WO2023028894A1 - 改性石墨的制备方法、二次电池、电池模块、电池包和用电装置 - Google Patents

改性石墨的制备方法、二次电池、电池模块、电池包和用电装置 Download PDF

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WO2023028894A1
WO2023028894A1 PCT/CN2021/115840 CN2021115840W WO2023028894A1 WO 2023028894 A1 WO2023028894 A1 WO 2023028894A1 CN 2021115840 W CN2021115840 W CN 2021115840W WO 2023028894 A1 WO2023028894 A1 WO 2023028894A1
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modified graphite
optionally
graphitization
heat treatment
battery
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PCT/CN2021/115840
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English (en)
French (fr)
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宋子龙
沈睿
何立兵
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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 EP21928350.4A priority Critical patent/EP4174990A4/en
Priority to JP2022553132A priority patent/JP2023545335A/ja
Priority to PCT/CN2021/115840 priority patent/WO2023028894A1/zh
Priority to CN202180084973.6A priority patent/CN116648428A/zh
Priority to KR1020227030833A priority patent/KR20230035215A/ko
Priority to US17/942,080 priority patent/US20230183073A1/en
Publication of WO2023028894A1 publication Critical patent/WO2023028894A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/205—Preparation
    • 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
    • H01M10/05—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/54—Reclaiming serviceable parts of waste accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/51—Particles with a specific particle size distribution
    • C01P2004/53—Particles with a specific particle size distribution bimodal size distribution
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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 lithium batteries, in particular to a modified graphite, a secondary battery, a battery module, a battery pack and an electrical device.
  • lithium-ion secondary batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles , electric vehicles, military equipment, aerospace and other fields. Due to the great development of lithium-ion secondary batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • Graphite has become the first choice for modified graphite in commercial lithium-ion secondary batteries because of its low cost, convenient production, and actual capacity close to the theoretical capacity.
  • Graphite is usually used as a negative electrode material, including natural graphite and artificial graphite, but the defects on the surface of artificial graphite are usually highly active, and are prone to side reactions with the electrolyte, consuming active lithium; and the loss of active lithium ions will reduce the lithium-ion secondary battery. Cycle performance, and will damage the service life of lithium-ion secondary batteries. Therefore, the existing modification technology for artificial graphite still needs to be improved.
  • This application is carried out in view of the above-mentioned problems, and its purpose is to provide a method for preparing modified graphite, which can make the secondary battery containing the modified graphite have higher energy density, better cycle performance and safety performance .
  • the present application provides a preparation method of modified graphite, a secondary battery, a battery module, a battery pack and an electrical device.
  • the first aspect of the present application provides a kind of preparation method of modified graphite
  • Crushing step crushing the coal-based needle coke to obtain material A.
  • Shaping step Shaping the material A and removing fine powder to obtain material B.
  • Heat treatment step put the material B in a reactor for heat treatment, then cool to room temperature to obtain material C.
  • Graphitization step place the material C in a high-temperature graphite furnace for high-temperature graphitization, then cool to room temperature, and the obtained product is modified graphite.
  • the present application selects the coal-based needle coke containing volatile matter as the precursor, and through closed heat treatment, the volatile matter contained in the coal-based needle coke is released and enriched on the surface of the coal-based needle coke precursor , uniformly coated on the surface of the coal-based needle coke precursor, that is, self-coating before graphitization.
  • the obtained modified graphite has a coating layer, and when used as a negative electrode material, the first Coulombic efficiency of the secondary battery can be improved.
  • the coating layer it has reduces the surface roughness of the modified graphite, repairs the surface defects of the modified graphite, and makes the value of the specific surface area BET in a suitable range.
  • coal-based needle coke is obtained by pyrolysis of coal tar pitch.
  • Coal tar pitch is a complex mixture containing a large amount of condensed ring aromatics, which has suitable intermolecular forces. Compared with petroleum pitch, it has higher aromaticity and higher carbon yield. Therefore, coal tar pitch is an ideal raw material for the synthesis of high-quality needle coke.
  • coal tar pitch is usually pretreated, followed by delayed coking and high-temperature calcination, and finally coal-based needle coke is obtained.
  • Examples of the coal-based needle coke include Nichika Coke, Mitsubishi Coke, Anshan Coke, and the like.
  • the coal-based needle coke satisfies: by mass percentage, the volatile content: 5-9%, optionally, the content is 6-8%; the sulfur content is less than or equal to 0.2%, optionally, the content Less than or equal to 0.1%; the ash content is less than or equal to 0.2%, and optionally the content is less than or equal to 0.1%.
  • the quinoline insoluble content is less than or equal to 0.2%, and optionally the content is less than or equal to 0.1%.
  • the true density is 1.35-1.48 g/cm 3 , optionally 1.39-1.45 g/cm 3 .
  • this application selects coal-based needle coke with specific components as raw materials, and the volatile matter contained in it can be used as a coating agent, and a coating layer can be formed on the surface without adding additional coating agents. , when used as an anode material, it can improve the interface performance of the anode material.
  • the volatile matter refers to the thermal decomposition of the organic substances in the coal-based needle coke to produce a part of liquid (at this time in a steam state) and gaseous products with a relatively small molecular weight.
  • the ash content refers to the inorganic substances (such as iron oxides, silicon oxides, etc.) that remain after the coal-based needle coke is fired in an air or oxygen atmosphere.
  • the heat treatment temperature is 400-800°C, optionally 500-700°C; the constant temperature time is 2-8 hours, optionally 3-6 hours. Therefore, this application selects the heat treatment temperature and constant temperature time within the above range, so that the volatile matter in the coal-based needle coke can be released and fully melted, and a uniform coating layer can be formed on the surface of the particles.
  • the heating rate is 1-15°C/min, optionally, 5-12°C/min. Therefore, by selecting the heating rate within the above range in the present application, the coal-based needle coke can be heated at a uniform speed, and the volatile matter can overflow slowly and evenly adhere to the surface of the particles to form a coating layer.
  • the graphitization temperature is 2500-3200° C.; the graphitization holding time is 55-65 hours. Therefore, the present application selects the graphitization temperature and graphitization holding time within the above range to make it have a good degree of graphitization.
  • the secondary battery made has excellent first-time Coulombic efficiency and cycle performance.
  • the second aspect of the present application provides a modified graphite prepared according to the method of the first aspect of the present application.
  • the third aspect of the present application provides a negative electrode sheet, including the modified graphite according to the second aspect of the present application.
  • a fourth aspect of the present application provides a secondary battery, including the negative electrode sheet of the third aspect of the present application.
  • a fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
  • a sixth aspect of the present application provides a battery pack, including the battery module of the fifth aspect of the present application.
  • the seventh aspect of the present application provides an electric device, including at least one selected from the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. kind.
  • the application provides a preparation method of modified graphite, a negative electrode sheet, a secondary battery, a battery module, a battery pack, and an electrical device.
  • the raw material contains a certain amount of volatile matter.
  • the coal-based needle coke is sealed and heat-treated to make the volatile matter contained in it escape and enrich on the surface of the precursor. , so that the surface of the precursor is uniformly covered, that is, self-coated before graphitization.
  • the obtained modified graphite has a coating layer, which reduces the surface roughness of the modified graphite, repairs the surface defects of the modified graphite, and reduces the consumption of active lithium ions by the modified graphite and the interaction with the electrolyte. Side reactions, thereby improving the first coulombic efficiency of the secondary battery containing the modified graphite, thereby having better cycle performance and service life.
  • Fig. 1 is the scanning electron micrograph of the modified graphite of the present application.
  • FIG. 2 is the first charge and discharge diagram of Example 1 of the present application.
  • FIG. 3 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 3 .
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 6 .
  • FIG. 8 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 “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • the application proposes a preparation method of modified graphite:
  • Crushing step crushing the coal-based needle coke to obtain material A;
  • Shaping step shaping the material A and removing fine powder to obtain material B;
  • Heat treatment step placing the material B in a reactor for heat treatment, then cooling to room temperature to obtain material C;
  • Graphitization step place the material C in a graphite furnace for graphitization, then cool to room temperature, and the obtained product is the negative electrode material.
  • coal-based needle coke is obtained by pyrolysis of coal tar pitch.
  • Coal tar pitch is a complex mixture containing a large amount of condensed ring aromatics, which has suitable intermolecular forces. Compared with petroleum pitch, it has higher aromaticity and higher carbon yield. Therefore, coal tar pitch is an ideal raw material for the synthesis of high-quality needle coke.
  • coal tar pitch is usually pretreated, followed by delayed coking and high-temperature calcination, and finally coal-based needle coke is obtained.
  • Examples of the coal-based needle coke include Nichika Coke, Mitsubishi Coke, Anshan Coke, and the like.
  • FIG. 1 is a scanning electron microscope image of the modified graphite obtained.
  • the modified graphite in the figure has a smooth and flat particle surface, which proves that the coating effectively reduces the surface roughness of the modified graphite and restores the surface roughness of the modified graphite.
  • Surface defects reduce the side reaction between the surface of the modified graphite and the electrolyte, and achieve the purpose of improving its first Coulombic efficiency.
  • the coal-based needle coke satisfies: by mass percentage, volatile matter content: 5-9%, optionally, the content is 6-8%; sulfur content is less than or equal to 0.2%, optional Specifically, the content is less than or equal to 0.1%; the ash content is less than or equal to 0.2%, optionally the content is less than or equal to 0.1%; the quinoline insoluble content is less than or equal to 0.2%, and the optional content is less than or equal to 0.1%; the true density is 1.35-1.48g /cm 3 , optionally 1.39 to 1.45 g/cm 3 .
  • Coal-based needle coke is used as a precursor, and the volatile components contained in itself can be used as a coating agent, and a coating layer can be formed on the surface without adding additional coating agents, thereby modifying the defects on the particle surface and reducing the roughness of the particle surface.
  • the modified graphite modified by the coating layer reduces the consumption of active lithium ions, and thus improves the first Coulombic efficiency.
  • the true density of the precursor has a certain influence on the tap density of the prepared modified graphite. Therefore, by selecting coal-based needle coke with a true density within the above range as a precursor, the prepared modified graphite also has a better tap density, which in turn can increase the energy density of a secondary battery using the modified graphite.
  • the heat treatment temperature is 400-800°C, optionally 500-700°C; the constant temperature time is 2-8 hours, optionally 3-6 hours.
  • Heat treatment temperature and constant temperature time are very important for forming the coating layer of modified graphite. If the heat treatment temperature is within the above range, the following situation can be avoided: if the heat treatment temperature is too low and the constant temperature time is too short, the volatile matter in the coal-based needle coke may not be able to fully melt and overflow, forming a coating layer on the particle surface, Therefore, the effect of modifying the surface defects of the particles may be lost; if the heat treatment temperature is too high and the constant temperature time is too long, it may cause excessive energy consumption in the production process, increase production costs, and cause unnecessary waste.
  • the heat treatment temperature and constant temperature time within the above range can allow the volatile matter in the coal-based needle coke to overflow and fully melt, form a uniform coating layer on the surface of the particles, reduce the consumption of active lithium ions and improve The first coulombic efficiency; at the same time, there is no additional production cost due to high energy consumption.
  • the heating rate is 1-15°C/min, optionally, 5-12°C/min. If the heat treatment is within the above range, the following situation can be avoided: the heating rate is too fast, and the volatile matter of the coal-based needle coke may overflow quickly in a short time when it reaches the heat treatment temperature, and the volatile matter cannot evenly wrap the surface of the particles. Can cause particle agglomeration. That is to say, at the heating rate within the above range, the coal-based needle coke can be heated evenly and at a constant speed, and the volatile matter can be evenly and slowly attached to the particle surface to form a coating layer, and the corresponding modified graphite also has high First Coulombic efficiency and then good cycle performance.
  • the graphitization temperature is 2500-3200° C.; the graphitization holding time is 55-65 hours.
  • the graphitization temperature and graphitization holding time within the above range make the modified graphite prepared by this method have a good degree of graphitization, and the good interlayer distance facilitates the intercalation and extraction of lithium ions, thereby improving the first time of the modified graphite. Coulombic efficiency and cycle performance.
  • Dv50 5 ⁇ 12 ⁇ m, optionally, 8 ⁇ 11 ⁇ m; and, 5 ⁇ m ⁇ Dn10 ⁇ 1.5 ⁇ m, optionally 5 ⁇ m ⁇ Dn10 ⁇ 2.0 ⁇ m .
  • Crushing the raw materials to the above particle size ensures that when the raw materials are heat-treated and graphitized, the raw materials are heated evenly and sufficiently, and the particle size distribution is uniform.
  • the modified graphite obtained has uniform particle size distribution, complete coating layer, and graphitization The density is high, and when the modified graphite is used as the negative electrode material, the first Coulombic efficiency is high and the cycle performance is good.
  • the volatile content of the coal-based needle coke can be tested by methods known in the art. For example, it is measured with reference to YB/T5189-2007.
  • the sulfur content of the coal-based needle coke can be tested by methods known in the art, for example, it can be measured with reference to GB/T 2286-2008.
  • the ash content of the coal-based needle coke can be tested by methods known in the art, for example, it can be measured with reference to GB/T 1429-2009.
  • the quinoline-insoluble matter refers to quinoline-insoluble components in coal-based needle coke, and the content of quinoline-insoluble matter in the coal-based needle coke can be tested by methods known in the art, for example, refer to GB/T2293 -97 for determination.
  • the average volume distribution particle diameter Dv50 refers to the corresponding particle diameter when the cumulative volume distribution percentage of the modified graphite reaches 50%.
  • the volume average particle diameter Dv50 of the modified graphite can be measured by laser diffraction particle size analysis. For example, with reference to the standard GB/T 19077-2016, use a laser particle size analyzer (such as Malvern Master Size 3000) to measure.
  • the specific surface area (BET) test of described modified graphite can use specific surface area analyzer, according to " gas adsorption BET method measures solid substance specific surface area " GB/T 19587-2017/ISO9277:2010 test sample specific surface area.
  • the true density of the modified graphite can use a tap density tester to test the sample tap density according to "Measurement of Metal Powder Tap Density" GB/T 5162-2006.
  • a secondary battery is provided.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, and the positive electrode film layer includes a positive electrode material.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • positive electrode materials known in the art for batteries can be used as the positive electrode material.
  • the cathode material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as battery cathode materials can also be used.
  • These positive electrode materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon At least one of a composite material, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also may be abbreviated as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer may also optionally include a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer may also optionally include a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared in the following manner: the above-mentioned components for preparing the positive electrode sheet, such as positive electrode material, conductive agent, binding agent and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N-methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes the modified graphite according to the second aspect of the present application.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • the negative electrode film layer 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 film layer 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 dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may 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 material, conductive agent, binder and any other components, are dispersed in a solvent (such as ionized water) to form the negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as ionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may optionally include additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • Secondary batteries using electrolytes and some secondary batteries using solid electrolytes also include a separator.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • 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.
  • the secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 3 shows a square-shaped secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating chamber. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 5 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 also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art 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.
  • the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include 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, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 8 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.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • Coal-based needle coke raw materials were crushed using a LHJ type mechanical pulverizer (manufacturer: Weifang Zhengyuan Powder Engineering Equipment Co., Ltd.). Wherein, the sulfur content in the coal-based needle coke is 0.08%, the ash content is 0.05%, the volatile matter content is 5.1%, and the true density is 1.42g/cm 3 .
  • the reshaped material was placed in a WHR type horizontal heating reactor (manufacturer: Wuxi Qingxin Powder Equipment Co., Ltd.) for heat treatment, and heated at 10°C/min to 600°C for 4 hours. Add the heat-treated product into a graphitization furnace, raise the temperature to 3000° C. and keep it for 60 hours for high-temperature graphitization to obtain artificial graphite.
  • Coal-based needle coke raw materials were crushed using a LHJ type mechanical pulverizer (manufacturer: Weifang Zhengyuan Powder Engineering Equipment Co., Ltd.). Among them, the sulfur content in the coal-based needle coke is 0.08%, the ash content is 0.05%, the volatile content is 1.2%, the quinoline insoluble content is 0.04%, and the true density is 1.4g/cm 3 .
  • the reshaped material was placed in a WHR type horizontal heating reactor (manufacturer: Wuxi Qingxin Powder Equipment Co., Ltd.) for heat treatment, and heated at 10°C/min to 600°C for 4 hours. Add the heat-treated product into a graphitization furnace, raise the temperature to 3000° C. and keep it for 60 hours for high-temperature graphitization to obtain artificial graphite.
  • the modified graphites obtained in the above-mentioned Examples 1-10 and Comparative Examples 1-6 were respectively subjected to the average volume particle size distribution test, BET test, graphitization degree test, and tap density test. The test results are shown in Table 2 below.
  • Table 2 Test results of average volume particle size distribution, BET, degree of graphitization, and tap density of modified graphite in Examples 1-10 and Comparative Examples 1-6
  • Example 1 9.0 5.4 1.34 95.3 1.21
  • Example 2 10.5 5.3 1.35 95.1 1.18
  • Example 3 9.7 5.8 1.37 95.0 1.17
  • Example 4 9.5 6.1 1.38 95.2 1.20
  • Example 5 10.2 5.4 1.33 95.3 1.18
  • Example 6 8.8 5.1 1.35 95.2 1.19
  • Example 7 9.1 5.5 1.36 95.3 1.18
  • Example 8 9.5 5.1 1.31 95.1 1.23
  • the positive electrode material, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are mixed in an N-methylpyrrolidone solvent system at a weight ratio of 94:3:3, and then coated on an aluminum foil and dried. and cold pressing to obtain the positive electrode sheet.
  • PVDF polyvinylidene fluoride
  • a porous polymer film made of polyethylene (PE) is used as the separator.
  • the positive electrode sheet, the separator and the negative electrode sheet are stacked in order, so that the separator is placed between the positive and negative electrodes to play the role of isolation, and the bare cell is obtained by winding.
  • Each of the secondary batteries prepared above was first charged at 25°C at 1/3C to 3.65V (C is the nominal capacity of the battery), charged at a constant voltage of 3.65V to 0.05C, and then discharged at 1/3C to 2.5V and recorded.
  • the capacity is C 0 .
  • the cycle performance of the battery is tested at 45°C.
  • the battery is charged and discharged at a rate of 1C 0 /1C 0 between 2.5 and 3.65V.
  • the discharge capacity C 100 of the 100th cycle of the battery is The retention ratio was C 100 /C 0 .
  • Table 3 The results of the initial gram capacity and the first Coulombic efficiency test of Examples 1-10 and Comparative Examples 1-6, and the cycle performance test of the secondary battery at 45°C
  • FIG. 2 is the first charge and discharge diagram of the modified graphite in Example 1 of the present application.
  • the modified graphite in Example 1 exhibited excellent electrochemical properties: the first discharge gram capacity was 376.9mAh/g, the first charge gram capacity was 358.1mAh/g, and the first coulombic efficiency was 95.0%.
  • the first coulombic efficiencies of the modified graphite in Examples 1-10 are all greater than or equal to 95.0%, and the capacity retention rates after 100 cycles at 45° C. are all greater than 97.0%.
  • Comparative Example 1 Under the same heat treatment process conditions as in Example 1, due to the low volatile content of coal-based needle coke, the volatile content cannot be fully and uniformly wrapped on the surface of the particles, resulting in a coating layer The interfacial properties of graphite cannot be sufficiently improved, so the first Coulombic efficiency of the prepared modified graphite is low.
  • Comparative Example 2 and Comparative Example 4 with those of Examples 1-10, ordinary petroleum coke was used as the raw material.
  • the ordinary petroleum coke produced a cohesive effect during heat treatment, resulting in particle agglomeration, which failed to effectively improve the first Coulombic efficiency of the prepared modified graphite.
  • Comparative Example 3 Comparative Example 5 and Comparative Example 6 and Example 1 mainly lies in the heat treatment temperature and heat treatment time.
  • the heat treatment of the coal-based needle coke was canceled, and the volatile matter could not be evenly coated on the surface of the particles to form a coating layer, because the interface properties of the modified graphite could not be improved, so its cycle performance and the first time
  • the Coulombic efficiencies are not as good as those of the modified graphite in Examples 1-10.
  • the heat treatment temperature was low, the volatile components could not be fully enriched on the particle surface, and the heat treatment time was short, so the volatile components could not form a complete core-shell structure and thus improve the particle surface.
  • the modified graphite in Examples 1-10 has a larger tap density.
  • the negative electrode material with high tap density also ensures the overall energy density of the secondary battery.
  • 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

本申请提供了改性石墨的制备方法、二次电池、电池模块、电池包和用电装置。所述改性石墨的制备方法，其特征在于，包括以下步骤：破碎步骤：将煤系针状焦破碎，得到物料A；整形步骤：将物料A进行整形并去细粉，得到物料B；热处理步骤：将物料B置于反应釜中进行热处理后，冷却至室温，得到物料C；石墨化步骤：将物料C置于石墨炉中进行石墨化后，冷却至室温，所得产物即为改性石墨。

Description

改性石墨的制备方法、二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种改性石墨、二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着锂离子二次电池的应用范围越来越广泛，锂离子二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子二次电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。石墨因其成本低廉、生产方便、实际容量接近理论容量成为了商业锂离子二次电池的改性石墨的首选。
石墨通常作为负极材料，包括天然石墨和人造石墨等，但是人造石墨表面的缺陷通常活性较高，容易与电解液发生副反应，消耗活性锂；而活性锂离子的损失会降低锂离子二次电池的循环性能，并且会损害锂离子二次电池的使用寿命。因此，现有的对人造石墨的改性技术仍有待改进。
发明内容
发明所要解决的技术问题
本申请是鉴于上述课题而进行的，其目的在于，提供一种改性石墨的制备方法，能够使包含该改性石墨的二次电池具有较高的能量密度、较好的循环性能和安全性能。
为了达到上述目的，本申请提供了一种改性石墨的制备方法、二次电池、电池模块、电池包和用电装置。
用于解决问题的技术方案
本申请的第一方面提供了一种改性石墨的制备方法，
破碎步骤：将煤系针状焦破碎，得到物料A。
整形步骤：将所述物料A进行整形并去细粉，得到物料B。
热处理步骤：将所述物料B置于反应釜中进行热处理后，冷却至室温，得到物料C。
石墨化步骤：将所述物料C置于高温石墨炉中进行高温石墨化后，冷却至室温，所得产物即为改性石墨。
由此，本申请通过选择以含有挥发分的煤系针状焦作为前驱体，通过密闭热处理，使煤系针状焦所含的挥发分逸出并富集到煤系针状焦前驱体表面，均匀包覆在煤系针状焦前驱体表面，即石墨化前的自包覆。石墨化后，得到改性石墨具有包覆层，作为负极材料使用时，能够提高二次电池的首次库仑效率。虽然机理尚不十分清楚，但推测是，其所具有的包覆层降低了改性石墨的表面粗糙度，修复了改性石墨的表面缺陷，使其比表面积BET的数值在适合的范围。
其中，煤系针状焦是由煤沥青热解得到的。煤沥青是含有大量稠环芳烃的复杂混合物，具有合适的分子间作用力，与石油沥青相比，芳香度高、碳收率大，因此煤焦油沥青是合成高品质针状焦的理想原料。作为煤系针状焦的制备方法，通常是将煤沥青经预处理后，进行延迟焦化并高温煅烧，最后得到煤系针状焦。作为煤系针状焦，可列举出新日化焦、三菱焦、鞍山焦等。
在任意实施方式中，煤系针状焦满足：以质量百分数计，挥发分含量：5～9％，可选地，含量为6～8％；硫含量小于等于0.2％，可选地，含量小于等于0.1％；灰分含量小于等于0.2％，可选地含量小于等于0.1％。喹啉不溶物含量小于等于0.2％，可选地含量小于等于0.1％。真密度为1.35～1.48g/cm 3，可选地1.39～1.45g/cm 3。由此，本申请通过选取有特定组分的煤系针状焦作为原料，其自身所含有的挥发分就可作为包覆剂，不需额外添加包覆剂，便能在表面形成包覆层，作为负极材料使用时，能够改善负极材料的界面性能。其中，所述挥发分是指煤系针状焦中的有机物质受热分解出一部分分子量较小的液态(此时为蒸汽状态)和气态产物。所述灰分是指煤系针状焦经在空气或氧气气氛下灼烧后，最后残留下来的无机物(如铁氧化物、硅氧化物等)。
在任意实施方式中，热处理步骤中，热处理温度为400～800℃，可选地500～700℃；恒温时间为2～8小时，可选地3～6小时。由此，本申请通过选取上述范围内的热处理温度和恒温时间，能够使煤系针状焦中的挥发分逸出 并充分熔融，在颗粒表面形成均匀的包覆层。
在任意实施方式中，热处理步骤中，升温速率为1～15℃/min，可选地，5～12℃/min。由此，本申请通过选取上述范围内的升温速率，能够使煤系针状焦匀速升温，挥发分能缓慢地溢出，均匀地附着于颗粒表面，形成包覆层。
在任意实施方式中，石墨化步骤中，石墨化温度为2500～3200℃；石墨化保温时间为55～65小时。由此，本申请通过选取上述范围内的石墨化温度和石墨化保温时间，使其具有良好的石墨化度，作为负极材料时，制成的二次电池具有优良的首次库仑效率及循环性能。
在任意实施方式中，整形步骤中，物料B需满足Dv50＝5～12μm，可选地，8～11μm，且，5μm≥Dn10≥1.5μm，可选地，5μm≥Dn10≥2.0μm。由此，本申请通过选取具有上述粒径大小的物料B，方便后续工艺的处理，从而得到电化学性能优良的改性石墨。
在任意实施方式中，破碎步骤中，物料A：Dv50＝3～12μm，可选地，Dv50＝6～9μm。由此，本申请通过将原料破碎至上述的粒径大小，从而保证后续加工的便捷性，制得的负极材料具有良好的电化学性能。
本申请的第二方面提供一种改性石墨，根据本申请第一方面的方法制得。
本申请的第三方面提供一种负极极片，包括本申请第二方面的改性石墨。
本申请的第四方面提供一种二次电池，包括本申请第三方面的负极极片。
本申请的第五方面提供一种电池模块，包括本申请的第四方面的二次电池。
本申请的第六方面提供一种电池包，包括本申请的第五方面的电池模块。
本申请的第七方面提供一种用电装置，包括选自本申请的第四方面的二次电池、本申请的第五方面的电池模块或本申请的第六方面的电池包中的至少一种。
发明效果
本申请提供了改性石墨制备方法、负极极片、二次电池、电池模块、电池包、用电装置。通过选择煤系针状焦作为原料，该原料含有一定含量的挥发分，在石墨化前，通过对煤系针状焦密闭热处理，使其所含的挥发分逸出并富集到前驱体表面，使得前驱体表面得到均匀包覆，即石墨化前的自包覆。石墨化后，得到的改性石墨具有包覆层，降低了改性石墨的表面粗糙度，修复了改性石墨 的表面缺陷，减少改性石墨对活性锂离子的消耗及与电解液之间的副反应，从而提高了包含该改性石墨的二次电池的首次库仑效率，进而具有更佳的循环性能和使用寿命。
附图说明
图1为本申请的改性石墨的扫描电镜图。
图2为本申请实施例1的首次充放电图。
图3是本申请一实施方式的二次电池的示意图。
图4是图3所示的本申请一实施方式的二次电池的分解图。
图5是本申请一实施方式的电池模块的示意图。
图6是本申请一实施方式的电池包的示意图。
图7是图6所示的本申请一实施方式的电池包的分解图。
图8是本申请一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；5二次电池；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改性石墨及其制造方法、负极极片、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。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
改性石墨的制备
本申请的一个实施方式中，本申请提出了一种改性石墨的制备方法：
破碎步骤：将煤系针状焦破碎，得到物料A；
整形步骤：将所述物料A进行整形并去细粉，得到物料B；
热处理步骤：将所述物料B置于反应釜中进行热处理后，冷却至室温，得到物料C；
石墨化步骤：将所述物料C置于石墨炉中进行石墨化后，冷却至室温，所得产物即为所述负极材料。
其中，煤系针状焦是由煤沥青热解得到的。煤沥青是含有大量稠环芳烃的复杂混合物，具有合适的分子间作用力，与石油沥青相比，芳香度高、碳收率大，因此煤焦油沥青是合成高品质针状焦的理想原料。作为煤系针状焦的制备方法，通常是将煤沥青经预处理后，进行延迟焦化并高温煅烧，最后得到煤系针状焦。作为煤系针状焦，可列举出新日化焦、三菱焦、鞍山焦等。
虽然机理尚不明确，但本申请人意外地发现通过选择以含有一定含量的挥发分的煤系针状焦为前驱体，通过密闭热处理，挥发分会逸出并富集到前驱体表面，使得前驱体表面得到均匀包覆，即石墨化前的自包覆。石墨化后，得到的改性石墨具有包覆层。图1为制得的改性石墨的扫描电镜图，图中的改性石墨的具有光滑平整的颗粒表面，证明了包覆层有效降低了改性石墨的表面粗糙度，修复了改性石墨的表面缺陷，减少改性石墨表面与电解液之间的副反应，达到了提高其首次库仑效率的目的。
在一些实施方式中，所述煤系针状焦满足：以质量百分数计，挥发分含量：5～9％，可选地，含量为6～8％；硫含量为小于等于0.2％，可选地，含量小于等于0.1％；灰分含量小于等于0.2％，可选地含量小于等于0.1％；喹啉不溶物含量小于等于0.2％，可选地含量小于等于0.1％；真密度为1.35～1.48g/cm 3，可选地1.39～1.45g/cm 3。煤系针状焦作为前驱体，自身所含有的挥发组分就可作为包覆剂，不需额外添加包覆剂，便能在其表面形成包覆层，从而修饰了颗粒表面的缺陷，降低了颗粒表面的粗糙度。经包覆层修饰后的改性石墨，减少了对活性锂离子的消耗，首次库伦效率因此而提高。同时，前驱体的真密度对制得的改性石墨的振实密度具有一定影响。因此，选取真密度在上述范围内的煤系针状焦作为前驱体，制得的改性石墨也具有较佳的振实密度，进而能提高使用该改性石墨的二次电池的能量密度。
在一些实施方式中，所述热处理步骤中，所述热处理温度为400～800℃，可选地500～700℃；所述恒温时间为2～8小时，可选地3～6小时。热处理温度和恒温时间对于形成改性石墨的包覆层至关重要。通过热处理温度在上述范围内，则能够避免以下情况：若热处理温度过低、恒温时间过短，则可能煤系针状焦中的挥发分无法充分熔融、溢出，在颗粒表面形成包覆层，因此，可能失去了修饰颗粒表面缺陷的作用；若热处理温度过高、恒温时间过长，则可能会造成生产过程中的能耗过高，增加生产成本，造成不必要的浪费。也就是 说，在上述范围内的热处理温度和恒温时间，能够让煤系针状焦中的挥发分溢出并充分熔融，在颗粒表面形成均匀的包覆层，减少对活性锂离子的消耗进而提高首次库仑效率；同时，不额外增添因为高能耗而带来的生产成本。
在一些实施方式中，所述热处理步骤中，所述升温速率为1～15℃/min，可选地，5～12℃/min。所述热处理在上述范围内，则能够避免以下情况：升温速率过快，可能煤系针状焦的挥发分会在到达热处理温度时，短时间内快速溢出，挥发分不能均匀的包裹颗粒表面，同时会造成颗粒团聚。也就是说，在上述范围内的升温速率，煤系针状焦能够均匀受热、匀速升温，挥发分能均匀缓慢地附着于颗粒表面，形成包覆层，相应制得的改性石墨也具有高首次库伦效率进而良好的循环性能。
在一些实施方式中，所述石墨化步骤中，所述石墨化温度为2500～3200℃；所述石墨化保温时间为55～65小时。在上述范围内的石墨化温度和石墨化保温时间，使得经由该方法制备的改性石墨具有良好的石墨化度，良好的层间距方便锂离子的嵌入、脱出，进而提高了改性石墨的首次库仑效率及循环性能。
在一些实施方式中，所述热处理步骤中，所述物料B需满足Dv50＝5～12μm，可选地，8～11μm；且,5μm≥Dn10≥1.5μm，可选地5μm≥Dn10≥2.0μm。通过选取具有上述粒径大小的物料B，方便后续工艺的处理，得到的改性石墨振实密度高、电化学性能优良。
在一些实施方式中，所述破碎步骤中，所述物料A：Dv50＝3～12μm，可选地，Dv50＝6～9μm。将原料破碎至上述的粒径大小，保证了在对原料进行热处理和石墨化时，原料受热均匀充分、颗粒大小分布均匀，制得的改性石墨颗粒大小分布均匀、包覆层完整、石墨化度高，进而改性石墨作为负极材料使用时，首次库伦效率高，循环性能好。
另外，所述煤系针状焦的挥发分含量可以采用本领域已知的方法测试。例如参照YB/T5189-2007进行测定。
所述煤系针状焦的硫含量可以采用本领域已知的方法测试，例如参考GB/T 2286-2008进行测定。
所述煤系针状焦的灰分含量可以采用本领域已知的方法测试，例如参考GB/T 1429-2009进行测定。
所述喹啉不溶物是指煤系针状焦中不溶于喹啉的组分，所述煤系针状焦的喹啉不溶物含量可以采用本领域已知的方法测试，例如参考GB/T2293-97进行测定。
所述平均体积分布粒径Dv50是指，所述改性石墨累计体积分布百分数达到50％时所对应的粒径。在本发明中，改性石墨的体积平均粒径Dv50可采用激光衍射粒度分析法测定。例如参照标准GB/T 19077-2016，使用激光粒度分析仪(例如Malvern Master Size 3000)进行测定。
所述改性石墨的比表面积(BET)测试，可使用比表面积分析仪，根据《气体吸附BET法测定固态物质比表面积》GB/T 19587-2017/ISO9277:2010测试样品比表面积。
所述改性石墨的石墨化度测试可使用X射线衍射仪，根据《人造石墨的点阵参数测定方法》JB/T 4220-2011测试样品石墨化度，石墨化度g＝(3.440-d002)/(3.440-3.354)。
所述改性石墨的真密度可使用振实密度测试仪，根据《金属粉末振实密度的测定》GB/T 5162-2006测试样品振实密度。
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
[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至少一个表面的正极膜层，所述正极膜层包括正极材料。
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，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
本申请的二次电池中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于 高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、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。
本申请的二次电池中，正极材料可采用本领域公知的用于电池的正极材料。作为示例，正极材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极材料的传统材料。这些正极材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
本申请的二次电池中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
本申请的二次电池中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、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至少一种。
本申请的二次电池中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括本申请第二方面的改性石墨。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
本申请的二次电池中，所述负极集流体可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。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(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。
本申请的二次电池中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(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。
本申请的二次电池中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、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至少一种。
本申请的二次电池中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
本申请的二次电池中，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，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
采用电解液的二次电池、以及一些采用固态电解质的二次电池中，还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，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。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
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。例如，图3是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图4，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，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一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图5是作为一个示例的电池模块4。参照图5，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外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述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为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图6和图7是作为一个示例的电池包1。参照图6和图7，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。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(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、储能系统等，但不限于此。
作为所述用电装置，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8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。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该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
使用LHJ型机械粉碎机(制造商：潍坊正远粉体工程设备有限公司)对煤系针状焦原料进行破碎。其中，所述煤系针状焦中的硫含量为0.08％、灰分含量为0.05％、挥发分含量为5.1％、真密度为1.42g/cm 3。将所述煤系针状焦破碎至Dv50＝6～9μm，而后进行分级处理，以方便后续调控所得颗粒产物的粒径分布。采用LHV型整形机(制造商：潍坊正远粉体工程设备有限公司)对破碎后的煤系针状焦进行整形，主机频率为8Hz，并去细粉，处理至Dv50＝9.8μm。将整形后的物料置于WHR型卧式加热反应釜(制造商：无锡庆鑫粉体设备有限公司)中进行热处理，10℃/min加热到600℃恒温4小时。将热处理所得产物加入到石墨化炉中，升温至3000℃保温60小时进行高温石墨化得到人造石墨。由此制备出的改性石墨Dv50＝9.0μm，Dv10＝5.4μm,BET＝1.34m 2/g，石墨化度＝95.3％，振实密度为1.21g/cm 3。
实施例2
除了将热处理温度调整为500℃、整形处理后颗粒Dv50＝11.4μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝10.5μm，Dv10＝5.3μm，BET＝1.35m 2/g,石墨化度＝95.1％，振实密度为1.18g/cm 3。
实施例3
除了将热处理温度调整为400℃、整形处理后颗粒Dv50＝10.3μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.7μm，Dv10＝5.8μm，BET＝1.37m 2/g，石墨化度＝95.0％，振实密度为1.17g/cm 3。
实施例4
除了将热处理温度调整为800℃、整形处理后颗粒Dv50＝10.0μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.5μm，Dv10＝6.1μm，BET＝1.38m 2/g，石墨化度＝95.2％，振实密度为1.20g/cm 3。
实施例5
除了将热处理时间调整为6小时外、整形处理后颗粒Dv50＝10.8μm，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝10.2μm，Dv10＝5.4μm，BET＝1.33m 2/g，石墨化度＝95.3％，振实密度为1.18g/cm 3。
实施例6
除了将热处理时间调整为2小时、整形处理后颗粒Dv50＝9.4μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝8.8μm，Dv10＝5.1μm，BET＝1.35m 2/g,石墨化度＝95.2％，振实密度为1.19g/cm 3。
实施例7
除了将热处理时间调整为8小时外、整形处理后颗粒Dv50＝9.7μm，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.1μm，Dv10＝5.5μm，BET＝1.36m 2/g，石墨化度＝95.3％，振实密度为1.17g/cm 3。
实施例8
除了将煤系针状焦的挥发分含量调整为6.4％、硫含量为0.06％、灰分含量为0.03％、喹啉不溶物含量为0.07％、真密度为1.43g/cm 3、整形处理后颗粒Dv50＝10.1μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.5μm，Dv10＝5.1μm，BET＝1.31m 2/g，石墨化度＝95.1％，振实密度为1.23g/cm 3。
实施例9
除了将挥发分含量调整为6.8％、硫含量为0.07％、灰分含量为0.04％、喹啉不溶物含量为0.03％、真密度为1.36g/cm 3、整形处理后颗粒Dv50＝10.5μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝10.1μm，Dv10＝5.3μm,BET＝1.33m 2/g，石墨化度＝95.0％，振实密度为1.21g/cm 3。
实施例10
除了将挥发分含量调整为7.5％、硫含量为0.06％、灰分含量为0.07％、喹啉不溶物含量为0.04％、真密度为1.48g/cm 3、整形处理后颗粒Dv50＝9.7μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.5μm，Dv10＝5.1μm,BET＝1.31m 2/g，石墨化度＝95.1％，振实密度为1.25g/cm 3。
对比例1
使用LHJ型机械粉碎机(制造商：潍坊正远粉体工程设备有限公司)对煤系针状焦原料进行破碎。其中，煤系针状焦中的硫含量为0.08％、灰分含量为0.05％、挥发分含量为1.2％、喹啉不溶物含量为0.04％、真密度为1.4g/cm 3。将煤系针状焦破碎至Dv50＝6～9μm，而后进行分级处理，以方便后续调控所得颗粒产物的粒径分布。采用LHV型整形机(制造商：潍坊正远粉体工程设备有限公司)对破碎后的煤系针状焦进行整形，主机频率为8Hz，并去细粉处理至Dv50＝10.7μm。将整形后的物料置于WHR型卧式加热反应釜(制造商：无锡庆鑫粉体设备有限公司)中进行热处理，10℃/min加热到600℃恒温4小时。将热处理所得产物加入到石墨化炉中，升温至3000℃保温60小时进行高温石墨化得到人造石墨。由此制备出的改性石墨Dv50＝9.2μm，Dv10＝5.6μm，BET＝1.57m 2/g，石墨化度＝95.2％，振实密度为1.13g/cm 3。
对比例2
除了将原料换为普通石油焦，挥发分含量调整为10％、硫含量为0.21％、灰分含量为0.07％、不含喹啉不溶物、真密度为1.45g/cm 3、整形处理后颗粒Dv50＝10.2μm外，其他条件与对比例1相同，由此制备出的改性石墨Dv50＝16.5μm，Dv10＝6.8μm，BET＝1.52m 2/g，石墨化度＝93.1％，振实密度1.09g/cm 3。
对比例3
除了取消对煤系针状焦热处理这一步骤、整形处理后颗粒Dv50＝9.7μm之外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.0μm，Dv10＝5.4μm,BET＝1.61m 2/g，石墨化度＝95.0％，振实密度为1.17g/cm 3。
对比例4
除了将原料换为普通石油焦，挥发分含量调整为0.9％、硫含量为0.30％、灰分含量为0.15％、真密度为1.44g/cm 3，取消热处理这一步骤、整形处理后 颗粒Dv50＝10.7μm之外，其他条件与对比例2相同，由此制备出的改性石墨Dv50＝10.3μm，Dv10＝6.0μm，BET＝1.49m 2/g，石墨化度＝94.0％，振实密度为1.26g/cm 3。
对比例5
除了将热处理温度调整为200℃、热处理时间为1小时、整形处理后颗粒Dv50＝9.5μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝8.9μm，Dv10＝5.2μm，BET＝1.53m 2/g，石墨化度＝95.2％，振实密度为1.03g/cm 3。
对比例6
除了将热处理时间调整为1小时、整形处理后颗粒Dv50＝9.5μm外，其他条件与实施例1相同，由此制备出的改性石墨Dv50＝9.0μm，Dv10＝5.1μm，BET＝1.51m 2/g，石墨化度＝95.0％，振实密度为1.24g/cm 3。
上述实施例1～10、对比例1～6的改性石墨的相关制备参数如下述表1所示。
表1：实施例1～10与对比例1～6改性石墨制备参数
Figure PCTCN2021115840-appb-000001
Figure PCTCN2021115840-appb-000002
上述实施例1～10和对比例1～6中得到的改性石墨分别进行平均体积粒径分布测试、BET测试、石墨化度测试、振实密度测试。测试结果如下表2所示。
表2：实施例1～10与对比例1～6改性石墨的平均体积粒径分布、BET、石墨化度、振实密度的测试结果
  Dv50[μm] Dv10[μm] BET[m 2/g] 石墨化度[％] 振实密度[g/cm 3]
实施例1 9.0 5.4 1.34 95.3 1.21
实施例2 10.5 5.3 1.35 95.1 1.18
实施例3 9.7 5.8 1.37 95.0 1.17
实施例4 9.5 6.1 1.38 95.2 1.20
实施例5 10.2 5.4 1.33 95.3 1.18
实施例6 8.8 5.1 1.35 95.2 1.19
实施例7 9.1 5.5 1.36 95.3 1.18
实施例8 9.5 5.1 1.31 95.1 1.23
实施例9 10.1 5.3 1.33 95.0 1.21
实施例10 9.2 5.6 1.35 95.3 1.25
对比例1 10.1 5.7 1.57 95.2 1.13
对比例2 16.5 6.8 1.52 93.1 1.09
对比例3 9.0 5.4 1.61 95.0 1.17
对比例4 10.3 6.0 1.49 94.0 1.26
对比例5 8.9 5.2 1.53 95.2 1.03
对比例6 9.0 5.1 1.56 95.0 1.24
另外，将上述实施例1～10和对比例1～6中得到的改性石墨分别如下所示制备成扣式电池和二次电池，进行电化学性能测试。测试结果如下表3所示。
(1)扣式电池的制备
将上述各实施例和对比例中的改性石墨、导电剂Super P、粘结剂(PVDF)按91.6:1.8:6.6的质量比与溶剂NMP(N-甲基吡咯烷酮)混合均匀，制成浆料；将制备好的浆料涂覆于铜箔集流体上，于烘箱中干燥后冷压备用，压密范围：1.4～1.6g/cm 3；以金属锂片为对电极；采用聚乙烯(PE)薄膜做为隔离膜；将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按体积比1:1:1混合，然后将LiPF 6均匀溶解在上述溶液中得到电解液，其中LiPF 6的浓度为1mol/L；在氩气保护的手套箱中将上述各部分组装成CR2430型扣式电池。
(2)扣电初始克容量、首次库仑效率测试
将所得扣式电池静置12小时后，使用LAND CT2001A以0.05C的电流进行恒流放电至0.005V，静置10分钟，以50μA的电流再进行恒流放电至0.005V，静置10分钟，以10μA的电流再进行恒流放电至0.005V，三次放电容量之和为放电容量c 0；然后以0.1C的电流进行恒流充电至2.000V，记录充电容量c。所制备负极材料的克容量＝充电容量c/负极材料质量m，首次库仑效率＝(充电容量c/放电容量c 0)*100％。
(3)二次电池的制备
将上述各实施例和对比例中的改性石墨作为负极活性物质，与导电剂乙炔黑、粘结剂丁苯橡胶(SBR)以及增稠剂碳甲基纤维素钠(CMC)按照重量比90：5：2：2：1在去离子水溶剂体系中充分搅拌混合均匀后，涂覆于铜箔上烘干、冷压，得到负极极片。
将正极物质与导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比94：3：3在N-甲基吡咯烷酮溶剂体系中充分搅拌混合均匀后，涂覆于铝箔上烘干、冷压，得到正极极片。
以聚乙烯(PE)制多孔聚合薄膜作为隔离膜。
将正极片、隔离膜以及负极片按顺序重叠，使隔离膜处于正负极之间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入上述(1)扣式电池制备所使用的电解液并封装，得到二次电池。
(4)二次电池在45℃循环性能测试
将上述制备的各二次电池，首先在25℃下1/3C充电至3.65V(C为电池标称容量)，恒压3.65V充电至0.05C，然后1/3C放电至2.5V并记录放电容量为C 0。电池的循环性能在45℃环境下进行测试，将电池在2.5～3.65V之间以1C 0/1C 0的倍率进行充放电循环，电池第100圈的放电容量C 100，第100圈的循环容量保持率为C 100/C 0。
表3：实施例1～10与对比例1～6的扣电初始克容量及首次库仑效率测试、二次电池45℃下循环性能测试结果
Figure PCTCN2021115840-appb-000003
Figure PCTCN2021115840-appb-000004
根据上述结果可知，实施例1～10中在未额外添加包覆剂的情况下，利用煤系针状焦自身所含的挥发性组分作为包覆剂，制得的改性石墨具有包覆层，因而在改善颗粒表面粗糙度，减少对电解液中活性锂的消耗等方面均取得了良好的效果，制得的改性石墨的电化学性能也因此而提高。如图2所示，图2为本申请实施例1的改性石墨的首次充放电图。实施例1中的改性石墨展现出了优良的电化学性能：首次放电克容量为376.9mAh/g、首次充电克容量为358.1mAh/g,首次库仑效率为95.0％。总体上，实施例1～10中改性石墨的首次库仑效率均大于等于95.0％，45℃下的循环100圈后容量保持率均大于97.0％。
而相对于此，对比例1中，在与实施例1相同的热处理工艺条件下，由于煤系针状焦挥发分含量较低，挥发分无法充分、均匀地包裹在颗粒表面，导致包覆层无法充分改善石墨的界面性能，因而制得的改性石墨首次库仑效率较低。对比例2和对比例4与实施例1～10相比，原料都选用了普通石油焦。对比例2中，普通石油焦热处理过程中产生粘结效应，造成颗粒团聚，未能有效提高制得的改性石墨的首次库仑效率。对比例4中，普通石油焦的挥发分含量较低且取消了对其的热处理工艺，制得的改性石墨不具有包覆层，颗粒表面的缺陷依然存在，因而对减少其对活性锂的消耗及提高其首次库仑效率的效果不佳。
对比例3、对比例5和对比例6与实施例1的区别主要在于热处理温度和热处理时间。对比例3中的取消了对煤系针状焦的热处理，挥发分无法均匀包覆在颗粒表面形成包覆层，因为未能改善制得的改性石墨的界面性能，因而其循环性能和首次库仑效率均不如实施例1～10中改性石墨的性能。对比例5中，热处理温度较低，挥发分无法充分富集到颗粒表面，热处理时间较短，挥发组分无法形成完整的核壳结构进而起到改善颗粒表面的效果。因此，对于石墨的界面性能和电化学性能的提升效果均不佳。对比例6中，对煤系针状焦的热处理时间较短，不能在颗粒表面形成包覆层，从而减少改性石墨与电解液间发生的副反应。因此，对制得的改性石墨的电化学性能和界面性能改善效果有限。
此外，表2中，对比实施例1～10和对比例1～6可以看出，实施例1～10中的改性石墨的BET均小于对比例1～6中的改性石墨的BET。改性石墨作为二次电池的负极材料时，其BET其首次库仑效率有关，例如BET越大，负极材料越易与电解液发生副反应，消耗活性锂，从而影响负极材料的循环性能。因此，实施例1～10中改性石墨相对于对比例1～6中的改性石墨有着较小的BET，意味着实施例1～10中的改性石墨作为负极材料有着更好的首次库仑效率。表3中的数据也充分说了这一点。同时，实施例1～10中的改性石墨相较于对比例1～6中的改性石墨，有着更大的振实密度。具有高振实密度的负极材料也保证了二次电池整体的能量密度。
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. 一种改性石墨的制备方法，其特征在于，
    包括以下步骤：
    破碎步骤：将煤系针状焦破碎，得到物料A；
    整形步骤：将所述物料A进行整形并去细粉，得到物料B；
    热处理步骤：将所述物料B置于反应釜中进行热处理后，冷却至室温，得到物料C；
    石墨化步骤：将所述物料C置于石墨炉中进行石墨化后，冷却至室温，所得产物即为所述改性石墨。
  2. 根据权利要求1所述的改性石墨的制备方法，其特征在于，以质量百分数计，在所述煤系针状焦中，挥发分含量为5～9％，可选为6～8％，硫含量为小于等于0.2％，可选为小于等于0.1％；灰分含量为小于等于0.2％，可选为小于等于0.1％，喹啉不溶物含量小于等于0.2％，可选地含量小于等于0.1％，
    且，所述煤系针状焦的真密度为1.35～1.48g/cm 3，可选为1.39～1.45g/cm 3。
  3. 根据权利要求1或2所述的改性石墨的制备方法，其特征在于，所述热处理步骤中，所述热处理温度为400～800℃，可选地500～700℃；所述热处理时间为2～8小时，可选地3～6小时。
  4. 根据权利要求1～3任一项所述的改性石墨的制备方法，其特征在于，所述热处理步骤中，所述升温速率为1～15℃/min，可选地，5～12℃/min。
  5. 根据权利要求1～4任一项所述的改性石墨的制备方法，其特征在于，所述石墨化步骤中，所述石墨化温度为2500～3200℃；所述石墨化时间为55～65小时。
  6. 根据权利要求1～5任一项所述的改性石墨的制备方法，其特征在于，所述整形步骤中，所述物料B满足：Dv50＝5～12μm，可选地，8～11μm；
    且,5μm≥Dn10≥1.5μm，可选地5μm≥Dn10≥2.0μm。
  7. 根据权利要求1～6任一项所述的改性石墨的制备方法，其特征在于，所述破碎步骤中，所述物料A满足：Dv50＝3～12μm，可选地Dv50＝6～9μm。
  8. 一种改性石墨，其通过上述权利要求1～8中任一项所述的改性石墨的制备方法制备得到。
  9. 一种负极极片，包括负极集流体和设置于负极集流体至少一个表面上的负极材料层，所述负极材料层包含权利要求9所述的改性石墨。
  10. 一种二次电池，其特征在于，包括权利要求10所述的负极极片。
  11. 一种电池模块，其特征在于，包括权利要求11所述的二次电池。
  12. 一种电池包，其特征在于，包括权利要求12所述的电池模块。
  13. 一种用电装置，其特征在于，包括权利要求11所述的二次电池、权利要求12所述的电池模块或权利要求13所述的电池包中的至少一种。
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001023638A (ja) * 1999-07-05 2001-01-26 Sumitomo Metal Ind Ltd リチウムイオン二次電池負極用黒鉛粉末の製造方法
CN106299373A (zh) * 2016-09-20 2017-01-04 新乡市华鑫电源材料有限公司 一种锂离子电池高倍率负极材料及其制备方法
CN107221674A (zh) * 2017-06-16 2017-09-29 安徽科达洁能新材料有限公司 一种锂离子电池复合石墨负极材料及其制备方法
CN107579252A (zh) * 2017-09-07 2018-01-12 福建杉杉科技有限公司 一种高功率炭包覆人造石墨负极材料的制备方法
CN109704323A (zh) * 2017-10-26 2019-05-03 宁德时代新能源科技股份有限公司 一种电极材料及二次电池
CN109704324A (zh) * 2017-10-26 2019-05-03 宁德时代新能源科技股份有限公司 一种电极材料及二次电池
CN110718690A (zh) * 2018-07-12 2020-01-21 宝武炭材料科技有限公司 一种基于针状焦生焦和煅后焦的电池负极材料的制备方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109621893B (zh) * 2018-12-07 2022-05-10 鞍钢化学科技有限公司 一种利用化工含碳废料制备活性焦的方法
CN112812796B (zh) * 2021-01-13 2022-02-11 中国石油大学(华东) 一种生物基针状焦及其制备方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001023638A (ja) * 1999-07-05 2001-01-26 Sumitomo Metal Ind Ltd リチウムイオン二次電池負極用黒鉛粉末の製造方法
CN106299373A (zh) * 2016-09-20 2017-01-04 新乡市华鑫电源材料有限公司 一种锂离子电池高倍率负极材料及其制备方法
CN107221674A (zh) * 2017-06-16 2017-09-29 安徽科达洁能新材料有限公司 一种锂离子电池复合石墨负极材料及其制备方法
CN107579252A (zh) * 2017-09-07 2018-01-12 福建杉杉科技有限公司 一种高功率炭包覆人造石墨负极材料的制备方法
CN109704323A (zh) * 2017-10-26 2019-05-03 宁德时代新能源科技股份有限公司 一种电极材料及二次电池
CN109704324A (zh) * 2017-10-26 2019-05-03 宁德时代新能源科技股份有限公司 一种电极材料及二次电池
CN110718690A (zh) * 2018-07-12 2020-01-21 宝武炭材料科技有限公司 一种基于针状焦生焦和煅后焦的电池负极材料的制备方法

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