CN-121983747-A - Coating slurry for lithium battery diaphragm, preparation method of lithium battery diaphragm, lithium battery and electric equipment

CN121983747ACN 121983747 ACN121983747 ACN 121983747ACN-121983747-A

Abstract

The application relates to the technical field of lithium ion batteries, and provides coating slurry for a lithium battery diaphragm, a preparation method of the lithium battery diaphragm, a lithium battery and electric equipment. The coating slurry for the lithium battery diaphragm is prepared by a preparation method of the coating slurry for the lithium battery diaphragm, and comprises the steps of sequentially dissolving a stabilizer, a sealing agent and a dispersing agent into pure water, uniformly stirring, and then blending with halloysite nanotubes or a load-type dispersion liquid taking the halloysite nanotubes as a carrier and a functional module material as a load, pre-dispersing the blending system, finely dispersing, and sequentially adding a polymer adhesive and a wetting agent under the stirring condition. The raw materials of the lithium battery separator comprise the coating slurry for the lithium battery separator. The preparation method of the lithium battery separator comprises the steps of coating the coating slurry for the lithium battery separator on a base film and then drying. The lithium battery includes the lithium battery separator. The power-related device includes the lithium battery.

Inventors

HU YIBO
WANG YULAI
JIANG YUZHEN
LIU ZHIPENG
Cui Bingshun
JI LIPENG

Assignees

青岛中科华联新材料股份有限公司

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (10)

1. The preparation method of the coating slurry for the lithium battery diaphragm is characterized by comprising the steps of sequentially dissolving a stabilizer, a sealing agent and a dispersing agent into pure water, uniformly stirring, then blending with halloysite nanotubes, pre-dispersing a blending system, then finely dispersing, and sequentially adding a polymer adhesive and a wetting agent under the stirring condition to obtain the coating slurry for the lithium battery diaphragm; Or alternatively The preparation method comprises the steps of sequentially dissolving a stabilizer, a sealing agent and a dispersing agent into pure water, uniformly stirring, then blending with a supported dispersion liquid taking halloysite nanotubes as a carrier and a functional module material as a carrier, pre-dispersing the blending system, then carrying out fine dispersion, and sequentially adding a polymer binder and a wetting agent under the stirring condition to obtain the coating slurry for the lithium battery diaphragm.
2. The method for preparing a coating paste for a lithium battery separator according to claim 1, wherein the pre-dispersing comprises stirring at a rotation speed of 1000-3000 rpm for 15-30min; And/or the number of the groups of groups, The fine dispersion comprises injecting the pre-dispersed slurry into a rod pin sand mill, and circularly grinding the slurry for at least 0.5h at a rotating speed of 500-2000 rpm by using zirconia beads of 0.1-0.8 mm; And/or the number of the groups of groups, The stabilizer comprises a water-soluble polymeric material; And/or the number of the groups of groups, The stabilizer comprises one or more of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, polymaleic anhydride and polyquaternium; And/or the number of the groups of groups, The sealing agent comprises one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene oxide and a silane coupling agent; And/or the number of the groups of groups, The dispersing agent comprises one or more of fatty acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester polyoxyethylene ether, natural high molecular derivatives, ethoxylated castor oil, dodecyl dimethyl betaine, cocamidopropyl betaine, sodium dodecyl aminopropionate, sodium cocoyl glutamate, polycarboxylate, polycarboxylic acid ether and high molecular polymers containing a plurality of anchoring groups and long solvated chains; Wherein the anchoring group comprises amine, carboxylic acid, phosphate, and the long solvated chain comprises polyester, polyether, polyolefin; And/or the number of the groups of groups, The polymer adhesive is selected from emulsion type acrylic ester polymer, solution type acrylic ester polymer, polyurethane polymer, polyacrylamide polymer, polyimide polymer and polyamide polymer; And/or the number of the groups of groups, The wetting agent is selected from organosilicon modified wetting agents, polyether wetting agents, alkynol wetting agents and alcohol wetting agents.
3. The method for preparing the coating slurry for the lithium battery separator according to claim 1, wherein the preparation step of the supported dispersion liquid using halloysite nanotubes as a carrier and functional module materials as a carrier comprises the steps of stirring the dispersion liquid or solution of the pretreated halloysite nanotubes and the functional module materials under vacuum for 0.5-2h, and then stirring the mixture at a low speed for 1h or more under normal pressure to obtain the supported dispersion liquid using the halloysite nanotubes as the carrier and the functional module materials as the carriers; the functional module comprises any one or a combination of a plurality of flame retardant modules, thermal shutdown modules, lithium supplementing modules, lithium guiding modules and interface stabilizing modules; In the supported dispersion, the mass ratio of the carrier to the load is 15:1-1:1.
4. The method for preparing a coating paste for a lithium battery separator according to claim 3, wherein the flame retardant module material comprises a thermal decomposition type flame retardant; And/or the number of the groups of groups, The flame retardant module material comprises ammonium polyphosphate; And/or the number of the groups of groups, The thermal shutdown module material comprises polyethylene wax or ethylene-vinyl acetate copolymer; And/or the number of the groups of groups, The lithium supplementing module material comprises lithium oxalate; And/or the number of the groups of groups, The lithium-conducting module material comprises polyethylene oxide; And/or the number of the groups of groups, The interface stabilization module material comprises fluoroethylene carbonate or vinylene carbonate; And/or the number of the groups of groups, The pretreatment comprises the steps of mixing 1-3 mol/L hydrochloric acid solution with natural halloysite nanotubes, stirring at a low speed for 0.5-1.5h, washing with deionized water for 2-3 times, draining, and vacuum drying at 90-120 ℃ for 2-3h, wherein the natural halloysite nanotubes account for 5-80% of the mass of the hydrochloric acid solution.
5. The coating paste for lithium battery separator prepared by the preparation method of the coating paste for lithium battery separator according to any one of claims 1 to 4, wherein the composition of the coating paste for lithium battery separator comprises, by mass, 10 to 60% halloysite nanotubes, 0 to 60% functional module materials, 0.1 to 5% stabilizers, 0.1 to 5% blocking agents, 0.1 to 5% dispersants, 3 to 20 wt% polymer binders, 0.05 to 4% wetting agents, and the balance being pure water.
6. A lithium battery separator, characterized in that the raw material of the lithium battery separator comprises the coating paste for a lithium battery separator according to claim 5.
7. A method for preparing the lithium battery diaphragm according to claim 6, wherein the method comprises the steps of coating the base film with the coating slurry, and then drying to obtain the lithium battery diaphragm.
8. The method for producing a lithium battery separator according to claim 7, wherein the base film comprises a wet polyolefin porous film, a dry polyolefin porous film, a spinning composite porous film, a nonwoven fabric porous film; And/or the number of the groups of groups, The coating mode comprises any one of micro-concave roller coating, reticulate pattern roller coating, spraying, slit coating and screw extrusion coating; And/or the number of the groups of groups, The drying is staged drying, and comprises a first stage drying, a second stage drying and a third stage drying which are sequentially carried out, wherein the first stage drying temperature is 40-65 ℃, the second stage drying temperature is 60-100 ℃, and the third stage drying temperature is 60-80 ℃. And/or the number of the groups of groups, The thickness of the coating is 0.5-4um.
9. A lithium battery comprising the lithium battery separator of claim 6.
10. An electric device is characterized in that, the electrical device comprising the lithium battery of claim 9.

Description

Coating slurry for lithium battery diaphragm, preparation method of lithium battery diaphragm, lithium battery and electric equipment Technical Field The application belongs to the technical field of lithium ion batteries, and particularly relates to coating slurry for a lithium battery diaphragm, a preparation method of the lithium battery diaphragm, a lithium battery and electric equipment. Background Lithium ion batteries have been widely used in consumer electronics, electric vehicles, and large-scale energy storage systems as a new generation of energy storage devices. The separator serves as one of the key components of the battery, and it mainly serves to isolate the positive and negative electrodes to prevent short circuits while allowing lithium ions to pass freely. The commercial separator mainly comprises polyolefin microporous films such as Polyethylene (PE) and polypropylene (PP), and the like, and has the inherent defects of poor heat stability, low melting point of polyolefin materials (PE is about 135 ℃ and PP is about 165 ℃), easy occurrence of large-area shrinkage and melting when the battery is overheated, causing thermal runaway caused by contact of positive and negative electrodes and even fire explosion, serious potential safety hazard, poor electrolyte wettability, low polyolefin material surface energy, strong lyophobicity, poor wettability and liquid retention of polar electrolyte, influence on ionic conductivity and multiplying power performance of the battery, limited mechanical strength, and difficulty in inhibiting penetration of lithium dendrites. Currently, the commercial diaphragm is mainly modified by a coating to improve the functionality of the diaphragm. Other functions of the diaphragm are mainly realized by the coating, and 2 functional coatings are widely applied in the field of wet diaphragm at present. An inorganic heat-resistant coating represented by alumina and boehmite improves the thermal stability and electrolyte affinity of a diaphragm, and a polymer adhesive coating represented by PVDF and PMMA can improve the adhesion degree of the diaphragm and a pole piece and improve the hardness and the cycle performance of an electric core. For wet-process diaphragms, with the development of industry, novel cell systems and application scenes put forward some new functional demands on the diaphragms, such as flame retardant function, lithium supplementing function, lyophile performance, thermal shutdown function, manganese metal capturing and the like. However, new functions are accompanied by the application of many new materials and require additional application of new coating structures on the membrane or the addition of functional new materials in conventional coating schemes. With the energy density requirements of the cell industry, wet process membranes with ever thinner thicknesses are more preferred for market selection. In the case of wet separators, particularly separators having a thickness of 12 μm or less, a heat-resistant coating is indispensable, and heat-resistant coating typified by a ceramic coating is currently the most effective method for improving the heat resistance of a separator. The main raw materials of the inorganic coating are inorganic materials such as alumina, boehmite and the like, the particle size Dv50 of the inorganic materials is generally 0.2-1 mu m, and the particle size determines the thickness of the coating taking the inorganic materials as the raw materials to be mostly 1-4 mu m. For most of the digital 3C and power cells, a polymer adhesive coating with the thickness of 1-3um is also required to be compounded to meet the requirements of the cell manufacturing process and the hardness. If other functions such as flame retardance, thermal shutdown, lithium supplementation and the like need to be applied to the diaphragm, a corresponding functional layer needs to be additionally coated on the basis. The additional functional coating can increase the overall thickness of the battery separator and bring about an increase in the air permeability value, resulting in a loss of cell energy density and ion conductivity, while the additional addition of functional materials to conventional coatings has material adaptation problems. In view of this, the present invention has been made. Disclosure of Invention The application aims to provide coating slurry for a lithium battery diaphragm, a preparation method of the coating slurry, a lithium battery and electric equipment, so as to solve the problems. In order to achieve the purposes of the application, the technical scheme adopted by the application is as follows: The application provides a preparation method of coating slurry for a lithium battery diaphragm, which comprises the steps of sequentially dissolving a stabilizer, a sealing agent and a dispersing agent into pure water, uniformly stirring, then blending with halloysite nanotubes, pre-dispersing a blending system, then finely d