CN-121983749-A - Efficient closed-pore high-stability slurry, preparation method thereof, lithium ion battery and electric equipment

CN121983749ACN 121983749 ACN121983749 ACN 121983749ACN-121983749-A

Abstract

The application discloses a high-efficiency closed-cell high-stability slurry and a preparation method thereof, a lithium ion battery and electric equipment, and relates to the technical field of lithium batteries, wherein the high-efficiency closed-cell high-stability slurry comprises water, core-shell microspheres, a heat stabilizer, a wetting auxiliary agent and a dispersing auxiliary agent, the core-shell microspheres comprise first core-shell particles and second core-shell particles, the core of the first core-shell particles is a mixture of a heat conduction agent and a flame retardant or a composition of any one or more of the heat conduction agents, the shell of the first core-shell particles is a mixture of a heat sensitive promoter and a heat sensitive main agent or a composition of any one or more of the heat sensitive promoters, the core of the second core-shell particles is a mixture of a heat conduction agent and a flame retardant or a composition of any one or more of the flame retardants, and the shell of the second core-shell particles is a mixture of the heat sensitive promoter and the heat sensitive main agent or a composition of any one or more of the heat sensitive main agents. Has the advantages of early speed, synchronous response to temperature change, excellent thermal stability and flame retardance.

Inventors

LIU JINGJU
CHEN BAOHUI
LI BO
WEI HANXIN
LIU YUTAO
LV YANG
Chen kuo

Assignees

湖南防灾科技有限公司
国网湖南省电力有限公司防灾减灾中心
湖南省湘电试研技术有限公司

Dates

Publication Date: 20260505
Application Date: 20260403

Claims (10)

1. A high efficiency closed cell highly stable slurry comprising: The core-shell microsphere comprises first core-shell particles and second core-shell particles, wherein the core of the first core-shell particles is a mixture of a heat conduction agent and a flame retardant or a composition of any one or more of the heat conduction agents, the content of the heat conduction agent is larger than that of the flame retardant, the shell of the first core-shell particles is a mixture of a heat sensitive promoter and a heat sensitive main agent or a composition of any one or more of the heat sensitive promoters, the content of the heat sensitive promoter is larger than that of the heat sensitive main agent, the core of the second core-shell particles is a mixture of the heat conduction agent and the flame retardant or a composition of any one or more of the flame retardants, and the content of the flame retardant is larger than that of the heat conduction agent, and the shell of the second core-shell particles is a mixture of the heat sensitive promoter and the heat sensitive main agent or a composition of any one or more of the heat sensitive main agents, and the content of the heat sensitive main agent is larger than that of the heat sensitive promoter, and the mass ratio of the heat sensitive main agent to the heat sensitive main agent is 1:9-1; A heat stabilizer; Auxiliary aids including wetting aids and dispersing aids; Water; The core-shell microsphere comprises 25-40wt% of core-shell microsphere, 1-5wt% of heat stabilizer, 0.5-5wt% of auxiliary agent and 50-73.5wt% of water.
2. The efficient closed-cell high-stability slurry according to claim 1, wherein the melting point of the heat-sensitive main agent is greater than that of the heat-sensitive accelerator, the difference between the melting point of the heat-sensitive main agent and that of the heat-sensitive accelerator is 5-20 ℃, the particle size of the core-shell microsphere is 0.3-6 μm, the shell thickness of the first core-shell microsphere is 10% -25% of the radius of the first core-shell microsphere, and the shell thickness of the second core-shell microsphere is 10% -25% of the radius of the second core-shell microsphere.
3. The high efficiency closed cell highly stable slurry of claim 1 wherein the thermosensitive promoter is at least one of fischer-tropsch wax, palm wax, hydrogenated castor oil, microcrystalline wax, paraffin wax, montan wax, erucamide, candelilla wax, stearic acid, stearyl glycyrrhetinate, oleamide, ethylene-vinyl acetate wax, glyceryl stearate, stearyl alcohol, polycaprolactone, hydrogenated palm oil; The heat-sensitive main agent is at least one selected from stearic acid amide, ethylene-vinyl acetate copolymer, hydrogenated petroleum resin, polyethylene wax, polyacrylate, palmitamide, copolyester, oxidized polyethylene wax, lauramide, myristamide, behenamide, eicosamide, oxidized derivatives of montan wax and ethylene acrylic acid copolymer.
4. The high efficiency closed cell high stability slurry of claim 1, wherein the thermally conductive agent is at least one of single crystal thermally conductive alumina, zirconia, polycrystalline silicon nitride, aluminum nitride, zinc oxide, magnesium oxide, silica, molybdenum oxide, boron nitride, graphene, carbon nanotubes, carbon fibers; The heat stabilizer comprises at least one of polyacrylamide, polyacrylate, polyphthalamide, polyacrylonitrile, poly (p-phenylene terephthalamide), polyvinyl alcohol, acrylic acid and multipolymer of derivative.
5. The high efficiency, closed cell, high stability slurry of claim 1, wherein the flame retardant is at least one of polyphosphazene, ethoxy-pentafluoroethylcyclotriphosphazene, aluminum hypophosphite, diethyl ethylphosphonate, dimethoxy methyl phosphate, decabromodiphenyl ethane, triphenyl phosphate, triethyl phosphate, polymeric phosphate, antimony trioxide, trimethyl phosphate, trimethyl phosphite; the wetting auxiliary agent comprises at least one of diisooctyl succinate sodium sulfonate, alkylphenol ethoxylates, aliphatic polyether, polyethylene glycol, sodium alginate, hydroxyethyl cellulose, polyether ester and polyester; The dispersing aid is at least one selected from acrylic acid block copolymer, sodium carboxymethyl cellulose, acrylic acid polymer, sodium polyacrylate, sodium polycarboxylate, ammonium polyacrylate, maleic anhydride copolymer, sodium polystyrene sulfonate, polyacrylate copolymer, sodium lignin sulfonate, polyurethane and polyacrylic acid.
6. A method for preparing the high-efficiency closed-cell high-stability slurry according to any one of claims 1 to 5, comprising the following steps: s100, preparing first core-shell particles; s200, preparing second core-shell particles; S300, primarily mixing water, first core-shell particles, second core-shell particles and a dispersing aid to obtain a first mixture; S400, mixing the heat stabilizer with the first mixture to obtain a second mixture; and S500, mixing water, a wetting auxiliary agent and the second mixture to obtain the high-efficiency closed-cell high-stability slurry.
7. The method for preparing a high efficiency closed cell high stability slurry according to claim 6, wherein the step S100 comprises the steps of: S101, adding a first core-shell component into a planetary stirrer, and slowly adding the first core-shell core component in batches under a stirring state to obtain a first premix, wherein the stirring speed is 400-800 rpm, and the stirring time is 20-70 min; s102, transferring the first premix to a high-speed homogenizer for homogenizing and dispersing to obtain a second premix, wherein the dispersing speed is 1000-2000 rpm, and the dispersing time is 10-20 min; S103, transferring the second premix to a magnetic stirrer, adding water, and stirring at a low speed to obtain a first mixed solution, wherein the stirring speed is 50-300 rpm; s104, filtering and vacuum defoaming the first mixed liquid to obtain a first spray-dried feed liquid; s105, transferring the first spray-dried feed liquid to a spray dryer for spray drying to obtain first core-shell powder, wherein the inlet temperature of the spray drying is 80-110 ℃, the outlet temperature is 45-65 ℃, the feed rate is 6-10 mL/min, the atomization pressure is 1.5-2.5 bar, and the drying medium is nitrogen; and S106, collecting the dried first core-shell powder by using a cyclone separator, and performing heat treatment by using a vacuum drying oven to obtain first core-shell particles, wherein the heat treatment temperature is 40-60 ℃ and the time is 1-3.5 h.
8. The method for preparing a high efficiency closed cell high stability slurry according to claim 6, wherein the step S200 comprises the steps of: S201, adding the second core-shell component into a planetary mixer, and slowly adding the second core-shell core component in batches under the mixing state to obtain a third premix, wherein the mixing speed is 300-800 rpm, and the mixing time is 30-90 min; S202, transferring the third premix to a high-speed homogenizer for homogenizing and dispersing to obtain a fourth premix, wherein the dispersing speed is 1000-2000 rpm, and the dispersing time is 10-20 min; s203, transferring the fourth premixed solution to a magnetic stirrer, adding water, and stirring at a low speed to obtain a second mixed solution, wherein the stirring speed is 50-300 rpm; S204, filtering and vacuum defoaming the second mixed solution to obtain a second spray-dried feed solution; S205, transferring the second spray-dried feed liquid to a spray dryer for spray drying to obtain second core-shell powder, wherein the inlet temperature of the spray drying is 90-120 ℃, the outlet temperature is 55-75 ℃, the feed rate is 5-8 mL/min, the atomization pressure is 1.5-3.0 bar, and the drying medium is nitrogen; S206, collecting the dried first core-shell powder by using a cyclone separator, and performing heat treatment by using a vacuum drying oven to obtain the heat-sensitive main agent core-shell particles, wherein the heat treatment temperature is 45-70 ℃ and the heat treatment time is 1-2 hours.
9. The preparation method of the lithium ion battery is characterized by comprising the following steps of: s100, coating the high-efficiency closed-cell high-stability slurry according to any one of claims 1-2 on a first surface of a base film, and coating the high-efficiency closed-cell high-stability slurry on a second surface, opposite to the first surface, of the base film to obtain a safe composite membrane with the high-efficiency closed-cell high-stability slurry; S200, contacting a first surface of the safety composite diaphragm with a battery anode, contacting a second surface of the safety composite diaphragm with a battery cathode, and preparing a battery core through a winding or lamination process; and S300, assembling the battery core to obtain the lithium ion battery with the efficient closed-cell high-stability slurry.
10. An electrical device, wherein the electrical device uses the lithium ion battery prepared by the preparation method of the lithium ion battery as claimed in claim 9.

Description

Efficient closed-pore high-stability slurry, preparation method thereof, lithium ion battery and electric equipment Technical Field The application belongs to the technical field of lithium batteries, and particularly relates to high-efficiency closed-cell high-stability slurry, a preparation method thereof, a lithium ion battery and electric equipment. Background The safety performance of lithium ion batteries has been a key factor limiting their large-scale application, and in particular, the problem of thermal runaway has been the focus of much attention in the industry. The separator is a key component of the battery, and its thermal response characteristics are directly related to the overall safety of the battery. Currently, conventional polyolefin separators (e.g., PE, PP) rely primarily on the melting of the material itself at a specific temperature (typically PE of about 135 ℃ and PP of about 165 ℃) to achieve closed cells, which is a passive safety mechanism and the closed cell temperature is too high. In recent years, phase change materials have been introduced into membrane designs to block ion transport by undergoing a phase change at a specific temperature. For example, paraffin microspheres or polyethylene microspheres are applied as a heat sensitive material to the separator coating. These materials are capable of melting closed cells when the cell is abnormally heated. However, this approach has inherent disadvantages of 1, response hysteresis. The polyolefin has a relatively high melting phase transition enthalpy (e.g., about 200J/g for PE), and a large amount of heat is required to be absorbed to complete the phase transition, resulting in a slow closed cell response rate. In the initial phase of thermal runaway, this delay may miss the optimal intervention window to inhibit thermal runaway. 2. The closed cells are not uniform. The traditional diaphragm lacks an effective heat conduction network, can not rapidly diffuse heat when in local overheating, and is easy to cause asynchronism of closed pores to form local short circuit points. 3. The safety line is single. After closed pore, only physical isolation is needed, if the temperature is continuously increased, the shrinkage and rupture of the diaphragm still can cause short circuit, no chemical flame retardant mechanism is used for inhibiting the combustion of electrolyte, in addition, the bonding strength of the functional coating and the base film is insufficient at high temperature, and the coating is easy to fall off. Therefore, developing a novel membrane coating slurry which can respond to temperature changes rapidly and synchronously at an early stage, has excellent thermal stability and flame retardance, and is firmly combined with a base membrane at a high temperature becomes a technical problem to be solved in the art. Disclosure of Invention The application provides high-efficiency closed-cell high-stability slurry, a preparation method thereof, a lithium ion battery and electric equipment, and aims to solve the technical problem of novel diaphragm coating slurry which has the advantages of early quick response temperature change, excellent heat stability and flame retardance, firm combination with a base film at high temperature and the like to a certain extent. In a first aspect, the application provides a high-efficiency closed-cell high-stability slurry, which comprises water, core-shell microspheres, a heat stabilizer and an auxiliary agent, wherein the core-shell microspheres comprise first core-shell particles and second core-shell particles, the core of the first core-shell particles is a mixture of a heat conducting agent and a flame retardant or a composition of any one or more of the heat conducting agents, the content of the heat conducting agent is greater than the content of the flame retardant, and the shell of the first core-shell particles is a mixture of a heat sensitive promoter and a heat sensitive main agent or a composition of any one or more of the heat sensitive promoters, and the content of the heat sensitive promoter is greater than the content of the heat sensitive main agent; the core of the second core-shell particles is a mixture of a heat conducting agent and a flame retardant or a composition of any one or more of the flame retardants, the content of the flame retardant is larger than that of the heat conducting agent, the shell of the second core-shell particles is a mixture of a heat sensitive promoter and a heat sensitive main agent or a composition of any one or more of the heat sensitive main agents, the content of the heat sensitive main agent is larger than that of the heat sensitive promoter, the mass ratio of the heat sensitive main agent to the heat sensitive promoter in the core-shell microspheres is 1:9-9:1, the auxiliary agent comprises a wetting auxiliary agent and a dispersing auxiliary agent, the content of water is 50-73.5wt%, the content of the core-shell microspheres is 25-4