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DE-212026000011-U1 - Battery cell, battery device and electrical device

DE212026000011U1DE 212026000011 U1DE212026000011 U1DE 212026000011U1DE-212026000011-U1

Abstract

Battery cell comprising an electrode assembly and an electrolyte, wherein the electrode assembly comprises a positive electrode and a negative electrode; wherein the positive electrode comprises a positive current collector and a positive electrode coating arranged on at least one side of the positive current collector; wherein the positive electrode coating contains a positive active material and the one-sided coating weight of the positive electrode coating is 0.36 g/1540.25 mm² to 0.43 g/1540.25 mm² ; wherein the negative electrode comprises a negative current collector and a negative electrode coating arranged on at least one side of the negative current collector, wherein the negative electrode coating comprises a negative active material and the one-sided coating weight of the negative electrode coating is 0.17 g/1540.25 mm² to 0.21 g/1540.25 mm² ; wherein the electrolyte comprises carbonate solvents, wherein the carbonate solvents contain ethyl methyl carbonate, and wherein the mass fraction of ethyl methyl carbonate is 24% to 51% based on the mass of the electrolyte.

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

Dates

Publication Date
20260513
Application Date
20260105
Priority Date
20250620

Claims (20)

  1. A battery cell comprising an electrode assembly and an electrolyte, wherein the electrode assembly comprises a positive electrode and a negative electrode; wherein the positive electrode comprises a positive current collector and a positive electrode coating arranged on at least one side of the positive current collector; wherein the positive electrode coating contains a positive active material and the one-sided coating weight of the positive electrode coating is 0.36 g/1540.25 mm² to 0.43 g/1540.25 mm² ; wherein the negative electrode comprises a negative current collector and a negative electrode coating arranged on at least one side of the negative current collector, wherein the negative electrode coating comprises a negative active material and the one-sided coating weight of the negative electrode coating is 0.17 g/1540.25 mm² to 0.21 g/1540.25 mm² ; wherein the electrolyte comprises carbonate solvents, wherein the carbonate solvents contain ethyl methyl carbonate, and wherein the mass fraction of ethyl methyl carbonate is 24% to 51% based on the mass of the electrolyte.
  2. Battery cell after Claim 1 , wherein, based on the mass of the electrolyte, the mass fraction of ethyl methyl carbonate is 30% to 44%.
  3. Battery cell after Claim 1 , wherein the carbonate solvent further comprises at least one of dimethyl carbonate and diethyl carbonate.
  4. Battery cell after Claim 3 , wherein, based on the mass of the electrolyte, the mass fraction of dimethyl carbonate and/or diethyl carbonate is 8.5% to 22%.
  5. Battery cell after Claim 4 , wherein, based on the mass of the electrolyte, the mass fraction of dimethyl carbonate and/or diethyl carbonate is 11% to 20%.
  6. Battery cell after one of the Claims 1 until 5 , where the conductivity of the electrolyte is 8 mS/cm to 14 mS/cm.
  7. Battery cell after one of the Claims 1 until 5 , where the compaction density of the positive electrode is 2.25 g/cm 3 to 2.65 g/cm 3 .
  8. Battery cell after Claim 7 , where the compaction density of the positive electrode is 2.30 g/cm 3 to 2.45 g/cm 3 .
  9. Battery cell after one of the Claims 1 until 5 , where the porosity of the positive electrode is 23% to 32%.
  10. Battery cell after one of the Claims 1 until 5 , wherein the positive active material comprises lithium-containing transition metal phosphate particles, wherein the lithium-containing transition metal phosphate particles comprise a lithium-containing transition metal phosphate matrix and a coating arranged on at least a part of the surface of the lithium-containing transition metal phosphate matrix, and wherein the coating contains carbon elements, wherein in the cumulative distribution curve of the sphericity area of the lithium-containing transition metal phosphate particles obtained from a cross-section of the positive electrode coating along the thickness direction of the positive electrode, the sphericity L A50 is 0.7 to 0.75.
  11. Battery cell after Claim 10 , where the chemical formula of the lithium-containing transition metal phosphate matrix is Li x1 A y1 Me a1 M b1 P 1-c1 X c1 Y z1 , where 0.5≤x1≤1.3, 0≤y1≤0.8, 0.9≤x1+y1≤1.3, 0.9≤a1≤1.5, 0≤b1≤0.5, 0.9≤al+bl≤1.5, 0≤c1≤0.5; 3≤z1≤5; where A comprises one or more of the elements Na, K, Mg; Me comprises one or more of the elements Mn, Fe, Co, Ni; M includes one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; X includes one or more of the elements S, Si, Cl, B, C, N, P; Y includes one or more of the elements O, F.
  12. Battery cell after Claim 10 , wherein the lithium-containing transition metal phosphate contains a Ti element, wherein, based on the mass of the lithium-containing transition metal phosphate particles, the mass fraction of the Ti element is 0.05% to 0.2%.
  13. Battery cell after Claim 10 , wherein the primary mean particle diameter of the lithium-containing transition metal phosphate is 100 nm to 2.5 µm.
  14. Battery cell after one of the Claims 1 until 5 , where the compaction density of the negative electrode is 1.3 g/cm 3 to 1.55 g/cm 3 .
  15. Battery cell after Claim 14 , where the compaction density of the negative electrode is 1.4 g/cm 3 to 1.5 g/cm 3 .
  16. Battery cell after one of the Claims 1 until 5 , where the porosity of the negative electrode is 23% to 32%.
  17. Battery cell after one of the Claims 1 until 5 , wherein the negative active material comprises graphite, wherein the volume mean particle size Dv50 of the graphite is 13 µm to 22 µm.
  18. Battery cell after Claim 17 , where the volume-average particle size Dv50 of the graphite is 14.5 µm to 20 µm.
  19. Battery cell after one of the Claims 1 until 5 , wherein the electrode assembly comprises a stacked electrode assembly.
  20. Battery cell after one of the Claims 1 until 5 , wherein the electrode assembly further comprises a separator film, wherein the separator film comprises a base membrane as well as ceramic layers arranged on both sides of the base membrane and adhesive layers arranged on the side facing away from the base membrane of at least one of the ceramic layers, wherein the adhesive layer is a continuous layer with a porous structure and the adhesive layer comprises a polyvinylidene fluoride polymer.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS The present disclosure is based on the Chinese patent application with application number 202510829022.7 , the filing date of June 20, 2025 and the application title “Battery cell, battery device and electrical device”, and claims priority of this Chinese patent application, the entire content of which is hereby incorporated into the present disclosure by reference. AREA OF INVENTION The present disclosure relates to the field of battery technology, in particular a battery cell, a battery device and an electrical device. STATE OF THE ART In recent years, with the increasing expansion of the application range of secondary battery cells, the use of secondary batteries has become ever more widespread. Secondary batteries are now commonly used in energy storage power supply systems such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, as well as in various other sectors including power tools, e-bikes, e-motorcycles, electric vehicles, and aerospace. Among secondary batteries, lithium iron phosphate batteries have received increasing attention in recent years due to their excellent safety performance. With the rapid development of lithium iron phosphate system battery cells, higher demands have also been placed on their low-temperature performance and energy density. REVELATION OF THE INVENTION The present disclosure is made with regard to the aforementioned tasks, and its purpose is to provide a battery cell, a battery device and an electrical device, wherein the battery cell provided by the present disclosure can take into account both low-temperature performance and energy density. To achieve the aforementioned purpose, the present disclosure provides, in a first aspect, a battery cell comprising an electrode assembly and an electrolyte; the electrode assembly comprising a positive electrode and a negative electrode; the positive electrode comprising a positive current collector and a positive electrode coating arranged on at least one side of the positive current collector, wherein the positive electrode coating comprises a positive active material and the one-sided coating weight of the positive electrode coating is 0.36 g/1540.25 mm² to 0.43 g/1540.25 mm² ; the negative electrode comprising a negative current collector and a negative electrode coating arranged on at least one side of the negative current collector, wherein the negative electrode coating comprises a negative active material and the one-sided coating weight of the negative electrode coating is 0.17 g/1540.25 mm² to 0.21 g/1540.25 mm² ; The electrolyte comprises a carbonate solvent, wherein the carbonate solvent comprises ethyl methyl carbonate, and the mass fraction of the ethyl methyl carbonate is 24% to 51% based on the mass of the electrolyte. In the present disclosure, the fact that the one-sided coating weight of the positive electrode coating is 0.36 g/1540.25 mm² to 0.43 g/1540.25 mm² and the one-sided coating weight of the negative electrode coating is 0.17 g/1540.25 mm² to 0.21 g/1540.25 mm² results in a high energy density for the battery cell. Furthermore, the selection of an electrolyte with a mass fraction of ethyl methyl carbonate of 24% to 51% promotes the movement of lithium ions at low temperatures, thereby improving the low-temperature performance of the battery cell. In some embodiments, the mass fraction of ethyl methyl carbonate is 30% to 44%, based on the mass of the electrolyte. This is advantageous for further consideration of the low-temperature performance and the energy density of the battery cell. In some embodiments, the carbonate solvent further comprises at least one of dimethyl carbonate and one of diethyl carbonate. Dimethyl carbonate and diethyl carbonate have a low viscosity; the addition of dimethyl carbonate and/or diethyl carbonate is advantageous for reducing the viscosity of the electrolyte and for increasing the conductivity and wettability of the electrolyte, thereby improving the low-temperature performance of the battery cell. In some embodiments, the mass fraction of dimethyl carbonate and/or diethyl carbonate is 8.5% to 22%, based on the mass of the electrolyte. This is advantageous for further improving the low-temperature performance of the battery cell. In some embodiments, the mass fraction of dimethyl carbonate and/or diethyl carbonate is 11% to 20%, based on the mass of the electrolyte. This is advantageous for further improving the low-temperature performance of the battery cell. In some embodiments, the electrolyte has a conductivity of 8 mS/cm to 14 mS/cm. This is advantageous for reducing the internal resistance of the battery cell, for reducing energy losses caused by resistance during charging and discharging, and for extending the battery cell's service life. In some embodiments, the compaction density of the positive electrode is 2.25 g/ cm³ to 2.65 g/ cm³ . This is advantageous so that the batte