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EP-4742349-A1 - SECONDARY BATTERY AND ELECTRICAL DEVICE

EP4742349A1EP 4742349 A1EP4742349 A1EP 4742349A1EP-4742349-A1

Abstract

A secondary battery and an electrical device are provided. In the present disclosure, by controlling a negative electrode plate of the secondary battery, a negative electrode active material and an electrolyte to satisfy Formula (I), the secondary battery can be ensured to have excellent cycling and storage stability: 0.35 ≤ m × C × P × D V 50 W ≤ 12.0

Inventors

  • CHENG, Shouqiang
  • LI, LEI

Assignees

  • Sunwoda Mobility Energy Technology Co., Ltd.

Dates

Publication Date
20260513
Application Date
20240122

Claims (10)

  1. A secondary battery, comprising a positive electrode plate, a negative electrode plate, an electrolyte, and a separator, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer comprises a negative electrode active material, the electrolyte comprises a phosphate ester additive, and the secondary battery satisfies a relationship as follows: 0.35 ≤ m × C × P × D V 50 W ≤ 12.0 wherein m , in g/Ah, represents a filling coefficient of the electrolyte in the secondary battery; C represents a percent concentration by mass of the phosphate ester additive in the electrolyte of the secondary battery; P, in g/cm 3 , represents a compaction density of the negative electrode active material layer; D V50 , in µm, represents a particle size of the negative electrode active material at 50% of cumulative volume distribution; W, in g/1540.25 mm 2 , represents an areal density of the negative electrode active material layer.
  2. The secondary battery according to claim 1, wherein the secondary battery satisfies a relationship as follows: 1.9 ≤ m × C × P × D V 50 W ≤ 3.0 . .
  3. The secondary battery according to claim 1, wherein the filling coefficient m , in g/Ah, of the electrolyte is in a range of from 2 g/Ah to 5 g/Ah.
  4. The secondary battery according to claim 1, wherein the percent concentration by mass C of the phosphate ester additive in the electrolyte is in a range of from 0.1wt% to 3 wt%.
  5. The secondary battery according to claim 1, wherein the compaction density P , in g/cm 3 , of the negative electrode active material layer is in a range of from 1.2 g/cm 3 to 1.8 g/cm 3 .
  6. The secondary battery according to claim 1, wherein the D V50 , in µm, of the negative electrode active material is in a range of from 4µm to 18 µm.
  7. The secondary battery according to claim 1, wherein the areal density W , in g/1540.25 mm 2 , of the negative electrode active material layer is in a range of from 0.08 g/1540.25 mm 2 to 0.28 g/1540.25 mm 2 .
  8. The secondary battery according to any one of claims 1-7, wherein the electrolyte comprises a lithium salt and an organic solvent, and the electrolyte satisfies at least one selected from the group consisting of conditions (1)-(3) as follows: (1) the lithium salt comprises at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, lithium difluoro(bisoxalato)phosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluoro(oxalato)borate, and lithium bis(oxalato)borate; (2) the phosphate ester additive comprises at least one selected from the group consisting of tris(trimethylsilyl)phosphate and tripropargyl phosphate; (3) the organic solvent comprises at least one selected from the group consisting of a cyclic carbonate, a chain carbonate, and a chain carboxylate.
  9. The secondary battery according to any one of claims 1-7, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, the positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a lithium nickel cobalt oxide and/or a lithium iron oxide; and/or the negative electrode active material comprises at least one selected from the group consisting of graphite and a silicon-based material.
  10. An electrical device, comprising the secondary battery according to any one of claims 1-9.

Description

TECHNICAL FIELD The present disclosure relates to the field of battery technology, in particular to a secondary battery and an electrical device. BACKGROUND In recent years, batteries, such as lithium-ion batteries, have been widely used in the field of consumer electronics due to their advantages, including high voltage platforms, high energy density, absence of memory effect, and long lifespan. At the same time, increasingly severe global environmental challenges, fossil fuel shortages and the like are rapidly driving the development of electric vehicles. As core components of electric vehicles, lithium-ion batteries are confronted with increasing demands for improved cycling performance and storage stability. Therefore, there is an urgent need for a secondary battery with excellent cycling and storage stability. SUMMARY OF THE DISCLOSURE To provide a secondary battery with excellent cycling and storage stability, in the present disclosure, by comprehensively designing a negative electrode plate of the secondary battery, intrinsic parameters of a negative electrode active material and an additive amount of an electrolyte additive, an appropriate additive range of the electrolyte additive can be rapidly determined, thereby ensuring that the secondary battery satisfies the requirements for good performance. To achieve the above objective, in a first aspect, the present disclosure provides a secondary battery, including a positive electrode plate, a negative electrode plate, an electrolyte and a separator, where the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer includes a negative electrode active material, the electrolyte includes a phosphate ester additive, and the secondary battery satisfies a relationship as follows: 0.35≤m×C×P×DV50W≤12.0, where m, in g/Ah, represents a filling coefficient of the electrolyte in the secondary battery;C represents a percent concentration by mass of the phosphate ester additive in the electrolyte of the secondary battery;P, in g/cm3, represents a compaction density of the negative electrode active material layer;DV50, in µm, represents a particle size of the negative electrode active material at 50% of cumulative volume distribution;W, in g/1540.25 mm2, represents an areal density of the negative electrode active material layer. In some embodiments, the secondary battery satisfies a relationship as follows: 1.9≤m×C×P×DV50W≤3.0. In some embodiments, the filling coefficient m, in g/Ah, of the electrolyte is in a range of from 2 g/Ah to 5 g/Ah. In some embodiments, the percent concentration by mass C of the phosphate ester additive in the electrolyte is in a range of from 0.1wt% to 3 wt%. In some embodiments, the compaction density P, in g/cm3, of the negative electrode active material layer is in a range of from 1.2 g/cm3 to 1.8 g/cm3. In some embodiments, the DV50, in µm, of the negative electrode active material is in a range of from 4µm to 18 µm. In some embodiments, the areal density W, in g/1540.25mm2, of the negative electrode active material layer is in a range of from 0.08 g/1540.25mm2 to 0.28 g/1540.25mm2. In some embodiments, the electrolyte further includes a lithium salt, and the lithium salt includes at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, lithium difluoro(bisoxalato)phosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium difluoro(oxalato)borate, and lithium bis(oxalato)borate. In some embodiments, the electrolyte further includes an organic solvent, and the organic solvent includes at least one selected from the group consisting of a cyclic carbonate, a chain carbonate, and a chain carboxylate. In some embodiments, the phosphate ester additive includes at least one selected from the group consisting of tris(trimethylsilyl)phosphate and tripropargyl phosphate. In some embodiments, the positive electrode plate includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material includes a lithium nickel cobalt oxide and/or a lithium iron oxide. In some embodiments, the negative electrode active material includes at least one selected from the group consisting of graphite and a silicon-based material. In a second aspect, the present disclosure provides an electrical device, including the aforementioned secondary battery. Compared to the prior art, the present disclosure has the following beneficial effects: In the present disclosure, by controlling the design of the negative electrode plate of the battery