CN116705985A - Sectional type lithium ion battery pole piece and secondary battery - Google Patents

Sectional type lithium ion battery pole piece and secondary battery Download PDF

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Publication number
CN116705985A
CN116705985A CN202310749635.0A CN202310749635A CN116705985A CN 116705985 A CN116705985 A CN 116705985A CN 202310749635 A CN202310749635 A CN 202310749635A CN 116705985 A CN116705985 A CN 116705985A
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pole piece
active material
positive electrode
negative
positive
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Inventor
安孝坤
刘逸群
张洁
高永涛
张儒超
姜雨良
陈睿
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Wanhua Chemical Sichuan Battery Material Technology Co ltd
Wanhua Chemical Yantai Battery Material Technology Co ltd
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Wanhua Chemical Sichuan Battery Material Technology Co ltd
Wanhua Chemical Yantai Battery Material Technology Co ltd
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Priority to CN202310749635.0A priority Critical patent/CN116705985A/en
Publication of CN116705985A publication Critical patent/CN116705985A/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
    • H01M4/13—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M2010/4292—Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
    • 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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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The application discloses a sectional lithium ion battery pole piece and a secondary battery, which comprises a positive pole piece and a negative pole piece, wherein the positive pole piece is divided into a plurality of areas by taking an end A as a starting point and an end B as an end point along the winding direction of the positive pole piece and the negative pole piece, the nickel content of positive pole active materials among the areas is gradually increased, the rolling thickness H1 of the positive pole active materials in the areas is the same, and the rolling thickness H2 of the negative pole piece active materials is gradually increased from the area 1' to the last area; the sectional lithium ion battery pole piece provided by the application provides a reasonable space for volume expansion and contraction in the charging and discharging process of the positive electrode active material, prevents stress concentration, has small rolling thickness at the central part of the negative electrode pole piece, has large rolling curvature, gradually increases the rolling thickness from inside to outside, gradually reduces the rolling curvature, is beneficial to preventing the negative electrode active material from falling off, and improves the cycle performance and the safety performance of the battery.

Description

Sectional type lithium ion battery pole piece and secondary battery
Technical Field
The application belongs to the technical field of lithium ion batteries, and particularly relates to a sectional type lithium ion battery pole piece and a secondary battery.
Background
The lithium ion battery is widely used in industries such as consumer electronics, electric tools, electric vehicles and the like, and has the advantages of high working voltage, high energy density, long cycle life, high power, environmental protection and the like. As lithium ion batteries are increasingly used, challenges are presented to higher energy densities and higher safety performance. The ternary positive electrode material with higher nickel content can improve the energy density of the battery core and reduce the cost of the battery core, but the gas yield of the battery core is increased in the charge and discharge process, the volume expansion and shrinkage phenomenon of the material is more serious, and meanwhile, the high nickel material needs to correspond to thicker rolling thickness of the negative electrode. The problems can increase the risk that the positive and negative electrode active materials fall off from the pole piece, so that the battery core has the problems of poor cycle performance, poor safety performance and the like.
Disclosure of Invention
The application aims to provide a sectional lithium ion battery pole piece, which is divided into a plurality of areas, so that the energy density of a battery core is effectively improved, and the capacity and the cycle performance of the battery are improved.
It is still another object of the present application to provide a secondary battery.
In order to achieve the aim of the application, the application adopts the following technical scheme:
the utility model provides a sectional type lithium ion battery pole piece, includes positive pole piece and negative pole piece, the positive pole piece includes positive pole current collector and positive pole active material, the negative pole piece includes negative pole current collector and negative pole active material, follows the coiling direction of positive pole piece and negative pole piece takes the A end as starting point B end as the terminal, the positive pole piece divide into a plurality of regions, from A end to B end in proper order name No. 1 region, no. 2 region, … …, no. N region, the nickel content of the positive pole active material between each region increases gradually, and the rolling thickness H1 of each regional positive pole active material is the same, and 15um is less than or equal to H1 is less than or equal to 35um, the negative pole piece divide into a plurality of regions, from A end to B end in proper order name No. 1 'region, no. 2' region, … …, no. N 'region, negative pole active material rolling thickness H2 increases gradually from No. 1' region to last region thickness.
Preferably, the method comprises the steps of,σ 1 the positive electrode surface density is 30-sigma 1 ≤40mg/cm 3 ，C 1 Gram capacity of positive electrode active material, mA.h/g, C 2 Is the gram capacity of the anode active material, mA.h/g, P is the compacted density of the anode active material, 1.5g/cm 3 ≤P≤1.7g/cm 3 H is the thickness of the negative current collector, and h is more than or equal to 6 mu m and less than or equal to 10 mu m.
In some embodiments of the application, the positive electrode active material is LiNi x Co y Mn z A k O 2 Wherein element a is one or more of Ti, mg, sr, la, zr, al, Y, W, preferably Ti, sr, zr, al, Y. Wherein x is more than or equal to 0.33 and less than or equal to 0.9, y is more than or equal to 0 and less than or equal to 0.33,0, z is more than or equal to 0.33,0, k is more than or equal to 0.33, and x+y+z+k=1.
In some embodiments of the present application, 0.33.ltoreq.x.ltoreq.0.5 for the positive electrode active material in region 1, 0.5 < x.ltoreq.0.95 for the positive electrode material in region N of the last region.
N is the number of regions of the positive electrode plate, N' is the number of regions of the negative electrode plate, and in some embodiments of the application, the positive electrode plate is divided into 2-5 regions altogether; the negative electrode sheet is divided into 2-5 regions, namely, n=2-5,N' =2-5. The number of regions of the positive electrode sheet may be the same as or different from the number of regions of the negative electrode sheet, and preferably, the number of regions of the positive electrode sheet is the same as the number of regions of the negative electrode sheet.
In some embodiments of the present application, the positive electrode active material is divided into 3 regions, region 1 having 0.33.ltoreq.x.ltoreq.0.5, region 2 having 0.5 < x.ltoreq. 0.8,3 having 0.7 < x.ltoreq.0.95.
Preferably, the positive electrode active material LiNi of region No. 1 x Co y Mn z A k O 2 The nickel content x satisfies 0.33.ltoreq.x.ltoreq.0.5, and x+y+z+k=1, and may be, for example, 0.33, 0.4, 0.45, 0.5, but not limited to the values recited, but other values not recited in the numerical range are equally applicable.
Preferably, the positive electrode active material LiNi of No. 2 region x Co y Mn z A k O 2 The nickel content x satisfies 0.5 < x.ltoreq.0.8, and x+y+z+k=1, for example, may be 0.55, 0.6, 0.7, 0.8, but is not limited to the values recited, and other values not recited in the numerical range are equally applicable.
Preferably, the positive electrode active material LiNi of No. 3 region x Co y Mn z A k O 2 The nickel content x satisfies 0.7 < x.ltoreq.0.95, and x+y+z+k=1, for example, may be 0.83, 0.88, 0.90, 0.95, but is not limited to the values recited, and other values not recited in the numerical range are equally applicable.
Preferably, the rolling thickness H1 of the positive electrode plate active material is more than or equal to 20 mu m and less than or equal to 25 mu m.
Preferably, the negative active material is selected from one or more of natural graphite, artificial graphite, hard carbon, soft carbon, silicon carbon, mesophase carbon microspheres, or silicon.
Preferably, the separator may be any one of a single-layer PP film, a single-layer PE film, a double-layer PP/PE film, and a multi-layer film.
Specifically, when the electrode plate body is a negative electrode plate, the corresponding current collector is a negative electrode current collector, and may specifically be a conventional current collector in a lithium ion battery, such as a stamped metal, a metal foil (e.g., copper foil, aluminum foil, etc.), a mesh metal, and a foam metal, preferably a copper foil. The negative electrode plate further comprises a negative electrode conductive agent and a negative electrode binder, and preferably, the mass ratio of the negative electrode active material to the negative electrode conductive agent to the negative electrode binder is 95-97:1-2:2-3. The anode conductive agent is not particularly limited, and may be an anode conductive agent conventional in the art, such as conductive carbon, carbon nanotube, graphene, nickel powder, copper powder, or the like; the negative electrode binder may be a fluorine-containing resin or a polyolefin compound such as one or more of styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), hydroxypropyl methylcellulose, hydroxyethyl cellulose, or polyvinyl alcohol.
Specifically, when the electrode plate body is an anode electrode plate, the corresponding current collector is an anode current collector, and may specifically be a conventional current collector in a lithium ion battery, such as a stamped metal, a metal foil (e.g., copper foil, aluminum foil, etc.), a mesh metal, and a foam metal, preferably an aluminum foil. The positive electrode sheet further comprises a positive electrode conductive agent, a positive electrode binder and a solvent, and preferably, the mass ratio of the positive electrode active material to the positive electrode conductive agent to the positive electrode binder is 95-97:1-2:1-3; the addition amount of the solvent is 0.3-50 times of the mass of the positive electrode active material. The positive electrode conductive agent is not particularly limited, and may be one or more of conductive carbon black, superconductive carbon black, conductive graphite, acetylene black, or carbon nanotubes, which are conventional in the art; the positive electrode binder can be one or more of polyvinyl alcohol binder, polyurethane binder, polyolefin acid ester binder, polyvinylidene fluoride binder, butyl rubber binder, epoxy resin binder, vinyl acetate resin binder or chlorinated rubber binder; the solvent is an organic solvent, and the organic solvent is one or more selected from heterocyclic compounds, such as: tetrahydrofuran, pyridine, N-methylpyrrolidone or pyrrole.
The application further aims to provide a battery, which comprises a battery pole piece, a diaphragm and electrolyte, wherein the battery pole piece is the lithium ion battery pole piece provided by the application.
The application has the following beneficial effects:
the application adopts a sectional coating technology to divide the pole piece into three areas, reasonably distributes the nickel content of the ternary positive electrode active material in each area of the positive electrode pole piece, gradually increases the nickel content of the active material from the center to the periphery of the winding core, effectively improves the energy density of the battery core, simultaneously provides reasonable space for volume expansion and contraction in the charging and discharging process of the positive electrode active material, prevents stress concentration, solves the problems of low capacity of a single low-nickel positive electrode active material, high gas production of a single high-nickel positive electrode active material and the like, and improves the capacity and the cycle performance of the battery. The three areas of the negative pole piece are different in rolling thickness, the rolling thickness of the central part of the winding core with the largest winding curvature is small, and the rolling thickness of the edge part of the winding core with the smallest winding curvature is large, so that the active material is prevented from falling off the pole piece, and the cycle performance of the battery is improved.
Drawings
Fig. 1 is a schematic diagram of a sectional lithium ion battery pole piece structure according to the present application.
Detailed Description
The following examples are provided for a better understanding of the present application and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the application, any product which is the same or similar to the present application, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present application.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
The embodiment of the application provides a cylindrical battery, which comprises a negative electrode plate, a positive electrode plate, a diaphragm and electrolyte; the positive electrode plate comprises a positive electrode current collector and a positive electrode coating which is arranged on at least one surface of the positive electrode current collector and comprises a positive electrode active material, wherein the positive electrode coating comprises the positive electrode active material, a conductive agent and a binder; the negative electrode plate comprises a negative electrode current collector and a negative electrode coating which is arranged on at least one surface of the negative electrode current collector and comprises a negative electrode active material, wherein the negative electrode coating comprises the negative electrode active material, a conductive agent and a binder; the types of the positive/negative electrode current collectors are not particularly limited, and may be selected according to actual requirements.
Mixing an anode active material, a conductive agent and a binder, adding a solvent, homogenizing, coating on the surface of an anode current collector, and drying and rolling to obtain an anode sheet; mixing a negative electrode active substance, a conductive agent and a binder, adding a solvent, homogenizing, coating on the surface of a negative electrode current collector, drying and rolling to obtain a negative electrode plate, cutting, drying and welding a tab, preparing a positive electrode plate, a diaphragm and the negative electrode plate into a winding core through a winding machine, and then, putting the winding core into a shell, injecting liquid and a cap to obtain the lithium ion cylindrical battery.
Example 1:
preparing a positive electrode plate: 3 positive electrode active materials LiNi 0.50 Co 0.20 Mn 0.30 O 2 、LiNi 0.80 Co 0.10 Mn 0.10 O 2 、LiNi 0.90 Co 0.05 Mn 0.05 O 2 Adding the aluminum foil with conductive agent superconducting carbon, carbon tube and adhesive polyvinylidene fluoride according to the mass ratio of 97.6:0.6:0.5:1.3, adding solvent N-methyl pyrrolidone with the mass of 0.5 times of the positive electrode active material, uniformly mixing to prepare positive electrode slurry, dividing the positive electrode current collector aluminum foil into 3 areas, respectively marking the areas as the area No. 1, the area No. 2 and the area No. 3, respectively coating the 3 positive electrode slurry on the surfaces of the area No. 1, the area No. 2 and the area No. 3 of the current collector aluminum foil by adopting a step-by-step double-sided coating technology, wherein the coating surface density is 35mg/cm 2 Rolling to a thickness of 22.3 micrometers, drying and rolling at 85 ℃, and then carrying out cold pressing treatment on the positive plate with the positive active material layers coated on both sides; and then trimming, cutting and slitting are carried out to prepare the positive pole piece of the lithium ion battery.
Preparing a negative electrode plate: mixing negative electrode active material artificial graphite, conductive carbon black, thickener sodium carboxymethylcellulose and binder styrene-butadiene rubber according to the mass ratio of 96.5:1.5:1.0:2.0 to obtain lithium ion with preset viscosityThe method comprises the steps of dividing an 8-micrometer negative current collector copper foil into 3 areas, respectively marking the areas as an area No. 1, an area No. 2 and an area No. 3, coating the negative current collector copper foil with the negative current collector slurry by adopting a step-by-step double-sided coating technology, and adopting a formulaThe rolling thickness of each region of the negative electrode plate can be calculated, wherein the surface density of the positive electrode plate is 35mg/cm 2 ，LiNi 0.50 Co 0.20 Mn 0.30 O 2 The gram capacity is 155mAh/g, liNi 0.80 Co 0.10 Mn 0.10 O 2 The gram capacity is 194mAh/g, liNi 0.90 Co 0.05 Mn 0.05 O 2 The gram capacity is 203mAh/g, and the compacted density of the negative electrode is 1.5g/cm 3 The thickness of the copper foil is 8 micrometers, all parameters are brought into a formula, the rolling thickness of a No. 1 area is 19.7 micrometers, the rolling thickness of a No. 2 area is 22.6 micrometers, the rolling thickness of a No. 3 area is 23.3 micrometers, the copper foil is dried and rolled at the temperature of 85 ℃, and then the negative electrode sheet with the negative electrode active material layers coated on both sides is subjected to cold pressing treatment; and then trimming, cutting and slitting are carried out to prepare the lithium ion battery negative plate.
Preparation of a battery: winding the positive pole piece, the negative pole piece and the diaphragm into a winding core, winding the winding direction from the No. 1 area to the No. 3 area, arranging a PE diaphragm between the adjacent positive pole piece and negative pole piece, leading out the positive pole by aluminum tab spot welding, leading out the negative pole by nickel tab spot welding, placing the winding core into a steel shell, baking, injecting electrolyte, and finally manufacturing the lithium ion battery through the procedures of packaging, formation, capacity division and the like.
Example 2:
a lithium ion battery was fabricated by the same method as in example 1, with the main difference that: 3 positive electrode active materials are replaced with LiNi 0.34 Co 0.33 Mn 0.33 O 2 、LiNi 0.60 Co 0.10 Mn 0.30 O 2 、LiNi 0.83 Co 0.12 Mn 0.05 O 2 The coating surface density of the positive electrode plate is 40mg/cm 2 Rolling thickness of 25.8 micrometers, rolling No. 1 area of the negative electrode plateThe thickness was 20.1 microns, the rolling thickness of the No. 2 area was 22.3 microns, the rolling thickness of the No. 3 area was 23.9 microns, and the other methods were the same as in example 1, and will not be repeated here.
Example 3
A lithium ion battery was fabricated by the same method as in example 1, with the main difference that: 3 positive electrode active materials are replaced with LiNi 0.50 Co 0.20 Mn 0.30 O 2 、LiNi 0.65 Co 0.10 Mn 0.25 O 2 、LiNi 0.78 Co 0.12 Mn 0.10 O 2 The coating surface density of the positive electrode plate is 30mg/cm 2 The rolling thickness is 20.8 micrometers, the rolling thickness of the No. 1 area of the negative electrode plate is 18.0 micrometers, the rolling thickness of the No. 2 area is 20.8 micrometers, the rolling thickness of the No. 3 area is 22.4 micrometers, and other methods are the same as those of the embodiment 1 and are not repeated here.
Example 4
A lithium ion battery was fabricated by the same method as in example 1, with the main difference that: dividing the positive current collector aluminum foil into 2 regions, respectively marking the regions as a region 1 and a region 2, wherein the positive active materials of the region 1 and the region 2 are respectively LiNi 0.50 Co 0.20 Mn 0.30 O 2 、LiNi 0.80 Co 0.10 Mn 0.10 O 2 The 8-micron negative current collector copper foil is divided into 2 areas, which are respectively marked as a No. 1 area and a No. 2 area, and the rolling thickness after coating is respectively 19.7 microns and 22.6 microns, and other methods are the same as in the embodiment 1 and are not repeated here.
Comparative example 1:
a lithium ion battery was fabricated by the same method as in example 1, with the main difference that: unlike example 1, the following is: substitution of 3 positive electrode active materials with 1 positive electrode active material LiNi 60 Co 10 Mn 30 O 2 Other methods are the same as in embodiment 1, and will not be described here again.
Comparative example 2:
unlike example 1, the following is: substitution of 3 positive electrode active materials with 1 positive electrode active material LiNi 90 Co 05 Mn 05 O 2 Other methods are the same as in embodiment 1, and will not be described here again.
Comparative example 3:
a lithium ion battery was fabricated by the same method as in example 1, with the main difference that: the rolling thickness of the No. 1 region of the negative plate is 15 micrometers, the rolling thickness of the No. 2 region is 18 micrometers, and the rolling thickness of the No. 3 region is 20 micrometers, and other methods are the same as those of the embodiment 1, and are not repeated here.
The rate performance and cycle performance of the battery were tested as follows: and (3) multiplying power performance test:
the lithium batteries prepared in examples 1 to 4 and comparative examples 1 to 2 were charged at a rate of 0.3C, and discharged at rates of 0.5C, 1.0C, 0.5C, 2.0C, 4.0C, and 8.0C, respectively, and the discharge capacities and capacity retention rates are shown in table 1.
And (3) testing the cycle performance:
the lithium batteries prepared in examples 1 to 4 and comparative examples 1 to 2 were charged at a rate of 2.0C and discharged at a rate of 2.0C, and were cycled 500 times, and initial capacities, capacities after 500 cycles, and capacity retention rates are shown in table 1.
As can be seen from the electrochemical data of examples 1-4 and comparative examples 1-2, the battery made of the segmented lithium ion battery pole piece has higher capacity than the single low-nickel-content positive electrode active material pole piece, better cycle than the single high-nickel-content positive electrode active material pole piece, and optimal comprehensive performance, and the comparative example 3 has the advantages of small rolling thickness of the negative electrode, less negative electrode quantity, lithium dendrite phenomenon of the negative electrode in the charging and discharging process, and failure of short circuit in the battery.

Claims (10)

1. The sectional lithium ion battery pole piece comprises a positive pole piece and a negative pole piece, and is characterized in that the positive pole piece comprises a positive pole current collector and a positive pole active material, the negative pole piece comprises a negative pole current collector and a negative pole active material, an A end is taken as a starting point, a B end is taken as an end point along the winding direction of the positive pole piece and the negative pole piece, the positive pole piece is divided into a plurality of areas, the areas are sequentially named as an area 1 from the A end to the B end, an area 2 and an area … …, the nickel content of the positive pole active material between the areas is gradually increased, the rolling thickness H1 of the positive pole active material in each area is the same, the H1 is less than or equal to 15 mu m and less than or equal to 35 mu m, the negative pole piece is divided into a plurality of areas, the rolling thickness H2 of the negative pole piece is sequentially named as an area 1' from the A end to the B end, an area 2' and an area … …, and the thickness H2 of the negative pole active material is gradually increased from the area 1' to the last area;
n is the number of regions of the positive pole piece, and N' is the number of regions of the negative pole piece.
2. The battery pole piece of claim 1, wherein the battery pole piece comprises a plurality of electrodes,σ 1 the positive electrode surface density is 30-sigma 1 ≤40mg/cm 3 ，C 1 Gram capacity of positive electrode active material, mA.h/g, C 2 Is the gram capacity of the anode active material, mA.h/g, P is the compacted density of the anode active material, 1.5g/cm 3 ≤P≤1.7g/cm 3 H is the thickness of the negative current collector, and h is more than or equal to 6 mu m and less than or equal to 10 mu m.
3. The battery pole piece of claim 1, wherein the positive electrode active material is LiNi x Co y Mn z A k O 2 Wherein element a is one or more of Ti, mg, sr, la, zr, al, Y, W, preferably one or more of Ti, sr, zr, al, Y;
wherein x is more than or equal to 0.33 and less than or equal to 0.9, y is more than or equal to 0 and less than or equal to 0.33,0, z is more than or equal to 0.33,0, k is more than or equal to 0.33, and x+y+z+k=1.
4. The battery pole piece of claim 1, wherein x is 0.33.ltoreq.x.ltoreq.0.5 for the positive electrode active material of region 1, and x is 0.5 < x.ltoreq.0.95 for the positive electrode active material of region N of the last region.
5. The battery pole piece of claim 1, wherein the positive pole piece is divided into 2-5 regions altogether; the negative electrode plate is divided into 2-5 areas, namely N=2-5,N' =2-5;
preferably, the number of regions of the positive electrode sheet is the same as or different from the number of regions of the negative electrode sheet,
more preferably, the number of regions of the positive electrode tab is the same as the number of regions of the negative electrode tab.
6. The battery pole piece of claim 1, wherein the positive electrode active material is divided into 3 regions, no. 1 region 0.33 x 0.5, no. 2 region 0.5 < x 0.8,3 region 0.7 < x 0.95.
7. The battery pole piece of claim 1, wherein the positive pole piece active material rolled thickness is 20 μm or less and H1 μm or less and 25 μm or less.
8. The battery pole piece of claim 1, wherein the negative active material is selected from one or more of natural graphite, artificial graphite, hard carbon, soft carbon, silicon carbon, mesophase carbon microspheres, or silicon;
the negative current collector is selected from a stamped metal, a metal foil, a reticulated metal or a foam metal, preferably copper foil;
preferably, the negative electrode plate further comprises a negative electrode conductive agent and a negative electrode binder;
more preferably, the mass ratio of the anode active material, the anode conductive agent and the anode binder is 95 to 97:1-2:2-3;
preferably, the negative electrode conductive agent is selected from conductive carbon, carbon nanotubes, graphene, nickel powder or copper powder;
preferably, the negative electrode binder is a fluorine-containing resin or a polyolefin compound, and is one or more selected from styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinylidene fluoride, polytetrafluoroethylene, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and polyvinyl alcohol.
9. The battery pole piece of claim 1, wherein the positive current collector is selected from the group consisting of stamped metal, metal foil, reticulated metal or foam metal, preferably aluminum foil;
preferably, the positive electrode sheet further comprises a positive electrode conductive agent, a positive electrode binder and a solvent;
preferably, the mass ratio of the positive electrode active material, the positive electrode conductive agent and the positive electrode binder is 95-97:1-2:1-3; the addition amount of the solvent is 0.3-10 times of the mass of the positive electrode active material;
preferably, the positive electrode conductive agent is selected from one or more of conductive carbon black, superconductive carbon black, conductive graphite, acetylene black or carbon nanotubes; the positive electrode binder can be one or more of polyvinyl alcohol binder, polyurethane binder, polyolefin acid ester binder, polyvinylidene fluoride binder, butyl rubber binder, epoxy resin binder, vinyl acetate resin binder or chlorinated rubber binder; the solvent is selected from organic solvents, and the organic solvents are selected from one or more of heterocyclic compounds, preferably tetrahydrofuran, pyridine, N-methylpyrrolidone or pyrrole.
10. A secondary battery comprising a battery pole piece, a separator and an electrolyte, the battery pole piece being a lithium ion battery pole piece according to any one of claims 1-9.
CN202310749635.0A 2023-06-25 2023-06-25 Sectional type lithium ion battery pole piece and secondary battery Pending CN116705985A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117038860A (en) * 2023-10-10 2023-11-10 宁德时代新能源科技股份有限公司 Cathode plate, electrode assembly, battery and electric equipment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117038860A (en) * 2023-10-10 2023-11-10 宁德时代新能源科技股份有限公司 Cathode plate, electrode assembly, battery and electric equipment
CN117038860B (en) * 2023-10-10 2024-04-05 宁德时代新能源科技股份有限公司 Cathode plate, electrode assembly, battery and electric equipment

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