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

Abstract

Battery cell characterized in that it comprises a stacked electrical core, wherein the stacked electrical core comprises a cathode foil, an anode foil and a separator provided between the cathode foil and the anode foil; 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; wherein a percentage area fraction of the particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%; 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 side of the ceramic layer facing the cathode foil and the side 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.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of battery cells, 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 market's demand for range and lifespan of power-consuming devices doubling, the requirements for battery cell capacity and cycle life have also increased. However, achieving simultaneous improvements in these performance areas with current technology is difficult, making it a technical problem that urgently needs to be addressed in this field. DISCLOSURE OF REGISTRATION

[0004] The present application is made in view of the aforementioned subject matter with the purpose of providing a battery cell with high capacity and good cycle performance.

[0005] A first aspect of the present application provides a battery cell comprising a stacked electrical core, wherein the stacked electrical core comprises a cathode foil, an anode foil and a separator provided between the cathode foil and the anode foil, 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; wherein a percentage area fraction of the particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%;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 side of the ceramic layer facing the cathode foil and the side 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.

[0006] The applicant found that if the percentage area fraction of particles with a particle size of 1 µm or greater in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is less than 12%, insufficient particle gradation significantly limits the scope for improvement in packing density and makes it difficult to effectively improve battery capacity. Furthermore, if the area fraction of particles with a particle size of 1 µm or greater in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil exceeds 50%, too many large particles can cause a serious rebound phenomenon in the cathode film layer, leading to SEI film breakage and cracking, thereby increasing the risk of short circuits and impairing battery cycle performance.

[0007] The embodiments of the present application improve battery capacity by combining a stacked electrical core with a cathode film layer of lithium-containing transition metal phosphate with a specific large particle content, and furthermore by using a separator with a ceramic layer on both sides to increase the separator's stiffness. Simultaneously, the separator is used with a continuous layer having a porous structure, which has a larger bonding area and stronger bonding force, to increase the bonding effect between the separator and the cathode film, improve the density and stiffness of the internal formation of the stacked electrical core, and compensate for the lack of low external bonding force of the stacked electrical core.This reduces the risk of horizontal displacement due to the mutual extrusion of the cathode foil and the anode foil in the thickness direction during the rebound process of the electrical core, and reduces the risk of overlapping of the cathode foil and the anode foil, which in turn triggers a short circuit, in order to further improve the cycle performance of the battery based on good battery capacity.

[0008] In each embodiment, the percentage area fraction of particles with a particle size of 1 µm-5 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%.

[0009] The area fraction of particles with a particle size of 1 µm-5 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which contributes to improving the rebound phenomenon of large particles in the electrode foil in the battery's cycling process and to improving the battery's cycle performance based on maintaining the battery's high capacity.

[0010] In each embodiment, the percentage area fraction of particles with a particle size of 1 µm-5 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-40%.

[0011] The area fraction of particles with a particle size of 1 µm-5 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which contributes to a further improvement of the rebound phenomenon in the electrode foil, which is caused by large particles in the electrode foil that tend to concentrate the voltage, and to a reduction in the probability that the anode film layer of the electrode foil comes into contact with the cathode film layer and causes short circuits, based on the maintenance of the high capacity of the battery.

[0012] In each embodiment, the vinylidene fluoride polymer comprises one or more of the following materials: polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).

[0013] In every embodiment, the one-sided thickness of the cathode film layer is 70 µm-120 µm.

[0014] The gram capacity of lithium-containing transition metal phosphate particles is relatively low, and research has shown that it is difficult to meet market demand when the one-sided thickness of the cathode film layer is less than 70 µm. The one-sided thickness of the cathode film layer is within the range mentioned above, which contributes to improving the battery cell's capacity.

[0015] In each embodiment, the one-sided thickness of the cathode film layer is 90 µm-120 µm.

[0016] The thickness of the cathode film layer on one side is within the range above, which contributes to a further improvement in the battery's capacity.

[0017] In each embodiment, the one-sided thickness of the cathode film layer is 100 µm-120 µm.

[0018] Increasing the thickness of the cathode film layer on one side contributes to improving the battery's capacity, and the applicant found that the phenomenon of particle rebound in the cathode film layer is more severe when the thickness of the cathode film layer on one side is greater than or equal to 100 µm. The embodiments of the present application effectively reduce the severe rebound of the thickly coated film layer in the stacked electrical core, and the battery exhibits improved cycle performance while maintaining a high capacity.

[0019] In each embodiment, the cathode film layer comprises a first region, wherein the first region is located on a top side of the cathode film layer facing away from the cathode collector, wherein the distribution uniformity of particles with a particle size of more than or equal to 1 µm in the first region is 0.2%-5%.

[0020] In each embodiment, the cathode film layer comprises a first region, wherein the first region is located on a top side of the cathode film layer facing away from the cathode collector, wherein the distribution uniformity of particles with a particle size of more than or equal to 1 µm in the first region is 0.2%-3.5%.

[0021] The degree of voltage concentration on the large particles and on the small particles in the cathode film layer differs, which is associated with the gradual release of voltage during the cycle process, leading to different degrees of rebound in the electrode.The embodiments of the present application have a certain content of large particles, and at the same time the large particles are uniformly distributed in the electrode foil, so that the extrusion pressure of the cathode film layer on the separator has a uniform distribution, thereby reducing the risk of local excessive extrusion and local blockage of the lithium ion transfer path caused by a non-uniform distribution of the large particles, which triggers an increase in peripheral current density and facilitates the precipitation of lithium, so that the battery has a good capacity based on a further improvement in the cycle performance of the battery.

[0022] In each embodiment, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L is A50 sphericity 0.6-0.8.

[0023] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, and the larger particles have a better sphericity, which reduces particle bridging due to the irregular shape of the large particles, reduces the void content in the electrode foil and simultaneously reduces the voltage concentration, which is exacerbated by the irregularity of the large particles, thus reducing the rebound of the electrode foil due to voltage release during the cycle, so that the battery cell has a high capacity and its cycle performance is further improved.

[0024] In each embodiment, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L is A50 sphericity 0.65-0.75.

[0025] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, which contributes to reducing the voltage concentration of the large particles, which is exacerbated by the irregularity of the large particles, thus reducing the rebound of the electrode foil due to the voltage release during the cycle, thereby improving the cycle performance of the battery.

[0026] In each embodiment, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L is A50 sphericity 0.67-0.75.

[0027] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, which contributes to a further improvement in the voltage concentration of the large particles, reducing the rebound of the electrode foil due to voltage release during the cycle, thus further improving the cycle life of the battery cell.

[0028] In each embodiment, the median is C 50of the degree of graphitization in the cumulative distribution curve for a graphitization C value of the cathode film layer obtained in an area scanning mode of the laser microconfocal Raman spectrometer, is greater than 0.95 and less than or equal to 1.20; where the graphitization C value I G / I D is, 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.

[0029] In the cumulative distribution curve of the graphitization C value of the cathode film layer, obtained in an area scanning mode of the laser microconfocal Raman spectrometer, the median C lies 50of the graphitization degree within the above range, so that the pressing density of the electrode foil can be further improved, thereby reducing the proportion of large particles in the cathode film layer, which helps to reduce the rebound phenomenon of the film layer due to too many large particles, and further improves the cycle performance of the battery, based on maintaining the battery's capacity.

[0030] In each embodiment, the median B is 50 of 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 is IP / ID, where IP is the intensity of the P-peak of the Raman spectrum at 948±100cm -1 and ID for the intensity of the D-peak of the Raman spectrum at 1350±100cm -1 stands.

[0031] The median B50 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. This improves the uniformity of the cathode film layer's sliding during roller pressing and reduces the phenomenon of stress concentration within the cathode film layer. Furthermore, the dense and uniform carbon material layer facilitates the sliding of large particles within the cathode film layer during the pressing process. This reduces stress concentration on these large particles, decreases rebound due to stress release during the cycle, and ultimately improves the battery's cycle life.

[0032] In each embodiment, the iron dissolution rate of the cathode material is 658 ppm-1921 ppm, optionally 658 ppm-1485 ppm.

[0033] The iron dissolved in the cathode material originates primarily from the lithium-containing transition metal phosphate particles of the active cathode material. The iron dissolution rate depends on the number of lattice defects in the lithium-containing transition metal phosphate particles and on the completeness and density of the carbon material layer 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 particles, which reduces lattice corrosion in the weakly acidic environment. Conversely, the more complete and dense the carbon material layer on the surface of the active cathode material, the more inhibits the dissolution of iron ions in the weakly acidic environment.The cathode material, with an iron dissolution rate within the above range, exhibits relatively few lattice defects and has a complete and dense carbon material layer. This is conducive to improving the compression resistance and the degree of 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. This improves the rebound phenomenon of large particles due to stress concentration, thus further improving the cycle performance of the battery, based on the battery's good capacity.

[0034] In each embodiment, the lithium-containing transition metal phosphate particles in the cathode film layer comprise a component with the following general formula: Li m Fe 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.

[0035] 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.

[0036] 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 particles 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 increases electrode rebound during cycling.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 titanium content 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, which reduces the stress concentration in the cathode film layer and improves the rebound phenomenon of the large particles due to the stress concentration, thus further improving the cycle performance of the battery, based on the fact that the battery has a good capacity.

[0037] Simultaneously, the doping of titanium 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 cathode 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 to enhance the battery's kinetics.

[0038] 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.

[0039] 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 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 further enhancing the kinetic and cycle performance of the battery cell.

[0040] The vanadium content in the above area contributes to improving the kinetic performance of the cathode foil and the kinetic performance of the 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 lithium-containing transition metal phosphate battery.

[0041] 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 0.2%-6%, optionally 1.5%-5%.

[0042] Based on the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the total area of ​​the agglomeration region of the conductive agent lies within the above range, indicating that the conductive agent is uniformly dispersed in the cathode film layer and that it is easy to form a homogeneous conductive network, which helps to reduce local polarization or even lithium precipitation of the battery during the cycling process.

[0043] 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 can inhibit the rebound of the lithium-containing transition metal phosphate particles 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 breakage of the SEI film and the film layer during the rebound process of the film layer and extend the life of the battery.

[0044] 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, multi-walled carbon nanotubes, wherein the conductive means further optionally comprises conductive carbon black.

[0045] Carbon nanotubes have a high length-to-diameter ratio, which facilitates thickness-directed overlap between a multitude of cathode particles and other particles, forming a long-distance conductive path and simultaneously improving the binding force between the particles, reducing local polarization and even lithium precipitation during the battery cycle, and improving battery life; furthermore, the binding effect reduces the rebound phenomenon of large particles in the cathode film layer, thereby improving the battery's cycle performance.

[0046] Conductive carbon black is small in size, adheres to the surface of the cathode particles, and fills the gaps between them, creating a dense, point-like conductive contact. The combination of carbon nanotubes and carbon black further enhances the conductive network within the cathode film layer, addressing both long-range and short-range conductivity. Simultaneously, the conductive material has a large specific surface area, which facilitates the absorption and retention of electrolyte solution. This reduces electrolyte extrusion, a phenomenon caused by the significant increase in electrode film expansion during extended cycles, and can thus improve battery lifespan.

[0047] In each embodiment, the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black.

[0048] 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. 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 nanotubes, and thus inhibits agglomeration, 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 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 cathode film delamination and further improving the kinetic performance and lifetime of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive medium also blocks 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.

[0049] 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%.

[0050] The mass content of carbon nanotubes and conductive carbon black within the above range can effectively reduce the agglomeration phenomenon of carbon nanotubes and form a good conductive network structure, thereby effectively reducing the voltage concentration of the cathode film layer and improving the retention rate of electrolyte solution of the cathode film layer during long cycles, thereby further reducing the risk of electrode foil film layer delamination and the degree of polarization, increasing the kinetic performance of the battery and improving the cycle life of the battery.

[0051] In each embodiment, the cathode film layer further comprises a dispersing agent, wherein the dispersing agent comprises hydrogenated nitrile butadiene rubber HNBR.

[0052] The polar groups (e.g., cyano group, -CN) in the HNBR hydrogenated nitrile butadiene rubber molecule 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., hydrogen bonding, dipole effect) to improve the compatibility of the particles with the solvent and to reduce the interfacial tension between the particles and the solvent, especially the interfacial tension of large particles. In this way, the particles can be dispersed more easily and uniformly in the film layer, thereby reducing aggregation due to hydrophobicity, improving the dispersion of large particles in the cathode film layer, and lowering the concentration of stresses generated during the stamping of the cathode film layer.

[0053] When the slurry is dried to form a film, the elastic network structure of HNBR can buffer the shrinkage stress generated by solvent evaporation, regroup the conductive agent in the process due to capillary action, and reduce the area fraction of the conductive agent agglomeration region, thereby improving the battery cycle life.

[0054] In each embodiment, the mass content of the conductive medium is 0.5%-2%, based on the mass of the cathode film layer.

[0055] 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 in the cathode film layer, and ensuring that the battery has good capacity and cycle performance.

[0056] In each embodiment, 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 3 .

[0057] In each embodiment, the porosity of the cathode film layer is 14%-28%.

[0058] The porosity of the cathode film layer lies within the above range; on the one hand, it is beneficial for improving the properties of the liquid retention of the electrolyte solution, the improvement of the ion diffusion capacity of the cathode film layer with a certain area fraction of large particles, and the improvement of the kinetic performance of the battery.

[0059] In each embodiment, the cathode film layer is provided with a lower coating layer at a lower area 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 the binder comprises a vinylidene fluoride polymer.

[0060] In each embodiment, 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.

[0061] 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 decreasing the probability of cathode film layer delamination and improving the cycle stability of the battery. 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.

[0062] In each embodiment, the thickness of the base film is 7 µm-9 µm.

[0063] In each embodiment, the thickness of the ceramic layer on one side is 2 µm-4 µm.

[0064] In each embodiment, the thickness of the bonding layer on one side is 1 µm-5 µm.

[0065] If the thickness of the bonding layer is too small, the space for buffer expansion in the separator is limited, and the bonding force between the separator and the electrode film is weak. On the one hand, this increases the probability of elevated voltage after film expansion and delamination, impacting the battery's lifetime; on the other hand, it increases the probability of a short circuit at the cathode and anode overlap, negatively affecting the battery's safety performance. Conversely, if the bonding layer thickness is too large and the battery's volumetric energy density is high, it negatively impacts the battery's volumetric energy density. In the embodiments of the present application, the bonding layer thickness is within the aforementioned range, thus balancing the battery's cycle life, safety performance, and volumetric energy density.

[0066] In each embodiment, the battery cell comprises a housing, wherein the stacked electrical core is contained 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.

[0067] The dimensions of the housing of the battery cell of the embodiments of the present application are within the above range, which contributes to achieving a better battery capacity.

[0068] In each embodiment, the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 450 mm ≤ L0 ≤ 650 mm.

[0069] 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 uniformity of the electrolyte solution, further promoting the uniformity of lithium ion disembedding during the cycling process, mitigating the phenomenon of voltage concentration, reducing the film layer rebound, and improving the cycle stability of the battery cell.

[0070] In each embodiment, the dimension L0 of the housing in the longitudinal direction satisfies the following condition: 900mm ≤ L0 ≤ 1300mm.

[0071] If the length dimension L1 of the casing meets the following condition: 900 mm ≤ L1 ≤ 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 volume energy density of the battery cell.

[0072] In each embodiment, the housing material is a soft packaging material, wherein the soft packaging material comprises an aluminum-plastic composite film, optionally comprising 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.

[0073] The soft packing material has high elasticity, allowing for a thinner and softer casing, which helps improve space utilization within the battery cell and thus increase its energy density. Furthermore, the high barrier properties of aluminum effectively reduce the penetration of water and oxygen into the battery's interior, thereby minimizing electrolyte degradation and electrode material oxidation, thus extending the battery's lifespan.

[0074] In each embodiment, the housing comprises a first sealing zone, wherein the first sealing zone is provided at at least one end extending in the width direction of the stacked electrical core; wherein the first sealing zone comprises a folded edge structure extending in the length direction, wherein the folded edge structure is provided with an encapsulating adhesive, wherein the encapsulating adhesive is provided successively along the length direction and secures the folded edge structure.

[0075] The embodiments of the present application further improve the sealing strength of the first sealing zone by incorporating a folded edge structure extending along the longitudinal direction within the first sealing zone. The encapsulation adhesive is continuously applied along the longitudinal direction and secures the folded edge structure, in contrast to discontinuous application of the encapsulation adhesive along the longitudinal direction. This further improves the encapsulation strength, achieves continuous reinforcement of the sealing zone in the longitudinal direction, and reduces the likelihood of the electrode foil popping out of the sealing zone of the packaging during the cycle rebound process.

[0076] 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 extending 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.

[0077] 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 directed pressure relief of the battery, reducing the effects of thermal runaway on the adjacent electrical core, and improving the overall lifespan of the battery.

[0078] 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.

[0079] The spaced arrangement of the adhesive rings in the longitudinal direction, which surround the electrical core along the lateral direction, is beneficial for fixing the position between the electrode foils in the electrical core and reducing the probability of displacement of the electrical core when the battery is shaken. This is particularly suitable for long batteries, which can effectively reduce displacement between the electrode foils in the longitudinal direction and lead to the phenomenon of lithium precipitation. It is also beneficial for keeping the internal spatial structure of the battery stable, so that it does not affect the normal operation of the battery.

[0080] In each embodiment, the battery cell capacity at 25°C is 100 Ah-300 Ah, optionally 110 Ah-190 Ah, and further optionally 125 Ah-180 Ah.

[0081] In the battery cell of the embodiments of the present application, a suitable housing dimension is set to accommodate the stacked electrical core, and an appropriate proportion of large particles in the film layer of the electrode foil in the stacked electrical core is controlled so that the battery cell has a high capacity.

[0082] A second aspect of the present application provides a battery device comprising a battery cell according to the first aspect of the present application.

[0083] A third aspect of the present provides a power-consuming device, wherein the power-consuming device comprises a battery device according to the second aspect, wherein the battery device is used to provide electrical energy.

[0084] A third aspect of the present provides an energy storage device, wherein the energy storage device comprises a battery device according to the second aspect, wherein the battery device is used to store electrical energy. PRESENTATION OF THE REGISTRATION Fig. Figure 1 is a schematic representation of a separator in an embodiment of the present application; Fig. Figure 2 shows a schematic representation of a separator in the prior art; Fig. Figure 3 is a schematic representation of a surface morphology of a bonding layer of the separator of an embodiment of the present application; Fig. Figure 4 is a schematic representation of a cathode foil in an embodiment of the present application; Fig. 5 is a front view of a battery cell in an embodiment of the present application; Fig.Figure 6 shows a schematic representation of a power-consuming device in an embodiment of the present application. Reference symbol list:

[0085] 10 Cathode foil; 101 Cathode collector; 102 Cathode film layer; 102a First surface; 102b Second surface; 1021 First area; 20 Separator; 201 Base film; 202 Ceramic layer; 203 Bonding layer; 5 Battery cell; 50 Housing; 51 First sealing zone; 52 Second sealing zone; 53 Leading element; X Longitudinal direction; Y Width direction; Z Thickness direction. SPECIFIC EXECUTION FORMS

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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).

[0091] In the present application, the terms "plural" and "multiple" refer to two or more.

[0092] Unless otherwise stated, the terms used in this application have the known meanings as generally understood by those skilled in the art.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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 cell or 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.

[0101] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, and the like.

[0102] 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.

[0103] The battery cell comprises an electrode component and an electrolyte.

[0104] 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.

[0105] Lithium-containing transition metal phosphate materials offer advantages over lithium-containing transition metal oxide materials, including high safety, long lifespan, low cost, and stable high-temperature performance. However, their low gram capacity hinders improvements in battery capacity. The applicant found that, compared to a wound electric core, a stacked electric core eliminates corner areas and offers higher internal volume utilization. Furthermore, the use of a stacked electric core contributes to a further improvement in the battery's volumetric energy density. Simultaneously, a certain proportion of large particles helps to increase the film layer gradation, improve the electrode foil's packing density, and further enhance the battery's volumetric energy density.The stacked electrical core, however, has a higher capacitance because it lacks corner areas like those found in a wound electrical core. Due to the lack of radial bonding force, the shear force at the interface between the cathode foil, the anode foil, and the separator is weak, and relative slippage can easily occur during long cycles or under mechanical stress, increasing the risk of a short circuit.Simultaneously, the large particles in the film layer can easily generate a stress concentration during the pressing of the electrode foil. The gradual release of stresses during the cycling process causes the film layer to rebound. In the absence of an external binding force from the stacked electrical core, this rebound of the film layer is more likely to lead to a displacement between the cathode foil, the anode foil, and the separator. This further increases the risk of a local short circuit in the battery and degrades its cycle performance. The engineering problem of how to design a battery that exhibits both good capacity and good cycle performance must be solved within the scope of this research.

[0106] A first aspect of the present application provides a battery cell comprising a stacked electrical core, wherein the stacked electrical core comprises a cathode foil, an anode foil, and a separator provided between the cathode foil and the anode foil, 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 a percentage area fraction of the particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%–50%; The structure of the separator is as shown in Fig.Figure 1, wherein the separator 20 comprises a base film 201, a ceramic layer 202 provided on both sides of the base film 201, and a binder layer 203 provided on at least one side of the ceramic layer 202 facing the cathode foil and the base film 201 away, wherein the binder layer 203 is a continuous layer with a porous structure, and wherein the binder layer 203 comprises a vinylidene fluoride polymer.

[0107] The applicant found that if the percentage area fraction of particles with a particle size of 1 µm or greater in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is less than 12%, insufficient particle gradation significantly limits the scope for improvement in packing density and makes it difficult to effectively improve battery capacity. Furthermore, if the area fraction of particles with a particle size of 1 µm or greater in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil exceeds 50%, too many large particles can cause a serious rebound phenomenon in the cathode film layer, leading to SEI film breakage and cracking, thereby increasing the risk of short circuits and impairing battery cycle performance.

[0108] The embodiments of the present application improve battery capacity by combining a stacked electrical core with a cathode film layer of lithium-containing transition metal phosphate with a specific large particle content, and furthermore by using a separator with a ceramic layer on both sides to increase the separator's stiffness. Simultaneously, the separator is used with a continuous layer having a porous structure, which has a larger bonding area and stronger bonding force, to increase the bonding effect between the separator and the cathode film, improve the density and stiffness of the internal formation of the stacked electrical core, and compensate for the lack of low external bonding force of the stacked electrical core.This reduces the risk of horizontal displacement due to the mutual extrusion of the cathode foil and the anode foil in the thickness direction during the rebound process of the electrical core, and reduces the risk of overlapping of the cathode foil and the anode foil, which in turn triggers a short circuit, in order to further improve the cycle performance of the battery based on good battery capacity.

[0109] In the present application, the stacked electrical core refers to an electrical core formed by stacking a cathode foil, a separator and an anode foil.

[0110] In the present application, the cathode film layer comprises lithium-containing transition metal phosphate particles, but the cathode film layer does not refer only to the active cathode material layer, and other film layers associated with the active cathode material layer and difficult to distinguish from it, such as the sublayer, the liquid-retaining layer and the like, are collectively referred to as the cathode film layer.

[0111] 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 X-ray diffraction (XRD) and X-ray diffraction.

[0112] 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.

[0113] 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 EM TIC 3X CP, 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 "run cyto3" to identify the particles; the particles in the image that are not identified, or not fully identified, or incorrectly identified by the software are manually marked. The particles in the image that are not identified, or not fully identified, or incorrectly identified by the software include: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.

[0114] The percentage area fraction of particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil can directly represent the ratio of the particle area in this particle size range to the total area of ​​the particles, which reflects the area of ​​the particles in this particle size range.

[0115] It is understood that in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, 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 film layer along the thickness direction of the electrode foil.

[0116] 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.

[0117] The counting procedure for the area fraction of particles with a particle size greater than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil was performed as follows: The image of the particle determination and identification was imported into the ImageJ software for analysis, and the scale was set according to the scanning electron microscope image. Using the analysis functions "Feret," "Area," "Round," and "Solidity," the particle size, area, sphericity, and roughness in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil were statistically analyzed. This was done according to the software manual (ImageJ User Guide IJ 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. 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 therefore not counted in the statistical process for particle size of the present application, and the “NaN” corresponding statistical data displayed for Area, Round, or Solidity are deleted.The sum of the area parameters of particles with a particle size greater than or equal to 1 µm and the sum of the area parameters of all particles were calculated as the area of ​​particles with a particle size greater than or equal to 1 µm and the total area of ​​the counted particles, respectively. The sum of the areas of particles with a particle size greater than or equal to 1 µm, divided by the total area of ​​the counted particles, is considered the percentage of the area occupied by particles with a particle size greater than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil.

[0118] In some embodiments, the percentage area fraction of particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is optionally 12%, 12.02%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 34.78%, 34.95%, 35%, 36%, 36.29%, 36.37%, 36.64%, 36.88%, 37%, 38%, 38.09%, 38.44%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 49.96%, 50% or any value in a range between any two of these values.

[0119] In some embodiments, the vinylidene fluoride polymer comprises one or more vinylidene fluoride homopolymers (PVDF) or a copolymer of vinylidene fluoride and hexafluoropropylene.

[0120] As in Fig.As shown in Figure 2, 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 small bonding area and a weak bonding force.

[0121] As in Fig.Figure 3 shows a schematic representation of the surface morphology of the binder layer 203 of the separator of the embodiments of the present application. The binder layer of the separator of the embodiments of the present application has a certain porous structure in its continuous structure, and the ceramic layer between the base film and the binder layer can be observed through the porous structure.It is understood that if the continuous layer with the porous structure is used as a bonding layer, it may become block-shaped due to contact with the cathode foil or the anode foil, or 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 that the bonding layer be continuous throughout the entire battery; rather, it refers to the continuous layer with a uniform porous structure at the microscopic layer level, e.g., a continuous layer with a uniform porous structure when viewed under a microscope, instead of an island-like structure.To obtain feedback on the actual morphology of the separator, sampling preferably takes place in an area of ​​the battery where there is only a weak bond between the separator's bonding layer and the cathode or anode foil. This can be achieved, for example, by sampling the separator at a point where the projection extends beyond the cathode and anode foils, or by sampling the separator near the surface of the electrode assembly. A separator sampled in this way better reflects its actual condition.

[0122] 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 island-shaped bonding layer in the prior art, thereby making the bond between the separator and the cathode film layer stronger and more uniform, and at the same time, by means of a pore structure in the bonding layer, it can combine both the lithium-ion transfer efficiency and the kinetic performance of the battery.The compression force between the electrode foils of the stacked electric core is low compared to the wound electric core in the manufacturing process of the electric core, and the lithium-containing transition metal phosphate particles with a particle size of more than or equal to 1 µm damage the SEI film and the film layer of the electrode foil during the rebound process, and the mutual compression in the thickness direction between the cathode foil and the anode foil easily leads to a relative dislocation in the horizontal direction between the cathode foil and the anode foil.The separator provided by the embodiments of the present application is provided on both sides with a ceramic layer and uses a continuous layer with a porous structure as a bonding layer, which is particularly suitable for the stacked electrical core, helping to reduce the rebound phenomenon of the stacked electrical core during long cycles and to improve the retention of battery capacity during long cycles.

[0123] The embodiments of the present application use the continuous layer with the porous structure as a bonding layer to improve the bonding force between the separator and the electrode foil while maintaining the permeability and porosity of the separator, to improve the stability of the electrode foil, to further reduce the risk of an internal short circuit due to the rebound of the electrode foil, and to improve the cycle stability of the battery.

[0124] 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).

[0125] In the present application, the ceramic layer comprises ceramic particles, wherein the ceramic particles comprise one or more of Al2O3, AlO(OH), SiO2, TiO2, MgO, CaO, ZnO2, ZrO2 and SnO2.

[0126] Ceramic particles are flame-resistant, highly hard, and not easily deformed by heat, resulting in excellent dimensional stability. The ceramic layer is applied to both sides of the base film, which helps improve battery rigidity, reduce electrode foil rebound, and decrease the likelihood of the anode film layer coming into contact with the cathode film layer and causing a short circuit during electrode foil rebound.

[0127] In some embodiments, the percentage area fraction of particles with a particle size of 1 µm-5 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%.

[0128] The area fraction of particles with a particle size of 1 µm-5 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which contributes to improving the rebound phenomenon of large particles in the electrode foil in the battery's cycling process and to improving the battery's cycle performance based on maintaining the battery's high capacity.

[0129] In some embodiments, the percentage area fraction of particles with a particle size of 1 µm-5 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-40%.

[0130] The area fraction of particles with a particle size of 1 µm-5 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil lies within the above range, which contributes to a further improvement of the rebound phenomenon in the electrode foil, which is caused by large particles in the electrode foil that tend to concentrate the voltage, and to a reduction in the probability that the anode film layer of the electrode foil comes into contact with the cathode film layer and causes short circuits, based on the maintenance of the high capacity of the battery.

[0131] In some embodiments, the one-sided thickness of the cathode film layer is 70 µm-120 µm.

[0132] As in Fig.As shown in Figure 4, the one-sided thickness H of the cathode film layer is the distance from a first surface 102a of the cathode film layer 102, facing away from the cathode collector 101, to a second surface 102b, which is opposite the first surface 102a. It should be noted that the cathode film layer comprises lithium-containing transition metal phosphate particles, but the term cathode film layer does not refer only to the active cathode material layer, and other film layers associated with the active cathode material layer and difficult to distinguish from it, such as the sublayer, the liquid-retaining layer, and the like, are collectively referred to as the cathode film layer.

[0133] The thickness of the cathode film layer can be tested according to any known method in this technical field. As an example, the thickness of the cathode film layer in the cross-sectional area of ​​the cathode foil was measured along the thickness direction using a scanning electron microscope. Three different locations are randomly selected for measurement and used as the average value for the thickness of the cathode film layer.

[0134] In some embodiments, the one-sided thickness of the cathode film layer can optionally be 70 µm, 72.34 µm, 71 µm, 72 µm, 73 µm, 74 µm, 75 µm, 76 µm, 77 µm, 78 µm, 79 µm, 80 µm, 81 µm, 82 µm, 83 µm, 83.91 µm, 84 µm, 85 µm, 86 µm, 87 µm, 88 µm, 89 µm, 90 µm, 91 µm, 91.88 µm, 92 µm, 93 µm, 94 µm, 95 µm, 96 µm, 97 µm, 98 µm, 98.93 µm, 99 µm, 100 µm, 101 µm, 102 µm, 103 µm, 104 µm, 105 µm, 105.44 µm, 105.64 µm, 105.65 µm, 105.89 µm, 106 µm, 106.21 µm, 106.34 µm, 107 µm, 108 µm, 109 µm, 110 µm, 111 µm, 112 µm, 113 µm, 114 µm, 115 µm, 116 µm, 116.09 µm, 117 µm, 118 µm, 119 µm, 120 µm or einen beliebigen Wert in einem Bereich zwischen dieser Werte.

[0135] The gram capacity of lithium-containing transition metal phosphate particles is relatively low, and research has shown that it is difficult to meet market demand when the one-sided thickness of the cathode film layer is less than 70 µm. The one-sided thickness of the cathode film layer is within the range mentioned above, which contributes to improving the battery cell's capacity.

[0136] In some embodiments, the one-sided thickness of the cathode film layer is 90 µm-120 µm.

[0137] The thickness of the cathode film layer on one side is within the range above, which contributes to a further improvement in the battery's capacity.

[0138] In some embodiments, the one-sided thickness of the cathode film layer is 100 µm-120 µm.

[0139] Increasing the thickness of the cathode film layer on one side contributes to improving the battery's capacity, and the applicant found that the phenomenon of particle rebound in the cathode film layer is more severe when the thickness of the cathode film layer on one side is greater than or equal to 100 µm. The embodiments of the present application effectively reduce the severe rebound of the thickly coated film layer in the stacked electrical core, and the battery exhibits improved cycle performance while maintaining a high capacity.

[0140] In some embodiments, such as in Fig.As shown in Figure 4, the cathode foil 10 comprises a cathode collector 101 and a cathode film layer provided on at least one side of the cathode collector 101, and the cathode film layer 102 comprises a first region 1021, wherein the first region 1021 is located on a top side of the cathode film layer 102 facing away from the cathode collector 101, wherein the distribution uniformity of particles with a particle size of more than or equal to 1 µm in the first region 1021 is 0.2%-5%, optionally 0.2%-3.5%.

[0141] In the present application, the first region of the cathode film layer refers to a region located on the upper surface of the cathode film layer facing away from the collector. For example, a region within a thickness range from the first surface 102a of the cathode film layer down to 20 µm is designated as the first region of the cathode film layer.

[0142] The uniformity of particle distribution of particles with a size greater than or equal to 1 µm in the first region can be tested using methods known in the technical field. As an example, a section of the cathode film layer is obtained along its thickness direction. This section of the first region of the cathode film layer is observed with a scanning electron microscope at a magnification of 3k using a procedure similar to that described above. This 3k-fold electron micrograph is then further observed at a magnification of 10k, with 10 non-overlapping fields of view selected and 10 scanning electron micrographs acquired. The 10 scanning electron micrographs are imported into the software ImageJ for analysis, and 10 values ​​are tested to determine the percentage area fraction of particles with sizes greater than or equal to 1 µm in each of the 10 images.The polar deviation of the 10 obtained values ​​is the uniformity of the distribution of particles with a particle size of 1 µm or greater in the first region, where the polar deviation is the difference between the maximum and minimum values ​​of the 10 values. In the first region, the larger particles are distributed more uniformly in the cathode film layer the smaller the uniformity of the distribution of particles with a particle size of 1 µm or greater.

[0143] In some embodiments, the distribution uniformity of particles with a particle size of more than or equal to 1 µm in a first region is optionally 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 1%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 1%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 1%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5% or any value in a range between any two of these values.

[0144] The degree of voltage concentration on the large particles and on the small particles in the cathode film layer differs, which is associated with the gradual release of voltage during the cycle process, leading to different degrees of rebound in the electrode.The embodiments of the present application have a certain content of large particles, and at the same time the large particles are uniformly distributed in the electrode foil, so that the extrusion pressure of the cathode film layer on the separator has a uniform distribution, thereby reducing the risk of local excessive extrusion and local blockage of the lithium ion transfer path caused by a non-uniform distribution of the large particles, which triggers an increase in peripheral current density and facilitates the precipitation of lithium, so that the battery has a good capacity based on a further improvement in the cycle performance of the battery.

[0145] In some embodiments, in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm, the median L is A50 sphericity 0.6-0.8.

[0146] The test procedure for the sphericity of particles with a particle size greater than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is as follows: Particles with a particle size greater than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil are identified according to the procedure described above in the present application, and the morphology of the particles in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is analyzed using the "Shape Description" analysis function in ImageJ. According to the software manual (ImageJ User Guide IJ 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 sphericity of the particles.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 (diameter) is to 1. Therefore, the "Round" parameter obtained from the analysis is used to characterize the sphericity of the particles. 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 this application, and the corresponding "NaN" statistical data displayed for Round are deleted.To achieve a statistically significant number of samples, at least 10 scanning electron microscope images with non-overlapping fields of view were acquired for each electrode foil. The sphericities of the at least 1000 obtained particles 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. A50 is a sphericity L-value of the particles if, in the cumulative distribution curve of the sphericity L-value, the cumulative area fraction of the vertical axis is 50%.

[0147] In some embodiments, the median is L A50the sphericity in the cumulative distribution curve of the sphericity area of ​​particles greater than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil optionally 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.705, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80 or any value in a range between two of these values.

[0148] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, and the larger particles have a better sphericity, which reduces particle bridging due to the irregular shape of the large particles, reduces the void content in the electrode foil and simultaneously reduces the voltage concentration, which is exacerbated by the irregularity of the large particles, thus reducing the rebound of the electrode foil due to voltage release during the cycle, so that the battery cell has a high capacity and its cycle performance is further improved.

[0149] 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.

[0150] In some embodiments, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L A50 sphericity 0.65-0.75.

[0151] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, which contributes to reducing the voltage concentration of the large particles, which is exacerbated by the irregularity of the large particles, thus reducing the rebound of the electrode foil due to the voltage release during the cycle, thereby improving the cycle performance of the battery.

[0152] In some embodiments, in the cumulative distribution curve of the sphericity area of ​​particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L A50 sphericity 0.67-0.75.

[0153] The median sphericity of particles with a particle size of more than or equal to 1 µm lies within the above range, which contributes to a further improvement in the voltage concentration of the large particles, reducing the rebound of the electrode foil due to voltage release during the cycle, thus further improving the cycle life of the battery cell.

[0154] In some embodiments, the median is C 50 of the degree of graphitization in the cumulative distribution curve for a graphitization C value of the cathode film layer obtained in an area scanning mode of the laser microconfocal Raman spectrometer, is greater than 0.95 and less than or equal to 1.20; where the graphitization C value I G / I D is, 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.

[0155] 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.

[0156] 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 performed along the thickness direction of the electrode foil to characterize the degree of graphitization of the cathode film layer.

[0157] The graphitization degree 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 15 80±1 00cm -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 the disorder of carbon means that there is no regular arrangement between the carbon atoms in the structure.

[0158] 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. 50 The 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 50The 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.

[0159] 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.

[0160] 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, 1.0, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 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.

[0161] In the cumulative distribution curve of the graphitization C value of the cathode film layer, obtained in an area scanning mode of the laser microconfocal Raman spectrometer, the median C lies 50of the graphitization degree within the above range, so that the pressing density of the electrode foil can be further improved, thereby reducing the proportion of large particles in the cathode film layer, which helps to reduce the rebound phenomenon of the film layer due to too many large particles, and further improves the cycle performance of the battery, based on maintaining the battery's capacity.

[0162] 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, 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.

[0163] 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. 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 evaluate the degree of density of the carbon material layer on the active cathode material. B50 is the B-value when the cumulative number fraction on the vertical axis of the curve of the cumulative distribution of coating value B is 50%.

[0164] 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.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 along the thickness direction of the electrode foil is preferably carried out to characterize the coating value of the cathode film layer.

[0165] 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; The position of the D-peak is at 1350±100cm- 1 , which is one of the characteristic peaks of carbon materials and represents defects or disordered structure in the lattice of sp 2 -hybridized carbon atoms are characterized. The excitation wavelength of 532 nm is selected during the test, and the test depth is shallow, lying only on the surface of the particles. Consequently, the carbon structure peaks show a higher intensity than the phosphate structure peaks in the cathode film layer test results obtained in the area-scanning mode of the laser microconfocal Raman spectrometer.

[0166] 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 layer on the surface of the lithium-containing transition metal phosphate particles. The denser the carbon material layer, 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.

[0167] In some embodiments, the cathode film layer further comprises a coating layer that is applied to at least a portion of the surface of the lithium-containing transition metal phosphate particles, median B 50 The coating value in the cumulative distribution curve for the coating value-B of the cathode film layer is 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 one any value within a range between two of these values.

[0168] The median B 50The coating value of the cathode film layer lies within the above range, indicating that the carbon material on the active cathode material is relatively dense and uniform. This improves the uniformity of the cathode film layer's sliding during roller pressing and reduces the phenomenon of stress concentration within the cathode film layer. Furthermore, the dense and uniform carbon material layer facilitates the sliding of large particles within the cathode film layer during the pressing process. This reduces stress concentration on these particles, decreases rebound due to stress release during the cycle, and ultimately improves the battery's cycle life.

[0169] In some embodiments, the iron dissolution rate of the cathode material is 658 ppm-1921 ppm.

[0170] The iron dissolution rate of the cathode material can be tested using methods known in the technical field. For example, 7.5 g of cathode material powder, obtained by scraping powder from a sample of the cathode film layer, are weighed out and 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 305 minutes, then rapidly aspirated with a 5 mL syringe and filtered into a test tube using a 0.45 µm orifice filter head. One mL of the supernatant is aspirated with a pipette gun 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 cathode material powder], where the volume of the solution is 50 mL and the mass of the solution used for analysis is 1 g, and the iron dissolution rate of the cathode material is calculated.

[0171] In some embodiments, the iron dissolution rate of the cathode material 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.

[0172] In some embodiments, the iron dissolution rate of the cathode material is 658 ppm-1485 ppm.

[0173] The iron dissolved in the cathode material originates primarily from the lithium-containing transition metal phosphate particles of the active cathode material. The iron dissolution rate depends on the number of lattice defects in the lithium-containing transition metal phosphate particles and on the completeness and density of the carbon material layer 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 particles, which reduces lattice corrosion in the weakly acidic environment. Conversely, the more complete and dense the carbon material layer on the surface of the active cathode material, the more inhibits the dissolution of iron ions in the weakly acidic environment.The cathode material, with an iron dissolution rate within the above range, exhibits relatively few lattice defects and has a complete and dense carbon material layer. This is conducive to improving the compression resistance and the degree of 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. This improves the rebound phenomenon of large particles due to stress concentration, thus further improving the cycle performance of the battery, based on the battery's good capacity.

[0174] 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 ist.

[0175] 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.

[0176] In some embodiments, the lithium-containing transition metal phosphate particles in the cathode film layer comprise one or more of the following materials: lithium iron phosphate, lithium manganese phosphate, lithium fluoro-substituted vanadium phosphate, lithium ferromanganese phosphate and their modified materials.

[0177] In some embodiments, the lithium-containing transition metal phosphate particles in the cathode film layer comprise one or more of the following materials: lithium iron phosphate and its doped modified materials, as well as modified coating materials.

[0178] In some embodiments, the mass content of titanium is 500 ppm-8000 ppm, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer.

[0179] In some embodiments, the mass content of titanium is 1000 ppm-3000 ppm, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer.

[0180] 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.

[0181] 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. 3500ppm, 4000ppm, 4500ppm, 5000ppm, 5500ppm, 6000ppm, 6500ppm, 7000ppm, 7500ppm, 8000ppm or any value in a range between any two of these values.

[0182] 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 particles 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 increases electrode rebound during cycling.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 titanium content 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, which reduces the stress concentration in the cathode film layer and improves the rebound phenomenon of the large particles due to the stress concentration, thus further improving the cycle performance of the battery, based on the fact that the battery has a good capacity.

[0183] Simultaneously, the doping of titanium 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 cathode 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 to enhance the battery's kinetics.

[0184] In some embodiments, the mass content of vanadium is 500 ppm-5000 ppm, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer.

[0185] 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 vanadium and its content are tested using inductively coupled plasma emission spectrometry with reference to Annex C of GB / T 33822-2017.

[0186] In some embodiments, the vanadium mass content, 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, based on the total mass of the lithium-containing transition metal phosphate particles in the anode film layer, 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. 3500ppm, 4000ppm, 4500ppm, 5000ppm or any value in a range between any two of these values.

[0187] In some embodiments, the mass content of vanadium is 500 ppm-3000 ppm, based on the total mass of the lithium-containing transition metal phosphate particles in the cathode film layer.

[0188] 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 further enhancing the kinetic and cycle performance of the battery cell.

[0189] The vanadium content in the above area contributes to improving the kinetic performance of the cathode foil and the kinetic performance of the 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 lithium-containing transition metal phosphate battery.

[0190] 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 0.2%-6%, optionally 1.5%-5%.

[0191] Based on the total area of ​​the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the total area of ​​the agglomeration region of the conductive agent lies within the above range, indicating that the conductive agent is uniformly dispersed in the cathode film layer and that it is easy to form a homogeneous conductive network, which helps to reduce local polarization or even lithium precipitation of the battery during the cycling process.

[0192] At the same time, research has shown that the lithium-containing transition metal phosphate particles of a large size are easily rebounded. The agglomeration area of ​​the conductive agent in the above area can inhibit the rebound of the lithium-containing transition metal phosphate particles by means of the uniform distribution of the conductive agent, in order to form a mechanical bond between the particles and even the film layer, improve the cohesion of the film layer, reduce the breakage of the SEI film and the film layer during the rebound process of the film layer, and extend the battery's lifespan.

[0193] The area fraction of the conductive agglomeration region, relative to the total cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, can be determined using the following procedure. 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 similar procedure described above. Since the conductive material is generally carbon-based, such as conductive carbon black, carbon nanotubes, etc., the conductive agglomeration region tends to appear as a black agglomeration compared to other areas in the cathode film layer, and the agglomerated conductive material is visible at high magnification.The agglomeration region of the conductive medium is the area of ​​black where the conductive medium is clearly aggregated in the scanning electron microscope image. Using image analysis software such as ImageJ to count the white-marked areas in the image, the regions where Feret is greater than or equal to 2 µm are filtered out. The "Feret" parameter obtained from the analysis represents the maximum distance between all parallel lines in the 2D projection of the region. The area fraction of the conductive medium agglomeration region was characterized by dividing the total area of ​​the agglomeration region of the conductive medium tested in the scanning electron microscope image at a magnification of 3k by the area of ​​the scanning electron microscope image.Three scanning electron microscope images with non-overlapping areas are taken at random and averaged as "the proportion of the total area 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".

[0194] In some embodiments, the conductive means comprises carbon nanotubes, wherein the carbon nanotubes comprise one or more of single-walled carbon nanotubes, thin-walled carbon nanotubes, multi-walled carbon nanotubes, wherein the conductive means further optionally comprises conductive carbon black.

[0195] Carbon nanotubes have a high length-to-diameter ratio, which facilitates thickness-directed overlap between a multitude of cathode particles and other particles, forming a long-distance conductive path and simultaneously improving the binding force between the particles, reducing local polarization and even lithium precipitation during the battery cycle, and improving battery life; furthermore, the binding effect reduces the rebound phenomenon of large particles in the cathode film layer, thereby improving the battery's cycle performance.

[0196] Conductive carbon black is small in size, adheres to the surface of the cathode particles, and fills the gaps between them, creating a dense, point-like conductive contact. The combination of carbon nanotubes and carbon black further enhances the conductive network within the cathode film layer, addressing both long-range and short-range conductivity. Simultaneously, the conductive material has a large specific surface area, which facilitates the absorption and retention of electrolyte solution. This reduces electrolyte extrusion, a phenomenon caused by the significant increase in electrode film expansion during extended cycles, and can thus improve battery lifespan.

[0197] In some embodiments, the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black.

[0198] 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. 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 nanotubes, and thus inhibits agglomeration, 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 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 cathode film delamination and further improving the kinetic performance and lifetime of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive medium also blocks 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.

[0199] 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%.

[0200] 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%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% or any value in a range between two of these values.

[0201] 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%, 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.

[0202] The mass content of carbon nanotubes and conductive carbon black within the above range can effectively reduce the agglomeration phenomenon of carbon nanotubes and form a good conductive network structure, thereby effectively reducing the voltage concentration of the cathode film layer and improving the retention rate of electrolyte solution of the cathode film layer during long cycles, thereby further reducing the risk of electrode foil film layer delamination and the degree of polarization, increasing the kinetic performance of the battery and improving the cycle life of the battery.

[0203] In some embodiments, the cathode film layer further comprises a dispersing agent, wherein the dispersing agent comprises hydrogenated nitrile butadiene rubber HNBR.

[0204] The polar groups (e.g., cyano group, -CN) in the HNBR hydrogenated nitrile butadiene rubber molecule 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., hydrogen bonding, dipole effect) to improve the compatibility of the particles with the solvent and to reduce the interfacial tension between the particles and the solvent, especially the interfacial tension of large particles. In this way, the particles can be dispersed more easily and uniformly in the film layer, thereby reducing aggregation due to hydrophobicity, improving the dispersion of large particles in the cathode film layer, and lowering the concentration of stresses generated during the stamping of the cathode film layer.

[0205] When the slurry is dried to form a film, the elastic network structure of HNBR can buffer the shrinkage stress generated by solvent evaporation, regroup the conductive agent in the process due to capillary action, and reduce the area fraction of the conductive agent agglomeration region, thereby improving the battery cycle life.

[0206] In some embodiments, the mass content of the dispersant is 0.5%-2%, based on the mass of the cathode film layer.

[0207] In some embodiments, the mass fraction of the dispersing agent, based on the total mass of the cathode film layer, 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%, 1.7%, 1.8%, 1.9%, 2% or any value in a range between two of these values.

[0208] 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 in the cathode film layer, and ensuring that the battery has good capacity and cycle performance.

[0209] In some embodiments, 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 3 .

[0210] 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.

[0211] The density of the cathode foil can be tested according to known methods in this 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 is then wiped off 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 compression density PD of the cathode foil is then determined. =(W1-W2) / [(T1-T2)×S].

[0212] In some embodiments, the density of the cathode foil when the battery is in a fully discharged state 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 , 2.40g / 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 , 2.50g / cm² 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 , 2.60g / cm² 3 or any value within a range between two of these values.

[0213] In some embodiments, the porosity of the cathode film layer is 14%-28%.

[0214] The porosity of the cathode film layer can be tested using the following procedure. Import the scanning electron microscope image 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 "Image" - "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.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.

[0215] 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.

[0216] The porosity of the cathode film layer lies within the above range; on the one hand, it is beneficial for improving the properties of the liquid retention of the electrolyte solution, the improvement of the ion diffusion capacity of the cathode film layer with a certain area fraction of large particles, and the improvement of the kinetic performance of the battery.

[0217] 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.

[0218] 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 the binder comprises a vinylidene fluoride polymer.

[0219] In some embodiments, the thickness of the lower coating layer is 0.5 µm-5 µm.

[0220] 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.

[0221] 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 decreasing the probability of cathode film layer delamination and improving the cycle stability of the battery. 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.

[0222] In some embodiments, the thickness of the base film in the separator is 7 µm-9 µm.

[0223] In some embodiments, the thickness of the base film in the separator is 7 µm, 7.5 µm, 8 µm, 8.5 µm, 9 µm or any value in a range between two of these values.

[0224] In some embodiments, the one-sided thickness of the ceramic layer in the separator is 2 µm-4 µm.

[0225] In some embodiments, the one-sided thickness of the ceramic layer in the separator is 2 µm, 2.5 µm, 3 µm, 3.5 µm, 4 µm or any value in a range between two of these values.

[0226] In some embodiments, the thickness of the bonding layer on one side of the separator is 1 µm-5 µm.

[0227] In some embodiments, the one-sided thickness of the bonding layer in the separator is 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.

[0228] If the thickness of the bonding layer is too small, the space for buffer expansion in the separator is limited, and the bonding force between the separator and the electrode film is weak. On the one hand, this increases the probability of elevated voltage after film expansion and delamination, impacting battery life; on the other hand, it increases the probability of a short circuit during negative cathode overlap, negatively impacting battery safety performance. Conversely, if the bonding layer thickness is too large and the battery's volumetric energy density is high, it negatively affects the battery's volumetric energy density. In the embodiments of the present application, the bonding layer thickness is within the aforementioned range, helping to balance the battery's cycle life, safety performance, and volumetric energy density.

[0229] In some embodiments, such as in Fig. Figure 5 shows that the battery cell comprises a housing 50, wherein the stacked electrical core is contained in the housing 50, wherein the housing 50 has a dimension of L0 in a longitudinal direction X, wherein the housing has a dimension of W0 in a width direction Y, wherein the housing has a dimension of H0 in a thickness direction Z, wherein 480 mm ≤ L0 ≤ 720 mm, 100 mm ≤ W0 ≤ 150 mm, 14 mm ≤ H0 ≤ 22 mm.

[0230] In some embodiments, L1 is optionally 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, 1300 mm, or any value in a range between any two of these Values.

[0231] In some embodiments, W1 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.

[0232] In some embodiments, H1 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.

[0233] The dimensions of the housing of the battery cell of the embodiments of the present application are within the above range, which contributes to achieving a better battery capacity.

[0234] In some embodiments, the dimension of the housing in the longitudinal direction L1 is 450 mm ≤ L1 ≤ 650 mm.

[0235] If the length dimension L1 of the casing meets the criteria of 450 mm ≤ L1 ≤ 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 uniformity of the electrolyte solution, further promoting the uniformity of lithium ion disembedding during the cycling process, mitigating voltage concentration, reducing the film layer rebound, and improving the cycle stability of the battery cell.

[0236] In some embodiments, the dimension of the housing in the longitudinal direction L1 is 900mm ≤ L1 ≤ 1300mm.

[0237] If the length dimension L1 of the casing meets the following condition: 900 mm ≤ L1 ≤ 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 volume energy density of the battery cell.

[0238] In some embodiments, such as in Fig. As shown in Figure 5, the material of the housing 50 is a soft packing material, wherein the soft packing material comprises an aluminum-plastic composite foil.

[0239] In some embodiments, the housing material comprises a composite film made of one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE) with aluminum.

[0240] The soft packing material has high elasticity, allowing for a thinner and softer casing, which helps improve space utilization within the battery cell and thus increase its energy density. Furthermore, the high barrier properties of aluminum effectively reduce the penetration of water and oxygen into the battery's interior, thereby minimizing electrolyte degradation and electrode material oxidation, thus extending the battery's lifespan.

[0241] In some embodiments, such as in Fig.As shown in Figure 5, the housing 50 comprises a first sealing zone 51, wherein the first sealing zone 51 is provided at at least one end of the stacked electrical core extending in the width direction (Y-direction); wherein the first sealing zone 51 comprises a folded edge structure extending in the length direction (X-direction), wherein the folded edge structure is provided with an encapsulating adhesive, wherein the encapsulating adhesive is provided successively along the length direction (X-direction) and secures the folded edge structure;

[0242] The folded edge structure is a reinforcement structure formed by an unlimited number of folds of the encapsulation area, e.g., a singly folded edge structure that is folded once, or a doubly folded edge structure that is folded on both sides.

[0243] The SEI film in the cathode film layer thickens during the electrode foil's cycling process, leading to strong rebound and gas production during long cycles. The sealing zone of the soft-packed electrical core serves to seal the electrode assembly, but this zone has limited strength and is easily washed away by the strong rebound and high gas production in the film layer.

[0244] The embodiments of the present application further improve the sealing strength of the first sealing zone by incorporating a folded edge structure extending along the longitudinal direction within the first sealing zone. The encapsulation adhesive is continuously applied along the longitudinal direction and secures the folded edge structure, in contrast to discontinuous application of the encapsulation adhesive along the longitudinal direction. This further improves the encapsulation strength, achieves continuous reinforcement of the sealing zone in the longitudinal direction, and reduces the likelihood of the electrode foil popping out of the sealing zone of the packaging during the cycle rebound process.

[0245] In some embodiments, 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 50, wherein the second sealing zone 52 is provided on one side of the electrode tab of the stacked electrical core.

[0246] 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. 5 shown, or that they may be provided on opposite sides of the stacked electrical core.

[0247] 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.

[0248] 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.

[0249] 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 directed pressure relief of the battery, reducing the effects of thermal runaway on the adjacent electrical core, and improving the overall lifespan of the battery.

[0250] 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.

[0251] The spaced arrangement of the adhesive rings in the longitudinal direction, which surround the electrical core along the lateral direction, is beneficial for fixing the position between the electrode foils in the electrical core and reducing the probability of displacement of the electrical core when the battery is shaken. This is particularly suitable for long batteries, which can effectively reduce displacement between the electrode foils in the longitudinal direction and lead to the phenomenon of lithium precipitation. It is also beneficial for keeping the internal spatial structure of the battery stable, so that it does not affect the normal operation of the battery.

[0252] In some embodiments, the battery cell capacity at 25°C is 100 Ah-300 Ah, optionally 110 Ah-190 Ah, and further optionally 125 Ah-180 Ah.

[0253] 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 at 25 °C with a charging rate of 0.5C of the nominal capacity of the battery cell to 3.65 V, then charged with a constant voltage of 3.65 V to 0.05 C and left to stand for 10 minutes, then discharged with a discharge rate of 1C to 2.5 V and left to stand for 10 minutes, and the capacity C in units of Ah is calculated during the discharge process according to the formula C=I*t.

[0254] In some embodiments, the capacity of the battery cell at 25°C can optionally be 100Ah, 125Ah, 130Ah, 135Ah, 140Ah, 145Ah, 150Ah, 155Ah, 160Ah, 165Ah, 170Ah, 175Ah, 180Ah, 185Ah, 190Ah, 300Ah or any value in a range between two of these values.

[0255] In the battery cell of the embodiments of the present application, a suitable housing dimension is set to accommodate the stacked electrical core, and an appropriate proportion of large particles in the film layer of the electrode foil in the stacked electrical core is controlled so that the battery cell has a high capacity.

[0256] 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.).

[0257] 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 a substrate made of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0258] 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.

[0259] 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).

[0260] In some embodiments, the anode film layer optionally includes further additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0261] 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, cold pressing and other processes.

[0262] A second aspect of the present application provides a battery device comprising a battery cell according to the first aspect of the present application.

[0263] 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.

[0264] 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.

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

[0266] Fig.Figure 6 shows an example of 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.

[0267] 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

[0268] 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

[0269] 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 1.02:1.0, 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;

[0270] In this case, the particle size Dv is 50 of lithium carbonate 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.

[0271] The mixed raw material was milled twice in a sand mill, with one hour of coarse milling followed by one hour of 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 0.40 µm, and spray drying was carried out to obtain a dry precursor powder whose particle size Dv50 after drying is 55.50 µm.

[0272] 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 460 °C at a heating rate of 2 °C / min (first heating stage) and held for 3 hours. The temperature was then increased from 460 °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 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 1.6 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.

[0273] The Dv10, Dv50 and Dv90 above refer to data obtained through the Malvern laser scattering test. (2) Production of the cathode foil

[0274] The above active cathode material, comprising 93.9% by mass, the conductive agent, comprising 2% by mass, and the binder polyvinylidene fluoride, comprising 3% by mass, are mixed in the solvent N-methylpyrrolidone. The dispersing agent HNBR, comprising 1.1% by mass, is then added, and the mixture is sufficiently mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. The stirring process comprises a first stirring and a second stirring, the first stirring being at a speed of 600 rpm for 30 minutes, and the second stirring being at a speed of 1600 rpm for 260 minutes. After completion of the mixing process, the cathode slurry is transferred to a coating process.wherein the mass fraction of the active cathode material, the conductive agent, the binder and the dispersant is calculated based on the total mass of the solids in the cathode slurry; The conductive agent comprises conductive carbon black with a mass fraction of 1.33% and single-walled carbon nanotubes with a mass fraction of 0.67%, wherein the conductive carbon black has a specific surface area of ​​85 m²; 2 / g and has an oil absorption value of 200 ml / 100 g and the single-walled carbon nanotubes have an average length of 30 µm, a specific surface area of ​​300 m² 2 / g and have a mass content of metallic impurities in the single-walled carbon nanotubes of <1 wt.%;

[0275] The cathode slurry is transferred to an aluminum foil of the collector for drying and coating, and after hot pressing a cathode foil with a one-sided thickness of the cathode film layer of 105.64 µm and a pressing density of 2.36 g / cm³ is produced. 3 obtained. The speed for the coating transfer is 20 m / min.

[0276] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 40 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.

[0277] The compression density here refers to the compression density when the battery cell is completely discharged, and the test procedure is described below.

[0278] The median C50 The graphitization degree of the cathode film layer is 1.005; the porosity of the cathode film layer is 16.1%; the iron dissolution rate of the cathode material is 974 ppm; the proportion of the total area of ​​the agglomeration zone of the conductive medium is 1.99%.

[0279] 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. (3) Production of the anode foil

[0280] Natural graphite, conductive carbon black, styrene-butadiene rubber (SBR) binder, and sodium carboxymethylcellulose (CMC) thickener are mixed uniformly according to a weight percentage of 95:1:2:2, deionized water is added, and then stirred and dispersed to obtain the anode slurry. 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.

[0281] 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

[0282] 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 bonding layer solution. This bonding layer solution was applied to the base film with a ceramic layer 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 bonding layer porous on both sides. The base film thickness was 8 µm, the ceramic layer thickness on one side was 3 µm, and the bonding layer thickness on the other side was 1 µm. (5) Electrolyte solution

[0283] The organic solvents dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and ethylene carbonate (EC) were thoroughly mixed in a glove box with an argon atmosphere (H2O<0.1 ppm, O2<0.1 ppm).

[0284] Lithium hexafluorophosphate was then added to dissolve the lithium hexafluorophosphate in the organic solvent, so that the concentration of lithium hexafluorophosphate is 1.05 mol / L, and vinylidene carbonate (VC) is added and stirred homogeneously to obtain the electrolyte solution of embodiment 1.

[0285] In this, based on the total mass of the electrolyte solution, the mass content of dimethyl carbonate is 26%, the mass content of methyl ethyl carbonate is 43.3%, the mass content of vinyl carbonate is 17.3% and the mass content of vinylidene carbonate is 0.9%. (6) Battery production

[0286] 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 foil wrap. The aluminum-plastic foil wrap consists of an inner layer of polypropylene, an intermediate layer of aluminum foil, and an outer layer of nylon composite. The aluminum-plastic foil wrap is formed and cut to the desired shape and size using a forming machine. The aluminum-plastic foil wrap 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, and encapsulated. Subsequently, the soft-packed batteries undergo hot and cold pressing, 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, and edge cutting. The battery cell has dimensions of 600 mm in length, 125 mm in width, and 20 mm in thickness.

[0287] 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 active cathode material and for the cathode foil is adapted as follows: Example 2

[0288] (1) Preparation of the active cathode material: Lithium dihydrogen phosphate, iron oxalate, polyethylene glycol with a weight-average molecular weight of 1000, polyethylene glycol with a weight-average molecular weight of 1500, titanium dioxide, and vanadium pentoxide are mixed uniformly in methanol and milled 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 1.02:1.0. The particle size D 10 The particle size of iron oxalate is 6.2 µm, the particle size D 50 is 60.8 µm, the particle size D 90 The particle size is 106.5 µm, and the mass content of the Fe element in the iron oxalate is 30.6%, and the mass content of trivalent iron is 0.03%.

[0289] The mixed raw material was milled several times in a ball mill and demagnetized to obtain a mixed slurry. The number of milling cycles and the milling process are controlled, as is the particle size Dv. 50 The particle size of the mixed slurry after grinding is 3.1 µm.

[0290] 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.

[0291] 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 775°C at 5°C / min and held at this temperature for 10 hours, after which it was cooled. The total mass of the active cathode material contains 1050 ppm titanium and 950 ppm volatile matter.

[0292] The obtained material was crushed by an airflow crushing process with a classification frequency of 22Hz and a crushing air pressure of 0.55 MPa to obtain an active lithium iron phosphate cathode material with the carbon material on the surface.

[0293] The above D10, D50, D90 and Dv50 refer to data obtained through the Malvern laser scattering test. (2) Production of the cathode foil

[0294] The above active cathode material, comprising 93.9% by mass, the conductive agent, comprising 2% by mass, and the binder polyvinylidene fluoride, comprising 3% by mass, are mixed in the solvent N-methylpyrrolidone. The dispersing agent HNBR, comprising 1.1% by mass, is then added, and the mixture is thoroughly mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. After completion of the mixing process, the cathode slurry is transferred to a coating process, where the mass fractions of the active cathode material, the conductive agent, the binder, and the dispersing agent are calculated based on the total mass of solids in the cathode slurry. The conductive medium comprises conductive carbon black with a mass fraction of 1.33% and single-walled carbon nanotubes with a mass fraction of 0.67%, the conductive carbon black having a specific surface area of ​​85 m². 2 / g and has an oil absorption value of 200 ml / 100 g and the single-walled carbon nanotubes have an average length of 30 µm, a specific surface area of ​​300 m² 2 / g and have a mass content of metallic impurities in the single-walled carbon nanotubes of <1 wt.%;

[0295] The cathode slurry is transferred to an aluminum foil of the collector for drying and coating, and after hot pressing a cathode foil with a one-sided thickness of the cathode film layer of 105.89 µm and a pressing density of 2.36 g / cm³ is produced. 3 obtained. Therein, the stirring comprises a pre-stirring and a main stirring, wherein the stirring speed of the pre-stirring is lower than that of the main stirring, wherein the pre-stirring has a rotational speed of 25 rpm and an internal rotational speed of 500 rpm, and wherein the pre-stirring has a stirring time of 15 minutes.

[0296] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 35 tons, 55 tons, and 75 tons; 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 heating temperature is 50°C. The pressing density here refers to the pressing density with the battery cell in a fully discharged state, and the test procedure is described below.

[0297] 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 3(1) Production of the active cathode material

[0298] 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 0.975, 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;

[0299] 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 a particle size Dv 50the mixed slurry is 0.43 µm; The mixed slurry is spray-dried to obtain a precursor powder;

[0300] The precursor powder is sintered to obtain a lithium iron phosphate cathode material, the sintering process comprising:

[0301] 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;

[0302] Grinding and mixing: Adding 0.5% of the total mass of the first sintered product's sucrose, 1% of the total mass of the first sintered product's sucrose, and 3.0% of the total mass of the first sintered product to the first sintered product; dividing into two groups for grinding (the third grinding); stopping grinding when Dv 50The particle size in the first group reaches 1.0 µm (grinding conditions: 550 rpm, grinding time: 1 hour) to obtain a first-group milled product; stop grinding when Dv 50 The particle size in the second group reaches 0.40 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 72:28 to obtain a mixed intermediate product; the mixed intermediate product is spray-dried;

[0303] 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.

[0304] 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 25 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

[0305] The above active cathode material, comprising 93.9% by mass, the conductive agent, comprising 2% by mass, and the binder polyvinylidene fluoride, comprising 3% by mass, are mixed in the solvent N-methylpyrrolidone. The dispersing agent HNBR, comprising 1.1% by mass, is then added, and the mixture is thoroughly mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. After completion of the mixing process, the cathode slurry is transferred to a coating process, where the mass fractions of the active cathode material, the conductive agent, the binder, and the dispersing agent are calculated based on the total mass of solids in the cathode slurry. The conductive medium comprises conductive carbon black with a mass fraction of 1.33% and single-walled carbon nanotubes with a mass fraction of 0.67%, the conductive carbon black having a specific surface area of ​​85 m². 2 / g and has an oil absorption value of 200 ml / 100 g and the single-walled carbon nanotubes have an average length of 30 µm, a specific surface area of ​​300 m² 2 / g and have a mass content of metallic impurities in the single-walled carbon nanotubes of <1 wt.%;

[0306] The cathode slurry is transferred to an aluminum foil of the collector for drying and coating, and after hot pressing a cathode foil with a one-sided thickness of the cathode film layer of 106.21 µm and a pressing density of 2.37g / cm³ is produced. 3 obtained. 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 tons, 55 tons, and 75 tons; 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 heating temperature is 50°C. The pressing density here refers to the pressing density with the battery cell in a fully discharged state, and the test procedure is described below.

[0308] 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 4

[0309] The manufacturing process of embodiment 4 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 4 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 765°C and the holding time being 8 hours to obtain a first sintered product.

[0310] 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 v The particle size was set to 50 µm for the particles of the first grinding group and 0.4 µm for the particles of the second grinding group. The ground particles of 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 815°C and the holding time is 10 hours.

[0311] 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.

[0312] (3) The cathode slurry is transferred to an aluminium foil of the collector for drying and coating, and after hot pressing a cathode foil with a one-sided thickness of the cathode film layer of 106.34 µm and a pressing density of 2.37g / cm³ is produced. 3 obtained. The drying temperature is 95°C and the drying rate is 2.0 m / min.

[0313] The hot pressing process comprises at least three hot rolling presses, wherein the hot rolling pressure increases sequentially and is successively 35 tons, 55 tons, and 70 tons; 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 heating temperature is 50°C. The pressing density here refers to the pressing density with the battery cell fully discharged, and the test procedure is described below. Example 5

[0314] The manufacturing process of embodiment 5 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: (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. The active cathode material, consisting of lithium iron phosphate with a carbon material on the surface, was obtained after a further increase in the intensity of the airflow milling. (2) The cathode slurry is transferred to an aluminium foil of the collector for drying and coating, and after hot pressing a cathode foil with a one-sided thickness of the cathode film layer of 105.65 µm and a pressing density of 2.36 g / cm³ is produced. 3 obtained. The speed for the coating transfer is 20 m / min.

[0315] 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.

[0316] The manufacturing process of embodiments 6 to 11 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 6

[0317] In embodiment 1, the cathode slurry was transferred to an aluminum foil of the collector for drying and coating. 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 by hot pressing; 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 7

[0318] In embodiment 1, the cathode slurry was transferred to an aluminum foil of the collector for drying and coating. 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 116.09 µm is obtained by hot pressing; 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 8

[0319] In embodiment 1, the cathode slurry was transferred to an aluminum foil of the collector for drying and coating. 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 72.34 µm is obtained by hot pressing; 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 9

[0320] In embodiment 1, the cathode slurry was transferred to an aluminum foil of the collector for drying and coating. 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 83.91 µm is obtained by hot pressing; 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 10

[0321] In embodiment 1, the cathode slurry was transferred to an aluminum foil of the collector for drying and coating. 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 98.93 µm is obtained by hot pressing; and the cathode foil has a pressing density of 2.52 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 11

[0322] The above active cathode material, comprising 93.9% by mass, the conductive agent, comprising 2% by mass, and the binder polyvinylidene fluoride, comprising 3% by mass, are mixed in the solvent N-methylpyrrolidone. The dispersing agent HNBR, comprising 1.1% by mass, is then added, and the mixture is sufficiently mixed, stirred, and dispersed in a mixing vessel to produce the cathode slurry. The stirring process comprises a first stirring and a second stirring, the first stirring being at a speed of 400 rpm for 15 minutes, and the second stirring being at a speed of 1200 rpm for 150 minutes. After completion of the stirring process, the cathode slurry is transferred to a coating process.

[0323] The manufacturing process of comparative example 1 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 1

[0324] The manufacturing process of Comparative Example 1 is essentially the same as that of Exemplary Example 1, with the difference that the sintering process of the active cathode material differs in particular as follows:

[0325] 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 500°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 a carbon material on the surface, was obtained after a further reduction in the intensity of the airflow milling.

[0326] The manufacturing process of comparative example 2 is essentially the same as that of embodiment 1, with the difference that the manufacturing process of the separator is adapted as follows:

[0327] Polyvinylidene fluoride (PVDF) and a dispersing agent are added to deionized water and stirred homogeneously. A thickening agent and an aqueous binder are added to the solution stirred above, and the mixture is placed in a sand mill and stirred homogeneously to obtain a slurry of the binder layer. The slurry of the binder layer is sprayed onto a base film with a double-sided ceramic coating, and the separator with an island-like structure of the binder layer is obtained after pre-evaporation at 80°C and drying at 90°C.

[0328] 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. Test procedure: 1. Battery cell capacity

[0329] The battery is charged at 25°C with a charging rate of 0.5 C of the nominal capacity of the battery cell to 3.65 V, then charged with a constant voltage of 3.65 V to 0.05 C and left to stand for 10 minutes, then discharged with a discharge rate of 1C to 2.5 V and left to stand for 10 minutes, and the capacity C in units of Ah is calculated during the discharge process according to the formula C=I*t. 2. Number of cycles corresponds to a drop in capacity to 90%

[0330] The battery is charged at 25°C with a charging rate of 0.5C of the nominal capacity of the battery cell to 3.65V, then charged with a constant voltage of 3.65V to 0.05C and left to stand for 10 minutes. The above single charge / discharge is one cycle until the battery capacity drops to 90% of the nominal capacity to end the test, which is recorded as the cycle count at @90% SOH. Table 1 cathode foil Battery cell capacity Ah Cycle count 1 corresponds to a drop in capacity to 90% / cycle Area fraction: Percentage of the area fraction of particles with a particle size of more than or equal to 1 µmin of a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil Cathode foil density g / cm³ 3 when the battery cell is completely discharged Median B 50 of the coating value Median L A50 the sphericity of particles with a particle size of more than or equal to 1 µmin of a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil One-sided thickness of the cathode film layer µm Implementation example 1 36,64% 2,36 0,369 0,687 105,64 160 1009 Implementation example 2 34,78% 2,36 0,446 0,673 105,89 162 1064 Implementation example 3 34,95% 2,37 0,368 0,745 106,21 162 1097 Implementation example 4 49,96% 2,37 0,456 0,72 106,34 161 967 Execution 12,02% 2,36 0,355 0,75 105,65 159 1059 -example 5 Implementation example 6 38,09% 2,36 0,368 0,67 91,88 140 957 Implementation example 7 38,44% 2,36 0,368 0,653 116,09 177 939 Implementation example 8 36,29% 2,36 0,369 0,69 72,34 110 1067 Implementation example 9 36,37% 2,36 0,369 0,688 83,91 128 1045 Implementation example 10 36,88% 2,52 0,369 0,685 98,93 159 990 Comparative example 1 55,91% 2,36 0,368 0,631 105,44 159 910 Table 2 Surface morphology of the separator's bonding layer Battery cell capacity Ah The number of cycles corresponds to a drop in capacity to 90% per cycle. Example 1 porous structure 160 1009 Comparative example 2 island-like structure 160 918

[0331] As can be seen from Tables 1 and 2, the area fraction of particles with a particle size greater than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%–50%, and the separator bonding layer is a continuous layer with a porous structure. If the bonding layer comprises a vinylidene fluoride polymer, the battery cell maintains good capacity while simultaneously reducing the risk of mutual extrusion in the thickness direction of the cathode and anode foils, which develops into a horizontal dislocation during the rebound process of the electrical core. This also reduces the probability of the cathode and anode overlapping and thus causing a short circuit, thereby improving the battery's cycle performance.

[0332] As can be seen from the comparison between embodiment 4 and embodiments 1 to 3 and 5, the area fraction of particles with a particle size of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-40%, which contributes to a further improvement of the rebound phenomenon in the electrode foil, which is caused by large particles in the electrode foil that tend to concentrate the voltage, and to a reduction in the probability that the anode film layer of the electrode foil comes into contact with the cathode film layer and causes short circuits, based on maintaining the high capacity of the battery.

[0333] As can be seen from the comparison between embodiments 8 and 9 and embodiments 6 and 7, H, the one-sided thickness of the cathode film layer, is 90 µm-120 µm, which contributes to a further improvement in the battery capacity.

[0334] As can be seen from the comparison between embodiment 7 and embodiments 1 to 6 and 8 to 10, in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil, the median L in the cumulative distribution curve of the sphericity area of ​​the particles with a particle size of more than or equal to 1 µm is A50 the sphericity 0.67 to 0.75, which further improves the voltage concentration of large particles, reduces the rebound of the electrode foil due to the voltage release during the cycle process and further improves the cycle life of the battery cell. Table 3 Percentage of surface area of ​​particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil Uniformity of the distribution of particles with a particle size of more than or equal to 1 µm in the first region Lithium-ion secondary battery cell capacity (Ah) The number of cycles corresponds to a decrease in capacity to 90% per cycle. Example 1 36,83% 3,40% 160 1009 Example 11 36,85% 4,96% 160 995

[0335] As can be seen from the comparison between embodiment 11 and embodiment 1, if the distribution uniformity of particles with a particle size of more than or equal to 1 µm in the first range is 0.2% to 3.5%, it is beneficial to reduce the risk of local excessive extrusion and local blockage of the lithium ion transfer path caused by an uneven distribution of the large particles, which triggers an increase in peripheral current density and facilitates lithium precipitation, so that the battery has good capacity based on a further improvement in the battery's cycle performance.

[0336] 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. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] GB / T 33822-2017

[0180]

Claims

Battery cell characterized in that it comprises a stacked electrical core, wherein the stacked electrical core comprises a cathode foil, an anode foil and a separator provided between the cathode foil and the anode foil; 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 a percentage area fraction of the particles with a particle size of more than or equal to 1 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%;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 side of the ceramic layer facing the cathode foil and the side 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 claim 1, characterized in that the percentage area fraction of particles with a particle size of 1 µm-5 µm in a cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil is 12%-50%, optionally 12%-40%. Battery cell according to claim 1, characterized in that the vinylidene fluoride polymer comprises one or more vinylidene fluoride homopolymers (PVDF) or a copolymer of vinylidene fluoride and hexafluoropropylene. Battery cell according to one of claims 1 to 3, characterized in that a one-sided thickness of the cathode film layer is 70 µm-120 µm, optionally 90 µm-120 µm, further optionally 100 µm-120 µm. Battery cell according to one of claims 1 to 4, characterized in that the cathode film layer comprises a first region, wherein the first region is located on a top side of the cathode film layer facing away from the cathode collector, wherein the distribution uniformity of particles with a particle size of more than or equal to 1 µm in the first region is 0.2%-5%, optionally 0.2%-3.5%. 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 of more than or equal to 1 µm in the cross-sectional area of ​​the cathode film layer along the thickness direction of the electrode foil the median LA50 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 median C50 of the graphitization degree in the cumulative distribution curve for a graphitization C value of the cathode film layer obtained in an area scanning mode of the laser microconfocal Raman spectrometer is greater than 0.95 and less than or equal to 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 7, 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, 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 of claims 1 to 8, characterized in that the iron dissolution rate of the cathode material is 658 ppm-1921 ppm, optionally 658 ppm-1485 ppm. Battery cell according to one of claims 1 to 9, 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: 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. Battery cell according to one of claims 1 to 10, 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 11, 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 12, characterized in that the cathode film layer further comprises a conductive means, wherein, with reference to a 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 0.2%-6%, optionally 1.5%-5%. Battery cell according to claim 13, characterized in that the conductive means comprises carbon nanotubes, wherein the carbon nanotubes comprise one or more of single-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 13 or 14, characterized in that the agglomeration area of ​​the conductive agent comprises carbon nanotubes and conductive carbon black. Battery cell according to claim 15, 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 16, 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 17, characterized in that the mass content of the dispersing agent is 0.5%-2% in relation to the mass of the cathode film layer. Battery cell according to one of claims 1 to 18, characterized in that, when the battery cell is in a fully discharged state, the density of the cathode foil is 2.3 g / cm3-2.6 g / cm3. Battery cell according to one of claims 1 to 19, characterized in that the porosity of the cathode film layer is 14%-28%. Battery cell according to one of claims 1 to 20, 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 21, characterized in that the separator meets at least one of the following conditions: (1) the thickness of the base film is 7 µm-9 µm; (2) the one-sided thickness of the ceramic layer is 2 µm-4 µm; (3) the one-sided thickness of the bonding layer is 1 µm-5 µm. Battery cell according to one of claims 1 to 22, characterized in that the battery cell comprises a housing, wherein the stacked electrical core is received 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. Battery cell according to claim 23, characterized in that the dimension L0 of the housing in the longitudinal direction meets the following condition: 450 mm ≤ L0 ≤ 650 mm. Battery cell according to claim 23, characterized in that the dimension L0 of the housing in the longitudinal direction meets the following condition: 900 mm ≤ L0 ≤ 1300 mm. Battery cell according to claim 23, characterized in that the housing meets at least one of the following conditions: (1) the housing material is a soft packaging material, wherein 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; (2) the housing comprises a first sealing zone, wherein the first sealing zone is provided at at least one laterally extending end of the stacked electrical core;(3) the first sealing zone comprises a longitudinally extending folded edge structure, wherein the folded edge structure is provided with an encapsulating adhesive, the encapsulating adhesive being applied successively along the longitudinal direction and securing the folded edge structure; (4) 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 extending along the longitudinal direction of the housing, wherein the second sealing zone is provided on one side of the electrode tab of the stacked electrical core. Battery cell block according to one of claims 1 to 26, characterized in that 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. Battery cell according to one of claims 1 to 27, characterized in that the capacity of the battery cell at 25°C is 100 Ah-300 Ah, optionally 110 Ah-190 Ah, further optionally 125 Ah-180 Ah. Battery device, characterized in that it comprises a battery cell according to 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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