Positive electrode plate for lithium ion battery, lithium ion battery including the same, and power utilization device

Abstract

The present application provides a positive electrode plate for a lithium-ion battery, comprising a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector and made of a positive electrode active material mixture comprising the following substances: First positive electrode active material polycrystalline particles having a particle size of 11.0 to 20.0 μm; second positive electrode active material polycrystalline particles having a particle size of 6.0 to 10.5 μm; and The third positive electrode active material single crystal particles having a particle size of 1.1 to 5.2 μm. The present application further provides a lithium ion battery positive plate, in which the number of polycrystalline particles of the first positive active material is a, the number of polycrystalline particles of the second positive active material is b, and the number of single crystalline particles of the third positive active material is c, and (a+b):c is in the range of 5.7:4.3 to 7.7:2.3. The present application further provides a lithium ion battery, a battery module, a battery pack, and a power utilization device, each including the positive plate.

Description

Technical Field

[0001] This application relates to the technical field of lithium batteries, and particularly to a positive electrode plate of a lithium-ion battery, a lithium-ion battery including the same, and a power utilization device.

Background Art

[0002] In recent years, as the application range of lithium-ion batteries has been expanding, lithium-ion batteries have been widely used in multiple fields such as energy storage power systems such as hydraulic, thermal, wind, and solar power plants, and electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. Since lithium-ion batteries have achieved great development, higher requirements have also been put forward for their energy density, processing performance, etc.

[0003] There is still a certain difference between the compact density of the positive electrode active material and the limit compact density of the positive electrode active material in the positive electrode plate of conventional lithium-ion batteries. Simply improving the roll pressure to improve the compact density of the positive electrode plate may cause the elongation rate of the electrode plate to become too large at a high active material loading. With an excessive elongation rate of the electrode plate, problems such as brittle fracture are likely to appear during the winding or hot pressing process of the electrode plate. Therefore, there is still a need to develop a positive electrode plate for a lithium-ion battery with a low elongation rate and a high compact density at a high active material loading.

Summary of the Invention

[0004] This application is made in view of the above problems, and its purpose is to provide a positive electrode plate for a lithium-ion battery that can achieve a high compact density of the electrode plate with a low elongation rate of the electrode plate even at a high active material loading.

[0005] In order to achieve the above object, according to a first aspect of this application, a positive electrode plate of a lithium-ion battery includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector and composed of a positive electrode active material mixture composed of the following substances: The first positive electrode active material polycrystalline particles having a particle diameter of 11.0 to 20.0 μm, The second positive electrode active material polycrystalline particles having a particle diameter of 6.0 to 10.5 μm, and The third positive electrode active material single crystal particles having a particle diameter of 1.1 to 5.2 μm The number of the first positive electrode active material polycrystalline particles is a, the number of the second positive electrode active material polycrystalline particles is b, and the number of the third positive electrode active material single crystal particles is c, and (a + b):c is in the range of 5.7:4.3 to 7.7:2.3, provided is a positive electrode plate of a lithium ion battery.

[0006] Thereby, in the present application, by combining three types of positive electrode active materials having different particle diameters at a specific ratio, the positive electrode plate can obtain a high compact density with a low elongation rate even at a high loading amount of the positive electrode material.

[0007] In any embodiment, (a + b):c is in the range of 6.1:3.9 to 7.2:2.8. By further selecting the ratio of the quantities of the three types of positive electrode active material particles, the compact density of the positive electrode plate can be further improved.

[0008] In any embodiment, the first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles are all ternary positive electrode active materials. Optionally, the chemical compositions of the first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles are the same or different, and all have the chemical formula LiNi a Co b M (1-a-b) O2, and among them, 0.8 ≦ a < 1.0, 0 < b < 0.2, and a + b < 1.0, and M is one or more selected from Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg, Nb. Selecting the positive electrode active material as a ternary material and selecting a specific chemical composition contribute to obtaining a high gram capacity, an initial Coulomb efficiency, and a cycle life of the battery.

[0009] In any embodiment, the pore volume of the positive electrode film layer is 1.2 mm3 / g ~ 4.0 mm 3 It is in the range of / g. By controlling the pore volume of the positive electrode film layer, it is possible to ensure that the positive electrode plate has a high compact density with a low elongation rate.

[0010] In any embodiment, the shear stress of the positive electrode plate is in the range of 0.65 MPa to 0.85 MPa. Such a positive electrode plate can obtain good toughness after the electrode plate is stretched at a high roll pressure and can ensure that it is not easily brittle fractured.

[0011] In any embodiment, in the positive electrode active material mixture, the Dv50 of the first positive electrode active material polycrystalline particles is 12 to 16 μm, and the total mass is A, the Dv50 of the second positive electrode active material polycrystalline particles is 8 to 10 μm, and the total mass is B, the Dv50 of the third positive electrode active material single crystal particles is 2.5 to 4 μm, and the total mass is C, and (A + B):C is in the range of 6:4 to 8:2, and optionally, in the range of 6.5:3.5 to 7.5:2.5. By controlling the mass ratio of these three types of positive electrode active material particles, it is possible to ensure that the positive electrode plate has a high compact density with a low elongation rate.

[0012] In any embodiment, the compact density CPD-1T of the positive electrode active material mixture at a pressure of 1 ton is 3.0 g / cm 3 ~ 3.2 g / cm 3 is in the range of. By controlling the compact density of the positive electrode active material mixture at a pressure of 1 ton to be in the above range, it is possible to ensure that the positive electrode plate has a high compact density with a low elongation rate.

[0013] In any embodiment, the BET specific surface area of the positive electrode active material mixture is 0.5 m 2 / g ~ 0.7 m 2 / g is in the range of. By controlling the BET specific surface area of the positive electrode active material mixture to be in the above range, it is possible to ensure that the positive electrode plate has a high compact density with a low elongation rate.

[0014] In any embodiment, the SPAN value of the positive electrode active material mixture is in the range of 1.70 to 2.20, and in particular, SPAN = (Dv90 - Dv10) / Dv50. By controlling the SPAN value of the positive electrode active material mixture to be within the above range, it is possible to ensure that the positive electrode plate has a high compact density with a low elongation rate.

[0015] In any embodiment, the Dv99 of the positive electrode active material mixture is in the range of 18 μm to 21 μm. By controlling the Dv99 of the positive electrode active material mixture to be within the above range, the compact density of the positive electrode plate can be improved.

[0016] In any embodiment, the SPAN value of the first positive electrode active material polycrystalline particles satisfies SPAN ≤ 1.20, and optionally, 0.50 ≤ SPAN ≤ 1.00. By controlling the SPAN value of the first positive electrode active material polycrystalline particles to be within the above range, sufficient filling space can be provided, and high gram capacity can be exhibited in the positive electrode plate.

[0017] In any embodiment, the SPAN value of the second positive electrode active material polycrystalline particles satisfies SPAN ≥ 1.20, and optionally, 1.30 ≤ SPAN ≤ 1.50. By controlling the SPAN value of the second positive electrode active material polycrystalline particles to be within the above range, the gaps and spaces can be sufficiently filled, and the compact density of the positive electrode plate can be improved.

[0018] In any embodiment, the SPAN value of the third positive electrode active material single crystal particles satisfies SPAN ≤ 1.70, and optionally, 1.10 ≤ SPAN ≤ 1.40. By controlling the SPAN value of the third positive electrode active material single crystal particles to be within the above range, high pressure resistance can be provided to the positive electrode plate.

[0019] In any embodiment, the tap density of the third positive electrode active material single crystal particles is TPD ≤ 1.8 g / cm 3 and optionally, 1.2 g / cm 3 ≤ TPD ≤ 1.5 g / cm 3It is so. When the tap density of the third positive electrode active material single crystal particles is within the above range, by having a highly dispersible form, the space utilization rate of the positive electrode plate can be further improved, and the compact density of the electrode plate can be improved.

[0020] According to a second aspect of the present application, there is further provided a lithium ion battery including the positive electrode plate of the first aspect of the present application.

[0021] According to a third aspect of the present application, there is provided a battery module including the lithium ion battery of the second aspect of the present application.

[0022] According to a fourth aspect of the present application, there is provided a battery pack including the battery module of the third aspect of the present application.

[0023] According to a fifth aspect of the present application, there is provided a power utilization device including at least one selected from the lithium ion battery of the second aspect of the present application, the battery module of the third aspect of the present application, or the battery pack of the fourth aspect of the present application.

Brief Description of the Drawings

[0024]

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Modes for Carrying Out the Invention

[0025] Hereinafter, with appropriate reference to the drawings, embodiments of the positive electrode plate of the lithium-ion battery of the present application, the lithium-ion battery, battery module, battery pack, and power utilization device including the same will be described in detail and specifically disclosed. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of actually similar structures may be omitted. This is to avoid making the following description unnecessarily long and to enable those skilled in the art to easily understand. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the gist described in the claims.

[0026] The "range" disclosed in the present application is limited in the form of a lower limit and an upper limit. A predetermined range is limited by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundary of a special range. The range limited in this way may or may not include extreme values and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, when ranges of 60 to 120 and 80 to 110 are given for a specific parameter, it is also expected to be understood as ranges of 60 to 110 and 80 to 120. Also, when minimum range values of 1 and 2 are given, and maximum range values of 3, 4, and 5 are given, the following ranges: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all predictable. In the present application, unless otherwise specified, the numerical range "a~b" indicates an abbreviated representation of any combination of real numbers from a to b, and in particular, both a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers from "0~5" are listed in this specification, but "0~5" is only an abbreviated representation of the combination of these numerical values. Also, when it is indicated that a certain parameter is an integer of 2 or more, it is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] Unless otherwise specified, all embodiments and selectable embodiments of the present application can be combined with each other to form new technical means.

[0028] Unless otherwise specified, all technical features of the present application and selectable technical features can be combined with each other to form new technical means.

[0029] Unless otherwise specified, all steps of the present application may be performed in order, may be performed randomly, and it is preferable to perform them in order. For example, when it is said that the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed in order, or may include steps (b) and (a) performed in order. For example, when it is said that the above-described method may further include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), may include steps (a), (c), and (b), may include steps (c), (a), and (b), etc.

[0030] Unless otherwise specified, the terms "comprising" and "including" referred to in the present application indicate an open type and may also be a closed type. For example, the "comprising" and "including" mean that other components not listed may be further included or included, or only the listed components may be included or included.

[0031] Unless otherwise specified, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions also satisfies the condition "A or B". A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0032] In order to achieve high cell mass and volumetric energy density, on the one hand, the gram capacity of the positive electrode active material can be improved, and on the other hand, the compact density at a high loading amount of the active material of the positive electrode plate can be improved. However, if the compact density of the positive electrode plate is improved simply by increasing the roll pressure, phenomena such as pulverization of the positive electrode active material particles and slippage of the particles are likely to occur, so the positive electrode plate exhibits a large longitudinal elongation rate, for example, 0.8% or more. With an excessive elongation rate of the electrode plate, problems such as brittle fracture are likely to occur during the winding or hot pressing process. Therefore, there is still a need to develop a positive electrode plate for a lithium-ion battery with a high loading amount of active material, a low elongation rate, and a high compact density.

[0033] It has been discovered by the inventors of the present application that when a positive electrode active material is formed by mixing positive electrode active material polycrystalline particles in two specific particle size ranges and positive electrode active material single crystal particles in one specific particle size range at a specific ratio, the obtained positive electrode plate can achieve a low elongation rate and a high compact density.

[0034] The "single crystal" and "polycrystalline" described in the present application have the meanings commonly used in the technical field of positive electrode active materials. Generally, positive electrode active material polycrystalline particles are spherical aggregates formed by the deposition of a plurality of small crystal particles, and positive electrode active material single crystal particles are monomeric or similar aggregates in which small crystal particles with clear boundaries are alone or deposited in several. The "single crystal" and "polycrystalline" can be confirmed by observing the morphology of the particles by a method well-known in the art, for example, a scanning electron microscope.

[0035] In one embodiment of the present application, the present application provides a positive electrode plate for a lithium-ion battery, including a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector and composed of a positive electrode active material mixture composed of the following substances: First positive electrode active material polycrystalline particles with a particle size of 11.0 - 20.0 μm, Second positive electrode active material polycrystalline particles with a particle size of 6.0 - 10.5 μm, and Third positive electrode active material single crystal particles with a particle size of 1.1 - 5.2 μm The number of the first positive electrode active material polycrystalline particles is a, the number of the second positive electrode active material polycrystalline particles is b, the number of the third positive electrode active material single crystal particles is c, and (a + b):c is in the range of 5.7:4.3 to 7.7:2.3, and a positive electrode plate of a lithium ion battery is provided.

[0036] In the present application, the particle diameter of a particle means the distance between the two farthest points in the particle in a photograph taken by a scanning electron microscope (SEM). The particle diameter of a particle can be measured by equipment and methods well-known in the art. For example, a scanning electron microscope photograph of a positive electrode plate is obtained by using a scanning electron microscope (for example, ZEISS Sigma 300) with reference to JY / T010-1996.

[0037] In the present application, the number of one type of particle is obtained by randomly selecting 10 regions on a positive electrode plate, taking an SEM photograph for each region, summing up the number of the particles corresponding to the particle diameter range in each measurement region from the SEM photograph, and calculating the average value of the number of the particles in each measurement region.

[0038] Although the mechanism is not clear, the applicant has surprisingly found that by combining two types of polycrystalline cathode active materials with different particle sizes and one type of single-crystalline cathode active material in a specific ratio, the gaps between particles and the volume utilization rate can be sufficiently improved, and the pressure resistance of the cathode plate can be improved. Therefore, even with a high loading amount of the cathode active material, the cathode plate can obtain a high compact density with a low elongation rate. Although it is not desired to be limited to theory, currently, the first polycrystalline cathode active material particles with a particle size of 11.0 - 20.0 μm serve as the skeleton of the cathode film layer. If the particle size is too large, the edges of the particles are likely to crack, and at the same time, the gram capacity is restricted. If the particle size is too small, it is considered that they do not have the function of the skeleton. The second polycrystalline cathode active material particles with a particle size of 6.0 - 10.5 μm serve as the primary filler, improving the space utilization rate and the performance of the gram capacity. The third single-crystalline cathode active material particles with a particle size of 1.1 - 5.2 μm serve as the secondary filler. Due to their high dispersibility and pressure resistance, they can sufficiently fill the gaps left by the first polycrystalline cathode active material particles and the second polycrystalline cathode active material particles. And by setting the quantitative ratio (a + b):c of the three to be in the range of 5.7:4.3 - 7.7:2.3, the gram capacity and the compact density can be maximally balanced. In such a dense deposition, displacement / slippage of particles at high pressure is less likely to occur, preventing the electrode plate from having a large elongation and improving brittleness. If the above ratio is too small, it will affect the capacity of the battery. If it is too large, it is difficult to play a role in improving the compact density.

[0039] In some embodiments, (a + b):c is in the range of 6.1:3.9 - 7.2:2.8, for example, 6.2:3.8. By further selecting the quantitative ratio of the three types of cathode active material particles, the compact density of the cathode plate can be further improved.

[0040] The ratio of the number a of the first polycrystalline cathode active material particles to the number b of the second polycrystalline cathode active material particles may be arbitrarily selected according to the actual requirements of those skilled in the art. For example, a:b may be in the range of 1:9 - 7.5:2.5.

[0041] The first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles can have the chemical composition of a normal positive electrode active material in this field. As an example, the positive electrode active material may include at least one of materials such as lithium-containing phosphates having an olivine structure, lithium transition metal oxides, and modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery may be further used. These positive electrode active materials may be used alone, or two or more of them may be used in combination. Among them, examples of lithium transition metal oxides include lithium cobalt oxide (for example, LiCoO2), lithium nickel oxide (for example, LiNiO2), lithium manganese oxide (for example, LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which may be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which may be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which may be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which may be abbreviated as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which may be abbreviated as NCM 811 ), lithium nickel cobalt aluminum oxide (for example, LiNi 0.85 Co 0.15 Al 0.05It may include, but is not limited to, at least one of O2) and its modified compounds. Examples of lithium-containing phosphates with an olivine structure include lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and at least one of a composite material of lithium manganese iron phosphate and carbon, but is not limited thereto.

[0042] In some embodiments, the first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles are all ternary positive electrode active materials. Optionally, the chemical compositions of the first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles are the same or different, and all have the chemical formula LiNi a Co b M (1-a-b) O2, and among them, 0.8 ≦ a < 1.0, 0 < b < 0.2, and a + b < 1.0, and M is one or more selected from Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg, Nb. Selecting the positive electrode active material as a ternary material and selecting a specific chemical composition contribute to obtaining high gram capacity, initial Coulomb efficiency, and the cycle life of the battery.

[0043] In some embodiments, the pore volume of the positive electrode film layer is in the range of 1.2 mm 3 / g to 4.0 mm 3 / g, and optionally, in the range of 1.2 mm 3 / g to 2.0 mm 3 / g. By controlling the pore volume of the positive electrode film layer, it can be ensured that the positive electrode plate has a high compact density with a low elongation rate.

[0044] Pore volume has the meaning well-known in the art. In the present application, the pore volume of the positive electrode film layer can be measured using methods well-known in the art. As an example, reference can be made to Part 2: Analysis of Mesopores and Macropores by Gas Adsorption of GB / T 21650.2-2008 / ISO 15901-2:2006 "Measurement of Pore Size Distribution and Void Ratio of Solid Materials by Mercury Intrusion Method and Gas Adsorption Method", and it can be measured using the AccuPyc II 1340 true density meter of the equipment.

[0045] In some embodiments, the shear stress of the positive electrode plate is in the range of 0.65 MPa to 0.85 MPa. With such a large tensile strength of the positive electrode plate, it is possible to ensure good toughness after the electrode plate is stretched at a high roll pressure and is not easily brittlely fractured.

[0046] Shear stress has the meaning well-known in the art. In the present application, the shear stress is measured by the following method. A sample with a width of 0.02 m, a length of 0.1 m, and an exposed current collector region for welding tabs at the edge was cut from the electrode plate to be measured. A double-sided adhesive tape with a width of 0.02 m and a length of 0.09 m, with one end aligned with one end of the steel plate, was attached to a steel plate with a width of 0.02 m and a length of 0.2 m. The sample of the electrode plate was attached to the double-sided adhesive tape, and one end of the sample was aligned with one end of the double-sided adhesive tape. A paper tape with a width of 0.02 m and a length of 0.15 m was fixed to the exposed current collector surface of the sample of the electrode plate. The end of the steel plate where the electrode plate was not attached was fixed with the lower jig of the tensile machine, the paper tape was folded back upwards and fixed with the upper jig, the tensile machine was turned on, and continuous tension of 180° was performed at a tensile speed of 0.05 m / min. When the fracture of the electrode plate was recorded, the maximum load indicated by the tensile machine was recorded as the shear stress of the electrode plate.

[0047] In some embodiments, in the positive electrode active material mixture, the Dv50 of the first positive electrode active material polycrystalline particles is 12 to 16 μm, for example, 12 to 13 μm, 13 to 16 μm, and the total mass is A; the Dv50 of the second positive electrode active material polycrystalline particles is 8 to 10 μm, for example, 8 to 9 μm, 9 to 10 μm, and the total mass is B; the Dv50 of the third positive electrode active material single crystal particles is 2.5 to 4 μm, for example, 2.5 to 3 μm, 3 to 4 μm, and the total mass is C; (A + B):C is in the range of 6:4 to 8:2, and optionally, in the range of 6.5:3.5 to 7.5:2.5. By controlling the mass ratio of these three types of positive electrode active material particles, it can be ensured that the positive electrode plate has a high compact density with a low elongation rate.

[0048] The ratio of the total mass A of the first positive electrode active material polycrystalline particles to the total mass B of the second positive electrode active material polycrystalline particles may be arbitrarily selected according to the actual requirements of those skilled in the art. For example, A:B may be in the range of 2:8 to 7:3.

[0049] In the present application, the volume distribution particle size Dv50 of the positive electrode active material particles, and Dv10, Dv90, and Dv99 mentioned below are well-known concepts in this field. Specifically, Dv10 is the particle size at which the volume integration becomes 10% from the small particle size side in the particle size distribution based on the volume of the particles. Dv50 is the particle size at which the volume integration becomes 50% from the small particle size side in the particle size distribution based on the volume of the particles. Dv90 is the particle size at which the volume integration becomes 90% from the small particle size side in the particle size distribution based on the volume of the particles. Dv99 is the particle size at which the volume integration becomes 99% from the small particle size side in the particle size distribution based on the volume of the particles. As the measurement method for the particle volume distribution particle sizes Dv10, Dv50, Dv90, and Dv99, methods well-known in this field can be used. As an example, with reference to the GB / T 19077-2016 / ISO 13320:2009 laser diffraction method for particle size distribution, it can be measured using the Malvern Mastersizer3000 equipment.

[0050] In some embodiments, the compacted density CPD-1T of the positive electrode active material mixture at a pressure of 1 ton is 3.0 g / cm 3 ~3.2 g / cm 3 and, optionally, is in the range of 3.1 g / cm 3 ~3.2 g / cm 3 . By controlling the compacted density of the positive electrode active material mixture at a pressure of 1 ton to be within the above range, it is possible to ensure that the positive electrode plate has a high compacted density with a low elongation rate.

[0051] In the present application, as a method for measuring the compacted density CPD-1T (Compacted Density) of the positive electrode active material mixture at a pressure of 1 ton, a method well-known in the art can be used. As an example, referring to GB / T 5162-2006 "Graphite Negative Electrode Materials for Lithium-Ion Batteries", it can be measured using the UTM7305 electronic pressure tester of the equipment.

[0052] In some embodiments, the BET specific surface area of the positive electrode active material mixture is 0.5 m 2 / g to 0.7 m 2 / g, and, optionally, is in the range of 0.59 m 2 / g to 0.63 m 2 / g. By controlling the BET specific surface area of the positive electrode active material mixture to be within the above range, it is possible to ensure that the positive electrode plate has a high compacted density with a low elongation rate.

[0053] In the present application, as a method for measuring the BET specific surface area of the positive electrode active material mixture, a method well-known in the art can be used. As an example, referring to GB / T 19587-2017 "Measurement of Specific Surface Area of Solids by Gas Adsorption BET Method", it can be measured using the TriStar II 3020 of the equipment.

[0054] In some embodiments, the SPAN value of the positive electrode active material mixture is in the range of 1.70 to 2.20, and among them, SPAN = (Dv90 - Dv10) / Dv50. Optionally, the SPAN value of the positive electrode active material mixture is in the range of 1.75 to 2.10. By controlling the SPAN value of the positive electrode active material mixture to be within the above range, it can be ensured that the positive electrode plate has a high compact density with a low elongation rate.

[0055] In some embodiments, the Dv99 of the positive electrode active material mixture is in the range of 18 μm to 21 μm, and optionally, in the range of 19.5 μm to 21 μm. By controlling the Dv99 of the positive electrode active material mixture to be within the above range, the compact density of the positive electrode plate can be improved.

[0056] In some embodiments, the SPAN value of the first positive electrode active material polycrystalline particles satisfies SPAN ≤ 1.20, and optionally, 0.50 ≤ SPAN ≤ 1.00. By controlling the SPAN value of the first positive electrode active material polycrystalline particles to be within the above range, sufficient filling space can be provided, and high gram capacity can be exhibited in the positive electrode plate.

[0057] In some embodiments, the SPAN value of the second positive electrode active material polycrystalline particles satisfies SPAN ≥ 1.20, and optionally, 1.30 ≤ SPAN ≤ 1.50. By controlling the SPAN value of the second positive electrode active material polycrystalline particles to be within the above range, the gaps and spaces can be sufficiently filled, and the compact density of the positive electrode plate can be improved.

[0058] In some embodiments, the SPAN value of the third positive electrode active material single crystal particles satisfies SPAN ≤ 1.70, and optionally, 1.10 ≤ SPAN ≤ 1.40. By controlling the SPAN value of the third positive electrode active material single crystal particles to be within the above range, high pressure resistance can be provided to the positive electrode plate, and the compact density of the positive electrode plate can be improved.

[0059] In some embodiments, the tap density of the third positive electrode active material single crystal particles satisfies TPD ≦ 1.8 g / cm 3 and, optionally, 1.2 g / cm 3 ≦ TPD ≦ 1.5 g / cm 3 When the tap density of the third positive electrode active material single crystal particles is within the above range, by having a highly dispersible form, the space utilization rate of the positive electrode plate can be further improved, and the compact density of the electrode plate can be improved.

[0060] In the present application, as a method for measuring the tap density TPD (Tap Density) of the positive electrode active material particles, a method well-known in the art can be used. As an example, referring to GB / T 24533-2009 "Measurement of Tap Density of Metal Powders", it can be measured using a Dandong Bettersize BT-300 type tap density meter for equipment.

[0061] Further, with appropriate reference to the drawings below, the lithium ion battery, battery module, battery pack, and power utilization device of the present application will be described.

[0062] In one embodiment of the present application, a lithium ion battery is provided.

[0063] Normally, a lithium ion battery includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During the charge and discharge process of the battery, active ions are repeatedly inserted and desorbed between the positive electrode plate and the negative electrode plate. The electrolyte serves to conduct ions between the positive electrode tab and the negative electrode tab. The separator is provided between the positive electrode plate and the negative electrode plate, mainly serving to prevent short circuit between the positive and negative electrodes and allowing ions to pass through.

[0064] [Positive Electrode Plate] As defined above, the positive electrode plate includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector.

[0065] As an example, the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is provided on either one or both of the two opposing surfaces of the positive electrode current collector.

[0066] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0067] In some embodiments, the positive electrode film layer may optionally further include an adhesive. As an example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0068] In some embodiments, the positive electrode film layer may optionally further include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0069] In some embodiments, the positive electrode plate can be manufactured by the following method. Components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry. The positive electrode slurry is applied to the positive current collector, and after processes such as drying and cold pressing, a positive electrode plate is obtained.

[0070] [Negative electrode plate] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector and containing a negative electrode active material.

[0071] As an example, the negative electrode current collector has two surfaces facing each other in its own thickness direction, and the negative electrode film layer is provided on either one or both of the two opposing surfaces of the negative electrode current collector.

[0072] In some embodiments, the negative electrode current collector may use a metal foil or a composite current collector. For example, as the metal foil, a copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base (such as a base of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0073] In some embodiments, the negative electrode active material may use a negative electrode active material known in the art and used in batteries. As an example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be at least one selected from elemental silicon, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may be at least one selected from elemental tin, tin oxygen compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may be further used. These negative electrode active materials may be used alone or in combination of two or more.

[0074] In some embodiments, the negative electrode film layer may optionally further contain an adhesive. The adhesive may be at least one selected from styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl cellulose (CMCS).

[0075] In some embodiments, the negative electrode film layer may optionally further contain a conductive agent. The conductive agent may be at least one selected from superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0076] In some embodiments, the negative electrode film layer may optionally further contain other auxiliaries, such as a thickening agent (e.g., sodium carboxymethyl cellulose (CMC-Na)) and the like.

[0077] In some embodiments, the negative electrode plate can be manufactured by the following method. Components for manufacturing the negative electrode plate, such as a negative electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (e.g., ion-exchanged water) to form a negative electrode slurry. The negative electrode slurry is applied to a negative electrode current collector, and after processes such as drying and cold pressing, a negative electrode plate is obtained.

[0078] [Electrolyte] The electrolyte serves to conduct ions between the positive electrode plate and the negative electrode plate. The present application has no specific restrictions on the type of electrolyte, and it may be selected as needed. For example, the electrolyte may be in a liquid state, a gel state, or an all-solid state.

[0079] In some embodiments, the electrolyte uses an electrolytic solution. The electrolytic solution contains an electrolyte salt and a solvent.

[0080] In some embodiments, the electrolyte salt may be at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, lithium bisoxalatedifluorophosphate, and lithium tetrafluoro(oxalate)phosphate.

[0081] In some embodiments, the solvent may be at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, ethylene carbonate fluoride, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0082] In some embodiments, the electrolyte may optionally further contain an additive. For example, the additive may include a negative electrode film-forming additive and a positive electrode film-forming additive, and may further include an additive that can improve certain performance of the battery, such as an additive that improves the overcharge performance of the battery, an additive that improves the high-temperature or low-temperature performance of the battery, etc.

[0083] [Separator] In some embodiments, the lithium-ion battery further includes a separator. The present application has no particular limitation on the type of the separator, and any well-known separator having a porous structure with good chemical stability and mechanical stability can be selectively used.

[0084] In some embodiments, the material of the separator may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer thin film or a multi-layer composite thin film, without particular limitation. When the separator is a multi-layer composite thin film, the materials of each layer may be the same or different, without particular limitation.

[0085] In some embodiments, the positive electrode plate, the negative electrode plate, and the separator can be used to manufacture an electrode assembly by a winding process or a lamination process.

[0086] In some embodiments, the lithium-ion battery may include an external package. The external package is used to hermetically package the above electrode assembly and electrolyte.

[0087] In some embodiments, the external package of the lithium-ion battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc. The external package of the lithium-ion battery may be a soft package material, such as a pouch-type soft package material. The material of the pouch may be plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0088] The present application has no particular limitation on the shape of the lithium-ion battery, and it may be cylindrical, rectangular, or any other arbitrary shape. For example, FIG. 2 shows a rectangular-structured lithium-ion battery 5 as an example.

[0089] In some embodiments, referring to FIG. 3, the external package may include a case 51 and a cover plate 53. Among them, the case 51 may include a base plate and side plates connected to the base plate, and the base plate and the side plates surround to form a receiving cavity. The case 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be covered and installed in the opening so as to close the receiving cavity. The positive electrode plate, the negative electrode plate and the separator can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is hermetically packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the lithium-ion battery 5 may be one or more, and those skilled in the art can select according to specific actual requirements.

[0090] In some embodiments, the lithium-ion battery may be assembled as a battery module, and the number of lithium-ion batteries included in the battery module may be one or more. Specifically, those skilled in the art can select according to the application and capacity of the battery module.

[0091] FIG. 4 shows a battery module 4 as an example. Referring to FIG. 4, in the battery module 4, a plurality of lithium-ion batteries 5 may be arranged in sequence in the longitudinal direction of the battery module 4. Of course, they may be arranged according to any other method. Furthermore, the plurality of lithium-ion batteries 5 can be fixed by fastening members.

[0092] Optionally, the battery module 4 may further include a housing having a receiving space, and a plurality of lithium-ion batteries 5 are received in the receiving space.

[0093] In some embodiments, the above battery module may be further assembled as a battery pack, and the number of battery modules included in the battery pack may be one or more. Specifically, those skilled in the art can select according to the application and capacity of the battery pack.

[0094] FIG. 5 and FIG. 6 show a battery pack 1 as an example. Referring to FIGS. 5 and 6, the battery pack 1 may include a battery housing and a plurality of battery modules 4 provided in the battery housing. The battery housing includes an upper housing 2 and a lower housing 3, and the upper housing 2 is covered and installed on the lower housing 3, and it is possible to form a closed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery housing according to any method.

[0095] In addition, in the present application, a power utilization device including at least one of the lithium ion battery, battery module, or battery pack provided by the present application is further provided. The lithium ion battery, battery module, or battery pack may be used as a power source of the power utilization device, or may be used as an energy storage unit of the power utilization device. The power utilization device may include, but is not limited to, mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as battery electric vehicles, hybrid vehicles, plug-in hybrid vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), trains, ships, and satellites, energy storage systems, etc.

[0096] As the power utilization device, a lithium ion battery, battery module, or battery pack can be selected according to the requirements of its use.

[0097] FIG. 7 shows a power utilization device as an example. The power utilization device is a battery electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, or the like. In order to meet the requirements for high power and high energy density of the lithium ion battery of the power utilization device, a battery pack or a battery module may be used.

[0098] Another example of the device may be a mobile phone, a tablet PC, a notebook computer, or the like. The device is usually required to be thinner and lighter, and a lithium ion battery may be used as a power source.

Example

[0099] Examples of the present application will be described below. The examples described below are exemplary and are merely for explaining the present application and should not be construed as limiting the present application. When specific technologies or conditions are not specified in the examples, the technologies or conditions described in the literature in this field are followed, or the product specifications are followed. When the manufacturer of the reagents or instruments used is not specified, they are all general products that can be obtained by purchasing from the market.

[0100] Example 1 The first positive electrode active material polycrystalline particles with a Dv50 of 13 μm, the second positive electrode active material polycrystalline particles with a Dv50 of 9 μm, and the third positive electrode active material single crystal particles with a Dv50 of 3 μm were sequentially charged into a 5 L stirring tank at a ratio where the masses A, B, and C of the three were (A + B):C = 7:3 and A:B was 2.5:7.7. After mixing for 10 min, sampling was performed and the SPAN value, Dv99, CPD-1T, and BET specific surface area of the mixture were measured. All three types of positive electrode active material particles used have the chemical formula LiNi 0.92 Co 0.06 Mn 0.02 O2.

[0101] Thereafter, acetylene black (SP) as a conductive agent and polyvinylidene fluoride (PVDF) as an adhesive were added and pre-mixed for 30 min. Finally, N-methylpyrrolidone (NMP) was added as a solvent, and stirring was quickly performed under vacuum evacuation conditions to form a slurry. Among them, the mass ratio of the positive electrode active material mixture: acetylene black: polyvinylidene fluoride = 96:2:2, and the solid content of the slurry was 70 wt%. The slurry was uniformly coated on both sides of an aluminum foil with a thickness of 12 μm, and the coated electrode plate was taken out after drying in an oven at 100 - 130 °C for half an hour. Among them, the loading amount of the positive electrode active material of the electrode plate was 21.5 mg / cm 2 . After the taken-out positive electrode plate was cold-pressed through the rolls, data on the compact density, elongation rate in the longitudinal direction, pore volume, and shear stress were measured.

[0102] Figure 1 shows a scanning electron microscope image of the positive electrode plate of Example 1. From the drawing, it can be clearly seen that there are three types of positive electrode active material particles with different sizes, and the small particles sufficiently fill the gaps between the large particles.

[0103] Comparative Example 1 The first positive electrode active material polycrystalline particles with a Dv50 of 11 μm, the second positive electrode active material polycrystalline particles with a Dv50 of 6.5 μm, and the third positive electrode active material single crystal particles with a Dv50 of 4.5 μm were sequentially put into a 5 L stirring tank at a ratio where the masses A, B, and C of the three were (A + B):C = 3:7. After mixing for 10 min, sampling was carried out, and the SPAN value, Dv99, CPD - 1T, and BET specific surface area of the mixture were measured. All three types of positive electrode active material particles used have the chemical formula LiNi 0.92 Co 0.06 Mn 0.02 O2.

[0104] After that, acetylene black (SP) as a conductive agent and polyvinylidene fluoride (PVDF) as an adhesive were added and pre - mixed for 30 min. Finally, N - methylpyrrolidone (NMP) was added as a solvent, and stirring was carried out rapidly under vacuum evacuation conditions to form a slurry. Among them, the mass ratio of the positive electrode active material mixture: acetylene black: polyvinylidene fluoride = 96:2:2, and the solid content of the slurry was 70 wt%. The slurry was uniformly coated on both sides of an aluminum foil with a thickness of 12 μm, and the coated electrode plate was taken out after drying in an oven at 100 - 130 °C for half an hour. Among them, the loading amount of the positive electrode active material of the electrode plate was 21.5 mg / cm 2 . After the taken - out positive electrode plate was cold - pressed through the rolls, data on the compact density and elongation rate in the longitudinal direction were measured.

[0105] Examples 2 - 12 and Comparative Examples 2 - 4 As shown in Table 1, the sizes and usage amounts of the first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles were changed respectively, and the positive electrode plates were manufactured and measured in the same manner as in Example 1.

[0106] Measurement method: 1. Particle size and quantity of the positive electrode active material particles Ten regions were randomly selected on the positive electrode plate, and scanning electron microscope photographs of each region were obtained using a scanning electron microscope ZEISS Sigma 300 with reference to JY / T010 - 1996. In the scanning electron microscope (SEM) photograph, the distance between the two farthest points on the particle was measured as the particle size.

[0107] Based on the particle size, it was determined which positive electrode active material particles the particles in the SEM photograph belonged to. From the SEM photograph, the number of various particles in each measurement region was summed up, the average value of the number of these particles in each measurement region was calculated as the number of the positive electrode active material particles, and the ratio (a + b):c was calculated.

[0108] 2. Compact density The compact density CPD of the positive electrode plate was calculated by the formula CPD = M / (d×A). In the formula, M is the mass of a small disk with a diameter of 40 mm cut out from the positive electrode plate, and the average value was taken by weighing 10 times. d is the thickness of the positive electrode plate, and the average value was taken by measuring the thickness 10 times. A is the area of the small disk with a diameter of 40 mm.

[0109] 3. Elongation rate in the longitudinal direction The elongation rate in the longitudinal direction of the electrode plate after cold pressing was calculated by the formula ΔEL%=(L2 - L1) / L1×100%. In the formula, L1 is the distance between the marks before cold pressing, which is 1000 mm, and L2 is the distance between the marks after cold pressing. The marks were formed as follows. In the central region of the electrode plate, at different positions in the width direction of the electrode plate, three line segments with a length of 1000 mm extending in the longitudinal direction of the electrode plate were taken respectively, and marks were made at the two endpoints of the mark line segments. L2 was recorded as the average value of the measured values of the distances between the two endpoints of each line segment after cold pressing.

[0110] 4. Pore volume With reference to Part 2: Analysis of Mesopores and Macropores by Gas Adsorption of "Determination of Pore Size Distribution and Porosity of Solid Materials by Mercury Intrusion Porosimetry and Gas Adsorption Method" (GB / T 21650.2-2008 / ISO 15901-2:2006), the measurement was carried out using the AccuPyc II 1340 True Density Meter of the equipment.

[0111] 5. Shearing stress A sample with a width of 0.02 m, a length of 0.1 m, and an exposed current collector region for welding tabs at the edge was cut from the measured electrode plate. A double-sided adhesive tape with a width of 0.02 m and a length of 0.09 m, with one end aligned with one end of the steel plate, was attached to a steel plate with a width of 0.02 m and a length of 0.2 m. The sample of the electrode plate was attached to the double-sided adhesive tape, and one end of the sample was aligned with one end of the double-sided adhesive tape. A paper tape with a width of 0.02 m and a length of 0.15 m was fixed to the exposed current collector surface of the sample of the electrode plate. The non-attached end of the steel plate with the electrode plate was fixed with the lower fixture of the tensile machine, the paper tape was folded upwards and fixed with the upper fixture, the tensile machine was turned on, and continuous tension of 180° was carried out at a tensile speed of 0.05 m / min. When the fracture of the electrode plate was recorded, the maximum load shown on the tensile machine was recorded as the shearing stress of the electrode plate.

[0112] 6. Particle volume distribution particle sizes Dv10, Dv50, Dv90, Dv99 With reference to "Particle Size Analysis - Laser Diffraction Method" (GB / T 19077-2016 / ISO 13320:2009), the measurement was carried out using the Malvern Mastersizer 3000 of the equipment.

[0113] 7. CPD-1T With reference to "Graphite Anode Materials for Lithium-Ion Batteries" (GB / T 5162-2006), the measurement was carried out using the UTM7305 Electronic Pressure Testing Machine of the equipment.

[0114] 8. BET specific surface area With reference to "Determination of Specific Surface Area of Solids by Gas Adsorption BET Method" (GB / T 19587-2017), the measurement was carried out using the TriStar II 3020 of the equipment.

[0115] 9. TPD With reference to GB / T 24533-2009 "Measurement of Tap Density of Metal Powders", the measurement was carried out using a Dandong Bettersize BT-300 type tap density meter for the equipment.

[0116] The measurement results of the parameters of Examples 1 to 12 and Comparative Examples 1 to 4 are shown in Table 1 below.

Table 1

[0117] From the above results, it was found that Examples 1 to 12 all achieved a high compact density with an elongation rate in the longitudinal direction of the electrode plate lower than 0.8%, and the compact density can exceed approximately 3.6 g / cm 3 .

[0118] In contrast, Comparative Example 2 used only two types of positive electrode active material particles and obtained a compact density of 3.62 g / cm 3 , but the elongation rate in the longitudinal direction of the electrode plate was as high as 0.85%. Comparative Examples 1, 3, and 4 also used a mixture of two types of polycrystalline particles with a large particle size and one type of single crystal particle with a small particle size. However, since the Dv50 values of each particle were not all within the scope of the present application, the elongation rate in the longitudinal direction of the electrode plate when obtaining a high compact density was all higher than 0.8%. Even when the numerical values of (A + B):C in Comparative Examples 3 and 4 were within the scope of the present application, it was impossible to achieve a compact density higher than 3.6 g / cm 3 with an elongation rate in the longitudinal direction of the electrode plate lower than 0.8%.

[0119] It should be noted that the present application is not limited to the above embodiments. The above embodiments are merely examples, and embodiments having a configuration substantially the same as the technical idea and exhibiting the same operational effects within the scope of the technical means of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the gist of the present application, various modifications conceivable by those skilled in the art can be added to the embodiments, and other methods of constructing by combining some components in the embodiments are also included in the scope of the present application.

Explanation of Reference Numerals

[0120] 1 Battery pack 2 Upper housing 3 Lower housing 4 Battery module 5 Lithium-ion battery 51 Case 52 Electrode assembly 53 Top cover assembly

Claims

1. A positive electrode plate for a lithium-ion battery, comprising a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector and composed of a positive electrode active material mixture composed of the following substances: First positive electrode active material polycrystalline particles having a particle diameter of 11.0 to 20.0 μm, Second positive electrode active material polycrystalline particles having a particle diameter of 6.0 to 10.5 μm, and Third positive electrode active material single crystal particles having a particle diameter of 1.1 to 5.2 μm The number of the first positive electrode active material polycrystalline particles is a, the number of the second positive electrode active material polycrystalline particles is b, and the number of the third positive electrode active material single crystal particles is c. (a + b): c is in the range of 5.7:4.3 to 7.7:2.

3. In the positive electrode active material mixture, the Dv50 of the first positive electrode active material polycrystalline particles is 12 to 16 μm, and the total mass is A. The Dv50 of the second positive electrode active material polycrystalline particles is 8 to 10 μm, and the total mass is B. The Dv50 of the third positive electrode active material single crystal particles is 2.5 to 4 μm, and the total mass is C. (A + B): C is in the range of 6:4 to 8:

2. A positive electrode plate for a lithium-ion battery, characterized by the above.

2. (a + b): c is in the range of 6.1:3.9 to 7.2:2.

8. The positive electrode plate according to Claim 1, characterized by the above.

3. The first positive electrode active material polycrystalline particles, the second positive electrode active material polycrystalline particles, and the third positive electrode active material single crystal particles are all ternary positive electrode active materials. The positive electrode plate according to Claim 1, characterized by the above.

4. The pore volume of the positive electrode film layer is 1.2 mm ３ / g to 4.0 mm ３ / g, and is in the range of The positive electrode plate according to Claim 1, characterized by the above.

5. The shear stress is in the range of 0.65 MPa to 0.85 MPa. The positive electrode plate according to Claim 1, characterized by the above.

6. The compact density CPD-1T of the positive electrode active material mixture at a pressure of 1 ton is 3.0 g / cm ３ to 3.2 g / cm ３ and is in the range of The positive electrode plate according to Claim 1, characterized by the above.

7. The BET specific surface area of the positive electrode active material mixture is in the range of 0.5 m ２ / g to 0.7 m ２ / g, The positive electrode plate according to Claim 1, characterized by the above.

8. The SPAN value of the positive electrode active material mixture is in the range of 1.70 to 2.

20. Among them, SPAN = (Dv90 - Dv10) / Dv50. The positive electrode plate according to Claim 1, characterized by the above.

9. The Dv99 of the positive electrode active material mixture is in the range of 18 μm to 21 μm. The positive electrode plate according to Claim 1, characterized by the above.

10. The SPAN value of the first positive electrode active material polycrystalline particles satisfies SPAN ≤ 1.

20. The positive electrode plate according to Claim 1, characterized by the above.

11. The SPAN value of the second positive electrode active material polycrystalline particles satisfies SPAN ≥ 1.

20. The positive electrode plate according to claim 1, characterized in that...

12. The SPAN value of the third positive electrode active material single crystal particles satisfies SPAN ≤ 1.

70. The positive electrode plate according to claim 1, characterized in that...

13. The tap density of the third positive electrode active material single crystal particles is TPD ≤ 1.8 g / cm3. The positive electrode plate according to claim 1, characterized in that...

14. A lithium ion battery comprising the positive electrode plate according to claim 1. Characterized in that...

15. A battery module comprising the lithium ion battery according to claim 14. Characterized in that...

16. A battery pack comprising the battery module according to claim 15. Characterized in that...

17. Comprising at least one selected from the lithium ion battery according to claim 14, the battery module according to claim 15, or the battery pack according to claim 16. Characterized in that...

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