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CN-120453291-B - Negative plate, preparation method, battery and electric equipment

CN120453291BCN 120453291 BCN120453291 BCN 120453291BCN-120453291-B

Abstract

The invention relates to the technical field of lithium batteries, in particular to a negative electrode plate, a preparation method, a battery and electric equipment. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one side surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, the negative electrode active material comprises a carbon-based material, the OI value of the negative electrode active material layer meets 0< OI <30, a groove is formed in the surface, far away from the negative electrode current collector, of the negative electrode active material layer, and the orientation degree OI value is the intensity ratio of a (004) diffraction peak to a (110) diffraction peak of the negative electrode active material layer in an XRD diffraction pattern. The negative electrode sheet thus has a faster charge rate and also has a longer fast charge cycle life.

Inventors

  • HE JUNWU
  • HE KEFENG
  • YUAN XIAOTAO
  • PAN ZHIHAO
  • LEI YU

Assignees

  • 比亚迪股份有限公司
  • 深圳市比亚迪锂电池有限公司

Dates

Publication Date
20260505
Application Date
20240925

Claims (13)

  1. 1. A negative electrode sheet characterized by comprising a negative electrode current collector and a negative electrode active material layer provided on at least one side surface of the negative electrode current collector; the negative electrode active material layer comprises a negative electrode active material comprising a carbon-based material, and the degree of orientation OI value of the negative electrode active material layer satisfies 0< OI <30; a groove is formed in the surface, far away from the negative electrode current collector, of the negative electrode active material layer; wherein the orientation degree OI value is the intensity ratio of a (004) diffraction peak to a (110) diffraction peak of the anode active material layer in an XRD diffraction pattern, The depth d of the groove, the compaction density V of the negative electrode plate and the OI value of the negative electrode active material layer are 0.5V multiplied by OI, d is less than or equal to 100 The depth d of the groove is in mu m, and the compaction density V of the negative plate is in g/cm 3 .
  2. 2. The negative electrode sheet according to claim 1, wherein the negative electrode active material layer has an OI value of 0.1≤OI≤5.
  3. 3. The negative plate according to claim 1, wherein the depth of the groove is 10 μm to 70 μm; And/or the width of the groove is 20-150 μm.
  4. 4. The negative plate of claim 1, wherein the negative plate has a compacted density of 1.2g/cm 3 -1.9g/cm 3 .
  5. 5. The negative plate of claim 1, wherein the negative plate has a compacted density of 1.5g/cm 3 -1.7g/cm 3 .
  6. 6. The negative electrode tab of claim 1, wherein the grooves include a plurality of first grooves extending in a length direction of the negative electrode current collector and a plurality of second grooves extending in a width direction of the negative electrode current collector, the first grooves intersecting the second grooves; the distance between the adjacent second grooves is g1, the distance between the adjacent first grooves is g2, and the g1 and the g2 are 0.1-50.
  7. 7. The negative electrode sheet according to claim 6, wherein g1 is 100 μm to 5000 μm and g2 is 100 μm to 1000 μm.
  8. 8. The negative plate of claim 1, wherein the negative plate has an areal density of 150g/m 2 -500g/m 2 .
  9. 9. The negative plate of claim 1, wherein the negative plate has an areal density of 200g/m 2 -300g/m 2 .
  10. 10. The negative electrode sheet according to claim 1, wherein the tortuosity of the negative electrode active material layer is 2.2 to 3.5.
  11. 11. A method for producing the negative electrode sheet according to any one of claims 1 to 10, comprising: Preparing negative electrode active slurry, wherein the negative electrode active slurry comprises a carbon-based material, and the negative electrode active slurry is coated on at least one side surface of a negative electrode current collector; Treating the negative electrode active slurry through a magnetic induction orientation device, drying and rolling to obtain a negative electrode active material layer; and grooving the surface of the negative electrode active material layer far away from the negative electrode current collector to obtain the negative electrode plate.
  12. 12. A battery comprising the negative electrode sheet according to any one of claims 1 to 10.
  13. 13. A powered device comprising the battery of claim 12.

Description

Negative plate, preparation method, battery and electric equipment Technical Field The invention relates to the technical field of lithium batteries, in particular to a negative plate, a preparation method, a battery and electric equipment. Background With the rapid development and the increasing competition of the new energy automobile industry, the performance of the power battery is required to be higher, namely, higher energy density and shorter charging time are required. For the performance requirement of high energy density, the mode of improving the electrode surface density and compaction is generally adopted at present, along with the increase of the surface density and the compaction degree, the number of layers of the electrode plate can be reduced for the same capacity design, and then the proportion of non-active substances such as current collectors, diaphragms and the like is reduced, so that the improvement of the energy density is realized, and for the performance requirement of shorter charging time, the mode of reducing the electrode surface density and the compaction is generally adopted, along with the reduction of the surface density and the compaction degree, the thickness of the electrode plate is reduced, the pores are increased, and the lithium ion transmission capacity is enhanced, so that the quick charging is realized. The method is characterized in that the method comprises the steps of increasing the surface density and the compactness of an electrode, realizing the performance requirement of high energy density, reducing the surface density and the compactness of the electrode, and realizing quick charge, however, the two methods are contradictory, and cannot simultaneously realize high energy density and shorter charge time, because as the surface density and the compactness are increased, the thickness of the electrode is increased, so that the transmission path of lithium ions is prolonged, the compactness is increased, pores are reduced, graphite particles of the negative electrode are more prone to be arranged parallel to the direction of a current collector under high compaction, the tortuosity of an ion path formed from the surface of the electrode to the bottom of the electrode by pores among electrode material particles is increased, the transmission path of lithium ions is prolonged, the transmission rate of lithium ions is reduced, and larger polarization internal resistance is generated in the process of high-current charge, so that poor quick charge performance is caused. Meanwhile, the high compactness can also lead to the compactness of the electrode surface layer, the infiltration capacity of electrolyte to the electrode is poor, and the quick charge cycle life is shortened. It is therefore desirable to provide an electrode that can achieve high energy density and shorter charging times. Disclosure of Invention The present invention aims to solve one of the technical problems in the related art at least to some extent. Therefore, the invention provides a negative plate, a preparation method, a battery and electric equipment. The negative electrode sheet has a faster charge rate and also has a longer fast charge cycle life. To this end, a first aspect of the present invention provides a negative electrode sheet including a negative electrode current collector and a negative electrode active material layer provided on at least one side surface of the negative electrode current collector; The anode active material layer comprises an anode active material comprising a carbon-based material, and the OI value of the anode active material layer satisfies 0< OI <30; a groove is formed in the surface, far away from the negative electrode current collector, of the negative electrode active material layer; Wherein the orientation degree OI value is an intensity ratio of a (004) diffraction peak to a (110) diffraction peak of the anode active material layer in an XRD diffraction pattern. According to the invention, when the orientation degree OI value of the anode active material layer is 0< OI <30, carbon-based material particles in the electrode are more prone to be arranged perpendicular to the direction of the current collector, the bending degree of pore structures formed among the particles is reduced, the bending degree of ion paths formed by pores among the electrode material particles from the surface of the electrode to the bottom of the electrode is greatly reduced, the transmission path of lithium ions is shortened, the diffusion capacity of the lithium ions is enhanced, the polarization internal resistance in the high-current charging process is reduced, and the quick charging performance is improved. Meanwhile, the grooves arranged on the surface of the pole piece can generate capillary action, so that the infiltration capacity of electrolyte to the electrode can be greatly improved, a certain liquid storage effect is achieved, the phenomenon that the circu