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CN-122000427-A - Battery cell and electricity utilization device

CN122000427ACN 122000427 ACN122000427 ACN 122000427ACN-122000427-A

Abstract

The application provides a battery cell and an electric device. The battery cell comprises an electric core, the electric core comprises an anode plate, a cathode plate and a diaphragm arranged between the anode plate and the cathode plate, the anode plate, the cathode plate and the diaphragm extend along a first direction, the lengths of the anode plate, the cathode plate and the diaphragm along the first direction are larger than those along a second direction, the second direction is perpendicular to the first direction and the same as the height direction of a battery cell, the anode plate, the cathode plate and the diaphragm are laminated along a third direction, the third direction is perpendicular to the first direction and the second direction, the cathode plate comprises a cathode current collector and a cathode film layer positioned on at least one side of the cathode current collector, the compaction density of the cathode film layer is 1.5g/cm 3 -1.78g/cm 3 , the diaphragm comprises a base film and a coating positioned on at least one side of the base film, the coating comprises organic particles, and the quantity accumulated distribution particle size D50 of the organic particles is 10-18 mu m.

Inventors

  • CAO JIAN
  • ZHANG HUAJIE

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251211

Claims (20)

  1. 1. A battery cell is characterized by comprising an electric core and a shell, wherein the electric core comprises a positive pole piece, a negative pole piece and a diaphragm arranged between the positive pole piece and the negative pole piece, The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer positioned on at least one side of the negative electrode current collector, wherein, The compaction density of the negative electrode film layer is 1.5g/cm 3 -1.78g/cm 3 ; the separator comprises a base film and a coating layer positioned on at least one side of the base film, wherein the coating layer comprises organic particles, and the number cumulative distribution particle diameter D50 of the organic particles is 10-18 mu m.
  2. 2. The battery cell of claim 1, wherein the negative electrode tab has a compacted density of 1.60g/cm 3 -1.70g/cm 3 .
  3. 3. The battery cell according to claim 1 or 2, wherein the negative electrode current collector has a thickness of 3 μm to 6 μm and/or the negative electrode current collector has a tensile strength of 300Mpa to 550Mpa.
  4. 4. The battery cell according to claim 3, wherein the negative electrode current collector has a thickness of 4 μm to 5 μm and/or a tensile strength of 400Mpa to 450Mpa.
  5. 5. The battery cell of any one of claims 1-4, wherein the negative current collector has a thickness ratio of 2.69% -4.87% based on the thickness of the negative electrode tab.
  6. 6. The battery cell of any one of claims 1-5, wherein the negative current collector has an elongation at break of 2% -4%.
  7. 7. The battery cell of any one of claims 1-6, wherein the negative electrode sheet has a coating weight of 0.1g/1540mm 2 -0.2g/1540mm 2 .
  8. 8. The battery cell of any one of claims 1-7, wherein the organic particles have a D50 of 10 μιη to 14 μιη in the coating.
  9. 9. The battery cell of any one of claims 1-8, wherein the material of the organic particles comprises one or more of polyacrylic polymers, polyvinylidene fluoride polymers, polyacrylonitrile polymers, polyimide polymers.
  10. 10. The battery cell of any one of claims 1-8, wherein the base film has a thickness of 5 μιη to 12 μιη.
  11. 11. The battery cell of any one of claims 1-10, wherein the separator further comprises a ceramic layer on both sides of the base film, the ceramic coating being located between the base film and the coating.
  12. 12. The battery cell of claim 11, wherein the ceramic layer has a thickness of 0.8 μιη to 1.2 μιη.
  13. 13. The battery cell of any one of claims 1-12, wherein the positive electrode tab comprises a positive electrode current collector and a positive electrode active material layer on at least one side of the positive electrode current collector, wherein, The positive electrode film layer has a compacted density of 2.50g/cm 3 -2.80g/cm 3 , and/or the positive electrode current collector has a thickness of 9 μm to 15 μm, and/or the positive electrode current collector has a tensile strength of 200Mpa to 400Mpa.
  14. 14. The battery cell of claim 13, wherein the positive electrode sheet has a compacted density of 2.65g/cm 3 -2.8g/cm 3 , and/or the positive electrode current collector has a thickness of 9-13 μm, and/or the positive electrode current collector has a tensile strength of 230-270 Mpa.
  15. 15. The battery cell of claim 13 or 14, wherein the positive current collector has a thickness ratio of 4.56% -7.74% based on the thickness of the positive electrode tab.
  16. 16. The battery cell of any one of claims 13-15, wherein the positive electrode current collector has an elongation at break of 0.6% -3%.
  17. 17. The battery cell of any one of claims 13-16, wherein the positive electrode sheet has a coating weight of 0.3g/1540mm 2 -0.4g/1540mm 2 .
  18. 18. The battery cell according to any one of claims 1 to 17, wherein the battery cell is a wound battery cell, the positive electrode tab, the negative electrode tab, and the separator are stacked in a predetermined order and wound to form, and in a cross section perpendicular to an axial direction Y of the wound battery cell, the wound battery cell includes a large area in which the positive electrode tab, the negative electrode tab, and the separator are stacked in a second direction Z, and a bending area located on both sides of the large area in the first direction X, the first direction X being perpendicular to the second direction Z and perpendicular to the axial direction Y, And taking the bending position of the diaphragm of the innermost layer in the winding battery core as a starting point, wherein the second direction is 45 degrees, and in the bending region, the average gap between the positive electrode pole piece or the negative electrode pole piece and the adjacent diaphragm is 30-40 mu m.
  19. 19. The battery cell according to any one of claims 1 to 18, wherein the positive electrode sheet surface is provided with depressions having a density of 4 to 8/cm 2 and a depth of 5 μm to 10 μm at the deepest part of the depressions.
  20. 20. The battery cell of any one of claims 1-19, wherein the height of the cell is 150mm or greater.

Description

Battery cell and electricity utilization device Technical Field The application relates to the technical field of lithium batteries, in particular to a battery monomer and an electric device. Background In recent years, along with the wider application range of lithium ion batteries, the lithium ion batteries are widely applied to energy storage power supply systems such as hydraulic power, firepower, wind power, solar power stations and the like, and a plurality of fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, aerospace and the like. As lithium ion batteries have been greatly developed, higher demands are also being made on energy density, cycle performance, safety performance, and the like. Disclosure of Invention The present application has been made in view of the above problems, and an object thereof is to provide a battery cell and an electric device. The battery unit can give consideration to high energy density, good cycle performance and safety performance. To this end, a first aspect of the present application provides a battery cell, which comprises a battery cell and a housing, wherein the battery cell comprises a positive electrode plate, a negative electrode plate and a separator arranged between the positive electrode plate and the negative electrode plate, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer positioned on at least one side of the negative electrode current collector, the compaction density of the negative electrode film layer is 1.5g/cm 3-1.78g/cm3, the separator comprises a base film and a coating positioned on at least one side of the base film, the coating comprises organic particles, and the number cumulative distribution particle size D50 of the organic particles is 10 μm-18 μm. Therefore, the energy density of the battery monomer is improved, and meanwhile, the structural stability of the pole piece and the electrolyte infiltration effect are improved, so that the safety performance and the cycle performance of the battery monomer are both considered. In some embodiments, the negative electrode tab has a compacted density of 1.60g/cm 3-1.70g/cm3, thereby further facilitating the cell to have a high energy density. In some embodiments, the negative electrode current collector has a thickness of 3 μm to 6 μm and/or the negative electrode current collector has a tensile strength of 300Mpa to 550Mpa. Therefore, the battery cell is favorable for combining high energy density with good cycle performance and safety performance. In some embodiments, the negative electrode current collector has a thickness of 4 μm to 5 μm and/or a tensile strength of 400Mpa to 450Mpa. Therefore, the battery cell is further beneficial to the combination of high energy density, good cycle performance and safety performance. In some embodiments, the negative current collector has a thickness ratio of 2.69% -4.87% based on the thickness of the negative electrode tab. Therefore, the volume occupied by the current collector is reduced, and the energy density of the battery monomer is improved. In some embodiments, the negative electrode current collector has an elongation at break of 2% to 4%. Therefore, the structural stability of the negative electrode plate is improved, and the safety performance and the cycle performance of the battery cell are improved. In some alternative embodiments, the negative electrode current collector has an elongation at break of 2.8% to 3.2%. In some embodiments, the coating weight of the negative electrode sheet is 0.1g/1540mm 2-0.2g/1540mm2. Thereby, the energy density of the battery cell is advantageously increased. In some embodiments, the organic particles have a D50 of 10 μm to 14 μm in the coating. Therefore, the breaking risk of the pole piece is reduced, and the safety performance and the cycling stability of the battery monomer are improved. In some embodiments, the material of the polymer particles comprises one or more of polyacrylic polymers, polyvinylidene fluoride polymers, polyacrylonitrile polymers, polyimide polymers. Thus, the cycle performance of the battery cell is improved. In some embodiments, the base film has a thickness of 5 μm to 12 μm. In some alternative embodiments, the base film has a thickness of 5 μm to 9 μm. In some embodiments, the separator further comprises a ceramic layer located on both sides of the base film, the ceramic layer being located between the base film and the coating. Therefore, the risk of diaphragm puncture and electric core thermal runaway is reduced, the infiltration effect of electrolyte is improved, and the safety performance and the cycle performance of the battery monomer are improved. In some embodiments, the ceramic layer has a thickness of 0.8 μm to 1.2 μm. Therefore, the safety performance of the battery is improved, and the energy density of the battery monomer is considered. In some embodiments, th