Search

CN-121975495-A - Preparation method of silicon-based aerogel composite phase-change material heat insulation felt

CN121975495ACN 121975495 ACN121975495 ACN 121975495ACN-121975495-A

Abstract

The invention relates to the field of composite materials and discloses a preparation method of a silicon-based aerogel composite phase-change material heat-insulating felt, which comprises the steps of 1) preparing N-isopropyl acrylamide, a hydrophobic monomer, a cross-linking agent and water into a pre-reaction liquid, 2) mixing paraffin emulsion and the pre-reaction liquid to initiate an interfacial polymerization reaction to obtain phase-change microcapsules, 3) adjusting a water glass solution to pH=2-4 to obtain sol, adding the phase-change microcapsules to pH=5-6 to obtain silica sol loaded with the phase-change microcapsules, and 4) immersing a glass fiber felt in the silica sol loaded with the phase-change microcapsules, and freeze-drying to obtain the silicon-based aerogel composite phase-change material heat-insulating felt. The interface compatibility of the paraffin and the silicon-based aerogel in the heat insulation felt is good, leakage is not easy, and the negative influence of the paraffin with high heat conductivity coefficient on the heat insulation performance of the silicon-based aerogel with low heat conductivity coefficient is avoided, so that the silicon-based aerogel composite phase-change material heat insulation felt still has excellent heat insulation effect at high temperature.

Inventors

  • YU HONGWEI
  • Jin Miaoqian
  • DING KAI
  • FAN YAN

Assignees

  • 浙江葆润应用材料有限公司

Dates

Publication Date
20260505
Application Date
20251217

Claims (10)

  1. 1. A preparation method of a silicon-based aerogel composite phase-change material heat insulation felt is characterized by comprising the following steps of: 1) Preparing a pre-reaction solution from N-isopropyl acrylamide, a hydrophobic monomer, a cross-linking agent and water, wherein the hydrophobic monomer is N-tertiary butyl acrylamide, and the mass ratio of the N-isopropyl acrylamide to the hydrophobic monomer is 3:0.3-0.5; 2) Mixing paraffin emulsion with the pre-reaction liquid, initiating interfacial polymerization reaction, purifying, and freeze-drying to obtain phase-change microcapsule; 3) Adding phase-change microcapsules at the temperature of less than or equal to 25 ℃ and adjusting the pH value to be between 5 and 6 to obtain silica sol loaded with the phase-change microcapsules; 4) And (3) immersing the heat-insulating base material in silica sol loaded with phase-change microcapsules at the temperature of less than or equal to 25 ℃ and freeze-drying to obtain the silicon-based aerogel composite phase-change material heat-insulating felt.
  2. 2. The process according to claim 1, wherein in step 1), The cross-linking agent is N, N' -methylene bisacrylamide; The mass ratio of the N-isopropyl acrylamide to the cross-linking agent is 20-40:1.
  3. 3. The process according to claim 1, wherein in step 2), The mass ratio of the paraffin emulsion to the pre-reaction liquid is 1:1-4; the interfacial polymerization reaction is carried out at the reaction temperature of 170-190 ℃ and the stirring speed of 300-700rpm for 3-5h.
  4. 4. The method according to claim 1 or 3, wherein in step 2), the purification comprises centrifugally washing the reaction solution to remove the supernatant, washing the obtained precipitate with an ethanol/water mixture to remove the unreacted monomers.
  5. 5. The method according to claim 1 or 3, wherein in the step 2), the freeze-drying comprises pre-freezing the phase-change microcapsule at-55 ℃ to-45 ℃ for 4-8 hours, and then performing two-stage freeze-drying, wherein the conditions are that: the first stage is that the vacuum pressure is 10-30Pa, the temperature is-40 ℃ to-20 ℃, the temperature rising rate is 0.8-1.2 ℃ per minute, and the time is 20-30 hours; And the second stage, wherein the vacuum pressure is less than 5Pa, the temperature is between-20 ℃ and 25 ℃, the temperature rising rate is between 0.8 and 1.2 ℃ per minute, and the time is between 10 and 15 hours.
  6. 6. The method according to claim 1, wherein in the step 2), the paraffin emulsion is prepared by heating and mixing paraffin with an oil phase solvent uniformly to obtain an oil phase, mixing an emulsifier with water, stirring to be transparent to obtain a water phase, dripping the oil phase into the water phase, and homogenizing to obtain the oil-in-water type paraffin emulsion.
  7. 7. The process according to claim 6, wherein in step 2), The paraffin comprises one or more of microcrystalline paraffin, full refined paraffin, semi refined paraffin and Fischer-Tropsch synthetic paraffin; the ratio of the paraffin to the oil phase solvent is 20-40g/100mL; the mass ratio of the emulsifier to the water is 0.35-0.5:200; The mass ratio of the oil phase to the water phase is 1:2-4.
  8. 8. The process according to claim 1, wherein in step 3), The mass ratio of the water glass solution to the phase-change microcapsule is 5-15:1; the mass ratio of the water glass to the solvent in the water glass solution is 1:2.5-3.5.
  9. 9. The method according to claim 1, wherein in the step 4), the freeze-drying is performed by pre-freezing at-45 ℃ to-35 ℃ for 1-2 hours and further freeze-drying at 0-5Pa, -20 ℃ to-15 ℃ for 40-60 hours.
  10. 10. The process according to claim 1 or 9, wherein in step 4), The overall thickness of the silicon-based aerogel composite phase-change material heat insulation felt is 0.6-2.2mm; the thickness of the heat insulation base material is 0.5-2mm.

Description

Preparation method of silicon-based aerogel composite phase-change material heat insulation felt Technical Field The invention relates to the field of composite materials, in particular to a preparation method of a silicon-based aerogel composite phase-change material heat insulation felt. Background Under the background of rapid development of new energy, the heat insulation materials among the battery cells relate to the safe operation of the pack module, and the heat insulation materials can obstruct heat transfer when the battery cells are in thermal runaway, so that the thermal runaway is prevented from spreading. The heat insulation material which is commonly used at present is an aerogel material, and has extremely low heat conductivity coefficient (the normal temperature heat conductivity coefficient is less than or equal to 0.016W/(m.K)), so that heat transmission can be blocked when the battery core is in thermal runaway, but the dissipation of the heat of the battery core which is out of control is also blocked, and the negative effect of heat accumulation in the battery core package is caused. Phase change materials are another potential new type of insulating material that can absorb heat at high temperatures through the phase change process, lowering the temperature of the battery pack system and thus blocking thermal runaway propagation. However, the disadvantage of the phase change material that liquid leakage is liable to occur limits its application in battery thermal management. Thus, combining aerogel and phase change material, by virtue of the ultra high porosity (> 90%), low density and large specific surface area of aerogel, can provide packaging support and more loading for the phase change material. For example, patent CN119490824a discloses a thermal insulation material that supports a phase change material in a cellulose aerogel. The aerogel is used for isolating heat and the phase change material is used for absorbing waste heat, so that the whole heat insulation performance is expected to be superior to that of the single aerogel. However, the high thermal conductivity properties (such as paraffin, usually about 0.15-0.25W/(m.k)) and the low thermal conductivity properties of aerogel of the phase change material are contradictory, and the aerogel is simply used as a carrier, for example, the phase change material solution is immersed in the aerogel, and the phase change material is loaded by using the porous structure of the aerogel, so that the phase change material is filled in the pores of the aerogel, on one hand, the phase change material has poor compatibility with the aerogel, the loading amount is small, the phase change material leaks when the phase change is melted, and on the other hand, the phase change material is directly contacted with the aerogel, so that the low thermal conductivity properties of the aerogel can be damaged, and particularly, the high-temperature heat insulation performance of the aerogel can be seriously affected after the phase change material is melted at a high temperature, so that the advantages of the two cannot be fully exerted. Disclosure of Invention In order to solve the technical problems, the invention provides a preparation method of a silicon-based aerogel composite phase-change material heat insulation felt. In the heat insulation felt prepared by the method, the phase change material paraffin has good interfacial compatibility with the silicon-based aerogel, the paraffin is not easy to leak, and the negative influence of the high-heat-conductivity coefficient paraffin on the heat insulation performance of the silicon-based aerogel with low heat-conductivity coefficient is avoided, so that the silicon-based aerogel composite phase change material heat insulation felt still has excellent heat insulation effect at high temperature. The specific technical scheme of the invention comprises a preparation method of the silicon-based aerogel composite phase-change material heat insulation felt, which comprises the following steps: 1) Dispersing N-isopropyl acrylamide, a hydrophobic monomer and a cross-linking agent in water to obtain a pre-reaction liquid. 2) Mixing paraffin emulsion with pre-reaction liquid, performing interfacial polymerization reaction under the action of an initiator, purifying, and freeze-drying to obtain the phase-change microcapsule taking paraffin as a core material and N-isopropyl acrylamide and hydrophobic monomer copolymer as a cross-linked shell. 3) Adding phase-change microcapsules at the temperature of less than or equal to 25 ℃ to disperse uniformly, and adjusting the pH value to be less than or equal to 5-6 to obtain silica sol loaded with the phase-change microcapsules; 4) Soaking the heat-insulating base material in silica sol loaded with phase-change microcapsules at the temperature of less than or equal to 25 ℃, and aging and freeze-drying to obtain the silicon-based aerogel composite phase-change mate