WO2024114403A1 - 用于电池的正极极片、电池、装置及制备方法 - Google Patents

用于电池的正极极片、电池、装置及制备方法 Download PDF

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Publication number
WO2024114403A1
WO2024114403A1 PCT/CN2023/132181 CN2023132181W WO2024114403A1 WO 2024114403 A1 WO2024114403 A1 WO 2024114403A1 CN 2023132181 W CN2023132181 W CN 2023132181W WO 2024114403 A1 WO2024114403 A1 WO 2024114403A1
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Prior art keywords
positive electrode
component
battery
electrode material
lithium
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PCT/CN2023/132181
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English (en)
French (fr)
Inventor
任瑞丽
陈文荚
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兰钧新能源科技有限公司
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Publication of WO2024114403A1 publication Critical patent/WO2024114403A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • 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
    • H01M4/139—Processes of manufacture
    • 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
    • H01M2004/028—Positive 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

  • Embodiments of the present disclosure relate to a positive electrode sheet for a battery, a battery, a device, and a preparation method.
  • Lithium-ion batteries have the advantages of high energy density, high operating voltage, light weight, small size, and green environmental protection, and are widely used in various fields.
  • the positive electrode collector plays the role of transmitting electrons, attaching positive electrode active materials, and providing a certain mechanical strength for the positive electrode sheet.
  • Traditional positive electrode collectors are mainly prepared by casting, cold rolling, foil rolling and other processes on aluminum alloy materials.
  • At least one embodiment of the present disclosure relates to a positive electrode sheet for a battery, a battery containing the positive electrode sheet, a device containing the battery, and a method for preparing the positive electrode sheet for a battery, so that the positive electrode sheet has a higher energy density while improving its thermal stability to have higher safety performance.
  • the positive electrode sheet for a battery provided in at least one embodiment of the present disclosure, 0.85 ⁇ 1.2.
  • the positive electrode sheet for a battery provided in at least one embodiment of the present disclosure, 0.9 ⁇ 1.1.
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is less than or equal to 306°C, and the temperature of the second component at the exothermic peak in the differential scanning calorimetry characterization is greater than 306°C.
  • the gram capacity of the first component is greater than or equal to 150 mA ⁇ h/g, and the gram capacity of the second component is less than 150 mA ⁇ h/g.
  • the first component includes at least one of a ternary material, lithium cobalt oxide, and lithium nickel oxide
  • the second component includes at least one of an olivine material, a spinel material, and a ternary layered compound with a low nickel content, and the mass percentage of nickel in the ternary layered compound with a low nickel content is 30%-80%.
  • the olivine material includes at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, and lithium manganate.
  • the positive electrode plate for a battery provided in at least one embodiment of the present disclosure further includes a positive electrode current collector, and the positive electrode material layer is provided on at least one side of the positive electrode current collector.
  • the positive electrode current collector is a composite current collector, and the positive electrode current collector has a first resistor R1, and the first resistor R1 satisfies: 20m ⁇ R1 ⁇ 100m ⁇ .
  • the positive electrode plate for a battery provided by at least one embodiment of the present disclosure also includes a coating, wherein the coating is located between the positive electrode material layer and the positive electrode current collector, and the coating has a second resistance R2, wherein the second resistance R2 satisfies: 20m ⁇ R2 ⁇ 1000m ⁇ , and the thickness H of the coating satisfies: 0.5 ⁇ m ⁇ H ⁇ 5 ⁇ m.
  • the thickness H of the coating satisfies: 1 ⁇ m ⁇ H ⁇ 3 ⁇ m.
  • the second resistance R2 of the coating satisfies: 10 m ⁇ R2 ⁇ 300 m ⁇ .
  • the material of the coating includes an inorganic material, a conductive agent and a binder
  • the inorganic material includes at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium-rich manganese-based material, lithium nickel cobalt aluminum oxide, and lithium titanate
  • the conductive agent includes at least one of carbon black, carbon fiber, carbon nanotubes, graphite, graphene, metal powder, conductive polymer, and conductive ceramic powder
  • the binder includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, and lithium carboxymethyl cellulose.
  • the capacity of the battery is greater than 10A ⁇ h.
  • the capacity of the battery is greater than or equal to 100A ⁇ h.
  • the capacity of the battery is greater than or equal to 100A ⁇ h and less than or equal to 115A ⁇ h.
  • At least one embodiment of the present disclosure further provides a battery, comprising the positive electrode plate as described in any one of the above items.
  • At least one embodiment of the present disclosure further provides a device, which further includes the above-mentioned battery, and the battery is configured to serve as a power source for the device.
  • At least one embodiment of the present disclosure further provides a method for preparing a positive electrode sheet for a battery, comprising: forming a positive electrode material layer containing a positive electrode material, wherein forming the positive electrode material layer containing a positive electrode material comprises:
  • a preparation method is provided, wherein 0.85 ⁇ 1.2.
  • a preparation method is provided, wherein 0.9 ⁇ 1.1.
  • a preparation method is provided, wherein the temperature of the first component at the exothermic peak in differential scanning calorimetry characterization is less than or equal to 306°C, and the temperature of the second component at the exothermic peak in differential scanning calorimetry characterization is greater than 306°C.
  • a preparation method wherein the gram capacity of the first component is greater than or equal to 150 mA ⁇ h/g, and the gram capacity of the second component is less than 150 mA ⁇ h/g.
  • FIG1 is a schematic diagram of the structure of a positive electrode plate provided in an embodiment of the present disclosure.
  • FIG. 2 is a schematic diagram of the structure of another positive electrode plate provided in an embodiment of the present disclosure.
  • ternary materials are commonly used materials with high energy density, and as the nickel content increases, the gram capacity of ternary materials will increase accordingly, which can further increase the energy density of lithium-ion batteries.
  • the thermal stability of the positive electrode material of the lithium-ion battery will decrease, so that heat generation and oxygen release may occur at lower temperatures, making the safety of the battery cells in the lithium-ion battery lower. Therefore, when lithium-ion batteries are subjected to mechanical abuse tests such as needle puncture, thermal runaway is very likely to occur.
  • Composite current collectors use polymer layers as support layers, and metals are compounded on both sides of the polymer layer by bonding, evaporation, etc. to form a conductive layer, forming a "sandwich" structure of metal layer-polymer layer-metal layer.
  • the thickness of the conductive layer is thicker than that of conventional metal current collectors. Thinner, higher resistance, so smaller short-circuit current, less heat generation, lower temperature rise, thus reducing the probability of thermal runaway of the battery.
  • some technologies also adopt the solution of applying a safety coating on the surface of the positive current collector and then applying the positive electrode material.
  • a safety coating on the surface of the positive current collector and then applying the positive electrode material.
  • four internal short circuits may occur: positive current collector-negative current collector, positive current collector-negative electrode, positive electrode-negative electrode, positive electrode-negative electrode, and positive electrode-negative electrode.
  • the positive current collector-negative electrode is the most dangerous internal short circuit, which can easily cause thermal runaway of the battery.
  • the setting of the safety coating can protect the surface of the positive current collector, increase the resistance between the positive current collector and the negative electrode, reduce the current and heat generated when the positive current collector and the negative electrode have an internal short circuit, reduce the temperature rise, and thus avoid thermal runaway of the battery.
  • the above-mentioned methods for improving the safety of ternary lithium-ion batteries are mostly used in batteries with smaller capacity (for example, batteries with a capacity of less than 10A ⁇ h).
  • batteries with smaller capacity for example, batteries with a capacity of less than 10A ⁇ h.
  • the internal resistance of the battery will decrease. Therefore, when an internal short circuit occurs, the short-circuit current is larger, more heat is generated, and the temperature of the short-circuit point will rise rapidly.
  • the thermal runaway temperature of the ternary material will be reached before the supporting layer is completely shrunk, causing thermal runaway of the battery.
  • safety coating technology is applied, the temperature of the short-circuit point will rise above the thermal runaway temperature of the ternary material, causing thermal runaway of the battery.
  • the positive electrode plate for a battery includes: a positive electrode material layer containing a positive electrode material, the positive electrode material includes a first component and a second component, and the thermal stability of the first component is lower than the thermal stability of the second component.
  • the disclosed embodiment can improve the thermal stability of the positive electrode plate while having a higher energy density by mixing a second component with a first component with a lower thermal stability, thereby achieving higher safety performance.
  • the following is a description of the positive electrode sheet for a battery and a positive electrode sheet containing the positive electrode sheet in combination with the accompanying drawings and through some embodiments.
  • a battery, a device containing the battery, and a method for preparing a positive electrode sheet are described.
  • FIG1 is a schematic diagram of the structure of a positive electrode plate provided in an embodiment of the present disclosure.
  • At least one embodiment of the present disclosure provides a positive electrode plate 01, which is provided with a positive electrode material layer 10 including a positive electrode material, wherein the positive electrode material includes a first component and a second component, and the thermal stability of the first component is lower than the thermal stability of the second component.
  • ⁇ represents the characteristic ratio of the positive electrode material
  • w represents the mass ratio of the first component to the positive electrode material layer
  • T1 represents the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization, and the unit of T1 is °C
  • Cap represents the capacity of the battery, and the unit of Cap is A ⁇ h.
  • the positive electrode sheet 01 can be used in a secondary battery.
  • the positive electrode sheet can be used in a lithium-ion battery, but is not limited thereto, and the embodiments of the present disclosure are not limited thereto.
  • the first component and the second component can be positive electrode active materials.
  • At least one embodiment of the present disclosure can simplify the complexity by dividing the positive electrode active material of the positive electrode material layer in the positive electrode sheet into two components, which is conducive to classification and selection among a large number of positive electrode active materials.
  • the capacity of the battery is greater than or equal to 100A ⁇ h and less than or equal to 115A ⁇ h.
  • the positive electrode material can be applied to a lithium-ion battery of a power or energy storage type with a capacity of 50A ⁇ h to 200A ⁇ h.
  • the positive electrode material can be applied to a lithium-ion battery of a power or energy storage type with a capacity of 100A ⁇ h to 160A ⁇ h.
  • the positive electrode material can be applied to a lithium-ion battery of a power or energy storage type with a capacity of 120A ⁇ h to 140A ⁇ h, but is not limited thereto.
  • the positive electrode plate 01 provided by at least one embodiment of the present disclosure can enable the battery to have higher safety performance while meeting greater capacity requirements, thereby having greater application potential.
  • the positive electrode sheet provided in the embodiment of the present disclosure in order to facilitate the acquisition of a large-capacity battery and reduce the probability of thermal runaway when the battery is mechanically abused, divides the positive electrode material into two components, namely the first component and the second component.
  • the positive electrode materials of the two components have advantages in thermal stability and energy density.
  • the formula is constructed by the characteristic ratio ⁇ , the capacity Cap of the battery, the temperature T1 at the exothermic peak of the first component in the differential scanning calorimetry characterization, and the mass ratio w of the first component to the positive electrode material layer.
  • the component and content that satisfy the characteristic ratio ⁇ in the formula are the positive electrode sheets that meet the requirements.
  • the embodiment of the present disclosure provides a suitable positive electrode sheet for obtaining a large-capacity battery and reducing the probability of thermal runaway when the battery is mechanically abused.
  • each parameter is linked, and the positive electrode material that satisfies 0.8 ⁇ 1.5 is the positive electrode sheet that meets the requirements.
  • the composition and content of the positive electrode material are adjusted so that the positive electrode material satisfies: 0.85 ⁇ 1.2.
  • the battery using the positive electrode material can have better safety performance and larger battery capacity.
  • the capacity of the battery when the capacity of the battery is determined, the capacity of the battery, the components of the positive electrode material, and the content of the components are adjusted so that the positive electrode material satisfies: 0.9 ⁇ 1.1, so as to better balance safety performance and obtain a large-capacity battery.
  • the battery using the positive electrode material can have better safety performance and a larger battery capacity.
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is less than or equal to 306° C.
  • the temperature of the second component at the exothermic peak in the differential scanning calorimetry characterization is greater than 306° C.
  • the temperature of the exothermic peak of the composition in the differential scanning calorimetry characterization is determined. That is, the temperature of the exothermic peak in the differential scanning calorimetry characterization is a parameter related to the composition, which is a constant value when the composition is determined.
  • the temperature at the exothermic peak in the differential scanning calorimetry characterization is obtained using a common differential scanning calorimeter, and the corresponding national standard (GB) is JB/T 6856-2017.
  • the differential scanning calorimeter model used in the embodiments of the present disclosure is Mettler Toledo DSC 3+. Of course, other differential scanning calorimeters can also be used for measurement.
  • the thermal stability of the first component is lower than that of the second component, and the thermal effect generated by the first component per unit time is higher than the thermal effect generated by the second component per unit time.
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization may be 100°C-306°C, but is not limited thereto.
  • the exothermic peak temperature limit of the first component and the second component is 306°C, but is not limited thereto.
  • the gram capacity of the first component is greater than or equal to 150 mA ⁇ h/g, and the gram capacity of the second component is less than 150 mA ⁇ h/g.
  • the positive electrode active material is further screened, so that the boundary between the first component and the second component is clearer.
  • the gram capacity of the active component in the positive electrode material is related to the component.
  • the gram capacity of the component is determined.
  • the gram capacity is measured using common test conditions.
  • the measurement standard of the gram capacity refers to GB/T 23365-2009.
  • the energy density of the first component is greater than the energy density of the second component, and the gram capacity of the first component and the second component is limited to 150 mA ⁇ h/g, but is not limited thereto. Therefore, by blending the first component with the second component, the overall energy density of the positive electrode material of the positive electrode sheet 01 can be improved, so that the battery has a higher energy density.
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is less than or equal to 306°C
  • the temperature of the second component at the exothermic peak in the differential scanning calorimetry characterization is greater than 306°C
  • the gram capacity of the first component is greater than or equal to 150mA ⁇ h/g
  • the gram capacity of the second component is less than 150mA ⁇ h/g.
  • the positive electrode active material that meets this condition is more conducive to taking into account both safety performance and obtaining a large-capacity battery.
  • the energy density of a battery refers to the ratio of the energy of the battery to its volume.
  • the first component may include at least one of a ternary material, lithium cobaltate, and lithium nickelate
  • the second component may include at least one of an olivine material, a spinel material, and a ternary layered compound with a low nickel content
  • the percentage of nickel in the ternary layered compound with a low nickel content is 30%-80%, but is not limited thereto.
  • the mass percentage of nickel in the ternary layered compound with a low nickel content may be 30%-50%.
  • the mass percentage of nickel in the ternary layered compound with a low nickel content may be 40%-60%.
  • the mass percentage of nickel in the ternary layered compound with a low nickel content may be 44%-55%.
  • the olivine material may include lithium iron phosphate, At least one of lithium iron manganese, lithium vanadium phosphate, and lithium manganate, but not limited thereto.
  • the battery can have a higher safety performance while meeting a larger capacity requirement.
  • the positive electrode plate 01 further includes a positive electrode collector 20 , at least one side of the positive electrode collector 20 is provided with a positive electrode material layer 10 , and the positive electrode collector 20 has a first resistor R1 .
  • the positive electrode current collector 20 may be a composite current collector and include a support layer 22 and a conductive layer 21 disposed on both sides of the support layer 22.
  • the support layer 22 may include a polymer, but is not limited thereto.
  • the support layer 22 includes an insulating material, for example, the insulating material may include at least one of PET (polyethylene glycol terephthalate), PE (Polyethylene), PVC (Polyvinyl chloride), PP (Polypropylene), BOPP (Biaxially oriented polypropylene film), OPS (Oriented Polystyrene Films) and POF (Polyolefin), but is not limited thereto.
  • the positive electrode material layer 10 may be located only on one side of the positive electrode current collector 20, that is, only one layer of the positive electrode material layer 10 is provided in the positive electrode plate 01.
  • the positive electrode material layer 10 may be located on two opposite sides of the positive electrode current collector 20, that is, two layers of the positive electrode material layer 10 are provided in the positive electrode plate 01, but it is not limited thereto.
  • the thickness of the conductive layer 21 in the positive electrode collector 20 is thinner than that of a conventional metal current collector and the resistance is larger, the short-circuit current is smaller, the heat generation is less, and the temperature rise is lower, thereby reducing the probability of thermal runaway of the battery.
  • the structure of the positive electrode current collector 20 is not limited to that shown in FIG. 1 , and the positive electrode current collector 20 may be made of a metal material, such as aluminum foil, but is not limited thereto.
  • the embodiment of the present disclosure mixes a first component with lower thermal stability with a second component with higher thermal stability in the positive electrode material of the positive electrode plate 01, and sets a positive electrode current collector 20 containing a support layer in the positive electrode plate 01. Since the short-circuit current of the conductive layer 21 in the positive electrode current collector 20 is smaller, the heat generation is less, and the temperature rise is lower, the probability of thermal runaway of the battery can be reduced.
  • the thermal runaway temperature of the positive electrode of the battery can be made to be above the temperature of the internal short-circuit point when mechanical abuse such as needle puncture occurs, thereby reducing the probability of thermal runaway of the battery.
  • the positive electrode material is combined with the positive electrode current collector 20 of the composite current collector structure, which can be beneficial to solve the problem of thermal runaway of the battery.
  • Large-capacity ternary lithium-ion batteries for power and energy storage cannot survive mechanical abuse such as needle puncture.
  • the first resistor R1 of the positive electrode current collector 20 may be the square resistance of the positive electrode current collector 20.
  • the current in the battery may be controlled within a reasonable range to avoid reducing the safety performance of the battery (e.g., battery cell) when the current is too large, and affecting the electrical performance of the battery when the current is too small.
  • the square resistance test method of the first resistor R1 may refer to GBT1552-1995, but is not limited thereto.
  • the first resistor R1 of the positive electrode current collector 20 may be 40 m ⁇ to 60 m ⁇ to better control the current in the battery so that the battery has good electrical performance and high safety.
  • FIG. 2 is a schematic diagram of the structure of another positive electrode plate provided in an embodiment of the present disclosure.
  • the positive electrode sheet 02 includes a positive electrode material 30, a coating 31 and a positive current collector 32.
  • the positive electrode material 30 is disposed on at least one side of the positive current collector 32.
  • FIG2 takes the case where the positive electrode material 30 is disposed on both sides of the positive current collector 32 as an example for explanation.
  • the coating 31 is disposed between the positive electrode material 30 and the positive current collector 32, and the coating 31 has a second resistor R2.
  • the second resistor R2 satisfies: 20m ⁇ R2 ⁇ 1000m ⁇ , and the thickness H of the coating satisfies: 0.5 ⁇ m ⁇ H ⁇ 5 ⁇ m.
  • the coating 31 can be used as a safety coating of the positive electrode sheet 02 to protect the surface of the positive current collector 32.
  • the provision of the coating 31 can increase the resistance between the positive current collector 32 and the negative electrode in the battery, thereby reducing the current and heat generation when the positive current collector 32 and the negative electrode are short-circuited internally, so as to reduce the temperature rise. Therefore, when the battery is subjected to mechanical abuse such as puncture, the coating 31 can control the temperature of the short-circuit point of the battery to below the thermal runaway temperature of the positive electrode material 30 when the negative electrode of the battery comes into contact with the positive electrode collector 32, thereby avoiding thermal runaway of the battery.
  • the thickness of the coating 31 may satisfy: 1 ⁇ m ⁇ H ⁇ 3 ⁇ m, so as to control the resistance between the positive electrode collector 32 and the negative electrode in the battery, and control the temperature of the short-circuit point of the battery below the thermal runaway temperature of the positive electrode material 30 , thereby avoiding thermal runaway of the battery.
  • the second resistance of the coating 31 may satisfy: 10 m ⁇ R2 ⁇ 300 m ⁇ , so as to control the temperature of the short-circuit point of the battery below the thermal runaway temperature of the positive electrode material 30 and reduce the probability of thermal runaway of the battery.
  • the positive electrode current collector 32 may be different from the composite current collector in the above embodiment.
  • the positive electrode current collector 32 may be made of a metal material, such as aluminum foil, but is not limited thereto.
  • the material of the coating layer includes an inorganic material, a conductive agent, and a binder, but is not limited thereto.
  • the inorganic material may include at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadium phosphate, lithium-rich manganese-based materials, lithium nickel cobalt aluminum oxide, and lithium titanate, but is not limited thereto.
  • the conductive agent may include at least one of carbon black, carbon fiber, carbon nanotube, graphite, graphene, metal powder, conductive polymer, and conductive ceramic powder, but is not limited thereto.
  • the binder may include at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, and lithium carboxymethyl cellulose, but is not limited thereto.
  • the selection of inorganic materials can be determined according to actual design requirements to effectively control the short-circuit point temperature of different batteries and improve thermal stability, which is not limited in the embodiments of the present disclosure.
  • the battery provided in the embodiments of the present disclosure may be a lithium-ion battery, but is not limited thereto.
  • the positive electrode sheet may be the positive electrode sheet 01 or the positive electrode sheet 02 in the above embodiments.
  • the various composition parameters of the positive electrode sheet in the battery please refer to the above related description, which will not be repeated here.
  • the positive electrode plate by mixing a second component with higher thermal stability into a first component with lower thermal stability, the positive electrode plate can have a higher energy density while improving thermal stability to reduce the probability of thermal runaway and have higher safety performance.
  • An embodiment of the present disclosure further provides a device, which includes the battery provided in any of the above embodiments, and the battery is configured as a power source for the device.
  • the device provided by the embodiments of the present disclosure may be a car, such as an electric car.
  • the electric car may be any one of an electric pure electric car, a hybrid electric car, and a plug-in hybrid electric car, but is not limited thereto.
  • the electric car may be any one of an electric bus, an electric tram, an electric bicycle, an electric motorcycle, an electric scooter, an electric golf cart, and an electric truck, but is not limited thereto.
  • the device provided by the embodiments of the present disclosure may also be any one of an electric ship, an electric tool, an electronic device, and an energy storage system, but is not limited thereto.
  • the positive electrode plate can have a higher energy density while improving thermal stability, so as to reduce the probability of thermal runaway, have higher safety performance, and facilitate obtaining a large-capacity battery.
  • At least one embodiment of the present disclosure also provides a method for preparing a positive electrode sheet for a battery.
  • the preparation method comprises: forming a positive electrode material layer containing a positive electrode material.
  • w is the mass ratio of the first component to the positive electrode material layer
  • T1 is the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization
  • T1 is in °C
  • Cap is the capacity of the battery
  • Cap is in A ⁇ h
  • ⁇ is the characteristic ratio of the positive electrode material.
  • the positive electrode sheet produced by the above method is conducive to obtaining a large-capacity battery and reducing the probability of thermal runaway when the battery is mechanically abused.
  • the positive electrode material can also be applied to scenarios with larger capacity requirements, such as power or energy storage lithium-ion batteries with a capacity greater than 10A ⁇ h to meet larger battery capacity requirements.
  • the capacity of the battery is greater than or equal to 100A ⁇ h.
  • the capacity of the battery is greater than or equal to 100A ⁇ h, and less than or equal to 115A ⁇ h, but is not limited to this.
  • the positive electrode sheet prepared by this preparation method can enable the battery to have higher safety performance while meeting larger capacity requirements, thus having greater application potential.
  • the components and content in the positive electrode material when preparing the positive electrode material layer of the positive electrode sheet, under the condition of a given battery capacity, the battery capacity, the components and content in the positive electrode material can be adjusted so that the positive electrode material satisfies: 0.85 ⁇ 1.2.
  • the battery using the positive electrode material can have better safety performance and larger battery capacity.
  • the capacity of the battery and the content of the first component and the second component in the positive electrode material can be adjusted so that the positive electrode material satisfies: 0.9 ⁇ 1.1.
  • the battery using the positive electrode material can have better safety performance and larger battery capacity.
  • the temperature of the first component in the positive electrode material at the exothermic peak in the differential scanning calorimetry characterization can be less than or equal to 306°C, and the temperature of the second component at the exothermic peak in the differential scanning calorimetry characterization is greater than 306°C, but is not limited thereto.
  • the exothermic peak temperature of 306°C in the differential scanning calorimetry characterization as a boundary, the two components in the positive electrode material are distinguished, which is beneficial to the selection of the positive electrode material components and the acquisition of the content.
  • the thermal stability of the first component lower than the thermal stability of the second component, the thermal effect generated by the first component per unit time is higher than the thermal effect generated by the second component per unit time.
  • the exothermic peak temperature limit of the first component and the second component can be 306°C.
  • the thermal stability of the positive electrode material of the positive electrode sheet 01 can be improved, so that the battery has higher safety.
  • the gram capacity of the first component in the positive electrode material can be greater than or equal to 150mA ⁇ h/g, and the gram capacity of the second component can be less than 150mA ⁇ h/g, but not limited to this.
  • the positive electrode active material is further screened, so that the boundary between the first component and the second component is clearer.
  • the energy density of the first component can be greater than the energy density of the second component, and the gram capacity of the first component and the second component is limited to 150 mA ⁇ h/g.
  • the overall energy density of the positive electrode material of the positive electrode sheet 01 can be improved, so that the battery has a higher energy density.
  • the method for preparing the positive electrode plate may further include the following steps.
  • Step (1) coating a coating material on at least one side of the positive electrode current collector.
  • Step (2) disposing the positive electrode material layer on the side of the coating material away from the positive electrode current collector, and performing a drying process.
  • Step (3) cold pressing the dried positive electrode sheet.
  • Step (4) cutting the cold pressed positive electrode sheet into a specified size.
  • the temperature of the short-circuit point of the battery is controlled below the thermal runaway temperature of the positive electrode material, thereby avoiding thermal runaway of the battery.
  • the battery provided in at least one embodiment of the present disclosure may further include a negative electrode sheet and an electrolyte.
  • the preparation process of the battery may include the following steps.
  • the preparation method of the positive electrode sheet in the battery can refer to the relevant description in the above embodiment, which will not be repeated here.
  • the positive electrode sheet is made in sequence to form a positive electrode sheet.
  • the step of making the coating is omitted.
  • a positive electrode collector of a corresponding structure is used to replace the positive electrode collector of the composite structure.
  • the negative electrode plate in the battery may include a negative electrode current collector, a negative electrode material layer and a negative electrode coating.
  • the negative electrode coating may be disposed on at least one side of the negative electrode current collector, and the negative electrode material layer may be disposed on the side of the negative electrode coating away from the negative electrode current collector.
  • the negative electrode material layer may include a negative electrode material.
  • the negative electrode material may include a negative electrode active substance, and the components of the negative electrode active substance are not specifically limited.
  • the negative electrode active substance may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, mesophase carbon microspheres, silicon-based materials, tin-based materials, and lithium titanate.
  • the negative electrode coating may include a conductive agent and a binder, but is not limited thereto.
  • the negative electrode current collector may include copper foil, but is not limited thereto, and may be selected according to actual needs.
  • the electrolyte in the battery may include a lithium salt and an organic solvent, but is not limited thereto.
  • the lithium salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium perchlorate.
  • the organic solvent may include at least one of a cyclic carbonate, a chain carbonate, and a carboxylate.
  • the electrolyte may also contain functional additives, such as vinylene carbonate, vinyl sulfate, propane sultone, fluoroethylene carbonate, etc. At least one embodiment of the present disclosure does not limit the material of the electrolyte.
  • the separator layer of the battery may include a polyethylene film, but is not limited thereto.
  • the positive electrode sheet, the isolation film layer, and the negative electrode sheet can be stacked in sequence, and the isolation film layer can be located between the positive electrode sheet and the negative electrode sheet. Then, the stacked structure can be wound to obtain a bare cell. Next, the bare cell is placed in the outer packaging of the battery. The battery is then placed in a shell and dried, and then the electrolyte is injected. Finally, after vacuum packaging, standing, forming, shaping and other processes, a battery is obtained.
  • the battery provided by at least one embodiment of the present disclosure is described below in the form of an embodiment.
  • the first component of the positive electrode material in the positive electrode plate 01 of the battery is a ternary material
  • the second component is lithium iron phosphate.
  • the first component can be a ternary material with different nickel contents, for example, the nickel content of the first component (ternary material) with a thermal runaway temperature of 264°C is 60%; for example, the nickel content of the first component (ternary material) with a thermal runaway temperature of 298°C is 33%; the nickel content of the first component (ternary material) with a thermal runaway temperature of 225°C is 80%.
  • the first resistance R1 of the positive electrode current collector of the battery used is 50m ⁇ .
  • the negative electrode material in the negative electrode plate of the battery includes a graphite material (eg, artificial graphite or natural graphite).
  • the capacity of the battery may include 100A ⁇ h and 115A ⁇ h, respectively. Then, a needle penetration test is performed on the battery including the positive electrode plate 01 of the above configuration.
  • the needle penetration test method may include: after the battery is fully charged in a CC-CV manner, a ⁇ 5mm high temperature resistant steel needle is used to penetrate the battery plate (such as the positive electrode plate 01) at a speed of 25 ⁇ 5mm/s from a direction perpendicular to the battery plate, so that the steel needle stays in the battery for 1 hour.
  • the resistance of the positive electrode collector is 50m ⁇
  • the battery capacity is 100A ⁇ h or 115A ⁇ h.
  • the needle penetration test method can refer to GB/T 31486-2015, but is not limited thereto.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.70
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode plate of the battery is 1.003
  • the energy density of the battery is 218Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.78
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode plate of the battery is 0.900
  • the energy density of the battery is 223 Wh/kg.
  • the needle penetration test result for this battery is: 9/10p, which means that 9 out of 10 needle penetration tests passed.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.64
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.097
  • the energy density of the battery is 213Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.82
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.856
  • the energy density of the battery is 226Wh/kg.
  • the needle puncture result for the battery is: 8/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.59
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.190
  • the energy density of the battery is 210Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.87
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.807
  • the energy density of the battery is 229Wh/kg.
  • the needle puncture result for the battery is: 7/10p, that is, in 10 needle puncture tests, 7 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.47
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.494
  • the energy density of the battery is 201Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 33%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.78
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 298°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.016
  • the energy density of the battery is 223Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 80%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.58
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 225°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.032
  • the energy density of the battery is 209Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 33%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.73
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 298°C
  • the capacity of the battery is 115A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.075
  • the energy density of the battery is 223Wh/kg.
  • the needle puncture result for the battery is: 10/10p, that is, in 10 needle puncture tests, 10 test results are qualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is a ternary material with a nickel content of 60%.
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component in the positive electrode material layer is 0.95
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the battery capacity is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode plate of the battery is 0.739
  • the energy density of the battery is 235Wh/kg.
  • the needle puncture result for the battery is: 0/10p, that is, in 10 needle puncture tests, 10 test results were unqualified.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.35
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode plate of the battery is 2.006
  • the energy density of the battery is 193Wh/kg.
  • the puncture result for the battery is: 10/10p, that is, in 10 puncture tests, 10 test results are qualified. Table 1 shows Examples 1 to 12 and the corresponding parameters and test results.
  • the probability of the positive electrode material passing the needle puncture test is at least 70%.
  • the probability of the positive electrode material passing the needle puncture test is at least 80%.
  • the probability of the positive electrode material passing the needle puncture test is at least 90%.
  • the numerical range satisfied by ⁇ in the positive electrode material may have a certain fluctuation range, for example, the fluctuation range may be 0.5% to 0.1%, but is not limited thereto.
  • the positive electrode plate 02 is used for testing.
  • the first component uses a ternary material with different nickel contents
  • the second component uses lithium iron phosphate.
  • the positive current collector in the positive electrode plate 02 uses aluminum foil
  • the material of the coating 31 in the positive electrode plate 02 is lithium iron phosphate
  • the second resistance of the coating 31 is 20m ⁇ .
  • the capacity of the battery can include 100A ⁇ h and 115A ⁇ h, respectively. Then, a needle puncture test is performed on the battery configured as above including the positive electrode plate 02.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.70
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.003
  • the energy density of the battery is 221Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.78
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.900
  • the energy density of the battery is 226Wh/kg.
  • the acupuncture result for the battery is: 8/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is a ternary material with a nickel content of 60%.
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component in the positive electrode material layer is 0.64
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.097
  • the energy density of the battery is 216Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.82
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.856
  • the energy density of the battery is 229Wh/kg.
  • the acupuncture result for the battery is: 7/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.59
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.190
  • the energy density of the battery is 213Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.87
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.807
  • the energy density of the battery is 232Wh/kg.
  • the acupuncture result for the battery is: 6/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.47
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.494
  • the energy density of the battery is 204Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 33%
  • the second component is a ternary material with a nickel content of 33%.
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component in the positive electrode material layer is 0.78
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 298°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.016
  • the energy density of the battery is 226Wh/kg.
  • the needle puncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 80%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.58
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 225°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.032
  • the energy density of the battery is 212Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 33%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.73
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 298°C
  • the capacity of the battery is 115A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 1.075
  • the energy density of the battery is 226Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.95
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 0.739
  • the energy density of the battery is 238Wh/kg.
  • the acupuncture result for the battery is: 0/10p.
  • the first component is a ternary material with a nickel content of 60%
  • the second component is lithium iron phosphate
  • the mass ratio w of the first component to the positive electrode material layer is 0.35
  • the temperature of the first component at the exothermic peak in the differential scanning calorimetry characterization is 264°C
  • the capacity of the battery is 100A ⁇ h
  • the characteristic ratio ⁇ of the positive electrode material of the positive electrode sheet of the battery is 2.006
  • the energy density of the battery is 196Wh/kg.
  • the acupuncture result for the battery is: 10/10p.
  • Table 2 shows the results of a needle penetration test on a battery including the positive electrode sheet 02.
  • Example 23 when 0.8 ⁇ 1.5, the battery has a greater probability of passing the puncture test. When 1 ⁇ 1.5, the battery has a higher probability of passing the puncture test.
  • ⁇ is less than 0.8, and the battery can hardly pass the puncture test.
  • ⁇ is greater than 0.8, and although the battery can pass the puncture test, it will result in a decrease in the energy density of the battery.
  • the coating 31 is provided in the positive electrode sheet 02, which can increase the resistance between the positive electrode collector and the negative electrode in the battery, thereby reducing the current and heat generated when the positive electrode collector and the negative electrode are short-circuited, so as to reduce the temperature rise.
  • the positive electrode sheet 02 also uses a positive electrode material that meets the requirements, that is, when the characteristic ratio of the positive electrode material is 0.8 ⁇ 1.5, the energy density of the battery can be maintained at a high level.
  • the positive electrode plate provided in the embodiments of the present disclosure can enable the battery to have higher safety performance while meeting larger capacity requirements, thereby having greater application potential.

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Abstract

提供一种用于电池的正极极片、电池、装置及制备方法。用于电池的正极极片包括：含有正极材料的正极材料层，正极材料包括第一组分和第二组分，第一组分的热稳定性低于第二组分的热稳定性，正极材料满足：τ＝T1*(8-lgCap)/(2256*w)，w为第一组分占正极材料层的质量比例，T1为第一组分在差示扫描量热法表征中的放热峰值处的温度，Cap为电池的容量，Cap单位为A·h，τ为正极材料的特性比值，0.8≤τ≤1.5。本公开实施例通过在热稳定性较低的第一组分中掺混热稳定性较高的第二组分，可使得正极极片在具有较高的能量密度的同时，提高热稳定性，以具有较高的安全性能。

Description

用于电池的正极极片、电池、装置及制备方法
本申请要求于2022年11月28日递交的中国专利申请202211504705.8号的优先权，在此全文引用上述中国专利申请公开的内容以作为本申请的一部分。
技术领域
本公开的实施例涉及一种用于电池的正极极片、电池、装置及制备方法。
背景技术
锂离子电池具有能量密度高、工作电压高、重量轻，体积小、绿色环保等优点，被广泛应用于各个领域。正极集流体作为锂离子电池的重要组成部分，起到传输电子、附着正极活性物质以及为正极极片提供一定机械强度的作用。传统的正极集流体主要通过将铝合金材料经过铸轧、冷轧、箔轧等工艺制备。
发明内容
本公开的至少一实施例涉及一种用于电池的正极极片、含有该正极极片的电池、含有该电池的装置及用于电池的正极极片的制备方法，使得正极极片在具有较高的能量密度的同时，其热稳定性得以提高，以具有较高的安全性能。
本公开的至少一实施例提供一种用于电池的正极极片，包括：含有正极材料的正极材料层，所述正极材料包括第一组分和第二组分，所述第一组分的热稳定性低于所述第二组分的热稳定性，所述第一组分的能量密度大于所述第二组分的能量密度，所述正极材料满足：τ＝T1*(8-lgCap)/(2256*w)，w为所述第一组分占所述正极材料层的质量比例，T1为所述第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为所述电池的容量，Cap单位为A·h，τ为所述正极材料的特性比值，其中，0.8≤τ≤1.5。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，0.85≤τ≤1.2。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，0.9≤τ≤1.1。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，所述第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述第一组分的克容量大于或等于150mA·h/g，所述第二组分的克容量小于150mA·h/g。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述第一组分包括三元材料、钴酸锂、镍酸锂中的至少一种，所述第二组分包括橄榄石材料、尖晶石材料和低镍含量的三元层状化合物中的至少一种，所述低镍含量的三元层状化合物中的镍的质量百分比为30％-80％。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述橄榄石材料包括磷酸铁锂、磷酸锰铁锂、磷酸钒锂、锰酸锂中的至少之一。
例如，本公开的至少一实施例提供的用于电池的正极极片还包括正极集流体，所述正极集流体的至少一侧设有所述正极材料层。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，其中，所述正极集流体为复合集流体，所述正极集流体具有第一电阻R1，所述第一电阻R1满足：20mΩ≤R1≤100mΩ。
例如，本公开的至少一实施例提供的用于电池的正极极片还包括涂层，所述涂层位于所述正极材料层和所述正极集流体之间，所述涂层具有第二电阻R2，其中，所述第二电阻R2满足：20mΩ≤R2≤1000mΩ，且所述涂层的厚度H满足：0.5μm≤H≤5μm。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述涂层的厚度H满足：1μm≤H≤3μm。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述涂层的第二电阻R2满足：10mΩ≤R2≤300mΩ。
例如，在本公开的至少一实施例提供的用于电池的正极极片中，所述涂层的材料包括无机材料、导电剂以及粘结剂，所述无机材料包括磷酸铁锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、富锂锰基材料、镍钴铝酸锂、钛酸锂中的至少一种；所述导电剂包括炭黑、碳纤维、碳纳米管、石墨、石墨烯、金属粉末、导电聚合物、导电陶瓷粉末中的至少一种；所述粘结剂包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、羧甲基纤维素锂中的至少一种。
例如，在本公开至少一个实施例所提供的用于电池的正极极片中，所述电池的容量大于10A·h。
例如，在本公开至少一个实施例所提供的用于电池的正极极片中，所述电池的容量大于或等于100A·h。
例如，在本公开至少一个实施例所提供的用于电池的正极极片中，所述电池的容量大于或等于100A·h，并且小于或等于115A·h。
本公开至少一个实施例还提供一种电池，该电池包括上述任一项所述的正极极片。
本公开至少一个实施例还提供一种装置，该装置还包括上述电池，所述电池被配置为作为所述装置的电源。
本公开至少一个实施例还提供一种用于电池的正极极片的制备方法，包括：形成含有正极材料的正极材料层，形成含有正极材料的正极材料层包括：
在第一组分中掺混第二组分，以制备正极材料，其中，所述第一组分的热稳定性低于所述第二组分的热稳定性，所述正极材料满足：τ＝T1*(8-lgCap)/(2256*w)，w为所述第一组分占所述正极材料层的质量比例，T1为所述第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为所述电池的容量，Cap单位为A·h，τ为所述正极材料的特性比值，其中，0.8≤τ≤1.5。
例如，根据本公开至少一个实施例提供的制备方法，其中，0.85≤τ≤1.2。
例如，根据本公开至少一个实施例提供的制备方法，其中，0.9≤τ≤1.1。
例如，根据本公开至少一个实施例提供的制备方法，其中，所述第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，所述第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃。
例如，根据本公开至少一个实施例提供的制备方法，其中，所述第一组分的克容量大于或等于150mA·h/g，所述第二组分的克容量小于150mA·h/g。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对实施例的附图作简单地介绍，显而易见地，下面描述中的附图仅仅涉及本公开的一些实施例，而非对本公开的限制。
图1为本公开的实施例提供的一种正极极片的结构示意图。
图2为本公开的实施例提供的另一种正极极片的结构示意图。
具体实施方式
为使本公开实施例的目的、技术方案和优点更加清楚，下面将结合本公开实施例的附图，对本公开实施例的技术方案进行清楚、完整地描述。显然，所描述的实施例是本公开的一部分实施例，而不是全部的实施例。基于所描述的本公开的实施例，本领域普通技术人员在无需创造性劳动的前提下所获得的所有其他实施例，都属于本公开保护的范围。
除非另外定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的组成部分。同样，“包括”或者“包含”等类似的词语意指出现该词前面的元件或者物件涵盖出现在该词后面列举的元件或者物件及其等同，而不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电性的连接，不管是直接的还是间接的。“上”、“下”、“左”、“右”等仅用于表示相对位置关系，当被描述对象的绝对位置改变后，则该相对位置关系也可能相应地改变。
目前，机械滥用会导致锂离子电池短路，且该短路可能导致锂离子电池热失控，进而导致锂离子电池出现安全性问题。为了提高锂离子电池的抵抗机械滥用的性能，可以采用多种技术手段，然而，这些技术手段虽然提高了锂离子电池的安全性能，但是可能对锂离子电池的体积能量密度影响较大。因此，在提升锂离子电池安全性的同时，加大电池的能量密度成为目前亟待解决的问题。
例如，在锂离子电池中，三元材料作为一种常用材料，其具有较高的能量密度，并且随着镍含量的提高，三元材料的克容量会随之提高，可进一步增加锂离子电池的能量密度。然而，随着镍含量的提高，锂离子电池的正极材料的热稳定会降低，从而在较低的温度下可能出现产热、释氧等情况，使锂离子电池中电芯的安全性变低。因此，在锂离子电池进行针刺等机械滥用测试时，极易发生热失控。
例如，为提升三元类锂离子电池的安全性，部分技术使用了复合集流体。复合集流体使用聚合物层作为支撑层，通过粘结、蒸镀等方式将金属复合在聚合物层两侧以形成导电层，形成一种金属层-聚合物层-金属层的“三明治”结构。当三元类锂离子电池发生机械滥用时，由于导电层的厚度较常规金属集流体更 薄，电阻更大，因此短路电流更小，产热更少，温升更低，从而降低了电池发生热失控的概率。
例如，为提升三元类锂离子电池的安全性，部分技术还采用了在正极集流体表面涂布安全涂层后，再涂布正极材料的方案。例如，在电池发生机械滥用时，会发生正极集流体-负极集流体、正极集流体-负极、正极-负极集流体、正极-负极四种内短路情况，并且正极集流体-负极是最危险的内短路方式，极易引起电池的热失控。安全涂层的设置可保护正极集流体表面，增加正极集流体与负极之间的阻值，减小正极集流体与负极发生内短路时的电流与产热，降低温升，进而避免电池发生热失控。
但是，上述提升三元类锂离子电池的安全性的方式多应用在容量较小的电池中(例如，容量小于10A·h的电池)。当电池容量增大时，电池的内阻会降低，因此在发生内短路时，短路电流更大，产热更多，短路点的温度会迅速上升。在这种情况下，即使应用复合集流体，也会在支撑层完全收缩前，达到三元材料的热失控温度，进而造成电池发生热失控。或者，即使应用安全涂层技术，短路点的温度也会升高到三元材料的热失控温度以上，进而造成电池发生热失控。
由于目前应用于动力类或储能类的锂离子电池的容量均在10A·h以上(例如，多数在100A·h左右)，因此上述技术无法解决动力类与储能类电池在发生机械滥用时的安全性问题。
本公开至少一个实施例提供一种用于电池的正极极片、电池、装置及制备方法。该用于电池的正极极片包括：含有正极材料的正极材料层，正极材料包括第一组分和第二组分，且第一组分的热稳定性低于第二组分的热稳定性。正极材料满足：τ＝T1*(8-lgCap)/(2256*w)，w为第一组分占正极材料层的质量比例，T1为第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为电池的容量，Cap单位为A·h，τ为正极材料的特性比值，其中，0.8≤τ≤1.5。
本公开实施例通过在热稳定性较低的第一组分中掺混热稳定性较高的第二组分，可使得正极极片在具有较高的能量密度的同时，提高热稳定性，以具有较高的安全性能。
下面结合附图并通过一些实施例对用于电池的正极极片、含有该正极极片 的电池、含有该电池的装置及正极极片的制备方法进行说明。
图1为本公开的实施例提供的一种正极极片的结构示意图。
参考图1，本公开至少一个实施例提供一种正极极片01，该正极极片设置有包括正极材料的正极材料层10，正极材料包括第一组分和第二组分，且第一组分的热稳定性低于第二组分的热稳定性。该正极材料满足下述公式：
τ＝T1*(8-lgCap)/(2256*w)
τ表示正极材料的特性比值；w表示第一组分占正极材料层的质量比例；T1表示第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃；Cap表示电池的容量，Cap单位为A·h。
在该正极材料中，0.8≤τ≤1.5。
例如，正极极片01可用于二次电池。例如，正极极片可用于锂离子电池，但不限于此，本公开的实施例对此不作限定。例如，第一组分和第二组分可以为正极活性材料。
本公开的至少一个实施例通过将正极极片中的正极材料层的正极活性材料划分为两个组分，可化纷繁为简明，利于在众多的正极活性材料中进行归类和选择。
在正极材料层10中，通过合理选取第一组分和第二组分，使得在热稳定性较低的第一组分中掺混热稳定性较高的第二组分，可以降低电池出现产热、释氧等情况，以及在电池发生机械滥用时出现热失控的概率。同时，该正极材料可以应用于较大电容量需求的场景。例如，该正极材料可以应用于容量大于10A·h的动力类或储能类的锂离子电池，以满足较大的电池容量需求。进一步地，例如，该正极材料可以应用于容量大于或等于100A·h的动力类或储能类的锂离子电池。
例如，在本公开的实施例中，电池的容量大于或等于100A·h，并且小于或等于115A·h。例如，该正极材料可以应用于容量为50A·h～200A·h的动力类或储能类的锂离子电池。例如，该正极材料可以应用于容量为100A·h～160A·h的动力类或储能类的锂离子电池。该正极材料可以应用于容量为120A·h～140A·h的动力类或储能类的锂离子电池，但不限于此。
因此，本公开的至少一个实施例提供的正极极片01可以使电池在拥有较高的安全性能的同时，能够满足较大的容量需求，以具有较大的应用潜力。
本公开的实施例提供的正极极片，为了利于获得大容量的电池，并降低在电池发生机械滥用时出现热失控的概率，将正极材料划分为两个组分，即第一组分和第二组分，该两个组分的正极材料在热稳定性和能量密度这两个方面各有优势，且通过特性比值τ、电池的容量Cap、第一组分在差示扫描量热法表征中的放热峰值处的温度T1以及第一组分占正极材料层的质量比w例构建公式，满足该公式中的特性比值τ的组分和含量，即为满足要求的正极极片。本公开的实施例为获得大容量的电池，并降低在电池发生机械滥用时出现热失控的概率的电池，提供合适的正极极片。在该公式中，各参数联动，满足0.8≤τ≤1.5的正极材料，即为满足要求的正极极片。
例如，在本公开的一些实施例中，在电池的容量确定的情况下，通过调整电池的容量、正极材料的组分和含量，使得正极材料满足：0.85≤τ≤1.2。从而，可以使得采用该正极材料的电池具有较好的安全性能，以及较大的电池容量。
例如，在本公开的一些实施例中，在电池的容量确定的情况下，通过调整电池的容量、正极材料的组分和组分的含量，使得正极材料满足：0.9≤τ≤1.1，以利于更好的兼顾安全性能和获得大容量的电池。从而，可以使得采用该正极材料的电池具有更好的安全性能，以及更大的电池容量。
例如，参考图1，对于用于电池的正极极片01中的正极材料，第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃。通过以差示扫描量热法表征中的放热峰值处的温度为306℃作为分界，来区分正极材料中的两个组分，利于正极材料组分的选择和含量的获得。
例如，在正极活性材料的组分确定的情况下，该组分在差示扫描量热法表征中的放热峰值处的温度是确定的。即，差示扫描量热法表征中的放热峰值处的温度是与组分相关的参数，其在组分确定的情况下为定值。
例如，在本公开的实施例中，在差示扫描量热法表征中的放热峰值处的温度采用通常的差示扫描量热仪来获得，对应的国标(GB)为JB/T 6856-2017。本公开的实施例采用的差示扫描量热仪型号为梅特勒托利多DSC 3+。当然，也可以采用其他的差示扫描量热仪来测量。
例如，第一组分的热稳定性低于第二组分的热稳定性，第一组分在单位时间内产生的热效应高于第二组分在单位时间内产生的热效应。
例如，第一组分在差示扫描量热法表征中的放热峰值处的温度可以为100℃-306℃，但不限于此。例如，第一组分和第二组分的放热峰值温度界限为306℃，但不限于此。由此，通过将第二组分与第一组分进行掺混，可以使得正极极片01的正极材料的热稳定性得到改善，以使得电池具有较高的安全性。
例如，参考图1，对于用于电池的正极极片01中的正极材料，第一组分的克容量大于或等于150mA·h/g，第二组分的克容量小于150mA·h/g。通过对正极活性材料组分的克容量进行进一步限定，进一步筛选正极活性材料，使得第一组分和第二组分的界限更加明晰。
正极材料中的活性组分的克容量与该组分有关，在组分确定的情况下，该组分的克容量是确定的。克容量采用通常的测试条件来测量。本公开的实施例中，克容量的测量标准参照GB/T 23365-2009。
例如，在正极极片01的正极材料中，第一组分的能量密度大于第二组分的能量密度，且第一组分与第二组分的克容量以150mA·h/g为界限，但不限于此。由此，通过将第一组分与第二组分掺混，可以使得正极极片01的正极材料的整体能量密度得到改善，以使得电池具有较高的能量密度。
例如，在一些实施例中，第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃，并且第一组分的克容量大于或等于150mA·h/g，第二组分的克容量小于150mA·h/g。通过在差示扫描量热法表征中的放热峰值处的温度为306℃为分界，且组分的克容量为150mA·h/g为分界，进一步筛选正极活性材料，满足该条件的正极活性材料更利于兼顾安全性能和获得大容量的电池。
在本公开的实施例中，电池的能量密度是指电池的能量与其体积之比。
例如，参考图1，在正极极片01中，第一组分可以包括三元材料、钴酸锂、镍酸锂中的至少一种，第二组分可以包括橄榄石材料、尖晶石材料和低镍含量的三元层状化合物中的至少一种，低镍含量的三元层状化合物中的镍的百分比为30％-80％，但不限于此。例如，低镍含量的三元层状化合物中的镍的质量百分比可以为30％-50％。例如，低镍含量的三元层状化合物中的镍的质量百分比可以为40％-60％。例如，低镍含量的三元层状化合物中的镍的质量百分比可以为44％-55％。
例如，参考图1，在正极极片01中，橄榄石材料可以包括磷酸铁锂、磷酸 锰铁锂、磷酸钒锂、锰酸锂中的至少之一，但不限于此。
在正极极片01中，通过将第一组分和第二组分以特定比例、合理地选定为上述材料，可以使得电池拥有较高的安全性能的同时，可以满足较大的容量需求。
例如，参考图1，正极极片01还包括正极集流体20，正极集流体20的至少一侧设有正极材料层10，且正极集流体20具有第一电阻R1。
例如，参考图1，正极集流体20可以为一种复合集流体，且包括支撑层22，以及设置在支撑层22的两侧的导电层21。例如，支撑层22可以包括聚合物，但不限于此。例如，支撑层22包括绝缘材料，例如，该绝缘材料可以包括PET(polyethylene glycol terephthalate，聚对苯二甲酸乙二酯)、PE(Polyethylene，聚乙烯)、PVC(Polyvinyl chloride，聚氯乙烯)、PP(Polypropylene，聚丙烯)、BOPP(Biaxially oriented polypropylene film，双向拉伸聚丙烯薄膜)、OPS(Oriented Polystyrene Films，定向聚苯乙烯)以及POF(Polyolefin，多层共挤聚烯烃)中的至少一种，但不限于此。
例如，正极材料层10可以仅位于正极集流体20的一侧，即在正极极片01中仅设置一层正极材料层10。例如，在正极材料层10可以分别位于正极集流体20的相对的两侧，即在正极极片01中设置两层正极材料层10，但不限于此。
通过在正极极片01中设置含有支撑层22正极集流体20，由于正极集流体20中的导电层21的厚度较常规金属集流体更薄，电阻更大，因此短路电流更小，产热更少，温升更低，从而可以降低电池发生热失控的概率。
例如，参考图1，正极集流体20的结构不限于图1所示，正极集流体20可采用金属材料，例如铝箔，但不限于此。
由此，参考图1，本公开的实施例通过在正极极片01的正极材料中，将热稳定性较低的第一组分与热稳定性较高的第二组分进行掺混，并在正极极片01中设置含有支撑层的正极集流体20，由于正极集流体20中的导电层21的短路电流更小，产热更少，温升更低，从而可以降低电池发生热失控的概率。当电池采用该正极极片01时，可以使得该电池的正极热失控温度位于发生针刺等机械滥用时的内短路点的温度以上，降低了电池发生热失控的概率，同时，该正极材料与复合集流体结构的正极集流体20相结合，可以有利于解决用于 动力、储能类的大容量三元锂离子电池无法通过针刺等机械滥用的问题。
例如，参考图1，正极集流体20的第一电阻R1可以为正极集流体20的方阻，通过将第一电阻R1设置为20mΩ～100mΩ，可以将电池内的电流控制在合理范围，以免使得电流过大时电池(例如，电芯)的安全性能降低，以及电流过小时影响电池的电性能。例如，第一电阻R1的方阻测试方法可以参照GBT1552-1995，但不限于此。
例如，参考图1，正极集流体20的第一电阻R1可以为40mΩ～60mΩ，以更好地控制电池内的电流大小，使得电池在具有良好的电性能的同时，还具较高的安全性。
图2为本公开的实施例提供的另一种正极极片的结构示意图。
例如，参考图2，正极极片02包括正极材料30、涂层31和正极集流体32。正极材料30设置在正极集流体32的至少一侧，图2中以正极集流体32的两侧分别设置正极材料30为例进行说明。涂层31设置在正极材料30和正极集流体32之间，且涂层31具有第二电阻R2。第二电阻R2满足：20mΩ≤R2≤1000mΩ，且涂层的厚度H满足：0.5μm≤H≤5μm。例如，参考图2，涂层31可以作为正极极片02的安全涂层，以保护正极集流体32的表面。例如，涂层31的设置可以增加正极集流体32与电池中的负极之间的阻值，从而减少正极集流体32与负极发生内短路时的电流和产热，以降低温升。因此，当电池发生针刺等机械滥用时，涂层31的设置可以在电池负极与正极集流体32发生接触时，将电池的短路点的温度控制在正极材料30的热失控温度以下，从而避免电池发生热失控。
例如，参考图2，涂层31的厚度可以满足：1μm≤H≤3μm，以利于控制正极集流体32与电池中的负极之间的阻值，将电池的短路点的温度控制在正极材料30的热失控温度以下，从而避免电池发生热失控。
例如，参考图2，涂层31的第二电阻可以满足：10mΩ≤R2≤300mΩ，以利于将电池的短路点的温度控制在正极材料30的热失控温度以下，减小电池发生热失控的概率。
例如，正极集流体32可以不同于上述实施例中的复合集流体。例如，正极集流体32可采用金属材料，例如铝箔，但不限于此。
例如，涂层的材料包括无机材料、导电剂以及粘结剂，但不限于此。
例如，无机材料可以包括磷酸铁锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、富锂锰基材料、镍钴铝酸锂、钛酸锂中的至少一种，但不限于此。例如，导电剂可以包括炭黑、碳纤维、碳纳米管、石墨、石墨烯、金属粉末、导电聚合物、导电陶瓷粉末中的至少一种，但不限于此。例如，粘结剂可以包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、羧甲基纤维素锂中的至少一种，但不限于此。
例如，对于无机材料的选取可以根据实际的设计需求进行确定，以针对不同电池的短路点温度进行有效控制，提高热稳定性，本公开的实施例对此不作限定。
本公开的一些实施例还提供一种电池，该电池包括上述任一实施例中的正极极片。例如，本公开的实施例提供的电池可以为锂离子电池，但不限于此。例如，本公开的实施例提供的电池中，正极极片可以为上述实施例中的正极极片01或正极极片02，关于该电池中的正极极片的各向组成参数请参考上述相关说明，在此不作赘述。
在本公开的实施例提供的电池中，通过在热稳定性较低的第一组分中掺混热稳定性较高的第二组分，可使得正极极片在具有较高的能量密度的同时，提高热稳定性，以减小热失控发生的概率，具有较高的安全性能。
本公开的实施例还提供一种装置，该装置包括上述任一实施例中所提供的电池，且电池被配置为该装置的电源。
例如，本公开的实施例提供的装置可以汽车，例如电动汽车。例如，电动汽车可以为电动纯电动车、混合动力电动车、插电式混合动力电动车中的任意一种，但不限于此。例如，电动汽车可以为电动大巴、电动有轨电车、电动自行车、电动摩托车、电动踏板车、电动高尔夫球车、电动卡车中的任意一种，但不限于此。例如，本公开的实施例提供的装置还可以为电动船舶、电动工具、电子设备及储能系统中的任意一种，但不限于此。
在本公开的实施例提供的装置中，对于设置在该装置中的电池，通过在热稳定性较低的第一组分中掺混热稳定性较高的第二组分可使得正极极片在具有较高的能量密度的同时，提高热稳定性，以减小热失控发生的概率，具有较高的安全性能，并利于获得大容量的电池。
本公开的至少一个实施例还提供一种用于电池的正极极片的制备方法。该 制备方法包括：形成含有正极材料的正极材料层。
在形成含有正极材料的正极材料层时的步骤包括：在第一组分中掺混第二组分，以制备正极材料。此时，第一组分的热稳定性低于第二组分的热稳定性，且正极材料满足：
τ＝T1*(8-lgCap)/(2256*w)
w为第一组分占正极材料层的质量比例，T1为第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为电池的容量，Cap单位为A·h，τ为正极材料的特性比值。
在制备该正极极片时，需满足：0.8≤τ≤1.5。
通过上述方法制作的正极极片，利于获得大容量的电池，并降低在电池发生机械滥用时出现热失控的概率。
在制备正极极片的正极材料层时，通过合理地选取第一组分和第二组分，使得在热稳定性较低的第一组分中掺混热稳定性较高的第二组分，可以降低电池出现产热、释氧等情况，以及在电池发生机械滥用时出现热失控的概率。同时，还可以使得该正极材料应用于较大电容量需求的场景，例如可以应用于容量大于10A·h的动力类或储能类的锂离子电池，以满足较大的电池容量需求。例如，电池的容量大于或等于100A·h。进一步例如，电池的容量大于或等于100A·h，并且小于或等于115A·h，但不限于此。
通过该制备方法所制备的正极极片，可以使电池在拥有较高的安全性能的同时，能够满足较大的容量需求，以具有较大的应用潜力。
例如，在本公开的一些实施例中，在制备正极极片的正极材料层时，在电池容量给定的情况下，可以通过调整电池的容量、正极材料中的组分和含量，使得正极材料满足：0.85≤τ≤1.2。从而，可以使得采用该正极材料的电池具有较好的安全性能，以及较大的电池容量。
例如，在本公开的一些实施例中，在制备正极极片的正极材料层时，可以通过调整电池的容量、正极材料中第一组分和第二组分含量，使得正极材料满足：0.9≤τ≤1.1。从而，可以使得采用该正极材料的电池具有更好的安全性能，以及更大的电池容量。
例如，在本公开的一些实施例中，在制备正极极片的正极材料层时，可以使得正极材料中第一组分在差示扫描量热法表征中的放热峰值处的温度小于 或等于306℃，第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃，但不限于此。通过以差示扫描量热法表征中的放热峰值处的温度为306℃作为分界，来区分正极材料中的两个组分，利于正极材料组分的选择和含量的获得。
例如，通过使得第一组分的热稳定性低于第二组分的热稳定性，则第一组分在单位时间内产生的热效应高于第二组分在单位时间内产生的热效应。例如，可以使得第一组分和第二组分的放热峰值温度界限为306℃。由此，通过将第二组分与第一组分进行掺混，可以使得正极极片01的正极材料的热稳定性得到改善，以使得电池具有较高的安全性。关于各组分在差示扫描量热法表征中的放热峰值处的温度的特点和获取方式可参见上述实施例中的相关说明，在此不作赘述。
例如，在本公开的一些实施例中，在制备正极极片的正极材料层时，可以使得正极材料中第一组分的克容量大于或等于150mA·h/g，第二组分的克容量小于150mA·h/g，但不限于此。通过对正极活性材料组分的克容量进行进一步限定，进一步筛选正极活性材料，使得第一组分和第二组分的界限更加明晰。关于各组分的克容量的确定方法可参见上述实施例中的相关说明，在此不作赘述。
例如，在制备正极极片的正极材料层时，可以使得第一组分的能量密度大于第二组分的能量密度，且第一组分与第二组分的克容量以150mA·h/g为界限。由此，通过将第一组分与第二组分掺混，可以使得正极极片01的正极材料的整体能量密度得到改善，以使得电池具有较高的能量密度。
例如，在本公开的一些实施例中，该正极极片的制备方法还可以包括如下步骤。
步骤(1)、在正极集流体的至少一侧涂布涂层材料。
步骤(2)、将正极材料层设置在涂层材料的远离正极集流体的一侧，并进行干燥处理。
步骤(3)、将经过干燥处理的正极极片进行冷压处理。
步骤(4)、将冷压后的正极极片分切后裁剪至规定尺寸。
例如，涂层材料的具体特征参数可参考上述实施例中的相关说明，在此不作赘述。由涂层材料形成的涂层可以在电池负极与正极集流体发生接触时，将 电池的短路点的温度控制在正极材料的热失控温度以下，从而避免电池发生热失控。
例如，对于本公开至少一个实施例所提供的电池，还可以包括负极极片和电解液。该电池的制备工艺可以包括下述步骤。
(1)正极极片的制备
例如，关于电池中的正极极片的制备方法可以参见上述实施例中的相关说明，在此不作赘述。根据正极极片的结构按序制作，形成正极极片。在正极极片不设置涂层的情况下，省略制作涂层的步骤。在正极极片的正极集流体不采用复合结构的情况下，采用对应结构的正极集流体替换复合结构的正极集流体。
(2)负极极片的制备
例如，电池中的负极极片可以包括负极集流体、负极材料层以及负极涂层。例如，可以将负极涂层设置在负极集流体的至少一侧，将负极材料层设置在负极涂层的远离负极集流体的一侧。例如，负极材料层可以包括负极材料。例如，负极材料可以包括负极活性物质，且负极活性物质的组分不受具体限制。例如，负极活性物质可以包括人造石墨、天然石墨、软碳、硬碳、中间相碳微球、硅基材料、锡基材料、钛酸锂中的至少之一。例如，负极涂层可以包括导电剂以及粘结剂，但不限于此。例如，负极集流体可以包括铜箔，但不限于此，可根据实际需求进行选择。
(3)电解液的制备
例如，电池中的电解液可以包括锂盐以及有机溶剂，但不限于此。例如，锂盐可以包括六氟磷酸锂、四氟硼酸锂、高氯酸锂中的至少一种。例如，有机溶剂可包括环状碳酸酯、链状碳酸酯、羧酸酯中的至少一种。例如，电解液中还可含有功能添加剂，例如碳酸亚乙烯酯、硫酸乙烯酯、丙磺酸内酯、氟代碳酸乙烯酯等，本公开的至少一个实施例对于电解液的材料不作限制。
(4)隔离膜层的制备
例如，电池的隔离膜层可以包括聚乙烯膜，但不限于此。
(5)电池的封装
例如，电池进行封装时可以首先将正极极片、隔离膜层以及负极极片依次层叠设置，并使得隔离膜层位于正极极片与负极极片之间。然后，可以将上述层叠设置后的结构卷绕以得到裸电芯。其次，将该裸电芯设置在电池的外包装 壳内，并进行干燥处理，进而注入上述电解液。最终，经过真空封装、静置、化成、整形等工序，得到电池。
针对本公开至少一个实施例所提供的电池，下面以实施例的形式对其进行说明。
例如，对于电池性能测试过程中，电池的正极极片01中的正极材料的第一组分为三元材料，第二组分为磷酸铁锂。例如，第一组分可以为不同镍含量的三元材料，例如，热失控温度为264℃的第一组分(三元材料)中镍含量为60％；例如，热失控温度为298℃的第一组分(三元材料)中镍含量为33％；热失控温度为225℃的第一组分(三元材料)中镍含量为80％。在该电池性能测试过程中，所采用的电池的正极集流体的第一电阻R1均为50mΩ。
例如，电池的负极极片中的负极材料包括石墨材料(例如，人造石墨或天然石墨)。例如，电池的容量可分别包括100A·h和115A·h。然后，针对上述配置的包括正极极片01的电池进行针刺测试。
例如，针刺测试方法可以包括：将电池以CC-CV的方式充满电后，用Φ5mm的耐高温钢针，以25±5mm/s的速度，从垂直于电池极板(例如正极极片01)的方向贯穿，使钢针停留在电池中1h。正极集流体的电阻采用50mΩ，电池容量为100A·h或115A·h。例如，针刺测试的方法可以参照GB/T 31486-2015，但不限于此。
实施例1
实施例1提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.70，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.003，电池的能量密度为218Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例2
实施例2提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.78，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.900，电池的能量密度为223 Wh/kg。针对该电池的针刺结果为：9/10p，也即在10次针刺试验中，9次试验结果均合格。
实施例3
实施例3提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.64，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.097，电池的能量密度为213Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例4
实施例4提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.82，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.856，电池的能量密度为226Wh/kg。针对该电池的针刺结果为：8/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例5
实施例5提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.59，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.190，电池的能量密度为210Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例6
实施例6提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.87，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.807，电池的能量密度为229Wh/kg。针对该电池的针刺结果为：7/10p，也即在10次针刺试验中，7次试验结果均合格。
实施例7
实施例7提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.47，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.494，电池的能量密度为201Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例8
实施例8提供的正极极片中，第一组分为镍含量为33％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.78，第一组分在差示扫描量热法表征中的放热峰值处的温度为298℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.016，电池的能量密度为223Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例9
实施例9提供的正极极片中，第一组分为镍含量为80％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.58，第一组分在差示扫描量热法表征中的放热峰值处的温度为225℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.032，电池的能量密度为209Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例10
实施例10提供的正极极片中，第一组分为镍含量为33％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.73，第一组分在差示扫描量热法表征中的放热峰值处的温度为298℃，电池的容量为115A·h，该电池的正极极片的正极材料的特性比值τ为1.075，电池的能量密度为223Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。
实施例11
实施例11提供的正极极片中，第一组分为镍含量为60％的三元材料，第 二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.95，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.739，电池的能量密度为235Wh/kg。针对该电池的针刺结果为：0/10p，也即在10次针刺试验中，10次试验结果均不合格。
实施例12
实施例12提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.35，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为2.006，电池的能量密度为193Wh/kg。针对该电池的针刺结果为：10/10p，也即在10次针刺试验中，10次试验结果均合格。表1示出了的实施例1-实施例12及对应参数及测试结果。
表1：针对包括正极极片01的电池进行针刺测试的结果
例如，根据表1可知，当正极材料满足：τ＝T1*(8-lgCap)/(2256*w)，且当 0.8≤τ≤1.5时，正极材料通过针刺测试的概率最低为70％。当0.85≤τ≤1.2时，正极材料通过针刺测试的概率最低为80％。0.9≤τ≤1.1时，正极材料通过针刺测试的概率最低为90％。例如，在本公开的实施例中，正极材料中的τ所满足的数值范围，可以具有一定的波动范围，例如，该波动范围可以为0.5％～0.1％，但不限于此。
例如，根据实施例1-实施例7可知，随着τ的不断增大，电池的能量密度呈降低趋势。例如，根据实施例11，当τ过低时，电池的针刺试验结果变差。例如，根据实施例12，当τ过高时，电池的能量密度变低。因此，为使得电池的安全性能较好，且能量密度较高时，需使得τ位于合理的范围内。
下述实施例中，采用正极极片02进行试验。针对正极极片02进行试验时，第一组分采用镍含量不同的三元材料，第二组分采用磷酸铁锂，关于不同镍含量所对应的差示扫描量热法表征中的放热峰值处的温度可参见上述实施例中的相关说明在此不作重复。正极极片02中的正极集流体采用铝箔，正极极片02中的涂层31的材料为磷酸铁锂，且涂层31的第二电阻为20mΩ。电池的容量可分别包括100A·h和115A·h。然后，针对上述配置的包括正极极片02的电池进行针刺测试。
实施例13
实施例13提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.70，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.003，电池的能量密度为221Wh/kg。针对该电池的针刺结果为：10/10p。
实施例14
实施例14提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.78，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.900，电池的能量密度为226Wh/kg。针对该电池的针刺结果为：8/10p。
实施例15
实施例15提供的正极极片中，第一组分为镍含量为60％的三元材料，第 二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.64，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.097，电池的能量密度为216Wh/kg。针对该电池的针刺结果为：10/10p。
实施例16
实施例16提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.82，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.856，电池的能量密度为229Wh/kg。针对该电池的针刺结果为：7/10p。
实施例17
实施例17提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.59，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.190，电池的能量密度为213Wh/kg。针对该电池的针刺结果为：10/10p。
实施例18
实施例18提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.87，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.807，电池的能量密度为232Wh/kg。针对该电池的针刺结果为：6/10p。
实施例19
实施例19提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.47，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.494，电池的能量密度为204Wh/kg。针对该电池的针刺结果为：10/10p。
实施例20
实施例20提供的正极极片中，第一组分为镍含量为33％的三元材料，第 二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.78，第一组分在差示扫描量热法表征中的放热峰值处的温度为298℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.016，电池的能量密度为226Wh/kg。针对该电池的针刺结果为：10/10p。
实施例21
实施例21提供的正极极片中，第一组分为镍含量为80％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.58，第一组分在差示扫描量热法表征中的放热峰值处的温度为225℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为1.032，电池的能量密度为212Wh/kg。针对该电池的针刺结果为：10/10p。
实施例22
实施例22提供的正极极片中，第一组分为镍含量为33％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.73，第一组分在差示扫描量热法表征中的放热峰值处的温度为298℃，电池的容量为115A·h，该电池的正极极片的正极材料的特性比值τ为1.075，电池的能量密度为226Wh/kg。针对该电池的针刺结果为：10/10p。
实施例23
实施例23提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.95，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为0.739，电池的能量密度为238Wh/kg。针对该电池的针刺结果为：0/10p。
实施例24
实施例24提供的正极极片中，第一组分为镍含量为60％的三元材料，第二组分为磷酸铁锂，第一组分占正极材料层的质量比例w为0.35，第一组分在差示扫描量热法表征中的放热峰值处的温度为264℃，电池的容量为100A·h，该电池的正极极片的正极材料的特性比值τ为2.006，电池的能量密度为196Wh/kg。针对该电池的针刺结果为：10/10p。
例如，表2示出了针对包括正极极片02的电池进行针刺测试的结果。
表2：针对包括正极极片02的电池进行针刺测试的结果
参考表2，根据实施例13-实施例22可知，当0.8≤τ≤1.5时，电池均有较大概率通过针刺试验。当1≤τ≤1.5时，电池通过针刺试验的概率较高。例如，在实施例23中，τ小于0.8，电池几乎无法通过针刺试验。例如，在实施例24中，τ大于0.8，电池虽然可以通过针刺试验，但是将导致电池的能量密度降低。
因此，正极极片02中设置有涂层31，可以使得正极集流体与电池中的负极之间的阻值增加，从而减少正极集流体与负极发生内短路时的电流和产热，以降低温升。同时，由于正极极片02中还采用了符合要求的正极材料，即正极材料的特性比值0.8≤τ≤1.5时，可以使得该电池的能量密度保持在较高水平。
由此，本公开的实施例所提供的正极极片，可以使电池在拥有较高的安全性能的同时，能够满足较大的容量需求，以具有较大的应用潜力。
在不冲突的情况下，本公开的同一实施例及不同实施例中的特征可以相互组合。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应 以所述权利要求的保护范围为准。

Claims (23)

  1. 一种用于电池的正极极片，包括：含有正极材料的正极材料层，
    所述正极材料包括第一组分和第二组分，所述第一组分的热稳定性低于所述第二组分的热稳定性，所述正极材料满足：
    τ＝T1*(8-lgCap)/(2256*w)
    w为所述第一组分占所述正极材料层的质量比例，T1为所述第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为所述电池的容量，Cap单位为A·h，τ为所述正极材料的特性比值，
    其中，0.8≤τ≤1.5。
  2. 根据权利要求1所述的用于电池的正极极片，其中，0.85≤τ≤1.2。
  3. 根据权利要求1所述的用于电池的正极极片，其中，0.9≤τ≤1.1。
  4. 根据权利要求1-3任一项所述的用于电池的正极极片，其中，所述第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，所述第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃。
  5. 根据权利要求1-4任一项所述的用于电池的正极极片，其中，所述第一组分的克容量大于或等于150mA·h/g，所述第二组分的克容量小于150mA·h/g。
  6. 根据权利要求1-5任一项所述的用于电池的正极极片，其中，所述第一组分包括三元材料、钴酸锂、镍酸锂中的至少一种，
    所述第二组分包括橄榄石材料、尖晶石材料和低镍含量的三元层状化合物中的至少一种，所述低镍含量的三元层状化合物中镍的质量百分比为30％-80％。
  7. 根据权利要求6所述的用于电池的正极极片，其中，所述橄榄石材料包括磷酸铁锂、磷酸锰铁锂、磷酸钒锂、锰酸锂中的至少之一。
  8. 根据权利要求1-7任一项所述的用于电池的正极极片，还包括正极集流体，所述正极集流体的至少一侧设有所述正极材料层。
  9. 根据权利要求8所述的用于电池的正极极片，其中，所述正极集流体为复合集流体，所述正极集流体具有第一电阻R1，所述第一电阻R1满足：20mΩ≤R1≤100mΩ。
  10. 根据权利要求8或9所述的用于电池的正极极片，还包括涂层，所述涂层位于所述正极材料层和所述正极集流体之间，所述涂层具有第二电阻R2，
    其中，所述第二电阻R2满足：20mΩ≤R2≤1000mΩ，且所述涂层的厚度H满足：0.5μm≤H≤5μm。
  11. 根据权利要求10所述的用于电池的正极极片，其中，所述涂层的厚度H满足：1μm≤H≤3μm。
  12. 根据权利要求10或11所述的用于电池的正极极片，其中，所述涂层的第二电阻R2满足：10mΩ≤R2≤300mΩ。
  13. 根据权利要求10-12任一项所述的用于电池的正极极片，其中，所述涂层的材料包括无机材料、导电剂以及粘结剂，
    所述无机材料包括磷酸铁锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、富锂锰基材料、镍钴铝酸锂、钛酸锂中的至少一种；
    所述导电剂包括炭黑、碳纤维、碳纳米管、石墨、石墨烯、金属粉末、导电聚合物、导电陶瓷粉末中的至少一种；
    所述粘结剂包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素钠、羧甲基纤维素锂中的至少一种。
  14. 根据权利要求1-13任一项所述的用于电池的正极极片，其中，所述电池的容量大于10A·h。
  15. 根据权利要求1-14任一项所述的用于电池的正极极片，其中，所述电池的容量大于或等于100A·h。
  16. 根据权利要求1-15任一项所述的用于电池的正极极片，其中，所述电池的容量大于或等于100A·h，并且小于或等于115A·h。
  17. 一种电池，包括如权利要求1-16任一项所述的正极极片。
  18. 一种装置，包括如权利要求17所述的电池，所述电池被配置为作为所述装置的电源。
  19. 一种用于电池的正极极片的制备方法，包括：形成含有正极材料的正极材料层，
    形成含有正极材料的正极材料层包括：
    在第一组分中掺混第二组分，以制备正极材料，
    其中，所述第一组分的热稳定性低于所述第二组分的热稳定性，所述正极材料满足：
    τ＝T1*(8-lgCap)/(2256*w)
    w为所述第一组分占所述正极材料层的质量比例，T1为所述第一组分在差示扫描量热法表征中的放热峰值处的温度，T1的单位为℃，Cap为所述电池的容量，Cap单位为A·h，τ为所述正极材料的特性比值，
    其中，0.8≤τ≤1.5。
  20. 根据权利要求19所述的制备方法，其中，0.85≤τ≤1.2。
  21. 根据权利要求19或20所述的制备方法，其中，0.9≤τ≤1.1。
  22. 根据权利要求19-21任一项所述的制备方法，其中，所述第一组分在差示扫描量热法表征中的放热峰值处的温度小于或等于306℃，所述第二组分在差示扫描量热法表征中的放热峰值处的温度大于306℃。
  23. 根据权利要求19-22任一项所述的制备方法，其中，所述第一组分的克容量大于或等于150mA·h/g，所述第二组分的克容量小于150mA·h/g。
PCT/CN2023/132181 2022-11-28 2023-11-17 用于电池的正极极片、电池、装置及制备方法 WO2024114403A1 (zh)

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