Positive electrode plate, electrochemical device comprising the positive electrode plate, and electrochemical device

Abstract

Positive electrode plate comprising a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, characterized in that the positive electrode active material layer comprises a positive electrode active material that includes a ternary positive electrode active material; The particle size change rate of the positive electrode active material, the roughness of the positive electrode plate, and the porosity of the positive electrode plate satisfy the following relationship: 1.2 ≤ D / ( R / 5 + P / 2 ) ≤ 3.5 ; where D is the particle size change rate of D V 50% before and after the positive electrode active material is held at a pressure of 35 kN for 30 seconds, and D V50 is a particle size that corresponds to 50% of a cumulative volume distribution percentage of the positive electrode active material; R is the roughness of the positive electrode plate in nm; and P is the porosity of the positive electrode plate in %.

Description

BACKGROUNDTechnical field

[0001] The present invention relates to the field of electrochemical technology, in particular to a positive electrode plate or a positive pole piece, an electrochemical device comprising the positive electrode plate, and an electrical or electronic device. Description of the state of the art

[0002] Lithium-ion batteries have the advantages of high specific energy, light weight, long cycle life, and no memory effect. They are used in various civil electrical appliances and electric vehicles, energy storage, mobile power, and other fields. With the wide range of applications of lithium-ion batteries, the low-temperature discharge performance of lithium-ion batteries has become increasingly demanding.

[0003] At low temperatures, the decrease in the lithium-ion transfer rate is the main reason for the decrease in the discharge performance of lithium-ion batteries. The properties of the positive electrode active material, the negative electrode active material, the electrolyte solution, and the current collector can all cause a decrease in the lithium-ion transfer rate. The influence of the positive electrode active material is relatively more important. At low temperatures, the decrease in the conductivity of the electrolyte solution leads to a decrease in the transport rate of lithium ions in the positive electrode active material and a decrease in the discharge capacity of the lithium-ion battery at low temperatures.For ternary positive electrode active materials with high nickel content, the conductivity of lithium ions decreases at low temperatures and also leads to an increase in resistance, resulting in a decrease in the discharge performance of the battery and more pronounced problems during rapid discharges.

[0004] Therefore, it is of great importance to develop low-temperature lithium-ion batteries that can be used in severe cold or northern fields to expand the application areas and scope of lithium-ion batteries. SUMMARY

[0005] An object of the present invention is to overcome the disadvantages of the prior art and to provide a positive electrode plate, an electrochemical device comprising the positive electrode plate, and an electrical device. The capacity retention rate at low temperatures and the performance of the electrochemical device at high discharge rates at low temperatures are said to be significantly improved after the positive electrode plate has been attached to the electrochemical device. The invention is defined by the features of the independent claims. Advantageous embodiments are subject to the dependent claims.

[0006] To achieve the above-mentioned objective, the present invention, in a first aspect of the present invention, provides a positive electrode plate comprising a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector. The positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a ternary positive electrode active material. A particle size change rate of the positive electrode active material, the roughness of the positive electrode plate, and a porosity of the positive electrode plate satisfy the following relationship: 1.2≤D / (R / 5+P / 2)≤3.5 where D is the particle size change rate D V 50 in % before and after the positive electrode active material is held at a pressure of 35 KN for 30 seconds, and D V50 is a particle size corresponding to 50% of a cumulative volume distribution percentage of the positive electrode active material.

[0007] R is the roughness of the positive electrode plate in nm.

[0008] P is the porosity of the positive electrode plate in %.

[0009] In a preferred embodiment of the present invention, the particle size change rate of the positive electrode active material, the roughness of the positive electrode plate, and the porosity of the positive electrode plate satisfy the following relationship: 1.7≤D / (R / 5+P / 2)≤2.5.

[0010] In a preferred embodiment of the present invention, the particle size change rate (D) of the positive electrode active material is between 60% and 90%.

[0011] In a preferred embodiment of the present invention, the particle size change rate (D) of the positive electrode active material is between 65% and 80%.

[0012] In a further preferred embodiment of the present invention, the roughness (R) of the positive electrode plate is in the range of 80 nm to 200 nm.

[0013] In a further preferred embodiment of the present invention, the roughness (R) of the positive electrode plate is in the range of 100 nm to 150 nm.

[0014] In a preferred embodiment of the present invention, the porosity (P) of the positive electrode plate is in the range of 15% to 35%.

[0015] In a further preferred embodiment of the present invention, the porosity (P) of the positive electrode plate is in the range of 18% to 25%.

[0016] In a preferred embodiment of the present invention, the particle size (D V 50) of the positive electrode active material from 3 µm to 8 µm.

[0017] In a preferred embodiment of the present invention, the ternary positive electrode active material has the formula LiNi x Co y Mn (1-x-y) O2, where 0.7≤x < 1.0 <y≤0,3, und 0<x+y< 1.

[0018] In a second aspect, the invention provides an electrochemical device comprising the positive electrode plate as described above.

[0019] In a third aspect, the present invention provides an electrical device comprising the electrochemical device as described above.

[0020] The invention has the following advantageous effects.

[0021] The present invention provides a positive electrode plate, an electrochemical device comprising the positive electrode plate, and an electrical device. By controlling the roughness of the positive electrode plate, the porosity of the positive electrode plate, and the particle size change rate of the positive electrode active material, the present invention can significantly improve the capacity retention rate at low temperatures and the discharge performance of the electrochemical device at high temperatures after the positive electrode plate is attached to the electrochemical device. DESCRIPTION OF THE DESIGNS

[0022] To clarify the objectives, technical solutions, and advantages of the embodiments of the invention, the technical solutions in the embodiments of the invention are described clearly and completely below. Of course, the described examples are only a part of the invention and not all examples. Based on the examples of the invention, all other examples that a person skilled in the art can deduce without inventive effort are also within the scope of the invention.

[0023] The present invention includes, among the technical features described openly, both a closed technical solution consisting of the mentioned features and an open technical solution containing the mentioned features.

[0024] In the present invention, reference is made to numerical ranges, which, unless otherwise stated, are to be considered continuous and include both the minimum and maximum values ​​of the range, as well as any value between the minimum and maximum values. When a range refers to an integer, it also includes any integer between the minimum and maximum values ​​of the range. When multiple ranges are specified to describe a feature or characteristic, the ranges may also be combined. In other words, unless otherwise stated, all ranges disclosed herein also include all subranges contained therein.

[0025] In the present invention, the specific methods for dispersing and stirring the treatment are not particularly limited.

[0026] Unless the reagents or instruments used in the invention are specified by the manufacturer, they are commercially available products.

[0027] It should be noted that in the content of the present application, the present application is explained by taking a lithium-ion secondary battery as an example of an electrochemical device, but the electrochemical device of the present application is not limited to the lithium-ion secondary battery. Positive electrode plate or positive pole piece

[0028] One example of the present invention provides a positive electrode plate comprising a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector. The positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a ternary positive electrode active material.

[0029] The particle size change rate D of the positive electrode active material, the roughness R of the positive electrode plate, and the porosity P of the positive electrode plate satisfy the following relationship: 1.2≤D / (R / 5+P / 2)≤3.5

[0030] In the above relationship, D is the particle size change rate of D V50% before and after the positive electrode active material is held at a pressure of 35 kN for 30 seconds. R is the roughness of the positive electrode plate in nm, and P is the porosity of the positive electrode plate in %.

[0031] In the present invention, the particle size change rate (D) of the positive electrode active material is calculated from the change in particle size (D V 50) of the positive electrode active material before and after holding for 30 seconds at a pressure of 35 KN. In the present application, the positive electrode active material comprises primary particles and / or secondary particles, where "primary particle" refers to a primary structure composed of individual particles, i.e., single-crystal particles, and "secondary particle" refers to an aggregate in which primary particles are aggregated by physical or chemical bonding between primary particles, i.e., a secondary structure.

[0032] The particle size change rate of the positive electrode active material is related to the particle strength of the positive electrode active material and the degree of secondary particle content (which also corresponds to the degree of single crystallization). When the positive electrode active material is subjected to pressure, the secondary particles of the positive electrode active material may be broken into a plurality of smaller particles, or deformation or breakage of the primary particles and / or secondary particles may occur. Generally, when the particle size change rate of the positive electrode active material is low, it means that the higher the strength of the representative particle, the more stable the layered structure, or the lower the proportion of secondary particles, the higher the degree of single crystallization.The higher particle size change rate means a relatively low particle strength or a relatively high proportion of secondary particles.

[0033] The particle size change rate of the positive electrode active material should be within an appropriate range. For the positive electrode active material, a higher particle size change rate tends to mean that there are more pores and voids within the positive electrode active material layer, which may be caused by the rolling step during the preparation of the positive electrode plate. The pores and voids within the positive electrode active material layer can be microscopic cracks, voids, or cavities within the positive electrode active material particles, or gaps between the particles. The presence of pores and voids shortens the diffusion path of ions inside the particles, increases the intercalation / deintercalation rate of ions, and improves the low-temperature discharge performance of the lithium-ion battery.In addition, the positive electrode active material undergoes volume expansion and contraction during the charging and discharging of the lithium-ion battery, and the higher particle size change rate can provide more space to accommodate the volume change, reducing the risk of stress concentration and damage, and thus improving the electrochemical performance of the positive electrode plate after long-term low-temperature cycling.

[0034] The particle size change rate of the positive electrode active material should not be too high. The positive electrode active material requires appropriate particle thickness to ensure the material has good structural strength and stability. At low temperatures, the material inside the battery tends to become brittle. A positive electrode active material with an excessively high particle size change rate cannot provide sufficient mechanical support due to its low structural strength and stability, resulting in structural damage to the positive electrode plate and thus deteriorating the battery's electrochemical performance at low temperatures. In addition, in a low-temperature environment, the diffusion rate of ions slows down, leading to a reduction in the battery's electrochemical reaction rate.If the particle size change rate of the positive electrode active material is too high, the proportion of secondary particles may be too large, resulting in a decrease in the density of the active material and impairing charge and ion transport in the positive electrode plate, thereby reducing the battery's low-temperature capacity. The particle size change rate of the positive electrode active material should not be too low. A particle size change rate that is too low is often related to the heterogeneity of the internal structure of the particles. Too strong a bond between the transition metal and oxygen leads to an increase in the lithium ion transport potential. A particle size change rate that is too low may indicate that there are too few pores and voids within the positive electrode active material layer.An excessively long diffusion path for ions within the particles is not conducive to the high discharge performance of lithium-ion batteries at low temperatures. Furthermore, if the particle size change rate is too low, the stress generated by the positive electrode plate (lattice expansion / contraction) during repeated charging and discharging tends to concentrate locally, which is not conducive to long-term storage and use of the cell at low temperatures.

[0035] The roughness of the positive electrode plate and the porosity of the positive electrode plate also have a great influence on the electrochemical performance of the battery at low temperatures.

[0036] The roughness of the positive electrode plate affects the contact performance between the electrode and the electrolyte solution. In a low-temperature environment, the electrochemical reaction rate is slow. Appropriate roughness means that the contact area between the positive electrode active material layer in the positive electrode plate and the electrolyte solution is relatively larger, which facilitates the transport of ions in the positive electrode plate, promotes the electrochemical reaction at low temperatures, and thus improves the capacity retention rate of the battery at low temperatures. The roughness of the positive electrode plate should not be too low, otherwise it is difficult to establish a uniform and complete contact area between the active particles and the electrolyte solution to ensure the normal migration of lithium ions.However, excessive roughness can lead to excessive accumulation of the electrolyte solution on the surface of the highly oxidizing positive electrode active material and excessive side reactions of the electrolyte solution on the surface of the positive electrode active material, thereby reducing the battery's capacity retention rate. Excessively high roughness can also lead to uneven distribution of the electric field on the surface of the positive electrode plate, aggravating the phenomenon of electrode polarization. Especially at low temperatures, the degree of electrode polarization generally increases, which impairs the battery's electrochemical performance. In addition, excessive roughness can also mean that there are too many pores in the positive electrode plate, resulting in reduced electrical connection and increased resistance, which impairs the battery's low-temperature performance.

[0037] The porosity of the positive electrode plate mainly affects the diffusion space of the electrolyte solution and the contact area with the positive electrode active material. Appropriate porosity can increase the contact area between the electrolyte solution and the positive electrode active material, promote ion transport and reaction, and improve the electrochemical reaction efficiency at low temperatures. However, excessive porosity is not conducive to increasing the cell's energy density and also has the problem of excessive electrolyte solution consumption. Excessive porosity can lead to a reduction in the electrical connection within the positive electrode plate, resulting in a decrease in the conductivity and an increase in the resistance of the positive electrode plate, thus affecting the high-performance discharge of the battery at low temperatures. The porosity should not be too low.With low porosity, the electrolyte solution has difficulty flowing into the interior of the electrode plate, resulting in uneven wetting. In areas where the electrolyte solution is excessively enriched, lithium precipitation occurs, posing a safety risk. This poses a safety risk because lithium is easily deposited. In areas with insufficient wetting, however, lithium ion migration is hindered, and the gram capacity is abnormal.

[0038] Regarding the positive electrode plate, the adjustment of the roughness of the positive electrode plate and the porosity of the positive electrode plate can be achieved by adjusting the particle size and shape, coating design, particle size distribution, and stacking mode of the positive electrode active material, or by adjusting the coating and rolling conditions of the positive slurry during the preparation of the positive electrode plate, or by adjusting the addition of components such as a binder and a dispersant in the positive electrode active material layer, or by performing surface treatment and filling treatment of the positive electrode plate.

[0039] In addition, the particle size change rate of the positive electrode active material, the roughness of the positive electrode plate, and the porosity of the positive electrode plate also have a special interaction. When the porosity of the positive electrode plate is high, the surface of the positive electrode plate may exhibit a special concave-convex structure, so the roughness of the positive electrode plate increases. The particle size change rate of the positive electrode active material reflects the particle thickness and the proportion of secondary particles of the positive electrode active material. The proportion of secondary particles influences the porosity size and roughness. The particle thickness affects the formation of microcracks, voids, or cavities in the particles of the positive electrode active material and thus also affects the porosity of the positive electrode plate.

[0040] Considering that the particle size change rate of the positive electrode active material, the roughness of the positive electrode plate, and the porosity of the positive electrode plate all affect the low-temperature electrical performance of the battery to a certain extent and influence each other, it is difficult to achieve a battery with high low-temperature capacity retention and high low-temperature discharge performance by controlling a single variable.In the present invention, by rationally controlling the particle size change rate D of the positive electrode active material, the roughness R of the positive electrode plate, and the porosity P of the positive electrode plate, the following relationship is satisfied: 1.2≤D / (R / 5+P / 2)≤3.5, so that the battery including the positive electrode plate has a high capacity retention rate at low temperatures and has good discharge performance at low temperatures and high rates.

[0041] In the present invention, the value of D / (R / 5+P / 2) may be, for example, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.5, 2.8, 3.0, 3.2, 3.4 or 3.5 or an interval between two of the above values.

[0042] In one implementation, the particle size change rate D of the positive electrode active material, the roughness R of the positive electrode plate, and the porosity P of the positive electrode plate satisfy the following relationship: 1.7 ≤ D / (R / 5 + P / 2) ≤ 2.5.

[0043] In one implementation, the particle size change rate D of the positive electrode active material ranges from 60% to 90%. For example, D is 60%, 62%, 65%, 70%, 75%, 80%, 85%, 88%, or 90%.

[0044] In a preferred embodiment, the particle size change rate D of the positive electrode active material is between 65% and 80%.

[0045] Within the above-mentioned range of particle size change rate, the positive electrode active material has appropriate particle thickness and secondary particle content, which can ensure that the positive electrode plate has good structural strength and stability, and at the same time, the positive electrode plate can have appropriate pores and voids, which contributes to improving the high-rate discharge performance and low-temperature capacity retention rate of the battery.

[0046] The present invention is not limited to the method for determining the particle size change rate D, and a person skilled in the art would be able to determine the particle size change rate of the positive electrode active material using conventional technical means. For example, D can be determined using the following method.

[0047] The lithium-ion battery is disassembled to obtain a positive electrode plate. The positive electrode plate is soaked in DMC (dimethyl carbonate) at normal temperature for 60 minutes. It is removed and dried at normal temperature and humidity of ≤ 15%. The positive electrode active material layer is scraped off the surface of the current collector and subjected to calcination at 500°C for 3 hours to remove the conductive agent, binder, surface-side reaction products, and residual electrolyte solution, and the positive electrode active material is obtained after post-treatment.

[0048] The positive electrode active material is dispersed in an aqueous solution containing 3% sodium hexametaphosphate as a dispersant, and this solution is continuously stirred with a glass rod for 10 cycles. All samples are quickly poured into a sample pool for particle size distribution analysis. V 50 test and obtain a Dv50 value before pressure maintenance, which is known as D V 50 vor dem Druck is recorded.

[0049] Then, solid-liquid separation and drying are performed on the mixture containing the positive electrode active material to obtain the positive electrode active material again. The positive electrode active material is kept under a pressure of 35 kN by the powder compactor for 30 seconds. After the pressure is maintained, the positive electrode active material is taken out to undergo another D V50 test in a particle size tester according to the method mentioned above to obtain a D V 50 value after maintaining the pressure, which is known as D V 50 nach dem Druck is recorded.

[0050] The particle size change rate D of the positive electrode active material is obtained by calculation: D=|(Dv50before printing−Dv50after printing)| / Dv50before printing×100%

[0051] In the above calculation, D V 50 is the particle size in µm corresponding to 50% of the cumulative volume distribution percentage of the positive electrode active material.

[0052] The particle size change rate of the positive electrode active material depends on various factors and can be controlled by changing the precursor of the positive electrode active material, the pulverization conditions, and the heat treatment conditions during preparation. It is also possible to obtain a positive electrode active material with a specific particle size change rate by sieving the mass.

[0053] In one implementation, the positive electrode plate has a roughness R in the range of 80 nm to 200 nm. For example, R can be 80 nm, 90 nm, 100 nm, 120 nm, 150 nm, 180 nm, 190 nm, or 200 nm.

[0054] In a preferred embodiment, the positive electrode plate has a roughness R in the range of 100 nm to 150 nm.

[0055] When the roughness is within the above-mentioned preferred range, the positive electrode plate has good contact performance with the electrolyte solution, the battery has high electrochemical reaction efficiency, and the phenomenon of electrode polarization is not aggravated. The battery has a high capacity retention rate at low temperatures and high discharge performance at low temperatures.

[0056] Regarding the method for determining the roughness R, the present invention is not limited, and a person skilled in the art would be able to determine the roughness of the positive electrode plate using conventional technical means. For example, R can be determined by the following method.

[0057] The lithium-ion battery is disassembled to obtain a positive electrode plate. The disassembled positive electrode plate is soaked in a solvent (DMC) to clean the remaining electrolyte solution. The solvent is replaced every 4 hours. The remaining electrolyte solution is continuously cleaned three times. The positive electrode plate is removed and dried to obtain an electrode plate sample.

[0058] A clean and flat 40 mm × 40 mm electrode plate sample is selected and mounted on an atomic force microscope sample stage. The surface of the positive electrode active material layer of the electrode plate sample is contacted with an atomic force microscope probe and automatically scanned. After the test is completed, the roughness of the electrode plate sample is obtained via an "image Ra" value in a "result" of a software test. At least three different locations of the same electrode plate sample are selected for parallel testing, and the average value, namely the roughness of the positive electrode plate, is calculated.

[0059] In one implementation, the positive electrode plate has a porosity P in the range of 15% to 30%. For example, the P can be 15%, 16%, 18%, 20%, 23%, 25%, 28%, 29%, or 30%.

[0060] In a preferred embodiment, the porosity P of the positive electrode plate is in the range of 18% to 25%.

[0061] Within the scope of the present invention, the method for determining porosity P is not limited. A person skilled in the art would have been able to determine the porosity of the positive electrode plate using conventional technical means. For example, P can be determined using the following method.

[0062] The lithium-ion battery is disassembled to obtain a positive electrode plate. The disassembled positive electrode plate is soaked in a solvent (DMC) to clean the remaining electrolyte solution. The solvent is replaced every 4 hours. The remaining electrolyte solution is continuously cleaned three times. The positive electrode plate is removed, dried, and cut into a 12 mm diameter wafer using a punching machine to obtain an electrode plate sample.

[0063] A 12 mm diameter electrode plate sample is weighed. The electrode plate sample is placed in the hexadecane solution and soaked for 1 hour, then removed. After the solution is blotted onto a filter paper surface, the electrode plate sample is weighed again. The rate of change in the mass of the electrode plate sample before and after soaking in hexadecane is calculated, which is the porosity of the positive electrode plate.

[0064] In one implementation, the particle size D V 50 of the positive electrode active material 3 µm to 8 µm.

[0065] In a preferred implementation, the particle size D V 50 of the positive electrode active material in the range of 5 µm to 7.5 µm.

[0066] If the particle size D V50 of the positive electrode active material is within the above-mentioned preferable range, the positive electrode plate has higher capacity performance and energy density at low temperature and better discharge capacity at high rate.

[0067] In one implementation, the ternary positive electrode active material has the formula LiNixCoyMn (1-x-y) O2, where 0.7≤x<1, 0 <y≤0,3, und 0<x+y<1.

[0068] In the context of the present invention, the method for the preparation of LiNi x Co y Mn (1-x-y) O2 is not limited. A person skilled in the art can prepare a positive electrode active material using conventional technical means. For example, the precursor of the positive electrode active material and the lithium source are mixed and subjected to a sintering treatment to obtain a positive electrode active material.

[0069] The precursor of the positive electrode active material may be one or more oxides, hydroxides, and carbonates containing Ni, Co, and Mn in a stoichiometric ratio, for example, hydroxides containing Ni, Co, and Mn in a stoichiometric ratio. The precursor of the positive electrode active material can be obtained by a method known in the art, for example, by a coprecipitation method, a gel method, or a solid-phase method.

[0070] As an example, a Ni source, a Co source, and a Mn source are dispersed in a solvent to obtain a mixed solution. The mixed solution, the strong base solution, and the complexing agent solution are simultaneously pumped into a stirred reaction vessel, with the pH of the reaction solution controlled at 10-13 and the temperature in the reaction vessel at 25-90°C. The mixture is protected by an inert gas during the reaction. After the reaction is complete, aging, filtration, ash removal, and vacuum drying are performed to obtain a hydroxide containing Ni, Co, and Mn.

[0071] In some examples of the invention, the Ni source comprises at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel oxalate, or nickel acetate, and / or the Co source comprises at least one of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt oxalate, or cobalt acetate; and / or the Mn source comprises at least one of manganese sulfate, manganese nitrate, manganese chloride, manganese oxalate, or manganese acetate, and / or the Li source comprises at least one of lithium oxide (Li2O), lithium phosphate (Li3PO4), lithium dihydrogen phosphate (LiH2PO4), lithium acetate (CH3COOLi), lithium hydroxide (LiOH), lithium carbonate (Li2CO3), or lithium nitrate (LiNO3).

[0072] The positive electrode active material precursor and the lithium source can be mixed using a ball mill or a high-speed mixer. The mixed material is introduced into an atmospheric sintering furnace for sintering. The sintering atmosphere is an oxygen-containing atmosphere, such as air or oxygen.

[0073] In addition, the positive electrode active material can also be subjected to a coating process. Specifically, a coating material is applied to the surface of the positive electrode active material by dry coating (high-temperature solid-state method). The surface of the positive electrode active material is partially or completely covered with a coating layer formed by the coating material. The coating layer comprises at least one element (hereinafter referred to as "coating element") selected from the group consisting of aluminum (Al), titanium (Ti), tungsten (W), boron (B), phosphorus (P), cobalt (Co), yttrium (Y), and silicon (Si).

[0074] In addition to the positive electrode active material, the positive electrode active material layer may also comprise a conductive agent and a binder.

[0075] The conductive agent is used to ensure electrical conductivity in the electrode. Any conductive agent can be used without particular restrictions, as long as it has suitable electrical conductivity without causing adverse chemical changes in the battery. This preferably includes carbon fibers such as carbon nanofibers, carbon black such as acetylene black and Ketjen black, and carbon materials such as activated carbon, graphite, mesoporous carbon, fullerenes, and carbon nanotubes.

[0076] The binder improves the adhesion between the particles of the positive electrode active material and the adhesion between the positive electrode active material and the current collector. Suitable binders for use in embodiments are fluoropolyolefin-based binders, which may include, but are not limited to, polyvinylidene fluoride (PVDF), vinylidene fluoride copolymers, or modified (e.g., carboxylic acid, acrylic acid, acrylonitrile, etc.) derivatives thereof, and the like.

[0077] In the present invention, the positive electrode current collector is not particularly limited as long as it is electrically conductive without causing adverse chemical changes in the battery, and the positive electrode current collector includes, for example, stainless steel, aluminum, nickel, titanium, burnt carbon, or aluminum or stainless steel surface-treated with any of carbon, nickel, titanium, silver, etc.

[0078] In the present invention, the positive electrode plate can be prepared by conventional methods known in the art. For example, a positive electrode active material, a conductive agent, and a binder are dispersed in a solvent. The solvent can be N-methylpyrrolidone (NMP) or deionized water to form a uniform positive electrode slurry. The positive electrode slurry is applied to a positive electrode current collector. After drying, rolling, and the like, a positive electrode plate is obtained. Electrochemical device

[0079] According to one example of the present invention, an electrochemical device is provided. The electrochemical device comprises the positive electrode plate as described above, a negative electrode plate or negative pole piece, and an electrolyte solution or electrolyte.

[0080] The negative electrode plate of the present invention comprises a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector. The negative electrode active material layer comprises a negative electrode active material and may also comprise a conductive agent and / or a binder.

[0081] The negative electrode current collector is not particularly limited in the present invention, as long as it has high conductivity without causing adverse chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like, or an aluminum-cadmium alloy can be used.

[0082] Regarding the negative electrode active material, the type of negative electrode active material in the examples of the present invention is not specifically limited and can be selected according to practical requirements. The negative electrode active material may, for example, be one or more of the following materials: natural graphite, artificial graphite, mesophase carbon microspheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, SiOm (0 <m<2, z.B. m=1), Li-Sn-Legierung, Li-Sn-O-Legierung, Sn, SnO, SnO2, spinell-strukturiertes Lithiumtitanat Li4Ti5O 12 , Li-Al alloy and metallic lithium.

[0083] The examples of the present invention do not specifically limit the types of the conductive agent and the binder in the negative electrode active material layer, and they can be selected according to practical requirements. The conductive agent includes, for example, one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The binder includes one or more of styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl butyral, aqueous acrylic resin, and carboxymethyl cellulose. The negative electrode active material layer may optionally also include a thickener such as carboxymethyl cellulose.

[0084] The electrolyte solution of the present invention may be any electrolyte solution suitable in the art for use in electrochemical energy storage devices. The electrolyte solution comprises an electrolyte and a solvent. The electrolyte solution may generally comprise a lithium salt.

[0085] Specifically, the lithium salt comprises at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonimide (LiFSI), lithium bistrifluoromethosulfonimide (LiTFSI), lithium triflate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorooxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5 mol / L to 5 mol / L.

[0086] In some embodiments, the solvent can be selected from at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE). The solvent can be present in an amount of 70 to 98 wt.% based on the weight of the electrolyte solution.

[0087] Furthermore, the electrolyte solution may comprise additives. In particular, the additive may include a membrane-forming additive for the negative electrode or negative electrode plate, and the additive may include a membrane-forming additive for the positive electrode or positive electrode plate. The additive may include an additive capable of improving specific properties of the battery, e.g., an additive for improving the overcharge properties of the battery, an additive for improving the high-temperature properties of the battery, or an additive for improving the low-temperature properties of the battery, etc.

[0088] The electrochemical device may further comprise a separator disposed between the positive electrode plate and the negative electrode plate to separate the positive electrode plate and the negative electrode plate from each other and prevent the positive electrode plate and the negative electrode plate from contacting and causing a short circuit. The separator may be any material known in the art that is suitable as a separator for electrochemical energy storage devices. In particular, the separator comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fiber. Electrical device

[0089] Examples of the present invention provide an electrical device comprising the electrochemical device described above. The electrochemical device serves as a power supply for the electrical device.

[0090] An electric device refers to any device that can use electrical energy and convert it into mechanical energy, heat energy, light energy, etc., such as an electric motor, an electric heat engine, an electric light source, etc. The electric device may include, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, etc. The mobile device may be a mobile phone, a notebook or laptop, an unmanned aerial vehicle or drone, a sweeping robot, an electric cigarette, etc. The electric vehicle may be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, or the like.

[0091] The invention is further illustrated by the following specific examples. Example 1

[0092] This example provides a lithium-ion battery, and the specific preparation method is as follows. (1) Preparation of the positive electrode plate

[0093] Step (1.1): According to the molar ratio of the individual elements Li, Ni, Co and Mn in the chemical formula LiNi 0.9 Co 0.05 Mn 0.05 O2, nickel sulfate, cobalt sulfate, manganese sulfate, and lithium carbonate are each weighed. Lithium carbonate is present in slight excess. The ratio between the molar amount of lithium carbonate and the total molar amount of nickel sulfate, cobalt sulfate, and manganese sulfate (Li / Me) is given in Table 1.

[0094] Step (1.2): Nickel sulfate, cobalt sulfate, and manganese sulfate are each dissolved in deionized water. Each metal solution is transferred to a reaction vessel through a pipe to form a mixed metal solution, with nitrogen introduced as a protective gas. An aqueous NaOH solution is added to the mixed metal solution as a precipitating agent and ammonia as a complexing agent. The ammonia concentration and the addition amount of the solution are adjusted to control the pH of the solution (i.e., the pH of the precursor reaction). After the 10-hour reaction, the product is filtered and dried to obtain a ternary precursor. The pH of the precursor reaction and the drying temperature (i.e., the drying temperature of the precursor) are shown in Table 1.

[0095] Step (1.3): The ternary precursor is mixed with a portion of lithium carbonate (20 wt.% lithium carbonate) to perform pre-sintering. The pre-sintering atmosphere is an oxygen-containing atmosphere (oxygen flow rate 120 m 3 / h). The pre-sintering time is 3 hours, and the pre-sintering temperature is given in Table 1. After cooling, the pre-sintered product is mixed with the remaining lithium carbonate (80 wt% lithium carbonate), and high-temperature sintering is performed. The high-temperature sintering atmosphere is an oxygen-containing atmosphere. The controlled oxygen flow rate, as well as the temperature and time of the high-temperature sintering, are given in Table 1.

[0096] Step (1.4): The sintered material is ground, crushed and sieved to obtain a ternary positive electrode active material.

[0097] Step (1.5): A positive electrode active material, a binder (polyvinylidene fluoride), and a conductive agent (carbon black) are mixed in a mass ratio of 97:1:2. N-methylpyrrolidone (NMP) is added to the mixture and stirred under a vacuum stirrer until the mixed system forms a positive slurry with uniform flowability. The positive slurry is evenly coated on the positive electrode current collector (aluminum foil). The positive electrode current collector coated with the positive slurry is placed in a furnace for drying and then rolled and cut to obtain a positive electrode plate. (2) Preparation of the negative electrode plate

[0098] A negative electrode active material (artificial graphite), a conductive agent (CNT), a thickener (carboxymethylcellulose, CMC), and a binder (styrene-butadiene rubber, SBR) are mixed in a mass ratio of 96:2:1:1. A negative slurry is prepared in a wet process using a vacuum stirrer. The negative slurry is evenly coated on a negative electrode current collector (a copper foil). The negative slurry coated with the negative electrode current collector is placed in a furnace for drying and then rolled and cut to obtain a negative electrode plate. (3) Preparation of the electrolyte solution

[0099] Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a weight ratio of 1:1 to obtain an organic solvent, and then sufficient dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte solution with a concentration of 1 mol / L. (4) Preparation of the separator

[0100] A polyethylene (PE) separator coated with ceramic and polyvinylidene fluoride is used. (5) Preparation of the battery

[0101] The prepared positive electrode plate, separator, and negative electrode plate are wound to form a bare cell without liquid injection. The bare cell is placed in an outer packaging film. The above-mentioned prepared electrolyte solution is injected into the dried bare cell. The cell is vacuum-packed, assembled, molded, sorted, and subjected to other processes to obtain a lithium-ion battery. Examples 2-13 and comparative examples 1-3

[0102] Examples 2 to 13 and Comparative Examples 1 to 3 each provide a lithium-ion battery whose preparation method is similar to that of Example 1, except that in the preparation of the positive electrode plate, the reaction pH of the precursor, the drying temperature of the precursor, Li / Me, the oxygen flow rate for high-temperature sintering, the temperature, and the time are shown in Table 1. Examples 14 and 16

[0103] Examples 14 and 16 each provide a lithium-ion battery whose preparation procedure is similar to that of Example 1, except that: (a) In step (1.1) and step (1.2), the pH of the precursor reaction, the drying temperature of the precursor and Li / Me are given in Table 1. (b) In step (1.3), the ternary precursor is mixed with the total lithium carbonate, presintered, and directly sintered at high temperature. The high-temperature sintering atmosphere is an oxygen-containing atmosphere. The oxygen flow control, as well as the temperature and duration of the high-temperature sintering, are listed in Table 1. Example 15

[0104] Examples 14 and 15 each provide a lithium-ion battery whose preparation procedure is similar to that of Example 1, except that: (a) In step (1.1) and step (1.2), the pH of the precursor reaction, the drying temperature of the precursor and Li / Me are given in Table 1; (b) In step (1.3), the ternary precursor is mixed with a portion of the lithium carbonate (30 wt% lithium carbonate) to perform pre-sintering. The pre-sintering atmosphere is an oxygen-containing atmosphere (the oxygen flow rate is 120 m3 / h). The pre-sintering time is 3 hours. The pre-sintering temperature is given in Table 1. After cooling, the pre-sintered product is mixed with the remaining lithium carbonate (70 wt% lithium carbonate) and subjected to high-temperature sintering. The high-temperature sintering atmosphere is an oxygen-containing atmosphere. The oxygen flow rate control, as well as the temperature and time of the high-temperature sintering, are given in Table 1. Examples 17 and 18

[0105] Examples 17 and 18 each provide a lithium-ion battery whose preparation method is similar to that of Example 1, the details of which are described below.

[0106] Example 17: According to the molar ratio of the individual elements Li, Ni, Co and Mn in the chemical formula LiNi 0,8 Co 0,1 Mn 0,1 Nickel sulfate, cobalt sulfate, manganese sulfate, and lithium carbonate are weighed into the O2 solution. Lithium carbonate is present in slight excess. The pH control of the precursor reaction, the precursor drying temperature, Li / Me, the oxygen flow rate for high-temperature sintering, the temperature, and the time are listed in Table 1.

[0107] Example 18: According to the molar ratio of the individual elements Li, Ni, Co and Mn in the chemical formula LiNi 0,7 Co 0,2 Mn 0,1Nickel sulfate, cobalt sulfate, manganese sulfate, and lithium carbonate are weighed in O2. Lithium carbonate is present in slight excess. The pH of the precursor reaction, the precursor drying temperature, the Li / Me ratio, the oxygen flow rate for high-temperature sintering, the temperature, and the time are shown in Table 1.

[0108] Furthermore, in each of the examples and comparative examples of the present invention, the roughness and porosity of the positive electrode plate are adjusted by controlling the conditions of positive slurry coating and rolling in combination with the use of various positive electrode active materials. Table 1 Precursor reaction pH value Drying temperature of the precursor (°C) Li / Me Temperature before sintering (°C) Oxygen flow (m 3 / h) High temperature sintering temperature (°C) Duration of high-temperature sintering (hours) Example 1 9,7 125 1,2 5 350 200 800 10 Example 2 9,3 130 1,2 420 230 750 8 0 Example 3 10,5 120 1,1 5 330 210 780 8,5 Example 4 10,1 115 1,1 8 300 220 830 12 Example 5 9,4 125 1,1 5 400 160 810 9 Example 6 11,2 130 1,2 3 380 200 820 11 Example 7 11,4 115 1,3 5 350 180 790 12 Example 8 9,5 125 1,1 5 370 150 700 10 Example 9 10,3 115 1,3 2 330 250 850 8 Example 10 9,9 130 1,2 8 320 170 770 9,5 Example 11 9,6 115 1,1 2 380 190 740 9 Example 12 9,7 130 1,1 5 400 210 750 11 Example 13 12,1 115 1,3 350 220 800 10,5 Example 14 11,8 110 1,2 8 / 220 780 12 Example 15 12,3 115 1,1 5 330 230 860 7,5 Example 16 9,4 110 1,1 / 160 700 12,5 Example 17 10,6 130 1,3 1 300 200 830 8,5 Example 18 10,3 120 1,3 7 380 240 840 10 Comparison Example 1 9,9 130 1,1 9 400 200 760 11 Comparison Example 2 11,4 110 1,2 5 420 220 820 8 Comparison Example 3 10,2 150 1,2 350 250 810 12

[0109] For each example and comparative example, the roughness and porosity of the positive electrode plate as well as the D V50 and the particle size change rate of the positive electrode active material were measured as shown in Table 2, and the above measurement methods are as follows: D V 50 and the particle size change rate of the positive electrode active material

[0110] The lithium-ion battery is disassembled to obtain a positive electrode plate. The positive electrode plate is soaked in DMC (dimethyl carbonate) at normal temperature for 60 minutes, removed, and dried at normal temperature with a humidity of ≤ 15%. The positive electrode active material layer is scraped off the surface of the current collector and calcined at 500°C for 3 hours to remove the conductive agent, binder, surface-side reaction products, and residual electrolyte solution, and the positive electrode active material is obtained after post-treatment.

[0111] The positive electrode active material is dispersed in an aqueous solution containing 3% sodium hexametaphosphate as a dispersant, and this solution is continuously stirred with a glass rod for 10 cycles. All samples are quickly poured into a sample pool for a particle size distribution instrument to obtain a D V 50 test and obtain a Dv50 before pressurization, which is known as D V 50 vor dem Druck is recorded, namely the Dv50 of the positive electrode active material.

[0112] Then, solid-liquid separation and drying are performed on the mixture containing the positive electrode active material to obtain the positive electrode active material again. The positive electrode active material is kept under a pressure of 35 kN in a powder compactor for 30 seconds. After the pressure is maintained, the positive electrode active material is removed to undergo another D V50 test in a particle size tester according to the method mentioned above to obtain a D V 50 after maintaining the pressure known as D V 50 nach dem Druck is recorded.

[0113] The particle size change rate D of the positive electrode active material is obtained by calculation: D = |(D V 50 vor dem Druck - D V 50 nach dem Druck )| / D V 50 vor dem Druck × 100%.

[0114] D V 50 is the particle size in µm, which corresponds to 50% of the cumulative volume distribution percentage of the positive electrode active material. Roughness of the positive electrode plate

[0115] The lithium-ion battery is disassembled to obtain a positive electrode plate. The disassembled positive electrode plate is soaked in a solvent (DMC) to clean the remaining electrolyte solution. The solvent is replaced every 4 hours. The remaining electrolyte solution is continuously cleaned three times. The positive electrode plate is removed and dried to obtain an electrode plate sample.

[0116] A clean and flat 40 mm × 40 mm electrode plate sample is selected and mounted on an atomic force microscope sample platform. An atomic force microscope probe touches the surface of the electrode plate sample and performs automatic scanning. After the test is completed, the roughness of the electrode plate sample is obtained via an "Image Ra" value in a "Result" of the test software. At least three different locations of the same electrode plate sample are selected for parallel testing, and the average value is calculated, namely the roughness of the positive electrode plate. Porosity of the positive electrode plate

[0117] The lithium-ion battery is disassembled to obtain a positive electrode plate. The disassembled positive electrode plate is soaked in a solvent (DMC) to clean the remaining electrolyte solution. The solvent is replaced every 4 hours. The remaining electrolyte solution is continuously cleaned three times. The positive electrode plate is removed, dried, and cut into a 12 mm diameter wafer using a sheet metal punch to obtain an electrode plate sample.

[0118] A 12 mm diameter electrode plate sample is weighed. The electrode plate sample is placed in the hexadecane solution and soaked for 1 hour, then removed. After the solution is blotted onto a filter paper surface, the electrode plate sample is weighed again. The rate of change in the mass of the electrode plate sample before and after soaking in hexadecane is calculated, which is the porosity of the positive electrode plate. Table 2 D V 50 (µm) D (%) R (°) P (%) D / (R / 5+P / 2) Example 1 6,5 68,1 114 22,77 1,99 Example 2 6,9 66 135 18,21 1,83 Example 3 5,8 71,5 103 20,35 2,32 Example 4 6,1 77,8 110 19,3 2,46 Example 5 7,2 72,2 147 24,2 1,74 Example 6 4,8 62,8 113 28,5 1,70 Example 7 4,4 83,4 95 33,29 2,34 Example 8 6,8 76,7 174 16,52 1,78 Example 9 5,5 79,6 102 18,74 2,67 Example 10 7,5 65,1 145 24,94 1,57 Example 11 7,7 83 191 33,7 1,51 Example 12 7,3 62,1 172 34,53 1,20 Example 13 4,0 78 83 21 2,88 Example 14 4,1 88,9 86 17,17 3,45 Example 15 4,6 93,6 121 13,3 3,03 Example 16 7,4 86,1 230 39 1,31 Example 17 6,2 63 97 21,1 2,10 Example 18 6,4 60,5 83 18,9 2,32 Comparative Example 1 7,1 61 198 33 1,09 Comparative Example 2 5,1 89,6 81,3 15,2 3,76 Comparative 6,2 46 127 32,1 1,11 Example 3

[0119] The lithium-ion batteries prepared in the examples and comparative examples are subjected to performance tests according to the following projects and methods. (1) Capacity retention rate in -10°C cycle

[0120] The lithium-ion battery is placed in an environment of -10°C and left to stand until the lithium-ion battery reaches a constant temperature. At -10°C, the lithium-ion battery is charged to 4.3V at a constant current of 0.2C, and the lithium-ion battery is charged at a constant voltage of 0.05C. The lithium-ion battery is discharged to 2.75V at 0.33C, and this capacity is taken as the initial capacity C0. This step is repeated for 500 cycles, and the capacity of 500 cycles is recorded as C1. The capacity retention rate for the low-temperature cycle is calculated: Capacity retention rate for the low-temperature cycle = C1 / C0×100%. (2) Discharge power at 5°C

[0121] The lithium-ion battery is placed in an environment of 5°C until the lithium-ion battery reaches a constant temperature. The lithium-ion battery is charged to 4.3V at 5°C with a constant current / constant voltage of 0.33C, set aside for 10 minutes, and discharged to a cutoff voltage of 2.8V at a constant current of 0.33C. The discharge capacity is recorded as C3. The lithium-ion battery is charged to 4.3V at 5°C with a constant current / constant voltage of 0.33C, set aside for 10 minutes, and charged to a cutoff voltage of 2.8V at a constant current of 2C. The discharge capacity is recorded as C4. The capacity maintenance rate for discharge capacity is calculated using the following formula: Capacity maintenance rate for discharge capacity = C4 / C3×100%.

[0122] The test results can be seen in Table 3. Table 3 Capacity retention rate in -10°C cycle (%) 5°C rate discharge power Example 1 95,2% 98,5% Example 2 94,0% 98,0% Example 3 93,7% 98,1% Example 4 93,1% 98,9% Example 5 94,4% 99,1% Example 6 90,8% 96,2% Example 7 91,6% 96,5% Example 8 91,9% 97,8% Example 9 89,0% 94,9% Example 10 88,5% 95,4% Example 11 85,5% 94,2% Example 12 86,2% 93,6% Example 13 86,8% 92,9% Example 14 87,3% 92,5% Example 15 84,6% 91,0% Example 16 83,9% 91,2% Example 17 89,5% 95,3% Example 18 88,1% 95,8% Comparative Example 1 70,3% 84,2% Comparative Example 2 72,7% 82,1% Comparative Example 3 66,8% 84,5%

[0123] For the lithium-ion battery manufactured in each example of the present invention, the capacity retention rate after 500 cycles at -10°C is ≥ 83%, and the capacity retention rate at a 2C rate discharge at 5°C is ≥ 91%. It is found that the lithium-ion battery comprising the positive electrode plate of the present invention has significantly improved electrochemical performance at low temperatures, particularly excellent capacity retention rate at low temperatures and high-rate discharge performance at low temperatures.

[0124] From Examples 6 to 8 in conjunction with Examples 1 to 5 and Examples 11 to 14 in conjunction with Comparative Examples 9 and 10, it is understood that the low-temperature cycling capacity retention rate and high-temperature discharge performance of the lithium-ion battery are relatively better when the particle size change rate of the positive electrode active material, the roughness, and the porosity of the positive electrode plate satisfy the preferable range of the present invention.

[0125] From Examples 9 to 10 in combination with Examples 1 to 5, it can be seen that the capacity retention rate at low temperatures and the discharge performance of the lithium-ion battery at high temperatures are relatively higher when the positive electrode plate satisfies a value of D / (R / 5 + P / 2) of 1.7 to 2.5.

[0126] According to the test results of Comparative Examples 1 to 3, even if the roughness and porosity of the positive electrode plate or the particle size change rate of the positive electrode active material are within appropriate ranges, when the D / (R / 5 + P / 2) value of the positive electrode plate exceeds the range of 1.2 to 3.5, the lithium-ion battery including the positive electrode plate has poor electrochemical performance at low temperatures, with a capacity retention rate at low temperatures of not more than 72.7% and a capacity retention rate at low temperatures during discharge of not more than 84.5%.

Claims

[1] A positive electrode plate comprising a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, characterized by , that the positive electrode active material layer comprises a positive electrode active material comprising a ternary positive electrode active material; a particle size change rate of the positive electrode active material, a roughness of the positive electrode plate, and a porosity of the positive electrode plate satisfy the following relationship: 1.2≤D / (R / 5+P / 2)≤3.5; where D is the particle size change rate of D V 50 in % before and after the positive electrode active material is held at a pressure of 35 KN for 30 seconds, and D V 50 is a particle size corresponding to 50% of a cumulative volume distribution percentage of the positive electrode active material; R is the roughness of the positive electrode plate in nm; and P is the porosity of the positive electrode plate in %. [2] Positive electrode plate according to claim 1, characterized by that the particle size change rate of the positive electrode active material, the roughness of the positive electrode plate and the porosity of the positive electrode plate satisfy the following relationship: 1.7≤D / (R / 5+P / 2)≤2.

5. [3] Positive electrode plate according to one of the preceding claims, characterized by that D is in the range of 60% to 90%. [4] Positive electrode plate according to one of the preceding claims, characterized by that D is in the range of 65% to 80%. [5] Positive electrode plate according to one of the preceding claims, characterized by that R is in the range of 80 nm to 200 nm. [6] Positive electrode plate according to one of the preceding claims, characterized by that R is in the range of 100 nm to 150 nm. [7] Positive electrode plate according to one of the preceding claims, characterized by that P is between 15% and 35%. [8] Positive electrode plate according to one of the preceding claims, characterized by that P is in the range of 18% to 25%. [9] Positive electrode plate according to one of the preceding claims, characterized by that D V 50 is in the range of 3 µm to 8 µm. [10] Positive electrode plate according to one of the preceding claims, characterized by that the ternary positive electrode active material has the formula LiNi x Co y Mn (1-x-y) O2, where 0.7≤x<1, 0 <y≤0,3, und 0<x+y<1. [11] Positive electrode plate according to one of claims 1 to 9, characterized by that the ternary positive electrode active material has the formula LiNi x Co y Mn (1-x-y) O2, where 0.8≤x<1, 0 <y≤0,3, und 0<x+y<1. [12] Positive electrode plate according to one of claims 1 to 9, characterized bythat the ternary positive electrode active material has the formula LiNi x Co y Mn (1-x-y) O2, where 0.9≤x<1, 0 <y≤0,3, und 0<x+y<2. [13] A positive electrode plate according to any one of the preceding claims, wherein the positive electrode current collector comprises stainless steel, aluminum, nickel, titanium, burnt carbon or aluminum. [14] The positive electrode plate according to any one of the preceding claims, wherein the positive electrode active material layer may comprise, in addition to the positive electrode active material, a conductive agent and a binder. [15] A positive electrode plate according to any one of the preceding claims, wherein the conductive agent comprises carbon fibers, carbon black and / or carbon materials [16] A positive electrode plate according to any one of the preceding claims, wherein the binder is a fluoropolyolefin-based binder. [17] Electrochemical device, in particular lithium-ion battery, characterized by that it comprises the positive electrode plate according to one of claims 1 to 14. [18] An electrochemical device according to claim 17, comprising a negative electrode plate and an electrolyte solution or electrolyte. [19] The electrochemical device according to claim 18, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, and wherein the negative electrode active material layer comprises a negative electrode active material. [20] An electrochemical device according to claim 19, wherein copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or an aluminum-cadmium alloy is provided or used for the negative electrode current collector. [21] The electrochemical device according to claim 19 or 20, wherein the negative electrode active material comprises one or more of the following materials: silicon, silicon-carbon composite material and SiOm with 0 <m<2, z.B. m=1. [22] The electrochemical device according to any one of claims 19 to 21, wherein the negative electrode active material comprises one or more of the following materials: Li-Al alloy and metallic lithium. [23] The electrochemical device according to any one of claims 19 to 22, wherein the negative electrode active material comprises one or more of the following materials: natural graphite, artificial graphite, mesophase carbon microspheres (MCMB), hard carbon, soft carbon, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2, and spinel-structured lithium titanate Li4Ti5O 12 . [24] An electrochemical device according to any one of claims 19 to 23, wherein the negative electrode active material comprises a conductive agent. [25] The electrochemical device according to claim 24, wherein the conductive agent of the negative electrode plate comprises one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. [26] An electrochemical device according to any one of claims 19 to 25, wherein the negative electrode active material comprises a binder. [27] The electrochemical device according to claim 26, wherein the binder of the negative electrode plate comprises one or more of styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl butyral, aqueous acrylic resin, and carboxymethyl cellulose. [28] An electrochemical device according to any one of claims 19 to 27, wherein the negative electrode active material layer comprises a thickener, eg carboxymethylcellulose. [29] An electrochemical device according to any one of claims 18 to 28, wherein the electrolyte solution comprises an electrolyte and a solvent. [30] An electrochemical device according to any one of claims 18 to 29, wherein the electrolyte comprises a lithium salt. [31] The electrochemical device according to claim 30, wherein the lithium salt comprises at least one of lithium hexafluorophosphate or LiPF6, lithium tetrafluoroborate or LiBF4, lithium perchlorate or LiClO4, lithium hexafluoroarsenate or LiAsF6, lithium bisfluorosulfonimide or LiFSI, lithium bis-trifluoromethosulfonimide or LiTFSI, lithium triflate or LiTFS, lithium difluorooxalate borate or LiDFOB, lithium dioxalate borate or LiBOB, lithium difluorophosphate or LiPO2F2, lithium difluorooxalate phosphate or LiDFOP and lithium tetrafluorooxalate phosphate or LiTFOP. [32] An electrochemical device according to any one of claims 18 to 31, wherein the concentration of the electrolyte in the electrolyte solution is 0.5 to 5 mol / L. [33] The electrochemical device according to any one of claims 29 to 32, wherein the solvent comprises at least one of ethylene carbonate or EC, propylene carbonate or PC, ethyl methyl carbonate or EMC, diethyl carbonate or DEC, dimethyl carbonate or DMC, dipropyl carbonate or DPC, methyl propyl carbonate or MPC, ethyl propyl carbonate or EPC, butylene carbonate or BC, fluoroethylene carbonate or FEC, methyl formate or MF, methyl acetate or MA, ethyl acetate or EA, propyl acetate or PA, methyl propionate or MP, ethyl propionate or EP, propyl propionate or PP, methyl butyrate or MB, ethyl butyrate or EB, 1,4-butyrolactone or GBL, sulfolane or SF, dimethyl sulfone or MSM, methyl ethyl sulfone or EMS, and diethyl sulfone or ESE. [34] An electrochemical device according to any one of claims 29 to 33, wherein the solvent is contained in an amount of 70 to 98 wt% based on the weight of the electrolyte solution. [35] The electrochemical device according to any one of claims 18 to 34, wherein the electrolyte solution comprises a membrane-forming additive for the negative electrode plate and a membrane-forming additive for the positive electrode plate. [36] An electrochemical device according to any one of claims 18 to 35, comprising a separator between the positive electrode plate and the negative electrode plate. [37] The electrochemical device of claim 36, wherein the separator comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fiber. [38] An electrochemical device according to any one of claims 17 to 37 for use as a power supply for an electrical device, the electrical device comprising: an electric motor, a heat engine, a light source, a vehicle, a train, a ship, a satellite, an energy storage system, a mobile phone, a notebook computer, an unmanned aerial vehicle, a sweeping robot, or an electric cigarette. [39] The electrochemical device of claim 38, wherein the vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck. [40] Electrical device, characterized by that it comprises the electrochemical device according to one of claims 17 to 39. [41] An electrical device according to claim 40, wherein the electrochemical device serves as a power supply for the electrical device. [42] An electrical device according to claim 40, which is configured as an electric motor, heat engine, light source, vehicle, train, ship, satellite, energy storage system, mobile phone, notebook, unmanned aerial vehicle, sweeping robot, or electric cigarette. [43] The electric device of claim 42, wherein the vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck.