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DE-202025004163-U1 - Secondary battery and power-consuming device

DE202025004163U1DE 202025004163 U1DE202025004163 U1DE 202025004163U1DE-202025004163-U1

Abstract

Secondary battery, characterized in that it comprises a cathode foil, an anode foil and an electrolyte solution, wherein the cathode foil comprises a cathode collector and a cathode film layer containing an active cathode material arranged on at least one side of the cathode collector, wherein the active cathode material comprises a core of a lithium iron phosphate material and a carbon shell layer that at least partially encloses the outer surface of the core, wherein the ratio I d /I g of the peak intensity I d of the D-peak with a Raman shift in the range of 1350 ± 50 cm -1 to the peak intensity I g of the G-peaks with a Raman shift in the range of 1580 ± 50 cm -1 in the Raman spectrum of the active cathode material is 0.2 to 1.5, wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein, when the secondary battery is in a state of charge of 100% or the voltage of the secondary battery is 3.65 V, the heat dissipation Q of the anode film layer in the electrolyte solution satisfies 250 J/g ≤ Q ≤ 600 J/g.

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

Dates

Publication Date
20260513
Application Date
20250807
Priority Date
20250807

Claims (10)

  1. A secondary battery, characterized in that it comprises a cathode foil, an anode foil, and an electrolyte solution, wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector and containing an active cathode material, wherein the active cathode material comprises a core of a lithium iron phosphate material and a carbon shell layer that at least partially encloses the outer surface of the core, wherein the ratio I <sub>d</sub> /I <sub>g </sub> of the peak intensity I <sub>d</sub> of the D-peak with a Raman shift in the range of 1350 ± 50 cm <sup>-1 </sup> to the peak intensity I <sub>g</sub> of the G-peaks with a Raman shift in the range of 1580 ± 50 cm<sup> -1</sup> in the Raman spectrum of the active cathode material is 0.2 to 1.5, wherein the anode foil comprises an anode collector and a cathode film layer arranged on at least one side of the The anode film layer is arranged in the anode collector, wherein, when the secondary battery is at a state of charge of 100% or the voltage of the secondary battery is 3.65 V, the heat dissipation Q of the anode film layer in the electrolyte solution satisfies 250 J/g ≤ Q ≤ 600 J/g.
  2. Secondary battery after Claim 1 , characterized in that the I d /I g ratio of the active cathode material is 0.9 to 1.3.
  3. Secondary battery after Claim 1 , characterized in that the I d /I g ratio of the active cathode material is 0.3 to 1.1.
  4. Secondary battery after one of the Claims 1 until 3 , characterized in that the I d /I g ratio of the active cathode material is 0.8 to 1.2.
  5. Secondary battery after one of the Claims 1 until 4 , characterized in that the carbon shell layer comprises amorphous carbon and graphene.
  6. Secondary battery after one of the Claims 1 until 5 , characterized in that the powder resistance of the active cathode material is 0 to 30 Ω·cm at a pressure of 16 MPa.
  7. Secondary battery after one of the Claims 1 until 6 , characterized in that the lithium iron phosphate material comprises a material represented by the formula: LixFeyMzPO 4 , where 0.95<x<1.05, 0.96<y≤1 and 0≤z<0.04 apply, where M comprises one or more of the elements Ti, V, Mg, Zr, Y.
  8. Secondary battery after Claim 7 , characterized in that the content of the M element is 0.02% to 0.3% in relation to the total weight of the active cathode material.
  9. Secondary battery after Claim 7 , characterized in that the content of the M element is 0.03% to 0.1% in relation to the total weight of the active cathode material.
  10. Power-consuming device, characterized in that it has a secondary battery after one of the Claims 1 until 9 includes.

Description

CROSS-REFERENCE TO RELATED REGISTRATION The present application claims priority of Chinese patent application no. 202411389200.0 entitled “Secondary battery and power-consuming device”, which was filed on September 30, 2024. The entire contents of this Chinese patent application are hereby incorporated by reference. TECHNICAL AREA The present application relates to the technical field of secondary batteries, in particular a secondary battery and a power-consuming device. STATE OF THE ART In recent years, secondary batteries have become increasingly widespread in energy storage systems for hydropower, thermal, wind and solar power plants, as well as in numerous other areas, including power tools, e-bikes, e-motorcycles, electric vehicles, military equipment and aerospace. However, existing technologies struggle to reconcile both energy efficiency and overcharge protection in secondary batteries. Therefore, there is a need for a secondary battery that combines high energy efficiency with improved overcharge protection. CONTENT OF THE PRESENT INVENTION The present application addresses the aforementioned problems and aims to provide a secondary battery and a power-consuming device that combine high energy efficiency with good overcharge protection. The inventors have discovered that the technical solutions proposed here achieve the stated goals. A first aspect of the present application provides a secondary battery comprising a cathode foil, an anode foil and an electrolyte solution, wherein the cathode foil comprises a cathode collector and a cathode film layer containing an active cathode material arranged on at least one side of the cathode collector, wherein the active cathode material comprises a core of a lithium iron phosphate material and a carbon shell layer that at least partially encloses the outer surface of the core, wherein the ratio I <sub>d</sub> /I <sub>g </sub> of the peak intensity I<sub>d</sub> of the D-peak with a Raman shift in the range of 1350 ± 50 cm <sup>-1</sup> to the peak intensity I<sub>g</sub> of the G-peaks with a Raman shift in the range of 1580 ± 50 cm<sup>-1</sup> in the Raman spectrum of the active cathode material is 0.2 to 1.5, wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein, when the secondary battery is in a state of charge of 100% or the voltage of the secondary battery is 3.65 V, the heat dissipation Q of the anode film layer in the electrolyte solution 250 J/g ≤ Q ≤ 600 J/g is met. The secondary battery of the present application exhibits both high energy efficiency and improved overcharge protection. In each embodiment, the I d /I g ratio of the active cathode material is 0.9 to 1.3. If the I <sub>d</sub> /I<sub>g</sub> ratio of the active cathode material is 0.9-1.3, the secondary battery of the present application exhibits high energy efficiency and good cycle performance. In each embodiment, the I d /I g ratio of the active cathode material is 0.3 to 1.1. If the I <sub>d</sub> /I<sub>g</sub> ratio of the active cathode material is 0.3-1.1, the secondary battery of the present application exhibits a low expansion force. In each embodiment, the I d /I g ratio of the active cathode material is 0.8 to 1.2. If the I <sub>d</sub> /I<sub>g</sub> ratio of the active cathode material is 0.8-1.2, the secondary battery of the present application exhibits high energy efficiency, good cycle performance, and low expansion force. In each embodiment, the carbon shell layer comprises amorphous carbon and graphene. If the carbon shell layer comprises amorphous carbon and graphene, the secondary battery of the present application exhibits high energy efficiency and good cycle performance. In each embodiment, the powder resistance of the active cathode material at a pressure of 16 MPa is 0 to 30 Ω·cm. If the powder resistance of the active cathode material is 0 to 30 Ω·cm at a pressure of 16 MPa, the secondary battery of the present application exhibits high energy efficiency and good cycle performance. In each embodiment, the lithium iron phosphate material comprises a material represented by the formula: LixFeyMzPO 4 , where 0.95<x<1.05, 0.96<y≤1 and 0≤z<0.04 hold true, where M comprises one or more of the elements Ti, V, Mg, Zr, Y. In each embodiment, the content of the M element is 0.02% to 0.3%, based on the total weight of the active cathode material. If the content of the M-element is 0.02% to 0.3%, the secondary battery of the present application exhibits high energy efficiency and good cycle performance. In each embodiment, the content of the M element is 0.03% to 0.1%, based on the total weight of the active cathode material. If the content of the M-element is between 0.03% and 0.1%, the secondary battery of the present application exhibits high energy efficiency and good cycle performance. A second aspect of the present application provides a power-consuming device comprising a second