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CN-119864374-B - Preparation method of lithium battery-structure integrated material

CN119864374BCN 119864374 BCN119864374 BCN 119864374BCN-119864374-B

Abstract

A preparation method of a lithium battery-structure integrated composite material belongs to the technical field of lithium battery preparation. The method comprises the steps of uniformly mixing epoxy resin, a diluent, a curing agent 1 and a lipophilic emulsifier to obtain a dispersion liquid 1, dripping an electrolyte solution into the dispersion liquid 1 at a constant speed, stirring at a constant temperature and a high speed to obtain a water-in-oil emulsion, uniformly mixing deionized water, the hydrophilic emulsifier and the curing agent 2 at a constant temperature to obtain a dispersion liquid 2, adding the water-in-oil emulsion into the dispersion liquid 2, emulsifying at a high speed to obtain a water-in-oil-in-water emulsion system, heating and curing the water-in-oil-in-water emulsion system, centrifuging, washing and drying after curing to obtain a solid nano adhesive, grinding the solid nano adhesive, and then uniformly paving the solid nano adhesive in a mold for high-temperature treatment to obtain the lithium battery diaphragm. The electrolyte solution is selected as the internal water phase of the water-in-oil emulsion, so that the internal osmotic pressure of the emulsion can be increased, fusion between the emulsions is prevented, and the particle size is increased.

Inventors

  • LI JUN
  • Zhu Pingwei
  • LIU LI
  • HUANG YUDONG

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260508
Application Date
20230131

Claims (10)

  1. 1. The preparation method of the lithium battery-structure integrated composite material is characterized by comprising the following steps: Uniformly mixing and dispersing epoxy resin, a diluent, a curing agent 1 and a lipophilic emulsifier to obtain a dispersion liquid 1, wherein the curing agent 1 is one or a mixture of maleic anhydride, phthalic anhydride, m-phenylenediamine, 3' -diethyl-4, 4' -diaminodiphenylmethane and 4,4' -diaminodiphenylmethane; Step two, dripping the electrolyte solution into the dispersion liquid 1 at a constant speed, and stirring at a constant temperature and a high speed to obtain water-in-oil emulsion; uniformly mixing and dispersing deionized water, a hydrophilic emulsifier and a curing agent 2 at constant temperature to obtain a dispersion liquid 2, wherein the curing agent 2 is one or a mixture of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine; Step four, adding the water-in-oil emulsion into the dispersion liquid 2, and continuously stirring and emulsifying at a high speed to obtain a water-in-oil-in-water emulsion system; Step five, heating the water-in-oil-in-water emulsion system, continuously stirring, and solidifying; Step six, centrifuging, washing and drying the solidified water-in-oil-in-water emulsion system to obtain a solid nano adhesive; Grinding the solid nano adhesive, uniformly spreading the ground solid nano adhesive in a stainless steel groove die, and performing high-temperature treatment under a certain pressure by using a hot press to obtain a lithium battery diaphragm, wherein the dosage of the solid nano adhesive in the step seven is 0.02-0.05 g, the high temperature is the curing temperature of the curing agent 1, the groove size of the stainless steel groove die is 40 multiplied by 10mm 3 , the thickness of the stainless steel groove die is initially controlled to be 0.05-0.1 mm by using a film coating knife when the nano adhesive is uniformly spread, and the pressure of the hot press is 1-2 MPa; Uniformly mixing and fully grinding a solid nano adhesive, a positive electrode active material and a conductive agent, spreading the mixed powder on an aluminum foil, and performing compression molding at high temperature by using a hot press to obtain the positive electrode of the lithium battery, wherein the mass ratio of the solid nano adhesive to the positive electrode active material is 1-3:17, and the mass ratio of the solid nano adhesive to the conductive agent is 1-2:1; uniformly mixing and fully grinding a solid nano adhesive, a negative electrode active material and a conductive agent, spreading the mixed powder on a copper foil, and performing compression molding at high temperature by using a hot press to obtain the negative electrode of the lithium battery, wherein the mass ratio of the solid nano adhesive to the negative electrode active material is 1-3:17, and the mass ratio of the solid nano adhesive to the conductive agent is 1-2:1; And step ten, stacking the lithium battery negative electrode plate, the lithium battery diaphragm, the dropwise adding electrolyte and the lithium battery positive electrode plate from bottom to top in sequence, and integrally hot-pressing and forming at high temperature by using a hot press.
  2. 2. The method for preparing the lithium battery-structure integrated composite material according to claim 1, wherein in the first step, the epoxy resin is at least one of bisphenol A epoxy resin, glycidyl ester epoxy resin and alicyclic epoxy resin, the diluent is at least one of ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether and butyl glycidyl ether, and the lipophilic emulsifier is at least one of span 20, span 40, span 60 and span 80.
  3. 3. The method for preparing a lithium battery-structure integrated composite material according to claim 2, wherein in the first step, the bisphenol A type epoxy resin is at least one of E55, E51 and E44, the glycidyl ester type epoxy resin is at least one of 711#, TDE-85# and 731#, and the alicyclic epoxy resin is at least one of W-95#,6221# and 6206#.
  4. 4. The preparation method of the lithium battery-structure integrated composite material is characterized in that in the first step, the mass ratio of the epoxy resin to the diluent is 3-6:1, the mass ratio of the epoxy resin to the curing agent 1 is 10:2-3, and the mass ratio of the epoxy resin to the lipophilic emulsifier is 5:2-5.
  5. 5. The method for preparing the lithium battery-structure integrated composite material, which is characterized in that in the second step, the mass ratio of the epoxy resin to the electrolyte solution is 5:2-5.
  6. 6. The method according to claim 1 or 5, wherein in the second step, the electrolyte solution is at least one of a sodium chloride solution of 0.1 mol/L, a potassium chloride solution of 0.1 mol/L, an NH 3 ·H 2 O-NH 4 Cl buffer of pH=10 and a sodium hydroxide solution of 0.1 mol/L.
  7. 7. The preparation method of the lithium battery-structure integrated composite material is characterized by comprising the following steps of, in the second step, the constant reaction temperature is 40-60 ℃, the time is 10-15 min, the stirring speed is 2500-3000 rpm, in the third step, the initial temperature is 40-50 ℃, in the fifth step, the temperature is raised to 60-80 ℃, the heating process is added with heat preservation and the reaction lasts for 25-30 minutes, and the stirring speed is 1000-1500 rpm.
  8. 8. The method for preparing the lithium battery-structure integrated composite material, which is disclosed in claim 1, is characterized in that in the third step, the hydrophilic emulsifier is one or a mixture of a nonionic emulsifier and an anionic emulsifier, the nonionic emulsifier is at least one of polyoxyethylene ether, OP-10 and polyvinyl alcohol, and the anionic emulsifier is at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and phosphate.
  9. 9. The preparation method of the lithium battery-structure integrated composite material is characterized in that in the third step, the mass ratio of deionized water to hydrophilic emulsifier is 15-20:1, the mass ratio of nonionic emulsifier to anionic emulsifier is 20:0-3, and the mass ratio of deionized water to curing agent 2 is 30-40:1.
  10. 10. The method for preparing the lithium battery-structure integrated composite material, which is disclosed in claim 1, is characterized in that in the fourth step, the mass ratio of deionized water to water-in-oil emulsion is 15-20:1.

Description

Preparation method of lithium battery-structure integrated material The application relates to a split application of 2023, 1 and 31 days, application number 2023100479284 and title of application, namely a preparation method of lithium battery dry electrode, diaphragm and battery-structure integrated material. Technical Field The invention belongs to the technical field of lithium battery preparation, and particularly relates to a preparation method of a lithium battery dry electrode, a diaphragm and a battery-structure integrated material. Background The preparation of the lithium ion battery electrode is realized by uniformly mixing an electrode active material, a conductive agent and a binder and then coating the mixture on a metal current collector. The electrode active material determines the energy density of the battery. The conductive agent can improve the transmission efficiency of electrons in the electrode, thereby improving the specific capacity and the rate charge-discharge capability of the battery. The main purpose of the adhesive is to adhere the electrode active material and the conductive agent to the metal current collector, so as to ensure the formation of a stable pole piece structure. The adhesive is used as one of inactive ingredients of positive and negative electrode materials of the lithium ion battery, and the adhesive has a very important effect on influencing the overall electrochemical performance of the battery, although the total mass of the electrode materials is only 1.5% -3%. Therefore, it can be said that the binder is a decisive battery element in a lithium ion battery and has a great influence on the actual capacity, rate capability and cycle life of the battery. At present, the adhesive is mainly of two types, namely an organic solvent soluble adhesive represented by polyvinylidene fluoride and a water soluble adhesive represented by carboxymethyl cellulose/styrene-butadiene rubber. Both have the common characteristics of requiring the participation of a liquid solvent, and the adhesive is an inactive ingredient, which may have adverse effects on the electron transport efficiency. Therefore, the conductive adhesive capable of realizing complete dry bonding is developed, so that the successful preparation of the dry electrode of the lithium battery is realized, and the conductive adhesive has remarkable practical significance. The separator is a critical component of a liquid lithium ion battery. The current liquid lithium ion battery mainly uses nonaqueous liquid electrolyte, a porous diaphragm is used between the anode and the cathode to isolate the anode from the cathode, short circuit is prevented, and lithium ions can be conducted in the electrolyte through a pore canal inside the diaphragm. As a separator for lithium ion batteries, it is necessary not only to isolate the positive and negative electrodes, but also to meet the requirements of other parameters (liquid absorption, porosity, electrochemical stability, thermal stability, mechanical properties, etc.). Currently, separators are mainly classified into commercial polyolefin separators, polyolefin modified separators, nonwoven fabrics separators, and the like. However, there are a number of technical bottlenecks currently present. For example, polyolefin has the problems of poor thermal stability, short circuit risk of battery caused by thermal shrinkage at high temperature, poor liquid absorption and retention, and the like. With the continuous progress of aviation technology, the growth of air traffic generally presents a significant upward trend. The growth of air traffic can lead to increased fuel burning and increased environmental pollution from air traffic. The aerospace industry (manufacturers and operators) is now introducing new technologies and operating schemes to reduce the fossil fuels consumed by aircraft. However, many years are required to reach the stage where all aircraft are replaced by new generation vehicles. An electric aircraft is an aircraft that uses an electric motor as a power unit, and the power supply includes batteries such as a storage battery, a fuel cell, a solar cell, and a supercapacitor. Currently, more successful unmanned electric aircraft mainly use a battery (mainly lithium battery electric aircraft), a solar cell (called solar aircraft), or a fuel cell as an electric power supply source. Electric propulsion systems have many important features, such as their very high efficiency of the energy conversion chain, even though some of them can achieve zero emissions. However, the difficulty of using electric propulsion systems in the field of aviation is significantly higher than in ground traffic. Because ground traffic can well address the extra weight issues created by imperfect electrical energy storage and propulsion technology, aircraft can be very weight sensitive. Therefore, a battery-structure integrated composite material is developed, and the lithium battery is