WO2021023138A1 - 正极极片及其相关的锂离子电池、装置 - Google Patents

正极极片及其相关的锂离子电池、装置 Download PDF

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Publication number
WO2021023138A1
WO2021023138A1 PCT/CN2020/106476 CN2020106476W WO2021023138A1 WO 2021023138 A1 WO2021023138 A1 WO 2021023138A1 CN 2020106476 W CN2020106476 W CN 2020106476W WO 2021023138 A1 WO2021023138 A1 WO 2021023138A1
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positive electrode
active material
membrane
current collector
ion battery
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PCT/CN2020/106476
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English (en)
French (fr)
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李星
王耀辉
金海族
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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 EP20849082.1A priority Critical patent/EP3989314A4/en
Publication of WO2021023138A1 publication Critical patent/WO2021023138A1/zh
Priority to US17/577,823 priority patent/US20220140345A1/en

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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

  • This application relates to the field of battery technology, and in particular to a positive pole piece and related lithium ion batteries and devices.
  • lithium-ion batteries As the energy density of lithium-ion batteries is further improved and the cost is further reduced, its application fields are becoming more and more extensive, especially in the fields of electric vehicles and energy storage.
  • safety performance is currently one of the main bottlenecks restricting the expansion of their application fields, because in the case of abuse, lithium-ion batteries with insufficient safety design may be thermally out of control, such as Smoke, fire or even explosion may occur, endangering personal and property safety.
  • the capacity of electric vehicles and energy storage batteries is much larger than that of consumer electronic products, and their capacity can usually reach dozens of Ah, or even hundreds of Ah, and the use conditions are more complicated than consumer electronic products, so their safety performance is more critical , Even seen as a technical bottleneck hindering its large-scale application.
  • Lithium-ion batteries using ternary materials as the positive electrode active materials have the characteristics of high energy density, but the ternary materials are usually poor in stability.
  • the needle puncture point When the nail penetration safety performance test is performed, the needle puncture point will be short-circuited and form a local hot zone. When the temperature exceeds the critical point, it will cause thermal runaway and fail to meet the standards for safe use.
  • the Chinese patent application CN103378352A with the filing date of April 25, 2012 discloses that a layer of lithium iron phosphate material coating is pre-coated on the positive electrode current collector to improve the protection of nickel cobalt lithium manganate, lithium manganate or lithium cobalt oxide batteries. Over discharge capability extends battery life. However, the patent fails to take into account the safety performance of the battery's nail penetration, and cannot make the battery reach the real safe use standard.
  • the purpose of this application is to provide a positive pole piece and its related lithium ion battery and device.
  • the positive pole piece can make the lithium ion battery have both high energy density and good nail penetration safety. Performance characteristics.
  • the present application provides a positive electrode sheet, which includes a positive electrode current collector, a first positive electrode membrane and a second positive electrode membrane.
  • the first positive electrode membrane is disposed on the positive electrode current collector and includes a first positive electrode active material, and the first positive electrode active material is selected from one of the phosphate materials LiFe 1-xy Mn x M y PO 4 or Several, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 0.1, 0 ⁇ x+y ⁇ 1, M is selected from one or more of Cr, Mg, Ti, Al, Zn, W, Nb, Zr, the
  • the second positive electrode membrane is disposed on the first positive electrode membrane and includes a second positive electrode active material, the gram capacity of the second positive electrode active material is higher than that of the first positive electrode active material, and the first positive electrode active material
  • the second positive electrode active material is different from the first positive electrode active material, and the thickness D0 of the positive electrode current collector is less than or equal to the thickness D1 of the first positive positive
  • the present application provides a lithium-ion battery, which includes the positive pole piece described in the first aspect of the present application.
  • the present application provides a device whose driving source or storage source is the lithium ion battery of the second aspect of the present application.
  • the positive electrode sheet of the present application includes two layers of positive electrode membranes.
  • the first positive electrode active material in the first positive electrode membrane is a highly stable phosphate material, and the gram capacity of the second positive electrode active material in the second positive electrode membrane is It is higher than the gram capacity of the first positive electrode active material; the second positive electrode membrane can ensure that the lithium ion battery has the characteristics of high energy density, and the first positive electrode membrane is in direct contact with the positive electrode current collector, which can effectively prevent penetration During the nailing process, the positive electrode current collector is in contact with the second positive electrode active material of high gram capacity, which weakens the embrittlement effect of the strong alkaline second positive electrode active material on the positive electrode current collector and reduces the generation of metal burrs during the nailing process.
  • the first positive electrode membrane can ensure that the lithium ion battery will not be caused by internal short circuit caused by the contact between the positive electrode current collector and the negative electrode membrane during the nailing process Severe thermal runaway; in addition, the thickness of the positive electrode current collector is less than or equal to the thickness of the first positive electrode membrane, which can more effectively prevent the metal burrs generated during the nailing process from contacting the negative electrode membrane.
  • the device of this application includes the lithium ion battery provided in this application, and therefore has at least the same advantages as the lithium ion battery of this application.
  • FIG. 1 is a schematic diagram of an embodiment of a lithium ion battery
  • Figure 2 is an exploded view of Figure 1;
  • Fig. 3 is a schematic diagram of an embodiment of a battery module
  • FIG. 4 is a schematic diagram of an embodiment of the battery pack
  • Figure 5 is an exploded view of Figure 4.
  • Fig. 6 is a schematic diagram of an embodiment of a device in which a lithium ion battery is used as a power source.
  • the positive electrode sheet according to the first aspect of the present application includes a positive electrode current collector, a first positive electrode membrane and a second positive electrode membrane.
  • the first positive electrode membrane is disposed on the positive electrode current collector and includes a first positive electrode active material, and the first positive electrode active material is selected from one of the phosphate materials LiFe 1-xy Mn x M y PO 4 or There are several, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 0.1, 0 ⁇ x+y ⁇ 1, and M is selected from one or more of Cr, Mg, Ti, Al, Zn, W, Nb, and Zr.
  • the second positive electrode membrane is disposed on the first positive electrode membrane and includes a second positive electrode active material, the gram capacity of the second positive electrode active material is higher than that of the first positive electrode active material, and The second positive electrode active material is different from the first positive electrode active material.
  • the first positive electrode membrane is arranged on one or both surfaces of the positive electrode current collector.
  • the first positive electrode membrane is arranged on both surfaces of the positive electrode current collector.
  • the second positive electrode active material is selected from lithium manganate, lithium-rich manganese-based materials, ternary materials Li 1+m Ni a Co b Me 1-ab O 2
  • -n Q n -0.1 ⁇ m ⁇ 0.2, 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1, 0 ⁇ 1-ab ⁇ 1, 0 ⁇ n ⁇ 0.1
  • Me is selected from Mn
  • Q is selected from one of F, Cl, S or Several
  • Lithium manganate, lithium-rich manganese-based materials, and ternary materials have the advantage of high gram capacity.
  • they can significantly increase the energy density of lithium-ion batteries.
  • the above-mentioned materials are usually more alkaline and are compatible with the positive electrode current collector. It is easy to make the positive electrode current collector brittle after direct contact. Therefore, more metal burrs will be generated during the nailing process of the lithium-ion battery. The place where the metal burrs are generated will generate a large amount of Joule heat due to a short circuit and form a local hot zone. When the temperature of the hot zone exceeds the critical temperature of the thermal runaway of the lithium-ion battery, it will cause the thermal runaway of the lithium-ion battery, causing smoke, fire or even explosion.
  • short circuit caused by the contact between the positive electrode current collector and the negative electrode current collector
  • short circuit caused by the contact between the positive electrode current collector and the negative electrode membrane
  • the contact between the positive electrode membrane and the negative electrode membrane Short circuit caused by the contact between the positive electrode diaphragm and the negative electrode current collector.
  • the short circuit caused by the contact between the positive electrode current collector and the negative electrode diaphragm is the most dangerous.
  • the short circuit resistance in this case is small, the current is large, and the resulting thermal power is high, and the heat conduction and The heat dissipation is relatively slow, and at the same time, the activity of the negative electrode active material is high, which is likely to cause a series of subsequent electrical and chemical reactions, leading to safety accidents.
  • the gram capacity of the positive electrode active material increases, its thermal stability will decrease, especially the thermal stability of high nickel materials will decrease significantly, which will also reduce the thermal runaway critical temperature of lithium-ion batteries, resulting in lithium-ion batteries’ The safety performance is further deteriorated.
  • lithium-rich manganese-based materials and ternary materials although the gram capacity of phosphate materials is relatively low, it has the advantages of abundant resources, low price, environmental friendliness, and stable discharge voltage.
  • the salt material also has the advantage of high stability.
  • As a positive electrode active material it will not make the positive electrode current collector brittle when it is in direct contact with the positive electrode current collector, so that excessive metal burrs will not be generated during the nailing process of the lithium ion battery. It can weaken the thermal runaway caused by the internal short circuit caused by the contact between the positive electrode current collector and the negative electrode diaphragm of the lithium ion battery, so that the lithium ion battery has better nail penetration safety performance.
  • the positive electrode sheet of the present application includes two layers of positive electrode membranes, namely, the first positive electrode membrane directly in contact with the positive electrode current collector and the second positive electrode membrane disposed on the first positive electrode membrane.
  • Positive diaphragm The first positive electrode active material in the first positive electrode membrane is a high-stability phosphate material, and the second positive electrode active material in the second positive electrode membrane is a high-gram capacity lithium manganate, lithium-rich manganese-based material, and Ternary materials.
  • the second positive electrode membrane can ensure that the lithium ion battery has the characteristics of high energy density, so as to meet the actual use requirements; while the first positive electrode membrane is in direct contact with the positive electrode current collector, on the one hand, it can effectively prevent the positive electrode current collector during the nailing process Contact with the second positive electrode active material of high gram capacity, weaken the embrittlement effect of the strong alkaline second positive electrode active material on the positive electrode current collector, reduce the generation of metal burrs during the nailing process, on the other hand, it can also prevent the nailing process The generated small amount of metal burrs contact with the negative electrode active material, so that the first positive electrode membrane can ensure that the lithium ion battery will not cause severe thermal runaway due to the internal short circuit caused by the contact between the positive electrode current collector and the negative electrode membrane during the nailing process. Therefore, the positive pole piece of the present application can enable the lithium ion battery to have high energy density and good nail penetration safety performance.
  • the thickness D0 of the positive electrode current collector is less than or equal to the thickness D1 of the first positive electrode film. If the thickness of the first positive electrode film is too small, smaller than the thickness of the positive electrode current collector, it cannot effectively prevent the metal burrs generated during the nailing process from contacting the negative electrode film, so it cannot effectively improve the nailing safety of the lithium ion battery performance.
  • the thickness D1 of the first positive electrode membrane is greater than the thickness D0 of the positive electrode current collector.
  • the thickness of the first positive electrode film is D1 satisfying: 6 ⁇ m ⁇ D1 ⁇ 21 ⁇ m.
  • the thickness of the second positive electrode membrane is D2 that satisfies: 50 ⁇ m ⁇ D2 ⁇ 200 ⁇ m.
  • the thickness of the first positive electrode membrane and the thickness of the second positive electrode membrane in this application refer to the thickness of the first positive electrode membrane and the second positive electrode membrane in the entire positive electrode sheet, that is, both include Both sides.
  • the thicker the first positive electrode film the better the safety performance of the lithium-ion battery, but the correspondingly greater impact on the energy density of the lithium-ion battery.
  • the nail penetration safety performance of the ion battery also does not affect the energy density of the lithium ion battery.
  • the thickness D1 of the first positive electrode membrane and the thickness D2 of the second positive electrode membrane satisfy the relationship: 70 ⁇ m ⁇ D2 -D1 ⁇ 170 ⁇ m.
  • the performance of the positive electrode current collector is also closely related to the nail penetration safety performance of the lithium ion battery.
  • the thickness of the positive electrode collector is too small, there may be a risk of band breakage during the production process of the positive pole piece, which will cause production failure. Go smoothly.
  • the thickness D0 of the positive electrode current collector satisfies: 5 ⁇ m ⁇ D0 ⁇ 20 ⁇ m.
  • the elongation at break of the positive current collector will also affect the nail penetration safety performance of the lithium ion battery. If the fracture elongation of the positive current collector is too large, the metal burrs formed on the positive current collector after nail penetration will be large, which is not conducive to improving the nail penetration safety performance of the lithium ion battery; if the fracture elongation of the positive current collector is too small, Its ductility is difficult to meet the processing requirements, and there will be a risk of band breaking during the processing of the positive pole piece or the charging and discharging process of the lithium ion battery, which is not conducive to the processing and production of the positive pole piece and the practical application of the lithium ion battery.
  • the elongation at break of the cathode current collector of the present application is tested in accordance with GB/T228-2008 "Metal Material Room Temperature Tensile Test Method".
  • the elongation at break ⁇ of the positive electrode current collector satisfies: 0.8% ⁇ 4%.
  • the metal burr formed on the positive electrode current collector after nailing also has a certain degree of ductility. If the metal burr contacts the negative electrode film The chip will short-circuit the battery internally and cause thermal runaway, which will deteriorate the nail penetration safety performance of the lithium-ion battery.
  • the thickness D0 of the positive electrode current collector and the thickness D1 of the first positive electrode membrane satisfy the relationship: D1 ⁇ (1+ ⁇ ) ⁇ D0.
  • the positive current collector is selected from aluminum foil.
  • the general formula of the lithium-rich manganese-based material may be zLi 2 MnO 3 ⁇ (1–z)LiM′O 2 , 0 ⁇ z ⁇ 1, M′ selected From one or more of Ni, Co, Mn.
  • the ternary material Li 1+m Ni a Co b Me 1-ab O 2-n Q n can be specifically selected from LiNi 1/3 Co 1/3 Mn 1/ 3 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.5 Co 0.25 Mn 0.25 O 2 , LiNi 0.55 Co 0.15 Mn 0.3 O 2 , LiNi 0.55 Co 0.1 Mn 0.35 O 2 , LiNi 0.55 Co 0.05 Mn 0.4 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.85 Co 0.05 Mn 0.1 O 2 , LiNi 0.88 Co 0.05 Mn 0.07 O 2 , LiNi 0.9 Co 0.05 Mn 0.05 One or more of O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , and
  • the lithium-ion battery can have a higher energy density while having better nail penetration safety performance.
  • LiFe 1-xy Mn x M y PO 4 may be specifically selected from one or more of LiFePO 4 , LiMnPO 4 , and LiFeMnPO 4 .
  • the mass of the first positive electrode active material is 5% of the total mass of the first positive electrode membrane.
  • the first positive electrode film further includes a first conductive agent and a first binder.
  • the types of the first conductive agent and the first adhesive are not specifically limited, and can be selected according to actual requirements.
  • the first conductive agent is selected from one or more of carbon black, acetylene black, SP carbon fiber, and carbon nanotube;
  • the first binder is selected from polyvinylidene fluoride, polytetrafluoroethylene One or more of ethylene and polyvinyl alcohol.
  • the content of the first conductive agent and the first binder is also not specifically limited, and can be selected according to actual requirements.
  • the mass of the first binder is more than 1% of the total mass of the first positive electrode membrane, so as to better enhance the bonding force between the first positive electrode membrane and the positive electrode current collector, and further improve The nail penetration safety performance of lithium-ion batteries.
  • the mass of the first conductive agent is more than 2% of the total mass of the first positive electrode membrane.
  • the mass of the second positive electrode active material is 97% of the total mass of the second positive electrode film.
  • the second positive electrode film further includes a second conductive agent and a second binder.
  • the types of the second conductive agent and the second adhesive are not specifically limited, and can be selected according to actual requirements.
  • the second conductive agent is selected from one or more of carbon black, acetylene black, SP carbon fiber, and carbon nanotube.
  • the second binder is selected from one or more of polyvinylidene fluoride, polytetrafluoroethylene, and polyvinyl alcohol.
  • the content of the second conductive agent and the second binder is also not specifically limited, and can be selected according to actual requirements.
  • the mass of the second binder is more than 1% of the total mass of the second positive electrode membrane.
  • the mass of the second conductive agent is more than 2% of the total mass of the second positive electrode membrane.
  • the lithium ion battery according to the second aspect of the present application includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • the positive pole piece is the positive pole piece according to the first aspect of the application.
  • the negative electrode sheet may include a negative electrode current collector and a negative electrode membrane arranged on the negative electrode current collector and comprising a negative electrode active material, and the negative electrode membrane may be arranged on the negative electrode.
  • One surface of the current collector can also be provided on both surfaces of the negative electrode current collector.
  • the type of the negative electrode active material is not specifically limited, and can be selected from graphite, soft carbon, hard carbon, mesophase carbon microspheres, carbon fibers, carbon nanotubes, elemental silicon, silicon oxygen compounds, silicon carbon composites , Silicon alloy, elemental tin, tin oxide compound, lithium titanate one or more.
  • the negative electrode film may also include a conductive agent and a binder, wherein the type and content of the conductive agent and the binder are not specifically limited, and can be selected according to actual requirements.
  • the type of the negative electrode current collector is not specifically limited, and can be selected according to actual needs.
  • the negative pole piece may also be metallic lithium or a lithium alloy.
  • the separator is arranged between the positive pole piece and the negative pole piece to play a role of isolation.
  • the type of the isolation film is not specifically limited, and it can be any isolation film material used in existing batteries, such as polyethylene, polypropylene, polyvinylidene fluoride and their multilayer composite film, but not limited to These ones.
  • the specific type of the electrolyte is not specifically limited, and may be a liquid electrolyte (also called an electrolyte) or a solid electrolyte.
  • the electrolyte uses a liquid electrolyte.
  • the liquid electrolyte may include electrolyte salts and organic solvents, and the types of electrolyte salts and organic solvents are not specifically limited, and can be selected according to actual needs.
  • the electrolyte may also include additives.
  • the types of additives are not particularly limited. They may be negative electrode film-forming additives, positive electrode film-forming additives, or additives that can improve certain performance of the battery, such as improving battery performance. Additives for charging performance, additives for improving battery high temperature performance, additives for improving battery low temperature performance, etc.
  • Fig. 1 shows a lithium-ion battery 5 with a square structure as an example.
  • the lithium-ion battery may include an outer package for packaging the positive pole piece, the negative pole piece, the separator, and the electrolyte.
  • the outer packaging of the lithium ion battery may be a soft bag, such as a pouch type soft bag.
  • the material of the soft bag can be plastic, for example, it can include one or more of polypropylene PP, polybutylene terephthalate PBT, polybutylene succinate PBS, and the like.
  • the outer packaging of the lithium-ion battery can also be a hard shell, such as a hard plastic shell, aluminum shell, steel shell, etc.
  • the outer package may include a housing 51 and a cover 53.
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the housing 51 has an opening communicating with the containing cavity, and a cover plate 53 can cover the opening to close the containing cavity.
  • the positive pole piece, the negative pole piece, and the separator may be formed into the cell 52 through a winding process or a lamination process.
  • the battery core 52 is encapsulated in the containing cavity.
  • the electrolyte is infiltrated in the cell 52.
  • the number of cells 52 contained in the lithium ion battery 5 can be one or several, which can be adjusted according to requirements.
  • lithium ion batteries can be assembled into battery modules, and the number of lithium ion batteries contained in the battery modules can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of lithium ion batteries 5 may be arranged in order along the length direction of the battery module 4. Of course, it can also be arranged in any other manner. Furthermore, the plurality of lithium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodation space, and a plurality of lithium ion batteries 5 are accommodated in the accommodation space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3.
  • the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4.
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the third aspect of the present application also provides a device, which includes the aforementioned lithium ion battery of the present application.
  • the lithium ion battery can be used as a power source of the device, and can also be used as an energy storage unit of the device.
  • the device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a lithium ion battery, battery module or battery pack according to its usage requirements.
  • Figure 6 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device usually requires light and thin, and can use lithium-ion batteries as a power source.
  • the lithium ion batteries of Examples 1-8 and Comparative Examples 1-2 were prepared according to the following methods.
  • the first positive electrode active material, the first conductive agent, and the first binder shown in Table 1 are uniformly mixed with the organic solvent N-methylpyrrolidone (NMP) in proportion to prepare the first positive electrode slurry, and then the first The positive electrode slurry was uniformly coated on one surface of the positive electrode current collector shown in Table 1, and the first positive electrode film was obtained after drying; the second positive electrode active material, the second conductive agent, and the second The binder is uniformly mixed with the organic solvent N-methylpyrrolidone (NMP) in proportion to prepare the second positive electrode slurry, and then the second positive electrode slurry is uniformly coated on the first positive electrode film, and the second positive electrode Two positive diaphragms.
  • NMP organic solvent N-methylpyrrolidone
  • the same operation is performed on the other surface of the positive electrode current collector, and finally the positive electrode pieces are obtained by cold pressing and slitting.
  • the negative active material, artificial graphite, binder styrene butadiene latex (SBR), conductive carbon black as a conductive agent, and solvent deionized water are mixed uniformly in a mass ratio of 90:5:5 to prepare a negative electrode slurry; then the negative electrode slurry is coated Cover the two surfaces of the negative electrode current collector copper foil, and obtain the negative electrode film after drying, and then cold press and slit to obtain the negative electrode electrode.
  • SBR styrene butadiene latex
  • a conventional polypropylene (PP) film is used as the isolation film.
  • the positive electrode sheet, the separator film, and the negative electrode sheet in order so that the separator film is located between the positive and negative electrode sheets for isolation, and then wind to obtain a bare cell; place the bare cell in the battery case, and then The electrolyte is injected, and then the lithium-ion battery is prepared through processes such as formation and standing.
  • the lithium ion batteries of Examples 1-8 have no fire or explosion phenomenon during nail penetration, and therefore have good nail penetration safety performance.
  • the lithium-ion battery will smoke after the nail is penetrated, but there is no spark or fire.
  • the lithium ion battery will spray out sparks after the nail is pierced. This is because the damage area of the steel needle becomes larger during the nail piercing process, and the probability of internal short circuit of the lithium ion battery increases, resulting in needle stick
  • the temperature at the port position increases, the gas production of the lithium-ion battery increases. When the gas accumulates to a certain extent, the internal pressure of the lithium-ion battery increases, and the explosion-proof valve is broken. With the protection of the first positive electrode film, the lithium ion battery will not catch fire or explode.
  • Comparative Example 1 since the structure of the positive pole piece is not protected by the first positive electrode film, the lithium ion battery will catch fire immediately when the nail is worn.
  • Comparative Example 2 although the structure of the positive pole piece is protected by the first positive electrode film, the thickness of the positive electrode film is smaller than the thickness of the positive electrode current collector, and the metal burr near the needle piercing hole and the negative electrode cannot be effectively prevented during the nailing process. The contact of the active material and the short circuit will generate a lot of heat at the moment of nail penetration, causing the lithium-ion battery to catch fire.
  • the positive pole piece of the present application can maintain a high energy density of the lithium ion battery while having good nail penetration safety performance.

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Abstract

一种正极极片及其相关的锂离子电池、装置，所述正极极片包括正极集流体、第一正极膜片以及第二正极膜片。所述第一正极膜片设置于所述正极集流体上且包括第一正极活性材料，所述第一正极活性材料选自磷酸盐材料LiFe 1-x-yMn xM yPO 4中的一种或几种，0≤x≤1，0≤y≤0.1，0≤x+y≤1，M选自Cr、Mg、Ti、Al、Zn、W、Nb、Zr中一种或几种，所述第二正极膜片设置于所述第一正极膜片上且包括第二正极活性材料，所述第二正极活性材料的克容量高于所述第一正极活性材料的克容量，且所述第二正极活性材料与所述第一正极活性材料不同，所述正极集流体的厚度D0小于等于所述第一正极膜片的厚度D1。所述正极极片可以使锂离子电池同时兼顾高能量密度以及良好的穿钉安全性能的特点。

Description

正极极片及其相关的锂离子电池、装置
本申请要求于2019年8月8日提交中国专利局、申请号为201910728944.3、申请名称为“正极极片及锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电池技术领域，尤其涉及一种正极极片及其相关的锂离子电池、装置。
背景技术
随着锂离子电池能量密度进一步提高、成本进一步降低，其应用领域越来越广泛，特别是在电动汽车和储能领域的应用被寄予厚望。然而，对于高能量密度的锂离子电池而言，安全性能是目前制约其应用领域扩展的主要瓶颈之一，因为在滥用的情况下，安全设计不足的锂离子电池会有热失控的可能，例如会发生冒烟、起火甚至是爆炸，危害人身和财产安全。通常电动汽车和能源存储电池的容量比消费电子产品大得多，其容量通常可以达到几十Ah，甚至上百Ah，且使用条件也比消费电子产品更为复杂，因此其安全性能更为关键，甚至被视为目前阻碍其大规模应用的技术瓶颈。
以三元材料作为正极活性材料的锂离子电池具有高能量密度的特点，但是三元材料通常稳定性差，在进行穿钉安全性能测试时，针刺点部位会发生短路并形成局部热区，当温度超过临界点时会引发热失控，达不到安全使用的标准。
申请日为2012年4月25日的中国专利申请CN103378352A公开了在正极集流体上预先涂上一层磷酸铁锂材料涂层改善了镍钴锰酸锂、锰酸锂或钴酸锂电池的防过放能力，延长了电池寿命。但是该专利未能兼顾电池的穿钉安全性能，不能使电池达到真正的安全使用标准。
发明内容
鉴于背景技术中存在的问题，本申请的目的在于提供一种正极极片及其相关的锂离子电池、装置，所述正极极片可以使锂离子电池同时兼顾高能量密度以及良好的穿钉安全性能的特点。
为了达到上述目的，在本申请的第一方面，本申请提供了一种正极极片，其包括正极集流体、第一正极膜片以及第二正极膜片。所述第一正极膜片设置于所述正极集流体上且包括第一正极活性材料，所述第一正极活性材料选自磷酸盐材料LiFe 1-x-yMn xM yPO 4中的一种或几种，0≤x≤1，0≤y≤0.1，0≤x+y≤1，M选自Cr、Mg、Ti、Al、Zn、W、Nb、Zr中一种或几种，所述第二正极膜片设置于所述第一正极膜片上且包括第二正极活性材料，所述第二正极活性材料的克容量高于所述第一正极活性材料的克容量，且所述第二正极活性材料与所述第一正极活性材料不同，所述正极集流体的厚度D0小于等于所述第一正极膜片的厚度D1。
在本申请的第二方面，本申请提供了一种锂离子电池，其包括本申请第一方面所述的正极极片。
在本申请的第三方面，本申请提供了一种装置，其驱动源或存储源为本申请第二方面的锂离子电池。
本申请至少包括下述的有益效果：
本申请的正极极片包括两层正极膜片，第一正极膜片中的第一正极活性材料为高稳定性的磷酸盐材料，而第二正极膜片中的第二正极活性材料的克容量高于所述第一正极活性材料的克容量；第二正极膜片可以保证锂离子电池具有高能量密度的特点，而第一正极膜片与正极集流体直接接触，一方面可以有效地阻止穿钉过程中正极集流体与高克容量的第二正极活性材料接触，减弱强碱性第二正极活性材料对正极集流体的脆化作用，减少穿钉过程中金属毛刺的产生，另一方面还可以阻止穿钉过程中产生的少量金属毛刺与负极活性材料接触，从而第一正极膜片可以保证锂离子电池在穿钉过程中不会因为正极集流体与负极膜片接触引发的内部短路而导致剧烈热失控；另外，正极集流体的厚度小于等于第一正极膜片的厚度，这样可以更有效地阻止穿钉过程中产生的金属毛刺与负极膜片的接触。
本申请的装置包括本申请提供的锂离子电池，因而至少具有与本申请锂离子电池相同的优势。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是锂离子电池的一实施方式的示意图；
图2是图1的分解图；
图3是电池模块的一实施方式的示意图；
图4是电池包的一实施方式的示意图；
图5是图4的分解图；
图6是锂离子电池用作电源的装置的一实施方式的示意图。
具体实施方式
下面详细说明根据本申请的正极极片及锂离子电池。
首先说明根据本申请第一方面的正极极片。
根据本申请第一方面的正极极片包括正极集流体、第一正极膜片以及第二正极膜片。所述第一正极膜片设置于所述正极集流体上且包括第一正极活性材料，所述第一正极活性材料选自磷酸盐材料LiFe 1-x-yMn xM yPO 4中的一种或几种，0≤x≤1，0≤y≤0.1，0≤x+y≤1，M选自Cr、Mg、Ti、Al、Zn、W、Nb、Zr中一种或几种。所述第二正极膜片设置于所述第一正极膜片上且包括第二正极活性材料，所述第二正极活性材料的克容量高于所述第一正极活性材料的克容量，且所述第二正极活性材料与所述第一正极活性材料不同。
其中，所述第一正极膜片设置于所述正极集流体的一个或两个表面上。可选地，所述第一正极膜片设置于所述正极集流体的两个表面上。
在本申请第一方面所述的正极极片中，所述第二正极活性材料选自锰酸锂、富锂锰基材料、三元材料Li 1+mNi aCo bMe 1-a-bO 2-nQ n中的一种或几种，-0.1≤m≤0.2，0<a<1，0<b<1，0<1-a-b<1，0≤n≤0.1，Me选自Mn、Al、Mg、Zn、 Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr、Sb、W、Mo中的一种或几种，Q选自F、Cl、S中的一种或几种；
锂离子电池的能量密度和穿钉安全性能与正极活性材料的种类和正极集流体的性质密切相关。锰酸锂、富锂锰基材料以及三元材料本身具有克容量高的优点，作为正极活性材料时可以显著地提高锂离子电池的能量密度，但是上述材料通常碱性较大，与正极集流体直接接触后极易使正极集流体变脆，因此在锂离子电池进行穿钉过程中会产生更多的金属毛刺，产生金属毛刺的地方会因为发生短路而产生大量的焦耳热形成局部热区，当热区的温度超过锂离子电池的热失控临界温度时将会引发锂离子电池热失控，发生冒烟、起火甚至是爆炸。
在锂离子电池的内部，短路的形式主要包括四种：正极集流体与负极集流体接触所引发的短路，正极集流体与负极膜片接触所引发的短路，正极膜片与负极膜片接触所引发的短路，正极膜片与负极集流体接触所引发的短路。其中，正极集流体和负极膜片之间接触所引发的短路是最危险的，原因在于这种情况下的短路电阻较小，电流较大，由此产生的热功率较高，而热量传导及散热又比较慢，同时负极活性材料的活性高，容易造成后续一系列的电反应及化学反应，以致酿成安全事故。另外，随着正极活性材料克容量的升高，其热稳定会降低，尤其是高镍材料的热稳定性明显降低，会使锂离子电池的热失控临界温度也降低，从而导致锂离子电池的安全性能进一步变差。
相比于锰酸锂、富锂锰基材料以及三元材料而言，虽然磷酸盐材料的克容量相对较低，但是其具有资源丰富、价格便宜、环境友好、放电电压稳定的优点，同时磷酸盐材料还具有稳定性高的优点，其作为正极活性材料直接与正极集流体接触时不会使正极集流体变脆，从而在锂离子电池穿钉过程中不会产生过多的金属毛刺，因此可以减弱锂离子电池因为正极集流体与负极膜片接触而导致内部短路所引发的热失控，使锂离子电池具有较好的穿钉安全性能。
综合考虑锂离子电池的能量密度和安全性能，本申请的正极极片包括两层正极膜片，即直接与正极集流体接触的第一正极膜片和设置于第一正极膜片上的第二正极膜片。其中第一正极膜片中的第一正极活性材料为高稳定性的磷酸盐材料，而第二正极膜片中的第二正极活性材料为高克容量的锰酸锂、富锂锰基材料以及三元材料。第二正极膜片可以保证锂离子电池具有高能量 密度的特点，从而满足实际的使用需求；而第一正极膜片与正极集流体直接接触，一方面可以有效地阻止穿钉过程中正极集流体与高克容量的第二正极活性材料接触，减弱强碱性第二正极活性材料对正极集流体的脆化作用，减少穿钉过程中金属毛刺的产生，另一方面还可以阻止穿钉过程中产生的少量金属毛刺与负极活性材料接触，从而第一正极膜片可以保证锂离子电池在穿钉过程中不会因为正极集流体与负极膜片接触引发的内部短路而导致剧烈热失控。因此本申请的正极极片可以使锂离子电池在具有高能量密度的同时还具有良好的穿钉安全性能。
在本申请第一方面所述的正极极片中，所述正极集流体的厚度D0小于等于所述第一正极膜片的厚度D1。若第一正极膜片的厚度过小，小于正极集流体的厚度，则其无法有效地阻止穿钉过程中产生的金属毛刺与负极膜片的接触，因此无法有效改善锂离子电池的穿钉安全性能。可选地，所述第一正极膜片的厚度D1大于所述正极集流体的厚度D0。
在本申请第一方面所述的正极极片中，可选地，所述第一正极膜片的厚度为D1满足：6μm≤D1≤21μm。
在本申请第一方面所述的正极极片中，可选地，所述第二正极膜片的厚度为D2满足：50μm≤D2≤200μm。
此处需要说明的是，本申请的第一正极膜片的厚度、第二正极膜片的厚度均是指整个正极极片中第一正极膜片、第二正极膜片的厚度，即均包括正反两个面。
在本申请第一方面所述的正极极片中，第一正极膜片越厚，锂离子电池的安全性能越好，但相应的其对锂离子电池能量密度的影响就越大，为了保证锂离子电池的穿钉安全性能同时也不影响锂离子电池的能量密度，可选地，所述第一正极膜片的厚度D1与所述第二正极膜片的厚度D2满足关系式：70μm≤D2-D1≤170μm。
在本申请第一方面所述的正极极片中，正极集流体的性能也与锂离子电池的穿钉安全性能密切相关，正极集流体的厚度越小，穿钉后正极集流体形成的金属毛刺就会越小，因此越有利于改善锂离子电池的穿钉安全性能，但是若正极集流体的厚度过小，则在正极极片的生产过程中可能出现断带的风险，从而会导致生产无法顺利进行。
可选地，所述正极集流体的厚度D0满足：5μm≤D0≤20μm。
在本申请第一方面所述的正极极片中，正极集流体的断裂延伸率也会对锂离子电池的穿钉安全性能产生影响。若正极集流体的断裂延伸率过大，则穿钉后正极集流体上形成的金属毛刺较大，不利于改善锂离子电池的穿钉安全性能；若正极集流体的断裂延伸率过小，则其延展性难以满足加工的要求，在正极极片的加工过程或锂离子电池的充放电过程中会出现断带的风险，不利于正极极片的加工生产和锂离子电池的实际应用。本申请的正极集流体的断裂延伸率按照GB/T228-2008《金属材料室温拉伸试验方法》进行测试。
可选地，所述正极集流体的断裂延伸率δ满足：0.8％≤δ≤4％。
在本申请第一方面所述的正极极片中，由于正极集流体具有一定的延展性，因此穿钉后正极集流体上形成的金属毛刺也具有一定的延展性，若金属毛刺接触到负极膜片则会使电池内部短路造成热失控，恶化锂离子电池的穿钉安全性能。
可选地，所述正极集流体的厚度D0与所述第一正极膜片的厚度D1满足关系式：D1≥(1+δ)×D0。此时可以避免穿钉后正极集流体上形成金属毛刺接触到负极膜片，即穿钉后正极集流体上形成的金属毛刺的长度不会超过第一正极膜片的厚度，进而锂离子电池具有较好的穿钉安全性能。
在本申请第一方面所述的正极极片中，所述正极集流体选自铝箔。
在本申请第一方面所述的正极极片中，所述富锂锰基材料的通式可为zLi 2MnO 3·(1–z)LiM′O 2，0≤z≤1，M′选自Ni、Co、Mn中的一种或几种。
在本申请第一方面所述的正极极片中，三元材料Li 1+mNi aCo bMe 1-a-bO 2-nQ n可具体选自LiNi 1/3Co 1/3Mn 1/3O 2、LiNi 0.5Co 0.2Mn 0.3O 2、LiNi 0.5Co 0.25Mn 0.25O 2、LiNi 0.55Co 0.15Mn 0.3O 2、LiNi 0.55Co 0.1Mn 0.35O 2、LiNi 0.55Co 0.05Mn 0.4O 2、LiNi 0.6Co 0.2Mn 0.2O 2、LiNi 0.75Co 0.1Mn 0.15O 2、LiNi 0.8Co 0.1Mn 0.1O 2、LiNi 0.85Co 0.05Mn 0.1O 2、LiNi 0.88Co 0.05Mn 0.07O 2、LiNi 0.9Co 0.05Mn 0.05O 2、LiNi 0.8Co 0.15Al 0.05O 2、LiNi 0.8Co 0.15Zr 0.05O 2中的一种或几种。
在本申请第一方面所述的正极极片中，在三元材料Li 1+mNi aCo bMe 1-a-bO 2- nQ n中，可选地，0.6≤a<1，0<b≤0.4，0<1-a-b≤0.4。此时锂离子电池可在具有较好的穿钉安全性能的同时具有更高的能量密度。
在本申请第一方面所述的正极极片中，可选地，LiFe 1-x-yMn xM yPO 4可具体 选自LiFePO 4、LiMnPO 4、LiFeMnPO 4中的一种或几种。
在本申请第一方面所述的正极极片中，可选地，所述第一正极活性材料的质量为所述第一正极膜片总质量的5％。
在本申请第一方面所述的正极极片中，所述第一正极膜片还包括第一导电剂和第一粘结剂。
其中，所述第一导电剂和第一粘结剂的种类没有具体的限制，可根据实际需求进行选择。可选地，所述第一导电剂选自炭黑、乙炔黑、SP碳纤维、碳纳米管中的一种或几种；所述第一粘结剂选自聚偏二氟乙烯，聚四氟乙烯，聚乙烯醇中的一种或几种。
所述第一导电剂和第一粘结剂的含量也没有具体的限制，可根据实际需求进行选择。可选地，所述第一粘结剂的质量为所述第一正极膜片总质量的1％以上，以更好地增强第一正极膜片与正极集流体之间的结合力，进一步提高锂离子电池的穿钉安全性能。可选地，所述第一导电剂的质量为所述第一正极膜片总质量的2％以上。
在本申请第一方面所述的正极极片中，可选地，所述第二正极活性材料的质量为所述第二正极膜片总质量的97％。
在本申请第一方面所述的正极极片中，所述第二正极膜片还包括第二导电剂和第二粘结剂。
其中，所述第二导电剂和第二粘结剂的种类没有具体的限制，可根据实际需求进行选择。可选地，所述第二导电剂选自炭黑、乙炔黑、SP碳纤维、碳纳米管中的一种或几种。可选地，所述第二粘结剂选自聚偏二氟乙烯，聚四氟乙烯，聚乙烯醇中的一种或几种。
所述第二导电剂和第二粘结剂的含量也没有具体的限制，可根据实际需求进行选择。可选地，所述第二粘结剂的质量为所述第二正极膜片总质量的1％以上。可选地，所述第二导电剂的质量为所述第二正极膜片总质量的2％以上。
其次说明根据本申请第二方面的锂离子电池。
根据本申请第二方面的锂离子电池包括正极极片、负极极片、隔离膜以及电解液。其中，所述正极极片为根据本申请第一方面所述的正极极片。
在本申请第二方面所述的锂离子电池中，所述负极极片可包括负极集流 体以及设置在负极集流体上且包括负极活性材料的负极膜片，所述负极膜片可设置在负极集流体的其中一个表面上也可以设置在负极集流体的两个表面上。
其中，所述负极活性材料的种类并不受到具体的限制，可选自石墨、软碳、硬碳、中间相碳微球、碳纤维、碳纳米管、单质硅、硅氧化合物、硅碳复合物、硅合金、单质锡、锡氧化合物、钛酸锂中的一种或几种。
所述负极膜片还可包括导电剂以及粘结剂，其中，导电剂以及粘结剂的种类和含量不受具体的限制，可根据实际需求进行选择。
所述负极集流体的种类也不受具体的限制，可根据实际需求进行选择。
在本申请第二方面所述的锂离子电池中，所述负极极片也可为金属锂或锂合金。
在本申请第二方面所述的锂离子电池中，所述隔离膜设置在正极极片和负极极片之间，起到隔离的作用。其中，所述隔离膜的种类并不受到具体的限制，可以是现有电池中使用的任何隔离膜材料，例如聚乙烯、聚丙烯、聚偏氟乙烯以及它们的多层复合膜，但不仅限于这些。
在本申请第二方面所述的锂离子电池中，所述电解液的具体种类并不受到具体的限制，可以为液体电解质(又称电解液)，也可以为固体电解质。可选地，所述电解质使用液体电解质。其中，所述液体电解质可包括电解质盐以及有机溶剂，电解质盐以及有机溶剂的种类均不受到具体的限制，可根据实际需求进行选择。所述电解质还可包括添加剂，所述添加剂的种类也没有特别的限制，可以为负极成膜添加剂，也可为正极成膜添加剂，也可以为能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温性能的添加剂等。
本申请对锂离子电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的锂离子电池5。
在一些实施例中，锂离子电池可包括外包装，用于封装正极极片、负极极片、隔离膜和电解液。
在一些实施例中，锂离子电池的外包装可以是软包，例如袋式软包。软包的材质可以是塑料，如可包括聚丙烯PP、聚对苯二甲酸丁二醇酯PBT、聚丁二酸丁二醇酯PBS等中的一种或几种。锂离子电池的外包装也可以是 硬壳，例如硬塑料壳、铝壳、钢壳等。
在一些实施例中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。
正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电芯52。电芯52封装于所述容纳腔。电解液浸润于电芯52中。
锂离子电池5所含电芯52的数量可以为一个或几个，可根据需求来调节。
在一些实施例中，锂离子电池可以组装成电池模块，电池模块所含锂离子电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个锂离子电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个锂离子电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个锂离子电池5容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
本申请第三方面还提供一种装置，所述装置包括本申请前述的锂离子电池。所述锂离子电池可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气 列车、船舶及卫星、储能系统等。
所述装置可根据其使用需求来选择锂离子电池、电池模块或电池包。
图6是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用锂离子电池作为电源。
下面结合实施例，进一步阐述本申请。应理解，这些实施例仅用于说明本申请而不用于限制本申请的范围。
实施例1-8和对比例1-2的锂离子电池均按照下述方法制备。
(1)正极极片的制备
将表1所示的第一正极活性材料、第一导电剂、第一粘结剂按比例与有机溶剂N-甲基吡咯烷酮(NMP)均匀混合后制备成第一正极浆料，然后将第一正极浆料均匀涂覆在表1所示的正极集流体的其中一个表面上，烘干后得到第一正极膜片；将表2所示的第二正极活性材料、第二导电剂、第二粘结剂按比例与有机溶剂N-甲基吡咯烷酮(NMP)均匀混合后制备成第二正极浆料，然后将第二正极浆料均匀涂覆在第一正极膜片上，烘干后得到第二正极膜片。
之后在正极集流体的另一个表面上进行相同的操作，最后经过冷压、分切即得到正极极片。
(2)负极极片的制备
将负极活性材料人造石墨、粘结剂丁苯胶乳(SBR)、导电剂导电碳黑按照质量比为90:5:5与溶剂去离子水混合均匀制备成负极浆料；然后将负极浆料涂覆在负极集流体铜箔的两个表面上，烘干后得到负极膜片，再经过冷压、分切即得到负极极片。
(3)电解液的制备
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比1:1:1进行混合得到有机溶剂，接着将充分干燥的LiPF 6溶解于混合后的有机溶剂中，配制成浓度为 1mol/L的电解液。
(4)隔离膜的制备
以常规的聚丙烯(PP)膜作为隔离膜。
(5)锂离子电池的制备
将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，然后卷绕得到裸电芯；将裸电芯置于电池壳体中，之后注入电解液，再经过化成、静置等工艺制得锂离子电池。
表1 实施例1-8和对比例1-2的正极集流体及第一正极膜片的参数设置
Figure PCTCN2020106476-appb-000001
表2 实施例1-8和对比例1-2的正极集流体及第二正极膜片的参数设置
Figure PCTCN2020106476-appb-000002
Figure PCTCN2020106476-appb-000003
接下来说明锂离子电池的测试过程。
锂离子电池的穿钉安全性能测试
先将锂离子电池进行满充，然后分别用直径Φ＝1mm和直径Φ＝3mm的耐高温钢针(针尖的圆锥角度为45°～60°，钢针表面光洁、无锈蚀、无氧化层、无油污)，以(25±5)mm/s的速度，从垂直于锂离子电池极板的方向贯穿锂离子电池，贯穿位置宜靠近所刺极板表面的几何中心，钢针停留在锂离子电池中，观察1h，不起火、不爆炸则表明锂离子电池通过了穿钉测试。
表3 实施例1-8和对比例1-2的性能测试结果
Figure PCTCN2020106476-appb-000004
Figure PCTCN2020106476-appb-000005
从表3的测试结果分析可知，实施例1-8的锂离子电池在穿钉过程中均无起火爆炸现象，因此具有良好的穿钉安全性能。当钢针的直径Φ＝1mm时，穿钉后锂离子电池会发生冒烟，但是没有火星、没有起火。当钢针的直径Φ＝3mm时，穿钉后锂离子电池会有火星喷出，这是因为穿钉过程中钢针的破坏面积变大，锂离子电池发生内部短路的几率增高，导致针刺口位置的温度升高，锂离子电池产气加剧，当气体积累到一定程度后，锂离子电池内部压力增大，防爆阀被冲破，高温气体遇到空气中的氧气会产生火星，但是因为有第一正极膜片的保护，锂离子电池并不会起火或者爆炸。
对比例1中，正极极片的结构中由于没有第一正极膜片的保护，穿钉时锂离子电池会立即起火。对比例2中，虽然正极极片的结构中有第一正极膜片的保护，但是正极膜片的厚度小于正极集流体的厚度，穿钉过程中不能有效阻止针刺口附近的金属毛刺与负极活性材料的接触，穿钉瞬间因短路会产生大量的热，导致锂离子电池起火。
由此可以看出，本申请的正极极片可以在使锂离子电池保持高能量密度的同时具有良好的穿钉安全性能。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (16)

  1. 一种正极极片，其中，包括正极集流体、第一正极膜片以及第二正极膜片；
    所述第一正极膜片设置于所述正极集流体上且包括第一正极活性材料，所述第一正极活性材料选自磷酸盐材料LiFe 1-x-yMn xM yPO 4中的一种或几种，0≤x≤1，0≤y≤0.1，0≤x+y≤1，M选自Cr、Mg、Ti、Al、Zn、W、Nb、Zr中一种或几种；
    所述第二正极膜片设置于所述第一正极膜片上且包括第二正极活性材料，所述第二正极活性材料的克容量高于所述第一正极活性材料的克容量，且所述第二正极活性材料与所述第一正极活性材料不同；
    所述正极集流体的厚度D0小于等于所述第一正极膜片的厚度D1。
  2. 根据权利要求1所述的正极极片，其中，
    所述第一正极膜片的厚度D1满足：6μm≤D1≤21μm；
    所述第二正极膜片的厚度D2满足：50μm≤D2≤200μm。
  3. 根据权利要求1或2所述的正极极片，其中，所述第一正极膜片的厚度D1与所述第二正极膜片的厚度D2满足关系式：70μm≤D2-D1≤170μm。
  4. 根据权利要求1-3任一项所述的正极极片，其中，所述正极集流体的厚度D0满足：5μm≤D0≤20μm。
  5. 根据权利要求1-4任一项所述的正极极片，其中，所述正极集流体的断裂延伸率δ满足：0.8％≤δ≤4％。
  6. 根据权利要求5所述的正极极片，其中，所述正极集流体的厚度D0与所述第一正极膜片的厚度D1满足关系式：D1≥(1+δ)×D0。
  7. 根据权利要求1-6任一项所述的正极极片，其中，所述第一正极活性材料的质量为所述第一正极膜片总质量的5％。
  8. 根据权利要求1-7任一项所述的正极极片，其中，所述第一正极膜片还包括第一导电剂和第一粘结剂，且所述第一粘结剂的质量为所述第一正极膜片总质量的1％以上，所述第一导电剂的质量为所述第一正极膜片总质量的2％以上。
  9. 根据权利要求1-8任一项所述的正极极片，其中，所述第一正极膜片设置于所述正极集流体的一个或两个表面上。
  10. 根据权利要求1-9任一项所述的正极极片，其中，所述第一正极膜片设置于所述正极集流体的两个表面上。
  11. 根据权利要求1-10任一项所述的正极极片，其中，所述第二正极活性材料的质量为所述第二正极膜片总质量的97％。
  12. 根据权利要求1-11任一项所述的正极极片，其中，所述第二正极膜片还包括第二导电剂和第二粘结剂，且所述第二粘结剂的质量为所述第二正极膜片总质量的1％以上，所述第二导电剂的质量为所述第二正极膜片总质量的2％以上。
  13. 根据权利要求1-12任一项所述的正极极片，其中，所述第二正极活性材料选自锰酸锂、富锂锰基材料、三元材料Li 1+mNi aCo bMe 1-a-bO 2-nQ n中的一种或几种，其中，-0.1≤m≤0.2，0<a<1，0<b<1，0<1-a-b<1，0≤n≤0.1，Me选自Mn、Al、Mg、Zn、Ga、Ba、Fe、Cr、Sn、V、Sc、Ti、Zr、Sb、W、Mo中的一种或几种，Q选自F、Cl、S中的一种或几种。
  14. 根据权利要求13所述的正极极片，其中，0.6≤a<1，0<b≤0.4，0<1-a-b≤0.4。
  15. 一种锂离子电池，其中，包括根据权利要求1至14中任一项所述的正极极片。
  16. 一种装置，其中，所述装置的驱动源或存储源为权利要求15所述的锂离子电池。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113314717A (zh) * 2021-05-26 2021-08-27 惠州亿纬锂能股份有限公司 一种复合集流体及其制备方法和应用

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113809278B (zh) * 2021-09-15 2023-05-16 珠海冠宇电池股份有限公司 一种电极组件及其应用
CN115403075A (zh) * 2022-08-16 2022-11-29 西南石油大学 一种无钴四元富锂锰基正极材料及其制备方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007035488A (ja) * 2005-07-28 2007-02-08 Sanyo Electric Co Ltd 非水電解質電池
CN103378352A (zh) 2012-04-25 2013-10-30 协鑫动力新材料（盐城）有限公司 锂离子电池正极极片及其制备方法
CN105098193A (zh) * 2015-09-24 2015-11-25 宁德时代新能源科技有限公司 正极片以及包括该正极片的锂离子电池
CN106663774A (zh) * 2014-09-08 2017-05-10 丰田自动车株式会社 非水电解质二次电池
CN109004175A (zh) * 2018-02-26 2018-12-14 宁德新能源科技有限公司 正极极片和锂离子电池
CN109461882A (zh) * 2018-11-05 2019-03-12 宁德新能源科技有限公司 正极极片、电化学装置及包含其的电子装置
CN109980181A (zh) * 2017-12-27 2019-07-05 财团法人工业技术研究院 锂离子电池用正极

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2535064A1 (fr) * 2006-02-01 2007-08-01 Hydro Quebec Materiau multi-couches, procede de fabrication et utilisation comme electrode
JP5156406B2 (ja) * 2007-01-18 2013-03-06 日立マクセルエナジー株式会社 リチウム二次電池用正極及びその製造方法、並びにリチウム二次電池
JP2012059472A (ja) * 2010-09-07 2012-03-22 Toyota Motor Corp 二次電池用電極の製造方法
JP2013062105A (ja) * 2011-09-13 2013-04-04 Hitachi Ltd リチウムイオン二次電池
CN103545559A (zh) * 2013-10-08 2014-01-29 宁德新能源科技有限公司 一种叠片式锂离子电池
JP6007942B2 (ja) * 2014-05-19 2016-10-19 トヨタ自動車株式会社 非水電解質二次電池およびその製造方法
CN105047937A (zh) * 2015-07-13 2015-11-11 曙鹏科技（深圳）有限公司 一种锂电池电芯及其制备方法
KR102167115B1 (ko) * 2016-07-07 2020-10-16 주식회사 엘지화학 이차전지용 전극 및 그러한 전극의 제조방법
KR102124950B1 (ko) * 2016-11-23 2020-06-22 주식회사 엘지화학 이차전지용 양극, 그 제조방법 및 이를 포함하는 리튬 이차전지
CN108511680B (zh) * 2017-02-24 2021-01-15 宁德时代新能源科技股份有限公司 正极片及其制备方法及储能装置
CN108963189A (zh) * 2017-05-17 2018-12-07 北京中友锂泰能源科技有限公司 一种高安全性的锂离子电池极片及其锂离子电池
CN109873166B (zh) * 2017-12-05 2021-06-29 宁德时代新能源科技股份有限公司 一种集流体，其极片和电化学装置
CN109873164B (zh) * 2017-12-05 2021-08-20 宁德时代新能源科技股份有限公司 一种集流体，其极片和电化学装置
CN109004171A (zh) * 2018-02-26 2018-12-14 宁德新能源科技有限公司 一种正极极片和锂离子电池
CN208298924U (zh) * 2018-04-27 2018-12-28 宁德新能源科技有限公司 极片以及电化学装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007035488A (ja) * 2005-07-28 2007-02-08 Sanyo Electric Co Ltd 非水電解質電池
CN103378352A (zh) 2012-04-25 2013-10-30 协鑫动力新材料（盐城）有限公司 锂离子电池正极极片及其制备方法
CN106663774A (zh) * 2014-09-08 2017-05-10 丰田自动车株式会社 非水电解质二次电池
CN105098193A (zh) * 2015-09-24 2015-11-25 宁德时代新能源科技有限公司 正极片以及包括该正极片的锂离子电池
CN109980181A (zh) * 2017-12-27 2019-07-05 财团法人工业技术研究院 锂离子电池用正极
CN109004175A (zh) * 2018-02-26 2018-12-14 宁德新能源科技有限公司 正极极片和锂离子电池
CN109461882A (zh) * 2018-11-05 2019-03-12 宁德新能源科技有限公司 正极极片、电化学装置及包含其的电子装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3989314A4

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113314717A (zh) * 2021-05-26 2021-08-27 惠州亿纬锂能股份有限公司 一种复合集流体及其制备方法和应用

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