Highly compacted dispersion material and method of making, highly compacted flexible positive electrode sheet

Abstract

The application belongs to the technical field of lithium ion battery auxiliary materials, and particularly relates to a high-compaction dispersing material and a preparation method thereof, and a high-compaction flexible positive electrode sheet, which comprises the following components in parts by mass: 30-40 parts of component A, 5-10 parts of component B, 5-10 parts of component C, and 40-60 parts of a solvent; wherein the component A comprises a solution polymerization copolymer of unsaturated cyclic monomers, unsaturated polyether, amine-containing monomers and (methyl) acrylate monomers; the component B comprises long-chain amine substances; and the component C comprises organic esters. The high-compaction dispersing material and the preparation method thereof, and the high-compaction flexible positive electrode sheet have the advantages of excellent dispersing performance, outstanding flexibility improvement effect, and significant improvement of electrode sheet compaction density, can balance the two functions of dispersion and compaction, reduce production cost, improve electrode sheet yield, and have a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery additive materials technology, specifically relating to a high-pressure compaction dispersion material and its preparation method, and a high-pressure compaction flexible positive electrode sheet. Background Technology

[0002] In recent years, with the booming development of China's new energy vehicle industry, lithium-ion batteries, the heart of new energy vehicles, have matured, and industry competition has become increasingly fierce. Lithium battery companies all have an urgent need to improve the energy density of individual cells and reduce costs. Lithium batteries generally consist of a positive electrode, a negative electrode, an electrolyte, and a separator. Without changing the existing battery structure and material system, a higher compaction density positive electrode helps to increase battery capacity and reduce internal resistance, thereby improving the energy density of individual battery cells.

[0003] The production of positive electrode sheets generally involves steps such as slurry preparation, coating, drying, rolling, and slitting. Increasing the compaction density of the electrode sheets requires greater pressure from the rolling equipment, which in turn makes the sheets brittle and prone to breakage. This poses a significant challenge to the rolling equipment and the stability of battery production. To improve production efficiency and electrode yield, lithium battery companies typically use dispersing materials to prepare the positive electrode slurry.

[0004] However, while existing dispersion materials can solve the problem of cathode slurry dispersion, they are insufficient to meet the need for high compaction and flexibility of the electrode. Developing a dispersion material that can improve compaction density has become a pressing technical problem in this field.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0006] This disclosure provides at least one high-pressure compaction dispersion material and its preparation method, as well as a high-pressure compaction flexible positive electrode sheet.

[0007] In a first aspect, embodiments of this disclosure provide a high-pressure compaction dispersion material comprising, by mass parts: 30-40 parts of component A, 5-10 parts of component B, 5-10 parts of component C, and 40-60 parts of solvent; wherein component A comprises a solution polymerization copolymer of unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, and (meth)acrylate monomers; component B comprises long-chain amines; and component C comprises organic esters.

[0008] In one optional embodiment, the mass ratio of the unsaturated cyclic monomer, the unsaturated polyether, the amine-containing monomer and the (meth)acrylate monomer is (3-6):1:(2-4):(1-2).

[0009] In one alternative embodiment, the unsaturated cyclic monomer comprises any one or more combinations of styrene, methylstyrene, vinylpyridine, and N-vinylpyrrolidone.

[0010] In one optional embodiment, the unsaturated polyether comprises any one or a combination of allyl polyether APEG-500, allyl polyether APEG-800, allyl polyether APEG-1000, allyl polyether APEG-1500, and allyl polyether APEG-2000.

[0011] In one alternative embodiment, the amine-containing monomer includes any one or a combination of acrylamide, N,N-dimethylacrylamide, isopropylacrylamide, and dimethylaminoethyl acrylate.

[0012] In one alternative embodiment, the (meth)acrylate monomers include any one or more combinations of butyl methacrylate, amyl methacrylate, hexyl methacrylate, butyl acrylate, hexyl acrylate, lauryl acrylate, etc.

[0013] In one alternative embodiment, the long-chain amine includes any one or a combination of erucamide, oleamide, stearamide, and ethylene bis-stearamide.

[0014] In one alternative embodiment, the organic ester includes any one or more combinations of dibutyl terephthalate, dioctyl terephthalate, dibutyl adipate, bis(2-ethylhexyl) adipate, and dioctyl sebacate.

[0015] In one alternative embodiment, the solvent includes any one of N-methylpyrrolidone and N-ethylpyrrolidone.

[0016] Secondly, this disclosure also provides a method for preparing the high-pressure compaction dispersion material as described above, comprising the following steps: Step S1, preparing component A, namely, adding unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, (meth)acrylate monomers and solvents to a reaction vessel, stirring evenly, evacuating and replacing with nitrogen, then heating and adding an initiator, stopping the reaction after a certain time and cooling down to discharge the material, obtaining component A; Step S2, adding component A, component B, component C and solvent to a reaction vessel, mixing evenly and then vacuum dehydrating, discharging the material after the moisture content is qualified, obtaining the high-pressure compaction dispersion material.

[0017] In one optional embodiment, the initiator includes any one or more combinations of azobisisobutyronitrile, azobisisoheptanenitrile, and benzoyl peroxide, and the amount of the initiator is 0.1%-2% of the sum of the amounts of the unsaturated cyclic monomers, amine-containing monomers, unsaturated polyethers, and (meth)acrylate monomers, calculated by mass percentage.

[0018] In one optional embodiment, the reaction temperature in step S1 is 60-90°C, and the reaction time is 2-10 h; the amount of solvent added in step S1 accounts for 40-60% of the total mass of component A.

[0019] Thirdly, this disclosure also provides a method for preparing a high-pressure compaction flexible positive electrode sheet, comprising the following steps: Step S1, adding the high-pressure compaction dispersion material, lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, and N-methylpyrrolidone as described above into a material tank, wherein the mass ratio of lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, N-methylpyrrolidone, and high-pressure compaction dispersion material is (94-96):(1-3):(1-3):(40-60):(0.2-0.5), and stirring evenly at room temperature to obtain a slurry; Step S2, coating the slurry onto aluminum foil using a coating machine, drying it in an oven at 120-140℃, and then rolling it using a roller press to obtain a high-pressure compaction flexible positive electrode sheet.

[0020] The beneficial effects of this high-compaction dispersion material, its preparation method, and the high-compaction flexible positive electrode sheet are as follows:

[0021] 1. Component A in this high-pressure compaction dispersion material provides a strong dispersing effect. The cyclic unsaturated monomers have certain van der Waals forces with the cathode particles and are adsorbed on the particle surface. The amine-containing monomers wet the surface of the cathode material particles, causing large particles to gradually open into smaller molecules, thereby reducing viscosity and maintaining the uniformity and stability of the cathode slurry. The acrylate monomers and polyether monomers have certain flexibility, which can reduce the rigidity of the dispersion material. At the same time, the large number of ester groups in the acrylate, together with the amide and polyether long chain groups, maintain the stable and uniform dispersion of the slurry system.

[0022] 2. Component B in this high-pressure compaction dispersion material can interact with the primary active material (e.g., lithium iron phosphate) in the positive electrode slurry system. The amide groups adsorb onto the surface of the positive electrode particles, while the aliphatic hydrophobic long chains extend outward and form a hydrophobic layer. This helps the positive electrode particles to slip during the rolling process, avoiding direct collision and compression, and significantly reducing the rolling pressure and the risk of electrode breakage.

[0023] 3. The C component in this high-pressure compaction dispersion material can interact with the binder, the second main component in the positive electrode slurry system. This organic ester can shuttle between the molecular chains of the binder, reducing its regularity and crystallinity, significantly improving the flexibility of the binder, and thus helping to improve the flexibility of the electrode during processing.

[0024] 4. This high-compaction dispersion material can simultaneously achieve dispersion, softening, and compaction without the addition of softening agents or other additives, simplifying the production process and reducing battery production costs.

[0025] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0029] In this document, as used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0030] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0031] First, the preparation of component A: Unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, (meth)acrylate monomers, and solvents are added to a reaction vessel and stirred until homogeneous. The vessel is then evacuated to remove oxygen and purged with nitrogen. The temperature is then raised to 60-90°C, and the initiator is added to the reaction vessel. The reaction is stopped after 2-10 hours, and the mixture is cooled and discharged to obtain component A. The mass ratio of the unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, and (meth)acrylate monomers is (3-6):1:(2-4):(1-2). The amount of initiator, calculated as a percentage by mass, is 0.1%-2% of the sum of the amounts of the unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, and (meth)acrylate monomers. The solvent accounts for 50% of the total mass of the dispersed components.

[0032] In some embodiments, specifically, the unsaturated cyclic monomer includes any one or more combinations of styrene, methylstyrene, vinylpyridine, and N-vinylpyrrolidone.

[0033] In some embodiments, specifically, the unsaturated polyether includes any one or a combination of allyl polyether APEG-500, allyl polyether APEG-800, allyl polyether APEG-1000, allyl polyether APEG-1500, and allyl polyether APEG-2000.

[0034] In some embodiments, specifically, the amine-containing monomer includes any one or more combinations of acrylamide, N,N-dimethylacrylamide, isopropylacrylamide, and dimethylaminoethyl acrylate.

[0035] In some embodiments, specifically, the (meth)acrylate monomers include any one or more combinations of butyl methacrylate, amyl methacrylate, hexyl methacrylate, butyl acrylate, hexyl acrylate, lauryl acrylate, etc.

[0036] In some embodiments, specifically, the solvent includes any one of N-methylpyrrolidone and N-ethylpyrrolidone.

[0037] In some embodiments, specifically, the initiator includes any one or more combinations of azobisisobutyronitrile, azobisisoheptanenitrile, and benzoyl peroxide, and the amount of the initiator is 0.1%-2% of the sum of the amounts of the unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers, and (meth)acrylate monomers, calculated by mass percentage.

[0038] Subsequently, the high-pressure compaction dispersion material was prepared by adding 30-40 parts of component A, 5-10 parts of component B, 5-10 parts of component C and 50 parts of solvent to the reaction vessel in sequence, mixing them evenly, and then dehydrating them under vacuum. After the moisture content was qualified, the material was discharged, which is the high-pressure compaction dispersion material.

[0039] In one alternative embodiment, the long-chain amine includes any one or a combination of erucamide, oleamide, stearamide, and ethylene bis-stearamide.

[0040] In some embodiments, specifically, the organic ester includes any one or more combinations of dibutyl terephthalate, dioctyl terephthalate, dibutyl adipate, bis(2-ethylhexyl) adipate, and dioctyl sebacate.

[0041] The above-mentioned well-mixed high-compact dispersion material is added to the positive electrode slurry. The mass ratio of lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, N-methylpyrrolidone, and high-compact dispersion material in the positive electrode slurry is 95.7:2:2:50:0.3. The preparation process of the positive electrode sheet is as follows: The positive electrode slurry is added to the tank at the above ratio all at once, and stirred at room temperature using a double planetary vacuum mixer (the rotation speed is set to 30±5 r / min for revolution and 1300±50 r / min for rotation, and the time is 4 hours) until uniform. The material is then discharged, and the uniformly dispersed slurry is coated on aluminum foil using a coating machine (the coating thickness is selected to be 300µm). The coated sample is then dried in a 130℃ oven and rolled to obtain the high-compact flexible positive electrode sheet.

[0042] Example 1 illustrates a method for preparing a high-pressure compaction dispersion material, as follows:

[0043] 1) Preparation of Dispersion Component A: First, 300g of unsaturated cyclic monomer styrene, 100g of allyl polyether (APEG-500), 400g of amine-containing monomer acrylamide, 200g of butyl methacrylate and 1000g of solvent N-methylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then the temperature was raised to 60℃, and 5g of initiator azobisisobutyronitrile was added to the reactor. After reacting for 10h, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0044] 2) Preparation of high-pressure compaction dispersion material: 300g of component A, 100g of component B erucamide, 100g of component C dibutyl terephthalate and 500g of solvent N-methylpyrrolidone synthesized in the previous step are added to the reaction vessel in sequence, mixed evenly and then dehydrated under vacuum. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0045] Example 2 illustrates a method for preparing a high-pressure compaction dispersion material, as follows:

[0046] 1) Preparation of Dispersion Component A: First, 400g of unsaturated cyclic monomer methylstyrene, 100g of allyl polyether (APEG-800), 300g of amine-containing monomer N,N-dimethylacrylamide, 200g of amyl methacrylate and 1000g of solvent N-methylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then, the temperature was raised to 70℃, and 10g of initiator azobisisoheptanenitrile was added to the reactor. After reacting for 6 hours, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0047] 2) Preparation of high-pressure compaction dispersion material: 350g of component A, 50g of component B oleamide, 100g of component C dioctyl terephthalate and 500g of solvent N-methylpyrrolidone synthesized in the previous step are added to the reaction vessel in sequence, mixed evenly and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0048] Example 3 illustrates a method for preparing a high-pressure compaction dispersion material, as follows:

[0049] 1) Preparation of Dispersion Component A: First, 500g of unsaturated cyclic monomer vinylpyridine, 100g of allyl polyether (APEG-1000), 300g of amine-containing monomer isopropylacrylamide, 100g of hexyl methacrylate and 1000g of solvent N-methylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then the temperature was raised to 80℃, and 20g of initiator benzoyl peroxide was added to the reactor. After reacting for 4 hours, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0050] 2) Preparation of high-pressure compaction dispersion material: 400g of component A, 50g of component B stearamide, 50g of component C dibutyl adipate and 500g of solvent N-methylpyrrolidone synthesized in the previous step are added to the reaction vessel in sequence, mixed evenly and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0051] Example 4 illustrates a method for preparing a high-pressure compaction dispersion material using the following steps:

[0052] 1) Preparation of Dispersion Component A: First, 600g of unsaturated cyclic monomer N-vinylpyrrolidone, 100g of allyl polyether (APEG-1500), 200g of amine-containing monomer dimethylaminoethyl acrylate, 100g of butyl acrylate and 1000g of solvent N-ethylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then the temperature was raised to 90℃, and 1g of initiator azobisisobutyronitrile was added to the reactor. After reacting for 2 hours, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0053] 2) Preparation of high-pressure compaction dispersion material: 300g of component A, 100g of component B ethylene bis-stearamide, 100g of component C bis(2-ethylhexyl) adipic acid ester and 500g of solvent N-ethylpyrrolidone were added to the reaction vessel in sequence, mixed evenly, and then vacuum dehydrated. After the moisture content was qualified, the material was discharged, which is the high-pressure compaction dispersion material.

[0054] Example 5 illustrates a method for preparing a high-pressure compaction dispersion material, as follows:

[0055] 1) Preparation of Dispersion Component A: First, 500g of unsaturated cyclic monomer N-vinylpyrrolidone, 100g of allyl polyether (APEG-2000), 200g of amine-containing monomer acrylamide, 200g of hexyl acrylate and 1000g of solvent N-ethylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then the temperature was raised to 60℃, and 30g of initiator azobisisoheptanenitrile was added to the reactor. After reacting for 10h, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0056] 2) Preparation of high-pressure compaction dispersion material: 350g of component A, 50g of component B erucamide, 100g of component C dioctyl sebacate and 500g of solvent N-ethylpyrrolidone synthesized in the previous step are added to the reaction vessel in sequence, mixed evenly and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0057] Example 6 illustrates a method for preparing a high-pressure compaction dispersion material using the following steps:

[0058] 1) Preparation of Dispersion Component A: First, 400g of unsaturated cyclic monomer N-vinylpyrrolidone, 100g of allyl polyether (APEG-500), 400g of amine-containing monomer N,N-dimethylacrylamide, 100g of lauryl acrylate and 1000g of solvent N-ethylpyrrolidone were added to the reactor. After stirring evenly, the oxygen was removed by vacuuming and nitrogen was replaced. Then the temperature was raised to 70℃, and 10g of initiator benzoyl peroxide was added to the reactor. After reacting for 10h, the reaction was stopped, the temperature was lowered and the material was discharged to obtain dispersion component A.

[0059] 2) Preparation of high-pressure compaction dispersion material: 400g of component A, 50g of component B oleamide, 50g of component C dibutyl terephthalate and 500g of solvent N-ethylpyrrolidone synthesized in the previous step are added to the reaction vessel in sequence, mixed evenly and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0060] Comparative Example 1

[0061] This comparative case demonstrates a method for preparing a high-pressure compaction dispersion material using the following steps:

[0062] The high-pressure compaction dispersion material contains only dispersion component A, with the following specific formulation: First, 500g of the unsaturated cyclic monomer vinylpyridine, 100g of allyl polyether (APEG-500), 300g of the amine-containing monomer isopropylacrylamide, 100g of hexyl methacrylate, and 1000g of solvent N-methylpyrrolidone are added to a reaction vessel. After stirring evenly, the vessel is evacuated to remove oxygen and then purged with nitrogen. Subsequently, the temperature is raised to 80℃, and 20g of the initiator benzoyl peroxide is added to the reaction vessel. The reaction is stopped after 4 hours, and the material is cooled and discharged to obtain dispersion component A. Then, 500g of component A and 500g of solvent N-methylpyrrolidone are added sequentially to the reaction vessel, mixed evenly, and then dehydrated under vacuum. After the moisture content meets the requirements, the material is discharged, which is the high-pressure compaction dispersion material.

[0063] Comparative Example 2

[0064] This comparative case demonstrates a method for preparing a high-pressure compaction dispersion material using the following steps:

[0065] The high-pressure compaction dispersion material contains only component B. Then, 500g of component B erucamide and 500g of solvent N-methylpyrrolidone are added to the reaction vessel in sequence, mixed evenly, and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0066] Comparative Example 3

[0067] This comparative case demonstrates a method for preparing a high-pressure compaction dispersion material using the following steps:

[0068] The high-pressure compaction dispersion material contains only component C. Subsequently, 500g of dibutyl terephthalate (component C) and 500g of N-methylpyrrolidone (solvent) are added sequentially to the reaction vessel, mixed evenly, and then vacuum dehydrated. After the moisture content is qualified, the material is discharged, which is the high-pressure compaction dispersion material.

[0069] Comparative Example 4

[0070] A commercially available general-purpose dispersion material, HF2918.

[0071] The preparation process of the positive electrode sheets in Examples 1-6 and Comparative Examples 1-4 above:

[0072] Lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, N-methylpyrrolidone, and the dispersion material prepared in the examples or comparative examples were added to the tank at a mass ratio of 95.7:2:2:50:0.3. The mixture was stirred at room temperature using a dual planetary vacuum mixer (rotation speed set to 30±5 r / min revolution speed and 1300±50 r / min rotation speed, time 4h) until uniform. The uniformly dispersed slurry was then coated on aluminum foil using a coating machine (coating thickness selected as 300µm). The coated sample was then baked and dried in a 130℃ oven and rolled to obtain a high-pressure compacted flexible positive electrode sheet.

[0073] The following are relevant tests for positive electrode slurry viscosity, positive electrode sheet flexibility, etc.

[0074] Table 1:

[0075]

[0076] Please refer to Table 1, which shows the test data for viscosity and electrode flexibility of the high-compaction dispersion slurry. From the slurry viscosity data in Table 1, it can be seen that: comparing the initial viscosity of the slurries from Examples 1-6 and Comparative Example 4, the Examples 1-6 have better dispersion effects. Compared with Comparative Examples 2 and 3, components B and C have certain dispersion effects, but they are not as good as component A designed in this invention. From the folding times and electrode roller pressure in the table, it can be seen that at a compaction density of 2.65 g / cm³, Comparative Example 1 only has component A without other softening components, resulting in a relatively brittle electrode. Furthermore, achieving the same compaction density requires higher roller pressure, posing a significant challenge and negative impact on the electrode production process. Comparative Example 4 lacks a softening effect, making the electrode prone to breakage. The bending resistance of the electrodes in Comparative Examples 2 and 3 is also lower than that of Examples 1-6. This indicates that using softening component B or component C alone cannot achieve a good softening and compaction effect; components A, B, and C need to work synergistically. When the compaction density is increased to 2.75 g / cm³... 3When the electrodes prepared using Examples 1-6 were coated and rolled normally, the electrodes prepared using Comparative Examples 1-4 broke. This result shows that conventional dispersion materials or single components cannot achieve the production and processing of electrodes with higher compaction density. The high-compaction dispersion material designed and prepared by this invention has excellent dispersion performance, can significantly improve the compaction density of the electrode, and can ensure that the electrode runs stably without breaking during the high-compaction coating and rolling process. This helps to improve the energy density of the battery and improve the production efficiency and yield of battery manufacturers.

[0077] In summary, the high-compaction dispersion material and its preparation method proposed in this invention, as well as the high-compaction flexible positive electrode sheet, have advantages such as excellent dispersion performance, outstanding flexibility enhancement effect, and significant improvement in electrode sheet compaction density. They can take into account both dispersion and compaction enhancement functions, reduce production costs, improve electrode sheet yield, and have good application prospects.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-compactibility dispersion material for a flexible positive electrode sheet, characterized by, By mass fraction, the following components are included: The A component 30-40 parts, the B component 5-10 parts, the C component 5-10 parts, the solvent 40-60 parts; wherein The A component includes a solution polymerized copolymer of unsaturated cyclic monomers, unsaturated polyethers, amine-containing monomers and (meth) acrylate monomers; The B component includes long-chain amine substances; The C component includes organic esters; The unsaturated cyclic monomer includes any one or more combinations of styrene, methylstyrene, vinylpyridine, N-vinylpyrrolidone; The unsaturated polyether includes any one or more combinations of allyl polyether APEG-500, allyl polyether APEG-800, allyl polyether APEG-1000, allyl polyether APEG-1500, allyl polyether APEG-2000; The amine-containing monomer includes any one or more combinations of acrylamide, N,N-dimethyl acrylamide, isopropyl acrylamide, dimethylaminoethyl acrylate; The (meth) acrylate monomer includes any one or more combinations of butyl methacrylate, pentyl methacrylate, hexyl methacrylate, butyl acrylate, hexyl acrylate, lauryl acrylate; The long-chain amine substance includes any one or more combinations of erucic acid amide, oleic acid amide, stearic acid amide, and ethylene bis-stearamide; The organic ester includes any one or more combinations of dibutyl terephthalate, dioctyl terephthalate, dibutyl adipate, bis(2-ethylhexyl) adipate, dioctyl sebacate.

2. The high-compaction dispersing material of claim 1, wherein The mass fraction ratio of the unsaturated cyclic monomer, the unsaturated polyether, the amine-containing monomer, and the (meth) acrylate monomer is (3-6):1:(2-4):(1-2).

3. The high-compaction dispersing material of claim 1, wherein The solvent includes any one of N-methyl pyrrolidone and N-ethyl pyrrolidone.

4. A method of producing a high-compact dispersion material as claimed in any one of claims 1 to 3, characterized in that, The following steps are included: Step S1, preparing the A component, that is The unsaturated cyclic monomer, the amine-containing monomer, the unsaturated polyether, the (meth) acrylate monomer, and the solvent are respectively added to a reaction container, stirred uniformly, vacuumed and replaced with nitrogen, then heated and an initiator is added, the reaction is stopped after a certain period of time and cooled to discharge, obtaining the A component; Step S2, the A component, the B component, the C component, and the solvent are respectively added to a reaction container, mixed uniformly, then vacuum dehydrated, and discharged after the moisture is qualified, obtaining the high-compaction dispersing material.

5. The preparation method of the high-compaction dispersing material of claim 4, wherein The initiator includes any one or more combinations of azobisisobutyronitrile, azobisisoheptyl nitrile, and dibenzoyl peroxide, and the amount of the initiator is 0.1%-2% of the sum of the amounts of the unsaturated cyclic monomer, the unsaturated polyether, the amine-containing monomer, and the (meth) acrylate monomer, calculated by mass percentage.

6. The preparation method of the high-compaction dispersing material of claim 4, wherein The reaction temperature in the step S1 is 60-90℃, and the reaction time is 2-10h. The solvent is added in an amount of 40-60% of the total mass of the A component.

7. A method of making a high-density flexible positive electrode sheet, characterized by, The method comprises the following steps: Step S1: adding the high-compaction dispersion material, lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, and N-methylpyrrolidone according to any one of claims 1-3 into a tank, wherein the mass ratio of the lithium iron phosphate, conductive carbon black, polyvinylidene fluoride, N-methylpyrrolidone, and high-compaction dispersion material is (94-96):(1-3):(1-3):(40-60):(0.2-0.5), and stirring uniformly at room temperature to obtain a slurry; Step S2: coating the slurry on an aluminum foil through a coating machine, drying in an oven at 120-140℃, and then rolling through a roller press to obtain a high-compaction flexible positive electrode sheet.

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