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DE-212025000092-U1 - Battery cell, battery device and power-consuming device

DE212025000092U1DE 212025000092 U1DE212025000092 U1DE 212025000092U1DE-212025000092-U1

Abstract

Battery cell, including: a bowl; and an electrode assembly located in the dish, wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, the separating film being located between the cathode foil and the anode foil; where the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises a first anode film layer facing away from the anode collector and a second anode film layer facing the anode collector, and wherein the first anode film layer comprises a first active anode material, while the second anode film layer comprises a second active anode material; and wherein the first active anode material comprises a first carbon-based material and a first silicon-based material; and wherein the second active anode material comprises a second carbon-based material, and wherein the second anode film layer does not contain a Si element, or alternatively, the second active anode material comprises a second carbon-based material and a second silicon-based material, and wherein the mass fraction of the Si element in the first anode film layer is greater than that in the second anode film layer; and wherein the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0% and less than or equal to 20%.

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

Dates

Publication Date
20260513
Application Date
20250710
Priority Date
20250710

Claims (20)

  1. Battery cell comprising: a shell; and an electrode assembly located in the shell, the electrode assembly comprising a cathode foil, an anode foil, and a separating film, the separating film being located between the cathode foil and the anode foil; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, and wherein the anode film layer comprises a first anode film layer facing away from the anode collector and a second anode film layer facing the anode collector, and wherein the first anode film layer comprises a first active anode material, while the second anode film layer comprises a second active anode material; and wherein the first active anode material comprises a first carbon-based material and a first silicon-based material; and wherein the second active anode material comprises a second carbon-based material, and wherein the second anode film layer contains no silicon element, or alternatively, the second active anode material comprises a second carbon-based material and a second silicon-based material, and wherein the mass fraction of the silicon element in the first anode film layer is greater than that in the second anode film layer; and wherein the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0% and less than or equal to 20%.
  2. Battery cell after Claim 1 , where the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0% and less than or equal to 12%.
  3. Battery cell after Claim 1 or 2 , where the concentration of the second silicon-based material in the second anode film layer is greater than or equal to 0% and less than or equal to 10%.
  4. Battery cell after Claim 3 , wherein the concentration of the second silicon-based material in the second anode film layer is greater than or equal to 0% and less than or equal to 5%.
  5. Battery cell after one of the Claims 1 until 4 , wherein the concentration of the first silicon-based material in the first anode film layer is greater than the concentration of the second silicon-based material in the second anode film layer.
  6. Battery cell after one of the Claims 1 until 5 , wherein the mass fraction of the Si element in the first anode film layer is 1% to 11%; and/or wherein the mass fraction of the Si element in the second anode film layer is 0% to 5%.
  7. Battery cell after one of the Claims 1 until 6 , where the mass fraction of the Si element in the anode film layer is 1% to 10%.
  8. Battery cell after Claim 7 , where the mass fraction of the Si element in the anode film layer is 1% to 5%.
  9. Battery cell after one of the Claims 1 until 8 , wherein in the first anode film layer the area fraction of the silicon-based material with a particle size of more than 1 µm is 90% to 100% in the silicon-based material; wherein in the second anode film layer the area fraction of the silicon-based material with a particle size of more than 1 µm is 90% to 100% in the silicon-based material.
  10. Battery cell after one of the Claims 1 until 9 , wherein the anode film layer satisfies one or more of the following conditions (1) to (8): (1) the first silicon-based material comprises one or more of elemental silicon, silicon-carbon materials, silicon oxides, silicon nitrides, and silicon alloy materials; (2) the average particle size of the second silicon-based material is 2 µm to 10 µm; (3) the first carbon-based material comprises one or more of natural graphite, synthetic graphite, soft carbon, hard carbon, and mesophased carbon microspheres; (4) the average particle size of the first carbon-based material is 14 µm to 20 µm; (5) the second active anode material comprises a second silicon-based material comprising one or more of elemental silicon, silicon-carbon materials, silicon oxides, silicon nitrides, and silicon alloy materials; (6) the second active anode material comprises a second silicon-based material, wherein the average particle size of the second silicon-based material is 2 µm to 10 µm; (7) the second carbon-based material comprises one or more microspheres of natural graphite, synthetic graphite, soft carbon, hard carbon and mesophase carbon; (8) the average particle size of the second carbon-based material is 14 µm to 20 µm.
  11. Battery cell after one of the Claims 1 until 10 , wherein the anode film layer satisfies one or more of the following conditions (1) to (4): (1) the first silicon-based material comprises one or more of silicon-carbon materials and premagnesium siloxides; (2) the first carbon-based material comprises one or more of natural graphite and synthetic graphite; (3) the second active anode material comprises a second silicon-based material, wherein the second silicon-based material comprises one or more of silicon-carbon materials and premagnesium siloxanes; (4) the second carbon-based material comprises one or more of natural graphite and synthetic graphite.
  12. Battery cell after one of the Claims 1 until 11 , where the volumetric particle size distribution Dv50 of the first active anode material is smaller than the volumetric particle size distribution Dv50 of the second active anode material.
  13. Battery cell after one of the Claims 1 until 12 , where the compression density of the anode film layer is 1.4 g/cm 3 to 1.6 g/cm 3 .
  14. Battery cell after one of the Claims 1 until 13 , wherein the thickness of the anode collector is 5 µm to 10 µm; and/or wherein the strain rate in the tab area of the anode collector is 10% to 20%.
  15. Battery cell after one of the Claims 1 until 14 , where the thickness H1 of the anode collector in the tab area and the thickness H2 of the anode collector in the middle area satisfy the condition that (H1-H2)/H1 is greater than 0 and less than or equal to 10%.
  16. Battery cell after one of the Claims 1 until 15 , wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises a lithium transition metal oxide.
  17. Battery cell after Claim 16 , where the volumetric particle size distribution Dv50 of the active cathode material is 2 µm to 7 µm.
  18. Battery cell after Claim 16 or 17 , wherein the lithium transition metal oxide comprises a lithium transition metal oxide with a single-crystal morphology, wherein the proportion of the total area of the lithium transition metal oxide with a single-crystal morphology in the total area of the active cathode material is 60% to 100%.
  19. Battery cell after one of the Claims 16 until 18 , wherein the lithium transition metal oxide comprises Ni element, wherein the molar fraction of the Ni element among the transition metal elements in the lithium transition metal oxide exceeds 80%.
  20. Battery cell after one of the Claims 16 until 19 , wherein the lithium transition metal oxide comprises Ni and Co elements, wherein the Co content in the surface region of the lithium transition metal oxide is higher than the Co content in the core region of the lithium transition metal oxide; or wherein the lithium transition metal oxide comprises Ni and Mn elements, wherein the Mn content in the surface region of the lithium transition metal oxide is higher than the Mn content in the core region of the lithium transition metal oxide; or wherein the lithium transition metal oxide comprises Ni, Co and Mn elements, wherein the Co content in the surface region of the lithium transition metal oxide is higher than the Co content in the core region of the lithium transition metal oxide, while the Mn content in the surface region of the lithium transition metal oxide is lower than the Mn content in the core region of the lithium transition metal oxide, wherein the surface region of the lithium transition metal oxide is defined as a region extending radially inwards by 100 nm from the outermost surface of the particle, while the core region of the lithium transition metal oxide is defined as a region extending radially outwards by 300 nm from the center of the particle.

Description

TECHNICAL AREA The present application relates to a battery cell, a battery device and a power-consuming device. STATE OF THE ART In recent years, with the widespread adoption of lithium-ion battery cells, the energy density of existing lithium-ion battery cells using graphite as the active anode material has become insufficient to meet ever-increasing technical demands. Silicon-based materials have emerged as promising candidates for novel active anode materials due to their moderate lithium intercalation potential and high theoretical specific capacity. However, these materials suffer from significant volume expansion during cyclic charge and discharge cycles and exhibit difficulties in forming a stable solid electrolyte interphase (SEI) film, leading to rapid capacity loss in lithium-ion battery cells. CONTENT OF THE PRESENT INVENTION The present disclosure provides a battery cell, a battery device and a power-consuming device, wherein the battery cell achieves both a high energy density and excellent cycle performance. In a first aspect, the present disclosure provides a battery cell comprising a shell and an electrode assembly, wherein the electrode assembly is located in the shell, and wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, and wherein the separating film is located between the cathode foil and the anode foil, and wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, and wherein the anode film layer comprises a first anode film layer facing away from the anode collector and a second anode film layer facing the anode collector, and wherein the first anode film layer comprises a first active anode material, while the second anode film layer comprises a second active anode material, and wherein the first active anode material comprises a first carbon-based material and a first silicon-based material; and wherein the second active anode material comprises a second carbon-based material, and wherein the second anode film layer does not contain any Si element, or alternatively, the second active anode material comprises a second carbon-based material and a second silicon-based material, and wherein the mass fraction of the Si element in the first anode film layer is greater than that in the second anode film layer; and wherein the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0% and less than or equal to 20%. The first anode film layer is located in the surface region, while the second anode film layer is located in the bottom region. Maintaining a high mass fraction of the silicon element in the surface region helps to mitigate problems with lithium precipitation on the anode. The second anode film layer is located in the bottom region. By keeping the bottom region free of silicon or maintaining a low mass fraction of silicon within it, this configuration reduces damage to the overall conductive network of the anode film layer caused by the volume expansion of the silicon-based material in the bottom region. Consequently, this improves the cycle stability of the battery cell. In the present disclosure, the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0 and less than or equal to 20%. This ensures a more uniform distribution of the first silicon-based material in the surface region. This mitigates problems with stress concentrations caused by volume expansion and contraction during the charge-discharge cycle of the first silicon-based material, thereby reducing the contact forces between the first silicon-based material and the anode collector. Consequently, the anode collector maintains its structural stability throughout the entire charge-discharge cycle, preventing anode collector fractures and battery cell degradation in the late stages of the cycle. Therefore, the present disclosure enables the battery cell to achieve both high energy density and extended cycle life by adapting the anode structure. In some embodiments, the concentration of the first silicon-based material in the first anode film layer is greater than or equal to 0% and less than or equal to 12%. In some embodiments, the concentration of the second silicon-based material in the second anode film layer is greater than or equal to 0% and less than or equal to 10%, or optionally greater than or equal to 0% and less than or equal to 5%. This further improves the cycle life of the battery cell. In some embodiments, the concentration of the first silicon-based material in the first anode film layer is higher than the concentration of the second silicon-based material in the second anode film layer. This further improves the cycle life of the battery cell. In some embodiments, the mass fraction of the Si element in the first anode film layer is 1% to 11%. In some embodiments, the mass fraction