An intumescent solvent-free aerogel fireproof coating for energy storage cabinets and a preparation method thereof

Abstract

The application provides an intumescent solvent-free aerogel fireproof coating for an energy storage cabinet and a preparation method thereof, and relates to the technical field of coatings.The intumescent solvent-free aerogel fireproof coating comprises the following raw materials in parts by weight: 50-60 parts of epoxy resin, 5-10 parts of SiO2 aerogel, 5-10 parts of modified sodium alginate aerogel, 0.8-1.5 parts of nano-TiO2, 1-3 parts of alkyl acid grafted cellulose nanocrystals, 5-10 parts of ammonium polyphosphate, 4-6 parts of melamine, 26-40 parts of a curing agent, 0.3-0.5 parts of a leveling agent and 0.2-0.4 parts of a defoaming agent.The solvent-free aerogel fireproof coating has excellent fireproof performance, and when a fire occurs, the coating rapidly expands to form a dense carbonized layer with a thickness of more than 25 times, which not only blocks heat radiation, but also absorbs flame energy to delay the spread of the fire, thereby ensuring that the cabinet structure does not collapse and is not burned through in a fire.The application does not need external driving such as electricity and gas, and only realizes fireproofing through the physical properties of the material, is suitable for unattended energy storage scenarios, and provides a golden time for fire fighting disposal.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to an intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets and its preparation method. Background Technology

[0002] With the large-scale development of the new energy storage industry, energy storage cabinets (including containerized energy storage cabinets and pack modules) have become the core carriers of power peak shaving and distributed energy systems. However, thermal runaway fires caused by battery module short circuits and overloads have become a key bottleneck restricting the safe operation of the industry. Currently, energy storage cabinet fire prevention faces the following challenges: 1. Risk of thermal runaway propagation: A chain reaction crisis at 1000℃. For example, if the battery modules (such as lithium batteries) inside the energy storage cabinet are overcharged, short-circuited, or have failed thermal management, the temperature can instantly soar to over 1000℃. Thermal runaway is characterized by rapid outbreak and wide spread. After a single module catches fire, the heat conduction speed can reach 0.8~1.2℃ / S, and it can spread to adjacent modules within 3~5 minutes, causing a fire in the entire cabinet. Traditional thermal insulation boards (such as rock wool and glass wool) will soften and fail at temperatures above 800℃, failing to block heat radiation and heat conduction, making it difficult to curb the "domino effect". 2. Traditional protection solutions have shortcomings such as incomplete coverage and poor adaptability: Existing fire protection solutions for energy storage cabinets mainly rely on "rigid plate splicing". The plates need to be cut to fit the cabinet structure, and heat leakage channels can easily form at the joints. The coverage rate of complex parts such as curved surfaces and corners of the pack module is less than 60%. The construction is complicated, requiring custom molds and on-site splicing and fixing, and disassembly is difficult during later maintenance. The VOC (volatile organic compound) content of traditional solvent-based coatings is as high as 200~400g / L, which does not meet the environmental protection standards for indoor energy storage stations, and there are safety hazards during construction.

[0003] Therefore, it is necessary to develop a fire-retardant coating for energy storage cabinets that can effectively block heat conduction when a fire occurs, prevent the thermal runaway of a single module from spreading to the entire cabinet and other cabinets, provide the golden time for fire fighting, and be suitable for unattended energy storage scenarios. Summary of the Invention

[0004] Therefore, this invention proposes an intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets and its preparation method.

[0005] The technical solution of this invention is implemented as follows: An intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets comprises, by weight, the following raw materials: 50-60 parts epoxy resin, 5-10 parts SiO2 aerogel, 5-10 parts modified sodium alginate aerogel, 0.8-1.5 parts nano TiO2, 1-3 parts alkyl acid grafted cellulose nanocrystals, 5-10 parts ammonium polyphosphate, 4-6 parts melamine, 26-40 parts curing agent, 0.3-0.5 parts leveling agent, and 0.2-0.4 parts defoamer.

[0006] Furthermore, the preparation method of the modified sodium alginate aerogel includes: Sodium alginate solution and tin tetrachloride were mixed, ultrasonicated, filtered, frozen, and freeze-dried to obtain an intermediate product. The intermediate product was then calcined to obtain modified sodium alginate aerogel.

[0007] Furthermore, the mass concentration of the sodium alginate solution is 30%-50%; the solid-liquid ratio of the tin tetrachloride to the sodium alginate solution is 1:10-20 g / mL.

[0008] Furthermore, the ultrasonic treatment is performed at 25-35 kHz, 200-300 rpm, and 20-25°C for 10-12 hours; the calcination is performed at 650-750°C for 1-2 hours in a mixed atmosphere of 95% nitrogen and 5% oxygen.

[0009] Furthermore, the preparation method of the alkyl acid-grafted cellulose nanocrystals includes: Cellulose nanocrystals were added to N,N-dimethylformamide, followed by the addition of octanoic acid and p-toluenesulfonic acid. The mixture was then magnetically stirred, washed by centrifugation, and dried under vacuum to obtain alkyl acid-grafted cellulose nanocrystals.

[0010] Furthermore, the cellulose nanocrystals have a diameter of 10-20 nm and a length of 100-200 nm; the solid-liquid ratio of the cellulose nanocrystals to N,N-dimethylformamide is 1:8-10 g / mL; the mass ratio of the cellulose nanocrystals to octanoic acid and p-toluenesulfonic acid is 1:2-4:0.08-0.1; and the reaction temperature is 80-90℃, and the reaction time is 4-8 h.

[0011] Cellulose nanocrystals are a novel nanomaterial prepared from cellulose molecules through a special process. Cellulose nanocrystals possess the following characteristics: 1. Nanoscale size: Cellulose nanocrystals are typically in the nanometer range, exhibiting high specific surface area and unique physicochemical properties. 2. High strength: Cellulose nanocrystals possess excellent mechanical properties, with strength reaching or exceeding that of steel, making them a high-strength nanomaterial. 3. Biodegradability: Based on natural cellulose, cellulose nanocrystals exhibit good biodegradability and are environmentally friendly. 4. Tunable: By controlling the preparation methods and processing conditions, the morphology, structure, and properties of cellulose nanocrystals can be adjusted to meet the needs of different applications.

[0012] Furthermore, the curing agent is triethylenetetramine, the leveling agent is an organosilicon leveling agent, and the defoamer is polydimethylsiloxane.

[0013] A method for preparing an intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets, comprising the following steps: Epoxy resin, ammonium polyphosphate and melamine, SiO2 aerogel, modified sodium alginate aerogel, nano TiO2, alkyl acid grafted cellulose nanocrystals, leveling agent and defoamer are mixed and stirred, and then a curing agent is added and stirred to obtain an intumescent solvent-free aerogel fireproof coating.

[0014] Furthermore, the mixing speed is 1000-1200 rpm and the time is 50-70 min; the addition of the curing agent and stirring is carried out at 200-300 rpm for 5-8 min.

[0015] Application of an intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets in fire protection of energy storage cabinets.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The solvent-free aerogel fire-retardant coating of this invention is VOC-free, environmentally friendly, and possesses excellent fire-retardant performance. Through a double insulation process of expanded carbon layer and aerogel, it effectively blocks heat conduction, preventing the thermal runaway of a single module from spreading to the entire cabinet and other cabinets. In the event of a fire, the coating rapidly expands to form a dense carbonized layer more than 25 times its original thickness, which not only blocks heat radiation but also absorbs flame energy, delaying the spread of fire and ensuring that the cabinet structure does not collapse or burn through during a fire. This invention requires no external driving force such as electricity or gas; it achieves fire resistance solely through the physical properties of the material, making it suitable for unattended energy storage scenarios and providing crucial time for firefighting.

[0017] 2. The modified sodium alginate aerogel of the present invention uses Sn-doped carbon framework to maintain structural stability at high temperatures, prevent carbon layer collapse, and synergize with SiO2 aerogel to improve structural stability and enhance compatibility with other components of the coating. The alkyl acid-grafted cellulose nanocrystals of the present invention are grafted with n-octanoic acid, while retaining the hydroxyl groups of cellulose nanocrystals, which improves interfacial compatibility, enhances the bonding force between the aerogel and epoxy resin, achieves uniform dispersion of components, and improves density.

[0018] 3. The SnO2 in the modified sodium alginate aerogel of the present invention can promote the early cross-linking of epoxy resin and alkyl acid grafted cellulose nanocrystals into carbon, resulting in a denser carbon layer; the synergistic effect of SnO2 and nano TiO2 in the modified sodium alginate aerogel can reduce the concentration and toxicity of smoke during fires.

[0019] 4. The solvent-free aerogel fireproof coating of the present invention has high strength, high toughness, no risk of cracking, and is dense after charring, and is resistant to jet fire.

[0020] 5. The solvent-free aerogel fire-retardant coating of this invention can achieve full protective coverage, is flexible in construction, and supports multiple methods such as spraying, brushing, and roller coating. It can be directly adhered to the energy storage cabinet body, the curved surfaces, corners, and seams of the pack module, with no blind spots for cutting. It is structurally adaptable, and the coating thickness (typically 5-8mm) can be flexibly adjusted according to the specifications of the energy storage cabinet (such as 20-foot or 40-foot container cabinets). Detailed Implementation

[0021] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0022] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0023] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0024] The curing agent of this invention is triethylenetetramine, the leveling agent is an organosilicon leveling agent, and the defoamer is polydimethylsiloxane.

[0025] Preparation Example 1 The preparation methods of modified sodium alginate aerogel include: Tin tetrachloride and 40wt% sodium alginate solution were mixed at a solid-liquid ratio of 1:15 g / mL and ultrasonicated at 30 kHz, 250 rpm, and 23 °C for 12 h. The mixture was then filtered, frozen, and freeze-dried. The resulting product was calcined at 700 °C for 2 h in a mixed atmosphere of 95% N2 and 5% O2 to obtain modified sodium alginate aerogel.

[0026] Preparation Example 2 Methods for preparing alkyl acid-grafted cellulose nanocrystals include: Cellulose nanocrystals (20 nm in diameter and 100 nm in length) were added to N,N-dimethylformamide at a solid-liquid ratio of 1:10 g / mL. Octanoic acid and p-toluenesulfonic acid were also added. The mass ratio of cellulose nanocrystals to octanoic acid and p-toluenesulfonic acid was 1:3:0.08. The mixture was magnetically stirred at 85 °C for 6 h, centrifuged, washed, and vacuum dried to obtain alkyl acid-grafted cellulose nanocrystals.

[0027] Example 1 An intumescent solvent-free aerogel fireproof coating for energy storage cabinets comprises the following raw materials by weight: 55 parts epoxy resin, 8 parts SiO2 aerogel, 8 parts modified sodium alginate aerogel, 1 part nano TiO2, 2 parts alkyl acid grafted cellulose nanocrystals, 8 parts ammonium polyphosphate, 5 parts melamine, 35 parts curing agent, 0.4 parts leveling agent, and 0.3 parts defoamer.

[0028] The preparation method of the above-mentioned intumescent solvent-free aerogel fire-retardant coating includes the following specific steps: Epoxy resin, ammonium polyphosphate and melamine, SiO2 aerogel, modified sodium alginate aerogel, nano TiO2, alkyl acid grafted cellulose nanocrystals, leveling agent and defoamer were mixed and stirred at 1100 rpm for 60 min. Then, curing agent was added and stirred at 250 rpm for 7 min to obtain an intumescent solvent-free aerogel fireproof coating.

[0029] Example 2 An intumescent solvent-free aerogel fireproof coating for energy storage cabinets comprises the following raw materials by weight: 50 parts epoxy resin, 5 parts SiO2 aerogel, 5 parts modified sodium alginate aerogel, 0.8 parts nano TiO2, 1 part alkyl acid grafted cellulose nanocrystals, 5 parts ammonium polyphosphate, 4 parts melamine, 28.5 parts curing agent, 0.3 parts leveling agent, and 0.2 parts defoamer.

[0030] The preparation method of the above-mentioned intumescent solvent-free aerogel fire-retardant coating includes the following specific steps: Epoxy resin, ammonium polyphosphate and melamine, SiO2 aerogel, modified sodium alginate aerogel, nano TiO2, alkyl acid grafted cellulose nanocrystals, leveling agent and defoamer are mixed and stirred at 1000 rpm for 50 min. Then, curing agent is added and stirred at 200 rpm for 5 min to obtain an intumescent solvent-free aerogel fireproof coating.

[0031] Example 3 An intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets comprises, by weight, the following raw materials: 60 parts epoxy resin, 10 parts SiO2 aerogel, 10 parts modified sodium alginate aerogel, 1.5 parts nano TiO2, 3 parts alkyl acid grafted cellulose nanocrystals, 10 parts ammonium polyphosphate, 6 parts melamine, 40.5 parts curing agent, 0.5 parts leveling agent, and 0.4 parts defoamer.

[0032] The preparation method of the above-mentioned intumescent solvent-free aerogel fire-retardant coating includes the following specific steps: Epoxy resin, ammonium polyphosphate and melamine, SiO2 aerogel, modified sodium alginate aerogel, nano TiO2, alkyl acid grafted cellulose nanocrystals, leveling agent and defoamer were mixed and stirred at 1200 rpm for 70 min. Then, curing agent was added and stirred at 300 rpm for 8 min to obtain an intumescent solvent-free aerogel fireproof coating.

[0033] Comparative Example 1 The difference from Example 1 is that the modified sodium alginate aerogel is missing, and the curing agent is adjusted to 32 parts. Otherwise, it is the same as Example 1.

[0034] Comparative Example 2 The difference from Example 1 is that alkyl acid-grafted cellulose nanocrystals are replaced with cellulose nanocrystals, while the rest is the same as Example 1.

[0035] Test Example 1 Table 1 shows the maximum foaming ratio and foaming time of the intumescent solvent-free aerogel fire-retardant coatings of Examples 1-3 and Comparative Examples 1-2. A higher maximum foaming ratio indicates better fire-retardant and heat-insulating effects. A shorter foaming time indicates faster reaction and better fire-retardant and heat-insulating effects.

[0036] Table 1

[0037] As can be seen from the maximum foaming ratio and foaming time in Table 1, the coatings of Examples 1-3 have a high maximum foaming ratio, faster foaming time, faster reaction, thicker foam layer, and better fireproof and heat insulation effect.

[0038] Test Example 2 Other performance indicators of the intumescent solvent-free aerogel fire retardant coatings of Examples 1-3 and Comparative Examples 1-2 were tested. The technical indicators and test results are shown in Tables 2-3.

[0039] Table 2

[0040] Table 3

[0041] As can be seen from Table 3, the intumescent solvent-free aerogel fire retardant coatings prepared in Examples 1-3 of the present invention have excellent performance indicators. Most importantly, after the above tests, the heat insulation efficiency of the intumescent solvent-free aerogel fire retardant coatings in Examples 1-3 did not decrease significantly.

[0042] Test Example 3 A simulated hydrocarbon fire in an energy storage cabinet was conducted, and the fire resistance performance of the intumescent solvent-free aerogel fire retardant coating of Example 1 was tested in a closed environment by spraying flames at 1100°C.

[0043] The results are shown in Table 4.

[0044] Table 4

[0045] As can be seen from Table 4, a coating with a thickness of only 8 mm can meet the requirement of burning for 90 minutes in a closed environment with a jet flame of 1100℃, with a surface temperature ≤300℃.

[0046] The intumescent solvent-free aerogel fire-retardant coating of the present invention can withstand continuous combustion at 1100°C for 3 hours on the fire-facing surface, while the temperature of the cold surface is stably controlled within 220°C (far below the 400°C tolerance limit of battery modules and components).

[0047] Test Example 4 The fire resistance performance of the intumescent solvent-free aerogel fire retardant coating of Example 1 on steel trusses at different thicknesses was statistically analyzed.

[0048] The results are shown in Table 5.

[0049] Table 5

[0050] As can be seen from Table 5, the intumescent solvent-free aerogel fire retardant coating prepared in Example 1 of the present invention has excellent fire retardant performance and is suitable for application on complex structural surfaces, such as steel trusses.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets, characterized in that, The following raw materials are included by weight: 50-60 parts epoxy resin, 5-10 parts SiO2 aerogel, 5-10 parts modified sodium alginate aerogel, 0.8-1.5 parts nano TiO2, 1-3 parts alkyl acid grafted cellulose nanocrystals, 5-10 parts ammonium polyphosphate, 4-6 parts melamine, 26-40 parts curing agent, 0.3-0.5 parts leveling agent, and 0.2-0.4 parts defoamer.

2. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 1, characterized in that, The preparation method of the modified sodium alginate aerogel includes: Sodium alginate solution and tin tetrachloride were mixed, ultrasonicated, filtered, frozen, and freeze-dried to obtain an intermediate product. The intermediate product was then calcined to obtain modified sodium alginate aerogel.

3. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 2, characterized in that, The mass concentration of the sodium alginate solution is 30%-50%; the solid-liquid ratio of the tin tetrachloride to the sodium alginate solution is 1:10-20 (g / mL).

4. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 2, characterized in that, The ultrasonic treatment is performed at 25-35 kHz, 200-300 rpm, and 20-25°C for 10-12 hours; the calcination is performed at 650-750°C for 1-2 hours in a mixed atmosphere of 95% nitrogen and 5% oxygen.

5. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 1, characterized in that, The preparation method of the alkyl acid-grafted cellulose nanocrystals includes: Cellulose nanocrystals were added to N,N-dimethylformamide, followed by the addition of octanoic acid and p-toluenesulfonic acid. The mixture was then magnetically stirred, washed by centrifugation, and dried under vacuum to obtain alkyl acid-grafted cellulose nanocrystals.

6. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 5, characterized in that, The cellulose nanocrystals have a diameter of 10-20 nm and a length of 100-200 nm; the solid-liquid ratio of the cellulose nanocrystals to N,N-dimethylformamide is 1:8-10 g / mL; the mass ratio of the cellulose nanocrystals to octanoic acid and p-toluenesulfonic acid is 1:2-4:0.08-0.1; the reaction temperature is 80-90℃ and the reaction time is 4-8 h.

7. The intumescent solvent-free aerogel fire-retardant coating for energy storage cabinets as described in claim 1, characterized in that, The curing agent is triethylenetetramine, the leveling agent is an organosilicon leveling agent, and the defoamer is polydimethylsiloxane.

8. The method for preparing the intumescent solvent-free aerogel fire-retardant coating according to any one of claims 1-7, characterized in that, The specific steps include: Epoxy resin, ammonium polyphosphate and melamine, SiO2 aerogel, modified sodium alginate aerogel, nano TiO2, alkyl acid grafted cellulose nanocrystals, leveling agent and defoamer are mixed and stirred, and then a curing agent is added and stirred to obtain an intumescent solvent-free aerogel fireproof coating.

9. The method for preparing an intumescent solvent-free aerogel fire-retardant coating for an energy storage cabinet as described in claim 8, characterized in that, The mixing speed is 1000-1200 rpm and the time is 50-70 min; the addition of the curing agent and stirring is carried out at 200-300 rpm for 5-8 min.

10. The application of the intumescent solvent-free aerogel fire-retardant coating according to any one of claims 1-7 in the fire protection of energy storage cabinets.

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