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US-20260128292-A1 - SECONDARY BATTERY AND MANUFACTURING METHOD THEREFOR, AND ELECTRICAL APPARATUS

US20260128292A1US 20260128292 A1US20260128292 A1US 20260128292A1US-20260128292-A1

Abstract

A secondary battery comprises a positive electrode plate and a negative electrode plate. 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 silicon-based material. In the same charging and discharging cycle process, the volume ratio of the negative electrode plate during charging and discharging of the secondary battery is R, wherein R is less than or equal to 1.5; and the volume ratio of the positive electrode plate during charging and discharging of the secondary battery is Y, wherein Y is less than or equal to 0.98.

Inventors

  • Kai Wu
  • Haizu Jin
  • Ning Chen
  • Dongyang Shi
  • Zhi Liu
  • Yaqian Deng
  • Zhipeng Cheng
  • Baiqing Li

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY CO., LIMITED

Dates

Publication Date
20260507
Application Date
20260102
Priority Date
20230601

Claims (20)

  1. 1 . A secondary battery, wherein the secondary battery comprises a positive electrode plate and a negative electrode plate, the negative electrode plate comprises a negative electrode active material layer, and the negative electrode active material layer comprises a negative electrode active material; in the same charging and discharging cycle process, the volume ratio of the negative electrode plate during charging and discharging of the secondary battery is denoted as R, where R≤1.5, and the volume ratio of the positive electrode plate during charging and discharging of the secondary battery is denoted as Y, where Y≤0.98.
  2. 2 . The secondary battery according to claim 1 , wherein the secondary battery satisfies one or more of the following features: R is 1.1 to 1.5; Y is 0.9 to 0.98.
  3. 3 . The secondary battery according to claim 1 , wherein the negative electrode active material comprises a silicon-based material.
  4. 4 . The secondary battery according to claim 3 , wherein the weight proportion of the silicon-based material in the negative electrode active material is denoted as X, and the secondary battery satisfies one or more of the following features: R is 1.1 to 1.5; Y is 0.9 to 0.98; X ≥ 3 ⁢ % ; and 0.8 ≤ R / ( 1.05 · X + ( 1 - X ) · 1.4 ) ≤ 1.2 .
  5. 5 . The secondary battery according to claim 4 , wherein the secondary battery satisfies one or more of the following features: R is 1.1 to 1.4; Y is 0.95 to 0.98; X is 3% to 40%; and 0.8 ≤ R / ( 1.05 · X + ( 1 - X ) · 1.4 ) ≤ 1.1 .
  6. 6 . The secondary battery according to claim 3 , wherein the secondary battery satisfies one or more of the following features: R is 1.15 to 1.4; X is 15% to 25%; and 0.85 ≤ R / ( 1.05 · X + ( 1 - X ) · 1.4 ) ≤ 1.05 .
  7. 7 . The secondary battery according to claim 1 , wherein during the same charge-discharge cycle, the ratio Ra of the total volume of the negative electrode plate and the positive electrode plate during charging to the total volume during discharging is 1.03 to 1.20.
  8. 8 . The secondary battery according to claim 1 , wherein during the same charge-discharge cycle, the volume ratio RN/P of the negative electrode plate to the positive electrode plate during charging or discharging of the secondary battery is 0.7 to 1.6.
  9. 9 . The secondary battery according to claim 8 , wherein during the same charge-discharge cycle, the secondary battery satisfies one or more of the following features: the volume ratio R1 N/P of the negative electrode plate to the positive electrode plate during charging of the secondary battery is 1.0 to 1.6; the volume ratio R2 N/P of the negative electrode plate to the positive electrode plate during discharging of the secondary battery is 0.7 to 1.4; the thickness of the negative electrode plate during charging of the secondary battery is 120 μm to 190 μm; the thickness of the negative electrode plate during discharging of the secondary battery is 80 μm to 180 μm; the thickness of the positive electrode plate during charging of the secondary battery is 100 μm to 130 μm; the thickness of the positive electrode plate during discharging of the secondary battery is 110 μm to 135 μm; the total thickness of the negative electrode plate and the positive electrode plate during charging of the secondary battery is 230 μm to 310 μm; the total thickness of the negative electrode plate and the positive electrode plate during discharging of the secondary battery is 190 μm to 300 μm.
  10. 10 . The secondary battery according to claim 8 , wherein during the same charge-discharge cycle, the secondary battery satisfies one or more of the following features: R1 N/P is 1.0 to 1.55; R2 N/P is 0.8 to 1.35; the thickness of the negative electrode plate during charging of the secondary battery is 130 μm to 190 μm; the thickness of the negative electrode plate during discharging of the secondary battery is 100 μm to 180 μm; the thickness of the positive electrode plate during charging of the secondary battery is 120 μm to 130 μm; the thickness of the positive electrode plate during discharging of the secondary battery is 120 μm to 135 μm; the total thickness of the negative electrode plate and the positive electrode plate during charging of the secondary battery is 250 μm to 310 μm; the total thickness of the negative electrode plate and the positive electrode plate during discharging of the secondary battery is 230 μm to 300 μm.
  11. 11 . The secondary battery according to claim 1 , wherein the negative electrode active material comprises a silicon-based material; the silicon-based material comprises one or more of elemental silicon, a silicon oxide material, a silicon carbon material, a silicon nitrogen composite, and a silicon alloy.
  12. 12 . The secondary battery according to claim 1 , wherein the negative electrode active material comprises a silicon-based material, and the negative electrode active material further comprises one or more of the following materials: a carbon-based material, a tin-based material, and lithium titanate; the carbon-based material comprises one or more of a graphite material, soft carbon, and hard carbon, and the graphite material comprises one or more of artificial graphite and natural graphite.
  13. 13 . The secondary battery according to claim 1 , wherein the negative electrode active material layer comprises carbon nanotubes; optionally, the carbon nanotubes comprise one or more of single-walled carbon nanotubes and multi-walled carbon nanotubes.
  14. 14 . The secondary battery according to claim 1 , wherein the secondary battery is a lithium-ion secondary battery.
  15. 15 . The secondary battery according to claim 1 , wherein the positive electrode plate comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a nickel-containing lithium oxide; in the nickel-containing lithium oxide, the total atomic stoichiometric number of non-lithium and non-oxygen elements is taken as 1, the atomic stoichiometric number of nickel element is denoted as n, and n≥0.7.
  16. 16 . The secondary battery according to claim 1 , wherein the positive electrode plate comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a nickel-containing lithium oxide; in the nickel-containing lithium oxide, the total atomic stoichiometric number of non-lithium and non-oxygen elements is taken as 1, the atomic stoichiometric number of nickel element is denoted as n, the positive electrode plate satisfies Y≤1.14−0.2n, and n≥0.8.
  17. 17 . The secondary battery according to claim 1 , wherein the positive electrode plate comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises one or more of a ternary material and a modified ternary material, wherein the modified ternary material is a ternary material containing a modifying element, and the modifying element exists as a doping element, as a coating element, or as a combination of doping element and coating element.
  18. 18 . The secondary battery according to claim 17 , wherein the secondary battery satisfies one or more of the following features: the positive electrode active material comprises one or more of a NCM ternary material, a NCA ternary material, a modified NCM ternary material, and a modified NCA material; wherein the modified NCM ternary material is an NCM ternary material containing the modifying element, and the modified NCA ternary material is an NCA ternary material containing the modifying element; the modifying element in the modified ternary material comprises one or more of Na, K, Ca, Ba, Sb, Ti, Zr, W, Sr, Nb, Mo, Si, Mg, B, Cr and Ta; the chemical formula of the positive electrode active material is Li x (Ni a Co b M c M′ d )O 2-e , where 0.6≤x≤1.2, 0<a<1, 0<b<1, 0<c<1, 0<d<1, a+b+c+d=1, −0.1≤e≤0.1, M comprises at least one of Mn and Al, and M′ comprises one or more of Na, K, Ca, Ba, Sb, Ti, Zr, W, Sr, Nb, Mo, Si, Mg, B, Cr and Ta; the positive electrode active material comprises a nickel-containing lithium oxide; in the nickel-containing lithium oxide, the total atomic stoichiometric number of non-lithium and non-oxygen elements is taken as 1, the atomic stoichiometric number of nickel element is denoted as n, and the positive electrode plate satisfies Y≤1.14−0.2n.
  19. 19 . The secondary battery according to claim 1 , wherein the negative electrode active material layer comprises a negative electrode active material, a binder, and a conductive agent; the positive electrode plate comprises a positive electrode active material layer, and the positive electrode active material layer comprises a positive electrode active material, a binder, and a conductive agent.
  20. 20 . An electrical apparatus, comprising the secondary battery according to claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International Application No. PCT/CN2023/119077, filed on Sep. 15, 2023, which claims priority to Chinese Patent Application No. 202310639708.0, filed on Jun. 1, 2023, and titled “SECONDARY BATTERY AND MANUFACTURING METHOD THEREFOR, AND ELECTRICAL APPARATUS,” each of which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present application relates to the technical field of secondary batteries, and in particular, to a secondary battery and a manufacturing method therefor, and an electrical apparatus. BACKGROUND The statement here merely provides background information related to the present application, and does not necessarily constitute the prior art. With the development of various electronic products such as smart phones, tablets, smart wearables, electric tools and electric vehicles, the requirements for the performance of secondary batteries have become increasingly higher. The silicon-based material has such advantages as low costs and high specific capacity, and therefore is a highly favored negative electrode material. However, silicon-based negative electrodes suffer from severe volume expansion, making them an expandable negative electrode material that can lead to significant deterioration in battery cycling performance and severely impact battery life. SUMMARY OF THE DISCLOSURE In view of the aforementioned problems, the present application provides a secondary battery and a manufacturing method therefor, and an electrical apparatus. The secondary battery comprises an expandable negative electrode plate, which has reduced volume expansion of the negative electrode plate and volume expansion of the battery cell, thus suppressing the damage to the battery cycle life caused by the expansion of the negative electrode material. When the secondary battery comprises a silicon-containing negative electrode plate, it has reduced volume expansion of the negative electrode plate and volume expansion of the battery cell, thus suppressing the damage to the battery cycle life caused by silicon expansion. In a first aspect, the present application provides a secondary battery, the secondary battery comprises a positive electrode plate and a negative electrode plate, the negative electrode plate comprises a negative electrode active material layer, and the negative electrode active material layer comprises a negative electrode active material. In the same charging and discharging cycle process, the volume ratio of the negative electrode plate during charging and discharging of the secondary battery is denoted as R, where R≤1.5, and the volume ratio of the positive electrode plate during charging and discharging of the secondary battery is denoted as Y, where Y≤0.98. When the secondary battery is charged and discharged, the electrode plate may shrink or expand due to factors such as the intercalation and deintercalation behavior of active ions and changes in grain spacing. When the secondary battery is charged, active ions are intercalated into the negative electrode plate, causing the electrode plate to expand, while active ions are deintercalated from the positive electrode plate, causing the electrode plate to shrink. When the secondary battery is discharged, active ions are deintercalated from the negative electrode plate, causing the electrode plate to shrink back, while active ions are reversibly intercalated into the positive electrode plate, causing the electrode plate volume to increase again. In the same charging and discharging cycle process, the volume ratio R of the negative electrode plate during charging and discharging of the secondary battery can reflect the degree of reversible expansion of the negative electrode plate. It is necessary to keep the R value within 150%, that is, R≤1.5. If the R value is too large, the binder may not be able to withstand the large stress in the expansion and shrinkage process. It may also cause the electrical contact of the negative electrode active material to deteriorate due to the expansion of the electrode plate volume, which may lead to the damage to the conductive network in the negative electrode plate. It may even cause the negative electrode plate structure to collapse during battery cycling, resulting in premature failure of the battery cell. In the aforementioned charging and discharging cycle process, the volume ratio Y of the positive electrode plate during charging and discharging of the secondary battery can reflect the degree of reversible shrinkage of the positive electrode plate, and a Y value not exceeding 0.98 helps to enable the battery cell to resist the expansion of the negative electrode plate as a whole. The secondary battery provided in the present application, through the shrinkage-expansion matching design of the positive electrode plate and the expandable negative electrode plate, can significantly reduce the volume expansio