Battery cell, battery device and power-consuming device

Abstract

Battery cell comprising a cathode foil, an anode foil and an electrolyte, characterized in that the cathode foil comprises a cathode collector and a cathode film layer arranged on the surface of at least one side of the cathode collector, wherein the cathode film layer comprises an active cathode material, wherein the active cathode material comprises lithium-containing transition metal phosphate particles, wherein (D V90 -D V10 ) / D V50 the number of particles in the cathode film layer is 4 to 8; where the one-sided areal density of the cathode film layer is 200 mg / 1540.25 mm² 2 up to 450 mg / 1540.25 mm 2 amounts; where, with reference to the total area of ​​the cathode film layer, the area fraction of the particles with a roundness of greater than or equal to 0.75 in the cathode film layer is 60% to 80%.

Description

TECHNICAL AREA

[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. STATE OF THE ART

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

[0003] The active cathode material is a crucial component of battery cells, and lithium-containing transition metal phosphate materials possess significant development potential due to their stable structure, good safety, and long cycle life. However, given the market demands for battery cell energy density and the kinetics of lithium-containing transition metal phosphate systems, it is challenging for existing technology to simultaneously improve upon these performance characteristics, making it a pressing technical problem in this field. CONTENT OF THE PRESENT INVENTION

[0004] In view of the problems mentioned above, the present application provides a battery cell, a battery device and a power-consuming device, each of which is described below.

[0005] A first aspect of the present application provides a battery cell comprising a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on the surface of at least one side of the cathode collector, and wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises lithium-containing transition metal phosphate particles, wherein (D V90 -D V10 ) / D V50 the number of particles in the cathode film layer is 4 to 8; wherein, based on the total mass of the cathode film layer, the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 60% to 80%.

[0006] In the present application, the control of the relationship (D) V90 -D V10 ) / D V50The particle size distribution of 4 to 8 contributes to establishing a rational particle size distribution. This allows smaller particles to fill the voids between larger particles, forming a more compact packing structure that reduces porosity. This increases the packing density of the electrode foil and thus improves the energy density of the battery. However, the significant proportion of larger particles increases the tortuosity within the cathode film layer and lengthens the lithium-ion transport pathways. This leads to local polarization, increases the battery impedance, and impairs the battery kinetics. The present application further addresses this problem by improving the roundness of the particles within the cathode film layer. If the mass fraction of particles with a roundness greater than or equal to 0.75 within the cathode film layer falls within the aforementioned range, this facilitates the formation of regular and continuous pore channels.This reduces the degree of curvature and branching within the pore channels, thereby improving lithium-ion transport efficiency and achieving a balance between the kinetics and cycle life of the battery cell.

[0007] In each embodiment, the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 65% to 75%, relative to the total mass of the cathode film layer. Due to their regular shape, particles with high roundness can be packed more densely after rolling. However, an excessively high proportion can increase particle slippage, thereby impairing the stability of the cathode film layer and reducing the compaction density. Therefore, maintaining the mass fraction of particles with a roundness greater than or equal to 0.75 within the aforementioned range facilitates a balance between high compaction density and low tortuosity within the cathode film layer.

[0008] In each embodiment, the mass fraction of particles with a roundness of less than or equal to 0.4 in the cathode film layer is 5% to 20%, optionally 10% to 15%, relative to the total mass of the cathode film layer. During packing, particles with high roundness can exhibit significant gaps between them, limiting further increases in packing density. Consequently, a mixed strategy is employed, utilizing both low- and high-roundness particles. This approach facilitates the interlocking of particles with different shapes and sizes, thereby reducing porosity and forming a more compact packing structure, thus increasing packing density.

[0009] In each embodiment, (D V90 -D V10 ) / D V50 of the particles in the cathode film layer 5 to 7. By maintaining this ratio (D V90 -DV10 ) / D V50 Within the aforementioned area, both a high energy density and a low tortuosity of the cathode film layer are achieved, further optimizing polarization and lifespan during the battery cycle.

[0010] In each embodiment, the one-sided areal density of the cathode film layer is 200 mg / 1540.25 mm². 2 up to 450 mg / 1540.25 mm 2 The areal density of the cathode film layer has a significant influence on lithium-ion transport rates. Too low an areal density can impair energy density, while too high an areal density can increase ion transport paths and thus reduce transport rates. Maintaining the areal density of the cathode film layer within the aforementioned range improves both the energy density and the kinetic performance of the battery.

[0011] In each embodiment, D is V50 The particle size in the cathode film layer is 0.5 µm to 0.9 µm, optionally 0.6 µm to 0.8 µm. The size of the D V50 The particle size distribution in the cathode film layer influences both the packing density and the tortuosity of the cathode film layer. An excessively high density (D) V50 A higher D-value increases the porosity between the particles, making it difficult to increase the packing density of the cathode film layer. Conversely, a D-value that is too low leads to... V50 -value to fragmented and interrupted ion conduction pathways between particles, thereby reducing ion transport efficiency and simultaneously hindering electrolyte permeation and blocking ion transport pathways. By maintaining the D V50 By increasing the particle energy density within the cathode film layer within the aforementioned range, the energy density and cycle lifetime of the single cell are further improved.

[0012] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the first peak of this bimodal distribution being located at 0.45 µm to 0.75 µm.

[0013] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the first peak of this bimodal distribution being located at 0.6 µm to 0.7 µm.

[0014] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the second peak of this bimodal distribution located at 0.6 µm to 0.97 µm.

[0015] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the second peak of this bimodal distribution located at 0.7 µm to 0.91 µm.

[0016] The bimodal particle size distribution curve in the cathode film layer indicates the presence of both large and small particles of varying dimensions within the cathode film layer. The position of the first peak and / or the second peak within the aforementioned range facilitates the filling of voids between large particles by small particles, thereby increasing the electrode film's packing density and further improving the battery's energy density.

[0017] In each embodiment, the cathode film layer comprises a conductive element, wherein the mass fraction of the conductive element is 0.5% to 1% of the total mass of the cathode film layer. Relative to the total mass of the cathode film layer, the mass fraction of the one-dimensional conductive element lies within the aforementioned range, such that the cathode film layer exhibits excellent electronic conductivity while simultaneously maintaining a high loading of the active material. This achieves a balance between kinetic power and energy density.

[0018] In each embodiment, the conductive medium comprises a one-dimensional conductive material, which is optionally one or more single-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanofibers. The one-dimensional conductive material has a fibrous structure with lengths in the micrometer range, enabling the formation of a continuous linear conductive network within the electrode. This allows for an effective conductive network at lower loading levels, thereby reducing the required amount of conductive material and further improving the battery's energy density.

[0019] In each embodiment, the conductive medium comprises a zero-dimensional conductive medium, which is optionally one or more of conductive carbon black, Ketjen carbon black, and hard carbon. The zero-dimensional conductive medium forms a conductive network through point contacts between active materials. Since it typically has a high specific surface area, it effectively fills voids between active materials, further improving the electrode conductivity and increasing the overall kinetic performance of the battery.

[0020] In each embodiment, the porosity of the cathode film layer is 15% to 25%, optionally 18.2% to 22.9%. By controlling the porosity of the cathode film layer within the aforementioned range, the active cathode material can achieve a high compression density and energy density after roller compaction. A specific porosity facilitates electrolyte wetting of the active cathode material, thereby further optimizing ion transport efficiency, reducing polarization, and extending the battery's cycle life.

[0021] In each embodiment, the lithium-containing transition metal phosphate comprises a component represented by the following general formula: Li x A y Me a M b P 1-c X c Y z , where 0.1 ≤ x ≤ 1.3, 0 ≤ y ≤ 1.3 and 0.9 ≤ x + y ≤ 1.3; 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5 and 0.9 ≤ a + b ≤ 1.5; 0 ≤ c ≤ 0.5; and 3 ≤ z ≤ 5; where A includes one or more of Na, K, Mg; Me includes one or more of Mn, Fe, Co, Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; X includes one or more of S, Si, Cl, B, C, N; Y includes one or more of O, F.

[0022] The lithium-containing transition metal phosphate materials mentioned above exhibit good thermal stability and cycle stability, thereby contributing to improved battery safety and cycle performance.

[0023] In each embodiment, the tortuosity of the cathode film layer ranges from 2.3 to 2.7. A cathode film layer tortuosity within the aforementioned range indicates straighter lithium ion transport pathways within the cathode film layer. This results in shorter diffusion paths for lithium ions within the electrolyte, reduced diffusion resistance, decreased accumulation and concentration gradients of lithium ions within the electrode, and a reduction in the polarization effect. Consequently, superior kinetic performance is achieved, thereby extending the battery's cycle life.

[0024] In each embodiment, the density of the cathode film layer in the fully discharged state is 2.40 g / cm³. 3 up to 2.65 g / cm³ 3 The pressure density of the cathode film layer is within the above range, which is beneficial for improving the energy density of the battery cell.

[0025] A second aspect of the present application provides a battery device comprising a battery cell according to the first aspect of the present application.

[0026] A third aspect of the present application provides a power-consuming device comprising at least one of the battery cell according to the first aspect of the present application and the battery device according to the third aspect of the present application.

[0027] The above explanation represents only a general outline of the technical solution of the present application. In conjunction with the content of the description, the present invention can be implemented so that the technical measures of the present application can be understood more clearly. The specific embodiments of the present application are explained in more detail below so that the above and other objectives, features, and advantages of the present application become more apparent and can be easily understood. BRIEF DESCRIPTION OF THE DRAWING

[0028] In the accompanying drawings, unless otherwise indicated, the same reference numerals denote identical or similar components or elements in several drawings. These drawings are not necessarily to scale. It is understood that these drawings merely depict certain embodiments disclosed herein and should not be construed as limiting the scope of this application. Fig. Figure 1 shows a cross-sectional polishing electron microscope morphology diagram of the cathode film layer in an embodiment of the present application; Fig. Figure 2 shows a schematic diagram of a battery cell in an embodiment of the present application; Fig. Figure 3 shows an exploded view of a battery cell in an embodiment of the present application according to Fig. 2; Fig.Figure 4 shows a schematic diagram of a battery module in an embodiment of the present application; Fig. Figure 5 shows a schematic diagram of a battery pack in an embodiment of the present application; Fig. Figure 6 shows an exploded view of a battery pack in an embodiment of the present application according to Fig. 5; Fig. Figure 7 shows a schematic diagram of a power-consuming device in an embodiment of the present application which uses a secondary battery as a power source. Reference symbol list 1 battery pack 2 Upper Case 3 Lower Case 4 battery modules 5 battery cells 51 Housing body 52 Electrode assembly 53 Cover assembly DETAILED DESCRIPTION

[0029] The following section describes in detail embodiments of the battery cell, battery device, and power-consuming device of the present application with reference to the accompanying drawings. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure will be left out. This is to prevent the following description from becoming unnecessarily long and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description serve to ensure the complete understanding of the present application by those skilled in the art and are not intended to limit the subject matter specified in the claims.

[0030] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60-120 and 80-110 is specified for a particular parameter, a range of 60-110 and 80-120 is also to be expected. Furthermore, if the minimum values ​​1 and 2 and the maximum values ​​3, 4, and 5 are specified, the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0031] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined to form new technical solutions, and such a technical solution should be considered to be covered by the disclosure of the present application.

[0032] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined to form a new technical solution, and such a technical solution should be considered to be covered by the disclosure of the present application.

[0033] Unless expressly stated otherwise, all steps of the present application may be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the method may also include step (c) means, for example, that step (c) may be added to the method in any order; e.g., the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b).

[0034] In the present application, the terms "plural" and "multiple" refer to two or more.

[0035] Unless otherwise stated, the terms used in this application have the known meanings as generally understood by those skilled in the art.

[0036] Unless otherwise specified, the values ​​of the parameters mentioned in this application can be determined by various test methods commonly used in practice, e.g., according to the test methods specified in the embodiments of this application. Unless otherwise specified, the test temperature for each parameter is 25°C.

[0037] The battery mentioned in the embodiments of the present application can refer to a single physical module comprising one or more battery cells to provide a higher voltage and capacity. The batteries mentioned in this application can be, for example, battery cells, battery modules, or battery packs.

[0038] The battery cell is the smallest unit that forms the battery and is solely capable of performing the charging and discharging functions. The battery cell can have the shape of a cylinder, a rectangular body, or other shapes, etc., and the embodiments of the present application are not limited thereto. For example, it shows Fig. 2 a cuboid-shaped structured battery cell 5 as an example.

[0039] The battery cell comprises an electrode assembly and an electrolyte.

[0040] The battery cell may also include an outer casing used to encapsulate the electrode assembly and electrolyte. The outer casing can be a rigid housing, such as a hard plastic casing, an aluminum casing, a steel casing, etc. Alternatively, the outer casing can be a flexible packaging, such as a pouch-like soft casing. The flexible casing can be made of plastic, for example, one or more of the following materials: polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0041] In some embodiments, such as in Fig.As shown in Figure 3, the outer packaging can comprise a housing body 51 and a lid assembly 53. The housing body 51 can include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing body 51 has an opening that communicates with the receiving cavity, and the lid assembly 53 serves to cover the opening to close the receiving cavity. The electrode assembly 52 is encapsulated within the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more and can be adjusted as required.

[0042] The electrode assembly typically comprises a cathode foil and an anode foil, wherein the anode foil is the electrode in which the reaction of uptake or lithiation of lithium ions during charging and release or delthiation of lithium during discharging takes place, and the cathode foil is the electrode in which the reaction of release or delthiation of lithium ions during charging and uptake or lithiation of lithium during discharging takes place.

[0043] In the case of multiple battery cells, the multiple battery cells are connected in series, parallel, or a mixed configuration via a sink component. In some embodiments, the battery may be a battery module; in the case of multiple battery cells, the multiple battery cells are arranged and secured to form a battery module. In some embodiments, the battery may be a battery pack comprising a battery housing and a battery cell, with the battery cell or battery module being housed within the battery housing. In some embodiments, the battery housing may be part of a vehicle chassis structure. For example, parts of the battery housing may be at least part of a vehicle chassis, or parts of the battery housing may be at least part of a crossmember and a longitudinal member of the vehicle.

[0044] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, and the like.

[0045] In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be more than 1, with the exact number being adjustable depending on the application and capacity of the battery module. Fig. Figure 4 is a schematic diagram of battery module 4 as an example. As in Fig. As shown in Figure 4, the multiple battery cells 5 in the battery module 4 can be arranged sequentially along a longitudinal direction of the battery module 4. Of course, they can also be arranged in any other desired manner. Furthermore, the multiple battery cells 5 can be secured by fastening elements.

[0046] Optionally, the battery module 4 can also include a casing with a receiving space in which several battery cells 5 are housed.

[0047] In some embodiments, the battery modules described above can also be assembled into a battery pack, with the number of battery modules contained in the battery pack being adjustable depending on the application and capacity of the battery pack.

[0048] The Fig. 5 and Fig. Figure 6 shows schematic diagrams of battery pack 1 as an example. As in Fig. 5 and Fig.As shown in Figure 6, the battery pack 1 can comprise a battery housing and a plurality of battery modules 4 arranged within the battery housing. The battery housing comprises an upper housing 2 and a lower housing 3, the upper housing 2 serving to cover the lower housing 3 and form an enclosed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged within the battery housing in any desired configuration.

[0049] In recent years, market demand for high-energy-density batteries has increased. To achieve high-density electrode foils and high-energy-density batteries, the industry typically uses a larger particle size distribution to create a densely packed structure. However, increasing the particle size distribution results in a higher proportion of large particles. Studies show that an increased proportion of large particles increases the tortuosity within the electrode foil, thereby increasing the ion transport resistance and inducing ohmic polarization. This can also lead to increased local concentration gradients, causing concentration polarization. Taken together, these factors degrade the kinetic performance of the battery cell, resulting in strong polarization in the later stages of the cycle.

[0050] A first aspect of the present application provides a battery cell comprising a cathode foil, an anode foil and an electrolyte, wherein the cathode foil comprises a cathode collector and a cathode film layer arranged on the surface of at least one side of the cathode collector, and wherein the cathode film layer comprises an active cathode material, and wherein the active cathode material comprises lithium-containing transition metal phosphate particles, wherein (D V90 -D V10 ) / D V50 the number of particles in the cathode film layer is 4 to 8; wherein, based on the total mass of the cathode film layer, the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 60% to 80%.

[0051] (D V90 -D V10 ) / D V50The particle size distribution in the cathode film layer is below 4, indicating a small difference in particle size distribution, leading to poor gradation effects and an insufficient number of smaller particles to fill voids between larger particles. Conversely, (D V90 -D V10 ) / D V50 A particle size distribution greater than 8 within the cathode film layer indicates excessive variation in particle size. This hinders optimal packing density, limits improvements in electrode foil density, and prevents further increases in electrode foil density through improved particle size distribution. Such conditions significantly impair the battery's kinetic performance.

[0052] In the present application, the control of the relationship (D) V90 -D V10 ) / D V50The particle size distribution of 4 to 8 contributes to establishing a rational particle size distribution. This allows smaller particles to fill the voids between larger particles, forming a more compact packing structure that reduces porosity. This increases the packing density of the electrode foil and thus improves the energy density of the battery. However, the significant proportion of larger particles increases the tortuosity within the cathode film layer and lengthens the lithium-ion transport pathways. This leads to local polarization, increases the battery impedance, and impairs the battery kinetics. The present application further addresses this problem by improving the roundness of the particles within the cathode film layer. If the mass fraction of particles with a roundness greater than or equal to 0.75 within the cathode film layer is in the range mentioned above, this facilitates the formation of regular and continuous pore channels, as shown in [reference to relevant figure]. Fig. 1 shown. This reduces the degree of curvature and branching within the pore channels, thereby improving lithium-ion transport efficiency and achieving a balance between the kinetics and cycle life of the battery cell.

[0053] Lithium-containing transition metal phosphate refers to a phosphate material comprising lithium and a transition metal element and can be detected by any known method in this field. For example, it can be detected by a combination of an X-ray diffractometer (XRD) and an energy spectrum analyzer.

[0054] In the present application, the term ‘particle’ refers to particles in the field of view of the cathode film layer at a certain magnification, e.g. 10,000x, with recognizable complete boundaries, whereby defects and scratches may be present within the particles, but no complete boundaries sufficient to subdivide the particles are recognizable within the particles.

[0055] In the present application, the terms “D V10 , D V50 , D V90“These are known meanings in this field and can be tested using established technical methods. For example, the procedure is as follows: Take 2 g of a scraped powder sample from the film layer, add 200 ml of NMP solution and 5 g of sodium dodecyl sulfate (SDS), stir with ultrasound, and disperse at 60 °C for 30 minutes, 60 minutes, 90 minutes, etc. The solutions from the different dispersion times are then measured with a laser particle size analyzer (e.g., Malvern 2000 MasterSizer 2000) according to GB / T 19077-2016 / ISO 13320:2009. If the variations in particle size distribution exceed 5%, the ultrasonic dispersion time is further increased. If the variation in particle size distribution of the solutions from the last two dispersion times is ≤ 5%, the dispersion is considered complete and the test results accurate.”The results can be output to obtain a particle size distribution diagram based on the volume distribution. “D. V10 “, “D V50 “ and “D V90 “ correspond to the particle sizes that represent a percentage of 10%, 50%, 90% in the particle size distribution curve.

[0056] Due to their low hardness, small initial particle size, regular morphology, and excellent mechanical stability, lithium-containing transition metal phosphates exhibit particle size distributions in the rolled cathode film layer that are very similar to those of the original active cathode material. Consequently, the particle size distribution of the active cathode material can be considered equivalent to that of the particles within the cathode film layer. Therefore, examining the particle size distribution of the active cathode material or of particles scraped from the cathode film layer can yield the particle size distribution within the cathode film layer of the present application.

[0057] In some embodiments, the (D V90 -D V10 ) / D V50The particle size within the cathode film layer can optionally be 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8 or any value in a range between any two of these values.

[0058] In some embodiments, the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer, based on the total mass of the cathode film layer, is optionally 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80% or any value in a range between two of these values.

[0059] In the present application, "roundness" is measured as follows: a prepared cathode film or a cathode film removed from a battery is subjected to CP-SEM testing. A random number of points are selected from the cathode film layer for recording; the number is ≥10 and can be 10, 20, 50, 100, etc. Using AVIZO software, particles within the recorded images are identified. The longest inner diameter, the shortest inner diameter, and the area of ​​each particle are also measured. The ratio of the shortest inner diameter to the longest inner diameter serves as the roundness of the particle. All identified particle data are compiled to calculate the roundness and area of ​​each particle.The ratio of the sum of the areas of all particles with a roundness greater than or equal to 0.75 within the cathode film layer to the sum of the areas of all identified particles corresponds to the mass fraction of the particles with a roundness greater than or equal to 0.75 in the cathode film layer.

[0060] In some embodiments, the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 65% to 75%, based on the total mass of the cathode film layer.

[0061] Due to their regular shape, particles with high roundness can be packed more densely after rolling. However, an excessively high proportion can increase particle slippage, compromising the stability of the cathode film layer and reducing the packing density. Therefore, maintaining a mass fraction of particles with a roundness greater than or equal to 0.75 within the aforementioned range facilitates a balance between high packing density and low tortuosity within the cathode film layer.

[0062] In some embodiments, the mass fraction of particles with a roundness of less than or equal to 0.4 in the cathode film layer is 5% to 20%, optionally 10% to 15%, relative to the total mass of the cathode film layer.

[0063] In some embodiments, the mass fraction of particles with a roundness of less than or equal to 0.4 in the cathode film layer is optionally 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or any value in a range between two of these values.

[0064] In the present application, the "roundness" is measured according to the method described above. The ratio of the sum of the areas of all particles with a roundness of less than or equal to 0.4 within the cathode film layer to the sum of the areas of all identified particles is considered to be equivalent to the mass fraction of the particles with a roundness of less than or equal to 0.4 in the cathode film layer.

[0065] During packing, particles with high roundness can exhibit significant gaps between them, limiting further increases in packing density. Consequently, a mixed strategy is employed, utilizing both low- and high-roundness particles. This approach facilitates the interlocking of particles with different shapes and sizes, reducing porosity and forming a more compact packing structure, thereby increasing packing density.

[0066] In some embodiments, (D V90 -D V10 ) / D V50 the particles in the cathode film layer 5 to 7.

[0067] By maintaining this relationship (D V90 -D V10 ) / D V50Within the aforementioned area, both a high energy density and a low tortuosity of the cathode film layer are achieved, further optimizing polarization and lifespan during the battery cycle.

[0068] In some embodiments, the one-sided areal density of the cathode film layer is 200 mg / 1540.25 mm². 2 up to 450 mg / 1540.25 mm 2 .

[0069] In some embodiments, the one-sided areal density of the cathode film layer is optionally 200 mg / 1540.25 mm². 2 , 210 mg / 1540.25 mm 2 , 220 mg / 1540.25 mm 2 , 230 mg / 1540.25 mm 2 , 240 mg / 1540.25 mm 2 , 250 mg / 1540.25 mm 2 , 260 mg / 1540.25 mm 2 , 270 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 290 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 , 310 mg / 1540.25 mm 2 , 320 mg / 1540.25 mm 2 , 330 mg / 1540.25 mm 2, 340 mg / 1540.25 mm 2 , 350 mg / 1540.25 mm 2 , 360 mg / 1540.25 mm 2 , 370 mg / 1540.25 mm 2 , 380 mg / 1540.25 mm 2 , 390 mg / 1540.25 mm 2 , 400 mg / 1540.25 mm 2 , 410 mg / 1540.25 mm 2 , 420 mg / 1540.25 mm 2 , 430 mg / 1540.25 mm 2 , 440 mg / 1540.25 mm 2 , 450 mg / 1540.25 mm 2 or any value within a range between two of these values.

[0070] In the present application, the areal density of the cathode film layer on one side has a meaning known in the art and can be tested by methods known in the art. For example, a cathode foil coated on one side and cold-pressed (in the case of a cathode foil coated on both sides, the cathode film layer on one side can be wiped off first) is taken, punched, and cut into a small disc with an area of ​​S1, weighed, and recorded as M1. Then, the cathode film layer of the cathode foil, which was weighed as described above, is wiped off, and the weight of a collector is weighed and recorded as M0. The areal density of the cathode film layer on one side is given by: (M1 - M0) / S1. To ensure the accuracy of the test results, several sets (e.g., 10 sets) of the samples to be tested can be tested, and an average value can be calculated as the test result.

[0071] The areal density of the cathode film layer has a significant impact on lithium-ion transport rates. Too low an areal density can negatively affect energy density, while too high an areal density can increase ion transport pathways and thus reduce ion transport efficiency. Maintaining the areal density of the cathode film layer within the aforementioned range improves both the energy density and the kinetic performance of the battery.

[0072] In some embodiments, D is V50 The particle size in the cathode film layer is 0.5 µm to 0.9 µm, optionally 0.6 µm to 0.8 µm.

[0073] In some embodiments, D is V50of the particles in the cathode film layer optionally 0.5 µm, 0.51 µm, 0.52 µm, 0.53 µm, 0.54 µm, 0.55 µm, 0.56 µm, 0.57 µm, 0.58 µm, 0.59 µm, 0.6 µm, 0.61 µm, 0.62 µm, 0.63 µm, 0.64 µm, 0.65 µm, 0.66 µm, 0.67 µm, 0.68 µm, 0.69 µm, 0.7 µm, 0.71 µm, 0.72µm, 0.73 µm, 0.74 µm, 0.75 µm, 0.76 µm, 0.77 µm, 0.78 µm, 0.79 µm, 0.8 µm, 0.81 µm, 0.82 µm, 0.83 µm, 0.84 µm, 0.85 µm, 0.86 µm, 0.87 µm, 0.88 µm, 0.89 µm, 0.9 µm or any value in a range between any two of these values.

[0074] The size of the D V50 The particle size distribution in the cathode film layer influences both the packing density and the tortuosity of the cathode film layer. An excessively high density (D) V50 A higher D-value increases the porosity between the particles, making it difficult to increase the packing density of the cathode film layer. Conversely, a D-value that is too low leads to... V50-value to fragmented and interrupted ion conduction pathways between particles, thereby reducing ion transport efficiency and simultaneously hindering electrolyte permeation and blocking ion transport pathways. By maintaining the D V50 By increasing the particle energy density within the cathode film layer within the aforementioned range, the energy density and cycle lifetime of the single cell are further improved.

[0075] In some embodiments, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the first peak of this bimodal distribution being located at 0.45 µm to 0.75 µm.

[0076] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the first peak of this bimodal distribution being located at 0.6 µm to 0.7 µm.

[0077] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the second peak of this bimodal distribution located at 0.6 µm to 0.97 µm.

[0078] In each embodiment, the particle size-volume distribution curve of the particles in the cathode film layer exhibits a bimodal distribution, with the second peak of this bimodal distribution located at 0.7 µm to 0.91 µm.

[0079] In some embodiments, the first peak of the bimodal distribution is located at 0.45 µm, 0.46 µm, 0.47 µm, 0.48 µm, 0.49 µm, 0.5 µm, 0.51 µm, 0.52 µm, 0.53 µm, 0.54 µm, 0.55 µm, 0.56 µm, 0.57 µm, 0.58 µm, 0.59 µm, 0.6 µm, 0.61 µm, 0.62 µm, 0.63 µm, 0.64 µm, 0.65 µm, 0.66 µm, 0.67 µm. 0.68 µm, 0.69 µm, 0.7 µm, 0.71 µm, 0.72 µm, 0.73 µm, 0.74 µm, 0.75 µm or any value in a range between any two of these values.

[0080] In some embodiments, the second peak of the bimodal distribution is located at 0.6 µm, 0.61 µm, 0.62 µm, 0.63 µm, 0.64 µm, 0.65 µm, 0.66 µm, 0.67 µm, 0.68 µm, 0.69 µm, 0.7 µm, 0.71 µm, 0.72 µm, 0.73 µm, 0.74 µm, 0.75 µm, 0.76 µm, 0.77 µm, 0.78 µm, 0.79 µm, 0.8 µm, 0.81 µm, 0.82 µm, 0.83 µm, 0.84 µm, 0.85 µm, 0.86 µm, 0.87 µm, 0.88 µm, 0.89 µm, 0.9 µm, 0.91 µm, 0.92 µm, 0.93 µm, 0.94 µm, 0.95 µm, 0.96 µm, 0.97 µm or any value in a range between any two of these values.

[0081] The volume distribution curve of the particles in the cathode film layer can be determined using the test method described above, in accordance with GB / T 19077-2016. The bimodal particle size distribution curve in the cathode film layer indicates the presence of both large and small particles of varying dimensions within the cathode film layer. The position of the first peak and / or the second peak within the aforementioned range facilitates the filling of voids between large particles by small particles, thereby increasing the electrode film's packing density and further improving the battery's energy density.

[0082] In some embodiments, the cathode film layer comprises a conductive agent, wherein the mass fraction of the conductive agent is 0.5% to 1% relative to the total mass of the cathode film layer.

[0083] In some embodiments, the cathode film layer comprises a conductive agent, wherein, relative to the total mass of the cathode film layer, the mass fraction of the conductive agent is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or any value in a range between two of these values.

[0084] Relative to the total mass of the cathode film layer, the mass fraction of the one-dimensional conductive medium lies within the aforementioned range, so that the cathode film layer exhibits excellent electronic conductivity while simultaneously maintaining a high charge of the active material. This achieves a balance between kinetic power and energy density.

[0085] In some embodiments, the conductive means comprises a one-dimensional conductive means which is optionally one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanofibers.

[0086] In the present application, the term "one-dimensional conductive material" refers to a conductive material that exhibits a distinct one-dimensional spatial structure while maintaining nanoscale dimensions in the other two dimensions. The one-dimensional conductive material includes, but is not limited to, single-walled carbon nanotubes, thin-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanofibers, etc.

[0087] The one-dimensional conductive medium has a fibrous structure with lengths in the micrometer range, enabling the formation of a continuous linear conductive network within the electrode. This allows for an effective conductive network at lower charge levels, thereby reducing the required amount of conductive medium and further improving the battery's energy density.

[0088] In some embodiments, the conductive medium comprises a zero-dimensional conductive medium, which is optionally one or more of conductive carbon black, Ketjen carbon black, and hard carbon.

[0089] In the present application, the term "zero-dimensional conductive agent" refers to conductive materials with a zero-dimensional structure, characterized primarily by dimensions that are approximately the same in all directions and by a point-like structure. Such conductive agents improve the material conductivity through point contacts between the particles.

[0090] The zero-dimensional conductive medium forms a conductive network through point contacts between active materials. Since it typically has a high specific surface area, it effectively fills voids between active materials, further improving the electrode's conductivity and increasing the overall kinetic performance of the battery.

[0091] In some embodiments, the porosity of the cathode film layer is 15% to 25%, optionally 18.2% to 22.9%.

[0092] In some embodiments, the porosity of the cathode film layer is optionally 15%, 15.1%, 15.2%, 15.3%, 15.4%, 15.5%, 15.6%, 15.7%, 15.8%, 15.9%, 16.0%, 16.1%, 16.2%, 16.3%, 16.4%, 16.5%, 16.7%, 16.8%, 16.9%, 17.0%, 17.1%, 17.2%, 17.3%, 17.4%, 17.5%, 17.6%, 17.7%, 17.8%, 17.9%, 18.0%, 18.1%, 18.2%, 18.3%. 18.4%, 18.5%, 18.6%, 18.7%, 18.8%, 18.9%, 19%, 19.1%, 19.2%, 19.3%, 19.4%, 19.5%, 19.6%, 19.7%, 19.8%, 19.9%, 20%, 20.1%, 20.2%, 20.3%, 20.4%, 20.5%, 20.6%, 20.7%, 20.8%, 20.9%, 21%, 21.1%, 21.2%, 21.3%, 21.4%, 21.5%, 21.6%, 21.7%, 21.8%, 21.9% 22%, 22.1%, 22.2%, 22.3%, 22.4%, 22.5%, 22.6%, 22.7%, 22.8%, 22.9%, 23.0%, 23.1%, 23.2%, 23.3%, 23.4%, 23.5%, 23.6%, 23.7%, 23.8%, 23.9%, 24.0%, 24.1%, 24.2%, 24.3%, 24.4%, 24.5%, 24.6%, 24.7%, 24.8%, 24.9%, 25.0% or any value in a range between any two of these values.

[0093] In the present application, the term "porosity" has a meaning well-known in this field and can be tested using methods known in the art. The method is, for example, as follows: using the fully automatic AccuPyc II 1340 real density meter from Micromeritics, USA, and in accordance with the porosity test procedure specified in GB / T 24586-2009, 30 circular disks with a diameter of 14 mm are cut from the cathode foil, and the thickness of the cathode film layer is measured. Based on the principle of gas adsorption, using an inert gas such as helium or nitrogen as the medium, the actual volume of the 30 circular disks (14 mm diameter) is measured. Then, the porosity is determined according to the relationship between the apparent volume of the cathode film layer, calculated on the basis of the disk area, the thickness of the cathode film layer, and the number of disks, and the actual volume.

[0094] By controlling the porosity of the cathode film layer within the aforementioned range, the active cathode material can achieve a high compression density and energy density after roller compaction. A specific porosity facilitates electrolyte wetting of the active cathode material, thereby further optimizing ion transport efficiency, reducing polarization, and extending the battery's cycle life.

[0095] In some embodiments, the lithium-containing transition metal phosphate comprises a component represented by the following general formula: Li x A y Me a M b P 1-c X c Y z , where 0.1 ≤ x ≤ 1.3, 0 ≤ y ≤ 1.3 and 0.9 ≤ x + y ≤ 1.3; 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5 and 0.9 ≤ a + b ≤ 1.5; 0 ≤ c ≤ 0.5; and 3 ≤ z ≤ 5; where A includes one or more of Na, K, Mg; Me includes one or more of Mn, Fe, Co, Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, Ce; X includes one or more of S, Si, Cl, B, C, N; Y includes one or more of O, F.

[0096] In some embodiments, x is optionally 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.15, 1.3 or any value in a range between any two of these values.

[0097] In some embodiments, y is optionally 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.15, 1.3 or any value in a range between any two of these values.

[0098] In some embodiments, x+y is optionally 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3 or any value in a range between any two of these values.

[0099] In some embodiments, a is optionally 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5 or any value in a range between any two of these values.

[0100] In some embodiments, b is optionally 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or any value in a range between any two of these values.

[0101] In some embodiments, a+b is optionally 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5 or any value in a range between any two of these values.

[0102] In some embodiments, c is optionally 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or any value in a range between any two of these values.

[0103] In some embodiments, z is optionally 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5 or any value in a range between any two of these values.

[0104] The lithium-containing transition metal phosphate materials mentioned above exhibit good thermal stability and cycle stability, thereby contributing to improved battery safety and cycle performance.

[0105] In some embodiments, the tortuosity of the cathode film layer is 2.3 to 2.7.

[0106] In some embodiments, the tortuosity of the cathode film layer is optionally 2.3, 2.31, 2.32, 2.33, 2.34, 2.35, 2.36, 2.37, 2.38, 2.39, 2.4, 2.41, 2.42, 2.43, 2.44, 2.45, 2.46, 2.47, 2.48, 2.49, 2.5, 2.51, 2.52, 2.53, 2.54, 2.55, 2.56, 2.57, 2.58, 2.59, 2.6, 2.61, 2.62, 2.63, 2.64, 2.65, 2.66, 2.67, 2.68, 2.69, 2.7 or any value in a range between any two of these values.

[0107] The tortuosity of the cathode film layer within the aforementioned area indicates straighter lithium ion transport pathways within the cathode film layer. This results in shorter diffusion paths for lithium ions within the electrolyte, reduced diffusion resistance, decreased accumulation and concentration gradients of lithium ions within the electrode, and a reduction in the polarization effect. Consequently, superior kinetic performance is achieved, thereby extending the battery's cycle life.

[0108] In some embodiments, the cold-pressed density of the cathode film layer is 2.5 g / cm³. 3 up to 2.75 g / cm³ 3 .

[0109] In some embodiments, the cold-pressed density of the cathode film layer is optionally 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 , 2.6 g / cm³ 3 , 2.61 g / cm³ 3 , 2.62 g / cm³ 3 , 2.63 g / cm³ 3 , 2.64 g / cm³ 3 , 2.65 g / cm³ 3 , 2.66 g / cm³ 3 , 2.67 g / cm³ 3 , 2.68 g / cm³ 3 , 2.69 g / cm³ 3 , 2.7 g / cm³ 3 , 2.71 g / cm³ 3 , 2.72 g / cm³ 3 , 2.73 g / cm³ 3 , 2.74 g / cm³ 3 , 2.75 g / cm³ 3 or any value within a range between two of these values.

[0110] In the present application, the compression density after cold pressing can be verified using methods known in this field. For example, the cathode foil obtained after cold pressing is cut into small circular discs with area S to obtain the mass W1, and the thickness T1 of the cathode foil is measured using a micrometer of hundredths of a millimeter. Then, the cathode film layer of the weighed electrode foil is wiped off, the mass of the collector is weighed and recorded as W2, and the thickness T2 of the collector is measured using a micrometer of hundredths of a millimeter. The compression density PD of the cathode film layer is then calculated as follows: PD = (W1-W2) / [(T1-T2)×S].

[0111] In battery cell manufacturing, after the cathode slurry is applied to the cathode collector, processes such as vacuum drying, cold pressing, cutting, and preparation are carried out to obtain the cathode film. The density achieved during cold pressing differs from that after complete discharge of the formed cathode film layer. This discrepancy arises because the manufactured electrode film experiences slight springback during the charge-discharge cycles, resulting in a cathode film layer density in a fully discharged state that is slightly lower than the density achieved during the initial cold pressing.

[0112] In certain embodiments, the density of the cathode film layer in the fully discharged state is 2.40 g / cm³. 3 up to 2.65 g / cm³ 3 .

[0113] In certain embodiments, the density of the cathode film layer in the fully discharged state is optionally 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 , 2.61 g / cm³ 3 , 2.62 g / cm³ 3 , 2.63 g / cm³ 3 , 2.64 g / cm³ 3 , 2.65 g / cm³ 3 or any value within a range between two of these values.

[0114] In the present application, a fully discharged state refers to a state in which, after the battery has been stored at 25°C for 2 hours and the temperature of the battery has been maintained at 25°C, the battery is discharged to 2.0 V with a constant current of 1 / 3 C, left to rest for 15 minutes and then discharged to 2.0 V with a constant current of 0.04 C.

[0115] In the present application, the density of the cathode film layer in a fully discharged state can be tested using methods known in this field. For example, the battery is placed in an oven environment at 25°C and stored for 2 hours. While maintaining the battery temperature at 25°C, the battery is discharged to 2.0 V at a constant current of 1 / 3 C, allowed to rest for 15 minutes, and then discharged to 2.0 V at a constant current of 0.04 C. The battery is then disassembled to obtain a cathode foil. The remaining electrolyte solution is treated using the solvent dimethyl carbonate. The electrode foil is dried and cut into a small disc with area S to obtain mass W1. Using a micrometer, the thickness T1 of the cathode foil is measured. The cathode film layer is then wiped from the weighed electrode foil.The mass of the collector is weighed and recorded as W2, and the thickness T2 of the collector is measured using a hundredths micrometer; then the compression density PD of the cathode film layer is PD = (W1-W2) / [(T1-T2)×S].

[0116] The pressure density of the cathode film layer is within the above range, which is beneficial for improving the energy density of the battery cell.

[0117] In some embodiments, the cathode collector can be a metal foil or a composite collector. For example, an aluminum foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0118] In some embodiments, the cathode foil can be produced as follows: the aforementioned components for producing the bottom coating, such as lithium-containing transition metal phosphate, conductive agent, binder, and other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a bottom coating slurry; lithium-containing transition metal oxide, conductive agent, binder, and other components are dispersed in a solvent to form a cathode film layer slurry; first, the bottom coating slurry is applied to the cathode collector, followed by drying, cold pressing, and other processes; then, the cathode film layer slurry is applied to the surface of the bottom coating, followed by drying, cold pressing, and other processes to obtain the cathode foil. [Anode foil]

[0119] The anode foil comprises an anode collector and an anode film layer arranged on at least one surface of the anode collector.

[0120] For example, the anode collector has two surfaces that are opposite each other in its own thickness direction, with the anode film layer being arranged on one or two of the two opposite surfaces of the anode collector.

[0121] In some embodiments, the anode collector can be a metal foil or a composite collector. For example, a copper foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0122] In some embodiments, the active anode material may be an active anode material known in the art for use in batteries. The active anode material may, for example, comprise at least one of the following materials: synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate. The silicon-based material may be at least one of monomeric silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloys. The tin-based material may be at least one of monolithic tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as active anode materials in batteries may also be employed.It is possible that only one of these active anode materials is used, or that more than two are used in combination.

[0123] In some embodiments, the anode film layer optionally further comprises a binder. This binder may be at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0124] In some embodiments, the anode film layer optionally further comprises a conductive material. The conductive material can be at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene, and carbon nanofibers.

[0125] In some embodiments, the anode film layer optionally includes further additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0126] In some embodiments, the anode foil can be produced as follows: Dispersing the components described above for the production of the anode foil, such as the active anode material, the conductive agent, the binder and other components, in a solvent (e.g. deionized water) to form an anode slurry; applying the anode slurry to the anode collector and obtaining the anode foil after drying, cold pressing and other processes. [Electrolyte]

[0127] The electrolyte serves as an ion conductor between the cathode foil and the anode foil. The present application does not impose any specific restrictions regarding the type of electrolyte, which can be selected as needed. For example, the electrolyte can be in liquid, gel, or solid form.

[0128] In some embodiments, an electrolyte solution is used for the electrolyte. This electrolyte solution consists of an electrolyte salt and a solvent.

[0129] In some embodiments, the electrolyte salt may be at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(trifluorosulfonyl) amide, lithium bis(trifluoromethanesulfonyl) amide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalic acid borate, lithium di(oxalic acid) borate, lithium difluorodioxygenophosphate and lithium tetrafluorooxalic acid phosphate.

[0130] In some embodiments, the solvent may be at least one of ethylidene carbonate, propylidene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylenepropyl carbonate, ethylenepropyl carbonate, butylidene carbonate, ethylidene fluorocarbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0131] In some embodiments, the electrolyte optionally includes an additive. This additive may, for example, include a film-forming additive for the negative electrode and a film-forming additive for the positive electrode, and may also include an additive that can improve certain battery properties, such as an additive to improve the battery's overcharge performance, an additive to improve the battery's high- or low-temperature performance, etc. [Separator film]

[0132] In some embodiments, the battery cell further comprises a separating film. The present application does not impose any specific restrictions regarding the type of separating film, and any known separating film with a porous structure and good chemical and mechanical stability can be selected.

[0133] In some embodiments, the separating film material can be at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separating film can be a single-layer film or a multi-layer composite film without any particular restriction. If the insulating film is a multi-layer composite film, the materials of the layers can be the same or different without any particular restriction. [Battery cell]

[0134] In some embodiments, the cathode foil, the anode foil and the separating element can be assembled into an electrode assembly by a winding process or a stacking process.

[0135] In some embodiments, the battery cell may include an outer packaging. The outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0136] In some embodiments, the outer packaging of the battery cell can be a rigid casing, such as a hard plastic casing, an aluminum casing, a steel casing, etc. The outer packaging of the battery cell can also be a flexible casing, such as a bag-like soft casing. The flexible casing can be made of plastic, and examples of such plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0137] The present application does not subject the shape of the battery cell to any particular restrictions, so that it can be cylindrical, square or in any other shape. For example, shows Fig. 3 a square structured battery cell 5 as an example.

[0138] In some embodiments, such as in Fig.As shown in Figure 3, the outer packaging can comprise a housing body 51 and a lid assembly 53. The housing body 51 can include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing body 51 has an opening that communicates with the receiving cavity, and the lid assembly 53 can cover the opening to close the receiving cavity. The cathode foil, the anode foil, and the separator film can be assembled into an electrode assembly 52 by a winding or stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte solution permeates the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, selected by those skilled in the art according to the specific practical requirements. [Battery device]

[0139] One embodiment of the present application further provides a battery device comprising a battery cell provided by the embodiment of the present application. In some embodiments, the battery device comprises one or more battery modules, a battery pack, and an energy storage device.

[0140] In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be 1 or more than 1, the exact number being selected by experts in this field depending on the application and capacity of the battery module.

[0141] Fig. Figure 4 shows a battery module 4 as an example. With reference to Fig.4. The multiple battery cells 5 in the battery module 4 can be arranged sequentially along a longitudinal direction of the battery module 4. Of course, they can also be arranged in any other desired way. Furthermore, the multiple battery cells 5 can be fastened by means of fastening elements.

[0142] Optionally, the battery module 5 can also include a casing with a receiving space in which several battery cells 5 are housed.

[0143] In some embodiments, the battery cells can be assembled into a battery pack, and the number of battery cells contained in the battery pack can be 1 or more than 1, with the exact number being selected by experts in this field depending on the application and capacity of the battery module.

[0144] Fig. 5 and Fig. Figure 6 shows a battery pack 1 as an example. As in Fig. 5 and Fig.As shown in Figure 6, the battery pack 1 can comprise a battery housing and a plurality of battery modules 4 arranged within the battery housing. The battery housing comprises an upper housing 2 and a lower housing 3, wherein the upper housing 2 can cover the lower housing 3 and form an enclosed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged within the battery housing in any desired configuration. [Power-consuming device]

[0145] Furthermore, one embodiment of the present application provides a power-consuming device comprising at least one battery cell, one battery module, and one battery pack, as provided by the embodiments of the present application. The battery cell, battery module, or battery pack can be used as a power source for the power-consuming device or as an energy storage unit for the power-consuming device. The power-consuming device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0146] Depending on requirements, the power-consuming device can be a battery cell, a battery module or a battery pack.

[0147] Fig. Figure 7 shows an example of the power-consuming device. The power-consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the battery cell of this power-consuming device, a battery pack or battery module can be used.

[0148] Another example of such a device is a mobile phone, a tablet, a laptop, etc. The device usually needs to be light and thin and can use a battery cell as a power source. Examples of implementation

[0149] The following describes exemplary embodiments of the present application. The embodiments described below are exemplary, serve to explain the present application, and cannot be construed as limiting the present application. Unless specific techniques or conditions are indicated in the exemplary embodiments, they correspond to the techniques or conditions described in the relevant literature or to the information in the product specification. The reagents or instruments used without manufacturer identification are all commercially available products. Example 11) Production of the cathode foil

[0150] Preparation of the cathode film layer slurry: Mixing the lithium iron phosphate particles (LiFePO4) with a D V50 of 0.7 µm and a (D V90 -D V10 ) / D V50-value of 6.0, conductive carbon black, a conductive medium carbon nanotubes and a binder PVDF in a mass ratio of 98:0.4:0.6:1, addition of the solvent NMP and stirring in a vacuum mixer until the system is homogeneous, resulting in the cathode film layer slurry, wherein, based on the total mass of the lithium iron phosphate, the particles with a roundness of ≥0.75 constitute 70% of the lithium iron phosphate, while particles with a roundness of ≤0.4 constitute 15%; The cathode film layer slurry is applied evenly to a surface of the floor coating facing away from the cathode collector, with a one-sided coating weight of 300 mg / 1540.25 mm². 2 The coating is air-dried at room temperature before being placed in an oven for further drying. The cathode film is then obtained by cold pressing, and the cold-pressed density of the cathode film layer is 2.7 g / cm³.3 The one-sided coating mass specified here excludes the solvent mass and corresponds exclusively to the solid mass within the coating.

[0151] Cutting the electrode foil (one to two division): The cathode foil is cut on a cutting machine at a speed of 0.5 m / s. The cutting blade material is steel, and the cutting machine operates with a vacuum of -10 kPa.

[0152] Cutting the electrode foil: The cut electrode foils undergo a winding and cutting process. The winding speed is 0.6 m / s, with each core being 3 m long. The cutting blade is made of steel, and the vacuum inside the winding machine is -10 kPa. 2) Production of the anode foil

[0153] The active anode material graphite, the binder polyvinyl alcohol, and the conductive agent SP-Li are thoroughly mixed and milled in a ball mill in a deionized aqueous solvent system at a mass ratio of 90:5:5 to form the anode slurry. The anode slurry is then applied to both sides of the copper foil surface with a single-sided coating mass of 140 mg / 1540.25 mm². 2 applied. Vacuum drying takes place overnight at 110°C to preserve the anode foil. 3) Production of the release film

[0154] Using a polyethylene film with a thickness of 13 µm as a separating film. 4) Preparation of the electrolyte solution

[0155] LiPF6 is dissolved in a mixture of ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate (DMC) in a volume ratio of 1:1:1 to form a homogeneous solution, yielding an electrolyte with a LiPF6 concentration of 1 mol / L. 5) Assembling the battery

[0156] The components are stacked in the following order: separator film – anode foil – separator film – cathode foil. One end of the cathode foil, one end of the anode foil, and one end of each separator film are attached to the discharge roller, while the other ends are stacked on top of each other and secured to the winding shaft. A motor rotates the winding shaft to wind the cathode foil, the anode foil, and the two separator films, creating a wound bare battery core. The bare battery core is placed in an outer casing, filled with the aforementioned electrolyte solution, and sealed to form the battery cell.

[0157] The manufacturing process of embodiment 2 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.5 µm, wherein (D V90 -D V10 ) / D V50 8.0; and where the cold-pressed density of the cathode film layer is 2.74 g / cm³ 3 amounts.

[0158] The manufacturing process of embodiment 3 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.6 µm, wherein (D V90 -D V10 ) / D V50 7.0; and where the cold-pressed density of the cathode film layer is 2.72 g / cm³ 3 amounts.

[0159] The manufacturing process of embodiment 4 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.8 µm, wherein (D V90 -D V10 ) / D V50 5.0; and where the cold-pressed density of the cathode film layer is 2.68 g / cm³ 3 amounts.

[0160] The manufacturing process of embodiment 5 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.9 µm, where (D V90 -D V10 ) / D V50 4.0; and where the cold-pressed density of the cathode film layer is 2.66 g / cm³ 3amounts.

[0161] The manufacturing process of embodiment 6 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.66 µm in diameter, with particles with a roundness of ≥0.75 comprising 80% of the lithium iron phosphate, while particles with a roundness of ≤0.4 comprise 10%; the cold-pressed density of the cathode film layer is 2.67 g / cm³ 3 .

[0162] The manufacturing process of embodiment 7 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50The lithium iron phosphate particles are 0.68 µm in diameter, with particles having a roundness of ≥0.75 comprising 75% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.69 g / cm³. 3 .

[0163] The manufacturing process of embodiment 8 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.72 µm in diameter, with particles having a roundness of ≥0.75 comprising 65% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.68 g / cm³. 3 .

[0164] The manufacturing process of embodiment 9 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.74 µm in diameter, with particles having a roundness of ≥0.75 comprising 60% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.66 g / cm³. 3 .

[0165] The manufacturing process of embodiment 10 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.65 µm in diameter, with the particles having a roundness of ≤0.4 µm representing 0% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.65 g / cm³.3 .

[0166] The manufacturing process of embodiment 11 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.67 µm in diameter, with particles having a roundness of ≤0.4 comprising 5% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.66 g / cm³. 3 .

[0167] The manufacturing process of embodiment 12 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50The lithium iron phosphate particles are 0.69 µm in diameter, with particles having a roundness of ≤0.4 comprising 10% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.68 g / cm³. 3 .

[0168] The manufacturing process of embodiment 13 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.73 µm in diameter, with particles having a roundness of ≤0.4 comprising 20% ​​of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.67 g / cm³. 3 .

[0169] The manufacturing process of embodiment 14 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, the one-sided coating mass of the cathode film layer slurry is 450 mg / 1540.25 mm². 2 ; the cold-pressed density of the cathode film layer is 2.60 g / cm³ 3 .

[0170] The manufacturing process of embodiment 15 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, the one-sided coating mass of the cathode film layer slurry is 380 mg / 1540.25 mm². 2 ; the cold-pressed density of the cathode film layer is 2.66 g / cm³ 3 .

[0171] The manufacturing process of embodiment 16 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, the one-sided coating mass of the cathode film layer slurry is 250 mg / 1540.25 mm². 2 ; the cold-pressed density of the cathode film layer is 2.72 g / cm³ 3 .

[0172] The manufacturing process of embodiment 17 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry application step, the one-sided coating mass of the cathode film layer slurry is 200 mg / 1540.25 mm². 2 ; the cold-pressed density of the cathode film layer is 2.75 g / cm³ 3 .

[0173] The manufacturing process of embodiment 18 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.9 µm; the cold-pressed density of the cathode film layer is 2.63 g / cm³. 3 .

[0174] The manufacturing process of embodiment 19 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles measure 0.85 µm; the cold-pressed density of the cathode film layer is 2.67 g / cm³. 3 .

[0175] The manufacturing process of embodiment 20 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 The lithium iron phosphate particles are 0.5 µm; the cold-pressed density of the cathode film layer is 2.73 g / cm³. 3 .

[0176] The manufacturing process of Comparative Example 1 is essentially identical to that of Exemplary Example 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, the particles with a roundness of ≥0.75 constitute 50% of the lithium iron phosphate; the cold-pressed density of the cathode film layer is 2.67 g / cm³. 3 .

[0177] The manufacturing process of comparative example 2 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, particles with a roundness of ≥0.75 constitute 90% of the lithium iron phosphate, while particles with a roundness of ≤0.4 constitute 0%; the cold-pressed density of the cathode film layer is 2.58 g / cm³. 3 .

[0178] The manufacturing process of comparative example 3 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.5 µm, wherein (D V90 -D V10 ) / D V50 9.0; the cold-pressed density of the cathode film layer is 2.71 g / cm³ 3 .

[0179] The manufacturing process of comparative example 4 is essentially identical to that of embodiment 1 and differs only in the production of the cathode foil. During the cathode film layer slurry manufacturing step, D V50 the lithium iron phosphate particles 0.9 µm, where (D V90 -D V10 ) / D V50 3.0; the cold-pressed density of the cathode film layer is 2.50 g / cm³ 3 . Performance test 1. Roundness test procedure

[0180] At 25°C, a CP-SEM examination is performed on cut cathode films prepared from each embodiment and comparison example. A random number of points is selected for acquisition; the number is ≥10 and can be 10, 20, 50, 100, etc. Using AVIZO software, particles within the acquired images are identified, and the shortest diameter, longest diameter, and area of ​​each particle are measured. Roundness = shortest diameter / longest diameter. The ratio of the sum of the areas of all particles with a roundness greater than or equal to 0.75 to the sum of the areas of all identified particles corresponds to the mass fraction of particles with a roundness greater than or equal to 0.4 in the cathode film layer. Similarly, the mass fraction of particles with a roundness less than or equal to 0.3 in the cathode film layer is obtained. 2. Porosity testing procedure

[0181] At 25°C, the cut cathode foils produced from each embodiment and comparison example are taken. The electrode foils are cut into small discs with a diameter of 14 mm. The samples are measured according to GB / T 24586-2009 using a vacuum density meter (e.g., Micromeritics AccuPyc II 1340 fully automatic true density meter). At least 30 samples are tested, and the mean value is determined as the final result. 3. Tortuosity testing procedure

[0182] At 25°C, the cut cathode foils prepared for each embodiment and comparison example are taken and punched into 14 mm discs. The cathode foils are assembled into symmetrical batteries in a glovebox (humidity ≤1 ppm). After filling with the electrolyte, the batteries are left to rest for at least 12 hours to ensure complete impregnation of the foils with the electrolyte. The impedance changes are checked using an EIS test with the following parameters: upper frequency limit 1 kHz, lower frequency limit 500 mHz, interference voltage 5 mV, and symmetrical cell voltage range -1 V to 1 V. The adjusted test data yielded the ion diffusion resistance Rion. The electrolyte formulation is as follows: an organic solvent is prepared by mixing dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), and ethylene carbonate (EC) in a weight ratio of 4:3:3.LiPF6 is then dissolved in this organic solvent to form an electrolyte solution with a concentration of 1.0 mol / L.

[0183] The tortuosity of the electrode foil is calculated as follows: the area A (1.5386 cm²) 2 ) of the above-mentioned small disk, its thickness d (cm), the electrolyte conductivity k (S / m), the porosity ε of the electrode foil and the ion diffusion resistance Rion (Ω) are introduced into the following to determine the tortuosity of the electrode foil. τ=ε×k×Rlon×Ad 4. Test procedure for the energy density of the battery

[0184] All battery cells from the exemplary embodiments and comparative examples are left to rest for 2 hours at 25°C to ensure a uniform temperature of 25°C. The battery cell is then charged at 25°C at 1 / 3 C until the cut-off voltage of 3.65 V is reached, and charging continues at a constant voltage at this cut-off voltage until the current reaches 0.05 C, at which point the charging process is stopped (where C represents the nominal capacity of the battery cell). After being stored at 25°C for 1 hour, the battery cell is discharged at 25°C at 0.33 C until the discharge cut-off voltage reaches 2.5 V, and the total discharge energy of the battery cell is recorded as E0. The mass of the battery cell is measured as M0.

[0185] The mass energy density of the battery cell = discharge energy E0 of the battery cell / mass M0 of the battery cell. 5. Cycle performance test procedure

[0186] At 25°C, individual cells manufactured from each embodiment and comparison example are charged with a constant current of 1C to 50% SOC, then charged with 0.87C to 80% SOC, and then charged with 0.33C to a cutoff voltage of 3.65V. Charging then continues at this cutoff voltage as a constant voltage until the current reaches 0.05C, at which point the cells are discharged with a constant current of 1C to the discharge cutoff voltage of 2.5V. This constitutes one charge-discharge cycle, during which the discharge capacity of the battery cell is recorded as the initial cycle discharge capacity E1. This charge-discharge cycle is repeated 1000 times. The discharge capacity of the battery cell at this point is recorded as E2. The capacity maintenance rate @1000Cs is calculated as E2 / E1 × 100%.

[0187] The battery cells for each embodiment and each comparative example are manufactured according to the procedure described above. The specific parameters and performance data are listed in Tables 1 and 2 below. Table 1 (D V90 -D V10 ) / D V50 D V50 / µm Proportion of particles with a roundness of ≥0.75 / wt.% Proportion of particles with a roundness of ≤0.4 / wt.% One-sided surface density g / cm² 3 First peak / µm Second peak / µm Example 1 6,0 0,7 70% 15% 300 0,65 0,85 Example 2 8,0 0,5 70% 15% 300 0,55 0,73 Example 3 7,0 0,6 70% 15% 300 0,6 0,79 Example 4 5,0 0,8 70% 15% 300 0,7 0,91 Example 5 4,0 0,9 70% 15% 300 0,75 0,97 Example 6 6,0 0,66 80% 10% 300 0,65 0,85 Example 7 6,0 0,68 75% 15% 300 0,65 0,85 Example 8 6,0 0,72 65% 15% 300 0,65 0,85 Example 9 6,0 0,74 60% 15% 300 0,65 0,85 Example 10 6,0 0,65 70% 0% 300 0,65 0,85 Example 11 6,0 0,67 70% 5% 300 0,65 0,85 Example 12 6,0 0,69 70% 10% 300 0,65 0,85 Example 13 6,0 0,73 70% 20% 300 0,65 0,85 Example 14 6,0 0,7 70% 15% 450 0,65 0,85 Example 15 6,0 0,7 70% 15% 380 0,65 0,85 Example 16 6,0 0,7 70% 15% 250 0,65 0,85 Example 17 6,0 0,7 70% 15% 200 0,65 0,85 Example 18 6,0 0,9 70% 15% 300 0,85 0,95 Example 19 6,0 0,85 70% 15% 300 0,8 0,88 Example 20 6,0 0,5 70% 15% 300 0,45 0,6 Comparative example 1 6,0 0,7 50% 15% 300 0,65 0,85 Comparative example 2 6,0 0,7 90% 0% 300 0,65 0,85 Comparative example 3 9,0 0,5 70% 15% 300 0,45 0,6 Comparative example 4 3,0 0,9 70% 15% 300 0,75 0,97 Table 2 Porosity / % Density in fully discharged state (g / cm³) 3 Tortuosity Mass energy density wh / kg Capacity maintenance rate @1000C1s Example 1 20,70% 2,57 2,45 185 95,50% Example 2 18,20% 2,6 2,7 192 94,60% Example 3 19,30% 2,58 2,58 188 95,30% Example 4 21,80% 2,53 2,39 181 95,70% Example 5 22,90% 2,52 2,31 179 95,90% Example 6 21,30% 2,52 2,34 180 95,80% Example 7 21,00% 2,54 2,4 183 95,65% Example 8 20,20% 2,53 2,55 181 95,25% Example 9 19,50% 2,52 2,5 178 95,35% Example 10 20,00% 2,5 2,37 176 95,90% Example 11 20,20% 2,52 2,39 178 95,70% Example 12 20,50% 2,53 2,43 182 95,55% Example 13 20,40% 2,52 2,41 180 95,60% Example 14 21,80% 2,45 2,45 195 94,10% Example 15 21,40% 2,52 2,43 189 94,60% Example 16 20,40% 2,58 2,46 180 95,70% Example 17 20,00% 2,61 2,5 174 95,80% Example 18 22,80% 2,48 2,37 173 96,00% Example 19 21,60% 2,52 2,42 180 95,70% Example 20 18,50% 2,59 2,63 190 94,30% Comparative example 1 21,20% 2,52 2,7 180 93,80% Comparative example 2 22,50% 2,43 2,42 165 95,50% Comparative example 3 18,30% 2,57 3,3 186 92,10% Comparative example 4 23,70% 2,38 2,39 160 95,60%

[0188] By comparing the exemplary embodiments and the comparative examples, it is evident that, by (D V90 -D V10 ) / D V50If the particle size distribution in the cathode film layer is 4 to 8, and the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 60% to 80%, batteries can be enabled to achieve a high energy density while reducing the deterioration of tortuosity caused by a large particle size distribution, thereby improving the cycle life of the battery.

[0189] A comparison of embodiments 1 to 5 shows that if (D V90 -D V10 ) / D V50 the particle in the cathode film layer 5 to 7 is and D V50 The particle size is 0.6 µm to 0.8 µm, achieving a balance between tortuosity and density in the cathode foil, which is beneficial for improving the mass energy density and cycle life of the battery.

[0190] From the comparison between embodiment 1 and embodiments 6 to 9, it is evident that if the mass fraction of particles with a roundness greater than or equal to 0.75 in the cathode film layer is 65% to 75%, an equilibrium between the mass energy density and the cycle life of the battery is achieved.

[0191] From the comparison between embodiment 1 and embodiments 10 to 13, it is evident that if the mass fraction of particles with a roundness of less than or equal to 0.4 in the cathode film layer is 5% to 20%, preferably 10% to 15%, the improvement in the energy density of the battery is promoted.

[0192] From the comparison between embodiment 1 and embodiments 14 to 17, it is evident that if the one-sided areal density of the cathode film layer is 200 mg / 1540.25 mm² 2 up to 450 mg / 1540.25 mm 2This results in a high energy density of the battery and allows for optimization of the cycle life.

[0193] From the comparison between embodiment 1 and embodiments 18 to 20, it is evident that if D V50 The particle size in the cathode film layer is 0.6 µm to 0.8 µm, reducing the tortuosity of the cathode film layer and extending the cycle life of the battery.

[0194] It should be noted that the present application is not limited to the embodiments mentioned above. The embodiments mentioned above are only examples, and embodiments within the scope of the technical solution of the present application that have essentially the same composition as the technical idea and have the same effect are included in the technical scope of the present application. Furthermore, within the scope of the present application, other possibilities for constructing the embodiments by combining some of the constituent elements of the embodiments and applying various deformations to the embodiments that a person skilled in the art can imagine without departing from the subject matter of the present application are also included. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] GB / T 19077-2016

[0081]

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