Search

US-12620633-B2 - Lithium-ion battery and electric device

US12620633B2US 12620633 B2US12620633 B2US 12620633B2US-12620633-B2

Abstract

Embodiments of the present application disclose a lithium-ion battery and an electric device. The lithium-ion battery includes an electrolyte including a metal ion, where a reduction potential of the metal ion is higher than a reduction potential of a lithium ion; and a low CB value region, where a CB value of the lithium ion in the low CB value region satisfies: 0<CB<1, and the CB value is a ratio of a capacity of a negative electrode active material per unit area to a capacity of a positive electrode active material per unit area. The lithium-ion battery provided in the present application can effectively solve the problem of lithium deposition in the low CB value region.

Inventors

  • Kai Wu
  • Hao Jiang
  • Chenglong Yang
  • Jingyu Gao
  • Aosai CHEN
  • HaiMing Zhang
  • Honggang YU
  • Haizu Jin
  • Li Luo

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY CO., LIMITED

Dates

Publication Date
20260505
Application Date
20250731
Priority Date
20230630

Claims (19)

  1. 1 . A lithium-ion battery, comprising: an electrolyte comprising a metal ion, wherein a reduction potential of the metal ion is higher than a reduction potential of a lithium ion; a negative electrode plate; and a low cell balance (CB) value region, wherein a CB value of the lithium-ion battery in the low CB value region satisfies: 0<CB<1, and the CB value is a ratio of a capacity of a negative electrode active material per unit area to a capacity of a positive electrode active material per unit area, and wherein a percentage X of an area of the negative electrode plate corresponding to the low CB value region in an area of the negative electrode plate satisfies: 0%<X≤10%.
  2. 2 . The lithium-ion battery according to claim 1 , wherein the CB value of the lithium-ion battery at the low CB value region satisfies: 0.5<CB<1.
  3. 3 . The lithium-ion battery according to claim 1 , wherein a reduction potential φ(Mn+/M) of the metal ion satisfies: φ(Mn+/M)+(RTlnC)/F≥φ(Li+/Li), wherein Mn+ represents the metal ion, n represents a valence of the metal ion, C represents a molar concentration of the metal ion in the electrolyte, R represents an ideal gas constant, T represents a temperature, F represents the Faraday constant, and φ(Li+/Li) represents a standard electrode potential of the lithium ion.
  4. 4 . The lithium-ion battery according to claim 1 , wherein the reduction potential φ(Mn+/M) of the metal ion satisfies: φ(Mn+/M)+(RTlnC)/F≤3 V vs. Li+/Li.
  5. 5 . The lithium-ion battery according to claim 1 , wherein the molar concentration C of the metal ion in the electrolyte satisfies: 0.001 M≤C≤0.2 M.
  6. 6 . The lithium-ion battery according to claim 1 , wherein the metal ion comprises at least one of Mg2+, Al3+, Zn2+and Sb2+.
  7. 7 . A lithium-ion battery, comprising: an electrolyte comprising a metal ion, wherein a reduction potential of the metal ion is higher than a reduction potential of a lithium ion; a low cell balance (CB) value region, wherein a CB value of the lithium-ion battery in the low CB value region satisfies: 0<CB<1; and a negative electrode plate, wherein, after cycling of the lithium-ion battery, a content m1 of a metal element corresponding to the metal ion per unit area at the negative electrode plate corresponding to the low CB value region is greater than a content m2 of the metal element corresponding to the metal ion per unit area at the negative electrode plate corresponding to a high CB value region, wherein a CB value of the lithium-ion battery in the high CB value region satisfies: CB≥1; the CB value is a ratio of a capacity of a negative electrode active material per unit area to a capacity of a positive electrode active material per unit area; and a reduction potential of a metal ion corresponding to the metal element is higher than a reduction potential of a lithium ion.
  8. 8 . The lithium-ion battery according to claim 7 , wherein a percentage X of an area of the negative electrode plate corresponding to the low CB value region in an area of the negative electrode plate satisfies: 0%<X≤10%.
  9. 9 . The lithium-ion battery according to claim 7 , wherein a CB value of the lithium-ion battery at the low CB value region satisfies: 0.5<CB<1.
  10. 10 . The lithium-ion battery according to claim 7 , wherein the metal element comprises at least one of Mg, Al, Zn and Sb.
  11. 11 . The lithium-ion battery according to claim 7 , comprising: an electrolyte comprising a metal ion, wherein the metal ion is an ion corresponding to the metal element.
  12. 12 . The lithium-ion battery according to claim 11 , wherein, after cycling of the lithium-ion battery, a molar concentration C′ of the metal ion in the electrolyte satisfies: 0≤C′<0.2 M.
  13. 13 . An electric device, wherein the electric device comprises the lithium-ion battery according to claim 1 .
  14. 14 . An electric device, wherein the electric device comprises the lithium-ion battery according to claim 7 .
  15. 15 . The lithium-ion battery according to claim 1 , wherein the CB value in the low CB value region satisfies: 0.9<CB<1.
  16. 16 . The lithium-ion battery according to claim 6 , wherein the metal ion comprises Sb2+.
  17. 17 . The lithium-ion battery according to claim 7 , wherein the CB value in the low CB value region satisfies: 0.9<CB<1.
  18. 18 . The lithium-ion battery according to claim 10 , wherein the metal element comprises Sb.
  19. 19 . The lithium-ion battery according to claim 7 , wherein a ratio of m1/m2 is from 5.1 to 322.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This patent document is a continuation of PCT Application No. PCT/CN2023/134415, filed on Nov. 27, 2023, which claims priority to and the benefit of Chinese Patent Application No. 202310794171.5 filed on Jun. 30, 2023 entitled “LITHIUM-ION BATTERY AND ELECTRIC DEVICE”. The entire content of the above patent application is incorporated by reference into a part of the disclosure of this patent document. TECHNICAL FIELD The present application relates to the field of batteries, and more particularly, to a lithium-ion battery and an electric device. BACKGROUND In recent years, lithium-ion batteries have been widely used in energy storage power supply systems such as hydropower, thermal power, wind power and solar power plants, as well as in multiple fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment and aerospace, and thus have achieved great development. In the preparation process of lithium-ion batteries, due to process limitations, a position where the capacities of the positive and negative electrodes are not matched will inevitably occur, that is, there will be a low CB value region. The negative electrode plate corresponding to the low CB value region easily undergoes lithium deposition, which adversely affects the capacity and safety of lithium-ion batteries. Therefore, how to improve the influence of lithium deposition on the performance of ion batteries is an urgent technical problem to be solved. SUMMARY The present application is made in view of the above technical problem, and an objective thereof is to provide a lithium-ion battery and an electric device. The lithium-ion battery includes an electrolyte containing a metal ion, which can effectively improve the problem of lithium deposition in a low CB value region. In a first aspect, a lithium-ion battery is provided, including: an electrolyte including a metal ion, where a reduction potential of the metal ion is higher than a reduction potential of a lithium ion; and a low CB value region, where a CB value of the lithium-ion battery in the low CB value region satisfies: 0<CB<1, and the CB value is a ratio of a capacity of a negative electrode active material per unit area to a capacity of a positive electrode active material per unit area. At the low CB value region of the lithium-ion battery, the CB value is less than 1. In other words, the capacity of the positive electrode active material per unit area is larger than the capacity of the negative electrode active material per unit area in the low CB value region. Therefore, lithium deposition easily occurs at a negative electrode plate corresponding to the low CB value region in the cycling process. In embodiments of the present application, the metal ion with a reduction potential higher than that of the lithium ion is introduced into the electrolyte. When lithium deposition occurs at the negative electrode plate corresponding to the low CB value region, the metal ion in the electrolyte can freely move to a position of lithium deposition and be reduced to a metal simple substance by lithium. Thus, the situation of lithium deposition in the low CB value region is improved, which helps to increase the reversible capacity and cycling performance of the lithium-ion battery. In a possible implementation, the lithium-ion battery includes a negative electrode plate, where a percentage X of an area of the negative electrode plate corresponding to the low CB value region in an area of the negative electrode plate satisfies: 0%<X; optionally, 0%<X≤10%; and optionally, 0%<X≤2%. In a possible implementation, a CB value of the lithium-ion battery in the low CB value region satisfies: 0.5<CB<1. In a possible implementation, a reduction potential φ(Mn+/M) of the metal ion satisfies: φ(Mn+/M)+(RTlnC)/F≥φ(Li+/Li), where Mn+ represents the metal ion, n represents a valence of the metal ion, C represents a molar concentration of the metal ion in the electrolyte, R represents an ideal gas constant, T represents a temperature, F represents the Faraday constant, and φ(Li+/Li) represents a standard electrode potential of the lithium ion. In embodiments of the present application, by selecting a metal ion whose reduction potential meets the above conditions, the metal ion can be reduced to a metal simple substance by deposited lithium, thereby improving the problem of lithium deposition in the low CB value region. In a possible implementation, the reduction potential φ(Mn+/M) of the metal ion satisfies: φ(Mn+/M)+(RTlnC)/F≤3 V vs. Li+/Li. In embodiments of the present application, by selecting a metal ion whose reduction potential meets the above conditions, while the metal ion can be reduced by lithium, it helps to reduce the oxidizing property of the metal ion, thereby reducing the influence of the metal ion on the electrolyte and the positive and negative electrode plates. In a possible implementation, the molar concent