Battery cell, battery device and power-consuming device

Abstract

Battery cell, characterized in that it comprises an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, wherein the separating film is located between the cathode foil and the anode foil, and wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, wherein the cathode film layer comprises an active cathode material, wherein the active cathode material comprises lithium-containing phosphate with an olivine structure, where the one-sided coating weight of the cathode film layer is 180 mg / 1540.25 mm² 2 up to 380mg / 1540.25 mm 2 amounts; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises an active anode material, wherein the active anode material comprises a silicon-based material, wherein the mass fraction of silicon is 0.3% to 10.0% relative to the mass of the active anode material; wherein the electrolyte solution comprises a first additive, wherein the first additive comprises at least one of ethylene carbonate and ethylene carbonate derivatives, and wherein the mass fraction of the first additive is 1% to 12% based on the total mass of the electrolyte solution, wherein the ethylene carbonate derivative comprises a compound represented by formula I: wherein R1, R2, R3 and R4 each independently comprise one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R1, R2, R3 and R4 are not simultaneously hydrogen atoms.

Description

TECHNICAL AREA

[0001] The present application relates to a battery cell, a battery device and a power-consuming device. STATE OF THE ART

[0002] Lithium-ion batteries are characterized by properties such as high capacity and long lifespan, making them widely used in electronic devices like mobile phones, laptops, e-bikes, electric vehicles, electric aircraft, electric ships, and power tools. As the applications of lithium-ion batteries expand, so do the demands on their performance characteristics, such as fast charging capability and energy density. CONTENT OF THE PRESENT INVENTION

[0003] In view of the problems mentioned above, the present application provides a battery cell, a battery device and a power-consuming device that can improve the energy density of the battery cell while achieving a balance between good cycle performance and fast charging capability.

[0004] In a first aspect, the present application provides a battery cell comprising an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, the separating film being located between the cathode foil and the anode foil. and wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, and wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises lithium-containing phosphate with an olivine structure, and wherein the one-sided coating weight of the cathode film layer is 180mg / 1540.25 mm 2 up to 380mg / 1540.25 mm 2 amounts; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises an active anode material, wherein the active anode material comprises a silicon-based material, and wherein, based on the mass of the active anode material, the mass fraction of silicon is 0.3% to 10.0%; wherein the electrolyte solution comprises a first additive, wherein the first additive comprises at least one of ethylene carbonate and ethylene carbonate derivatives, and wherein the mass fraction of the first additive is 1% to 12% based on the total mass of the electrolyte solution, and wherein the ethylene carbonate derivative comprises a compound represented by formula I: wherein R1, R2, R3 and R4 each independently comprise one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R1, R2, R3 and R4 are not simultaneously hydrogen atoms.

[0005] In the present application, the active cathode material of the battery cell comprises lithium-containing phosphate with an olivine structure, exhibiting excellent structural stability. By matching a high-density cathode film layer to an anode film layer containing a specific amount of silicon, the energy density of the battery cell is increased while simultaneously and effectively improving its fast-charging capability. At the same time, the incorporation of a first additive comprising ethylene carbonate and / or vinyl carbonate derivatives into the electrolyte solution of the battery cell, with the mass fraction of the first additive being kept within a suitable range, facilitates the formation of a SEI film with a suitable thickness and improved flexibility and stability at the silicon-containing anode interface.This ensures that the silicon-containing anode interface maintains both excellent stability and low impedance, resulting in a battery cell with high energy density, superior fast-charging capability, and good cycle performance.

[0006] In summary, the present application achieves a balance between the fast-charging capability, the cycle performance, and the energy density of the battery cell by synergistically controlling the following parameters within suitable ranges: the one-sided coating weight of the cathode layer, the mass fraction of silicon in the active anode material, the inclusion of lithium-containing phosphate with an olivine structure in the active cathode material, and the type and mass fraction of the additives in the electrolyte solution.

[0007] In each embodiment, the mass fraction of the silicon element is 0.3% to 6.0%, relative to the mass of the active anode material.

[0008] By maintaining a suitable mass fraction of silicon in the silicon-based material, not only can the energy density of the battery cell be increased, but the impact of excessive silicon on the battery cell's cycle performance can also be reduced. Thus, both the energy density and the cycle performance of the battery cell are equally considered.

[0009] In each embodiment, at least one of R1, R2, R3 and R4 comprises a fluorine atom.

[0010] The carbonate ester derivative, in which at least one of R1, R2, R3, and R4 is a fluorine atom, readily undergoes ring opening to form an SEI film on the anode surface containing a higher proportion of organic substances. This facilitates improved overall flexibility of the SEI film, thereby enhancing the stability of the SEI film and the anode interface during the cycle and increasing the cycle performance of the battery cell.

[0011] In each embodiment, the ethylene carbonate derivative comprises one or more of the group consisting of fluorinated ethylene carbonate, difluoroethylene carbonate and trifluoromethylethylene carbonate.

[0012] Suitable ethylene carbonate derivative additives can form an SEI film on the anode side, containing a higher proportion of organic substances. This increases the overall flexibility of the SEI film, thereby improving the stability of the SEI film and the anode interface during the cycle and enhancing the cycle performance of the battery cell. Simultaneously, the SEI film, formed with the involvement of fluorinated ethylene carbonate, difluoroethylene carbonate, and trifluoromethylethylene carbonate, exhibits low impedance, which also contributes to improving the fast-charging capability of the battery cell.

[0013] In each embodiment, the battery cell fulfills the following relationship: 0.025≤A / B≤6, optional 0.035A / B≤2.5, where A represents the mass fraction of the silicon element relative to the mass of the active anode material; B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution.

[0014] The ratio of silicon mass fraction in the active anode material to the mass fraction of the first additive in the electrolyte solution, maintained within a suitable range, enables a synergistic interaction between the silicon element in the anode and the first additive. This improves the energy density of the battery cell and also affects the battery cell's cycle performance.

[0015] In each embodiment, the mass fraction of the silicon element in the active anode material is 0.3% to 3%, relative to the mass of the active anode material. where, based on the total mass of the electrolyte solution, the mass fraction of the first additive is 2% to 7.5%.

[0016] In systems with relatively low silicon content, SEI film degradation during the battery cell cycle is comparatively low. By controlling the mass fraction of the first additive within a suitable range, the formation of an SEI film with an appropriate thickness is facilitated. This improves the stability of the SEI film and the anode interface, enhancing the battery cell's cycle performance while simultaneously achieving low anode interface impedance. This is advantageous for improving the battery cell's fast-charging capability and is better suited for application scenarios with higher demands on both cycle performance and fast charging.

[0017] In each embodiment, the mass fraction of the silicon element in the active anode material is greater than 3% and less than or equal to 6%, relative to the mass of the active anode material; where, relative to the total mass of the electrolyte solution, the mass fraction of the first additive is 3% to 10%.

[0018] In systems with a relatively high silicon content, the SEI film is subject to greater degradation during the battery cell cycle. By controlling the mass fraction of the first additive within a suitable range, the formation of an SEI film with an appropriate thickness is facilitated. This improves the stability of the SEI film and the anode interface, and thus the cycle performance of the battery cell. This is better suited for application scenarios with higher demands on cycle performance and energy density of the battery cell.

[0019] In each embodiment, the lithium-containing phosphate comprises an olivine structure: a lithium-containing phosphate matrix, and A coating layer located on at least part of the surface of the lithium-containing phosphate matrix, wherein the coating layer contains a carbon element. The lithium-containing phosphate with an olivine structure comprises a carbon coating layer, which improves the electrical conductivity of the material and thus enables improved fast-charging capability of the battery cell.

[0020] In each embodiment, the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure is 0.8% to 2.3%.

[0021] Controlling the mass fraction of the carbon element in the coating layer within a suitable range not only improves the conductivity of the material and the fast-charging capability of the battery, but also balances the gram-specific capacity of the material, thus taking into account both the fast-charging capability and the energy density of the battery cell.

[0022] In each embodiment, the battery cell satisfies the following relationship: 0.08≤C / B≤1.15, where C represents the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure; where B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution.

[0023] By controlling the mass fraction of the carbon element in the lithium-containing phosphate with an olivine structure and the mass fraction of the first additive in the electrolyte solution within a suitable range, the electrical conductivity of the material is improved and the fast-charging capability of the battery cell is increased. Simultaneously, the cycle stability of the material is enhanced and the cycle performance of the battery cell is improved.

[0024] In each embodiment, the coating layer further comprises a substance Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1 , where 0≤d1≤1, 3≤m1≤5 and 2≤n1≤4 hold; wherein M3 comprises one or more of the elements Ti, Zr, Hf, Ge or Sn, wherein M3 optionally has a valency of +4.

[0025] The coating layer includes the compound Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1, which exhibits excellent ionic conductivity. This significantly improves the lithium ion ejection / insertion rate, enhances the overall ionic conductivity of the material, and thus facilitates improved fast-charging capability of the battery.

[0026] In each embodiment, the lithium-containing phosphate matrix comprises a compound of the general formula Li x1 A y1 Me a1 M b1 P1 -c1 X c1 Y z1 , where 0.5≤x1≤1.3, 0≤y1≤1.3, 0.9≤x1+y1≤1.3, 0.9≤a1≤1.5, 0≤b1≤0.5, 0.9≤a1+b1≤1.5, 0≤c1≤0.5 and 3≤z1≤5 hold. where A includes at least one of Na, K and Mg; Me includes at least one of Mn, Fe, Co and Ni; M includes at least one 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; X includes at least one of S, Si, Cl, B, C, N, P; Y includes at least one of O, F.

[0027] In each embodiment, the lithium-containing phosphate matrix comprises one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium nickel phosphate, lithium cobalt phosphate and modified forms of one of the aforementioned substances, wherein the modified forms comprise one or more doping modifications and coating modifications.

[0028] In each embodiment, the powder density of the active cathode material at 30,000 N is 2.43 g / cm³. 3 up to 2.85 g / cm³ 3 , optional 2.48 g / cm² 3 up to 2.80 g / cm³ 3 .

[0029] If the powder density of the active cathode material is within the aforementioned range at 30,000 N, the energy density of the battery cell increases. Furthermore, since the active cathode material can be packed more densely within the cathode layer, the contact resistance between the particles is reduced, which further lowers the resistance of the electrode foil and improves the fast-charging capability of the battery cell.

[0030] In each embodiment, the density of the cathode film layer at a battery cell charge level of 100% is 2.50 g / cm³. 3 up to 2.80 g / cm³ 3 .

[0031] Within this suitable range of cathode film layer density, the battery cell exhibits a high energy density.

[0032] In each embodiment, the active anode material comprises a carbon-based material, wherein the carbon-based material comprises graphite.

[0033] The graphite exhibits excellent electrical conductivity and cycle stability, thereby improving the fast charging capability and cycle performance of the battery cell.

[0034] In each embodiment, the graphite comprises composite graphite particles, wherein the composite graphite particles comprise graphite base particles and a carbon coating layer encasing the surface of the graphite base particles, wherein the graphite base particles comprise secondary particles, while the carbon coating layer comprises amorphous carbon.

[0035] The secondary particles exhibit excellent ion transport properties, facilitating the insertion and removal of lithium ions while simultaneously improving the material's ionic conductivity. Additionally, the carbon coating layer, which comprises amorphous carbon, enhances the electrical conductivity of the composite graphite particles. Together, the secondary particles in the core and the amorphous carbon coating layer improve the material's electron and ionic conductivity, thus contributing to improved fast-charging capability of the battery cell.

[0036] In each embodiment, the composite graphite particles meet at least one of the following conditions: (1) the mass fraction of amorphous carbon is 2% to 5% in relation to the total mass of the composite graphite particles; (2) the powder resistance of the composite graphite particles is 0.005 Ω·cm to 0.04 Ω·cm.

[0037] By controlling the mass fraction of amorphous carbon in the composite graphite particles to a suitable range, the electrical conductivity of the material is improved, thereby improving the fast charging capability of the battery.

[0038] The composite graphite particles exhibit low powder resistance and excellent electrical conductivity, which contributes to improving the fast-charging capability of the battery cell.

[0039] In each embodiment, a first anode film layer and a second anode film layer are present, wherein the first anode film layer is arranged between the current collector and the second anode film layer, and wherein the first anode film layer and the second anode film layer each comprise the composite graphite particles.

[0040] In each embodiment, the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is greater than or equal to the volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer.

[0041] During fast charging of the battery cell, the overvoltage of the second anode film layer, which faces away from the current collector, is typically higher. The primary bottleneck in the anode film layer, which impairs the fast-charging capability of the battery cell, is located in the second anode film layer. The present application controls the particle size of the composite graphite particles in the second anode film layer so that it is relatively smaller, thereby shortening the lithium-ion transport path, improving the lithium-ion transport performance of the second anode film layer, and enhancing the fast-charging capability of the battery cell.

[0042] In each embodiment, the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is 8.5 µm to 14.8 µm, and / or The volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer is 7.8 µm to 12.8 µm.

[0043] By controlling the particle size of the composite graphite particles in the first anode film layer and / or the second anode film layer within a suitable range, the lithium ion transport paths in the anode film layer are shortened, thereby improving the fast charging capability of the battery cell.

[0044] In each embodiment, the thickness fraction of the second anode film layer is 30% to 70%, relative to the total thickness of the first anode film layer and the second anode film layer.

[0045] The thickness fraction of the second anode film layer within the suitable range can balance the contribution of the second anode film layer to the fast charging capability of the battery and the contribution of the first anode film layer to the energy density of the battery, resulting in a battery cell with excellent fast charging capability and high energy density.

[0046] In each embodiment, the anode foil further comprises an anode conductive layer located between the anode collector and the anode film layer on at least one side, wherein the anode conductive layer comprises a conductive means, the conductive means comprising one or more from the group consisting of superconducting carbon, conductive graphite, acetylene carbon black, carbon black, ketjen carbon black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0047] By arranging an anode conductive layer, which includes a conductive medium, between the current collector and the anode film layer, the electrical conductivity of the anode foil is improved, thereby improving the fast charging capability of the battery cell.

[0048] In each embodiment, the anode conductive layer has a thickness of 0.5 µm to 2 µm.

[0049] By controlling the thickness of the anode conductive layer within a suitable range, a balance can be achieved between the fast charging capability and the energy density of the battery cell.

[0050] In each embodiment, the density of the anode film layer at a battery cell charge level of 100% is 1.15 g / cm³. 3 up to 1.45 g / cm³ 3 , and / or The one-sided coating weight of the anode film layer is 70mg / 1540.25 mm². 2 up to 135mg / 1540.25 mm 2 .

[0051] Maintaining the one-sided coating weight or the pressure density of the anode film layer within a suitable range contributes to improved fast-charging capability of the battery cell.

[0052] In each embodiment, the electrolyte solution further comprises an organic solvent, wherein the organic solvent comprises one or more of a first organic solvent and a second organic solvent, wherein the first organic solvent comprises at least one of a cyclic carbonate and a chain-like carbonate, optionally being a cyclic carbonate; wherein the second organic solvent comprises R5-COO-R6, wherein R5 comprises one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R6 comprises one from the group consisting of a C1-C5 alkyl and a C1-C5 halogenated alkyl.

[0053] The first organic solvent, which is a cyclic or chain-like carbonate, possesses a relatively high dielectric constant and excellent ionic conductivity, which is beneficial for improving the electrical conductivity of the electrolyte solution. The second organic solvent has a low viscosity, which also contributes to improving the electrical conductivity of the electrolyte solution. The electrolyte solution contains the first and / or the second organic solvent, which contributes to improved lithium ion migration and enhances the fast-charging capability of the battery cell.

[0054] In each embodiment, the cyclic carbonate comprises one or more from the group consisting of ethylene carbonate, propylene carbonate and butylene carbonate; and / or wherein the chain-like carbonate comprises one or more from the group consisting of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; and / or wherein the second organic solvent comprises one or more from the group consisting of methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate and ethyl butyrate.

[0055] In each embodiment, the mass fraction of the first organic solvent is 20% to 72%, based on the total mass of the electrolyte solution.

[0056] A first organic solvent containing suitable amounts of cyclic carbonates and chain-like carbonates can further improve the electrical conductivity of the electrolyte solution, thereby facilitating lithium ion migration and improving the fast-charging capability of the battery cell.

[0057] In each embodiment, the electrolyte solution further comprises a second additive, wherein the second additive comprises one or more from the group consisting of a sulfur-containing additive and a lithium salt additive.

[0058] The sulfur-containing additive and the lithium salt additive are able to improve the interfacial film properties on the cathode side and / or anode side, improve the interfacial chemistry between the cathode and / or anode and the electrolyte solution, and improve the fast charging capability and cycle performance of the battery.

[0059] In each embodiment, the sulfur-containing additive comprises one or more of the following from the group consisting of sulfate vinyl ester, bisulfate vinyl ester, sulfite butene ester, 1,3-propanesulfonic acid lactone, ethylene sulfite and methylenedisulfonic acid methyl ester; and / or

[0060] wherein the lithium salt additive comprises one or more from the group consisting of lithium difluorophosphate, lithium difluorooxalate borate, lithium tetrafluoroborate and lithium dioxalate borate.

[0061] In each embodiment, the electrolyte solution further comprises a lithium salt, wherein the lithium salt comprises one or two from the group consisting of fluorinated sulfonylimide salt and lithium hexafluorophosphate.

[0062] The fluorinated sulfonylimide salt and the lithium hexafluorophosphate readily dissociate, facilitating rapid lithium ion migration and improving the fast-charging capability of the battery cell. Furthermore, the fluorinated sulfonylimide salt and the lithium hexafluorophosphate exhibit relative stability within the electrolyte system, thereby improving the cycle performance of the battery cell.

[0063] In each embodiment, the fluorinated sulfonylimide salt comprises one or two from the group consisting of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)amide.

[0064] In each embodiment, the lithium salt comprises lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate, wherein the molar concentration ratio of lithium bis(fluorosulfonyl)imide to lithium hexafluorophosphate is 0.2 to 1.0.

[0065] In each embodiment, the molar concentration of lithium bis(difluorosulfonyl)imide is 0.2 mol / L to 0.5 mol / L and the molar concentration of lithium hexafluorophosphate is 0.5 mol / L to 1.2 mol / L.

[0066] In each embodiment, the separating film fulfills at least one of the following conditions: (1) the thickness of the separating film is 4 µm to 12 µm, optionally 5 µm to 9 µm; (2) the porosity of the separating film is 20% to 70%, optionally 35% to 60%.

[0067] Within the appropriate thickness range, lithium ions migrate through shorter separation paths via the separating film, thereby reducing the internal resistance of the battery cell and improving the fast charging capability of the battery cell.

[0068] Within the appropriate porosity range, the migration rate of lithium ions through the separating film increases, thereby further reducing the internal resistance of the battery cell and improving the fast charging capability of the battery cell.

[0069] In each embodiment, the battery cell is configured to have a charging time of 5 to 10.5 minutes from a state of charge of 10% to a state of charge of 80%.

[0070] The battery cell has a high charging speed and excellent fast-charging capability.

[0071] In each embodiment, the volumetric energy density of the battery cell is 395 Wh / L to 530 Wh / L.

[0072] In a second aspect, the present application provides a battery device comprising a battery cell in the first aspect.

[0073] In each embodiment, the battery device is configured to have a charging time of 5 to 10.5 minutes from a charge level of 10% to a charge level of 80%.

[0074] The battery device has a high charging speed and excellent fast-charging capability.

[0075] In a third aspect, the present application provides a power-consuming device, comprising a battery device in the second aspect. BRIEF DESCRIPTION OF THE DRAWING

[0076] To clarify the technical solution in the embodiments of the present application, the accompanying drawings used in these embodiments are briefly described below. Obviously, the accompanying drawings described below represent some embodiments of the present application. A person skilled in the art in this field could derive other drawings from the accompanying drawings, provided that no creative work is undertaken. Fig. Figure 1 shows a schematic diagram of a battery cell in an embodiment of the present application; Fig. Figure 2 shows an exploded view of a battery cell in an embodiment of the present application according to Fig. 1; Fig. Figure 3 shows a schematic diagram of a battery module in an embodiment of the present application; Fig. Figure 4 shows a schematic diagram of a battery pack in an embodiment of the present application; Fig. Figure 5 shows an exploded view of a battery pack in an embodiment of the present application according to Fig. 4; Fig. Figure 6 shows a schematic diagram of a power-consuming device in an embodiment of the present application which uses a battery cell as a power source. DETAILED DESCRIPTION

[0077] In conjunction with the accompanying drawings in the embodiment of the present invention, the technical solutions in this embodiment are explained clearly and completely below. Obviously, the embodiments described do not represent all embodiments, but only a subset of them. All other embodiments that a person skilled in the art in this field could obtain from the embodiments in the present invention without any creative work shall be considered to be covered by the scope of protection of the present invention.

[0078] The following section, with reference to the accompanying drawings, describes in detail a battery, a battery filling method, an electrolyte solution and a manufacturing method thereof, and a current-consuming device of the present application. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure are omitted. This is to prevent the following description from becoming unnecessarily long and to facilitate understanding by the person skilled in the art. Furthermore, the accompanying drawings and the following description serve to ensure the complete understanding of the present application by the person skilled in the art and are not intended to limit the subject matter specified in the claims.

[0079] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60-120 and 80-110 is specified for a particular parameter, a range of 60-110 and 80-120 is also to be expected. Furthermore, if the minimum values ​​1 and 2 and the maximum values ​​3, 4, and 5 are specified, the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0080] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined with one another.

[0081] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined.

[0082] Unless expressly stated otherwise, all steps of the present application may be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the method may also include step (c) means, for example, that step (c) may be added to the method in any order; e.g., 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).

[0083] With the continuous expansion of applications for lithium-ion batteries, the demands on their energy density and fast-charging capability are also increasing. To increase the battery's energy density, the coating area density of the cathode and anode film layers is typically increased. However, increasing the coating area density of these layers lengthens the lithium-ion migration paths, which increases the battery's internal resistance. This, in turn, impairs the battery's fast-charging capability. In particular, a high coating area density of the anode film layer significantly reduces the fast-charging capability of the battery cell. Simply adjusting the coating weight of the cathode and anode makes it difficult to achieve a balance between energy density and fast-charging capability.

[0084] In light of the aforementioned problems, the present application employs a rational design of the battery cell system to achieve a balance between energy density and fast-charging capability. In particular, the energy density is improved while simultaneously achieving a balance between fast-charging capability and the battery's cycle performance through the appropriate combination of the cathode foil coating area density, the silicon content of the anode material, and the additives in the electrolyte solution. [Battery cell]

[0085] The battery cell comprises an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, the separating film being located between the cathode foil and the anode foil. and wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, and wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises lithium-containing phosphate with an olivine structure, and wherein the one-sided coating weight of the cathode film layer is 180mg / 1540.25 mm 2 up to 380mg / 1540.25 mm 2 amounts; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises an active anode material, wherein the active anode material comprises a silicon-based material, and wherein, based on the mass of the active anode material, the mass fraction of silicon is 0.3% to 10.0%; wherein the electrolyte solution comprises a first additive, wherein the first additive comprises at least one of ethylene carbonate and ethylene carbonate derivatives, and wherein the mass fraction of the first additive is 1% to 12% based on the total mass of the electrolyte solution, and wherein the ethylene carbonate derivative comprises a compound represented by formula I: wherein R1, R2, R3 and R4 each independently comprise one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R1, R2, R3 and R4 are not simultaneously hydrogen atoms.

[0086] In some embodiments, the one-sided coating weight of the cathode film layer is 180 mg / 1540.25 mm². 2 up to 380mg / 1540.25 mm 2 For example, the one-sided coating weight of the cathode film layer is 180 mg / 1540.25 mm². 2 , 190 mg / 1540.25 mm 2, 200 mg / 1540.25 mm 2 , 210 mg / 1540.25 mm 2 , 220 mg / 1540.25 mm 2 , 230 mg / 1540.25 mm 2 , 240 mg / 1540.25 mm 2 , 250 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm 2 , 270 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 290 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 , 310 mg / 1540.25 mm 2 , 320 mg / 1540.25 mm 2 , 330 mg / 1540.25 mm 2 , 340 mg / 1540.25 mm 2 , 350 mg / 1540.25 mm 2 , 360 mg / 1540.25 mm 2 , 370 mg / 1540.25 mm 2 , 380 mg / 1540.25 mm 2 or a value within a range formed by any two of these values.

[0087] In an example relating to the embodiment of the present application, the one-sided coating area density of the cathode film layer in the battery cell can be tested using the following method: For example, a one-sided coated cathode foil (in the case of a double-sided coated electrode foil, the cathode film layer of one side can be wiped off first) is taken, punched, and cut into a small disc with an area of ​​S1, weighed, and recorded as M1, with the thickness measured as H1. Then, the cathode film layer of the cathode foil, which was weighed as described above, is wiped off, and the weight of a cathode collector is weighed and recorded as M0, and the thickness H0 is measured. The one-sided coating weight of the cathode film layer = (weight of the cathode foil M1 - weight of the cathode collector M0) / S1.

[0088] In one embodiment of the present application, the silicon-based material can comprise at least one from the group consisting of elemental silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloy materials. Here, elemental silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloy materials can refer to silicon-based materials or to the form of silicon present in the anode film of a battery after formation. The silicon oxide SiOx, where 0 < x ≤ 2, is used because silicon atoms in the anode film layer can be bonded to oxygen atoms in various ways, including at least one from the group consisting of SiO₂, SiO₃, and SiO₄. 1,2, SiO2 and other possible silicon oxides. The silicon-carbon complexes can refer to the form of silicon present in the anode foil of a battery after its formation. Silicon-carbon complexes can also be formed by chemical reactions between silicon and carbon elements within the battery cell. Alternatively, they can result from the physical mixing of elemental silicon and elemental carbon; for example, elemental carbon may comprise a porous framework in whose pores or on whose surface elemental silicon is located. The silicon-carbon complexes may further comprise carbon layers covering the surface of elemental silicon.

[0089] In some embodiments, the mass fraction of the silicon element is 0.3% to 10.0%, relative to the mass of the active anode material. For example, the mass fraction of the silicon element is 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8%, 10% or a value within a range formed by any two of these values.

[0090] The qualitative and quantitative determination of each substance or element in the present application can be carried out using suitable equipment and procedures known to a person skilled in the art. Relevant testing procedures may refer to national and international testing standards, national and international company standards, etc. Furthermore, a person skilled in the art may adjust certain test steps / equipment parameters with regard to test accuracy in order to obtain more precise results. A single testing procedure may be used for the qualitative or quantitative analysis, or several procedures may be combined for such determinations.

[0091] For example, the mass fraction of silicon in the anode film layer is of well-known importance in this field. Testing can be performed using generally accepted equipment and procedures, such as immersing the anode foil in a solvent (e.g., water) to separate the active anode material from the anode collector, followed by filtration to obtain the various substances within the anode film layer. These are then used as test samples. The test samples are analyzed using the Thermo Fisher Scientific ICAP7400 inductively coupled plasma emission spectrometer according to standards GB / T30902-2014 to determine the silicon content.

[0092] In some embodiments, the mass fraction of the first additive is 1% to 12% relative to the total mass of the electrolyte solution; for example, the mass fraction of the first additive is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% or a value within a range formed by any two of these values.

[0093] The type and concentration of the first additive in the electrolyte solution can be determined by electrolyte analysis using methods known to those skilled in the art. For example, the composition of the electrolyte solution can be determined by liquid chromatography, ultraviolet spectrophotometry, or ultraviolet visible spectrophotometry. To test the concentration of inorganic substances in the electrolyte solution using an ion chromatograph (IC), for instance, a quantitative volume of the electrolyte solution (with a dilution concentration in the middle of the standard curve) is weighed, diluted with ultrapure water to a final volume of 100 ml, and then subjected to an automated autosampling test by the ion chromatograph.The resulting chromatogram of inorganic ions is analyzed. Based on the peak positions of the chromatogram, the types of corresponding inorganic substances are compared, and the percentage of ions of the corresponding inorganic substances is calculated based on the peak area. The aforementioned free electrolyte solution is diluted 3- to 10-fold with acetonitrile to obtain the electrolyte dilution solution for the test. A complete qualitative analysis of the electrolyte dilution solution is performed in the instrument using the GC-MS 3100 gas chromatograph for organic components, with the injector temperature set at 250°C and the scan range at 35 µm to 270 µm. Upon completion of the test, the total ion chromatogram for each organic substance is obtained.The types of corresponding organic substances are compared according to the peak positions of the chromatogram, and the percentage content of each organic substance is calculated based on the peak area. The mass fraction of the first additive in the battery cell electrolyte solution is determined by dividing the calculated mass of the first additive by the mass of the electrolyte solution sample. It is understood that the mass fraction of the first additive in the battery cell electrolyte solution is slightly lower than the mass fraction of the first additive added to the battery cell electrolyte solution.

[0094] In the description, the term "halogen atom" includes one or more from the group consisting of fluorine atom, chlorine atom, bromine atom and iodine atom.

[0095] In this description, the term "C1-C5 alkyl" refers to a straight-chain or branched hydrocarbon group consisting exclusively of carbon and hydrogen atoms, exhibiting no unsaturation, containing one to five carbon atoms, and bonded to the rest of the molecule via a single bond. Examples include methyl, ethyl, propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl.

[0096] In the description, the term "C1-C5 halogenated alkyl" refers to a C1-C5 alkyl in which at least one hydrogen atom is substituted by a halogen atom, including but not limited to: -CF3, -CF2CH2, -CF2CH2CH3, -CF2CF2CH2CH3, -CF2CH2CH2CH2CH3.

[0097] The present application achieves improved fast-charging capability of the battery cell by aligning a high-density cathode film layer with a silicon-containing anode film layer. This approach increases the energy density of the battery cell while simultaneously reducing the coating weight of the anode film layer. Furthermore, controlling the silicon content in the anode film layer within a suitable range improves the energy density of the battery cell while also considering the battery cell's cycle performance. However, the introduction of silicon-containing materials into the active anode material leads to significant volume expansion and contraction during the battery cell's charge and discharge cycles. This readily damages the SEI film on the anode side and exposes new interfaces where the electrolyte solution continues to undergo reduction reactions.This consumes both the electrolyte solution and active lithium, impairing the cycle and storage performance of the battery cell. To solve this problem, the present application introduces a first additive comprising ethylene carbonate and / or an ethylene carbonate derivative into the electrolyte solution. The ethylene carbonate and the ethylene carbonate derivative preferentially participate in the formation of the SEI film on the anode side compared to other components in the electrolyte solution. In the film formed by the ethylene carbonate and the ethylene carbonate derivative, the organic substances have a higher content, which improves the overall flexibility of the SEI film. This improves the stability of the SEI film and the anode interface during the cycle, reduces reactions between the active anode material and the electrolyte solution, decreases lithium ion consumption, and improves the cycle and storage performance of the battery cell.Furthermore, controlling the mass fraction of the first additive within a suitable range not only improves the flexibility and stability of the SEI film but also regulates its thickness. This simultaneously achieves stability at the anode interface and low impedance, thus benefiting both the cycle performance and fast-charging capability of the battery cell. Additionally, the active cathode material comprises lithium-containing phosphate with an olivine structure, which exhibits excellent structural stability and further enhances the battery cell's cycle performance.

[0098] In summary, the present application achieves a balance between the fast-charging capability, the cycle performance, and the energy density of the battery cell by synergistically controlling the following parameters within suitable ranges: the one-sided coating weight of the cathode layer, the mass fraction of silicon in the active anode material, the inclusion of lithium-containing phosphate with an olivine structure in the active cathode material, and the type and mass fraction of the additives in the electrolyte solution. [Anode foil]

[0099] The anode foil comprises an anode collector and an anode film layer arranged on at least one surface of the anode collector and comprising an active anode material. For example, the anode collector has two surfaces opposite each other in its own thickness direction, with the anode film layer arranged on one or both of the two opposite surfaces of the anode collector.

[0100] In some embodiments, the mass fraction of the silicon element, relative to the mass of the active anode material, is 0.3% to 6.0%, optionally 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6% or a value within a range formed by any two of these values.

[0101] By maintaining a suitable mass fraction of silicon in the silicon-based material, not only can the energy density of the battery cell be increased, but the impact of excessive silicon on the battery cell's cycle performance can also be reduced. Thus, both the energy density and the cycle performance of the battery cell are equally considered.

[0102] In some embodiments, the battery cell satisfies the following relationship: 0.025≤A / B≤6, optionally 0.035≤A / B≤2.5, where A represents the mass fraction of the silicon element relative to the mass of the active anode material; B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution.

[0103] In some embodiments, A / B is optionally 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.1, 0.2, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 or a value within a range formed by any two of these values.

[0104] The ratio of silicon mass fraction in the active anode material to the mass fraction of the first additive in the electrolyte solution, maintained within a suitable range, enables a synergistic interaction between the silicon element in the active anode material and the first additive. This improves the energy density of the battery cell and also takes into account the cycle performance of the battery cell.

[0105] In some embodiments, the mass fraction of the silicon element is 0.3% to 3%, relative to the mass of the active anode material. where, based on the total mass of the electrolyte solution, the mass fraction of the first additive is 2% to 7.5%.

[0106] In some embodiments, the mass fraction of the silicon element in the active anode material is optionally 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3% or a value within a range formed by any two of these values.

[0107] The mass fraction of the first additive in the electrolyte solution is optionally 2%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7%, 7.5% or a value within a range formed by any two of these values.

[0108] In systems with relatively low silicon content, SEI film degradation during the battery cell cycle is comparatively low. By controlling the mass fraction of the first additive within a suitable range, the formation of an SEI film with an appropriate thickness is facilitated. This improves the stability of the SEI film and the anode interface, enhancing the battery cell's cycle performance while simultaneously achieving low anode interface impedance. This is advantageous for improving the battery cell's fast-charging capability and is better suited for application scenarios with higher demands on both cycle performance and fast charging.

[0109] In some embodiments, the mass fraction of the silicon element is greater than 3% and less than or equal to 6%, relative to the mass of the active anode material; where, relative to the total mass of the electrolyte solution, the mass fraction of the first additive is 3% to 10%.

[0110] In some embodiments, the mass fraction of the silicon element in the active anode material is optionally 3.1%, 3.5%, 3.8%, 4.0%, 4.2%, 4.5%, 4.8%, 5.0%, 5.2%, 5.5%, 5.8%, 6.0% or a value within a range formed by any two of these values; wherein the mass fraction of the first additive in the electrolyte solution is optionally 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0% or a value within a range formed by any two of these values.

[0111] In systems with a relatively high silicon content, the SEI film is subject to greater degradation during the battery cell cycle. By controlling the mass fraction of the first additive within a suitable range, the formation of an SEI film with an appropriate thickness is facilitated. This improves the stability of the SEI film and the anode interface, and thus the cycle performance of the battery cell. This is better suited for application scenarios with higher demands on cycle performance and energy density of the battery cell.

[0112] In some embodiments, the active anode material comprises a carbon-based material, wherein the carbon-based material comprises graphite.

[0113] The graphite exhibits excellent electrical conductivity and cycle stability, thereby improving the fast charging capability and cycle performance of the battery cell.

[0114] In some embodiments, the mass fraction of the carbon-based material, relative to the mass of the active anode material, can be greater than or equal to 80% and less than 100%.

[0115] In some embodiments, the graphite comprises composite graphite particles, wherein the composite graphite particles comprise graphite base particles and a carbon coating layer encasing the surface of the graphite base particles, wherein the graphite base particles comprise secondary particles, while the carbon coating layer comprises amorphous carbon.

[0116] Secondary particles refer to particles formed by the aggregation of two or more primary particles.

[0117] In this description, amorphous carbon refers to a transitional carbon material exhibiting a very low degree of graphitization and crystallization and resembling a non-crystalline form (or lacking a fixed shape and periodic structural pattern). In the present application, amorphous carbon refers to the product resulting from the carbonization treatment of an organic carbon source, which has numerous end faces and defects, thus providing ample sites for lithium ions.

[0118] The secondary particles can increase lithium ion migration rates and improve lithium ion transport properties, facilitating the storage and removal of lithium ions while simultaneously enhancing the material's ionic conductivity. Additionally, the carbon coating layer, which includes amorphous carbon, improves the electrical conductivity of the composite graphite particles. Together, the secondary particles in the core and the amorphous carbon coating layer enhance the material's electron and ionic conductivity, thus contributing to improved fast-charging capability of the battery cell.

[0119] In an example relating to the embodiment of the present application, composite graphite particles can be produced using methods known in the art. The production method may, for example, comprise: providing graphite base particles (which may be synthetic graphite) and an organic carbon source; mixing the two; and subjecting the mixture to a carbonization treatment to form a carbon coating layer on at least a part of the surface of the graphite base particles, thereby obtaining the composite graphite particles in the embodiment.

[0120] Optionally, the organic carbon source comprises one or more of coal tar pitch, petroleum pitch, phenolic resin, and coconut shells. Optionally, the organic carbon source may also include petroleum pitch. Optionally, the softening point of the coal tar pitch or petroleum pitch may be below 250°C.

[0121] Optionally, the carbonization treatment temperature is 700°C to 1800°C. Optionally, the carbonization treatment temperature is 1000°C to 1300°C. Within this suitable temperature range, the organic carbon source can be carbonized, and a coating layer comprising amorphous carbon is formed on at least a portion of the surface of the graphite base particles. Optionally, the carbonization treatment duration is 1 to 6 hours.

[0122] In some embodiments, the mass fraction of amorphous carbon is 2% to 5%, optionally 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a value within a range formed by any two of these values, based on the total mass of the composite graphite particles.

[0123] By controlling the mass fraction of amorphous carbon in the composite graphite particles to a suitable range, the electrical conductivity of the material is improved, thereby improving the fast charging capability of the battery.

[0124] In some embodiments, the powder resistance of the composite graphite particles is 0.005 Ω·cm to 0.04 Ω·cm, optionally 0.01 Ω·cm, 0.015 Ω·cm, 0.020 Ω·cm, 0.025 Ω·cm, 0.03 Ω·cm, 0.04 Ω·cm or a value within a range formed by any two of these values.

[0125] In the embodiment of the present application, the powder resistance of the material has a meaning known in this field and can be tested using methods and equipment known in this field, for example by testing in accordance with the test standard GB / T30835-2014 using a powder resistance measuring device PRCD1100.

[0126] The composite graphite particles exhibit low powder resistance and excellent electrical conductivity, which contributes to improving the fast-charging capability of the battery cell.

[0127] In the embodiment of the present application, the anode film layer comprises at least one film layer, which may be a single film layer or at least two film layers. Optionally, the anode film layer comprises at least two film layers.

[0128] When using a single-layer film for the anode film, the active anode material in the anode film comprises graphite and a silicon-based material. Optionally, the active anode material comprises composite graphite particles and a silicon-based material. When using a single-layer film, the volume-averaged particle size Dv50 of the composite graphite particles is 8.2 µm to 13.5 µm. For example, the volume-averaged particle size Dv50 of the composite graphite particles is 8.2 µm, 8.5 µm, 8.8 µm, 9 µm, 9.2 µm, 9.5 µm, 9.8 µm, 10 µm, 10.2 µm, 10.5 µm, 10.8 µm, 11 µm, or a value within a range formed by any two of these values.

[0129] If the anode film layer comprises at least two layers, the active anode material in the anode film layer comprises graphite and a silicon-based material. Optionally, the active anode material comprises composite graphite particles and a silicon-based material, wherein the silicon-based material may be located in at least one or at least two of the two film layers, and the composite graphite particles may be located in at least one or at least two of the two film layers. The anode film layer may comprise two, three, four, or even more film layers.

[0130] In some embodiments, the anode film layer comprises a first anode film layer and a second anode film layer, the first anode film layer being located between the current collector and the second anode film layer. The silicon-based material may be located in the first anode film layer and / or the second anode film layer, while the composite graphite particles may be located in the first anode film layer and / or the second anode film layer.

[0131] The interface between the first anode film layer and the second anode film layer can be regular or irregular, optionally being irregular.

[0132] The anode film layer comprises at least two film layers, with the layered coating improving the fast-charging capability of the battery cell. In particular, if the first and second anode film layers differ, this allows for the formation of different pore structures within the anode film layer, thereby reducing the tortuosity of lithium-ion transport and improving the fast-charging capability of the battery cell.

[0133] In some embodiments, both the first anode film layer and the second anode film layer comprise composite graphite particles.

[0134] The incorporation of composite graphite particles into the first anode film layer and the second anode film layer improves the fast charging capability of the battery cell.

[0135] In some embodiments, the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is greater than or equal to the volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer.

[0136] In the embodiment of the present application, the volume-averaged particle size Dv50 of a material refers to the particle size corresponding to 50% of the volume distribution. This can be tested using equipment and methods known in the art, for example by testing the Dv50 of particles using a Mastersizer 2000E laser particle size analyzer in accordance with test standard GB / T 19077-2016, wherein the active cathode material serves as the sample.

[0137] During fast charging of the battery cell, the overvoltage of the second anode film layer, which faces away from the current collector, is typically higher. The primary bottleneck in the anode film layer, which impairs the fast-charging capability of the battery cell, is located in the second anode film layer. The present application controls the particle size of the composite graphite particles in the second anode film layer so that it is relatively smaller, thereby shortening the lithium-ion transport path, improving the lithium-ion transport performance of the second anode film layer, and enhancing the fast-charging capability of the battery cell.

[0138] In some embodiments, the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is 8.5 µm to 14.8 µm, optionally 8.5 µm, 9.0 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, 14.8 µm or a value within a range formed by any two of these values.

[0139] In some embodiments, the volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer is 7.8 µm to 12.8 µm, optionally 7.8 µm, 8.0 µm, 8.5 µm, 9.0 µm, 9.5 µm, 10 µm, 10.5 µm, 11 µm, 11.5 µm, 12 µm, 12.5 µm, 12.8 µm or a value within a range formed by any two of these values.

[0140] Controlling the particle size of the graphite particles in the first and / or second anode film layers within a suitable range shortens the solid-state transport path for lithium ions, thereby improving fast-charging capability. Simultaneously, the material is not prone to agglomeration during the manufacturing process, thus enhancing its stability. Furthermore, coordinating the active anode material in the second and first anode film layers within the aforementioned range of volume-averaged particle size facilitates the formation of a porosity gradient between these two layers. This reduces the tortuosity of lithium-ion transport, further improving the fast-charging capability of the battery cell.

[0141] In some embodiments, the thickness fraction of the second anode film layer is 30% to 70%, optionally 30%, 40%, 50%, 60%, 70% or a value within a range formed by any two of these values, relative to the total thickness of the first anode film layer and the second anode film layer.

[0142] The thickness fraction of the second anode film layer is within the appropriate range, and the adjustment of the thickness fraction of the first anode film layer and the second anode film layer further increases the gradient difference in porosity between the upper and lower layers, reduces the tortuosity of lithium ion transport and improves the fast charging capability of the battery cell.

[0143] In some embodiments, the thickness of the first anode film layer at a battery cell charge level of 100% is 15 µm to 65 µm, for example 15 µm, 17 µm, 18 µm, 20 µm, 25 µm, 30 µm, 35 µm, 40 µm, 45 µm, 50 µm, 55 µm, 57 µm, 58 µm, 60 µm, 61 µm, 62 µm, 63 µm, 64 µm, 65 µm or a value within a range formed by any two of these values.

[0144] If the thickness of the first anode film layer is within the aforementioned range, it can increase the gradient difference in porosity between the first anode film layer and the second anode film layer, reduce the tortuosity of lithium ion transport, and improve the fast-charging capability of the battery cell.

[0145] In some embodiments, the thickness of the second anode film layer at a battery cell charge level of 100% is 15 µm to 65 µm, for example 15 µm, 17 µm, 18 µm, 20 µm, 25 µm, 30 µm, 35 µm, 40 µm, 45 µm, 50 µm, 55 µm, 57 µm, 58 µm, 60 µm, 61 µm, 62 µm, 63 µm, 64 µm, 65 µm or a value within a range formed by any two of these values. If the thickness of the second anode film layer is within the aforementioned range, it can regulate and increase the gradient difference in porosity between the first anode film layer and the second anode film layer, reduce the tortuosity of lithium ion transport, and improve the fast-charging capability of the battery cell.

[0146] In the embodiment of the present application, the test steps for the first anode film layer and the second anode film layer at a state of charge (SOC) of the battery cell are as follows: Charging the battery cell with a constant current of 0.33 C to 3.65 V, then further charging with a constant voltage of 3.65 V to 0.05 C, and termination of the charging process. At this point, the battery is at a state of charge of 100%. Disassembling the battery cell at a state of charge of 100% to remove the anode film. Examining the cross-section in the central region of the anode film in the thickness direction using a scanning electron microscope.Distinguishing the respective areas of the first anode film layer and the second anode film layer based on their interface, measuring the respective thickness of the two, for example, the thicknesses at ten positions of the first anode film layer are each measured, and their average value is calculated as the mean thickness of the first anode film layer, and the thicknesses at ten positions of the second anode film layer are each measured, and their average value is calculated as the mean thickness of the second anode film layer.

[0147] In some embodiments, the anode film layer optionally further comprises a conductive anode element. The present application does not impose any specific restrictions regarding the type of conductive anode element; for example, the conductive anode element may comprise at least one of superconducting carbon, conductive graphite, carbon black, carbon black, ketjen carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0148] In some embodiments, the mass fraction of the conductive medium of the anode is ≤5%, based on the total weight of the anode film layer.

[0149] In some embodiments, the anode film layer optionally includes an anode binder.

[0150] In some embodiments, the anode binder comprises one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin, polyvinyl alcohol, sodium alginate, and carboxymethyl chitosan.

[0151] In some embodiments, the mass fraction of the anode binder is ≤5%, based on the total weight of the anode film layer.

[0152] In some embodiments, the anode film layer optionally comprises other additives. For example, other additives may include thickeners, dispersants, etc., such as sodium carboxymethylcellulose (CMC-Na), PTC thermistor materials, etc.

[0153] In some embodiments, the mass fraction of the other additives is ≤ 2%, based on the total weight of the anode film layer.

[0154] In some embodiments, the anode collector can be a metal foil or a composite collector. Examples of metal foils include at least one foil made of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. The composite collector can comprise a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. For example, the metal material in the metal material layer can include at least one of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. For example, the polymer substrate can comprise at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0155] The anode film layer is typically formed by applying the anode slurry to the anode collector, followed by drying and cold pressing. The anode slurry is generally formed by dispersing the anode's active substance, an optional conductive agent, an optional binder, and other optional additives in a solvent and stirring uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP) or deionized water.

[0156] The anode foil does not preclude additional functional layers beyond the anode film layer. For example, in some embodiments, the anode foil of the present application further comprises an anode conductive layer that is clamped between the anode collector and the anode film layer and arranged on the surface of the anode collector. In other embodiments, the anode foil of the present application further comprises a protective layer that covers the surface of the anode film layer.

[0157] In some embodiments, the anode foil further comprises an anode conductive layer located between the anode collector and the anode film layer on at least one side, wherein the anode conductive layer comprises a conductive means, the conductive means comprising one or more from the group consisting of superconducting carbon, conductive graphite, acetylene carbon black, carbon black, ketjen carbon black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0158] By arranging an anode conductive layer, which includes a conductive medium, between the current collector and the anode film layer, the electrical conductivity of the anode foil is improved, thereby improving the fast charging capability of the battery cell.

[0159] In some embodiments, the thickness of the anode conductive layer is 0.5 µm to 2 µm, optionally 0.5 µm, 0.8 µm, 1 µm, 1.2 µm, 1.5 µm, 1.6 µm, 1.8 µm, 2 µm or a value within a range formed by any two of these values.

[0160] In the embodiment of the present application, the thickness of the anode conducting layer has a meaning known in this field. It can be measured using equipment and methods known in the prior art, with reference to the previously described test methods for the first anode film layer or the second anode film layer.

[0161] By controlling the thickness of the anode conductive layer within a suitable range, a balance can be achieved between the fast charging capability and the energy density of the battery cell.

[0162] In some embodiments, the anode conductive layer includes a binder for the anode conductive layer.

[0163] The binder in the anode conductive layer improves the adhesion between the anode collector and the anode film layer, thereby improving the structural stability of the anode foil.

[0164] In some embodiments, the binder for the anode conductive layer comprises one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin, polyvinyl alcohol, sodium alginate, and carboxymethyl chitosan.

[0165] In some embodiments, the density of the anode film layer at a battery cell charge level of 100% is 1.15 g / cm³. 3 up to 1.45 g / cm³ 3 For example, the density of the anode film layer at a battery cell charge level of 100% is 1.15 g / cm³. 3 , 1.18 g / cm³ 3 , 1.20 g / cm³ 3 , 1.22 g / cm³ 3 , 1.25 g / cm³ 3 , 1.28 g / cm³ 3 , 1.3 g / cm³ 3 , 1.32 g / cm³ 3 , 1.35 g / cm³3 , 1.36 g / cm³ 3 , 1.38 g / cm³ 3 , 1.4 g / cm³ 3 , 1.42 g / cm³ 3 , 1.45 g / cm³ 3 or a value within a range formed by any two of these values.

[0166] In an example relating to the embodiment of the present application, the density of the anode film layer at a state of charge (SOC) of the battery cell can be tested using the following procedure: Charge the battery cell with a constant current of 0.33 C to 3.65 V, then further charge it with a constant voltage of 3.65 V to 0.05 C, and terminate the charging process. At this point, the battery is at a state of charge of 100%. Disassemble the battery cell at a state of charge (SOC) of 100% to remove the anode foil, measure the density of the anode film layer, and take a single-sided coated anode foil (in the case of a double-sided coated electrode foil, the anode film layer of one side can be wiped off first), punch it out, and cut it into a small disc with an area of ​​S1, weigh it, and record it as M1, with the thickness being measured as H1.Then the anode film layer of the anode foil, which was weighed as described above, is wiped off, and the weight of one anode collector is weighed and recorded as M0, and the thickness H0 is measured. One-sided coating weight of the anode film layer = (weight of the anode foil M1 - weight of the anode collector M0) / S1, thickness of the anode film layer = thickness of the anode foil H1 - thickness of the anode collector H0, compression density of the anode film layer = one-sided coating weight of the anode film layer / thickness of the anode film layer.

[0167] Maintaining the pressure density of the anode film layer within a suitable range contributes to improved fast-charging capability of the battery cell.

[0168] In some embodiments, the one-sided coating weight of the anode film layer is 70 mg / 1540.25 mm². 2 up to 135mg / 1540.25 mm 2For example, the one-sided coating weight of the anode film layer is 70 mg / 1540.25 mm². 2 , 75 mg / 1540.25 mm z , 80 mg / 1540.25 mm 2 , 85 mg / 1540.25 mm 2 , 90 mg / 1540.25 mm 2 , 92 mg / 1540.25 mm 2 , 95 mg / 1540.25 mm 2 , 96 mg / 1540.25 mm 2 , 100 mg / 1540.25 mm 2 , 102 mg / 1540.25 mm 2 , 104 mg / 1540.25 mm 2 , 105 mg / 1540.25 mm 2 , 108 mg / 1540.25 mm 2 , 110 mg / 1540.25 mm 2 , 112 mg / 1540.25 mm 2 , 114 mg / 1540.25 mm 2 , 115 mg / 1540.25 mm 2 , 116 mg / 1540.25 mm 2 , 118 mg / 1540.25 mm 2 , 120 mg / 1540.25 mm 2 , 122 mg / 1540.25 mm 2 , 125 mg / 1540.25 mm 2 , 128 mg / 1540.25 mm 2 , 130 mg / 1540.25 mm 2 , 132 mg / 1540.25 mm 2 , 135 mg / 1540.25 mm 2 or a value within a range formed by any two of these values.

[0169] Maintaining the one-sided coating weight of the anode film layer within a suitable range contributes to improved fast-charging capability of the battery cell. [Cathode foil]

[0170] The cathode foil comprises a cathode collector and a cathode film layer arranged on at least one surface of the cathode collector and comprising an active cathode material. For example, the cathode collector has two surfaces that are opposite each other in its own thickness direction, with the cathode film layer arranged on one or both of the two opposite surfaces of the cathode collector.

[0171] In some embodiments, the mass fraction of lithium-containing phosphate with an olivine structure in the active cathode material can be greater than or equal to 80% and less than or equal to 100%. The active cathode material of the present application can thus be considered a lithium-containing phosphate system with an olivine structure. If the mass fraction of lithium-containing phosphate with an olivine structure is less than 100%, the active cathode material may additionally comprise conventional active cathode materials, such as, but not limited to, at least one lithium-containing transition metal oxide.Examples of lithium-containing transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and their respective modified compounds.

[0172] In some embodiments, the mass fraction of lithium-containing phosphate with an olivine structure in the active cathode material is 100%.

[0173] In some embodiments, the lithium-containing phosphate comprises an olivine structure: a lithium-containing phosphate matrix, and a coating layer located on at least part of the surface of the lithium-containing phosphate matrix, wherein the coating layer contains a carbon element.

[0174] The lithium-containing phosphate with an olivine structure comprises a loosely porous carbon coating layer, which increases the specific surface area of ​​the material. This facilitates effective contact between the electrolyte solution and the phosphate particles, promotes lithium ion transport at the phase interfaces, improves the electrical conductivity of the material, and increases the fast-charging capability of the battery cell.

[0175] In some embodiments, the lithium-containing phosphate matrix comprises a compound of the general formula Li x1 A y1 Me a1 M b1 P 1-c1 X c1 Y z1 , where 0.5≤x1≤1.3, 0≤y1≤1.3, 0.9≤x1+y1≤1.3, 0.9≤a1≤1.5, 0≤b1≤0.5, 0.9≤a1+b1≤1.5, 0≤c1≤0.5 and 3≤z1≤5 hold. where A includes at least one of Na, K and Mg; Me includes at least one of Mn, Fe, Co and Ni; M includes at least one 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; X includes at least one of S, Si, Cl, B, C, N, P; Y includes at least one of O, F.

[0176] In some embodiments, x1 is optionally 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 or a value within a range formed by any two of these values.

[0177] In some embodiments, y1 is optionally 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 or a value within a range formed by any two of these values.

[0178] In some embodiments, x1+y1 is optionally 0.9, 1.0, 1.1, 1.2, 1.3 or a value within a range formed by any two of these values.

[0179] In some embodiments, a1 is optionally 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 or a value within a range formed by any two of these values.

[0180] In some embodiments, b1 is optionally 0, 0.1, 0.2, 0.3, 0.4, 0.5 or a value within a range formed by any two of these values.

[0181] In some embodiments, a1+b1 is optionally 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 or a value within a range formed by any two of these values.

[0182] In some embodiments, c1 is optionally 0, 0.1, 0.2, 0.3, 0.4, 0.5 or a value within a range formed by any two of these values.

[0183] In some embodiments, z1 is optionally 3.0, 3.5, 4.0, 4.5, 5.0 or a value within a range formed by any two of these values.

[0184] The lithium-containing phosphate with an olivine structure exhibits favorable cycle stability, thereby improving the cycle performance of the battery cell.

[0185] In some embodiments, the lithium-containing phosphate matrix comprises one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium nickel phosphate, lithium cobalt phosphate and modified forms of one of the aforementioned substances, wherein the modified forms comprise one or more doping modifications and coating modifications.

[0186] During the charging and discharging cycles of the battery cell, lithium is released, stored, and consumed, resulting in varying molar lithium content at different discharge states. Active cathode materials such as LiFePO4, LiMnPO4, and LiFe 1-x Mn xPO4(0 < x < 1), LiNiPO4, LiCoPO4: the molar lithium content refers to the initial state of the material, namely the state before it is added. When the active cathode material is used in a battery system, the molar lithium content can change after charge-discharge cycles. Examples of active cathode materials include iFePO4, LiMnPO4, and LiFe. 1-x Mn x In PO4(0 < x < 1), LiNiPO4, LiCoPO4, etc., as described in the embodiments of the present application, the molar content of oxygen represents only a theoretical state value. The release of lattice oxygen can lead to fluctuations in the molar content of oxygen, which in turn leads to fluctuations in the actual molar content of oxygen. All such scenarios fall within the scope of protection of the present application.

[0187] In some embodiments, the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure is 0.8% to 2.3%, optionally 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.3%, or a value within a range formed by any two of these values.

[0188] The carbon content in materials is typically measured using infrared absorption techniques, such as infrared carbon-sulfur analyzers, or indirect carbon determination methods. The latter can refer to the relevant provisions on pages 3-4 of the national standard GB / T 3521-2008 (Methods for the chemical analysis of graphite).

[0189] Controlling the mass fraction of the carbon element in the coating layer within a suitable range not only improves the conductivity of the material and the fast-charging capability of the battery, but also balances the gram-specific capacity of the material, thus taking into account both the fast-charging capability and the energy density of the battery cell.

[0190] In some embodiments, the battery cell satisfies the following relationship: 0.08≤C / B≤1.15, where C represents the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure; where B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution.

[0191] In some embodiments, C / B is optionally 0.08, 0.10, 0.12, 0.15, 0.18, 0.2, 0.25, 0.30, 0.35, 0.40, 0.45, 0.5, 0.55, 0.60, 0.65, 0.70, 0.75, 0.8, 0.85, 0.90, 1.0, 1.05, 1.10, 1.15 or a value within a range formed by any two of these values.

[0192] As previously mentioned, the carbon element in the carbon coating layer improves the effective contact between the electrolyte solution and the phosphate particles, thereby enhancing the material's electrical conductivity. While the porous carbon coating improves wetting by the electrolyte solution, it also promotes side reactions between the phosphate particles and the electrolyte solution, leading to lithium ion consumption and impairing the battery cell's cycle performance. The first additive in the electrolyte solution supports the formation of a CEI film layer on the cathode side, thus reducing the likelihood of side reactions between the electrolyte solution and the active cathode material. This increases the stability of the cathode interface and improves the battery cell's cycle performance.

[0193] The present application achieves a synergistic effect between the two by controlling the mass fraction of the carbon element in the lithium-containing phosphate with an olivine structure and the mass fraction of the first additive within suitable ranges, which simultaneously improves the electrical conductivity of the material and increases the fast-charging capability of the battery cell, while at the same time taking into account the material cycle stability and the battery cycle performance.

[0194] In some embodiments, the coating layer further comprises a substance Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1 , where 0≤d1≤1, 0≤m1≤5 and 0≤n1≤4 hold; wherein M3 comprises one or more of the elements Ti, Zr, Hf, Ge or Sn, wherein M3 optionally has a valency of +4.

[0195] In some embodiments, the coating layer further comprises one or more of Li2FeTi(PO4)3, Li2FeZr(PO4)3, Li2FeSn(PO4)3.

[0196] In some embodiments, the carbon element and the material Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1 be arranged in different layers, with, for example, the carbon element forming an independent carbon coating layer and the substance Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1an independent fast-ion conducting layer. The carbon coating layer can be applied to the surface of phosphate particles, with the fast-ion conducting layer located on the surface of the carbon coating layer, i.e., the fast-ion conducting layer is located on a side of the carbon coating layer facing away from the phosphate particles. Alternatively, the fast-ion conducting layer can be applied to the surface of phosphate particles, with the carbon coating layer located on the surface of the fast-ion conducting layer, i.e., the carbon coating layer is located on a side of the fast-ion conducting layer facing away from the phosphate particles. Of course, the carbon element and the substance Li can be used. 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1 also be arranged in the same layer.

[0197] The coating layer includes Li 3-d1 Fe2-d1 M3 d1 (PO m1 ) n1 and exhibits excellent ionic conductivity. In combination with the carbon elements with outstanding electrical conductivity within the coating layer, this improves the overall electrical and ionic conductivity properties of the material. This enables improved fast-charging capability of the battery.

[0198] In the embodiment of the present application, the elemental concentrations in the active cathode material have a significance known in this field. Their determination can be carried out using generally known instruments and methods. For example, according to EPA 6010D-2014, the measurement can be performed using inductively coupled plasma optical emission spectrometry (ICP-OES, instrument type: Thermo iCAP 7400). After discharging the battery cell to a state of charge (SOC) of 0%, the cathode foil is removed. After cleaning with DMC After drying, the material undergoes high-temperature calcination to remove impurities. Subsequently, 0.4 g of the active cathode material is weighed, and 10 ml of aqua regia (concentration: 50%) is added. The mixture is then placed on a flat plate at 180°C for 30 minutes. After digestion on the flat plate, the volume is adjusted to 100 ml, and quantification is performed using the standard curve method.

[0199] In some embodiments, the powder density of the active cathode material at 30,000 N is 2.43 g / cm³. 3 up to 2.85 g / cm³ 3 , optional 2.43 g / cm² 3 , 2.44 g / cm³ 3 , 2.45 g / cm³ 3 , 2.46 g / cm³ 3 , 2.47 g / cm³ 3 , 2.48 g / cm³ 3 , 2.49 g / cm³ 3 , 2.5 g / cm³ 3 , 2.51 g / cm³ 3 , 2.55 g / cm³ 3 , 2.58 g / cm³ 3 , 2.60 g / cm³ 3 , 2.65 g / cm³ 3 , 2.68 g / cm³ 3, 2.70 g / cm³ 3 , 2.72 g / cm³ 3 , 2.75 g / cm³ 3 , 2.78 g / cm³ 3 , 2.80 g / cm³ 3 , 2.85 g / cm³ 3 or a value within a range formed by any two of these values.

[0200] If the powder density of the active cathode material is within the aforementioned range at 30,000 N, the energy density of the battery cell increases. Furthermore, since the active cathode material can be packed more densely within the cathode layer, the contact resistance between the particles is reduced, which further lowers the resistance of the electrode foil and improves the fast-charging capability of the battery cell.

[0201] In the embodiment of the present application, the powder density of the material has a meaning known in this field. It can be tested using methods and equipment generally known in this field. According to the testing standard GB / T 24533-2009, for example, the procedure is carried out as follows: a specific quantity of the active cathode material is taken as a sample and placed in the die of an electronic compression testing machine (type: UTM7305) with a base area of ​​1.327 cm². 2 A pressure of 3000 kg (corresponding to 30000 N) is applied, held for 30 seconds, and then released. After a holding time of 10 seconds, the value is recorded, and the powder density of the active cathode material under a force of 30000 N is calculated.

[0202] In some embodiments, the density of the cathode film layer at a battery cell charge level of 100% is 2.50 g / cm³. 3 up to 2.80 g / cm³3 , optional 2.50 g / cm² 3 , 2.55 g / cm³ 3 , 2.60 g / cm³ 3 , 2.65 g / cm³ 3 , 2.70 g / cm³ 3 , 2.75 g / cm³ 3 , 2.80 g / cm³ 3 or a value within a range formed by any two of these values.

[0203] In the embodiment of the present application, the density of the cathode film layer at a state of charge of the battery cell of 100% has a meaning known in this field and can be tested using equipment and methods known in this field, the test method being analogous to the method described for the density of the anode film layer.

[0204] Within this suitable range of cathode film layer density, the battery cell exhibits a high energy density.

[0205] In some embodiments, the cathode film layer optionally further comprises a conductive cathode element. The present application does not impose any specific restrictions regarding the type of conductive cathode element; for example, the conductive cathode element comprises at least one of superconducting carbon, conductive graphite, carbon black, carbon black, ketamine black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass fraction of the conductive cathode element is ≤5%, based on the mass of the cathode film layer.

[0206] In some embodiments, the cathode film layer optionally comprises a cathode binder. The present application does not impose any specific restrictions regarding the type of cathode binder; for example, the cathode binder may comprise at least one of polyvinylidene fluoride, polytetrafluoroethylene, a terpolymer of vinylidene fluoride-tetrafluoroethylene-propylene, a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, and fluorinated acrylic ester resins. In some embodiments, the mass fraction of the cathode binder is ≤5%, based on the mass of the cathode film layer.

[0207] In some embodiments, the cathode collector can be a metal foil or a composite collector. Examples of metal foils include at least one foil made of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. The composite collector can comprise a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. For example, the metal material in the metal material layer can include at least one of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. The polymer substrate can, for example, include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0208] The cathode film layer is typically formed by applying the cathode slurry to the cathode collector, followed by drying and cold pressing. The cathode slurry is generally formed by dispersing the active cathode material, an optional conductive agent, an optional binder, and other components in a solvent and stirring uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP). The cathode film does not preclude additional functional layers beyond the cathode film layer. For example, in some embodiments, the cathode film of the embodiment of the present application further comprises a cathode conductive layer that is clamped between the cathode collector and the cathode film layer and arranged on the surface of the cathode collector.In other embodiments, the cathode film of the embodiment of the present application further comprises a protective layer covering the surface of the cathode film layer. [Electrolyte solution]

[0209] During the charging and discharging process of the battery cell, active ions, such as lithium ions, migrate back and forth between the cathode foil and the anode foil, being stored and removed in the process. The electrolyte solution serves to conduct these active ions between the cathode foil and the anode foil.

[0210] In one embodiment of the present application, the electrolyte solution comprises a first additive, wherein the first additive comprises at least one of ethylene carbonate and ethylene carbonate derivatives, and wherein, based on the total mass of the electrolyte solution, the mass fraction of the first additive is 1% to 12%. wherein the ethylene carbonate derivative comprises a compound represented by formula I: wherein R1, R2, R3 and R4 each independently comprise one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-CS halogenated alkyl, wherein R1, R2, R3 and R4 are not simultaneously hydrogen atoms.

[0211] A first additive, comprising ethylene carbonate and / or an ethylene carbonate derivative, is added to the electrolyte solution. The ethylene carbonate and the ethylene carbonate derivative preferentially participate in the formation of the SEI film on the anode side compared to other components in the electrolyte solution. The organic substances are present in a higher concentration in the film formed by the ethylene carbonate and the ethylene carbonate derivative, which improves the overall flexibility of the SEI film. This enhances the stability of the SEI film and the anode interface during the cycle, reduces reactions between the active anode material and the electrolyte solution, decreases lithium ion consumption, and improves the cycle and storage performance of the battery cell.Furthermore, controlling the mass fraction of the first additive within a suitable range not only improves the flexibility and stability of the SEI film, but also regulates its thickness within a suitable range. This simultaneously achieves stability at the anode interface and low impedance, thus benefiting both the cycle performance and fast-charging capability of the battery cell.

[0212] In some embodiments, at least one of R1, R2, R3 and R4 comprises a fluorine atom.

[0213] The carbonate ester derivative, in which at least one of R1, R2, R3, and R4 is a fluorine atom, readily undergoes ring opening to form an SEI film on the anode surface containing a higher proportion of organic substances. This facilitates improved overall flexibility of the SEI film, thereby enhancing the stability of the SEI film and the anode interface during the cycle and increasing the cycle performance of the battery cell.

[0214] In some embodiments, the ethylene carbonate derivative comprises one or more of the group consisting of fluorinated ethylene carbonate, difluoroethylene carbonate and trifluoromethylethylene carbonate.

[0215] Suitable ethylene carbonate derivative additives can form an SEI film on the anode side. This film contains a high proportion of organic substances, which improves the overall flexibility of the SEI film. This, in turn, enhances the stability of the SEI film and the anode interface during the cycle, thus increasing the cycle performance of the battery cell. Simultaneously, the SEI film, formed with the involvement of fluorinated ethylene carbonate, difluoroethylene carbonate, and trifluoromethylethylene carbonate, exhibits low impedance, which also contributes to improving the fast-charging capability of the battery cell.

[0216] In some embodiments, the electrolyte solution further comprises an organic solvent, wherein the organic solvent comprises one or more of a first organic solvent and a second organic solvent. wherein the first organic solvent comprises at least one of a cyclic carbonate and a chain-like carbonate, optionally being a cyclic carbonate; wherein the second organic solvent comprises R5-COO-R6, wherein R5 comprises one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-CS halogenated alkyl, wherein R6 comprises one from the group consisting of a C1-C5 alkyl and a C1-C5 halogenated alkyl.

[0217] The first organic solvent, which is a cyclic or chain-like carbonate, possesses a relatively high dielectric constant and excellent ionic conductivity, which is beneficial for improving the electrical conductivity of the electrolyte solution. The second organic solvent has a low viscosity, which is also beneficial for improving the electrical conductivity of the electrolyte solution. The electrolyte solution contains the first organic solvent and / or the second organic solvent, which contributes to improved lithium ion migration and enhances the fast-charging capability of the battery cell.

[0218] In some embodiments, the cyclic carbonate comprises one or more from the group consisting of ethylene carbonate, propylene carbonate and butylene carbonate.

[0219] In some embodiments, the chain-like carbonate comprises one or more from the group consisting of dimethyl carbonate, diethyl carbonate and methylethyl carbonate.

[0220] In some embodiments, the second organic solvent comprises one or more from the group consisting of methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate and ethyl butyrate.

[0221] In some embodiments, the mass fraction of the first organic solvent, based on the total mass of the electrolyte solution, is 20% to 72%, optionally 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 72% or a value within a range formed by any two of these values.

[0222] A first organic solvent containing suitable amounts of cyclic carbonates and chain-like carbonates can further improve the electrical conductivity of the electrolyte solution, thereby facilitating lithium ion migration and improving the fast-charging capability of the battery cell.

[0223] The type and mass of the solvent in the electrolyte solution can be determined by electrolyte analysis using methods known to those skilled in the art. For example, the composition of the electrolyte solution can be determined by liquid chromatography, ultraviolet spectrophotometry, or ultraviolet visible spectrophotometry. For instance, a battery cell is disassembled to obtain a free electrolyte solution. The aforementioned free electrolyte solution obtained from the battery cell is diluted 3- to 10-fold with acetonitrile to obtain the electrolyte dilution solution for testing. A complete qualitative analysis of the electrolyte dilution solution is performed in the instrument using the GC-MS 3100 gas chromatograph for organic components, with the injector temperature set at 250°C and the scan range at 35 µm to 270 µm.After completion of the test, the total ion chromatogram is obtained for each organic substance. Based on the peak positions of the chromatogram, the types of the corresponding organic substances are compared, and the percentage content of each organic substance is calculated based on the peak area.

[0224] In some embodiments, the electrolyte solution further comprises a second additive, wherein the second additive comprises one or more from the group consisting of a sulfur-containing additive and a lithium salt additive.

[0225] Additives are components that are present in relatively small amounts in the electrolyte solution, typically comprising no more than 10% by mass. They are characterized by their high specificity and low required dosage, and can significantly optimize certain aspects of battery performance without altering the production processes.

[0226] The sulfur-containing additive and the lithium salt additive are able to improve the interfacial film properties on the cathode side and / or anode side, improve the interfacial chemistry between the cathode and / or anode and the electrolyte solution, and improve the fast charging capability and cycle performance of the battery.

[0227] In some embodiments, the sulfur-containing additive comprises one or more from the group consisting of sulfate vinyl ester, bisulfate vinyl ester, sulfite butene ester, 1,3-propanesulfonic acid lactone, ethylene sulfite and methylenedisulfonic acid methyl ester.

[0228] In some embodiments, the lithium salt additive comprises one or more from the group consisting of lithium difluorophosphate, lithium difluorooxalate borate, lithium tetrafluoroborate and lithium dioxalate borate.

[0229] In some embodiments, the electrolyte solution further comprises a lithium salt, wherein the lithium salt comprises one or two from the group consisting of fluorinated sulfonylimide salt and lithium hexafluorophosphate.

[0230] The fluorinated sulfonylimide salt and the lithium hexafluorophosphate readily dissociate, facilitating rapid lithium ion migration and improving the fast-charging capability of the battery cell. Furthermore, the fluorinated sulfonylimide salt and the lithium hexafluorophosphate exhibit relative stability within the electrolyte system, thereby improving the cycle performance of the battery cell.

[0231] In some embodiments, the fluorinated sulfonylimide salt comprises one or two from the group consisting of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)amide.

[0232] In some embodiments, the lithium salt comprises lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate, wherein the molar concentration ratio of lithium bis(fluorosulfonyl)imide to lithium hexafluorophosphate is 0.2 to 1.0, optionally 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or a value within a range formed by any two of these values.

[0233] In some embodiments, the molar concentration of lithium bis(fluorosulfonyl)imide is 0.2 mol / L to 0.5 mol / L, optionally 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.40 mol / L, 0.45 mol / L, 0.5 mol / L or a value within a range formed by any two of these values.

[0234] The molar concentration of lithium hexafluorophosphate is 0.5 mol / L to 1.2 mol / L, optionally 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.2 mol / L or a value within a range formed by any two of these values. [Separator film]

[0235] The electrode assembly includes a separating film that is positioned between the cathode and the anode.

[0236] The present application does not impose any specific restrictions regarding the type of separating film, and any known separating film with a porous structure and good chemical and mechanical stability can be selected.

[0237] For example, the separator film material can be at least one of the following: glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator film can be a single-layer film or a multi-layer composite film without any particular restriction. If the separator film is a multi-layer composite film, the materials of the layers can be the same or different without any particular restriction. The separator element can be a separate component positioned between the cathode and the anode, or it can adhere to the surfaces of the cathode and the anode. A coating of inorganic particles, a coating of organic particles, or a coating of an organic-inorganic composite material can also be applied to the surface of the separator film.

[0238] In some embodiments, the thickness of the separating film is 4 µm to 12 µm, optionally 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm or a value within a range formed by any two of these values.

[0239] In the embodiment of the present application, the thickness of the separating film has a meaning known in this field. It can be tested using methods and equipment generally known in this field. For example, a newly manufactured separating film can be taken as a sample, or a fully discharged battery cell (discharged to the lower cutoff voltage, resulting in a state of charge (SOC) of approximately 0%) can be reverse disassembled. The separating film is obtained from the battery cell, dried, and used as a sample. The separating film is then cut with an ion beam cutter to produce a cross-section, and the thickness of the separating film is subsequently measured with a scanning electron microscope.

[0240] Within the appropriate thickness range, lithium ions migrate through shorter separation paths via the separating film, thereby reducing the internal resistance of the battery cell and improving the fast charging capability of the battery cell.

[0241] In some embodiments, the porosity of the separating film is 20% to 70%, optionally 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or a value within a range formed by any two of these values.

[0242] In the embodiment of the present application, porosity refers to the percentage of the pore volume relative to the total volume of the separating film. The porosity can be tested in accordance with standard GB / T 36363-2018, "Polyolefin separating film for battery cells." It should be noted that the actual test procedure may differ slightly from the standard procedure to account for variations in test equipment and measurement errors, and to minimize any potential impact on the porosity measurements, thereby obtaining more accurate test results.

[0243] Within the appropriate porosity range, the migration rate of lithium ions through the separating film increases, thereby further reducing the internal resistance of the battery cell and improving the fast charging capability of the battery cell.

[0244] In some embodiments, the battery cell is configured to have a charging time of 5 to 10.5 minutes from a state of charge of 10% to a state of charge of 80%, optionally 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 10.5 minutes or a value within a range formed by any two of these values.

[0245] In some embodiments, the charging process from a state of charge of 10% to a state of charge of 80% comprises several charging steps, wherein the maximum state of charge of any given charging step differs from the maximum state of charge of the immediately adjacent charging step by no more than 5% of the state of charge.

[0246] for example, by 1% of the state of charge, 1.5% of the state of charge, 2% of the state of charge, 2.5% of the state of charge, 3% of the state of charge, 3.5% of the state of charge, 4% of the state of charge, 4.5% of the state of charge, 5% of the state of charge, or a value within a range formed by any two of these values.

[0247] The charging process of the battery cell from a state of charge of 10% to 40% comprises several charging steps. For each charging step, charging can be carried out at any rate between 5C and 10C. The charging rate corresponding to each step can be 5C, 5.5C, 6C, 6.5C, 7C, 7.5C, 8C, 8.5C, 9C, 9.5C, 10C, or a value within a range formed by any two of these values.

[0248] The charging process of the battery cell from a state of charge of 40% to 80% also comprises several charging steps. The charging rate for each individual charging step is lower than the charging rate for each charging step in the process from a state of charge of 10% to 40%. Furthermore, the charging rate for the step at which a state of charge of 80% is reached is set to a value between 2.5C and 7C.

[0249] For example, the charging steps for a battery cell from a charge level of 10% to 80% can be carried out as follows: Charging from 10% SOC to 15% SOC with a constant current of 7.0 C; Charging from 15% SOC to 20% SOC with a constant current of 7.0 C; Charging from 20% SOC to 25% SOC with a constant current of 7.0 C; Charging from 25% SOC to 30% SOC with a constant current of 7.0 C; Charging from 30% SOC to 35% SOC with a constant current of 6.2 C; Charging from 35% SOC to 40% SOC with a constant current of 5.7 C; Charging from 40% SOC to 45% SOC with a constant current of 5.2 C; Charging from 45% SOC to 50% SOC with a constant current of 4.8 C; Charging from 50% SOC to 55% SOC with a constant current of 4.6 C; Charging from 55% SOC to 60% SOC with a constant current of 4.4 C; Charging from 60% SOC to 65% SOC with a constant current of 4.2 C; Charging from 65% SOC to 70% SOC with a constant current of 3.9 C; Charging from 70% SOC to 75% SOC with a constant current of 3.5 C; Charging from 75% SOC to 80% SOC with a constant current of 3.0 C.

[0250] The battery cell has a high charging speed and excellent fast-charging capability.

[0251] In some embodiments, the volumetric energy density of the battery cell is 395 Wh / L to 530 Wh / L, optionally 395 Wh / L, 400 Wh / L, 410 Wh / L, 420 Wh / L, 430 Wh / L, 440 Wh / L, 450 Wh / L, 460 Wh / L, 470 Wh / L, 480 Wh / L, 490 Wh / L, 500 Wh / L, 510 Wh / L, 520 Wh / L, 530 Wh / L or a value within a range formed by any two of these values.

[0252] The battery cell has a relatively high volumetric energy density.

[0253] In the embodiment of the present application, the volumetric energy density of the battery cell has a meaning known in this field. It can be tested using equipment and methods generally known in this field. For example, it is illustrated by an example with an upper charge limit of the battery of 3.65 V and a battery discharge cutoff voltage of 2.0 V. The battery cell is placed at 25°C and charged to 3.65 V with a constant current of 0.33 C, followed by a constant voltage charge to 0.05 C. It is then discharged to 2.0 V with a constant current of 0.33 C, and the discharge capacity A0 at this time is recorded. Unit: Ah. The length, width, and height of the battery cell are measured using calipers (usually calculated based on the dimensions of the battery casing, excluding the height of the electrode terminals and the insulating film outside the casing).Calculating the battery cell volume V0, unit: L. The volumetric energy density VED of the battery cell is VED = (A0 × discharge plateau voltage) / Vo, unit: Wh / L. [Battery device]

[0254] In some examples, the cathode foil, the anode foil and the diaphragm can be assembled into an electrode component by a winding process or a stacking process.

[0255] In some embodiments, the battery cell may include an outer casing. The outer casing can be used to encapsulate the electrode component and electrolyte described above.

[0256] In some embodiments, the outer packaging of the battery cell can be a rigid casing, such as a hard plastic casing, an aluminum casing, a steel casing, etc. The outer packaging of the battery cell can also be a flexible casing, such as a bag-like soft casing. The flexible casing can be made of plastic, and examples of such plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0257] The present application does not subject the shape of the battery cell to any particular restrictions, so that it can be cylindrical, square or in any other shape. For example, shows Fig. 1 a square structured battery cell 5 as an example.

[0258] In some embodiments, such as in Fig.As shown in Figure 2, the outer packaging can comprise a housing 51 and a cover plate 53. The housing 51 can include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening that communicates with the receiving cavity, and the cover plate 53 can cover the opening to close the receiving cavity. The cathode foil, the anode foil, and the diaphragm can be assembled into an electrode component 52 by a winding or stacking process. The electrode component 52 is encapsulated in the receiving cavity. The electrolyte solution permeates the electrode component 52. The number of electrode components 52 contained in the battery cell 5 can be one or more, selected by those skilled in the art according to the specific practical requirements.

[0259] In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be 1 or more than 1, the exact number being selected by experts in this field depending on the application and capacity of the battery module.

[0260] Fig. Figure 3 shows a battery module 4 as an example. With reference to Fig. 3. The multiple battery cells 5 in the battery module 4 can be arranged sequentially along a longitudinal direction of the battery module 4. Of course, they can also be arranged in any other desired way. Furthermore, the multiple battery cells 5 can be fastened by means of fastening elements.

[0261] Optionally, the battery module 4 can also include a casing with a receiving space in which several battery cells 5 are housed.

[0262] In some embodiments, the battery cells can be assembled into a battery pack, and the number of battery cells contained in the battery pack can be 1 or more than 1, with the exact number being selected by experts in this field depending on the application and capacity of the battery module.

[0263] Fig. 4 and Fig. Figure 5 shows a battery pack 1 as an example. As in Fig. 4 and Fig. As shown in Figure 5, the battery pack 1 can comprise a battery housing and a plurality of battery modules 4 arranged within the battery housing. The battery housing comprises an upper housing 2 and a lower housing 3, wherein the upper housing 2 can cover the lower housing 3 and form an enclosed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged within the battery housing in any desired configuration.

[0264] Furthermore, the present application provides a power-consuming device comprising at least one battery cell, battery module, or battery pack provided by the present application. The battery cell, battery module, or battery pack can be used as a power source for the power-consuming device or as an energy storage unit for the power-consuming device. The power-consuming device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0265] Depending on requirements, the power-consuming device can be a battery cell, a battery module or a battery pack.

[0266] Fig. Figure 6 shows an example of a power-consuming device. This device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the battery cell in this power-consuming device, a battery pack or battery module can be used.

[0267] Another example of such a device is a mobile phone, a tablet, a laptop, etc. The device usually needs to be light and thin and can use a battery cell as a power source. I. Manufacturing processes of the exemplary embodiments

[0268] The following exemplary embodiments describe in more detail the subject matter disclosed in the embodiments of the present application. These exemplary embodiments serve only for illustration, since various modifications and variations within the disclosed embodiments of the present application are obvious to the person skilled in the art. Unless otherwise stated, all parts, percentages, and ratios given in the following exemplary embodiments are based on mass. All reagents used in the exemplary embodiments are commercially available or are synthesized by routine procedures and are ready for use without further processing. All instruments used in the exemplary embodiments are commercially available. Exemplary embodiment 1(1) Production of the cathode foil

[0269] The cathode foil comprises a cathode collector, a cathode conductive layer, and a cathode film layer on the cathode collector. The cathode collector is an aluminum foil with a thickness of 13 µm.

[0270] The cathode conductive layer on the cathode collector is a film formed by uniformly mixing the conductive material of the cathode (superconducting carbon), the cathode binder (polyvinylidene fluoride (PVDF)), and the solvent (N-methylpyrrolidone (NMP)), applying it to the current collector surface, and drying. It has a thickness of 1 µm. The mass fraction of the conductive material of the cathode in the cathode conductive layer is 40%, while that of the cathode binder is 60%.

[0271] The cathode film layer consists of a film formed by applying a cathode slurry (solvent: N-methylpyrrolidone, NMP) evenly to the surface of the cathode conductive layer, then drying and cold pressing. This cathode film layer consists of active cathode material 1, the binder polyvinylidene fluoride (PVDF), and the conductive agent acetylene carbon black in a weight ratio of 97:2:1.

[0272] The active cathode material comprises lithium iron phosphate having a coating layer, wherein the coating layer envelops the surface of lithium iron phosphate particles, the coating layer comprising lithium iron titanium phosphate Li2FeTi(PO4)3 and carbon element, wherein the mass fraction of the carbon element is 1.12%.

[0273] The one-sided coating weight of the cathode film layer is 250mg / 1540.25 mm². 2 . (2) Production of the anode foil

[0274] The anode foil comprises an anode collector, an anode conductive layer, and an anode film layer on the anode collector. The anode collector is a copper foil with a thickness of 5 µm.

[0275] The anode conductive layer on the anode collector is a film formed by uniformly mixing the anode conductive material (superconducting carbon), the anode binder (styrene-butadiene rubber, SBR), the thickener (sodium carboxymethylcellulose, CMC-Na), and the solvent (water), applying it to the surface of the anode collector, and allowing it to dry. The resulting film has a thickness of 1 µm. The mass fraction of the anode conductive material in the anode conductive layer is 35%, that of the anode binder is 60%, and that of the thickener is 5%.

[0276] The anode film layer comprises a film layer formed by applying an anode slurry (using deionized water as a solvent) evenly to the surface of the anode conductive layer, followed by drying and cold pressing.

[0277] The one-sided coating weight of the anode film layer is 95 mg / 1540.25 mm². 2 .

[0278] The anode film layer comprises a first anode film layer and a second anode film layer, with the first anode film layer being located on the surface of the anode conducting layer and the second anode film layer being located on the surface of the first anode film layer.

[0279] The first anode film layer comprises composite graphite particles, silicon-carbon composite material, the conductive agent acetylene carbon black, the binder styrene-butadiene rubber, and the thickening agent sodium carboxymethylcellulose in a mass ratio of 91.5:5:0.5:2:1. The Dv50 value of the composite graphite particles is 11.3 µm.

[0280] The second anode film layer comprises composite graphite particles, silicon-carbon composite material, the conductive agent acetylene carbon black, the binder styrene-butadiene rubber, and the thickening agent sodium carboxymethylcellulose in a mass ratio of 92.5:5:0.5:1:1. The Dv50 value of the composite graphite particles is 11.3 µm.

[0281] The thickness ratio between the first film layer and the second film layer is 50%:50%. (3) Release film

[0282] The separating film comprises a base film which is a polyethylene layer with a thickness of 7 µm and a porosity of 42%. (4) Preparation of the electrolyte solution

[0283] The electrolyte solution comprises an organic solvent, lithium salt, a first additive, and a second additive.

[0284] The organic solvent comprises 39.0 wt% of a chain-like carboxylate ester solvent (ethyl acetate) and 39.0 wt% of a carbonate ester solvent (27.3 wt% ethylene carbonate (EC), 11.7 wt% dimethyl carbonate). The mass fraction of each component in the organic solvent is calculated based on the mass of the electrolyte solution.

[0285] Based on the mass of the electrolyte solution, the total mass fraction of the first and second additives is 7% and comprises vinyl carbonate VC, fluorinated ethylene carbonate FEC, ethylene sulfite ES and lithium difluorooxaloborate LiDFOB in a mass ratio of 5:1:0.5:0.5.

[0286] The lithium salt comprises lithium difluorosulfonylimide (LiFSI) with a mass fraction of 4.5% and lithium hexafluorophosphate (LiPF6) with a mass fraction of 10.5%, the mass fraction of the lithium salt being calculated based on the mass of the electrolyte solution. (5) Production of the battery cell

[0287] The aforementioned cathode foil, separator film, and anode foil are stacked sequentially, with the separator film positioned between the cathode and anode foils to act as an insulator, thus forming an electrode assembly. This electrode assembly is inserted into the outer packaging, dried, and then filled with electrolyte. After vacuum sealing, curing, forming, and shaping, a battery cell is obtained. Examples 2 to 5

[0288] In embodiments 2-5, the one-sided coating weight of the cathode film layer and the mass fraction of the silicon-carbon composite material in the first and second anode film layers are adjusted compared to embodiments 1. The specific parameters are listed in Table 1. Examples 6 to 9

[0289] In contrast to embodiment 1, embodiments 6-9 adjust the mass fraction of ethylene carbonate, dimethyl carbonate, ethyl acetate, and the first additive in the electrolyte solution, as well as the mass fraction of the silicon-carbon composite material in the first and second anode film layers. The specific parameters are listed in Table 1. Examples 10 to 12

[0290] In embodiments 10-12, the mass fraction of carbon in the lithium iron phosphate coating layer is adjusted compared to embodiment 1. The specific parameters are listed in Table 1. Example 13

[0291] In contrast to embodiment 1, embodiment 13 adjusts the one-sided coating weight of the cathode film layer and the anode film layer, as well as the mass fraction of ethylene carbonate, dimethyl carbonate, ethyl acetate, and the first additive in the electrolyte solution. The specific parameters are listed in Table 1. Comparative example 1

[0292] In comparison to embodiment 1, the one-sided coating weight of the cathode film layer and the anode film layer is adjusted in comparative example 1, and the anode film layer does not include a silicon-carbon composite material. The specific parameters are listed in Table 1. Comparative example 2

[0293] In comparison to embodiment 1, the single-sided coating weight of the cathode film layer and the mass fraction of the silicon-carbon composite material in the first and second anode film layers are adjusted in comparative example 2. The specific parameters are listed in Table 1. Comparative examples 3 to 4

[0294] In comparison to embodiment 1, the mass fraction of ethylene carbonate, dimethyl carbonate, ethyl acetate, and the first additive in the electrolyte solution is adjusted in comparative examples 3-4. The specific parameters are listed in Table 1. II. Performance test.

[0295] 1. Charging time for the battery cell from 10% SOC to 80% SOC using the following charging steps: Using the battery cell from embodiment 1 as an example:

[0296] Charging begins at 30°C from a battery cell state of 10% SOC. Charging from 10% SOC to 15% SOC with a constant current of 7.0 C; Charging from 15% SOC to 20% SOC with a constant current of 7.0 C; Charging from 20% SOC to 25% SOC with a constant current of 7.0 C; Charging from 25% SOC to 30% SOC with a constant current of 7.0 C; Charging from 30% SOC to 35% SOC with a constant current of 6.2 C; Charging from 35% SOC to 40% SOC with a constant current of 5.7 C; Charging from 40% SOC to 45% SOC with a constant current of 5.2 C; Charging from 45% SOC to 50% SOC with a constant current of 4.8 C; Charging from 50% SOC to 55% SOC with a constant current of 4.6 C; Charging from 55% SOC to 60% SOC with a constant current of 4.4 C; Charging from 60% SOC to 65% SOC with a constant current of 4.2 C; Charging from 65% SOC to 70% SOC with a constant current of 3.9 C; Charging from 70% SOC to 75% SOC with a constant current of 3.5 C; Charging from 75% SOC to 80% SOC with a constant current of 3.0 C. Recording the total charging time.

[0297] Minor variations in charging time between 10% and 80% SOC for battery cells in different embodiments and comparison examples can be achieved by slight adjustments to the charging rates mentioned above. Overall, the charging rate decreases progressively from low to high SOC. The specific charging rate for each SOC interval is determined using the following test method: Charging the battery cell at 25°C with a constant current of 1 / 3 C until the charging cutoff voltage of 3.65 V, then charging with a constant current to 0.05 C, resting for 5 minutes, and discharging with a constant current of 1 / 3 C until the discharge cutoff voltage of 2 V. Recording the actual capacity in C.The battery cell is then charged sequentially at 0.5C, 1.0C, 1.5C, 2.0C, 2.5C, 3.0C, 3.5C, 4.0C, 4.5C, 5.0C, 5.5C, 6.0C, 6.5C, 7.0C, 7.5C, 8.0C, 8.5C, 9.0C, 9.5C, 10.0C, until the complete cell charge cutoff voltage of 3.65 V or the lithium deposition potential of 0 mV is reached (whichever comes first). After each charge cycle, a discharge at 1C must be performed until the complete cell discharge cutoff voltage of 2 V is reached. Record the corresponding anode potential when a state of charge (SOC) of 10%, 15%, 20%, 25%, 30% ... 80% is reached at different charging rates. Plot the curve of rate-anode potentials for different SOC states. After linear fitting, determine the appropriate charging rate for a lithium deposition potential of 0 mV at different states of charge.This charging rate is used for the corresponding state-of-charge interval during the aforementioned charge duration test, with a charging rate of 7C from 10% SOC to 15% SOC representing the maximum charging rate tolerated by the mechanical components of the battery cell. The specific charging rates are listed in Tables 1 and 2. Table 1 Charge rate / C from 10%SOC to 15%SOC Charge rate / C from 15%SOC to 20%SOC Charge rate / C from 20%SOC to 25%SOC Charge rate / C from 25%SOC to 30%SOC Charge rate / C from 30%SOC to 35%SOC Charge rate / C from 35%SOC to 40%SOC Charge rate / C from 40%SOC to 45%SOC Charge rate / C from 45%SOC to 50%SOC Example 1 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Example 2 7,0 7,0 7,0 7,0 6,8 6,2 5,7 5,2 Example 3 7,0 7,0 7,0 7,0 6,5 6,0 5,4 5,0 Example 4 7,0 7,0 6,5 6,2 5,9 5,4 4,9 4,5 Example 5 7.0 6,5 6,2 5,8 5,3 4,9 4,5 4,1 Example 6 7,0 7,0 7,0 7,0 6,6 6,1 5,5 5,1 Example 7 7,0 7,0 7,0 6,5 6,0 5,6 5,1 4,7 Example 8 7,0 7,0 7,0 6,5 6,0 5,5 5,0 4,6 Example 9 7,0 6,7 6,4 6,0 5,5 5,1 4,6 4,3 Example 10 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Example 11 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Example 12 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Example 13 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Comparative example 1 7,0 7,0 7,0 7,0 6,2 5,7 5,2 4,8 Comparative example 2 6,0 6,0 5,7 5,4 5,1 4,7 4,3 3,9 Comparative example 3 7,0 7,0 7,0 7,0 6,8 6,2 5,7 5,2 Comparative example 4 7,0 6,7 6,4 5,9 5,4 4,9 4,5 4,2 Table 2 Charge rate / C from 45% SOC to 50% SOC Charge rate / C from 50% SOC to 55% SOC Charge rate / C from 55% SOC to 60% SOC Charging rate / C from 60% SOC to 65% SOC Charge rate / C from 65% SOC to 70% SOC Charge rate / C from 70% SOC to 75% SOC Charge rate / C from 75% SOC to 80% SOC Example 1 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Example 2 5,2 5,0 4,8 4,6 4,3 3,8 3,3 Example 3 5,0 4,8 4,6 4,4 4,1 3,7 3,1 Example 4 4,5 4,3 4,2 4,0 3,7 3,3 2,8 Example 5 4,1 4,0 3,8 3,6 3,4 3,0 2,6 Example 6 5,1 4,9 4,7 4,5 4,1 3,7 3,2 Example 7 4,7 4,5 4,3 4,1 3,8 3,4 2,9 Example 8 4,6 4,4 4,2 4,0 3,8 3,4 2,9 Example 9 4,3 4,1 3,9 3,7 3,5 3,1 2,7 Example 10 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Example 11 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Example 12 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Example 13 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Comparative example 1 4,8 4,6 4,4 4,2 3,9 3,5 3,0 Comparative example 2 3,9 3,8 3,6 3,5 3,2 2,9 2,5 Comparative example 3 5,2 5,0 4,8 4,6 4,3 3,8 3,3 Comparative example 4 4,2 4,0 3,8 3,6 3,4 3,0 2,6 2. Capacity retention rate after 1000 cycles of the battery cell at 30 °C

[0298] Charge the battery cell at 30°C from 0% SOC using the charging rates specified below, corresponding to the different SOC values, until 100% SOC is reached. Continue charging at a constant current of 0.33C until 3.65V is reached. Allow to rest for 30 minutes and discharge at a constant current of 1C until 2.0V is reached. This constitutes one charge-discharge cycle. Record the capacity Co after the first cycle. Repeat the above charge-discharge cycle steps until 1000 cycles are completed. Record the capacity Cn after the 1000th cycle. The capacity retention rate after 1000 cycles at 30°C is calculated as follows: Capacity retention rate = Cn / C0 × 100%. A higher capacity retention rate indicates superior cycle performance of the battery cell. The charging process from 0% SOC to 100% SOC proceeds as follows:

[0299] Using the battery cell from embodiment 1 as an example: Charging from 0% SOC to 10% SOC with a constant current of 1 C; Charging from 10% SOC to 15% SOC with a constant current of 7.0 C; Charging from 15% SOC to 20% SOC with a constant current of 7.0 C; Charging from 20% SOC to 25% SOC with a constant current of 7.0 C; Charging from 25% SOC to 30% SOC with a constant current of 7.0 C; Charging from 30% SOC to 35% SOC with a constant current of 6.2 C; Charging from 35% SOC to 40% SOC with a constant current of 5.7 C; Charging from 40% SOC to 45% SOC with a constant current of 5.2 C; Charging from 45% SOC to 50% SOC with a constant current of 4.8 C; Charging from 50% SOC to 55% SOC with a constant current of 4.6 C; Charging from 55% SOC to 60% SOC with a constant current of 4.4 C; Charging from 60% SOC to 65% SOC with a constant current of 4.2 C; Charging from 65% SOC to 70% SOC with a constant current of 3.9 C; Charging from 70% SOC to 75% SOC with a constant current of 3.5 C; Charging from 75% SOC to 80% SOC with a constant current of 3.0 C. Charging from 80% SOC to 100% SOC with a constant current of 0.33 C.

[0300] Minor variations in charging time between 10% and 80% SOC for battery cells in different embodiments and comparison examples can be achieved by slight adjustments to the charging rates mentioned above. Overall, the charging rate decreases progressively from low to high SOC. The specific charging rates are listed in Tables 1 and 2. 3. The test steps for the volumetric energy density (VED) of the battery cells are as follows:

[0301] The battery cells in the exemplary embodiments and comparative examples are placed at 25°C and charged with a constant current of 0.33 C to 3.65 V, followed by a constant voltage charge at 3.65 V to 0.05 C, and left to rest for 30 minutes. They are then discharged with a constant current of 0.33 C to 2.0 V, and the discharge capacity A0 at this time is recorded. Unit: Ah. The length, width, and height of the battery cell are measured with calipers, and the battery cell volume Vo is calculated. Unit: L. The volumetric energy density VED of the battery cell is VED = (A0 × discharge plateau voltage) / V0. Unit: Wh / L. III. Analysis of the test results for each embodiment and comparison example

[0302] Each embodiment and comparison example are produced separately using the above-mentioned method, and the performance parameters are measured, and the results are listed in the table below. Table 3 electrolyte solution cathode foil Nr. Mass fraction of ethylene carbonate Mass fraction of dimethyl carbonate Mass fraction of ethyl acetate Mass fraction of the first additive One-sided coating weight of the cathode film layer (mg / 1540.25mm²) 2 ) Mass fraction of the carbon element in lithium iron phosphate C Example 1 27,3% 11,7% 39,0% 6,0% 250 1,12% Example 2 27,3% 11,7% 39,0% 6,0% 214 1,12% Example 3 27,3% 11,7% 39,0% 6,0% 230 1,12% Example 4 27,3% 11,7% 39,0% 6,0% 307 1,12% Example 5 27,3% 11,7% 39,0% 6,0% 380 1,12% Example 6 28,4% 12,2% 40,5% 3,0% 250 1,12% Example 7 26,8% 11,5% 38,3% 7,5% 250 1,12% Example 8 28,0% 12,0% 40,0% 4,0% 250 1,12% Example 9 25,9% 11,1% 37,0% 10,0% 250 1,12% Example 10 27,3% 11,7% 39,0% 6,0% 250 0,92% Example 11 27,3% 11,7% 39,0% 6,0% 250 1,34% Example 12 27,3% 11,7% 39,0% 6,0% 250 1,71% Example 13 28,4% 44,6% 8,1% 3,0% 200 1,12% Comparative example 1 27,3% 11,7% 39,0% 6,0% 250 1,12% Comparative example 2 27,3% 11,7% 39,0% 6,0% 422 1,12% Comparative example 3 29,2% 12,5% 41,8% 0,5% 250 1,12% Comparative example 4 24,2% 10,4% 34,5% 15,0% 250 1,12% Table 4 Anode foil AWAY C / B Battery cell Nr. One-sided coating weight of the anode film layer (mg / 1540.25mm²) 2 ) Mass fraction of silicon-carbon composite particles in the first anode film layer Mass fraction of silicon-carbon composite particles in the second anode film layer Mass fraction of silicon element A Volumetric energy density (Wh / L) Capacity maintenance rate after 1000 cycles Charging time from 10% SOC to 80% SOC (min) Example 1 95 5,0% 5,0% 2,43% 0,41 0,19 425 88,90% 8,6 Example 2 95 1,0% 1,0% 0,49% 0,08 0,19 395 90,50% 8,0 Example 3 95 3,0% 3,0% 1,50% 0,25 0,19 408 89,60% 8,3 Example 4 95 12,0% 12,0% 5,80% 0,97 0,19 470 86,40% 9,1 Example 5 95 20,0% 20,0% 9,70% 1,62 0,19 510 84,60% 9,9 Example 6 95 5,0% 5,0% 2,43% 0,81 0,37 425 87,70% 8,2 Example 7 95 5,0% 5,0% 2,43% 0,32 0,15 425 89,20% 8,8 Example 8 95 12,0% 12,0% 5,80% 1,45 0,28 470 85,70% 8,9 Example 9 95 12,0% 12,0% 5,80% 0,58 0,11 470 87,20% 9,6 Example 10 95 5,0% 5,0% 2,43% 0,41 0,15 427 89,20% 8,6 Example 11 95 5,0% 5,0% 2,43% 0,41 0,22 421 88,60% 8,6 Example 12 95 5,0% 5,0% 2,43% 0,41 0,29 416 87,70% 8,6 Example 13 76 5,0% 5,0% 2,43% 0,81 0,37 410 88,70% 8,6 Comparative example 1 115 0,0% 0,0% 0,00% 0,00 0,19 390 83,60% 8,6 Comparative example 2 95 25,0% 25,0% 12,10% 2,02 0,19 533 78,60% 10,5 Comparative example 3 95 5,0% 5,0% 2,43% 4,86 2,24 425 863cls@60%SOH 8,0 Comparative example 4 95 5,0% 5,0% 2,43% 0,16 0,07 425 73,40% 9,8 (The specification 863cls@60%SOH in comparison example 3 means that the capacity retention rate of the battery cell in comparison example 3 is only 60% after 863 cycles)

[0303] Based on the above results, the battery cells in embodiments 1-13 comprise an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises a cathode foil, an anode foil, and a separating film, the separating film being located between the cathode foil and the anode foil, and wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, and wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises lithium-containing phosphate with an olivine structure, and wherein the one-sided coating weight of the cathode film layer is 180 mg / 1540.25 mm². 2 up to 380mg / 1540.25 mm 2is; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises an active anode material, wherein the active anode material comprises a silicon-based material, and wherein, based on the mass of the active anode material, the mass fraction of silicon is 0.3% to 10.0%; wherein the electrolyte solution comprises a first additive, wherein the first additive comprises ethylene carbonate and / or fluoroethylene carbonate, and wherein the mass fraction of the first additive is 1% to 12%.

[0304] A comparison of embodiments 1 to 13 with comparative example 1 shows that, compared to adjusting only the one-sided coating weight of the cathode film layer or the anode film layer, the present application achieves an improved energy density in the battery cell while maintaining its fast-charging capability by simultaneously adjusting the one-sided coating weight of the cathode film layer and the content of silicon-based elements in the anode film layer.

[0305] A comparison of embodiments 1 to 13 with comparative example 2 shows that controlling the silicon content in the silicon-based material between 0.3% and 10.0% improves both the cycle performance and the fast-charging capability of the battery cell.

[0306] A comparison of embodiments 1-13 with comparison examples 3-4 shows that controlling the mass fraction of the first additive between 1% and 12% improves the cycle performance of the battery cell while also taking into account its fast-charging capability.

[0307] A comparison of embodiments 1-4 with embodiment 5 shows that a mass fraction of silicon elements of 0.3% to 6.0% in the silicon-based material further improves the cycle performance and fast-charging capability of the battery cell.

[0308] Exemplars 1-3, 6-7 and 10-13 show that a mass fraction of the silicon element of 0.3% to 3% in the active anode material in conjunction with a mass fraction of the first additive of 2% to 7% in the electrolyte solution of the battery cell provides excellent cycle performance and fast charging capability.

[0309] From embodiments 4-5 and 8-9 it can be seen that the silicon content in the active anode material is greater than 3% and less than or equal to 6% and the mass fraction of the first additive in the electrolyte solution is 3% to 10%, giving the battery cell a high volumetric energy density.

[0310] As can be seen from embodiments 1-13, the ratio of the mass fraction A of the silicon element in the silicon-based material to the mass fraction B of the first additive is between 0.025 and 6. The battery cells exhibit high energy density, excellent cycle performance, and fast-charging capability.

[0311] From embodiments 1 and 10 to 12, it can be seen that the mass fraction of the carbon element relative to the mass of the lithium-containing carbonate with an olivine structure is 0.8% to 2.3%, which allows the battery cell to take into account excellent cycle performance and fast charging capability.

[0312] From embodiments 1 and 13, it can be seen that the electrolyte solution comprises a first organic solvent (ethylene carbonate and dimethyl carbonate) and a second organic solvent (ethyl acetate), and that, based on the total mass of the electrolyte solution, the mass fraction of the first organic solvent is 20% to 72%, giving the battery cell excellent cycle performance and fast charging capability. REFERENCE MARK LIST 1 battery pack 2 Upper Case 3 Lower Case 4 battery modules 5 Secondary battery 51 cases 52 Electrode component 53 Cover plate QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] Test standard GB / T30835-2014

[0125] Test standard GB / T 19077-2016

[0136] Standard GB / T 36363-2018

[0242]

Claims

[1] Battery cell, characterized by , that it comprises an electrode assembly and an electrolyte solution, wherein the electrode assembly comprises a cathode foil, an anode foil and a separating film, the separating film being located between the cathode foil and the anode foil, and wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on at least one side of the cathode collector, wherein the cathode film layer comprises an active cathode material, wherein the active cathode material comprises lithium-containing phosphate with an olivine structure, where the one-sided coating weight of the cathode film layer is 180mg / 1540.25 mm 2 up to 380mg / 1540.25 mm 2 amounts; wherein the anode foil comprises an anode collector and an anode film layer arranged on at least one side of the anode collector, wherein the anode film layer comprises an active anode material, wherein the active anode material comprises a silicon-based material, wherein the mass fraction of silicon is 0.3% to 10.0% relative to the mass of the active anode material; wherein the electrolyte solution comprises a first additive, wherein the first additive comprises at least one of ethylene carbonate and ethylene carbonate derivatives, and wherein the mass fraction of the first additive is 1% to 12% based on the total mass of the electrolyte solution, wherein the ethylene carbonate derivative comprises a compound represented by formula I: wherein R1, R2, R3 and R4 each independently comprise one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R1, R2, R3 and R4 are not simultaneously hydrogen atoms. [2] Battery cell according to claim 1, characterized by , that, relative to the mass of the active anode material, the mass fraction of the silicon element is 0.3% to 6.0%. [3] Battery cell according to claim 1 or 2, characterized by , that at least one of R1, R2, R3 and R4 comprises a fluorine atom. [4] Battery cell according to any one of claims 1 to 3, characterized by , that the ethylene carbonate derivative comprises one or more of the group consisting of fluorinated ethylene carbonate, difluoroethylene carbonate and trifluoromethylethylene carbonate. [5] Battery cell according to any one of claims 1 to 4, characterized by, that the battery cell satisfies the following relationship 0.025≤A / B≤6, optionally 0.035≤A / B≤2.5, where A represents the mass fraction of the silicon element relative to the mass of the active anode material; B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution. [6] Battery cell according to any one of claims 1 to 5, characterized by , that, based on the mass of the active anode material, the mass fraction of the silicon element is 0.3% to 3%; where, based on the total mass of the electrolyte solution, the mass fraction of the first additive is 2% to 7.5%. [7] Battery cell according to any one of claims 1 to 5, characterized by , that, based on the mass of the active anode material, the mass fraction of the silicon element is greater than 3% and less than or equal to 6%; wherein, based on the total mass of the electrolyte solution, the mass fraction of the first additive is 3% to 10%. [8] Battery cell according to any one of claims 1 to 7, characterized by , that the lithium-containing phosphate with an olivine structure comprises the following: a lithium-containing phosphate matrix, and a coating layer located on at least part of the surface of the lithium-containing phosphate matrix, wherein the coating layer contains a carbon element. [9] Battery cell according to claim 8, characterized by , that the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure is 0.8% to 2.3%. [10] Battery cell according to claim 8 or 9, characterized by , that the battery cell fulfills the following relationship: 0.08≤C / B≤1.15, where C represents the mass fraction of the carbon element relative to the mass of the lithium-containing phosphate with an olivine structure; where B represents the mass fraction of the first additive relative to the total mass of the electrolyte solution. [11] Battery cell according to any one of claims 8 to 10, characterized by that the coating layer continues to contain a substance Li 3-d1 Fe 2-d1 M3 d1 (PO m1 ) n1 includes where 0≤d1≤1, 3≤m1≤5 and 2≤n1≤4 hold; where M3 comprises one or more of the elements Ti, Zr, Hf, Ge and Sn, and M3 optionally has a valency of +4. [12] Battery cell according to any one of claims 8 to 11, characterized by that the lithium-containing phosphate matrix is ​​a compound of the general formula Li x1 A y1 Me a1 M 31 P 1-c1 X c1 Y z1 includes where 0.5≤x1≤1.3, 0≤y1≤1.3, 0.9≤x1+y1≤1.3, 0.9≤a1≤1.5, 0≤b1≤0.5, 0.9≤a1+b1≤1.5, 0≤c1≤0.5 and 3≤z1≤5 hold, where A includes at least one of Na, K and Mg; Me includes at least one of Mn, Fe, Co and Ni; M includes at least one 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; X includes at least one of S, Si, Cl, B, C, N, P; Y includes at least one of O, F. [13] Battery cell according to any one of claims 8 to 12, characterized by , that the lithium-containing phosphate matrix comprises one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium nickel phosphate, lithium cobalt phosphate and modified forms of any of the aforementioned substances, wherein the modified forms comprise one or more of doping modification and coating modification. [14] Battery cell according to any one of claims 1 to 13, characterized by , that the powder density of the active cathode material at 30,000 N is 2.43 g / cm³ 3 up to 2.85 g / cm³ 3 , optional 2.48 g / cm²3 up to 2.80 g / cm³ 3 , amounts. [15] Battery cell according to any one of claims 1 to 14, characterized by , that the density of the cathode film layer at a charge level of 100% is 2.50 g / cm³ 3 up to 2.80 g / cm³ 3 amounts. [16] Battery cell according to any one of claims 1 to 15, characterized by , that the active anode material comprises a carbon-based material, wherein the carbon-based material comprises graphite. [17] Battery cell according to claim 16, characterized by , that the graphite comprises composite graphite particles, wherein the composite graphite particles comprise graphite base particles and a carbon coating layer encasing the surface of the graphite base particles, wherein the graphite base particles comprise secondary particles, while the carbon coating layer comprises amorphous carbon. [18] Battery cell according to claim 16 or 17, characterized bythat the composite graphite particles meet at least one of the following conditions: (1) the mass fraction of amorphous carbon is 2% to 5% in relation to the total mass of the composite graphite particles; (2) the powder resistance of the composite graphite particles is 0.005 Ω·cm to 0.04 Ω·cm. [19] Battery cell according to any one of claims 16 to 18, characterized by , that the anode film layer comprises a first anode film layer and a second anode film layer, wherein the first anode film layer is arranged between the current collector and the second anode film layer, and wherein the first anode film layer and the second anode film layer each comprise the composite graphite particles. [20] Battery cell according to claim 19, characterized by, that the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is greater than or equal to the volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer. [21] Battery cell according to claim 20, characterized by , that the volume-averaged particle size Dv50 of the composite graphite particles in the first anode film layer is 8.5 µm to 14.8 µm, and / or that the volume-averaged particle size Dv50 of the composite graphite particles in the second anode film layer is 7.8 µm to 12.8 µm. [22] Battery cell according to any one of claims 19 to 21, characterized by , that, in relation to the total thickness of the first anode film layer and the second anode film layer, the thickness fraction of the second anode film layer is 30% to 70%. [23] Battery cell according to any one of claims 1 to 22, characterized by, that the anode foil further comprises an anode conductive layer located between the anode collector and the anode film layer on at least one side, wherein the anode conductive layer comprises a conductive means, wherein the conductive means comprises one or more from the group consisting of superconducting carbon, conductive graphite, acetylene carbon black, carbon black, ketjen carbon black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. [24] Battery cell according to claim 23, characterized by , that the anode conductive layer has a thickness of 0.5 µm to 2 µm. [25] Battery cell according to any one of claims 1 to 24, characterized by , that the density of the anode film layer at a charge level of 100% is 1.15 g / cm³ 3 up to 1.45 g / cm³ 3 is, and / or that the one-sided coating weight of the anode film layer is 70mg / 1540.25 mm 2 up to 135mg / 1540.25 mm 2 amounts; [26] Battery cell according to any one of claims 1 to 25, characterized by that the electrolyte solution further comprises an organic solvent, wherein the organic solvent comprises one or more of a first organic solvent and a second organic solvent, wherein the first organic solvent comprises at least one of a cyclic carbonate and a chain-like carbonate, optionally being a cyclic carbonate; wherein the second organic solvent comprises R5-COO-R6, wherein R5 comprises one from the group consisting of a hydrogen atom, a halogen atom, a C1-C5 alkyl and a C1-C5 halogenated alkyl, wherein R6 comprises one from the group consisting of a C1-C5 alkyl and a C1-C5 halogenated alkyl. [27] Battery cell according to claim 26, characterized bythat the cyclic carbonate comprises one or more from the group consisting of ethylene carbonate, propylene carbonate and butylene carbonate; and / or that the chain-like carbonate comprises one or more from the group consisting of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; and / or that the second organic solvent comprises one or more from the group consisting of methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate and ethyl butyrate. [28] Battery cell according to claim 26 or 27, characterized by , that, based on the total mass of the electrolyte solution, the mass fraction of the first organic solvent is 20% to 72%. [29] Battery cell according to any one of claims 1 to 28, characterized bythat the electrolyte solution further comprises a second additive, wherein the second additive comprises one or more from the group consisting of a sulfur-containing additive and a lithium salt additive. [30] Battery cell according to claim 29, characterized by , that the sulfur-containing additive comprises one or more from the group consisting of sulfate vinyl ester, bisulfate vinyl ester, sulfite butene ester, 1,3-propanesulfonic acid lactone, ethylene sulfite and methylenedisulfonic acid methyl ester; and / or wherein the lithium salt additive comprises one or more from the group consisting of lithium difluorophosphate, lithium difluorooxalate borate, lithium tetrafluoroborate and lithium dioxalate borate. [31] Battery cell according to any one of claims 1 to 30, characterized by that the electrolyte solution further comprises a lithium salt, wherein the lithium salt comprises one or two from the group consisting of fluorinated sulfonylimide salt and lithium hexafluorophosphate. [32] Battery cell according to claim 31, characterized by , that the fluorinated sulfonylimide salt comprises one or two from the group consisting of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide. [33] Battery cell according to claim 32, characterized by , that the lithium salt comprises lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate, wherein the molar concentration ratio of lithium bis(fluorosulfonyl)imide to lithium hexafluorophosphate is 0.2 to 1.

0. [34] Battery cell according to claim 33, characterized by , that the molar concentration of lithium bis(difluorosulfonyl)imide is 0.2 mol / L to 0.5 mol / L and the molar concentration of lithium hexafluorophosphate is 0.5 mol / L to 1.2 mol / L. [35] Battery cell according to any one of claims 1 to 34, characterized by that the separating film meets at least one of the following conditions: (1) the thickness of the separating film is 4 µm to 12 µm, optionally 5 µm to 9 µm; (2) the porosity of the separating film is 20% to 70%, optionally 35% to 60%. [36] Battery cell according to any one of claims 1 to 35, characterized by , that the battery cell is configured to have a charging time of 5 to 10.5 minutes from a charge level of 10% to a charge level of 80%. [37] Battery cell according to any one of claims 1 to 36, characterized by that the volumetric energy density of the battery cell is between 395 Wh / L and 530 Wh / L. [38] Battery device comprising a battery cell according to any one of claims 1 to 37. [39] Battery device according to claim 38, characterized by , that the battery device is configured to have a charging time of 5 to 10.5 minutes from a charge level of 10% to a charge level of 80%. [40] Power-consuming device comprising a battery device according to claim 38 or 39.

Images