A battery cell, a battery unit and an electrical device

Abstract

A battery cell comprising a positive electrode plate and an electrolyte solution, wherein the positive electrode plate comprises a positive current collector and a positive active layer located on at least one surface of the positive current collector, wherein the positive active layer comprises a positive active material containing lithium phosphate, wherein the one-sided areal density of the positive active layer is 230 mg / 1540.25 mm² 2 ~ 400 mg / 1540.25 mm 2 amounts, wherein the electrolyte solution contains a solvent and a lithium-containing electrolyte salt, wherein the solvent comprises a chain-like carboxylic acid ester and an ethylene carbonate, wherein the lithium-containing electrolyte salt comprises one or more of lithium hexafluorophosphate and fluorine-containing sulfonylimide salts, wherein the mass ratio between the lithium-containing electrolyte salt and the ethylene carbonate is 0.29 to 0.72, where the conductivity of the electrolyte solution is 13 mS / cm to 20 mS / cm.

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 increasing market demands for both the range and energy efficiency of electrical appliances, the requirements for the energy density and fast-charging capability of battery cells are also rising. However, with current technologies, it is difficult to improve these properties simultaneously, which has become a pressing technical challenge in this field. Description of the invention

[0004] The present application is carried out taking into account the above-mentioned task and aims to provide a battery cell that has both a high energy density and good fast-charging capability.

[0005] A first aspect of the present application provides a battery cell comprising a positive electrode plate and an electrolyte solution. The positive electrode plate comprises a positive current collector and a positive active layer located on at least one surface of the positive current collector. The positive active layer comprises a positive active material containing lithium phosphate. The one-sided areal density of the positive active layer is 230 mg / 1540.25 mm². 2 ~ 400 mg / 1540.25 mm 2The electrolyte solution contains a solvent and a lithium-containing electrolyte salt, wherein the solvent comprises a chain-like carboxylic acid ester and an ethylene carbonate, and the lithium-containing electrolyte salt comprises one or more lithium hexafluorophosphate and fluorine-containing sulfonylimide salts, wherein the mass ratio between the lithium-containing electrolyte salt and the ethylene carbonate is 0.29 - 0.72, and wherein the conductivity of the electrolyte solution is 13 mS / cm - 20 mS / cm.

[0006] Ethylene carbonate and lithium ions in lithium-containing electrolyte salts readily form solvated structures in the electrolyte solution, thereby increasing the dissociation rate of lithium ions and anions. However, with increasing ethylene carbonate content, the viscosity of the electrolyte solution also increases, negatively impacting its conductivity. Chain-like carboxylic acid esters can improve the wettability between the electrolyte solution and the electrode plate, thereby increasing 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 improving the conductivity of the electrolyte solution.A positive electrode plate made of lithium-containing phosphate with a one-sided areal density within the aforementioned range exhibits both a high solid-phase lithium ion transport rate and a high loading of the positive active material. In combination with the aforementioned electrolyte solution, the battery cell has a tailored lithium ion dissociation rate, lithium ion liquid-phase transport rate, lithium ion liquid-solid transport rate, and lithium ion solid-phase transport rate. The mutual coordination of these individual steps achieves a balance between the fast-charging capability and energy density of the battery cell.

[0007] In one embodiment, the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester in the electrolyte solution is 0.26:1 - 1:1.

[0008] The mass ratio of ethylene carbonate to the aforementioned chain-like carboxylic acid ester 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 benefits the improvement of the fast-charging capability of the battery cell.

[0009] In one embodiment, the mass fraction of the chain-like carboxylic acid ester, based on the total mass of the electrolyte solution, is 25.5% - 63.75%.

[0010] 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 fast-charging capability and cycle stability of the battery cell.

[0011] In one embodiment, the chain-like carboxylic acid ester has the general structural formula R1-COO-R2, wherein R1 and R2 each independently comprise one or more of C1~C5 alkyl and C1-C5 haloalkyl.

[0012] 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.

[0013] In one embodiment, the mass fraction of ethylene carbonate, based on the total mass of the electrolyte solution, is 17% - 34%.

[0014] Electrolyte solutions with an ethylene carbonate content within the above-mentioned range exhibit good viscosity, dissociation rate and conductivity, which contributes to a comprehensive improvement in the fast-charging properties of the battery cell.

[0015] In one embodiment, the lithium-containing electrolyte salt comprises lithium hexafluorophosphate LiPF6.

[0016] In one embodiment, the lithium-containing electrolyte salt also comprises at least one of the fluorosulfonylimide salts; optionally, the fluorosulfonylimide salt comprises one or more lithium difluorosulfonylimide (LiFSI) and lithium trifluoromethylsulfonylimide (LiTFSI). Fluorosulfonylimide salts tend to decompose readily in electrolyte solutions, which advantageously increases the conductivity of the electrolyte solution. Furthermore, fluorosulfonylimide salts exhibit high chemical stability, do not decompose readily during cycle operation, reduce the formation of hydrogen fluoride during the battery cycle, and decrease the likelihood of side reactions at the negative electrode, thereby increasing the cycle stability of the battery cell.

[0017] In one embodiment, the lithium-containing electrolyte salt comprises lithium bisfluorosulfonylimide (LiFSI) and lithium hexafluorophosphate (LiPF6), wherein the mass ratio of lithium bisfluorosulfonylimide to lithium hexafluorophosphate (LiPF6) in the electrolyte solution (2-5) is 10.

[0018] Battery cells with a mass ratio of lithium bisfluorosulfonylimide and lithium hexafluorophosphate (LiPF6) in the electrolyte solution within the above-mentioned range can ensure both fast charging capability and battery cell safety.

[0019] In one embodiment, the battery cell also includes a negative electrode plate comprising a negative collector and a negative active layer arranged on at least one side of the negative current collector, wherein the negative active layer comprises a negative active material whose volume distribution of particle size Dv10 negativ3.5 µm - 7.5 µm, optionally 4.5 µm - 6.5 µm, where Dv99 negativ 25 µm - 35 µm.

[0020] The negative active material with Dv10 negativ and Dv99 negativ Within the aforementioned area, it contains a certain proportion of both small and large particles, which means that in the battery cell, the small particles increase the transfer rate of lithium ions and improve the fast charging capability, 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 fast charging capability and energy density to be achieved.

[0021] In one embodiment, the electrolyte solution also contains additives, wherein the additives comprise at least one of the following: carbonate ester additives, sulfur-containing additives, and lithium salt additives. The lithium salt additives comprise one or more of lithium difluorophosphate (LiPO₂F₂), lithium difluorooxaloborate (LiDFOB), lithium tetrafluoroborate (LiBF₄), and lithium diborate (LiBOB).

[0022] The additives mentioned above are all film-forming additives that can preferably form a film on the surface of the negative active layer in the electrolyte solution in front of the solvents and lithium-containing electrolyte salts, thus improving the electrochemical performance of the battery cell.

[0023] The SEI membrane components formed by carbonate ester additives consist mainly of organic components and exhibit excellent toughness, thus improving the cycle stability of the battery cell. SEI membrane components formed by sulfur-containing additives exhibit excellent thermal and chemical stability, compensating for the shortcomings of the organic components and improving the battery cell's storage performance at high temperatures. Lithium salt additives can address the problem of insufficient lithium ions at high charging speeds, improve the stability of the SEI layer, and simultaneously replenish lithium.

[0024] In one embodiment, the additives comprise at least two of the following additives: carbonate ester additives, sulfur-containing additives, and lithium salt additives.

[0025] The interaction of two or more components improves the overall performance of the battery cell during fast charging.

[0026] In one embodiment, the mass fraction of the additive in the electrolyte solution, based on the total mass of the electrolyte solution, is 1% to 10%, optionally 2% to 8%, and further optionally 3.5% to 8%.

[0027] In one embodiment, the carbonate ester additives comprise one or more of vinyl carbonate VC and fluoroethylene carbonate FEC.

[0028] In one embodiment, the sulfur-containing additive comprises one or more of the following substances: ethyl sulfate ester DTD, bis-ethyl sulfate ester 2-DTD, butyl sulfate ester BS, 1,3-propane sulfate ester PS, ethyl sulfate ester ES, methyl methane sulfate ester MMDS.

[0029] In one embodiment, the additive comprises vinyl carbonate VC, wherein the mass fraction of vinyl carbonate VC in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.5% to 9%, optionally 2% to 6%.

[0030] Chain-like carboxylic acid esters exhibit high activity, improve wettability between the electrolyte solution and the electrode plate, increase the conductivity of the electrolyte solution, and can simultaneously attack the solid-state electrolyte membrane (SEI membrane). Vinyl carbonate (VC) has a similar reduction potential to chain-like carboxylic acid esters, can inhibit the reactivity of chain-like carboxylic acid esters, and improve the cycle life of the battery cell.

[0031] In one embodiment, the additive comprises fluoroethylene carbonate (FEC), wherein the mass fraction of the 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%.

[0032] Excessive vinyl carbonate (VC) content can increase the battery's interfacial resistance and charge transfer resistance, negatively impacting its fast-charging capability. Fluoroethylene carbonate (FEC) can also form a membrane on the negative electrode surface at higher electrical potentials and exhibits low interfacial resistance and charge transfer resistance. However, the high-temperature stability of the SEI membrane formed by FEC is poor, adversely affecting the battery cell's stability in high-temperature environments. Adding both vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the electrolyte solution effectively balances the battery cell's fast-charging capability with its high-temperature stability.

[0033] In one embodiment, the electrolyte solution comprises vinyl carbonate and fluoroethylene carbonate, wherein the ratio of the total mass of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the mass of the chain-like carboxylic acid ester is 0.008 - 0.5.

[0034] The combination of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) reduces the erosion of the SEI membrane by chain-like carboxylic acid esters in the electrolyte solution, effectively ensuring both the fast charging capability and the storage stability of the battery cell.

[0035] In one embodiment, the electrical conductivity of the electrolyte solution is 14 mS / cm - 20 mS / cm, optionally 15 mS / cm - 20 mS / cm.

[0036] An electrolyte solution with an electrical conductivity within the above-mentioned range can better balance the fast charging capability and the cycle life of the battery cell.

[0037] In one embodiment, the one-sided areal density of the positive active layer is 280 mg / 1540.25 mm². 2 ~ 370 mg / 1540.25 mm 2 .

[0038] A positive active layer with a one-sided areal density within the above-mentioned area can more effectively balance the fast charging capability and energy density of the battery cell.

[0039] In one embodiment, the compaction density of the positive active layer at 100% SOC of the battery cell is 2.50 g / cm³. 3 ~ 2.80 g / cm³ 3 , optional 2.55 g / cm² 3 ~ 2.68 g / cm³ 3 .

[0040] In a battery cell with 100% SOC, the positive active layer can achieve a balance between the fast charging capability and the energy density of the battery cell with a density within the range mentioned above.

[0041] In one embodiment, the lithium-containing phosphate is a lithium-containing phosphate with an olive stone structure, comprising the components shown in 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.

[0042] Lithium-containing phosphates with olive stone structure, which contain the above-mentioned components, exhibit good structural stability, thereby reducing losses during fast charging and improving the cycle stability of the battery cell.

[0043] In one embodiment, the positive active material also comprises an ion-conducting layer arranged on the surface of the lithium-containing phosphate, which contains carbon elements, wherein, based on the total mass of the positive active material, the percentage mass fraction of the carbon element is 1 ~ 2%.

[0044] The aforementioned carbon element-containing ion-conducting layer can simultaneously improve the ion conductivity and electrical conductivity of the positive active material, optimize the solid-phase transfer rate of ions and electrons, and improve the energy density and fast-charging capability of the battery cell.

[0045] In one embodiment, the ion-conducting layer further comprises a fast ion conductor with a NASICON structure, as shown in Equation II. Li 3-b2 Fe 2-b2 M2 b2 (PO x2 ) y2 Formula II where in formula II M2 is selected from one or more of the elements Ti, Zr, Hf, Ge and Sn with a valency of +4, where 0 ≤ b2 ≤ 1, 3 ≤ x2 ≤ 5, 2 ≤ y2 ≤ 4.

[0046] 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 energy density and fast-charging capability of the corresponding battery cell.

[0047] In one embodiment, the fast ion conductor comprises one or more Li2FeTi(PO4) 33 , Li2FeZr(PO4)3, Li2FeSn(PO4)3.

[0048] In one embodiment, the positive active material has a powder compaction density of greater than or equal to 2.46 g / cm³ under a pressure of 30000 N. 3 , optional 2.46 g / cm² 3 - 2.8 g / cm³ 3 .

[0049] In one embodiment, the volume-averaged particle size of the positive active material satisfies the following conditions: 1 µm ≤ Dv50 positiv ≤ 2 µm, 0.4 µm ≤ Dv10 positiv ≤ 0.7 µm.

[0050] The aforementioned positive active material effectively improves the powder density and charge carrier conduction between the positive active materials through the particle size distribution, which benefits both the energy density and the fast-charging capability of the battery cell.

[0051] In one embodiment, the specific powder resistance R of the positive active material is ≤ 27.5 Ω•cm.

[0052] In one embodiment, the specific surface area S of the positive active material is 5 m². 2 / g ~ 18 m 2 / G.

[0053] The carbon structure in the positive active layer is of high relevance. The positive active material, with powder resistance and a specific surface area within the aforementioned range, exhibits both good ionic and electronic conductivity, which contributes to improving the fast-charging capability of the battery cell.

[0054] In one embodiment, the positive active layer comprises a lithium supplement, wherein the lithium supplement comprises at least one 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.

[0055] 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.

[0056] In one embodiment, the ternary lithium supplement material has the general formula as shown in Formula III, Li x3 A y3 Ni a3 Co b3 Mn c3 M3 (1-a3-b3-c3) Y z3 , Formula III, where 0 ≤ x3 ≤ 2.1, 0 ≤ y3 ≤ 2.1 and 0.9 ≤ x3 + y3 ≤ 2.1; 0 ≤ a3 ≤ 1, 0 ≤ b3 ≤ 1, 0 ≤ c3 ≤ 1 and 0.1 ≤ a3 + b3 + c3 ≤ 1; 1.8 ≤ z3 ≤ 3.5; A includes one or more of the elements Na, K, Mg; M includes 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 includes one or more of the elements O, F.

[0057] In one embodiment, the mass fraction of the added lithium supplement in the positive membrane layer is 0.1% to 10%.

[0058] In one embodiment, the positive electrode plate comprises a positive conductive layer arranged between the positive current collector and the positive active layer, wherein the thickness of the positive conductive layer is 0.5 µm ~ 2 µm; and / or the negative electrode plate comprises a negative conductive layer, wherein the negative conductive layer is arranged between the negative current collector and the negative active layer and the thickness of the negative conductive layer is 0.5 µm ~ 2 µm.

[0059] The arrangement of a positive and / or negative conductive layer contributes to increasing the electronic conductivity of the electrode plate of the battery cell and improves the energy density of the battery cell.

[0060] In one embodiment, the positive conductive layer comprises a conductivity agent and a first binder, while the negative conductive layer comprises a conductivity agent and a second binder, wherein the conductivity agent comprises one or more of the following: superconducting carbon, conductive graphite, acetylene black, carbon black, boron carbon black, carbon dots, carbon nanotubes, graphene and carbon nanofibers, wherein the conductivity agent optionally comprises superconducting carbon and carbon nanotubes, wherein the first binder comprises a fluorine-containing binder and the second binder comprises a water-soluble binder.

[0061] In one embodiment, based on the total mass of the positive electrically conductive layer, the mass fraction of the conductivity agent in the positive electrically conductive layer is 30% to 50% and the mass fraction of the first binder is 50% to 70%; and / or based on the total mass of the negative electrically conductive layer, the mass fraction of the conductivity agent in the negative electrically conductive layer is 20% to 40% and the mass fraction of the second binder is 60% to 80%.

[0062] In one embodiment, the one-sided areal density of the negative active layer is 104 mg / 1540.25 mm². 2 -180 mg / 1540.25 mm 2 , optional 125 mg / 1540.25 mm 2 -167 mg / 1540.25 mm 2 .

[0063] The negative active layer with a one-sided areal density within the above-mentioned area can interact with the positive active layer to enable a balance between the energy density and the fast-charging capability of the battery cell.

[0064] In one embodiment, the density of the negative active layer at 100% SOC of the battery cell is 1.15 g / cm³. 3 ~ 1.36 g / cm³ 3 , optional 1.25 g / cm² 3 ~ 1.36 g / cm³ 3 .

[0065] In one embodiment, the negative active material comprises graphite.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 fast-charging capability of the battery cell.

[0070] In one embodiment, the specific powder resistance of the negative active material is less than or equal to 0.04 Ω•cm.

[0071] In one embodiment, the negative active material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N. 3 up to 1.7 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.65 g / cm³ 3 .

[0072] The negative active 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, which helps to preserve the high fast-charging capability of the battery cell throughout the charging cycle.

[0073] In one embodiment, the negative active material further 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%.

[0074] The introduction of silicon-based materials contributes to improving the energy density of battery cells. Silicon-based materials within the aforementioned quality range can ensure both the energy density and the cycle stability of the battery cell.

[0075] In some embodiments, the specific charging capacity (per gram) of the negative active material is 350 mAh / g to 480 mAh / g.

[0076] The negative active material with a specific charging capacity (per gram) within the above-mentioned range contributes to increasing the energy density of the battery cell.

[0077] In one embodiment, the negative active layer comprises a first negative active material layer arranged on the surface of the negative current collector and a second negative active material layer arranged on the side of the first negative active material layer facing away from the negative current collector, wherein the second negative active material layer contains composite graphite particles.

[0078] In one embodiment, the first negative active material layer comprises one or more composite graphite particles and natural graphite.

[0079] The composite graphite particles are arranged near the electrolyte solution side to improve the fast charging capability of the battery cell while ensuring energy density.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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 fast-charging capability of the battery cell.

[0084] 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 less than or equal to 12 µm and optionally less than or equal to 9 µm.

[0085] In one embodiment, the porosity of the porous base membrane in the separating membrane is 20% - 70%, optionally 35% - 60%.

[0086] 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.

[0087] Inorganic particles can increase the heat resistance of the first and second functional layers and improve the fast-charging properties of the battery cell.

[0088] In one embodiment, the non-fluorinated polymer particles comprise acrylate copolymers.

[0089] In one embodiment, the liquid supply coefficient of the battery cell is 2.4 g / Ah - 3.1 g / Ah.

[0090] A fluid supply coefficient within the above-mentioned range can improve the cycle stability of the battery cell.

[0091] In one embodiment, the battery cell further comprises electrode terminals, wherein the electrode assembly includes an electrode tab that is directly welded to the electrode terminal.

[0092] In one embodiment, the time required to charge the battery cell from a state of charge (SOC) of 10% to a state of charge (SOC) of 80% at 30°C is 6 ~ 15 minutes.

[0093] The battery cell has good fast-charging capability and can meet the requirements for higher energy recharging efficiency for electrical devices.

[0094] In one embodiment, the battery cell has a wound structure, wherein the thickness of the positive current collector is less than or equal to 15 µm and the thickness of the negative current collector is less than or equal to 6 µm.

[0095] The positive current collector and / or the negative current collector have a smaller thickness, which further increases the energy density of the battery cell.

[0096] In one embodiment, the volume energy density of the battery cell is 400 Wh / L ~ 500 Wh / L.

[0097] This battery cell also has a high energy density and can meet the requirements for a longer range of electrical devices.

[0098] 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.

[0099] 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 a schematic representation of a battery cell of an embodiment of the present application. Fig. 2 shows an exploded view of the battery cell according to an embodiment of the present application, which is described in Fig. 1 is shown. Fig. Figure 3 is a schematic representation of the battery module according to an embodiment of the present application. Fig.Figure 4 is a schematic representation of the battery pack according to an embodiment of the present application. Fig. 5 is an exploded view of the in Fig. 4 battery pack shown according to an embodiment of the present application. Fig. Figure 6 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

[0100] 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.

[0101] 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.

[0102] Unless otherwise stated, all embodiments and optional embodiments of this application may be combined to form new technical solutions.

[0103] Unless otherwise stated, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0104] 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.

[0105] 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.

[0106] Unless otherwise specified, 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). Fast-charging technology aims to reduce the time required to charge the battery. This is achieved primarily by increasing the charging current and speed so that active ions can be rapidly inserted into and removed from the active material layer. High-energy-density batteries typically have a high areal density in the active material layer.However, a high areal density can impair the storage / release rate of active ions in the battery cell, thus reducing the battery cell's fast-charging capability. Therefore, fast-charging capability and energy density of a battery cell often represent seemingly contradictory requirements.

[0107] Based on this, the first aspect of this application provides a battery cell comprising a positive electrode plate and an electrolyte solution. The positive electrode plate comprises a positive current collector and a positive active layer located on at least one surface of the positive current collector. The positive active layer comprises a positive active material containing lithium phosphate. The one-sided areal density of the positive active layer is 230 mg / 1540.25 mm². 2 ~ 400 mg / 1540.25 mm 2The electrolyte solution contains a solvent and a lithium-containing electrolyte salt, wherein the solvent comprises a chain-like carboxylic acid ester and an ethylene carbonate, and the lithium-containing electrolyte salt comprises one or more lithium hexafluorophosphate and fluorine-containing sulfonylimide salts, wherein the mass ratio between the lithium-containing electrolyte salt and the ethylene carbonate is 0.29 - 0.72, and wherein the conductivity of the electrolyte solution is 13 mS / cm - 20 mS / cm.

[0108] In this application, “the one-sided areal density of the positive active layer” refers to the mass of the positive active layer per unit area on one side of the current collector.

[0109] In this application, the areal density of the positive active layer on one side can be tested using methods known in this field. For example, a cold-pressed, one-sided coated positive electrode plate (in the case of double-sided coated positive electrode plates, the positive active layer can first be wiped off one side) can be punched out into small, round discs with an area of ​​S1, the mass of which is weighed and recorded as M1. Subsequently, the positive membrane layer of the aforementioned weighed positive electrode plate is wiped off, and the mass of the positive current collector is weighed and recorded as M0. The areal density of the positive electrode plate on one side is then calculated as (M1-M0) / S1.

[0110] In some embodiments, the one-sided areal density of the positive active layer can optionally be 230 mg / 1540.25 mm². 2 , 240 mg / 1540.25 mm 2 , 250 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm2 , 270 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 290 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 , 310 mg / 1540.25 mm 2 , 325 mg / 1540.25 mm 2 , 340 mg / 1540.25 mm 2 , 350 mg / 1540.25 mm 2 , 360 mg / 1540.25 mm 2 , 375 mg / 1540.25 mm 2 , 400 mg / 1540.25 mm 2 or a range of values ​​between any two values.

[0111] Lithium phosphate is an active material with an olivine structure containing lithium ions and phosphate groups. The nature of this positive active material can be tested using any method known in this field. For example, analysis can be performed using phase analysis techniques such as X-ray diffraction (XRD) in combination with elemental analysis methods such as energy spectroscopy and XPS.

[0112] The type and quality of the solvents and lithium-containing electrolyte salts 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 35 µm to 270 µm.After completion of the analysis, a complete ion chromatogram of the individual organic substances is obtained. Based on the position of the peaks in the chromatogram, the corresponding organic substances are identified, and the percentage of each organic substance is calculated based on the peak area. For example, the concentration of inorganic substances in the electrolyte solution can be tested using an ion chromatograph (IC). For this purpose, a quantitative 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 of inorganic substances is then analyzed, and the corresponding types of inorganic substances are identified based on the peak position in the chromatogram.

[0113] In some embodiments, the mass ratio of lithium-containing electrolyte salt to ethylene carbonate can be 0.29, 0.31, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72 or a range between any two of these values.

[0114] 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 time of at least 10 seconds.

[0115] In some embodiments, the conductivity of the electrolyte solution can optionally be 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 any two of these values.

[0116] Ethylene carbonate and lithium ions in lithium-containing electrolyte salts readily form solvated structures in the electrolyte solution, thereby increasing the dissociation rate of lithium ions and anions. However, with increasing ethylene carbonate content, the viscosity of the electrolyte solution also increases, negatively impacting its conductivity. Chain-like carboxylic acid esters can improve the wettability between the electrolyte solution and the electrode plate, thereby increasing 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 improving the conductivity of the electrolyte solution.A positive electrode plate made of lithium-containing phosphate with a one-sided areal density within the aforementioned range exhibits both a high solid-phase lithium ion transport rate and a high loading of the positive active material. In combination with the aforementioned electrolyte solution, the battery cell has a tailored lithium ion dissociation rate, lithium ion liquid-phase transport rate, lithium ion liquid-solid transport rate, and lithium ion solid-phase transport rate. The mutual coordination of these individual steps achieves a balance between the fast-charging capability and energy density of the battery cell.

[0117] In some embodiments, the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester in the electrolyte solution is 0.26:1 to 1:1.

[0118] In some embodiments, the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester in the electrolyte solution can optionally be 0.26:1, 0.30:1, 0.36:1, 0.40:1, 0.46:1, 0.50:1, 0.56:1, 0.60:1, 0.66:1, 0.70:1, 0.76:1, 0.80:1, 0.86:1, 0.90:1, 0.96:1, 1:1 or a range between any two values.

[0119] The mass ratio of ethylene carbonate to the aforementioned chain-like carboxylic acid ester 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 benefits the improvement of the fast-charging capability of the battery cell.

[0120] 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.

[0121] In some embodiments, the mass fraction of the chain-like carboxylic acid ester, based on the total mass of the electrolyte solution, can optionally be 25.5%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 63.75% or a range between any two values.

[0122] 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 fast-charging capability and cycle stability of the battery cell.

[0123] In some embodiments, the chain-like carboxylic acid ester has the general structural formula R1-COO-R2, wherein R1 and R2 each independently comprise one or more of C1~C5 alkyl and C1~C5 haloalkyl.

[0124] “C1-C5 alkyl” refers to 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.

[0125] “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.

[0126] 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.

[0127] In some embodiments, the mass fraction of ethylene carbonate, based on the total mass of the electrolyte solution, is 17% - 34%.

[0128] In some embodiments, the mass fraction of ethylene carbonate, based on the total mass of the electrolyte solution, can optionally be 17%, 18%, 19%, 20%, 25%, 30%, 34% or a range between any two values.

[0129] Electrolyte solutions with an ethylene carbonate content within the above-mentioned range exhibit good viscosity, dissociation rate and conductivity, which contributes to a comprehensive improvement in the fast-charging properties of the battery cell.

[0130] In some embodiments, the lithium-containing electrolyte salt comprises lithium hexafluorophosphate LiPF6.

[0131] In some embodiments, the lithium-containing electrolyte salt also comprises at least one of the fluorosulfonylimide salts; optionally, the fluorosulfonylimide salt comprises one or more of lithium difluorosulfonylimide (LiFSI) and lithium trifluoromethylsulfonylimide (LiTFSI). Fluorosulfonylimide salts tend to decompose readily in electrolyte solutions, which increases the conductivity of the electrolyte solution. Furthermore, fluorosulfonylimide salts exhibit high chemical stability, do not decompose readily during cycle operation, reduce the formation of hydrogen fluoride during the battery cycle, and decrease the likelihood of side reactions at the negative electrode, thereby increasing the cycle stability of the battery cell.However, with increasing battery cell temperature, fluorosulfonylimide salts undergo significant decomposition below a certain temperature threshold, 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, its addition significantly reduces the risk of thermal instability, keeping the risk within a manageable range and enhancing battery safety.

[0132] In some embodiments, the lithium-containing electrolyte salt comprises lithium bisfluorosulfonylimide (LiFSI) and lithium hexafluorophosphate (LiPF6), wherein the mass ratio of lithium bisfluorosulfonylimide to lithium hexafluorophosphate (LiPF6) in the electrolyte solution (2-5) is 10.

[0133] In some embodiments, the mass ratio of lithium bisfluorosulfonylimide (LiFSI) and lithium hexafluorophosphate (LiPF6) in the electrolyte solution can be 2:10, 3:10, 4:10, 5:10, or a range between these two values. Battery cells with a mass ratio of lithium bisfluorosulfonylimide and lithium hexafluorophosphate (LiPF6) in the electrolyte solution within the aforementioned range can ensure both fast-charging capability and battery cell safety.

[0134] In some embodiments, the battery cell also includes a negative electrode plate comprising a negative collector and a negative active layer arranged on at least one side of the negative current collector, wherein the negative active layer comprises a negative active material whose volume distribution has a particle size Dv10 negativ 3.5 µm - 7.5 µm, optionally 4.5 µm - 6.5 µm, where Dv99 is negative 25 µm - 35 µm.

[0135] The volume distribution of particle size Dv10 negativ and Dv99 negativThe values ​​of the negative active material are generally known in this field and denote the particle size corresponding to the cumulative volume fraction of 10% or 99%. They can be measured using equipment and methods known in this field. For example, with reference to GB / T 19077-2016 "Laser diffraction method for determining particle size distribution", the measurement can be conveniently carried out using a laser particle size analyzer. The Mastersizer 3000 laser particle analyzer from the British company Malvern Instruments Ltd. can be used as a test instrument. The negative active material can either be freshly produced or obtained by scraping the powder from the negative active layer after disassembling a secondary cell.

[0136] In some embodiments, the volume distribution of the particle size Dv10 negativThe negative active material may optionally be 3.5 µm, 4.5 µm, 5.5 µm, 6.5 µm, 7.5 µm or a range between any two values.

[0137] In some embodiments, the volume distribution of the particle size Dv99 negativ The negative active material may optionally be 25 µm, 27 µm, 30 µm, 32 µm, 35 µm or a range between any two values.

[0138] The negative active materials with Dv10 negativ and Dv99 negativWithin the aforementioned area, the cells contain a certain proportion of both small and large particles, so that the battery cell can increase the transfer rate of lithium ions and improve fast charging capability through the small particles, and also improve the compaction density of the electrode plate of the battery cell through the size distribution of the particles, thereby increasing the energy density of the battery cell and achieving a balance between fast charging capability and energy density.

[0139] In some embodiments, the electrolyte solution also contains additives, wherein the additives comprise at least one of the following: carbonate ester additives, sulfur-containing additives, and lithium salt additives. The lithium salt additives comprise one or more of lithium difluorophosphate (LiPO₂F₂), lithium difluorooxaloborate (LiDFOB), lithium tetrafluoroborate (LiBF₄), and lithium diborate (LiBOB).

[0140] Additives are components present in small amounts in the electrolyte solution, typically comprising no more than 10% of the total mass. They are characterized by high precision and low dosage and can significantly improve battery performance within a specific range without altering the production process. The additive components can be tested using any established method in this field, such as liquid chromatography, UV spectrophotometry, or UV-Vis spectrophotometry. The composition of the electrolyte solution can also be determined using other techniques. For example, the concentration of inorganic substances in the electrolyte solution can be determined using an ion chromatograph (IC).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 of inorganic substances is examined, 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 dilute electrolyte solution for testing. Using a GC-MS 3100 gas chromatograph for organic compounds, the aforementioned dilute electrolyte solution is introduced into the instrument and subjected to a full qualitative scan analysis at a sampling point temperature of 250 °C. Scan range: 35 µm ~ 270 µm.After completion of the investigation, the total ion current chromatograms of the individual organic substances are obtained, whereby the corresponding types of organic substances are identified based on the peak positions in the chromatogram.

[0141] The additives mentioned above are all film-forming additives that can preferably form a film on the surface of the negative active layer in the electrolyte solution in front of the solvents and lithium-containing electrolyte salts, thus improving the electrochemical performance of the battery cell.

[0142] In some embodiments, the additives comprise at least two of the following additives: carbonate ester additives, sulfur-containing additives, and lithium salt additives.

[0143] The SEI membrane components formed by carbonate ester additives consist mainly of organic components and exhibit excellent toughness, thus improving the cycle stability of the battery cell. SEI membrane components formed by sulfur-containing additives exhibit excellent thermal and chemical stability, compensating for the shortcomings of the organic components and improving the battery cell's storage performance at high temperatures. Lithium salt additives can address the issue of insufficient lithium ions at high charging speeds, improve the stability of the SEI layer, and simultaneously replenish lithium. The interaction of two or more components enhances the overall performance of the battery cell during fast charging.

[0144] In some embodiments, the mass fraction of the additive in the electrolyte solution, based on the total mass of the electrolyte solution, is 1% to 10%, optionally 2% to 8%, and further optionally 3.5% to 8%.

[0145] In some embodiments, the mass fraction of the additive in the electrolyte solution, based on the total mass of the electrolyte solution, can optionally be 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 these two values.

[0146] The mass fraction of the additive in the electrolyte solution, relative to the total mass of the electrolyte solution, can be determined using any method known in this field. For example, the previously described method for testing the mass of the solvent and the lithium-containing electrolyte salt in the electrolyte solution can be used. It should be noted that the mass fraction of the additive in the electrolyte solution may be somewhat lower than the initial mass fraction due to the additive's consumption during the formation and cycling process and the formation of the corresponding components in the SEI membrane.

[0147] In some embodiments, the carbonate ester additives contain one or more of the following substances, including: vinyl carbonate VC, fluoroethylene carbonate FEC.

[0148] In some embodiments, the sulfur-containing additive comprises one or more of the following substances: ethyl sulfate ester DTD, bis-ethyl sulfate ester 2-DTD, butyl sulfate ester BS, 1,3-propane sulfate ester PS, ethyl sulfate ester ES, methyl methane sulfate ester MMDS.

[0149] In some embodiments, the additive comprises vinyl carbonate VC, wherein the mass fraction of vinyl carbonate VC in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.5% to 9%, optionally 2% to 6%.

[0150] In some embodiments, the mass fraction of vinyl carbonate VC in the electrolyte solution, based on the total mass of the electrolyte solution, is optionally 0.5%, 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% or a range between any two values.

[0151] 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, can inhibit their reactivity, and improve the cycle life of the battery cell.

[0152] In some embodiments, the additive comprises fluoroethylene carbonate (FEC), wherein the mass fraction of the 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%.

[0153] 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%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or a range between any two values.

[0154] Excessive vinyl carbonate (VC) content can increase the battery's interfacial resistance and charge transfer resistance, negatively impacting its fast-charging capability. Fluoroethylene carbonate (FEC) can also form a membrane on the negative electrode surface at higher electrical potentials and exhibits low interfacial resistance and charge transfer resistance. However, the high-temperature stability of the SEI membrane formed by FEC is poor, adversely affecting the battery cell's stability in high-temperature environments. Adding vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the electrolyte solution effectively balances the battery cell's fast-charging capability with its high-temperature stability.

[0155] In some embodiments, the electrolyte solution comprises vinyl carbonate and fluoroethylene carbonate, wherein the ratio of the total mass of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the mass of the chain-like carboxylic acid ester is 0.008 - 0.5.

[0156] In some embodiments, the ratio of the total mass of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) to the mass of the chain-like carboxylic acid ester in the electrolyte solution can optionally be 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5 or a range between any two values.

[0157] The combination of vinyl carbonate (VC) and fluoroethylene carbonate (FEC) reduces the erosion of the SEI membrane by chain-like carboxylic acid esters in the electrolyte solution, effectively ensuring both the fast charging capability and the storage stability of the battery cell.

[0158] In some embodiments, the electrical conductivity of the electrolyte solution is 14 mS / cm - 20 mS / cm, optionally 15 mS / cm - 20 mS / cm.

[0159] An electrolyte solution with an electrical conductivity within the above-mentioned range can better balance the fast charging capability and the cycle life of the battery cell.

[0160] In some embodiments, the one-sided areal density of the positive active layer is 280 mg / 1540.25 mm². 2 ~ 370 mg / 1540.25 mm 2 .

[0161] A positive active layer with a one-sided areal density within the above-mentioned area can more effectively balance the fast charging capability and energy density of the battery cell.

[0162] In some embodiments, the compaction density of the positive active layer at 100% SOC of the battery cell is 2.50 g / cm³. 3 ~ 2.80 g / cm³ 3 , optional 2.55 g / cm² 3~ 2.68 g / cm³ 3 .

[0163] In some embodiments, the compaction density of the positive active layer at 100% SOC of the battery cell can optionally be 2.50 g / cm³. 3 , 2.55 g / cm³ 3 , 2.60 g / cm³ 3 , 2.68 g / cm³ 3 , 2.70 g / cm³ 3 , 2.75 g / cm³ 3 , 2.80 g / cm³ 3 or a range of values ​​between any two values.

[0164] In this application, the density of the positive active layer at 100% state of charge (SOC) of the battery cell has the meaning generally known in this field and can be tested using methods known in this field. For example, the battery cell is charged to the cutoff voltage (e.g., 3.65 V) at a constant charging rate of 0.33 C, allowed to rest for 1 minute, and then further charged to the cutoff voltage at a constant charging rate of 0.1 C, at which point the battery cell is charged to 100% SOC. Subsequently, the positive electrode plate is removed, and the density of the positive active layer is determined. The density of the positive active layer is the areal density of the positive active layer measured after removal divided by the thickness of the positive active layer. The areal density of the positive active layer can be tested using the procedure described above.The thickness of the positive active layer is generally known in this field and can be tested using established methods, for example, with a micrometer (e.g., Mitutoyo 293-100 with an accuracy of 0.1 µm). It is understandable that the density of the positive active layer at 100% state of charge (SOC) of the battery cell differs from the target density of the battery cell and is influenced by actual operation, such that at 100% SOC the density of the positive active layer is often slightly lower than the target density of the battery cell.

[0165] In a battery cell with 100% SOC, the positive active layer can achieve a balance between the fast charging capability and the energy density of the battery cell with a density within the range mentioned above.

[0166] In some embodiments, the lithium-containing phosphate is a lithium-containing phosphate with an olive stone structure, comprising the components shown in Formula I: Li x1 Ay1Me 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.

[0167] 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..

[0168] Lithium-containing phosphates with olive stone structure, which contain the above-mentioned components, exhibit good structural stability, thereby reducing losses during fast charging and improving the cycle stability of the battery cell.

[0169] In some embodiments, the positive active material also comprises an ion-conducting layer arranged on the surface of the lithium-containing phosphate, which contains carbon elements, wherein, based on the total mass of the positive active material, the percentage mass fraction of the carbon element is 1 ~ 2%.

[0170] 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.

[0171] It should be noted that the ion-conducting layer can have either a single-layer or a multi-layer structure; that is, the ion-conducting component and the carbon-containing component in the ion-conducting layer can be either mixed or layered. It is understood that the ion-conducting layer exhibits a high ion transport rate.

[0172] The aforementioned carbon element-containing ion-conducting layer can simultaneously improve the ion conductivity and electrical conductivity of the positive active material, optimize the solid-phase transfer rate of ions and electrons, and improve the energy density and fast-charging capability of the battery cell.

[0173] In some embodiments, the ion-conducting layer also includes a fast ion conductor with a NASICON structure, as shown in Equation II. Li 3-b2 Fe 2-b2 M2 b2 (POx2 ) y2 Formula II where in formula II M2 is selected from one or more of the elements Ti, Zr, Hf, Ge and Sn with a valency of +4, where 0 ≤ b2 ≤ 1, 3 ≤ x2 ≤ 5, 2 ≤ y2 ≤ 4.

[0174] In some embodiments, 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; x2 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; y2 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.

[0175] 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.

[0176] Fast ion conductors, also known as superion conductors and solid electrolytes, are solids whose ionic conductivity approaches or even exceeds that of conductive liquids such as electrolyte solutions or molten salts. Fast ion conductors with a NASICON structure possess abundant 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. By applying a fast ion conductor with a NASICON structure to the surface of the lithium-containing phosphate, the lithium ion transfer rate during repeated lithium discharge and insertion at the positive electrode end can be significantly increased, thereby improving the ionic conductivity of the positive active material and optimizing the energy density and fast-charging capability of the corresponding battery cell.

[0177] In some embodiments, the fast ion conductor comprises one or more of the following compounds: Li2FeTi(PO4)3, Li2FeZr(PO4)3, Li2FeSn(PO4)3.

[0178] In some embodiments, the positive active material has a powder compaction density of greater than or equal to 2.46 g / cm³ under a pressure of 30000 N. 3 , optional 2.46 g / cm² 3 - 2.8 g / cm³ 3 .

[0179] In this application, the powder compaction density 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 24533-2009, a measurement can be carried out using an electronic pressure testing machine (e.g., an electronic pressure testing machine of type UTM7305). An exemplary measurement procedure is as follows: 1 g of powder of the positive active material is weighed and placed into a mold with a base area of ​​1.327 cm². 2 Given, a material was pressed with a pressure of 30000 N, 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 30000 N was recorded and calculated.

[0180] In some embodiments, the powder compaction density of the positive active material under a pressure of 30000 N can optionally be 2.46 g / cm³. 3 , 2.47 g / cm³ 3 , 2.48 g / cm³ 3 , 2.49 g / cm³ 3 , 2.5 g / cm³ 3 , 2.55 g / cm³ 3 , 2.6 g / cm³ 3 , 2.65 g / cm³ 3 , 2.7 g / cm³ 3 , 2.75 g / cm³ 3 , 2.8 g / cm³ 3 or a range of values ​​between any two values.

[0181] In some embodiments, the volume-averaged particle size of the positive active material satisfies the following conditions: 1 µm ≤ Dv50 positiv ≤ 2 µm, 0.4 µm ≤ Dv10 positiv ≤ 0.7 µm.

[0182] In some embodiments, the volume-averaged particle size Dv50 positiv The positive active material thickness can be either 1 µm, 1.1 µm, 1.2 µm, 1.3 µm, 1.4 µm, 1.5 µm, 1.6 µm, 1.7 µm, 1.8 µm, 1.9 µm, 2 µm, or any value between these two values. Dv10positiv can be 0.4 µm, 0.5 µm, 0.6 µm, 0.7 µm or a range between any two values.

[0183] For the volume-averaged particle size Dv50 positiv and Dv10 positiv The same test method applies to the positive active material as to the volume-averaged particle sizes of the aforementioned negative active material.

[0184] The aforementioned positive active material effectively improves the powder density and charge carrier conduction between the positive active materials through the particle size distribution, which benefits both the energy density and the fast-charging capability of the battery cell.

[0185] In some embodiments, the specific powder resistance R of the positive active material is ≤ 27.5 Ω·cm.

[0186] In this application, the specific powder resistance 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, a powder resistance meter (PRCD1100) can be used for analysis and testing in accordance with standard GB / T30835-2014.

[0187] In some embodiments, the powder resistivity R of the positive active material may optionally be 1 Ω cm, 2 Ω cm, 3 Ω cm, 4 Ω cm, 5 Ω cm, 6 Ω cm, 7 Ω cm, 8 Ω cm, 9 Ω cm, 10 Ω cm, 11 Ω cm, 12 Ω cm, 13 Ω cm, 14 Ω cm, 15 Ω cm, 16 Ω cm, 17 Ω cm, 18 Ω cm, 19 Ω cm, 20 Ω cm, 21 Ω cm, 22 Ω cm, 23 Ω cm, 24 Ω cm, 25 Ω cm, 26 Ω cm, 27 Ω·cm, 27.5 Ω·cm or a range of values ​​between either of these two values.

[0188] In some embodiments, the specific surface area S of the positive active material is 5 m². 2 / g ~ 18 m 2 / G.

[0189] 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.

[0190] In some embodiments, the specific surface area S of the positive active material can optionally be 5 m². 2 / g, 6 m 2 / g, 7 m 2 / g, 8 m 2 / g, 9 m 2 / g, 10 m 2 / g, 11 m 2 / g, 12 m 2 / g, 13 m 2 / g, 14 m 2 / g, 15 m 2 / g, 16 m 2 / g, 17 m 2 / g, 18 m 2 / g or a range of values ​​between either of the two.

[0191] The carbon structure in the positive active layer is of high relevance. The positive active material, with powder resistance and a specific surface area within the aforementioned range, exhibits both good ionic and electronic conductivity, which contributes to improving the fast-charging capability of the battery cell.

[0192] In some embodiments, the positive active layer comprises a lithium supplement, wherein the lithium supplement comprises at least one 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.

[0193] 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.

[0194] Ternary lithium supplements refer to lithium supplements containing one or more oxides of nickel, cobalt, and manganese. In some embodiments, the ternary lithium supplement has the general formula shown in Formula III. Li x3 A y3 Ni a3 Co b3 Mn c3 M3 (1-a3-b3-c3) Y z3 , Formula III, where 0 ≤ x3 ≤ 2.1, 0 ≤ y3 ≤ 2.1 and 0.9 ≤ x3 + y3 ≤ 2.1; 0 ≤ a3 ≤ 1, 0 ≤ b3 ≤ 1, 0 ≤ c3 ≤ 1 and 0.1 ≤ a3 + b3 + c3 ≤ 1; 1.8 ≤ z3 ≤ 3.5; A includes one or more of the elements Na, K, Mg; M includes 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 includes one or more of the elements O, F.

[0195] In some embodiments, x3 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 these two values, wherein y3 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 these two values. can be either of these two values, where x3+y3 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 these two values, where a3 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 these two values, where 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 these two values, where c3 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, and where a3+b3+c3 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, and where z3 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.

[0196] In some embodiments, the mass fraction of the added lithium supplement in the positive membrane layer is 0.1% to 10%.

[0197] In some embodiments, the mass fraction of the added lithium supplement in 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%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range between any two values.

[0198] 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.

[0199] In some embodiments, the positive electrode plate comprises a positive conductive layer arranged between the positive current collector and the positive active layer, wherein the thickness of the positive conductive layer is 0.5 µm ~ 2 µm; and / or the negative electrode plate comprises a negative conductive layer, wherein the negative conductive layer is arranged between the negative current collector and the negative active layer and the thickness of the negative conductive layer is 0.5 µm ~ 2 µm.

[0200] In some embodiments, the thickness of the positive or negative conductive layer can optionally be 0.5 µm, 0.6 µm, 0.7 µm, 0.8 µm, 0.9 µm, 1.0 µm, 1.1 µm, 1.2 µm, 1.3 µm, 1.4 µm, 1.5 µm, 1.6 µm, 1.7 µm, 1.8 µm, 1.9 µm, 2.0 µm or a range between any two values.

[0201] The arrangement of a positive and / or negative conductive layer contributes to improving the electronic conductivity of the electrode plate of the battery cell and improves the energy density of the battery cell.

[0202] In some embodiments, the positive conductive layer comprises a conductivity agent and a first binder, while the negative conductive layer comprises a conductivity agent and a second binder, wherein the conductivity agent comprises one or more of the following: superconducting carbon, conductive graphite, acetylene black, carbon black, boron carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, wherein the conductivity agent optionally comprises superconducting carbon and carbon nanotubes, wherein the first binder comprises a fluorine-containing binder and the second binder comprises a water-soluble binder.

[0203] In some embodiments, the term "fluorinated binder" refers to a binder containing the element fluorine, for example, comprising one or more of the following substances: polyvinylidene fluoride, polytetrafluoroethylene, a terpolymer copolymer of vinylidene fluoride, tetrafluoroethylene and propylene, a copolymer of vinylidene fluoride - hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylic acid ester resins, but not limited to.

[0204] In some embodiments, the term “water-soluble binder” refers to a binder that can be dispersed in an aqueous medium, for example, including, but not limited to, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resins, polyvinyl alcohol, sodium alginate, carboxymethyl chitosan, etc.

[0205] In some embodiments, based on the total mass of the positive electrically conductive layer, the mass fraction of the conductivity agent in the positive electrically conductive layer is 30% to 50% and the mass fraction of the first binder is 50% to 70%; and / or based on the total mass of the negative electrically conductive layer, the mass fraction of the conductivity agent in the negative electrically conductive layer is 20% to 40% and the mass fraction of the second binder is 60% to 80%.

[0206] In some embodiments, the mass fraction of the conductivity agent in the positive electrically conductive layer is 30% to 50% and the mass fraction of the first binder is 50% to 70%, based on the total mass of the positive electrically conductive layer.

[0207] In some embodiments, the mass fraction of the conductivity agent in the positive conductive layer can optionally be 30%, 35%, 40%, 45%, 50% or a range between either of these values, and the mass fraction of the first binder can optionally be 50%, 55%, 60%, 65%, 70% or a range between either of these values, relative to the total mass of the positive electrically conductive layer.

[0208] In some embodiments, the mass fraction of the conductivity agent in the negative electrically conductive layer is 20% to 40% and the mass fraction of the second binder is 60% to 80%, based on the total mass of the negative electrically conductive layer.

[0209] In some embodiments, the mass fraction of the conductivity agent in the negative electrically conductive layer is optionally 20%, 25%, 30%, 35%, 40% or a range between these two values, and the mass fraction of the first binder is optionally 60%, 65%, 70%, 75%, 80% or a range between these two values, based on the total mass of the negative electrically conductive layer.

[0210] In some embodiments, the one-sided areal density of the negative active layer is 104 mg / 1540.25 mm². 2 up to 180 mg / 1540.25 mm 2 ; optionally, it can deliver 125 mg / 1540.25 mm 2 up to 167 mg / 1540.25 mm 2 be.

[0211] The one-sided areal density of the negative active layer can be tested using a similar method to the one-sided areal density of the previously described positive active layer.

[0212] In some embodiments, the areal density of the negative active layer can optionally be 104 mg / 1540.25 mm². 2 , 110 mg / 1540.25 mm 2 , 115 mg / 1540.25 mm 2 , 120 mg / 1540.25 mm 2 , 125 mg / 1540.25 mm 2 , 130 mg / 1540.25 mm 2 , 140 mg / 1540.25 mm 2 , 150 mg / 1540.25 mm 2 , 160 mg / 1540.25 mm 2 , 167 mg / 1540.25 mm 2 , 170 mg / 1540.25 mm 2 , 180 mg / 1540.25 mm 2 or a range of values ​​between any two of these values.

[0213] The negative active layer with a one-sided areal density within the above-mentioned area can interact with the positive active layer to enable a balance between the energy density and the fast-charging capability of the battery cell.

[0214] In some embodiments, the density of the negative active layer at 100% SOC of the battery cell is 1.15 g / cm³.3 ~ 1.36 g / cm³ 3 , optional 1.25 g / cm² 3 ~ 1.36 g / cm³ 3 .

[0215] At 100% state of charge (SOC) of the battery cell, the density of the negative active layer can be tested based on the previously described density of the positive active layer at 100% SOC. It is understandable that the density of the negative active layer at 100% SOC will differ from the target density of the negative active layer after cold pressing. During charging and discharging, the insertion and removal of lithium ions into the negative active layer causes it to expand compared to its state after cold pressing. This results in a decrease in the density of the negative active layer at 100% SOC compared to its density after cold pressing.

[0216] In some embodiments, the compaction density of the negative active layer at 100% SOC of the battery cell can optionally be 1.15 g / cm³. 3 , 1.20 g / cm³ 3 , 1.25 g / cm³ 3 , 1.30 g / cm³ 3 , 1.35 g / cm³ 3 , 1.36 g / cm³ 3 or a range of values ​​between any two values.

[0217] In some embodiments, the negative active material comprises graphite.

[0218] 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.

[0219] 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.

[0220] In some embodiments, the composite graphite material also includes kinetic carbon material.

[0221] 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.

[0222] 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.

[0223] In some embodiments, the kinetic carbon material raw material comprises one or more of the following components: hard carbon, expanded graphite, and graphene.

[0224] 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".

[0225] In some embodiments, the layer spacing of the crystal face of the kinetic carbon material (002) d002 is ≥ 0.3358nm, optionally 0.3359 nm ~ 0.3366 nm.

[0226] 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 within the main body particles and / or the coating of the composite graphite material, this promotes the rapid entry and exit of active ions. This improves the transfer properties of active ions and electrons, thereby enhancing the fast-charging capabilities of the battery cell without a significant loss in energy density. Thus, both fast-charging capabilities and energy density are considered. 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.

[0227] 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.

[0228] 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 fast-charging capability of the battery cell.

[0229] In some embodiments, the specific powder resistance of the negative active material is less than or equal to 0.04 Ω•cm.

[0230] In some embodiments, the specific powder resistance of the negative active 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.

[0231] The specific powder resistance of the negative active material can be tested using any method known in this field. As an example, the previously described method for testing the powder resistance of the positive active material can be used.

[0232] In some embodiments, the negative active material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N. 3 up to 1.7 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.65 g / cm³ 3 .

[0233] The powder compaction density of the negative active material under a pressure of 20,000 N can be tested using a method known in this field. For example, instruments and methods known in this field can be used for measurement. For instance, 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. 2 Given, 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.

[0234] In some embodiments, the powder compaction density of the negative active 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 or a range of values ​​between any two of these values.

[0235] The negative active 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, which helps to preserve the high fast-charging capability of the battery cell throughout the charging cycle.

[0236] 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%.

[0237] 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 optionally be 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 any two values.

[0238] The introduction of silicon-based materials contributes to improving the energy density of battery cells. Silicon-based materials within the aforementioned quality range can ensure both the energy density and the cycle stability of the battery cell.

[0239] In some embodiments, the specific charging capacity (per gram) of the negative active material is 350 mAh / g to 480 mAh / g.

[0240] The specific charge capacity (per gram) of the negative active material can be tested using known test methods. For example, the test procedure for the first coulomb efficiency and the specific capacity of the first discharge according to Annex G of the national standard GB / T 24533-2019 can be used. The battery cell is disassembled to obtain the negative electrode plate, using a metal-lithium disk as the counter electrode, a polyethylene film as a separator, and the electrolyte solution from the battery cell as the electrolyte solution for the button cell. The CR2430 button cell is assembled in an argon-protected glove box.The finished button cell is left to rest for 12 hours, then discharged at 25 °C with a constant current of 0.05 C to 0.005 V, left to rest for 10 minutes, then discharged with a constant current of 50 µA to 0.005 V, left to rest for 10 minutes, and then discharged with a constant current of 10 µA to 0.005 V. It is then recharged with a constant current of 0.1 C to 2 V, and the charge capacity is recorded. The ratio of the charge capacity to the mass of the negative active material is the specific capacitance (per gram) of that material.

[0241] In some embodiments, the specific charge capacity (per gram) of the negative active material is 350 mAh / g, 360 mAh / g, 370 mAh / g, 380 mAh / g, 390 mAh / g, 400 mAh / g, 410 mAh / g, 420 mAh / g, 430 mAh / g, 440 mAh / g, 450 mAh / g, 460 mAh / g, 470 mAh / g, 480 mAh / g or a range of values ​​between any two of these.

[0242] The negative active material with a specific charging capacity (per gram) within the above-mentioned range contributes to increasing the energy density of the battery cell.

[0243] In some embodiments, the negative active layer comprises a first negative active material layer arranged on the surface of the negative current collector and a second negative active material layer arranged on the side of the first negative active material layer facing away from the negative current collector, wherein the second negative active material layer contains composite graphite particles.

[0244] In some embodiments, the first negative active material layer comprises one or more composite graphite particles and natural graphite.

[0245] The composite graphite particles are arranged near the electrolyte solution side to improve the fast charging capability of the battery cell while also improving the energy density.

[0246] 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.

[0247] 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 optionally be 3:7, 4:7, 5:7, 6:7, 1:1, 2:1, 7:3 or a range of values ​​between any two of these.

[0248] 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 ~ 18.5 µm, optionally 9.5 µm ~ 14.8 µm.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] 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.

[0253] 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 fast-charging capability of the battery cell.

[0254] 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 less than or equal to 12 µm and may optionally be less than or equal to 9 µm.

[0255] 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.

[0256] In some embodiments, the porosity of the porous base membrane in the separating membrane is 20% - 70%, optionally 35% - 60%.

[0257] In some embodiments, the porosity of the porous base membrane in the separating membrane can optionally be 20%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or a range between any two values.

[0258] 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.

[0259] In some embodiments, the inorganic particles comprise one or more of silicon oxide, aluminum oxide, borosilicate, barium sulfate, calcium oxide, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide and tin oxide.

[0260] Inorganic particles can increase the heat resistance of the first and second functional layers and improve the fast-charging properties of the battery cell.

[0261] In some embodiments, the non-fluorinated polymer particles comprise acrylate copolymers.

[0262] In some embodiments, the liquid supply coefficient of the battery cell is 2.4 g / Ah - 3.1 g / Ah.

[0263] 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.

[0264] In some embodiments, the liquid supply coefficient of the battery cell can optionally be 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.

[0265] A fluid supply coefficient within the above-mentioned range can improve the cycle stability of the battery cell.

[0266] In some embodiments, the battery cell also includes electrode terminals, wherein the electrode assembly includes an electrode tab that is directly welded to the electrode terminal.

[0267] In some embodiments, the time required for the battery cell to be charged from a state of charge (SOC) of 10% to a state of charge (SOC) of 80% at 30°C is 6 ~ 15 minutes.

[0268] The time required to charge a battery cell from a state of charge (SOC) of 10% to a state of charge (SOC) of 80% at 30°C can be determined by any method known in this field. As an example, at a temperature of 30 °C, a battery with a state of charge (SOC) of 10% is charged with a constant current of 5.0 C from 10% SOC to 15% SOC, with a constant current of 5.0 C from 15% SOC to 20% SOC, with a constant current of 5.0 C from 20% SOC to 25% SOC, with a constant current of 5.0 C from 25% SOC to 30% SOC, with a constant current of 5.0 C from 30% SOC to 35% SOC, with a constant current of 5.0 C from 35% SOC to 40% SOC, with a constant current of 4.6 C from 40% SOC to 45% SOC, with a constant current of 4.3 C from 45% SOC to 50% SOC, and with a constant current of 4.0 C Charged from 50% SOC to 55% SOC, with 3,Charged at a constant current of 7C from 55% SOC to 60% SOC, at a constant current of 3.4C from 60% SOC to 65% SOC, at a constant current of 3.1C from 65% SOC to 70% SOC, at a constant current of 2.9C from 70% SOC to 75% SOC, and at a constant current of 2.7C from 75% SOC to 80% SOC, with the total charging time being recorded.

[0269] In some embodiments, the time required to charge the battery cell from a state of charge (SOC) of 10% to a state of charge (SOC) of 80% at 30°C can optionally be 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.

[0270] The battery cell has good fast-charging capability and meets the requirements for higher energy recharging efficiency for electrical devices.

[0271] In some embodiments, the battery cell has a wound structure, wherein the thickness of the positive current collector is less than or equal to 15 µm and the thickness of the negative current collector is less than or equal to 6 µm.

[0272] The material of the positive and / or negative current collector is not subject to any special restrictions, as long as it does not cause any chemical changes in the battery cell and is conductive. The current collector comprises metal foils with a purity level of at least 95%, for example, at least one copper foil, aluminum foil, stainless steel foil, titanium foil, nickel foil, or an alloy foil made of at least two main metals, for example, an alloy foil made of at least two of the main elements copper, aluminum, nickel, titanium, and iron. Additionally, copper, aluminum-cadmium alloys, iron, or stainless steel with a surface treatment of carbon, nickel, titanium, silver, copper, etc., may be used.Furthermore, the bonding force with the negative active material can be enhanced by the formation of microscopically small irregularities on the surface, and it can be used in various forms such as membranes, plates, films, nets, porous bodies, foams, nonwovens, etc.

[0273] In some embodiments, the thickness of the positive current collector can optionally be 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm, 13 µm, 14 µm, 15 µm or a range between any two of these values.

[0274] In some embodiments, the thickness of the negative current collector can optionally be 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm or a range between any two of these values.

[0275] The positive current collector and / or the negative current collector have a smaller thickness, which further increases the energy density of the battery cell.

[0276] In some embodiments, the volume energy density of the battery cell is 400 Wh / L ~ 500 Wh / L.

[0277] In some embodiments, the volume energy density of the battery cell can optionally be 400 Wh / L, 410 Wh / L, 420 Wh / L, 430 Wh / L, 440 Wh / L, 450 Wh / L, 460 Wh / L, 470 Wh / L, 480 Wh / L, 490 Wh / L, 500 Wh / L or a range between any two of these values.

[0278] The volume energy density of the battery cell can be tested using a method known in this field. For example, the battery cell is charged at 25 °C with a constant current of 0.33 C to 3.65 V, then charged with a constant voltage to 0.05 C, discharged with a constant current of 0.33 C to 2.0 V, and the discharge capacity A0 (unit Ah) is recorded at this time. The length, width, and height of the battery cell are measured with calipers (usually calculated from the dimensions of the battery casing, excluding the height of the electrode terminals and the insulating film outside the casing), and the volume of the battery cell V0 is calculated in L. The volume energy density VED of the battery cell = (A0 × discharge platform voltage) / V0 in Wh / L.

[0279] This battery cell also has a high energy density and can meet the requirements for a longer range of electrical devices.

[0280] 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.

[0281] 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.

[0282] 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. 1 a square battery cell 5 as an example.

[0283] In some embodiments, the outer packaging can be designed according to the Fig.2. 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.

[0284] The Fig. Figure 3 shows an example of a battery module 4. As in the Fig. As shown in Figure 3, 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.

[0285] Optionally, the battery module 4 can also include a housing with a receiving space in which several battery cells 5 are housed.

[0286] 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. 4 and Fig. Figure 5 shows an example of a battery pack 1. As can be seen from the Fig. 4 and Fig. As can be seen in Figure 5, 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.

[0287] 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.

[0288] Furthermore, the third aspect of the present application provides an electrical device comprising the battery cell provided in the first aspect of the present application. 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.

[0289] Depending on the intended use, the electrical device in question can be a battery cell, battery module or battery pack.

[0290] The Fig.Figure 6 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.

[0291] 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

[0292] To clarify the technical problems, solutions, and advantages of this application, the following section provides further explanations 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.

[0293] 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

[0294] The positive active material lithium iron phosphate, the binder polyvinylidene fluoride, and the conductivity agent acetylene black are mixed in a ratio of 97:2:1. The solvent N-methylpyrrolidone (NMP) is then added and stirred to form a positive paste. The powder density of the positive active material is 2.53 g / cm³. 3 , the volume-averaged particle size Dv50 positiv of the positive active material 1.6 µm and Dv10 positiv 0.64 µm.

[0295] The positive conductive layer is formed by uniformly mixing conductive carbon SP, the binder polyvinylidene fluoride (PVDF) and the solvent N-methylpyrrolidone NMP, and then applying this mixture to the surface of the current collector with a thickness of 1 µm.

[0296] The positive conductive paste is applied evenly to the positive aluminum foil of the current collector, which has a thickness of 13 µm. After drying, the positive conductive layer is obtained. Subsequently, the positive conductive paste is applied evenly to this layer, dried, and cold-pressed to form the positive electrode plate. The areal density of the positive active layer of the electrode plate is 300 mg / 1540.25 mm². 2The battery is charged to 100% state of charge (SOC) at a charging rate of 0.33 C. The density of the positive electrode plate is 2.63 g / cm³. 3 . Production of the negative electrode plate

[0297] The negative active material, graphite, the conductivity agent acetylene carbon black, the binder styrene-butadiene rubber, and the thickener sodium carboxymethylcellulose are mixed in a mass ratio of 96:1:2:1. Deionized water is then added as a solvent and stirred to form a negative paste. This paste is applied evenly to the copper foil of the negative current collector, dried, and cold-pressed to create the negative electrode plate, which has a thickness of 4.5 µm. The areal density of the negative active layer of the negative electrode plate is 138 mg / 1540.25 mm². 2The battery is charged to 100% SOC at a charging rate of 0.33 C, with a density of 1.26 g / cm³ for the negative electrode plate. 3 and the volume distribution of the particle size Dv50 of the negative active materials is 10.5 µm. Preparation of the electrolyte solution

[0298] 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 thoroughly and uniformly mixed in a mass ratio of 35:15:50 to obtain an electrolyte solution. Lithium hexafluorophosphate (LiPF6) and lithium difluorosulfonylimide (LiFSI) are slowly added as lithium salts and stirred thoroughly until completely dissolved. After returning to room temperature, the additives vinyl carbonate (VC) at 3.5% by mass, fluoroethyl carbonate (FEC) at 1% by mass, 1,3-propylenesulfonic acid lactone (PS) at 0.5% by mass, ethylene sulfite (DTD) at 0.5% by mass, and lithium difluorophosphate (LiPO2F2) at 0.5% by mass are successively added and thoroughly and uniformly mixed to obtain the electrolyte solution.Based on the total mass of the electrolyte solution, the mass fraction of lithium hexafluorophosphate (LiPF6) is 10.5% and the mass fraction of lithium difluorosulfonylimide (LiFSI) is 4.5%. The conductivity of the electrolyte solution is 15.4 mS / cm. Production of the separation membrane

[0299] The separation membrane comprises a base membrane consisting of a 7 µm thick polyethylene membrane layer with a porosity of 42%. Battery cell manufacturing

[0300] 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.

[0301] The manufacturing processes in embodiments 2-12 are essentially identical to those in embodiment 1, with the difference that some parameters of the battery cell have been adapted, as shown in Table 1. Example 13

[0302] The manufacturing process for the battery in embodiment 13 is essentially identical to that in embodiment 1, with the difference that the negative electrode plate in embodiment 13 is double-coated. The method for manufacturing the negative electrode plate is as follows: The negative active material, namely first graphite, the conductivity agent acetylene black, the binder styrene-butadiene rubber and the thickening agent sodium carboxymethylcellulose, are mixed in a mass ratio of 96:0.5:2.5:1, and then deionized water is added as a solvent and this is stirred evenly to produce the first negative paste mass.

[0303] The negative active material, second graphite, the conductivity agent acetylene black, the binder styrene-butadiene rubber and the thickening agent sodium carboxymethylcellulose are mixed in a mass ratio of 96:0.5:2.5:1, and then deionized water is added as the solvent and this is stirred evenly to form the second negative paste mass.

[0304] The first negative paste is applied evenly to the negative conductive layer of the negative current collector copper foil and dried. After drying, the second negative paste is applied to the surface of the first, dried, and cold-pressed to form the negative electrode plate. The negative electrode plate comprises the negative current collector and the negative conductive layer and negative active material layer arranged sequentially on the negative current collector. The negative active material layer comprises the first negative active layer and the second negative active layer, arranged sequentially on the negative conductive layer.

[0305] The coating mass on one side of the negative electrode plate is 138 mg / mm². 2, based on the total mass of the negative active material layer, where the compaction density of the positive electrode plate is 1.25 g / cm³ 3 This is the value when the battery is charged to 100% SOC at a charging rate of 0.33 C. Based on the total mass of the first and second graphite in the negative active material layer, the mass fraction of the first and second graphite is 50% and 50%, respectively.

[0306] The manufacturing processes in comparative examples 1 to 6 are essentially identical to that in embodiment 1, with the difference that some parameters of the battery cell have been adapted. Test procedure (1) The test steps for the time T required to charge a battery cell from 10% SOC to 80% SOC at 30°C are as follows: At an ambient temperature of 30 °C, the battery is charged from a state of 10% SOC; With a constant current of 5.0 C, it is charged from 10% SOC to 15% SOC; With a constant current of 5.0 C, it is charged from 15% SOC to 20% SOC; With a constant current of 5.0 C, it is charged from 20% SOC to 25% SOC; With a constant current of 5.0 C, it will charge from 25% SOC to 30% SOC; With a constant current of 5.0 C, it will charge from 30% SOC to 35% SOC; With a constant current of 5.0 C, it will charge from 35% SOC to 40% SOC; With a constant current of 4.6 C, it is charged from 40% SOC to 45% SOC; With a constant current of 4.3C, it is charged from 45% SOC to 50% SOC; With a constant current of 4.0C, it is charged from 50% SOC to 55% SOC; With a constant current of 3.7C, it is charged from 55% SOC to 60% SOC; With a constant current of 3.4C, it is charged from 60% SOC to 65% SOC; With a constant current of 3.1C, it is charged from 65% SOC to 70% SOC; With a constant current of 2.9C, it is charged from 70% SOC to 75% SOC; With a constant current of 2.7C, it is charged from 75% SOC to 80% SOC.

[0307] The total charging time is recorded. Times vary depending on the specific implementation and can be adjusted by fine-tuning the charging speed. (2) Number of cycles for 60 °C cycles down to 80% SOH

[0308] 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, then discharged at a rate of 1C to 2.5 V, and left to rest for another 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 of the DC internal resistance DCR of the battery cell:

[0309] Reference is made to the method in GB / T 31467 “Test specifications for the performance of high-performance lithium-ion traction batteries for HEVs”.

[0310] For example, the battery cell is charged at room temperature with a constant current of 0.33 C to 3.65 V, left to rest for 1 minute, then charged with a constant current of 0.1 C to 3.65 V, left to rest for 30 minutes, discharged with a constant current of 0.33 C to 2.0 V, the discharge capacity A0 (in Ah) is recorded, and then charged with a constant current of 0.33 C to 0.5A0 in Ah to set the SOC to 50%.

[0311] The battery cell is stored at -20 °C for 2 hours and then discharged for 10 seconds at a constant current of 4C. During this process, ΔU Entladung and ΔI Entladung The discharge DCR data for the lithium-ion battery were recorded. The discharge DCR data was calculated using the following formula: R Entladung = ΔU Entladung / ΔI Entladung , where ΔU Entladung the voltage change within the first 10 seconds of discharge and ΔI EntladungThe current value is defined as the current value within the first 10 seconds of discharge. The parameters of the respective embodiments and comparative examples are partly listed in Table 1, where the values ​​refer to mass fractions and the units for the single-sided coating mass of the positive and negative electrodes are mg / 1540.25 mm². 2 are.

[0312] In embodiment 1, the density of the positive active layer in a battery cell with 100% SOC is 2.63 g / cm³. 3 ; where the density of the negative active layer in a battery cell with 100% SOC is 1.26 g / cm³ 3 amounts.

[0313] The test results for the respective embodiments and comparison examples are listed in Tables 2 and 3. Tables 2 Volume energy density Wh / L Charging time T (min) at 10% to 80% SOC Example 1 410 9,8 Example 2 398 8,4 Example 3 403 9,1 Example 4 418 12,5 Example 5 423 13,7 Example 6 410 11,6 Example 7 410 9,1 Example 8 410 10,6 Example 9 410 10,3 Example 10 410 10,8 Example 11 410 9,6 Example 12 410 9,9 Example 13 410 9,4 Comparative example 1 382 7,1 Comparative example 2 427 15,2 Comparative example 3 410 11,8 Comparative example 4 410 12,4 Comparative example 5 410 16,8 Comparison example 6 410 10,7 Table 3 -20 °C discharge DCRmΩ Number of cycles for 60 °C cycles up to 80% SOH Example 1 4,47 1194 Example 6 4,71 1162 Example 7 4,25 1022 Test results

[0314] A comparison between the embodiments of this application and the comparative examples shows that the positive active layer comprises a positive active material, wherein the positive active material contains lithium phosphate and the one-sided areal density of the positive active layer is 230 mg / 1540.25 mm². 2 up to 400 mg / 1540.25 mm 2The electrolyte solution contains a solvent and a lithium-containing electrolyte salt, wherein the solvent comprises a chain-like carboxylic acid ester and a carbonate ester, and the lithium-containing electrolyte salt comprises one or more lithium hexafluorophosphate and fluorine-containing sulfonylimide salts, wherein in the battery cell the mass ratio of the lithium-containing electrolyte salt to the ethylene carbonate is 0.29 to 0.72, wherein the conductivity of the electrolyte solution is 13 mS / cm to 20 mS / cm, thus taking into account both the energy density and the fast-charging capability of the battery cell, thereby achieving a comprehensive improvement in battery performance.

[0315] A comparison of embodiments 1, 6 and 7 shows that the battery cell in which the mass fraction of chain-like carboxylic acid esters is 25.5% to 63.75%, based on the total mass of the electrolyte solution, enables a further improvement in the cycle stability and overall performance of the battery cell.

[0316] 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 non-patent literature

[0000] GB / T 24533-2009 [0179, 0233] Standard GB / T30835-2014

[0186]

Claims

[1] A battery cell comprising a positive electrode plate and an electrolyte solution, wherein the positive electrode plate comprises a positive current collector and a positive active layer located on at least one surface of the positive current collector, wherein the positive active layer comprises a positive active material containing lithium phosphate, wherein the one-sided areal density of the positive active layer is 230 mg / 1540.25 mm² 2 ~ 400 mg / 1540.25 mm 2 amounts, wherein the electrolyte solution contains a solvent and a lithium-containing electrolyte salt, wherein the solvent comprises a chain-like carboxylic acid ester and an ethylene carbonate, wherein the lithium-containing electrolyte salt comprises one or more of lithium hexafluorophosphate and fluorine-containing sulfonylimide salts, wherein the mass ratio between the lithium-containing electrolyte salt and the ethylene carbonate is 0.29 to 0.72, where the conductivity of the electrolyte solution is 13 mS / cm to 20 mS / cm. [2] A battery cell according to claim 1, characterized by , that the mass ratio of ethylene carbonate to the chain-like carboxylic acid ester in the electrolyte solution is 0.26:1 to 1:

1. [3] A battery cell according to claim 1 or 2, characterized by , that the mass fraction of the chain-like carboxylic acid ester, based on the total mass of the electrolyte solution, is 25.5% to 63.75%. [4] A battery cell according to any one of claims 1 to 3, characterized by , that the chain-like carboxylic acid ester has the general structural formula R1-COO-R2, where R1 and R2 each independently comprise one or more of C1~C5 alkyl and C1~C5 haloalkyl. [5] A battery cell according to any one of claims 1 to 4, 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. [6] A battery cell according to any one of claims 1 to 5, characterized by , that the mass fraction of ethylene carbonate, based on the total mass of the electrolyte solution, is 17% - 34%. [7] A battery cell according to any one of claims 1 to 6, characterized by , that the lithium-containing electrolyte salt includes lithium hexafluorophosphate. [8] A battery cell according to claim 7, characterized by that the lithium-containing electrolyte salt further comprises at least one of the fluorosulfonylimide salts, optionally the fluorosulfonylimide salt comprises one or more of lithium difluorosulfonylimide and lithium trifluoromethylsulfonylimide. [9] A battery cell according to any one of claims 1 to 8, characterized by , that the lithium-containing electrolyte salt comprises lithium bisfluorosulfonylimide and lithium hexafluorophosphate, wherein the mass ratio of lithium bisfluorosulfonylimide to lithium hexafluorophosphate in the electrolyte solution is (2-5):

10. [10] A battery cell according to any one of claims 1 to 9, characterized by , that the battery cell further comprises a negative electrode plate which includes a negative collector and a negative active layer which is arranged on at least one side of the negative current collector, wherein the negative active layer comprises a negative active material whose volume distribution of particle size Dv10 negativ 3.5 µm - 7.5 µm, optionally 4.5 µm - 6.5 µm, where Dv99 negativ 25 µm - 35 µm. [11] A battery cell according to any one of claims 1 to 10, characterized by , that the electrolyte solution further contains additives comprising at least one of the following additives: carbonate ester additives, sulfur-containing additives and lithium salt additives, wherein the lithium salt additives comprise one or more of lithium difluorophosphate, lithium difluorooxaloborate, lithium tetrafluoroborate, lithium diborate. [12] A battery cell according to any one of claims 1 to 10, characterized by that the additives include at least two of the following additives: carbonate ester additives, sulfur-containing additives and lithium salt additives. [13] A battery cell according to claim 11 or 12, characterized by , that the mass fraction of the additive in the electrolyte solution, based on the total mass of the electrolyte solution, is 1% to 10%, optionally 2% to 8% and further optionally 3.5% to 8%. [14] A battery cell according to claim 11 or 12, 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. [15] A battery cell according to any one of claims 11 to 14, characterized bythat the sulfur-containing additive comprises one or more of the following substances: ethyl sulfate ester, bis-ethyl sulfate ester, butyl sulfate ester, 1,3-propane sulfate ester, ethyl sulfate ester, methylmethane sulfate ester. [16] A battery cell according to any one of claims 11 to 15, characterized by that the additive comprises vinyl carbonate, wherein the mass fraction of vinyl carbonate in the electrolyte solution, based on the total mass of the electrolyte solution, is 0.5% to 9%, optionally 2% to 6%. [17] A battery cell according to any one of claims 11 to 15, characterized by , that the additive comprises fluoroethylene carbonate, wherein the mass fraction of the 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%. [18] A battery cell according to any one of claims 1 to 17, characterized by, that the electrolyte solution comprises vinyl carbonate and fluoroethylene carbonate, wherein the ratio of the total mass of vinyl carbonate and fluoroethylene carbonate to the mass of the chain-like carboxylic acid ester is 0.008 - 0.

5. [19] A battery cell according to any one of claims 1 to 18, characterized by , that the electrical conductivity of the electrolyte solution is 14 mS / cm - 20 mS / cm, optionally 15 mS / cm - 20 mS / cm. [20] A battery cell according to any one of claims 1 to 19, characterized by , that the one-sided areal density of the positive active layer is 280 mg / 1540.25 mm² 2 - 370 mg / 1540.25 mm 2 amounts. [21] A battery cell according to any one of claims 1 to 20, characterized by , that the density of the positive active layer at 100% SOC of the battery cell is 2.50 g / cm³ 3 ~ 2.80 g / cm³ 3 , optional 2.55 g / cm² 3 ~ 2.68 g / cm³ 3 amounts. [22] A battery cell according to any one of claims 1 to 21, characterized by , that the lithium-containing phosphate is a lithium-containing phosphate with an olive stone structure, comprising the components shown in 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. [23] A battery cell according to claim 22, 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 elements, wherein the percentage mass fraction of the carbon element, based on the total mass of the positive active material, is 1 ~ 2%. [24] A battery cell according to claim 23, characterized by , that the ion-conducting layer further comprises a fast ion conductor with a NASICON structure, as shown in Equation II, Li 3-b2 Fe 2-b2 M2 b2 (PO x2 ) y2 Formula II where in formula II M2 is selected from one or more of the elements Ti, Zr, Hf, Ge and Sn with a valency of +4, where 0 ≤ b2 ≤ 1, 3 ≤ x2 ≤ 5, 2 ≤ y2 ≤ 4. [25] A battery cell according to claim 24, characterized by , that the fast ion conductor comprises one or more of Li2FeTi(PO4)3, Li2FeZr(PO4)3, Li2FeSn(PO4)3. [26] A battery cell according to any one of claims 1 to 25, characterized by that the positive active material meets at least one of the following conditions: (1) wherein the positive active material under a pressure of 30000 N achieves a powder compaction density greater than or equal to 2.46 g / cm³ 3 , optional 2.46 g / cm² 3 - 2.8 g / cm³ 3 exhibits (2) wherein the volume-averaged particle size of the positive active material satisfies the following conditions: 1 µm ≤ Dv50 positiv ≤ 2 µm, 0.4 µm ≤ Dv10 positiv ≤ 0.7 µm, (3) wherein the specific powder resistance of the positive active material is ≤ 27.5 Ω•cm, (4) where the specific surface area S of the positive active material is 5 m 2 / g - 18 m 2 / g. [27] A battery cell according to any one of claims 1 to 26, characterized by, that the positive active layer comprises a lithium supplement, wherein the lithium supplement comprises at least one 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. [28] A battery cell according to claim 27, characterized by that the ternary lithium supplement material comprises the general formula as shown in Formula III, Li x3 A y3 Ni a3 Co b3 Mn c3 M3 (1-a3-b3-c3) Y z3 , Formula III, where 0 ≤ x3 ≤ 2.1, 0 ≤ y3 ≤ 2.1 and 0.9 ≤ x3 + y3 ≤ 2.1; 0 ≤ a3 ≤ 1, 0 ≤ b3 ≤ 1, 0 ≤ c3 ≤ 1 and 0.1 ≤ a3 + b3 + c3 ≤ 1; 1.8 ≤ z3 ≤ 3.5; where 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. [29] A battery cell according to claim 27 or 28, characterized by , that the mass fraction of the added lithium supplement in the positive membrane layer is 0.1% - 10%. [30] A battery cell according to any one of claims 1 to 29, characterized by, that the positive electrode plate comprises a positive conductive layer arranged between the positive current collector and the positive active layer, wherein the thickness of the positive conductive layer is 0.5 µm ~ 2 µm; and / or wherein the negative electrode plate comprises a negative conductive layer, wherein the negative conductive layer is arranged between the negative current collector and the negative active layer, wherein the thickness of the negative conductive layer is 0.5 µm ~ 2 µm. [31] A battery cell according to claim 30, characterized by, that the positive conductive layer comprises a conductivity agent and a first binder, wherein the negative conductive layer comprises a conductivity agent and a second binder, wherein the conductivity agent comprises one or more of the following: superconducting carbon, conductive graphite, acetylene black, carbon black, boron carbon black, carbon dots, carbon nanotubes, graphene and carbon nanofibers, wherein the conductivity agent optionally comprises superconducting carbon and carbon nanotubes, wherein the first binder comprises a fluorine-containing binder and the second binder comprises a water-soluble binder. [32] A battery cell according to claim 31, characterized by, that, based on the total mass of the positive electrically conductive layer, the mass fraction of the conductivity agent in the positive electrically conductive layer is 30% to 50% and the mass fraction of the first binder is 50% to 70%, and / or wherein, based on the total mass of the negative electrically conductive layer, the mass fraction of the conductivity agent in the negative electrically conductive layer is 20% to 40% and the mass fraction of the second binder is 60% to 80%. [33] A battery cell according to any one of claims 10 to 32, characterized by , that the one-sided areal density of the negative active layer is 104 mg / 1540.25 mm 2 up to 180 mg / 1540.25 mm 2 , optional 125 mg / 1540.25 mm 2 up to 167 mg / 1540.25 mm 2 amounts. [34] A battery cell according to any one of claims 10 to 33, characterized by , that the density of the negative active layer at 100% SOC of the battery cell is 1.15 g / cm³3 ~ 1.36 g / cm³ 3 , optional 1.25 g / cm² 3 ~ 1.36 g / cm³ 3 amounts. [35] A battery cell according to any one of claims 10 to 34, characterized by , that the negative active material includes graphite. [36] A battery cell according to claim 35, characterized by , that 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 artificial graphite, wherein the coating comprises amorphous carbon and the composite graphite particles comprise secondary particles. [37] A battery cell according to claim 36, characterized by , that the mass fraction of amorphous carbon in the coating of the composite graphite particles, based on the total mass of the composite graphite particles, is 2% to 5%. [38] A battery cell according to claim 36 or 37, characterized by that the specific powder resistance of the negative active material is less than or equal to 0.04 Ω•cm. [39] A battery cell according to any one of claims 36 to 38, characterized by that the negative active material has a powder compaction density of 1.5 g / cm³ under a pressure of 20000 N 3 up to 1.7 g / cm³ 3 , optionally from 1.55 g / cm² 3 up to 1.65 g / cm³ 3 exhibits. [40] A battery cell according to any one of claims 10 to 39, characterized by , that the negative active material further 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, based on the total mass of the negative active material, is 0.3% to 10%, optionally 1% to 6%. [41] A battery cell according to any one of claims 10 to 40, characterized by, that the specific charging capacity (per gram) of the negative active material is 350 mAh / g to 480 mAh / g. [42] A battery cell according to any one of claims 10 to 41, characterized by , that the negative active layer comprises a first negative active material layer arranged on the surface of the negative current collector and a second negative active material layer arranged on the side of the first negative active material layer facing away from the negative current collector, wherein the second negative active material layer contains composite graphite particles. [43] A battery cell according to claim 42, characterized by that the first negative active material layer comprises one or more composite graphite particles and natural graphite. [44] A battery cell according to claim 42, 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. [45] A battery cell according to any one of claims 42 to 44, 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. [46] A battery cell according to any one of claims 42 to 45, 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. [47] A battery cell according to any one of claims 1 to 46, 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 less than or equal to 12 µm, optionally less than or equal to 9 µm. [48] ​​A battery cell according to claim 47, characterized by that the porosity of the porous base membrane in the separation membrane is 20% - 70%, optionally 35% - 60%. [49] A battery cell according to claim 47 or 48, 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. [50] A battery cell according to claim 49, characterized by that the non-fluorinated polymer particles comprise acrylate copolymers. [51] A battery cell according to any one of claims 1 to 50, characterized by, that the liquid supply coefficient of the battery cell is 2.4 g / Ah - 3.1 g / Ah. [52] A battery cell according to any one of claims 1 to 51, characterized by , that the battery cell further comprises electrode terminals, wherein the electrode assembly comprises an electrode tab which is directly welded to the electrode terminal. [53] A battery cell according to any one of claims 1 to 52, characterized by , that the time required to charge the battery cell from a state of charge (SOC) of 10% to a state of charge (SOC) of 80% at 30°C is 6 minutes ~ 15 minutes. [54] A battery cell according to any one of claims 1 to 53, characterized by , that the battery cell has a wound structure, wherein the thickness of the positive current collector is less than or equal to 15 µm and the thickness of the negative current collector is less than or equal to 6 µm. [55] A battery cell according to any one of claims 1 to 54, characterized by, that the volume energy density of the battery cell is 400 Wh / L ~ 500 Wh / L. [56] A battery unit comprising a battery cell according to any one of claims 1 to 55, wherein the battery unit comprises at least one of the following elements: a battery module, a battery pack or an energy storage battery. [57] An electrical device comprising a battery cell according to any one of claims 1 to 56.

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