WO2024065181A1 - Composition d'électrode négative et son procédé de préparation, suspension d'électrode négative et son procédé de préparation, feuille d'électrode négative et son procédé de préparation, batterie secondaire, dispositif électrique et utilisation d'un composé thianthrène - Google Patents

Composition d'électrode négative et son procédé de préparation, suspension d'électrode négative et son procédé de préparation, feuille d'électrode négative et son procédé de préparation, batterie secondaire, dispositif électrique et utilisation d'un composé thianthrène Download PDF

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WO2024065181A1
WO2024065181A1 PCT/CN2022/121750 CN2022121750W WO2024065181A1 WO 2024065181 A1 WO2024065181 A1 WO 2024065181A1 CN 2022121750 W CN2022121750 W CN 2022121750W WO 2024065181 A1 WO2024065181 A1 WO 2024065181A1
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negative electrode
thianthrene
active
thianthrene compound
compound
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PCT/CN2022/121750
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English (en)
Chinese (zh)
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刘贺洋
吴泽
刘江
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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 PCT/CN2022/121750 priority Critical patent/WO2024065181A1/fr
Publication of WO2024065181A1 publication Critical patent/WO2024065181A1/fr

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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
    • H01M10/052—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
    • 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers

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  • the present application relates to the field of secondary batteries, and specifically to a negative electrode composition and a preparation method thereof, a negative electrode slurry and a preparation method thereof, a negative electrode sheet and a preparation method thereof, a secondary battery, an electrical device, and applications of thianthrene compounds.
  • the negative electrode sheet of a secondary battery often has a certain porosity, which helps the electrolyte to infiltrate the negative electrode sheet to maintain the performance of the secondary battery. Therefore, how to improve the porosity of the negative electrode sheet has an important impact on the performance of the secondary battery.
  • the present application provides a negative electrode composition and preparation method, a negative electrode slurry and preparation method, a negative electrode plate and preparation method, a secondary battery, an electrical device and application of thianthrene compounds.
  • the negative electrode composition can effectively improve the porosity of the negative electrode plate.
  • the first aspect of the present application provides a negative electrode composition.
  • the negative electrode composition comprises a negative electrode active material and a thianthrene compound.
  • the negative electrode composition in the present application includes thianthrene compounds. Introducing thianthrene compounds into the negative electrode composition provides a new idea for improving the porosity of the negative electrode plate, which can improve the porosity of the negative electrode plate, thereby improving the wettability of the electrolyte in the battery to the negative electrode plate and improving the performance of the battery.
  • the thianthrene compound has a structure as shown in formula (I):
  • R1 and R2 are independently selected from H, D, F, Cl, Br, I, an alkyl group having 1 to 10 carbon atoms, and an acyl group having 1 to 10 carbon atoms.
  • the thianthrene compound includes one or more of thianthrene, 2-acetylthianthrene, 2,7-diacetylthianthrene, 2,7-dibromothianthrene and 2,7-diisobutyrylthianthrene.
  • the melting point of the thianthrene compound at standard atmospheric pressure is greater than 100°C.
  • the mass percentage of the thianthrene compound is ⁇ 5% based on the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound is 1% to 5% based on the mass percentage of the negative electrode active material.
  • the D50 of the thianthrene compound is 0.5 ⁇ m to 5 ⁇ m.
  • the second aspect of the present application provides a method for preparing the negative electrode composition of the first aspect, comprising the following steps: mixing the negative electrode active material and the thianthrene compound.
  • the third aspect of the present application provides a negative electrode slurry, comprising a solvent and the negative electrode composition described in the first aspect.
  • the fourth aspect of the present application provides a method for preparing the negative electrode slurry according to the second aspect, comprising the following steps:
  • the solvent and the negative electrode composition are mixed.
  • a fifth aspect of the present application provides a negative electrode sheet, comprising:
  • a negative electrode active layer is disposed on at least one surface of the negative electrode current collector, and the negative electrode active layer comprises the negative electrode composition of the first aspect.
  • the negative electrode active layer is divided into a first active sublayer and a second active sublayer which are stacked, the first active sublayer is located on at least one surface of the negative electrode current collector, and the second active sublayer is located on the first active sublayer; the negative electrode composition is located in the second active sublayer.
  • the mass percentage of the thianthrene compound is ⁇ 5% based on the mass percentage of the active material of the second active sub-layer.
  • the mass percentage of the thianthrene compound is 1% to 5% based on the mass percentage of the active material of the second active sub-layer.
  • the sixth aspect of the present application provides a method for preparing the negative electrode sheet according to the fifth aspect, comprising the following steps:
  • the negative electrode active layer is formed on at least one surface of the negative electrode current collector using the negative electrode slurry described in the third aspect.
  • the negative electrode active layer is divided into a first active sublayer and a second active sublayer which are stacked, the first active sublayer is formed on at least one surface of the current collector, and the second active sublayer is formed on the first active sublayer using the negative electrode slurry.
  • the seventh aspect of the present application provides an application of a thianthrene compound as a pore former in a negative electrode slurry or a negative electrode sheet.
  • the thianthrene compound has a structure as shown in formula (I):
  • R1 and R2 are independently selected from H, D, F, Cl, Br, I, an alkyl group having 1 to 10 carbon atoms, and an acyl group having 1 to 10 carbon atoms.
  • the thianthrene compound includes one or more of thianthrene, 2-acetylthianthrene, 2,7-diacetylthianthrene, 2,7-dibromothianthrene and 2,7-diisobutyrylthianthrene.
  • the melting point of the thianthrene compound at standard atmospheric pressure is greater than 100°C.
  • the present application provides a secondary battery, comprising the negative electrode sheet described in the fourth aspect.
  • the solvent of the electrolyte includes one or both of dimethyl carbonate and diethyl carbonate.
  • a ninth aspect of the present application provides an electrical device, comprising the secondary battery described in the eighth aspect.
  • FIG. 1 is a schematic diagram of a secondary battery according to an 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 shown in FIG. 4 according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of an electrical device using a secondary battery as a power source according to an embodiment of the present application.
  • range disclosed in this application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range.
  • the range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that the range of 60 to 110 and 80 to 120 is also expected.
  • the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers.
  • the numerical range "0 to 5" means that all real numbers between "0 to 5" have been fully listed in this article, and "0 to 5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the “include” and “comprising” mentioned in this application are open-ended or closed-ended.
  • the “include” and “comprising” may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A or B”: 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 present application provides a negative electrode composition.
  • the negative electrode composition includes a negative electrode active material and a thianthrene compound. Introducing the thianthrene compound into the negative electrode composition provides a new idea for improving the porosity of the negative electrode sheet, which can improve the porosity of the negative electrode sheet, thereby improving the wettability of the electrolyte in the battery to the negative electrode sheet and improving the performance of the battery.
  • the negative electrode composition includes a pore former, and the pore former includes a thianthrene compound.
  • the thianthrene compound is used as a pore former in the negative electrode composition.
  • the traditional way to improve the porosity of the negative electrode sheet is to add a pore former to the negative electrode slurry, then coat the negative electrode slurry on the current collector, and then dry it.
  • the pore former volatilizes or decomposes, leaving pores in the negative electrode active layer, thereby achieving the effect of improving the porosity of the negative electrode sheet.
  • this porosity improvement method is prone to pore former residues, which in turn has an adverse effect on the performance of the battery.
  • the negative electrode composition can be added to the negative electrode slurry or the negative electrode active layer, so that after the negative electrode active layer is formed, the thianthrene compound is preserved in the negative electrode active layer, and then when the negative electrode sheet is in contact with the electrolyte, the thianthrene compound gradually dissolves in the electrolyte, thereby leaving pores in the negative electrode active layer, thereby achieving the effect of improving the porosity of the negative electrode sheet.
  • the thianthrene compound can be continuously dissolved in the electrolyte. Compared with the traditional method of removing the pore former by drying, the residual probability and residual amount of the pore former will be greatly reduced, thereby effectively avoiding the adverse effects of the residual pore former on battery performance.
  • the volatilization or decomposition speed of the pore former at different positions in the negative electrode active layer is different.
  • the outer layer of the negative electrode active layer may be heated more obviously than the inner layer, which will cause the outer layer of the negative electrode active layer to be heated faster than the inner layer.
  • the problem of uneven heating of the pore former in the outer layer and the pore former in the inner layer of the negative electrode active layer is likely to occur.
  • the pore former in the outer layer is heated faster than the inner layer, which will cause the pore former in the outer layer to decompose or volatilize faster than the pore former in the inner layer, resulting in uneven pores in the negative electrode active layer.
  • the thianthrene compound can be slowly dissolved in the electrolyte, and the dissolution rate of the thianthrene compound in the outer layer of the negative electrode active layer is comparable to that of the thianthrene compound in the inner layer, which can improve the uniformity of the pores of the negative electrode sheet.
  • the flow direction and flow mode of the gas generated by the volatilization or decomposition of the pore-forming agent are difficult to control, which can easily cause impact on the surface of the negative electrode plate, causing the surface of the negative electrode plate to be uneven, and adversely affecting the surface morphology of the negative electrode plate.
  • the thianthrene compound slowly dissolves with the electrolyte, which can effectively avoid the impact of the pore-forming process on the surface of the negative electrode plate, avoid adversely affecting the surface morphology of the negative electrode plate, and help maintain the surface flatness of the negative electrode plate, thereby improving the performance of the battery.
  • the dissolved thianthrene compound in the method of improving the porosity of the negative electrode sheet of the present application, can be used as an anti-overcharge additive to avoid the continuous increase of the battery voltage when overcharging occurs, thereby further improving the performance of the battery.
  • the thianthrene compound has a structure as shown in formula (I):
  • R1 and R2 are independently selected from H, D, F, Cl, Br, I, an alkyl group having 1 to 10 carbon atoms, and an acyl group having 1 to 10 carbon atoms.
  • alkyl group can be a straight chain alkyl group or a branched chain alkyl group, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, etc.
  • the acyl group can be a straight chain acyl group or a branched chain acyl group, such as formyl, acetyl, propionyl, butyryl, isopropionyl, isobutyryl, etc.
  • the thianthrene compound includes one or more of thianthrene, 2-acetylthianthrene, 2,7-diacetylthianthrene, 2,7-dibromothianthrene, and 2,7-diisobutyrylthianthrene.
  • thianthrene, 2-acetylthianthrene, 2,7-diacetylthianthrene, 2,7-dibromothianthrene and 2,7-diisobutyrylthianthrene have the following structural formulas, respectively:
  • the melting point of the thianthrene compound at standard atmospheric pressure is greater than 100° C.
  • the mass percentage of the thianthrene compound is ⁇ 5% in terms of the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound within this range can better balance the improvement of porosity and battery capacity.
  • the mass percentage of the thianthrene compound is too large, the amount of negative electrode active material may be reduced, resulting in a decrease in battery capacity.
  • the mass percentage of the thianthrene compound is ⁇ 1 in terms of the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5% in terms of the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound in terms of the mass percentage of the negative electrode active material can also be selected in other suitable ranges within the range of 1% to 5%. When the mass percentage of the thianthrene compound is too large, the bonding of the negative electrode sheet may also be reduced.
  • the D50 of the thianthrene compound is 0.5 ⁇ m to 5 ⁇ m.
  • the D50 of the thianthrene compound can be, but is not limited to, 0.8 ⁇ m, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, 3.5 ⁇ m, 4 ⁇ m, 4.5 ⁇ m, etc. It is understood that the D50 of the thianthrene compound can also be other suitable selections within the range of 0.5 ⁇ m to 5 ⁇ m.
  • the present application also provides a method for preparing the above negative electrode composition, which comprises the following steps: mixing the active material and the thianthrene compound.
  • the present application also provides a negative electrode slurry.
  • the negative electrode slurry includes a solvent and the above-mentioned negative electrode composition.
  • the negative electrode slurry includes the above-mentioned negative electrode composition.
  • the negative electrode slurry further includes a binder.
  • the present application also provides a method for preparing the above-mentioned negative electrode slurry, comprising the following steps: mixing a solvent and a negative electrode composition.
  • the present application also provides a negative electrode plate, which includes a negative electrode current collector and a negative electrode active layer, wherein the negative electrode active layer is disposed on at least one surface of the negative electrode current collector, and the negative electrode active layer includes the negative electrode composition.
  • the mass percentage of the thianthrene compound is ⁇ 5% based on the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound can better balance the improvement of porosity and battery capacity within this range.
  • the mass percentage of the thianthrene compound is too large, the amount of the negative electrode active material may be reduced, resulting in a decrease in battery capacity.
  • the mass percentage of the thianthrene compound is ⁇ 1 based on the mass percentage of the negative electrode active material.
  • the mass percentage of the thianthrene compound is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5% based on the mass percentage of the negative electrode active material. It is understandable that the mass percentage of the thianthrene compound can also be selected in the range of 1% to 5% based on the mass percentage of the negative electrode active material.
  • the D50 of the thianthrene compound is 0.5 ⁇ m to 5 ⁇ m.
  • the D50 of the thianthrene compound can be, but is not limited to, 0.8 ⁇ m, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, 3.5 ⁇ m, 4 ⁇ m, 4.5 ⁇ m, etc. It is understood that the D50 of the thianthrene compound can also be other suitable selections within the range of 0.5 ⁇ m to 5 ⁇ m.
  • the negative electrode active layer is divided into a first active sublayer and a second active sublayer which are stacked, the first active sublayer is located on at least one surface of the negative electrode current collector, and the second active sublayer is located on the first active sublayer; the negative electrode composition is located in the second active sublayer.
  • the active material of the first active sublayer and the active material of the second active sublayer may be the same or different.
  • the active material of the first active sublayer includes an energy-type active material
  • the active material of the second active sublayer includes a power-type active material.
  • the active material of the first active sublayer is energy-type graphite
  • the active material of the second active sublayer is fast-charging graphite.
  • the mass percentage of the thianthrene compound is ⁇ 5% based on the mass percentage of the active material in the second active sublayer.
  • the mass percentage of the thianthrene compound within this range can better balance the improvement of porosity and battery capacity.
  • the mass percentage of the thianthrene compound is ⁇ 1 based on the mass percentage of the active material in the second active sublayer.
  • the mass percentage of the thianthrene compound is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5% based on the mass percentage of the active material in the second active sublayer. It is understandable that the mass percentage of the thianthrene compound can also be selected in the range of 1% to 5% based on the mass percentage of the active material in the second active sublayer.
  • the present application also provides a method for preparing the above-mentioned negative electrode sheet, comprising the following steps: forming the negative electrode active layer on at least one surface of the negative electrode current collector using the above-mentioned negative electrode slurry.
  • the negative electrode active layer is divided into a first active sublayer and a second active sublayer which are stacked, the first active sublayer is formed on at least one surface of the current collector, and the second active sublayer is formed on the first active sublayer using the above negative electrode slurry.
  • forming the first active sublayer on at least one surface of the current collector is forming the first active sublayer by slurry.
  • the slurry for forming the first active sublayer does not contain the negative electrode composition.
  • the present application also provides an application of a thianthrene compound as a pore former in a negative electrode slurry or a negative electrode sheet.
  • the thianthrene compound includes one or more of thianthrene, 2-acetylthianthrene, 2,7-diacetylthianthrene, 2,7-dibromothianthrene and 2,7-diisobutyrylthianthrene.
  • the melting point of the thianthrene compound at standard atmospheric pressure is greater than 100°C.
  • the present application also provides a secondary battery, comprising the above-mentioned negative electrode plate and an electrolyte, wherein the negative electrode active layer of the negative electrode plate is in contact with the electrolyte.
  • the secondary battery is suitable for various electrical devices using batteries, such as mobile phones, portable devices, laptop computers, battery cars, electric toys, electric tools, electric cars, ships and spacecraft, etc.
  • the spacecraft includes airplanes, rockets, space shuttles and spacecrafts, etc.
  • thianthrene compounds have good solubility in electrolyte.
  • the solvent of the electrolyte includes one or both of dimethyl carbonate and diethyl carbonate.
  • the present application also provides an electrical device, comprising the above-mentioned secondary battery.
  • a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil may 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 may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may include a positive electrode active material for a battery known in the art.
  • the positive electrode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active 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 oxide (such as LiCoO2 ), lithium nickel oxide (such as LiNiO2 ), lithium manganese oxide (such as LiMnO2 , LiMn2O4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also referred to as NCM333 ), LiNi0.5Co0.2Mn0.3O2 (also referred to as NCM523 ) , LiNi0.5Co0.25Mn0.25O2 (also referred to as NCM211 ) , LiNi0.6Co0.2Mn0.2O2 (also referred to as NCM622 ), LiNi0.8Co0.1Mn0.1O2 (also referred to as NCM811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • the weight ratio of the positive electrode active material in the positive electrode film layer is 80 to 100 weight %, based on the total weight of the positive electrode film layer.
  • the positive electrode film layer may also optionally include a binder.
  • the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • the weight ratio of the binder in the positive electrode film layer is 0 to 20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode film layer may further 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 weight ratio of the conductive agent in the positive electrode film layer is 0 to 20 weight %, based on the total weight of the positive electrode film layer.
  • the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry, wherein the positive electrode slurry has a solid content of 40 to 80 wt%, and the viscosity at room temperature is adjusted to 5000 to 25000 mPa ⁇ s, the positive electrode slurry is coated on the surface of the positive current collector, and after drying, the positive electrode sheet is formed after cold pressing by a cold rolling mill; the positive electrode powder coating unit area density is 150-350 mg/m 2 , and the positive electrode sheet compaction density is 3.0-3.6 g/cm 3 , and can be optionally 3.3-3.5 g/cm 3 .
  • the positive electrode sheet in the embodiment of the present application can be made by using the above-mentioned positive electrode sheet as the positive electrode sheet body and forming a solid electrolyte interface film on the surface of the positive electrode sheet body.
  • 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, wherein the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil may be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate.
  • the composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • 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 and lithium titanate.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries can also be used. These negative electrode active materials can be used alone or in combination of two or more.
  • the weight ratio of the negative electrode active material in the negative electrode film layer is 70 to 100 weight%, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • PAAS sodium polyacrylate
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • PMAA polymethacrylic acid
  • CMCS carboxymethyl chitosan
  • the negative electrode film layer may further include a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the weight ratio of the conductive agent in the negative electrode film layer is 0 to 20 weight %, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer may further include other additives, such as a thickener (such as sodium carboxymethyl cellulose (CMC-Na)), etc.
  • a thickener such as sodium carboxymethyl cellulose (CMC-Na)
  • the weight ratio of the other additives in the negative electrode film layer is 0 to 15 weight %, based on the total weight of the negative electrode film layer.
  • the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity at room temperature is adjusted to 2000-10000mPa ⁇ s; the obtained negative electrode slurry is coated on the negative electrode collector, and after a drying process, cold pressing such as rolling, a negative electrode sheet is obtained.
  • the negative electrode powder coating unit area density is 75-220mg/ m2
  • the negative electrode sheet compaction density is 1.2-2.0g/ m3 .
  • the negative electrode sheet in the embodiment of the present application can be made by using the above-mentioned negative electrode sheet as the negative electrode sheet body and forming a solid electrolyte interface film on the surface of the negative electrode sheet body.
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.
  • the electrolyte can be liquid, gel or all-solid.
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from one or more of lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorobis(oxalatophosphate) (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).
  • concentration of the electrolyte salt is generally 0.5 to
  • the solvent can be selected from one or more of fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS) and diethyl sulfone (FEC),
  • the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the secondary battery further includes a separator.
  • the present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation.
  • the materials of each layer can be the same or different, without particular limitation.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.
  • the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery can also be a soft package, such as a bag-type soft package.
  • the material of the soft package can be plastic, and as plastic, polypropylene, polybutylene terephthalate, and polybutylene succinate can be listed.
  • the present application has no particular restrictions on the shape of the secondary battery, which can be cylindrical, square, or other arbitrary shapes.
  • FIG. 1 is a secondary battery 5 of a square structure as an example.
  • the outer package may include a shell 51 and a cover plate 53.
  • the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is encapsulated in the receiving cavity.
  • the 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.
  • secondary batteries may be assembled into a battery module.
  • the number of secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG3 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. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may further include a housing having a housing space, and the plurality of secondary batteries 5 are housed in the housing space.
  • the battery modules described above may also be assembled into a battery pack.
  • the battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.
  • FIG4 and FIG5 are battery packs 1 as an example.
  • 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, and the upper box body 2 can be covered on the lower box body 3 to form a closed space for accommodating the battery modules 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical 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 for the electrical device, and can also be used as an energy storage unit for the electrical device.
  • the electrical device may include mobile devices (such as mobile phones, laptops, 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., but are not limited thereto.
  • a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.
  • Fig. 6 is an example of an electric device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • a battery pack or a battery module may be used.
  • a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.
  • CMC and deionized water were stirred for 3 hours under the condition of vacuum degree less than -0.08MPa to obtain CMC aqueous solution, and then carbon black, SBR, graphite, and thionyl compounds were added to the CMC aqueous solution, and fully stirred for 7 hours under the condition of vacuum degree less than -0.08MPa to obtain negative electrode slurry.
  • the negative electrode slurry obtained in (1) is evenly coated on the surface of a copper foil with a thickness of 12 ⁇ m, and then dried at 95°C to obtain a negative electrode pre-finished product.
  • LiFePO 4 lithium iron phosphate
  • CB conductive carbon black
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the negative electrode sheet, positive electrode sheet and 25 ⁇ m thick polypropylene film separator prepared in the above steps (2) and (3) are stacked in the order of positive electrode sheet, separator and negative electrode sheet, and then wound to make the electrode core of the lithium ion battery.
  • the electrode core is placed in a steel square lithium ion battery shell with a height of 50 mm, a thickness of 5 mm and a width of 34 mm, and then 3.8 g of electrolyte is injected, and finally the battery shell is sealed to make a 053450 lithium ion battery.
  • the electrolyte is a LiPF 6 /EC+DEC+EMC+DMC system.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 1 part.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 2 parts.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 4 parts.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 5 parts.
  • the difference of this embodiment is that the negative electrode active layer is divided into a first active sublayer and a second active sublayer which are stacked, the first active sublayer is located on at least one surface of the negative electrode current collector, and the second active sublayer is located on the first active sublayer.
  • the difference between the active slurry of the first active sublayer and step (1) in Example 1 is that the negative electrode slurry does not contain thianthrene compounds, and the active slurry of the second active sublayer is the negative electrode slurry obtained in step (1) in Example 1.
  • the preparation method of the negative electrode sheet in this embodiment is: the first active layer negative electrode slurry prepared above is evenly coated on the surface of a copper foil with a thickness of 12 ⁇ m, and then the second active layer negative electrode slurry prepared above is evenly coated on the first active layer negative electrode, and then the water is dried at 95°C to obtain a pre-finished negative electrode sheet.
  • the difference of this example is that in the negative electrode slurry, the thianthrene compound is 2-acetylthianthrene.
  • the difference of this example is that in the negative electrode slurry, the thianthrene compound is 2,7-diacetylthianthrene.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the thianthrene compound is 2,7-dibromothianthrene.
  • the difference of this example is that in the negative electrode slurry, the thianthrene compound is 2,7-diisobutyrylthianthrene.
  • Example 1 Compared with Example 1, the difference of this comparative example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 0 parts.
  • Example 1 Compared with Example 1, the difference of this comparative example is that in the negative electrode slurry, the weight portion of the thianthrene compound is 6 parts.
  • Example 2 Compared with Example 1, the difference of this example is that in the negative electrode slurry, the D50 of the thianthrene compound is 0.2 ⁇ m.
  • Example 1 Compared with Example 1, the difference of this comparative example is that in the negative electrode slurry, the D50 of the thianthrene compound is 10 ⁇ m.
  • Example 6 Compared with Example 6, the difference of this comparative example is that a thianthrene pore former is added to the active slurry of the first active sublayer, and the second active sublayer is a negative electrode slurry without a pore former.
  • the test method for the capacity of a lithium-ion battery is as follows: at 25°C, first charge the battery to 3.65V at a constant current of 1C, then charge it to a current of 0.05C at a constant voltage of 3.65V, and then discharge it to 2.5V at a constant current of 1C. This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the first cycle.
  • the test method for the rate performance of lithium-ion batteries is as follows: at 25°C, the battery is first charged to 3.65V at a constant current of 1C, further charged to a current of 0.05C at a constant voltage of 3.65V, and then discharged to 2.5V at a constant current of 1C.
  • This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the first cycle; then the battery cell is charged to 3.65V at a constant current of 1C, further charged to a current of 0.05C at a constant voltage of 3.65V, and then discharged to 2.5V at a constant current of 2C.
  • This is a charge and discharge cycle process, and the discharge capacity this time is the discharge capacity of the second cycle, and the ratio of the discharge capacity of the second cycle to the discharge capacity of the first cycle is recorded as the 2C rate capacity retention rate.
  • the internal resistance test method of the battery is: use a 1KHz sinusoidal current to test the voltage drop caused and calculate the internal resistance.

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

La présente invention concerne une composition d'électrode négative et son procédé de préparation, une suspension d'électrode négative et son procédé de préparation, une feuille d'électrode négative et son procédé de préparation, une batterie secondaire, un dispositif électrique et l'utilisation d'un composé thianthrène. La composition d'électrode négative contient un matériau actif d'électrode négative et un composé thianthrène.
PCT/CN2022/121750 2022-09-27 2022-09-27 Composition d'électrode négative et son procédé de préparation, suspension d'électrode négative et son procédé de préparation, feuille d'électrode négative et son procédé de préparation, batterie secondaire, dispositif électrique et utilisation d'un composé thianthrène WO2024065181A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150333331A1 (en) * 2014-05-13 2015-11-19 Arizona Board Of Regents On Behalf Of Arizona State University Electrochemical energy storage devices comprising self-compensating polymers
CN109312023A (zh) * 2016-08-05 2019-02-05 赢创德固赛有限公司 含有噻蒽的聚合物作为电荷存储的用途
KR102013530B1 (ko) * 2018-10-23 2019-08-23 재단법인 하이브리드 인터페이스기반 미래소재 연구단 염료―흑연 리튬이온 배터리용 음극재 및 그 제조방법
CN112467193A (zh) * 2021-01-28 2021-03-09 上海瑞浦青创新能源有限公司 一种安全型锂离子电池及其制备方法
CN114883677A (zh) * 2022-05-26 2022-08-09 上海瑞浦青创新能源有限公司 一种锂离子电池的预锂方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150333331A1 (en) * 2014-05-13 2015-11-19 Arizona Board Of Regents On Behalf Of Arizona State University Electrochemical energy storage devices comprising self-compensating polymers
CN109312023A (zh) * 2016-08-05 2019-02-05 赢创德固赛有限公司 含有噻蒽的聚合物作为电荷存储的用途
KR102013530B1 (ko) * 2018-10-23 2019-08-23 재단법인 하이브리드 인터페이스기반 미래소재 연구단 염료―흑연 리튬이온 배터리용 음극재 및 그 제조방법
CN112467193A (zh) * 2021-01-28 2021-03-09 上海瑞浦青创新能源有限公司 一种安全型锂离子电池及其制备方法
CN114883677A (zh) * 2022-05-26 2022-08-09 上海瑞浦青创新能源有限公司 一种锂离子电池的预锂方法

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