CN114583100A - Positive plate, preparation method thereof and lithium ion battery - Google Patents

Positive plate, preparation method thereof and lithium ion battery Download PDF

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Publication number
CN114583100A
CN114583100A CN202210277758.4A CN202210277758A CN114583100A CN 114583100 A CN114583100 A CN 114583100A CN 202210277758 A CN202210277758 A CN 202210277758A CN 114583100 A CN114583100 A CN 114583100A
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coating
positive
positive electrode
safety
layer
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谭远高
王铭雪
黄旭
陈杰
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Huizhou Liwinon Energy Technology Co Ltd
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Huizhou Liwinon Energy Technology 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive plate, a preparation method thereof and a lithium ion battery, wherein the positive plate comprises the following steps: the surface of one side of the positive current collector is provided with a first coating area and a hollow foil area, the first coating area and the hollow foil area are arranged in parallel, and the surface of the other side of the positive current collector is provided with a second coating area; the safety coating is arranged in the first coating area and the second coating area, and the resistance is 0.13-3 omega; the insulating layer is arranged in the empty foil area; and a positive active layer disposed on an outer surface of the safety coating layer. According to the positive plate, the safety coatings are arranged on the surfaces of the two sides of the positive current collector, so that the adhesive force between the positive current collector and the positive coating is increased, the positive current collector is prevented from contacting with the negative active coating to generate short circuit when the positive current collector is subjected to a needling test, a unilateral test and a foreign matter extrusion test, and the safety coatings have certain internal resistance, so that the internal resistance of a battery cell can be increased, the short-circuit current is reduced, and the thermal impact and external short circuit performance of the battery cell are improved.

Description

Positive plate, preparation method thereof and lithium ion battery
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive plate, a preparation method of the positive plate and a lithium ion battery.
Background
The lithium ion battery has the advantages of high specific energy, strong continuous capability, long cycle life, wide working range, short charging time, large-current discharge and the like, and is widely applied to the power fields of electric vehicles and the like and the consumption fields of mobile phones, watches, flat plates, notebooks and the like.
With the development of lithium ion batteries in the fields of fast charging, high energy density and the like, the safety problem caused by the battery core becomes the focus of attention of people gradually. Lithium ion battery mechanical abuse safety tests such as needling, single-side extrusion, and foreign matter extrusion are one direction of attention by the home.
Four contact short circuits can occur in the lithium ion battery in the testing processes of needling, unilateral extrusion, foreign matter extrusion and the like, namely, a positive active material and a negative active material, a positive active material and a negative current collector, a positive current collector and a negative active material, and a positive current collector and a negative current collector. Among the four short-circuiting methods, the short-circuiting method in which thermal runaway is most likely to occur is a short-circuiting between the "positive electrode current collector and the negative electrode active material".
The existing diaphragm and electrolyte have limited capability of improving the safety of the battery core, are more used for improving the safety of thermal abuse such as thermal shock and the like, and have no obvious effect on improving the safety of mechanical abuse such as acupuncture, unilateral extrusion, foreign matter extrusion and the like.
Disclosure of Invention
One of the objects of the present invention is: the positive plate is provided aiming at the defects of the prior art, and the problem that the pole piece can not pass the mechanical performance test of needling, unilateral extrusion and foreign matter extrusion can be solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a positive electrode sheet, comprising:
the surface of one side of the positive current collector is provided with a first coating area and a hollow foil area, the first coating area and the hollow foil area are arranged in parallel, and the surface of the other side of the positive current collector is provided with a second coating area;
the safety coating is arranged in the first coating area and the second coating area, and the resistance of the safety coating is 0.13-3 omega; the insulating layer is arranged in the empty foil area;
and a positive active layer disposed on an outer surface of the safety coating layer.
According to the positive plate, the safety coatings are arranged on the surfaces of the two sides of the positive current collector, so that the adhesive force and the mechanical strength of the positive current collector and the positive active layer are increased, the plate does not fall off in the mechanical abuse test process, the aluminum foil is prevented from being in direct contact with the negative active material, meanwhile, the safety coatings have certain internal resistance, the current in the short circuit process is reduced, and the resistance of the dry film membrane of the safety coatings is 0.13-3 omega.
Compared with the battery cell improved by electrolyte additives and diaphragms, the battery cell has safer mechanical abuse, shorter time consumption and simpler process, the resistance range of the safety coating diaphragm is 0.13-3 omega by controlling the addition amount of inorganic filler and conductive agent, the short-circuit resistance is increased in the needling process, the short-circuit current is reduced, the heat generated in the short-circuit process is reduced, and the improvement effect on the battery cell in needling, unilateral extrusion and foreign matter extrusion tests is more obvious. Meanwhile, the resistance range of the dry film diaphragm of the safety coating is 0.13-3.0 omega, the internal resistance of the battery cell is increased, and the thermal shock and external short circuit are improved to a certain extent.
Preferably, the safety coating comprises a first positive electrode active substance, an inorganic filler, a first conductive agent and a first adhesive, wherein the weight part ratio of the first positive electrode active substance to the inorganic filler to the first conductive agent to the first adhesive is 28-95.6: 3-50: 0.2-2: 1-20. The weight parts of the first positive electrode active material, the inorganic filler, the first conductive agent and the first adhesive are 47:5:0.5:5, 50:13:1.5:15, 60:13:1.5:15, 70:13:1.5:15, 80:13:1.5:15, 90:13:1.5:15, 95.8:13:3:15 and 90:24:2: 19.
Preferably, the coating surface density of the safety coating is 4-30 mg/1540.25mm2。
Preferably, the security coating comprises a first security coating disposed in a first coating zone and a second security coating disposed in a second coating zone; the length of the first security coating is less than the length of the second security coating.
Preferably, the insulating layer comprises a first insulating material and a binder, the insulating material is one or more of alumina, boehmite, silicon oxide, titanium oxide and polymethyl methacrylate, and the binder is one or more of polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, polytetrafluoroethylene and polyvinyl alcohol.
Preferably, the difference in thickness between the insulating layer and the security coating is less than or equal to 7 μm. The coating of the positive active layer is prevented from being influenced by the overlarge thickness difference between the safety coating and the insulating layer.
Preferably, the positive active layer includes a first active layer disposed on an outer surface of the first safety coating layer and a second active layer disposed on an outer surface of the second safety coating layer, and a length of the first active layer is less than a length of the second active layer.
Preferably, the positive electrode active layer comprises a second positive electrode active material, a second conductive agent and a second adhesive, and the weight part ratio of the second positive electrode active material to the second conductive agent to the second adhesive is 95-98: 1-3: 0.5-2. The weight ratio of the second positive electrode active material to the second conductive agent to the second adhesive is 95:1:0.5, 96:1:0.5, 97:1:0.5, 98:1:0.5, 95:2:0.5, 98:1:0.9, 95:2:1, 98:1:1.5, 95:2:0.5, 98:1:0.5, 97:2:0.5, 98:2:0.8 and 97:1.5: 0.6.
The second purpose of the invention is: aiming at the defects of the prior art, the preparation method of the positive plate is provided, and has the advantages of simple operation, batch production and good controllability.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a positive plate comprises the following steps:
step S1, mixing and stirring the positive active substance, the inorganic filler, the conductive agent and the adhesive to prepare safety coating slurry, coating the safety coating slurry on a first coating area and a second coating area on the surface of the positive current collector, and drying to form a safety coating to obtain a first substrate;
step S2, mixing the insulating material and the adhesive to prepare insulating slurry, coating the insulating slurry on a hollow foil area on the surface of the positive electrode current collector, and drying to form an insulating layer to prepare a second substrate;
and step S3, mixing and stirring the positive active substance, the conductive agent and the adhesive to prepare positive active slurry, coating the positive active slurry on the surface of the safety coating, and drying to form a positive active layer to obtain the positive plate.
The addition amount of the inorganic filler in the safety coating is 3-50 wt%, the conductive agent is one or a mixture of more of conductive carbon black, carbon nano tubes and graphene, the addition amount of the conductive agent is 0.2-2 wt%, and the conductive agent is used for providing certain conductivity for the safety coating and ensuring the safety performance of the battery. The first adhesive and/or the second adhesive are/is one or a mixture of polyvinylidene fluoride, Styrene Butadiene Rubber (SBR), polyacrylic acid, polytetrafluoroethylene and polyvinyl alcohol, the addition amount of the adhesive is 1-20 wt%, and the adhesive mainly functions to provide a strong adhesive for the safety coating and prevent the safety coating from being separated in the needling process to cause direct contact between the aluminum foil and the negative active material.
Wherein the insulating material in the insulating layer comprises boehmite and Al2O3And PMMA. The binder is one or more of polyvinylidene fluoride and polyacrylic acid.
The second positive electrode active material in the positive electrode active layer is one or a mixture of more of lithium cobaltate, nickel cobalt manganese, lithium manganese phosphate and lithium iron phosphate, the second conductive agent is one or a mixture of more of conductive carbon black, carbon nano tubes and graphene, and the second adhesive is polyvinylidene fluoride.
The third purpose of the invention is that: aiming at the defects of the prior art, the lithium ion battery is provided, has good mechanical performance, can test the mechanical performance through needling, unilateral extrusion and foreign matter extrusion, and has good safety and long service life.
In order to achieve the purpose, the invention adopts the following technical scheme:
a lithium ion battery comprises the positive plate. Concretely, the lithium ion battery comprises a positive plate, a diaphragm, electrolyte, a shell and the positive plate.
The active material layer coated on the current collector of the negative plate can be one or more of graphite, soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, silicon-based materials, tin-based materials, lithium titanate or other metals capable of forming an alloy with lithium. Wherein, the graphite can be selected from one or more of artificial graphite, natural graphite and modified graphite; the silicon-based material can be one or more selected from simple substance silicon, silicon-oxygen compound, silicon-carbon compound and silicon alloy; the tin-based material can be one or more selected from simple substance tin, tin oxide compound and tin alloy. The negative electrode current collector is generally a structure or a part for collecting current, and the negative electrode current collector may be any material suitable for use as a negative electrode current collector of a lithium ion battery in the art, for example, the negative electrode current collector may include, but is not limited to, a metal foil, and the like, and more specifically, may include, but is not limited to, a copper foil, and the like.
And the separator may be various materials suitable for lithium ion battery separators in the art, and for example, may be one or a combination of more of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, natural fiber, and the like, including but not limited thereto.
The lithium ion battery also comprises electrolyte, and the electrolyte comprises an organic solvent, electrolyte lithium salt and an additive. Wherein the electrolyte lithium salt may be LiPF used in a high-temperature electrolyte6And/or LiBOB; or LiBF used in low-temperature electrolyte4、LiBOB、LiPF6At least one of; or LiBF used in anti-overcharge electrolyte4、LiBOB、LiPF6At least one of, LiTFSI; may also be LiClO4、LiAsF6、LiCF3SO3、LiN(CF3SO2)2At least one of (1). And the organic solvent may be a cyclic carbonate including PC, EC; or chain carbonates including DFC, DMC, or EMC; and also carboxylic acid esters including MF, MA, EA, MP, etc. And additives include, but are not limited to, film forming additives, conductive additives, flame retardant additives, overcharge prevention additives, control of H in the electrolyte2At least one of additives of O and HF content, additives for improving low temperature performance, and multifunctional additives. Wherein, the material of casing is the plastic-aluminum membrane.
Compared with the prior art, the invention has the beneficial effects that: according to the positive plate, the safety coatings are arranged on the surfaces of the two sides of the positive current collector, so that the bonding force between the positive current collector and the positive coating is increased, the positive current collector is prevented from contacting with the negative active coating to generate short circuit during a needling test, a single-side test and a foreign matter extrusion test, and the needling test, the single-side test and the foreign matter extrusion test pass rate are improved; and the safety coating has certain internal resistance, so that the internal resistance of the battery cell can be increased, the short-circuit current can be reduced, and the thermal shock performance and the external short-circuit resistance of the battery cell can be improved.
Drawings
Fig. 1 is a schematic view of the structure of the positive electrode sheet of the present invention.
Wherein: 1. a positive current collector; 2. a security coating; 3. an insulating layer; 4. and a positive electrode active layer.
Detailed Description
The present invention will be described in further detail below with reference to specific embodiments and drawings, but the embodiments of the present invention are not limited thereto.
Example 1
A preparation method of a lithium ion battery comprises the following steps:
1. preparation of the safety coating 2: lithium iron phosphate (LFP), conductive carbon, a carbon nano tube, PVDF and ceramics are mixed according to the weight part ratio of 90: 6.8: 8:2.5: 12, adding the positive active material, the inorganic filler, the conductive agent and the adhesive into a stirring tank in sequence, wherein the weight parts of the positive active material, the inorganic filler, the conductive agent and the adhesive are 90:5:2:3, the slurry of the safety coating 2 after stirring is 860mpa.s in viscosity, the slurry of the safety coating 2 after stirring is uniformly coated on a first coating area and a second coating area of a positive current collector 1 by gravure coating, the thickness of the current collector (aluminum foil) is 9 mu m, and the coating surface density is 12mg/1540.25mm2At this time, the sheet resistance was measured to be 0.13 Ω.
2. Preparation of the insulating layer 3: mixing 15g of alumina and 20g of adhesive (polyvinylidene fluoride) to prepare insulating slurry, coating the insulating slurry on a hollow foil area on the surface of a positive current collector 1, drying to form an insulating layer 3, and carrying out cold pressing on the prepared pole piece; and then trimming, cutting and slitting are carried out, drying is carried out for 4 hours at 110 ℃ under the vacuum condition after slitting, and the tab is welded to prepare a second substrate.
3. Preparation of positive electrode active layer 4: lithium cobaltate, conductive carbon black and a binder (polyvinylidene fluoride) are mixed according to the weight ratio of 96: 2.5: 1.5, uniformly mixing to prepare lithium ion battery anode slurry with certain viscosity, coating the slurry on a second substrate with a safety coating 2, and drying to form an anode active layer 4, wherein the sheet resistance of the anode sheet is 0.8 omega, as shown in fig. 1.
4. Preparing a lithium ion battery: winding the positive plate, the diaphragm and the negative plate into a battery cell, wherein the diaphragm is positioned between the positive plate and the negative plate, the positive electrode is led out by spot welding of an aluminum tab, and the negative electrode is led out by spot welding of a nickel tab; and then placing the battery core in an aluminum-plastic packaging bag, injecting electrolyte, and carrying out procedures of packaging, formation, capacity and the like to prepare the lithium ion battery.
Example 2
The difference from example 1 is that: the weight parts of the positive active substance, the inorganic filler, the conductive agent and the adhesive in the safety coating 2 are 87.4:6.8:2.5: 6.
The rest is the same as embodiment 1, and the description is omitted here.
Example 3
The difference from example 1 is that: the weight parts of the positive active substance, the inorganic filler, the conductive agent and the adhesive in the safety coating 2 are 88:13:2.5: 6.
The rest is the same as embodiment 1, and the description is omitted here.
Example 4
The difference from example 1 is that: the weight parts of the positive active substance, the inorganic filler, the conductive agent and the adhesive in the safety coating 2 are 88:18:0.5: 16.
The rest is the same as embodiment 1, and the description is omitted here.
Example 5
The difference from example 1 is that: the weight parts of the positive active substance, the inorganic filler, the conductive agent and the adhesive in the safety coating 2 are 88:21:0.8: 20.
The rest is the same as embodiment 1, and the description is omitted here.
Example 6
The difference from example 2 is that: the weight parts of the positive active material, the conductive agent and the adhesive in the positive active layer 4 are 95:2: 1.5.
The rest is the same as embodiment 2, and the description is omitted here.
Example 7
The difference from example 2 is that: the weight parts of the positive active substance, the conductive agent and the adhesive in the positive active layer 4 are 96:2: 2.
The rest is the same as embodiment 2, and the description is omitted here.
Example 8
The difference from example 2 is that: the weight parts of the positive active material, the conductive agent and the adhesive in the positive active layer 4 are 95:1: 2.
The rest is the same as embodiment 2, and the description is omitted here.
Example 9
The difference from example 2 is that: the weight parts of the positive active substance, the conductive agent and the adhesive in the positive active layer 4 are 98:3: 1.5.
The rest is the same as embodiment 2, and the description is omitted here.
Example 10
The difference from example 2 is that: the weight parts of the positive active material, the conductive agent and the adhesive in the positive active layer 4 are 97:3: 1.
The rest is the same as embodiment 2, and the description is omitted here.
Comparative example 1
The difference from example 1 is that: the security coating 2 is not present.
The rest is the same as embodiment 1, and the description is omitted here.
And (3) performance testing: the cells prepared in examples 1 to 10 and comparative example 1 were subjected to a needle punching test, a single side pressing test, an external short circuit (60m Ω), a pass rate of thermal shock (132 ℃), and a capacity retention rate test after 300 charge and discharge cycles. The test structure is reported in table 1.
TABLE 1
Figure BDA0003556695400000081
As can be seen from table 1 above, the positive electrode sheet of the present invention can improve the passage rates of the needle punching test, the single-side pressing test, the external short circuit (60m Ω), and the thermal shock (132 ℃), and has high passage rates of all the tests, good mechanical strength, and good safety performance, compared to the positive electrode sheet of comparative example 1. From comparison of examples 1 to 5, when the weight parts of the positive active material, the inorganic filler, the conductive agent and the adhesive in the safety coating layer 2 are 87.4:6.8:2.5:6, the prepared positive plate has good mechanical properties and safety properties. From comparison of examples 2 and 6-10, when the weight parts of the positive active material, the conductive agent and the adhesive in the positive active layer 4 are 95:2:1.5, the prepared positive plate has good mechanical properties and safety, and also has high capacity retention rate and particularly good electrochemical properties.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims (12)

1. A positive electrode sheet, comprising:
the surface of one side of the positive current collector is provided with a first coating area and a hollow foil area, the first coating area and the hollow foil area are arranged in parallel, and the surface of the other side of the positive current collector is provided with a second coating area;
the safety coating is arranged in the first coating area and the second coating area, and the resistance of the safety coating is 0.13-3 omega; the insulating layer is arranged in the empty foil area;
and a positive active layer disposed on an outer surface of the safety coating layer.
2. The positive electrode sheet according to claim 1, wherein the safety coating layer comprises a first positive electrode active material, an inorganic filler, a first conductive agent and a first binder, and the weight ratio of the first positive electrode active material to the inorganic filler to the first conductive agent to the first binder is 28-95.8: 3-50: 0.2-2: 1-20.
3. The positive electrode sheet according to claim 2, wherein the first positive electrode active material is one or more of lithium iron phosphate, lithium manganate, and lithium manganese iron phosphate, the inorganic filler is one or more of alumina, boehmite, silica, and titanium oxide, the first conductive agent is one or more of conductive carbon black, carbon nanotubes, graphene, and carbon fibers, and the first binder is one or more of polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, polytetrafluoroethylene, and polyvinyl alcohol.
4. The positive electrode sheet according to claim 1 or 2, wherein the safety coating layer has a coating areal density of 4 to 30mg/1540.25mm2。
5. The positive electrode sheet according to claim 1 or 2, wherein the safety coating layer comprises a first safety coating layer and a second safety coating layer, the first safety coating layer is disposed in the first coating region, and the second safety coating layer is disposed in the second coating region; the length of the first security coating is less than the length of the second security coating.
6. The positive electrode sheet according to claim 1, wherein the insulating layer comprises a first insulating material and a binder, the insulating material is one or more of alumina, boehmite, silica, titania, and polymethyl methacrylate, and the binder is one or more of polyvinylidene fluoride, styrene-butadiene rubber, polyacrylic acid, polytetrafluoroethylene, and polyvinyl alcohol.
7. The positive electrode sheet according to claim 6, wherein the difference in thickness between the insulating layer and the safety coating layer is less than or equal to 7 μm.
8. The positive electrode sheet according to claim 5, wherein the positive electrode active layer includes a first active layer and a second active layer, the first active layer is disposed on an outer surface of the first safety coating layer, the second active layer is disposed on an outer surface of the second safety coating layer, and a length of the first active layer is smaller than a length of the second active layer.
9. The positive electrode sheet according to claim 1, wherein the positive electrode active layer comprises a second positive electrode active material, a second conductive agent, and a second binder, and the weight ratio of the second positive electrode active material, the second conductive agent, and the second binder is 95-98: 1-3: 0.5-2.
10. The method for producing a positive electrode sheet according to any one of claims 1 to 9, comprising the steps of:
step S1, mixing and stirring the positive active substance, the inorganic filler, the conductive agent and the adhesive to prepare safety coating slurry, coating the safety coating slurry on a first coating area and a second coating area on the surface of the positive current collector, and drying to form a safety coating to obtain a first substrate;
step S2, mixing an insulating material and an adhesive to prepare insulating slurry, coating the insulating slurry on a hollow foil area on the surface of the positive current collector, and drying to form an insulating layer to prepare a second substrate;
and step S3, mixing and stirring the positive active substance, the conductive agent and the adhesive to prepare positive active slurry, coating the positive active slurry on the surface of the safety coating, and drying to form a positive active layer to obtain the positive plate.
11. The method for preparing the positive electrode sheet according to claim 10, wherein the drying temperature in the step S2 is 100 to 120 ℃ and the drying time is 4 to 6 hours.
12. A lithium ion battery comprising the positive electrode sheet according to any one of claims 1 to 9.
CN202210277758.4A 2021-12-23 2022-03-21 Positive plate, preparation method thereof and lithium ion battery Pending CN114583100A (en)

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CN115020634A (en) * 2022-06-06 2022-09-06 惠州锂威新能源科技有限公司 Safety coating, positive plate, preparation method of positive plate and secondary battery
CN116111096A (en) * 2023-04-11 2023-05-12 宁德新能源科技有限公司 Safety coating composition, positive electrode sheet, secondary battery and electronic device
CN116111096B (en) * 2023-04-11 2023-08-18 宁德新能源科技有限公司 Safety coating composition, positive electrode sheet, secondary battery and electronic device

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