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CN-121983636-A - Battery and battery pack

CN121983636ACN 121983636 ACN121983636 ACN 121983636ACN-121983636-A

Abstract

The application provides a battery, which belongs to the technical field of batteries, and comprises a positive plate, wherein the positive plate comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises a phosphate positive electrode material and a nickel cobalt lithium manganate monocrystal, the nickel cobalt lithium manganate monocrystal accounts for M% and is 0< M < 50, the negative plate comprises a negative electrode active material layer, the negative electrode active material layer comprises a negative electrode active material, the negative electrode active material comprises a carbon-based active material, and the OI value of the carbon-based active material is Y and is less than or equal to 0.1M+5. According to the application, through the synergistic cooperation of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal proportion and the two groups of the carbon-based active material OI value and the phosphate positive electrode material dosage adaptation, the DCR growth of the battery can be greatly inhibited, and the quick charge performance of the battery can be improved.

Inventors

  • HU JUN
  • LIANG QIUYI
  • ZHU ZHENHAI
  • ZOU ZHIQUN
  • ZHANG LIN

Assignees

  • 惠州亿纬动力电池有限公司

Dates

Publication Date
20260505
Application Date
20251218

Claims (10)

  1. 1. A battery, comprising: the positive plate comprises a positive electrode active material layer, wherein the positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises a phosphate positive electrode material and a nickel cobalt lithium manganate monocrystal, the nickel cobalt lithium manganate monocrystal accounts for M% of the total mass of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal, the mass percentage of the nickel cobalt lithium manganate monocrystal is 0< M < 50, and The negative electrode plate comprises a negative electrode active material layer, the negative electrode active material layer comprises a negative electrode active material, the negative electrode active material comprises a carbon-based active material, and the OI value of the carbon-based active material is Y which is less than or equal to 0.1M+5.
  2. 2. The battery according to claim 1, it is characterized in that the method comprises the steps of, M is more than or equal to 20 and less than or equal to 50.
  3. 3. The battery of claim 1, wherein 0.1 m≤y≤0.1m+5.
  4. 4. The battery according to any one of claims 1 to 3, wherein the phosphate-based positive electrode material has a D50 particle diameter of R1, and the lithium nickel cobalt manganese oxide single crystal has a D50 particle diameter of R2, wherein R1 is not more than 0.5R2.
  5. 5. The battery according to any one of claims 1 to 3, wherein the phosphate-based positive electrode material has a D50 particle diameter of 0.5 μm to 1.5 μm, and the lithium nickel cobalt manganese oxide single crystal has a D50 particle diameter of 3 μm to 10 μm.
  6. 6. The battery according to any one of claims 1 to 5, wherein the carbon-based active material comprises graphite, and/or, The phosphate-based positive electrode material includes at least one of lithium iron phosphate and lithium manganese iron phosphate.
  7. 7. The battery of claim 6, wherein the lithium iron manganese phosphate has a chemical formula of LiMn x Fe y PO 4 , wherein 0.5≤x≤0.7, x+y=1, and/or, The chemical formula of the lithium nickel cobalt manganese oxide monocrystal is LiNi a Co b Mn c O 2 , wherein a is more than or equal to 0.5 and less than or equal to 0.9, b is more than or equal to 0 and less than or equal to 0.3, and a+b+c=1.
  8. 8. The battery according to any one of claims 1 to 7, wherein a carbon coating layer is provided on the surface of the phosphate-based positive electrode material, and the carbon coating layer accounts for 1.0% -2.5% of the total mass of the phosphate-based positive electrode material and the carbon coating layer.
  9. 9. The battery according to any one of claims 1 to 8, further comprising an electrolyte and a separator, the separator being disposed between the positive electrode sheet and the negative electrode sheet.
  10. 10. A battery pack comprising the battery according to any one of claims 1 to 9.

Description

Battery and battery pack Technical Field The application relates to the technical field of batteries, in particular to a battery and a battery pack. Background Lithium ion batteries are widely used in electric vehicles, hybrid vehicles and energy storage systems because of their high energy density, long cycle life, environmental protection, and the like. The phosphate positive electrode material such as lithium manganese iron phosphate (LMFP) positive electrode material has a higher voltage platform, is favorable for improving the cruising ability of the electric automobile, has better safety performance, and is widely applied to the field of light power. With the increasing speed of life, the demand of the light power industry for the fast battery charging capability is increasing, and the fast battery charging is not supported initially until the fast battery charging is carried out for 1h, then 30min or even faster. However, lithium iron manganese phosphate has low electron conductivity and low lithium ion diffusion coefficient, resulting in low fast charge capacity. In the related art, ternary materials of lithium iron manganese phosphate and lithium nickel cobalt manganese oxide (NCM) are blended, so that the quick charge performance of the battery is improved. However, the quick charge performance of the battery is also affected by the negative electrode material, and the increase of direct current internal resistance (DCR) cannot be effectively inhibited only by simple combination of lithium iron manganese phosphate and lithium nickel cobalt manganese oxide in the positive electrode material, so that the quick charge performance of the battery is affected. Disclosure of Invention The application provides a battery and a battery pack, and aims to solve the problem that the increase of direct current internal resistance cannot be effectively restrained only by simple compounding of a phosphate positive electrode material and nickel cobalt lithium manganate, so that the quick charge performance of the battery is affected. In a first aspect, embodiments of the present application provide a battery comprising: The positive plate comprises a positive electrode active material layer, wherein the positive electrode active material layer comprises a positive electrode active material, the positive electrode active material layer comprises a phosphate positive electrode material and a nickel cobalt lithium manganate monocrystal, the nickel cobalt lithium manganate monocrystal accounts for M% of the total mass of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal, the mass percentage of the nickel cobalt lithium manganate monocrystal is 0< M < 50, and the nickel cobalt lithium manganate monocrystal is a metal alloy material The negative electrode plate comprises a negative electrode active material layer, the negative electrode active material layer comprises a negative electrode active material, the negative electrode active material comprises a carbon-based active material, and the OI value of the carbon-based active material is Y which is less than or equal to 0.1M+5. According to the application, the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal are compounded, the proportion of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal is controlled, so that the synergistic effect of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal is better, the DCR growth of the battery can be greatly inhibited, the quick charge capacity of the battery is improved, the battery has the advantages of high energy density and high capacity retention rate, then the OI value of the negative electrode active material in the negative electrode active material layer, namely the carbon-based active material, can provide more abundant transmission channels and intercalation sites for lithium ions, improves the transmission efficiency of the lithium ions, and can select the crystal structure of the adaptive carbon-based active material according to the proportion of the nickel cobalt lithium manganate monocrystal in the positive electrode active material, so that the rate of releasing lithium ions of the positive electrode active material and the rate of receiving lithium ions in the charging process of the negative electrode active material are well regulated, the DCR growth of the battery in the charging process is further effectively inhibited, and the quick charge capacity of the battery is improved. Alternatively, the process may be carried out in a single-stage, M is more than or equal to 20 and less than or equal to 50. According to the application, the proportion of the phosphate positive electrode material and the nickel cobalt lithium manganate monocrystal in the positive electrode active material is further optimized, so that the phosphate positive electrod