A battery cell, a battery unit and an electrical device

Abstract

A battery cell comprising a positive electrode plate, a negative electrode plate, and an electrolyte solution, wherein the electrolyte solution contains a solvent comprising a chain-like carboxylic acid ester solvent, wherein the conductivity of the electrolyte solution is 13 mS / cm to 20 mS / cm, wherein the negative electrode plate comprises a negative current collector and a negative membrane layer arranged on at least one side of the negative current collector, wherein the negative membrane layer comprises a negative electrode material which exhibits a characteristic peak of the phosphorus element 2p with a binding energy between 132 eV and 138 eV in an X-ray photoelectron spectrum (XPS).

Description

Technical field

[0001] The present application relates to the field of a battery cell, in particular a battery cell, a battery unit and an electrical device. State of the art

[0002] In recent years, battery cells have been widely used in energy storage systems for hydropower, firepower, wind power and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and many other areas.

[0003] With the market's increasing demands for energy efficiency in electrical appliances and for lifespan under harsh environmental conditions, higher demands are also being placed on the dynamic properties and high-temperature stability of battery cells. However, with current technologies, it is difficult to improve these properties simultaneously, which represents a pressing technical challenge in this field. Description of the invention

[0004] The present application was carried out taking into account the above-mentioned task and aims to provide a battery cell and an electrical device that both ensure the dynamic properties of the battery cell and improve its high-temperature stability.

[0005] A first aspect of the present application provides a battery cell comprising a positive electrode plate, a negative electrode plate, and an electrolyte solution. The electrolyte solution contains a solvent comprising a chain-like carboxylic acid ester solvent, the conductivity of the electrolyte solution being 13 mS / cm to 20 mS / cm. The negative electrode plate comprises a negative current collector and a negative membrane layer arranged on at least one side of the negative current collector. The negative membrane layer comprises a negative electrode material exhibiting a characteristic peak of the phosphorus element 2p with a binding energy between 132 eV and 138 eV in an X-ray photoelectron spectrum (XPS).Electrolyte solutions containing chain-like carboxylic acid ester solvents with a conductivity of 13 mS / cm to 20 mS / cm are advantageous for improving the dynamic properties of battery cells. However, chain-like carboxylic acid ester solvents are often highly reactive and continuously attack the solid electrolyte membrane (SEI membrane) between the negative electrode and the electrolyte solution during storage. This leads to continuous degradation and regeneration of the SEI membrane and a continuous increase in DC internal resistance during battery cell storage. The SEI membrane contains a phosphorus element, which improves its corrosion resistance and thermal stability at high temperatures, ensuring both the dynamic performance and storage stability of the battery cell.

[0006] In one embodiment, the characteristic peak of the phosphorus element 2p comprises a first phosphorus-containing subpeak with a binding energy of 133 eV to 134.5 eV and / or a second phosphorus-containing subpeak with a binding energy of 136 eV to 137.5 eV.

[0007] The characteristic peak of the phosphorus element 2p can be either a single peak with a peak maximum or multiple peaks with multiple peak maxima. Regardless of whether it is a single peak or multiple peaks, the XPSpeak software is used to perform a peak fitting to the characteristic peak of the P2p spectrum in order to identify subpeaks. The standard spectra and the analysis of the electron split energies show that the first subpeak, with a binding energy of 133 eV to 134.5 eV, corresponds to the phosphorus element in Li. x PO y F zThis corresponds to the second subpeak with a binding energy of 136 eV to 137.5 eV, while the second subpeak corresponds to the phosphorus element in Li. x0 PF z0 This corresponds to where x is 1 to 3, y is 2 to 6, and z is 0 to 6, where x0 is 1 to 3 and z0 is 1 to 6. The phosphorus-containing components in the aforementioned SEI membrane can improve the corrosion resistance and thermal stability of the SEI membrane on the surface of the negative electrode material at high temperatures and improve the kinetic properties and storage stability of the battery cell.

[0008] In one embodiment, the negative electrode material in X-ray photoelectron spectroscopy (XPS) comprises a characteristic peak of the fluorine element 1s with a binding energy between 684.5 eV ~ 686 eV.

[0009] The standard spectra and the analysis of the electron splitting energies show that the fluorine-containing subpeak with a binding energy of 684.5 eV to 686 eV corresponds to the fluorine element in Li x PO y F z or Li x0 PF z0 The aforementioned fluorinated components in the SEI membrane can improve the corrosion resistance and thermal stability of the SEI membrane at high temperatures and improve the kinetic properties and storage stability of the battery cell.

[0010] In one embodiment, the negative membrane layer on the surface facing away from the negative current collector comprises an inorganic phosphorus-containing component with the general formula Li x PO y F z and / or with the general formula Li x0 PF z0 , where x is 1 to 3, y is 2 to 6, z is 0 to 6, x0 is 1 to 3 and z0 is 1 to 6.

[0011] In one embodiment, the electrolyte solution contains a phosphorus-containing additive, wherein the phosphorus-containing additive optionally comprises one or more of the following substances: lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO2F2), trimethylsilyl phosphate (TMSP), triphenylphosphone (TPPO), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN), N-(triphenylphosphinyl)aniline (TPPA), diethyl phenylphosphonic acid ester (DEPP), triphenyl phosphite (TPPi), diphenyl phosphite methyl ester (MDP), triethyl phosphite (TEP) and N,N-diallyldiethylphosphamide (DADEPA).

[0012] In one embodiment, the phosphorus-containing additive comprises one or more of the following substances: lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO₂F₂), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN), N-(triphenylphosphinyl)aniline (TPPA), diethyl phenylphosphonate (DEPP), and triphenyl phosphite (TPPi). Phosphorus-containing additives often exhibit high potential. When added to the electrolyte solution, phosphorus-containing additives react primarily during formation or subsequent cycles, developing into phosphorus-containing components in the SEI membrane, thereby increasing the storage stability of the battery cell. It is conceivable that in some embodiments, the phosphorus-containing additives added to the electrolyte solution are completely converted into phosphorus-containing components of the SEI membrane during formation.In some embodiments, phosphorus-containing additives remain in the electrolyte solution and reinforce the SEI membrane during the subsequent cycling process of the battery cell.

[0013] In one embodiment, the phosphorus-containing additive further comprises a fluorine element, wherein the phosphorus-containing additive optionally comprises one or more of lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO2F2), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN).

[0014] The above-mentioned phosphorus-containing additives contain both phosphorus and fluorine elements and readily develop into inorganic phosphorus-containing components with the general formula Li during formation and the first cycle process. x PO y F z and / or inorganic phosphorus-containing components with the general formula Li x0 PF z0in the SEI membrane, effectively ensuring both the kinetic properties and the high-temperature stability of the battery cell.

[0015] In one embodiment, the mass fraction of the phosphorus-containing additive in the electrolyte solution of the battery cell is 0.1% to 3%, based on the total mass of the electrolyte solution.

[0016] The mass fraction of the phosphorus-containing additive in the electrolyte solution of the aforementioned battery cell lies within the range mentioned above, whereby the electrolyte solution promotes the reinforcement of the SEI membrane during the cycle process, while simultaneously ensuring the dynamic properties and storage stability of the battery cell.

[0017] In one embodiment, the volume distribution particle size is Dv50 negativ of the negative electrode material 7.8 µm to 14.3 µm.

[0018] The negative active material with Dv50 NegativsWithin the aforementioned area, it contains a certain proportion of both small and large particles, which allows the small particles to increase the transport rate of lithium ions and improve the dynamic properties of the battery cell, while the size distribution of the particles increases the compaction density of the electrode plate of the battery cell, improves the energy density of the battery cell, and allows a balance between dynamic properties and energy density to be achieved.

[0019] In one embodiment, the volume distribution of the particle size Dv50 negativ of the negative electrode material 7.8 µm to 10.8 µm, and the mass fraction of the phosphorus-containing additive in the electrolyte solution is 0.3% to 1.8%.

[0020] The negative active materials with a particle size distribution Dv50 negativIn the aforementioned area, the diffusion distance of lithium ions in the solid phase can be shortened, thus improving the dynamic properties of the battery cell. However, the negative active materials with a volume distribution of particle size Dv50 exhibit negativ In the aforementioned area, they exhibit a relatively large surface area and high surface activity and react relatively strongly with chain-like carboxylic acid ester solvents. Therefore, a higher concentration of phosphorus-containing additives in the electrolyte solution is required to ensure both dynamic performance and storage stability.

[0021] In one embodiment, the volume distribution of the particle size Dv50 negativ of the negative active material 10.8 µm to 14.3 µm, and the mass fraction of the phosphorus-containing additive in the electrolyte solution is 0.1% to 1.3%.

[0022] In one embodiment, the electrolyte solution also contains carbonate ester additives, wherein the carbonate ester additives comprise one or more of vinyl carbonate VC and fluoroethylene carbonate FEC.

[0023] The phosphorus-containing components on the surface of the negative electrode material increase the high-temperature stability of the SEI membrane, but also make it more brittle. Carbonate ester additives can develop into organic components within the SEI membrane, thereby increasing its toughness. Interacting with the phosphorus-containing components in the SEI membrane, this improves its stability during the battery cell's cycle life and extends the battery cell's cycle life.

[0024] In one embodiment, the electrolyte solution comprises vinyl carbonate VC and fluoroethylene carbonate FEC.

[0025] Chain-like carboxylic acid esters exhibit high activity, improve wettability between the electrolyte solution and the electrode plate, and increase the conductivity of the electrolyte solution. However, they can also attack the solid-state electrolyte membrane (SEI membrane). Vinyl carbonate (VC) has a similar reduction potential to chain-like carboxylic acid esters, inhibits their reactivity, increases the density of the SEI membrane, and improves the cycle life of the battery cell. The combination of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) ensures a balance between the battery's interfacial impedance and the high-temperature stability of the SEI membrane. Adding phosphorus-containing additives, vinyl carbonate (VC), and fluoroethylene carbonate (FEC) to the electrolyte solution allows for an even more effective harmonization of the battery cell's dynamic properties, storage stability, and cycle life.

[0026] In one embodiment, the mass fraction of the carbonate ester additive is 2% ~ 10%, optionally 3% ~ 8%, based on the total mass of the electrolyte solution.

[0027] The electrolyte solution with a mass fraction of carbonate ester additives within the above-mentioned range can both improve the cycle stability of the SEI membrane and control the extent of side reactions, thereby improving the overall cycle life of the battery cell.

[0028] In one embodiment, the mass fraction of vinyl carbonate (VC) in the electrolyte solution, based on the total mass of the electrolyte solution, is 1.5% to 8%, optionally 2% to 6.5%.

[0029] In one embodiment, the mass fraction of fluoroethylene carbonate (FEC) in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.1% to 4%, optionally 0.5% to 3%.

[0030] By adding vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the electrolyte solution, the dynamic properties and cycle stability of the battery cell can be effectively harmonized.

[0031] In one embodiment, the positive electrode plate comprises a positive current collector and a positive membrane layer located on at least one surface of the positive current collector, wherein the positive membrane layer comprises a positive active material comprising one or more lithium-containing phosphates with olive stone structure, lithium-containing transition metal oxides.

[0032] In one embodiment, the specific surface area of ​​the positive active material is 5.0 m². 2 / g ~ 9.4 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 2% - 6%.

[0033] In one embodiment, the specific surface area of ​​the positive active material is 9.5 m². 2 / g ~ 18 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 3% ~ 8%.

[0034] Positive active materials with a large specific surface area have a large contact area with the electrolyte solution, which can improve the kinetic properties of the battery cell. However, these materials tend to absorb water molecules from the air more readily, and these water molecules are difficult to remove from the positive membrane layer during the drying process. During the battery cell's cycling process, hydrofluoric acid is generated by the reaction of water molecules with electrolyte salts in the electrolyte solutions. This acid attacks the SEI membrane on the surface of the negative electrode material. Positive active materials with a high specific surface area produce high concentrations of hydrofluoric acid within the battery cell.The addition of high-content carbonate ester additives can improve the density of the SEI membrane on the surface of the negative electrode material, thereby ensuring both the dynamic performance and the cycle stability of the battery cell.

[0035] In one embodiment, the positive active material comprises a lithium-containing phosphate with an olive stone structure, the composition of which is represented by the general formula I: Li x1 A y1 Me a1 M b1 P 1-c1 X c1 Y z1 Formula 1 where: 0.5 ≤ x1 ≤ 1.3, 0 ≤ y1 ≤ 1.3 and 0.7 ≤ x1 + y1 ≤ 1.3; 0.9 ≤ a1 ≤ 1.5, 0 ≤ b1 ≤ 0.5 and 0.9 ≤ a1 + b1 ≤ 1.5; 0 ≤ c1 ≤ 0.5, 3 ≤ z1 ≤ 5; A comprises one or more of the elements Na, K, Mg; Me comprises one or more of the elements Mn, Fe, Co, Ni; M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; X comprises one or more of the elements S, Si, Cl, B, C, N; Y comprises one or more of the elements O, F. Lithium-containing phosphates with an olive stone structure, containing the above-mentioned components, exhibit good structural stability and cause only minor irreversible losses during fast charging, thereby improving the cycle stability of the battery cell.

[0036] In one embodiment, the specific surface area of ​​the lithium-containing phosphate with the olive stone structure is 5.0 m². 2 / g ~ 18.0 m 2 / G.

[0037] In one embodiment, the positive active material comprises a lithium-containing transition metal oxide, the composition of which is represented by the general formula II: Li x2 A y2 Ni a2 Co b2 Mn c2 M2 (1-a2-b2-c2) Y z2 Formula II where: 0 ≤ x² ≤ 2.1, 0 ≤ y² ≤ 2.1 and 0.9 ≤ x² + y² ≤ 2.1; 0 ≤ a² ≤ 1, 0 ≤ b² ≤ 1, 0 ≤ c² ≤ 1 and 0.1 ≤ a² + b² + c² ≤ 1; 1.8 ≤ z² ≤ 3.5; A comprises one or more of the elements Na, K, Mg; M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; Y comprises one or more of the elements O, F.

[0038] In one embodiment, the specific surface area of ​​the lithium-containing transition metal oxide is 0.1 m². 2 / g up to 2 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 1% to 5%.

[0039] In one embodiment, the positive active material also comprises an ion-conducting layer arranged on the surface of the lithium-containing phosphate, containing carbon and iron elements, wherein the percentage mass fraction of the carbon element is 1–2% based on the total mass of the positive active material. The aforementioned ion-conducting layer can simultaneously improve the ionic conductivity and electrical conductivity of the positive active material, optimize the solid-phase transport rate of ions and electrons, and enhance the kinetic properties of the battery cell.

[0040] In one embodiment, the ion-conducting layer comprises a fast ion conductor with a NASICON structure, as shown in Equation III. Li 3-b3 Fe2-b3 M2 b3 (PO x3 ) y3 Formula III

[0041] In formula III, M2 comprises one or more of the elements Ti, Zr, Hf, Ge, and Sn. Optionally, M2 is +4 valency, 0 ≤ b3 ≤ 1, 3 ≤ x3 ≤ 5, 2 ≤ y3 ≤ 4.

[0042] Fast ion conductors with a NASICON structure feature numerous three-dimensional diffusion and transport channels for lithium ions and are characterized by high ionic conductivity and structural stability during repeated lithium discharge and insertion cycles. By applying an ion conductor with a NASICON structure to the surface of the lithium-containing phosphate, the transport rate of lithium ions during repeated lithium discharge and insertion cycles at the positive electrode end can be significantly increased, thereby improving the ionic conductivity of the positive active material and optimizing the kinetic properties of the corresponding battery cell.

[0043] In one embodiment, the positive membrane layer comprises a lithium supplement, wherein the lithium supplement comprises one or more of the following materials: ternary lithium supplements, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium para-silicate, lithium para-manganate, lithium tartrate and lithium citrate.

[0044] By adding lithium supplements to the positive active layer, the irreversible lithium loss during the electrochemical process can be compensated for, thereby increasing the overall capacity and energy density of the battery cell.

[0045] In one embodiment, the mass fraction of the lithium additive is 0.1% to 10% based on the total mass of the positive membrane layer.

[0046] In one embodiment, the negative electrode material comprises graphite.

[0047] In one embodiment, the graphite comprises composite graphite particles, wherein the composite graphite particles comprise main body particles and a coating arranged at least partially on the surface of the main body particles, wherein the main body particles comprise synthetic graphite, wherein the coating comprises amorphous carbon and the composite graphite particles comprise secondary particles.

[0048] The composite graphite particles comprising secondary particles and the surface coating comprising amorphous carbon promote the wettability of the electrolyte solution in the negative active layer of the electrode plate and contribute to improving the performance of the battery cell.

[0049] In one embodiment, the mass fraction of amorphous carbon in the coating of the composite graphite particles is 2% to 5%, based on the total mass of the composite graphite particles.

[0050] If the amorphous carbon content is within a suitable range, the composite graphite material can exhibit not only a high capacity per gram but also a high active ion solid-phase transport capability, which contributes to improving the kinetic properties of the battery cell.

[0051] In one embodiment, the specific powder resistance of the negative electrode material is less than or equal to 0.04 Ω·cm.

[0052] In one embodiment, the negative electrode material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N. 3 up to 1.8 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.75 g / cm³ 3 .

[0053] The negative electrode materials, with a powder compaction density within the appropriate range, enable a higher compaction density of the negative active layer, resulting in a higher energy density for the battery cell. Simultaneously, the original pore structure of the negative active layer is maintained during the cycling process, contributing to the sustained high kinetic performance of the battery cell throughout this cycle.

[0054] In one embodiment, the negative electrode material also comprises a silicon-based material, wherein the silicon-based material comprises at least one of silicon, silicon oxide and silicon-carbon composites; based on the total mass of the negative active material, the mass fraction of the silicon element in the silicon-based material is 0.3% to 10%, optionally 1% to 6%.

[0055] The introduction of silicon-based materials contributes to improving the energy density of battery cells. Silicon-based materials within the aforementioned mass range can ensure both the energy density and the cycle stability of the battery cell.

[0056] In one embodiment, the negative electrode material comprises a silicon-based material, and the mass fraction of the carbonate ester additive in the electrolyte solution is 3% - 10%.

[0057] Silicon-based materials tend to expand during the cycling process, leading to rupture of the SEI membrane on the surface of the negative electrode material. This increases the relative consumption of additives. The carbonate ester additives mentioned above can improve the sealing and regenerability of the SEI membrane while simultaneously ensuring the energy density and cycle stability of the battery cell.

[0058] In one embodiment, the negative membrane layer comprises a first negative membrane layer arranged on the surface of the negative current collector and a second negative membrane layer arranged on the side of the first negative membrane layer facing away from the negative current collector, the second negative membrane layer comprising composite graphite particles; optionally, the negative electrode material in the first negative membrane layer comprises one or more of composite graphite particles and natural graphite.

[0059] The composite graphite particles are arranged near the electrolyte solution side to improve the kinetic properties of the battery cell while ensuring energy density.

[0060] In one embodiment, the ratio of the thickness of the second negative active material layer to the thickness of the first negative active material layer is 3:7 to 7:3.

[0061] In one embodiment, the volume-averaged particle size Dv501 of the negative active material in the first negative active material layer is 9.5 µm ~ 18.5 µm, optionally 9.5 µm ~ 14.8 µm.

[0062] In one embodiment, the volume-averaged particle size Dv502 of the negative active material in the second negative active layer is 7.8 µm ~ 14.3 µm, optionally 7.8 µm ~ 12.8 µm.

[0063] The second negative active material layer on the electrolyte solution side contains negative active materials with smaller particle size, which can further improve the solid-liquid transport rate of ions in the cell electrode plate and enhance the kinetic properties of the battery cell.

[0064] In one embodiment, the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 7.8 µm ~ 10.8 µm, and the mass fraction of the carbonate ester additive in the electrolyte solution is 3% ~ 8%.

[0065] In one embodiment, the mass fraction of the added vinyl carbonate (VC) in the electrolyte solution is 3% to 7% and the mass fraction of the added fluoroethylene carbonate (FEC) is 0.5% to 2%.

[0066] In one embodiment, the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 10.8 µm ~ 14.8 µm, and the mass fraction of the added carbonate ester additive in the electrolyte solution is 2% ~ 7%.

[0067] The relatively small volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer promotes solid-phase diffusion of lithium ions in the negative active electrode material. However, it also increases the reactivity of the negative active electrode material with chain-like carboxylic acid ester solvents and intensifies the degradation of the SEI membrane. By adjusting additives with a relatively high carbonate ester content, the density and regenerability of the SEI membrane on the surface of the negative electrode material can be increased, thus improving the cycle stability of the battery cell.

[0068] In one embodiment, the mass fraction of the added vinyl carbonate (VC) in the electrolyte solution is 2% to 6% and the mass fraction of the added fluoroethylene carbonate (FEC) is 0.5% to 2.5%.

[0069] In one embodiment, the mass fraction of the chain-like carboxylic acid ester is 25.5% to 63.75%, based on the total mass of the electrolyte solution.

[0070] In one embodiment, the chain-like carboxylic acid ester has the general structural formula R1-COO-R2, wherein R1 and R2 each independently comprise at least one of C1~C5 alkyl and C1~C5 haloalkyl.

[0071] In one embodiment, the chain-like carboxylic acid ester comprises one or more of ethyl butyrate, ethyl propionate, ethyl acetate, methyl acetate and methyl formate.

[0072] Electrolyte solutions with a mass fraction of chain-like carboxylic acid esters within the above-mentioned range exhibit good conductivity, wettability and chemical stability, which contributes to a comprehensive improvement in the kinetic properties, storage stability and cycle stability of the battery cell.

[0073] In one embodiment, the solvent also comprises carbonate ester solvents, wherein the mass fraction of the carbonate ester solvent, based on the total mass of the solvent of the electrolyte solution, is 17% - 76.5%, optionally 21.25% - 59.5%.

[0074] In one embodiment, the carbonate ester solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate.

[0075] In the electrolyte solution, carbonate ester solvents readily form a solvated structure with lithium ions in lithium-containing electrolyte salts, thereby increasing the dissociation rate of lithium ions and anions in lithium-containing electrolyte salts and thus improving the kinetic properties of the battery cell.

[0076] In one embodiment, the carbonate ester solvent comprises ethylene carbonate, wherein the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester is 0.27:1 - 1.33:1.

[0077] Chain-like carboxylic acid esters can increase the wettability between the electrolyte solution and the electrode plate, improving the solid-liquid transport rate of lithium ions between the electrolyte solution and the electrode plate. Simultaneously, the addition of chain-like carboxylic acid esters also contributes to increasing the conductivity of the electrolyte solution. However, chain-like carboxylic acid esters readily react with the SEI membrane, which impairs the storage stability of the battery cell. Ethylene carbonate in the electrolyte solution readily forms a solvated structure with lithium ions in lithium-containing electrolyte salts, thereby increasing the dissociation rate of lithium ions and anions in lithium-containing electrolyte salts. However, with increasing ethylene carbonate content, the viscosity of the electrolyte solution also increases, which negatively affects the conductivity of the electrolyte solution.The mass ratio of ethylene carbonate to the aforementioned chain-like carboxylic acid esters within the above-mentioned range ensures that the electrolyte solution simultaneously exhibits a suitable viscosity, conductivity, as well as a good dissociation rate and wettability, which contributes to a comprehensive improvement of the kinetic properties and high-temperature stability of the battery cell.

[0078] In one embodiment, the electrolyte solution comprises lithium salts, and the carbonate ester solvents comprise ethylene carbonate, wherein the mass ratio between the lithium salts and the ethylene carbonate is 0.29 - 0.72.

[0079] Ethylene carbonate in the electrolyte solution and lithium ions in lithium-containing electrolyte salts within the above-mentioned range can increase the dissociation rate of lithium ions and improve the kinetic properties of the battery cell.

[0080] In one embodiment, the electrical conductivity of the electrolyte solution is 13 mS / cm - 20 mS / cm, optionally 15 mS / cm - 20 mS / cm.

[0081] An electrolyte solution with a conductivity within the aforementioned range can better harmonize the dynamic properties and high-temperature stability of the battery cell.

[0082] In one embodiment, the lithium salt comprises one or more fluorosulfonylimide salts and lithium hexafluorophosphate (LiPF6). Optionally, the fluorosulfonylimide salt comprises one or more lithium difluorosulfonylimide (LiFSI) and lithium trifluoromethylsulfonylimide (LiTFSI).

[0083] Fluorosulfonylimide salts tend to decompose readily in electrolyte solutions, increasing the electrolyte's conductivity. Furthermore, fluorosulfonylimide salts exhibit high chemical stability, do not decompose readily during cyclic operation, reduce hydrogen fluoride formation during battery cycling, and decrease the likelihood of side reactions at the negative electrode, thus increasing the battery cell's cycle stability. However, below a certain temperature threshold, fluorosulfonylimide salts undergo significant decomposition with rising battery cell temperature, releasing large amounts of heat and drastically increasing the risk of thermal instability. This safety risk is particularly pronounced in fast-charging batteries.Although lithium hexafluorophosphate gradually decomposes during the secondary cycle, producing hydrofluoric acid, the addition of lithium hexafluorophosphate significantly reduces the risk of thermal instability of the battery cell, thus keeping the risk within a manageable range and increasing battery safety.

[0084] In one embodiment, the lithium-containing electrolyte salt comprises lithium difluorosulfonylimide (LiFSI) and lithium hexafluorophosphate (LiPF6), wherein the molar concentration of lithium difluorosulfonylimide (LiFSI) in the electrolyte solution is 0.2 mol / L - 0.5 mol / L, and wherein the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution is 0.5 mol / L - 1.0 mol / L.

[0085] In one embodiment, the ratio of the molar concentration of lithium difluorosulfonylimide in the electrolyte solution to the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution is (2-5):10.

[0086] The molar concentration of lithium difluorosulfonylimide in the electrolyte solution and the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution are within the above-mentioned ranges, giving the battery cell both good kinetic performance and high safety.

[0087] In one embodiment, the battery cell further comprises a separating membrane, which includes a porous base membrane and a functional layer arranged on at least one side of the porous base membrane. The thickness of the porous base membrane is ≤ 12 µm and can optionally be less than or equal to 9 µm.

[0088] In one embodiment, the porosity of the porous base membrane in the separating membrane is 20% - 70%, optionally 35% - 60%.

[0089] In one embodiment, the functional layer comprises a first functional layer arranged on the negative electrode side of the porous base membrane and a second functional layer arranged on the positive electrode side of the porous base membrane, wherein the first functional layer comprises first inorganic particles, and wherein the second functional layer comprises composite particles, the composite particles comprising second inorganic particles and a non-fluorinated polymer, wherein the second inorganic particles adhere to the surface of the non-fluorinated polymer particles in the composite particles and / or are distributed within the non-fluorinated polymer particles.

[0090] Inorganic particles can increase the heat resistance of the first and second functional layers and improve the kinetic properties of the battery cell.

[0091] In one embodiment, the non-fluorinated polymer particles comprise acrylate copolymers.

[0092] In one embodiment, the liquid supply coefficient of the battery cell is 2.2 g / Ah - 3.1 g / Ah.

[0093] In one embodiment, the fast charging time of the battery cell from 10% SOC to 80% SOC is 6 min to 15 min.

[0094] The second aspect of this application provides a battery unit comprising the battery cell provided in the first aspect of this application. The battery unit comprises at least one of the following elements: a battery module, a battery pack, or an energy storage battery.

[0095] The third aspect of this application provides an electrical device comprising the battery cell provided in the first aspect of this application. Brief description of the characters Fig. Figure 1 shows the X-ray photoelectron spectrum of the phosphor element of the anode material according to an embodiment of the present application. Fig. Figure 2 shows the X-ray photoelectron spectrum of the fluorine element of the anode material according to an embodiment of this present application. Fig. Figure 3 is a schematic representation of a battery cell according to a further embodiment of the present application. Fig. 4 shows an exploded view of the battery cell according to an embodiment of the present application, which is described in Fig. 3 is shown. Fig. Figure 5 is a schematic representation of the battery module according to an embodiment of the present application. Fig. Figure 6 is a schematic representation of the battery pack according to an embodiment of the present application. Fig. 7 is an exploded view of the in Fig. 6 battery pack shown according to an embodiment of the present application. Fig. Figure 8 is a schematic representation of an electrical device using a battery cell according to an embodiment of the present application as a power source. Detailed description of the embodiments

[0096] The embodiments of the battery cell and the electrical device in the present application are described in detail below with appropriate reference to the figures. However, unnecessary details are omitted. For example, details relating to generally known facts and repetitions of essentially identical structures are left out. This is done to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the figures and the following explanations are intended to provide those skilled in the art with a comprehensive understanding of the present application and are not intended to limit the subject matter of the present claims.

[0097] The “range” disclosed in the present application is defined by a lower bound and an upper bound. The given range is defined by selecting a lower bound and an upper bound, the selected lower bound and upper bound determining the limits of the specific range. The range defined in this way may or may not include end values ​​and can be combined arbitrarily; that is, any lower bound can be combined with any upper bound to form a range. For example, if the ranges 60–120 and 80–110 are specified for a particular parameter, then the ranges 60–110 and 80–120 are to be expected. Furthermore, if the minimum range values ​​1 and 2 and the maximum range values ​​3, 4, and 5 are specified, then all of the following ranges are to be expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5.In this application, unless otherwise specified, the range of values ​​"ab" denotes a shorthand representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the range of values ​​"0-5" denotes all real numbers between 0 and 5 listed in this document, where 0-5 is merely a shorthand for these combinations of numbers. When a parameter is specified as an integer ≥ 2, this is equivalent to disclosing that parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0098] Unless otherwise stated, all embodiments and optional embodiments of this application may be combined to form new technical solutions.

[0099] Unless otherwise stated, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0100] Unless otherwise stated, all steps of this application may be carried out sequentially or in any order, with sequential execution being preferred. For example, the procedure includes steps (a) and (b), which means that the procedure may include steps (a) and (b) carried out sequentially, or steps (b) and (a) carried out sequentially. For example, the procedure may also include step (c), which means that step (c) may be included in the procedure in any order. For example, the procedure may include steps (a), (b), and (c), but also steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0101] Unless otherwise stated, the terms "comprise" and "contain" used in this application are to be understood as either open or closed. For example, the terms "comprise" and "contain" may mean that other, unlisted components may also be included, or that only the listed components are included.

[0102] Unless otherwise stated, the term "or" in this application is to be understood inclusively. For example, the phrase "A or B" means "A, B, or both A and B." More precisely, each of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist). To improve the dynamic properties of the battery cell, solvents with high conductivity, such as solvents from the group of chain carboxylic acid esters, are frequently added to the electrolyte solution to achieve rapid ion transport and reduce the likelihood of lithium precipitation.However, highly conductive solvents are often very reactive and continuously attack the solid electrolyte membrane (SEI membrane) on the surface of the negative electrode material during storage, leading to continuous degradation and regeneration of the SEI membrane during battery cell storage. This increases the DC resistance of the battery cell, resulting in a reduction of its stability.

[0103] Based on this, this application proposes a battery cell comprising a positive electrode plate, a negative electrode plate, and an electrolyte solution. The electrolyte solution contains a solvent comprising a chain-like carboxylic acid ester solvent, the conductivity of which is greater than or equal to 13 mS / cm. The negative electrode plate comprises a negative current collector and a negative membrane layer arranged on at least one side of the negative current collector. The negative membrane layer comprises a negative electrode material exhibiting a characteristic peak of the phosphorus element 2p with a binding energy between 132 eV and 138 eV in an X-ray photoelectron spectrum (XPS).

[0104] In this application, the X-ray photoelectron spectroscopy (XPS) of the negative electrode material can be tested using any method known in this field. For example, after disassembling the battery cell, the negative electrode end plate can be cleaned at least three times with a solvent such as dimethyl carbonate (DMC) before a powder sample is scraped off. The resulting negative electrode material powder is applied to a conductive substrate, and X-ray photoelectron spectroscopy measurements are performed using an X-ray photoelectron spectrometer (e.g., AXIS ULTRA). The scan rate and time of the X-ray source are adjusted to ensure focus and the detection of elements and functional groups at a depth of 5 nm to 10 nm below the surface of the negative electrode material.This yields the X-ray photoelectron spectrum (XPS) of the sample, in which the characteristic peaks of the elements are analyzed. Chain-like carboxylic acid ester solvents are organic molecules with a carboxylic acid ester group that exhibit a chain structure. Examples include ethyl butyrate, ethyl propionate, ethyl acetate, methyl acetate, and methyl formate.

[0105] The type and mass of solvents in the electrolyte solution can be determined by electrolyte analysis using established methods. For example, the electrolyte composition can be measured by liquid chromatography, UV spectrophotometry, UV-Vis photometry, etc. One method involves disassembling a battery cell, extracting the free electrolyte solution, diluting it 3- to 10-fold with acetonitrile to obtain the dilute electrolyte solution for testing, and using a GC-MS 3100 gas chromatograph for organic compounds to sample the diluted electrolyte solution and perform a complete qualitative analysis by scanning. The sampling temperature is 250 °C, and the scan range is between 35 µm and 270 µm.After completion of the analysis, a total ion chromatogram of the individual organic compounds is obtained. Based on the position of the peaks in the chromatogram, the corresponding organic compounds are identified, and the percentage proportions of each organic compound are calculated based on the peak area.

[0106] The conductivity of an electrolyte solution is its ability to describe the electrical conduction process that arises from the directed movement of positive and negative ions in a dissociated electrolyte solution within an electric field. It can be measured using any known method in this field. For example, approximately 100 mL of electrolyte solution sample is placed in a dry, clean, and corrosion-resistant sample container, which is tightly sealed and placed in a water bath at constant temperature. The sample is shaken periodically and brought to a temperature of 25 °C (within a tolerance of ±5 °C). Once the sample temperature has stabilized, its conductivity is measured using a standard conductivity meter.The conductivity meter is thoroughly cleaned with a calibration fluid, immersed vertically in the liquid to be measured, the test is started with a click, and the test results are recorded after a stabilization period of at least 10 seconds. In some embodiments, the conductivity of the electrolyte solution can be selected to be either 13 mS / cm, 14 mS / cm, 15 mS / cm, 16 mS / cm, 17 mS / cm, 18 mS / cm, 19 mS / cm, 20 mS / cm, 21 mS / cm, 22 mS / cm, 23 mS / cm, 24 mS / cm, 25 mS / cm, or a range between these two values.

[0107] Electrolyte solutions containing chain-like carboxylic ester solvents with a conductivity of 13 mS / cm to 20 mS / cm are advantageous for improving the dynamic properties of battery cells. However, chain-like carboxylic ester solvents are often highly reactive and continuously attack the solid electrolyte membrane (SEI membrane) on the surface of the negative electrode material during storage. This leads to continuous degradation and regeneration of the SEI membrane and a continuous increase in DC internal resistance during battery cell storage.The SEI membrane on the surface of the negative electrode material of the battery cell described in this application contains a phosphorus element, which improves the corrosion resistance and thermal stability of the SEI membrane at high temperatures and ensures both the dynamic performance and storage stability of the battery cell.

[0108] In some embodiments, the characteristic peak of the phosphorus element 2p comprises a first phosphorus-containing subpeak with a binding energy of 133 eV to 134.5 eV and / or a second phosphorus-containing subpeak with a binding energy of 136 eV to 137.5 eV.

[0109] The characteristic peak of the phosphorus element 2p can be either a single peak with a peak maximum or multiple peaks with multiple peak maxima. Regardless of whether it is a single peak or multiple peaks, the XPSpeak software is used to perform a peak fitting to the characteristic peak of the P2p spectrum in order to identify subpeaks. The standard spectra and the analysis of the electron split energies show that the first subpeak, with a binding energy of 133 eV to 134.5 eV, corresponds to the phosphorus element in Li. x PO y F z This corresponds to the second subpeak with a binding energy of 136 eV to 137.5 eV, while the second subpeak corresponds to the phosphorus element in Li. x0 PF z0This corresponds to where x represents 1 to 3, y represents 2 to 6, and z represents 0 to 6, with x0 representing 1 to 3 and z0 representing 1 to 6. The phosphorus-containing components in the aforementioned SEI membrane can improve the corrosion resistance and thermal stability of the SEI membrane on the surface of the negative electrode material at high temperatures and improve the kinetic properties and storage stability of the battery cell.

[0110] In some embodiments, the negative electrode material in X-ray photoelectron spectroscopy (XPS) includes a characteristic peak of the fluorine element 1s with a binding energy between 684.5 eV ~ 686 eV.

[0111] In some embodiments, the negative electrode material exhibits a characteristic peak of the fluorine element 1s with a binding energy between 684.5 eV and 686 eV in X-ray photoelectron spectroscopy (XPS) at a distance of 5 nm to 10 nm from the surface. This characteristic peak of the fluorine element 1s with a binding energy between 684.5 eV and 686 eV in the X-ray photoelectron spectrum (XPS) of the negative electrode material indicates that the SEI membrane contains fluorine elements on its surface. The aforementioned fluorine-containing components in the SEI membrane can increase the corrosion resistance and thermal stability of the SEI membrane on the surface of the negative electrode material at high temperatures and improve the kinetic properties and storage stability of the battery cell.

[0112] In some embodiments, the negative membrane layer on the surface facing away from the negative current collector comprises an inorganic phosphorus-containing component with the general formula Li x PO y F z and / or an inorganic phosphorus-containing component with the general formula Li x üPF z ü, where x is 1 to 3, y is 2 to 6, z is 0 to 6, x0 is 1 to 3, and z0 is 1 to 6. The XPS full-spectrum analysis of the negative electrode material shows that the cations at a distance of 5 nm to 10 nm from the surface of the negative electrode material are mainly lithium ions. From this, it can be deduced that the negative electrode material at a distance of 5 nm to 10 nm from the surface contains inorganic phosphorus-containing components with the general formula Li x PO y F z and inorganic phosphorus-containing components with the formula Li x0 PF z0 contains.

[0113] In some embodiments, x can optionally be 1, 2, 3 or a range of values ​​between any two, y can optionally be 2, 3, 4, 5, 6 or a range of values ​​between any two, z can optionally be 0, 1, 2, 3, 4, 5, 6 or a range of values ​​between any two, x0 can optionally be 1, 2, 3 or a range of values ​​between any two, z0 can optionally be 1, 2, 3, 4, 5, 6 or a range of values ​​between any two.

[0114] In some embodiments, the electrolyte solution contains a phosphorus-containing additive, the phosphorus-containing additive optionally comprising one or more of the following additives: lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO2F2), trimethylsilyl phosphate (TMSP), triphenylphosphone (TPPO), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN), N-(triphenylphosphinyl)aniline (TPPA), diethyl phenylphosphonic acid ester (DEPP), triphenyl phosphite (TPPi), diphenyl phosphite methyl ester (MDP), triethyl phosphite (TEP) and N,N-diallyldiethylphosphamide (DADEPA).

[0115] In some embodiments, the phosphorus-containing additive comprises one or more of the following substances: lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO2F2), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN), N-(triphenylphosphinyl)aniline (TPPA), diethyl phenylphosphonic acid ester (DEPP) and triphenylphosphite (TPPi).

[0116] Additives are components present in small amounts in the electrolyte solution, typically comprising no more than 10% of the total mass of the electrolyte solution. They are characterized by high precision and low dosage, and can significantly improve battery performance in a specific range without altering the production process.

[0117] The components of the additives can be tested using any method known in this field, such as liquid chromatography, UV spectrophotometry, UV-Vis spectrophotometry, etc. The composition of the electrolyte solution can be determined. For example, the content of inorganic substances in the electrolyte solution can be determined using an ion chromatograph (IC). For this purpose, a specific quantity of electrolyte solution (with a dilution concentration in the middle of the standard curve) is weighed out, made up to 100 mL with ultrapure water, and an automated sample is taken for testing by ion chromatography. The ion chromatogram is then examined for inorganic substances, and the corresponding types of inorganic substances are identified based on the peak positions in the chromatogram. The aforementioned free electrolyte solution is diluted 3- to 10-fold with acetonitrile to obtain the diluted electrolyte solution to be tested.Using a GC-MS 3100 gas chromatograph for organic compounds, the aforementioned diluted electrolyte solution is introduced into the instrument and subjected to a complete qualitative scan analysis at a sampling point temperature of 250 °C. Scan range: 35 µm to 270 µm. Upon completion of the analysis, the total ion current chromatograms of the individual organic compounds are obtained, and the corresponding types of organic compounds are identified based on the peak positions in the chromatogram. Phosphorus-containing additives often exhibit high potential. Phosphorus-containing additives added to the electrolyte solution react primarily during formation or subsequent cycles, developing into phosphorus-containing components in the SEI membrane, thereby increasing the storage stability of the battery cell.It is understandable that in some embodiments, the phosphorus-containing additives added to the electrolyte solution are completely converted into phosphorus-containing components of the SEI membrane during formation. In other embodiments, phosphorus-containing additives remain in the electrolyte solution and reinforce the SEI membrane during the subsequent cycling process of the battery cell.

[0118] In some embodiments, the phosphorus-containing additive further comprises a fluorine element, wherein the phosphorus-containing additive optionally comprises one or more of lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluorophosphate (LiPO2F2), pentafluoro(phenoxy)cyclotriphosphonitrile (PFPN).

[0119] The above-mentioned phosphorus-containing additives contain both phosphorus and fluorine elements and readily develop into inorganic phosphorus-containing components with the general formula Li during formation and the first cycle process.x PO y F z and / or inorganic phosphorus-containing components with the general formula Li x0 PF z0 in the SEI membrane, effectively ensuring both the kinetic properties and the high-temperature stability of the battery cell.

[0120] In some embodiments, the mass fraction of the sulfur-containing additive in the electrolyte solution of the battery cell is 0.1% to 3%, based on the total mass of the electrolyte solution.

[0121] In some embodiments, the mass fraction of the phosphorus-containing additive, based on the total mass of the electrolyte solution, can optionally be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or a range between any two values.

[0122] The type and mass of phosphorus-containing additives in the electrolyte solution can be determined by electrolyte analysis using established methods. For example, the composition of the electrolyte solution can be determined by liquid chromatography, UV spectrophotometry, UV-Vis spectrophotometry, etc. For instance, the content of inorganic substances in the electrolyte solution is tested using an ion chromatograph (IC) by weighing out a specific quantity of the electrolyte solution (with a dilution concentration at the midpoint of the standard curve), making it up to 100 mL with ultrapure water, and then using an automated sampling point on the ion chromatograph for testing.The ion chromatogram of the inorganic substances is tested. The corresponding types of inorganic substances are compared based on the position of the peaks in the chromatogram, and the percentage content of the respective inorganic ions is calculated based on the peak area. The aforementioned free electrolyte solution is diluted 3 to 10 times with acetonitrile to obtain the electrolyte solution to be tested. Using a GC-MS 3100 gas chromatograph for organic compounds, the aforementioned diluted electrolyte solution is introduced into the instrument and subjected to a complete qualitative scan analysis. The sampling temperature is 250 °C, and the scan range is 35 µm to 270 µm. After completion of the test, a complete ion chromatogram of the individual organic substances is obtained.Based on the position of the peaks in the chromatogram, the corresponding types of organic substances are compared, and the corresponding percentage content of each organic substance is calculated based on the peak area. The mass of the calculated phosphorus-containing additive is divided by the mass of the electrolyte sample to obtain the mass fraction of the phosphorus-containing additive in the battery cell's electrolyte solution. It is understood that the mass fraction of the phosphorus-containing additive in the battery cell's electrolyte solution is somewhat lower than the mass fraction of the phosphorus-containing additive that was added to the battery cell's electrolyte solution.

[0123] The mass fraction of the phosphorus-containing additive in the electrolyte solution of the aforementioned battery cell lies within the range mentioned above, whereby the electrolyte solution promotes the reinforcement of the SEI membrane during the cycle process, while simultaneously ensuring the dynamic properties and storage stability of the battery cell.

[0124] In some embodiments, the volume distribution particle size is Dv50 negativ of the negative electrode material 7.8 µm to 14.3 µm.

[0125] The volume distribution of particle size Dv50 negativThe negative electrode material has a well-established meaning in this field and refers to the particle size corresponding to the cumulative volume fraction of the material at 50%. It can be measured using standard instruments and methods. For example, one can refer to GB / T 19077-2016 "Particle size distribution - Laser diffraction method" and conveniently perform the measurement with a laser particle size analyzer. The Mastersizer 3000 laser particle size analyzer from the British company Malvern Instruments Ltd. can be used as a test instrument.

[0126] In some embodiments, the volume distribution of the particle size Dv50 negativof the negative electrode material optional 7.8 µm, 7.9 µm, 8 µm, 8.1 µm, 8.2 µm, 8.3 µm, 8.4 µm, 8.5 µm, 8.6 µm, 8.7 µm, 8.8 µm, 8.9 µm, 9.0 µm, 9.1 µm, 9.2 µm, 9.3 µm, 9.4 µm, 9.5 µm, 9.6 µm, 9.7 µm, 9.8 µm, 9.9 µm, 10 µm, 10.1 µm, 10.2 µm, 10.3 µm, 10.4 µm, 10.5 µm, 10.6 µm, 10.7 µm, 10.8 µm, 11.8 µm, 12.8 µm, 13.8 µm, 14.3 µm oder ein Wertbereich zwischen den beliebigen beiden Werten sein.

[0127] Das negative active Material mit Dv50 NegativsWithin the aforementioned area, it contains a certain proportion of both small and large particles, which allows the small particles to increase the transport rate of lithium ions and improve the dynamic properties of the battery cell, while the size distribution of the particles increases the compaction density of the electrode plate of the battery cell, improves the energy density of the battery cell, and allows a balance between dynamic properties and energy density to be achieved.

[0128] In some embodiments, the volume distribution of the particle size is Dv50 negativ of the negative electrode material 7.8 µm to 10.8 µm, and the mass fraction of the phosphorus-containing additive in the electrolyte solution is 0.3% to 1.8%.

[0129] In some embodiments, the volume distribution of the particle size Dv50 negativof the negative electrode material optionally 7.8 µm, 7.9 µm, 8 µm, 8.1 µm, 8.2 µm, 8.3 µm, 8.4 µm, 8.5 µm, 8.6 µm, 8.7 µm, 8.8 µm, 8.9 µm, 9 µm, 9.1 µm, 9.2 µm, 9.3 µm, 9.4 µm, 9.5 µm, 9.6 µm, 9.7 µm, 9.8 µm, 9.9 µm, 10 µm, 10.1 µm, 10.2 µm, 10.3 µm, 10.4 µm, 10.5 µm, 10.6 µm, 10.7 µm, 10.8 µm, or a range between any two values, wherein the mass fraction of the phosphorus-containing additive in the electrolyte solution can be optionally 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, or a range between any two values. The negative active materials with a particle size distribution Dv50 negativ In the aforementioned area, the diffusion distance of lithium ions in the solid phase can be shortened, thus improving the dynamic properties of the battery cell. However, the negative active materials with a volume distribution of particle size Dv50 exhibit negativIn the aforementioned area, they exhibit a relatively large surface area and high surface activity and react relatively strongly with solvents for chain-like carboxylic acid esters. Therefore, a higher concentration of phosphorus-containing additives in the electrolyte solution is required to ensure both dynamic performance and storage stability.

[0130] In some embodiments, the volume distribution of the particle size is Dv50 negativ of the negative active material 10.8 µm ~ 14.3 µm, wherein the mass fraction of the phosphorus-containing additive in the electrolyte solution is 0.1 % ~ 1.3 %.

[0131] The volume distribution of particle size Dv50 negativof the negative active material optionally 10.8 µm, 10.9 µm, 11 µm, 11.1 µm, 11.2 µm, 11.3 µm, 11.4 µm, 11.5 µm, 11.6 µm, 11.7 µm, 11.8 µm, 12.8 µm, 13.8 µm, 14.3 µm or a range between any two values, wherein the mass fraction of the phosphorus-containing additive in the electrolyte solution optionally 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3% or a range can be between any two values.

[0132] In some embodiments, the electrolyte solution also contains carbonate ester additives, wherein the carbonate ester additives comprise one or more of the following substances: vinyl carbonate VC, fluoroethylene carbonate FEC.

[0133] In this application, the term “carbonate ester additives” refers to compounds containing a carbonate ester group (-O-CO-O-) and their derivatives, as well as mixtures containing the above-mentioned compounds and their derivatives.

[0134] The phosphorus-containing components on the surface of the negative electrode material increase the high-temperature stability of the SEI membrane, but also make it more brittle. Carbonate ester additives can develop into organic components within the SEI membrane, thereby increasing its toughness. Interacting with the phosphorus-containing components in the SEI membrane, this improves its stability during the battery cell's cycle life and extends the battery cell's cycle life.

[0135] In some embodiments, the electrolyte solution comprises vinyl carbonate VC and fluoroethylene carbonate FEC.

[0136] Chain-like carboxylic acid esters exhibit high activity, improve wettability between the electrolyte solution and the electrode plate, and increase the conductivity of the electrolyte solution. However, they can also attack the solid-state electrolyte membrane (SEI membrane). Vinyl carbonate (VC) has a similar reduction potential to chain-like carboxylic acid esters, inhibits their reactivity, increases the density of the SEI membrane, and improves the cycle life of the battery cell. The combination of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) ensures a balance between the battery's interfacial impedance and the high-temperature stability of the SEI membrane. Adding phosphorus-containing additives, vinyl carbonate (VC), and fluoroethylene carbonate (FEC) to the electrolyte solution allows for even more effective harmonization of the battery cell's dynamic properties, storage stability, and cycle life.

[0137] In some embodiments, the mass fraction of the carbonate ester additive is 2% ~ 10%, optionally 3% ~ 8%, based on the total mass of the electrolyte solution.

[0138] In some embodiments, the mass fraction of the carbonate ester additive, based on the total mass of the electrolyte solution, can optionally be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range between any two values.

[0139] The electrolyte solution with a mass fraction of carbonate ester additives within the above-mentioned range can both improve the cycle stability of the SEI membrane and control the extent of side reactions, thereby improving the overall cycle life of the battery cell.

[0140] In some embodiments, the mass fraction of vinyl carbonate (VC) in the electrolyte solution, based on the total mass of the electrolyte solution, is 1.5% to 8%, optionally 2% to 6.5%.

[0141] In some embodiments, based on the total mass of the electrolyte solution, the mass fraction of vinyl carbonate VC in the electrolyte solution can optionally be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% or a range between any two values.

[0142] In some embodiments, the mass fraction of fluoroethylene carbonate (FEC) in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.1% to 4%, optionally 0.5% to 3%.

[0143] In some embodiments, the mass fraction of fluoroethylene carbonate (FEC) in the electrolyte solution, based on the total mass of the electrolyte solution, can optionally be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or a range between any two values.

[0144] By adding vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the electrolyte solution, the dynamic properties and cycle stability of the battery cell can be effectively harmonized.

[0145] In some embodiments, the positive electrode plate comprises a positive current collector and a positive membrane layer located on at least one surface of the positive current collector, wherein the positive membrane layer comprises a positive active material comprising one or more of lithium-containing phosphates with olive stone structure, lithium-containing transition metal oxides.

[0146] In some embodiments, the specific surface area of ​​the positive active material is 5.0 m². 2 / g ~ 9.4 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 2% ~ 6%.

[0147] In this application, the specific surface area of ​​the positive active material has the meaning generally known in this field and can be measured using instruments and methods known in this field. For example, with reference to GB / T 19587-2017, the specific surface area can be tested by nitrogen adsorption analysis and calculated using the BET (Brunauer-Emmett-Teller) method. The Tri-Star 3020 pore size analyzer from Micromeritics in the USA can be used as the test instrument.

[0148] In some embodiments, the specific surface area S of the positive active material can optionally be 5 m². 2 / g, 5.4 m 2 / g, 6 m 2 / g, 6.4 m 2 / g, 7 m 2 / g, 7.4 m 2 / g, 8 m 2 / g, 8.4 m 2 / g, 9 m 2 / g, 9.4 m 2 / g or a range between either of the two values, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive added to the electrolyte solution can optionally be 2%, 3%, 4%, 5%, 6% or a range between either of the two values.

[0149] In some embodiments, the specific surface area of ​​the positive active material is 9.5 m². 2 / g ~ 18 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 3% ~ 8%.

[0150] In some embodiments, the specific surface area of ​​the positive active material can optionally be 9.5 m² 2 / g, 10 m 2 / g, 10.5 m 2 / g, 11 m 2 / g, 11.5 m 2 / g, 12 m 2 / g, 12.5 m 2 / g, 13 m 2 / g, 13.5 m 2 / g, 14 m 2 / g, 14.5 m 2 / g, 15 m 2 / g, 15.5 m 2 / g, 16 m 2 / g, 16.5 m 2 / g, 17 m 2 / g, 17.5 m 2 / g, 18 m 2 / g or a range between any two values, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive added to the electrolyte solution can optionally be 3%, 4%, 5%, 6%, 7%, 8% or a range between any two values.

[0151] Positive active materials with a large specific surface area have a large contact area with the electrolyte solution, which can improve the kinetic properties of the battery cell. However, these materials tend to absorb water molecules from the air more readily, and these water molecules are difficult to remove from the positive membrane layer during the drying process. During the battery cell's cycling process, hydrofluoric acid is generated by the reaction of water molecules with electrolyte salts in the electrolyte solutions. This acid attacks the SEI membrane on the surface of the negative electrode material. Positive active materials with a high specific surface area produce high concentrations of hydrofluoric acid within the battery cell.The addition of high-content carbonate ester additives can improve the density of the SEI membrane on the surface of the negative electrode material, thereby ensuring both the dynamic performance and the cycle stability of the battery cell.

[0152] In some embodiments, the positive active material comprises a lithium-containing phosphate with an olive stone structure, the composition of which is represented by the general formula I: Li x1 A y1 Me a1 M b1 P 1-c1 X c1 Y z1 Formula 1 where: 0.5 ≤ x1 ≤ 1.3, 0 ≤ y1 ≤ 1.3 and 0.7 ≤ x1 + y1 ≤ 1.3; 0.9 ≤ a1 ≤ 1.5, 0 ≤ b1 ≤ 0.5 and 0.9 ≤ a1 + b1 ≤ 1.5; 0 ≤ c1 ≤ 0.5; 3 ≤ z1 ≤ 5; A includes one or more of the elements Na, K, Mg; Me includes one or more of the elements Mn, Fe, Co, Ni; M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; X comprises one or more of the elements S, Si, Cl, B, C, N; Y comprises one or more of the elements O, F.

[0153] In some embodiments, x1 can optionally be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3 or a range between any two values; y1 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3 or a range between any two values; x1+y1 can be 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3 or a range between any two values; a1 can be 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 or a range between any two values. b1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5 or a range between any two values; a1+b1 can be 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 or a range between any two values; c1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5 or a range between any two values; z1 can be 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 or a range between any two values be..

[0154] Lithium-containing phosphates with olive stone structure, which contain the above-mentioned components, exhibit good structural stability and cause only minor irreversible losses during fast charging, thereby improving the cycle stability of the battery cell.

[0155] In some embodiments, the specific surface area of ​​the lithium-containing phosphate with the olive stone structure is 5.0 m². 2 / g ~ 18.0 m 2 / G.

[0156] In some embodiments, the specific surface area of ​​the lithium-containing phosphate with the olive stone structure can optionally be 5.0 m². 2 / g, 6.0 m 2 / g, 7.0 m 2 / g, 8.0 m 2 / g, 9.0 m 2 / g, 10.0 m 2 / g, 11.0 m 2 / g, 12.0 m 2 / g, 13.0 m 2 / g, 14.0 m 2 / g, 15.0 m 2 / g, 16.0 m 2 / g, 17.0 m 2 / g, 18.0 m 2 / g or a range of values ​​between any two.

[0157] In some embodiments, the positive active material comprises a lithium-containing transition metal oxide, the composition of which is represented by the general formula II: Li x2 A y2 Ni a2 Co b2 Mn c2 M2 (1-a2-b2-c2 )Y z2 Formula II where: 0 ≤ x² ≤ 2.1, 0 ≤ y² ≤ 2.1 and 0.9 ≤ x² + y² ≤ 2.1; 0 ≤ a² ≤ 1, 0 ≤ b² ≤ 1, 0 ≤ c² ≤ 1 and 0.1 ≤ a² + b² + c² ≤ 1; 1.8 ≤ z² ≤ 3.5; A comprises one or more of the elements Na, K, Mg; M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; Y comprises one or more of the elements O, F.

[0158] In some embodiments, x2 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or a range between any two values; y2 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or a range between any two values. both values, where x2+y2 can optionally be 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or a range between either of the two values; a2 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or a range between either of the two values;b2 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or a range between any two values; c2 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or a range between any two values; where a2+b2+c2 can optionally be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or a range between any two values; z2 can optionally be 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 or a range between any two values.

[0159] In some embodiments, the specific surface area of ​​the lithium-containing transition metal oxide is 0.1 m². 2 / g up to 2 m 2 / g, and based on the total mass of the electrolyte solution, the mass fraction of the carbonate ester additive in the electrolyte solution is 1% ~ 5%.

[0160] In some embodiments, the specific surface area of ​​the lithium-containing transition metal oxide can optionally be 0.1 m². 2 / g, 0.2 m 2 / g, 0.3 m 2 / g, 0.4 m 2 / g, 0.5 m 2 / g, 0.6 m 2 / g, 0.7 m 2 / g, 0.8 m 2 / g, 0.9 m 2 / g, 1 m 2 / g, 1.1 m 2 / g, 1.2 m 2 / g, 1.3 m 2 / g, 1.4 m 2 / g, 1.5 m 2 / g, 1.6 m 2 / g, 1.7 m 2 / g, 1.8 m 2 / g, 1.9 m 2 / g, 2 m 2The mass fraction of the carbonate ester additive added to the electrolyte solution can be 1%, 2%, 3%, 4%, 5%, or a range between these two values, based on the total mass of the electrolyte solution. In some embodiments, the positive active material also comprises an ion-conducting layer arranged on the surface of the lithium-containing phosphate, containing carbon and iron elements, wherein, based on the total mass of the positive active material, the percentage mass fraction of the carbon element is 1-2%.

[0161] In some embodiments, the percentage by mass of the carbon element, based on the total mass of the positive active material, can optionally be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or a range between any two values.

[0162] It should be noted that the ion-conducting layer can have both a single-layer and a multi-layer structure; that is, the iron-containing and carbon-containing components in the ion-conducting layer can be arranged either mixed or in layers. It is understood that the ion-conducting layer exhibits a high ion transport rate. The aforementioned carbon-containing ion-conducting layer can simultaneously improve the ionic conductivity and electrical conductivity of the positive active material, optimize the solid-phase transport rate of ions and electrons, and enhance the kinetic properties of the battery cell.

[0163] In some embodiments, the ion-conducting layer comprises a fast ion conductor with a NASICON structure, as shown in Equation III. Li 3-b3 Fe 2-b3 M2 b3 (PO x3 ) y3 Formula III

[0164] In formula III, M2 comprises one or more of the elements Ti, Zr, Hf, Ge, and Sn. Optionally, M2 is +4 valency, 0 ≤ b3 ≤ 1, 3 ≤ x3 ≤ 5, 2 ≤ y3 ≤ 4.

[0165] In some embodiments, b3 can optionally be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or a range between any two values; x3 can optionally be 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 or a range between any two values; y3 can optionally be 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4 or a range of values ​​between any two.

[0166] The phase structure in the ion-conducting layer can be characterized by any known method in this field. For example, characterizing the positive active material using transmission electron microscopy reveals that the ion-conducting layer and the matrix of the positive active material exhibit different phase structures. In combination with diffraction patterns and energy spectrum analyses, the fast ion-conducting component of the ion-conducting layer can be determined.

[0167] Fast ion conductors with a NASICON structure feature numerous three-dimensional diffusion and transport channels for lithium ions and are characterized by high ionic conductivity and structural stability during repeated lithium discharge and insertion cycles. By applying a fast ion conductor with a NASICON structure to the surface of the lithium-containing phosphate, the lithium ion transport rate during repeated lithium discharge and insertion cycles at the positive electrode end can be significantly increased, thereby improving the ionic conductivity of the positive active material and optimizing the kinetic properties of the corresponding battery cell.

[0168] In some embodiments, the fast ion conductor comprises one or more of the following compounds: Li2FeTi(PO4)3, Li2FeZr(PO4)3, Li2FeSn(PO4)3.

[0169] In some embodiments, the positive membrane layer comprises a lithium supplement, wherein the lithium supplement is one or more of the following materials: ternary lithium supplements, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium para-silicate, lithium para-manganate, lithium tartrate and lithium citrate.

[0170] Lithium supplements are typically materials that release active lithium during the electrochemical process to compensate for the irreversible loss of active lithium due to the growth of the SEI membrane of the negative electrode. Adding lithium supplements to the positive active layer can compensate for this irreversible lithium loss during the electrochemical process, thereby increasing the overall capacity and energy density of the battery cell.

[0171] Ternary lithium supplements refer to lithium supplements containing one or more oxides of nickel, cobalt, and manganese. In some embodiments, the mass fraction of the lithium supplement is 0.1% to 10% based on the total mass of the positive membrane layer.

[0172] In some embodiments, the mass fraction of the lithium additive, based on the total mass of the positive membrane layer, can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or a range between any two values.

[0173] The mass fraction of the lithium supplement in the aforementioned positive membrane layer is calculated by dividing the mass of the added lithium supplement by the total mass of the positive membrane layer.

[0174] In some embodiments, the negative active material comprises graphite.

[0175] In some embodiments, the graphite comprises composite graphite particles, wherein the composite graphite particles comprise main body particles and a coating arranged at least partially on the surface of the main body particles, wherein the main body particles comprise synthetic graphite, wherein the coating comprises amorphous carbon, and the composite graphite particles comprise secondary particles. Secondary particles are particles formed from two or more primary particles aggregated together.

[0176] The composite graphite particles comprising secondary particles and the surface coating comprising amorphous carbon promote the wettability of the electrolyte solution in the negative active layer of the electrode plate and contribute to improving the performance of the battery cell.

[0177] In some embodiments, the composite graphite material also includes kinetic carbon material.

[0178] In some embodiments, the kinetic carbon material is located between the primary particles of the main body and the primary particles. In this case, the main body particles of the negative active material comprise artificial graphite primary particles as well as the kinetic carbon material located between the primary particles.

[0179] In some embodiments, the kinetic carbon material is located within the coating. In this case, the coating comprises both the amorphous carbon material and the kinetic carbon material.

[0180] In some embodiments, the kinetic carbon material raw material comprises one or more of the following components: hard carbon, expanded graphite, and graphene.

[0181] In this document, "kinetic carbon material raw material" and "kinetic carbon material raw material powder" are completely identical in composition. "Kinetic carbon material" refers to the product obtained by graphitization and / or carbonization of the "kinetic carbon material raw material".

[0182] In some embodiments, the layer spacing of the crystal face of the kinetic carbon material (002) is d 002≥0.3358 nm, optionally 0.3359 nm ~ 0.3366 nm. The layer spacing of the kinetic carbon material raw materials is larger than that of conventional graphite (the layer spacing of conventional graphite is 0.335 nm). When the resulting kinetic carbon materials are uniformly distributed in the main body particles and / or the coating of the composite graphite particles, this promotes the rapid entry and exit of active ions, thereby improving the transport properties of active ions and electrons and thus enhancing the fast-charging characteristics of the battery cell.

[0183] In some embodiments, the mass fraction of amorphous carbon in the coating of the composite graphite particles is 2% to 5%, based on the total mass of the composite graphite particles.

[0184] In some embodiments, the mass fraction of amorphous carbon in the coating of the composite graphite particles, based on the total mass of the composite graphite particles, can optionally be 2%, 3%, 4%, 5% or a range between any two values.

[0185] If the amorphous carbon content is within a suitable range, the composite graphite material can exhibit not only a high capacity per gram but also a high active ion solid-phase transport capability, which contributes to improving the kinetic properties of the battery cell.

[0186] In some embodiments, the specific powder resistance of the negative electrode material is less than or equal to 0.04 Ω·cm.

[0187] In some embodiments, the specific powder resistance of the negative electrode material can optionally be 0.01 Ω·cm, 0.02 Ω·cm, 0.03 Ω·cm, 0.04 Ω·cm or a range of values ​​between these two.

[0188] The specific powder resistance of the negative electrode material can be tested using any method known in this field. As an example, the method previously described for testing the powder resistance of the positive active material can be used. For instance, a powder resistance meter (PRCD1100) can be used to perform the analysis and testing according to standard GB / T30835-2014.

[0189] In some embodiments, the negative electrode material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N. 3 up to 1.8 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.75 g / cm³ 3 .

[0190] In some embodiments, the powder compaction density of the negative electrode material under a pressure of 20000 N can optionally be 1.5 g / cm³. 3 , 1.55 g / cm³ 3 , 1.6 g / cm³ 3 , 1.65 g / cm³ 3 , 1.7 g / cm³ 3 , 1.75 g / cm³ 3 , 1.8 g / cm³ 3 or a range of values ​​between any two of these.

[0191] The powder compaction density of the negative electrode material under a pressure of 20,000 N is generally known in this field and can be measured using instruments and methods known in this field. For example, according to GB / T 24533-2009, the measurement can be carried out using an electronic pressure testing machine (e.g., an electronic pressure testing machine of type UTM7305). An exemplary test procedure is as follows: 1 g of powder of the negative active material is weighed and placed into a mold with a base area of ​​1.327 cm². 2Given, a pressure of 20000 N was applied, held under pressure for 30 seconds, then the pressure was released, held for 10 seconds, and subsequently the powder compaction density of the material under a pressure of 20000 N was recorded and calculated.

[0192] The negative electrode materials, with a powder compaction density within the appropriate range, enable a higher compaction density of the negative active layer, resulting in a higher energy density for the battery cell. Simultaneously, the original pore structure of the negative active layer is maintained during the cycling process, contributing to the sustained high kinetic performance of the battery cell throughout this cycle.

[0193] In some embodiments, the negative active material also comprises a silicon-based material, wherein the silicon-based material comprises at least one of silicon, silicon oxide and silicon-carbon composites; based on the total mass of the negative active material, the mass fraction of the silicon element in the silicon-based material is 0.3% to 10%, optionally 1% to 6%.

[0194] In some embodiments, the mass fraction of the silicon element in the silicon-based material, relative to the total mass of the negative active material, can be optionally 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range between these two values. The introduction of silicon-based materials contributes to improving the energy density of the battery cell. Silicon-based materials within the aforementioned mass range can ensure both the energy density and the cycle stability of the battery cell.

[0195] In some embodiments, the negative electrode material comprises a silicon-based material, and the mass fraction of the carbonate ester additive in the electrolyte solution is 3% to 10%.

[0196] In some embodiments, the mass fraction of the carbonate additive in the electrolyte solution can optionally be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range between any two values.

[0197] Silicon-based materials tend to expand during the cycling process, leading to rupture of the SEI membrane on the surface of the negative electrode material. This increases the relative consumption of additives. The carbonate ester additives mentioned above can improve the sealing and regenerability of the SEI membrane while simultaneously ensuring the energy density and cycle stability of the battery cell.

[0198] In some embodiments, the negative membrane layer comprises a first negative membrane layer arranged on the surface of the negative current collector and a second negative membrane layer arranged on the side of the first negative membrane layer facing away from the negative current collector, the second negative membrane layer comprising composite graphite particles; optionally, the negative electrode material in the first negative membrane layer comprises one or more of composite graphite particles and natural graphite.

[0199] The composite graphite particles are arranged near the electrolyte solution side to improve the kinetic properties of the battery cell while also taking energy density into account.

[0200] In some embodiments, the ratio of the thickness of the second negative active material layer to the thickness of the first negative active material layer is 3:7 to 7:3.

[0201] In some embodiments, the ratio of the thickness of the second negative active material layer to the thickness of the first negative active material layer can be optionally 3:7, 4:7, 5:7, 6:7, 1:1, 2:1, 7:3, or a range between these two values. In some embodiments, the volume-averaged particle size Dv501 of the negative active material in the first negative active material layer is 9.5 µm to 18.5 µm, optionally 9.5 µm to 14.8 µm.

[0202] In some embodiments, the volume-averaged particle size Dv501 of the negative active material in the first negative active material layer can optionally be 9.5 µm, 9.8 µm, 10 µm, 10.8 µm, 11 µm, 11.8 µm, 12 µm, 12.8 µm, 13 µm, 13.8 µm, 14 µm, 14.8 µm, 15 µm, 15.8 µm, 16 µm, 16.8 µm, 17 µm, 17.8 µm, 18 µm, 18.5 µm or a range of values ​​between any two of these.

[0203] In some embodiments, the volume-averaged particle size Dv502 of the negative active material in the second negative active layer is 7.8 µm ~ 14.3 µm, optionally 7.8 µm ~ 12.8 µm.

[0204] In some embodiments, the volume-averaged particle size Dv502 of the negative active material in the second negative active material layer can optionally be 7.8 µm, 8 µm, 8.8 µm, 9 µm, 9.8 µm, 10 µm, 10.8 µm, 11 µm, 11.8 µm, 12 µm, 12.8 µm, 13 µm, 13.8 µm, 14 µm, 14.3 µm or a range of values ​​between any two of these.

[0205] The volume-averaged particle sizes Dv501 and Dv502 of the negative active material in the first negative active material layer and the second negative active material layer can be tested according to the previously described test method for volume-averaged particle size.

[0206] The second negative active material layer on the electrolyte solution side contains negative active materials with smaller particle size, which can further improve the solid-liquid transport rate of ions in the cell electrode plate and enhance the kinetic properties of the battery cell.

[0207] In some embodiments, the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 7.8 µm to 10.8 µm, and the mass fraction of the carbonate ester additive in the electrolyte solution is 3% to 8%. In some embodiments, the volume-averaged particle size Dv502 of the negative electrode material in the second membrane layer can optionally be 7.8 µm, 8 µm, 8.8 µm, 9 µm, 9.8 µm, 10 µm, 10.8 µm, or a range between any two values, and the mass fraction of the carbonate additive added to the electrolyte solution can be 3%, 4%, 5%, 6%, 7%, 8%, or a range between any two values.

[0208] In some embodiments, the mass fraction of the added vinyl carbonate (VC) in the electrolyte solution is 3% to 7% and the mass fraction of the added fluoroethylene carbonate (FEC) is 0.5% to 2%.

[0209] In some embodiments, the mass fraction of the added vinyl carbonate VC in the electrolyte solution can optionally be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, or a range between any two values, while the mass fraction of the added fluoroethylene carbonate FEC can optionally be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or a range between any two values.

[0210] In some embodiments, the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 10.8 µm ~ 14.8 µm, and the mass fraction of the added carbonate ester additive in the electrolyte solution is 2% ~ 7%.

[0211] In some embodiments, the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer can optionally be 10.8 µm, 11 µm, 11.8 µm, 12 µm, 12.8 µm, 13 µm, 13.8 µm, 14 µm, 14.8 µm or a range between any two values, and the mass fraction of the added carbonate additive in the electrolyte solution can optionally be 2%, 3%, 4%, 5%, 6%, 7% or a range between any two values.

[0212] The relatively small volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer promotes solid-phase diffusion of lithium ions in the negative active electrode material. However, it also increases the reactivity of the negative active electrode material with chain-like carboxylic acid ester solvents and intensifies the degradation of the SEI membrane. By adjusting additives with a relatively high carbonate ester content, the density and regenerability of the SEI membrane on the surface of the negative electrode material can be increased, thus improving the cycle stability of the battery cell.

[0213] In some embodiments, the mass fraction of the added vinyl carbonate (VC) in the electrolyte solution is 2% to 6% and the mass fraction of the added fluoroethylene carbonate (FEC) is 0.5% to 2.5%.

[0214] In some embodiments, the mass fraction of the added vinyl carbonate VC in the electrolyte solution can be optionally 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, or a range between these two values. The mass fraction of the added fluoroethylene carbonate FEC can optionally be 0.5%, 1%, 1.5%, 2%, 2.5%, or a range between these two values.

[0215] In some embodiments, the mass fraction of the chain-like carboxylic acid ester is 25.5% to 63.75%, based on the total mass of the electrolyte solution.

[0216] In some embodiments, the mass fraction of the chain-like carboxylic acid ester, based on the total mass of the solvent in the electrolyte solution, can optionally be 25.5%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 63.75% or a range between any two values.

[0217] In some embodiments, the chain-like carboxylic acid ester has the general structural formula R l -COO-R2, wherein R1 and R2 each independently comprise at least one of the following groups: C1-C5 alkyl and C1-C5 haloalkyl. 'C1-C5 alkyl' means unbranched or branched alkyl groups with 1 to 5 carbon atoms, including, but not limited to, one or more of methyl, ethyl, propyl, isopropyl, n-butyl, i-butyl, m-butyl, t-butyl, n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl.

[0218] “C1-C5 halogenalkyl” refers to unbranched or branched alkyl groups with 1 to 5 carbon atoms in which at least one hydrogen atom is replaced by a halogen atom, including, but not limited to, one or more of chloroalkyl groups, bromoalkyl groups and iodoalkyl groups.

[0219] In some embodiments, the chain-like carboxylic acid ester comprises one or more of ethyl butyrate, ethyl propionate, ethyl acetate, methyl acetate, and methyl formate. Electrolyte solutions with a mass fraction of chain-like carboxylic acid esters within the aforementioned range exhibit good conductivity, wettability, and chemical stability, contributing to a comprehensive improvement in the kinetic properties, storage stability, and cycle stability of the battery cell.

[0220] In some embodiments, the solvent also comprises carbonate ester solvents, wherein the mass fraction of the carbonate ester solvent, based on the total mass of the solvent of the electrolyte solution, is 17% - 76.5%, optionally 21.25% - 59.5%.

[0221] In some embodiments, the solvent also comprises carbonate ester solvents, wherein, based on the total mass of the solvent in the electrolyte solution, the mass fraction of the carbonate ester solvent may optionally be 17%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 76.5% or any value in between.

[0222] In some embodiments, the carbonate ester solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate.

[0223] In the electrolyte solution, carbonate ester solvents readily form a solvated structure with lithium ions in lithium-containing electrolyte salts, thereby increasing the dissociation rate of lithium ions and anions in lithium-containing electrolyte salts and thus improving the kinetic properties of the battery cell.

[0224] In some embodiments, the carbonate ester solvent comprises ethylene carbonate, wherein the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester is 0.27:1 - 1.33:1.

[0225] In some embodiments, the carbonate ester solvent comprises ethylene carbonate, wherein the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester may be optionally 0.27:1, 0.30:1, 0.37:1, 0.40:1, 0.47:1, 0.50:1, 0.57:1, 0.60:1, 0.67:1, 0.70:1, 0.77:1, 0.80:1, 0.87:1, 0.90:1, 0.97:1, 1:1, 1.07:1, 1.17:1, 1.27:1, 1.33:1 or a range between any two values.

[0226] Chain-like carboxylic acid esters can increase the wettability between the electrolyte solution and the electrode plate, improving the solid-liquid transport rate of lithium ions between the electrolyte solution and the electrode plate. Simultaneously, the addition of chain-like carboxylic acid esters also contributes to increasing the conductivity of the electrolyte solution. However, chain-like carboxylic acid esters readily react with the SEI membrane, which impairs the storage stability of the battery cell. Ethylene carbonate in the electrolyte solution readily forms a solvated structure with lithium ions in lithium-containing electrolyte salts, thereby increasing the dissociation rate of lithium ions and anions in lithium-containing electrolyte salts. However, with increasing ethylene carbonate content, the viscosity of the electrolyte solution also increases, which negatively affects the conductivity of the electrolyte solution.The mass ratio of ethylene carbonate to the aforementioned chain-like carboxylic acid esters within the above-mentioned range ensures that the electrolyte solution simultaneously exhibits a suitable viscosity, conductivity, as well as a good dissociation rate and wettability, which contributes to a comprehensive improvement of the kinetic properties and high-temperature stability of the battery cell.

[0227] In some embodiments, the electrolyte solution comprises lithium salts, and the carbonate ester solvents comprise ethylene carbonate, wherein the mass ratio between the lithium salts and the ethylene carbonate is 0.29 - 0.72.

[0228] In some embodiments, the mass ratio between the lithium salt and the ethylene carbonate can optionally be 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72 or a range between any two values.

[0229] Ethylene carbonate in the electrolyte solution and lithium ions in lithium-containing electrolyte salts within the above-mentioned range can increase the dissociation rate of lithium ions and improve the kinetic properties of the battery cell.

[0230] In some embodiments, the electrical conductivity of the electrolyte solution is 13 mS / cm - 20 mS / cm; optionally it can be 15 S / cm - 20 mS / cm.

[0231] An electrolyte solution with a conductivity within the aforementioned range can better harmonize the dynamic properties and high-temperature stability of the battery cell.

[0232] In some embodiments, the lithium salt comprises one or more fluorosulfonylimide salts and lithium hexafluorophosphate (LiPF6). Optionally, the fluorosulfonylimide salt comprises one or more lithium difluorosulfonylimide (LiFSI) and lithium trifluoromethylsulfonylimide (LiTFSI).

[0233] Fluorosulfonylimide salts tend to decompose readily in electrolyte solutions, increasing the electrolyte's conductivity. Furthermore, fluorosulfonylimide salts exhibit high chemical stability, do not decompose easily during cyclic operation, reduce hydrogen fluoride formation during battery cycling, and decrease the likelihood of side reactions at the negative electrode, thereby increasing the battery cell's cycle stability. However, below a certain temperature threshold, fluorosulfonylimide salts undergo significant decomposition with rising battery cell temperature, releasing large amounts of heat and drastically increasing the risk of thermal instability. This safety risk is particularly pronounced in fast-charging batteries.Although lithium hexafluorophosphate gradually decomposes during the secondary cycle, producing hydrofluoric acid, the addition of lithium hexafluorophosphate significantly reduces the risk of thermal instability of the battery cell, thus keeping the risk within a manageable range and increasing battery safety.

[0234] In some embodiments, the lithium-containing electrolyte salt comprises lithium difluorosulfonylimide (LiFSI) and lithium hexafluorophosphate (LiPF6), wherein the molar concentration of lithium difluorosulfonylimide (LiFSI) in the electrolyte solution is 0.2 mol / L - 0.5 mol / L, and wherein the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution is 0.5 mol / L - 1.0 mol / L.

[0235] In some embodiments, the molar concentration of lithium difluorosulfonylimide (LiFSI) in the electrolyte solution can be optionally 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L or a range between any two values.

[0236] In some embodiments, the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution can be 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 or a range between any two values.

[0237] In some embodiments, the ratio of the molar concentration of lithium difluorosulfonylimide in the electrolyte solution to the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution is (2-5):10.

[0238] In some embodiments, the ratio of the molar concentration of lithium difluorosulfonylimide in the electrolyte solution to the molar concentration of lithium hexafluorophosphate LiPF6 in the electrolyte solution can optionally be 2:10, 3:10, 4:10, 5:10 or a range between these two values.

[0239] The molar concentration of lithium difluorosulfonylimide in the electrolyte solution and the molar concentration of lithium hexafluorophosphate (LiPF6) in the electrolyte solution are within the above-mentioned ranges, giving the battery cell both good kinetic performance and high safety.

[0240] In some embodiments, the battery cell also includes a separating membrane comprising a porous base membrane and a functional layer arranged on at least one side of the porous base membrane. The thickness of the porous base membrane is ≤ 12 µm and can optionally be less than or equal to 9 µm.

[0241] In some embodiments, the thickness of the porous base membrane can optionally be 5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm or a range between any two values.

[0242] In some embodiments, the porous base membrane comprises one or more of the following materials: glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The porous base membrane can be a single-layer membrane or a multi-layer composite membrane, without any particular restrictions.

[0243] In some embodiments, the porosity of the porous base membrane in the separating membrane is 20% - 70%, optionally 35% - 60%.

[0244] In some embodiments, the porosity of the porous base membrane in the separating membrane can optionally be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or a range between any two values.

[0245] In some embodiments, the functional layer comprises a first functional layer arranged on the negative electrode side of the porous base membrane and a second functional layer arranged on the positive electrode side of the porous base membrane, wherein the first functional layer comprises first inorganic particles, and wherein the second functional layer comprises composite particles, the composite particles comprising second inorganic particles and a non-fluorinated polymer, the second inorganic particles adhering to the surface of the non-fluorinated polymer particles and / or being distributed within the non-fluorinated polymer particles in the composite particles.

[0246] In some embodiments, the inorganic particles comprise one or more of silicon dioxide, aluminum oxide, borosilicate, barium sulfate, calcium oxide, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide and tin oxide.

[0247] Inorganic particles can increase the heat resistance of the first and second functional layers and improve the kinetic properties of the battery cell.

[0248] In some embodiments, the non-fluorinated polymer particles comprise acrylate copolymers.

[0249] In some embodiments, the liquid supply coefficient of the battery cell is 2.2 g / Ah - 3.1 g / Ah.

[0250] The fluid supply coefficient of a battery cell is the ratio between the mass of the electrolyte solution inside the battery cell and the battery capacity. The fluid supply coefficient of a battery cell can be tested using any known method. For example, the mass of the electrolyte solution in a battery cell can be determined by the following procedure: The battery is weighed and the mass recorded as M0. The battery cell is disassembled and the free electrolyte solution is poured out. The internal electrode components are removed, and the positive electrode plate, the negative electrode plate, the separating membrane, and the mechanical parts are separated.The positive electrode plate, the negative electrode plate, the separating membrane, and the mechanical parts are soaked and cleaned in dimethyl carbonate (DMC) for 24 to 48 hours, with the soaking process repeated at least three times. The positive electrode plate, the negative electrode plate, the separating membrane, and the mechanical parts are then dried in a 100 °C oven for at least 24 hours until completely dry. The dried positive electrode plate, the negative electrode plate, the separating membrane, and the mechanical parts are weighed, and the mass is recorded as M1. From this, the mass of the electrolyte solution in the battery cell is calculated as (M0 - M1). The fluid supply coefficient is calculated as (M0 - M1) / nominal capacity of the battery cell.The nominal capacity is the target capacity of the battery or is charged at a charging rate of 0.33 C to 3.65 V, then charged at a constant voltage of 3.65 V to 0.05 C, left to rest for 10 minutes and then discharged at a discharge rate of 0.33 C to 2.0 V, whereby the discharge capacity of the battery cell is used as the nominal capacity.

[0251] In some embodiments, the liquid supply coefficient of the battery cell can optionally be 2.2 g / Ah, 2.3 g / Ah, 2.4 g / Ah, 2.5 g / Ah, 2.6 g / Ah, 2.7 g / Ah, 2.8 g / Ah, 2.9 g / Ah, 3.0 g / Ah, 3.1 g / Ah or a range between any two of these values.

[0252] In some embodiments, the fast charging time of the battery cell from 10% SOC to 80% SOC is 6 min to 15 min.

[0253] The fast-charging time of the battery cell, charged from 10% SOC to 80% SOC, can be determined using any known method in this field. As an example, the battery cell is disassembled, and the positive and negative electrode plates, along with the free electrolyte solution, are removed and soaked and cleaned in dimethyl carbonate (DMC) for at least 72 hours. After the electrolyte solution solvent, lithium salt, and additives have been completely leached out, the positive and negative electrode plates are dried in a vacuum oven. Subsequently, copper wire is used as a reference electrode, the free electrolyte solution is added to the battery cell, and the positive and negative electrode plates are reassembled into a stacked three-electrode cell.At 30 °C, the stacked three-electrode cell is charged with a constant current of 0.33 C to a cutoff voltage of 3.65 V, then charged with a constant voltage to a current of 0.05 C, allowed to rest for 5 minutes, and then discharged with a constant current of 0.33 C to a discharge cutoff voltage of 2.5 V, with the actual capacity recorded as C0. The battery cell is then successively charged with constant currents of 0.5 C0, 1 C0, 1.5 C0, 2 C0, 2.5 C0, 3 C0, 3.5 C0, 4 C0, 4.5 C0, 5 C0, 5.5 C0, and 6 C0 until the reference electrode potential drops to 0 mV, recording the maximum charging rate at that state of charge (SOC). Using 5% SOC as an increment interval, the maximum charging rate is tested at each 5% SOC, e.g., B. 5% SOC, 10% SOC, 15% SOC to 100% SOC, where the maximum charging speed is recorded as C5% SOC, C10% SOC, C15% SOC to C100% SOC accordingly.The maximum charging speed at 10% SOC ~ 80% SOC, determined from this test, is used to calculate the continuous charging time at 10% SOC ~ 80% SOC, which corresponds to the fast charging time.

[0254] In some embodiments, the fast charging time of the battery cell charged from 10% SOC to 80% SOC can be optionally 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min or a range between any two of these values.

[0255] The battery cell has good kinetic properties and can meet the requirements for a more efficient energy supply for electrical devices.

[0256] In some embodiments, the battery cell may include an outer casing. This outer casing can be used to enclose the aforementioned electrode component and the electrolyte.

[0257] In some embodiments, the outer packaging of the battery cell can be a hard shell, for example, a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the battery cell can also be a soft packaging, for example, a soft pouch. The material of the soft packaging can be plastic, for example, polypropylene, polybutylene terephthalate, or polybutylene sulfate.

[0258] The present application is not subject to any special restrictions regarding the shape of the battery cell. The battery cell can be cylindrical, square, or any other shape. For example, the Fig. 3 a square battery cell 5 as an example.

[0259] In some embodiments, the outer packaging can be designed according to the Fig.4. The battery cell 5 comprises a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and the side plates together forming a receiving space. The housing 51 has an opening connected to the receiving space, and the cover plate 53 can be placed on the opening to close the receiving space. The positive electrode plate, the negative electrode plate, and the separating membrane can be formed into an electrode assembly 52 by a winding or stacking process. The electrode assembly 52 is encapsulated in the receiving space. The electrode assembly 52 is impregnated with electrolyte. The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, and those skilled in the art may make the selection according to the specific actual requirements.In some embodiments, the battery cell can be assembled into battery modules, where a battery module can contain one or more battery cells. The exact number can be selected by experts in this field according to the application and capacity of the battery module.

[0260] The Fig. Figure 5 shows an example of a battery module 4. As in the Fig. As shown in Figure 5, several battery cells 5 can be arranged sequentially along the longitudinal direction of the battery module 4. Of course, they can also be arranged in any other way. Furthermore, the multiple battery cells 5 can be secured by fastening elements.

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

[0262] In some embodiments, the aforementioned battery modules can also be assembled into a battery pack, which may contain one or more battery modules. The exact number can be selected by a person skilled in the art according to the application and capacity of the battery pack. Fig. 6 and Fig. Figure 7 shows an example of a battery pack 1. As can be seen from the Fig. 6 and Fig. As can be seen in Figure 7, the battery pack 1 can comprise a battery box and several battery modules 4 arranged within the battery box. The battery box comprises an upper box 2 and a lower box 3, the upper box 2 being able to be placed on top of the lower box 3 to form an enclosed space for the battery modules 4. The multiple battery modules 4 can be arranged within the battery box in any configuration.

[0263] The second aspect of this application provides a battery unit comprising the battery cell described in the first aspect of this application. The battery unit comprises at least one of the following elements: a battery module, a battery pack, or an energy storage battery.

[0264] Furthermore, this application also provides an electrical device comprising the battery cell described herein. The battery cell, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical 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] In some embodiments, the fast charging time of the electrical device from 10% SOC to 80% SOC is 6 minutes to 15 minutes.

[0266] In some embodiments, the fast charging time of the electrical device, charged from 10% SOC to 80% SOC, can be optionally 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, or a range between any two of these values.

[0267] Depending on the intended use, the electrical device in question can be a battery cell, battery module or battery pack.

[0268] The Fig. Figure 8 shows an example of an electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high performance and high energy density requirements of this electrical device, battery packs or battery modules can be used.

[0269] Another example of such an electrical device is mobile phones, tablets, laptops, etc. These devices usually need to be light and thin and can be powered by a battery cell as a power source. Example of implementation

[0270] To clarify the technical problems, solutions, and advantages of this application, further explanations are provided below with reference to exemplary embodiments and accompanying figures. It is understood that the described embodiments represent only a subset of the embodiments presented in this application and do not encompass all embodiments. The following description of at least one exemplary embodiment serves only for illustrative purposes and in no way constitutes a limitation of this application or its application. All other embodiments that a person skilled in the art in this field could derive from the embodiments presented in this application without any creative input fall within the scope of protection of this application.

[0271] Technical features or conditions not specified in the exemplary embodiments are to be understood in accordance with the technical features or conditions described in the technical literature or in the product descriptions. Unspecific reagents or instruments are commercially available products. Example 1: Production of the positive electrode plate:

[0272] The positive electrode plate comprises a positive current collector, a positive conductive layer on the positive current collector, and a positive membrane layer. The positive current collector consists of a 10 µm thick aluminum foil.

[0273] The positive conductive layer on the positive collector consists of a mixture of the positive conductivity agent superconducting carbon, the positive binder polyvinylidene fluoride (PVDF), and the solvent N-methylpyrrolidone (NMP). This mixture was applied uniformly to the surface of the collector and dried to form a membrane layer 1 µm thick. The mass fraction of the positive conductivity agent in the positive conductive layer is 40%, and the mass fraction of the positive binder is 60%.

[0274] The positive membrane layer consists of a membrane layer formed by uniformly applying a positive paste mass (solvent: N-methylpyrrolidone, NMP) to the surface of the positive conductive layer, drying, and cold pressing. The positive membrane layer comprises a positive active electrode material, a binder (polyvinylidene fluoride, PVDF), and a conductivity agent (acetylene carbon black) in a weight ratio of 97:2:1.

[0275] The positive active electrode material consists of lithium iron phosphate with a coating covering the surface of the lithium iron phosphate. The coating consists of lithium iron titanate phosphate (Li₂FeTi(PO₄)₃) and amorphous carbon. The Dv₅₀ value of the positive active electrode material is 1.6 µm, and the Dv₁₀ value is 0.64 µm.

[0276] The one-sided coating weight of the positive membrane layer is 300 mg / 1540.25 mm². 2 . Production of the negative electrode plate:

[0277] The negative electrode plate comprises a negative current collector, a negative conductive layer on the negative current collector, and a negative membrane layer. The negative current collector consists of a copper foil with a thickness of 5 µm.

[0278] The negative conductive layer on the negative current collector consists of the negative conductivity agent superconducting carbon, the negative binder styrene-butadiene rubber (SBR), the thickening agent sodium carboxymethylcellulose (CMC-Na), and water as a solvent in a mixture that is evenly applied to the surface of the negative current collector and allowed to dry to form a membrane layer 1 µm thick. The mass fraction of the negative conductivity agent in the negative conductive layer is 35%, the mass fraction of the negative binder in the negative conductive layer is 60%, and the mass fraction of the thickening agent in the negative conductive layer is 5%.

[0279] The negative membrane layer consists of a uniform coating of a negative paste (solvent: deionized water) on the surface of the negative conductive layer, which forms a membrane layer after drying and cold pressing. The one-sided coating weight of the negative membrane layer is 138 mg / 1540.25 mm². 2 .

[0280] The negative membrane layer comprises a first negative membrane layer and a second negative membrane layer, wherein the first negative membrane layer is located on the surface of the negative conductive layer and the second negative membrane layer is located on the surface of the first negative membrane layer.

[0281] The first negative membrane layer comprises graphite particles, the conductivity agent acetylene black, a first lithium-containing binder (lithium acrylate-acrylonitrile-acrylamide-hydroxyethyl ester copolymer, wherein the molar ratio of lithium acrylate monomer, acrylonitrile monomer, acrylamide monomer, and hydroxyethyl ester monomer is 35% : 30% : 15% : 20%), a negative binder styrene-butadiene rubber, and a thickening agent sodium carboxymethylcellulose in a mass ratio of 96.5:0.5:0.5:1.5:1, wherein the mass fraction of the lithium element in the first lithium-containing binder is 4.8%. The Dv50 of the graphite particles is 11.3 µm. The graphite particles consist of synthetic graphite and a carbon coating covering the surface of the synthetic graphite. The mass fraction of the carbon coating is 3.5%.

[0282] The second negative membrane layer comprises graphite particles, the conductivity agent acetylene black, a second lithium-containing binder (lithium acrylate-acrylonitrile-acrylamide-hydroxyethyl acetate copolymer, wherein the molar ratio of lithium acrylate monomer, acrylonitrile monomer, acrylamide monomer, and hydroxyethyl acetate monomer is 35% : 30% : 15% : 20%), an anode binder styrene-butadiene rubber, and a thickener sodium carboxymethylcellulose in a mass ratio of 97.5:0.5:0.5:0.5:1, with the mass fraction of lithium in the second lithium-containing binder being 4.8%. The Dv50 of the graphite particles is 11.3 µm. The graphite particles consist of synthetic graphite and a carbon coating covering the surface of the synthetic graphite. The mass fraction of the carbon coating is 3.5%.

[0283] In a glovebox with an argon atmosphere and a water content of <10 ppm, ethylene carbonate (EC), methyl ethyl carbonate (EMC), and ethyl acetate (EA) are mixed uniformly in a mass ratio of 35:15:50 to obtain an electrolyte solution. Lithium hexafluorophosphate (LiPF6) is slowly added as the lithium salt and stirred thoroughly until completely dissolved. After returning to room temperature, the additives vinyl carbonate (VC) at 2% by mass, fluoroethyl carbonate (FEC) at 2% by mass, and lithium difluorophosphate (LiPO2F2) at 1% by mass, based on the total mass of the electrolyte solution, are added successively and mixed thoroughly and uniformly to obtain the electrolyte solution. Based on the total mass of the electrolyte solution, the mass fraction of the lithium salt is 15%, and the conductivity of the electrolyte solution is 15.4 mS / cm. Production of the separation membrane

[0284] A first functional layer of nano-aluminum oxide is applied to the negative electrode side, while a layer of nano-aluminum oxide and a polyethylene (PE) film made of polyacrylic acid are applied to the other side as a separating membrane. The porous base membrane PE membrane has a porosity of 35% and a thickness of 7 µm. Battery cell manufacturing

[0285] The positive electrode plate, the separating membrane, and the negative electrode plate are stacked and wound sequentially to form a wound electrode assembly. This assembly is then placed in a square aluminum housing as outer packaging, dried, and subsequently filled with electrolyte. Following the steps of packaging, curing, formation, aging, repackaging, and capacity testing, the battery cell is obtained. The liquid conservation coefficient d3 / A of the battery cell is 2.9 g / Ah.

[0286] The manufacturing processes of embodiments 2 to 4 and 9 to 17 are essentially identical to those of embodiment 1, with the difference that the composition of the electrolyte solution has been adapted, as shown in Table 1.

[0287] The manufacturing process of embodiments 5 to 8 is essentially identical to that of embodiment 1, with the difference that the Dv50 values ​​of the negative active electrode material and / or the electrolyte components have been adapted.

[0288] The manufacturing processes of embodiments 18 to 21 are essentially identical to those of embodiment 1, with the difference that the Dv50 values ​​of the positive active electrode material and / or the electrolyte components have been adapted.

[0289] The manufacturing process in embodiment 22 is essentially identical to that in embodiment 1, with the difference that the type of positive active electrode material has been adapted. The ternary positive active electrode material in embodiment 22 is NCM811.

[0290] The manufacturing process in comparative example 1 is essentially the same as in embodiment 1, except that no phosphorus-containing additive is added to the electrolyte solution. Test procedure

[0291] The battery cells in the exemplary embodiments and comparison examples were each tested. The test results are listed in Table 1. (1) The procedure for the DCR test at high storage temperature is as follows: 1. Procedure for testing the DCR of the battery

[0292] The DCR test procedure can be carried out according to the methods in GB / T 31467 "Test procedures for the performance of high-performance lithium-ion batteries for HEVs". Specifically, the following applies: At 25 °C, the lithium-ion battery is charged to 3.65 V with a constant current of 0.33 C and left to rest for 1 minute, then charged to 3.65 V with a constant current of 0.1 C and left to rest for 30 minutes, discharged to 2.0 V with a constant current of 0.33 C, the discharge capacity A0 in Ah is recorded, and then charged to 0.5 A0 Ah with a constant current of 0.33 C to set the state of charge (SOC) to 50%.

[0293] The battery is stored at 25 °C for 2 hours, then discharged for 10 seconds at a constant current of 2C, where ΔU Entladung and ΔI Entladung The discharge DCR data of the lithium-ion battery are recorded. The discharge DCR data is calculated using the following formula: RDischarge=ΔUDischarge / ΔIDischarge

[0294] Here, ΔU denotes Entladung the voltage change within the first 10 seconds after the start of the discharge and ΔI Entladung denotes the current value within the first 10 seconds after the start of the discharge.

[0295] 2. Test procedure for storing batteries at high temperatures: First, the DCR value of the battery before storage at high temperatures is recorded as D0. Then, for a lithium battery cell, the lithium-ion battery is charged at 25 °C with a constant current of 0.33 C to 3.65 V, allowed to rest for 1 minute, then charged with a constant current of 0.1 C to 3.65 V, adjusted to 100% SOC, and subsequently stored at 60 °C. Every 30 days, the battery is removed and the DCR value is measured at 25 °C. This process is repeated, and the DCR values ​​of the battery after storage are recorded as D1, D2, ..., Dn. The DCR increase during storage is calculated as follows: (Dn - D0) / D0, where n represents 1, 2, 3, 4, ..., n.

[0296] In the present application, the DCR increase rate after 90 days of storage at 60 °C is stated as a test result. (2) Cycle count test at 60 °C:

[0297] At 60 °C, the battery is charged at a rate of 1C to 3.65 V of its nominal capacity, then charged at 3.65 V at a constant voltage to 0.05C, left to rest for 10 minutes, and then discharged at a rate of 1C to 2.5 V, again left to rest for 10 minutes. The charge and discharge process described above is considered one cycle. The test is terminated when the battery capacity has decreased to 80% of its original discharge capacity and is recorded as the number of cycles @80%SOH. (3) Test procedures for parameters in case of thermal instability of batteries: ① Load adjustment: At 25 °C, the lithium-ion battery is charged to 3.65 V with a constant current of 0.33 C and left to rest for 1 minute. It is then charged to 3.65 V with a constant current of 0.1 C and set to a state of charge (SOC) of 100%. 2. Overcharge and thermal instability test: The battery is secured with a clamping device for testing with a clamping force of 3000 N and then charged at a constant charging current rate of 1C until the thermal instability of the battery cell is reached. After the battery has cooled to room temperature, the state of the thermally unstable battery cell is observed. If a fire or explosion occurs, the thermal instability limit will deteriorate.

[0298] The test results are shown in Tables 1 to 3: Table 2 Consecutive number lithium salt Overcharging to the point of a thermally unstable battery Example 1 LiPF6 There was no fire and no explosion. Example 12 LiFSI Explosion, fire Example 13 70% LiPF 630% LiFSI There was no fire and no explosion. Table 3 Consecutive number Positive active material Specific surface materials m 1 / G Negative active material Dv50 around Conductivity of the electrolyte solution mS / cm Carboxylic acid ester solvents Masen fraction of the carboxylic acid ester 5 in the electrolyte solution Phosphorus-containing additive Mass aniel desphosphorus-containing additive Mass fraction of carbonate ester additive VC mass fraction FEC mass fraction lithium salt Number of cyclones BO%SOH at 60°C Example 1 lithium-containing phosphate: 4 2 11,5 15,4 Ettyl acetate 50% Lithium difluorophosphate 1,0% 4,0% 2,0% 2,0% LLPF6 1021 Example 9 lithium-containing phosphate: 14,2 11,5 116 Ethyl acetate 50% Lithium difluorophosphate 1,0% 2,0% 1,0% 1,0% LLPF6 732 Example of implementation 10 lithium-containing phosphate: 14,2 11,5 15,1 Ethyl acetate 50% Lithium difluorophosphate 1,0% 10,0% 8,0% 2,0% LLPF6 1376 Example of implementation 11 lithium-containing phosphate: 14,2 11,5 15,4 Ethyl acetate 50% Lithium difluorophosphate 1,0% 4,0% 1,0% 3,0% LLPF6 879 Test results

[0299] The surface of the negative membrane layer of the battery cell, after chemical formulation, is subjected to an XPS test. In the exemplary embodiments, the negative electrode end plate exhibits a characteristic peak at 132 eV to 138 eV in the X-ray electron spectrum (XPS) of the phosphorus cell 2p, whereas in comparison examples 1 and 2, no characteristic peak is observed in the X-ray electron spectrum (XPS) of the phosphorus cell 2p. Compared to the comparison examples, the battery cell in the exemplary embodiments exhibits good high-temperature stability.

[0300] With the exception of embodiment 4, the negative electrode plates in the other embodiments also exhibit characteristic peaks in the range of 684.5 eV to 686 eV in the electron-X-ray photon (XPS) spectrum of the fluorine cell 1s. The tests mentioned above show that the negative membrane layer in the battery cell in the embodiments contains inorganic phosphorus-containing components with the general formula Li on the surface facing away from the negative current collector. x PO y F z and / or the general formula Li x0 PF z0 contains, where x is 1 to 3, y is 2 to 6, z is 0 to 6, x0 is 1 to 3 and z0 is 1 to 6.

[0301] From the comparison of embodiments 1, 9 to 11, it can be seen that the battery cell can achieve a good balance between high-temperature storage properties and cycle stability if the mass fraction of ethylene carbonate in the electrolyte solution is between 2% and 6% and the mass fraction of fluoroethylene carbonate is between 0.5% and 2.5%.

[0302] It should be noted that the present disclosure is not limited to the embodiments mentioned above. The embodiments mentioned above serve only as examples. All embodiments that exhibit an essentially identical technical idea and achieve the same effect within the scope of the present disclosure also fall within its technical scope. Furthermore, all variants that a person skilled in the art in this field might conceive, as well as other embodiments formed by combining some elements of the embodiments, also fall within the scope of the present disclosure, provided they do not deviate from the main purpose of the present disclosure. Reference symbol list 1 battery pack 2 upper box 3 lower box 4 battery modules 5 battery cells 51 cases 52 Electrode assembly 53 Cover plate arrangement 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 patent literature

[0000] GB 19077-2016

[0125] Cited non-patent literature

[0000] Standard GB / T30835-2014

[0188]

Claims

[1] A battery cell comprising a positive electrode plate, a negative electrode plate and an electrolyte solution, wherein the electrolyte solution contains a solvent comprising a chain-like carboxylic acid ester solvent, wherein the conductivity of the electrolyte solution is 13 mS / cm to 20 mS / cm, wherein the negative electrode plate comprises a negative current collector and a negative membrane layer arranged on at least one side of the negative current collector, wherein the negative membrane layer comprises a negative electrode material which exhibits a characteristic peak of the phosphorus element 2p with a binding energy between 132 eV and 138 eV in an X-ray photoelectron spectrum (XPS). [2] A battery cell according to claim 1, characterized by, that the characteristic peak of the phosphorus element 2p comprises a first phosphorus-containing subpeak with a binding energy of 133 eV to 134.5 eV and / or a second phosphorus-containing subpeak with a binding energy of 136 eV to 137.5 eV. [3] A battery cell according to claim 1, characterized by , that the negative electrode material in X-ray photoelectron spectroscopy (XPS) includes a characteristic peak of the fluorine element 1s with a binding energy between 684.5 eV ~ 686 eV. [4] A battery cell according to any one of claims 1 to 3, characterized by , that the negative membrane layer on the surface facing away from the negative current collector contains an inorganic phosphorus-containing component with the general formula Li x PO y F z and / or with the general formula Li x0 PF z0 includes, where x is 1 to 3, y is 2 to 6, z is 0 to 6, x0 is 1 to 3 and z0 is 1 to 6. [5] A battery cell according to any one of claims 1 to 4, characterized by , that the electrolyte solution contains a phosphorus-containing additive, wherein the phosphorus-containing additive optionally comprises one or more of the following substances: Lithium difluorobis(oxalato) phosphate, lithium difluorophosphate, trimethylsilyl phosphate, triphenylphosphone, pentafluoro(phenoxy)cyclotriphosphonitrile, N-(triphenylphosphinyl)aniline, diethyl phenylphosphonate, triphenyl phosphite, diphenyl phosphite methyl ester, triethyl phosphite and N,N-diallyldiethyl phosphamide. [6] A battery cell according to claim 5, characterized by , that the phosphorus-containing additive comprises one or more of the following substances: Lithium difluorobis(oxalato)phosphate, lithium difluorophosphate, pentafluoro(phenoxy)cyclotriphosphonitrile, N-(triphenylphosphinyl)aniline, phenylphosphonic acid diethyl ester and triphenylphosphite. [7] A battery cell according to claim 5 or 6, characterized by, that the phosphorus-containing additive further comprises a fluorine element, wherein the phosphorus-containing additive optionally comprises one or more of lithium difluorobis(oxalato)phosphate, lithium difluorophosphate, pentafluoro(phenoxy)cyclotriphosphonitrile. [8] A battery cell according to any one of claims 1 to 7, characterized by , that the mass fraction of the phosphorus-containing additive in the electrolyte solution of the battery cell is 0.1% to 3%, based on the total mass of the electrolyte solution. [9] A battery cell according to any one of claims 1 to 8, characterized by that the volume distribution particle size Dv50 negativ The thickness of the negative electrode material is 7.8 µm to 14.3 µm. [10] A battery cell according to claim 9, characterized by , that the volume distribution of the particle size Dv50 negativ of the negative electrode material is 7.8 µm to 10.8 µm, with the mass fraction of the phosphorus-containing additive in the electrolyte solution being 0.3% to 1.8%. [11] A battery cell according to claim 9, characterized by that the volume particle size Dv50 negativ of the negative active material is 10.8 µm ~14.3 µm, with the mass fraction of the phosphorus-containing additive in the electrolyte solution being 0.1% ~1.3%. [12] A battery cell according to any one of claims 1 to 11, characterized by that the electrolyte solution also contains carbonate ester additives, wherein the carbonate ester additives comprise one or more of vinyl carbonate and fluoroethylene carbonate. [13] A battery cell according to claim 12, characterized by that the electrolyte solution includes vinyl carbonate and fluoroethylene carbonate. [14] A battery cell according to claim 12 or 13, characterized by , that the mass fraction of the carbonate ester additive is 2% ~ 10%, optionally 3% ~ 8%, based on the total mass of the electrolyte solution. [15] A battery cell according to any one of claims 12 to 14, characterized by, that the mass fraction of vinyl carbonate in the electrolyte solution, based on the total mass of the electrolyte solution, is 1.5% to 8%, optionally 2% to 6.5%. [16] A battery cell according to any one of claims 12 to 15, characterized by , that the mass fraction of fluoroethylene carbonate in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.1% to 4%, optionally 0.5% to 3%. [17] A battery cell according to any one of claims 1 to 16, characterized by , that the positive electrode plate comprises a positive current collector and a positive membrane layer located on at least one surface of the positive current collector, wherein the positive membrane layer comprises a positive active material comprising one or more of lithium-containing phosphates with olive stone structure, lithium-containing transition metal oxides. [18] A battery cell according to claim 17, characterized bythat the specific surface area of ​​the positive active material is 5.0 m² 2 / g ~ 9.4 m 2 / g, and wherein the mass fraction of the carbonate ester additive in the electrolyte solution, based on the total mass of the electrolyte solution, is 2% ~ 6%. [19] A battery cell according to claim 17, characterized by that the specific surface area of ​​the positive active material is 9.5 m² 2 / g ~ 18 m 2 / g, and wherein the mass fraction of the carbonate ester additive in the electrolyte solution is 3% ~ 8%, based on the total mass of the electrolyte solution. [20] A battery cell according to any one of claims 17 to 19, characterized by , that the positive active material comprises a lithium-containing phosphate with an olive stone structure, the composition of which is represented by the general formula I: Li x1 A y1 Me a1 M b1 P 1-c1 X c1 Y z1 Formula 1 where: 0.5 ≤ x1 ≤ 1.3, 0 ≤ y1 ≤ 1.3 and 0.7 ≤ x1 + y1 ≤ 1.3; 0.9 ≤ a1 ≤ 1.5, 0 ≤ b1 ≤ 0.5 and 0.9 ≤ a1 + b1 ≤ 1.5; 0 ≤ c1 ≤ 0.5; 3 ≤ z1 ≤ 5, wherein A comprises one or more of the elements Na, K, Mg, wherein Me comprises one or more of the elements Mn, Fe, Co, Ni, wherein M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce, wherein X comprises one or more of the elements S, Si, Cl, B, C, N, wherein Y comprises one or more of the elements O, F. [21] A battery cell according to claim 20, characterized by , that the specific surface area of ​​the lithium-containing phosphate with the olive stone structure is 5.0 m² 2 / g ~ 18.0 m 2 / g. [22] A battery cell according to any one of claims 17 to 19, characterized by, that the positive active material comprises a lithium-containing transition metal oxide, the composition of which is represented by the general formula II: Li x2 A y2 Ni a2 Co b2 Mn c2 M2 (1-a2-b2-c2) Y z2 Formula II where: 0 < x² ≤ 2.1, 0 ≤ y² ≤ 2.1 and 0.9 ≤ x² + y² ≤ 2.1; 0 ≤ a² ≤ 1, 0 ≤ b² ≤ 1, 0 ≤ c² < 1 and 0.1 ≤ a² + b² + c² ≤ 1; 1.8 ≤ z² ≤ 3.5, where A comprises one or more of the elements Na, K, Mg, where M comprises one or more of the elements B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce, where Y comprises one or more of the elements O, F. [23] A battery cell according to claim 22, characterized by , that the specific surface area of ​​the lithium-containing transition metal oxide is 0.1 m² 2 / g up to 2 m 2 / g, and wherein the mass fraction of the carbonate ester additive in the electrolyte solution is 1% ~ 5%, based on the total mass of the electrolyte solution. [24] A battery cell according to any one of claims 17 to 23, characterized by , that the positive active material also comprises an ion-conducting layer arranged on the surface of the lithium-containing phosphate, which contains carbon and iron elements, wherein, based on the total mass of the positive active material, the percentage mass fraction of the carbon element is 1 ~ 2%. [25] A battery cell according to claim 24, characterized by , that the ion-conducting layer comprises a fast ion conductor with a NASICON structure, as shown in Equation III, Li 3-b3 Fe 2-b3 M 2b3 (PO x3 )3 Formula III, where M2 in formula III comprises one or more of the elements Ti, Zr, Hf, Ge and Sn, optionally M2 being +4 valency, where 0 ≤ b3 ≤ 1, 3 ≤ x3 ≤ 5, 2 ≤ y3 ≤ 4. [26] A battery cell according to any one of claims 17 to 25, characterized by , that the positive membrane layer comprises a lithium supplement, wherein the lithium supplement is one or more of the following materials: ternary lithium supplement materials, lithium phosphate, lithium hydrogen phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium para-silicate, lithium para-manganate, lithium tartrate and lithium citrate. [27] A battery cell according to claim 26, characterized by , that the mass fraction of the lithium supplement is 0.1% to 10%, based on the total mass of the positive membrane layer. [28] A battery cell according to any one of claims 1 to 27, characterized by , that the negative electrode material includes graphite. [29] A battery cell according to claim 28, characterized by , that the graphite comprises composite graphite particles, wherein the composite graphite particles comprise main body particles and a coating arranged on the surface of the main body particles, wherein the main body particles comprise artificial graphite, wherein the coating comprises amorphous carbon and the composite graphite particles comprise secondary particles, wherein optionally the mass fraction of amorphous carbon in the coating of the composite graphite particles is 2% to 5%, based on the total mass of the composite graphite particles. [30] A battery cell according to any one of claims 1 to 29, characterized by that the negative electrode material meets at least one of the following conditions: (1) wherein the specific powder resistance of the negative electrode material is less than or equal to 0.04 Ω•cm, (2) wherein the negative electrode material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N 3 up to 1.8 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.75 g / cm³ 3 has. [31] A battery cell according to any one of claims 1 to 30, characterized by , that the negative electrode material also comprises a silicon-based material, wherein the silicon-based material comprises at least one of silicon, silicon oxide and silicon-carbon composites, wherein the mass fraction of the silicon element in the silicon-based material is 0.3% to 10%, optionally 1% to 6%, based on the total mass of the negative active material. [32] A battery cell according to any one of claims 1 to 31, characterized by , that the negative electrode material comprises a silicon-based material, wherein the mass fraction of the carbonate ester additive in the electrolyte solution is 3% to 10%. [33] A battery cell according to any one of claims 1 to 32, characterized by , that the negative membrane layer comprises a first negative membrane layer arranged on the surface of the negative current collector and a second negative membrane layer arranged on the side of the first negative membrane layer facing away from the negative current collector, wherein the second negative membrane layer comprises composite graphite particles, wherein optionally the negative electrode material in the first negative membrane layer comprises one or more of composite graphite particles and natural graphite. [34] A battery cell according to claim 33, characterized by , that the ratio of the thickness of the second negative active material layer to the thickness of the first negative active material layer is 3:7 to 7:

3. [35] A battery cell according to claim 33 or 34, characterized by, that the volume-averaged particle size Dv501 of the negative active material in the first negative active material layer is 9.5 µm ~ 18.5 µm, optionally 9.5 µm ~ 14.8 µm. [36] A battery cell according to any one of claims 33 to 35, characterized by , that the volume-averaged particle size Dv502 of the negative active material in the second negative active layer is 7.8 µm ~ 14.3 µm, optionally 7.8 µm ~ 12.8 µm. [37] A battery cell according to any one of claims 33 to 36, characterized by , that the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 7.8 µm ~ 10.8 µm, with the mass fraction of the carbonate ester additive in the electrolyte solution being 3% ~ 8%. [38] A battery cell according to claim 37, characterized by, that the mass fraction of the added vinyl carbonate in the electrolyte solution is 3% to 7% and the mass fraction of the added fluoroethylene carbonate is 0.5% to 2%. [39] A battery cell according to any one of claims 33 to 38, characterized by , that the volume-averaged particle size Dv502 of the negative electrode material in the second negative membrane layer is 10.8 µm ~ 14.8 µm, with the mass fraction of the added carbonate ester additive in the electrolyte solution being 2% ~ 7%. [40] A battery cell according to claim 39, characterized by , that in the electrolyte solution the mass fraction of the added vinyl carbonate is 2% to 6% and the mass fraction of the added fluoroethylene carbonate is 0.5% to 2.5%. [41] A battery cell according to any one of claims 1 to 40, characterized by , that the mass fraction of the chain-like carboxylic acid ester is 25.5% to 63.75%, based on the total mass of the electrolyte solution. [42] A battery cell according to any one of claims 1 to 41, characterized by , that the chain-like carboxylic acid ester has the general structural formula R1-COO-R2, wherein R1 and R2 each independently comprise at least one of C1-C5 alkyl and C1-C5 haloalkyl. [43] A battery cell according to any one of claims 1 to 42, characterized by that the chain-like carboxylic acid ester comprises one or more of ethyl butyrate, ethyl propionate, ethyl acetate, methyl acetate and methyl formate. [44] A battery cell according to any one of claims 1 to 43, characterized by that the solvent also contains carbonate ester solvent, wherein the mass fraction of the carbonate ester solvent, based on the total mass of the solvent of the electrolyte solution, is 17% - 76.5%, optionally 21.25% - 59.5%. [45] A battery cell according to claim 44, characterized bythat the carbonate ester solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate. [46] A battery cell according to claim 44 or 45, characterized by , that the carbonate ester solvent comprises ethylene carbonate, wherein the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester is 0.27:1 - 1.33:

1. [47] A battery cell according to claim 44 or 45, characterized by , that the electrolyte solution comprises lithium salts, wherein the carbonate ester solvents comprise ethylene carbonate, wherein the mass ratio between the lithium salts and ethylene carbonate is 0.29 - 0.

72. [48] ​​A battery cell according to any one of claims 1 to 47, characterized by , that the electrical conductivity of the electrolyte solution is 13 mS / cm - 20 mS / cm, optionally 15 mS / cm - 20 mS / cm. [49] A battery cell according to any one of claims 47 to 48, characterized bythat the lithium salt comprises one or more of the fluorosulfonylimide salt and lithium hexafluorophosphate, optionally comprising the fluorosulfonylimide salt one or more of the lithium difluorosulfonylimide and lithium trifluoromethylsulfonylimide. [50] A battery cell according to any one of claims 47 to 49, characterized by , that the lithium-containing electrolyte salt comprises lithium difluorosulfonylimide and lithium hexafluorophosphate, wherein the molar concentration of lithium difluorosulfonylimide in the electrolyte solution is 0.2 mol / L - 0.5 mol / L, and wherein the molar concentration of lithium hexafluorophosphate in the electrolyte solution is 0.5 mol / L - 1.0 mol / L. [51] A battery cell according to claim 50, characterized by , that the ratio of the molar concentration of lithium difluorosulfonylimide in the electrolyte solution to the molar concentration of lithium hexafluorophosphate in the electrolyte solution is (2-5):

10. [52] A battery cell according to any one of claims 1 to 51, characterized by , that the battery cell also comprises a separating membrane which includes a porous base membrane and a functional layer which is arranged on at least one side of the porous base membrane, wherein the thickness of the porous base membrane is ≤ 12 µm, or optionally less than or equal to 9 µm. [53] A battery cell according to claim 52, characterized by that the porosity of the porous base membrane in the separation membrane is 20% - 70%, optionally 35% - 60%. [54] A battery cell according to claim 52 or 53, characterized by, that the functional layer comprises a first functional layer arranged on the negative electrode side of the porous base membrane and a second functional layer arranged on the positive electrode side of the porous base membrane, wherein the first functional layer comprises first inorganic particles, wherein the second functional layer comprises composite particles, the composite particles comprising second inorganic particles and a non-fluorinated polymer, wherein the second inorganic particles in the composite particles adhere to the surface of the non-fluorinated polymer particles and / or are distributed within the interior of the non-fluorinated polymer particles. [55] A battery cell according to claim 54, characterized by that the non-fluorinated polymer particles comprise acrylate copolymers. [56] A battery cell according to any one of claims 1 to 55, characterized by, that the liquid supply coefficient of the battery cell is 2.2 g / Ah - 3.1 g / Ah. [57] A battery cell according to any one of claims 1 to 56, characterized by , that the fast charging time of the battery cell, charged from 10% SOC to 80% SOC, is 6 min to 15 min. [58] A battery unit comprising a battery cell according to any one of claims 1 to 57, wherein the battery unit comprises at least one of the following elements: a battery module, a battery pack or an energy storage battery. [59] An electrical device comprising a battery cell according to any one of claims 1 to 57.

Images