至少一种，
    所述吡啶类化合物为选自化学式Ⅰ、化学式Ⅱ和化学式Ⅲ所示的化合物中的至少一种：
    Figure PCTCN2021136599-appb-100001
    所述膦类化合物为选自化学式Ⅳ所示的化合物中的至少一种：
    Figure PCTCN2021136599-appb-100002
    其中，R 1～R 13和R 15～R 17各自独立地为选自如下中的一种：碳原子数为1～20的烷基，碳原子数为2～20的烯基，碳原子数为6～26的芳基，碳原子数为6～26的芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，H，F，Cl和Br；R 14为选自如下中的一种：碳原子数为1～20的次烷基，碳原子数为2～20的次烯基，碳原子数为7～26的次芳基，碳原子数为7～26的次芳氧基及它们被F、Cl、Br、磺酸基或磺酰基取代所形成的基团，n为大于 等于2的整数。
  3. 根据权利要求2所述的二次电池，其中，所述吡啶类化合物包括选自异烟酸盐、2-羟基吡啶-4-羧酸盐、2,2'-联吡啶-4,4'-二甲酸盐和聚(4-乙烯吡啶)中的至少一种。
  4. 根据权利要求3所述的二次电池，其中，
    所述异烟酸盐包括选自异烟酸锂、异烟酸钠、异烟酸钾、异烟酸铝、异烟酸镁、异烟酸钙、异烟酸铁、异烟酸钴、异烟酸镍、异烟酸锰中的至少一种；
    所述2-羟基吡啶-4-羧酸盐包括选自2-羟基吡啶-4-羧酸锂、2-羟基吡啶-4-羧酸钠、2-羟基吡啶-4-羧酸钾、2-羟基吡啶-4-羧酸铝、2-羟基吡啶-4-羧酸镁、2-羟基吡啶-4-羧酸钙、2-羟基吡啶-4-羧酸铁、2-羟基吡啶-4-羧酸钴、2-羟基吡啶-4-羧酸镍、2-羟基吡啶-4-羧酸锰中的至少一种；并且
    所述2,2'-联吡啶-4,4'-二甲酸盐包括选自2,2'-联吡啶-4,4'-二甲酸钠、2,2'-联吡啶-4,4'-二甲酸钾、2,2'-联吡啶-4,4'-二甲酸铝、2,2'-联吡啶-4,4'-二甲酸镁、2,2'-联吡啶-4,4'-二甲酸钙、2,2'-联吡啶-4,4'-二甲酸铁、2,2'-联吡啶-4,4'-二甲酸钴、2,2'-联吡啶-4,4'-二甲酸镍、2,2'-联吡啶-4,4'-二甲酸锰中的至少一种。
  5. 根据权利要求2所述的二次电池，其中，所述膦类化合物包括选自二乙基苯基膦、三己基膦、三丁基膦、1,6-双(二苯基膦基)己烷、三(邻甲氧基苯基)膦、三正辛基膦、二苯基环己基膦、二苯基-2-吡啶膦、2-(二环己基膦基)联苯、2-(二叔丁基膦)联苯、二苯基乙氧基膦、三(2-呋喃基)膦、三环戊基膦、二乙基苯膦中的至少一种。
  6. 根据权利要求1～5中任一项所述的二次电池，其中，所述除酸添加剂在所述隔离膜上的负载量为0.01g/m 2～20g/m 2，可选地为0.1g/m 2～5g/m 2。
  7. 根据权利要求1～6中任一项所述的二次电池，其中，所述无机颗粒和/或有机颗粒层的厚度为0.1μm～10μm，可选地为0.5μm～5μm。
  8. 根据权利要求1～7中任一项所述的二次电池，其中，所述无机颗粒包 括选自由氧化硅、氧化铝、勃姆石、氧化镁、二氧化钛、氧化锌、氧化铝镁构成的组中的至少一种；所述有机颗粒包括选自由聚氧化乙烯颗粒、聚偏氯乙烯颗粒、聚丙烯腈颗粒、聚偏二氟乙烯颗粒、聚甲基丙烯酸甲酯颗粒、聚偏二氟乙烯-六氟丙烯共聚物颗粒构成的组中的至少一种。
  9. 根据权利要求1～8中任一项所述的二次电池，其中，所述电解液包括溶剂和电解质盐，可选地，所述溶剂包括选自碳酸酯类溶剂、砜类溶剂、醚类溶剂、磺酸酯类溶剂、硫酸酯类溶剂和亚硫酸酯类溶剂中的至少一种；并且所述电解质盐包括锂盐或钠盐。
  10. 根据权利要求1～9中任一项所述的二次电池，其中，所述基材包括选自聚乙烯、聚丙烯、纤维素和聚酰亚胺中的至少一种。
  11. 一种电池模块，其包括权利要求1～10中任一项所述的二次电池。
  12. 一种电池包，其包括权利要求11所述的电池模块。
  13. 一种用电装置，其包括选自权利要求1～10中任一项所述的二次电池、权利要求11所述的电池模块或权利要求12所述的电池包中的至少一种。
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