Battery cell, battery device, power-consuming device and energy storage device

Abstract

Battery cell, characterized in that it comprises a stacked electrical core and a housing, wherein the stacked electrical core is received in the housing, the housing being a soft packing material; wherein the housing comprises a first sealing zone, the first sealing zone being arranged at at least one end of the stacked electrical core extending in a width direction; wherein the first sealing zone comprises a double-folded edge structure extending along a length direction, the double-folded edge structure being provided with an encapsulation adhesive, the encapsulation adhesive being arranged continuously along the length direction and securing the double-folded edge structure; wherein the stacked electrical core comprises a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer provided on at least one side of the cathode collector, wherein the cathode film layer comprises lithium-containing transition metal phosphate particles, wherein at least a part of the surface of the lithium-containing transition metal phosphate particles is provided with a carbon material; where, with reference to the total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-50%; where the thickness of the cathode film layer on one side is designated as H and H is 70 µm-120 µm; where the density of the cathode film when the battery cell is in a fully discharged state is 2.3 g / cm³ 3-2.6 g / cm² 3 amounts; wherein the electrolyte comprises a solvent, wherein the solvent comprises dimethyl carbonate (DMC); where, based on the total mass of the electrolyte, the percentage mass fraction of dimethyl carbonate is 18%-32%.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of batteries, in particular a battery cell, a battery device, a power-consuming device and an energy storage device. STATE OF THE ART

[0002] In recent years, battery cells have been widely used in energy storage systems such as hydroelectric, thermal, wind and solar power plants, as well as in a variety of fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc.

[0003] With the doubling of requirements for the capacity and reliability of power-consuming devices by government, industry standards, and the market, higher demands have been placed on battery cells. However, achieving simultaneous improvements in these performance levels with current technology is difficult, which has become a technical problem that urgently needs to be solved in this field. DISCLOSURE OF REGISTRATION

[0004] In view of the above problems, the present application provides a battery cell, a battery device, a power-consuming device and an energy storage device, which are described below.

[0005] A first aspect of the present application provides a battery cell comprising a stacked electrical core and a housing, wherein the stacked electrical core is received in the housing, the housing being a soft packing material; wherein the housing comprises a first sealing zone, the first sealing zone being arranged at at least one end of the stacked electrical core extending in a width direction; wherein the first sealing zone comprises a double-folded-edge structure extending along a length direction, the double-folded-edge structure being provided with an encapsulation adhesive, the encapsulation adhesive being arranged continuously along the length direction and securing the double-folded-edge structure;wherein the stacked electrical core comprises a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer provided on at least one side of the cathode collector, wherein the cathode film layer comprises lithium-containing transition metal phosphate particles, wherein at least a portion of the surface of the lithium-containing transition metal phosphate particles is provided with a carbon material; wherein, based on a total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-50%; wherein a one-sided thickness of the cathode film layer is designated as H and H is 70 µm-120 µm; wherein the density of the cathode foil when the battery cell is in a fully discharged state is 2.3 g / cm³; 3 -2.6 g / cm² 3is; wherein the electrolyte comprises a solvent, wherein the solvent comprises dimethyl carbonate (DMC); wherein, based on the total mass of the electrolyte, the percentage by mass of dimethyl carbonate is 18%-32%.

[0006] The gram capacity of lithium-containing transition metal phosphate is relatively low, and research has shown that it is difficult to satisfy market demand when the one-sided thickness of the cathode film layer H is less than 70 µm. In the embodiments of the present application, controlling the one-sided thickness H of the cathode film layer in the range of 70 µm to 120 µm makes it advantageous to increase the space utilization rate of the active material and to use a soft packing material in the casing to reduce the weight of the battery cell and improve the mass energy density of the battery.However, the thicker cathode film layer undergoes significant volume changes due to lithium embedding and discharging during charge / discharge cycles. This leads to an accumulation of mechanical stresses, triggering expansion and contraction of the electrode material, electrode foil rebound, and an increase in thickness, which in turn increases mechanical stresses on the encapsulation structure. Simultaneously, the thicker film layer means it is more difficult to conduct internal heat, easily leading to localized overheating. This exacerbates electrolyte side reactions and gas generation, further increasing the internal pressure of the battery cell.The stacked electrical core structure reduces corner gaps and improves volumetric energy density compared to a wound electrical core. However, the stacked electrical core lacks the bonding effect provided by the wound structure, and the rebound constraint of the thick coated film layer is low, which reduces the reliability of the battery cell. Compared to hard-shell materials, soft packing materials have lower mechanical strength and a weaker ability to withstand internal pressure. Simultaneously, the thermal conductivity of soft packing materials is lower, so heat buildup is more likely to occur inside the battery cell, further exacerbating the problem of gas generation. With long-term use, the sealing zone can be washed out due to the high internal pressure.

[0007] The embodiments of the present application further improve the sealing strength of the first sealing zone by incorporating a double-folded edge structure extending along the longitudinal direction within the first sealing zone. This double-folded edge creates multiple sealing barriers by doubly folding and encapsulating the soft packing material of the casing. Even if the first folded edge structure fails due to rebound stress caused by the high thickness of the cathode film layer in the electrical core and electrolyte gas generation, the second folded edge structure maintains the seal. Simultaneously, the soft packing materials are bonded by thermal melting during battery processing, and the double-folded edges can make the heat-sealed zone more uniform and improve the sealing of areas that are not optimally sealed.The sealing area is the weakest link in the mechanical strength of the soft-packed electrical core, and to further improve the reliability of the packaging, the inventor applies encapsulation adhesive to the double-folded edge structure. The adhesive is applied continuously along the length of the double-folded edge structure, bonding it in place. This bonding action can cover microscopic cracks or defects in the heat-sealed area of ​​the soft packaging material. After heat sealing, the double-folded edge structure retains some elastic memory and can spring back after long-term use. The encapsulation adhesive then bonds the double-folded edge structure, maintaining its stability.In the embodiments of the present application, controlling the battery cell in a fully discharged state enables the electrode film density to be between 2.3 g / cm³ and 2.6 g / cm³. This ensures that the battery cell has a high capacity and that the stacked particle structure provides a certain buffer space between the particles, thereby reducing the stress exerted by the electrode film on the encapsulation structure. To further reduce the internal stresses of the battery cell, the inventors regulate the area fraction of particles with a particle size R1 of ≥ 1000 nm in the cathode film layer and the mass fraction of dimethyl carbonate in the electrolyte.The inventors discovered that, at the same expansion rate, the expansion of smaller particles is more easily absorbed by the tiny pore structure between them than that of larger particles. Furthermore, the absolute value of the change in expansion of larger particles is greater and therefore more difficult to dissipate. If the percentage of surface area of ​​particles with a particle size R1 of ≥ 1000 nm exceeds 50%, stress concentration, significant rebound, and an increase in the internal pressure of the battery cell can easily occur. If the surface area of ​​particles with a particle size R1 of ≥ 1000 nm is less than 12%, this will limit the gradation of the cathode film layer and the improvement in packing density, and will not effectively improve battery capacity.Therefore, controlling the surface area fraction of particles with a particle size R1 of R1 ≥ 1000 nm to 12%–50% is beneficial for further improving battery cell reliability while also considering energy density. While dimethyl carbonate has many advantages such as low viscosity, excellent low-temperature performance, and low cost, its mass fraction in the electrolyte is below 18%, making it difficult to create a low-viscosity system. It is also difficult to improve the overall ionic conductivity of the electrolyte, which increases the ohmic impedance within the battery and leads to greater Joule heating. Furthermore, the antioxidant capacity of chain carbonate esters is weak, and the symmetrical structure of dimethyl carbonate is more prone to degradation under high voltages or high temperatures.The mass fraction of dimethyl carbonate is higher than 32%, and gas generation during long cycles is significant, increasing the likelihood of encapsulation failure. Controlling the mass fraction of dimethyl carbonate in the electrolyte to 18%–32% compensates for the electrolyte's low viscosity and the risk of gas generation. Through the synergistic effect of the aforementioned technical measures, a balance between battery energy density and reliability has been achieved.

[0008] In each embodiment, a one-sided thickness of the cathode film layer is designated as H, where H is 90 µm-120 µm, optionally 100 µm-120 µm.

[0009] The one-sided thickness of the cathode film layer lies within the range mentioned above, which contributes to a further improvement in energy density. The applicant found that if the one-sided thickness of the cathode film layer exceeds 100 µm, the phenomenon of rebound in the electrode foil is more severe. The embodiments of the present application strengthen the structural rigidity of the housing through the double-folded-edge structure of the first sealing zone, reduce the probability of the seal being washed out due to the internal stress of the film layer rebound, and the battery achieves a higher energy density and improved reliability.

[0010] In each embodiment, the housing comprises at least one second sealing zone, wherein the second sealing zone is provided at at least one end of the stacked electrical core along the longitudinal direction of the housing, and wherein the second sealing zone is provided on one side of the electrode tab of the stacked electrical core.

[0011] The second sealing zone is located on the side of the electrode tab. The electrode tab must be connected to a lead element, and the connection strength of the lead element and the housing material is relatively weak, so that the gas can easily be flushed out of the second sealing zone. This contributes to achieving directed pressure relief of the battery, reducing the effects of seal failure on the adjacent electrical core, and improving the overall safety and reliability of the battery device.

[0012] In each embodiment, a plurality of adhesive rings circumferentially arranged in the width direction are provided around an outer circumference of the stacked electrical core, wherein the adhesive rings circumferentially arranged in the width direction are provided at intervals along the length direction.

[0013] The spaced arrangement of the adhesive rings, which circumferentially run along the width direction of the battery cell in the longitudinal direction, is conducive to increasing the bonding force for the electrical core, is particularly suitable for battery cells with a thick coated film layer, and is able to effectively reduce the rebound rate of the cathode film layer and the rebound pressure for the sealing zone, thereby further reducing the probability of sealing zone failure and improving the reliability of the battery cells.

[0014] In each embodiment, the percentage area fraction of particles with a particle size R1 of R1 ≥1000 nm is 12%-37%, based on the total area of ​​the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil.

[0015] If the area fraction of the particles with a particle size R1 of R1 ≥1000 nm is within the above range, the expansion force exerted by the rebound of the large particles on the soft packing material and the sealing zone is further reduced and the reliability of the battery cell is improved.

[0016] In each embodiment, the median L in the cumulative distribution curve of the sphericity surface of the particles with a particle size R1 of R1≥1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is R1A50 Sphericity 0.6-0.8, optionally 0.65-0.75, further optionally 0.67-0.75.

[0017] In the cumulative distribution curve of the sphericity area of ​​particles with a particle size R1 of R1≥1000 nm, L lies R1A50 in the above area, and the particles are approximately spherical and easy to roll, so that the volume change caused by the rebound of the thick cathode film layer or the expansion during charging and discharging can be compensated for by rearranging the stacking relationship within a certain spatial area, and the stress on the first sealing zone is reduced to improve the reliability of the battery cell.

[0018] In each embodiment, the distribution uniformity of the particles with a particle size R1 of R1≥1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is less than or equal to 5%, optionally 0.2%-2%, further optionally 0.2%-0.9%.

[0019] The distribution uniformity of particles with a particle size R1 of R1≥1000nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which effectively reduces the degree of stress concentration in the local area of ​​the film layer, so that the rebound stress during the cycling process of the thick-coated film layer can be distributed uniformly over the entire area of ​​the film layer, thereby reducing the rebound rate of the cathode film layer, thus reducing the probability of failure of the encapsulation structure and simultaneously improving the energy density of the battery, thereby increasing the reliability of the battery.

[0020] In each embodiment, the solvent in the electrolyte further comprises one or both of ethyl methyl carbonate (EMC) and ethylene carbonate (EC).

[0021] In each embodiment, the percentage by mass of ethyl methyl carbonate (EMC) is 39%-49%, based on the total mass of the electrolyte.

[0022] The viscosity of ethyl methyl carbonate (EMC) is 0.65 mPa-s at 25°C, which is higher than that of DMC but lower than that of EC. It maintains good mobility even at low temperatures and, together with DMC, reduces the overall viscosity of the electrolyte, thus improving the transfer rate of lithium ions in the electrolyte and reducing Joule heating. Furthermore, EMC has higher oxidative and thermal stability compared to DMC, which further reduces gas generation during electrolyte decomposition and improves the reliability of the battery cell.

[0023] In each embodiment, the percentage by mass of ethylene carbonate (EC) is 13%-22%, based on the total mass of the electrolyte.

[0024] Ethylene carbonate (EC) has a very high dielectric constant, which can effectively dissolve lithium salts, improve the ionic conductivity of the electrolyte and ensure the smooth transfer of lithium ions. Furthermore, EC in the above range of mass fraction can decompose and form a stable SEI film on the surface of the active anode material, reducing side reactions and improving cycle lifetime.

[0025] In each embodiment, the total percentage by mass of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) is 52%-71%, based on the total mass of the electrolyte.

[0026] The total mass content of EC and EMC lies within the above range, which can complement each other to overcome the problems of the higher viscosity of EC and the poorer thermal stability and mechanical strength of the SEI film formed by EMC, in order to optimize the performance of the electrolyte and to further reduce the pressure of Joule heating and gas generation through the decomposition of the SEI film on the sealing zone from the direction of optimizing ionic conductivity and the SEI film.

[0027] In each embodiment, the electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6) and the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / L - 1.2 mol / L.

[0028] Lithium hexafluorophosphate (LiPF6) is highly soluble in carbonate ester solvents and forms a high electrolyte concentration to ensure high ionic conductivity of the lithium ions in the electrolyte and to induce the formation of a stable SEI film at the low-potential anode, thus reducing lithium deposition and improving cycle lifetime. If the lithium hexafluorophosphate concentration is too high, the viscosity of the electrolyte increases significantly, restricting lithium ion diffusion and decreasing ionic conductivity. Meanwhile, the decomposition products of lithium hexafluorophosphate, including PF5, react with trace amounts of water in the electrolyte to generate RF, which corrodes the electrodes and SEI films and exacerbates solvent decomposition for gas generation.The concentration of lithium hexafluorophosphate in the above range can achieve the best balance in terms of ionic conductivity and electrolyte stability.

[0029] In each embodiment, the percentage by mass of dimethyl carbonate is 18%-26%, based on the total mass of the electrolyte.

[0030] The mass fraction of dimethyl carbonate is within the above range, and the introduction of EC and EMC with a larger proportion further reduces the ability and probability of gas generation and improves the long-term reliability of the battery cell.

[0031] In some embodiments, the median is C 50 of the degree of graphitization in the cumulative distribution curve for the graphitization C value of the cathode film layer obtained in the area-scanning mode of the laser microconfocal Raman spectrometer, 0.95–1.20; where the graphitization C value I G / I Dis, where I G for the intensity of the G-peak of the Raman spectrum at 1580±100cm -1 and I D for the intensity of the D-peak of the Raman spectrum at 1350±100cm -1 stands.

[0032] Research has shown that the stress on the film layer during cyclic expansion most likely leads to an increase in internal mechanical pressure, causing the encapsulation structure to fail. By controlling the median C 50The graphitization degree in the cumulative distribution curve for the graphitization C value of the cathode film layer, obtained in the area scanning mode of the laser microconfocal Raman spectrometer, is 0.95-1.20. This improves the graphitization degree of the cathode film layer, the degree of particle slippage in the cathode film layer, the phenomenon of stress concentration during the pressing process of the thickly coated film layer, and the degree of cathode film layer rebound during the cycle process due to local stress concentration. This increases the reliability of the battery cell while improving the volume energy density of the battery cell.

[0033] In each embodiment, the median B is 50of the coating value in the cumulative distribution curve for the coating value-B of the cathode film layer, obtained in the area scanning mode of the laser microconfocal Raman spectrometer, 0.30-0.60; where the coating value-B I P / I D is, where I P for the intensity of the P-peak of the Raman spectrum at 948±100cm -1 and I D for the intensity of the D-peak of the Raman spectrum at 1350±100cm -1 stands.

[0034] The median B 50The coating value of the cathode film layer lies within the above range, indicating that the carbon material on the surface of the active cathode material is relatively dense and uniform, which contributes to improving the uniformity of cathode film layer slippage during roller pressing, reducing the phenomenon of stress concentration in the cathode film layer, reducing the degree of cathode foil rebound, and increasing the reliability of the battery cell.

[0035] In each embodiment, the lithium-containing transition metal phosphate particles comprise iron, wherein the cathode film layer has an iron dissolution rate of 658 ppm-1921 ppm, optionally 658 ppm-1485 ppm.

[0036] The iron dissolved in the cathode film layer originates primarily from the lithium-containing transition metal phosphate of the active cathode material. The iron dissolution rate depends on both the number of lattice defects in the lithium-containing transition metal phosphate and the completeness and density of the carbon material on the surface of the active cathode material. The lower the iron dissolution rate, the fewer the lattice defects in the lithium-containing transition metal phosphate, which reduces lattice corrosion in the weakly acidic environment. Conversely, the more complete and dense the carbon material on the surface of the active cathode material, which inhibits the dissolution of iron ions in the weakly acidic environment.The cathode film layer with an iron dissolution rate within the above range exhibits relatively few lattice defects, and the carbon material on the surface of the active cathode material is complete and dense, which is conducive to improving the compression resistance and the degree of easy particle slippage in the cathode film layer under high rolling pressure, increasing the compression density of the cathode film layer and reducing the stress concentration in the cathode film layer, thus improving the energy density of the battery and improving the reliability of the battery.

[0037] In each embodiment, the cathode film layer further comprises a conductive agent, wherein, with respect to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the proportion of the total area of ​​an agglomeration region of the conductive agent is 0.5%-2.5%, optionally 0.5%-1.7%.

[0038] Based on the total cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the proportion of the total area of ​​the agglomeration zone of the conductive medium is 0.5%-2.5%, which indicates that the conductive medium is uniformly dispersed in the cathode film layer and it is easy to form a homogeneous conductive network, which particularly helps to reduce the problem of reduced kinetics in a thick-coated film layer due to the increase in ion transfer paths, and to reduce local polarization or even lithium precipitation of the battery during the cycling process.At the same time, research has shown that the lithium-containing transition metal phosphate particles in the large particle size are easily rebounded; the agglomeration area of ​​the conductive agent in the above area may be able to inhibit the rebound of the lithium-containing transition metal phosphate by means of the uniform distribution of the conductive agent in order to form a mechanical bond of the particles and even of the film layer, improve the cohesion of the film layer, reduce the probability of failure of the sealing area and improve the reliability of the battery.

[0039] In each embodiment, the conductive means comprises carbon nanotubes, wherein the carbon nanotubes comprise one or more of single-walled carbon nanotubes, thin-walled carbon nanotubes, or multi-walled carbon nanotubes.

[0040] Due to the structural properties of carbon nanotubes with a high length-to-diameter ratio, it is advantageous to overlap multiple cathode particles and particles in the thickness direction to form a long-range conductive path and simultaneously improve the bonding force between the particles. This not only contributes to improving the kinetic performance of the thick-coated cathode film layer, but also to reducing local polarization and even lithium precipitation problems that arise during the battery cycling process, thus improving the battery cycle life. It can also be used as a bridge for voltage propagation, as it is capable of forming a network structure in the cathode film layer, effectively reducing voltage concentration, decreasing the degree of electrode foil rebound, and improving the reliability of the battery cell.Simultaneously, carbon nanotubes possess a high specific surface area and a hollow structure, resulting in excellent fluid retention capacity. The extensibility of the thick electrode film during the cycling process is significant, facilitating easy electrolyte extrusion. Carbon nanotubes in the cathode film layer contribute to improving the fluid retention capacity of the thick electrode film, mitigating the phenomenon of capacity degradation during the battery cell's cycling process, and extending the battery cell's cycle life.

[0041] In each embodiment, the conductive medium further comprises conductive carbon black.

[0042] Conductive carbon black has a high specific surface area and therefore good liquid retention capacity. The expansion force of the thick electrode foil during the cycling process is high, which allows the electrolyte to be easily extruded. The distribution of conductive carbon black in the cathode film layer helps to improve the liquid retention capacity of the thick electrode foil, mitigate the phenomenon of capacity loss during the battery's cycling process, and improve the battery's cycle life.

[0043] In each embodiment, the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black.

[0044] The researchers found that carbon nanotubes, due to their high surface energy, tend to agglomerate, leading to an uneven distribution in the cathode film layer and preventing the formation of an effective network structure of carbon nanotubes. Conductive carbon black, with a surface energy close to that of carbon nanotubes, can be adsorbed onto their surface to form a physical barrier. This increases resistance to agglomeration, reduces direct contact between the carbon nanotubes, and thus inhibits the agglomeration phenomenon, thereby improving the uniformity of carbon nanotube distribution within the cathode film layer.On the one hand, this helps to improve the electrical conductivity of the thick-coated cathode film layer and the kinetic performance of the battery; on the other hand, it helps to exert the binding effect of the carbon nanotubes on the cathode film layer, reducing the risk of the thick-coated cathode film layer delaminating and further improving the kinetic performance and lifetime of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive agent also leads to the blocking of the local ion transfer pathway in this region, and the collocation of conductive carbon black can improve the lithium-ion transfer capacity in this region, reduce local polarization, and further improve the cycle stability of the battery.

[0045] In each embodiment, the mass fraction C1 of the carbon nanotubes, relative to the mass of the cathode film layer, is 0. <C1≤2,5% und der Massengehalt C2 des leitfähigen Rußes 0<C1≤2,5%.

[0046] The mass content of carbon nanotubes and conductive carbon black in the cathode film layer within the above range can effectively reduce the agglomeration phenomenon of the carbon nanotubes and form a good conductive network structure, thereby effectively reducing the voltage concentration of the cathode film layer and improving the reliability of the battery cell; the retention rate of electrolyte solution of the cathode film during long cycles is improved, thereby reducing the degree of polarization and improving the capacity of the battery cell.

[0047] In each embodiment, the cathode film layer further comprises a dispersing agent, wherein the dispersing agent comprises hydrogenated nitrile butadiene rubber HNBR.

[0048] HNBR is obtained from nitrile rubber by hydrogenation of saturated double bonds, and its highly saturated main-chain structure gives it excellent oil resistance, heat resistance, and aging resistance, among other properties. This makes it stable in various environments and systems when used as a dispersant, and it does not degrade or degrade easily, allowing it to effectively perform the role of a dispersion agent. The HNBR molecular chain contains both polar nitrile groups and nonpolar hydrocarbon chain segments. The polar nitrile group can interact with the hydroxyl group (-OH) or the metal oxide sites on the surface of the lithium-containing transition metal phosphate particles (e.g., in lithium-containing phosphate groups).Hydrogen bonding, dipole effect) to improve particle compatibility with the solvent and reduce interfacial tension between the particles and the solvent, especially interfacial tension for large particles. In this way, the particles can be dispersed more easily and uniformly, thereby reducing aggregation due to hydrophobicity, improving the dispersion of large particles in the cathode film layer, and reducing the stress concentration caused by rebound. The nonpolar hydrocarbon chain segments, on the other hand, have good lipophilicity and can be readily stretched and dispersed in nonpolar or weakly polar media, so that the particles are uniformly dispersed in the media.When HNBR is adsorbed onto the surface of particles in the slurry, its long-chain molecules form a physical barrier around the particles, preventing them from approaching and aggregating. This allows the particles to remain relatively independent and dispersed within the system. Simultaneously, HNBR can reduce the surface tension between the dispersion medium and the dispersed particles, making it easier for the particles to be moistened by the medium. This promotes particle dispersion, and it can also reduce the interfacial energy between the particles. This, in particular, reduces the aggregation of the conductive medium due to interfacial energy-driven phenomena and improves the cycle life of the battery cell.

[0049] In each embodiment, the mass content of the conductive medium is 0.5%-2%, based on the mass of the cathode film layer.

[0050] The mass fraction of the dispersant is within the above range, which allows for a uniform dispersion of the particles in the cathode film layer, while maintaining a high charge capacity of the cathode film layer, and slows down the rebound caused by the voltage concentration in the thickly coated cathode film layer of the lithium-containing transition metal phosphate, thereby reducing the rebound rate of the cathode film layer and improving the reliability of the battery cell.

[0051] In each embodiment, the porosity of the cathode film layer is 14%-28%.

[0052] The porosity of the cathode film layer lies within the above range, which is beneficial for improving the electrolyte fluid retention properties, enhancing the ion diffusion capacity of the thickly coated electrode foil and cathode film layer, and also improving the battery's kinetic performance. Furthermore, it can cushion volume expansion during rebound or charge / discharge, reduce the effects of expansion stress on the sealing zone, and maintain the battery's high reliability.

[0053] In each embodiment, the battery cell further comprises a separator arranged between the cathode foil and the anode foil, wherein the separator comprises a base film, a ceramic layer provided on both sides of the base film, and a bonding layer provided on at least one of the sides of the ceramic layer facing away from the base film, wherein the bonding layer is a continuous layer with a porous structure, and wherein the bonding layer comprises a vinylidene fluoride polymer.

[0054] The separator provided by the embodiments of the present application uses a continuous layer with a porous structure as a bonding layer, which has a larger bonding area than the bonding layer in the prior art, thereby making the bond between the separator and the cathode film layer stronger and more uniform; the particles with a particle size R1≥1000nm are susceptible to the problem of rebound due to stress concentration during the cycling process.The separator provided by the embodiments of the present application uses a continuous layer with a porous structure as a bonding layer, which is particularly suitable for the thick-coated stacked electrical core. This improves the rebound of the thick-coated stacked electrical core during long cycles and reduces the expansion stress within the battery, thereby enhancing the reliability of the sealing zone and the battery cell as a whole. Furthermore, during the pulling of the outer electrode foil and the welding of the electrode tab, a relative displacement of the thick-coated core occurs between the electrode foil and the separator. This causes the film layer to be prone to powder deposition and can even lead to overlapping of the cathode and anode, creating a risk of internal short circuits.The continuous layer with a porous structure as a binder layer in the embodiments of the present application also reduces the aforementioned risk.

[0055] In each embodiment, the cathode film layer is provided with a lower coating layer at a lower region facing the cathode collector, wherein the lower coating layer satisfies at least one of the following conditions: (1) the lower coating layer comprises a conductive agent and a binder, wherein the conductive agent comprises carbon nanotubes and conductive carbon black, and wherein the binder comprises a vinylidene fluoride polymer; (2) the thickness of the lower coating layer is 0.5 µm-5 µm.

[0056] The lower coating layer provided in the embodiments of the present application contributes to improving the adhesion between the cathode film layer and the cathode collector and to reducing the phenomenon of voltage concentration at the large particles, thereby reducing the rebound of the cathode film layer and improving the reliability of the battery cell. At the same time, compared to direct contact between the cathode collector and the cathode film layer, the contact area between the lower coating layer and the cathode film layer is increased, which contributes to increasing the electron transfer area between the collector and the cathode film layer, thereby reducing the internal resistance of the electrode foil and improving the kinetic performance of the battery.

[0057] In each embodiment, the lithium-containing transition metal phosphate particles in the cathode film layer comprise a component with the following general formula: LimFe x P y O j Q q , where Q comprises one or more of Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, Cl, Br, and where 0.8≤m≤1.15, 0.9≤x≤1, 0.95≤y≤1, 3.5≤j≤4, 0 <q≤0,1 ist.

[0058] The selection of the appropriate modification element Q can improve the lattice change rate of the active cathode material in the process of de-embedded lithium, reduce the oxygen activity on the surface of the particles, improve the structural stability of the material and thereby improve the level of the gram capacity play of the material during the cycle and improve the cycle stability of the battery cell.

[0059] In each embodiment, the lithium-containing transition metal phosphate particles comprise titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of titanium is 500 ppm-8000 ppm, optionally 1000 ppm-3000 ppm.

[0060] The introduction of titanium into lithium-containing transition metal phosphate particles requires the addition of a titanium source during the fabrication of the active cathode material. This titanium source is often an inert material that adheres to the surface of the lithium-containing transition metal phosphate to reduce reactivity and particle size growth. Increasing the degree of graphitization of the active cathode material often necessitates a higher sintering temperature or a longer sintering time, which, however, also increases the particle size in the cathode film layer, raises the stress concentration in the cathode film layer, and triggers the phenomenon of cathode film delamination.In the embodiments of the present application, the addition of a high titanium content to the lithium-containing transition metal phosphate particles reduces the reactivity of the synthetic raw material of the active cathode material, resulting in a high degree of graphitization of the active cathode material. This also allows for control of the proportion of large particles, reduces the rebound rate of the cathode film layer, and improves the energy density of the battery, thereby enhancing battery reliability. Simultaneously, the titanium doping in the active cathode material leads to lattice distortion, reduces the Li-O bond energy, increases the diffusion rate of lithium ions, and improves the kinetic performance of the battery.The uneven diffusion of lithium ions in the thick-coated film layer is often accompanied by significant lithium ion concentration gradients, and the embodiments of the present application improve the solid-phase transfer rate of the active cathode material by adding a high titanium content to the lithium-containing transition metal phosphate particles to improve the kinetics of the battery with a thick electrode foil.

[0061] In each embodiment, the lithium-containing transition metal phosphate particles comprise vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of vanadium is 500 ppm-5000 ppm, optionally 500 ppm-3000 ppm.

[0062] The vanadium element in the cathode film layer can exist in different valence states, with +5-valent vanadium (V 5+) can be doped with phosphorus sites, which, due to its larger radius, leads to lattice distortions, thus enlarging the lithium-ion diffusion channels and thereby improving the ionic conductivity of the active cathode material, thus improving the kinetic performance of the battery; whereas +3-valent vanadium (V 3+Since the material can be doped with transition metal sites, lithium voids are created through charge compensation, thereby improving the electronic conductivity of the active cathode material. Furthermore, the increased uniformity of vanadium distribution within the lithium-containing transition metal phosphate particles contributes to a further improvement in the kinetic performance and reaction uniformity of the cathode film layer, thus enhancing the kinetic and cycle performance of the battery cell. The vanadium mass content in the above region contributes to improving the kinetic performance of the cathode foil and the kinetic performance of the thick-coated lithium-containing transition metal phosphate battery.At the same time, the synergistic effect of the titanium element, the vanadium element and the carbon nanotubes in the cathode film layer helps to form a good three-dimensional network to further improve the electronic conductivity and the ionic conductivity of the cathode film layer, thereby further improving the kinetic performance of the thick-coated lithium-containing transition metal phosphate battery.

[0063] In each embodiment, the soft packaging material comprises an aluminum-plastic composite film, optionally a composite film formed from one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE) with aluminum.

[0064] In each embodiment, at least one stacked electrical core is accommodated in the housing, wherein the housing has a dimension of L0 in a longitudinal direction, wherein the housing has a dimension of W0 in a width direction, wherein the housing has a dimension of H0 in a thickness direction, wherein 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm, and 14 mm ≤ H0 ≤ 22 mm.

[0065] In each embodiment, the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 450 mm ≤ L0 ≤ 650 mm.

[0066] If the length dimension L0 of the casing meets the criteria of 450 mm ≤ L0 ≤ 650 mm, the battery cell length is shorter. This helps to shorten the current diffusion path and reduce the internal resistance of the electrodes, thereby reducing heat generation in the battery and improving its kinetic performance. Furthermore, the shorter casing length contributes to shortening the electrolyte diffusion path during the infiltration process, improving the infiltration rate and electrolyte uniformity, further promoting the uniformity of lithium ion disembedding during the cycling process, mitigating the phenomenon of voltage concentration, reducing the amplitude of the film layer rebound, and improving the reliability of the battery cell.

[0067] If the dimension Lo of the casing in the longitudinal direction is 450 mm ≤ L0 ≤ 650 mm, the battery cell has a shorter length, which contributes to shortening the electron transfer path and reducing the internal resistance of the battery, while simultaneously reducing the electrolyte infiltration distance in the electrode pores, improving the uniformity of infiltration and increasing the kinetic performance of the thick coated film layer; in particular, under fast charging conditions, it can reduce the phenomenon of uneven temperature rise and current density in the longitudinal direction of the electrode foil.

[0068] In each embodiment, the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 900mm ≤ L0 ≤ 1300mm.

[0069] If the longitudinal dimension L0 of the casing meets the following condition: 900 mm ≤ L0 ≤ 1300 mm, the longer battery cell size helps to reduce the volume fraction of the casing within the battery cell and improve the load-bearing capacity of the active material. Simultaneously, a longer battery cell can reduce the number of batteries required in the battery module, simplify the structural design of the battery module, decrease the number and complexity of structural components within the module, and thereby improve the space utilization rate of the battery pack, which in turn contributes to improving the volumetric energy density of the battery cell.

[0070] In each embodiment, the battery cell capacity at 25°C is 105 Ah-300 Ah, optionally 150 Ah-190 Ah.

[0071] A second aspect of the present application provides a battery device comprising a battery cell according to the first aspect of the present application.

[0072] A third aspect of the present provides a power-consuming device comprising a battery device according to the second aspect, wherein the battery device is used to provide electrical energy.

[0073] A third aspect of the present provides an energy storage device, comprising a battery device according to the second aspect, wherein the battery device is used to store electrical energy. PRESENTATION OF THE REGISTRATION Fig. 1 is a front view of a battery cell in an embodiment of the present application; Fig. Figure 2 is a schematic representation of a separator in an embodiment of the present application; Fig. Figure 3 shows a schematic representation of a separator in the prior art; Fig. Figure 4 shows a schematic representation of a power-consuming device in an embodiment of the present application. 5 battery cells; 50 cases; 51 first sealing zone; 52 second sealing zone; 53 Supply element; 20 Separator; 201 Basic film; 202 Ceramic layer; 203 binder layer; X Longitude direction; Y Latitude direction; Z Thickness direction. SPECIFIC EXECUTION FORMS

[0074] The following sections disclose in detail embodiments of the battery cell, battery device, current-consuming device, and energy storage device of the present application with corresponding reference to the accompanying drawings. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure will be left out. This is to avoid making the following description unnecessarily long and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description serve to provide those skilled in the art with a complete understanding of the present application and are not intended to limit the subject matter specified in the claims.

[0075] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60-120 and 80-110 is specified for a particular parameter, a range of 60-110 and 80-120 is also to be expected. Furthermore, if the minimum values ​​1 and 2 and the maximum values ​​3, 4, and 5 are specified, the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0076] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined to form new technical solutions, and such a technical solution should be considered to be covered by the disclosure of the present application.

[0077] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined to form a new technical solution, and such a technical solution should be considered to be covered by the disclosure of the present application.

[0078] Unless expressly stated otherwise, all steps of the present application may be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the method may also include step (c) means, for example, that step (c) may be added to the method in any order; e.g., the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b).

[0079] In the present application, the terms "plural" and "multiple" refer to two or more.

[0080] Unless otherwise stated, the terms used in this application have the known meanings as generally understood by those skilled in the art.

[0081] Unless otherwise specified, the values ​​of the parameters mentioned in this application can be determined by various test methods commonly used in practice, e.g., according to the test methods specified in the embodiments of this application. Unless otherwise specified, the test temperature for each parameter is 25°C.

[0082] The battery devices in the embodiments of the present application can comprise one or more battery cells to provide a voltage and capacity. The battery cell assembly can comprise a plurality of soft-pack battery cells, wherein the plurality of soft-pack battery cells are connected in series, parallel, or in a mixed configuration by a converging element. For example, the battery cell assembly is typically formed by arranging a plurality of soft-pack battery cells; the battery cell assembly can be a battery module, wherein the battery module comprises a plurality of soft-pack battery cells arranged and secured to form a single module. For example, the battery module can be formed by bonding the multiple battery cells together.

[0083] The battery device can be a battery pack comprising a housing and one or more battery cell assemblies, with the battery cell assemblies being contained within the housing. The battery cell assembly can be a battery module, and the battery cell assembly can be contained within the housing by securing the battery module within the housing; the battery cell assembly can also be contained within the housing by directly securing a plurality of soft-packed battery cells within the housing.

[0084] In the embodiments of the present application, the box can comprise a first box and a second box. The first box and the second box are attached to one another in such a way that an enclosed space is formed inside the box, which accommodates the battery cell assembly. "Enclosed" here means covered or sealed, and this space may be sealed or unsealed. The first box can be a top cover or a bottom plate. For example, the box can comprise a top cover, a frame, and a bottom plate. The top cover and the bottom plate are each connected to the frame, so that an enclosed space is formed inside the box, which accommodates the battery cell assembly.

[0085] In the embodiments of the present application, the box can be part of a chassis structure of the vehicle. For example, parts of the box can be at least part of a floor of the vehicle, or parts of the box can be at least part of a cross member and a longitudinal member of the vehicle.

[0086] In the embodiments of the present application, the battery cell can be a secondary battery, i.e., a battery cell that can be recharged after it has been discharged, so that the active material can be reactivated and reused; the battery cell can be a lithium-ion battery. The battery cell can be flat.

[0087] The batteries mentioned in the embodiments of the present application can comprise one or more battery cells to achieve a higher voltage and capacity. The batteries mentioned in the present application can be, for example, battery cells, battery modules, or battery packs.

[0088] The battery cell is the smallest unit that makes up the battery and is capable of performing the charging and discharging functions on its own. In the case of multiple battery cells, the cells are connected in series, parallel, or a mixed configuration via a sink component. In some embodiments, the battery may be a battery module; in the case of multiple batteries, the cells are arranged and secured to form a single module. In some embodiments, the battery may be a battery pack comprising a housing and a battery cell, with the battery cell or battery module contained within the housing. In some embodiments, the housing may be part of the vehicle's chassis structure.For example, parts of the housing can be at least part of a chassis of the vehicle, or parts of the housing can be at least part of a cross member and a longitudinal member of the vehicle.

[0089] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, and the like.

[0090] In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be multiple, with the exact number being adjustable depending on the application and capacity of the battery module. In some embodiments, the battery modules described above can also be assembled into a battery pack, with the number of battery modules contained in the battery pack being adjustable depending on the application and capacity of the battery pack.

[0091] The battery cell comprises an electrode component and an electrolyte.

[0092] The electrode component typically comprises a cathode foil and an anode foil, the anode foil being the electrode where the reaction of uptake or lithiation of lithium ions during charging and release or delthiation of lithium during discharging takes place, and the cathode foil being the electrode where the reaction of release or delthiation of lithium ions during charging and uptake or lithiation of lithium during discharging takes place.

[0093] Although lithium-containing transition metal phosphate offers a significant advantage in terms of cycle stability as an active cathode material, its intrinsic gram capacity is considerably lower than that of ternary materials. The applicant noted that using a thick coating in electrode fabrication is an effective technical means of compensating for the disadvantage of the low capacity of lithium-containing phosphates, and that the use of a soft-pack housing, which has a lower weight, further improves the theoretical mass energy density of the battery cell.However, this process improvement also brings new technical challenges: Firstly, thicker electrode foils have a higher expansion stress during long-term cycles, and secondly, the heat generated by thicker electrode foils during the operating process is difficult to dissipate effectively. The local occurrence of high temperatures leads to electrolyte decomposition and gas production, which increases the internal pressure of the battery. Due to the limited mechanical strength of the soft-pack housing, the internal expansion and pressure increase can lead to bulging of the battery cell or even to cracking and failure of the housing.

[0094] A first aspect of the present application provides a battery cell, as shown in Fig.Figure 1, comprising a stacked electrical core and a housing 50, wherein the stacked electrical core is contained in the housing 50, the housing 50 being a soft packing material; wherein the housing comprises a first sealing zone 51, the first sealing zone 51 being arranged at at least one end of the stacked electrical core extending in a width direction (Y-direction); wherein the first sealing zone comprises a double-folded edge structure extending along a length direction (X-direction), the double-folded edge structure being provided with an encapsulation adhesive, the encapsulation adhesive being arranged continuously along the length direction (X-direction) and securing the double-folded edge structure;wherein the stacked electrical core comprises a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer provided on at least one side of the cathode collector, wherein the cathode film layer comprises lithium-containing transition metal phosphate particles, wherein at least a portion of the surface of the lithium-containing transition metal phosphate particles is provided with a carbon material; wherein, based on a total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-50%; wherein a one-sided thickness of the cathode film layer is designated as H and H is 70 µm-120 µm; wherein the density of the cathode foil when the battery cell is in a fully discharged state is 2.3 g / cm³; 3 -2.6 g / cm² 3is; wherein the electrolyte comprises a solvent, wherein the solvent comprises dimethyl carbonate (DMC); wherein, based on the total mass of the electrolyte, the percentage by mass of dimethyl carbonate is 18%-32%.

[0095] The gram capacity of lithium-containing transition metal phosphate is relatively low, and research has shown that it is difficult to satisfy market demand when the one-sided thickness of the cathode film layer H is less than 70 µm. In the embodiments of the present application, controlling the one-sided thickness H of the cathode film layer in the range of 70 µm to 120 µm makes it advantageous to increase the space utilization rate of the active material and to use a soft packing material in the casing to reduce the weight of the battery cell and improve the mass energy density of the battery.However, the thicker cathode film layer undergoes significant volume changes due to lithium embedding and discharging during charge / discharge cycles. This leads to an accumulation of mechanical stresses, triggering expansion and contraction of the electrode material, electrode foil rebound, and an increase in thickness, which in turn increases mechanical stresses on the encapsulation structure. Simultaneously, the thicker film layer means it is more difficult to conduct internal heat, easily leading to localized overheating. This exacerbates electrolyte side reactions and gas generation, further increasing the internal pressure of the battery cell.The stacked electrical core structure reduces corner gaps and improves volumetric energy density compared to the wound electrical core. However, the stacked electrical core lacks the bonding effect provided by the wound structure, and the rebound constraint of the thick coated film layer is low, which reduces the reliability of the battery cell. Compared to hard-shell materials, soft packing materials have lower mechanical strength and a weaker ability to withstand internal pressure. Simultaneously, the thermal conductivity of soft packing materials is lower, so heat buildup is more likely to occur inside the battery cell, further exacerbating the problem of gas generation. With long-term use, the sealing zone can be washed out due to the high internal pressure.

[0096] The embodiments of the present application further improve the sealing strength of the first sealing zone by incorporating a double-folded edge structure extending along the longitudinal direction within the first sealing zone. This double-folded edge creates multiple sealing barriers by doubly folding and encapsulating the soft packing material of the casing. Even if the first folded edge structure fails due to rebound stress caused by the high thickness of the cathode film layer in the electrical core and electrolyte gas generation, the second folded edge structure maintains the seal. Simultaneously, the soft packing materials are bonded by thermal melting during battery processing, and the double-folded edges can make the heat-sealed zone more uniform and improve the sealing of areas that are not optimally sealed.The sealing area is the weakest link in the mechanical strength of the soft-packed electrical core, and to further improve the reliability of the packaging, the inventor applies encapsulation adhesive to the double-folded edge structure. The adhesive is applied continuously along the length of the double-folded edge structure, bonding it in place. This bonding action can cover microscopic cracks or defects in the heat-sealed area of ​​the soft packaging material. After heat sealing, the double-folded edge structure retains some elastic memory and can spring back after long-term use. The encapsulation adhesive then bonds the double-folded edge structure, maintaining its stability.In the embodiments of the present application, controlling the battery cell in a fully discharged state enables the electrode film density to be between 2.3 g / cm³ and 2.6 g / cm³. This ensures that the battery cell has a high capacity and that the stacked particle structure provides a certain buffer space between the particles, thereby reducing the stress exerted by the electrode film on the encapsulation structure. To further reduce the internal stresses of the battery cell, the inventors regulate the area fraction of particles with a particle size R1 of ≥ 1000 nm in the cathode film layer and the mass fraction of dimethyl carbonate in the electrolyte.The inventors discovered that, at the same expansion rate, the expansion of smaller particles is more easily absorbed by the tiny pore structure between them than that of larger particles. Furthermore, the absolute value of the change in expansion of larger particles is greater and therefore more difficult to dissipate. If the percentage of surface area of ​​particles with a particle size R1 of ≥ 1000 nm exceeds 50%, stress concentration, significant rebound, and an increase in the internal pressure of the battery cell can easily occur. If the surface area of ​​particles with a particle size R1 of ≥ 1000 nm is less than 12%, this will limit the gradation of the cathode film layer and the improvement in packing density, and will not effectively improve battery capacity.Therefore, controlling the surface area fraction of particles with a particle size R1 of R1 ≥ 1000 nm to 12%–50% is beneficial for further improving battery cell reliability while also considering energy density. While dimethyl carbonate has many advantages such as low viscosity, excellent low-temperature performance, and low cost, its mass fraction in the electrolyte is below 18%, making it difficult to create a low-viscosity system. It is also difficult to improve the overall ionic conductivity of the electrolyte, which increases the ohmic impedance within the battery and leads to greater Joule heating. Furthermore, the antioxidant capacity of chain carbonate esters is weak, and the symmetrical structure of dimethyl carbonate is more prone to degradation under high voltages or high temperatures.The mass fraction of dimethyl carbonate is higher than 32%, and gas generation during long cycles is significant, increasing the likelihood of encapsulation failure. Controlling the mass fraction of dimethyl carbonate in the electrolyte to 18%–32% compensates for the electrolyte's low viscosity and the risk of gas generation. Through the synergistic effect of the aforementioned technical measures, a balance between battery energy density and reliability has been achieved.

[0097] In the present application, the term "double-folded" refers to a reinforcing structure formed by folding the sealing area in opposite directions. By first folding the sealing area and then folding it again along the direction of the first fold or in the opposite direction, the sealing zone is stronger than a single-fold edge structure and can withstand greater internal pressure without being washed out and failing. Further "multiple folding" leads to an exponential increase in process difficulty and cost without a significant improvement in the strength of the sealing area.

[0098] Lithium-containing transition metal phosphate refers to a phosphate material comprising lithium and a transition metal element and can be detected by any known method in this field. For example, it can be detected by a combination of an X-ray diffractometer (XRD) and an energy spectrum analyzer.

[0099] In the present application, the term "particle" refers to particles in the field of view of the cathode film layer at a certain magnification, e.g. 10,000x, with recognizable complete boundaries, whereby defects and scratches may be present within the particles, but no complete boundaries sufficient to subdivide the particles are recognizable within the particles.

[0100] The particle identification procedure is as follows: the cathode film layer is cut by the argon ion beam along the thickness direction of the electrode foil (for example, optional: instrument model: Leica EMTIC3XCP, operating voltage: 6 kV, operating time: 6 h), and after exposing the cut surface, a scanning electron microscope is used (for example, optional: instrument model: Hitachi SU8230, operating voltage: 3 kV, beam current: high, probe model: U (LA100), working distance <5 mm) to observe the cut surface of the cathode film layer along the thickness direction of the electrode foil. The images are acquired with the field emission scanning electron microscope (FESEM) in the non-marginal position of the cut surface of the cathode film layer (after observing the edge of the electrode foil under the scanning electron microscope, the field of view is adjusted to the central part of the sample) in secondary electron mode.The electropherograms are acquired at 10k magnification, and the particles in the electropherograms are analyzed using ImageJ software (1.46r, Win64 version). The ImageJ software is used as follows: loading the scanning electron microscope image to be analyzed; identifying the particles using the Cellpose plug-in software and manually correcting them based on this identification; reading and counting the data using ImageJ. The specific procedure for using the Cellpose plug-in software to identify the particles is as follows: setting the segmentation diameter parameter (diameter in the segmentation module) to 15 pixels, clicking "runcyto3" to identify the particles; the particles in the image that are not identified, not fully identified, or incorrectly identified by the software are manually marked. The particles in the image that are not identified, not fully identified, or incorrectly identified by the software are:The most common reasons for misidentification are: 1. The particles are too large or have scratches on their surface, preventing or incomplete identification; 2. Scratches occur on the particle surface during the argon ion beam sectioning process, and the software may misinterpret these scratches as particle boundaries during identification, leading to an identification error; 3. The particles are too small and therefore cannot be successfully identified; 4. The particles are located at the edge of the electron microscope's field of view, and the edge penetrates the particle's interior, resulting in an incomplete morphology and the identification of only a localized portion instead of the entire particle, leading to an identification error. The aforementioned unidentified or incorrectly identified particles are calibrated manually.and the specific process is as follows: Delete the particles that are located at the edges of the scanning electron microscope environment and are not fully displayed; assess whether or not there is a slit scratch within the other unidentified or misidentified particles, and if there is no slit scratch within a particle, it is assessed as a single particle, and it is manually marked according to the manually observed boundaries of the particles; in response to the presence of a slit scratch within the particle, it is assessed whether the slit scratch runs through the particle, and if it does not run through the particle, it is assessed that it is a single particle, and it is manually marked; in response to the slit scratch running through the particle, it is assessed whether the slit scratch is linear or irregular; in response to the slit scratch being irregular,It is judged to be a boundary between the particles, and the particles are divided along the boundary; in response to the fact that the slit scratch is linear, a contrast comparison is performed; in response to the fact that the contrast comparison is not obvious and there is no cracking effect, the slit scratch is judged to be a scratch, and it is marked as one particle; in response to the fact that the contrast comparison is strong and there is a cracking effect, the slit scratch is judged to be a boundary between the particles, and it is marked as two particles. After manual marking, the information that is not related to the particles in the automatic processing of the image is deleted, i.e., the assessment and marking of the particles in the image is complete.

[0101] It is understood that the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, in particular the particles of 50 nm or more, originate mainly from the active cathode material. Therefore, the embodiment of the present application can accurately and objectively reflect the distribution of the lithium-containing transition metal phosphate particles in the cathode film layer by observing and counting the particle area of ​​the particles in a cross-sectional area of ​​the cathode foil along the thickness direction of the electrode foil.

[0102] In the prior art, the particle size of the active cathode material is usually determined using a laser particle size analyzer based on the Malvern laser diffraction method. However, the applicant's research shows that, because the lithium-containing transition metal phosphate particles readily agglomerate, the test results obtained using the Malvern laser diffraction method based on the laser scattering principle often measure the particle size of the particle agglomerates. This does not accurately reflect the particle size of the particles in the active cathode material, and even less so the dispersion of the active cathode material in the film layer, since the dispersion of the active cathode material in the film layer increases during the roller pressing process for film formation.The test results obtained by the Malvern laser diffraction method are influenced by the particle size, the specific surface area, and the degree of agglomeration of the active cathode material, and the number of large particles obtained by this test is lower than the actual value, and the number of small particles is higher than the actual value, compared to the real dispersion in the electrode foil, so that the particle size obtained by the Malvern laser diffraction method cannot be equivalent or analogous to the particle size obtained by the embodiment of the present application.

[0103] The counting method for the area fraction of particles with a particle size R1 of R1 ≥ 1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil was carried out as follows: The particles in the cathode film layer are detected with reference to the above method of the present application; the image of particle determination and identification is imported into the ImageJ software for analysis, and the scale is set according to the scanning electron microscope image; the particle size, area, sphericity, and roughness of the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil are statistically analyzed using the analysis functions "Feret Diameter," "Area," "Round," and "Solidity." According to the software manual (ImageJUserGuide II 1.46r) The “Feret” parameter obtained from the analysis represents the maximum distance between all parallel lines in the two-dimensional projection of the particles, which is used to characterize the particle size; and the “Area” parameter obtained from the analysis represents the pixel size of the particles. To achieve a statistically significant number of samples, at least 10 scanning electron micrographs were taken for each film layer and at least 1000 particles were counted with respect to particle size.Since particles with a size of less than 50 nm are difficult to identify accurately due to large errors in the statistical process, and since the particle size of the conductive medium is generally less than 50 nm, which can cause large errors in the statistical results, particles with a size of less than 50 nm are not counted in the statistical process for particle size in the present application, and the corresponding "NaN" statistical data displayed for AR, Round, or Solidity are deleted. The sum of the "Area" parameters of the particles with a particle size R1 of R1 ≥ 1000 nm and the sum of the "Area" parameters of all particles were calculated as the area of ​​the particles with a particle size R1 of R1 ≥ 1000 nm and the total area of ​​the counted particles, respectively.The sum of the areas of the particles with a particle size R1 of R1≥1000 nm, divided by the total area of ​​the counted particles, is considered as the percentage area fraction of the particles with a particle size R1 of R1>1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil.

[0104] In some embodiments, based on the total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of particles with a particle size R1 of R1≥1000 nm is optionally 12%, 12.11%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 34.89%, 34.97%, 35%, 36%, 36.71%, 36.75%, 36.83%, 36.92%, 36.95%. 37%, 38%, 38.09%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 49.99%, 50% or any value in a range between any two of these values.

[0105] In some embodiments, the one-sided thickness of the cathode film layer is designated as H, and H is optionally 70 µm, 70.45 µm, 75 µm, 80 µm, 85 µm, 90 µm, 91.88 µm, 95 µm, 96.75 µm, 100 µm, 105 µm, 106.02 µm, 106.09 µm, 106.10 µm, 106.34 µm, 106.66 µm, 106.79 µm, 110 µm, 115 µm, 119.49 µm, 120 µm or any value in a range between any two of these values.

[0106] In some embodiments, when the battery cell is in a fully discharged state, the density of the cathode foil is optionally 2.3 g / cm³. 3 , 2.31 g / cm³ 3 , 2.32 g / cm³ 3 , 2.33 g / cm³ 3 , 2.34 g / cm³ 3 , 2.35 g / cm³ 3 , 2.36 g / cm³ 3 , 2.37 g / cm³ 3 , 2.38 g / cm³ 3 , 2.39 g / cm³ 3 , 2.4 g / cm³ 3 , 2.41g / cm³ 3 , 2.42g / cm³ 3 , 2.43g / cm³ 3 , 2.44g / cm³ 3, 2.45g / cm³ 3 , 2.46g / cm³ 3 , 2.47g / cm³ 3 , 2.48g / cm³ 3 , 2.49g / cm³ 3 , 2.5g / cm³ 3 , 2.51g / cm³ 3 , 2.52g / cm³ 3 , 2.53g / cm³ 3 , 2.54g / cm³ 3 , 2.55g / cm³ 3 , 2.56g / cm³ 3 , 2.57g / cm³ 3 , 2.58g / cm³ 3 , 2.59g / cm³ 3 , 2.6 g / cm³ 3 or any value within a range between two of these values.

[0107] In the present application, a fully discharged state means: storing the battery at 25°C for 2 hours, waiting until the temperature of the battery is maintained at 25°C, and discharging the battery with a constant current of 1 / 3 C to 2.5 V and then discharging the battery with a constant current of 0.1 C to 2.0 V.

[0108] In the present application, the compression density of the cathode foil can be tested according to known methods in the present technical field.As an example, the battery is placed in an oven environment at 25°C and stored for 2 hours. While the battery temperature is maintained at 25°C, it is discharged to 2.5 V at a constant current of 1 / 3 C and then to 2.0 V at a constant current of 0.1 C. The battery is then disassembled to obtain a cathode foil. The remaining electrolyte solution is treated using the solvent dimethyl carbonate. The electrode foil is dried and cut into a small round disc with area S to obtain mass W1. Using a micrometer, the thickness T1 of the cathode foil is measured. The cathode film layer of the weighed electrode foil is then wiped off. The mass of the collector is weighed and recorded as W2. The thickness T2 of the collector is measured using a micrometer. The compression density PD of the cathode foil is then determined. =(W1-W2) / [(T1-T2)×S).

[0109] In some embodiments, the percentage by mass of dimethyl carbonate, based on the total mass of the electrolyte, is optionally 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32% or any value in a range between two of these values.

[0110] In some embodiments, the encapsulation adhesive comprises a long strip of blue adhesive. This long strip of blue adhesive has a high viscosity, which results in a stronger bond to the sealing zone of the casing, further increasing the strength of the first sealing zone and improving the reliability of the battery cell.

[0111] Dimethyl carbonate has good solubility for lithium hexafluorophosphate and, as an electrolyte component, can provide a sufficient lithium ion concentration to meet the necessary conditions for ionic conduction. Furthermore, dimethyl carbonate has a low viscosity, which contributes to improved ionic conductivity of the electrolyte and enhances the multiplication performance and low-temperature performance of the battery cell.

[0112] In each embodiment, the one-sided thickness of the cathode film layer is designated as H, where H is 90 µm-120 µm, optionally 100 µm-120 µm.

[0113] The one-sided thickness of the cathode film layer lies within the range mentioned above, which contributes to a further improvement in energy density. The applicant found that if the one-sided thickness of the cathode film layer exceeds 100 µm, the phenomenon of rebound in the electrode foil is more severe. The embodiments of the present application strengthen the structural rigidity of the housing through the double-folded-edge structure of the first sealing zone, reduce the probability of the seal being washed out due to the internal stress of the film layer rebound, and the battery achieves a higher energy density and improved reliability.

[0114] In some embodiments, such as in Fig.As shown in Figure 1, the housing 50 comprises at least one second sealing zone 52, wherein the second sealing zone 52 is provided at at least one end of the stacked electrical core along the longitudinal direction of the housing, wherein the second sealing zone 52 is provided on one side of the electrode tab of the stacked electrical core.

[0115] It goes without saying that the cathode tab and the anode tab can be located on the same side of the stacked electrical core, as shown in Fig. 4 shown, or that they may be provided on opposite sides of the stacked electrical core.

[0116] In some embodiments, the battery cell 5 further comprises a lead element 53 which is connected to the electrode tabs of the battery cell; for example, the lead element 53 may be welded to the electrode tabs, wherein the lead element 53 is a conductive element; at least a part of the lead element 53 is located outside the housing 50; the lead element 53 acts as an electrode lead end of the battery cell 5; the lead element 53 is used to facilitate the electrical connection of the battery cell 5 to other battery cells 5 or other components. The lead element 53 may, for example, have the form of a sheet.

[0117] Accordingly, the supply element 53 also includes a cathode supply element and an anode supply element, wherein the cathode supply element is connected to the cathode tab and the anode supply element is connected to the anode tab.

[0118] In some embodiments, the second sealing zone is located on the side of the electrode tab, the electrode tab must be connected to a lead element, and the connection strength of the lead element and the housing material is relatively weak, so that the gas can easily be flushed out of the second sealing zone, which contributes to achieving a directed pressure relief of the battery, reducing the effects of seal failure on the adjacent electrical core, and improving the overall safety and reliability of the battery device.

[0119] In some embodiments, a plurality of adhesive rings circumferentially in the width direction are provided around an outer circumference of the stacked electrical core, wherein the adhesive rings circumferentially in the width direction are provided at intervals along the length direction.

[0120] The spaced arrangement of the adhesive rings, which circumferentially run along the width direction of the battery cell in the longitudinal direction, is conducive to increasing the bonding force for the electrical core, is particularly suitable for battery cells with a thick coated film layer, and is able to effectively reduce the rebound rate of the cathode film layer and the rebound pressure for the sealing zone, thereby further reducing the probability of sealing zone failure and improving the reliability of the battery cells.

[0121] In some embodiments, the percentage area fraction of particles with a particle size R1 of R1≥1000nm is 12%-37%, based on the total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil.

[0122] If the area fraction of the particles with a particle size R1 of R1 ≥1000 nm is within the above range, the expansion force exerted by the rebound of the large particles on the soft packing material and the sealing zone is further reduced and the reliability of the battery cell is improved.

[0123] In some embodiments, the median L in the cumulative distribution curve of the sphericity surface of the particles with a particle size R1 of R1≥1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is R1A50 Sphericity 0.6-0.8, optionally 0.65-0.75, further optionally 0.67-0.75.

[0124] The counting method for the sphericity of particles with a particle size R1 of R1 ≥ 1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil was carried out as follows: The particles in the cathode film layer are detected with reference to the above method of the present application; the image of particle determination and identification is imported into the software ImageJ for analysis, and the scale is set according to the scanning electron microscope image; the particle size and sphericity of the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil are statistically analyzed using the analysis functions "Feret Diameter" and "Round". According to the software manual (ImageJUserGuidelJ 1.46r) The “Feret” parameter obtained from the analysis represents the maximum distance between all parallel lines in the two-dimensional projection of the particles, which is used to characterize the particle size. According to the software manual (ImageJUserGuideIJ 1.46r), the “Round” parameter obtained from the analysis represents the ratio of the particle’s pixel area to the area of ​​a circle with the adjusted longitudinal diameter as its diameter, and can characterize the particle’s sphericity. The closer the particle is to a sphere, the closer the ratio of the pixel area to the area of ​​the circle with the adjusted longitudinal diameter as its diameter is to 1. Therefore, the “Round” parameter obtained from the analysis is used to characterize the particle’s sphericity.To achieve a statistically significant number of samples, at least 10 scanning electron micrographs were acquired for each film layer, and at least 1000 particles were counted with respect to particle size. The sphericities of the at least 1000 obtained particles with a particle size R1 of R1 ≥ 1000 nm are arranged in order from smallest to largest value, and the cumulative distribution curve of the particle sphericity in the cathode film layer is obtained by taking the sphericity as the horizontal axis and the cumulative area fraction as the vertical axis. L. RIA50 is a sphericity L value of the particles with a particle size R1 of R1≥1000 nm, if in the cumulative distribution curve of the sphericity L value the cumulative area fraction of the vertical axis is 50%.

[0125] In some embodiments, the median is L R1A50the sphericity in the cumulative distribution curve of the sphericity surface of the particles with a particle size R1 of R1≥1000 nm in the cross-sectional area value of the cathode film layer along the thickness direction of the electrode foil optionally 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.673, 0.68, 0.687, 0.69, 0.7, 0.71, 0.72, 0.73, 0.74, 0.745, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8 or any value in a range between two of these values.

[0126] A person skilled in the art can achieve control of the particle sphericity by any known method. The adjustment of particle sphericity can be achieved, for example, by processes such as comminution, polishing, chemical etching, mechanical mixing, extrusion, coating, granulation, addition of surfactants, etc., as well as by adjusting the parameters of the respective processes.

[0127] In the cumulative distribution curve of the sphericity area of ​​particles with a particle size R1 of R1≥1000 nm, L lies R1450 in the above area, and the particles are approximately spherical and easy to roll, so that the volume change caused by the rebound of the thick cathode film layer or the expansion during charging and discharging can be compensated for by rearranging the stacking relationship within a certain spatial area, and the stress on the first sealing zone is reduced to improve the reliability of the battery cell.

[0128] In some embodiments, the distribution uniformity of the particles with a particle size R1 of R1≥1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is less than or equal to 5%, optionally 0.2%-2%, further optionally 0.2%-0.9%.

[0129] The uniformity of particle distribution with a particle size R1 of R1 ≥ 1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil can be tested using methods known in the technical field. As an example, the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil was divided into three layers of equal thickness along the thickness direction of the electrode foil: a lower layer facing the cathode collector, an upper layer facing away from the cathode collector, and a middle layer located midway between the upper and lower layers. Ten non-overlapping fields of view were selected in each of the upper, middle, and lower layers, and scanning electron micrographs were acquired at a magnification of 10k.The 30 scanning electron microscope images were imported into the software ImageJ for analysis, and 30 values ​​were tested to obtain the percentage area fraction of particles with particle sizes R1 of R1≥1000 nm in each of the 30 images according to the above “test procedure for the percentage area fraction of particles with particle sizes R1≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil”;The polar deviation of the 30 obtained values ​​is the distribution uniformity of particles with a particle size R1 of R1 ≥ 1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, where the polar deviation is the difference between the maximum and minimum values ​​of the 30 values. The lower the distribution uniformity of particles with a particle size R1 of R1 ≥ 1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the more uniform the distribution of the large particles with a particle size R1 of R1 ≥ 1000 nm in the cathode film layer. This can help to reduce the phenomenon of stress concentration at the large particles in the cathode film layer, reduce the cathode film layer rebound rate and the effects on the casing and sealing zone, and improve the reliability of the battery cells.

[0130] In some embodiments, the particle distribution uniformity with a particle size R1 of R1≥1000 nm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is optionally 0.01%, 0.1%, 0.2%, 0.24%, 0.3%, 0.4%, 0.45%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 0.99%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.47%, 1.5%, 1.6%, 1.7%, 1.8%, 1.81%, 1.82%, 1.85%, 1.9%, 1.94%, 1.95%, 1.98%, 1.99%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.45%, 2.5%, 2.6%, 2.7%, 2.8%, 2.81%, 2.82%, 2.83%, 2.85%, 2.9%, 2.94%, 2.98%, 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%, 4.91%, 5% or any value in a range between any two of these values.

[0131] In some embodiments, the distribution uniformity of the particles with a particle size R1 of R1≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 0.2%-2%.

[0132] In some embodiments, the distribution uniformity of the particles with a particle size R1 of R1≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 0.2%-0.9%.

[0133] The distribution uniformity of particles with a particle size R1 of R1≥1000nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which effectively reduces the degree of stress concentration in the local area of ​​the film layer, so that the rebound stress during the cycling process of the thick-coated film layer can be distributed uniformly over the entire area of ​​the film layer, thereby reducing the rebound rate of the cathode film layer, thus reducing the probability of failure of the encapsulation structure and simultaneously improving the energy density of the battery, thereby increasing the reliability of the battery.

[0134] In some embodiments, the solvent in the electrolyte further comprises one or both of ethyl methyl carbonate (EMC) and ethylene carbonate (EC).

[0135] The type and mass of the solvent and electrolyte salt in the electrolyte can be determined by testing the electrolyte using methods known to those skilled in the art. For example, the composition of the electrolyte can be measured by liquid chromatography, UV spectrophotometry, UV-visible photometry, and the like.For example, the battery cell is disassembled, the free electrolyte is extracted from the battery cell, and the free electrolyte in the battery cell is diluted 3- to 10-fold with acetonitrile to obtain the electrolyte dilution solution to be tested using a GC-MS 3100 gas chromatograph for organic compositions; the above electrolyte dilution is added to the instrument for full-scan characterization with an inlet temperature of 250°C and a scan range of 35 µm to 270 µm, and the test is completed to obtain the total ion flux chromatograms of each organic compound; the corresponding organic compounds are compared according to the peak position of the chromatogram, and the corresponding percentage of each organic compound is calculated according to the peak area.For example, the content of inorganic substances in the electrolyte can be checked using an ion chromatograph (IC) by weighing out a quantitative amount of the electrolyte (the dilution concentration is in the middle of the standard curve) and setting the volume to 100 ml with ultrapure water, automatically injecting and detecting the ion chromatography, testing the ion chromatography of the inorganic substances and comparing the corresponding types of inorganic substances based on the peak positions of the chromatograms.

[0136] In some embodiments, the percentage by mass of ethyl methyl carbonate (EMC) is 39%-49% of the total mass of the electrolyte.

[0137] In some embodiments, the percentage by mass of ethyl methyl carbonate (EMC) relative to the total mass of the electrolyte is optionally 39%, 40%, 40.3%, 41%, 42%, 43%, 43.3%, 44%, 45%, 46%, 47%, 47.3%, 48%, 49% or any value in a range between two of these values.

[0138] The viscosity of ethyl methyl carbonate (EMC) is 0.65 mPa-s at 25°C, which is higher than that of DMC but lower than that of EC. It maintains good mobility even at low temperatures and, together with DMC, reduces the overall viscosity of the electrolyte, thus improving the transfer rate of lithium ions in the electrolyte and reducing Joule heating. Furthermore, EMC has higher oxidative and thermal stability compared to DMC, which further reduces gas generation during electrolyte decomposition and improves the reliability of the battery cell.

[0139] In some embodiments, the percentage by mass of ethylene carbonate (EC) is 13%-22%, based on the total mass of the electrolyte.

[0140] In some embodiments, the percentage by mass of ethylene carbonate (EC) relative to the total mass of the electrolyte is optionally 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22% or any value in a range between two of these values.

[0141] Ethylene carbonate (EC) has a very high dielectric constant, which can effectively dissolve lithium salts, improve the ionic conductivity of the electrolyte and ensure the smooth transfer of lithium ions. Furthermore, EC in the above range of mass fraction can decompose and form a stable SEI film on the surface of the active anode material, reducing side reactions and improving cycle lifetime.

[0142] In some embodiments, based on the total mass of the electrolyte, the total percentage by mass of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) is 52%-71%.

[0143] In some embodiments, the total percentage by mass of ethyl methyl carbonate (EMC) and ethylene carbonate (EC), based on the total mass of the electrolyte, is optionally 52%, 53%, 54%, 54.66%, 55%, 56%, 57%, 58%, 59%, 60%, 60.66%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 68.66%, 69%, 70%, 71% or any value in a range between any two of these values.

[0144] The total mass content of EC and EMC lies within the above range, which can complement each other to overcome the problems of the higher viscosity of EC and the poorer thermal stability and mechanical strength of the SEI film formed by EMC, in order to optimize the performance of the electrolyte and to further reduce the pressure of Joule heating and gas generation through the decomposition of the SEI film on the sealing zone from the direction of optimizing ionic conductivity and the SEI film.

[0145] In some embodiments, the electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6) and the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / L - 1.2 mol / L.

[0146] In some embodiments, the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / L, 0.95 mol / L, 1.0 mol / L, 1.05 mol / L, 1.1 mol / L, 1.15 mol / L, 1.2 mol / L or any value in a range between two of these values.

[0147] Lithium hexafluorophosphate (LiPF6) is highly soluble in carbonate ester solvents and forms a high electrolyte concentration to ensure high ionic conductivity of the lithium ions in the electrolyte and to induce the formation of a stable SEI film at the low-potential anode, thus reducing lithium deposition and improving cycle lifetime. If the lithium hexafluorophosphate concentration is too high, the viscosity of the electrolyte increases significantly, restricting lithium ion diffusion and decreasing ionic conductivity. Meanwhile, the decomposition products of lithium hexafluorophosphate, including PF5, react with trace amounts of water in the electrolyte to generate RF, which corrodes the electrodes and SEI films and exacerbates solvent decomposition for gas generation.The concentration of lithium hexafluorophosphate in the above range can achieve the best balance in terms of ionic conductivity and electrolyte stability.

[0148] In some embodiments, the percentage by mass of dimethyl carbonate is 18%-26%, based on the total mass of the electrolyte.

[0149] The mass fraction of dimethyl carbonate is within the above range, and the introduction of EC and EMC with a larger proportion further reduces the ability and probability of gas generation and improves the long-term reliability of the battery cell.

[0150] In some embodiments, the electrolyte further comprises vinylidene carbonate (VC), wherein the percentage by mass of ethylene carbonate (EC) is 0.5%-1.5%, based on the total mass of the electrolyte.

[0151] The vinylidene carbonate undergoes a reduction reaction at the anode surface, which is preferential to other solvent components, to generate a dense SEI film rich in organolithium compounds. This SEI film exhibits high lithium-ion conductivity, contributing to improved kinetic performance of the battery cell. Furthermore, the SEI film displays high mechanical strength and chemical stability, preventing continuous electrolyte degradation and thus reducing the consumption of active lithium and gas generation from side reactions.

[0152] In some embodiments, the median is C 50 of the degree of graphitization in the cumulative distribution curve for the graphitization C value of the cathode film layer obtained in the area-scanning mode of the laser microconfocal Raman spectrometer, 0.95–1.20; where the graphitization C value I G / I D is, where IG for the intensity of the G-peak of the Raman spectrum at 1580±100cm -1 and I D for the intensity of the D-peak of the Raman spectrum at 1350±100cm -1 stands.

[0153] In the present application, the graphitization C-value can be obtained by an area-scanning mode of the laser microconfocal Raman spectrometer. As an example, a laser microconfocal Raman spectrometer (a high-precision Renishaw laser microconfocal Raman spectrometer) is used, an excitation wavelength of 532 nm is selected, and a suitable amount of the cathode film layer is taken for area scanning of the surface or a cross-sectional area along the thickness direction of the electrode foil. The scanning area is 45 µm × 45 µm, subdivided into 10 × 10 grids, with the vertex of the grid serving as the test point. The step size is 5 µm, and the total number of scan points is 100 to obtain the C-values ​​at various locations and the cumulative distribution curve of the C-values ​​in the area-scanning area.

[0154] The cathode film layer in the present application can be either a freshly produced cathode film layer or a cathode film layer obtained by dismantling a battery. The surface of the cathode film layer obtained by dismantling the battery inevitably contains residues of electrolyte salt particles, and to improve the accuracy of the test, an area scan of a cross-sectional area of ​​the cathode film layer is preferably carried out along the thickness direction of the electrode foil to characterize the degree of graphitization of the cathode film layer.

[0155] The graphitization C value of the cathode film layer is obtained from the peak intensity ratio of the G-peak (G-band) and the D-peak (D-band) of the Raman spectra, with the position of the G-peak at 1580±100cm -1 lies and the sp 2-Hybrid structure of carbon is characterized, and the position of the D-peak is at 1350±100cm -1 lies and characterizes the disordered structure, where disorder means that there is no regular arrangement between the carbon atoms in the structure. In graphite crystals, the carbon atoms in the same layer are sp 2 -hybridized and form covalent bonds, with van der Waals forces acting between the layers, allowing the carbon to slide easily within the graphite structure. Therefore, the C value can characterize the degree of graphitization of the cathode film layer. It is important to understand that the degree of graphitization in the cathode film layer is primarily due to the graphitized carbon material within the cathode film layer, i.e., the carbon material on the surface of the active cathode material. Although conductive materials such as carbon nanotubes, which are rich in sp 2-hybridized structures are also relatively high I G / I D Despite exhibiting values, their incorporation into the cathode film layer proves to be an extreme value in the Raman area scanning test of the cathode film layer due to their low additive content and small tube diameters, and they have no influence on the degree of graphitization C. 50 in the cathode film layer. Therefore, the degree of graphitization of the cathode film layer can also characterize the degree of graphitization of the active cathode material.

[0156] The cumulative distribution curve of graphitization degree-C value is the curve obtained when at least 100 C values ​​are arranged in order from smallest to largest, using the graphitization degree as the horizontal axis and the cumulative number of values ​​as the vertical axis. 50The C-value is determined when the cumulative number fraction on the vertical axis of the curve of the cumulative distribution of graphitization degree-C-value is 50%. The median C 50 The degree of graphitization, compared to a point value, can reflect the degree of graphitization of the particles in the cathode film layer, i.e., the degree of ease of particle sliding; and compared to a mean value, it can reduce the influence of extreme values ​​in the test process and improve the reliability of the test results.

[0157] A person skilled in the art can regulate the degree of graphitization of the active material particles using any known method. For example, the degree of graphitization of the active material particles can be adjusted by regulating the carbon source, the sintering temperature, the sintering time, the sintering pressure, and the sintering atmosphere. The higher the degree of graphitization of the carbon on the surface of the active cathode material, the higher the proportion of graphitic structural carbon in the cathode film layer, and the more easily the particles can slide on the surface of the active material particles with the aid of the highly graphitized carbon structure, thus reducing the stress concentration in the electrode foil.

[0158] In some embodiments, the median is C 50of the graphitization degree in the cumulative distribution curve for the graphitization C value of the cathode film layer optionally 0.95, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20 or any value in a range between two of these values.

[0159] Research has shown that the stress on the film layer during cyclic expansion most likely leads to an increase in internal mechanical pressure, causing the encapsulation structure to fail. By controlling the median C 50The graphitization degree in the cumulative distribution curve for the graphitization C value of the cathode film layer, obtained in the area scanning mode of the laser microconfocal Raman spectrometer, is 0.95-1.20. This improves the graphitization degree of the cathode film layer, the degree of particle slippage in the cathode film layer, the phenomenon of stress concentration during the pressing process of the thickly coated film layer, and the degree of cathode film layer rebound during the cycle process due to local stress concentration. This increases the reliability of the battery cell while improving the volume energy density of the battery cell.

[0160] In some embodiments, the median B 50of the coating value in the cumulative distribution curve for the coating value-B of the cathode film layer, obtained in the area scanning mode of the laser microconfocal Raman spectrometer, 0.30-0.60; where the coating value-B I P / I D is, where I P for the intensity of the P-peak of the Raman spectrum at 948±100cm -1 and I D for the intensity of the D-peak of the Raman spectrum at 1350±100cm -1 stands.

[0161] In the present application, the coating value B can be obtained by an area-scanning mode of the laser microconfocal Raman spectrometer. As an example, a laser microconfocal Raman spectrometer (a high-precision Renishaw laser microconfocal Raman spectrometer) is used, an excitation wavelength of 532 nm is selected, and a suitable amount of the cathode film layer is taken for area scanning of the surface or a cross-sectional area along the thickness direction of the electrode foil. The scanning area is 45 µm × 45 µm, subdivided into 10 × 10 grids, with the vertex of the grid serving as the test point. The step size is 5 µm, and the total number of scan points is 100 to obtain the B values ​​at various locations and the cumulative distribution curve of the B values ​​in the area-scanning area.

[0162] The coating value B of the cathode film layer is obtained from the peak intensity ratio of the P-peak (P-band) and the D-peak (D-band) of the Raman spectra, with the position of the P-peak at 948±100cm -1 lies and the phosphate PO4 3- -structure characterized, and where the position of the D-peak is at 1350±100cm -1 The Raman spectrum is characterized by its disordered structure, where disorder means there is no regular arrangement between the carbon atoms in the structure. The Raman spectrum is a surface analyzer, so the carbon structure peaks of the cathode film layer exhibit higher intensity in the area-scanning mode of the laser microconfocal Raman spectrometer compared to the phosphate structure peaks, which are more prevalent in the bulk phase.

[0163] A person skilled in the art can regulate the coating value of the active material particles using any known method. For example, the coating value of the active material particles can be adjusted by regulating the type of carbon source, the amount of carbon source added, the sintering temperature, the sintering time, the sintering pressure, and the sintering atmosphere. The coating value B can reflect the degree of density of the carbon material on the surface of the lithium-containing transition metal phosphate particles. The denser the carbon material, the relatively lower the intensity of the phosphate structure detected in the Raman spectrum, and the lower the coating value B of the cathode film layer.

[0164] The cumulative distribution curve of coating value B is the curve obtained when at least 100 B values ​​are arranged in order from smallest to largest, using the coating value as the horizontal axis and the cumulative number of values ​​as the vertical axis. 50 The B-value is the value when the cumulative number fraction of the vertical axis in the curve of the cumulative distribution of coating value-B is 50%.

[0165] In some embodiments, the median B 50 of the coating value in the cumulative distribution curve for the coating value-B of the cathode film layer optionally 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.355, 0.36, 0.368, 0.369, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.446, 0.45, 0.456, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6 or any other value Value in a range between two of these values.

[0166] To reduce the influence of the extreme value of the coating value due to the non-particle-like region in the cathode film layer on the test results, the median B was 50 The coating value is used to assess the degree of density of the carbon material on the surface of the active cathode material.

[0167] The median B 50 The coating value of the cathode film layer lies within the above range, indicating that the carbon material on the surface of the active cathode material is relatively dense and uniform, which contributes to improving the uniformity of cathode film layer slippage during roller pressing, reducing the phenomenon of stress concentration in the cathode film layer, reducing the degree of cathode foil rebound, and increasing the reliability of the battery cell.

[0168] In some embodiments, the lithium-containing transition metal phosphate particles include iron elements, with the iron dissolution rate of the cathode film layer being 658 ppm-1921 ppm, optionally 658 ppm-1485 ppm.

[0169] The iron dissolution rate of the cathode film layer can be tested as follows. Specifically, the electrode foil is removed from the battery, washed, and then placed in a small disk with a diameter of 14 mm. Numerous small disk samples are taken, so that the total mass of the samples is approximately 5 g. These are added to 100.3 g of a 0.3% mass concentration ascorbic acid solution (the solvent being high-purity water). The solution is stirred at 500 revolutions per minute for 5 minutes, then rapidly aspirated with a 5 mL syringe and filtered into a test tube using a 0.45 µm orifice filter. Using a pipette gun, 1 mL of the supernatant is aspirated and placed in a glass volumetric flask for 50-fold dilution. The iron dissolution rate is then tested using an inductively coupled plasma mass spectrometer (ICP-OES).To obtain the concentration of iron element in the solution using the following formula: [(ICP test concentration of iron element × volume of solution / mass of solution used for analysis) × 100.3 g / (mass of electrode foil of small disk - mass of collector of small disk)], where the volume of the solution is 50 mL and the mass of the solution used for analysis is 1 g, the iron dissolution rate of the cathode film layer is calculated. Preferably, the collector mass of the small disk is obtained by multiplying the thickness of the small disk by the area and by the density. The thickness of the small disk can be determined by measuring the thickness of the collector in the uncoated area using a thickness gauge. Although the collector in the coated area expands during compaction, resulting in a slight reduction in thickness compared to the uncoated area,This has no undue impact on the test results, as the reduction is negligible.

[0170] In some embodiments, the lithium-containing transition metal phosphate particles include iron, and the iron dissolution rate of the cathode film layer is optionally 658 ppm, 700 ppm, 800 ppm, 890 ppm, 900 ppm, 1000 ppm, 1058 ppm, 1076 ppm, 1100 ppm, 1143 ppm, 1200 ppm, 1236 ppm, 1300 ppm, 1311 ppm, 1384 ppm, 1349 ppm, 1400 ppm, 1485 ppm, 1500 ppm, 1531 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1921 ppm, or any value in a range between any two of these values.

[0171] The iron dissolved in the cathode film layer originates primarily from the lithium-containing transition metal phosphate of the active cathode material. The iron dissolution rate depends on both the number of lattice defects in the lithium-containing transition metal phosphate and the completeness and density of the carbon material on the surface of the active cathode material. The lower the iron dissolution rate, the fewer the lattice defects in the lithium-containing transition metal phosphate, which reduces lattice corrosion in the weakly acidic environment. Conversely, the more complete and dense the carbon material on the surface of the active cathode material, which inhibits the dissolution of iron ions in the weakly acidic environment.The cathode film layer with an iron dissolution rate within the above range exhibits relatively few lattice defects, and the carbon material on the surface of the active cathode material is complete and dense, which is conducive to improving the compression resistance and the degree of easy particle slippage in the cathode film layer under high rolling pressure, increasing the compression density of the cathode film layer and reducing the stress concentration in the cathode film layer, thus improving the energy density of the battery and improving the reliability of the battery.

[0172] In some embodiments, the cathode film layer further comprises a conductive agent, wherein, with respect to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the proportion of the total area of ​​an agglomeration region of the conductive agent is 0.5%-2.5%.

[0173] In the present application, the area fraction of the conductive agglomeration region can be tested by the following method, based on the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil. The area of ​​the conductive agglomeration region in this scanning electron microscope image is measured at a magnification of 3k by scanning the cross-sectional area of ​​the cathode film layer using a scanning electron microscope according to a similar method described above. Since the conductive material is generally carbon-based, such as conductive carbon black, carbon nanotubes, etc., the agglomerated conductive material is visible at high magnification, and the conductive agglomeration region tends to show a black agglomeration compared to other areas in the cathode film layer.Using image analysis software, the conductive agglomeration area is the black area where the conductive material is clearly aggregated in the scanning electron microscopy image. Specifically, the scanning electron microscopy image is imported into ImageJ at a magnification of 3k, the black agglomeration areas of the conductive material with a feret of 2 µm or more are filtered out, and the sum of the areas of the filtered-out areas is statistically recorded as the area of ​​the conductive agglomeration area. The area fraction of the conductive agglomeration area is the ratio of the area of ​​the conductive agglomeration area to the total area of ​​the imported scanning electron microscopy image.Three scanning electron microscope images with non-overlapping areas are taken at random, the average value of the area fractions of the agglomeration area of ​​the conductive medium is calculated and averaged as "the area fraction of the agglomeration area of ​​the conductive medium relative to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil".

[0174] In some embodiments, the proportion of the total area of ​​an agglomeration region of the conductive medium, relative to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, is optionally 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.68%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.41%, 2.5%, or any value in a range between two of these values.

[0175] Based on the total cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the proportion of the total area of ​​the agglomeration zone of the conductive medium is 0.5%-2.5%, which indicates that the conductive medium is uniformly dispersed in the cathode film layer and it is easy to form a homogeneous conductive network, which particularly helps to reduce the problem of reduced kinetics in a thick-coated film layer due to the increase in ion transfer paths, and to reduce local polarization or even lithium precipitation of the battery during the cycling process.

[0176] At the same time, research has shown that the lithium-containing transition metal phosphate particles in the large particle size are easily rebounded; the agglomeration area of ​​the conductive agent in the above area may be able to inhibit the rebound of the lithium-containing transition metal phosphate by means of the uniform distribution of the conductive agent in order to form a mechanical bond of the particles and even of the film layer, improve the cohesion of the film layer, reduce the probability of failure of the sealing area and improve the reliability of the battery.

[0177] In some embodiments, the cathode film layer further comprises a conductive agent, wherein, with respect to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the area fraction of an agglomeration region of the conductive agent is 0.5%-1.7%.

[0178] In the embodiments of the present application, the area fraction of the agglomeration region of the conductive agent lies further within the above range, indicating that the conductive agent is distributed more uniformly in the cathode film layer and that the content of the conductive agent is lower, which improves the kinetic performance of the cathode film layer and at the same time helps to reduce the occupancy of the space of the active cathode material due to the excess of conductive agent, thus further improving the volume energy density of the battery and simultaneously increasing the kinetic performance of the battery.

[0179] In some embodiments, the conductive medium comprises carbon nanotubes, wherein the carbon nanotubes comprise one or more of single-walled carbon nanotubes, thin-walled carbon nanotubes, or multi-walled carbon nanotubes.

[0180] In the present application, the term "carbon nanotube" refers to a nanomaterial with several to ten layers of coaxial hollow tubes formed by rolling up graphene layers with sp 2 Carbon nanotubes are formed by hybridization of carbon atoms bonded to graphene. Their diameters typically range from a few to several dozen nanometers, and their lengths can vary from micrometers to centimeters, exhibiting a high length-to-diameter ratio. Carbon nanotubes can be classified according to the number of graphene layers: single-walled carbon nanotubes (SWCNTs), few-walled carbon nanotubes (FWCNTs), and multi-walled carbon nanotubes (MWCNTs). Carbon nanotubes possess excellent electrical conductivity and a high modulus of elasticity.

[0181] Due to the structural properties of carbon nanotubes with a high length-to-diameter ratio, it is advantageous to overlap multiple cathode particles and particles in the thickness direction to form a long-range conductive path and simultaneously improve the bonding force between the particles. This not only contributes to improving the kinetic performance of the thick-coated cathode film layer, but also to reducing local polarization and even lithium precipitation problems that arise during the battery cycling process, thus improving the battery cycle life. It can also be used as a bridge for voltage propagation, as it is capable of forming a network structure in the cathode film layer, effectively reducing voltage concentration, decreasing the degree of electrode foil rebound, and improving the reliability of the battery cell.

[0182] Simultaneously, carbon nanotubes possess a high specific surface area and a hollow structure, resulting in excellent fluid retention capacity. The extensibility of the thick electrode film during the cycling process is significant, facilitating easy electrolyte extrusion. Carbon nanotubes in the cathode film layer contribute to improving the fluid retention capacity of the thick electrode film, mitigating the phenomenon of capacity degradation during the battery cell's cycling process, and extending the battery cell's cycle life.

[0183] In some embodiments, the conductive medium also comprises conductive carbon black.

[0184] Conductive carbon black has a high specific surface area and therefore good liquid retention capacity. The expansion force of the thick electrode foil during the cycling process is high, which allows the electrolyte to be easily extruded. The distribution of conductive carbon black in the cathode film layer helps to improve the liquid retention capacity of the thick electrode foil, mitigate the phenomenon of capacity loss during the battery's cycling process, and improve the battery's cycle life.

[0185] In some embodiments, the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black.

[0186] The researchers found that carbon nanotubes, due to their high surface energy, tend to agglomerate, leading to an uneven distribution in the cathode film layer and preventing the formation of an effective network structure of carbon nanotubes. Conductive carbon black, with a surface energy close to that of carbon nanotubes, can be adsorbed onto their surface to form a physical barrier. This increases resistance to agglomeration, reduces direct contact between the carbon nanotubes, and thus inhibits the agglomeration phenomenon, thereby improving the uniformity of carbon nanotube distribution within the cathode film layer.On the one hand, this helps to improve the electrical conductivity of the thick-coated cathode film layer and the kinetic performance of the battery; on the other hand, it helps to exert the binding effect of the carbon nanotubes on the cathode film layer, reducing the risk of the thick-coated cathode film layer delaminating and further improving the kinetic performance and lifetime of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive agent also leads to the blocking of the local ion transfer pathway in this region, and the collocation of conductive carbon black can improve the lithium-ion transfer capacity in this region, reduce local polarization, and further improve the cycle stability of the battery.

[0187] In some embodiments, the mass fraction C1 of the carbon nanotubes fulfills 0 with respect to the mass of the cathode film layer. <C1≤2,5% und der Massengehalt C2 des leitfähigen Rußes 0<C1≤2,5%.

[0188] In some embodiments, the mass fraction C1 of the carbon nanotubes, based on the mass of the cathode film layer, is optionally 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.67%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% or any value in a range between two of these values.

[0189] In some embodiments, the mass fraction C2 of the conductive carbon black, based on the mass of the cathode film layer, is optionally 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% or any value in a range between two of these values.

[0190] The mass content of carbon nanotubes and conductive carbon black in the cathode film layer within the above range can effectively reduce the agglomeration phenomenon of the carbon nanotubes and form a good conductive network structure, thereby effectively reducing the rebound of the densely coated cathode film layer and improving the reliability of the battery cell; improving the retention rate of electrolyte solution of the cathode film during long cycles, thereby reducing the degree of polarization and improving the capacity of the battery cell.

[0191] In some embodiments, the cathode film layer further comprises a dispersing agent, wherein the dispersing agent comprises hydrogenated nitrile butadiene rubber HNBR.

[0192] HNBR is obtained from nitrile rubber by hydrogenation of saturated double bonds, and its highly saturated main-chain structure gives it excellent oil resistance, heat resistance, and aging resistance, among other properties. This makes it stable in various environments and systems when used as a dispersant, and it does not degrade or degrade easily, allowing it to effectively perform the role of a dispersion agent. The HNBR molecular chain contains both polar nitrile groups and nonpolar hydrocarbon chain segments. The polar nitrile group can interact with the hydroxyl group (-OH) or the metal oxide sites on the surface of the lithium-containing transition metal phosphate particles (e.g., in lithium-containing phosphate groups).Hydrogen bonding, dipole effect) to improve particle compatibility with the solvent and reduce interfacial tension between the particles and the solvent, especially interfacial tension for large particles. In this way, the particles can be dispersed more easily and uniformly, thereby reducing aggregation due to hydrophobicity, improving the dispersion of large particles in the cathode film layer, and reducing the stress concentration caused by rebound. The nonpolar hydrocarbon chain segments, on the other hand, have good lipophilicity and can be readily stretched and dispersed in nonpolar or weakly polar media, so that the particles are uniformly dispersed in the media.

[0193] When HNBR is adsorbed onto the surface of particles in the slurry, its long-chain molecules form a physical barrier around the particles, preventing them from approaching and aggregating. This allows the particles to remain relatively independent and dispersed within the system. Simultaneously, HNBR can reduce the surface tension between the dispersion medium and the dispersed particles, making it easier for the particles to be moistened by the medium. This promotes particle dispersion, and it can also reduce the interfacial energy between the particles. This, in particular, reduces the aggregation of the conductive medium due to interfacial energy-driven phenomena and improves the cycle life of the battery cell.

[0194] In some embodiments, the mass content of the dispersant is 0.5%-2%, based on the mass of the cathode film layer.

[0195] In some embodiments, the mass fraction of the dispersant, based on the mass of the cathode film layer, is optionally 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2% or any value in a range between two of these values.

[0196] The mass fraction of the dispersant is within the above range, which allows for a uniform dispersion of the particles in the cathode film layer, while maintaining a high charge capacity of the cathode film layer, and slows down the rebound caused by the voltage concentration in the thickly coated cathode film layer of the lithium-containing transition metal phosphate, thereby reducing the rebound rate of the cathode film layer and improving the reliability of the battery cell.

[0197] In some embodiments, the porosity of the cathode film layer is 14%-28%.

[0198] In the present application, the porosity of the cathode film layer can be tested using the following procedure: Import the scanning electron micrograph of the cross-sectional area of ​​the cathode film layer, obtained using the above method, along the thickness direction of the electrode foil into the ImageJ software, select the straight line tool, use a straight line to mark the length of the scale in the image, click on "Analyze Set Scale" and adjust the scale parameters in the software according to the length of the scale in the image.Select the rectangle tool, select the portion of the image outside the scale range, use "Image Duplicate" to duplicate the selected area, use "Image Type 8 bit" to adjust the image format; select "Analyze Set Measurements" and select the following five options: "Area", "Mean gray value", "Area Fraction", "Limit to threshold", "Feret's diameter", selecting 3 for "Decimal places", and successively selecting "Imagc" - "Adjust" - "Threshold", and successively setting the "Threshold" position to 0 and 100, thereby enabling the "Analyze-Measure" function to export the pore data in the scanning electron microscope image of the section surface.Use “Image” - “Overlay” - “Flatten” to export and obtain the pore image; click “Apply” in “Threshold”, then click “Analyze” - “Analyze Particles”, checking the four columns on the left to obtain the pore statistics.

[0199] It is understood that, in an embodiment of the present application, the "pores" in the cross-sectional area of ​​the cathode film layer are identified by the color difference and the threshold of the image. The "pore" is not the porosity data obtained in the exhaust gas test, but is primarily used to characterize the cross-sectional area between the particles in the cross-sectional area of ​​the cathode film layer. This method is superior to the exhaust gas method because the porosity obtained by the exhaust gas method is related to the pores between the particles and also to the pores in the carbon material on the surface of the lithium iron phosphate particles, and therefore the pores between the particles cannot be objectively represented.

[0200] The porosity of the cathode film layer lies within the above range, which is beneficial for improving the electrolyte fluid retention properties, enhancing the ion diffusion capacity of the thickly coated electrode foil and cathode film layer, and also improving the battery's kinetic performance. Furthermore, it can cushion volume expansion during rebound or charge / discharge, reduce the effects of expansion stress on the sealing zone, and maintain the battery's high reliability.

[0201] In some embodiments, the porosity of the cathode film layer is optionally 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28% or any value in a range between two of these values.

[0202] In some embodiments, such as in Fig.As shown in Figure 2, the battery cell further comprises a separator 20 arranged between the cathode foil and the anode foil, the separator 20 comprising a base film 201 and a ceramic layer 202 provided on both sides of the base film 201, and a binder layer 203 provided on at least one of the sides of the ceramic layer 202 facing away from the base film 201, the binder layer 203 being a continuous layer with a porous structure, the binder layer 203 comprising a vinylidene fluoride polymer.

[0203] In some embodiments, the vinylidene fluoride polymer comprises one or more of the following materials: polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).

[0204] In some embodiments, the vinylidene fluoride polymer comprises polyvinylidene fluoride (PVDF).

[0205] As in Fig.As shown in Figure 3, aqueous PVDF is often used for the separator bonding layer according to the prior art, which tends to form an island-like structure in the separator, which on the one hand helps to create a gap for the expansion of the electrical core, and on the other hand is easy to produce; however, such a separator bonding layer has a smaller contact area with the electrode foil and a weak bonding force.

[0206] The separator provided by the embodiments of the present application has a continuous layer with a porous structure as a bonding layer, as shown in Fig.Figure 2 shows a larger bonding area with the electrode foil compared to the bonding layer in the prior art, resulting in a stronger and more uniform bond between the separator and the electrode foil; furthermore, if the cathode film layer detaches, it is advantageous to maintain the interfacial contact between the separator and the cathode film layer, thereby reducing the likelihood of the film layer detaching.

[0207] It is understood that the continuous layer may be broken and deformed into a block shape due to contact with the cathode foil or the anode foil, or due to extrusion by force during the manufacturing or cycling process of the electrode foil. The continuous layer referred to in the present application does not require the bonding layer to be continuous throughout the entire battery. The continuous structure in the present application is shown at the microscopic level; as can be seen under a scanning electron microscope or a light microscope, the separator bonding layer is continuous. To obtain feedback on the actual morphology of the separator, sampling preferably involves sampling the separator in an area of ​​the battery where there is no bond between the separator bonding layer and the cathode foil or the anode foil.For example, by sampling the separator at a point extending beyond the cathode and anode foils, or by sampling the separator near the surface of the electrode assembly. This type of separator exhibits less bonding between the sampling area and the cathode or anode foil, providing better feedback on the actual condition of the separator.

[0208] The separator provided by the embodiments of the present application uses a continuous layer with a porous structure as a bonding layer, which has a larger bonding area than the bonding layer in the prior art, thereby making the bond between the separator and the cathode film layer stronger and more uniform; the particles with a particle size R1 of R1≥1000 nm are susceptible to the problem of rebound due to stress concentration during the cycling process.The separator provided by the embodiments of the present application uses a continuous layer with a porous structure as a bonding layer, which is particularly suitable for the thick-coated stacked electrical core. This improves the rebound of the thick-coated stacked electrical core during long cycles and reduces the expansion stress within the battery, thereby enhancing the reliability of the sealing zone and the battery cell as a whole. Furthermore, during the pulling of the outer electrode foil and the welding of the electrode tab, a relative displacement of the thick-coated core occurs between the electrode foil and the separator. This causes the film layer to be prone to powder deposition and can even lead to overlapping of the cathode and anode, creating a risk of internal short circuits.The continuous layer with a porous structure as a binder layer in the embodiments of the present application also reduces the aforementioned risk.

[0209] In some embodiments, the material of the base film may include, but is not limited to, one or more of the following materials: fiberglass, nonwoven fabric, polyethylene (PE), polypropylene (PP).

[0210] In some embodiments, the ceramic layer comprises one or more of the following materials: aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium oxide (TiO2), silicon oxide (SiO2), boron nitride (BN).

[0211] Ceramic particles are highly flame-resistant, exhibit high hardness, and are not easily deformed by heat, resulting in excellent dimensional stability. The low thermal conductivity of ceramic materials can also prevent specific points of thermal runaway within the battery from developing into a full-blown thermal runaway, thus improving the battery cell's safety performance.

[0212] In some embodiments, the cathode film layer is provided with a lower coating layer at a lower region facing the cathode collector, the lower coating layer comprising a conductive agent and a binder, wherein the conductive agent comprises carbon nanotubes and conductive carbon black, and wherein the binder comprises a vinylidene fluoride polymer.

[0213] In some embodiments, the cathode film layer is provided with a lower coating layer on a lower area facing the cathode collector; the thickness of the lower coating layer is 0.5 µm-5 µm.

[0214] In some embodiments, the thickness of the lower coating layer is 0.5 µm, 1 µm, 1.5 µm, 2 µm, 2.5 µm, 3 µm, 3.5 µm, 4 µm, 4.5 µm, 5 µm or any value in a range between two of these values.

[0215] The lower coating layer provided in the embodiments of the present application contributes to improving the adhesion between the cathode film layer and the cathode collector and to reducing the phenomenon of voltage concentration at the large particles, thereby reducing the rebound of the cathode film layer and improving the reliability of the battery cell. At the same time, compared to direct contact between the cathode collector and the cathode film layer, the contact area between the lower coating layer and the cathode film layer is increased, which contributes to increasing the electron transfer area between the collector and the cathode film layer, thereby reducing the internal resistance of the electrode foil and improving the kinetic performance of the battery.

[0216] In some embodiments, the lithium-containing transition metal phosphate particles in the cathode film layer comprise a component with the following formula: Li m Fe x P y O j Q q Formula 1: where Q comprises one or more of Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, Cl, Br, and where 0.8≤m≤1.15, 0.9≤x≤1, 0.95≤y≤1, 3.5≤j≤4, 0≤q≤0.1.

[0217] In some embodiments, m is optionally 0.8, 0.85, 0.9, 0.95, 0.98, 1.00, 1.03, 1.05, 1.08, 1.10, 1.13, 1.15 or any value in a range between any two of these values; x is optionally 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0 or any value in a range between any two of these values; y is optionally 0.95, 0.96, 0.97, 0.98, 0.99, 1.00 or any value in a range between any two of these values; j is optionally 3.5, 3.6, 3.7, 3.8, 3.9, 4 or any value in a range between any two of these values; q is optionally 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 or any value in a range between any two of these values.

[0218] The selection of the appropriate modification element Q can improve the lattice change rate of the active cathode material in the process of de-embedded lithium, reduce the oxygen activity on the surface of the particles, improve the structural stability of the material and thereby improve the level of the gram capacity play of the material during the cycle and improve the cycle stability of the battery cell.

[0219] In some embodiments, the lithium-containing transition metal phosphate particles comprise titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of titanium is 500 ppm-8000 ppm, optionally 1000 ppm-3000 ppm.

[0220] Both the type and the content of the elements in the lithium-containing transition metal phosphate particles in the cathode film layer can be tested according to any known methods in the relevant technical field. For example, the titanium content is tested using inductively coupled plasma emission spectrometry with reference to Annex C of GB / T 33822-2017.

[0221] In some embodiments, the mass fraction of titanium, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, is optionally 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1900 ppm, 2000 ppm, 2100 ppm, 2200 ppm, 2300 ppm, 2400 ppm, 2500 ppm, 2600 ppm, 2700 ppm, 2800 ppm, 2900 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm. 5000ppm, 5500ppm, 6000ppm, 6500ppm, 7000ppm, 7500ppm, 8000ppm or any value in a range between any two of these values.

[0222] The introduction of titanium into lithium-containing transition metal phosphate particles requires the addition of a titanium source during the fabrication of the active cathode material. This titanium source is often an inert material that adheres to the surface of the lithium-containing transition metal phosphate to reduce reactivity and particle size growth. Increasing the degree of graphitization of the active cathode material often necessitates a higher sintering temperature or a longer sintering time, which, however, also increases the particle size in the cathode film layer, raises the stress concentration in the cathode film layer, and triggers the phenomenon of cathode film delamination.In the embodiments of the present application, the reactivity of the synthetic raw material of the active cathode material can be reduced by adding a high proportion of titanium to the lithium-containing transition metal phosphate particles, so that the active cathode material has a high degree of graphitization and at the same time achieves control of the proportion of large particles, reduces the rebound rate of the cathode film layer and improves the energy density of the battery, taking into account the reliability of the battery.

[0223] Simultaneously, the doping of titanium in the active cathode material leads to lattice distortion, reduces the Li-O bond energy, increases the lithium ion diffusion rate, and improves the battery's kinetic performance. The uneven diffusion of lithium ions in the thick-coated film layer is often accompanied by significant lithium ion concentration gradients, and the embodiments of the present application improve the solid-state transfer rate of the active cathode material by adding a high titanium content to the lithium-containing transition metal phosphate particles, thereby improving the kinetics of the battery with a thick electrode film.

[0224] In some embodiments, the lithium-containing transition metal phosphate particles comprise vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of vanadium is 500 ppm-5000 ppm, optionally 500 ppm-3000 ppm.

[0225] In some embodiments, the mass content of vanadium, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, is optionally 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1900 ppm, 2000 ppm, 2100 ppm, 2200 ppm, 2300 ppm, 2400 ppm, 2500 ppm, 2600 ppm, 2700 ppm, 2800 ppm, 2900 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm. 5000ppm or any value in a range between two of these values.

[0226] The vanadium element in the cathode film layer can exist in different valence states, with +5-valent vanadium (V5+ ) can be doped with phosphorus sites, which, due to its larger radius, leads to lattice distortions, thus enlarging the lithium-ion diffusion channels and thereby improving the ionic conductivity of the active cathode material, thus improving the kinetic performance of the battery; whereas +3-valent vanadium (V 3+ Since the material can be doped with transition metal sites, lithium gaps are created through charge compensation, thereby improving the electronic conductivity of the active cathode material. Furthermore, the increased uniformity of the vanadium element in the lithium-containing transition metal phosphate particles contributes to a further improvement in the kinetic performance and reaction uniformity of the cathode film layer, thus improving the kinetic and cycle performance of the battery cell.

[0227] The vanadium content in the above area contributes to improving the kinetic performance of the cathode foil and the kinetic performance of the thick-coated lithium-containing transition metal phosphate battery. Simultaneously, the synergistic action of the titanium element, the vanadium element, and the carbon nanotubes in the cathode film layer helps to form a good three-dimensional network, further improving the electronic and ionic conductivity of the cathode film layer, thereby further enhancing the kinetic performance of the thick-coated lithium-containing transition metal phosphate battery.

[0228] In some embodiments, the lithium-containing transition metal phosphate in the cathode film layer comprises one or more of the following materials: lithium iron phosphate, lithium manganese phosphate, lithium fluorine-substituted vanadium phosphate, lithium ferromanganese phosphate and their modified materials.

[0229] In some embodiments, the lithium-containing transition metal phosphate in the cathode film layer comprises one or the following materials: lithium iron phosphate and its doped modified materials, as well as modified coating materials.

[0230] The aforementioned lithium-containing transition metal phosphates exhibit good thermal stability, cycle stability, etc., which contributes to improving the safety performance and cycle performance of the battery.

[0231] In some embodiments, the soft packaging material comprises an aluminum-plastic composite film, optionally a composite film formed from one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE) with aluminum.

[0232] The soft packing materials are of a higher quality and lighter than hard shell materials such as aluminum and steel shells, which contributes to a further improvement in the energy density of lithium-containing transition metal phosphate batteries.

[0233] In some embodiments, at least one stacked electrical core is accommodated in the housing 50, wherein the housing has a dimension of L0 in a longitudinal direction, wherein the housing has a dimension of W0 in a width direction, wherein the housing has a dimension of H0 in a thickness direction, wherein 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm, and 14 mm ≤ H0 ≤ 22 mm.

[0234] In some embodiments, L0 is optionally 450 mm, 460 mm, 470 mm, 480 mm, 490 mm, 500 mm, 510 mm, 520 mm, 530 mm, 540 mm, 550 mm, 560 mm, 570 mm, 580 mm, 590 mm, 600 mm, 610 mm, 620 mm, 630 mm, 640 mm, 650 mm, 660 mm, 670 mm, 680 mm, 690 mm, 700 mm, 710 mm, 720 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm, 1000 mm, 1050 mm, 1100 mm, 1150 mm, 1200 mm, 1250 mm mm, 1300 mm or any value in a range between any two of these values.

[0235] In some embodiments, W0 is optionally 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm or any value in a range between any two of these values.

[0236] In some embodiments, H0 is 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm or any value in a range between any two of these values.

[0237] In some embodiments, the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 450 mm ≤ L0 ≤ 650 mm.

[0238] If the length dimension L0 of the casing meets the criteria of 450 mm ≤ L0 ≤ 650 mm, the battery cell length is shorter. This helps to shorten the current diffusion path and reduce the internal resistance of the electrodes, thereby reducing heat generation in the battery and improving its kinetic performance. Furthermore, the shorter casing length contributes to shortening the electrolyte diffusion path during the infiltration process, improving the infiltration rate and electrolyte uniformity, further promoting the uniformity of lithium ion disembedding during the cycling process, mitigating the phenomenon of voltage concentration, reducing the amplitude of the film layer rebound, and improving the reliability of the battery cell.

[0239] In some embodiments, the dimension Lo of the housing in the longitudinal direction satisfies the following condition: 900 mm ≤ L0 ≤ 1300 mm.

[0240] If the longitudinal dimension L0 of the casing meets the following condition: 900 mm ≤ L0 ≤ 1300 mm, the longer battery cell size helps to reduce the volume fraction of the casing within the battery cell and improve the load-bearing capacity of the active material. Simultaneously, a longer battery cell can reduce the number of batteries required in the battery module, simplify the structural design of the battery module, decrease the number and complexity of structural components within the module, and thereby improve the space utilization rate of the battery pack, which in turn contributes to improving the volumetric energy density of the battery cell.

[0241] In some embodiments, the battery cell capacity at 25°C is 105 Ah-300 Ah, optionally 150 Ah-190 Ah.

[0242] In the present application, the capacity of the battery cell has a meaning known in the art and can be tested by methods known in the art. For example, the battery is charged to 3.65 V at a charging rate of 0.5C of the nominal capacity of the battery, then charged to 0.05 C at a constant voltage of 3.65 V and left to stand for 10 minutes, then discharged to 2.5 V at a discharge rate of 1C and left to stand for 10 minutes, and the capacity in units of Ah is calculated during the discharge process according to the formula C=I×t.

[0243] In some embodiments, the capacity of the battery cell at 25°C can optionally be 125Ah, 130Ah, 135Ah, 140Ah, 145Ah, 150Ah, 155Ah, 160Ah, 165Ah, 170Ah, 175Ah, 180Ah, 185Ah, 190Ah, 200Ah, 210Ah, 220Ah, 230Ah, 240Ah, 250Ah, 260Ah, 270Ah, 280Ah, 290Ah, 300Ah or any value in a range between two of these values.

[0244] In some embodiments, the cathode collector can be a metal foil or a composite collector. For example, an aluminum foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0245] In some embodiments, the anode collector can be a metal foil or a composite collector. For example, a copper foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0246] In some embodiments, the anode film layer comprises an active anode material. The active anode material may, for example, comprise at least one of the following materials: synthetic graphite, natural graphite, soft carbon, or hard carbon. However, the present application is not limited to these materials, and other conventional materials suitable for use as active anode materials in batteries may also be used. It is possible to use only one of these active anode materials or to use more than two in combination.

[0247] In some embodiments, the anode film layer optionally comprises a binder. This binder may be at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0248] In some embodiments, the anode film layer further optionally comprises a conductive medium. The conductive medium can be at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene and carbon nanofibers.

[0249] In some embodiments, the anode film layer optionally includes further additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0250] In some embodiments, the anode foil can be produced as follows: Dispersing the components described above for the production of the anode foil, such as the active anode material, the conductive agent, the binder and other components, in a solvent (e.g. deionized water) to form an anode slurry; applying the anode slurry to the anode collector and obtaining the anode foil after drying, pressing and other processes.

[0251] A second aspect of the present application provides a battery device comprising a battery cell according to the first aspect of the present application.

[0252] The battery devices disclosed in the embodiments of this application can be used in power-consuming devices that use the battery devices as a power source, or in various energy storage systems that use the battery devices as an energy storage element. The battery devices can be used, among other things, for mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric vehicles, ships, spacecraft, and the like, as well as for vehicles. Electric toys can include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric boat toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0253] Furthermore, the present application provides a power-consuming device that uses the battery device as a power source, wherein the power-consuming device comprises at least one of the battery cells of the present application, a battery module, and a battery pack. The battery cell, battery module, or battery pack can be used as a power source for the power-consuming device or as an energy storage unit for the power-consuming device.

[0254] Depending on requirements, the power-consuming device can be a battery cell, a battery module or a battery pack.

[0255] Fig.Figure 4 shows an example of the power-consuming device. The power-consuming device disclosed in the embodiments of the present application can be a fuel oil vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, a supercharged vehicle, and the like. The vehicle is provided internally with a battery device. The battery device can be located on the underside, at the front, or at the rear of the vehicle. The battery device can be used to supply power to the vehicle; for example, the battery device can be used as an operating power source for the vehicle. The vehicle can further include a control unit and a motor, the control unit serving to control the battery device in order to supply power to the motor, for example, to meet the vehicle's operating energy requirements for starting, navigating, and driving.In some embodiments of the present application, the battery device can be used not only as an operating energy source for the vehicle, but also as a propulsion energy source for the vehicle, instead of or partially instead of heating oil or natural gas to provide propulsion energy for the vehicle.

[0256] The embodiments of the present application also provide an energy storage device which uses a battery device as a power source, wherein the energy storage device may be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power plant, an energy storage battery pack or a portable energy storage system. Example of implementation

[0257] The following describes exemplary embodiments of the present application. The embodiments described below are exemplary, serve to explain the present application, and cannot be construed as limiting the present application. Unless specific techniques or conditions are indicated in the exemplary embodiments, they correspond to the techniques or conditions described in the relevant literature or to the information in the product specification. The reagents or instruments used without manufacturer identification are all commercially available products. Exemplary embodiment 1(1) Production of the active cathode material

[0258] Lithium carbonate, iron phosphate, titanium dioxide, vanadium pentoxide, sucrose, glucose, and polyethylene glycol are added to deionized water and mixed in a premixing vessel, the lithium carbonate and iron phosphate being dosed so that the molar ratio of lithium to iron is 1.025:1.0, based on the total mass of the mixed raw material, the mass content of sucrose is 2%, the mass content of glucose is 4%, and the mass content of polyethylene glycol is 5%, and after uniform mixing, a mixed raw material with a solids content of 38% is obtained;

[0259] In this, the particle size Dv50 of lithium carbonate is 6 µm; the morphology of the iron phosphate particles is spherical; titanium dioxide and vanadium pentoxide are nanoparticles; the purity of sucrose is ≥98%; the moisture content of dextrose is <0.5%; and the weight-mean molecular weight of polyethylene glycol is 1500.

[0260] The mixed raw material was milled twice in a sand mill, with coarse milling for 1 hour followed by fine milling, and the temperature of the slurry was controlled to less than 40°C during the milling process to obtain the mixed slurry; the particle size Dv50 of the solid particles in the mixed slurry is 0.45 µm, and spray drying was carried out to obtain a dry precursor powder whose particle size D50 after drying is 55.55 µm.

[0261] The precursor powder was sintered in two stages at elevated temperature in a nitrogen atmosphere to obtain the active cathode material: The temperature was increased from 25°C to 450°C at a heating rate of 2°C / min (first heating stage) and held for 3 hours. The temperature was then increased from 450°C to 780°C at a heating rate of 5°C / min (second heating stage) and held for 12 hours. During the heating stage, the ventilation was greater than during the constant temperature stage (ratio 1.5:1), with a total ventilation volume of 1350 cm³. 3 / h, followed by cooling; The active cathode material of lithium iron phosphate with a carbon material on the surface of the lithium iron phosphate with a particle size Dv50 of 1.65 µm is obtained by airflow comminution, wherein, based on the total mass of the active cathode material, the mass content of Ti element is 1050 ppm and the mass content of V element is 950 ppm.

[0262] The D50 and Dv50 values ​​above refer to data obtained through the Malvern laser scattering test. (2) Production of the cathode foil:

[0263] The above active cathode material, the conductive agent, and the binder polyvinylidene fluoride are mixed in the solvent N-methylpyrrolidone in a mass ratio of 95:2:3 and then sufficiently mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. After completion of the stirring process, the cathode slurry is transferred to a coating process. The conductive agent comprises conductive carbon black and multi-walled carbon nanotubes in a mass fraction of 1:1, with the conductive carbon black having a specific surface area of ​​80 m². 2 / g and has an oil absorption value of 180 ml / 100 g and the carbon nanotubes have an average length of 20 µm, a specific surface area of ​​280 m² 2 exhibit / g.

[0264] The cathode slurry is transferred to an aluminum foil for drying and coating, and after hot pressing, an electrode foil is formed with a cathode foil having a one-sided thickness of 106 µ9m and an electrode foil with a pressing density of 2.35g / cm³. 3 The pressing density refers here to the pressing density when the battery cell is fully discharged. The coating transfer speed is 20 m / min. The hot pressing process comprises at least three hot rolling operations, with the hot rolling pressure increasing sequentially to 40 tons, 60 tons, and 80 tons, and with the hot rolling temperature being 60°C. Prior to the first entry into the hot rolling operation, the electrode foil is heated to a temperature of 40°C.

[0265] The cathode foil is cut into strips and punched into a predetermined shape, and the punched cathode foil is sorted by weight in a weighing and sorting machine and stacked in a stacking machine.

[0266] The median L R1A50 The sphericity in the cumulative distribution curve of the sphericity area of ​​particles with a particle size R1 of R1 ≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 0.689; the median C 50 The degree of graphitization of the cathode film layer is 1.009; and the median B 50The coating value B of the cathode film layer is 0.46; the iron dissolution rate of the cathode material is 974 ppm; the area fraction of the agglomeration area of ​​the conductive medium is 1.68%, based on the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil; and the porosity of the cathode film layer is 16.03%. (3) Production of the anode foil

[0267] A mixture of artificial graphite and natural graphite (mass ratio 1:1), conductive agent of conductive carbon black, binder of styrene-butadiene rubber (SBR) and thickener of sodium carboxymethylcellulose (CMC) are mixed uniformly according to the weight percentage of 96:0.5:2.0:1.5 and deionized water is added and then stirred and dispersed to obtain the anode slurry, and the anode slurry is applied to the copper foil of the base material, and then the anode foil is obtained after drying, pressing, cutting and stacking.

[0268] The anode foil is cut into strips and punched into a predetermined shape, and the punched anode foil is sorted by weight in a weighing and sorting machine and stacked in a stacking machine. (4) Separator

[0269] Polyvinylidene fluoride (PVDF) was dissolved in N-methylpyrrolidone (NMP), stirred thoroughly, and then polyethylene glycol (PEG) was added as a pore-forming agent. The mixture was stirred and mixed sufficiently to obtain the binder layer solution. This binder layer solution was applied to the base film with a ceramic coating on both sides. The PEG was dissolved by pre-evaporation at 80°C and drying at 110°C after immersion in deionized water to create a separator with a porous binder layer structure.

[0270] The thickness of the base film is 8 µm, the thickness of the ceramic layer on one side is 3 µm, and the thickness of the bonding layer on one side is 1 µm. (5) Electrolyte

[0271] In a glovebox with an argon atmosphere (H₂O < 0.1 ppm, O₂ < 0.1 ppm), the organic solvents dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC) were thoroughly mixed. Lithium hexafluorophosphate was then added to dissolve it in the organic solvent, resulting in a lithium hexafluorophosphate concentration of 1.05 mol / L. Vinylidene carbonate (VC) was then added and stirred homogeneously to obtain the electrolyte of embodiment 1. In this electrolyte, the mass fraction of dimethyl carbonate is 26%, the mass fraction of methyl ethyl carbonate is 43.3%, the mass fraction of vinyl carbonate is 17.3%, and the mass fraction of vinylidene carbonate is 0.9%. (6) Battery production

[0272] The stacking machine is used to stack the cathode foil, separator, and anode foil sequentially. The separator should be able to insulate the cathode and anode foils to form the stacked electrical core. The stacked electrical core is then coated with adhesive, which tightly encases it. After the adhesive is applied, the stacked electrical core is placed in the outer packaging, which is a flexible aluminum-plastic film. The aluminum-plastic film consists of an inner layer of polypropylene, an intermediate layer of aluminum foil, and an outer layer of nylon composite. The aluminum-plastic film outer packaging is formed and cut to the desired shape and size using a forming machine. The aluminum-plastic film is then thermally encapsulated to achieve an encapsulation tensile strength of ≥25 N / 8 mm.The batteries are vacuum-baked, rested, injected with electrolyte solution using a flat-headed needle, and encapsulated. The soft-packed batteries are then hot-pressed and cold-pressed, with the temperature during hot-pressing being 45°C, the time 2 minutes, and the pressure 90 kg / cm². 2 The temperature during cold pressing is 25°C, the time is 2 minutes, and the pressure is 90 kg / cm². 2 The battery cell is obtained after the processes of forming, vacuum extraction, edge cutting, and edge folding, with double folding being performed during the folding process. The battery cell has dimensions of 600 mm in the length direction, 125 mm in the width direction, and 20 mm in the thickness direction.

[0273] The manufacturing process of embodiments 2 to 5 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the cathode foil is adapted as follows: Example 2

[0274] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot-pressing process, the cathode foil with a one-sided cathode film thickness of 70.45 µm is obtained by hot pressing; and the cathode foil has a pressing density of 2.35 g / cm³. 3The compression density here refers to the compression density when the battery cell is fully discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness of the cathode film layer. Example 3

[0275] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot-pressing process, the cathode foil with a one-sided cathode film thickness of 91.88 µm is obtained; and the cathode foil has a pressing density of 2.36 g / cm³. 3The compression density here refers to the compression density when the battery cell is fully discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness of the cathode film layer. Example 4

[0276] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot-pressing process, the cathode foil with a one-sided cathode film thickness of 119.49 µm is obtained by hot pressing; and the cathode foil has a pressing density of 2.35 g / cm³. 3The compression density here refers to the compression density when the battery cell is fully discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness of the cathode film layer. Example 5

[0277] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot-pressing process, the cathode foil with a one-sided cathode film thickness of 96.75 µm is obtained by hot pressing; and the cathode foil has a pressing density of 2.55 g / cm³. 3The compression density here refers to the compression density when the battery cell is fully discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness of the cathode film layer.

[0278] The manufacturing process of embodiments 6 and 7 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the electrolyte is adapted as follows: Example 6

[0279] The proportion of each solvent in the electrolyte is adjusted so that, based on the total mass of the electrolyte, the mass fraction of dimethyl carbonate is 18%, the mass fraction of methyl ethyl carbonate is 47.3%, the mass fraction of vinyl carbonate is 21.3% and the mass fraction of vinylidene carbonate is 0.9%. Example 7

[0280] The proportion of each solvent in the electrolyte is adjusted so that, based on the total mass of the electrolyte, the mass fraction of dimethyl carbonate is 32%, the mass fraction of methyl ethyl carbonate is 40.3%, the mass fraction of vinyl carbonate is 14.3% and the mass fraction of vinylidene carbonate is 0.9%.

[0281] The manufacturing process of embodiments 8 to 12 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the active cathode material and for the cathode foil is adapted as follows: Example 8 (1) Lithium dihydrogen phosphate, iron oxalate, polyethylene glycol with a weight-average molecular weight of 1000, polyethylene glycol with a weight-average molecular weight of 1600, titanium dioxide, and vanadium pentoxide are mixed uniformly in methanol and ground to obtain the mixed raw material. The ratio of lithium dihydrogen phosphate to iron oxalate is determined such that the molar ratio of lithium to iron is 1.025:1.0. The particle size D10 of iron oxalate is 6.5 µm, the particle size D50 is 62 µm, the particle size D90 is 108 µm, and the mass fraction of iron in the iron oxalate is 30.5%, and the mass fraction of ferrous iron is 0.03%.

[0282] The mixed raw material was ground several times in a ball mill and demagnetized to obtain a mixed slurry. The number of milling passes and the milling process are controlled, as is the particle size D. v50 of the mixed slurry after grinding is 3.15 µm.

[0283] The mixed slurry was spray-dried to obtain a dry precursor powder material, and the appearance of the dried precursor powder material was light yellow with a uniform color.

[0284] The precursor powder material was placed in a sintering furnace and heated from 25°C to 360°C at 2°C / min under a nitrogen atmosphere and held at this temperature for 3.5 hours. It was then heated a second time to 780°C at 5°C / min and held at this temperature for 10 hours, after which it was cooled. Based on the total mass of the active cathode material, the titanium content is 1050 ppm and the vanadium content is 950 ppm.

[0285] The obtained material was crushed by an airflow crushing process with a classification frequency of 21Hz and a crushing air pressure of 0.54 MPa to obtain an active lithium iron phosphate cathode material with the carbon material on the surface.

[0286] The above D10, D50, D90 and Dv50 refer to data obtained through the Malvern laser scattering test. (2) Production of the cathode foil:

[0287] The above active cathode material, the conductive agent, and the binder polyvinylidene fluoride are mixed in the solvent N-methylpyrrolidone in a mass ratio of 95:2:3 and then sufficiently mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. After completion of the stirring process, the cathode slurry is transferred to a coating process. The stirring process comprises a pre-stirring and a main stirring, the mixing speed of the pre-stirring being lower than that of the main stirring. The pre-stirring has a rotational speed of 25 rpm and a rotational speed of 500 rpm, and the pre-stirring time is 15 minutes. The conductive agent comprises conductive carbon black and multi-walled carbon nanotubes in a mass fraction of 1:1, the conductive carbon black having a specific surface area of ​​80 m². 2 / g and has an oil absorption value of 180 ml / 100 g and the carbon nanotubes have an average length of 20 µm, a specific surface area of ​​280 m² 2 exhibit / g.

[0288] The cathode slurry is coated onto an aluminum foil for drying, and after hot pressing, a cathode foil is produced with a one-sided thickness of the cathode film layer of 106.34 µm and a pressing density of 2.35 g / cm³. 3 obtained. The compression density here refers to the compression density when the battery cell is completely discharged.

[0289] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 35 tonnes, 55 tonnes and 75 tonnes; and wherein the hot rolling temperature is 65°C, and wherein the electrode foil is heated before the first entry into the hot rolling press, and wherein the temperature of the heating is 50°C.

[0290] The cathode foil is cut into strips and punched into a predetermined shape, and the punched cathode foil is sorted by weight in a weighing and sorting machine and stacked in a stacking machine. Exemplary embodiment 9(1) Production of the active cathode material

[0291] Lithium carbonate, iron phosphate, sucrose, glucose, titanium dioxide and vanadium pentoxide are added to water and mixed in a premixing vessel at a speed of 1800 rpm, wherein the lithium carbonate and the iron phosphate are in such a ratio that the molar ratio of iron to phosphorus is 0.97, the glucose has a mass content of 3.8% compared to the iron phosphate and the sucrose has a mass content of 1.9% compared to the iron phosphate;

[0292] The mixed raw materials undergo two milling operations in a sand mill. The first milling is carried out using zirconium oxide spheres with a diameter of 0.6 mm at a speed of 500 rpm and a milling chamber pressure of less than 0.3 MPa for 1 hour. A second milling is then performed to obtain a mixed slurry, with the particle size D v50 the mixed slurry is 0.435 µm;

[0293] The mixed slurry is spray-dried to obtain a precursor powder;

[0294] The precursor powder is sintered to obtain a lithium iron phosphate cathode material, the sintering process comprising:

[0295] The first sintering: Sintering of the precursor powder in a nitrogen atmosphere, heating from 25°C to 765°C at a heating rate of 5°C / min and holding for 10 hours, and cooling to obtain a first sintered product;

[0296] Grinding and mixing: Adding 0.5% sucrose, 0.1% glucose, and 3.0% polyethylene glycol to the first sintered product; dividing into two groups for grinding (the third grinding); stopping grinding when D v50 The particle size in the first group reaches 1.02 µm (grinding conditions: 550 rpm, grinding time: 1 hour) to obtain a first-group milled product; stop grinding when D v50The particle size in the second group reaches 0.42 µm (grinding conditions: 500 rpm, grinding time: 4 hours) to obtain a second-group milled product; The first-group milled product and the second-group milled product are mixed in a mass ratio of 70:30 to obtain a mixed intermediate product; The mixed intermediate product is spray-dried;

[0297] The second sintering: Sintering of the mixed intermediate product in a nitrogen atmosphere, heating from 25°C to 800°C at a heating rate of 5°C / min and holding for 10 hours, and cooling to obtain a second sintered product.

[0298] After sintering is complete, the product is cooled to below 100 °C. The second sintered product is then crushed using an airflow process to obtain the active cathode material, consisting of lithium iron phosphate with the carbon material on the surface. The airflow crushing frequency is 23 Hz and the crushing air pressure is 0.55 MPa. Based on the total mass of the active cathode material, the titanium content is 1050 ppm and the volatile content is 950 ppm. (2) Production of the cathode foil:

[0299] The above active cathode material, the conductive agent, and the binder polyvinylidene fluoride are mixed in the solvent N-methylpyrrolidone in a mass ratio of 95:2:3 and then sufficiently mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. After completion of the stirring process, the cathode slurry is transferred to a coating process. The mixing process comprises premixing and main mixing, the mixing speed of the premixing being lower than that of the main mixing. The premixing has a rotational speed of 25 rpm and a self-rotation speed of 500 rpm, and the premixing has a mixing duration of 15 minutes. The conductive agent comprises conductive carbon black and multi-walled carbon nanotubes in a mass fraction of 1:1, the conductive carbon black having a specific surface area of ​​80 m². 2 / g and has an oil absorption value of 180 ml / 100 g and the carbon nanotubes have an average length of 20 µm, a specific surface area of ​​280 m² 2 exhibit / g.

[0300] The cathode slurry is coated onto an aluminum foil for drying, and after hot pressing, a cathode foil is produced with a one-sided thickness of the cathode film layer of 106.66 µm and a pressing density of 2.36 g / cm³. 3 obtained. The compression density here refers to the compression density when the battery cell is completely discharged. The drying temperature is 95°C and the drying rate is 2.0 m / min.

[0301] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 35 tonnes, 55 tonnes and 75 tonnes; and wherein the hot rolling temperature is 65°C, and wherein the electrode foil is heated before the first entry into the hot rolling press, and wherein the temperature of the heating is 50°C.

[0302] The cathode foil is cut into strips and punched into a predetermined shape, and the punched cathode foil is sorted by weight in a weighing and sorting machine and stacked in a stacking machine. Example 10

[0303] The manufacturing process of embodiment 10 is essentially the same as that of embodiment 1, with the difference that the manufacturing process of the active cathode material and the hot pressing process of the cathode foil are slightly different, and the differences are as follows: (1) The carbon source in the mixed raw material is sucrose and glucose, the mass of sucrose being 2 wt% compared to the mass of iron phosphate, and the mass of glucose being 5.7 wt% compared to the mass of iron phosphate; (2) The heating and sintering process differed. The precursor powder was sintered at least twice in a nitrogen atmosphere, with the first sintering temperature being 750°C and the holding time being 8 hours to obtain a first sintered product.

[0304] To the first sintered product, 1.5 wt% (based on the mass of the first sintered product) of glucose, 3.0 wt% (based on the mass of the first sintered product) of polyethylene glycol, titanium dioxide, and vanadium pentoxide are added. The mixture is ground uniformly and then divided into two groups for the second grinding. The two groups had different grinding parameters and were ground to a D v50 of 2.0 µm for the particles of the first grinding group and a D v50 The particle size of the second milling group was set to 0.35 µm. The milled particles from the first and second groups were mixed in a mass ratio of 30:70 and spray-dried for the second sintering. The temperature for the second sintering is 800°C and the holding time is 10 hours.

[0305] Based on the total mass of the active cathode material, the mass fraction of the Ti element is 1050 ppm and the mass fraction of the V element is 950 ppm.

[0306] (3) The cathode slurry is coated onto an aluminium foil for drying, and after hot pressing a cathode foil is produced with a one-sided thickness of the cathode film layer of 106.79 µm and a pressing density of 2.36 g / cm³. 3 obtained. The compression density here refers to the compression density when the battery cell is completely discharged. The drying temperature is 95°C and the drying rate is 2.0 m / min.

[0307] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 35 tonnes, 55 tonnes and 70 tonnes; and wherein the hot rolling temperature is 65°C, and wherein the electrode foil is heated before the first entry into the hot rolling press, and wherein the temperature of the heating is 50°C. Example 11

[0308] The manufacturing process of embodiment 11 is essentially the same as that of embodiment 1, with the difference that the sintering process of the active cathode material and the hot pressing process of the cathode foil are particularly different as follows:

[0309] (1) The precursor powder was sintered in two stages at elevated temperature in a nitrogen atmosphere to obtain the active cathode material: The temperature was increased from 25°C to 440°C at a heating rate of 2°C / min (first heating stage) and held for 2.5 hours. The temperature was then increased from 440°C to 760°C at a heating rate of 5°C / min (second heating stage) and held for 11 hours, producing the active cathode material consisting of lithium iron phosphate with the carbon material on the surface having a particle size Dv. 50A particle size of 1.6 µm is obtained through airflow comminution. The classification frequency of the airflow comminution is 25 Hz and the comminution air pressure is 0.55 MPa.

[0310] (2) The cathode slurry is coated onto an aluminium foil for drying, and after hot pressing a cathode foil is produced with a one-sided thickness of the cathode film layer of 106.10 µm and a pressing density of 2.35 g / cm³. 3 The density obtained refers to the density when the battery cell is completely discharged. The coating application rate is 20 m / min.

[0311] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 45 tonnes, 60 tonnes and 80 tonnes; and wherein the hot rolling temperature is 60°C, and wherein the electrode foil is heated before the first entry into the hot rolling press, and wherein the temperature of the heating is 40°C. Example 11

[0312] The manufacturing process of embodiment 11 is similar to the manufacturing process of embodiment 8, with the difference that in the production of the cathode foil, after the conductive agent and the binder polyvinylidene fluoride have been uniformly mixed in the solvent N-methylpyrrolidone in a mass ratio of 94.52:1.99:2.99, based on the total mass of the active cathode material, the conductive agent, the binder polyvinylidene fluoride and the dispersing agent, a dispersing agent HNBR is added at a mass ratio of 0.5% and then completely mixed, stirred and dispersed in a mixing vessel to produce a cathode slurry. Example 12

[0313] The manufacturing process of embodiment 12 is similar to the manufacturing process of embodiment 11, with the difference that in the production of the cathode foil, after the conductive agent and the binder polyvinylidene fluoride have been uniformly mixed in the solvent N-methylpyrrolidone in a mass ratio of 93.57:1.97:2.96, based on the total mass of the active cathode material, the conductive agent, the binder polyvinylidene fluoride and the dispersing agent, a dispersing agent HNBR is added at a mass ratio of 1.5%.

[0314] The manufacturing process of embodiment 13 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the cathode foil is adapted as follows: Example 13

[0315] The conductive medium used in embodiment 12 consists of conductive carbon black with a mass fraction of 2%, excluding carbon nanotubes, and the conductive carbon black has a specific surface area of ​​85 m². 2 / g and an oil absorption value of 200 ml / 100 g.

[0316] The manufacturing process of Comparative Example 1 is essentially the same as that of Exemplary Example 1, with the difference that the manufacturing process of the battery differs in particular as follows:

[0317] In comparative example 1, the folding process is a single fold.

[0318] The manufacturing process of comparative examples 2 and 3 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the cathode foil is adapted as follows: Comparative example 2

[0319] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot-pressing process, the cathode foil is produced with a one-sided cathode film thickness of 65.08 µm and a pressing density of 2.35 g / cm³. 3 The compression density refers here to the compression density when the battery cell is completely discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness adjustment of the cathode film layer. Comparative example 3

[0320] In embodiment 1, the cathode slurry was coated onto an aluminum foil for drying. By adjusting the pressure, calendering speed, roller gap, pressure holding time, number of calendering cycles, and controlling the surface density of the coating in the hot pressing process, the cathode foil is produced by hot pressing with a one-sided thickness of the cathode film layer of 125.64 µm and with a pressing density of 2.52 g / cm³ 3 The compression density refers here to the compression density when the battery cell is completely discharged, and the test procedure is described below. With the number of stacked film layers remaining unchanged, the thickness of the battery cell was adjusted according to the thickness adjustment of the cathode film layer.

[0321] The manufacturing process of comparative example 4 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the electrolyte is adapted as follows: Comparative example 4

[0322] The proportion of each solvent in the electrolyte is adjusted so that, based on the total mass of the electrolyte, the mass fraction of dimethyl carbonate is 36%, the mass fraction of methyl ethyl carbonate is 38.3%, the mass fraction of vinyl carbonate is 12.3% and the mass fraction of vinylidene carbonate is 0.9%.

[0323] The manufacturing process of comparative example 5 is essentially the same as that of embodiment 1, with the difference that the manufacturing process for the active cathode material is adapted as follows: Comparative example 5

[0324] The precursor powder was sintered in two stages at elevated temperature in a nitrogen atmosphere to obtain the active cathode material: The temperature was increased from 25°C to 500°C at a heating rate of 2°C / min (first heating stage) and held for 3.5 hours. The temperature was then increased from 550°C to 800°C at a heating rate of 5°C / min (second heating stage) and held for 13 hours. The active cathode material, consisting of lithium iron phosphate with carbon material on the surface and a particle size Dv50 of 1.6 µm, was obtained by airflow comminution. The airflow comminution frequency was 25 Hz and the comminution air pressure was 0.55 MPa. Test procedure: 1. Test of the electrode foil's compression density (fully discharged state)

[0325] The battery cell is placed in an oven environment at 25°C and stored for 2 hours. While maintaining the battery temperature at 25°C, the battery is discharged to 2.0 V at a constant current of 1 / 3 C. The battery is then disassembled to obtain a cathode foil. The remaining electrolyte solution is treated using the solvent dimethyl carbonate. The electrode foil is dried and cut into a small round disc with area S to obtain mass W1. Using a micrometer, the thickness T1 of the cathode foil is measured. The cathode film layer is then wiped from the weighed electrode foil. The mass of the collector is weighed and recorded as W2. The thickness T2 of the collector is measured using a micrometer. The density PD of the cathode film layer is then = (W1-W2) / [(T1-T2)×S]. 2. Rebound rate test

[0326] The cathode foil obtained by pressing was measured with a laser thickness gauge to determine the thickness of the initial cathode film layer on one side, recorded as T0, in µm. It was then combined with other components and processed to form a battery cell. The battery was charged at 25°C at a rate of 0.5C to 3.65V of the cell's nominal capacity, then charged at a constant voltage of 3.65V to 0.05C and left to stand for 10 minutes. It was then discharged at a rate of 1C to 2.5V and left to stand for 10 minutes. This single charge / discharge cycle constitutes one cycle. After repeating this cycle 100 times, the battery cell was disassembled, the cathode foil was collected and left to stand for 1 hour, and the thickness of the cathode film layer on one side after the cycle was measured with the laser thickness gauge and recorded as T1 in µm.The rebound rate of the battery cell is calculated as follows: Rebound rate = (T1-T0) / T0× 100%. 3. Gas production test

[0327] The battery is charged at 25°C at a rate of 0.5C to 3.65V of the nominal capacity of the battery cell, then charged at a constant voltage of 3.65V to 0.05C and left to stand for 10 minutes. It is then discharged at a rate of 1C to 2.5V and left to stand for another 10 minutes. The initial thickness (T2) of the battery cell is measured at 25°C in micrometers using a laser thickness gauge. This single charge / discharge cycle is one cycle. After repeating the cycle 100 times, the battery is left to stand for 1 hour, and the thickness of the battery cell after the cycle (T3) is measured in micrometers using a laser thickness gauge. The gas generation of the battery cell is calculated as follows: Gas generation = (T3 - T2) / T2 × 100%.

[0328] The battery cells of each embodiment and comparative example are manufactured separately according to the above method; the specific parameters and performance parameters are shown in the following tables. Table 1 Folding edges electrolyte cathode foil Rebound rate ① Gas production quantity ② DMC salary t / % EMC content t / % EC content t / % One-sided thickness of the cathode film layer µm Area fraction of particles with a particle size R1≥1000nm / % Pressure density of the cathode foil in a fully discharged state / cm³ 3 Implementation example 1 Double-folded edges 26 43,3 17,3 106,09 36,83 2,35 small small Implementation example 2 Double-folded edges 26 43,3 17,3 70,45 36,75 2,35 small small Implementation example 3 Double-folded edges 26 43,3 17,3 91,88 38,09 2,36 small small Implementation example 4 Double-folded edges 26 43,3 17,3 119,49 36,92 2,35 medium small Implementation example 5 Double-folded edges 26 43,3 17,3 96,75 36,95 2,55 medium small Implementation example 6 Double-folded edges 18 47,3 21,3 106,10 36,89 2,35 small small Implementation example 7 Double-folded edges 32 40,3 14,3 106,02 36,71 2,35 small medium Implementation example 8 Double-folded edges 26 43,3 17,3 106,34 34,89 2,35 small small Implementation example 9 Double-folded edges 26 43,3 17,3 106,66 34,97 2,36 small small Implementation example 10 Double-folded edges 26 43,3 17,3 106,79 49,99 2,36 medium small Implementation example 11 Double-folded edges 26 43,3 17,3 106,10 12,11 2,35 small small Comparative example 1 Single fold edges 26 43,3 17,3 105,64 36,64 2,35 / / Comparative example 2 Double-folded edges 26 43,3 17,3 65,08 36,70 2,35 small small Comparative example 3 Double-folded edges 26 43,3 17,3 125,64 36,90 2,52 large small Comparative example 4 Double-folded edges 36 38,3 12,3 105,64 36,64 2,35 small large Comparative example 5 Double-folded edges 26-sided 43,3 17,3 106,79 56,75% 2,36 large small ① Small: rebound rate below 2%; medium: rebound rate 2-5% (except 2%); large: rebound rate above 5% (except 5%) 2 Small: Gas production below 1.5%; medium: Gas production 1.5%-2% (except 1.5%); large: Gas production above 2% (except 2%)

[0329] In comparative example 1, only the first sealing zone is arranged with a single folded edge, resulting in encapsulation failure during long-term cycles with low reliability. In comparative example 2, the cathode film layer thickness is small, the space occupied by the active cathode material is small, and the battery cell capacity is low. In comparative example 3, the cathode film layer thickness is too large, the rebound phenomenon is severe, and the pressure in the sealing zone increases, impairing the long-term reliability of the battery cell. In comparative example 4, the DMC content in the electrolyte is too high, easily leading to gas generation and an increase in the internal pressure of the battery cell, resulting in encapsulation failure and reduced battery cell reliability.In comparative example 5, the area fraction of particles with a particle size R1 of R1 ≥ 1000 nm is too large, the cathode film layer recedes sharply, and the sealing zone of the battery cell is extremely prone to failure.

[0330] With reference to Fig. 1 In the embodiments of the present application, the battery cell is described in particular as follows:

[0331] A battery cell comprising a stacked electrical core and a housing, wherein the stacked electrical core is contained in the housing, the housing being a soft packing material; wherein the housing comprises a first sealing zone, the first sealing zone being arranged at at least one end of the stacked electrical core extending in a width direction; wherein the first sealing zone comprises a double-folded edge structure extending along a length direction, the double-folded edge structure being provided with an encapsulation adhesive, the encapsulation adhesive being arranged continuously along the length direction and securing the double-folded edge structure;wherein the stacked electrical core comprises a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer provided on at least one side of the cathode collector, wherein the cathode film layer comprises lithium-containing transition metal phosphate particles, wherein at least a portion of the surface of the lithium-containing transition metal phosphate particles is provided with a carbon material; wherein, based on a total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-50%; wherein a one-sided thickness of the cathode film layer is designated as H and H is 70 µm-120 µm; wherein the density of the cathode foil when the battery cell is in a fully discharged state is 2.3 g / cm³; 3 -2.6 g / cm² 3is; wherein the electrolyte comprises a solvent, wherein the solvent comprises dimethyl carbonate (DMC); wherein, based on the total mass of the electrolyte, the percentage by mass of dimethyl carbonate is 18%-32%.

[0332] In this way, the capacity and energy density of the battery cell are increased by a stacked electrical core structure, a greater thickness of the cathode film layer, a high pressing density and a larger area fraction of particles with a particle size R1, and the double-folded edge structure of the first sealing zone and the interaction of the encapsulation adhesive can significantly improve the mechanical strength of the sealing zone and reduce the possibility of the battery cell failing due to internal pressure during a long cycle process.

[0333] As can be seen from embodiments 1, 8, 9, 11 and embodiment 10, based on the total area of ​​the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, if the area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-40%, the rebound rate is further reduced, which contributes to improving the long-term reliability of the battery cell. Table 2 L R1 A50 Uniformity of particle distribution with a particle size R1 ≥ 1000 nm / % Graphitization degree dC50 Coating value B50 One-sided thickness of the cathode film layer µm Pressure density of the cathode foil in a fully discharged state / cm³ 3 Rebound rate ① Gas production s-quantity② Implementation example 1 0,687 1,90 1,00 0,369 105,64 2,36 small small Implementation example 8 0,673 0,99 1,02 0,446 105,89 2,36 small small Implementation example 9 0,745 1,47 1,04 0,368 106,21 2,37 small small Example 10 0,72 4,91 1,02 0,456 106,34 2,37 medium small Example of implementation 11 0,75 1,82 0,98 0,355 105,65 2,36 small small ① Small: rebound rate below 2%; medium: rebound rate 2-5% (except 2%); large: rebound rate above 5% (except 5%) 2 Small: Gas production below 1.5%; medium: Gas production 1.5%-2% (except 1.5%); large: Gas production above 2% (except 2%)

[0334] As can be seen from examples 1, 8-11, the median L is R1A50The sphericity in the cumulative distribution curve of the sphericity area of ​​particles with a particle size R1 of R1 ≥ 1000 nm, based on the total area of ​​the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, 0.6–0.8; If the distribution uniformity of particles with a particle size R1 of R1 ≥ 1000 nm is less than or equal to 5%, the battery cell has a lower rebound rate and gas generation rate. The median L R1A50 The sphericity is 0.67-0.75 in the cumulative distribution curve of the sphericity area of ​​particles with a particle size R1 of R1≥1000nm; The distribution uniformity of particles with a particle size R1 of R1 ≥ 1000 is in the range of 0.2%-2%, which contributes to a further improvement in the stability of the battery during long cycles. Table 3 Type of dispersant Content of the dispersing agent Uniformity of particle distribution with a particle size R1≥1000nm / % Rebound rate ① Example 8 / / 0,99 small Example 11 HNBR 0,5% 0,45 small Example 12 HNBR 1,5% 0,24 small ① Small: rebound rate below 2%; medium: rebound rate 2-5% (except 2%); large: rebound rate above 5% (except 5%)

[0335] As can be seen from embodiments 8, 11 and 12, the distribution uniformity of the particles with a particle size R1 of R1 ≥1000 nm is in the range of 0.2% to 0.9%, which helps to further reduce the voltage concentration and reduce the rebound of the cathode film layer, thereby improving the reliability of the battery during long cycles. Table 4 CNT content Rebound rate ① Implementation example 1 0,67% small Implementation example 13 0% medium ① Small: rebound rate below 2%; medium: rebound rate 2-5% (except 2%); large: rebound rate above 5% (except 5%)

[0336] As can be seen from the comparison between embodiment 1 and embodiment 13, the conductive medium comprises carbon nanotubes, and the mass fraction C1 of the carbon nanotubes satisfies: 0 <C1≤2,5%, was dazu beiträgt, den Rückprall der Kathodenfilmschicht während des Zyklus zu verringern, wodurch die langfristige Zuverlässigkeit der Batterie verbessert wird.

[0337] It should be noted that the present application is not limited to the embodiments mentioned above. The embodiments mentioned above are only examples, and embodiments within the scope of the technical solution of the present application that have essentially the same composition as the technical idea and have the same effect are included in the technical scope of the present application. Furthermore, within the scope of the present application, other possibilities for constructing the embodiments by combining some of the constituent elements of the embodiments and applying various deformations to the embodiments that a person skilled in the art can imagine without departing from the subject matter of the present application are also included.

Claims

Battery cell, characterized in that it comprises a stacked electrical core and a housing, wherein the stacked electrical core is received in the housing, the housing being a soft packing material; wherein the housing comprises a first sealing zone, the first sealing zone being arranged at at least one end of the stacked electrical core extending in a width direction; wherein the first sealing zone comprises a double-folded edge structure extending along a length direction, the double-folded edge structure being provided with an encapsulation adhesive, the encapsulation adhesive being arranged continuously along the length direction and securing the double-folded edge structure;wherein the stacked electrical core comprises a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer provided on at least one side of the cathode collector, wherein the cathode film layer comprises lithium-containing transition metal phosphate particles, wherein at least a portion of the surface of the lithium-containing transition metal phosphate particles is provided with a carbon material; wherein, based on a total area of ​​the particles in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-50%; wherein a one-sided thickness of the cathode film layer is designated as H and H is 70 µm-120 µm; wherein the density of the cathode foil when the battery cell is in a fully discharged state is 2.3 g / cm3-2.6 g / cm3;wherein the electrolyte comprises a solvent, wherein the solvent comprises dimethyl carbonate (DMC); wherein, based on the total mass of the electrolyte, the percentage by mass of dimethyl carbonate is 18%-32%. Battery cell according to claim 1, characterized in that the one-sided thickness of the cathode film layer is designated as H and H is 90 µm-120 µm, optionally 100 µm-120 µm. Battery cell according to claim 1 or 2, characterized in that the housing comprises at least one second sealing zone, wherein the second sealing zone is arranged at at least one end of the stacked electrical core along the longitudinal direction of the housing, wherein the second sealing zone is arranged on one side of the electrode tab of the stacked electrical core. Battery cell according to one of claims 1 to 3, characterized in that a plurality of adhesive rings circumferentially in the width direction are arranged around an outer circumference of the stacked electrical core, wherein the adhesive rings circumferentially in the width direction are arranged at intervals along the length direction. Battery cell according to one of claims 1 to 4, characterized in that, with reference to the total area of ​​the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the percentage area fraction of the particles with a particle size R1 of R1≥1000 nm is 12%-37%. Battery cell according to one of claims 1 to 5, characterized in that in a cumulative distribution curve of the sphericity area of ​​the particles with a particle size R1 of R1≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil the median LR1A50 of the sphericity is 0.6-0.8, optionally 0.65-0.75, further optionally 0.67-0.

75. Battery cell according to one of claims 1 to 6, characterized in that the distribution uniformity of the particles with a particle size R1 of R1≥1000 nm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is less than or equal to 5%, optionally 0.2%-2%, further optionally 0.2%-0.9%. A battery cell according to any one of claims 1 to 7, characterized in that the electrolyte meets at least one of the following conditions: (1) the solvent in the electrolyte further comprises one or both of ethyl methyl carbonate (EMC) and ethylene carbonate (EC); (2) based on the total mass of the electrolyte, the percentage by mass of ethyl methyl carbonate (EMC) is 39%–49%; (3) based on the total mass of the electrolyte, the percentage by mass of ethylene carbonate (EC) is 13%–22%; (4) based on the total mass of the electrolyte, the total percentage by mass of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) is 52%–71%; (5) the electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6) and the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / L–1.2 mol / L (6) the percentage by mass of dimethyl carbonate is 18%-26%, based on the total mass of the electrolyte. Battery cell according to one of claims 1 to 8, characterized in that the median C50 of the graphitization degree in the cumulative distribution curve for the graphitization C value of the cathode film layer obtained in the area scanning mode of the laser microconfocal Raman spectrometer is 0.95-1.20; wherein the graphitization C value is IG / ID, where IG represents the intensity of the G-peak of the Raman spectrum at 1580±100cm-1 and ID represents the intensity of the D-peak of the Raman spectrum at 1350±100cm-1. Battery cell according to one of claims 1 to 9, characterized in that the median B50 of the coating value in the cumulative distribution curve for the coating value-B of the cathode film layer, which is obtained in the area scanning mode of the laser microconfocal Raman spectrometer, is 0.30-0.60; wherein the coating value-B is IP / ID, where IP represents the intensity of the P-peak of the Raman spectrum at 948±100cm-1 and ID represents the intensity of the D-peak of the Raman spectrum at 1350±100cm-1. Battery cell according to one of claims 1 to 10, characterized in that the lithium-containing transition metal phosphate particles comprise iron, wherein the cathode film layer has an iron dissolution rate of 658 ppm-1921 ppm, optionally 658 ppm-1485 ppm. Battery cell according to one of claims 1 to 11, characterized in that the cathode film layer further comprises a conductive means, wherein, with respect to the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the proportion of the total area of ​​an agglomeration region of the conductive means is 0.5%-2.5%, optionally 0.5%-1.7%. Battery cell according to claim 12, characterized in that the conductive means comprises carbon nanotubes, wherein the carbon nanotubes comprise one or more of cin-walled carbon nanotubes, thin-walled carbon nanotubes, multi-walled carbon nanotubes, wherein the conductive means further optionally comprises conductive carbon black. Battery cell according to claim 12 or 13, characterized in that the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black. Battery cell according to claim 14, characterized in that, with respect to the mass of the cathode film layer, the mass content C1 of the carbon nanotubes is 0 <C1≤2,5% und der Massengehalt C2 des leitfähigen Rußes 0<C1≤2,5% erfüllt. Battery cell according to one of claims 1 to 15, characterized in that the cathode film layer further comprises a dispersing agent, wherein the dispersing agent comprises hydrogenated nitrile butadiene rubber HNBR. Battery cell according to claim 16, characterized in that the mass content of the dispersing agent is 0.5%-2%, based on the mass of the cathode film layer. Battery cell according to one of claims 1 to 17, characterized in that the porosity of the cathode film layer is 14%-28%. Battery cell according to one of claims 1 to 18, characterized in that the battery cell further comprises a separator arranged between the cathode foil and the anode foil, wherein the separator comprises a base film and a ceramic layer arranged on both sides of the base film, and a bonding layer arranged on at least one of the sides of the ceramic layer facing away from the base film, wherein the bonding layer is a continuous layer with a porous structure, and wherein the bonding layer comprises a vinylidene fluoride polymer. Battery cell according to one of claims 1 to 19, characterized in that the cathode film layer is provided with a lower coating layer in a lower region facing the cathode collector, wherein the lower coating layer fulfills at least one of the following conditions: (1) the lower coating layer comprises a conductive agent and a binder, wherein the conductive agent comprises carbon nanotubes and conductive carbon black, and wherein the binder comprises a vinylidene fluoride polymer; (2) the thickness of the lower coating layer is 0.5 µm-5 µm. Battery cell according to one of claims 1 to 20, characterized in that the lithium-containing transition metal phosphate particles in the cathode film layer comprise a component with a general formula as follows: LimFexPyOjQqFormula I: wherein Q comprises one or more of Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, Cl, Br, and wherein 0.8≤m≤1.15, 0.9≤x≤1, 0.95≤y≤1, 3.5≤j≤4, 0≤q≤0.

1. Battery cell according to one of claims 1 to 21, characterized in that the lithium-containing transition metal phosphate particles comprise titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of titanium is 500 ppm-8000 ppm, optionally 1000 ppm-3000 ppm. Battery cell according to one of claims 1 to 22, characterized in that the lithium-containing transition metal phosphate particles comprise vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer, the mass content of vanadium is 500 ppm-5000 ppm, optionally 500 ppm-3000 ppm. Battery cell according to one of claims 1 to 23, characterized in that the soft packaging material comprises an aluminum-plastic composite film, optionally a composite film formed from one or more of aluminum, polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE) with aluminum; Battery cell according to one of claims 1 to 24, characterized in that at least one stacked electrical core is received in the housing, wherein the housing has a dimension of L0 in the longitudinal direction, wherein the housing has a dimension of W0 in the width direction, wherein the housing has a dimension of H0 in the thickness direction, wherein 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm, and 14 mm ≤ H0 ≤ 22 mm. Battery cell according to claim 25, characterized in that the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 450 mm ≤ L0 ≤ 650 mm. Battery cell according to claim 25, characterized in that the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 900 mm ≤ L0 ≤ 1300 mm. Battery cell according to one of claims 1 to 27, characterized in that the capacity of the battery cell at 25°C is 105 Ah-300 Ah, optionally 150 Ah-190 Ah. Battery device, characterized in that it comprises a battery cell according to any one of claims 1 to 28. Power-consuming device, characterized in that the power-consuming device comprises a battery device according to claim 29, wherein the battery device is used to provide electrical energy. Energy storage device characterized in that the energy storage device comprises a battery device according to claim 29, wherein the battery device is used for storing electrical energy.

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