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EP-4738515-A1 - LITHIUM-ION SECONDARY BATTERY AND ELECTRIC APPARATUS

EP4738515A1EP 4738515 A1EP4738515 A1EP 4738515A1EP-4738515-A1

Abstract

Provided herein is a lithium-ion secondary battery and an electrical apparatus. In this disclosure, parameters related to an anode and an electrolyte of the lithium-ion secondary battery are reasonably designed, such that the lithium-ion secondary battery satisfies a relationship: 6.7 ≤ CB × PD / (η × A) ≤ 160, where CB represents a capacity excess coefficient of the lithium-ion secondary battery; A represents a mass percentage of the DTD in the electrolyte; PD represents a compaction density of the anode active material layer; η represents a viscosity of the electrolyte.

Inventors

  • LV, Guoxian
  • QIAO, Feiyan

Assignees

  • Sunwoda Mobility Energy Technology Co., Ltd.

Dates

Publication Date
20260506
Application Date
20231226

Claims (12)

  1. A lithium-ion secondary battery, comprising a cathode, an anode, an electrolyte, and a separator, wherein the anode comprises an anode current collector and an anode active material layer arranged on at least one surface of the anode current collector; the electrolyte comprises an organic solvent, a lithium salt, and an additive; the additive comprises DTD; the lithium-ion secondary battery satisfies a relationship as follows: 6.7 ≤ CB × PD / η × A ≤ 160 , wherein CB represents a capacity excess coefficient of the lithium-ion secondary battery, which is a ratio of an anode capacity to a cathode capacity under the same area; A represents a mass percentage of the DTD in the electrolyte; PD represents a compaction density of the anode active material layer in g/cm 3 ; and η represents a viscosity of the electrolyte at 25°C in mPa·s.
  2. The lithium-ion secondary battery according to claim 1, wherein the lithium-ion secondary battery satisfies a relationship as follows: 14 ≤ CB × PD/(η × A) ≤ 62.
  3. The lithium-ion secondary battery according to claim 1, wherein the CB is 1 to 1.6.
  4. The lithium-ion secondary battery according to claim 1, wherein the A is 0.5% to 3%.
  5. The lithium-ion secondary battery according to claim 1, wherein the PD is 1 g/cm 3 to 2 g/cm 3 .
  6. The lithium-ion secondary battery according to claim 1, wherein the η is 2 mPa·s to 5 mPa·s.
  7. The lithium-ion secondary battery according to any one of claims 1 to 6, wherein an anode active material in the anode active material layer satisfies one or more of the followings: (1) the anode active material comprises at least one of graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, or lithium titanate; (2) D V50 of the anode active material is 5 µm to 30 µm, and D V50 is a particle size at which a cumulative volume distribution percentage of the anode active material reaches 50%; (3) an oil absorption value of the anode active material is 10 mL/100g to 100 mL/100g.
  8. The lithium-ion secondary battery according to any one of claims 1 to 6, wherein a total mass m of the electrolyte in the lithium-ion secondary battery and a rated capacity cap of the lithium-ion secondary battery satisfy: m/cap = 1.5 g/Ah to 5 g/Ah.
  9. The lithium-ion secondary battery according to any one of claims 1 to 6, wherein the electrolyte satisfies one or more of the followings: (1) the organic solvent comprises at least one of cyclic carbonate, linear carbonate, or carboxylic ester; (2) the lithium salt comprises at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluoroborate, or lithium tetrafluoro(oxalato)borate; (3) the additive further comprises at least one of vinylene carbonate, 1,3-propanesultone, fluoroethylene carbonate, tris(trimethylsilyl) phosphate, or lithium difluorophosphate.
  10. The lithium-ion secondary battery according to claim 9, wherein the additive further comprises tris(trimethylsilyl) phosphate.
  11. The lithium-ion secondary battery according to any one of claims 1 to 6, wherein a cathode active material in the cathode comprises at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium nickel manganese oxide, lithium cobalt oxide, lithium-rich manganese-based solid solution, or lithium manganese oxide.
  12. An electrical apparatus, comprising the lithium-ion secondary battery according to any one of claims 1 to 11.

Description

CROSS-REFERENCE TO RELATED APPLICATION This disclosure claims the benefit of Chinese patent application No. 202310791633.8, filed on June 29, 2023, which is incorporated herein by reference in its entirety. TECHNICAL FIELD This disclosure relates to the field of battery technology, particularly to a lithium-ion secondary battery and an electrical apparatus. BACKGROUND Lithium-ion secondary batteries have outstanding characteristics such as high specific energy, long lifespan, environmental friendliness, and no memory effect, and are widely used in portable electronic apparatus and new energy vehicles. However, the widespread adoption of new energy vehicles has been limited by their driving range. One approach to increase the driving range is to reduce the charging time of the batteries. Therefore, providing a lithium-ion secondary battery with excellent fast-charging performance is a problem that needs to be solved. SUMMARY An objective of this disclosure is to provide a lithium-ion secondary battery with excellent fast-charging performance. In this disclosure, parameters related to an anode and an electrolyte of the lithium-ion secondary battery are reasonably designed, to significantly improve the fast-charging performance and cycle performance of the lithium-ion secondary battery. To achieve the above objective, in a first aspect, provided herein is a lithium-ion secondary battery, comprising a cathode, an anode, an electrolyte, and a separator, wherein the anode comprises an anode current collector and an anode active material layer arranged on at least one surface of the anode current collector; the electrolyte comprises an organic solvent, a lithium salt, and an additive; the additive comprises 1,3,2-dioxathiolane-2,2-dioxide (DTD); the lithium-ion secondary battery satisfies a relationship as follows: 6.7≤CB×PD/η×A≤160, wherein CB represents a capacity excess coefficient of the lithium-ion secondary battery, which is a ratio of an anode capacity to a cathode capacity under the same area (i.e., negative-to-positive capacity ratio per unit area, also referred to as N/P ratio); A represents a mass percentage of the DTD in the electrolyte; PD represents a compaction density of the anode active material layer in g/cm3; andη represents a viscosity of the electrolyte at 25°C in mPa·s. In some embodiments, the lithium-ion secondary battery satisfies a relationship as follows: 14 ≤ CB × PD/(η × A) ≤ 62. In some embodiments, the CB is 1 to 1.6. In some embodiments, the A is 0.5% to 3%. In some embodiments, the PD is 1 g/cm3 to 2 g/cm3. In some embodiments, the η is 2 mPa·s to 5 mPa·s. In some embodiments, in the anode active material layer, the anode active material comprises at least one of graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, or lithium titanate. In some embodiments, in the anode active material layer, DV50 of the anode active material is 5 µm to 30 µm, and DV50 is a particle size at which a cumulative volume distribution percentage of the anode active material reaches 50%. In some embodiments, in the anode active material layer, an oil absorption value (i.e., DBP value) of the anode active material is 10 mL/100g to 100 mL/100g. In some embodiments, a total mass m of the electrolyte in the lithium-ion secondary battery and a rated capacity cap of the lithium-ion secondary battery satisfy: m/cap = 1.5 g/Ah to 5 g/Ah. In some embodiments, in the electrolyte, the organic solvent comprises at least one of cyclic carbonate, linear carbonate, or carboxylic ester. In some embodiments, in the electrolyte, the lithium salt comprises at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluoroborate, or lithium tetrafluoro(oxalato)borate. In some embodiments, in the electrolyte, the additive further comprises at least one of vinylene carbonate, 1,3-propanesultone, fluoroethylene carbonate, tris(trimethylsilyl) phosphate, or lithium difluorophosphate. In a second aspect, provided herein is an electrical apparatus, comprising the lithium-ion secondary battery. Compared with the prior art, this disclosure has the following beneficial effects: In this disclosure, the parameters related to the anode and the electrolyte of the lithium-ion secondary battery are reasonably designed. Specifically, by controlling the capacity excess coefficient of the battery, the compaction density of the anode, and related parameters of the electrolyte according to a specific relational formula, a calculated value from this formula is made to fall within a specific range, such that poor ion diffusion caused by battery polarization during fast charging or thick electrodes can be avoided, thereby ultimately improving the cycle performance, fast charging performance, and kinetic performance of the battery. Consequently, the fast-charging performance of the lithium-ion secondary battery is significantly improved. DETAILED DESCRIPTION To b