Method for manufacturing positive electrode paste, positive electrode sheet, secondary battery, battery module, battery pack, and power consumption device

Abstract

The present application provides a method for manufacturing a positive electrode paste, a positive electrode sheet, a secondary battery, a battery module, a battery pack, and an electric power consuming device. The manufacturing method includes a first stirring, a second stirring, a third stirring, and a fourth stirring. In the first stirring, a positive electrode active material, a conductive agent, and a first binder are mixed and stirred to produce a dry mixture. In the second stirring, a second binder and a solvent are mixed and stirred to produce an adhesive. In the third stirring, the dry mixture and the adhesive are mixed and stirred to produce a primary paste. In the fourth stirring, a solvent and the primary paste are mixed and stirred to produce a positive electrode paste. The weight average molecular weight of the polymer in the second binder is smaller than the weight average molecular weight of any polymer in the first binder.

Description

Technical Field

[0001] The present invention relates to the technical field of secondary batteries, and in particular, to a method for manufacturing a positive electrode paste, a positive electrode sheet, a secondary battery, a battery module, a battery pack, and an electric power consumption device.

Background Art

[0002] In recent years, with the increasingly expanding application range of secondary batteries, secondary batteries have been widely applied in multiple fields such as energy storage power systems such as hydraulic power, thermal power, wind power, and solar power plants, and further electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc.

[0003] The electrode paste is the basis for forming the electrode and is also the first process in the manufacture of secondary batteries. The characteristics of the electrode paste have a great influence on the subsequent manufacture of the electrode and the performance of the battery. The positive electrode paste is mainly a solid-liquid phase mixing system formed by a positive electrode active material, a conductive agent, a binder, and a solvent. This system is in a metastable state, and the paste mixing process, that is, the method for manufacturing the paste, has a significant impact on the characteristics such as the dispersibility, uniformity, and stability of the paste. The paste mixing process in the prior art is generally a one-step method, in which each component in the positive electrode active material paste is directly mixed and stirred to obtain it, but the manufactured paste has a high viscosity at the time of shipment, and abnormal phenomena such as gelation and precipitation are likely to occur, which affects the subsequent coating, rolling processes, and the quality of the polar sheet.

Summary of the Invention

[0004] The present application has been made in view of the above problems, and its purpose is to provide a method for manufacturing a positive electrode paste for a secondary battery for reducing the viscosity of the positive electrode paste at the time of shipment, expanding the process window of the coating of the positive electrode paste, and improving the processability of the positive electrode paste.

[0005] According to a first aspect of the present application, there is provided a method for manufacturing a positive electrode paste including a first stirring, a second stirring, a third stirring, and a fourth stirring.

[0006] In the first stirring, a positive electrode active material, a conductive agent, and a first binder are mixed and stirred to produce a dry mixture.

[0007] In the second stirring, a second binder and a solvent are mixed and stirred to produce an adhesive.

[0008] In the third stirring, the dry mixture and the adhesive are mixed and stirred to produce a primary paste.

[0009] In the fourth stirring, a solvent and the primary paste are mixed and stirred to produce a positive electrode paste.

[0010] The weight average molecular weight of the polymer in the second binder is smaller than the weight average molecular weight of any polymer in the first binder.

[0011] By using the present application to gradually combine a second binder with a relatively low molecular weight and a first binder with a relatively high molecular weight, the viscosity at the time of shipment of the positive electrode paste is reduced, the processability of the positive electrode paste is improved, and the method has wide versatility and can be applied to the production of pastes containing a new generation of high molecular weight polymer binders.

[0012] The positive electrode paste produced by the production method disclosed in the present application can effectively exhibit the characteristics of polyvinylidene fluoride binders with different molecular weights, and has appropriate viscosity and excellent processability due to the interaction and steric hindrance between long-chain and short-chain segments.

[0013] In any embodiment, the second binder is polyvinylidene fluoride having a weight average molecular weight of 4 million or less.

[0014] By controlling the second binder to polyvinylidene fluoride with a weight average molecular weight of 4 million or less, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved.

[0015] In any embodiment, the second binder is polyvinylidene fluoride with a weight average molecular weight of 2 million or less.

[0016] By making the second binder polyvinylidene fluoride with a weight average molecular weight of 2 million or less, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be significantly reduced, the gelation of the positive electrode paste can be alleviated to a considerable extent, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved.

[0017] In any embodiment, the second binder is polyvinylidene fluoride with a weight average molecular weight of 1.5 million or less.

[0018] By making the second binder polyvinylidene fluoride with a weight average molecular weight of 1.5 million or less, it is advantageous for further reducing the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours, significantly alleviating the gelation of the positive electrode paste, and improving the filtration performance of the positive electrode paste.

[0019] In any embodiment, the first binder includes polyvinylidene fluoride with one or more weight average molecular weights, and the first binder includes polyvinylidene fluoride with a weight average molecular weight of 2 million or more.

[0020] In any embodiment, the first binder includes polyvinylidene fluoride with a weight average molecular weight of 4 million or more.

[0021] The manufacturing method disclosed in the present application has versatility with respect to a polyvinylidene fluoride binder having a low weight average molecular weight and a polyvinylidene fluoride binder having a high weight average molecular weight, enabling the positive electrode paste containing a binder with a weight average molecular weight of up to 8 million to still have an appropriate viscosity, and the polar sheet manufactured from the positive electrode paste to have excellent adhesiveness, capable of meeting the usage requirements of a new generation of binders.

[0022] In any embodiment, with respect to the total mass of the first binder and the second binder, the mass content of the second binder is 30% - 50%.

[0023] By controlling the mass content of the second binder to 30% - 50% with respect to the total mass of the first binder and the second binder, not only can the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours be effectively reduced, the gelation of the positive electrode paste be alleviated, the filtration performance of the positive electrode paste be improved, and the adhesiveness of the positive electrode sheet be enhanced, but it is also advantageous for reducing the manufacturing cost.

[0024] In any embodiment, the revolution speed of the first stirring is 10 rpm - 20 rpm.

[0025] By controlling the revolution speed of the first stirring to 10 rpm - 20 rpm, not only can the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours be effectively reduced, the filtration performance of the positive electrode paste be improved, and the adhesiveness of the positive electrode sheet be enhanced, but it is also advantageous for reducing the manufacturing cost.

[0026] In any embodiment, the stirring time of the first stirring is 10 minutes - 25 minutes.

[0027] By controlling the stirring time of the first stirring to 10 minutes - 25 minutes, not only can the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours be effectively reduced, the gelation of the positive electrode paste be alleviated, the filtration performance of the positive electrode paste be improved, and the adhesiveness of the positive electrode sheet be enhanced, but it is also advantageous for improving the manufacturing efficiency and reducing the manufacturing cost.

[0028] In any embodiment, the revolution speed of the second stirring is 20 rpm to 30 rpm.

[0029] By controlling the revolution speed of the second stirring to 20 rpm to 30 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be improved. Moreover, it is also advantageous for reducing the manufacturing cost.

[0030] In any embodiment, the rotation speed of the second stirring is 1000 rpm to 1400 rpm.

[0031] By controlling the rotation speed of the second stirring to 1000 rpm to 1400 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be improved. Moreover, it is also advantageous for reducing the manufacturing cost.

[0032] In any embodiment, the stirring time of the second stirring is 60 minutes to 90 minutes.

[0033] By controlling the stirring time of the second stirring to 60 minutes to 90 minutes, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be improved. Moreover, it is also advantageous for improving the manufacturing efficiency and reducing the manufacturing cost.

[0034] In any embodiment, the stirring time of the third stirring is 60 minutes to 90 minutes, the revolution speed is 20 rpm to 30 rpm, and the rotation speed is 500 rpm to 800 rpm.

[0035] In the third stirring, by adding the dry mixture produced in the first stirring to the adhesive produced in the second stirring and stirring slowly, the risk that the high molecular weight polymer in the first binder aggregates and gels is reduced, and the uniformity of kneading between materials is improved.

[0036] In any embodiment, the revolution speed of the fourth stirring is 20 rpm to 30 rpm, the rotation speed is 1000 rpm to 1400 rpm, and the stirring time is 90 minutes to 120 minutes.

[0037] In the fourth stirring, by quickly stirring at a high stirring rotation speed, sufficient mixing and dispersion of the materials are realized, so that the paste meets the processability and electrical characteristics of the lithium-ion battery.

[0038] In any embodiment, the solid content of the positive electrode paste is 63% to 73%, and the initial viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s.

[0039] The paste formed by the manufacturing method of the present application has a high solid content, an appropriate viscosity, and excellent processability. The above paste can be directly used in the subsequent coating process, and the manufacturing efficiency can be improved.

[0040] In any embodiment, the solvent used in the second stirring and the solvent used in the fourth stirring are the same. With respect to the total mass of the conductive agent, the positive electrode active material, the first binder, and the second binder, the mass content of the solvent used in the second stirring is 35% to 40%, and the mass content of the solvent used in the fourth stirring is 5% to 10%.

[0041] In any embodiment, in the positive electrode paste, the mass ratio of the positive electrode active material, the total mass of the first binder and the second binder, and the conductive agent is (82 to 95):(3 to 10):(2 to 8).

[0042] The positive electrode paste within the above range not only has good processability, but also the electrical and chemical properties of the formed positive electrode sheet are excellent.

[0043] In any embodiment, the positive electrode active material is one or more of lithium iron phosphate, lithium cobalt oxide, and lithium manganate.

[0044] In any embodiment, the conductive agent is one or more of conductive carbon black, graphite, and carbon nanotubes.

[0045] According to the second aspect of the present application, a positive electrode paste manufactured by the manufacturing method of the positive electrode paste of the first aspect is further provided.

[0046] In any embodiment, the viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s, and the viscosity of the positive electrode paste after standing for 24 hours does not exceed 48000 mPa·s.

[0047] The positive electrode paste provided by the present application has an appropriate viscosity, excellent stability, and good processability.

[0048] According to the third aspect of the present application, a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector are provided, and the positive electrode film layer is manufactured from a positive electrode sheet manufactured from the positive electrode paste manufactured by the manufacturing method according to the first aspect. The positive electrode sheet is excellent in uniformity and adhesion.

[0049] In any embodiment, the adhesion per unit length between the positive electrode film layer and the positive electrode current collector is greater than 20 N / m. The positive electrode sheet has a high adhesion strength between the positive electrode film layer and the positive electrode current collector, and during use, the positive electrode film layer is not easily peeled off from the positive electrode current collector, which is advantageous for improving the cycle characteristics and safety of the battery.

[0050] According to a fourth aspect of the present application, there is further provided a secondary battery including a positive electrode sheet, a separator, a negative electrode sheet, and an electrolytic solution, wherein the positive electrode sheet is produced from a positive electrode paste produced by the production method according to the first aspect or a positive electrode paste according to the second aspect.

[0051] In any embodiment, the secondary battery is any one of a lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, and a potassium-ion battery.

[0052] According to a fifth aspect of the present application, there is further provided a battery module including the secondary battery according to the fourth aspect of the present application.

[0053] According to a sixth aspect of the present application, there is provided a battery pack including the secondary battery according to the fourth aspect of the present application or the battery module according to the fifth aspect of the present application.

[0054] According to a seventh aspect of the present application, there is provided a power consumption device including at least one selected from the secondary battery according to the fourth aspect of the present application, the battery module according to the fifth aspect of the present application, or the battery pack according to the sixth aspect of the present application.

Brief Description of the Drawings

[0055]

Figure 1

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Figure 6

Embodiments for Carrying Out the Invention

[0056] Hereinafter, embodiments specifically disclosing the binder, manufacturing method, electrode, battery, and power consumption device of the present application will be described in detail with reference to the drawings as appropriate. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or duplicate descriptions of substantially the same structures may be omitted. This is to prevent the following descriptions from becoming unnecessarily redundant and to facilitate the understanding of those skilled in the art. Also, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0057] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a specific range. A range defined in this way may or may not include the values at both ends and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, ranges of 60 to 110 and 80 to 120 are also understood to be contemplated. Also, if the minimum range values 1 and 2 are listed, and the maximum range values 3, 4, and 5 are listed, ranges of 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. In the present application, unless otherwise stated, the numerical range "a to b" means an abbreviated expression of any combination of real numbers between a and b, and both a and b are real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" are all listed in this specification, and "0 to 5" is only an abbreviated expression of combinations of these numerical values. Also, when a certain parameter is expressed as an integer ≧2, it corresponds to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0058] All embodiments and selectable embodiments of the present application can be combined with each other to form new technical solutions unless otherwise specified.

[0059] All technical features of this application and selectable technical features can, unless otherwise specified, be combined with each other to form new technical solutions.

[0060] All steps of this application can, unless otherwise specified, be carried out in sequence or randomly, preferably in sequence. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) carried out in sequence, or steps (b) and (a) carried out in sequence. For example, if it is said that the 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), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0061] As used in this application, "comprising" and "including" indicate both open and closed forms, unless otherwise specified. For example, the "comprising" and "including" can indicate that other components not listed may also be included or included, or can indicate that only the listed components are included or included.

[0062] In this application, unless otherwise specified, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by either A being true (or existing) and B being false (or not existing), or A being false (or not existing) and B being true (or existing), or both A and B being true (or existing).

[0063] The positive electrode paste is a solid-liquid mixed system mainly formed by a positive electrode active material, a conductive agent, a binder, and a solvent. In order to improve the uniformity of the distribution of different components in the system, generally, paste mixing is performed by processes such as stirring, ball milling, and ultrasonic waves. However, the paste mixing process in the prior art is generally only applicable to a paste system with fixed components, lacking versatility. When the physical properties of each component in the paste change, it is often necessary to adjust the paste mixing process. For example, the paste mixing process in the prior art cannot be applied to high molecular weight binders. However, as a result of extensive research, the applicant has discovered that high molecular weight binders can effectively reduce the amount of binder used in the polar sheet and help improve the loading amount of the polar sheet. However, the paste containing the high molecular weight binder has a high viscosity at the time of shipment and is prone to gelation, making it difficult to meet the manufacturing requirements of the polar sheet.

[0064] [Positive electrode paste] Based on this, the present application provides a method for manufacturing a positive electrode paste including a first stirring, a second stirring, a third stirring, and a fourth stirring. In the first stirring, a positive electrode active material, a conductive agent, and a first binder are mixed and stirred to produce a dry mixture. In the second stirring, a second binder and a solvent are mixed and stirred to produce an adhesive. In the third stirring, the dry mixture and the adhesive are mixed and stirred to produce a primary paste. In the fourth stirring, a solvent and the primary paste are mixed and stirred to produce a positive electrode paste. The weight average molecular weight of the polymer in the second binder is smaller than the weight average molecular weight of any polymer in the first binder.

[0065] In some embodiments, the positive electrode active material is one or more of lithium iron phosphate, lithium cobalt oxide, and lithium manganate.

[0066] In some embodiments, the conductive agent includes one or more of conductive carbon black, graphite, and carbon nanotubes.

[0067] In some embodiments, the solvent is an aqueous medium such as deionized water. In some embodiments, the solvent is an oily medium selected from one or more of N-methyl-pyrrolidone, N,N-dimethylpropionamide, N,N-diethylpropionamide, N,N-dipropylpropionamide, N,N-dibutylpropionamide, N,N-dimethylethylpropionamide, and 3-butoxy-N-methylpropionamide.

[0068] In this manufacturing method, first, a cathode active material, a conductive agent, and a first binder with a relatively high molecular weight are first stirred to obtain a dry mixture. Through the first stirring, the three are mechanically bonded to form a tight entanglement. Next, a second binder and a solvent are mixed and the second stirring is performed to produce an adhesive. Moreover, the weight average molecular weight of the polymer in the second binder is smaller than the weight average molecular weight of any polymer in the binder. The adhesive with a relatively low viscosity is then advantageous for dispersing the dry mixture containing the polymer with a large molecular weight into the adhesive. Further, the dry mixture produced by the first stirring and the adhesive are mixed and the third stirring is performed to produce a primary paste. Through the third stirring, the cathode active material and the conductive agent can be effectively dispersed in the adhesive. The binder in the adhesive can improve the stability of the paste through electrostatic action and steric hindrance action, and reduce the aggregation and sedimentation of the cathode active material and the conductive agent. Finally, the solvent and the primary paste are mixed and the fourth stirring is performed to obtain a cathode paste. In the fourth stirring, the viscosity of the paste at the time of shipment can be effectively adjusted by the added solvent again, preventing the viscosity at the time of shipment from being too high and affecting the subsequent coating operation.

[0069] This application reduces the viscosity of the cathode paste at the time of shipment, improves the processability of the cathode paste, by mixing a second binder with a low molecular weight and a first binder with a relatively high molecular weight step by step. Moreover, this method has broad versatility and can be applied to the manufacture of pastes containing a new generation of high molecular weight polymer binders.

[0070] In any embodiment, the second binder is polyvinylidene fluoride having a weight average molecular weight of 4 million or less.

[0071] By controlling the second binder to polyvinylidene fluoride having a weight average molecular weight of 4 million or less, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be enhanced.

[0072] In some embodiments, the weight average molecular weight of polyvinylidene fluoride in the second binder may be selected from any one of 100,000, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,100,000, 1,200,000, 1,300,000, 1,400,000, 1,500,000, 1,600,000, 1,700,000, 1,800,000, 1,900,000, 2,000,000, 2,500,000, 3,000,000, 3,500,000, and 4,000,000.

[0073] As used herein, the term "weight average molecular weight" refers to the statistical average molecular weight based on the mass of the polymer averaged over unit weight. In the present application, the weight average molecular weight of the polymer can be measured using methods known in the art. As an example, measurement is performed using gel chromatography such as Waters 2695 Isocratic HPLC gel chromatograph (differential refractive index detector 2141). A polystyrene solution sample with a mass fraction of 3.0% is used as a reference, and a suitable chromatographic column (oil-based: Styragel HT5DMF7.8×300mm + Styragel HT4) is selected. A 3.0% polymer solution is prepared using a purified N-methylpyrrolidone (NMP) solvent, and the prepared solution is allowed to stand for one day for later use. During measurement, first, tetrahydrofuran is aspirated with a syringe, washed, and this is repeated several times. Next, 5 ml of the test solution is aspirated, the air in the syringe is removed, and the needle tip is wiped and dried. Finally, the sample solution is slowly injected into the injection port. After the display stabilizes, data is acquired and the weight average molecular weight is read.

[0074] In any embodiment, the second binder is polyvinylidene fluoride having a weight average molecular weight of 2 million or less.

[0075] By controlling the second binder to polyvinylidene fluoride having a weight average molecular weight of 2 million or less, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be further reduced, the gelation of the positive electrode paste can be considerably alleviated, and the filtration performance of the positive electrode paste can be improved.

[0076] In any embodiment, the second binder is polyvinylidene fluoride having a weight average molecular weight of 1.5 million or less.

[0077] By controlling the second binder to polyvinylidene fluoride having a weight average molecular weight of 1.5 million or less, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be further reduced, the gelation of the positive electrode paste can be significantly alleviated, and the filtration performance of the positive electrode paste can be improved.

[0078] In any embodiment, the first binder includes polyvinylidene fluoride having one or more weight average molecular weights, and the first binder includes polyvinylidene fluoride having a weight average molecular weight of 2 million or more. In some embodiments, the first binder includes polyvinylidene fluoride having one weight average molecular weight, and the weight average molecular weight thereof is 2 million or more. In some embodiments, the first binder includes polyvinylidene fluoride having two or more different weight average molecular weights, and the weight average molecular weight of at least one of the polyvinylidene fluorides is 2 million or more. In some embodiments, the first binder includes polyvinylidene fluoride having a weight average molecular weight of 4 million or more.

[0079] The weight average molecular weight of the polyvinylidene fluoride having a weight average molecular weight of 2 million or more may be selected from any one or more of 2 million, 2.5 million, 3 million, 3.5 million, 4 million, 4.5 million, 5 million, 5.5 million, 6 million, 6.5 million, 7 million, 7.5 million, 8 million, 8.5 million, 9 million.

[0080] The manufacturing methods of the cathode paste in the prior art have low compatibility, cannot meet the manufacturing requirements of binders with different molecular weights, and it is also impossible to perform high-quality paste mixing of the new generation of high molecular weight polymer binders. The manufacturing method disclosed in the present application is versatile, suitable for binders with different weight average molecular weights, and can particularly meet the manufacturing requirements of the new generation of high molecular weight polymer binders, effectively reducing the viscosity of the cathode paste at the time of shipment and after standing for 24 hours, and helping to improve the coating property and processability of the cathode paste.

[0081] In some embodiments, with respect to the total mass of the first binder and the second binder, the mass content of the second binder is 30% to 50%. In some embodiments, the mass content of the second binder may be selected from any one of 30%, 32%, 34%, 35%, 36%, 38%, 40%, 42%, 44%, 45%, 46%, 48%, 50%.

[0082] By controlling the mass content of the second binder to 30% to 50% with respect to the total mass of the first binder and the second binder, the high adhesion performance of the high molecular weight polymer in the first binder can be fully exerted, not only improving the adhesion of the cathode sheet, but also guaranteeing the processability of the cathode paste, especially ensuring that the viscosity at the time of shipment and the viscosity after standing for 24 hours are low, and having excellent gelation prevention characteristics and filterability.

[0083] In some embodiments, the rotation speed of the first stirring is 0. In some embodiments, the revolution speed of the first stirring is 10 rpm to 20 rpm. In some embodiments, the revolution speed of the first stirring may be selected from any one of 10 rpm, 11 rpm, 12 rpm, 13 rpm, 14 rpm, 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm.

[0084] In this specification, the term "rotation speed" refers to the speed at which the stirrer rotates around its own axis.

[0085] In this specification, the term "revolution speed" refers to the speed at which the agitator rotates around the tank filled with the material.

[0086] In some embodiments, the stirring device is a planetary mixer. The operating principle of the planetary mixer is that when the mixer is started, the planetary carrier rotates, rotationally drives the stirring shaft in the box, rotates at high speed while revolving around the axis of the barrel, so that the material is subjected to strong shearing and kneading actions. It should be noted that the manufacturing method provided in this application is suitable for all types of planetary mixers.

[0087] By controlling the rotation speed of the first stirring to 0, damage to the material in the dry mixing process can be reduced. By controlling the revolution speed of the first stirring to 10 rpm to 20 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be improved. Moreover, it is also advantageous for reducing the manufacturing cost.

[0088] In some embodiments, the stirring time of the first stirring is 10 minutes to 25 minutes. In some embodiments, the stirring time of the first stirring can be selected from any one of 10 minutes, 12 minutes, 14 minutes, 15 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, and 25 minutes.

[0089] By controlling the stirring time of the first stirring to 10 minutes to 25 minutes, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesion of the positive electrode sheet can be improved. Moreover, it is also advantageous for improving the manufacturing efficiency and reducing the manufacturing cost.

[0090] In some embodiments, the revolution speed of the second stirring is 20 rpm to 30 rpm. In some embodiments, the revolution speed of the second stirring may be selected from any one of 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm, and 30 rpm.

[0091] By controlling the revolution speed of the second stirring to be 20 rpm to 30 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. Moreover, it is also advantageous for reducing the manufacturing cost.

[0092] In some embodiments, the rotation speed of the second stirring is 1000 rpm to 1400 rpm. In some embodiments, the rotation speed of the second stirring may be selected from any one of 1000 rpm, 1050 rpm, 1100 rpm, 1150 rpm, 1200 rpm, 1250 rpm, 1300 rpm, 1350 rpm, or 1400 rpm.

[0093] By controlling the rotation speed of the second stirring to be 1000 rpm to 1400 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. Moreover, it is also advantageous for reducing the manufacturing cost.

[0094] In some embodiments, the stirring time of the second stirring is 60 minutes to 90 minutes. In some embodiments, the stirring time of the second stirring may be selected from any one of 60 minutes, 62 minutes, 65 minutes, 68 minutes, 70 minutes, 73 minutes, 75 minutes, 77 minutes, 80 minutes, 85 minutes, and 90 minutes.

[0095] By controlling the stirring time of the second stirring to 60 to 90 minutes, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. Moreover, it is advantageous for improving production efficiency and reducing production costs.

[0096] In some embodiments, the stirring time of the third stirring is 60 to 90 minutes, the revolution speed is 20 rpm to 30 rpm, and the rotation speed is 500 rpm to 800 rpm.

[0097] In some embodiments, the stirring time of the third stirring may be selected from any one of 60 minutes, 70 minutes, 80 minutes, and 90 minutes. In some embodiments, the revolution speed may be selected from any one of 20 rpm, 25 rpm, and 30 rpm. In some embodiments, the rotation speed may be selected from any one of 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, and 800 rpm.

[0098] In the third stirring, by adding the dry mixture produced in the first stirring to the adhesive produced in the second stirring and stirring slowly, the risk that the high molecular weight polymer in the first binder aggregates and gels is reduced, and the uniformity of kneading between materials is improved.

[0099] In some embodiments, the revolution speed of the fourth stirring is 20 rpm to 30 rpm, the rotation speed is 1000 rpm to 1400 rpm, and the stirring time is 90 minutes to 120 minutes.

[0100] In some embodiments, the revolution speed of the fourth stirring may be selected from 20 rpm, 25 rpm, or 30 rpm. In some embodiments, the rotation speed may be selected from 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, or 1400 rpm. In some embodiments, the stirring time may be selected from 90 minutes, 100 minutes, 110 minutes, or 120 minutes.

[0101] In some embodiments, in the fourth stirring, by rapidly stirring at a high stirring rotation speed, sufficient mixing and dispersion of the materials are achieved, whereby the paste satisfies the processability and electrical characteristics of the lithium-ion battery.

[0102] In any embodiment, the solid content of the positive electrode paste is 63% to 73%, and the initial viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s.

[0103] In some embodiments, the solid content of the positive electrode paste is 63% to 73%, and the initial viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s. In some embodiments, the initial viscosity of the positive electrode paste may be selected from any one of 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s, 12000 mPa·s, 13000 mPa·s, 14000 mPa·s, 15000 mPa·s, 16000 mPa·s, 17000 mPa·s, 18000 mPa·s, 19000 mPa·s, 20000 mPa·s, 22000 mPa·s, 23000 mPa·s, 24000 mPa·s, 25000 mPa·s, 26000 mPa·s, 27000 mPa·s, 28000 mPa·s, 29000 mPa·s, 30000 mPa·s, 30500 mPa·s, 31000 mPa·s, 32000 mPa·s, 33000 mPa·s, 34000 mPa·s, 35000 mPa·s.

[0104] The initial viscosity of the positive electrode paste refers to the viscosity at the time of shipment of the positive electrode paste, and the viscosity when the production of the positive electrode paste is completed and shipped is recorded as the initial viscosity of the positive electrode paste.

[0105] In the present application, the viscosity of the positive electrode paste can be measured using methods known in the art. For example, a rotational viscometer can be used to measure the viscosity of the paste. Select an appropriate rotor, fix the viscometer rotor, and place it below the viscometer rotor so that the paste just immerses the scale line of the rotor. Instrument model number: Shanghai Fangrui NDJ-5S, rotor: 63# (2000 - 10000 mPa·s), 64# (10000 - 50000 mPa·s), rotation speed: 12 rpm, test temperature: 25 °C, test time is 5 minutes, and read the data after the display stabilizes.

[0106] The initial viscosity of the positive electrode paste with a solid content of 63% - 73% is 8000 mPa·s - 35000 mPa·s. The positive electrode paste has good coating properties and processability, and widens the process window of the coating.

[0107] In some embodiments, the solvent used in the second stirring and the solvent used in the fourth stirring are the same. With respect to the total mass of the conductive agent, the positive electrode active material, the first binder, and the second binder, the mass content of the solvent used in the second stirring is 35% - 40%, and the mass content of the solvent used in the fourth stirring is 5% - 10%.

[0108] In some embodiments, with respect to the total mass of the conductive agent, the positive electrode active material, the first binder, and the second binder, the mass content of the solvent used in the second stirring may be selected from 35%, 36%, 37%, 38%, 39% or 40%, and the mass content of the solvent used in the fourth stirring may be selected from 5%, 6%, 7%, 8%, 9% or 10%.

[0109] In some embodiments, in the positive electrode paste, the mass ratio of the positive electrode active material, the total mass of the first binder and the second binder, and the conductive agent is (82 to 95):(3 to 10):(2 to 8). In some embodiments, in the positive electrode paste, the mass ratio of the positive electrode active material, the total mass of the first binder and the second binder, and the conductive agent may be selected from any one of 95:3:2, 94:4:2, 93:5:2, 92:5:3, 91:6:3, 90:8:2, 90:5:5, 90:7:2, 88:8:4, 88:5:7, 82:10:8.

[0110] The positive electrode paste within the above range not only has good processability, but also has excellent electrical and chemical properties of the formed positive electrode sheet.

[0111] In some embodiments, the positive electrode active material is one or more of lithium iron phosphate, lithium cobalt oxide, and lithium manganate.

[0112] By using the above positive electrode active material, the energy density of the battery is increased, which is advantageous for improving the cycle characteristics of the battery.

[0113] In some embodiments, the conductive agent is one or more of conductive carbon black, graphite, and carbon nanotubes.

[0114] The above conductive agent is advantageous for improving the conductivity of the battery.

[0115] The present application provides a positive electrode paste manufactured by the manufacturing method in any embodiment of the present application.

[0116] In some embodiments, the solid content of the positive electrode paste is 63% to 73%, and the initial viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s, and after standing for 24 hours, the viscosity of the positive electrode paste does not exceed 48000 mPa·s. In some embodiments, the initial viscosity of the positive electrode paste may be selected from any one of 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s, 12000 mPa·s, 13000 mPa·s, 14000 mPa·s, 15000 mPa·s, 16000 mPa·s, 17000 mPa·s, 18000 mPa·s, 19000 mPa·s, 20000 mPa·s, 22000 mPa·s, 23000 mPa·s, 24000 mPa·s, 25000 mPa·s, 26000 mPa·s, 27000 mPa·s, 28000 mPa·s, 29000 mPa·s, 30000 mPa·s, 30500 mPa·s, 31000 mPa·s, 32000 mPa·s, 33000 mPa·s, 34000 mPa·s, 35000 mPa·s. In some embodiments, after standing for 24 hours, the viscosity of the positive electrode paste may be selected from any one of 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s, 12000 mPa·s, 13000 mPa·s, 14000 mPa·s, 15000 mPa·s, 16000 mPa·s, 17000 mPa·s, 18000 mPa·s, 19000 mPa·s, 20000 mPa·s, 22000 mPa·s, 23000 mPa·s, 24000 mPa·s, 25000 mPa·s, 26000 mPa·s, 27000 mPa·s, 28000 mPa·s, 29000 mPa·s, 30000 mPa·s, 30500 mPa·s, 31000 mPa·s, 32000 mPa·s, 33000 mPa·s, 34000 mPa·s, 36000 mPa·s, 38000 mPa·s, 40000 mPa·s, 42000 mPa·s, 44000 mPa·s, 48000 mPa·s.

[0117] The positive electrode paste has appropriate viscosity, excellent stability, and good processability.

[0118] [Positive Electrode Sheet] The present invention provides a positive electrode sheet 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 the positive electrode film layer is manufactured by the manufacturing method in any embodiment of the present application. 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.

[0119] In some embodiments, a metal foil or a composite current collector can be used as the positive electrode current collector. As the metal foil, for example, an aluminum foil can be used. The composite current collector can include a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer material base (such as a base of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0120] In some embodiments, a positive electrode active material known in the art for use in batteries can be used as the positive electrode active material. As an example, the positive electrode active material may include at least one of 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 used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include lithium cobalt oxide (LiCoO 2 etc.), lithium nickel oxide (LiNiO 2 etc.), lithium manganese oxide (LiMnO 2 , LiMn 2 O 4etc.), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (NCM 333 also called), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM 523 also called) LiNi 0.5 Co 0.25 Mn 0.25 O 2 (NCM 211 also called), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622 also called), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811 also called), lithium nickel cobalt aluminum oxide (LiNi 0.85 Co 0.15 Al 0.05 O 2 etc.) and at least 1 one of its modified compounds may be included, but not limited thereto. As the olivine-structured lithium-containing phosphate, for example, lithium iron phosphate (e.g., LiFePO 4 (also called LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (LiMnPO 4 etc.), 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 may be included, but not limited thereto.

[0121] In some embodiments, the adhesion force per unit length between the positive electrode film layer and the positive electrode current collector is greater than 20 N / m. In some embodiments, the adhesion force per unit length between the positive electrode film layer and the positive electrode current collector is selectively 20 N / m to 30 N / m. In some embodiments, the adhesion force per unit length between the positive electrode film layer and the positive electrode current collector may be selected from any one of 20 N / m, 20.5 N / m, 21 N / m, 21.5 N / m, 22 N / m, 22.5 N / m, 23 N / m, 23.5 N / m, 24 N / m, 24.5 N / m, 25 N / m, 27 N / m, 30 N / m.

[0122] In this specification, the adhesion force is mainly used to characterize the adhesion strength between the film layer manufactured from the positive electrode paste in the positive electrode sheet and the current collector, and can be measured by any known method. As an example, the adhesion force per unit length between the positive electrode film layer and the positive electrode current collector can be measured using methods known in the art. For example, referring to the national standard GB-T2790-1995 "Adhesives - 180° Peel Strength Test Method", the process of the adhesion force test in the examples and comparative examples of this application is as follows. Cut a sample with a width of 30 mm and a length of 100 - 160 mm with a blade, attach a special double-sided tape to the steel plate, with a width of 20 mm and a length of 90 - 150 mm. After pasting the coating surface of the previously cut polar sheet sample on the double-sided tape, roll it 3 times along the same direction with a 2 kg pressure roller. Fix a paper tape with the same width as the polar sheet and a length of 250 mm to the polar sheet current collector and fix it with masking tape. Turn on the power of the tensile device of Sansi Co., Ltd. (sensitivity is 1 N), turn on the indicator light, adjust the stopper to an appropriate position, and fix one end of the steel plate where the polar sheet is not pasted with the lower clamp. Fold the paper tape upwards and fix it with the upper clamp, and adjust the position of the upper clamp with the "up" and "down" buttons of the manual controller attached to the tensile device. Then conduct the test and read the numerical value. The tensile speed is 50 mm / min. Divide the force when the force received by the polar sheet is balanced by the width of the tape to obtain the adhesion force of the polar sheet per unit length, and characterize the adhesion strength between the positive electrode film layer and the current collector.

[0123] [Negative electrode sheet] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer containing a negative electrode active material and provided on at least one surface of the negative electrode current collector.

[0124] 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.

[0125] In some embodiments, a metal foil or a composite current collector can be used as the negative electrode current collector. As the metal foil, for example, a copper foil can be used. The composite current collector can include a polymer base layer and a metal layer formed on at least one surface of the polymer 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) on a polymer material base (such as a base of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0126] In some embodiments, known negative electrode active materials for batteries can be used as the negative electrode active material. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material can be selected from at least one of silicon alone, silicon oxide, silicon carbon composite, silicon nitride composite, and silicon alloy. The tin-based material can be selected from at least one of tin element, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of the battery may be used. These negative electrode active materials may be used alone or in combination of two or more.

[0127] In some embodiments, the negative electrode film layer can optionally further include a binder. The binder can be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0128] In some embodiments, the negative electrode film layer can optionally further include a conductive agent. The conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0129] In some embodiments, the negative electrode film layer further optionally includes other auxiliaries such as a thickening agent (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0130] In some embodiments, the negative electrode sheet can be manufactured by the following method. Components for manufacturing the negative electrode sheet, such as a negative electrode active material, a conductive agent, a binder, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode paste. The negative electrode paste is coated on a negative electrode current collector, and through steps such as drying and cold pressing, a negative electrode sheet can be obtained.

[0131] [Electrolyte] The electrolyte plays a role in conducting ions between the positive electrode sheet and the negative electrode sheet. The present application does not particularly limit the type of electrolyte, and it can be selected as needed. For example, the electrolyte can be liquid, gel, or a complete solid.

[0132] In some embodiments, an electrolytic solution is used as the electrolyte. The electrolytic solution contains an electrolyte salt and a solvent.

[0133] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis(oxalate) borate, lithium difluorooxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0134] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, 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.

[0135] In some embodiments, the electrolyte solution further selectively contains an additive. For example, the additive may include a negative electrode film-forming additive and a positive electrode film-forming additive, and further may include an additive that can improve specific characteristics of the battery, such as an additive that improves overcharge characteristics of the battery, an additive that improves high-temperature or low-temperature characteristics of the battery, and the like.

[0136] [Separator] In some embodiments, the secondary battery further includes a separator. The present application does not particularly limit the type of the separator, and any known porous structure separator having good chemical stability and mechanical stability can be selected.

[0137] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, and are not particularly limited.

[0138] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be manufactured into an electrode assembly through a winding process or a lamination process.

[0139] In some embodiments, the secondary battery can include an exterior material. The exterior material is used to enclose the above electrode assembly and electrolyte.

[0140] In some embodiments, the exterior material of the secondary battery may be a hard case such as a hard plastic case, an aluminum case, or a steel case. The exterior material of the secondary battery may also be a soft pack such as a pouch-type soft pack. The material of the soft pack may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0141] The present application does not particularly limit the shape of the secondary battery, and it may be cylindrical, rectangular, or any other arbitrary shape. For example, FIG. 1 shows a rectangular-structured secondary battery 5 as an example.

[0142] In some embodiments, referring to FIG. 2, the exterior material can include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and side plates connected to the bottom plate, and an accommodation cavity surrounded by the bottom plate and the side plates is formed. The housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can be covered on the opening to seal the accommodation cavity. The positive electrode sheet, the negative electrode sheet, and the separator can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is enclosed in the accommodation cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art can select according to specific actual requirements.

[0143] In some embodiments, the secondary battery can be assembled into a battery module, and the number of secondary batteries included in the battery module may be one or more. The specific number can be selected by those skilled in the art according to the use and capacity of the battery module.

[0144] FIG. 3 shows a battery module 4 as an example. Referring to FIG. 3, in the battery module 4, a plurality of secondary batteries 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other method. Further, the plurality of secondary batteries 5 can be fixed by fasteners.

[0145] Optionally, the battery module 4 may further include an outer case having an accommodation space for accommodating a plurality of secondary batteries 5.

[0146] In some embodiments, the above battery module can be further assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more. The specific number can be selected by those skilled in the art according to the use and capacity of the battery pack.

[0147] Figures 4 and 5 show a battery pack 1 as an example. Referring to Figures 4 and 5, the battery pack 1 can include a battery case and a plurality of battery modules 4 installed in the battery case. The battery case includes an upper housing 2 and a lower housing 3. The upper housing 2 can cover the lower housing 3 and form a sealed space for accommodating the battery module 4. The plurality of battery modules 4 can be arranged in the battery case in any manner.

[0148] In addition, the present application further provides a power consumption device including at least one of a secondary battery, a battery module, or a battery pack according to the present application. The secondary battery, the battery module, or the battery pack may be used as a power source of the power consumption device or as an energy storage element of the power consumption device. The power consumption device can include, but is not limited to, mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), trains, ships, satellites, energy storage systems, etc.

[0149] As the power consumption device, a secondary battery, a battery module, or a battery pack can be selected according to its usage requirements.

[0150] Figure 6 shows a power consumption device as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirements of high output and high energy density for the secondary battery of the power consumption device, a battery pack or a battery module can be used.

[0151] Another example of the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is generally required to be lightweight and thin, and a secondary battery can be used as a power source.

[0152] Embodiment Hereinafter, embodiments of the present application will be described. The embodiments 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 indicated in the embodiments, they are implemented according to the technologies or conditions described in the literature of this field or according to the product manuals. When the manufacturer of the reagents or equipment used is not indicated, all are common commercially available products.

[0153] I. Manufacturing Method Example 1 1) Manufacture of the positive electrode paste Weighing of raw materials: Weigh the raw materials according to the mixing ratio of the positive electrode paste so that the mass ratio of the positive electrode active material: the first binder: the second binder: the conductive agent is 95:1.5:1.5:2. The mass of the positive electrode active material is 1200 kg, the positive electrode active material is lithium iron phosphate, the first binder is polyvinylidene fluoride with a weight average molecular weight of 2 million, the second binder is polyvinylidene fluoride with a weight average molecular weight of 1 million, and the conductive agent is conductive carbon black.

[0154] First stirring: Mix lithium iron phosphate, conductive carbon black and the first binder, and stir well. The revolution speed is 15 rpm, the rotation speed is 0, and the stirring time is 15 minutes to obtain a dry mixture.

[0155] Second stirring: Mix the second binder and the N-methylpyrrolidone (NMP) solvent, and stir well. The mass of the NMP solvent added in the second stirring is 35% of the total mass of the positive electrode active material, the first binder, the second binder and the conductive agent. The revolution speed is 25 rpm, the rotation speed is 1200 rpm, and the stirring time is 60 minutes to obtain an adhesive.

[0156] Third stirring: Add the above dry mixture to the above adhesive and stir well. The revolution speed is 25 rpm, the rotation speed is 600 rpm, and the stirring time is 60 minutes to obtain a primary paste.

[0157] 4th Stirring: Add NMP solvent to the above primary paste. The mass of the NMP solvent added in the 4th stirring is 10% of the total mass of the cathode active material, the 1st binder, the 2nd binder and the conductive agent. The revolution speed is 25 rpm, the rotation speed is 1200 rpm, and the stirring time is 110 minutes to obtain a cathode paste with a solid content of 68% ± 5%.

[0158] 2) Production of the polar sheet After uniformly coating the cathode paste produced in Example 1 on the cathode current collector aluminum foil, it is dried, cold-pressed and cut to obtain a cathode sheet.

[0159] Examples 2 - 3 The production method is basically the same as that of Example 1. The difference is that the 1st binder in the 1st stirring is adjusted to polyvinylidene fluoride with a weight average molecular weight of 4 million and polyvinylidene fluoride with a weight average molecular weight of 8 million respectively. The specific parameters are as shown in Table 1.

[0160] Examples 4 - 8 The production method is basically the same as that of Example 3. The difference is that the 2nd binder in the 2nd stirring is adjusted to polyvinylidene fluoride with a weight average molecular weight of 4 million, polyvinylidene fluoride with a weight average molecular weight of 3 million, polyvinylidene fluoride with a weight average molecular weight of 2 million, polyvinylidene fluoride with a weight average molecular weight of 1.5 million, and polyvinylidene fluoride with a weight average molecular weight of 0.5 million respectively. The specific parameters are as shown in Table 1.

[0161] Examples 9 - 12 The production method is basically the same as that of Example 3. The difference is that the mass ratio of the 1st binder to the 2nd binder is adjusted. The specific parameters are as shown in Table 1.

[0162] Examples 13 - 16 The manufacturing method is basically the same as that of Example 1. The difference is that the first binder is adjusted in the composition. Taking Example 13 as an example, the first binder is a composition of polyvinylidene fluoride with a weight average molecular weight of 2 million and polyvinylidene fluoride with a weight average molecular weight of 4 million. The polyvinylidene fluoride with a weight average molecular weight of 2 million in the first binder accounts for 30% of the total binder amount, the polyvinylidene fluoride with a weight average molecular weight of 4 million accounts for 40% of the total binder amount, and the polyvinylidene fluoride with a weight average molecular weight of 1 million in the second binder accounts for 30% of the total binder amount. For the specific parameters in other examples, they are as shown in Table 1.

[0163] Examples 17 to 44 The manufacturing method is basically the same as that of Example 3. The difference is that the stirring parameters of the first stirring and the second stirring are adjusted. The specific parameters are as shown in Table 1.

[0164] Comparative Example 1 Weighing of raw materials: Weigh the raw materials according to the mixing ratio of the positive electrode paste so that the mass ratio of the positive electrode active material: binder: conductive agent is 95:3:2. The mass of the positive electrode active material is 1200 kg. The positive electrode active material is lithium iron phosphate, the binder is polyvinylidene fluoride with a weight average molecular weight of 2 million, and the conductive agent is conductive carbon black.

[0165] First stirring: Mix lithium iron phosphate and conductive carbon black and stir well. The revolution speed is 15 rpm, the rotation speed is 0, and the stirring time is 15 minutes to obtain a dry mixture.

[0166] Second stirring: Mix the second binder and the NMP solvent and stir well. The mass of the added solvent is 35% of the total mass of the positive electrode active material, the binder, and the conductive agent. The revolution speed is 25 rpm, the rotation speed is 1200 rpm, and the stirring time is 60 minutes to obtain an adhesive.

[0167] 3rd Stirring: Add the dry mixture produced by the 1st stirring to the adhesive produced by the 2nd stirring, and stir well. The revolution speed is 25 rpm, the rotation speed is 600 rpm, and the stirring time is 60 minutes to obtain a primary paste.

[0168] 4th Stirring: Add NMP solvent to the primary paste. The mass of the added solvent is 10% of the total mass of the cathode active material, the binder, and the conductive agent. The revolution speed is 25 rpm, the rotation speed is 1200 rpm, and the stirring time is 110 minutes to obtain a cathode paste with a solid content of 68% ± 5%.

[0169] Comparative Examples 2 - 8 Basically the same as Comparative Example 1, the difference is that the weight average molecular weight of the binder was adjusted, and the specific parameters are as shown in Table 1.

[0170] II. Test Methods 1. Weight Average Molecular Weight Waters 2695 Isocratic HPLC gel chromatograph (differential refractive index detector 2141) was used. Using a polystyrene solution sample with a mass fraction of 3.0% as a reference, select a suitable chromatography column (oil-based: Styragel HT5DMF7.8×300 mm + Styragel HT4). Use purified N-methylpyrrolidone (NMP) solvent to prepare a 3.0% polymer solution, and let the prepared solution stand for one day for later use. During measurement, first aspirate tetrahydrofuran with a syringe, wash it, and repeat this several times. Next, aspirate 5 ml of the test solution, remove the air in the syringe, wipe the needle tip and dry it. Finally, slowly inject the sample solution into the injection port. After the display stabilizes, acquire the data and read the weight average molecular weight.

[0171] 2. Paste Viscosity Test Use a rotational viscometer to measure the viscosity of the paste. Select an appropriate rotor, fix the viscometer rotor, and place the paste below the viscometer rotor so that the paste just immerses the graduation line of the rotor. Instrument model: Shanghai Fangrui NDJ-5S, rotor: 63# (2000 - 10000 mPa·s), 64# (10000 - 50000 mPa·s), rotation speed: 12 rpm, test temperature: 25 °C, test time is 5 minutes, and read the data after the display stabilizes.

[0172] 3. Viscosity test after the paste is left standing for 24 hours After leaving the paste standing for 24 hours, re-measure the viscosity of the paste and use a rotational viscometer to measure the viscosity of the paste. Select an appropriate rotor, fix the viscometer rotor, and place the paste below the viscometer rotor so that the paste just immerses the graduation line of the rotor. Instrument model: Shanghai Fangrui NDJ-5S, rotor: 63# (2000 - 10000 mPa·s), 64# (10000 - 50000 mPa·s), rotation speed: 12 rpm, test temperature: 25 °C, test time is 5 minutes, and read the data after the display stabilizes.

[0173] 4. Gelation state test after the paste is left standing for 24 hours After leaving the paste standing for 24 hours, lift the paste in the beaker with a steel rule to judge the gelation state from the flowing state of the paste.

[0174] The non-gelled state is that the paste flows naturally and continuously, the paste advects on the surface of the steel scale, and there is no aggregation.

[0175] A slightly gelled state is that the paste flows naturally and continuously, but the fluid is thin, the paste basically spreads flat on the surface of the steel scale, but there are a few lumps.

[0176] A moderately gelled state is that the paste drips naturally, sometimes interrupts, the flow is discontinuous, the paste does not spread flat on the surface of the steel scale, and there are obvious lumpy aggregations.

[0177] A deep gelling state means that the paste cannot flow down, but falls in lumps, or remains on the steel scale without flowing down.

[0178] 5. Filtration Performance Test Take a 500 ml beaker and place it at the lower end of a 200-mesh filter holder. Take 500 ml of conductive paste, put it into the filter for filtration, and record the time when the volume of the paste in the beaker reaches 300 ml.

[0179] 6. Adhesion Test of Polar Sheet Referring to the national standard GB-T2790-1995 "Test Method for 180° Peel Strength of Adhesives", the process of the adhesion test of the examples and comparative examples of this application is as follows. Cut a sample with a width of 30 mm and a length of 100 - 160 mm with a blade, and attach a special double-sided tape to the steel plate, which is 20 mm wide and 90 - 150 mm long. First, attach the coating surface of the previously cut polar sheet sample to the double-sided tape, and then roll it 3 times along the same direction with a 2 kg pressure roller. Fix a paper tape with the same width as the polar sheet and a length of 250 mm to the polar sheet current collector, and fix it with masking tape. Turn on the power of the tensile device of Sansi Co., Ltd. (sensitivity is 1 N), turn on the indicator light, adjust the stopper to an appropriate position, and fix one end of the steel plate where the polar sheet is not attached with the lower clamp. Fold the paper tape upward and fix it with the upper clamp, and adjust the position of the upper clamp with the "up" and "down" buttons of the manual controller attached to the tensile device. Then conduct the test and read the numerical value. The tensile speed is 50 mm / min. Divide the force when the force received by the polar sheet is balanced by the width of the tape to obtain the adhesion force of the polar sheet per unit length, and characterize the adhesion strength between the positive electrode film layer and the current collector.

[0180] III. Analysis of Test Results of Each Example and Comparative Example Manufacture the products of each example and comparative example according to the above method, and the results of measuring each performance parameter are as shown in Table 1 and Table 2 below.

[0181] Table 1 Manufacturing Parameters of Examples and Comparative Examples TIFF2025517221000002.tif241164 TIFF2025517221000003.tif199164 TIFF2025517221000004.tif199164 TIFF2025517221000005.tif199164 TIFF2025517221000006.tif199164 TIFF2025517221000007.tif177164

[0182] Table 2 Test Results of Performance Parameters of Examples and Comparative Examples TIFF2025517221000008.tif234155 TIFF2025517221000009.tif78155

[0183] As can be seen from the above results, all the positive electrode pastes in Examples 1 to 44 were manufactured using the paste manufacturing method disclosed in the present application, all of which included first stirring, second stirring, third stirring, and fourth stirring. In the first stirring, lithium iron phosphate as a positive electrode active material, conductive carbon black as a conductive agent, and polyvinylidene fluoride as a first binder were mixed and stirred to produce a dry mixture. In the second stirring, polyvinylidene fluoride as a second binder and NMP solvent were mixed and stirred to produce an adhesive. In the third stirring, the dry mixture and the adhesive were mixed and stirred to produce a primary paste. In the fourth stirring, the NMP solvent and the primary paste were mixed and stirred to produce a positive electrode paste. The weight average molecular weight of polyvinylidene fluoride in the second binder was smaller than the weight average molecular weight of any polyvinylidene fluoride in the first binder. As can be seen from the comparison between Examples 1 to 44 and Comparative Examples 1 to 8, the manufacturing method of the positive electrode paste according to the present application can effectively reduce the viscosity of the positive electrode paste and improve the processability of the paste. The manufacturing method is not only suitable for polymers in the prior art, but especially suitable for high molecular weight polymers and has wide versatility.

[0184] As can be seen from the comparison between Examples 3 to 8 and Comparative Example 6, by controlling the second binder to be polyvinylidene fluoride with a weight average molecular weight of 4 million or less, the viscosity at the time of shipment of the positive electrode paste and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Examples 3, 6 to 8 and Example 6, by controlling the second binder to be polyvinylidene fluoride with a weight average molecular weight of 2 million or less, the viscosity at the time of shipment of the positive electrode paste and the viscosity after standing for 24 hours can be further reduced, the gelation of the positive electrode paste can be alleviated to a considerable extent, and the filtration performance of the positive electrode paste can be improved. As can be seen from the comparison between Examples 3, 7 to 8 and Example 6, by controlling the second binder to be polyvinylidene fluoride with a weight average molecular weight of 1.5 million or less, the viscosity at the time of shipment of the positive electrode paste and the viscosity after standing for 24 hours can be further reduced, the gelation of the positive electrode paste can be significantly alleviated, and the filtration performance of the positive electrode paste can be improved.

[0185] As can be seen from the comparison between Examples 1 to 16 and Comparative Examples 1 to 8, the manufacturing method is suitable for polyvinylidene fluoride containing one or more weight average molecular weights in the first binder, and is particularly applicable to the first binder containing polyvinylidene fluoride with a weight average molecular weight of 2 million or more.

[0186] As can be seen from the comparison between Example 3, Examples 10 to 11 and Example 9, Example 12, by controlling the mass content of the second binder to 30% to 50% with respect to the total mass of the first binder and the second binder, the high adhesion performance of the high molecular weight polymer in the first binder can be fully exerted, not only improving the adhesiveness of the positive electrode sheet, but also guaranteeing the processability of the positive electrode paste. In particular, it is guaranteed that the viscosity at the time of shipment and the viscosity after standing for 24 hours are low, and it has excellent gelation prevention characteristics and filterability.

[0187] As can be seen from the comparison between Example 3, Examples 18 to 19 and Example 17, by controlling the revolution speed of the first stirring to 10 rpm to 20 rpm, the viscosity at the time of shipment and the viscosity after standing for 24 hours of the positive electrode paste can be effectively reduced, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 18 to 19 and Example 20, by controlling the revolution speed of the first stirring to 10 rpm to 20 rpm, on the premise of guaranteeing the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the manufacturing cost can be reduced.

[0188] As can be seen from the comparison between Example 3, Examples 22 to 23 and Example 21, by controlling the stirring time of the first stirring to 10 minutes to 25 minutes, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 22 to 23 and Example 24, by controlling the stirring time of the first stirring to 10 minutes to 25 minutes, on the premise of ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

[0189] As can be seen from the comparison between Example 3, Examples 26 to 27 and Example 25, by controlling the revolution speed of the second stirring to 20 rpm to 30 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 26 to 27 and Example 28, by controlling the revolution speed of the second stirring to 20 rpm to 30 rpm, the manufacturing cost can be reduced on the premise of ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet.

[0190] As can be seen from the comparison between Example 3, Examples 30 to 31 and Example 29, by controlling the rotation speed of the second stirring to 1000 rpm to 1400 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 30 to 31 and Example 32, by controlling the rotation speed of the second stirring to 1000 rpm to 1400 rpm, on the premise of ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the positive electrode paste can be relaxed and the manufacturing cost can be reduced.

[0191] As can be seen from the comparison between Example 3, Examples 34 to 35 and Example 33, by controlling the stirring time of the second stirring to 60 minutes to 90 minutes, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 34 to 35 and Example 36, by controlling the stirring time of the second stirring to 60 minutes to 90 minutes, on the premise of ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

[0192] As can be seen from the comparison between Example 3, Examples 38 to 39 and Example 37, by controlling the rotation speed of the third stirring to 500 rpm to 800 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 38 to 39 and Example 40, by controlling the rotation speed of the third stirring to 500 rpm to 800 rpm, while ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the cost can be reduced.

[0193] As can be seen from the comparison between Example 3, Examples 42 to 43 and Example 41, by controlling the rotation speed of the fourth stirring to 1000 rpm to 1400 rpm, the viscosity of the positive electrode paste at the time of shipment and the viscosity after standing for 24 hours can be effectively reduced, the gelation of the positive electrode paste can be alleviated, the filtration performance of the positive electrode paste can be improved, and the adhesiveness of the positive electrode sheet can be improved. As can be seen from the comparison between Example 3, Examples 42 to 43 and Example 44, by controlling the rotation speed of the fourth stirring to 1000 rpm to 1400 rpm, while ensuring the adhesiveness and filtration performance of the positive electrode paste and the adhesiveness of the positive electrode sheet, the manufacturing cost can be reduced.

[0194] As can be seen from the examples, the solid content of the positive electrode paste disclosed in the present application is 63% to 73%, and the viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s. The positive electrode paste has good coating properties and processability.

[0195] It should be noted that the present application is not limited to the above embodiments. The above embodiments are merely examples, and any embodiments that have substantially the same configuration as the technical idea and exhibit the same operational effects within the scope of the technical solution of the present application are included in the technical scope of the present application. Also, any various modifications that can be conceived by those skilled in the art and added to the embodiments, as well as other forms constructed by combining some components in the embodiments, are included in the scope of the present application without departing from the gist of the present application.

Explanation of Reference Numerals

[0196] 1 Battery Pack 2 Upper Housing 3 Lower Housing 4 Battery Module 5 Secondary Battery 51 Housing 52 Electrode Assembly 53 Cover Plate

Claims

1. including first stirring, second stirring, third stirring and fourth stirring, in the first stirring, a positive electrode active material, a conductive agent and a first binder are mixed and stirred to produce a dry mixture, in the second stirring, a second binder and a solvent are mixed and stirred to produce an adhesive, in the third stirring, the dry mixture and the adhesive are mixed and stirred to produce a primary paste, in the fourth stirring, a solvent and the primary paste are mixed and stirred to produce a positive electrode paste, A method for producing a positive electrode paste, characterized in that the weight average molecular weight of the polymer in the second binder is smaller than the weight average molecular weight of any polymer in the first binder.

2. The production method according to claim 1, characterized in that the second binder is polyvinylidene fluoride having a weight average molecular weight of 4 million or less.

3. The production method according to claim 1 or 2, characterized in that the second binder is polyvinylidene fluoride having a weight average molecular weight of 2 million or less.

4. The production method according to any one of claims 1 to 3, characterized in that the first binder includes polyvinylidene fluoride having one or more weight average molecular weights, and the first binder includes polyvinylidene fluoride having a weight average molecular weight of 2 million or more.

5. The production method according to any one of claims 1 to 4, characterized in that the first binder includes polyvinylidene fluoride having a weight average molecular weight of 4 million or more.

6. The production method according to any one of claims 1 to 5, characterized in that the mass content of the second binder is 30% to 50% with respect to the total mass of the first binder and the second binder.

7. The production method according to any one of claims 1 to 6, characterized in that the first stirring has a rotation speed of 0 and a revolution speed of 10 rpm to 20 rpm.

8. The production method according to any one of claims 1 to 7, characterized in that the stirring time in the first stirring is 10 minutes to 25 minutes.

9. The production method according to any one of claims 1 to 8, characterized in that the revolution speed of the second stirring is 20 rpm to 30 rpm.

10. The production method according to any one of claims 1 to 9, characterized in that the rotation speed of the second stirring is 1000 rpm to 1400 rpm.

11. The manufacturing method according to any one of claims 1 to 10, characterized in that the stirring time in the second stirring is 60 minutes to 90 minutes.

12. The third stirring has a stirring time of 60 minutes to 90 minutes, a revolution speed of 20 rpm to 30 rpm, and a rotation speed of 500 rpm to 800 rpm. The manufacturing method according to any one of claims 1 to 11, characterized in that.

13. The revolution speed of the fourth stirring is 20 rpm to 30 rpm, the rotation speed is 1000 rpm to 1400 rpm, and the stirring time is 90 minutes to 120 minutes. The manufacturing method according to any one of claims 1 to 12, characterized in that.

14. The solid content of the positive electrode paste is 63% to 73%, and the initial viscosity of the positive electrode paste is 8000 mPa·s to 35000 mPa·s. The manufacturing method according to any one of claims 1 to 13, characterized in that.

15. The solvent used in the second stirring and the solvent used in the fourth stirring are the same. With respect to the total mass of the conductive agent, the positive electrode active material, the first binder, and the second binder, the mass content of the solvent used in the second stirring is 35% to 40%, and the mass content of the solvent used in the fourth stirring is 5% to 10%. The manufacturing method according to any one of claims 1 to 14, characterized in that.

16. In the positive electrode paste, the mass ratio of the positive electrode active material, the total mass of the first binder and the second binder, and the conductive agent is (82 to 95):(3 to 10):(2 to 8). The manufacturing method according to any one of claims 1 to 15, characterized in that.

17. The positive electrode active material is one or more of lithium iron phosphate, lithium cobalt oxide, and lithium manganate. The manufacturing method according to any one of claims 1 to 16, characterized in that.

18. The conductive agent is one or more of conductive carbon black, graphite, and carbon nanotubes. The manufacturing method according to any one of claims 1 to 17, characterized in that.

19. A positive electrode paste characterized by being manufactured by the manufacturing method according to any one of claims 1 to 18.

20. The positive electrode paste according to claim 19, characterized in that the solid content is 63% to 73%, the initial viscosity is 8000 mPa·s to 35000 mPa·s, and after standing for 24 hours, the viscosity does not exceed 48000 mPa·s.

21. A positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode film layer is a positive electrode sheet manufactured from the positive electrode paste manufactured by the manufacturing method according to any one of claims 1 to 18.

22. The positive electrode sheet according to claim 21, characterized in that the adhesive force per unit length between the positive electrode film layer and the positive electrode current collector is greater than 20 N / m.

23. A secondary battery comprising a positive electrode sheet, a separator, a negative electrode sheet, and an electrolytic solution, wherein the positive electrode sheet is manufactured from the positive electrode paste manufactured by the manufacturing method according to any one of claims 1 to 18 or the positive electrode paste according to any one of claims 19 to 20.

24. The secondary battery according to claim 23, characterized in that it is any one of a lithium ion battery, a sodium ion battery, a magnesium ion battery, and a potassium ion battery.

25. A battery module characterized by including the secondary battery according to claim 23 or 24.

26. A battery pack characterized by including the secondary battery according to claim 23 or 24 or the battery module according to claim 25.

27. An electric power consumption device characterized by including at least one selected from the secondary battery according to claim 23 or 24, the battery module according to claim 25, and the battery pack according to claim 26.

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