CN114068870B - Positive plate and lithium ion battery comprising same - Google Patents

Positive plate and lithium ion battery comprising same Download PDF

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CN114068870B
CN114068870B CN202111521912.XA CN202111521912A CN114068870B CN 114068870 B CN114068870 B CN 114068870B CN 202111521912 A CN202111521912 A CN 202111521912A CN 114068870 B CN114068870 B CN 114068870B
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coating
binder
positive electrode
positive
lithium
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CN114068870A (en
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张健
彭冲
李俊义
徐延铭
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The invention provides a positive plate and a lithium ion battery comprising the positive plate, wherein the positive plate comprises a positive current collector and a positive coating, and the positive coating comprises a first coating and a second coating; the first coating is coated on the surface of the positive current collector, and the second coating is coated on the surface of the first coating; the first coating layer comprises an inorganic filler, a first conductive agent and a first binder; the second coating comprises a positive electrode active material, a second conductive agent and a second binder; when X is 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) (ii) a The lithium ion battery has good safety performance, and the probability of battery fire and failure is greatly reduced when mechanical abuse (acupuncture and heavy impact) occurs. Meanwhile, the cycle performance of the lithium ion battery is not affected, and the effect of the cycle performance of the lithium ion battery is equivalent to that of the cycle performance of the conventional lithium ion battery, namely the safety performance of the lithium ion battery is obviously improved on the premise of keeping the cycle performance of the lithium ion battery.

Description

Positive plate and lithium ion battery comprising same
The present application claims the priority of the prior application entitled "a positive plate and a lithium ion battery comprising the positive plate" filed from the intellectual property office of china with patent application number 202011468005.9 on 12, month and 14 of 2020, the entire content of which is incorporated herein by reference.
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive plate and a lithium ion battery comprising the same.
Background
The lithium ion battery has the advantages of high platform voltage, high energy density, no memory effect, long service life and the like, and is widely applied to the fields of smart phones, notebook computers, bluetooth, wearable equipment and the like. However, in some extreme cases, for example, when the lithium ion battery is subjected to mechanical damage (needle prick, heavy impact, etc.), an internal short circuit may occur, and the lithium ion battery with the internal short circuit may emit a large amount of heat in a short time, resulting in a fire and a failure of the battery, which has a great potential safety hazard.
Research shows that when the lithium ion battery is subjected to internal short circuit, various short circuit modes exist, wherein the short circuit between the positive current collector foil and the negative electrode plate is the most dangerous mode.
Disclosure of Invention
The invention provides a positive plate and a lithium ion battery comprising the same, wherein the use of the positive plate can solve the problems of fire failure and the like of the lithium ion battery under the condition of mechanical abuse, the safety performance of the lithium ion battery is improved, meanwhile, the cycle performance of the lithium ion battery is not influenced, and the cycle performance of the lithium ion battery is equivalent to the cycle performance effect of the conventional lithium ion battery, namely, the safety performance of the lithium ion battery is obviously improved on the premise of keeping the cycle performance of the lithium ion battery.
The invention is realized by the following technical scheme:
a positive plate comprises a positive current collector and a positive coating, wherein the positive coating comprises a first coating and a second coating, the first coating is coated on the surface of the positive current collector, and the second coating is coated on the surface of the first coating; the first coating layer includes an inorganic filler, a first conductive agent, and a first binder, and the second coating layer includes a positive electrode active material, a second conductive agent, and a second binder;
wherein, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )；
Wherein, X 1 Is the content of the first binder, Y 1 Is the content of inorganic filler, Z 1 Is the content of the first conductive agent; s. the Y1 The specific surface area of the inorganic filler; s Z1 Is the specific surface area of the first conductive agent; x 2 Is the content of the second binder, Y 2 Is the content of the positive electrode active material, Z 2 Is the content of the second conductive agent; s. the Y2 Is the specific surface area of the positive electrode active material; s Z2 Is the specific surface area of the second conductive agent.
According to the invention, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>1.5X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )。
Preferably, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>4X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )。
According to the invention, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 ) 0.004-0.15 g/m 2 Preferably 0.01 to 0.1g/m 2 . Such as 0.004g/m 2 、0.005g/m 2 、0.006g/m 2 、0.008g/m 2 、0.01g/m 2 、0.02g/m 2 、0.03g/m 2 、0.04g/m 2 、0.05g/m 2 、0.06g/m 2 、0.07g/m 2 、0.08g/m 2 、0.09g/m 2 、0.1g/m 2 、0.11g/m 2 、0.12g/m 2 、0.13g/m 2 、0.14g/m 2 Or 0.15g/m 2 。
According to the invention, X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) 0.002-0.003 g/m 2 。
The research finds that X is satisfied 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) The first coating layer of (a) may be preferably bonded to the positive electrode current collector, wherein X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 ) And X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) Each represents the amount of binder per unit mass of the surface of the substance to be bonded (such as the inorganic filler and the first conductive agent, or such as the positive electrode active material and the second conductive agent); and the binding properties are related to the amount of binder and the specific surface area of the bound particles. The larger the amount of the binder, the smaller the specific surface area, the more the binder per specific surface area, and the better the binding effect. The good cohesiveness can make the first coating and the positive current collector not easy to separate. The adhesive force between the first coating and the positive current collector can realize that the surface of the positive current collector can be well protected by the first coating and is not easy to expose under the condition of mechanical abuse (needling and heavy impact), so that the contact probability of the positive current collector and the negative plate is reduced, the short circuit probability of the positive current collector and the negative plate is reduced, and the safety of the battery is improved.
According to the invention, X 1 +Y 1 +Z 1 ＝1；X 2 +Y 2 +Z 2 =1; wherein X 1 、Y 1 、Z 1 、X 2 、Y 2 、Z 2 Is as defined above.
The invention also provides a lithium ion battery which comprises the positive plate.
The invention has the beneficial effects that:
the invention provides a positive plate and a lithium ion battery comprising the positive plate, wherein the positive plate comprises a positive current collector and a positive coating, and the positive coating comprises a first coating and a second coating; the first coating is coated on the surface of the positive current collector, and the second coating is coated on the surface of the first coating; the first coating comprisesThe conductive paste comprises organic filler, a first conductive agent and a first binder; the second coating layer includes a positive electrode active material, a second conductive agent, and a second binder; when X is 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) (ii) a Wherein, X 1 Is the content of the first binder, Y 1 Is the content of the inorganic filler, Z 1 Is the content of the first conductive agent; s. the Y1 The specific surface area of the inorganic filler; s Z1 Is the specific surface area of the first conductive agent; x 2 Content of the second binder, Y 2 Is the content of the positive electrode active material, Z 2 Is the content of the second conductive agent; s. the Y2 Is the specific surface area of the positive electrode active material; s Z2 Is the specific surface area of the second conductive agent. The lithium ion battery has good safety performance, and the probability of battery fire and failure is greatly reduced when mechanical abuse (acupuncture and heavy impact) occurs. Meanwhile, the cycle performance of the lithium ion battery is not affected, and the effect of the cycle performance of the lithium ion battery is equivalent to that of the cycle performance of the conventional lithium ion battery, namely the safety performance of the lithium ion battery is obviously improved on the premise of keeping the cycle performance of the lithium ion battery.
Drawings
Figure 1 example 1 SEM remained on the surface of the pole piece after the peel test.
FIG. 2 SEM of the front sheet of example 1 peel test.
Detailed Description
As described above, the present invention provides a positive electrode sheet, including a positive electrode current collector and a positive electrode coating, where the positive electrode coating includes a first coating and a second coating, the first coating is coated on the surface of the positive electrode current collector, and the second coating is coated on the surface of the first coating; the first coating layer comprises an inorganic filler, a first conductive agent and a first binder, and the second coating layer comprises a positive electrode active material, a second conductive agent and a second binder;
wherein, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )；
Wherein X 1 Is the content of the first binder, Y 1 Is the content of the inorganic filler, Z 1 Is the content of the first conductive agent; s. the Y1 The specific surface area of the inorganic filler; s Z1 Is the specific surface area of the first conductive agent; x 2 Content of the second binder, Y 2 Is the content of the positive electrode active material, Z 2 Is the content of the second conductive agent; s Y2 Is the specific surface area of the positive electrode active material; s Z2 Is the specific surface area of the second conductive agent.
According to the invention, the median particle diameter D of the inorganic filler 50 Less than the median particle diameter D of the positive electrode active material 50 。
According to the invention, the content of the first binder in the first coating layer is greater than the content of the second binder in the second coating layer.
According to the present invention, the positive electrode current collector is bonded to a part of the first binder, and a part of the positive electrode active material is bonded to another part of the first binder.
In the present invention, the median particle diameter D of the inorganic filler 50 Less than the median particle diameter D of the positive electrode active material 50 And the positive electrode active material in the second coating layer is embedded into the first coating layer (see the SEM image shown in fig. 2 of the present application in particular), so that a part of the first binder in the first coating layer is in contact with the positive electrode current collector, and another part of the first binder is in contact with the positive electrode active material, that is, a structure is formed in which the positive electrode current collector is bonded to a part of the first binder, and a part of the positive electrode active material is bonded to another part of the first binder.
According to the invention, only the second coating on the surface of the positive current collector and/or partial particles of the first coating can be stripped from the surface of the positive current collector after the stripping test.
For example, only the second coating part particles on the surface of the pole piece subjected to the stripping test are stripped from the positive pole piece, only the positive active material particles of the second coating can be detected on the surface of the stripped pole piece, and the particles of the first coating are not detected; alternatively, the first and second liquid crystal display panels may be,
part of particles of the pole piece surface coating after the stripping test are stripped from the positive pole piece, and inorganic filler particles of the first coating and positive active material particles of the second coating can be detected on the surface of the stripped pole piece, but the positive current collector is not leaked.
More specifically, when the inorganic filler is lithium iron phosphate and the positive electrode active material is lithium cobaltate, the Co and O elements are detected in EDS on the surface of the positive electrode coating remaining on the positive electrode current collector after the positive electrode coating of the positive electrode sheet is peeled off. This result indicates at least that the adhesion between the first coating layer and the positive electrode current collector is greater than the adhesion between the first coating layer and the second coating layer, and/or the adhesion between the first coating layer and the positive electrode current collector is greater than the adhesion between the positive electrode active material particles of the second coating layer.
According to the invention, the median particle diameter D of the inorganic filler 50 0.05-8 μm; the specific surface area is 0.6 to 12m 2 (ii) in terms of/g. The use of small particle size inorganic fillers can make the first coating thinner and denser.
According to the invention, the median particle diameter D of the positive electrode active material 50 Is 10-20 μm; the specific surface area is 0.1 to 0.3m 2 (ii) in terms of/g. Selection of this particle size range provides a higher compacted density, increasing the capacity density.
According to the present invention, the inorganic filler forming the first coating layer and the positive electrode active material of the second coating layer are the same or different, the first conductive agent and the second conductive agent and the content thereof are the same or different, and the first binder and the second binder and the content thereof are the same or different.
According to the invention, the first coating comprises the following components in percentage by mass: 40-93wt% of inorganic filler, 2-15wt% of first conductive agent and 5-58wt% of first binder.
Preferably, the first coating comprises the following components in percentage by mass: 60-91wt% of inorganic filler, 3-10wt% of first conductive agent and 8-30wt% of first binder. When the first binder is in the range, the first binder can have a good binding effect with the positive current collector, and the energy density is reduced due to the fact that the content of the first binder is too highThe content of the first binder is selected to deteriorate the cell performance, and the median particle diameter D 50 The inorganic filler with the diameter of 0.05-8 μm is combined to form a strong and compact base coat.
Illustratively, the inorganic filler comprises 40wt%, 45wt%, 48wt%, 50wt%, 55wt%, 58wt%, 60wt%, 62wt%, 65wt%, 68wt%, 70wt%, 72wt%, 75wt%, 78wt%, 80wt%, 82wt%, 85wt%, 88wt%, 90wt%, 92wt%, 93wt% of the components of the first coating layer by mass;
illustratively, the first conductive agent accounts for 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt% of the components in the first coating layer by mass;
illustratively, the first binder is present in the first coating in an amount of 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, 30wt%, 33wt%, 35wt%, 38wt%, 40wt%, 45wt%, 48wt%, 50wt%, 55wt%, 58wt% based on the weight of each component.
According to the invention, the second coating comprises the following components in percentage by mass: 93-99wt% of positive electrode active material, 0.5-5wt% of second conductive agent and 0.5-2wt% of second binder. The second binder is selected within this range of content to provide better bonding while maintaining a higher energy density.
Preferably, the second coating comprises the following components in percentage by mass: 95-98wt% of positive electrode active material, 1-3wt% of second conductive agent and 1-2wt% of second binder.
Illustratively, the mass percentage of the positive electrode active substance in each component of the second coating is 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%;
illustratively, the second conductive agent accounts for 0.5wt%, 1wt%, 1.5wt%, 1.8wt%, 2wt%, 2.2wt%, 2.5wt%, 2.8wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt% of each component in the second coating layer;
illustratively, the second binder accounts for 0.5wt%, 1wt%, 1.5wt%, 1.8wt%, 2wt% of each component in the second coating layer.
According to the invention, the first conductive agent and the second conductive agent are the same or different and are independently selected from at least one of conductive carbon black, carbon nanotubes and graphene.
According to the invention, the first binder and the second binder are the same or different and are independently selected from at least one of polyvinylidene fluoride and modified polyvinylidene fluoride.
Wherein, the polyvinylidene fluoride and the modified polyvinylidene fluoride are both products sold in the market.
According to the invention, the crystallinity of the first binder is <40%, since a low crystallinity is advantageous for a better bonding effect.
According to the present invention, the crystallinity of the second binder is <40%, because a low crystallinity is advantageous for having a good bonding effect.
According to the invention, the modified polyvinylidene fluoride is acrylate modified polyvinylidene fluoride. The acrylate group contains carboxyl, and can form a chemical bond with a positive current collector (such as aluminum foil) to realize strong bonding with the positive current collector.
According to the invention, the molecular weight of the polyvinylidene fluoride or modified polyvinylidene fluoride is 100 to 150 ten thousand, for example 110 ten thousand, 130 ten thousand. The selection of the binder with larger molecular weight can enhance the binding performance, reduce the content of the binder and enhance the energy density.
According to the invention, the inorganic filler is selected from lithium-containing transition metal oxides, in particular from one or more of Lithium Cobaltate (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium Manganese Phosphate (LMP), lithium Vanadium Phosphate (LVP), lithium Manganate (LMO), lithium-rich manganese base;
or, the inorganic filler is selected from ceramic materials, and is specifically selected from one or more of alumina, boehmite, magnesium oxide and magnesium hydroxide;
or, the inorganic filler is selected from a mixture of at least one of lithium-containing transition metal oxides and at least one of ceramic materials.
In the present invention, the inorganic filler functions as a skeleton support.
According to the present invention, the positive active material is selected from one or more of Lithium Cobaltate (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium Manganese Phosphate (LMP), lithium Vanadium Phosphate (LVP), lithium Manganate (LMO), and lithium-rich manganese base.
According to the invention, the positive current collector is selected from aluminium foils.
According to the invention, the thickness of the positive electrode current collector is 8-15 μm.
According to the invention, the thickness of the first coating (thickness after rolling) is 2-10 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm; the thickness of the second coating layer (thickness after rolling) is 30-80 μm, such as 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm or 80 μm.
The invention also provides a preparation method of the positive plate, which comprises the following steps:
1) Respectively preparing slurry for forming a first coating and slurry for forming a second coating;
2) And coating the slurry for forming the first coating and the slurry for forming the second coating on the two side surfaces of the positive current collector to prepare the positive plate.
According to the invention, in step 2), the coating is a double coating, a gravure coating, an extrusion coating, a transfer coating.
Exemplarily, the step 2) specifically includes the following steps:
and coating the slurry for forming the first coating on the surface of the positive current collector to form the first coating, and coating the slurry for forming the second coating on the surface of the first coating to form the second coating, so as to obtain the positive plate.
The invention also provides a lithium ion battery which comprises the positive plate.
According to the present invention, the lithium ion battery further comprises a negative electrode sheet.
According to the invention, the negative plate comprises a negative active material, and the negative active material is selected from one or more of artificial graphite, natural graphite, mesocarbon microbeads, lithium titanate, silicon carbon negative electrodes and silicon oxygen negative electrodes.
The invention also provides a preparation method of the lithium ion battery, which comprises the following steps:
a) Preparing a positive plate and a negative plate;
b) And rolling, slitting, flaking, winding (or laminating), packaging, injecting, forming, grading, OCV and other procedures are carried out on the positive plate and the negative plate to prepare the lithium ion battery.
The present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
The modified PVDF used in the examples described below was an acrylate modified PVDF, commercially available under the trade designation Solef 5130. The molecular weight of the acrylate modified PVDF is 110 ten thousand, and the crystallinity is 30-32%.
PVDF used in the examples described below is commercially available as PVDF manufactured by Arkema corporation under the designation HSV-900. The molecular weight of the PVDF is 100 ten thousand, and the crystallinity is 25%.
In the description of the present invention, it should be noted that the terms "first", "second", etc. are used for descriptive purposes only and do not indicate or imply relative importance.
The adhesion test used in the following examples was as follows:
dissecting after the lithium ion battery is completely discharged (0.5C is discharged to 3.0V), taking out the positive plate, placing the positive plate at the temperature of 25 +/-3 ℃, standing for 2h in the environment with the dew point of minus 30 ℃, cutting the positive plate into positive plate small pieces with the length of 240mm and the width of 30mm, cutting the adhesive tapes into adhesive tape small pieces according to the specification of the length of 200mm and the width of 24mm by using NITTO No.5000NS adhesive tapes, adhering one surfaces of the adhesive tape small pieces to a steel plate (260mm 50mm), adhering the positive plate small pieces to the other surfaces of the adhesive tape small pieces to ensure that the positive plate small pieces completely cover the adhesive tape small pieces, rolling for 3 times in a reciprocating manner by using a handheld roller (the diameter of 95mm, the width of 45mm and the weight of 2 kg), adhering the positive plate small pieces and the adhesive tape small pieces together, then testing (180-degree stripping) by using a tensile machine (a KJ-1065 series of a tensile machine model, and automatically recording the tensile force which changes along with the stripping displacement, and making a curve, wherein the horizontal coordinate is the tensile force is the stripping force which is greater than 5 mm.
The test method for the safety test used in the following examples is as follows:
(1) And (3) needle punching test:
the cell was fully charged and the center of the cell was punctured perpendicular to the plane of the cell at 130mm/s using a 3mm steel needle.
(2) And (3) testing the impact of the weight:
the cell was fully charged, the cell was placed in a plane, a steel column 15.8 + -0.2 mm in diameter was placed in the center of the cell with the longitudinal axis of the column parallel to the plane, allowing a weight of 9.1 + -0.1 kg to fall freely from a height of 610 + -25 mm onto the column above the center of the cell.
Example 1
The first step is as follows: preparing first coating slurry, mixing 80wt% of lithium iron phosphate (LFP), 15wt% of modified PVDF and 5wt% of carbon black, adding NMP, and stirring to prepare the slurry.
The second step is that: preparing a second coating slurry by mixing 97wt% lithium cobaltate, 1wt% conductive carbon black, 0.8wt% carbon nanotubes, 1.2wt% PVDF, adding NMP, and stirring to prepare a slurry.
The third step: preparing a negative electrode slurry, mixing 96wt% artificial graphite, 1wt% conductive carbon black, 1.5wt% sbr and 1.5wt% cmc, adding deionized water, preparing a slurry by stirring.
The fourth step: and (3) preparing a positive pole piece, namely coating the first coating slurry obtained in the first step on the surface of a positive current collector by using an extrusion coating process to form a first coating with the thickness of 5 microns, and coating the second coating slurry obtained in the second step on the surface of the first coating to form a second coating with the thickness of 40 microns to obtain the binding power positive pole piece.
The fifth step: and (4) preparing a negative pole piece, namely coating the negative pole slurry obtained in the step three on a negative pole current collector to obtain the negative pole piece.
And a sixth step: and rolling the positive and negative pole pieces, slitting, making the pieces, winding (or laminating), packaging, injecting liquid, forming, grading the capacity, OCV and the like to prepare the lithium ion battery.
The prepared lithium ion battery is subjected to a cohesive force test, and the section of the peeled pole piece is shown in figure 1. The left side is a stripped surface, the right side is a complete surface, only partial particles of the second coating layer are stripped from the stripped surface of the pole piece, and the first coating layer is well preserved (the thickness of the first coating layer is less than 10 mu m), which shows that the bonding effect of the first coating layer is better than that of the second coating layer.
Examples 2 to 9
Other steps are the same as example 1, and only differ in the selection and content of each material in the first step, and/or the selection and content of each material in the second step are specifically shown in table 1.
Comparative example 1
The other steps are the same as example 1, and only differ in the selection and content of each material in the first step, and/or the selection and content of each material in the second step are specifically shown in table 1.
As can be seen from the above examples and comparative examples,
when X is present 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) In the process, the use of the positive plate can solve the problems of fire failure and the like of the lithium ion battery under the condition of mechanical abuse, and improve lithiumThe safety performance of the ion battery is not affected, and the cycle performance of the ion battery is equivalent to that of the existing lithium ion battery, namely the safety performance of the ion battery is remarkably improved on the premise of keeping the cycle performance of the lithium ion battery.
In particular, when X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>4X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) During the process, the safety performance of the lithium ion battery can be further improved by using the positive plate, the binding force between the first coating and the positive current collector is greater than 30N/m, namely, under the condition that the lithium ion battery is subjected to mechanical abuse, the first coating can well protect the positive current collector, and the problems of fire failure and the like caused by contact with a negative electrode are avoided.
TABLE 1 Pole piece peel force magnitude and safety test results for each example and comparative example
Figure BDA0003407819660000111
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. The positive plate comprises a positive current collector and a positive coating, wherein the positive coating comprises a first coating and a second coating, the first coating is coated on the surface of the positive current collector, and the second coating is coated on the surface of the first coating; the first coating layer includes an inorganic filler, a first conductive agent, and a first binder, and the second coating layer includes a positive electrode active material, a second conductive agent, and a second binder;
wherein, X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )；
Wherein, X 1 Is the content of the first binder, Y 1 Is the content of inorganic filler, Z 1 Is the content of the first conductive agent; s Y1 The specific surface area of the inorganic filler; s Z1 Is the specific surface area of the first conductive agent; x 2 Is the content of the second binder, Y 2 Is the content of the positive electrode active material, Z 2 Is the content of the second conductive agent; s. the Y2 Is the specific surface area of the positive electrode active material; s. the Z2 Is the specific surface area of the second conductive agent;
median particle diameter D of the inorganic filler 50 Smaller than the median diameter D of the positive electrode active material 50 ；
X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 ) 0.004 to 0.15g/m 2 ；X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 ) 0.002 to 0.003g/m 2 ；
The first coating comprises the following components in percentage by mass: 40-93wt% of inorganic filler, 2-15wt% of first conductive agent, and 5-58wt% of first binder;
the second coating comprises the following components in percentage by mass: 93-99wt% of positive electrode active material, 0.5-5wt% of second conductive agent and 0.5-2wt% of second binder.
2. The positive electrode sheet according to claim 1,
X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>1.5X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )。
3. the positive electrode sheet according to claim 2,
X 1 /(Y 1 ×S Y1 +Z 1 ×S Z1 )>4X 2 /(Y 2 ×S Y2 +Z 2 ×S Z2 )。
4. the positive electrode sheet according to any one of claims 1 to 3, wherein the content of the first binder in the first coating layer is larger than the content of the second binder in the second coating layer; and/or the presence of a gas in the gas,
the positive electrode current collector is bonded to a part of the first binder, and a part of the positive electrode active material is bonded to another part of the first binder.
5. The positive electrode sheet according to any one of claims 1 to 3, wherein the first binder and the second binder are the same or different and are independently selected from at least one of polyvinylidene fluoride and modified polyvinylidene fluoride; and/or the presence of a gas in the atmosphere,
the crystallinity of the first binder is <40%; and/or the presence of a gas in the atmosphere,
the modified polyvinylidene fluoride is acrylate modified polyvinylidene fluoride; and/or the presence of a gas in the gas,
the molecular weight of the polyvinylidene fluoride or the modified polyvinylidene fluoride is 100-150 ten thousand.
6. The positive electrode sheet according to any one of claims 1 to 3, wherein the inorganic filler is selected from lithium-containing transition metal oxides, in particular from one or more of Lithium Cobaltate (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium Manganese Phosphate (LMP), lithium Vanadium Phosphate (LVP), lithium Manganate (LMO), lithium rich manganese base; or the like, or, alternatively,
the inorganic filler is selected from ceramic materials, and is specifically selected from one or more of alumina, boehmite, magnesium oxide and magnesium hydroxide; or the like, or a combination thereof,
the inorganic filler is selected from a mixture of at least one of lithium-containing transition metal oxides and at least one of ceramic materials; and/or the presence of a gas in the gas,
the positive active material is selected from one or more of Lithium Cobaltate (LCO), a nickel-cobalt-manganese ternary material (NCM), a nickel-cobalt-aluminum ternary material (NCA), a nickel-cobalt-manganese-aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium Manganese Phosphate (LMP), lithium Vanadium Phosphate (LVP) and Lithium Manganate (LMO).
7. A lithium ion battery comprising the positive electrode sheet according to any one of claims 1 to 6.
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CN113224262B (en) * 2021-04-30 2023-01-24 珠海冠宇电池股份有限公司 Positive plate and lithium ion battery
WO2023087301A1 (en) * 2021-11-22 2023-05-25 东莞新能源科技有限公司 Electrochemical apparatus and electronic device containing said electrochemical apparatus
CN114122638A (en) * 2021-11-23 2022-03-01 珠海冠宇电池股份有限公司 Battery with a battery cell
CN114122320B (en) * 2021-11-25 2023-06-27 珠海冠宇电池股份有限公司 Electrode sheet and electrochemical device
CN114361381A (en) * 2021-12-20 2022-04-15 珠海冠宇电池股份有限公司 Lithium ion battery
CN114267816A (en) * 2021-12-21 2022-04-01 珠海冠宇电池股份有限公司 Positive plate and battery thereof
CN114464792A (en) * 2022-02-10 2022-05-10 湖北亿纬动力有限公司 Battery pole piece and preparation method and application thereof
CN115224267A (en) * 2022-07-25 2022-10-21 江苏正力新能电池技术有限公司 Positive plate, secondary battery and power utilization device
WO2024087450A1 (en) * 2022-10-24 2024-05-02 珠海冠宇电池股份有限公司 Stacked battery cell and lithium ion battery

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170009097A (en) * 2015-07-15 2017-01-25 주식회사 엘지화학 Cathode improved conductivity and electrochemical device including the same
CN109411716A (en) * 2018-09-18 2019-03-01 深圳市优特利电源有限公司 Based lithium-ion battery positive plate and preparation method thereof and lithium ion battery
CN111900392A (en) * 2020-06-22 2020-11-06 珠海冠宇电池股份有限公司 Positive plate and lithium ion battery containing same

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4752574B2 (en) * 2006-03-30 2011-08-17 ソニー株式会社 Negative electrode and secondary battery
JP5261961B2 (en) * 2007-04-06 2013-08-14 トヨタ自動車株式会社 Secondary battery positive electrode, secondary battery negative electrode, secondary battery, and vehicle
JP5150966B2 (en) * 2007-05-28 2013-02-27 Ｎｅｃエナジーデバイス株式会社 Non-aqueous electrolyte secondary battery positive electrode and non-aqueous electrolyte secondary battery using the same
KR101313078B1 (en) * 2010-09-30 2013-09-30 주식회사 엘지화학 Cathode for lithium secondary battery and Lithium secondary battery comprising the same
KR102023732B1 (en) * 2015-07-29 2019-09-20 주식회사 엘지화학 Electrode and electrochemical device including the same
KR102062689B1 (en) * 2016-11-23 2020-01-06 주식회사 엘지화학 Positive electrode for secondary battery and lithium secondary battery comprising the same
CN109037592A (en) * 2017-06-09 2018-12-18 宁德时代新能源科技股份有限公司 Lithium ion battery positive plate, preparation method thereof and lithium ion battery
CN109755468B (en) * 2017-11-08 2021-01-12 宁德时代新能源科技股份有限公司 Electrode pole piece, electrochemical device and safety coating
JP7007944B2 (en) * 2018-02-08 2022-01-25 三洋化成工業株式会社 Positive electrode for lithium-ion batteries and lithium-ion batteries
CN109585779A (en) * 2018-10-30 2019-04-05 福建冠城瑞闽新能源科技有限公司 Take into account the lithium ion cell electrode piece and preparation method of energy density and power density
CN109461882B (en) * 2018-11-05 2021-10-01 宁德新能源科技有限公司 Positive electrode plate, electrochemical device and electronic device comprising same
CN111200103B (en) * 2018-11-16 2021-01-08 宁德时代新能源科技股份有限公司 Battery with a battery cell
CN109585780A (en) * 2018-12-24 2019-04-05 珠海光宇电池有限公司 A kind of anode composite pole piece and preparation method thereof and the lithium ion battery containing the pole piece
CN111900343B (en) * 2020-06-18 2022-05-13 珠海冠宇电池股份有限公司 Positive pole piece and preparation method and application thereof
CN111900328A (en) * 2020-06-22 2020-11-06 珠海冠宇电池股份有限公司 Positive plate and lithium ion battery containing same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170009097A (en) * 2015-07-15 2017-01-25 주식회사 엘지화학 Cathode improved conductivity and electrochemical device including the same
CN109411716A (en) * 2018-09-18 2019-03-01 深圳市优特利电源有限公司 Based lithium-ion battery positive plate and preparation method thereof and lithium ion battery
CN111900392A (en) * 2020-06-22 2020-11-06 珠海冠宇电池股份有限公司 Positive plate and lithium ion battery containing same

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