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

Abstract

Battery cell characterized in that it comprises a laminated cell, wherein the laminated cell comprises a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises lithium-containing transition metal phosphate particles, wherein a carbon material is provided on at least one part of the surface of the lithium-containing transition metal phosphate particles; wherein the one-sided thickness of the positive electrode film layer is denoted by H and H is 70 µm to 120 µm, wherein the positive electrode film layer has a first region, the first region being located at the bottom of the positive electrode film layer near the positive electrode current collector, wherein, based on the total area of ​​the particles in cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the first particle with a particle size R1 satisfying R1 ≥ 1000 nm is 12% to 50%; where a median of sphericity L R1A1 50 in a cumulative distribution curve of a sphericity surface of the first particle, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region R1 ≥ 1000 nm is 0.6 to 0.8; where the density of the positive electrode sheet is 2.3 g / cm³ 3 up to 2.6 g / cm³ 3is the value when the battery cell is in a completely discharged state.

Description

Technical field

[0001] The present application relates to the technical field of the battery cell, in particular a battery cell, a battery device and 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 and power supply systems such as hydroelectric, thermal, wind and solar power plants, as well as in power tools, electric bicycles, electric motorcycles and electric vehicles, military equipment, aerospace and other areas.

[0003] With the doubling of market demands for the range and safety performance of power-consuming devices, the demands on battery cell capacity and safety performance are also increasing. However, achieving the aforementioned performance improvements simultaneously with existing technology is difficult, which has become a technical problem that urgently needs to be solved in this field. Content of the present invention

[0004] The present application was filed in view of the problems mentioned above, and one objective of the present application is to provide a battery cell with high capacity and good safety performance.

[0005] According to a first aspect of the present application, a battery cell is provided comprising a laminated cell, wherein the laminated cell comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector, the positive electrode film layer comprising lithium-containing transition metal phosphate particles, wherein a carbon material is provided on at least a part of the surface of the lithium-containing transition metal phosphate particles, the one-sided thickness of the positive electrode film layer being designated as H and H being 70 µm to 120 µm, the positive electrode film layer comprising a first region,wherein the first region is located on the underside of the positive electrode film layer near the positive electrode current collector, wherein, based on a total area of ​​the particles in a cross-section along the thickness direction of the electrode sheet in the first region, an area of ​​the first particle with a particle size R1 satisfying R1 ≥ 1000 nm is 12% to 50%, wherein in a cumulative distribution curve of a sphericity area of ​​the first particle with a particle size R1 satisfying R1 ≥ 1000 nm, in a cross-section along the thickness direction of the electrode sheet in the first region, a median of the sphericity L, R1A1 50 0.6 to 0.8, whereby when the battery cell is completely discharged, the compression density of the positive electrode sheet is 2.3 g / cm³ 3 up to 2.6 g / cm³ 3 amounts.

[0006] The gram capacity of lithium-containing transition metal phosphate materials is relatively low, and studies have shown that battery capacity can be difficult to meet market demand if the one-sided thickness H of the positive electrode film layer is less than 70 µm. The particles of the lithium-containing transition metal phosphate material are typically in the nanometer range in size, and the applicant has determined that to improve the compaction density of the film layer, a certain quantity of initial particles with a particle size R1 that meets the requirement R1 ≥ 1000 nm must be added to the film layer.Studies have shown that improvements in particle size distribution and density within the positive electrode film layer are limited, and battery capacity cannot be effectively improved, if the area of ​​the first particle in the positive electrode film layer with a particle size R1 ≥ 1000 nm, relative to the total cross-sectional area of ​​the particles along the thickness direction of the electrode sheet in the first region, is less than 12%. This applies when the battery cell is in a fully discharged state and the density of the positive electrode sheet is less than 2.3 g / cm³. 3If the particle size is too low, the battery cannot achieve a high capacity, and it is also difficult to achieve effective particle bonding in the positive electrode film layer, which hinders the smooth conduction of electrons and ions and increases the battery impedance. However, if the area of ​​the first particle of the positive electrode film layer with a particle size R1 that meets R1 ≥ 1000 nm, relative to the total particle cross-sectional area along the thickness direction of the electrode sheet in the first region, is more than 50%, or if the compaction density of the positive electrode sheet in the fully discharged state of the battery cell is greater than 2.6 g / cm³ 3 is or the median of the sphericity L R1A150 in the cumulative distribution curve of the sphericity area of ​​the first particle in the cross-section along the thickness direction of the electrode sheet in the first region is less than 0.6, the thick coating film layer tends to concentrate the stress on the large particles when the electrode sheet is punched, with leakage of the current collector increasing significantly after punching the electrode sheet.

[0007] This embodiment of the present application improves the battery capacity by combining the laminated cell with a thickly coated positive electrode film layer made of lithium-containing transition metal phosphate. Simultaneously, by reducing the content of large-particle lithium-containing transition metal phosphates near the current collector in the positive electrode film layer, increasing the sphericity of the large-particle lithium-containing transition metal phosphate, and reducing the compaction density of the positive electrode film layer, the voltage concentration between the positive electrode film layer and the current collector is jointly improved, and the phenomenon of the film layer of the laminated cell detaching or even falling off during the stamping process is mitigated, thereby reducing safety risks.

[0008] In each embodiment, the one-sided thickness of the positive electrode film layer is designated by H and H is 90 µm to 120 µm.

[0009] If the thickness of the positive electrode film layer on one side is within the range mentioned above, this is advantageous for further improving battery capacity.

[0010] In each embodiment, the one-sided thickness of the positive electrode film layer is designated by H and H is 100 µm to 120 µm.

[0011] A further increase in the one-sided thickness of the positive electrode film layer contributes to improving the battery capacity, however, the applicant found that with a one-sided thickness of the positive electrode film layer of at least 100 µm, the phenomenon of the exposed current collector of the positive electrode sheet is more severe, wherein in the embodiments of the present application the voltage concentration between the positive electrode film layer and the current collector is improved by reducing the content of large-scale lithium-containing transition metal phosphate near the current collector side in the positive electrode film layer, increasing the sphericity of the large-scale lithium-containing transition metal phosphate and decreasing the compaction density of the positive electrode film layer, thereby reducing the probability ofThe risk of the thick coating film layer in the positive electrode sheet detaching or even falling off during the stamping process is significantly reduced, which reduces safety risks while maintaining the higher capacity of the battery.

[0012] In each embodiment, the positive electrode film layer further comprises a conductive means, wherein the total area ratio of an agglomeration region of the conductive means, based on the total area of ​​the cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, is 0.2% to 6%, optionally 1.5% to 5%.

[0013] If, relative to the total cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, the area ratio of the agglomeration area of ​​the conductive medium lies within the above range, this indicates that the conductive medium is uniformly dispersed in the positive electrode film layer and can easily form a uniform conductive network, which in particular helps to reduce the problem of kinetic degradation caused by growth of the ion transfer path in the thick coating film layer, and to reduce local polarization and even the problem of lithium plating caused by the battery during the cycling process.

[0014] At the same time, studies have shown that the large first particles in lithium-containing transition metal phosphates tend to rebound, whereby the agglomerated area of ​​the conductive agent within the aforementioned area can suppress the rebound of the lithium-containing transition metal phosphate particles by means of the uniform distribution of the conductive agent and form mechanical bonds on the particles and even the film layer, thereby improving film layer cohesion, reducing powder loss and film layer degradation, and extending the battery cycle life.

[0015] In each embodiment, the conductive means comprises a carbon nanotube, wherein the carbon nanotube comprises one or more of the following types: a single-walled carbon nanotube, a thin-walled carbon nanotube and a multi-walled carbon nanotube; optionally, the conductive means further comprises conductive carbon black.

[0016] The carbon nanotube has a high length-to-diameter ratio, which helps to form a long-range electrical conduction path between several positive particles overlapping in the thickness direction and the negative particles, while simultaneously increasing the binding force between the particles. This serves to improve the kinetic performance of the thick-coated positive electrode film layer and reduce the problem of local polarization and even lithium plating that occurs during the battery's cycling process, thus increasing the battery's lifespan. Furthermore, the binding effect reduces the rebound of large particles in the thick coating film layer and the rebound of the thick film layer itself, thereby reducing film layer degradation.

[0017] The conductive carbon black is small in size, adheres to the surface of the positive electrode particles, and fills the gaps between them, creating a dense, point-like conductive contact. The combination of these two components addresses both long-range and short-range conductivity, further improving the conductive network within the positive electrode film layer. Simultaneously, the conductive agent has a large specific surface area, which facilitates fluid absorption and retention. This reduces electrolyte extrusion, a phenomenon caused by a significant increase in expansion forces during extended cycles of the thickly coated electrode sheet, thus extending the battery's cycle life.

[0018] In each embodiment, the agglomeration area of ​​the conductive agent comprises the carbon nanotube and the conductive carbon black.

[0019] Researchers discovered that carbon nanotubes, due to their high surface energy, tend to agglomerate, leading to uneven dispersion in the positive electrode film layer and an inability to form an effective carbon nanotube network structure. The surface energies of conductive carbon black and carbon nanotubes are relatively close and can be adsorbed onto the surface of the carbon nanotubes to form a physical barrier. This increases the resistance to agglomeration, reduces direct contact between the carbon nanotubes, and thus prevents agglomeration and improves the uniformity of the carbon nanotube distribution in the positive electrode film layer. This, in turn, contributes to improving the conductivity of the thick-coated positive electrode film layer and increasing the kinetic power of the battery.On the other hand, this contributes to exerting the binding effect of carbon nanotubes on the positive electrode film layer, reducing the risk of the thick coated positive electrode film layer deteriorating and further improving the kinetic performance and cycle life of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive medium also leads to the blocking of local ion transfer pathways in this region, whereby the combination with the conductive carbon black can improve the lithium ion transfer capacity of this region, reduce local polarization, and further enhance the cycle stability of the battery.

[0020] In each embodiment, the mass fraction C1 of the carbon nanotube, relative to the mass of the positive electrode film layer, satisfies: 0 < C1 ≤ 2.5% and the mass fraction C2 of the conductive carbon black satisfies: 0 < C1 ≤ 2.5%.

[0021] If the mass fraction of the carbon nanotube and the conductive carbon black is within the aforementioned range, the agglomeration of the carbon nanotubes can be effectively mitigated and a good conductive network structure formed, thereby effectively reducing the voltage concentration of the positive electrode film layer and improving the fluid retention rate of the positive electrode film layer during long cycles, which further reduces the risk of electrode sheet film layer deterioration and polarization degree, increases the kinetic performance of the battery and improves the battery cycle life.

[0022] In each embodiment, the positive electrode film layer further comprises a dispersant, wherein the dispersant comprises a hydrogenated nitrile rubber HNBR.

[0023] Polar groups (such as cyano, -CN) in molecules of hydrogenated nitrile rubber HNBR can interact with hydroxyl groups (-OH) or metal oxide sites on the surface of lithium-containing transition metal phosphate particles (such as hydrogen bonds, dipole effects), thereby improving particle compatibility with the solvent, reducing interfacial tension between the particles and the solvent, especially the interfacial tension of large particles, thus facilitating uniform particle dispersion, reducing aggregation caused by hydrophobicity, improving the dispersibility of large particles in the positive electrode film layer, and reducing the stress concentration that arises during the stamping process of the thick coating film layer.

[0024] At the same time, the elastic network structure of HNBR can buffer the shrinkage stress caused by solvent volatilization when a paste dries into a film, reduce the reaggregation of the conductive agent caused by capillary force in this process, decrease the area ratio of the agglomeration area of ​​the conductive agent, and improve the cycle life of the battery.

[0025] In each embodiment, the mass fraction of the dispersing agent relative to the mass of the positive electrode film layer is 0.5% to 2%.

[0026] If the mass fraction of the dispersant is within the range mentioned above, a uniform dispersion of the large particles in the positive electrode film layer can be achieved, while maintaining a high content of positive electrode active material in the positive electrode film layer. This reduces the local stress concentration caused by particle accumulation, mitigates the loosening or even detachment of the film layer of the laminated cell during the stamping process, and reduces safety risks.

[0027] In each embodiment, the lithium-containing transition metal phosphate particles in the positive electrode film layer comprise components represented by the following general formula: Li m Fe x P y O j Q qFormula I, where Q comprises one or more of the following elements: Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, C1 and Br, 0.8 ≤ m ≤ 1.15, 0.9 ≤ x ≤ 1, 0.95 ≤ y ≤ 1, 3.5 ≤ j ≤ 4, and 0 ≤ q ≤ 0.1.

[0028] In each embodiment, the lithium-containing transition metal phosphate particles comprise the element titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the titanium mass fraction is 500 ppm to 8000 ppm, optionally 1000 ppm to 3000 ppm.

[0029] When the element titanium is doped into the lithium-containing transition metal phosphate particles, the Ti-OP bond formed has a strong bonding effect, whereby, by anchoring the phosphate group, a shrinkage / expansion amplitude of a lattice during deintercalation of lithium ions is reduced, thereby inhibiting structural stress caused by a phase change, which has a positive effect on improving the cycle life of the battery, with the Ti-OP bond providing a more stable channel for lithium ion diffusion and reducing the migration energy barrier, thus contributing to an improvement in the kinetic performance of the battery.

[0030] If the mass fraction of the element titanium is within the aforementioned range, this helps to improve the lithium ion transfer rate of the positive electrode active material, improve the problem of a long ion diffusion path and poor kinetic performance caused by the thickly coated electrode sheet and the positive electrode film layer with a certain proportion of first particles, thus reducing the risk of lithium plating and improving the kinetic performance of the battery.

[0031] In each embodiment, the lithium-containing transition metal phosphate particles comprise the element vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the vanadium mass fraction is 500 ppm to 5000 ppm, optionally 500 ppm to 3000 ppm.

[0032] When the element vanadium is doped into the lithium-containing transition metal phosphate particles, it exhibits multivalent properties, and when +5-valent vanadium (V 5+ When doped into the phosphorus site, it leads to lattice distortion, an enlargement of a lithium ion diffusion channel, and an improvement in the ionic conductivity of the positive electrode active material due to its larger radius; and when +3-valent vanadium (V 3+ ) is doped into the transition metal site, the charge is compensated by lithium vacancies or interstitial oxygen to form defect energy levels, thereby improving the electronic conductivity of the positive electrode active material.

[0033] If the mass fraction of the element vanadium is within the above-mentioned range, this contributes to increasing the lithium ion transfer rate of the positive electrode active material, improving the electronic conductivity of the positive electrode active material, and further improving the kinetic performance of the battery through a synergistic effect with titanium doping.

[0034] In each embodiment, the battery cell further comprises a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the separator comprises a base film and a ceramic layer arranged on both sides of the base film, as well as an adhesive layer arranged on at least one side of the ceramic layer facing away from the base film side, wherein the adhesive layer is a continuous layer with a porous structure and the adhesive layer comprises a vinylidene fluoride polymer.

[0035] The separator provided in the present application uses a continuous layer with a porous structure as an adhesive layer, which has a larger adhesive area than an island-shaped adhesive layer of the prior art, thereby making the bonding between the separator and the positive electrode film layer stronger and more uniform, whereby the porous structure in the adhesive layer allows both the efficiency of lithium ion transfer and dynamic performance of the battery to be achieved simultaneously.Simultaneously, the compression force between the electrode sheets in the cell preparation process of laminated cells is lower compared to wound cells. The lithium-containing transition metal phosphate, which constitutes the first particle with a particle size R1 ≥ 1000 nm, reduces the tightness of the cell's internal components during the rebound process, increases cell impedance, and raises the probability of powder loss or even film delamination. The separator provided in the embodiments of the present application uses a continuous layer with a porous structure as an adhesive layer, which is particularly suitable for thick-coated laminated cells. It improves the rebound phenomenon of thick-coated laminated battery cells during long cycles and increases battery capacity retention during long cycles.Furthermore, the thickly coated laminated cell tends to experience a relative displacement between the electrode sheet and the separator when the outer electrode sheet is pulled and the electrode tab is welded, making the film layer susceptible to powder loss and even causing an overlap of the positive and negative electrodes, thus creating a risk of internal short circuits.

[0036] The embodiments of the present application use a continuous layer with a porous structure as an adhesive layer to improve the adhesive strength between the separator and the electrode sheet while maintaining the air permeability and porosity of the separator, thereby improving the stability of the electrode sheet with the thick coating film layer, further reducing the risk of powder loss or even an internal short circuit due to the relative displacement between the electrode sheet and the separator, and improving the cycle stability of the battery.

[0037] In each embodiment, the battery cell comprises an electrolyte comprising a solvent that includes ethyl methyl carbonate (EMC) and / or ethylene carbonate (EC) and dimethyl carbonate (DMC).

[0038] Dimethyl carbonate exhibits good solubility for lithium hexafluorophosphate, and the electrolyte can provide a sufficient lithium ion concentration, thus creating the necessary ion conduction conditions for the charging and discharging processes of lithium-containing transition metal phosphate batteries. Furthermore, dimethyl carbonate has a low viscosity, which can accelerate the mobility of lithium ions, increase the battery's fast-charging performance, and mitigate the disadvantages of a long ion diffusion path and reduced kinetic performance associated with thickly coated electrode sheets and positive electrode film layers containing a certain amount of first particles.

[0039] In each embodiment, the mass fraction of dimethyl carbonate, based on the total mass of the electrolyte, is 18% to 32%.

[0040] If the mass fraction of dimethyl carbonate is within the range mentioned above, the battery exhibits good fast charging performance and simultaneously improves the battery's cycle life.

[0041] In each embodiment, the total mass fraction of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) relative to the total mass of the electrolyte is 52% to 71%.

[0042] In each embodiment, the electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6), wherein the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / l to 1.2 mol / l.

[0043] In each embodiment, based on the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is 12% to 40%.

[0044] If the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is in the first range within the above-mentioned range, this is advantageous for the battery, as it further improves the voltage concentration between the positive electrode film layer and the current collector while maintaining a high capacity, which alleviates the phenomenon of the film layer of the laminated cell coming loose or even falling off during the stamping process and reduces safety risks.

[0045] In each embodiment, the median of the sphericity is L R1A2 50 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region meets 1 µm ≤ R1 ≤ 5 µm, 0.65 to 0.75.

[0046] If, in the cumulative distribution curve of the sphericity area of ​​the first particle in the cross-section along the thickness direction of the electrode sheet in the first region near the current collector side, the median of the sphericity lies within the above region, this is advantageous to further reduce the stress concentration caused by the cutting process of the thick coating film layer.

[0047] In each embodiment, the median of the sphericity is L R1A2 50 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region meets 1 µm ≤ R1 ≤ 5 µm, 0.67 to 0.75.

[0048] If the median of the sphericity L R1A2If 50 particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm are located in the first area within the above range, the voltage concentration between the positive electrode film layer and the current collector can be further improved and the cycle life of the battery cell extended.

[0049] In each embodiment, the median C in the cumulative distribution curve of the degree of graphitization, i.e., the C-value of the positive electrode film layer, obtained by the laser microconfocal Raman spectrometer in surface scanning mode, is 50 degree of graphitization greater than or equal to 0.95 and less than or equal to 1.20, where the degree of graphitization, i.e. the C value I G / I D is, where I G a G-peak intensity of the Raman spectrum at 1580 ± 100 cm⁻¹ -1 represents and I D the D peak intensity of the Raman spectrum at 1350 ± 100 cm -1 represents.

[0050] If the median C in the cumulative distribution curve of the degree of graphitization, i.e., the C value of the positive electrode film layer obtained by the laser microconfocal Raman spectrometer in surface scanning mode, is 50 Within the above range, the compaction density of the electrode sheet is further improved, allowing the content of the first particles and the thickness of the positive electrode film layer to be reduced, which helps to further decrease the probability of demolding of the positive electrode film layer while maintaining the energy density of the battery.

[0051] In each embodiment, the porosity of the positive electrode film layer is between 14% and 28%.

[0052] If the porosity of the positive electrode film layer is within the above-mentioned range, this is advantageous for improving the electrolyte retention properties, improving the ion diffusion of the thick-coated electrode sheet and the positive electrode film layer with a certain content of the first particles, and improving the dynamic performance of the battery.

[0053] In each embodiment, the positive electrode film layer in the lower region near the positive electrode current collector is provided with a primer layer, wherein the primer layer comprises a conductive agent and a binder, wherein the conductive agent comprises a carbon nanotube and a conductive carbon black, and the binder comprises a vinylidene fluoride polymer.

[0054] In each embodiment, the positive electrode film layer in the lower region near the positive electrode current collector is provided with a primer layer, wherein the primer layer has a thickness of 0.5 µm to 5 µm.

[0055] The primer layer provided in the embodiments of the present application can reduce the particle size of the particles in direct contact with the current collector, reduce the voltage concentration of the current collector at the punching position, reduce the extrusion effect of the first particle in the positive electrode film layer on the current collector during the punching process, and improve the risk of aluminum leakage in the thick coating film layer during the punching process, while simultaneously reducing the impedance of the thickly coated electrode sheet and improving the dynamic performance of the battery.

[0056] In each embodiment, the battery cell comprises a housing body, wherein the laminated cell is received in the housing body, wherein the size of the housing body in the longitudinal direction is L0, wherein the size of the housing body in the width direction is W0 and the size of the housing body in the thickness direction is H0, 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm and 14 mm ≤ H0 ≤ 22 mm.

[0057] If the size of the battery cell housing in the embodiments of the present application is within the above-mentioned range, this contributes to achieving a better battery capacity.

[0058] In each embodiment, the length L0 of the housing body in the longitudinal direction fulfills the following: 450 mm ≤ L0 ≤ 650 mm.

[0059] If the size L0 of the casing body in the longitudinal direction meets the following conditions: 450 mm ≤ L0 ≤ 650 mm, the battery cell has a shorter length, which has a positive effect on shortening the electron transfer path, reducing the internal resistance of the battery and simultaneously reducing the infiltration distance of the electrolyte into the electrode pores, thereby improving the infiltration uniformity and the dynamic performance of the thick-coated electrode sheet; in particular under fast-charging conditions, the phenomenon of uneven temperature rise and uneven current density in the longitudinal direction of the electrode sheet can be reduced.

[0060] In each embodiment, the length L0 of the housing body in the longitudinal direction satisfies the following: 900mm ≤ L0 ≤ 1300mm.

[0061] If the size L0 of the housing body in the longitudinal direction meets the following conditions: 900 mm ≤ L0 ≤ 1300 mm, the greatly enlarged battery cell size can effectively simplify a conventional module structure, enable direct integration of the battery cell into a battery pack, and allow the battery to be attached by a structural part at one end of the large surface, thereby significantly improving space utilization and increasing the overall capacity of the battery system for the same volume, while simultaneously reducing the number of structural parts and improving the energy density of the battery.

[0062] In each embodiment, the material of the housing body is a soft packaging material, wherein the soft packaging material comprises an aluminum-plastic composite film, optionally a composite film consisting of one or more of the following materials formed with aluminum: polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE).

[0063] Compared to hard casing materials such as aluminum and steel casings, soft packaging materials are lighter, which helps to further improve the energy density of the lithium-containing transition metal phosphate battery and thus increase the capacity of the battery cell.

[0064] In each embodiment, the housing body comprises a first sealing area located at at least one end of the laminated cell extending along the width direction, wherein the first sealing area comprises a fold-edge structure extending along the length direction, wherein the fold-edge structure is provided with packaging adhesive, and wherein the packaging adhesive is arranged continuously along the length direction and fixes the fold-edge structure.

[0065] In the embodiments of the present application, the sealing strength of the first sealing area is further improved by incorporating a folded edge structure extending along the longitudinal direction. Compared to a non-continuous arrangement of the encapsulating adhesive along the longitudinal direction, the continuous arrangement of the encapsulating adhesive and the attachment of the folded edge structure along the longitudinal direction can further improve the sealing and packaging strength, achieve continuous reinforcement of the sealing area in the longitudinal direction, and reduce the probability of the thick-coated electrode sheet breaking during its cycle through the sealing area in the packaging.

[0066] In each embodiment, the housing body has at least one second sealing area, wherein the second sealing area is arranged at at least one end of the laminated cell extending along the longitudinal direction of the housing body, and wherein the second sealing area is arranged on the electrode tab side of the laminated cell.

[0067] The second sealing area is located on the electrode tab side of the laminated cell, where the electrode tab must be connected to a pull-out element. The connection strength between the pull-out element and the housing body material is relatively weak, allowing gas to easily escape from the connection and thus creating a weak point for pressure relief. This contributes to directed pressure relief of the battery, reduces the impact on neighboring cells in the event of thermal misdevelopment, and improves the overall lifespan of the battery.

[0068] In each embodiment, several rubber rings are provided on the outer circumference of the laminated cell, surrounding it in the width direction, wherein the rubber rings surrounding it in the width direction are arranged at intervals along the length direction.

[0069] The longitudinal spacing of the rubber rings surrounding the cell helps to fix the positions between the electrode sheets within the cell and reduces the likelihood of cell displacement during battery vibrations. This is particularly suitable for relatively long batteries, effectively reducing the phenomenon of lithium plating caused by longitudinal displacement of the electrode sheets. This contributes to the stability of the internal structure of the battery and thus does not impair normal battery operation.

[0070] In each embodiment, the battery cell capacity at 25 °C is 100 Ah to 300 Ah, optionally 110 Ah to 190 Ah, and further optionally 125 Ah to 180 Ah.

[0071] In the embodiments of the present application, the battery cell accommodates the laminated cell by means of a suitable housing body size, wherein the proportion of large particles in the film layer of the positive electrode sheet in the laminated cell is adequately controlled, and wherein the battery cell has a relatively high capacity.

[0072] A second aspect of the present application relates to a battery device comprising the battery cell provided by the first aspect of the present application.

[0073] The third aspect of the present application provides a power-consuming device comprising the battery device provided by the second aspect of the present application, wherein the battery device is used to provide electrical energy.

[0074] The fourth aspect of the present application provides an energy storage device comprising the battery device provided by the second aspect of the present application, wherein the battery device is used to store electrical energy. Brief description of the drawing Fig. Figure 1 shows a schematic diagram of a positive electrode sheet according to an embodiment of the present application; Fig. 2 shows a scanning electron microscope image of a cross-section of a positive electrode sheet along a thickness direction at different magnification rates and an analysis diagram of an area of ​​an agglomeration region of a conductive agent in the scanning electron microscope image according to an embodiment of the present application; Fig.Figure 3 shows a schematic diagram of a separator according to (a) an embodiment of the present application and (b) the prior art, and a schematic diagram of a surface morphology of an adhesive layer of a separator according to (c) an embodiment of the present application; Fig. 4 shows a front view of a battery cell according to an embodiment of the present application; Fig. Figure 5 shows a schematic diagram of a power-consuming device according to an embodiment of the present application. Explanation of reference symbols:

[0075] 5 Battery cell; 50 Housing body; 51 First sealing area; 52 Second sealing area; 53 Extraction element; 10 Positive electrode sheet; 101 Positive current collector; 102 Positive electrode film layer; 102a First surface; 102b Second surface; 1021 First area; 20 Separator; 201 Base film; 202 Ceramic layer; 203 Adhesive layer; X Longitudinal direction; Y Width direction; Z Thickness direction. Detailed descriptions

[0076] The specific embodiments of the battery cell, battery device, current-consuming device, and energy storage device in the present application are disclosed below with due reference to the detailed description in the accompanying figures. However, an unnecessarily detailed description may be omitted. For example, a detailed description of known facts and a repeated description of essentially the same structure may be omitted. This is to avoid making the following description unnecessarily long and to facilitate understanding by the person skilled in the art. Furthermore, the drawings and the following description serve to enable the person skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0077] The “ranges” disclosed in this application are defined in the form of lower and upper limits. A specific range is defined by selecting a lower and an upper limit. The selected lower and upper limits define the boundaries of the respective range. The range thus defined can include or exclude the end values ​​and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, then ranges of 60 to 110 and 80 to 120 are also conceivable. Furthermore, if minimum range values ​​of 1 and 2 and maximum range values ​​of 3, 4, and 5 are listed, then all of the following ranges are conceivable: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5.In the present application, unless otherwise specified, a range of numbers "a to b" represents an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, the range "0 to 5" means that all real numbers between "0 to 5" are listed therein, and "0 to 5" is simply an abbreviation for these number combinations. Furthermore, if a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0078] Unless otherwise stated, all embodiments and optional embodiments of the present application may be combined to form new technical solutions, such technical solutions being considered as part of the disclosure of the present application.

[0079] Unless otherwise stated, all technical features and optional technical features of the present application may be combined to form new technical solutions, such technical solutions being considered as part of the disclosure of the present application.

[0080] Unless otherwise stated, all steps of the present application may be carried out successively or in any order, but preferably consecutively. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out consecutively, or that the method may include steps (b) and (a) carried out consecutively. For example, this means that the method may also include step (c), that step (c) may be added in any order, and the method may, for example, include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0081] In the present application, the terms "multiple" and "multiple" refer to two or more.

[0082] Unless otherwise stated, the terms used in this application have the general meanings which are usually understood by those skilled in the art.

[0083] Unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be determined using various test methods commonly used in the art, for example, they can be determined according to the test methods specified in the embodiments of this application. Unless otherwise specified, the test temperature for all parameters is 25 °C.

[0084] In one embodiment of the present application, the battery device can comprise one or more battery cell assemblies to provide the voltage and capacity. A battery cell assembly can comprise a plurality of pouch battery cells, wherein the plurality of pouch battery cells are connected in series, parallel, or mixed configuration via a busbar component. For example, a battery cell assembly is typically formed by arranging several pouch battery cells, wherein the battery cell assembly can be a battery module formed by arranging and securing several pouch battery cells to form an independent module. For example, a battery module can be formed by bundling several battery cells with cable ties.

[0085] The battery device can be a battery pack comprising a box body and one or more battery cell assemblies, wherein the battery cell assemblies are contained within the box body. The battery cell assembly can be a battery module, wherein the battery cell assembly can be contained within a box body by attaching the battery module within the box body, or wherein the battery cell assembly can also be contained within the box body by directly attaching a plurality of pouch battery cells within the box body.

[0086] In one embodiment of the present application, the box body can comprise a first box body and a second box body. The first box body and the second box body are snapped together, creating an enclosed space inside the box body for receiving the battery cell arrangement. "Enclosed" here means "covered" or "enclosed" and can be sealed or unsealed. The first box body can be a top cover or a bottom plate. For example, the box body can comprise a top cover, a frame, and a bottom plate. The top cover and the bottom plate are each connected to the frame, creating an enclosed space inside the box body for receiving the battery cell arrangement.

[0087] In one embodiment of the present application, the box body can be part of a vehicle's chassis structure. For example, part of the box body can become at least part of the vehicle's floor, or part of the box body can become at least part of a cross member and a longitudinal member of the vehicle.

[0088] In one embodiment of the present application, the battery cell can be a secondary battery that can be used continuously by activating active materials through charging after the battery cell has been discharged, wherein the battery cell can be a lithium-ion battery. The battery cell can be a flat body.

[0089] The battery mentioned in one embodiment of the present application can be a single physical module comprising one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application can comprise a battery cell, a battery module, or a battery pack.

[0090] The battery cell is the smallest unit that makes up a battery and can independently perform the functions of charging and discharging. If there are multiple battery cells, they can be connected in series, parallel, or mixed configurations via a busbar component. In some embodiments, the battery can be a battery module, where, if multiple battery cells are present, they are arranged and secured to form a single module. In some embodiments, the battery can be a battery pack comprising a housing and a battery cell, with the battery cell or battery module contained within the housing. In some embodiments, the housing can be part of a vehicle's chassis structure.For example, part of the box body can become at least part of the floor of the vehicle, or part of the box body can become at least part of a cross member and a longitudinal member of the vehicle.

[0091] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0092] In some embodiments, the battery cells can be assembled into a battery module, which can contain multiple battery cells, and the exact number of which can be adjusted 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 adjusted depending on the application and capacity of the battery pack.

[0093] The battery cell comprises an electrode array and an electrolyte.

[0094] The electrode arrangement typically comprises a positive electrode sheet and a negative electrode sheet, wherein the negative electrode sheet is an electrode that responds by absorbing or lithiating lithium ions during charging and releasing or delithiating lithium during discharging, and wherein the positive electrode sheet is an electrode that responds by releasing or delithiating lithium ions during charging and absorbing or lithiating lithium ions during discharging.

[0095] The lithium-containing transition metal phosphate material offers the advantages of high safety, long cycle life, low cost, and stable high-temperature performance. However, its gram capacity is low, which hinders improvements in battery capacity. To overcome these disadvantages, the applicant has determined that a thick coating is required in the electrode sheet construction to increase the amount of charge on the positive electrode active material in the battery and improve the energy density of the battery cell.The thick coating of the positive electrode film layer tends to cause voltage concentration in the corner regions of the wound cell, leading to powder loss or even film delamination. Furthermore, due to the presence of these corner regions, the group clearance of the wound cell is smaller than that of the laminated cell, which also negatively impacts battery capacity. Therefore, a thick coating of the positive electrode film layer in combination with a lamination design is advantageous for improving both battery capacity and stability during the cycle process.The lamination process typically includes the steps of preparing, punching, and stacking the electrode sheets. During the punching of the electrode sheet for the laminated battery, the electrode sheet is only stressed on one side compared to a wound battery. This can easily lead to microcracks, burrs, or local cracks at the edges during the punching process, resulting in exposure of the current collector. In particular, when the extrusion force of the cutter acts on the thick coating film layer, the large particles in the film layer tend to concentrate stress in the cutting area of ​​the current collector, causing the particles in the film layer to detach or even fall off, thus exposing the current collector.The lithium-containing transition metal phosphate particles often need to be sintered at high temperatures, and investigations by the applicant have shown that the sphericity of the particles decreases as the grain boundaries melt and the particles grow, with the decrease in the sphericity of the large particles further increasing the stress concentration of the large particles on the current collector, increasing the risk of current collector leakage after stamping of the electrode sheet, exacerbating a side reaction of the electrolyte in the battery and micro-short circuits within the battery, increasing the risk of battery self-discharge, worsening battery life, and even causing safety problems.Furthermore, the structure of the lithium-containing transition metal phosphate material is more stable compared to the ternary material and does not break as easily under high pressure. However, the lithium-containing transition metal phosphate particles must withstand higher pressure during an electrode sheet compaction process to achieve an increase in electrode sheet compaction density, which intensifies the stress concentration phenomenon in the electrode sheet, leading to a significantly increased risk of current collector leakage after the electrode sheet has been punched.

[0096] According to a first aspect of the present application, a battery cell is provided comprising a laminated cell, wherein the laminated cell comprises a positive electrode sheet and a negative electrode sheet, wherein as in Fig.Figure 1 shows that the positive electrode sheet 10 comprises a positive electrode current collector 101 and a positive electrode film layer 102, which is provided on at least one side of the positive electrode current collector 101, wherein the positive electrode film layer 102 comprises lithium-containing transition metal phosphate particles, wherein a carbon material is provided on at least a part of the surface of the lithium-containing transition metal phosphate particles, wherein the one-sided thickness of the positive electrode film layer 102 is designated by H and H is 70 µm to 120 µm, wherein the positive electrode film layer 102 comprises a first region 1021, the first region 1021 being located on the underside of the positive electrode film layer 102 in the vicinity of the positive electrode current collector 101.wherein, based on a total area of ​​the particles in a cross-section along the thickness direction of the electrode sheet in the first region 1021, an area of ​​the first particle with a particle size R1 that satisfies R1 ≥ 1000 nm is 12% to 50%, wherein in a cumulative distribution curve of a sphericity area of ​​the first particle with a particle size R1 that satisfies R1 ≥ 1000 nm, in a cross-section along the thickness direction of the electrode sheet in the first region 1021, a median of the sphericity L, R1A1 50 0.6 to 0.8, whereby when the battery cell is completely discharged, the compression density of the positive electrode sheet is 2.3 g / cm³ 3 up to 2.6 g / cm³ 3 amounts.

[0097] The gram capacity of lithium-containing transition metal phosphate materials is relatively low, and studies have shown that battery capacity can be difficult to meet market demand if the one-sided thickness H of the positive electrode film layer is less than 70 µm. The particles of the lithium-containing transition metal phosphate material are typically in the nanometer range in size, and the applicant has determined that to improve the compaction density of the film layer, a certain quantity of initial particles with a particle size R1 that meets the requirement R1 ≥ 1000 nm must be added to the film layer.Studies have shown that improvements in particle size distribution and density within the positive electrode film layer are limited, and battery capacity cannot be effectively improved, if the area of ​​the first particle in the positive electrode film layer with a particle size R1 ≥ 1000 nm, relative to the total cross-sectional area of ​​the particles along the thickness direction of the electrode sheet in the first region, is less than 12%. This applies when the battery cell is in a fully discharged state and the density of the positive electrode sheet is less than 2.3 g / cm³. 3If the particle size is too low, the battery cannot achieve a high capacity, and it is also difficult to achieve effective particle bonding in the positive electrode film layer, which hinders the smooth conduction of electrons and ions and increases the battery impedance. However, if the area of ​​the first particle of the positive electrode film layer with a particle size R1 that meets R1 ≥ 1000 nm, relative to the total particle cross-sectional area along the thickness direction of the electrode sheet in the first region, is more than 50%, or if the compaction density of the positive electrode sheet in the fully discharged state of the battery cell is greater than 2.6 g / cm³ 3 is or the median of the sphericity L R1A150 in the cumulative distribution curve of the sphericity area of ​​the first particle in the cross-section along the thickness direction of the electrode sheet in the first region is less than 0.6, the thick coating film layer tends to concentrate the stress on the large particles when the electrode sheet is punched, with leakage of the current collector increasing significantly after punching the electrode sheet.

[0098] It is understandable that the lithium-containing transition metal phosphate particles often need to be sintered at high temperatures, whereby the particle sphericity decreases as the grain boundaries melt and the particles grow. Based on the total particle area in the cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of particles with a particle size R1 that meets R1≥1000 nm is 12% to 50%, with the median sphericity of the first particle often not exceeding 0.8.

[0099] This embodiment of the present application improves the battery capacity by combining the laminated cell with a thickly coated positive electrode film layer made of lithium-containing transition metal phosphate. Simultaneously, by reducing the content of large-particle lithium-containing transition metal phosphates near the current collector in the positive electrode film layer, increasing the sphericity of the large-particle lithium-containing transition metal phosphate, and reducing the compaction density of the positive electrode film layer, the voltage concentration between the positive electrode film layer and the current collector is jointly improved, and the phenomenon of the film layer of the laminated cell detaching or even falling off during the stamping process is mitigated, thereby reducing safety risks.

[0100] In the present application, a laminated cell refers to a cell formed by laminating a positive electrode sheet, a separator and a negative electrode sheet.

[0101] Lithium-containing transition metal phosphate material refers to a phosphate material containing lithium and a transition metal element, and it can be detected by all methods known in the art. For example, it can be detected by combining an X-ray diffractometer (XRD) with an energy spectrum analyzer and an inductively coupled plasma mass spectrometer.

[0102] As in Fig.As shown in Figure 1, the one-sided thickness H of the positive electrode film layer refers to the distance from a first surface 102a of the positive electrode film layer 102, facing away from the positive electrode current collector 101, to a second surface 102b opposite the first surface 102a. It should be noted that the positive electrode film layer contains the lithium-containing transition metal phosphate particles. However, the term "positive electrode film layer" does not refer only to the positive electrode active material layer; other film layers that are associated with the positive electrode active material layer and are difficult to distinguish, such as the primer layer, the liquid retention layer, etc., are collectively referred to as the positive electrode film layer.

[0103] The thickness of the positive electrode film layer can be determined using all known methods. For example, the thickness of the positive electrode film layer in the cross-section of the positive electrode sheet is measured along the thickness direction using a scanning electron microscope. For the measurement, three different positions are randomly selected, and the average value is calculated as the thickness of the positive electrode film layer.

[0104] In some embodiments, the one-sided thickness H of the positive electrode film layer can 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 any range of numbers between these two values.

[0105] In some embodiments, see further below. Fig.1, the positive electrode film layer 102 comprises a first region 1021, wherein the first region 1021 is located at the bottom of the positive electrode film layer 102 in the vicinity of the positive electrode current collector 101, wherein, with respect to the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first region 1021, the area ratio of the first particle with a particle size R1 that satisfies R1 ≥ 1000 nm is 12% to 50%.

[0106] In the present application, the first region of the positive electrode film layer refers to an area located at the bottom of the positive electrode film layer near the current collector, in which the positive electrode active material is uniformly distributed. For example, if the positive electrode active material layer is deposited directly onto the surface of the positive current collector, the area from the second surface 102b of the positive electrode film layer (also the upper surface of the current collector) up to a thickness of 20 µm is defined as the first region of the positive electrode film layer.When the surface of the positive current collector is coated with the primer layer and then with the positive electrode active material, the area from the second surface 102b of the positive electrode film layer up to a thickness of 5 µm to 20 µm is recorded as the first area in order to reduce the influence of the primer layer on the test results.

[0107] In some embodiments, the first region of the positive electrode film layer is a region from the second surface 102b of the positive electrode film layer up to a thickness of 20 µm.

[0108] In some embodiments, the first region of the positive electrode film layer is a region from the second surface 102b of the positive electrode film layer to a thickness of 5 µm to 20 µm.

[0109] In the present application, the term ‘particle’ refers to particles whose complete boundaries are identifiable in the field of view of the positive electrode film layer at a certain magnification, for example 10,000x, whereby defects and scratches may be present inside the particles, but complete boundaries sufficient to separate the particles are not identifiable inside the particles.

[0110] The specific method for particle identification is as follows: The positive electrode film layer is cut along the thickness direction of the electrode sheet with an argon ion beam (for example, the instrument model: Leica EM TIC 3X CP, operating voltage: 6 kV, operating time: 6 h), and after the cross-section has been exposed, a scanning electron microscope (for example, the instrument model: Hitachi SU8230, operating voltage: 3 kV, beam current: high, probe model: U (LA100), working distance < 5 mm) is used to observe the cross-section of the positive electrode film layer along the thickness direction of the electrode sheet. Using field emission scanning electron microscopy, images in secondary electron mode are acquired at non-edge positions in the cross-section of the positive electrode film layer (after the edge of the electrode sheet has been observed under the scanning electron microscope,The field of view was set to the center of the sample, and electron microscope images were acquired at 10,000x magnification. The particles in the electron microscope images were analyzed using ImageJ software (1.46r, Win64 version). The specific method for using ImageJ is as follows: loading the scanning electron microscope images to be analyzed; using the Cellpose plug-in software to identify particles and, based on this, performing a manual correction; using ImageJ to read and count statistical data. The specific procedure for identifying particles with the Cellpose plug-in software is as follows: setting the segmentation diameter parameter (diameter in the Segmentation module) to 15 pixels; clicking "run cyto3" to perform particle identification; manually marking the particles in the image that are not identified by the software.Particles in the image that are not fully identified by the software, or are identified incorrectly, mainly include the following types: 1. The particles are too large or have scratches on their surface, preventing or preventing full detection; 2. Scratches are created on the particle surface during sectioning with the argon ion beam, and during the identification process, the software may mistakenly interpret these scratches as particle boundaries, leading to identification errors; 3. The particles are too small for successful identification; 4. The particles are located at the edge of the electron microscope's field of view, with the edge penetrating the particle's interior, preventing a complete display of its morphology and resulting in partial detection.which leads to identification errors. The aforementioned particles that are not identified or exhibit identification errors are manually calibrated, the exact procedure being as follows: Large particles at the edges of the scanning electron microscope that cannot be fully displayed are deleted; it is determined whether gap scratches are present in other particles that are not identified or exhibit identification errors, whereby if no gap scratches are present, the particles are considered as one particle and manually labeled based on the manually observed particle boundaries; whereby, in response to the presence of gap scratches, it is determined whether the gap scratches penetrate the particles, whereby if they penetrate the particles, the particles are determined as one particle and manually labeled; whereby, in response to the penetration of the gap scratches by the particles, it is determinedwhether the gap scratches are linear or irregular; in response to the irregularity of the gap scratches, they are identified as a boundary between particles and the particles are divided along this boundary; in response to the linear shape of the gap scratches, a contrast comparison is performed; in response to the unclear contrast comparison and no discernible cracks, they are designated as scratches; in response to a strong contrast comparison and a discernible crack, they are identified as a boundary between particles and designated as two particles. After manual labeling, the information irrelevant to the particles in the automatic image processing process is deleted, thus completing the assessment and labeling of the particles in the image.

[0111] In cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the first particle with a particle size R1 that satisfies R1 ≥ 1000 nm can intuitively reflect the proportional relationship between the area of ​​some particles in this particle size segment and the total area of ​​the particles, and reflect the area size of the particles in this particle size segment.

[0112] It is understandable that the particles in the cross-section along the thickness direction of the electrode sheet in the first region, in particular the particles larger than 50 nm, originate mainly from the positive electrode active material. Therefore, an embodiment of the present application can accurately and objectively reproduce the distribution of the lithium-containing transition metal phosphate particles in the first region by observing and counting the particle area in the cross-section along the thickness direction of the electrode sheet in the first region.

[0113] In the prior art, a laser particle size analyzer is generally used to count the particle size of the positive electrode active material using the Malvern laser diffraction method. However, the applicant's research shows that the lithium-containing transition metal phosphate particles tend to agglomerate, and the test results obtained with the laser scattering-based Malvern laser diffraction method are often the particle size of the particle agglomerates. This does not accurately reflect the particle size of the particles in the positive electrode active material, and even less so the dispersion state of the positive electrode active material in the film layer, since the degree of dispersion of the positive electrode active material in the film layer increases during the slurry and film rolling process.The test results obtained using the Malvern laser diffraction method are influenced by the particle size, the specific surface area, and the degree of agglomeration of the positive electrode active material, wherein, compared to the actual dispersion in the electrode sheet, the number of large particles determined in the test is lower than the actual value, while the number of small particles is higher than the actual value, and the particle size determined using the Malvern laser diffraction method therefore cannot correspond to or be analogous with the particle size statistically determined in the embodiments of the present application.

[0114] The specific test method for the area ratio of the first particle with a particle size R1 that satisfies R1 ≥ 1000 nm, in cross-section along the thickness direction of the electrode sheet in the first region, is as follows: Identifying the particles in the first region according to the method described above in the present application, importing the image after particle assessment and labeling into the ImageJ software for analysis, completing a scale setting according to the scanning electron microscope image, and using the analysis functions "Feret", "Area", "Round", and "Solidity" to perform a statistical analysis of the particle size, area, sphericity, and roughness of the particles of the positive electrode film layer in cross-section along the thickness direction of the electrode layer. According to the software manual (ImageJ User Guide IJ 1.46r), the parameter “Feret” obtained through the analysis represents a maximum distance between all parallel lines in a two-dimensional projection of the particles, thus characterizing the particle size, while the parameter “Area” represents the pixel area of ​​the particles. Since particles smaller than 50 nm exhibit large errors in the statistical process and are difficult to identify accurately, and since the particle size of the conductive agent is generally less than 50 nm, leading to large errors in the statistical results, particles smaller than 50 nm are not counted in the particle size statistics process of this application, and the particle statistics data displayed as “NaN”, corresponding to Area, Round, or Solidity, are discarded.The sum of the area parameters of particles with a particle size R1 that meets the criterion R1 ≥ 1000 nm, and the sum of the area parameters of all particles, are each taken as the area of ​​particles with a particle size R1 that meets the criterion R1 ≥ 1000 nm, and the total area of ​​the counted particles, respectively. The sum of the areas of the particles with a particle size R1 that meets the criterion R1 ≥ 1000 nm, divided by the total area of ​​the counted particles, is taken as the area ratio of the first particle with a particle size R1 that meets the criterion R1 ≥ 1000 nm, in the cross-section along the thickness direction of the electrode sheet in the first region.

[0115] In some embodiments, the area ratio of the first particle with a particle size R1 that meets R1 ≥ 1000 nm, based on the total cross-sectional area of ​​the particles along the thickness direction of the electrode sheet in the first region, can be 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 range of numbers between these two values.

[0116] In some embodiments, the median of the sphericity is L R1A1 50 in the cumulative distribution curve of the sphericity area of ​​the first particle in cross-section along the thickness direction of the electrode sheet in the first range 0.6 to 0.8.

[0117] The procedure for testing the sphericity of the first particle in cross-section along the thickness direction of the electrode sheet in the first region is as follows: Identifying the first particle in the cross-section of the first region using the method described above in the present application, and using the "Shape Description" analysis function in ImageJ to analyze the morphology of the particle in cross-section along the thickness direction of the electrode sheet in the first region. 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 major diameter as its diameter, which can be used to characterize the particle's sphericity. The closer the particle is to a sphere, the closer the ratio of the pixel area to the area of ​​the circle with the adjusted major diameter as diameter 1.Therefore, the "round" parameter of the particles obtained through analysis is used to characterize the particle's sphericity. Since particles smaller than 50 nm exhibit large errors in the statistical process and are difficult to identify accurately, and since the particle size of the conductive medium is generally less than 50 nm, leading to large errors in the statistical results, particles smaller than 50 nm are not counted in the particle size statistics process of this application, and the particle statistics data corresponding to the round, displayed as "NaN," are discarded. To achieve a statistically significant sample size, no fewer than 10 scanning electron microscope images with non-overlapping fields of view are acquired for each electrode sheet, according to the method described above.The sphericity of at least 1000 obtained first particles is arranged in ascending order from smallest to largest, and the cumulative distribution curve of the sphericity of the first particles in the first region is obtained with the sphericity as the horizontal axis and the cumulative area ratio as the vertical axis. L. R1A1 50 is the sphericity value L, which corresponds to the value when the cumulative area ratio of the vertical axis in the cumulative distribution curve of the sphericity L of the first particles is 50%.

[0118] In some embodiments, the median of the sphericity L in the cumulative distribution curve of the sphericity area of ​​the first particles in the cross-section along the thickness direction of the electrode sheet in the first region can be determined. R1A150 can be selected as 0.60, 0.61, 0.62, 0.63, 0.631, 0.64, 0.65, 0.653, 0.66, 0.67, 0.673, 0.68, 0.685, 0.687, 0.688, 0.69, 0.70, 0.705, 0.71, 0.72, 0.73, 0.74, 0.745, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80 or as any range of numbers between these two values.

[0119] A person skilled in the art can adjust the sphericity of the particle using any known method. For example, the sphericity of the particle can be adjusted by processes such as grinding, polishing, chemical etching, mechanical stirring, extrusion, coating, granulation, adding surfactants, and adjusting the parameters of each process.

[0120] In some embodiments, the compaction density of the positive electrode sheet is 2.3 g / cm³. 3 up to 2.6 g / cm³ 3 , when the battery cell is in a completely discharged state.

[0121] In the present application, the fully discharged state refers to a state obtained as follows: after placing the battery in an oven environment at 25 °C and leaving it for 2 hours, maintaining the battery temperature at 25 °C, the battery is discharged to 2.5 V with a constant current of 1 / 3 C and then discharged to 2.0 V with a constant current of 0.1 C.

[0122] The compaction density of the positive electrode sheet can be tested using methods known in the art. For example, the battery is discharged to 2.5 V with a constant current of 1 / 3 C and then discharged to 2.0 V with a constant current of 0.1 C after being placed in an oven environment at 25 °C and left to stand for 2 hours, maintaining the battery temperature at 25 °C. The battery is then disassembled to obtain the positive electrode sheet, the remaining electrolyte is treated with dimethyl carbonate solvent, the electrode sheet is dried and cut into small slices with an area of ​​S, a mass is determined as W1, and the thickness T1 of the positive electrode sheet is determined using a high-precision micrometer. The positive electrode film layer of the weighed electrode sheet is then wiped, and the mass of the current collector is weighed and recorded as W2.where the thickness T2 of the current collector is determined using a high-precision micrometer, where the compaction density of the positive electrode sheet is PD = (W1-W2) / [(T1-T2) × S].

[0123] In some embodiments, the compaction density of the positive electrode sheet can be 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 , 2.40 g / cm³ 3 , 2.41 g / cm³ 3 , 2.42 g / cm³ 3 , 2.43 g / cm³ 3 , 2.44 g / cm³ 3 , 2.45 g / cm³ 3 , 2.46 g / cm³ 3 , 2.47 g / cm³ 3 , 2.48 g / cm³ 3 , 2.49 g / cm³ 3 , 2.50 g / cm³ 3 , 2.51 g / cm³ 3 , 2.52 g / cm³ 3 , 2.53 g / cm³ 3 , 2.54 g / cm³ 3 , 2.55 g / cm³ 3 , 2.56 g / cm³ 3 , 2.57 g / cm³ 3 , 2.58 g / cm³ 3, 2.59 g / cm³ 3 , 2.60 g / cm³ 3 or can be selected as any range of numbers between these two values ​​if the battery is in a completely discharged state.

[0124] In some embodiments, the one-sided thickness of the positive electrode film layer is designated by H and H is 90 µm to 120 µm.

[0125] If the thickness of the positive electrode film layer on one side is within the range mentioned above, this is advantageous for further improving battery capacity.

[0126] In some embodiments, the one-sided thickness of the positive electrode film layer is designated by H, and H is 100 µm to 120 µm.

[0127] A further increase in the one-sided thickness of the positive electrode film layer contributes to improving the battery capacity, however, the applicant found that with a one-sided thickness of the positive electrode film layer of at least 100 µm, the phenomenon of the exposed current collector of the positive electrode sheet is more severe, wherein in the embodiments of the present application the voltage concentration between the positive electrode film layer and the current collector is improved by reducing the content of large-scale lithium-containing transition metal phosphate near the current collector side in the positive electrode film layer, increasing the sphericity of the large-scale lithium-containing transition metal phosphate and decreasing the compaction density of the positive electrode film layer, thereby reducing the probability ofThe risk of the thick coating film layer in the positive electrode sheet detaching or even falling off during the stamping process is significantly reduced, which reduces safety risks while maintaining the higher capacity of the battery.

[0128] In some embodiments, the positive electrode film layer further comprises a conductive agent, wherein the total area of ​​an agglomeration region of the conductive agent, relative to the total area of ​​the cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, is 0.2% to 6%, optionally 1.5% to 5%.

[0129] In some embodiments, the positive electrode film layer further comprises a conductive means, wherein the total area of ​​an agglomeration region of the conductive means, relative to the total area of ​​the cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, can be selected as 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%, 1.99%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 5.82%, 6%, or as any range of values ​​between these two values.

[0130] If, relative to the total cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, the total area ratio of the agglomeration area of ​​the conductive medium lies within the above range, this indicates that the conductive medium is uniformly dispersed in the positive electrode film layer and can easily form a uniform conductive network, which in particular helps to reduce the problem of kinetic degradation caused by growth of the ion transfer path in the thick coating film layer, and to reduce local polarization and even the problem of lithium plating caused by the battery during the cycling process.

[0131] At the same time, studies have shown that the large first particles in lithium-containing transition metal phosphates tend to rebound, whereby the agglomerated area of ​​the conductive agent within the aforementioned area can suppress the rebound of the lithium-containing transition metal phosphate particles by means of the uniform distribution of the conductive agent and form mechanical bonds on the particles and even the film layer, thereby improving film layer cohesion, reducing powder loss and film layer degradation, and extending the battery cycle life.

[0132] The total area ratio of the agglomeration zone of the conductive medium to the total cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet can be tested using the following method. As in Fig.As shown in Figure 2a, using a similar procedure to that described above, the cross-section of the positive electrode film layer is observed along the thickness direction of the electrode sheet with a scanning electron microscope, and the area of ​​the agglomeration region of the conductive medium in the scanning electron microscope image is measured at 3k-fold magnification. Since the conductive medium is typically a carbon-based material such as conductive carbon black or carbon nanotube, the agglomeration region of the conductive medium often appears as a black agglomerate compared to other areas of the positive electrode film layer, with the aggregated conductive medium becoming visible at high magnification, as shown in the Fig. 2b and Fig. 2c. The agglomeration area of ​​the conductive medium refers to the black area in the figures where the conductive medium is evidently aggregated. As shown in Fig.As shown in Figure 2d, the area of ​​the agglomeration region of the conductive agent is analyzed using image analysis software, for example the white highlighted area in the statistical diagram of ImageJ, wherein the area where Feret indicates a region greater than or equal to 2 µm is filtered, wherein the sum of the areas of the above-mentioned regions is a total area of ​​the agglomeration region of the conductive agent in the scanning electron microscope image, wherein the area ratio of the agglomeration region of the conductive agent is characterized by dividing the total area of ​​the agglomeration region of the conductive agent, obtained by testing in the scanning electron microscope image at 3kx magnification, by the area of ​​the scanning electron microscope image.Three non-overlapping scanning electron microscope images are selected at random, and the average value is calculated as the "total area ratio of the agglomeration area of ​​the conductive agent relative to the total area of ​​the cross-section of the positive electrode film layer along the thickness direction of the electrode sheet".

[0133] In some embodiments, the conductive means comprises a carbon nanotube, wherein the carbon nanotube comprises one or more of the following types: a single-walled carbon nanotube, a thin-walled carbon nanotube and a multi-walled carbon nanotube; optionally, the conductive means further comprises conductive carbon black.

[0134] The carbon nanotube has a high length-to-diameter ratio, which helps to form a long-range electrical conduction path between several positive particles overlapping in the thickness direction and the negative particles, while simultaneously increasing the binding force between the particles. This serves to improve the kinetic performance of the thick-coated positive electrode film layer and reduce the problem of local polarization and even lithium plating that occurs during the battery's cycling process, thus increasing the battery's lifespan. Furthermore, the binding effect reduces the rebound of large particles in the thick coating film layer and the rebound of the thick film layer itself, thereby reducing film layer degradation.

[0135] The conductive carbon black is small in size, adheres to the surface of the positive electrode particles, and fills the gaps between them, creating a dense, point-like conductive contact. The combination of these two components addresses both long-range and short-range conductivity, further improving the conductive network within the positive electrode film layer. Simultaneously, the conductive agent has a large specific surface area, which facilitates fluid absorption and retention. This reduces electrolyte extrusion, a phenomenon caused by a significant increase in expansion forces during extended cycles of the thickly coated electrode sheet, thus extending the battery's cycle life.

[0136] In some embodiments, the agglomeration area of ​​the conductive agent includes the carbon nanotube and the conductive carbon black.

[0137] Researchers discovered that carbon nanotubes, due to their high surface energy, tend to agglomerate, leading to uneven dispersion in the positive electrode film layer and an inability to form an effective carbon nanotube network structure. The surface energies of conductive carbon black and carbon nanotubes are relatively close and can be adsorbed onto the surface of the carbon nanotubes to form a physical barrier. This increases the resistance to agglomeration, reduces direct contact between the carbon nanotubes, and thus prevents agglomeration and improves the uniformity of the carbon nanotube distribution in the positive electrode film layer. This, in turn, contributes to improving the conductivity of the thick-coated positive electrode film layer and increasing the kinetic power of the battery.On the other hand, this contributes to exerting the binding effect of carbon nanotubes on the positive electrode film layer, reducing the risk of the thick coated positive electrode film layer deteriorating and further improving the kinetic performance and cycle life of the battery. Furthermore, the agglomeration of carbon nanotubes in the agglomeration region of the conductive medium also leads to the blocking of local ion transfer pathways in this region, whereby the combination with the conductive carbon black can improve the lithium ion transfer capacity of this region, reduce local polarization, and further enhance the cycle stability of the battery.

[0138] In some embodiments, the mass fraction C1 of the carbon nanotube relative to the mass of the positive electrode film layer satisfies: 0 < C1 ≤ 2.5 % and the mass fraction C2 of the conductive carbon black satisfies: 0 < C1 ≤ 2.5 %.

[0139] In some embodiments, the mass fraction C1 of the carbon nanotube, relative to the mass of the positive electrode film layer, can be selected as 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 as any range between these two values.

[0140] In some embodiments, the mass fraction C2 of the conductive carbon black, relative to the mass of the positive electrode film layer, can be selected as 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 as any range of values ​​between these two.

[0141] If the mass fraction of the carbon nanotube and the conductive carbon black is within the aforementioned range, the agglomeration of the carbon nanotubes can be effectively mitigated and a good conductive network structure formed, thereby effectively reducing the voltage concentration of the positive electrode film layer and improving the fluid retention rate of the positive electrode film layer during long cycles, which further reduces the risk of electrode sheet film layer deterioration and polarization degree, increases the kinetic performance of the battery and improves the battery cycle life.

[0142] In some embodiments, the positive electrode film layer further comprises a dispersing agent, wherein the dispersing agent comprises a hydrogenated nitrile rubber HNBR.

[0143] Polar groups (such as cyano, -CN) in molecules of hydrogenated nitrile rubber HNBR can interact with hydroxyl groups (-OH) or metal oxide sites on the surface of lithium-containing transition metal phosphate particles (such as hydrogen bonds, dipole effects), thereby improving the compatibility of the particles with the solvent, reducing the interfacial tension between the particles and the solvent, especially the interfacial tension of the large particles, thus facilitating the uniform dispersion of the particles, reducing aggregation caused by hydrophobicity, improving the dispersibility of the large particles in the positive electrode film layer, and reducing the stress concentration that arises during the stamping process of the thick coating film layer.

[0144] At the same time, the elastic network structure of HNBR can buffer the shrinkage stress caused by solvent volatilization when a paste dries into a film, reduce the reaggregation of the conductive agent caused by capillary force in this process, decrease the area ratio of the agglomeration area of ​​the conductive agent, and improve the cycle life of the battery.

[0145] In some embodiments, the mass fraction of the dispersing agent relative to the mass of the positive electrode film layer is 0.5% to 2%.

[0146] In some embodiments, the mass fraction of the dispersing agent relative to the mass of the positive electrode film layer can be selected as 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 as any range of values ​​between these two.

[0147] If the mass fraction of the dispersant is within the range mentioned above, a uniform dispersion of the large particles in the positive electrode film layer can be achieved, while maintaining a high content of positive electrode active material in the positive electrode film layer. This reduces the local stress concentration caused by particle accumulation, mitigates the loosening or even detachment of the film layer of the laminated cell during the stamping process, and reduces safety risks.

[0148] In some embodiments, the lithium-containing transition metal phosphate particles in the positive electrode film layer comprise components that are represented by the following general formula: Li m Fe x P y O j Q q Formula 1 Where Q includes one or more of the following elements: Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, C1 and Br, 0.8 ≤ m ≤ 1.15, 0.9 ≤ x ≤ 1, 0.95 ≤ y ≤ 1, 3.5 ≤ j ≤ 4 and 0 ≤ q ≤ 0.1.

[0149] In some embodiments, m can be selected as 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 as any range between these two values; x can be selected as 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0 or as any range between these two values; y can be selected as 0.95, 0.96, 0.97, 0.98, 0.99, 1.00 or as any range between these two values; j can be selected as 3.5, 3.6, 3.7, 3.8, 3.9, 4 as any range of numbers between these two values; q can be selected as 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 as any range of numbers between these two values.

[0150] In some embodiments, the lithium-containing transition metal phosphate particles comprise the element titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the titanium content is 500 ppm to 8000 ppm, optionally 1000 ppm to 3000 ppm.

[0151] In some embodiments, the element titanium is evenly distributed in the lithium-containing transition metal phosphate particles.

[0152] The types and concentrations of elements in the lithium-containing transition metal phosphate particles in the positive electrode film layer can be tested using all methods known in the art. For example, the element titanium and its concentration are tested using inductively coupled plasma optical emission spectrometry with reference to Annex C of GB / T 33822-2017.

[0153] When the element titanium is doped into the lithium-containing transition metal phosphate particles, the Ti-OP bond formed has a strong bonding effect, whereby, by anchoring the phosphate group, a shrinkage / expansion amplitude of a lattice during deintercalation of lithium ions is reduced, thereby inhibiting structural stress caused by a phase change, which has a positive effect on improving the cycle life of the battery, with the Ti-OP bond providing a more stable channel for lithium ion diffusion and reducing the migration energy barrier, thus contributing to an improvement in the kinetic performance of the battery.

[0154] If the mass fraction of the element titanium is within the aforementioned range, this helps to improve the lithium ion transfer rate of the positive electrode active material, improve the problem of a long ion diffusion path and poor kinetic performance caused by the thickly coated electrode sheet and the positive electrode film layer with a certain proportion of first particles, thus reducing the risk of lithium plating and improving the kinetic performance of the battery.

[0155] In some embodiments, the mass fraction of the element titanium, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, can be selected as 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, 5000 ppm, 5500 ppm, 6000 ppm, 6500 ppm, 7000 ppm, 7500 ppm, 8000 ppm or as any numerical range between these two values.

[0156] In some embodiments, the lithium-containing transition metal phosphate particles comprise the element vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the vanadium content is 500 ppm to 5000 ppm, optionally 500 ppm to 3000 ppm.

[0157] In some embodiments, the element vanadium is evenly distributed in the lithium-containing transition metal phosphate particles.

[0158] When the element vanadium is doped into the lithium-containing transition metal phosphate particles, it exhibits multivalent properties, and when +5-valent vanadium (V 5+ When doped into the phosphorus site, it leads to lattice distortion, an enlargement of a lithium ion diffusion channel, and an improvement in the ionic conductivity of the positive electrode active material due to its larger radius; and when +3-valent vanadium (V 3+ ) is doped into the transition metal site, the charge is compensated by lithium vacancies or interstitial oxygen to form defect energy levels, thereby improving the electronic conductivity of the positive electrode active material.

[0159] If the mass fraction of the element vanadium is within the above-mentioned range, this contributes to increasing the lithium ion transfer rate of the positive electrode active material, improving the electronic conductivity of the positive electrode active material, and further improving the kinetic performance of the battery through a synergistic effect with titanium doping.

[0160] In some embodiments, the mass fraction of the element vanadium relative to the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer can be selected as 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, 5000 ppm or as any numerical range between these two values.

[0161] In some embodiments, the lithium-containing transition metal phosphate particles in the positive electrode film layer comprise one or more of the following materials: lithium iron phosphate, lithium manganese phosphate, lithium fluorovanadium phosphate, lithium manganese iron phosphate and modified materials thereof.

[0162] In some embodiments, the lithium-containing transition metal phosphate particles in the positive electrode film layer comprise one or more of the following materials: lithium iron phosphate and its doped modified materials or coated modified materials.

[0163] In some embodiments, such as in Fig.As shown in Figure 3a, the battery cell further comprises a separator 20 arranged between the positive electrode sheet and the negative electrode sheet, the separator 20 comprising a base film 201 and a ceramic layer 202 arranged on both sides of the base film 201, as well as an adhesive layer 203 arranged on at least one side of the ceramic layer 202 facing away from the base film side 201, the adhesive layer 203 being a continuous layer with a porous structure and the adhesive layer 203 comprising a vinylidene fluoride polymer.

[0164] In some embodiments, the vinylidene fluoride polymer comprises a vinylidene fluoride homopolymer (PVDF) and a copolymer of vinylidene fluoride and other monomers, for example a copolymer of vinylidene fluoride and hexafluoropropylene.

[0165] As in Fig.As shown in Figure 3b, aqueous PVDF is frequently used as the adhesive layer of the separator in the prior art, often forming an island-like structure within the separator. This is advantageous to provide some leeway for cell expansion and to facilitate manufacturing, although the adhesive area of ​​such an adhesive layer of the separator is small and the adhesive strength is weak.

[0166] Fig.Figure 3c shows a schematic diagram of a surface morphology of an adhesive layer 203 of a separator according to an embodiment of the present application, wherein the adhesive layer of the separator in the present embodiment has a certain porous structure in its continuous structure, through which the ceramic layer arranged between the base film and the adhesive layer is visible.It is understood that if a continuous layer of the porous structure is used as an adhesive layer, it may become block-like through contact with the positive or negative electrode sheet or through forced extrusion during electrode sheet manufacturing or the circulation process, whereby the continuous layer mentioned in the present application does not require that the adhesive layer be continuous throughout the entire battery; rather, it refers to a continuous layer with a uniform porous structure at the microscopic level, such as that observed under a microscope, and not with an island-like structure.To accurately reflect the separator's morphology, samples are preferably taken from the area where the separator's adhesive layer is less strongly bonded to the positive or negative electrode sheet within the battery. For example, the sample is taken from a point on the separator where the projection extends beyond the positive or negative electrode sheet, or from the separator near the surface of the electrode assembly. A sample taken from this source better reflects the separator's true condition.

[0167] The separator provided in the present application uses a continuous layer with a porous structure as an adhesive layer, which has a larger adhesive area than an island-shaped adhesive layer of the prior art, thereby making the bonding between the separator and the positive electrode film layer stronger and more uniform, whereby the porous structure in the adhesive layer allows both the efficiency of lithium ion transfer and dynamic performance of the battery to be achieved simultaneously.Simultaneously, the compression force between the electrode sheets in the cell preparation process of laminated cells is lower compared to wound cells. The lithium-containing transition metal phosphate, which constitutes the first particle with a particle size R1 ≥ 1000 nm, reduces the tightness of the cell's internal components during the rebound process, increases cell impedance, and raises the probability of powder loss or even film delamination. The separator provided in the embodiments of the present application uses a continuous layer with a porous structure as an adhesive layer, which is particularly suitable for thick-coated laminated cells. It improves the rebound phenomenon of thick-coated laminated battery cells during long cycles and increases battery capacity retention during long cycles.Furthermore, the thickly coated laminated cell tends to experience a relative displacement between the electrode sheet and the separator when the outer electrode sheet is pulled and the electrode tab is welded, making the film layer susceptible to powder loss and even causing an overlap of the positive and negative electrodes, thus creating a risk of internal short circuits.

[0168] The embodiments of the present application use a continuous layer with a porous structure as an adhesive layer to improve the adhesive strength between the separator and the electrode sheet while maintaining the air permeability and porosity of the separator, thereby improving the stability of the electrode sheet with the thick coating film layer, further reducing the risk of powder loss or even an internal short circuit due to the relative displacement between the electrode sheet and the separator, and improving the cycle stability of the battery.

[0169] In some embodiments, the base film material may include one or more of the following materials: fiberglass, nonwoven fabric, polyethylene (PE) and polypropylene (PP).

[0170] In the present application, the ceramic layer comprises ceramic particles, wherein the ceramic particles comprise one or more of the following elements: Al2O3, AlO(OH), SiO2, TiO2, MgO, CaO, ZnO2, ZrO2 and SnO2.

[0171] The ceramic particles are flame-retardant and exhibit high hardness, making them resistant to heat deformation and thus providing excellent dimensional stability. Furthermore, the ceramic material's low thermal conductivity prevents specific thermal issues within the battery from developing into a general thermal problem, thereby improving the battery cell's safety performance.

[0172] In some embodiments, the battery cell comprises an electrolyte comprising a solvent that includes ethyl methyl carbonate (EMC) and / or ethylene carbonate (EC) and dimethyl carbonate (DMC).

[0173] Dimethyl carbonate exhibits good solubility for lithium hexafluorophosphate, and the electrolyte can provide a sufficient lithium ion concentration, thus creating the necessary ion conduction conditions for the charging and discharging processes of lithium-containing transition metal phosphate batteries. Furthermore, dimethyl carbonate has a low viscosity, which can accelerate the mobility of lithium ions, increase the battery's fast-charging performance, and mitigate the disadvantages of a long ion diffusion path and reduced kinetic performance associated with thickly coated electrode sheets and positive electrode film layers containing a certain amount of first particles.

[0174] In some embodiments, the mass fraction of dimethyl carbonate, based on the total mass of the electrolyte, is 18% to 32%.

[0175] The type and quality of the solvent and electrolyte salt in the electrolyte can be determined by testing the electrolyte using methods known to those skilled in the art. For example, the composition of the electrolyte can be determined by liquid chromatography, ultraviolet spectrophotometry, ultraviolet Vis spectrophotometry, or the like.For example, the battery cell is disassembled to obtain the free electrolyte from the battery cell, the free electrolyte from the battery cell is diluted 3 to 10 times with acetonitrile to obtain the electrolyte dilution to be tested, the above electrolyte dilution is introduced into a GC-MS 3100 gas chromatograph for organic components for a complete qualitative analysis, the temperature of the sample inlet being 250 °C, the scan range being 35 µm to 270 µm, the total ion current chromatogram of each organic substance is obtained after the test, the corresponding organic substance type is compared based on the peak position of the chromatogram and the corresponding percentage content of each organic substance is calculated based on the peak area.For example, the inorganic content in the electrolyte can be tested using an ion chromatograph (IC), whereby a quantitative electrolyte is weighed (the dilution concentration is in the middle of the standard curve) and the volume is made up to 100 mL with high-purity water, whereby the ion chromatograph is automatically sampled and tested, whereby the inorganic ion chromatogram is tested, whereby the corresponding inorganic substance type is compared based on the peak position of the chromatogram.

[0176] In some embodiments, the mass fraction of dimethyl carbonate, based on the total mass of the electrolyte, can be selected as 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, or as any range of values ​​between these two.

[0177] Since dimethyl carbonate has a low flash point, an excessively high concentration can easily lead to increased gas evolution and a reduction in battery cycle life when the electrode sheet deforms, resulting in higher internal resistance and increased heat generation. If the mass fraction of dimethyl carbonate remains within the aforementioned range, the battery will exhibit good fast-charging performance while simultaneously improving its cycle life.

[0178] In some embodiments, the total mass fraction of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) relative to the total mass of the electrolyte is 52% to 71%.

[0179] In some embodiments, the total mass fraction of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) relative to the total mass of the electrolyte can be selected as 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, or as any range of values ​​between these two.

[0180] In some embodiments, the electrolyte further comprises vinylene carbonate (VC), wherein the mass fraction of vinylene carbonate is 0.5% to 1.5% based on the total mass of the electrolyte.

[0181] Vinylene carbonate, on the surface of the negative electrode, preferentially undergoes a reduction reaction compared to other solvent components, forming a dense SEI film rich in organic lithium compounds. This SEI film exhibits high lithium-ion conductivity, which positively impacts the kinetic performance of the battery cell. Simultaneously, the SEI film possesses high mechanical strength and chemical stability, preventing continuous electrolyte decomposition and thus reducing the consumption of active lithium and gas evolution due to side reactions.

[0182] In some embodiments, the electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6), wherein the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / l to 1.2 mol / l.

[0183] In some embodiments, the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / l, 0.95 mol / l, 1.0 mol / l, 1.05 mol / l, 1.1 mol / l, 1.2 mol / l or any range of values ​​between these two.

[0184] In some embodiments, based on the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is 12% to 40%.

[0185] If the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is in the first range within the above-mentioned range, this is advantageous for the battery, as it further improves the voltage concentration between the positive electrode film layer and the current collector while maintaining a high capacity, which alleviates the phenomenon of the film layer of the laminated cell coming loose or even falling off during the stamping process and reduces safety risks.

[0186] In some embodiments, the median of the sphericity is L R1A2 50 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region meets 1 µm ≤ R1 ≤ 5 µm, 0.65 to 0.75.

[0187] If, in the cumulative distribution curve of the sphericity area of ​​the first particle in the cross-section along the thickness direction of the electrode sheet in the first region near the current collector side, the median of the sphericity lies within the above region, this is advantageous to further reduce the stress concentration caused by the cutting process of the thick coating film layer.

[0188] In some embodiments, the median of the sphericity is L R1A2 50 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region meets 1 µm ≤ R1 ≤ 5 µm, 0.67 to 0.75.

[0189] If the median of the sphericity L R1A2If 50 particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm are located in the first area within the above range, the voltage concentration between the positive electrode film layer and the current collector can be further improved and the cycle life of the battery cell extended.

[0190] In some embodiments, the median C in the cumulative distribution curve of the degree of graphitization, i.e., the C-value of the positive electrode film layer, obtained by the laser microconfocal Raman spectrometer in surface scanning mode, is 50 degree of graphitization greater than or equal to 0.95 and less than or equal to 1.20, where the degree of graphitization, i.e. the C value I G / I D is, where I G a G-peak intensity of the Raman spectrum at 1580 ± 100 cm⁻¹ -1 represents and Into the D peak intensity of the Raman spectrum at 1350 ± 100 cm -1 represents.

[0191] In the present application, the degree of graphitization, i.e., the C-value of the positive electrode film layer, can be determined by the surface scanning mode of the laser microconfocal Raman spectrometer. For example, using the laser microconfocal Raman spectrometer (high-precision Renishaw laser microconfocal Raman spectrometer), an excitation wavelength of 532 nm is selected, and a suitable amount of the positive electrode film layer is extracted to perform a surface scan on its surface or a cross-section along the thickness direction of the electrode sheet. The scan area is 45 µm × 45 µm and is divided into 10 × 10 grids, with the grid vertices being used as test points. The step size is 5 µm, and the total number of scan points is 100. This allows the determination of the C-values ​​at various locations and the cumulative distribution curve of the C-value of the surface scan area.

[0192] In the present application, the positive electrode film layer can be either a positive electrode film layer obtained by fresh manufacturing or a positive electrode film layer obtained by dismantling a battery. The surface of the positive electrode film layer obtained from battery dismantling inevitably contains electrolyte salt particle residues. To improve test accuracy, a surface scan of the cross-section of the positive electrode film layer is preferably performed along the thickness direction of the electrode sheet to characterize the degree of graphitization of the positive electrode film layer.

[0193] The degree of graphitization, i.e., the C-value of the positive electrode film layer, is determined by the ratio of the peak intensities of the G-peak (G-band) and the D-peak (D-band) of the Raman spectrum, with the position of the G-peak at 1580 ± 100 cm⁻¹ -1lies and the sp 2 -Hybrid structure of carbon characterized, with the position of the D-tip at 1350 ± 100 cm -1 lies and characterizes the disordered structure of carbon, where disorder means that there is no regular arrangement between the carbon atoms in the structure.

[0194] The cumulative distribution curve of the degree of graphitization, i.e., the C value, refers to a curve obtained by arranging at least 100 obtained C values ​​in ascending order from smallest to largest, where the degree of graphitization is the horizontal axis and the cumulative ratio of values ​​is the vertical axis. 50 The C-value corresponds to the cumulative ratio of the vertical axis in the cumulative distribution curve of the degree of graphitization, i.e., the C-value, being 50%. Compared to the point value, the median C 50The graphitization degree reflects the overall graphitization degree of the particles in the positive electrode film layer, i.e., the degree of slippage, whereby, compared to the mean value, it can reduce the influence of extreme values ​​during the test process and improve the reliability of the test results.

[0195] A person skilled in the art can adjust the degree of graphitization of the active material particle using any known method. For example, the degree of graphitization of the active material particle can be adjusted by regulating the carbon source, the sintering temperature, the sintering time, the sintering pressure, and the sintering atmosphere.

[0196] In some embodiments, the median Cso of the graphitization degree in the cumulative distribution curve of the graphitization degree, i.e., the C value of the positive electrode film layer, obtained by the laser microconfocal Raman spectrometer in surface scanning mode, can be selected as 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 as any range of values ​​between these two values.

[0197] If the median C in the cumulative distribution curve of the degree of graphitization, i.e., the C value of the positive electrode film layer obtained by the laser microconfocal Raman spectrometer in surface scanning mode, is 50Within the above range, the compaction density of the electrode sheet is further improved, allowing the content of the first particles and the thickness of the positive electrode film layer to be reduced, which helps to further decrease the probability of demolding of the positive electrode film layer while maintaining the energy density of the battery.

[0198] In some embodiments, the porosity of the positive electrode film layer is 14% to 28%.

[0199] The porosity of the positive electrode film layer can be tested as follows: Import the scanning electron microscope image of the cross-section of the positive electrode film layer, obtained as described above, along the thickness direction of the electrode sheet into the ImageJ software, select the straight line tool, mark the scale length in the image with the straight line, click on "Analyze Set Scale" and set the scale parameter in the software according to the scale length in the image.Select the rectangle tool, select the image portion outside the scale range, use "Image Duplicate" to copy the selected area, use "Image Type 8 bit" to adjust the image format, select "Analyze Set Measurements", select the following five options: "Area", "Mean gray value", "Area Fraction", "Limit to threshold", "Feret's diameter" and select 3 for "Decimal places", select "Image" - "Adjust" - "Threshold" in sequence, set the position of the "Threshold" field to 0 and 100 respectively, and then use the "Analyze-Measure" function to export the pore data in the electron microscope image of the cross-section. To export an image, use "Image" - "Overlay" - "Flatten", click "Apply" in "Threshold", then "Analyze" - "Analyze Particles", check the four columns on the left, and obtain pore statistics.

[0200] It is understandable that in one embodiment of the present application, the "pores" in the cross-section of the positive electrode film layer are identified by image color differences and threshold values. These "pores" are not the porosity data obtained in the exhaust gas test, but are primarily used to characterize the cross-sectional area between the particles in the cross-section of the positive electrode film layer. This method is superior to the exhaust gas method because the porosity obtained with the exhaust gas method is related to the pores between the particles and the pores in the carbon material on the surface of the lithium-containing transition metal phosphate, and thus cannot objectively reflect the pores between the particles.

[0201] If the porosity of the positive electrode film layer is within the above-mentioned range, this is advantageous for improving the electrolyte retention properties, improving the ion diffusion of the thick-coated electrode sheet and the positive electrode film layer with a certain content of the first particles, and improving the dynamic performance of the battery.

[0202] In some embodiments, the porosity of the positive electrode film layer can be selected as 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28% or as any range of values ​​between these two.

[0203] In some embodiments, the positive electrode film layer in the lower region near the positive electrode current collector is provided with a primer layer, wherein the primer layer comprises a conductive agent and a binder, wherein the conductive agent comprises a carbon nanotube and a conductive carbon black, and the binder comprises a vinylidene fluoride polymer.

[0204] In some embodiments, the primer layer has a thickness of 0.5 µm to 5 µm.

[0205] In some embodiments, the thickness of the primer layer can be selected as 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 as any numerical range between these two values.

[0206] The primer layer provided in the embodiments of the present application can reduce the particle size of the particles in direct contact with the current collector, reduce the voltage concentration of the current collector at the punching position, reduce the extrusion effect of the first particle in the positive electrode film layer on the current collector during the punching process, and improve the risk of aluminum leakage in the thick coating film layer during the punching process, while simultaneously reducing the impedance of the thickly coated electrode sheet and improving the dynamic performance of the battery.

[0207] In some embodiments, such as in Fig.As shown in Figure 4, the battery cell 5 comprises a housing body 50, wherein the laminated cell is contained in the housing body 50, wherein the size of the housing body 50 in the longitudinal direction (X-direction) is L0, wherein the size of the housing body in the width direction (Y-direction) is W0 and the size of the housing body in the thickness direction (Z-direction) is H0, 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm and 14 mm ≤ H0 ≤ 22 mm.

[0208] In some embodiments, L0 can be defined as 450 mm, 460 mm, 470 mm, 480 mm, 490 mm, 500 mm, 510 mm, 520 mm, 530 mm, 540 mm, 550 mm, 560 mm, 570 mm, 580 mm, 590 mm, 600 mm, 610 mm, 620 mm, 630 mm, 640 mm, 650 mm, 660 mm, 670 mm, 680 mm, 690 mm, 700 mm, 710 mm, 720 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm, 1000 mm, 1050 mm, 1100 mm, 1150 mm, 1200 mm, 1250 mm mm, 1300 mm or any range of numbers between these two values ​​can be selected.

[0209] In some embodiments, W0 can be selected as 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm or as any numerical range between these two values.

[0210] In some embodiments, H0 can be selected as 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm or as any range of numbers between these two values.

[0211] If the size of the battery cell housing in the embodiments of the present application is within the above-mentioned range, this contributes to achieving a better battery capacity.

[0212] In some embodiments, the length L0 of the housing body in the longitudinal direction fulfills the following: 450 mm ≤ L0 ≤ 650 mm.

[0213] If the size L0 of the casing body in the longitudinal direction meets the following conditions: 450 mm ≤ L0 < 650 mm, the battery cell has a shorter length, which has a positive effect on shortening the electron transfer path, reducing the internal resistance of the battery and simultaneously reducing the infiltration distance of the electrolyte into the electrode pores, thereby improving the infiltration uniformity and the dynamic performance of the thick-coated electrode sheet; in particular under fast-charging conditions, the phenomenon of uneven temperature rise and uneven current density in the longitudinal direction of the electrode sheet can be reduced.

[0214] In some embodiments, the length L0 of the housing body in the longitudinal direction satisfies the following: 900 mm ≤ L0 ≤ 1300 mm.

[0215] If the size L0 of the housing body in the longitudinal direction meets the following conditions: 900 mm ≤ L0 ≤ 1300 mm, the greatly enlarged battery cell size can effectively simplify a conventional module structure, enable direct integration of the battery cell into a battery pack, and allow the battery to be attached by a structural part at one end of the large surface, thereby significantly improving space utilization and increasing the overall capacity of the battery system for the same volume, while simultaneously reducing the number of structural parts and improving the energy density of the battery.

[0216] In some embodiments, such as in Fig.As shown in Figure 4, the material of the housing body 50 is a soft packaging material, wherein the soft packaging material comprises an aluminum-plastic composite film, optionally a composite film consisting of one or more of the following materials and formed with aluminum: polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE).

[0217] The applicant has found that, compared to hard casing materials such as aluminum and steel casings, soft packaging materials are lighter, which helps to further improve the energy density of the lithium-containing transition metal phosphate battery and thus increase the battery's capacity.

[0218] In some embodiments, see further below. Fig.4, the housing body 50 comprises a first sealing area 51, wherein the first sealing area 51 is arranged at at least one end of the laminated cell extending along the width direction (Y direction), wherein the first sealing area 51 comprises a fold-edge structure extending along the length direction (X direction), wherein the fold-edge structure is provided with packaging adhesive, and wherein the packaging adhesive is arranged continuously along the length direction (X direction) and fixes the fold-edge structure.

[0219] The folded edge structure is a reinforcement structure created by folding the sealing and packaging area in half, with no limit to the number of folds into two halves; for example, it can be a simple folded edge structure folded in half once, or a double folded edge structure folded in half on both sides.

[0220] During the electrode sheet cycle with a thick coating film layer, the SEI film thickens considerably, resulting in strong rebound and significant gas evolution during long cycles. The sealing area of ​​the pouch cell serves to seal the electrode array; however, the strength of this sealing area is limited, and there is a risk of it being breached by strong rebound and high gas evolution within the thick coating film layer.

[0221] In the embodiments of the present application, the sealing strength of the first sealing area is further improved by incorporating a folded edge structure extending along the longitudinal direction. Compared to a non-continuous arrangement of the encapsulating adhesive along the longitudinal direction, the continuous arrangement of the encapsulating adhesive and the attachment of the folded edge structure along the longitudinal direction can further improve the sealing and packaging strength, achieve continuous reinforcement of the sealing area in the longitudinal direction, and reduce the probability of the thick-coated electrode sheet breaking during its cycle through the sealing area in the packaging.

[0222] In some embodiments, the housing body has at least one second sealing area, wherein the second sealing area is arranged at at least one end of the laminated cell extending along the longitudinal direction of the housing body, and wherein the second sealing area is arranged on the electrode tab side of the laminated cell.

[0223] It is understandable that the positive electrode tab and the negative electrode tab can be arranged on the same side of the laminated cell, as in Fig. shown, or they can be arranged on different sides of the laminated cell.

[0224] In some embodiments, the battery cell 5 further comprises a pull-out element 53, wherein the pull-out element 53 is connected to the electrode tab of the battery cell, for example, the pull-out element 53 can be welded to the electrode tab, wherein the pull-out element 53 is a conductive element, wherein at least a part of the pull-out element 53 is located outside the housing body 50, wherein the pull-out element 53 serves as the electrode pull-out end of the battery cell 5, and wherein the pull-out element 53 serves for the simple electrical connection between the battery cell 5 and other battery cells 5 or other components. For example, the pull-out element 53 can have the form of a sheet.

[0225] Accordingly, the extraction element 53 also includes a positive electrode extraction element and a negative electrode extraction element, wherein the positive electrode extraction element is connected to the positive electrode tab, and wherein the negative electrode extraction element is connected to the negative electrode tab.

[0226] In some embodiments, the second sealing area is located on the electrode tab side of the laminated cell, wherein the electrode tab must be connected to a pull-out element, the connection strength between the pull-out element and the housing body material being relatively weak, which allows gas to easily escape from the connection and thus represents a weak point for pressure relief, which contributes to directed pressure relief of the battery, reduces the effect on neighboring cells in the event of thermal misdevelopment and improves the overall lifespan of the battery.

[0227] In some embodiments, several rubber rings are provided on the outer circumference of the laminated cell, surrounding it in the width direction, wherein the rubber rings surrounding it in the width direction are arranged at intervals along the length direction.

[0228] The longitudinal spacing of the rubber rings surrounding the cell helps to fix the positions between the electrode sheets within the cell and reduces the likelihood of cell displacement during battery vibrations. This is particularly suitable for relatively long batteries, effectively reducing the phenomenon of lithium plating caused by longitudinal displacement of the electrode sheets. This contributes to the stability of the internal structure of the battery and thus does not impair normal battery operation.

[0229] In some embodiments, the capacity of the battery cell at 25 °C is 100 Ah to 300 Ah, optionally 110 Ah to 190 Ah, and further optionally 125 Ah to 180 Ah.

[0230] In the present application, the capacity of a battery cell has a well-known meaning in the art and can be tested using methods known in the art. For example, charging at 25 °C with a charging rate of 0.5 C of the nominal capacity of the battery cell to 3.65 V, then charging with a constant voltage of 3.65 V to 0.05 C, resting for 10 minutes, and subsequently discharging with a discharge rate of 1 C to 2.5 V and resting for 10 minutes, whereby the capacity C during the discharge process is calculated in Ah using the formula C=I*t.

[0231] In some embodiments, the capacity of the battery cell at 25 °C can be selected as 100 Ah, 110 Ah, 125 Ah, 128 Ah, 130 Ah, 135 Ah, 140 Ah, 145 Ah, 150 Ah, 155 Ah, 159 Ah, 160 Ah, 161 Ah, 162 Ah, 165 Ah, 170 Ah, 175 Ah, 177 Ah, 180 Ah, 185 Ah, 190 Ah, 300 Ah or as any numerical range between these two values.

[0232] In the embodiments of the present application, the battery cell accommodates the laminated cell by means of a suitable housing body size, wherein the proportion of large particles in the film layer of the positive electrode sheet in the laminated cell is adequately controlled, and wherein the battery cell has a relatively high capacity.

[0233] In some embodiments, the positive electrode current collector can utilize a metal foil or a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector can comprise a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector can be formed by depositing a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0234] In some embodiments, the negative electrode current collector can use a metal foil or a composite current collector. For example, copper foil can be used as the metal foil. The composite current collector can comprise a polymer material substrate and a metal layer formed on at least one surface of the polymer base layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0235] In some embodiments, the negative electrode film layer comprises a negative electrode active material. For example, the negative electrode active material may comprise at least one of the following: 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 a negative electrode active material for a battery may also be used. These negative electrode active materials may be used alone or in combination with one or more of them.

[0236] In some embodiments, the negative electrode film layer may optionally further comprise a binder. The binder may be selected from at least one of the following substances: 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).

[0237] In some embodiments, the negative electrode film layer may optionally further comprise a conductive material. The conductive material may be selected from at least one of the following: superconducting carbon, acetylene carbon black, carbon black, Ketjen black, a carbon dot, a carbon nanotube, graphene, and a carbon nanofiber.

[0238] In some embodiments, the negative electrode film layer may optionally also include other excipients, such as a thickening agent (e.g. sodium carboxymethylcellulose (CMC-Na)).

[0239] A second aspect of the present application relates to a battery device comprising the battery cell provided by the first aspect of the present application.

[0240] The battery device disclosed in an embodiment of the present application can be used in power-consuming devices that utilize the battery device as a power source, or in various energy storage systems that use the battery device as an energy storage element. Besides vehicles, the battery device can also be used, among other things, in mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric cars, ships, spacecraft, and much more. Electric toys include, among others, stationary or mobile electric toys such as game consoles, electric toy cars, electric toy ships, and electric toy airplanes, etc., while spacecraft include, among others, airplanes, rockets, space shuttles, and spacecraft.

[0241] The present application further 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 following: a battery cell, battery module, or battery pack provided in the present application. The battery cell, battery module, or battery pack can be used as a power source for the power-consuming device and can also be used as an energy storage unit for the power-consuming device.

[0242] The power-consuming device can be selected as the battery cell, battery module or battery pack, depending on its usage requirements.

[0243] Fig.Figure 5 shows, as an example, a power-consuming device. The power-consuming device disclosed in an embodiment of the present application can be a fuel-powered vehicle, a gas-powered vehicle, or a vehicle powered by alternative energy, wherein the vehicle powered by alternative energy can be a pure electric vehicle, a hybrid vehicle, or a vehicle with extended range, etc. A battery device is arranged inside the vehicle, wherein 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 a vehicle with power; for example, the battery device can serve as an operating power source for the vehicle.The vehicle may further comprise a control unit and a motor, the control unit being used to control the battery device in order to supply power to the motor, for example, to meet the vehicle's operating power requirements during starting, navigation, and driving. In some embodiments of the present application, the battery device may not only serve as the vehicle's operating power source but also as the vehicle's propulsion power source, replacing fuel or natural gas wholly or partially to provide propulsion power for the vehicle.

[0244] In one embodiment of the present application, an energy storage device is further provided, which 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. Examples of implementation

[0245] The following are examples of embodiments of the present application. These examples are illustrative and serve only to explain the present application; they are not to be construed as limiting the present application. If no specific techniques or conditions are indicated in the examples, the techniques or conditions described in the technical literature or product instructions must be followed. The reagents and instruments used, without manufacturer information, are all commercially available products. Exemplary embodiment 1(1) Production of the positive electrode active material

[0246] Lithium carbonate, iron phosphate, titanium dioxide, vanadium pentoxide, sucrose, glucose and polyethylene glycol are added to deionized water and mixed in a premix tank, wherein the ratio of lithium carbonate and iron phosphate is such that the molar ratio of lithium to iron is 1.02:1.0 and, based on the total mass of the mixed raw materials, the mass fraction of sucrose is 2%, the mass fraction of glucose is 4% and the mass fraction of polyethylene glycol is 5%, wherein, after uniform mixing, a mixed raw material with a solids content of 38% is obtained; where the particle size Dv 50of lithium carbonate 6 µm, wherein the morphology of iron phosphate particles is spherical, wherein titanium dioxide and vanadium pentoxide are both nanoparticles, wherein the purity of sucrose is ≥ 98%, the water content of glucose is < 0.5%, and the weight average molecular weight of polyethylene glycol is 1500.

[0247] The mixed raw materials are ground twice in a sand mill, coarsely for one hour and then finely ground, whereby during the grinding process the paste temperature is regulated to below 40 degrees Celsius in order to obtain a mixed paste, wherein the particle size Dv50 of the solid particles in the mixed paste is 0.40 µm, wherein after spray drying a dry precursor powder is obtained, wherein the particle size Dv50 after drying is 55.50 µm.

[0248] The precursor powder is sintered in a nitrogen atmosphere in two temperature rise stages to obtain the positive electrode active material: The temperature is increased from 25 °C to 460 °C at a rate of 2 °C / min (first temperature rise stage) and held for 3 hours. In the second temperature rise stage, the temperature is increased from 460 °C to 780 °C at a rate of 5 °C / min and held for 12 hours. The aeration volume in the temperature rise stage is larger than in the constant temperature stage, with a ratio of 1.5:1, resulting in a total aeration volume of 1350 cm³. 3 / h, wherein the temperature is lowered after termination, wherein the powder is pulverized by an air stream to obtain a positive electrode active material with a particle size Dv50 of 1.6 µm and a carbon material on the surface, wherein, based on the total mass of the positive electrode active material, the mass fraction of the Ti element is 1050 ppm and the mass fraction of the V element is 950 ppm.

[0249] The above-mentioned Dv10, Dv50 and Dv90 refer to the data obtained using the Malvern laser diffraction method. (2) Production of the positive electrode sheet

[0250] The above-mentioned positive electrode active material with a mass fraction of 93.9%, the conductive agent with a mass fraction of 2%, and the polyvinylidene fluoride binder with a mass fraction of 3% are mixed in an N-methylpyrrolidone solvent, then the HNBR dispersing agent with a mass fraction of 1.1% is added, and the mixture is thoroughly mixed, stirred, and dispersed in a stirred tank to produce a positive electrode paste, with the positive electrode paste being transported to a coating process after completion of the stirring process;wherein the mass fractions of the positive electrode active material, the conductive agent, the binder and the dispersant are calculated based on the total mass of the solids in the positive electrode paste, wherein the conductive agent comprises a conductive carbon black with a mass fraction of 1.33% and a single-walled carbon nanotube with a mass fraction of 0.67%, wherein the specific surface area of ​​the conductive carbon black is 85 m²; 2 / g, the oil absorption value 200 ml / 100 g, the average length of the single-walled carbon nanotube 30 µm, the specific surface area 300 m² 2 / g and the mass fraction of metal impurities in the single-walled carbon nanotube is < 1%; wherein the positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, wherein after hot pressing a positive electrode sheet with a one-sided thickness of the positive electrode film layer of 105.64 µm and a compaction density of 2.36 g / cm³ 3 The transfer and coating speed is 20 m / min.

[0251] The hot pressing process comprises three hot rolling pressing processes, with the hot rolling pressure increasing successively and reaching 40 tons, 60 tons and 80 tons respectively, with a hot rolling temperature of 60 °C, and the electrode sheet being heated to 40 °C before the first entry into the hot rolling compaction.

[0252] The compression density here refers to the compression density of the battery cell when it is completely discharged, with the test method shown below.

[0253] The median C is 50 The graphitization degree of the positive electrode film layer is 1.005, with the porosity of the positive electrode film layer being 16.1%.

[0254] The positive electrode sheets are stripped and punched into specific shapes, the punched positive electrode sheets being classified by weight using a weighing sorting machine, in order to then be laminated using a lamination machine. (3) Production of the negative electrode sheet

[0255] The natural graphite, the conductive carbon black, the styrene-butadiene rubber (SBR) binder, and the sodium carboxymethylcellulose (CMC) thickener are mixed uniformly in a weight ratio of 95:1:2:2 and mixed with deionized water, whereby, after stirring and dispersion, the negative electrode paste is obtained, wherein the negative electrode paste is coated onto the copper foil, wherein, after drying, compacting, cutting, and foil forming, the negative electrode sheet is obtained.

[0256] The negative electrode sheets are stripped and punched into specific shapes, the punched negative electrode sheets being classified by weight using a weighing sorting machine, in order to then be laminated using a lamination machine. (4) Separator

[0257] Polyvinylidene fluoride (PVDF) is dissolved in N-methylpyrrolidone (NMP), stirred uniformly, and polyethylene glycol (PEG) is added as a pore-forming agent. The mixture is thoroughly stirred and mixed to obtain an adhesive layer solution. This adhesive layer solution is applied to the aforementioned base film with ceramic layers on both sides, pre-evaporated at 80 °C, dried at 110 °C, and then immersed in deionized water to dissolve the PEG, resulting in a separator with adhesive layers featuring porous structures on both sides. The base film thickness is 8 µm, the ceramic layer on one side is 3 µm thick, and the adhesive layer on one side is 1 µm thick. (5) Electrolyte

[0258] In a glove box with an argon atmosphere (H2O < 0.1 ppm, O2<0.1 ppm) the organic solvent consisting of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and ethylene carbonate (EC) is mixed uniformly.

[0259] Lithium hexafluorophosphate is then added and dissolved in the organic solvent to a concentration of 1.05 mol / L, followed by the addition of vinylene carbonate (VC) and stirring to obtain the electrolyte from embodiment 1.

[0260] In this case, based on the total mass of the electrolyte, the mass fraction of dimethyl carbonate is 26%, the mass fraction of ethyl methyl carbonate is 43.3%, the mass fraction of ethylene carbonate is 17.3% and the mass fraction of vinylene carbonate is 0.9%. (6) Battery production

[0261] A lamination machine is used to stack the positive electrode sheet, separator, and negative electrode sheet sequentially to create a laminated cell. The separator must be capable of insulating the positive and negative electrodes. The laminated cell is then glued to create a tight enclosure. After gluing, the laminated cell is placed into an outer packaging made of flexible aluminum-plastic foil. This foil consists of an inner layer of polypropylene, a middle layer of aluminum foil, and an outer layer of nylon. The outer packaging is die-cut from the aluminum-plastic foil and then formed and cut using a forming machine to achieve the desired shape and size.The aluminum-plastic foil is then heat-sealed to ensure that the sealing and packaging tension of the aluminum-plastic foil is ≥ 25 N / 8 mm. The battery is vacuum-baked, allowed to rest, filled with electrolyte, sealed, and packaged. The pouch battery is then hot-pressed and cold-pressed, with the temperature during hot-pressing being 45 °C for 2 minutes and the pressure being 90 kg / cm. 2 where the temperature during cold pressing is 25 °C, the time is 2 minutes and the pressure is 90 kg / cm². 2 After processes such as forming, vacuum extraction, and trimming, a battery cell is obtained. The battery cell has dimensions of 600 mm in length, 125 mm in width, and 20 mm in thickness.

[0262] The manufacturing processes of embodiments 2 to 5 are basically the same as in embodiment 1, except that the manufacturing processes of the positive electrode active material and the positive electrode sheet are adapted as follows: Example 2

[0263] (1) Preparation of the positive electrode active 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 ground to obtain a mixed raw material. The ratio of lithium dihydrogen phosphate to iron oxalate is 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 and the particle size D 90The particle size is 106.5 µm, where the mass fraction of the Fe element in the iron oxalate is 30.6% and the mass fraction of the trivalent iron element is 0.03%.

[0264] The mixed raw material is repeatedly ball-milled and demagnetized in a ball mill to obtain a mixed paste. The number and time of milling are controlled, with the particle size Dv being precisely determined. 50 The particle size of the mixed paste after grinding is 3.1 µm.

[0265] The mixed paste is spray-dried to obtain a dry precursor powder, the dry precursor powder having a light yellow appearance and a uniform color.

[0266] The precursor powder is placed in a sintering furnace, and the temperature is increased from 25 °C to 360 °C at a rate of 2 °C / min under a nitrogen atmosphere. This temperature is then maintained for 3.5 hours, after which it is increased at a rate of 5 °C / min to a second temperature of 775 °C and maintained for 10 hours. The temperature is then reduced and cooled. The mass fraction of the titanium element, based on the total mass of the positive electrode active material, is 1050 ppm, and the mass fraction of the volatile element is 950 ppm.

[0267] The material obtained is comminuted by an airflow pulverization process with a gradation frequency of 22 Hz and a pulverization pressure of 0.55 MPa to obtain a positive lithium iron phosphate electrode active material with carbon material on the surface.

[0268] The above-mentioned D10, D50, D90 and Dv50 refer to the data obtained using the Malvern laser diffraction method. (2) Production of the positive electrode sheet

[0269] The above-mentioned positive electrode active material with a mass fraction of 93.9%, the conductive agent with a mass fraction of 2%, and the polyvinylidene fluoride binder with a mass fraction of 3% are mixed in an N-methylpyrrolidone solvent, then the HNBR dispersing agent with a mass fraction of 1.1% is added, and the mixture is thoroughly mixed, stirred, and dispersed in a stirred tank to produce a positive electrode paste, with the positive electrode paste being transported to a coating process after completion of the stirring process;wherein the mass fractions of the positive electrode active material, the conductive agent, the binder and the dispersant are calculated based on the total mass of the solids in the positive electrode paste, wherein the conductive agent comprises a conductive carbon black with a mass fraction of 1.33% and a single-walled carbon nanotube with a mass fraction of 0.67%, wherein the specific surface area of ​​the conductive carbon black is 85 m²; 2 / g, the oil absorption value 200 ml / 100 g, the average length of the single-walled carbon nanotube 30 µm, the specific surface area 300 m² 2 / g and the mass fraction of metal impurities in the single-walled carbon nanotube is < 1%; wherein the positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, wherein after hot pressing a positive electrode sheet with a one-sided thickness of the positive electrode film layer of 105.89 µm and a compaction density of 2.36 g / cm³ 3 The stirring process comprises pre-stirring and main stirring, with the pre-stirring speed being lower than the main stirring speed, the pre-stirring speed being 25 rpm, the rotational speed being 500 rpm, and the pre-stirring time being 15 minutes.

[0270] The hot pressing process comprises three hot rolling pressing cycles, with the hot rolling pressure successively increasing to 35 tons, 55 tons, and 75 tons respectively, at a hot rolling temperature of 65°C. Prior to the first entry into the hot rolling compaction process, the electrode sheet is heated to 50°C. The compaction density refers here to the compaction density of the battery cell when fully discharged, as described below.

[0271] The positive electrode sheets are stripped and punched into specific shapes, the punched positive electrode sheets being classified by weight using a weighing sorting machine, in order to then be laminated using a lamination machine. Exemplary embodiment 3(1) Production of the positive electrode active material

[0272] Lithium carbonate, iron phosphate, sucrose, glucose, titanium dioxide and vanadium pentoxide are added to water and mixed in a premix tank at a speed of 1800 rpm, wherein the ratio of lithium carbonate and iron phosphate is such that the molar ratio of iron to phosphorus is 0.975, wherein the mass fraction of glucose relative to iron phosphate is 3.8% and the mass fraction of sucrose relative to iron phosphate is 1.9%; wherein the mixed raw material is ground twice in a sand mill, the first grinding being carried out using zirconium dioxide spheres with a diameter of 0.6 mm at a speed of 500 rpm and a grinding chamber pressure of less than 0.3 MPa for 1 hour, the second grinding then being carried out to obtain a mixed paste, wherein the particle size Dv 50 the mixed paste is 0.43 µm; the mixed paste is spray-dried to obtain a precursor powder, wherein the precursor powder is sintered to obtain a positive electrode material made of lithium iron phosphate, the sintering process comprising the following: First sintering: Sintering of the precursor powder in a nitrogen atmosphere with a temperature increase rate of 5 °C / min from 25 °C to 765 °C, holding the temperature for 10 hours and subsequent cooling to obtain a first sintered product;

[0273] Grinding and mixing: Addition of 0.5% sucrose, 1% glucose, and 3.0% polyethylene glycol to the total mass of the first sintered product to the first sintered product; dividing into two groups for grinding (third grinding process), whereby the grinding process is stopped when the 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 of ground products; the grinding process is stopped when the 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 of ground products; wherein the first group of ground products and the second group of ground products are mixed in a mass ratio of 72:28 to obtain a mixed intermediate product; wherein the mixed intermediate product is spray-dried; Second sintering: Sintering of the dried mixed intermediate product in a nitrogen atmosphere with a temperature increase rate of 5 °C / min from 25 °C to 800 °C, holding the temperature for 10 hours and subsequent cooling to obtain a second sintered product.

[0274] After sintering, the second sintered product is cooled to below 100 °C and pulverized by airflow pulverization to obtain a positive lithium iron phosphate electrode active material with carbon material on the surface. The airflow pulverization frequency is 25 Hz and the pulverization air pressure is 0.55 MPa. The mass fraction of the titanium element, based on the total mass of the positive electrode active material, is 1050 ppm, and the mass fraction of the volatile element is 950 ppm. (2) Production of the positive electrode sheet

[0275] The above-mentioned positive electrode active material with a mass fraction of 93.9%, the conductive agent with a mass fraction of 2%, and the polyvinylidene fluoride binder with a mass fraction of 3% are mixed in an N-methylpyrrolidone solvent, then the HNBR dispersing agent with a mass fraction of 1.1% is added, and the mixture is thoroughly mixed, stirred, and dispersed in a stirred tank to produce a positive electrode paste, with the positive electrode paste being transported to a coating process after completion of the stirring process;wherein the mass fractions of the positive electrode active material, the conductive agent, the binder and the dispersant are calculated based on the total mass of the solids in the positive electrode paste, wherein the conductive agent comprises a conductive carbon black with a mass fraction of 1.33% and a single-walled carbon nanotube with a mass fraction of 0.67%, wherein the specific surface area of ​​the conductive carbon black is 85 m²; 2 / g, the oil absorption value 200 ml / 100 g, the average length of the single-walled carbon nanotube 30 µm, the specific surface area 300 m² 2 / g and the mass fraction of metal impurities in the single-walled carbon nanotube is < 1%; wherein the positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, wherein after hot pressing a positive electrode sheet with a one-sided thickness of the positive electrode film layer of 106.21 µm and a compaction density of 2.37g / cm³ 3 The drying temperature is 95 °C and the speed is 2.0 m / min.

[0276] The hot pressing process comprises three hot rolling pressing cycles, with the hot rolling pressure successively increasing to 35 tons, 55 tons, and 75 tons respectively, at a hot rolling temperature of 65°C. Prior to the first entry into the hot rolling compaction process, the electrode sheet is heated to 50°C. The compaction density refers here to the compaction density of the battery cell when fully discharged, as described below.

[0277] The positive electrode sheets are stripped and punched into specific shapes, the punched positive electrode sheets being classified by weight using a weighing sorting machine, in order to then be laminated using a lamination machine. Example 4

[0278] The manufacturing process of embodiment 4 is basically the same as in embodiment 1, except that the manufacturing process of the positive electrode active material and the hot pressing process of the positive electrode sheet differ slightly, the specific differences including the following: (1) The carbon sources in the mixed raw material are sucrose and glucose, the mass of which is 2 wt% compared to the mass of the iron phosphate and the mass of which is 4 wt% compared to the mass of the iron phosphate; (2) The temperature rise and sintering process differs. The precursor powder is sintered at least twice in a nitrogen atmosphere, with the first sintering temperature being 765 °C and the holding time being 8 hours, in order to obtain a primary sintered product.

[0279] To the primary sintered product, 1.5 wt% (based on the mass of the primary sintered product) of glucose, 3.0 wt% (based on the mass of the primary sintered product) of polyethylene glycol, titanium dioxide, and vanadium pentoxide are added. After uniform grinding, the product is divided into two groups for secondary grinding. The grinding parameters of the two groups are different, and the Dv 50 The particle size is controlled to 2.2 µm after the first group has been milled, while the Dv 50The particle size after milling the second group is controlled to 0.4 µm. The milled particles of the first and second groups are mixed in a mass ratio of 30:70, spray-dried, and sintered a second time. The second sintering temperature is 815 °C and the holding time is 10 hours.

[0280] The mass fraction of the Ti element is 1050 ppm relative to the total mass of the positive electrode active material, and the mass fraction of the V element is 950 ppm.

[0281] (3) wherein the positive electrode paste is transferred and coated onto an aluminium foil of the positive electrode current collector and dried, wherein after hot pressing a positive electrode sheet with a one-sided thickness of the positive electrode film layer of 106.34 µm and a compaction density of 2.37g / cm³ 3 The drying temperature is 95 °C and the speed is 2.0 m / min.

[0282] The hot pressing process comprises three hot rolling pressing cycles, with the hot rolling pressure successively increasing to 35 tons, 55 tons, and 70 tons respectively, at a hot rolling temperature of 65°C. Prior to the first entry into the hot rolling compaction process, the electrode sheet is heated to 50°C. The compaction density refers here to the compaction density of the battery cell when fully discharged, as described below. Example 5

[0283] The manufacturing process of embodiment 5 is basically the same as in embodiment 1, except that the sintering process of the positive electrode active material and the hot pressing process of the positive electrode sheet differ slightly, in detail: . (1) The precursor powder is sintered in a nitrogen atmosphere in two temperature rise stages to obtain the positive electrode active material: The temperature is increased from 25°C to 440°C at a temperature rise rate of 2°C / min (first temperature rise stage) and the temperature is held for 2.5 hours, the temperature is increased from 440°C to 760°C at a temperature rise rate of 5°C / min (second temperature rise stage) and the temperature is held for 11 hours, with the strength of the airflow pulverization being further enhanced to obtain a positive lithium iron phosphate electrode active material with carbon material on the surface. (2) The positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby after hot pressing a positive electrode sheet with a one-sided thickness of the positive electrode film layer of 105.65 µm and a compaction density of 2.36 g / cm³ 3 The transfer and coating speed is 20 m / min.

[0284] The hot pressing process comprises three hot rolling pressing processes, with the hot rolling pressure increasing successively and reaching 45 tons, 60 tons and 80 tons respectively, with a hot rolling temperature of 60 °C, and the electrode sheet being heated to 40 °C before the first entry into the hot rolling compaction.

[0285] The manufacturing processes of embodiments 6 to 10 are basically the same as in embodiment 1, except that the manufacturing process of the positive electrode sheet is adapted as follows: Example 6

[0286] In embodiment 1, the positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried. By adjusting the pressure, calender speed, roller gap, holding time, number of calenders, and by controlling the coating density in the hot pressing process, a positive electrode sheet with a one-sided thickness of 91.88 µm is obtained by hot pressing, with the compaction density of the positive electrode sheet being 2.36 g / cm³. 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer. Example 7

[0287] In embodiment 1, the positive electrode paste is transferred and coated onto an aluminum foil of the positive electrode current collector and dried. By adjusting the pressure, calender speed, roller gap, holding time, number of calenders, and by controlling the coating density in the hot pressing process, a positive electrode sheet with a one-sided thickness of 116.09 µm is obtained by hot pressing, with the compaction density of the positive electrode sheet being 2.36 g / cm³. 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer. Example 8

[0288] The positive electrode paste of embodiment 1 is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby a positive electrode sheet with a one-sided thickness of 72.34 µm is obtained by hot pressing by adjusting the pressure, the calender speed, the roller gap, the holding time, the number of calenders and by controlling the coating density in the hot pressing process, wherein the compaction density of the positive electrode sheet is 2.36 g / cm³ 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer. Example 9

[0289] The positive electrode paste of embodiment 1 is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby a positive electrode sheet with a one-sided thickness of 83.91 µm is obtained by hot pressing by adjusting the pressure, the calender speed, the roller gap, the holding time, the number of calenders and by controlling the coating density in the hot pressing process, wherein the compaction density of the positive electrode sheet is 2.36 g / cm³ 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer. Example 10

[0290] The positive electrode paste of embodiment 1 is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby a positive electrode sheet with a one-sided thickness of 98.93 µm is obtained by hot pressing by adjusting the pressure, the calender speed, the roller gap, the holding time, the number of calenders and by controlling the coating density in the hot pressing process, wherein the compaction density of the positive electrode sheet is 2.52 g / cm³ 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer.

[0291] The manufacturing process of embodiment 11 is basically the same as in embodiment 1, except that no dispersant is added during the manufacturing process of the positive electrode sheet, in detail: The aforementioned positive electrode active material with a mass fraction of 94.9%, the conductive agent with a mass fraction of 2.05%, and the polyvinylidene fluoride binder with a mass fraction of 3.05% are mixed in an N-methylpyrrolidone solvent and thoroughly blended, stirred, and dispersed in a stirred tank to produce a positive electrode paste. After completion of the stirring process, the positive electrode paste is transported to a coating process. The mass fractions of the positive electrode active material, the conductive agent, and the binder are calculated based on the total mass of solids in the positive electrode paste.

[0292] The manufacturing process of comparative example 1 is basically the same as in embodiment 1, except that the sintering process of the positive electrode active material differs slightly, in detail: Comparative example 1

[0293] The precursor powder is sintered in a nitrogen atmosphere in two temperature rise stages to obtain the positive electrode active material: The temperature is increased from 25°C to 500°C at a temperature rise rate of 2°C / min (first temperature rise stage) and the temperature is held for 3.5 hours, while the temperature is increased from 500°C to 800°C at a temperature rise rate of 5°C / min (second temperature rise stage) and the temperature is held for 13 hours, during which the strength of the airflow pulverization is again reduced to obtain a positive lithium iron phosphate electrode active material with carbon material on the surface.

[0294] The manufacturing process of comparative example 2 is basically the same as in embodiment 1, except that the manufacturing process of the positive electrode sheet is adapted as follows: Comparative example 2

[0295] The positive electrode paste of embodiment 1 is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby a positive electrode sheet with a one-sided thickness of 65.08 µm is obtained by hot pressing by adjusting the pressure, the calender speed, the roller gap, the holding time, the number of calenders and by controlling the coating density in the hot pressing process, wherein the compaction density of the positive electrode sheet is 2.36 g / cm³ 3 The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer.

[0296] The manufacturing process of comparative example 3 is basically the same as in comparative example 1, except that the manufacturing process of the positive electrode sheet is adapted as follows: The positive electrode paste of comparative example 1 is transferred and coated onto an aluminum foil of the positive electrode current collector and dried, whereby a positive electrode sheet with a one-sided thickness of 91.9 µm is obtained by hot pressing by adjusting the pressure, calender speed, roller gap, holding time, number of calenders and by controlling the coating density in the hot pressing process, wherein the compaction density of the positive electrode sheet is 2.36 g / cm³ 3The compression density refers here to the compression density of the battery cell when it is completely discharged, with the test method shown below. The number of laminate layers remains unchanged, and the thickness of the battery cell is adjusted according to the thickness of the positive electrode film layer. Test procedure: 1. Battery cell capacity

[0297] Charging at 25 °C with a charging rate of 0.5 C of the nominal capacity of the battery cell to 3.65 V, then charging with a constant voltage of 3.65 V to 0.05 C, resting for 10 minutes and subsequently discharging with a discharge rate of 1 C to 2.5 V and resting for 10 minutes, whereby the capacity C during the discharge process is calculated in Ah using the formula C=I*t. 2. Aluminum leakage ratio after cutting the electrode sheet

[0298] The proportion of positive electrode sheets with aluminum leakage can be determined using known methods, for example the following method can be used: a certain number of striped and punched electrode sheets are observed by CCD and the frequency K1 of the electrode sheets with aluminum leakage is counted, whereby the proportion of electrode sheets with aluminum leakage is calculated as K1 / total number of electrode sheets × 100 %; where the total number of electrode sheets is 100. 3. Number of cycles until capacity drops to 90%

[0299] Charging at 25 °C with a charging rate of 0.5 C of the nominal capacity of the battery cell to 3.65 V, then charging with a constant voltage of 3.65 V to 0.05 C, resting for 10 minutes and subsequently discharging with a discharge rate of 1 C to 2.5 V and resting for 10 minutes, wherein the above-described charge and discharge cycle is considered one cycle, wherein the test is terminated when the battery capacity drops to 90% of the nominal capacity, with the number of cycles being recorded as the number of cycles at 90% SOH. Test result Table 1 Positive electrode sheet Battery cell capacity Ah Aluminum leakage ratio after cutting the electrode blade First area One-sided thickness of the positive electrode film layer µm Compression density of the positive electrode sheet in a completely discharged battery cell g / cm³ 3 Area ratio of the first particle with particle size R1, which satisfies R1≥ 1000 nm MedianL R1A150 the sphericity of the first particle with a particle size R1 that satisfies R1 ≥1000 nm Example 1 36,64 % 0,687 105,64 2,36 160 0% Example 2 34,78 % 0,673 105,89 2,36 162 0% Example 3 34,95 % 0,745 106,21 2,37 162 0% Example 4 49,96 % 0,72 106,34 2,37 161 1 % Example 5 12,02 % 0,75 105,65 2,36 159 0% Example 6 38,09 % 0,67 91,88 2,36 140 0% Example 7 38,44 % 0,653 116,09 2,36 177 0% Example 8 36,29 % 0,69 72,34 2,36 110 0 % Example 9 36,37 % 0,688 83,91 2,36 128 0% Example 10 36,88 % 0,685 98,93 2,52 159 0 % Comparative example 1 55,91 % 0,631 105,44 2,36 159 3% Comparative example 2 36,58 % 0,688 65,08 2,36 100 0% Comparative example 3 55,82 % 0,632 91,90 2,36 139 2%

[0300] From the comparison of the embodiments and the comparative examples, it can be seen that the one-sided thickness H of the positive electrode film layer is 70 µm to 120 µm, wherein, with respect to the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first region, the area of ​​the first particle with a particle size R1, which satisfies R1 ≥ 1000 nm, is 12% to 50%, wherein in the cumulative distribution curve of the sphericity area of ​​the first particles in the cross-section along the thickness direction of the electrode sheet in the first region, the median of the sphericity L R1A1 50 0.6-0.8, where the battery cell is in a fully discharged state and the compression density of the positive electrode sheet is 2.3 g / cm³ 3 up to 2.6 g / cm³ 3This ensures that the battery cell maintains good capacity while improving the voltage concentration between the positive electrode film layer and the current collector, thereby mitigating the phenomenon of the film layer detaching or even falling off during the stamping process of the laminated cell, thus reducing safety risks.

[0301] From a comparison of embodiment 4 and embodiments 1 to 3 and embodiment 5, it can be seen that, with respect to the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is 12% to 40%, which is advantageous for the battery because it further improves the voltage concentration between the positive electrode film layer and the current collector and at the same time maintains a high capacity, thus mitigating the phenomenon of the film layer of the laminated cell coming loose or even falling off during the stamping process and reducing safety risks.

[0302] From the comparison of embodiments 8 and 9 and embodiments 6 and 7, it can be seen that the one-sided thickness H of the positive electrode film layer is 90 µm to 120 µm, which is advantageous for a further improvement of the battery capacity. Table 2 Positive electrode sheet Number / circles of cycles until capacity drops to 90% First area One-sided thickness of the positive electrode film layer µm Compression density of the positive electrode sheet in a fully discharged battery cell (g / cm²) 3 Area ratio of the first particle with particle size R1, which satisfies R1 ≥1000 nm MedianL R1A150 the sphericity of the first particle with a particle size R1 that satisfies R1 ≥1000 nm Example 1 36,64 % 0,687 105,64 2,36 1009 Example 2 34,78 % 0,673 105,89 2,36 1064 Example 3 34,95 % 0,745 106,21 2,37 1097 Example 4 49,96 % 0,72 106,34 2,37 967 Example 5 12,02 % 0,75 105,65 2,36 1059 Example 6 38,09 % 0,67 91,88 2,36 957 Example 7 38,44 % 0,653 116,09 2,36 939 Example 8 36,29 % 0,69 72,34 2,36 1067 Example 9 36,37 % 0,688 83,91 2,36 1045 Example 10 36,88 % 0,685 98,93 2,52 990

[0303] From a comparison of embodiment 7 and embodiments 1 to 6 and 8 to 10, it can be seen that the median of the sphericity L R1A2 50 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in cross-section along the thickness direction of the electrode sheet in the first area 1 µm ≤ R1 ≤ 5 µm fulfills 0.67 to 0.75, which is advantageous to alleviate the phenomenon of the film layer of the laminated cell coming loose or even falling off during the stamping process, to reduce the voltage concentration caused by large particles and to improve the cycle performance of the battery. Table 3 Type and mass fraction of the dispersing agent Proportion of the total area of ​​the agglomeration of the conductive medium Aluminum leakage ratio after cutting electrode blade Battery cell capacity Ah Number / circles of cycles until capacity drops to 90% Example 1 1.1% hydrogenated nitrile rubber HNBR 1,99 % 0% 160 1009 Example 11 No dispersant added 5,82 % 0% 160 908

[0304] From the comparison of embodiment 1 and embodiment 11, it can be seen that the area ratio of an agglomeration region of the conductive medium, based on the total area of ​​the cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, is 1.5% to 5%, which serves to reduce the problem of local polarization and even lithium plating that occurs during the battery's cycle process, and to increase the battery's lifespan.

[0305] It should be noted that the present application is not limited to the embodiments mentioned above. The above embodiments are merely examples, and all embodiments that have essentially the same structure and effect as the technical idea within the technical solution of the present application are all included within the technical scope of the present application. Furthermore, other possibilities in which various modifications conceivable to a person skilled in the art are added to the embodiments, and some components of the embodiments are combined to form other embodiments, are also included within the scope of the present application without departing from the core of the present application. 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

[0152]

Claims

[1] Battery cell, characterized by , that it comprises a laminated cell, wherein the laminated cell comprises a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises lithium-containing transition metal phosphate particles, wherein a carbon material is provided on at least one part of the surface of the lithium-containing transition metal phosphate particles; wherein the one-sided thickness of the positive electrode film layer is denoted by H and H is 70 µm to 120 µm, wherein the positive electrode film layer has a first region, the first region being located at the bottom of the positive electrode film layer near the positive electrode current collector, wherein, based on the total area of ​​the particles in cross-section along the thickness direction of the electrode sheet in the first region, the area ratio of the first particle with a particle size R1 satisfying R1 ≥ 1000 nm is 12% to 50%; where a median of sphericity L R1A1 50 in a cumulative distribution curve of a sphericity surface of the first particle, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region R1 ≥ 1000 nm is 0.6 to 0.8; where the density of the positive electrode sheet is 2.3 g / cm³ 3 up to 2.6 g / cm³ 3is the value when the battery cell is in a completely discharged state. [2] Battery cell according to claim 1, characterized by , that the one-sided thickness of the positive electrode film layer is designated by H and H is 90 µm to 120 µm. [3] Battery cell according to claim 1 or 2, characterized by , that the one-sided thickness of the positive electrode film layer is designated by H and H is 100 µm to 120 µm. [4] Battery cell according to any one of claims 1 to 3, characterized by , that the positive electrode film layer further comprises a conductive agent, wherein the total area of ​​an agglomeration region of the conductive agent, relative to the total area of ​​the cross-sectional area of ​​the positive electrode film layer along the thickness direction of the electrode sheet, is 0.2% to 6%, optionally 1.5% to 5%. [5] Battery cell according to claim 4, characterized by, that the conductive agent comprises a carbon nanotube, wherein the carbon nanotube comprises one or more of the following types: a single-walled carbon nanotube, a thin-walled carbon nanotube and a multi-walled carbon nanotube, optionally the conductive agent further comprises a conductive carbon black. [6] Battery cell according to claim 4 or 5, characterized by , that the agglomeration area of ​​the conductive medium includes the carbon nanotube and the conductive soot. [7] Battery cell according to claim 6, characterized by , that the mass fraction C1 of the carbon nanotube, relative to the mass of the positive electrode film layer, satisfies the following: 0 < C1 ≤ 2.5% and the mass fraction C2 of the conductive carbon black satisfies the following: 0 < C1 ≤ 2.5%. [8] Battery cell according to any one of claims 1 to 7, characterized by, that the positive electrode film layer further comprises a dispersant, wherein the dispersant comprises a hydrogenated nitrile rubber HNBR. [9] Battery cell according to claim 8, characterized by , that the mass fraction of the dispersing agent relative to the mass of the positive electrode film layer is 0.5% to 2%. [10] Battery cell according to any one of claims 1 to 9, characterized by , that the lithium-containing transition metal phosphate particles in the positive electrode film layer comprise components that are represented by the following general formula: Li m Fe x P y O j Q q Formula 1 Where Q includes one or more of the following elements: Al, Na, K, Mg, Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, V, Ti, B, S, Si, N, F, C1 and Br, 0.8 ≤ m ≤ 1.15, 0.9 ≤ x ≤ 1, 0.95 ≤ y ≤ 1, 3.5 ≤ j ≤ 4 and 0 ≤ q ≤ 0.

1. [11] Battery cell according to any one of claims 1 to 10, characterized by , that the lithium-containing transition metal phosphate particles comprise the element titanium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the titanium mass fraction is 500 ppm to 8000 ppm, optionally 1000 ppm to 3000 ppm. [12] Battery cell according to any one of claims 1 to 11, characterized by , that the lithium-containing transition metal phosphate particles comprise the element vanadium, wherein, based on the total mass of the lithium-containing transition metal phosphate particles in the positive electrode film layer, the vanadium mass fraction is 500 ppm to 5000 ppm, optionally 500 ppm to 3000 ppm. [13] Battery cell according to any one of claims 1 to 12, characterized by, that the battery cell further comprises a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the separator comprises a base film and a ceramic layer arranged on both sides of the base film, as well as an adhesive layer arranged on at least one side of the ceramic layer facing away from the base film side, wherein the adhesive layer is a continuous layer having a porous structure and the adhesive layer comprises a vinylidene fluoride polymer. [14] Battery cell according to any one of claims 1 to 13, characterized by that the battery cell comprises an electrolyte, wherein the electrolyte meets at least one of the following conditions: (1) the electrolyte comprises a solvent comprising ethyl methyl carbonate (EMC) and / or ethylene carbonate (EC) and dimethyl carbonate (DMC); (2) the mass fraction of dimethyl carbonate is 18% to 32% based on the total mass of the electrolyte; (3) the total mass fraction of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) is 52% to 71% based on the total mass of the electrolyte; (4) The electrolyte comprises an electrolyte salt, wherein the electrolyte salt comprises lithium hexafluorophosphate (LiPF6), wherein the concentration of lithium hexafluorophosphate in the electrolyte is 0.9 mol / L to 1.2 mol / L. [15] Battery cell according to any one of claims 1 to 14, characterized by , that, with respect to the total area of ​​the particles in the cross-section along the thickness direction of the electrode sheet in the first area, the area ratio of the particles with a particle size R1 that meets 1 µm ≤ R1 ≤ 5 µm is 12% to 40%. [16] Battery cell according to any one of claims 1 to 15, characterized by , that the median of the sphericity L R1A250 in the cumulative distribution curve of the sphericity area, in which the particle size R1 in the cross-section along the thickness direction of the electrode sheet in the first region 1 µm ≤ R1 ≤ 5 µm is 0.65 to 0.75, optionally 0.67 to 0.

75. [17] Battery cell according to any one of claims 1 to 16, characterized by , that in the cumulative distribution curve of the degree of graphitization, i.e., the C-value of the positive electrode film layer, which is obtained by the laser microconfocal Raman spectrometer in surface scanning mode, the median C 50 the degree of graphitization is greater than or equal to 0.95 and less than or equal to 1.20, where the degree of graphitization, i.e. the C value I G / I D is, where I G a G-peak intensity of the Raman spectrum at 1580 ± 100 cm⁻¹ -1 represents and Into the D peak intensity of the Raman spectrum at 1350 ± 100 cm -1 represents. [18] Battery cell according to any one of claims 1 to 17, characterized by that the porosity of the positive electrode film layer is between 14% and 28%. [19] Battery cell according to any one of claims 1 to 18, characterized by , that the positive electrode film layer in the lower region near the positive electrode current collector is provided with a primer layer, wherein the primer layer meets at least one of the following conditions: (1) the primer layer comprises a conductive agent and a binder, wherein the conductive agent comprises a carbon nanotube and a conductive carbon black and the binder comprises a vinylidene fluoride polymer; (2) the primer layer has a thickness of 0.5 µm to 5 µm. [20] Battery cell according to any one of claims 1 to 19, characterized by, that the battery cell comprises a housing body, wherein the laminated cell is contained in the housing body, wherein the size of the housing body in the longitudinal direction is L0, wherein the size of the housing body in the width direction is W0 and the size of the housing body in the thickness direction is H0, 450 mm ≤ L0 ≤ 1300 mm, 100 mm ≤ W0 ≤ 150 mm and 14 mm ≤ H0 ≤ 22 mm. [21] Battery cell according to claim 20, characterized by , that the length L0 of the housing body in the longitudinal direction satisfies the following: 450 mm ≤ L0 ≤ 650 mm. [22] Battery cell according to claim 20, characterized by , that the length L0 of the housing body in the longitudinal direction satisfies the following: 900 mm ≤ L0 ≤ 1300 mm. [23] Battery cell according to one of claims 20 to 22, characterized by that the housing body meets at least one of the following conditions: (1) The material of the housing body is a soft packaging material, the soft packaging material comprising an aluminium-plastic composite film, optionally a composite film consisting of one or more of the following materials formed with aluminium: polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), nylon, polyethylene terephthalate (PET), polyethylene (PE); (2) the housing body comprises a first sealing area, wherein the first sealing area is arranged at at least one end of the laminated cell extending along the width direction, wherein the first sealing area comprises a fold-edge structure extending along the length direction, wherein the fold-edge structure is provided with packaging adhesive, and wherein the packaging adhesive is arranged continuously along the length direction and fixes the fold-edge structure; (3) The housing body has at least one second sealing area, wherein the second sealing area is located at at least one end of the laminated cell extending along the longitudinal direction of the housing body, and wherein the second sealing area is located on the electrode tab side of the laminated cell. [24] Battery cell according to any one of claims 1 to 23, characterized by , that several rubber rings are provided on the outer circumference of the laminated cell, surrounding it in the width direction, wherein the rubber rings surrounding it in the width direction are arranged at intervals along the length direction. [25] Battery cell according to any one of claims 1 to 24, characterized by , that the capacity of the battery cell at 25 °C is 100 Ah to 300 Ah, optionally 110 Ah to 190 Ah, and further optionally 125 Ah to 180 Ah. [26] Battery device, characterized bythat it comprises the battery cell according to any one of claims 1 to 25. [27] Power-consuming device, characterized by , that the power-consuming device comprises the battery device according to claim 26, wherein the battery cell is used to provide electrical energy. [28] Energy storage device, characterized by that the energy storage device comprises the battery device according to claim 26, wherein the battery cell is used to store electrical energy.

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