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CN-122025737-A - Battery cell

CN122025737ACN 122025737 ACN122025737 ACN 122025737ACN-122025737-A

Abstract

The application belongs to the technical field of new energy batteries, and particularly relates to a battery. The application provides a battery, which comprises a positive plate, a negative plate and electrolyte, wherein the negative plate comprises a negative current collector and a negative active layer arranged on at least one side surface of the negative current collector, the negative active layer comprises a silicon-based material, the sphericity a of the silicon-based material is more than or equal to 0.85 and less than or equal to 0.99, the electrolyte comprises a compound B and propylene carbonate, the mass content of the compound B in the electrolyte is B percent, the mass content of the compound B is more than or equal to 0.01 and less than or equal to 5, and the mass content of the compound B is more than or equal to 0.2 and less than or equal to 15. The compound B can replace part of propylene carbonate to enter a solvated shell layer, so that the lithium ion deintercalation efficiency is improved, the risk of falling off of a silicon-based material with poor adhesive force caused by embedding the propylene carbonate into a negative electrode is reduced, and meanwhile, the compound B can also generate an interfacial film with high elasticity, high strength and low impedance, thereby being beneficial to the high-temperature cycle and low-temperature cycle performance of a battery.

Inventors

  • Xiang Hanqing
  • QIU YAMING

Assignees

  • 珠海冠宇电池股份有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. A battery comprises a positive plate, a negative plate and electrolyte, wherein the negative plate comprises a negative current collector and a negative active layer arranged on at least one side surface of the negative current collector, The anode active layer comprises a silicon-based material, and the sphericity a of the silicon-based material is more than or equal to 0.85 and less than or equal to 0.99; The electrolyte comprises a compound B and propylene carbonate, wherein the mass content of the compound B is recorded as B% based on the mass of the electrolyte, and the mass content of the compound B is more than or equal to 0.01 and less than or equal to 5; I is a kind of Wherein n=0 or 1;R 1 、R 2 is independently selected from any one of H, halogen substituted or unsubstituted alkyl with 1-6 carbon atoms, halogen substituted or unsubstituted alkenyl with 2-6 carbon atoms, halogen substituted or unsubstituted alkynyl with 2-6 carbon atoms, and R 1 、R 2 cannot be H at the same time; and satisfies a/b of 0.2-15.
  2. 2. The battery according to claim 1, wherein the compound B has any one of the following structures: ; and/or b is more than or equal to 0.1 and less than or equal to 4; And/or 0.25≤a/b≤10.
  3. 3. The battery according to claim 1 or 2, wherein the anode active layer includes a first active layer and a second active layer that are stacked, the first active layer being located between the anode current collector and the second active layer; the mass content of the silicon element of the first active layer is denoted as H1%, the mass content of the silicon element of the second active layer is denoted as H2%, and H1 is smaller than H2.
  4. 4. The battery of claim 3, wherein the first active layer has a thickness of 10 μιη -65 μιη; And/or the thickness of the second active layer is 10 μm to 65 μm; and/or, H2 is more than or equal to 2 and less than or equal to 50; and/or, 0≤H2≤30.
  5. 5. The battery according to claim 1 or 2, characterized in that at least one of the following conditions is also satisfied: (1) The electrolyte further includes a compound E including at least one of vinyl sulfate, methylene methane disulfonate, 1, 3-propane sultone, vinyl sulfite, propylene sulfite, vinyl disulfate, trimethylsilyl methane sulfonate, dimethyl methylene sulfonate, 4-acetylphenyl trifluoro methane sulfonate, phenyl trifluoro methane sulfonate, 6-quinolyl trifluoro methane sulfonate, 1, 3-propene sultone, 1, 4-butane sultone, mannitol carbonate sulfate, and formulas (II-1) to (II-3); ; (2) The electrolyte also comprises a compound F, wherein the compound F comprises at least one of lithium difluorophosphate, lithium difluorooxalato phosphate, lithium tetrafluorooxalato phosphate, lithium bisoxalato phosphate, lithium tetrafluoroborate, lithium difluorooxalato borate and lithium difluorooxalato borate; (3) The electrolyte also includes propyl propionate.
  6. 6. The cell according to claim 5, wherein the mass content of the compound E is e%, based on the total mass of the electrolyte, such that 0.1≤e≤10, preferably 0.5≤e≤6; And/or, based on the total mass of the electrolyte, the mass content of the compound F is F, and F is more than or equal to 0.01 and less than or equal to 3; and/or, based on the total mass of the electrolyte, the mass content of the propyl propionate is g, and the g is more than or equal to 5 and less than or equal to 40; And/or, based on the total mass of the electrolyte, the mass content of the propylene carbonate is i, and the i is more than or equal to 5 and less than or equal to 30.
  7. 7. The battery of claim 6, wherein 0.01≤b/e≤20 is satisfied.
  8. 8. The cell of claim 1 or 2, wherein the silicon-based material comprises a silicon-carbon material comprising a porous carbon substrate and silicon particles dispersed within pores of the porous carbon substrate.
  9. 9. The battery according to claim 1 or 2, wherein at least part of the outer surface of the silicon-based material is provided with a coating layer.
  10. 10. The battery of claim 9, wherein the coating has a thickness of 0.5nm to 35nm, and/or the coating comprises at least one of amorphous carbon, alumina, meta-aluminate, graphitized carbon, and silica; Preferably, the graphitized carbon comprises carbon nanotubes, the tube diameter of the carbon nanotubes is 1nm-40nm, and preferably, the length of the carbon nanotubes is 0.1 mu m-30 mu m.

Description

Battery cell Technical Field The application belongs to the technical field of new energy batteries, and particularly relates to a battery. Background With the rapid development of new energy automobiles, energy storage systems and high-end consumer electronics, the market has put higher and higher demands on the energy density of lithium ion batteries. Under the background, the silicon-based anode material becomes one of key technical directions for breaking through the bottleneck of the current energy density due to the extremely high theoretical specific capacity, and is gradually popularized in industrial application. Although the silicon-doped anode has been significantly developed in the aspects of material modification, structural design, electrolyte matching and the like under the condition of normal temperature (20-25 ℃), the application of the silicon-doped anode in a wider temperature range still faces serious challenges, namely the internal resistance is increased, polarization is serious in a low-temperature environment, the capacity is attenuated and lithium is further separated seriously due to the reduction of the circulation stability, and the side reaction in the battery is accelerated at high temperature in a high-temperature environment, the circulation stability is influenced, and the irreversible capacity loss is caused. Disclosure of Invention Therefore, the technical problem to be solved by the application is to overcome the defect of poor cycling stability of the battery in a wide temperature range in the prior art, thereby providing a battery. For this purpose, the application provides the following technical scheme. In a first aspect, the present application provides a battery comprising a positive electrode sheet, a negative electrode sheet, and an electrolyte, the negative electrode sheet comprising a negative electrode current collector and a negative electrode active layer disposed on at least one side surface of the negative electrode current collector, The anode active layer comprises a silicon-based material, and the sphericity a of the silicon-based material is more than or equal to 0.85 and less than or equal to 0.99; The electrolyte comprises a compound B and propylene carbonate, wherein the mass content of the compound B is recorded as B% based on the mass of the electrolyte, and the mass content of the compound B is more than or equal to 0.01 and less than or equal to 5; I is a kind of Wherein n=0 or 1;R 1、R2 is independently selected from any one of H, halogen substituted or unsubstituted alkyl with 1-6 carbon atoms, halogen substituted or unsubstituted alkenyl with 2-6 carbon atoms, halogen substituted or unsubstituted alkynyl with 2-6 carbon atoms, and R 1、R2 cannot be H at the same time; and satisfies a/b of 0.2-15. In some embodiments, the compound B has a structure as shown in any one of: 。 in some embodiments, 0.1≤b≤4. In some embodiments, 0.25≤a/b≤10. In some embodiments, the anode active layer includes a first active layer and a second active layer disposed in a stack, the first active layer being located between the anode current collector and the second active layer; the mass content of the silicon element of the first active layer is denoted as H1%, the mass content of the silicon element of the second active layer is denoted as H2%, and H1 is smaller than H2. In some embodiments, the first active layer has a thickness of 10 μm to 65 μm. In some embodiments, the second active layer has a thickness of 10 μm to 65 μm. In some embodiments of the present invention, in some embodiments, H2 is more than or equal to 2 and less than or equal to 50. In some embodiments of the present invention, in some embodiments, H1 is more than or equal to 0 and less than or equal to 30. In some embodiments, at least one of the following conditions is also satisfied: (1) The electrolyte further includes a compound E including at least one of vinyl sulfate, methylene methane disulfonate, 1, 3-propane sultone, vinyl sulfite, propylene sulfite, vinyl disulfate, trimethylsilyl methane sulfonate, dimethyl methylene sulfonate, 4-acetylphenyl trifluoro methane sulfonate, phenyl trifluoro methane sulfonate, 6-quinolyl trifluoro methane sulfonate, 1, 3-propene sultone, 1, 4-butane sultone, mannitol carbonate sulfate, and formulas (II-1) to (II-3); ; (2) The electrolyte also comprises a compound F, wherein the compound F comprises at least one of lithium difluorophosphate, lithium difluorooxalato phosphate, lithium tetrafluorooxalato phosphate, lithium bisoxalato phosphate, lithium tetrafluoroborate, lithium difluorooxalato borate and lithium difluorooxalato borate; (3) The electrolyte also includes propyl propionate. In some embodiments, the mass content of the compound E is e≤e≤10, based on the total mass of the electrolyte, and further, in some embodiments, 0.5≤e≤6. In some embodiments, the mass content of the compound F is F, based on the total mass of the electrolyte, satisfying 0.01≤