CN117317129A - Negative electrode plate, preparation method thereof and lithium ion battery - Google Patents

Negative electrode plate, preparation method thereof and lithium ion battery Download PDF

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Publication number
CN117317129A
CN117317129A CN202311202141.7A CN202311202141A CN117317129A CN 117317129 A CN117317129 A CN 117317129A CN 202311202141 A CN202311202141 A CN 202311202141A CN 117317129 A CN117317129 A CN 117317129A
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China
Prior art keywords
negative electrode
thickness
electrode plate
battery
negative
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Pending
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CN202311202141.7A
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Chinese (zh)
Inventor
王健
李洋
朱冠楠
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Shanghai Xuanyi New Energy Development Co ltd
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Shanghai Xuanyi New Energy Development Co ltd
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Priority to CN202311202141.7A priority Critical patent/CN117317129A/en
Publication of CN117317129A publication Critical patent/CN117317129A/en
Pending legal-status Critical Current

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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
    • H01M4/04—Processes of manufacture in general
    • H01M4/043—Processes of manufacture in general involving compressing or compaction
    • H01M4/0435—Rolling or calendering
    • 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
    • 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 invention provides a negative electrode plate, a preparation method thereof and a lithium ion battery. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material coating arranged on the surface of the negative electrode current collector, wherein the negative electrode plate is provided with a first thickness and a second thickness along the unfolding direction, the first thickness is larger than the second thickness, and the length of the negative electrode plate with the first thickness is smaller than that of the negative electrode plate with the second thickness. By applying the technical scheme of the invention, the negative electrode plates have different thicknesses along the unwinding direction, when the negative electrode plates of the type are wound into a winding core to prepare the battery, the full electric expansion at the center of the battery core can be reduced by increasing the thickness of the negative electrode plates at the center, so that the problem of larger stress at the center of the battery core is reduced, the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plates caused by larger stress at the center of the battery core are avoided, the cycle performance of the battery core is improved, and the safety risk of the battery core is reduced.

Description

Negative electrode plate, preparation method thereof and lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a negative electrode plate, a preparation method thereof and a lithium ion battery.
Background
In recent years, in a large sustainable environment, energy strategies face significant changes, new energy automobiles become industries of great importance to society and countries, and lithium ion batteries are also expected to be important components of new energy automobiles in the industry.
In the charging process of the battery, the thickness of the pole piece is bounced to some extent, so that the stress in the battery is continuously increased and cannot be released, and finally the deformation of the battery core and the wrinkling of the pole piece are caused, especially in the later period of circulation, the deformation of the battery core and the wrinkling of the pole piece become more and more serious and even break, so that the circulation performance of the battery is affected.
In order to solve the problems of cell deformation and pole piece wrinkling, the conventional method is to prepare embossing on the positive pole piece so as to provide space for the thickness rebound of the subsequent pole piece, thereby avoiding cell deformation and pole piece wrinkling. However, the existing problems are that the actual improvement effect is not the same due to the influence of the consistency of the supplied materials and the instability of the embossing device, and the phenomena of cell deformation and pole piece wrinkling still occur.
In view of the foregoing, it is necessary to provide a solution to the above-mentioned problems.
Disclosure of Invention
The invention mainly aims to provide a negative electrode plate, a preparation method thereof and a lithium ion battery, so as to solve the problems that in the prior art, the lithium battery is easy to deform an electric core and wrinkle the electrode plate.
In order to achieve the above object, according to one aspect of the present invention, there is provided a negative electrode tab including a negative electrode current collector and a negative electrode active material coating layer provided on a surface of the negative electrode current collector, the negative electrode tab having a first thickness and a second thickness in a developing direction, the first thickness being greater than the second thickness, a length of the negative electrode tab having the first thickness being smaller than a length of the negative electrode tab having the second thickness.
Further, the first thickness is 1.05 times to 1.3 times the second thickness.
Further, a transition part is arranged between the part with the first thickness and the part with the second thickness of the negative electrode plate, and the length of the transition part is 1-100mm.
Further, the length of the negative electrode plate with the first thickness is 0.15% -10% of the length of the negative electrode plate with the second thickness.
Further, the anode active material coating contains any one or more of graphite, hard carbon, silicon oxygen, and lithium titanate.
Further, both surfaces of the negative electrode current collector are provided with a negative electrode active material coating.
Further, one end of the negative electrode tab has a first thickness and the other end has a second thickness, and the portions having the first thickness and the second thickness are continuous.
According to another aspect of the present application, there is provided a method for preparing the negative electrode sheet of any one of the above, the method comprising: step S1, an active substance is arranged on the surface of a negative current collector, and a prefabricated negative plate is obtained; step S2, performing first rolling on the prefabricated negative plate to obtain a plate with a first thickness; and S3, carrying out second rolling on the pole piece with the first thickness, and intermittently carrying out the second rolling to obtain the negative pole piece.
According to another aspect of the application, a lithium ion battery is provided, which comprises a positive electrode piece, a diaphragm and a negative electrode piece, wherein the positive electrode piece, the diaphragm and the negative electrode piece are wound to form a winding core, the negative electrode piece is the negative electrode piece, and a part of the negative electrode piece with a first thickness is located on a core part of the lithium ion battery.
Further, the number of windings of the negative electrode sheet having the first thickness is 1 to 5.
By applying the technical scheme of the invention, the negative electrode plates have different thicknesses along the unwinding direction, when the negative electrode plates of the type are wound into a winding core to prepare the battery, the full electric expansion at the center of the battery core can be reduced by increasing the thickness of the negative electrode plates at the center, so that the problem of larger stress at the center of the battery core is reduced, the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plates caused by larger stress at the center of the battery core are avoided, the cycle performance of the battery core is improved, and the safety risk of the battery core is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
fig. 1 shows a schematic side view of a negative electrode tab in a direction of deployment according to an embodiment of the invention;
FIG. 2 shows a schematic top view of a winding core according to embodiment 1 of the invention;
FIG. 3 shows a schematic top view of a winding core according to comparative example 1 of the present invention;
FIG. 4 shows a schematic top view of a winding core according to embodiment 2 of the invention;
fig. 5 shows a schematic top view of a winding core according to comparative example 2 of the present invention.
Wherein the above figures include the following reference numerals: 10. a negative electrode plate; 20. a positive electrode sheet; 30. a diaphragm.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present invention will be described in detail with reference to examples.
As analyzed in the background art of the present application, there are problems in the prior art that a lithium battery is prone to cell deformation and pole piece wrinkling, and in order to solve the problems, the present application provides a negative pole piece, a preparation method thereof, and a lithium ion battery.
According to an exemplary embodiment of the present application, there is provided a negative electrode tab including a negative electrode current collector and a negative electrode active material coating layer disposed on a surface of the negative electrode current collector, the negative electrode tab having a first thickness and a second thickness in a developing direction, the first thickness being greater than the second thickness, a length of the negative electrode tab having the first thickness being smaller than a length of the negative electrode tab having the second thickness.
The negative electrode plate has different thicknesses along the unfolding direction, when the negative electrode plate of the type is wound into a winding core to prepare the battery, the full electric expansion of the center of the battery core can be reduced by increasing the thickness of the negative electrode plate at the center, so that the problem of larger stress at the center of the battery core is reduced, the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plate caused by larger stress at the center of the battery core are avoided, the cycle performance of the battery core is improved, and the safety risk of the battery core is reduced.
In some embodiments of the present application, the first thickness is the thickness of the thickest part of the pole piece, the second thickness is the thickness of the thinnest part of the pole piece, the first thickness is 1.05 times to 1.3 times of the second thickness, the pole piece with the first thickness and the second thickness is wound into the battery core from the core center to the outer pole piece thickness from the thickness to the thickness, and the effect is obvious for reducing the full electrical expansion of the center of the battery core. Illustratively, the first thickness may be 1.05 times, 1.1 times, 1.15 times, 1.2 times, 1.25 times, 1.3 times, or a range between any two of the second thicknesses.
In some embodiments of the present application, the negative electrode sheet has the same areal density at different thicknesses, that is, in the areas with different thicknesses, the mass of the negative electrode sheet per unit area is the same, accordingly, due to the different thicknesses of the electrode sheets, the compacted density of the portion with the first thickness is smaller than the compacted density of the portion with the second thickness, when the thickness of the electrode sheet is wound from the center of the winding core to the outside from the thickness of the electrode sheet to the thickness of the electrode sheet, the compacted density of the negative electrode sheet at the center is small, the porosity of the electrode sheet is larger, the electrode sheet stores more electrolyte, thereby being beneficial to lithium ion diffusion in the later period of circulation, the circulation performance of the electrode sheet can be further improved, and the safety risk of the electrode sheet is reduced.
In some typical embodiments of the present application, in order to further improve the performance of the above-mentioned negative electrode tab, the length of the negative electrode tab having the first thickness is 0.15% -10% of the length of the negative electrode tab having the second thickness, and the negative electrode tab having the first thickness is too short to have an effect of reducing the full electrical expansion at the center of the cell, and too long to have a significant effect of reducing the stress at the center of the cell. Typically, but not by way of limitation, the length of the negative electrode sheet having the first thickness is any value in the range of 0.15%, 0.35%, 0.55%, 0.75%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any two of the length of the negative electrode sheet having the second thickness.
In some embodiments of the present application, a transition portion is provided between the portion having the first thickness and the portion having the second thickness of the negative electrode sheet, where the transition portion is a gradient change of the thickness of the negative electrode sheet occurring during actual manufacturing due to adjustment of the rolling device, and has a length of 1-100mm.
In some embodiments of the present application, a schematic side view of a negative electrode sheet along a spreading direction is shown in fig. 1, and the thickness of the negative electrode sheet is intermittently distributed in two sections along the spreading direction, where the thickness of a thicker portion is a first thickness, the thickness of a thinner portion is a second thickness, a thickness near a thickest negative electrode sheet may have an obvious gradient, that is, the above-mentioned transition portion, when the negative electrode sheet shown in fig. 1 is used to prepare a battery, the negative electrode sheet needs to be sectioned, one end of each obtained negative electrode sheet is the first thickness, and when the battery is prepared by winding, the end is located in a core, the other end is the second thickness, and each electrode sheet has only one gradient change portion.
The specific materials of the negative electrode plate for the negative electrode current collector and the negative electrode active material coating are not particularly required, and the negative electrode plate is selected from the prior art. In some embodiments of the present application, the negative electrode active material coating contains any one or more of graphite, hard carbon, silicon oxygen, and lithium titanate.
The negative electrode plate can be provided with a negative electrode active material coating on one surface of the negative electrode current collector, and can be provided with the negative electrode active material coating on both surfaces. In order to better exert the reduction effect of the full-charge expansion of the pole pieces with different thicknesses on the center of the battery cell, the two surfaces of the negative pole piece show thickness variation, and preferably, the two surfaces of the negative pole current collector are provided with negative pole active material coatings.
In some embodiments of the present application, one end of the negative electrode piece has a first thickness, which is the thickest part of the negative electrode piece, the other end has a second thickness, which is the thinnest part of the negative electrode piece, and the parts with the first thickness and the second thickness are continuous, and the negative electrode piece can be obtained by cutting the negative electrode piece with intermittent two-section distribution, and can be wound into an electrical core from the thickness of the core to the thickness of the external electrode piece from the thickness to the thickness.
According to another exemplary embodiment of the present application, there is provided a method for preparing a negative electrode sheet according to any one of the above, the method comprising: step S1, an active substance is arranged on the surface of a negative current collector, and a prefabricated negative plate is obtained; step S2, performing first rolling on the prefabricated negative plate to obtain a plate with a first thickness; and S3, carrying out second rolling on the pole piece with the first thickness, and intermittently carrying out the second rolling to obtain the negative pole piece.
When the negative electrode plate prepared by the method is wound into a winding core to prepare a battery, the thickness of the negative electrode plate at the center can be increased to reduce the full electrical expansion at the center of the battery core, so that the problem of larger stress at the center of the battery core is reduced, and the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plate caused by larger stress at the center of the battery core are avoided. On the other hand, the preparation method enables the negative electrode plate at the center to be compacted to be smaller so as to increase the porosity of the electrode plate, and the electrode plate can store more electrolyte so as to be beneficial to the diffusion of lithium ions in the later period of circulation. Therefore, the negative electrode plate prepared by the method can improve the cycle performance of the battery cell and effectively reduce the safety risk of the battery cell.
According to yet another exemplary embodiment of the present application, there is provided a lithium ion battery, including a positive electrode sheet, a separator, and a negative electrode sheet, the positive electrode sheet, the separator, and the negative electrode sheet are wound to form a winding core, wherein the negative electrode sheet is the negative electrode sheet described above, and a portion of the negative electrode sheet having a first thickness is located in a core of the lithium ion battery.
The lithium ion battery has the advantages that the thickness of the negative plate at the center of the lithium ion battery is larger, the full electric expansion at the center of the battery cell is reduced, so that the problem of larger stress at the center of the battery cell is reduced, and the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plate caused by larger stress at the center of the battery cell are avoided. On the other hand, the compaction of the negative electrode plate at the center of the battery becomes smaller, so that the porosity of the electrode plate is increased, and the electrode plate can store more electrolyte, so that the diffusion of lithium ions in the later period of circulation is facilitated. Therefore, the lithium ion battery is put into the battery, and the negative electrode plate is used, so that the cycle performance of the battery cell is improved, and the safety risk of the battery cell is effectively reduced.
The positive electrode sheet and the separator are not particularly required, and may be selected from the prior art, and will not be described in detail herein.
In some embodiments of the present application, in order to further improve the battery cell cycle performance of the lithium battery, the winding number of the negative electrode sheet having the first thickness is 1 to 10, preferably 1 to 5.
As an example, the preparation method of the lithium ion battery is as follows: and sequentially superposing the negative electrode plate, the diaphragm and the positive electrode plate, jointly winding the negative electrode plate, the diaphragm and the positive electrode plate into a winding core, and assembling the winding core to form the battery, wherein the negative electrode plate with different thicknesses of the positive electrode plate is wound from the center of the winding core to the thickness of the external electrode plate from thick to thin.
The advantages that can be achieved by the present application will be further described below in connection with examples and comparative examples. The operations referred to in the examples, unless otherwise specified, are all conventional in the art.
The negative electrode current collector of the negative electrode plate of the embodiment and the comparative example is copper foil with the thickness of 6 mu m, and the main component of the negative electrode active material coating is graphite; the diaphragm is a single-sided ceramic diaphragm, and the positive pole piece is ternary.
Example 1
As shown in fig. 2, this embodiment provides a negative electrode tab 10, both sides of a current collector are provided with active material coatings, a first thickness of 140 μm, a tab length of 15mm having the thickness, a second thickness of 130 μm, a tab length of 5500mm having the thickness, and a length of a transition portion between the first thickness and the second thickness of 2mm.
The negative pole piece is wound into a cylindrical winding core, the thickness of the two turns of negative pole pieces at the innermost side of the winding core is 140 mu m, and the thickness of the negative pole pieces at the middle and the outer sides of the winding core is 130 mu m. The top view of the wound core after winding the negative electrode sheet 10, the positive electrode sheet 20 and the separator 30 is shown in fig. 2 (in the figure, the dark and thick part of the negative electrode sheet 10 inside the wound core is a first thickness, the rest part is a second thickness, and the transition part is not represented). And assembling the wound winding core to prepare the battery.
Comparative example 1
This comparative example provides a negative electrode sheet 10, the thickness of the negative electrode sheet 10 was 130 μm, the total length was the same as the negative electrode sheet 10 of example 1, and the negative electrode sheet 10 was wound with the same positive electrode sheet 20 and separator 30 as in example 1 to form a winding core, which is shown in fig. 3.
Example 2
As shown in fig. 4, this embodiment provides a negative electrode tab 10, both sides of a current collector are provided with active material coatings, a first thickness of 140 μm, a tab length of 33mm having the thickness, a second thickness of 130 μm, a tab length of 5480mm having the thickness, and a transition portion of 2mm between the first thickness and the second thickness.
The pole piece is wound into a flat winding core, the thickness of the pole piece of the innermost 2 circles of the winding core is 140 mu m, the thickness of the pole piece at the middle and the outer sides of the winding core is 130 mu m, the winding core after the negative pole piece 10, the positive pole piece 20 and the diaphragm 30 are wound is shown in fig. 4 (in the drawing, the deep and thick part of the negative pole piece 10 in the winding core is a first thickness, the rest part is a second thickness, and the transition part is not embodied). And assembling the wound winding core to prepare the battery.
Comparative example 2
This comparative example provides a negative electrode sheet 10, the thickness of the negative electrode sheet 10 was 130 μm, the total length was the same as the negative electrode sheet 10 of example 2, and the negative electrode sheet 10 was wound with the same positive electrode sheet 20 and separator 30 as in example 2 to form a winding core, which is shown in fig. 5.
Example 3
The difference from example 1 was only that the first thickness of the negative electrode tab of this example was 165 μm and the length of the transition portion between the first thickness and the second thickness was 5mm. The thickness of the two innermost turns of the negative electrode sheet of the winding core was 165 μm, and the winding was the same as in example 1.
Example 4
The difference from example 1 was only that the first thickness of the negative electrode tab of this example was 180 μm and the length of the transition portion between the first thickness and the second thickness was 30mm. The thickness of the two innermost turns of the negative electrode sheet of the winding core is 180 μm, and the winding mode is the same as that of the embodiment 1.
Example 5
The difference from example 1 is only that the length of the pole piece with the first thickness is 500mm, the length of the pole piece with the second thickness is 5000mm, the thickness of the negative pole piece on the inner side of the winding core is 17 turns of the pole piece with the first thickness.
Example 6
The difference from example 1 was only that the length of the pole piece having the first thickness was 230mm, the length of the pole piece having the second thickness was 5270mm, and the thickness of the negative pole piece inside the winding core was 10 turns of the pole piece having the first thickness.
Example 7
The difference from example 1 was only that the length of the pole piece having the first thickness was 15mm, the length of the pole piece having the second thickness was 5485mm, and the thickness of the negative pole piece inside the winding core was 1 turn of the pole piece having the first thickness.
Example 8
The difference from example 1 was only that the length of the pole piece having the first thickness was 100mm, the length of the pole piece having the second thickness was 5400mm, and the thickness of the negative pole piece inside the winding core was 5 turns of the pole piece having the first thickness.
The batteries prepared in the above examples and comparative examples were tested as follows:
cell deformation condition: the battery cell is disassembled after the battery cell is circularly attenuated to 80%, and the deformation condition of the battery cell is confirmed;
pole piece wrinkling condition: dismantling the battery core after the battery core is circularly attenuated to 80%, and confirming the wrinkling condition of the pole piece at the inner ring of the battery core;
cycle number: the cell cycle decays to 80% of the turns.
The test results of the prepared batteries of the above examples and comparative examples are shown in table 1 below.
TABLE 1
Battery cell Cell deformation condition Pole piece wrinkling condition Cycle number @80%
Example 1 No deformation No wrinkling 2346
Comparative example 1 Severe deformation Severe wrinkling 1714
Example 2 No deformation No wrinkling 2277
Comparative example 2 Severe deformation Severe wrinkling 1889
Example 3 No deformation No wrinkling 2016
Example 4 No deformation No wrinkling 1858
Example 5 No deformation No wrinkling 2058
Example 6 No deformation No wrinkling 2167
Example 7 Deformation of Wrinkling 1917
Example 8 No deformation No wrinkling 2389
From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: the negative electrode plate has different thicknesses along the unfolding direction, when the negative electrode plate of the type is wound into a winding core to prepare the battery, the full electric expansion of the center of the battery core can be reduced by increasing the thickness of the negative electrode plate at the center, so that the problem of larger stress at the center of the battery core is reduced, the problems of lithium precipitation, wrinkling, material dropping and the like of the electrode plate caused by larger stress at the center of the battery core are avoided, the cycle performance of the battery core is improved, and the safety risk of the battery core is reduced.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. 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 plate comprises a negative electrode current collector and a negative electrode active material coating arranged on the surface of the negative electrode current collector, and is characterized in that the negative electrode plate is provided with a first thickness and a second thickness along the unfolding direction, the first thickness is larger than the second thickness, and the length of the negative electrode plate with the first thickness is smaller than that of the negative electrode plate with the second thickness.
2. The negative electrode tab of claim 1, wherein the first thickness is 1.05-1.3 times the second thickness.
3. The negative electrode tab of claim 1, wherein the portion of the negative electrode tab having the first thickness and the portion having the second thickness have a transition portion therebetween, the transition portion having a length of 1-100mm.
4. The negative electrode tab of claim 1, wherein the length of the negative electrode tab having the first thickness is 0.15% to 10% of the length of the negative electrode tab having the second thickness.
5. The negative electrode sheet according to claim 1, wherein the negative electrode active material coating contains any one or more of graphite, hard carbon, silicon oxygen, and lithium titanate.
6. The negative electrode tab according to claim 1, wherein both surfaces of the negative electrode current collector are provided with the negative electrode active material coating.
7. The negative electrode tab of any one of claims 1-6, wherein one end of the negative electrode tab has a first thickness and the other end has the second thickness, and the portions having the first thickness and the second thickness are continuous.
8. The method for producing a negative electrode sheet according to any one of claims 1 to 7, comprising:
step S1, an active substance is arranged on the surface of a negative current collector, and a prefabricated negative plate is obtained;
s2, performing first rolling on the prefabricated negative plate to obtain a plate with a first thickness;
and step S3, performing second rolling on the pole piece with the first thickness, wherein the second rolling is performed intermittently, and the negative pole piece is obtained.
9. A lithium ion battery, comprising a positive electrode plate, a diaphragm and a negative electrode plate, wherein the positive electrode plate, the diaphragm and the negative electrode plate are wound to form a winding core, the negative electrode plate is the negative electrode plate of claim 7, and the part of the negative electrode plate with the first thickness is positioned at the core of the lithium ion battery.
10. The lithium ion battery of claim 9, wherein the number of windings of the negative electrode tab having the first thickness is 1-5.
CN202311202141.7A 2023-09-15 2023-09-15 Negative electrode plate, preparation method thereof and lithium ion battery Pending CN117317129A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311202141.7A CN117317129A (en) 2023-09-15 2023-09-15 Negative electrode plate, preparation method thereof and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311202141.7A CN117317129A (en) 2023-09-15 2023-09-15 Negative electrode plate, preparation method thereof and lithium ion battery

Publications (1)

Publication Number Publication Date
CN117317129A true CN117317129A (en) 2023-12-29

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Country Status (1)

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