WO2020177624A1 - 负极片、二次电池及其装置 - Google Patents

负极片、二次电池及其装置 Download PDF

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WO2020177624A1
WO2020177624A1 PCT/CN2020/077138 CN2020077138W WO2020177624A1 WO 2020177624 A1 WO2020177624 A1 WO 2020177624A1 CN 2020077138 W CN2020077138 W CN 2020077138W WO 2020177624 A1 WO2020177624 A1 WO 2020177624A1
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negative electrode
coating
silicon
mass percentage
based material
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PCT/CN2020/077138
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English (en)
French (fr)
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曾毓群
梁成都
闫传苗
柳金华
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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 ES20766158T priority Critical patent/ES2930297T3/es
Priority to EP20766158.8A priority patent/EP3916860B1/en
Publication of WO2020177624A1 publication Critical patent/WO2020177624A1/zh
Priority to US17/460,723 priority patent/US20210391572A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
    • H01M50/133—Thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes

Definitions

  • This application relates to the field of batteries, in particular to a negative electrode sheet, a secondary battery and a device thereof.
  • Silicon-based materials have attracted wide attention from researchers due to their high theoretical specific capacity (usually greater than 4200mAh/g) and abundant resources. However, silicon-based materials have a large volume expansion during the charging process. At the same time, silicon-based materials also have the problem of low initial charge and discharge efficiency, resulting in low initial charge and discharge efficiency of power batteries.
  • the purpose of this application is to provide a negative electrode sheet, a secondary battery and a device thereof, which can combine high specific energy, high first charge and discharge efficiency, good cycle performance, and safety. Features of good performance.
  • the present application provides a negative electrode sheet, which includes a negative electrode current collector and a negative electrode membrane arranged on the negative electrode current collector, the negative electrode membrane comprising a first coating Layer and second coating.
  • the first coating layer is located on the outermost layer of the negative electrode membrane and includes a first negative electrode active material
  • the first negative electrode active material includes a silicon-based material and a carbon material
  • the mass percentage of the silicon-based material is 0.5%-10%.
  • the second coating layer is disposed between the first coating layer and the negative electrode current collector and includes a second negative electrode active material.
  • the second negative electrode active material includes a silicon-based material and a carbon material. In the second coating, the mass percentage of the silicon-based material is 5%-50%.
  • the present application provides a secondary battery including the negative electrode sheet described in the first aspect of the present application.
  • this application relates to a device including the secondary battery described in the second aspect of this application.
  • the negative electrode sheet of the present application includes a negative electrode film having a multilayer structure, wherein the silicon-based material in the outer layer structure of the negative electrode film has a small mass percentage and the silicon in the inner layer structure
  • the mass percentage of the base material is large, so that the probability of breaking the SEI film on the surface of the negative electrode film during charging and discharging is greatly reduced.
  • the degree of ion irreversibility is also reduced, and the first charging and discharging efficiency and cycle performance of the secondary battery can be obtained.
  • the high content of silicon-based materials in the inner layer structure can ensure that the secondary battery has a high specific energy.
  • the device of the present application includes the secondary battery described in the second aspect of the present application, and thus has at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of an embodiment of the secondary battery of this application.
  • FIG. 2 is a schematic diagram of an embodiment of the battery module of this application.
  • FIG. 3 is a schematic diagram of an embodiment of the battery pack of this application.
  • Figure 4 is an exploded view of Figure 3;
  • FIG. 5 is a schematic diagram of an embodiment of a device using a secondary battery as a power source of this application;
  • the negative electrode sheet according to the first aspect of the present application includes a negative electrode current collector to provide a negative electrode membrane on the negative electrode current collector, and the negative electrode membrane includes a first coating layer and a second coating layer.
  • the first coating layer is located on the outermost layer of the negative electrode membrane and includes a first negative electrode active material
  • the first negative electrode active material includes a silicon-based material and a carbon material, and is in the first coating layer.
  • the mass percentage of the silicon-based material is 0.5%-10%.
  • the second coating layer is disposed between the first coating layer and the negative electrode current collector and includes a second negative electrode active material.
  • the second negative electrode active material includes a silicon-based material and a carbon material. In the second coating, the mass percentage of the silicon-based material is 5%-50%.
  • the specific energy of the secondary battery is closely related to the specific capacity of the negative electrode active material. Generally, the higher the specific capacity of the negative electrode active material, the more beneficial it is to increase the specific energy of the secondary battery.
  • the silicon-based material has a higher theoretical specific capacity, so it can achieve the purpose of increasing the specific energy of the secondary battery when used as the negative active material of the secondary battery. However, the silicon-based material expands greatly during the charging process, and the large expansion stress generated inside the silicon-based material will damage the structure of the silicon-based material.
  • This structural damage of the silicon-based material will not only damage the silicon-based material
  • the electrical contact with the silicon-based material may also cause the negative electrode membrane to fall off from the negative electrode current collector, making the extraction and insertion process of ions unable to proceed smoothly; and the irreversibility of the ion extraction and insertion process will increase. , Not only reduces the first charge and discharge efficiency of the secondary battery, but also affects the cycle performance and safety performance of the secondary battery.
  • the SEI film on the surface of the negative electrode membrane will continue to be broken and repaired, consuming a large amount of ions, resulting in an increasing degree of ion irreversibility, which will also affect the cycle of the secondary battery. performance.
  • the negative electrode film set on the negative electrode current collector of the present application has a multi-layer structure.
  • the first coating layer located on the outermost layer of the negative electrode film includes silicon-based materials and carbon materials.
  • the first coating layer is located between the first coating layer and the negative electrode current collector.
  • the second coating layer also includes silicon-based materials and carbon materials, but the difference is that the mass percentage of silicon-based materials in the first coating is less than the mass percentage of silicon-based materials in the second coating.
  • the secondary battery of the present application can have a higher specific energy; and compared with the single-layered silicon-based negative electrode sheet, the multilayer structure of the negative electrode film surface has a higher specific energy.
  • the higher the mass percentage of the silicon-based material the more beneficial it is to increase the specific energy of the secondary battery.
  • the SEI film on the surface of the negative electrode membrane is broken The probability increases, and as a result, the degree of ion irreversibility increases.
  • the mass percentage of silicon-based materials should not be too small, so that the expansion stress of the first coating and the second coating is likely to differ too much, and the interface compatibility between the first coating and the second coating will change. Poor, it will also affect the performance of the secondary battery.
  • the mass percentage of the silicon-based material is 0.5%-10%.
  • the mass percentage of the silicon-based material is 0.5% to 5%.
  • the higher the mass percentage of the silicon-based material the more beneficial it is to increase the specific energy of the secondary battery, but if the mass percentage of the silicon-based material is too large, the first coating and the second coating The expansion stress of the layers is too different, and the interface compatibility between the first coating and the second coating becomes poor, which will also affect the performance of the secondary battery.
  • the mass percentage of the silicon-based material is 5%-50%.
  • the mass percentage of the silicon-based material is 10%-40%.
  • both the first coating and the second coating contain silicon-based materials and carbon materials, the first coating and the second coating can have good interface compatibility, thereby Alleviate the problem of uneven expansion stress of the two coatings during charging.
  • the difference in mass percentage of the silicon-based material in the first coating and the second coating is too small, there is essentially no significant difference between it and the conventional single-layered negative electrode sheet, which will not reflect the multi-layer negative electrode film.
  • Advantages of structural design if the mass percentage of silicon-based materials in the first coating and the second coating differs too much, the difference in expansion stress between the first coating and the second coating will be too large.
  • the first coating and the second coating may be separated and demolded.
  • the difference between the mass percentage of the silicon-based material in the second coating and the mass percentage of the silicon-based material in the first coating is 5% to 35%. Further preferably, the difference between the mass percentage of the silicon-based material in the second coating and the mass percentage of the silicon-based material in the first coating is 10%-30%.
  • the difference in the mass percentage of the carbon material in the first coating and the second coating will also affect the performance of the secondary battery. If the difference in the mass percentage of the carbon material in the first coating and the second coating is too small, it will essentially have no significant difference compared with the conventional single-layered negative electrode sheet, thus failing to reflect the large number of negative electrode films. Advantages of layer structure design; if the mass percentage of carbon-based materials in the first coating and the second coating differs too much, it will cause the expansion stress between the first coating and the second coating to differ too much.
  • the first coating layer and the second coating layer may be separated and demolded.
  • the difference between the mass percentage of the carbon material in the first coating and the mass percentage of the carbon material in the second coating is 10%-40%. Further preferably, the difference between the mass percentage of the carbon material in the first coating and the mass percentage of the carbon material in the second coating is 10%-20%.
  • the thickness of the first coating layer is 20 ⁇ m to 80 ⁇ m. Further preferably, the thickness of the first coating layer is 20 ⁇ m-50 ⁇ m.
  • the thickness of the second coating layer is 40 ⁇ m to 140 ⁇ m. Further preferably, the thickness of the second coating layer is 60 ⁇ m-100 ⁇ m.
  • the ratio of the thickness of the first coating layer to the thickness of the second coating layer is 0.2-5. Further preferably, the ratio of the thickness of the first coating to the thickness of the second coating is 0.2-2. More preferably, the ratio of the thickness of the first coating to the thickness of the second coating is 0.5-1.
  • the negative electrode membrane further includes a miscible diffusion layer disposed between the first coating and the second coating, and the miscible diffusion layer passes through the first coating and the second coating.
  • the two coatings are formed by mutual dissolution and diffusion.
  • the existence of the miscible diffusion layer can further improve the interface compatibility between the first coating and the second coating, improve the bonding force between the first coating and the second coating, and prevent the second coating from changing from the first coating. The layer falls off, so that the safety performance of the secondary battery can be further improved.
  • the thickness of the miscible diffusion layer is 1 ⁇ m to 20 ⁇ m. Further preferably, the thickness of the miscible diffusion layer is 3 ⁇ m-10 ⁇ m.
  • the silicon-based material may be selected from one or more of amorphous silicon, crystalline silicon, silicon-carbon composites, silicon-oxygen compounds, and silicon alloys.
  • the carbon material It can be selected from one or more of artificial graphite, natural graphite, and mesophase carbon microspheres.
  • the sum of the mass percentages of the silicon-based material and the carbon material is 89.5% to 99%.
  • the sum of the mass percentages of the silicon-based material and the carbon material is 87% to 98%.
  • both the first coating layer and the second coating layer may further include a binder and a conductive agent, wherein the types of the binder and the conductive agent and There is no specific limit on the content and can be selected according to actual needs.
  • the adhesive in the first coating layer and the adhesive in the second coating layer may be the same or different.
  • the binder in the first coating layer is the same as the binder in the second coating layer, so that the first coating layer and the second coating layer can better dissolve and diffuse to form a miscible diffusion layer.
  • the mass percentage of the binder in the first coating layer is 0.5%-8%.
  • the mass percentage of the conductive agent is 0.5% to 2.5%.
  • the mass percentage of the binder is 1%-10%.
  • the mass percentage of the conductive agent is 1% to 3%.
  • the binder may be selected from one or more of polyacrylic acid, sodium polyacrylate, sodium alginate, polyacrylonitrile, polyethylene glycol, and carboxymethyl chitosan.
  • the conductive agent may be selected from one or more of acetylene black, Ketjen black, conductive carbon black, and carbon nanotubes.
  • the preparation method of the negative electrode sheet may include the steps:
  • Preparation of the first negative electrode slurry disperse the silicon-based material, carbon material, binder and conductive agent in deionized water in a certain proportion, and stir for 0.5h-8h;
  • the secondary battery according to the second aspect of the present application includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator, wherein the negative electrode sheet is the negative electrode sheet according to the first aspect of the present application.
  • the type of the separator is not specifically limited, and can be any separator material used in existing secondary batteries, such as polyethylene, polypropylene, polyvinylidene fluoride Ethylene and their multilayer composite film, but not limited to these.
  • the specific type and composition of the electrolyte are not subject to specific restrictions, and can be selected according to actual needs.
  • the secondary battery according to the second aspect of the present application may be a lithium ion battery, a sodium ion battery, or any other secondary battery using the negative electrode sheet described in the first aspect of the present application.
  • the secondary battery according to the second aspect of the present application is a lithium ion battery.
  • the positive electrode active material in the positive electrode sheet may be selected from one or more of lithium transition metal composite oxides, but the application is not limited thereto.
  • the positive electrode active material may be selected from one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide, and lithium iron phosphate.
  • the secondary battery may include an outer package for packaging the positive pole piece, the negative pole piece, and the electrolyte.
  • the positive pole piece, the negative pole piece and the separator can be laminated or wound to form a laminated structure electrode assembly or a wound structure electrode assembly, the electrode assembly is packaged in an outer package; the electrolyte can be an electrolyte, which is infiltrated In the electrode assembly.
  • the number of electrode assemblies in the secondary battery can be one or several, which can be adjusted according to requirements.
  • the outer packaging of the secondary battery may be a soft bag, such as a pouch type soft bag.
  • the material of the soft bag can be plastic, 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 electrochemical device can also be a hard shell, such as an aluminum shell.
  • Fig. 1 shows an electrochemical device 5 with a square structure as an example.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • Fig. 2 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in 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 secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodation space, and a plurality of secondary 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.
  • Figures 3 and 4 show the battery pack 1 as an example. 3 and 4, 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 device includes the secondary battery described in the second aspect of the present application.
  • the secondary battery provides power to 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 secondary battery, battery module, or battery pack according to its usage requirements.
  • Figure 5 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • battery packs or battery modules can be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device is generally required to be thin and light, and a secondary battery can be used as a power source.
  • the lithium ion batteries of Examples 1-12 and Comparative Examples 1-7 were prepared according to the following methods.
  • the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 , the conductive agent acetylene black, and the binder PVDF were mixed in a mass ratio of 96:2:2, and the solvent NMP was added, and the system was stirred under the action of a vacuum mixer until the system was uniform.
  • Positive electrode slurry The positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, dried at room temperature and transferred to an oven to continue drying, and then cold pressed and slit to obtain a positive electrode sheet.
  • the first negative electrode active material, binder, and conductive agent shown in Table 1 are mixed in proportions, and the solvent deionized water is added, and stirred until the system is uniform under the action of a vacuum mixer to obtain the first negative electrode slurry;
  • the second negative electrode active material, binder, and conductivity shown in 2 are mixed in proportion, solvent deionized water is added, and the system is stirred under the action of a vacuum mixer until the system is uniform to obtain a second negative electrode slurry; single-layer extrusion In this way, the second negative electrode slurry and the first negative electrode slurry are uniformly coated on the negative electrode current collector copper foil, dried at room temperature and transferred to an oven to continue drying, and then cold pressed and slit to obtain a negative electrode sheet.
  • Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then the fully dried lithium salt LiPF 6 is dissolved in the mixed
  • the latter organic solvent is formulated into an electrolyte with a concentration of 1 mol/L.
  • a polyethylene film is selected as the isolation film.
  • the lithium ion battery is charged to the upper limit voltage at a rate of 1/3C at room temperature, and then discharged to the lower limit voltage at a rate of 1/3C to obtain the energy during the discharge of the lithium ion battery.
  • the lithium-ion battery is converted to 3.75V at a small rate of 0.05C at room temperature, then charged to the upper limit voltage at a rate of 1/3C, and then discharged to the lower limit voltage at a rate of 1/3C to obtain the first charge capacity and the first charge of the lithium ion battery Discharge capacity.
  • the first charge and discharge efficiency of the lithium ion battery (%) the first discharge capacity of the lithium ion battery/the first charge capacity of the lithium ion battery ⁇ 100%.
  • the negative electrode films of Comparative Examples 1-3 are all arranged in a single-layer structure.
  • the negative electrode membrane of Comparative Example 1 only contains silicon-based materials and does not contain carbon materials.
  • the active specific surface area of the active lithium ion and Si contact reaction is large, and the negative electrode sheet generates serious heat.
  • the lithium ion battery has a higher specific energy, the lithium ion The first charge and discharge efficiency of the ion battery is poor, and the cycle performance of the lithium ion battery is poor; the negative electrode membrane of Comparative Example 2 only contains carbon materials and does not contain silicon-based materials.
  • the negative electrode membrane of Comparative Example 3 includes both carbon materials and silicon-based materials, although the heat generation of the negative electrode is similar to that of the comparative example. 1 Compared with lower, but its first charging and discharging efficiency is still low, it is difficult to meet the actual demand.
  • the first coating or the second coating cannot contain both silicon-based materials and carbon materials.
  • the interface compatibility becomes worse; and when the content of silicon-based materials and carbon materials in the first coating and the second coating is too large, the expansion stress of the first coating and the second coating during the charging process is different If it is too large, the interface compatibility between the first coating and the second coating will be further deteriorated, and the first coating will easily fall off.
  • the lithium ion battery cannot simultaneously take into account high specific energy, high first charge and discharge efficiency, and good cycle performance. This has affected the use of lithium-ion batteries.
  • the negative electrode film of Examples 1-12 has a multilayer structure, which includes a first coating layer located in the outermost layer and a second coating layer located between the first coating layer and the negative electrode current collector.
  • the content of silicon-based materials and carbon materials in the second coating is moderate.
  • the lithium ion battery has high specific energy and high first charge and discharge efficiency, and the lithium ion battery can also have good cycle performance.
  • the first coating and the second coating use different binders from Examples 1-9, and the lithium ion battery can still have high specific energy and high first charge and discharge. Efficiency, but also has good cycle performance.

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Abstract

本申请提供了一种负极片、二次电池及其装置。所述负极片包括负极集流体以及设置于所述负极集流体上的负极膜片，所述负极膜片包括第一涂层以及第二涂层。所述第一涂层位于所述负极膜片的最外层且包括第一负极活性材料，所述第一负极活性材料包括硅基材料和碳材料，且在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～10％。所述第二涂层设置于所述第一涂层和所述负极集流体之间且包括第二负极活性材料，所述第二负极活性材料包括硅基材料和碳材料，且在所述第二涂层中，所述硅基材料的质量百分含量为5％～50％。本申请的二次电池能兼具比能量高、首次充放电效率高、循环性能好以及安全性能好的特点。

Description

负极片、二次电池及其装置 技术领域
本申请涉及电池领域，尤其涉及一种负极片、二次电池及其装置。
背景技术
近些年，新能源汽车领域快速发展，动力电池受到了全球各大汽车厂商的关注与青睐。随着车企对动力电池比能量的要求越来越高，开发更高比能量的电极活性材料势在必行。常见的负极活性材料多以石墨为主，但其理论比容量仅为372mAh/g，且目前商业化的人造石墨和天然石墨的实际比容量已接近其理论比容量，无法进一步提高，从而限制了动力电池比能量的提升。因此，需要开发新的、具有更高比容量的负极活性材料。
硅基材料因具有较高的理论比容量(通常大于4200mAh/g)且资源丰富，而引起了研究者的广泛关注。然而，硅基材料在充电过程中体积膨胀较大，同时硅基材料还存在首次充放电效率偏低的问题，造成动力电池的首次充放电效率也偏低。
因此如何使包含硅基材料的动力电池也满足使用需求，是目前行业内普遍面临的难题。
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负极片、及二次电池及其装置，所述二次电池能兼具比能量高、首次充放电效率高、循环性能好以及安全性能好的特点。
为了达到上述目的，在本申请的第一方面，本申请提供了一种负极片，其包括负极集流体以及设置于所述负极集流体上的负极膜片，所述负极膜片包括第一涂层以及第二涂层。所述第一涂层位于所述负极膜片的最外层且包括第一负极活性材料，所述第一负极活性材料包括硅基材料和碳材料，且在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～10％。所述第二涂 层设置于所述第一涂层和所述负极集流体之间且包括第二负极活性材料，所述第二负极活性材料包括硅基材料和碳材料，且在所述第二涂层中，所述硅基材料的质量百分含量为5％～50％。
在本申请的第二方面，本申请提供了一种二次电池，其包括本申请第一方面所述的负极片。
在本申请的第三方面，本申请涉及一种装置，包括本申请第二方面所述的二次电池。
本申请至少包括如下所述的有益效果：本申请的负极片包括具有多层结构的负极膜片，其中负极膜片的外层结构中硅基材料的质量百分含量小、内层结构中硅基材料的质量百分含量大，这样负极膜片表面SEI膜在充放电过程中破碎概率大大降低，由此，离子不可逆程度也降低，进而二次电池的首次充放电效率以及循环性能可以得到很好地改善，内层结构中高含量的硅基材料可以保证二次电池具有高的比能量。本申请的装置包括本申请第二方面所述的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
图1为本申请的二次电池的一实施方式的示意图；
图2为本申请的电池模块的一实施方式的示意图；
图3为本申请的电池包的一实施方式的示意图；
图4是图3的分解图；
图5为本申请的二次电池作为电源的装置的一实施方式的示意图；
其中：
1-电池包；
2-上箱体；
3-下箱体；
4-电池模块；
5-二次电池。
具体实施方式
下面详细说明根据本申请的负极片、二次电池及其装置。
首先说明根据本申请第一方面的负极片。
根据本申请第一方面的负极片包括负极集流体以设置于所述负极集流体上的负极膜片，所述负极膜片包括第一涂层和第二涂层。其中，所述第一涂层位于所述负极膜片的最外层且包括第一负极活性材料，所述第一负极活性材料包括硅基材料和碳材料，且在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～10％。所述第二涂层设置于所述第一涂层和所述负极集流体之间且包括第二负极活性材料，所述第二负极活性材料包括硅基材料和碳材料，且在所述第二涂层中，所述硅基材料的质量百分含量为5％～50％。
二次电池的比能量与负极活性材料的比容量密切相关。通常，负极活性材料的比容量越高，越有利于提升二次电池的比能量。硅基材料由于具有较高的理论比容量，因此用作二次电池的负极活性材料时可以达到提高二次电池比能量的目的。但是硅基材料在充电过程中体积膨胀较大，由此硅基材料内部产生的较大膨胀应力会对硅基材料的结构造成破坏，这种硅基材料结构上的破坏不仅会破坏硅基材料与硅基材料之间的电接触，还可能会导致负极膜片从负极集流体上脱落，使离子的脱出和嵌入过程不能顺利进行；且离子在脱出和嵌入过程中的不可逆程度还会增大，不仅降低了二次电池的首次充放电效率，还影响了二次电池的循环性能和安全性能。同时由于硅基材料在充放电过程中体积膨胀较大，负极膜片表面的SEI膜会不断地破碎以及修复，消耗了大量离子，导致离子不可逆程度不断增大，也会影响二次电池的循环性能。
本申请设置于负极集流体上的负极膜片具有多层结构，位于负极膜片最外层的第一涂层包括硅基材料和碳材料，位于第一涂层与负极集流体之间的第二涂层也包括硅基材料和碳材料，但不同的是第一涂层中硅基材料的质量百分含量小于第二涂层中硅基材料的质量百分含量。与常规单层设置的碳基负极片相比，本申请的二次电池可具有更高的比能量；而与单层设置的硅基负极片相比，多层结构的负极膜片表面具有较低的硅基材料含量，这样二次电池充放电过程中，负极膜片表面SEI膜破碎概率大大降低，由此，离子不可逆程度也降低，进而二次电池的循环性能可以得到很好地改善。
在第一涂层中，硅基材料的质量百分含量越大，越有利于提升二次电池 的比能量，但是由于硅基材料在充电过程中体积膨胀较大，负极膜片表面SEI膜破碎概率升高，由此，离子不可逆程度升高。同时，硅基材料的质量百分含量也不宜过小，这样第一涂层和第二涂层承受的膨胀应力容易相差过大，进而第一涂层和第二涂层的界面相容性变差，也会影响二次电池的性能。
因此，在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～10％。优选地，在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～5％。
在第二涂层中，硅基材料的质量百分含量越大，越有利于提升二次电池的比能量，但是若硅基材料的质量百分含量过大，第一涂层和第二涂层承受的膨胀应力相差过大，第一涂层和第二涂层的界面相容性变差，也会影响二次电池的性能。
因此，在所述第二涂层中，所述硅基材料的质量百分含量为5％～50％。优选地，在所述第二涂层中，所述硅基材料的质量百分含量为10％～40％。
此外，由于在本申请的负极片中，第一涂层与第二涂层均同时含有硅基材料和碳材料，这样第一涂层与第二涂层可具有良好的界面相容性，从而缓解充电过程中两个涂层承受膨胀应力不均的问题。然而，若第一涂层和第二涂层中硅基材料的质量百分含量相差过小，则本质上其与常规单层设置的负极片无明显差别，从而无法体现出负极膜片多层结构设计的优势；若第一涂层和第二涂层中硅基材料的质量百分含量相差过大，则会导致第一涂层和第二涂层之间的膨胀应力相差过大，在二次电池的充放电过程中会出现第一涂层与第二涂层分离而脱模的情况。
优选地，所述第二涂层中硅基材料的质量百分含量与所述第一涂层中硅基材料的质量百分含量的差值为5％～35％。进一步优选地，所述第二涂层中硅基材料的质量百分含量与所述第一涂层中硅基材料的质量百分含量的差值为10％～30％。
此外，第一涂层和第二涂层中碳材料的质量百分含量的差值也会影响到二次电池的性能。若第一涂层和第二涂层中碳材料的质量百分含量的差值过小，则本质上其与常规单层设置的负极片相比无明显差别，从而无法体现出负极膜片多层结构设计的优势；若第一涂层和第二涂层中碳基材料的质量百分含量相差过大，则会导致第一涂层和第二涂层之间的膨胀应力相差过大，在二次电池的充放电过程中会出现第一涂层与第二涂层分离而脱模的情况。
优选地，所述第一涂层中碳材料的质量百分含量与所述第二涂层中碳材料的质量百分含量的差值为10％～40％。进一步优选地，所述第一涂层中碳材料的质量百分含量与所述第二涂层中碳材料的质量百分含量的差值为10％～20％。
在本申请第一方面所述的负极片中，优选地，所述第一涂层的厚度为20μm～80μm。进一步优选地，所述第一涂层的厚度为20μm～50μm。
在本申请第一方面所述的负极片中，优选地，所述第二涂层的厚度为40μm～140μm。进一步优选地，所述第二涂层的厚度为60μm～100μm。
在本申请第一方面所述的负极片中，优选地，所述第一涂层的厚度与所述第二涂层的厚度的比值为0.2～5。进一步优选地，所述第一涂层的厚度与所述第二涂层的厚度的比值为0.2～2。更进一步优选地，所述第一涂层的厚度与所述第二涂层的厚度的比值为0.5～1。
在本申请第一方面所述的负极片中，所述负极膜片还包括设置在第一涂层和第二涂层之间的互溶扩散层，所述互溶扩散层通过第一涂层和第二涂层互溶扩散形成。互溶扩散层的存在能够进一步改善第一涂层与第二涂层之间的界面相容性，提高第一涂层与第二涂层之间的结合力，避免第二涂层从第一涂层上脱落，从而可以进一步改善二次电池的安全性能。
优选地，所述互溶扩散层的厚度为1μm～20μm。进一步优选地，所述互溶扩散层的厚度为3μm～10μm。
在本申请第一方面所述的负极片中，所述硅基材料可选自无定形硅、晶体硅、硅碳复合物、硅氧化合物、硅合金中的一种几种，所述碳材料可选自人造石墨、天然石墨、中间相碳微球中的一种或几种。
在本申请第一方面所述的负极片中，优选地，在所述第一涂层中，所述硅基材料与所述碳材料的质量百分含量之和为89.5％～99％。
在本申请第一方面所述的负极片中，优选地，在所述第二涂层中，所述硅基材料与所述碳材料的质量百分含量之和为87％～98％。
在本申请第一方面所述的负极片中，所述第一涂层和所述第二涂层均还可包括粘结剂和导电剂，其中，所述粘结剂和导电剂的种类及含量没有具体的限制，可根据实际需求进行选择。需要说明的是，第一涂层中的粘结剂与第二涂层中的粘结剂可以相同，也可以不同。优选地，所述第一涂层中的粘 结剂和所述第二涂层中的粘结剂相同，以便于第一涂层和第二涂层更好地互溶扩散形成互溶扩散层。
优选地，在所述第一涂层中，所述粘结剂的质量百分含量为0.5％～8％。
优选地，在所述第一涂层中，所述导电剂的质量百分含量为0.5％～2.5％。
优选地，在所述第二涂层中，所述粘结剂的质量百分含量为1％～10％。
优选地，在所述第二涂层中，所述导电剂的质量百分含量为1％～3％。
优选地，所述粘结剂可选自聚丙烯酸、聚丙烯酸钠、海藻酸钠、聚丙烯腈、聚乙二醇、羧甲基壳聚糖中的一种或几种。
优选地，所述导电剂可选自乙炔黑、科琴黑、导电碳黑、碳纳米管中的一种或几种。
在本申请第一方面所述的负极片中，所述负极片的制备方法可包括步骤：
(1)第一负极浆料的制备：将硅基材料、碳材料、粘结剂与导电剂按一定比例分散在去离子水中，搅拌0.5h～8h；
(2)第二负极浆料的制备：将硅基材料、碳材料、粘结剂与导电剂按一定比例分散在去离子水中，搅拌0.5h～8h；
(3)负极片的制备：将第二负极浆料涂覆于负极集流体上形成第二涂层，然后将第一负极浆料涂覆于第二涂层上形成第一涂层，之后经冷压、分切，得到负极片。
其次说明根据本申请第二方面的二次电池。
根据本申请第二方面的二次电池包括正极片、负极片、电解液以及隔离膜，其中，所述负极片为根据本申请第一方面所述的负极片。
在本申请第二方面的二次电池中，所述隔离膜的种类并不受到具体的限制，可以是现有二次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。
在本申请第二方面的二次电池中，所述电解液的具体种类及组成均不受到具体的限制，可根据实际需求进行选择。
需要说明的是，根据本申请第二方面的二次电池可为锂离子电池、钠离子电池以及任何其它使用本申请第一方面所述负极片的二次电池。优选地，根据本申请第二方面的二次电池为锂离子电池。
当二次电池为锂离子电池时，正极片中的正极活性材料可选自锂过渡金属复合氧化物中的一种或几种，但本申请并不限于此。优选地，正极活性材料可选自锂钴氧化物、锂锰氧化物、锂镍钴锰氧化物、锂镍锰氧化物、锂镍钴铝氧化物、磷酸铁锂中的一种或几种。
在一些实施例中，二次电池可以包括外包装，用于封装正极极片、负极极片和电解质。作为一个示例，正极极片、负极极片和隔离膜可经叠片或卷绕形成叠片结构电极组件或卷绕结构电极组件，电极组件封装在外包装内；电解质可采用电解液，电解液浸润于电极组件中。二次电池中电极组件的数量可以为一个或几个，可以根据需求来调节。
在一些实施例中，二次电池的外包装可以是软包，例如袋式软包。软包的材质可以是塑料，如可包括聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。电化学装置的外包装也可以是硬壳，例如铝壳等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的电化学装置5。
在一些实施例中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图2是作为一个示例的电池模块4。参照图2，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的壳体，多个二次电池5容纳于该容纳空间。
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3和图4是作为一个示例的电池包1。参照图3和图4，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
最后说明根据本申请第三方面的装置，其包括本申请第二方面所述的二次电池。所述二次电池为所述装置提供电源。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。
所述装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图5是作为一个示例的装置。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化学装置的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
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1-12和对比例1-7的锂离子电池均按照下述方法进行制备。
(1)正极片的制备
将正极活性材料LiNi 0.8Co 0.1Mn 0.1O 2、导电剂乙炔黑、粘结剂PVDF按质量比96:2:2进行混合，加入溶剂NMP，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料；将正极浆料均匀涂覆在正极集流体铝箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切得到正极片。
(2)负极片的制备
将表1所示的第一负极活性材料、粘结剂、导电剂按比例进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得第一负极浆料；将表2所示的第二负极活性材料、粘结剂、导电按比例进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得第二负极浆料；采用单层挤压方式先后将第二负极浆料和第一负极浆料均匀涂覆在负极集流体铜箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切得到负极片。
(3)电解液的制备
将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照按体积比1:1:1进行混合得到有机溶剂，接着将充分干燥的锂盐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
选用聚乙烯膜作为隔离膜。
(5)锂离子电池的制备
将上述正极片、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，然后卷绕得到电极组件；将电极组件置于外包装壳中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，获得锂离子电池。
表1 实施例1-12和对比例1-7的第一涂层参数
Figure PCTCN2020077138-appb-000001
Figure PCTCN2020077138-appb-000002
表2 实施例1-12和对比例1-7的第二涂层参数
Figure PCTCN2020077138-appb-000003
接下来说明锂离子电池的性能测试。
(1)锂离子电池的比能量测试
室温下将锂离子电池在1/3C倍率下充电至上限电压，然后再以1/3C倍率放电至下限电压，得到锂离子电池放电过程中的能量。
锂离子电池的比能量(Wh/Kg)＝锂离子电池放电过程中的能量/锂离子电池的质量。
(2)锂离子电池的首次充放电效率测试
室温下将锂离子电池在0.05C小倍率化成至3.75V，然后在1/3C倍率下充电至上限电压，然后再以1/3C倍率放电至下限电压，得到锂离子电池的首次充电容量和首次放电容量。
锂离子电池的首次充放电效率(％)＝锂离子电池的首次放电容量/锂离子电池的首次充电容量×100％。
(3)锂离子电池的循环性能测试
室温下将锂离子电池在1C倍率下进行充放电循环测试，首先以1C倍率放电至下限电压，静置5min后再以1C倍率充电至上限电压，静置5min，重复以上充放电步骤直至锂离子电池的放电容量衰减至首次放电容量的80％，记录此时锂离子电池的循环圈数。
表3 实施例1-12和对比例1-7的性能测试结果
Figure PCTCN2020077138-appb-000004
Figure PCTCN2020077138-appb-000005
从表3的测试结果分析可知，对比例1-3的负极膜片均为单层结构设置。其中对比例1的负极膜片仅包含硅基材料不包含碳材料，活性锂离子与Si接触反应的活性比表面积较大，负极片发热严重，虽然锂离子电池具有较高的比能量，但是锂离子电池的首次充放电效率较差，同时锂离子电池的循环性能较差；对比例2的负极膜片仅包含碳材料不包含硅基材料，虽然锂离子电池的首次充放电效率较高，同时循环性能较好，但是难以得到高比能量的锂离子电池，进而难以满足实际的使用需求；对比例3的负极膜片既包括碳材料又包括硅基材料，尽管负极片的发热情况与对比例1相比降低，但是其首次充放电效率仍旧较低，难以满足实际的使用需求。
对比例4-7的负极膜片尽管也设置成了多层结构，但是第一涂层或第二涂层不能满足同时含有硅基材料和碳材料，导致第一涂层与第二涂层的界面相容性变差；再者当第一涂层与第二涂层中的硅基材料和碳材料含量相差过大时，充电过程中第一涂层和第二涂层承受的膨胀应力相差过大，第一涂层与第二涂层的界面相容性进一步变差，容易使第一涂层脱落，锂离子电池无法同时兼顾高比能量、高首次充放电效率以及良好的循环性能，从而影响了锂离子电池的使用。
实施例1-12的负极膜片具有多层结构，其包括位于最外层的第一涂层和位于第一涂层与负极集流体之间的第二涂层，同时第一涂层和第二涂层中的硅基材料和碳材料的含量适中，此时锂离子电池具有高比能量和高首次充放电效率，同时锂离子电池还可以兼顾有良好的循环性能。
进一步分析实施例1-9的测试结果可以发现，负极膜片中硅基材料的整 体含量越高，锂离子电池的比能量就越高，但相应的锂离子电池首次充放电效率和循环性能会略微受到影响。同时第一涂层和第二涂层中硅基材料的质量百分含量相差越大，对锂离子电池循环性能的影响就越大，但只要将第一涂层和第二涂层中的硅基材料的质量百分含量控制在适当范围内，锂离子电池就可以具有高比能量和高首次充放电效率，同时还可兼顾有良好的循环性能。
进一步分析实施例2-5的测试结果可以发现，随着第一涂层中硅基材料含量的增加，锂离子电池的比能量和循环性能可以逐步得到改善，但锂离子电池的首次充放电效率会略微降低。
进一步分析实施例6-9的测试结果可以发现，随着第二涂层中硅基材料含量的增加，锂离子电池的比能量可以逐步得到改善，但锂离子电池的首次充放电效率和循环性能会略微降低。
进一步分析实施例10-12的测试结果可以发现，第一涂层和第二涂层采用了与实施例1-9不同的粘结剂，锂离子电池仍旧可以具有高比能量和高首次充放电效率，同时还可兼顾有良好的循环性能。

Claims (11)

  1. 一种负极片，包括负极集流体以及设置于所述负极集流体上的负极膜片；
    其中，
    所述负极膜片包括：
    第一涂层，位于所述负极膜片的最外层且包括第一负极活性材料，所述第一负极活性材料包括硅基材料和碳材料；以及
    第二涂层，设置于所述第一涂层和所述负极集流体之间且包括第二负极活性材料，所述第二负极活性材料包括硅基材料和碳材料；
    在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～10％；和/或
    在所述第二涂层中，所述硅基材料的质量百分含量为5％～50％。
  2. 根据权利要求1所述的负极片，其中，
    在所述第一涂层中，所述硅基材料的质量百分含量为0.5％～5％；和/或
    在所述第二涂层中，所述硅基材料的质量百分含量为10％～40％。
  3. 根据权利要求1或2所述的负极片，其中，所述第二涂层中硅基材料的质量百分含量与所述第一涂层中硅基材料的质量百分含量的差值为5％～35％，优选地，所述第二涂层中硅基材料的质量百分含量与所述第一涂层中硅基材料的质量百分含量的差值为10％～30％。
  4. 根据权利要求1至3任一项所述的负极片，其中，所述第一涂层中碳材料的质量百分含量与所述第二涂层中碳材料的质量百分含量的差值为10％～40％，优选地，所述第一涂层中碳材料的质量百分含量与所述第二涂层中碳材料的质量百分含量的差值为10％～20％。
  5. 根据权利要求1至4任一项所述的负极片，其中，
    在所述第一涂层中，所述硅基材料与所述碳材料的质量百分含量之和为89.5％～99％；和/或
    在所述第二涂层中，所述硅基材料与所述碳材料的质量百分含量之和为87％～98％。
  6. 根据权利要求1至5任一项所述的负极片，其中，
    所述第一涂层的厚度为20μm～80μm，优选为20μm～50μm；和/或
    所述第二涂层的厚度为40μm～140μm，优选为60μm～100μm。
  7. 根据权利要求6所述的负极片，其中，所述第一涂层的厚度与所述第二涂层的厚度的比值为0.2～5，优选为0.2～2，进一步优选为0.5～1。
  8. 根据权利要求1至7中任一项所述的负极片，其中，所述负极膜片还包括设置在第一涂层和第二涂层之间的互溶扩散层，所述互溶扩散层通过第一涂层和第二涂层互溶扩散形成。
  9. 根据权利要求8所述的负极片，其中，所述互溶扩散层的厚度为1μm～20μm，优选为3μm～10μm。
  10. 一种二次电池，其中，包括根据权利要求1至9中任一项所述的负极片。
  11. 一种装置，其中，包括权利要求10所述的二次电池。
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CN114373889A (zh) * 2020-10-15 2022-04-19 Sk新技术株式会社 二次电池用负极及包括其的二次电池
US20220123289A1 (en) * 2020-10-15 2022-04-21 Sk Innovation Co., Ltd. Anode for Secondary Battery, Secondary Battery Including the Same
US20220310991A1 (en) * 2021-03-25 2022-09-29 Sk Innovation Co., Ltd. Anode for Secondary Battery and Lithium Secondary Battery Including the Same
EP4195317A4 (en) * 2021-10-15 2024-03-20 Contemporary Amperex Technology Co., Limited NEGATIVE ELECTRODE PLATE, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND ENERGY CONSUMPTION DEVICE
EP4261913A1 (en) 2022-04-14 2023-10-18 Cellforce Group GmbH Multilayer electrode, a method for manufacturing an electrode and electrochemical storage device
WO2023198921A1 (en) 2022-04-14 2023-10-19 Cellforce Group Gmbh Multilayer electrode, a method for manufacturing an electrode and electrochemical storage device

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EP3916860A4 (en) 2022-04-06
PT3916860T (pt) 2022-11-11
EP3916860A1 (en) 2021-12-01
ES2930297T3 (es) 2022-12-09
CN111640913B (zh) 2021-08-06
EP3916860B1 (en) 2022-09-28
CN111640913A (zh) 2020-09-08
US20210391572A1 (en) 2021-12-16

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