Battery cell, battery device, and electric device

Abstract

The present application provides a battery cell, a battery device, and an electric device. The battery cell of the present application comprises an electrode assembly; the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet; the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer located on at least one side of the negative electrode current collector, the negative electrode active layer comprises a negative electrode material, the negative electrode material comprises a negative electrode active material, and the negative electrode active material includes graphite; the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer located on at least one side of the positive electrode current collector, the positive electrode active layer comprises a positive electrode material, the positive electrode material comprises a positive electrode active material, and the positive electrode active material includes a lithium iron phosphate material and a lithium manganese iron phosphate material; the surface density of the positive electrode active layer is 200-370 mg / 1540.25 mm2; and when the battery cell is in a 100% SOC state, the compaction density of the positive electrode active layer is 2.27-2.67 g / cm3. The battery cell of the present application has the advantages of low costs, high energy density, and long cycle life.

Description

Battery cell, battery device, and electric device

[0001] This application is based on Chinese Patent Application No. 202411263615.3, filed on September 10, 2024, and Chinese Patent Application No. 202411087232.5, filed on August 8, 2024, for which priority is claimed, and the contents of all of the aforementioned applications are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a battery cell, a battery device, and an electric device. BACKGROUND

[0003] In recent years, with the application range of batteries becoming more and more extensive, batteries are widely used in energy storage power systems such as hydroelectric, thermal, wind, and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. Due to the great development of batteries, higher requirements are put forward for their cycle performance and energy density. SUMMARY

[0004] The present application is made in view of the above-mentioned problems, and aims to provide a battery cell, a battery device, and an electric device. The battery cell of the present application improves the cycle performance and energy density while taking into account low cost.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a battery cell, comprising an electrode assembly, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet, and a separator film located between the positive electrode sheet and the negative electrode sheet;

[0006] The negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer located on at least one side of the negative electrode current collector, the negative electrode active layer comprising a negative electrode material, the negative electrode material comprising a negative electrode active material, the negative electrode active material comprising graphite;

[0007] The positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer located on at least one side of the positive electrode current collector, the positive electrode active layer comprising a positive electrode material, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising a lithium iron phosphate material and a lithium manganese iron phosphate material;

[0008] The face density of the positive electrode active layer is 200-370 mg / 1540.25 mm 2 , and the compaction density of the positive electrode active layer is 2.27-2.67 g / cm 3 .

[0009] Thus, when the lithium manganese iron phosphate material and the lithium iron phosphate material are mixed in the application, the surface density of the positive active layer of the battery monomer in the 100% SOC state is limited to 200-370 mg / 1540.25 mm 2 , and the compaction density of the positive active layer of the battery monomer in the 100% SOC state is limited to 2.27-2.67 g / cm 3 , and a battery monomer with low cost, high energy density and high cycle life is developed.

[0010] In any embodiment, the surface density of the positive active layer of the battery monomer in the 100% SOC state is 240-340 mg / 1540.25 mm 2 . Thus, the cycle performance and energy density of the battery monomer are improved at the same time.

[0011] In any embodiment, the compaction density of the positive active layer of the battery monomer in the 100% SOC state is 2.40-2.67 g / cm 3 . Thus, the cycle performance and energy density of the battery monomer are improved at the same time.

[0012] In any embodiment, the compaction density of the negative active layer of the battery monomer in the 100% SOC state is 1.04-1.48 g / cm 3 , and can be 1.23-1.42 g / cm 3 . Thus, by limiting the compaction density of the negative active layer of the battery monomer in the 100% SOC state within the above range, the energy density of the battery monomer is improved while the cycle performance of the battery monomer is guaranteed.

[0013] In any embodiment, the surface density of the negative active layer of the battery monomer in the 100% SOC state is 79-170 mg / 1540.25 mm 2 or 100-155 mg / 1540.25 mm 2 . Thus, the energy density of the battery monomer is further improved.

[0014] In any embodiment, the mass percentage of manganese in the positive active material is 2.1%-25%. Thus, by limiting the mass percentage of manganese in the positive active material within the above range, the energy density of the battery monomer is improved while the cycle performance of the battery monomer is guaranteed.

[0015] In any embodiment, the positive electrode active material further comprises one or more elements of 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, Hf, Ni, Co, Ru, Ag, Pb.

[0016] In any embodiment, the powder compaction density of the positive electrode material at 30000 N is 2.3-2.7 g / cm 3 , optionally 2.43-2.6 g / cm 3 .

[0017] In any embodiment, the BET specific surface area of the positive electrode material is 7.5-16 m 2 / g.

[0018] In any embodiment, the volume average particle size Dv50 of the positive electrode material is 0.35-2 μm, optionally 0.35-1.2 μm.

[0019] In any embodiment, the mass ratio of the lithium iron phosphate material to the lithium manganese iron phosphate material is 1:9-9:1, optionally 3:7-7:3.

[0020] In any embodiment, the positive electrode active material further comprises carbon; and / or,

[0021] Optionally, the mass percentage of the carbon is 1%-3% based on the mass of the positive electrode material.

[0022] Thereby, the conductivity of the positive electrode active material is further improved.

[0023] In any embodiment, the positive electrode sheet further comprises a positive electrode conductive layer, the positive electrode conductive layer being arranged between the positive electrode current collector and the positive electrode active layer.

[0024] In any embodiment, the thickness of the positive electrode conductive layer is 0.5-2 μm.

[0025] In any embodiment, the positive electrode conductive layer comprises one or more of a positive electrode conductive agent, a positive electrode binder.

[0026] In any embodiment, the battery cell comprises one or more of:

[0027] The positive electrode conductive agent comprises one or more of super conductive carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers;

[0028] The positive electrode conductive agent at least comprises super conductive carbon and carbon nanotubes.

[0029] The positive electrode binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, a polyacrylic acid, and a fluorine-containing acrylic ester resin.

[0030] In any embodiment, the mass percentage content of the positive electrode conductive agent is 30%-50% based on the mass of the positive electrode conductive layer; and / or,

[0031] The mass percentage content of the positive electrode binder is 50%-70% based on the mass of the positive electrode conductive layer.

[0032] In any embodiment, the chemical formula of the lithium iron phosphate material is Li x Fe (1-s) M s P y O z , wherein x is greater than or equal to 0.5 and less than or equal to 1.3, s is greater than or equal to 0 and less than 1, y is greater than or equal to 0.5 and less than or equal to 1.3, z is greater than or equal to 3 and less than or equal to 5, M comprises one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb; and / or,

[0033] The chemical formula of the lithium manganese iron phosphate material is Li x Fe (1-t-s) Mn t M s P y O z , wherein x is greater than or equal to 0.5 and less than or equal to 1.3, t is greater than 0 and less than 1, s is greater than or equal to 0 and less than 1, 1-t-s is greater than 0 and less than 1, y is greater than or equal to 0.5 and less than or equal to 1.3, z is greater than or equal to 3 and less than or equal to 5, M comprises one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb.

[0034] In any embodiment, the positive active layer further comprises a lithium supplement agent, the lithium supplement agent comprising one or more of lithium nickel cobalt manganese oxide, lithium ferrite, lithium nickelate, lithium cobaltate, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium manganite, lithium tartrate, lithium citrate, lithium oxide, lithium fluoride, lithium sulfide, lithium nitride;

[0035] Optionally, the lithium ferrite in the lithium supplement agent is lithium-rich lithium ferrite.

[0036] Optionally, the lithium nickelate in the lithium supplement agent is lithium-rich lithium nickelate.

[0037] In any embodiment, the negative electrode sheet further comprises a negative electrode conductive layer, the negative electrode conductive layer being arranged between the negative electrode current collector and the negative electrode active layer.

[0038] In any embodiment, the negative electrode conductive layer has a thickness of 0.5-2 μm.

[0039] In any embodiment, the negative electrode conductive layer comprises one or more of a negative electrode conductive agent, a negative electrode binder.

[0040] In any embodiment, the negative electrode conductive agent comprises one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers; and / or,

[0041] The negative electrode binder comprises one or more of butadiene styrene rubber, water-soluble unsaturated resin, water-based acrylic resin, polyvinyl alcohol, sodium alginate, carboxymethyl chitosan.

[0042] In any embodiment, the mass percentage content of the negative electrode conductive agent is 20%-40% based on the mass of the negative electrode conductive layer; and / or,

[0043] The mass percentage content of the negative electrode binder is 60%-80% based on the mass of the negative electrode conductive layer.

[0044] In any embodiment, the negative electrode active layer has a single-layer or multi-layer structure, and the volume average particle size Dv50 of the negative electrode active material in the negative electrode active layer is 7.5-19.5 μm.

[0045] In any embodiment, the negative electrode active layer has a single-layer structure, and the volume average particle size Dv50 of the negative electrode active material is 8.0-17.5 μm.

[0046] In any embodiment, the negative electrode active layer comprises a first negative electrode active layer close to the negative electrode current collector and a second negative electrode active layer arranged on the first negative electrode active layer.

[0047] In any embodiment, the thickness ratio of the second negative electrode active layer to the first negative electrode active layer is 2:8-8:2.

[0048] In any embodiment, the volume average particle size Dv50 of the negative electrode active material in the first negative electrode active layer is 7.5-19.5 μm, optionally 12.5-18.5 μm.

[0049] In any embodiment, the volume average particle size Dv50 of the negative electrode active material in the second negative electrode active layer is 7.5-19.5 μm, optionally 7.5-15.5 μm.

[0050] In any embodiment, the volume average particle size Dv50 of the negative electrode active material in the second negative electrode active layer is less than the volume average particle size Dv50 of the negative electrode active material in the first negative electrode active layer. Thereby, it is beneficial to improve the discharge power of the battery cell, while increasing the energy density of the battery cell and reducing the cost.

[0051] In any embodiment, the graphite in the first negative electrode active layer and the second negative electrode active layer is independently selected from one or more of natural graphite, composite graphite.

[0052] In any embodiment, the composite graphite comprises a body and a coating layer coated on the surface of the body; the body comprises artificial graphite, and the coating layer comprises amorphous carbon.

[0053] In any embodiment, the composite graphite comprises secondary particles.

[0054] In any embodiment, the powder resistivity of the composite graphite at 8 MPa is 0.01-0.04 Ω·cm.

[0055] In any embodiment, the powder compaction density of the composite graphite at a pressure of 20,000 N is 1.5-1.85 g / cm 3 , optionally 1.55-1.75 g / cm 3 .

[0056] In any embodiment, the charge gram capacity of the negative electrode material at 0.1C rate is 350-550 mAh / g.

[0057] In any embodiment, the negative electrode active material further comprises a silicon material.

[0058] In any embodiment, the silicon material comprises one or more of silicon oxide compounds, silicon carbon compounds; and / or,

[0059] The mass percentage of the silicon element is 0.3%-10%, and optionally 1%-6%, based on the mass of the negative electrode material.

[0060] In any embodiment, the battery cell further comprises an electrolyte, and the electrolyte has an electrical conductivity of 10-20 mS / cm, and optionally 12-17 mS / cm, at room temperature.

[0061] In any embodiment, the battery cell further comprises a separator film, and the separator film comprises a porous base film and a functional film layer arranged on at least one side of the porous base film.

[0062] In any embodiment, the thickness of the porous base film is 5-7 μm; and / or,

[0063] The porosity of the porous base film is 20%-70% or 30%-50%.

[0064] In any embodiment, the functional film layer comprises a first functional film layer and a second functional film layer arranged on two sides of the porous base film, respectively, the first functional film layer comprises inorganic material particles, and the second functional film layer comprises composite particles, and the composite particles comprise non-fluoropolymer particles and inorganic material particles attached to the surface of the non-fluoropolymer particles or located in the non-fluoropolymer particles.

[0065] In any embodiment, the thickness of the positive electrode current collector is 9-17 μm; and / or,

[0066] The thickness of the negative electrode current collector is 4.5-8 μm.

[0067] In any embodiment, the injection coefficient of the battery cell is 2.4-3.1 g / Ah.

[0068] In any embodiment, the volumetric energy density of the battery cell is 400-550 Wh / L or 430-500 Wh / L.

[0069] The second aspect of the present application further provides a battery device comprising the battery cell of the first aspect of the present application; and the battery device comprises a battery module, a battery pack or an energy storage device.

[0070] The third aspect of the present application further provides a power utilization device comprising the battery cell of the first aspect of the present application or the battery device of the second aspect of the present application.

[0071] The present application further relates to the following aspects:

[0072] 1. A battery cell comprising an electrode assembly, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet and a separator film located between the positive electrode sheet and the negative electrode sheet.

[0073] The negative electrode tab includes a negative current collector and a negative active layer located on at least one side of the negative current collector, the negative active layer including a negative material, the negative material including a negative active material, the negative active material comprising graphite;

[0074] The positive electrode tab includes a positive current collector and a positive active layer located on at least one side of the positive current collector, the positive active layer including a positive material, the positive material including a positive active material, the positive active material comprising a lithium iron phosphate material and a lithium manganese iron phosphate material;

[0075] The positive active layer has an area density of 200-370 mg / 1540.25 mm 2 ; and a compaction density of 2.45-2.80 g / cm 3 ; under a full charge state of the battery, wherein the full charge state is a state reached by charging the battery at 0.33 C to a voltage of 4.1 V and then charging the battery at 4.1 V to less than 0.05 C at 25 °C.

[0076] 2. The battery cell according to the first aspect, wherein the positive active layer has an area density of 240-340 mg / 1540.25 mm 2 .

[0077] 3. The battery cell according to the first or second aspect, wherein the positive active layer has a compaction density of 2.40-2.7 g / cm 3 .

[0078] 4. The battery cell according to any one of the first to third aspects, wherein the negative active layer has a compaction density of 1.04-1.48 g / cm 3 or 1.23-1.42 g / cm 3 ; under a full charge state of the battery.

[0079] 5. The battery cell according to any one of the first to fourth aspects, wherein the negative active layer has an area density of 90-170 mg / 1540.25 mm 2 or 100-155 mg / 1540.25 mm 2 .

[0080] 6. The battery cell according to any one of the first to fifth aspects, wherein the negative active layer has a compaction density of 1.50-1.75 g / cm 3 or 1.55-1.65 g / cm 3 ; after cold pressing.

[0081] 7. The battery cell according to any one of the first to sixth aspects, wherein the mass percentage of manganese element is 2.1%-25% based on the mass of the positive material.

[0082] 8. The battery cell according to any one of aspects 1 to 7, wherein the positive active material further comprises one or more elements selected from the group consisting of 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, Hf, Ni, Co, Ru, Ag, Pb.

[0083] 9. The battery cell according to any one of aspects 1 to 8, wherein the positive active material has a powder compaction density of 2.3-2.7 g / cm3 or 2.43-2.6 g / cm3 at 30000 N. 3 . 3

[0084] 10. The battery cell according to any one of aspects 1 to 9, wherein the positive active material has a powder resistivity of 1-80 Ω-cm or 1-60 Ω-cm at 12 MPa.

[0085] 11. The battery cell according to any one of aspects 1 to 10, wherein the positive active material has a specific surface area of 7.5-16 m2 / g. 2

[0086] 12. The battery cell according to any one of aspects 1 to 11, wherein the positive active material has a volume average particle size Dv50 of 0.85-2 pm or 0.35-1.2 pm.

[0087] 13. The battery cell according to any one of aspects 1 to 12, wherein the mass ratio of the lithium iron phosphate material to the lithium manganese iron phosphate material is 1:9-9:1 or 3:7-7:3.

[0088] 14. The battery cell according to any one of aspects 1 to 13, wherein the positive active material further comprises carbon; and / or,

[0089] the mass percentage of the carbon is 1%-3% based on the mass of the positive active material.

[0090] 15. The battery cell according to any one of aspects 1 to 14, wherein the positive electrode sheet further comprises a positive conductive layer disposed between the positive current collector and the positive active layer.

[0091] 16. The battery cell according to aspect 15, wherein the positive conductive layer has a thickness of 0.5-2 pm.

[0092] 17. The battery cell according to aspect 15 or 16, wherein the positive conductive layer comprises one or more of a positive conductive agent, a positive binder.

[0093] 18. The battery cell according to aspect 17, comprising one or more of: ​​

[0094] The positive electrode conductive agent includes one or more of super conductive carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers;

[0095] The positive electrode conductive agent includes at least super conductive carbon and carbon nanotubes.

[0096] The positive electrode binder includes one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, and fluorine-containing acrylic ester-based resin.

[0097] 19. The battery cell based on the 17th or 18th aspect, the mass percentage of the positive electrode conductive agent is 30%-50% based on the mass of the positive electrode conductive layer; and / or,

[0098] The mass percentage of the positive electrode binder is 50%-70% based on the mass of the positive electrode conductive layer.

[0099] 20. The battery cell based on any one of the 1st to 19th aspect,

[0100] The chemical formula of the lithium iron phosphate material and the lithium manganese iron phosphate material is independently Li x Fe (1-t-s) Mn t M s P y O z , wherein each of x is independently greater than or equal to 0.5 and less than or equal to 1.3, each of t is independently greater than or equal to 0 and less than or equal to 1, each of s is independently greater than or equal to 0 and less than 1, each of y is independently greater than or equal to 0.5 and less than or equal to 1.3, each of z is independently greater than or equal to 3 and less than or equal to 5, and each of M independently includes one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb; and / or,

[0101] The lithium iron phosphate material and the lithium manganese iron phosphate material are each independently olivine structure.

[0102] 21. The battery cell according to any one of aspects 1 to 20, wherein the positive active layer further comprises a lithium supplement agent, the lithium supplement agent comprising one or more of lithium nickel cobalt manganese oxide, lithium ferrite, lithium nickelate, lithium cobaltate, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium metavanadate, lithium tartrate, lithium citrate, lithium oxide, lithium fluoride, lithium sulfide, lithium nitride; and / or,

[0103] the lithium ferrite in the lithium supplement agent is lithium-rich lithium ferrite; and / or,

[0104] the lithium nickelate in the lithium supplement agent is lithium-rich lithium nickelate.

[0105] 22. The battery cell according to any one of aspects 1 to 21, wherein the negative electrode sheet further comprises a negative conductive layer, the negative conductive layer being disposed between the negative current collector and the negative active layer.

[0106] 23. The battery cell according to aspect 22, wherein the negative conductive layer has a thickness of 0.5-2 pm.

[0107] 24. The battery cell according to aspect 22 or 23, wherein the negative conductive layer comprises one or more of a negative conductive agent, a negative binder.

[0108] 25. The battery cell according to aspect 24, wherein the negative conductive agent comprises one or more of super conductive carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers; and / or,

[0109] the negative binder comprises one or more of styrene butadiene rubber, water-soluble unsaturated resin, water-based acrylic resin, polyvinyl alcohol, sodium alginate, carboxymethyl chitosan.

[0110] 26. The battery cell according to aspect 24 or 25, wherein the mass percentage content of the negative conductive agent is 20%-40% based on the mass of the negative conductive layer; and / or,

[0111] the mass percentage content of the negative binder is 60%-80% based on the mass of the negative conductive layer.

[0112] 27. The battery cell according to any one of aspects 1 to 26, wherein the negative active layer is a single-layer or multi-layer structure, and the volume average particle size Dv50 of the negative active material in the negative active layer is 7.5-19.5 pm.

[0113] 28. The battery cell according to any one of aspects 1 to 27, wherein the negative active layer is a single-layer structure, and the volume average particle size Dv50 of the negative active material is 8.0-17.5 pm.

[0114] 29. The battery cell according to any one of aspects 1 to 27, wherein the negative active layer comprises a first negative active layer proximate to the negative current collector and a second negative active layer disposed on the first negative active layer.

[0115] 30. The battery cell according to aspect 29, wherein the second negative active layer has a thickness ratio to the first negative active layer of 2:8 to 8:2.

[0116] 31. The battery cell according to any one of aspects 29 or 30, wherein the volume average particle size Dv50 of the negative active material in the first negative active layer is 7.5 to 19.5 pm or 12.5 to 18.5 pm.

[0117] 32. The battery cell according to any one of aspects 29 to 31, wherein the volume average particle size Dv50 of the negative active material in the second negative active layer is 7.5 to 19.5 pm or 7.5 to 15.5 pm.

[0118] 33. The battery cell according to any one of aspects 29 to 32, wherein the volume average particle size Dv50 of the negative active material in the second negative active layer is smaller than the volume average particle size Dv50 of the negative active material in the first negative active layer.

[0119] 34. The battery cell according to any one of aspects 29 to 33, wherein the graphite in the first negative active layer and the second negative active layer is each independently selected from one or more of natural graphite, composite graphite.

[0120] 35. The battery cell according to aspect 34, wherein the composite graphite comprises a bulk and a coating layer coated on a surface of the bulk; the bulk comprises artificial graphite, and the coating layer comprises amorphous carbon.

[0121] 36. The battery cell according to any one of aspects 34 or 35, wherein the composite graphite comprises secondary particles.

[0122] 37. The battery cell according to any one of aspects 34 to 36, wherein the composite graphite has a powder resistivity of 0.01 to 0.04 W-cm at 8 MPa.

[0123] 38. The battery cell according to any one of aspects 34 to 37, wherein the composite graphite has a powder compaction density of 1.5 to 1.85 g / cm3 or 1.55 to 1.75 g / cm3 at a pressure of 20,000 N. 3 3 .

[0124] 39. The battery cell according to any one of aspects 1 to 38, wherein the negative active material has a charge specific capacity of 350 to 550 mAh / g at a 0.1 C rate.

[0125] ​40. The battery cell according to any one of aspects 1 to 39, wherein the negative active material further comprises a silicon material.

[0126] 41. The battery cell according to aspect 40, wherein the silicon material comprises one or more of a silicon oxide compound, a silicon carbon compound; and / or,

[0127] The mass percentage of silicon element is 0.3% to 10% or 1% to 6% based on the mass of the negative electrode material.

[0128] 42. The battery cell according to any one of aspects 1 to 41, wherein the battery cell further comprises an electrolyte, and the electrolyte has an electrical conductivity of 10 to 20 mS / cm or 12 to 17 mS / cm at room temperature.

[0129] 43. The battery cell according to any one of aspects 1 to 42, wherein the battery cell further comprises a separator, and the separator comprises a porous base film and a functional film layer provided on at least one side of the porous base film.

[0130] 44. The battery cell according to aspect 43, wherein the porous base film has a thickness of ≤ 15 pm or 5 to 7 pm; and / or,

[0131] The porosity of the porous base film is 20% to 70% or 30% to 50%.

[0132] 45. The battery cell according to aspect 43 or 44, wherein the functional film layer comprises a first functional film layer and a second functional film layer provided on both sides of the porous base film, respectively, the first functional film layer comprises inorganic material particles, and the second functional film layer comprises composite particles, the composite particles comprise non-fluoropolymer particles and inorganic material particles attached to the surface of the non-fluoropolymer particles or located in the non-fluoropolymer particles.

[0133] 46. The battery cell according to any one of aspects 1 to 45, wherein the positive current collector has a thickness of 9 to 17 pm; and / or,

[0134] The negative current collector has a thickness of 4.5 to 8 pm.

[0135] 47. The battery cell according to any one of aspects 1 to 46, wherein the battery has a battery liquid injection coefficient of 2.4 to 3.1 g / Ah.

[0136] 48. The battery cell according to any one of aspects 1 to 47, wherein the battery cell has a volumetric energy density of 400 to 550 Wh / L or 430 to 500 Wh / L.

[0137] 49. A battery device comprising the battery cell according to any one of aspects 1 to 48; the battery device comprises a battery module, a battery pack or an energy storage device.

[0138] 50. An electric device comprising the battery cell of any one of aspects 1 to 48 or the battery device of aspect 49. BRIEF DESCRIPTION OF DRAWINGS

[0139] Fig. 1 is a schematic view of a battery assembly according to an embodiment of the present application.

[0140] Fig. 2 is an exploded view of a battery cell according to an embodiment of the present application.

[0141] Fig. 3 is a schematic view of a battery pack according to an embodiment of the present application.

[0142] Fig. 4 is an exploded view of the battery pack according to an embodiment of the present application shown in Fig. 3.

[0143] Fig. 5 is a schematic view of an electric device using the battery pack according to an embodiment of the present application as a power source.

[0144] BRIEF DESCRIPTION OF DRAWINGS 1: battery pack; 2: upper case; 3: lower case; 4: battery module; 5: battery cell; 51: case; 52: electrode assembly; 53: top cover assembly. DETAILED DESCRIPTION

[0145] Hereinafter, embodiments of the battery cell, the battery module, the battery pack, and the electric device according to the present application are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed description is omitted. For example, there will be cases where detailed description of matters that are already well known, repeated description of actually identical structures are omitted. This is to avoid the following description becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the drawings and the following description are provided so that those skilled in the art can fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0146] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0147] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0148] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0149] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0150] [Battery cell]

[0151] A battery cell, also known as a rechargeable battery or storage battery, is a battery that can be recharged after being discharged to activate the active materials and continue to be used.

[0152] Generally, a battery cell includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. During the charging and discharging of the battery, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive electrode sheet and the negative electrode sheet. The separator is disposed between the positive electrode sheet and the negative electrode sheet and mainly functions to prevent short circuiting of the positive and negative electrodes while allowing the active ions to pass through. The electrolyte is between the positive electrode sheet and the negative electrode sheet and mainly functions to conduct the active ions.

[0153] One embodiment of the present application provides a battery cell, comprising an electrode assembly, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet;

[0154] The negative electrode sheet comprises a negative current collector and a negative active layer on at least one side of the negative current collector, the negative active layer comprising a negative material, the negative material comprising a negative active material, the negative active material comprising graphite;

[0155] The positive electrode sheet comprises a positive current collector and a positive active layer on at least one side of the positive current collector, the positive active layer comprising a positive material, the positive material comprising a positive active material, the positive active material comprising a lithium iron phosphate material and a lithium manganese iron phosphate material;

[0156] The battery cell has a surface density of the positive active layer of 200-370 mg / 1540.25 mm 2 (e.g., 220 mg / 1540.25 mm 2 , 240 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 , 320 mg / 1540.25 mm 2 , 340 mg / 1540.25 mm 2 or a range consisting of any of the above values), and a compaction density of the positive active layer of 2.27-2.67 g / cm 3 (e.g., 2.27 g / cm 3 , 2.3 g / cm 3 , 2.32 g / cm 3 , 2.35 g / cm 3 , 2.36 g / cm 3 , 2.38 g / cm 3 , 2.4 g / cm 3 , 2.41 g / cm 3 , 2.43 g / cm 32.45 g / cm3 3 2.48 g / cm3 3 2.51 g / cm3 3 2.53 g / cm3 3 2.6 g / cm3 3 2.67 g / cm3 3 or a range of values formed by any of the above.

[0157] The inventors of the present application found that when the positive active material lithium manganese iron phosphate and lithium iron phosphate are mixed, increasing the mixing ratio of lithium manganese iron phosphate (i.e. increasing the content of manganese element in the positive active layer) is beneficial to improve the voltage platform of the positive active material and is beneficial to improve the energy density of the battery monomer; however, compared with lithium iron phosphate, the upper limit of the compaction density of lithium manganese iron phosphate in the positive electrode sheet is lower, which greatly increases the risk of powder falling and cracking of the positive active layer when the proportion of lithium manganese iron phosphate is continuously increased to continue to improve the energy density, and has a great impact on the cycle life of the battery monomer.

[0158] The present application aims to develop a battery monomer with low cost, high energy density and high cycle life by reasonably designing the positive electrode sheet of the positive active material including lithium manganese iron phosphate material and lithium iron phosphate material, and by limiting the area density and compaction density of the positive active layer under 100% SOC state.

[0159] Specifically, by limiting the area density of the positive active layer to 200-370 mg / 1540.25 mm 2 , the total amount of positive active material in the positive active layer can be controlled, and the adverse effects of too low positive active layer area density on the energy density of the battery monomer and the adverse effects of too high positive active layer area density on the cycle performance of the battery monomer due to too long lithium ion transmission distance can be reduced. However, when the positive active layer is in the above area density range, the corresponding compaction density range of the positive active layer under 100% SOC state is large: on the one hand, too large compaction density of the positive active layer under 100% SOC state will lead to an increase in material defects in the positive active layer, affecting the cycle performance of the battery monomer, and excessive compaction is also not conducive to the rapid extraction of lithium ions in the positive film layer, which is not conducive to the long-term cycle performance of the battery monomer; on the other hand, too small compaction density of the positive active layer under 100% SOC state will lead to too low energy density of the battery monomer. Therefore, in the positive active layer of the positive active material including lithium manganese iron phosphate and lithium iron phosphate, by limiting the above positive active layer area density and further limiting the compaction density of the positive active layer under 100% SOC state, it is beneficial to improve the energy density of the battery monomer while ensuring the cycle performance of the battery monomer.

[0160] And, since the 100% SOC state is the highest state in which the battery cell can release energy, at which lithium ions are extracted from the positive electrode active layer, the positive electrode active layer has good uniformity in terms of the compaction density and the surface density between different battery cells, the present application limits the numerical range of the surface density and the compaction density of the positive electrode active layer corresponding to the battery cell in the 100% SOC state.

[0161] In the present application, the 100% SOC state refers to the highest state in which the battery cell can release energy. The process of charging the battery cell to 100% SOC is not unique, for example, it can be charged to the charge cut-off voltage at 25°C with a constant current of 0.33C, and then charged to the state reached when the current is less than 0.05C at the charge cut-off voltage.

[0162] In some embodiments, the surface density of the positive electrode active layer of the battery cell in the 100% SOC state is 240-340 mg / 1540.25 mm 2 . Thus, the cycle performance and energy density of the battery cell are simultaneously improved.

[0163] In some embodiments, the compaction density of the positive electrode active layer of the battery cell in the 100% SOC state is 2.40-2.67 g / cm 3 , for example 2.45 g / cm 3 , 2.48 g / cm 3 , 2.5 g / cm 3 , 2.52 g / cm 3 , 2.54 g / cm 3 , 2.56 g / cm 3 , 2.58 g / cm 3 , 2.6 g / cm 3 , 2.62 g / cm 3 , 2.65 g / cm 3 , 2.66 g / cm 3 , 2.67 g / cm 3 , or a range consisting of any of the above values. Thus, the cycle performance and energy density of the battery cell are simultaneously improved.

[0164] In some embodiments, the compaction density of the negative electrode active layer of the battery cell in the 100% SOC state is 1.04-1.48 g / cm 3 , optionally 1.23-1.42 g / cm 3 , for example 1.1 g / cm 3 , 1.2 g / cm 3 , 1.3 g / cm 3 , 1.4 g / cm 3 .or a range consisting of any of the aforementioned values. Thus, the compaction density of the negative active layer at the 100% SOC state of the battery cell is limited in the above range, which is conducive to improving the energy density of the battery cell while ensuring the cycle performance of the battery cell.

[0165] In some embodiments, the areal density of the negative active layer of the battery cell at the 100% SOC state is 79-170 mg / 1540.25 mm 2 , optionally 90-170 mg / 1540.25 mm 2 , more optionally 100-155 mg / 1540.25 mm 2 , for example 79 mg / 1540.25 mm 2 , 80 mg / 1540.25 mm 2 , 82 mg / 1540.25 mm 2 , 84 mg / 1540.25 mm 2 , 85 mg / 1540.25 mm 2 , 87 mg / 1540.25 mm 2 , 88 mg / 1540.25 mm 2 , 90 mg / 1540.25 mm 2 , 92 mg / 1540.25 mm 2 , 95 mg / 1540.25 mm 2 , 94 mg / 1540.25 mm 2 , 96 mg / 1540.25 mm 2 , 98 mg / 1540.25 mm 2 , 99 mg / 1540.25 mm 2 , 100 mg / 1540.25 mm 2 , 120 mg / 1540.25 mm 2 , 140 mg / 1540.25 mm 2 , 150 mg / 1540.25 mm 2 , 160 mg / 1540.25 mm 2 , 170 mg / 1540.25 mm 2 or a range consisting of any of the aforementioned values. Thus, the energy density of the battery cell is further improved.

[0166] In this application, the areal density and compaction density of the positive active layer (negative active layer) are tested by conventional methods in the art. For example, a specific test method is as follows:

[0167] The positive electrode tab (negative electrode tab) with a fixed area is cut and weighed. The weight of the positive electrode current collector (negative electrode current collector) with the same area is weighed and calculated in advance. The average thickness of the positive electrode active layer (negative electrode active layer) on the positive electrode tab (negative electrode tab) is measured.

[0168] The face density of the positive electrode active layer (negative electrode active layer) is obtained by subtracting the weight of the positive electrode current collector (negative electrode current collector) from the weight of the positive electrode tab (negative electrode tab) and then dividing by the fixed area.

[0169] The compaction density of the positive electrode active layer (negative electrode active layer) is obtained by dividing the face density of the positive electrode active layer (negative electrode active layer) by the average thickness of the positive electrode active layer (negative electrode active layer).

[0170] The face density and compaction density of the positive electrode active layer (negative electrode active layer) at 100% SOC of the battery cell are obtained by testing according to the above method at 100% SOC of the battery cell.

[0171] In some embodiments, the mass percentage of manganese element is 2.1%-25%, for example, 2.5%, 2.7%, 3%, 4%, 5%, 6%, 6.5%, 7%, 7.3%, 7.5%, 8%, 8.5%, 9%, 9.3%, 9.5%, 9.6%, 9.9%, 10%, 10.5%, 11%, 11.5%, 11.9%, 12%, 12.5%, 13%, 13.5%, 13.9%, 14%, 14.5%, 15%, 15.5%, 15.8%, 16%, 16.5%, 16.8%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 22%, 23%, 24%, 25%, or a range consisting of any of the above values, based on the mass of the positive electrode material. In this way, the mass content of manganese element in the positive electrode material is limited within the above range, which is beneficial to improving the energy density of the battery cell while ensuring the cycle performance of the battery cell.

[0172] In some embodiments, the positive electrode active material further comprises one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb.

[0173] In some embodiments, the powder compaction density of the positive electrode material at 30,000 N is 2.3-2.7 g / cm 3 , optionally 2.43-2.6 g / cm 3 , for example 2.34 g / cm 3 , 2.38 g / cm3 2.4 g / cm3 3 2.45 g / cm3 3 2.5 g / cm3 3 2.54 g / cm3 3 2.6 g / cm3 3 2.65 g / cm3 3 2.7 g / cm3 3 or a range derived from any of the above.

[0174] In some embodiments, the BET specific surface area of the positive electrode material is 7.5-16 m2 / g, for example 7.5 m2 / g, 8 m2 / g, 9 m2 / g, 10 m2 / g, 11 m2 / g, 12 m2 / g, 13 m2 / g, 14 m2 / g, 15 m2 / g, 16 m2 / g or a range derived from any of the above. 2 2 2 2 2 2 2 2 2 2 2 or a range derived from any of the above.

[0175] In some embodiments, the volume average particle size Dv50 of the positive electrode material is 0.35-2 pm, optionally 0.85-2 pm or 0.35-1.2 pm, for example 0.35 pm, 0.4 pm, 0.54 pm, 0.6 pm, 0.65 pm, 0.68 pm, 0.7 pm, 0.75 pm, 0.8 pm, 0.82 pm, 0.9 pm, 1 pm, 1.1 pm, 1.2 pm, 1.5 pm, 1.7 pm, 1.8 pm, 1.9 pm, 2 pm or a range derived from any of the above.

[0176] In the present application, the BET specific surface area of the positive electrode material is tested by a conventional method in the art. For example, a specific testing method is as follows: disassemble the positive electrode sheet of the battery monomer, clean the positive electrode sheet, and collect the positive electrode material in the positive electrode active layer after drying and calcining the positive electrode sheet. Referring to GB / T 19587-2017, the BET specific surface area of the positive electrode material is calculated by the BET (Brunauer Emmett Teller) method using the nitrogen adsorption specific surface area analysis test method, wherein the nitrogen adsorption specific surface area analysis test can be performed by a Tri-Star 3020 specific surface area pore size analyzer of the United States Micromeritics Company.

[0177] ​​​​​​​​​​The volume average particle size Dv50 refers to the particle size at which 50% of the volume of the powder particles is reached from the small particle size side in the particle size distribution based on volume. In the present application, the volume average particle size Dv50 is tested by a conventional method in the art. For example, a specific test method is as follows: the positive electrode sheet of the battery monomer is disassembled, the positive electrode sheet is washed, and the positive electrode material in the positive electrode active layer is collected after the positive electrode sheet is dried and calcined. The Dv50 particle size of the positive electrode material can be determined by a Malvern 3000 laser particle size analyzer according to the standard process and requirements of GB / T 19077.1-2016 / ISO 13320:2009 particle size distribution laser diffraction method.

[0178] In the present application, the powder compaction density of the positive electrode material is tested by a conventional method in the art. For example, a specific test method is as follows: the positive electrode sheet of the battery monomer is washed, and the positive electrode material in the positive electrode active layer is collected after the positive electrode sheet is dried and calcined. The positive electrode material powder is weighed in the compaction density tester mold, and the tester automatically applies a target pressure to the powder to compact the powder. According to the cross-sectional area of the mold and the thickness of the powder at this time, the volume of the powder can be calculated, and the compaction density = mass / volume, so the powder compaction density result can be measured.

[0179] In some embodiments, the mass ratio of the lithium iron phosphate material to the lithium manganese iron phosphate material is 1:9-9:1, which can be 3:7-7:3, for example, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, or a range consisting of any of the above values.

[0180] In some embodiments, the positive electrode active material further comprises carbon;

[0181] Optionally, the mass percentage of the carbon is 1%-3% based on the mass of the positive electrode material, for example, 1%, 1.5%, 2%, 2.5%, 3%, or a range consisting of any of the above values.

[0182] Therefore, the conductivity of the positive electrode active material is further improved.

[0183] In some embodiments, the positive electrode sheet further comprises a positive electrode conductive layer, and the positive electrode conductive layer is arranged between the positive electrode current collector and the positive electrode active layer.

[0184] In some embodiments, the thickness of the positive electrode conductive layer is 0.5-2 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, or a range consisting of any of the above values.

[0185] In some embodiments, the positive electrode conductive layer comprises one or more of a positive electrode conductive agent and a positive electrode binder.

[0186] In some embodiments, the battery cell comprises one or more of the following:

[0187] The positive electrode conductive agent comprises one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers;

[0188] The positive electrode conductive agent comprises at least super P and carbon nanotubes;

[0189] The positive electrode binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, and fluorine-containing acrylic ester resin.

[0190] In some embodiments, the mass percentage of the positive electrode conductive agent is 30%-50%, for example, 30%, 35%, 40%, 45%, 50%, or a range consisting of any of the aforementioned values, based on the mass of the positive electrode conductive layer; and / or,

[0191] The mass percentage of the positive electrode binder is 50%-70%, for example, 50%, 55%, 60%, 65%, 70%, or a range consisting of any of the aforementioned values, based on the mass of the positive electrode conductive layer.

[0192] In some embodiments, the lithium iron phosphate material has a chemical formula of Li x Fe (1-s) M s P y O z wherein x is greater than or equal to 0.5 and less than or equal to 1.3 (for example, 0.5, 0.6, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or a range consisting of any of the aforementioned values), s is greater than or equal to 0 and less than 1 (for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range consisting of any of the aforementioned values), y is greater than or equal to 0.5 and less than or equal to 1.3 (for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or a range consisting of any of the aforementioned values), z is greater than or equal to 3 and less than or equal to 5 (for example, 3, 4, 5, or a range consisting of any of the aforementioned values), and M comprises one or more of 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, Hf, Ni, Co, Ru, Ag, Pb.

[0193] In some embodiments, the lithium manganese iron phosphate material has a chemical formula of Li xFe (1-t-s) Mn t M s P y O z wherein x is greater than or equal to 0.5 and less than or equal to 1.3 (e.g., 0.5, 0.6, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or a range of any of the foregoing), t is greater than 0 and less than 1 (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range of any of the foregoing), s is greater than or equal to 0 and less than 1 (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range of any of the foregoing), 1-t-s is greater than 0 and less than 1 (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range of any of the foregoing), y is greater than or equal to 0.5 and less than or equal to 1.3 (e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or a range of any of the foregoing), z is greater than or equal to 3 and less than or equal to 5 (e.g., 3, 4, 5, or a range of any of the foregoing), and M comprises one or more elements of 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, Hf, Ni, Co, Ru, Ag, Pb.

[0194] In some embodiments, the positive active layer further comprises a lithium supplement agent, the lithium supplement agent comprising one or more of lithium nickel cobalt manganese oxide, lithium ferrite, lithium nickelate, lithium cobaltate, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium manganite, lithium tartrate, trilithium citrate, lithium oxide, lithium fluoride, lithium sulfide, lithium nitride;

[0195] Optionally, the lithium ferrite in the lithium supplement agent is lithium-rich lithium ferrite.

[0196] Optionally, the lithium nickelate in the lithium supplement agent is lithium-rich lithium nickelate.

[0197] In some embodiments, the negative electrode tab further comprises a negative electrode conductive layer, the negative electrode conductive layer being disposed between the negative electrode current collector and the negative electrode active layer.

[0198] In some embodiments, the negative electrode conductive layer has a thickness of 0.5-2 μm, e.g., 0.5 μm, 1 μm, 1.5 μm, 2 μm, or a range of any of the foregoing.

[0199] In some embodiments, the negative electrode conductive layer comprises one or more of a negative electrode conductive agent, a negative electrode binder.

[0200] In some embodiments, the negative electrode conductive agent comprises one or more of super P, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers; and / or,

[0201] The negative electrode binder comprises one or more of styrene butadiene rubber, water-soluble unsaturated resin, water-based acrylic resin, polyvinyl alcohol, sodium alginate, carboxymethyl chitosan.

[0202] In some embodiments, the mass percentage of the negative electrode conductive agent is 20%-40%, for example 20%, 25%, 30%, 35%, 40% or a range consisting of any of the aforementioned values, based on the mass of the negative electrode conductive layer; and / or,

[0203] The mass percentage of the negative electrode binder is 60%-80%, for example 60%, 65%, 70%, 75%, 80% or a range consisting of any of the aforementioned values, based on the mass of the negative electrode conductive layer.

[0204] In some embodiments, the negative electrode active layer is a single-layer or multi-layer structure, and the volume average particle size Dv50 of the negative electrode active material in the negative electrode active layer is 7.5-19.5 μm, for example 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm or a range consisting of any of the aforementioned values.

[0205] In this application, a multi-layer structure refers to a structure of two or more than two layers.

[0206] In some embodiments, the negative electrode active layer is a single-layer structure, and the volume average particle size Dv50 of the negative electrode active material is 8.0-17.5 μm, for example 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm or a range consisting of any of the aforementioned values.

[0207] In some embodiments, the negative active layer comprises a first negative active layer adjacent to the negative current collector and a second negative active layer disposed on the first negative active layer.

[0208] In some embodiments, the thickness ratio of the second negative active layer to the first negative active layer is 2:8-8:2, for example 1:1.

[0209] In some embodiments, the volume average particle size Dv50 of the negative active material in the first negative active layer is 7.5-19.5 μm, optionally 12.5-18.5 μm, for example 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm, or a range consisting of any of the aforementioned values.

[0210] In some embodiments, the volume average particle size Dv50 of the negative active material in the second negative active layer is 7.5-19.5 μm, optionally 7.5-15.5 μm, for example 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm, or a range consisting of any of the aforementioned values.

[0211] In some embodiments, the volume average particle size Dv50 of the negative active material in the second negative active layer is smaller than the volume average particle size Dv50 of the negative active material in the first negative active layer. Thereby, it is beneficial to improve the discharge power of the battery cell while increasing the energy density of the battery cell and reducing the cost.

[0212] In some embodiments, the graphite in the first negative active layer and the second negative active layer is each independently selected from one or more of natural graphite, composite graphite.

[0213] In some embodiments, the composite graphite comprises a body and a coating layer coated on the surface of the body; the body comprises artificial graphite, and the coating layer comprises amorphous carbon.

[0214] In some embodiments, the composite graphite comprises secondary particles.

[0215] In some embodiments, the composite graphite has a powder resistivity of 0.01-0.04 Ω·cm at 8 MPa.

[0216] In some embodiments, the composite graphite has a powder compaction density of 1.5-1.85 g / cm 3 , optionally 1.55-1.75 g / cm 3 .

[0217] In some embodiments, the negative electrode material has a charge gram capacity of 350-550 mAh / g at a 0.1C rate.

[0218] In some embodiments, the negative electrode active material further comprises a silicon material.

[0219] In some embodiments, the silicon material comprises one or more of a silicon oxide compound and a silicon carbon compound; and / or,

[0220] The mass percentage of the silicon element is 0.3%-10%, optionally 1%-6%, for example 1%, 2%, 3%, 5%, 6%, or a range consisting of any of the aforementioned values, based on the mass of the negative electrode material.

[0221] In this application, the mass ratio of manganese element and carbon element in the positive electrode material and the mass ratio of silicon element in the negative electrode material are tested by conventional methods in the art. For example, a specific test method is as follows: the positive electrode sheet (negative electrode sheet) of the battery monomer is disassembled, the positive electrode sheet (negative electrode sheet) is cleaned, and the positive electrode active layer (negative electrode active layer) is collected after the positive electrode sheet (negative electrode sheet) is dried and calcined. The mass ratio of manganese element and carbon element in the positive electrode material or the mass ratio of silicon element in the negative electrode material is obtained by testing multiple points in the positive electrode material or the negative electrode material by SEM-EDS combined instrument, taking the average value.

[0222] In this application, the charge gram capacity of the negative electrode material at a 0.1C rate is tested by conventional methods in the art. For example, a specific test method is as follows: the double-sided coated negative electrode sheet in the battery monomer is disassembled, the negative electrode material is scraped off from one side of the negative electrode current collector and weighed, multiple negative electrode sheets of the same area are subjected to the above operation, and the average weight of the negative electrode material on one side of the negative electrode sheet is obtained. The same area of the single-sided negative electrode sheet is used to prepare a button cell, which is charged to the upper limit cutoff voltage at 0.1C rate at 25°C, and then charged to 0.05C, and then discharged to the lower limit cutoff voltage at 0.1C rate after standing for 30 min. The charge capacity is repeated twice, and the last charge capacity Cn is recorded. The test result is obtained by dividing the last charge capacity Cn by the weight m of the negative electrode material on one side.

[0223] In some embodiments, the battery cell further comprises an electrolyte, and the electrolyte has an electrical conductivity of 10-20 mS / cm, optionally 12-17 mS / cm, at room temperature.

[0224] In some embodiments, the battery cell further comprises a separator film, and the separator film comprises a porous base film and a functional film layer arranged on at least one side of the porous base film.

[0225] In some embodiments, the porous base film has a thickness of 5-7 pm; and / or,

[0226] The porous base film has a porosity of 20%-70%, optionally 30%-50%.

[0227] In some embodiments, the functional film layer comprises a first functional film layer and a second functional film layer arranged on two sides of the porous base film respectively, the first functional film layer comprises inorganic material particles, and the second functional film layer comprises composite particles, and the composite particles comprise non-fluoropolymer particles and inorganic material particles attached to the surface of the non-fluoropolymer particles or located in the non-fluoropolymer particles.

[0228] In some embodiments, the positive current collector has a thickness of 9-17 pm; and / or,

[0229] The negative current collector has a thickness of 4.5-8 pm.

[0230] In some embodiments, the battery cell has a liquid injection coefficient of 2.4-3.1 g / Ah.

[0231] In some embodiments, the battery cell has a volumetric energy density of 400-550 Wh / L, optionally 430-500 Wh / L.

[0232] In the present application, the positive electrode material refers to the material of the positive electrode active layer collected from the surface of the positive current collector after the positive electrode sheet is cleaned, dried and calcined. The positive electrode material includes the positive electrode active material and / or its calcined product, and also includes the auxiliary agent used for preparing the positive electrode sheet and / or its calcined product. The auxiliary agent includes, but is not limited to, the positive electrode binder, the positive electrode conductive agent, the positive electrode film-forming agent, etc.

[0233] In the present application, the negative electrode material refers to the material of the negative electrode active layer collected from the surface of the negative current collector after the negative electrode sheet is cleaned, dried and calcined. The negative electrode material includes the negative electrode active material and / or its calcined product, and also includes the auxiliary agent used for preparing the negative electrode sheet and / or its calcined product. The auxiliary agent includes, but is not limited to, the negative electrode binder, the negative electrode thickening agent, the negative electrode conductive agent, the negative electrode film-forming agent, etc.

[0234] In the present application, the mass percentage of manganese in the positive electrode material, the types of elements in the active material of the positive electrode material, the powder compaction density of the positive electrode material, the BET specific surface area of the positive electrode material, and the volume average particle size Dv50 of the positive electrode material can be tested when the battery monomer is in any state between 0% SOC and 100% SOC. The above state changes of the battery monomer do not substantially affect the test results.

[0235] [Positive electrode sheet]

[0236] The battery monomer will be accompanied by Li deintercalation and consumption during the charging and discharging process, and the molar content of Li is different when the battery monomer is discharged to different states. In the present application, the molar content of Li in the listing of positive active materials is the initial state of the material, i.e., the state before feeding, and the positive active material is applied to the battery system. After charging and discharging cycles, the molar content of Li will change.

[0237] In the present application, the molar content of O in the listing of positive active materials is only the theoretical state value, and the release of oxygen from the crystal lattice will cause the molar content of oxygen to change, and the actual molar content of O will fluctuate.

[0238] As an example, the positive current collector has two opposite surfaces in the thickness direction of itself, and the positive film layer is arranged on any one or both of the two opposite surfaces of the positive current collector.

[0239] In some embodiments, the positive current collector can adopt a metal foil or a composite current collector. For example, as a metal foil, an aluminum foil can be adopted. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0240] In some embodiments, the positive active material can also employ positive active materials for battery cells known in the art. As an example, the positive active material can also include at least one of lithium transition metal oxides and modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as positive active materials for batteries can also be used. These positive active materials can be used alone only or in combination of two or more. Among them, examples of the lithium transition metal oxides can include, but are not limited to, lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium iron oxide (e.g., Li5FeO4), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 O2), modified compounds thereof, and the like.

[0241] In some embodiments, the positive active layer can also optionally include a binder. As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0242] In some embodiments, the positive active layer can also optionally include a conductive agent. As an example, the conductive agent can include at least one of super P, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0243] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder, and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector; and drying, cold-pressing, or the like.

[0244] [Anode sheet]

[0245] As an example, the anode current collector has two surfaces opposite in the thickness direction thereof, and the anode film layer is provided on either one or both of the two surfaces of the anode current collector.

[0246] In some embodiments, the anode current collector can employ a metal foil or a composite current collector. As a metal foil, for example, a copper foil can be employed. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material base layer (e.g., a base layer of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0247] In some embodiments, the anode active material can also employ an anode active material for a battery cell known in the art. As an example, the anode active material can also include at least one of the following materials: soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material can be selected from at least one of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as an anode active material for a battery cell can also be used. These anode active materials can be used alone or in combination of two or more.

[0248] In some embodiments, the anode active layer can also optionally include a binder. As an example, the binder can be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0249] In some embodiments, the anode active layer can also optionally include a conductive agent. As an example, the conductive agent can be selected from at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dot, carbon nanotube, graphene, and carbon nanofiber.

[0250] In some embodiments, the negative active layer can also optionally include other auxiliary agents, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na)), etc.

[0251] In some embodiments, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as the negative active material, the conductive agent, the binder, and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, and after processes such as drying, cold pressing, etc., the negative electrode sheet can be obtained.

[0252] [Electrolyte]

[0253] The electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet. The type of the electrolyte is not particularly limited in the present application, and can be selected as needed.

[0254] In some embodiments, the electrolyte includes an electrolyte salt and a solvent.

[0255] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorobisoxalate borate, lithium bisoxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorodioxalate phosphate.

[0256] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0257] In some embodiments, the electrolyte can also optionally include an additive. As an example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can also include an additive capable of improving certain properties of the battery cell, such as an additive for improving overcharge performance of the battery cell, an additive for improving high-temperature or low-temperature performance of the battery cell, etc.

[0258] [Separator]

[0259] In some embodiments, the battery cell further includes a separator. The type of the separator is not particularly limited in the present application, and any known porous structure separator having good chemical stability and mechanical stability can be used.

[0260] In some embodiments, the material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited.

[0261] In some embodiments, the positive electrode tab, the negative electrode tab, and the separator film can be used to form an electrode assembly through a winding process or a stacking process.

[0262] In some embodiments, the battery cell can include an outer package. The outer package can be used to encapsulate the electrode assembly and the electrolyte described above.

[0263] In some embodiments, the outer package of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The outer package of the battery cell can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, and as plastic, polypropylene, polybutylene terephthalate, polybutylene succinate, or the like can be listed.

[0264] The shape of the battery cell is not particularly limited in the present application, and can be cylindrical, square, or any other shape. For example, FIG. 1 is an electrode assembly 52 of a battery cell in a square structure as an example.

[0265] In some embodiments, referring to FIG. 2, the outer package can include a shell 51 and a cover plate 53. The shell 51 can include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be arranged on the opening to close the receiving cavity. The positive electrode tab, the negative electrode tab, and the separator film can be used to form an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and a person skilled in the art can select according to the specific actual needs.

[0266] In some embodiments, the battery cell can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by a person skilled in the art according to the application and capacity of the battery module.

[0267] In the battery module, the plurality of battery cells can be arranged in sequence along the length direction of the battery module. Of course, they can also be arranged in any other manner. Further, the plurality of battery cells can be fixed by fasteners.

[0268] Optionally, the battery module can further include a housing having a receiving space, and the plurality of battery cells are received in the receiving space.

[0269] In some embodiments, the battery module described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0270] Figs. 3 and 4 are a battery pack 1 as an example. Referring to Figs. 3 and 4, the battery pack 1 can include a battery case and a plurality of battery modules 4 disposed in the battery case. The battery case includes an upper case 2 and a lower case 3, and the upper case 2 can be disposed on the lower case 3 to form an enclosed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery case in any manner.

[0271] In addition, the present application also provides a power utilization device, which includes at least one of the battery cell, the battery module, or the battery pack provided by the present application. The battery cell, the battery module, or the battery pack can be used as a power supply of the power utilization device, or can be used as an energy storage unit of the power utilization device. The power utilization device can include a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto.

[0272] As the power utilization device, the battery cell, the battery module, or the battery pack can be selected according to the use requirements thereof.

[0273] Fig. 5 is a power utilization device as an example. The power utilization device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the high power and high energy density requirements of the battery cell for the power utilization device, the battery pack or the battery module can be used.

[0274] [Embodiments]

[0275] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are intended to explain the present application, and should not be understood as limiting the present application. In the embodiments, specific techniques or conditions not mentioned are performed according to the techniques or conditions described in the literature in the art or according to the product manual. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be obtained on the market.

[0276] Example 1

[0277] (1) Positive electrode sheet: The two sides of the positive electrode current collector aluminum foil (thickness 13 μm) are provided with positive electrode conductive layers, and the positive electrode active layers are provided on the two sides of the positive electrode conductive layers. The positive electrode conductive layer is a film layer formed by uniformly mixing the positive electrode conductive agent superconducting carbon, the positive electrode binder polyacrylate and the solvent, coating on the surface of the positive electrode current collector and drying, the thickness is 1 μm, the mass content of the positive electrode conductive agent in the positive electrode conductive layer is 50%, and the mass content of the positive electrode binder in the positive electrode conductive layer is 50%. The positive electrode active layer includes positive electrode active materials lithium manganese iron phosphate and lithium iron phosphate (mass ratio 7:3), binder polyvinylidene fluoride (PVDF), and conductive agent acetylene black, and the mass ratio of the three is 97:2:1.

[0278] (2) Negative electrode sheet: The two sides of the negative electrode current collector copper foil (thickness 6 μm) are provided with negative electrode conductive layers, and the negative electrode active layers are provided on the two sides of the negative electrode conductive layers. The negative electrode conductive layer is a film layer formed by uniformly mixing the negative electrode conductive agent superconducting carbon, the negative electrode binder styrene butadiene rubber SBR, the thickening agent sodium carboxymethyl cellulose (CMC-Na) and the solvent water, coating on the surface of the negative electrode current collector and drying, the thickness is 1 μm, the mass content of the negative electrode conductive agent in the negative electrode conductive layer is 35%, the mass content of the negative electrode binder in the negative electrode conductive layer is 60%, and the mass content of the thickening agent in the negative electrode conductive layer is 5%. The negative electrode active layer includes two layers of upper layer (far from the current collector) and lower layer (close to the current collector), the thickness ratio of the two layers of negative electrode active layer is 1:1, and the two layers of negative electrode active layer each include negative electrode active material, conductive agent acetylene black, binder styrene butadiene rubber (SBR), and thickening agent sodium carboxymethyl cellulose (CMC-Na) with a mass ratio of 96:1:2:1. The Dv50 particle size of the negative electrode active material in the upper layer is 12.3 μm, and the Dv50 particle size of the negative electrode active material in the lower layer is 15.31 μm. The negative electrode active material in the upper and lower layers is a mixture of composite graphite and silicon with a mass ratio of 97:3 (the composite graphite particles include artificial graphite and a carbon coating layer, the carbon coating layer is coated on the surface of the artificial graphite, and the mass content of the carbon coating layer is 3.5%), wherein the Dv50 of the composite graphite particles is 15.4 μm, and the powder compaction density under a pressure of 20,000 N is 1.74 g / cm 3 .

[0279] The compaction density of the entire negative electrode active layer under the 100% SOC state of the battery 100 is 1.41 g / cm 3 .

[0280] (3) Separation film: A polyethylene (PE) film coated with a nano-aluminum oxide coating is used as the separation film, and the thickness is 5 μm.

[0281] (4) Electrolyte: including organic solvent ethyl acetate EA, ethylene carbonate EC, methyl ethyl carbonate EMC (mass ratio 50:35:15), the electrolyte includes 10.5 mass% of lithium hexafluorophosphate (LiPF6) and 4.5 mass% of lithium bisfluorosulfonylimide LiFSI as lithium salt, and also includes 2.5 mass% of additive vinylene carbonate VC, 1 mass% of fluoroethylene carbonate FEC, 0.5 mass% of 1,3 propylene sulfite PS, 0.5 mass% of vinyl sulfite DTD, and 0.5 mass% of lithium difluorophosphate LiPO2F2. The conductivity of the electrolyte is 13 mS / cm.

[0282] (5) Battery cell: including the positive electrode sheet, the separator film and the negative electrode sheet arranged in a stack to obtain an electrode assembly. The electrode assembly is added into an outer packaging square aluminum shell (length 600 mm, thickness 19 mm, height 105 mm), and after drying, the electrolyte is injected, and the injection coefficient is 2.9 g / Ah. After the processes of packaging, high-temperature standing, formation, secondary injection, aging, capacity, etc., the battery cell is obtained.

[0283] The battery cell preparation method of Example 2-19 and Comparative Example 1-4 is similar to that of Example 1, and the different parameters are as follows and Table 1.

[0284] Example 8

[0285] The compaction density of the entire negative electrode active layer under the 100% SOC state of the battery cell is 1.34 g / cm 3 .

[0286] The remaining parameters are shown in Table 1, and the parameters not embodied are the same as those of Example 1.

[0287] Example 13

[0288] In the negative electrode sheet, the negative electrode active material in the upper layer and the lower layer is a mixture of composite graphite and silicon with a mass ratio of 94:6 (the composite graphite particles include artificial graphite and a carbon coating layer, the carbon coating layer is coated on the surface of the artificial graphite, and the mass content of the carbon coating layer is 3.5%), and the Dv50 of the composite graphite particles is 15.4 μm, and the powder compaction density under a pressure of 20,000 N is 1.74 g / cm 3 . The Dv50 particle size of the negative electrode active material in the upper layer is 12.2 μm, and the Dv50 particle size of the negative electrode active material in the lower layer is 15.12 μm.

[0289] The compaction density of the entire negative electrode active layer under the 100% SOC state of the battery cell is 1.37 g / cm 3 .

[0290] The remaining parameters are shown in Table 1, and the parameters not embodied are the same as those of Example 1.

[0291] Example 18

[0292] In the negative electrode tab, the negative electrode active material in the upper layer and the lower layer is composite graphite, the Dv50 particle size of the composite graphite in the lower layer is 15.43 pm, and the Dv50 particle size of the composite graphite in the upper layer is 12.4 pm.

[0293] The compaction density of the entire negative electrode active layer under the 100% SOC state of the battery monomer is 1.44 g / cm 3 .

[0294] The remaining parameters are shown in Table 1, and the parameters not embodied are the same as those of Example 1.

[0295] Example 19

[0296] The negative electrode active layer in the negative electrode tab is a single layer, and the negative electrode active material in the negative electrode active layer is composite graphite (composite graphite particles include artificial graphite and a carbon coating layer, the carbon coating layer is coated on the surface of the artificial graphite, and the mass content of the carbon coating layer is 3.5%), wherein the Dv50 of the composite graphite particles is 15.4 pm, and the powder compaction density under a pressure of 20,000 N is 1.74 g / cm 3 .

[0297] The compaction density of the entire negative electrode active layer under the 100% SOC state of the battery monomer is 1.44 g / cm 3 .

[0298] The remaining parameters are shown in Table 1, and the parameters not embodied are the same as those of Example 1.

[0299] Parameter test

[0300] Test of mass ratio of manganese element and carbon element in the positive electrode material and mass ratio of silicon element in the negative electrode material: disassemble the positive electrode tab (negative electrode tab) of the battery monomer, wash the positive electrode tab (negative electrode tab) with DMC (dimethyl carbonate), and collect the positive electrode material (negative electrode material) in the positive electrode active layer (negative electrode active layer) after drying and calcining the positive electrode tab (negative electrode tab). Test multiple points (such as 50) in the positive electrode material or negative electrode material by SEM-EDS combined instrument, take the average value, and obtain the mass ratio of manganese element and carbon element in the positive electrode material or the mass ratio of silicon element in the negative electrode material.

[0301] Test method of the area density and the compaction density of the positive electrode active layer (negative electrode active layer):

[0302] Cut the positive electrode tab (negative electrode tab) of a fixed area and weigh it, weigh and calculate the weight of the positive electrode current collector (negative electrode current collector) of the same area in advance, and measure the average thickness of the positive electrode active layer (negative electrode active layer) on the positive electrode tab (negative electrode tab).

[0303] The areal density of the positive active layer (negative active layer) is obtained by subtracting the weight of the positive current collector (negative current collector) from the weight of the positive electrode sheet (negative electrode sheet), and then dividing by the fixed area.

[0304] The compaction density of the positive active layer (negative active layer) is obtained by dividing the areal density of the positive active layer (negative active layer) by the average thickness of the positive active layer (negative active layer).

[0305] The compaction density of the positive active layer (negative active layer) at 100% SOC of the battery cell is obtained by the above method. The process of charging the battery cell to 100% SOC may be, for example, charging the battery cell at 25°C to 4.1V at 0.33C constant current, and then charging at 4.1V constant voltage to the state reached when the current is less than 0.05C.

[0306] Method for testing the BET specific surface area of the positive material: The positive electrode sheet of the battery cell is disassembled, the positive electrode sheet is washed thoroughly with DMC (dimethyl carbonate), and the positive material in the positive active layer is collected after the positive electrode sheet is dried and calcined. Referring to GB / T 19587-2017, the nitrogen adsorption specific surface area analysis test method is used for testing, and the BET (Brunauer Emmett Teller) method is used for calculation to obtain the BET specific surface area of the positive material. The nitrogen adsorption specific surface area analysis test can be performed by a Tri-Star 3020 specific surface area and pore size analyzer of the Micromeritics company in the United States.

[0307] The volume average particle size Dv50 refers to the particle size at which 50% of the volume is accumulated from the small particle size side in the particle size distribution based on volume. The positive electrode sheet of the battery cell is disassembled, the positive electrode sheet is washed thoroughly with DMC (dimethyl carbonate), and the positive material in the positive active layer is collected after the positive electrode sheet is dried and calcined. The Dv50 particle size of the positive material can be determined by a Malvern 3000 laser particle size analyzer according to the standard process and requirements of GB / T 19077.1-2016 / ISO 13320:2009 particle size distribution laser diffraction method.

[0308] Charging specific capacity test method of negative electrode material at 0.1C rate: disassemble the double-coated negative electrode sheet from the battery monomer, scrape off the negative electrode material from one side of the negative electrode current collector and weigh it, take 6 negative electrode sheets of the same area to perform the above operation, and take the average weight to obtain the weight m of the negative electrode material on one side of the negative electrode sheet. Use the same area of the single-sided negative electrode sheet to prepare a button cell, charge to the upper limit cutoff voltage at 0.1C rate at 25°C, then charge to 0.05C, stand for 30 min, then discharge to the lower limit cutoff voltage at 0.1C rate, repeat the charge and discharge twice, and record the last charge capacity as Cn. Divide the last charge capacity Cn by the weight m of the negative electrode material on one side to obtain the test result.

[0309] Powder compaction density test method of positive electrode material: the positive electrode sheet of the battery monomer is washed with DMC (dimethyl carbonate), and the positive electrode material in the positive electrode active layer is collected after the positive electrode sheet is dried and calcined. Weigh the positive electrode material powder in the compaction density tester mold, and the tester automatically applies a target pressure to the powder to compact it. According to the cross-sectional area of the mold and the thickness of the powder at this time, the volume of the powder can be calculated. According to the compaction density = mass / volume, the powder compaction density result can be measured.

[0310] Battery test

[0311] (1) Volume energy density test of battery monomer:

[0312] Place the battery monomer at 25°C, charge to 4.1V at 0.33C constant current, then charge to 0.05C at constant voltage; discharge to 2.5V at 0.33C constant current, record the discharge capacity A0 and discharge platform voltage V at this time; measure the length, thickness and height of the battery monomer using a caliper (generally calculated based on the size of the battery monomer shell, excluding the height of the electrode terminal and excluding the insulating film outside the shell), calculate the volume V0 of the battery monomer; the volume energy density VED of the battery monomer is (A0xV) / V0, unit Wh / L.

[0313] (2) Cycle performance test of battery monomer:

[0314] At 30°C, charge the battery monomer to the charge cutoff voltage 4.1V (the charge cutoff voltage of the battery monomer with pure lithium iron phosphate as the positive electrode active material is 3.8V) at 1C constant current, then discharge to 2.0V at 1C constant current, which is one charge and discharge cycle, record the first cycle discharge capacity C0, repeat the above charge and discharge cycle 1000 times, record the last cycle discharge capacity Cn, and calculate the cycle capacity retention rate (i.e. Cn / C0x100%).

[0315] In the following table, the chemical formula of the lithium iron manganese phosphate material also contains M1 elements in addition to Li, Fe and Mn, the mass content of the M1 elements in the lithium iron manganese phosphate material is trace amount, thus not expressed in the chemical formula thereof, but still considered that the M1 elements are contained in the lithium iron manganese phosphate material shown in the table, the sum of the subscripts of Fe and Mn in the chemical formula of the lithium iron manganese phosphate material and the total moles of the M1 elements in the chemical formula is 1. The chemical formula of the lithium iron phosphate material also contains M2 elements in addition to Li and Fe, the mass content of the M2 elements in the lithium iron phosphate material is trace amount, thus not expressed in the chemical formula thereof, but still considered that the M2 elements are contained in the lithium iron phosphate material shown in the table, the sum of the subscript of Fe in the chemical formula of the lithium iron phosphate material and the total moles of the M2 elements in the chemical formula is 1. The M1 elements and the M2 elements can be the same or different.

[0316] Table 2

[0317] It can be seen from the above table that, compared with the too high tap density of the positive electrode active layer of the comparative example 1 at the 100% SOC state of the battery, the cycle performance of the battery monomer of the present application examples 1-19 is obviously improved.

[0318] Table 3

[0319] It can be seen from the above table that, compared with the too low areal density of the positive electrode active layer of the comparative example 2 at the 100% SOC state of the battery, the energy density of the battery monomer of the present application examples 1-19 is obviously higher.

[0320] Table 4

[0321] It can be seen from the above table that, compared with the too high areal density of the positive electrode active layer of the comparative example 3, the cycle performance of the battery monomer of the present application examples 1-19 is obviously improved.

[0322] Table 5

[0323] It can be seen from the above table that, compared with the too low areal density of the positive electrode active layer of the comparative example 4, the energy density of the battery monomer of the present application examples 1-19 is obviously higher.

[0324] Table 6

[0325] It can be seen from the above table that, the tap density of the positive electrode active layer at the 100% SOC state of the battery is reduced, which is beneficial to improve the cycle performance of the battery monomer.

[0326] Table 7

[0327] From the above table, the compaction density of the positive active layer under the 100% SOC state of the battery is increased, which is beneficial to improve the energy density of the battery monomer.

[0328] Table 8

[0329] From the above table, the areal density of the positive active layer is increased, which is beneficial to improve the energy density of the battery monomer.

[0330] Table 9

[0331] From the above table, the areal density of the positive active layer is reduced, which is beneficial to improve the cycle performance of the battery monomer.

[0332] Table 10

[0333] From the above table, the compaction density of the negative active layer under the 100% SOC state of the battery is reduced, which is beneficial to improve the cycle performance of the battery monomer.

[0334] Table 11

[0335] From the above table, the mass content of manganese elements in the positive electrode material is increased, which is beneficial to improve the energy density of the battery monomer.

[0336] Table 12

[0337] From the above table, the mass content of manganese elements in the positive electrode material is reduced, which is beneficial to improve the cycle performance of the battery monomer.

[0338] Table 13

[0339] From the above table, the mass proportion of silicon elements in the negative active material is increased, which is beneficial to improve the energy density of the battery monomer. Gr is composite graphite.

[0340] Table 14

[0341] From the above table, the mass proportion of manganese iron lithium phosphate material in the positive active material is increased, which is beneficial to improve the energy density of the battery monomer.

[0342] Table 15

[0343] From the above table, the mass proportion of manganese iron lithium phosphate material in the positive active material is reduced, which is beneficial to improve the cycle performance of the battery monomer.

[0344] Table 16

[0345] As can be seen from the above table, the mass proportion of silicon element in the negative active material is reduced, which is beneficial to improve the cycle performance of the battery monomer. Gr is composite graphite.

[0346] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. Furthermore, within the scope of the gist of the present application, various modifications that can be thought of by those skilled in the art, other modes constructed by combining part of the configuration elements of the embodiments are also included in the scope of the present application.

Claims

1. A battery cell comprising an electrode assembly, the electrode assembly comprising a positive electrode tab, a negative electrode tab, and a separator film between the positive electrode tab and the negative electrode tab; the negative electrode tab comprising a negative electrode current collector and a negative electrode active layer on at least one side of the negative electrode current collector, the negative electrode active layer comprising a negative electrode material, the negative electrode material comprising a negative electrode active material, the negative electrode active material comprising graphite; the positive electrode tab comprising a positive electrode current collector and a positive electrode active layer on at least one side of the positive electrode current collector, the positive electrode active layer comprising a positive electrode material, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising a lithium iron phosphate material and a lithium manganese iron phosphate material; The battery cell has a surface density of the positive electrode active layer of 200-370 mg / 1540.25 mm 2 at 100% SOC state, and a compaction density of the positive electrode active layer of 2.27-2.67 g / cm 3 .

2. The battery cell of claim 1, wherein, The battery cell has a surface density of the positive electrode active layer of 240-340 mg / 1540.25 mm in a 100% SOC state 2 .

3. The battery cell of claim 1 or 2, wherein, The battery cell has a compaction density of the positive electrode active layer of 2.40-2.67 g / cm3 in a 100% SOC state 3 .

4. The battery cell of any one of claims 1 to 3, wherein, The compaction density of the negative active layer of the battery cell is 1.04-1.48 g / cm 3 , and optionally 1.23-1.42 g / cm 3 .

5. The battery cell of any one of claims 1 to 4, wherein, The battery cell has a surface density of the negative electrode active layer of 79-170 mg / 1540.25 mm in a 100% SOC state 2 , optionally 100-155 mg / 1540.25 mm 2 .

6. The battery cell of any one of claims 1 to 5, wherein, a mass percentage of manganese element is 2.1%-25% based on a mass of the positive electrode material.

7. The battery cell of any one of claims 1 to 6, wherein, the positive electrode active material further comprises one or more elements of 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, Hf, Ni, Co, Ru, Ag, Pb.

8. The battery cell of any one of claims 1 to 7, wherein, The powder compaction density of the positive electrode material under 30000N is 2.3-2.7g / cm 3 , optionally 2.43-2.6g / cm 3 .

9. The battery cell of any one of claims 1 to 8, wherein, The BET specific surface area of the positive electrode material is 7.5-16 m 2 / g.

10. The battery cell of any one of claims 1 to 9, wherein, a volume average particle size Dv50 of the positive electrode material is 0.35-2 μm, optionally 0.35-1.2 μm.

11. The battery cell of any one of claims 1 to 10, wherein, a mass ratio of the lithium iron phosphate material to the lithium manganese iron phosphate material is 1:9-9:1, optionally 3:7-7:

3.

12. The battery cell of any one of claims 1-11, wherein, the positive electrode active material further comprises carbon; optionally, a mass percentage of the carbon is 1%-3% based on a mass of the positive electrode material.

13. The battery cell of any one of claims 1-12, wherein, the positive electrode tab further comprises a positive electrode conductive layer, the positive electrode conductive layer being disposed between the positive electrode current collector and the positive electrode active layer.

14. The battery cell of claim 13, wherein, a thickness of the positive electrode conductive layer is 0.5-2 μm.

15. The battery cell of claim 13 or 14, wherein, the positive electrode conductive layer comprises one or more of a positive electrode conductive agent, a positive electrode binder.

16. The battery cell of claim 15, wherein one or more of the following: the positive electrode conductive agent comprises one or more of super conductive carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers; the positive electrode conductive agent at least comprises super conductive carbon and carbon nanotubes; the positive electrode binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, and fluorine-containing acrylic ester resin.

17. The battery cell of claim 15 or 16, wherein, a mass percentage of the positive electrode conductive agent is 30%-50% based on a mass of the positive electrode conductive layer; and / or, a mass percentage of the positive electrode binder is 50%-70% based on a mass of the positive electrode conductive layer.

18. The battery cell of any one of claims 1-17, wherein, The chemical formula of the lithium iron phosphate material is Li x Fe (1-s) M s P y O z wherein x is greater than or equal to 0.5 and less than or equal to 1.3, s is greater than or equal to 0 and less than 1, y is greater than or equal to 0.5 and less than or equal to 1.3, z is greater than or equal to 3 and less than or equal to 5, M includes one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb; and / or, The chemical formula of the lithium iron manganese phosphate material is Li x Fe (1-t-s) Mn t M s P y O z , wherein x is greater than or equal to 0.5 and less than or equal to 1.3, t is greater than 0 and less than 1, s is greater than or equal to 0 and less than 1, 1-t-s is greater than 0 and less than 1, y is greater than or equal to 0.5 and less than or equal to 1.3, z is greater than or equal to 3 and less than or equal to 5, and M includes one or more elements selected from 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, Hf, Ni, Co, Ru, Ag, Pb.

19. The battery cell of any one of claims 1-18, wherein, The positive electrode active layer further comprises a lithium supplement agent, the lithium supplement agent comprising one or more of lithium nickel cobalt manganese oxide, lithium ferrite, lithium nickelate, lithium cobaltate, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium metavanadate, lithium tartrate, lithium citrate, lithium oxide, lithium fluoride, lithium sulfide, lithium nitride; optionally, the lithium ferrite in the lithium supplement agent is lithium-rich lithium ferrite; optionally, the lithium nickelate in the lithium supplement agent is lithium-rich lithium nickelate.

20. The battery cell of any one of claims 1-19, wherein, The negative electrode tab further comprises a negative electrode conductive layer, the negative electrode conductive layer being arranged between the negative electrode current collector and the negative electrode active layer.

21. The battery cell of claim 20, wherein, The thickness of the negative electrode conductive layer is 0.5-2 μm.

22. The battery cell of claim 20 or 21, wherein, The negative electrode conductive layer comprises one or more of a negative electrode conductive agent, a negative electrode binder.

23. The battery cell of claim 22, wherein, The negative electrode conductive agent comprises one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers; and / or, The negative electrode binder comprises one or more of styrene-butadiene rubber, water-soluble unsaturated resin, water-based acrylic resin, polyvinyl alcohol, sodium alginate, carboxymethyl chitosan.

24. The battery cell of claim 22 or 23, wherein, The mass percentage content of the negative electrode conductive agent is 20%-40% based on the mass of the negative electrode conductive layer; and / or, The mass percentage content of the negative electrode binder is 60%-80% based on the mass of the negative electrode conductive layer.

25. The battery cell of any one of claims 1-24, wherein, The negative electrode active layer is a single-layer or multi-layer structure, and the volume average particle size Dv50 of the negative electrode active material in the negative electrode active layer is 7.5-19.5 μm.

26. The battery cell of any one of claims 1-25, wherein, The negative electrode active layer is a single-layer structure, and the volume average particle size Dv50 of the negative electrode active material is 8.0-17.5 μm.

27. The battery cell of any one of claims 1-27, wherein, The negative electrode active layer comprises a first negative electrode active layer close to the negative electrode current collector and a second negative electrode active layer arranged on the first negative electrode active layer.

28. The battery cell of claim 27, wherein, The thickness ratio of the second negative electrode active layer to the first negative electrode active layer is 2:8-8:

2.

29. The battery cell of claim 27 or 28, wherein, The volume average particle size Dv50 of the negative electrode active material in the first negative electrode active layer is 7.5-19.5 μm, and optionally 12.5-18.5 μm.

30. The battery cell of any one of claims 27-29, wherein, The volume average particle size Dv50 of the negative electrode active material in the second negative electrode active layer is 7.5-19.5 μm, and optionally 7.5-15.5 μm.

31. The battery cell of any one of claims 27-30, wherein, The volume average particle size Dv50 of the negative electrode active material in the second negative electrode active layer is smaller than the volume average particle size Dv50 of the negative electrode active material in the first negative electrode active layer.

32. The battery cell of any one of claims 27-31, wherein, The graphite in the first negative electrode active layer and the second negative electrode active layer is independently selected from one or more of natural graphite, composite graphite.

33. The battery cell of claim 32, wherein, The composite graphite comprises a body and a coating layer coated on the surface of the body; the body comprises artificial graphite, and the coating layer comprises amorphous carbon.

34. The battery cell of claim 32 or 33, wherein, The composite graphite comprises secondary particles.

35. The battery cell of any one of claims 32-34, wherein, The powder resistivity of the composite graphite under 8 MPa is 0.01-0.04 Ω·cm.

36. The battery cell of any one of claims 32-35, wherein, The powder compaction density of the composite graphite under 20000N pressure is 1.5-1.85g / cm 3 , and optionally 1.55-1.75g / cm 3 .

37. The battery cell of any one of claims 1-36, wherein, The charge gram capacity of the negative electrode material at 0.1 C rate is 350-550 mAh / g.

38. The battery cell of any one of claims 1-37, wherein, The negative electrode active material further comprises a silicon material.

39. The battery cell of claim 38, wherein, The silicon material comprises one or more of a silicon oxide compound and a silicon carbon compound; and / or, The mass percentage of the silicon element is 0.3%-10%, or 1%-6%, based on the mass of the negative electrode material.

40. The battery cell of any one of claims 1-39, wherein, The battery cell further comprises an electrolyte, and the electrolyte has an electrical conductivity of 10-20 mS / cm, or 12-17 mS / cm, at room temperature.

41. The battery cell of any one of claims 1-40, wherein, The battery cell further comprises a separator film, and the separator film comprises a porous base film and a functional film layer arranged on at least one side of the porous base film.

42. The battery cell of claim 41, wherein, The thickness of the porous base film is 5-7 μm; and / or, The porosity of the porous base film is 20%-70%, or 30%-50%.

43. The battery cell of claim 41 or 42, wherein, The functional film layer comprises a first functional film layer and a second functional film layer arranged on two sides of the porous base film, respectively, the first functional film layer comprises inorganic material particles, and the second functional film layer comprises composite particles, the composite particles comprising non-fluoropolymer particles and inorganic material particles attached to surfaces of the non-fluoropolymer particles or located in the non-fluoropolymer particles.

44. The battery cell of any one of claims 1-43, wherein, The thickness of the positive electrode current collector is 9-17 μm; and / or, The thickness of the negative electrode current collector is 4.5-8 μm.

45. The battery cell of any one of claims 1-44, wherein, The injection coefficient of the battery cell is 2.4-3.1 g / Ah.

46. The battery cell of any one of claims 1-45, wherein, The volumetric energy density of the battery cell is 400-550 Wh / L, or 430-500 Wh / L. 47.A battery device comprising the battery cell of any one of claims 1 to 46; the battery device comprising a battery module, a battery pack or an energy storage device. 48.A power utilization device comprising the battery cell of any one of claims 1 to 46 or the battery device of claim 47.

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