CN114373927A - Negative electrode material and negative electrode plate comprising same - Google Patents

Negative electrode material and negative electrode plate comprising same Download PDF

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Publication number
CN114373927A
CN114373927A CN202111652704.3A CN202111652704A CN114373927A CN 114373927 A CN114373927 A CN 114373927A CN 202111652704 A CN202111652704 A CN 202111652704A CN 114373927 A CN114373927 A CN 114373927A
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negative electrode
particle size
graphite powder
volume
electrode material
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陈若凡
刘春洋
李素丽
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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/133—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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative 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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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a negative electrode material and a negative electrode plate comprising the same, wherein the negative electrode material comprises graphite powder, and the particle size and the powder compaction of the graphite powder meet the following conditions: 1 ≤ Dv99-Dv10-1.6Dv50+ PD2Less than or equal to 5.21; dv99/Dv50 is not less than 1.87 and not more than 2.48. Wherein: dv50 represents a particle size of the graphite at which 50% of the volume is accumulated from a small particle size side in a volume-based particle size distribution; dv99 represents a particle size of the graphite when the volume accumulation reaches 99% from a small particle size side in a volume-based particle size distribution; dv10 represents a particle size at which the graphite particles reach a volume cumulative 10% from a small particle size side in a volume-based particle size distribution; PD refers to powder compaction of graphite powder. The lithium ion battery prepared by the cathode material has high and multiple energy densityGood rate performance and low impedance.

Description

Negative electrode material and negative electrode plate comprising same
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative electrode material and a negative electrode plate comprising the same.
Background
The energy density is always improved in the direction of continuous research of lithium ion batteries, and along with the continuous development of application scenes of electronic products, the requirements on the rate capability are continuously improved at present except for the aspect of improving the energy density. The compaction of the negative pole piece is an effective way for improving the energy density of the lithium ion battery, but the porosity of the negative pole piece can be attenuated after the compaction of the negative pole piece is improved, so that the reduction of the charging performance of the lithium ion battery is inhibited, and the lithium analysis condition is easily caused. Therefore, the lithium ion battery is difficult to realize high energy density and high rate performance.
Disclosure of Invention
In order to solve the technical problems, the invention provides a negative electrode material and a negative electrode plate comprising the negative electrode material, wherein the negative electrode plate has effectively improved rate capability while considering energy density, and a battery comprising the negative electrode plate has quick charging performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
a negative electrode material comprising graphite powder, the particle size and powder compaction of the graphite powder satisfying the following conditions:
-1≤Dv99-Dv10-1.6Dv50+PD2≤5.21
1.87≤Dv99/Dv50≤2.48
wherein:
dv50 represents the particle size of the graphite powder when the volume accumulation reaches 50% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
dv99 represents the particle size of the graphite powder when the volume accumulation reaches 99% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
dv10 represents the particle size of the graphite powder when the volume accumulation reaches 10% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
PD refers to the powder compaction of graphite powder, unit: g/cm3。
According to the invention, the particle size and the powder compaction of the graphite powder satisfy the following conditions:
2.7≤Dv99-Dv10-1.6Dv50+PD2≤4.2
2.1≤Dv99/Dv50≤2.35
dv50, Dv99, Dv10 and PD are as defined above.
According to the invention, the Dv50 of the graphite powder satisfies: dv50 is more than or equal to 12 mu m and less than or equal to 14.6 mu m.
According to the invention, the Dv99 of the graphite powder satisfies: dv99 is more than or equal to 25 mu m and less than or equal to 31 mu m.
According to the invention, the Dv10 of the graphite powder satisfies: dv10 is less than or equal to 7.0 mu m and less than or equal to 9.1 mu m.
According to the invention, the PD of the graphite powder is 1.9-2.05 g/cm3。
The invention also provides a negative pole piece which comprises the negative pole material.
According to the invention, the negative pole piece comprises a negative pole current collector and a negative pole active material layer positioned on at least one side surface of the negative pole current collector, wherein the negative pole active material layer comprises a negative pole active material, and the negative pole active material comprises the negative pole material.
According to the invention, the porosity of the negative pole piece is 18.3% -30%.
According to the invention, the OI value of the negative pole piece is 12-25.
According to the invention, the single-sided paste coating thickness d of the negative pole piece meets the following requirements: 0.9Dv 99. ltoreq. d.ltoreq.5.5 Dv50, Dv99 and Dv50 being as defined above.
The invention also provides a lithium ion battery which comprises the negative electrode material and/or the negative electrode pole piece.
The invention has the advantages of
The compaction for improving the negative pole piece is an effective mode for improving the energy density of the lithium ion battery, but the porosity of the negative pole piece can cause attenuation after the compaction of the negative pole piece is improved, so that the improvement of the charging performance of the lithium ion battery is inhibited, and the lithium analysis condition is easily caused. The applicant of the present invention found through a great deal of research that: when the particle size distribution characteristics of the used negative electrode material and the used compaction matching meet certain conditions, the energy density of the prepared battery core is highest under the condition of supporting high multiplying power.
The lithium ion battery prepared by the cathode material has the characteristics of high energy density, good rate capability and low impedance.
Detailed Description
As described above, the present invention provides an anode material comprising graphite powder having a particle diameter and powder compaction satisfying the following conditions:
-1≤Dv99-Dv10-1.6Dv50+PD2≤5.21
1.87≤Dv99/Dv50≤2.48
wherein Dv50, Dv99, Dv10 and PD are as defined above.
According to the invention, the particle size and the powder compaction of the graphite powder satisfy the following conditions:
2.7≤Dv99-Dv10-1.6Dv50+PD2≤4.2
2.1≤Dv99/Dv50≤2.35
wherein Dv50, Dv99, Dv10 and PD are as defined above.
In the present invention, the material particle size distribution (Dv10, Dv50, Dv99) was tested using a malvern 3000(MS3000) apparatus; the thickness of the negative electrode active material layer was measured using a micrometer screw.
According to the invention, the Dv50 of the graphite powder satisfies: 12 μm Dv50 ≦ 14.6 μm, illustratively 12 μm, 12.245 μm, 12.297 μm, 12.455 μm, 13.0 μm, 13.5 μm, 14.526 μm, or 14.6 μm.
According to the invention, the Dv99 of the graphite powder satisfies: 25 μm.ltoreq.Dv 99.ltoreq.31 μm, exemplary 25.0 μm, 26.074 μm, 27 μm, 28 μm, 29.265 μm, 30.916 μm or 31 μm.
According to the invention, the Dv10 of the graphite powder satisfies: 7.0 μm.ltoreq.Dv 10.ltoreq.9.1 μm, exemplary 7.0 μm, 7.377 μm, 8.995 μm, 9.028 μm or 9.1 μm.
According to the invention, the PD of the graphite powder is 1.9-2.05 g/cm3Exemplary is 1.9g/cm3、1.93g/cm3、1.95g/cm3、1.97g/cm3、1.99g/cm3、2.01g/cm3、2.03g/cm3Or 2.05g/cm3。
According to the invention, the negative electrode material consists of the graphite powder.
The invention also provides application of the negative electrode material in a negative electrode plate. Preferably as the negative active material of the negative pole piece.
The invention also provides a negative pole piece which comprises the negative pole material.
According to the invention, the negative pole piece comprises a negative pole current collector and a negative pole active material layer positioned on at least one side surface of the negative pole current collector, wherein the negative pole active material layer comprises a negative pole active material, and the negative pole active material comprises the negative pole material.
According to the invention, the mass content of the negative electrode material in the negative electrode plate is 95.3-98%.
According to the invention, the porosity of the negative electrode sheet is 18.3% to 30%, illustratively 18.3%, 18.5%, 20%, 25%, 28%, 30% or any point in the range of the aforementioned two-by-two values.
According to the invention, the OI value of the negative electrode pole piece is 12-25, and is exemplified by 12, 15, 18, 20, 22, 25 or any point value in the range of the two numerical values.
According to the invention, the single-sided paste coating thickness d (unit: mum) of the negative pole piece meets the following requirements: d is not less than 0.9Dv99 and not more than 5.5Dv 50; wherein Dv99 and Dv55 are as defined above.
According to the invention, the surface density of the negative pole piece can meet the 3C charging performance.
The rate capability of a lithium ion battery is closely related to the electrochemical impedance of the lithium ion battery, and generally, the rate capability of the battery is more excellent when the electrochemical impedance is smaller. In the research process, when the particle size distribution and the compaction performance of the negative electrode material meet the relational expression, the lithium-ion battery can give consideration to the optimal volume energy density and rate capability. When the electrochemical impedance is expressed, the electrochemical impedance is significantly lowered.
The research of the invention finds that the particle size distribution of the material is closely related to the electrochemical impedance and the compaction performance of the material, the particle size distribution of the material is normally distributed, not every particle exists in a uniform spherical shape, and Dv99 represents the existence of larger particles in the particle size distribution. Use the negative pole piece of the great negative pole material preparation of granule particle diameter, the surface is uneven distribution state under the micro condition, the position that the large granule exists forms stress concentration point easily, in electric core charge-discharge process, stress concentration point exists the risk of preferred inflation tympanites, can form the space between diaphragm and the pole piece this moment, after lithium ion passes from the diaphragm, because the problem in space, can't reach the active material surface and inlay lithium, thereby cause lithium dendrite growth between diaphragm and pole piece interface, cause the capacity decay condition.
On the other hand, the invention unexpectedly discovers that when the using amount of large particles of the negative electrode material is simply controlled, the powder compaction of the material is reduced, and after the powder compaction of the material is reduced, the compaction of the negative electrode pole piece is reduced. Namely, under the same capacity condition, a larger thickness of the negative pole piece is needed, thereby causing the reduction of the cell energy density.
According to the invention, through a great deal of research on the negative electrode material powder and the battery cell prepared from the negative electrode powder, the internal correlation between the Dv50 and Dv99 of the powder material and the powder compaction (PD) of the material is found out unexpectedly. The battery cell prepared from the negative electrode material meeting the relationship of the invention can meet the requirement of high energy density under the condition of supporting high-rate charging. Meanwhile, the particle size distribution of the negative electrode material can be controlled and the compaction performance of the material powder can be predicted through the rule.
According to the present invention, the anode active material layer further optionally includes a conductive agent and/or a binder and/or a thickener.
Preferably, in the negative electrode plate, the mass content of the negative electrode active material is 95.3-98%, the mass content of the conductive agent is 0-3%, the mass content of the binder is 0.5-4%, and the mass content of the thickening agent is 0.5-3%.
Preferably, the conductive agent is selected from at least one of superconducting carbon black (SP), graphene, carbon nanotubes, fullerene, graphene nanoribbon, lamellar graphite (such as KS-6 flake graphite), and the like, wherein the carbon nanotubes may include single-walled carbon nanotubes and/or multi-walled carbon nanotubes;
preferably, the binder is selected from at least one of vinylidene fluoride (PVDF), a copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and Styrene Butadiene Rubber (SBR).
Preferably, the thickener is selected from sodium carboxymethylcellulose (CMC-Na).
The invention also provides a preparation method of the negative pole piece, which comprises the steps of putting the negative pole active material, the optionally added or not added conductive agent, the binder and the thickening agent into a solvent (deionized water) according to the mass ratio to prepare negative pole slurry, coating the negative pole slurry on at least one side surface of the negative pole current collector, and forming a negative pole active material layer on at least one side surface of the negative pole current collector after drying and rolling to obtain the negative pole piece.
The invention also provides application of the negative electrode material and/or the negative electrode plate in a lithium ion battery.
The lithium ion battery of the present invention can be prepared according to a conventional method in the art, for example, the lithium ion battery can be prepared by stacking a positive plate, a diaphragm, and a negative plate in sequence, winding (or stacking) the stacked positive plates, the diaphragm, and the negative plate to form a cell, and then performing processes such as packaging, cell baking, electrolyte injection (i.e., electrolyte injection), and hot pressing.
The invention also provides a lithium ion battery which comprises the negative electrode material and/or the negative electrode plate.
According to the invention, the lithium ion battery further comprises a positive plate.
Preferably, the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer coated on one or both surfaces of the positive electrode collector.
Preferably, the positive electrode active material layer includes a positive electrode active material, a conductive agent, and a binder;
according to an exemplary embodiment of the present invention, the mixing mass ratio of the positive electrode active material, the conductive agent, and the binder is (94 to 99.6): (0.2-3): (0.2-3).
According to the present invention, the positive electrode active material is at least one selected from lithium cobaltate, lithium manganate, lithium nickelate, lithium Nickel Cobalt Manganese (NCM), lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium-rich manganese-based materials, lithium nickel cobalt aluminate, and the like. The lithium nickel cobalt manganese oxide (NCM) may include at least one of NCM111, NCM523, NCM532, NCM622, and NCM811, for example.
According to the present invention, the conductive agent in the positive electrode active material layer is selected from at least one of Acetylene Black (AB), conductive carbon black (Super-P), Ketjen Black (KB), Carbon Nanotube (CNT), and graphene.
According to the present invention, the binder in the positive electrode active material layer may be selected from at least one of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC-Na), and Sodium Alginate (SA).
The technical solution of the present invention will be further described in detail with reference to specific embodiments. 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.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
The following examples and comparative examples of the present invention:
(1) thickness of the pole piece: the test was performed using a Japan Sanfeng digital micrometer.
(2) Porosity: the test was performed using a macaccupyc II 1340 true density instrument.
(3) OI value: placing the rolled negative plate on an X-ray powder diffractometer Shimadzu XRD for detection, and using the intensity ratio of the graphite characteristic peak (004)/(110) as an OI value, namely I004/I110。
(4) Volumetric energy density
Volume energy density is initial capacity/cell volume (if the cell is a rectangular solid, the cell volume is long, wide, and high)
After being charged to the upper limit voltage (4.48V) of the battery cell at room temperature at a constant current and a constant voltage of 0.5C, the initial capacity is the capacity discharged when the battery cell is discharged to 3V at a current of 0.2C.
(5) Capacity retention rate test method:
at room temperature, after charging to the upper limit voltage (4.48V) of the battery cell by using a constant current and a constant voltage of 0.5C, the capacity discharged when discharging to 3V by using a current of 0.2C is taken as the initial capacity C1;
at room temperature, charging at a rate of 3C, discharging at a rate of 1C, circulating for 20 times, and then performing one-time charging and discharging on the battery cell at a rate of 0.5C/0.5C to obtain a discharge capacity of C2;
capacity retention rate ═ C2/C1 × 100%.
Examples 1 to 3 and comparative examples 1 to 5
In examples 1 to 3 and comparative examples 1 to 5, the negative electrode sheet, the positive electrode sheet, and the lithium ion battery were prepared as follows:
(1) preparing a negative plate: placing graphite, SBR, superconducting carbon black and CMC in deionized water according to the mass ratio of 97:1.0:0.5:1.5 to prepare negative electrode slurry; coating the negative electrode slurry on the front surface and the back surface of a negative electrode current collector (copper foil) by using a coating machine, and forming negative electrode active material layers on the front surface and the back surface of the negative electrode current collector after drying and rolling to obtain a negative electrode sheet;
(2) preparing a positive plate: putting lithium cobaltate, PVDF and superconducting carbon black in N-methyl pyrrolidone according to the mass ratio of 97:2:1 to prepare anode slurry, coating the anode slurry on the front surface and the back surface of an anode current collector (aluminum foil), drying and rolling to form anode active substance layers on the front surface and the back surface of a cathode current collector to obtain an anode sheet;
(3) preparing a lithium ion battery: sequentially stacking the positive plate, the diaphragm and the negative plate, winding to form a battery core, and then carrying out processes such as packaging, battery core baking, liquid injection, hot pressing and the like to obtain the battery (the battery core capacity is about 3 Ah); wherein, the diaphragm is a PP/PE/PP composite film, the thickness of the diaphragm is 9 μm, and the porosity is about 43.43 percent.
In examples 1 to 3 and comparative examples 1 to 5, Dv10, Dv50, Dv99, stonePowder compaction of ink powder PD (g/cm)3)、Dv99-Dv10-1.6Dv50+PD2The Dv99/Dv50 values are shown in Table 1 below.
TABLE 1 physical Properties of negative electrode Material
Figure BDA0003447000670000081
Typically, an electrochemical workstation is used to test the EIS of the cell to evaluate the magnitude of the impedance of the cell. The battery cell impedance tested by the invention is carried out under the condition of 50% SOC, and the battery cell design of the invention is the same except that the negative electrode materials are different, so the EIS can be used for testing the impedance of the feedback negative electrode material. Wherein: r total Rs + Rct + Rsei to reflect the impedance of the anode material. The electrochemical impedance measurement results of the lithium ion batteries of examples 1 to 3 and comparative examples 1 to 5 are shown in table 2 below.
TABLE 2 electrochemical impedance test results
R total (omega) Rs(Ω) Rct(Ω) Rsei(Ω)
Example 1 40.25 12.6 20 7.65
Example 2 40.03 12.8 7.73 19.5
Example 3 41.05 12.5 20.6 7.95
Comparative example 1 43.83 11.9 10.33 21.6
Comparative example 2 43.53 12.8 9.33 21.4
Comparative example 3 38.69 12.1 7.49 19.1
Comparative example 4 37.48 11.6 7.38 18.5
Comparative example 5 37.31 12 7.21 18.1
As can be seen from table 2: when the particle size and the powder compaction of the graphite negative electrode powder meet the following conditions: 1 ≤ Dv99-Dv10-1.6Dv50+ PD2When the impedance is less than or equal to 5.21 and the Dv99/Dv50 is less than or equal to 1.87 and less than or equal to 2.48, a negative electrode material with lower impedance can be obtained, and the energy density of the prepared battery cell is high; when Dv50 is 9.8 μm or less, the powder compaction of the material is low, which results in that the energy density of the battery is too low, and thus the rapid charging performance cannot be obtained under the high energy density condition, and the electrochemical resistance of the negative electrode material obtained in example 3 is superior to that of examples 2 and 1.
Comparative examples 4 and 5 independently reduce the particle size of the material, and can also obtain a negative electrode material with lower resistance; however, compared with example 1, it is unexpectedly found that the powder compaction of the negative electrode material is significantly reduced, and thus the energy density of the prepared battery cell is too low, which does not meet the performance requirement of high rate under the condition of high energy density.
The invention also researches the design of utilizing the negative electrode material to match with different negative electrode plates, wherein the surface density of the positive electrode plate is 12.56g/cm2The 3C/1C cycle performance of the prepared cell design, the rolled thickness, porosity, OI value and capacity retention rate of the lithium ion battery of the negative electrode plate made of the negative electrode material in the above example 1 and comparative example 2 are shown in table 3 below.
TABLE 3 Capacity Retention ratio at 3C/1C 20T for different cell designs using the negative electrode materials of example 1 and comparative example 2
Figure BDA0003447000670000091
Compared with the comparative example 6, the battery cell prepared by using the negative electrode material in the example 1 has higher capacity retention rate under the 3C/1C cycle condition, so that the negative electrode material prepared in the example 1 is easier to realize high-rate charging under the condition of high energy density.
Meanwhile, the invention also researches the influence of the design of the negative pole piece on the performance of the battery cell, and unexpectedly discovers that the porosity of the negative pole piece is reduced along with the improvement of compaction of the negative pole piece, and the capacity retention rate of the battery cell under the condition of 3C/1C cycle performance is reduced.
Meanwhile, the surface density of the negative pole piece also influences the cycle performance of the battery cell under the condition of certain compacted density, and the cycle capacity retention rate of the battery cell is reduced along with the increase of the surface density.
In conclusion, by adopting the negative electrode material and the negative electrode plate designed with low compaction and low surface density, a high-rate battery cell with excellent cycle performance can be obtained.
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 (10)

1. The negative electrode material is characterized by comprising graphite powder, wherein the particle size and the powder compaction of the graphite powder meet the following conditions:
-1≤Dv99-Dv10-1.6Dv50+PD2≤5.21
1.87≤Dv99/Dv50≤2.48
wherein:
dv50 represents the particle size of the graphite powder when the volume accumulation reaches 50% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
dv99 represents the particle size of the graphite powder when the volume accumulation reaches 99% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
dv10 represents the particle size of the graphite powder when the volume accumulation reaches 10% from the small particle size side in the volume-based particle size distribution, and the unit is: mu m;
PD refers to the powder compaction of graphite powder, unit: g/cm3。
2. The negative electrode material of claim 1, wherein the particle size and powder compaction of the graphite powder satisfy the following conditions:
2.7≤Dv99-Dv10-1.6Dv50+PD2≤4.2
2.1≤Dv99/Dv50≤2.35
dv50, Dv99, Dv10 and PD are as defined in claim 1.
3. The negative electrode material of claim 1, wherein the Dv50 of the graphite powder satisfies: dv50 is more than or equal to 12 mu m and less than or equal to 14.6 mu m;
and/or the Dv99 of the graphite powder satisfies: dv99 is more than or equal to 25 mu m and less than or equal to 31 mu m;
and/or the Dv10 of the graphite powder satisfies: dv10 is less than or equal to 7.0 mu m and less than or equal to 9.1 mu m.
4. The negative electrode material according to any one of claims 1 to 3, wherein the PD of the graphite powder is 1.9 to 2.05g/cm3。
5. A negative electrode tab, characterized in that it comprises the negative electrode material of any one of claims 1 to 4.
6. The negative electrode plate of claim 5, wherein the negative electrode material in the negative electrode plate has a mass content of 95.3-98%.
7. The negative electrode tab of claim 5, wherein the porosity of the negative electrode tab is 18.3% to 30%.
8. The negative electrode tab of claim 5, wherein the negative electrode tab has an OI value of 12 to 25.
9. The negative pole piece of claim 5, wherein the single-sided pasting thickness d of the negative pole piece satisfies: 0.9Dv 99. ltoreq. d.ltoreq.5.5 Dv50, Dv99 and Dv50 being as defined in claim 1.
10. A lithium ion battery comprising the negative electrode material of any one of claims 1 to 4, or the negative electrode sheet of any one of claims 5 to 9.
CN202111652704.3A 2021-12-30 2021-12-30 Negative electrode material and negative electrode plate comprising same Pending CN114373927A (en)

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