Insulating varnish for new energy vehicle battery pack and preparation method thereof

Abstract

The invention discloses an insulating varnish for a new energy vehicle battery pack and a preparation method thereof, relating to the technical field of insulating coatings. The insulating varnish is prepared from the following raw materials, measured by weight: 30-40 parts of a vinyl-containing hyperbranched polysiloxane, 15-20 parts of a functional film-forming copolymer, 20-30 parts of a filler, 1-3 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 2-4 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1-3 parts of 2,4,6-trivinylboroxine, 1-3 parts of bicyclo[2.2.1]heptanedimethylamine, 0.4-0.8 parts of a photoinitiator, 1-3 parts of an auxiliary agent, and 30-40 parts of a solvent. The insulating varnish has good insulation, strong adhesion to substrates, excellent resistance to high and low temperature cycling, and sufficient toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating coatings, and in particular to an insulating varnish for a new energy vehicle battery pack and a preparation method thereof. Background Art

[0002] As the global energy crisis deepens, oil resources become increasingly depleted, and the impact of air pollution and rising global temperatures intensifies, governments and automakers worldwide are recognizing that energy conservation and emission reduction are key priorities for future automotive technology development. The vigorous development of new energy vehicles has been elevated to a strategic position in countries around the world. New energy electric vehicles, the most common type of new energy vehicle, offer advantages over traditional vehicles such as smooth operation, quiet operation, zero pollution, low carbon emissions, and enhanced safety, offering broad market prospects.

[0003] The battery pack is the core energy source of new energy electric vehicles, providing the driving power for the entire vehicle. Its reliability and stability directly impact the driving safety and normal operating stability of new energy electric vehicles. To improve the reliability and stability of battery packs, insulating varnishes are widely used in new energy battery packs. Insulating varnishes protect battery components from mechanical damage and chemical corrosion, extending their service life, improving operational safety, and preventing failures caused by short circuits and breakdown, thereby ensuring the proper operation of the battery. However, existing insulating varnishes often suffer from technical drawbacks such as limited insulation performance, poor adhesion to substrates, poor resistance to high and low temperature cycling, insufficient mechanical properties, low toughness, and susceptibility to cracking.

[0004] To address the above-mentioned problems, a Chinese invention patent with authorization publication number CN104592813B discloses a method for preparing an insulating varnish, wherein the preparation method comprises mixing cellulose nitrate, an amino-modified alkyd resin, an epoxy resin, styrene, a curing agent, and a film-forming agent; with respect to 100 parts by weight of the cellulose nitrate, the amount of the amino-modified alkyd resin is 20-50 parts by weight, the amount of the epoxy resin is 20-50 parts by weight, the amount of the styrene is 30-80 parts by weight, the amount of the curing agent is 1-5 parts by weight, and the amount of the film-forming agent is 1-5 parts by weight. The invention also discloses an insulating varnish prepared by the above-mentioned method. By using cellulose nitrate as the basic film-forming substance, adding an alkyd resin and an epoxy resin modified with an amino resin, and combining styrene as a reactive diluent, the insulating varnish achieves high toughness and good quick-drying properties. However, the high and low temperature cycling resistance and mechanical properties of the insulating varnish still need to be further improved.

[0005] It can be seen that it is particularly important to develop an insulating varnish for new energy vehicle battery packs with good insulation, strong adhesion to the substrate, good resistance to high and low temperature cycling, and sufficient toughness, and a preparation method thereof. Summary of the Invention

[0006] The main purpose of the present invention is to provide an insulating varnish for new energy vehicle battery packs with good insulation, strong adhesion to the substrate, good resistance to high and low temperature cycles, and sufficient toughness, and a preparation method thereof.

[0007] To achieve the above objectives, the present invention provides an insulating varnish for a new energy vehicle battery pack, which is prepared from the following raw materials in parts by weight: 30-40 parts of a vinyl-containing hyperbranched polysiloxane, 15-20 parts of a functional film-forming copolymer, 20-30 parts of a filler, 1-3 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 2-4 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1-3 parts of 2,4,6-trivinylcycloboroxine, 1-3 parts of bicyclo[2.2.1]heptanedimethylamine, 0.4-0.8 parts of a photoinitiator, 1-3 parts of an auxiliary agent, and 30-40 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propen-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0008] Preferably, the solvent is at least one of ethylene glycol ethyl ether acetate, acetone, and propylene glycol methyl ether.

[0009] Preferably, the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:(0.8-1.2):(1-1.5).

[0010] Preferably, the defoaming agent is one or more of tributyl phosphate, defoaming agent Deqian 3100, and defoaming agent BYK088; the leveling agent is at least one of German BYK leveling agent BYK-333 and silicone leveling agent HY-5030; and the dispersant is at least one of polycarboxylate dispersant 5040 and sodium hexametaphosphate.

[0011] Preferably, the photoinitiator is at least one of benzoin ethyl ether, 2,4-dihydroxybenzophenone and benzoin.

[0012] Preferably, the filler is at least one of silicon micropowder, mica powder, double fly ash, and titanium dioxide; and the particle size of the filler is 800-1200 mesh.

[0013] Preferably, the preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsilane, and azobisisobutyronitrile to a high-boiling point solvent, stirring and reacting at 60-70°C in a nitrogen atmosphere for 4-6 hours, cooling to room temperature after the reaction, precipitating in water, then washing the precipitated polymer with ethanol 3-6 times, and finally drying in a vacuum drying oven at 85-95°C to constant weight.

[0014] Preferably, the mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsilane, azobisisobutyronitrile, and high boiling point solvent is 1:(0.8-1.2):(0.1-0.3):0.2:(0.02-0.04):(8-15); the high boiling point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0015] Furthermore, there is no special requirement for the source of the vinyl-containing hyperbranched polysiloxane. In one embodiment of the present invention, the vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization publication number CN102276836B.

[0016] Another object of the present invention is to provide a method for preparing the insulating varnish for the new energy vehicle battery pack, comprising the following steps: mixing the raw materials uniformly by weight to obtain the insulating varnish for the new energy vehicle battery pack.

[0017] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0018] (1) The method for preparing the insulating varnish for new energy vehicle battery pack disclosed in the present invention only requires uniform mixing of the raw materials by weight, without the need for special equipment, low energy consumption and labor intensity, high preparation efficiency and finished product qualification rate, and is suitable for continuous large-scale production.

[0019] (2) The insulating varnish for new energy vehicle battery pack disclosed in the present invention is made of the following raw materials in parts by weight: 30-40 parts of vinyl-containing hyperbranched polysiloxane, 15-20 parts of functional film-forming copolymer, 20-30 parts of filler, 1-3 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 2-4 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1-3 parts of 2,4,6-trivinylcycloboroxane, 1-3 parts of bicyclo[2.2.1]heptanedimethylamine, 0.4-0.8 parts of photoinitiator, 1-3 parts of auxiliary agent, and 30-40 parts of solvent; through the mutual coordination and joint action of the raw materials, the insulating varnish prepared has good insulation, strong adhesion to the substrate, good resistance to high and low temperature cycling, and sufficient toughness.

[0020] (3) The present invention discloses an insulating varnish for new energy vehicle battery packs, wherein the functional film-forming copolymer is prepared by free radical copolymerization of allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane. The introduced succinimidyl carbonate, epoxy group, ester group, quinoxalinone group, and siloxane group, under the multiple effects of electronic effect, steric effect, and conjugation effect, not only give the product excellent insulation performance, but also improve high and low temperature cycling performance and toughness; the addition of vinyl-containing hyperbranched polysiloxane, in combination with other raw materials, not only improves the insulation performance and high and low temperature cycling performance, but also improves the toughness of the paint film.

[0021] (4) The insulating varnish for new energy vehicle battery pack disclosed in the present invention has components containing unsaturated olefinic bonds in the raw materials that undergo photocuring under the action of a photoinitiator, and components containing amino groups can also undergo epoxy ring-opening reaction with epoxy groups in the functional film-forming copolymer, while introducing multiple interpenetrating network structures into the paint film structure, which can effectively improve the insulation properties, high and low temperature cycle resistance and toughness of the insulating varnish, thereby extending its service life.

[0022] (5) The insulating varnish for new energy vehicle battery pack disclosed in the present invention, through the reasonable selection of raw materials and content ratio, the groups on the functional film-forming copolymer will also interact with the introduced hyperbranched polysiloxane, bicyclo[2.2.1]heptyl, cycloboroxine, and triazine to further improve the insulation properties, high and low temperature cycle resistance and toughness of the insulating varnish, thereby extending its service life. DETAILED DESCRIPTION

[0023] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations. Example 1

[0024] An insulating varnish for a new energy vehicle battery pack is prepared from the following raw materials in parts by weight: 30 parts of a vinyl-containing hyperbranched polysiloxane, 15 parts of a functional film-forming copolymer, 20 parts of a filler, 1 part of 5-vinylbicyclo[2.2.1]hept-2-ene, 2 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1 part of 2,4,6-trivinylcycloboroxine, 1 part of bicyclo[2.2.1]heptanedimethylamine, 0.4 parts of a photoinitiator, 1 part of an auxiliary agent, and 30 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0025] The solvent is ethylene glycol ethyl ether acetate; the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:0.8:1; the defoamer is tributyl phosphate; the leveling agent is German BYK leveling agent BYK-333; the dispersant is polycarboxylate dispersant 5040; the photoinitiator is benzoin ethyl ether; the filler is silicon micropowder; and the particle size of the filler is 800 mesh.

[0026] The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 60°C in a nitrogen atmosphere for 4 hours, cooling to room temperature after the reaction, precipitating in water, then washing the precipitated polymer with ethanol three times, and finally drying in a vacuum drying oven at 85°C to constant weight; the mass ratio of allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, azobisisobutyronitrile, and high-boiling-point solvent is 1:0.8:0.1:0.2:0.02:8; the high-boiling-point solvent is dimethyl sulfoxide. GPC test shows that the M of the copolymer is 0.8:0.1:0.2:0.02:8. n =13517g / mol,M W / M n =1.239; EDX elemental quantitative analysis confirmed that the mass ratio of the structural units introduced into the copolymer by allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propen-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane, respectively, was 0.98:0.79:0.1:0.19.

[0027] The vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN102276836B.

[0028] A preparation method of the insulating varnish for the new energy vehicle battery pack comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain the insulating varnish for the new energy vehicle battery pack. Example 2

[0029] An insulating varnish for a new energy vehicle battery pack is prepared from the following raw materials in parts by weight: 32 parts of a vinyl-containing hyperbranched polysiloxane, 17 parts of a functional film-forming copolymer, 23 parts of a filler, 1.5 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 2.5 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1.5 parts of 2,4,6-trivinylcycloboroxine, 1.5 parts of bicyclo[2.2.1]heptanedimethylamine, 0.5 parts of a photoinitiator, 1.5 parts of an auxiliary agent, and 32 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0030] The solvent is acetone; the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:0.9:1.2; the defoamer is defoamer Deqian 3100; the leveling agent is an organosilicon leveling agent HY-5030; the dispersant is sodium hexametaphosphate; the photoinitiator is 2,4-dihydroxybenzophenone; the filler is mica powder; and the particle size of the filler is 900 mesh.

[0031] The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 63°C in a nitrogen atmosphere for 4.5 hours, cooling to room temperature after the reaction, precipitating in water, washing the precipitated polymer four times with ethanol, and finally drying in a vacuum drying oven at 88°C to constant weight; the mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, azobisisobutyronitrile, and the high-boiling-point solvent is 1:0.9:0.15:0.2:0.025:10; and the high-boiling-point solvent is N,N-dimethylformamide.

[0032] The vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN102276836B.

[0033] A preparation method of the insulating varnish for the new energy vehicle battery pack comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain the insulating varnish for the new energy vehicle battery pack. Example 3

[0034] An insulating varnish for a new energy vehicle battery pack is prepared from the following raw materials in parts by weight: 35 parts of a vinyl-containing hyperbranched polysiloxane, 18 parts of a functional film-forming copolymer, 25 parts of a filler, 2 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 3 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 2 parts of 2,4,6-trivinylcycloboroxine, 2 parts of bicyclo[2.2.1]heptanedimethylamine, 0.6 parts of a photoinitiator, 2 parts of an auxiliary agent, and 35 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0035] The solvent is propylene glycol methyl ether; the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:1:1.3; the defoamer is defoamer BYK088; the leveling agent is German BYK leveling agent BYK-333; the dispersant is polycarboxylate dispersant 5040; the photoinitiator is benzoin; the filler is double fly ash; and the particle size of the filler is 1000 mesh.

[0036] The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 65°C in a nitrogen atmosphere for 5 hours, cooling to room temperature after the reaction, precipitating in water, washing the precipitated polymer with ethanol 5 times, and finally drying in a vacuum drying oven at 90°C to constant weight; the mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, azobisisobutyronitrile, and the high-boiling-point solvent is 1:1:0.2:0.2:0.03:12; and the high-boiling-point solvent is N-methylpyrrolidone.

[0037] The vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN102276836B.

[0038] A preparation method of the insulating varnish for the new energy vehicle battery pack comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain the insulating varnish for the new energy vehicle battery pack. Example 4

[0039] An insulating varnish for a new energy vehicle battery pack is prepared from the following raw materials in parts by weight: 38 parts of a vinyl-containing hyperbranched polysiloxane, 19 parts of a functional film-forming copolymer, 28 parts of a filler, 2.5 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 3.5 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 2.5 parts of 2,4,6-trivinylcycloboroxine, 2.5 parts of bicyclo[2.2.1]heptanedimethylamine, 0.7 part of a photoinitiator, 2.5 parts of an auxiliary agent, and 38 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0040] The solvent is ethylene glycol ethyl ether acetate; the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:1.1:1.4; the defoamer is a mixture of tributyl phosphate, defoamer Deqian 3100, and defoamer BYK088 in a mass ratio of 1:2:3; the leveling agent is a mixture of German BYK leveling agent BYK-333 and silicone leveling agent HY-5030 in a mass ratio of 3:5; the dispersant is a mixture of polycarboxylate dispersant 5040 and sodium hexametaphosphate in a mass ratio of 1:3; the photoinitiator is a mixture of benzoin ethyl ether, 2,4-dihydroxybenzophenone, and benzoin in a mass ratio of 1:3:2; the filler is a mixture of silicon micropowder, mica powder, double fly ash, and titanium dioxide in a mass ratio of 1:1:3:5; and the particle size of the filler is 1100 mesh.

[0041] The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsilane, and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 68° C. in a nitrogen atmosphere for 5.5 hours, cooling to room temperature after the reaction, precipitating in water, washing the precipitated polymer with ethanol 5 times, and finally placing in a vacuum drying oven for 9 hours. Dry to constant weight at 3°C; the mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propen-1-yl)-2(1H)-quinoxalinone, methylvinylsilane, azobisisobutyronitrile, and high boiling point solvent is 1:1.1:0.25:0.2:0.035:14; the high boiling point solvent is a mixture of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone in a mass ratio of 1:3:5.

[0042] The vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN102276836B.

[0043] A preparation method of the insulating varnish for the new energy vehicle battery pack comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain the insulating varnish for the new energy vehicle battery pack. Example 5

[0044] An insulating varnish for a new energy vehicle battery pack is prepared from the following raw materials in parts by weight: 40 parts of a vinyl-containing hyperbranched polysiloxane, 20 parts of a functional film-forming copolymer, 30 parts of a filler, 3 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 4 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 3 parts of 2,4,6-trivinylcycloboroxine, 3 parts of bicyclo[2.2.1]heptanedimethylamine, 0.8 parts of a photoinitiator, 3 parts of an auxiliary agent, and 40 parts of a solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, and methylvinylsiloxane through free radical copolymerization.

[0045] The solvent is ethylene glycol ethyl ether acetate; the auxiliary agent is a mixture of a defoamer, a leveling agent, and a dispersant in a mass ratio of 1:1.2:1.5; the defoamer is tributyl phosphate; the leveling agent is an organosilicon leveling agent HY-5030; the dispersant is a polycarboxylate dispersant 5040; the photoinitiator is benzoin ethyl ether; the filler is titanium dioxide; and the particle size of the filler is 1200 mesh.

[0046] The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 70°C in a nitrogen atmosphere for 6 hours, cooling to room temperature after the reaction, precipitating in water, washing the precipitated polymer with ethanol 6 times, and finally drying in a vacuum drying oven at 95°C to constant weight; the mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsiloxane, azobisisobutyronitrile, and the high-boiling-point solvent is 1:1.2:0.3:0.2:0.04:15; and the high-boiling-point solvent is N,N-dimethylformamide.

[0047] The vinyl-containing hyperbranched polysiloxane is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN102276836B.

[0048] A preparation method of the insulating varnish for the new energy vehicle battery pack comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain the insulating varnish for the new energy vehicle battery pack.

[0049] Comparative Example 1

[0050] An insulating varnish for a new energy vehicle battery pack and a preparation method thereof are basically the same as those in Example 1, except that methylvinylsilane and 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone are not added during the preparation of the functional film-forming copolymer.

[0051] Comparative Example 2

[0052] An insulating varnish for a new energy vehicle battery pack and a preparation method thereof are basically the same as those in Example 1, except that 2,4,6-trivinyl boroxine and bicyclo[2.2.1]heptanedimethylamine are not added.

[0053] In order to further illustrate the beneficial technical effects of the insulating paint for new energy vehicle battery packs of each embodiment of the present invention, relevant performance tests were performed on the insulating paint for new energy vehicle battery packs prepared in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1. The test method is as follows: the curing temperature of the insulating paint coating for new energy vehicle battery packs of Examples 1 to 5 and Comparative Examples 1 to 2 is 90°C, the curing time is 1 hour, and the auxiliary wavelength is 220nm ultraviolet light irradiation for 5 minutes. The adhesion grade is tested with reference to the GB / T1720-2020 circle method; the high and low temperature cycle resistance test conditions are: 80±2°C, 95%RH 4h, 80°C to -40°C 2h (temperature change rate 1°C / min), -40±2°C 4h, -40°C to 80°C, 95%RH 2h (temperature change rate 1℃ / min), the above 12h is one cycle. After the 60-cycle test is completed, the sample should be placed at room temperature for more than 16h. If the paint film has no blistering, wrinkling or falling off, it passes, otherwise it fails; the volume resistivity of the paint film after each case is measured with reference to GB / T 1410-2006; the impact resistance of the paint film is measured with reference to GB / T 1732-2020.

[0054]

[0055] As can be seen from Table 1, the insulating varnish for new energy vehicle battery packs disclosed in each embodiment of the present invention has higher adhesion and resistance to high and low temperature cycling than the comparative example products, and has better insulation and toughness; the addition of methylvinylsilane, 3-(1,1-difluoro-2-propene-1-yl)-2(1H)-quinoxalinone, 2,4,6-trivinylcycloboroxane and bicyclo[2.2.1]heptanedimethylamine is beneficial to improving the above properties.

[0056] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An insulating varnish for a new energy vehicle battery pack, characterized in that: The invention is prepared from the following raw materials in parts by weight: 30-40 parts of vinyl-containing hyperbranched polysiloxane, 15-20 parts of functional film-forming copolymer, 20-30 parts of filler, 1-3 parts of 5-vinylbicyclo[2.2.1]hept-2-ene, 2-4 parts of 2,4-diamino-6-diallylamino-1,3,5-triazine, 1-3 parts of 2,4,6-trivinylcycloboroxine, 1-3 parts of bicyclo[2.2.1]heptanedimethylamine, 0.4-0.8 parts of photoinitiator, 1-3 parts of auxiliary agent and 30-40 parts of solvent; the functional film-forming copolymer is prepared from allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone and methylvinylsiloxane through free radical copolymerization.

2. The insulating paint for new energy vehicle battery pack according to claim 1, characterized in that: The solvent is at least one of ethylene glycol ethyl ether acetate, acetone, and propylene glycol methyl ether.

3. The insulating paint for new energy vehicle battery pack according to claim 1, characterized in that: The auxiliary agent is a mixture formed by mixing a defoamer, a leveling agent and a dispersant in a mass ratio of 1:(0.8-1.2):(1-1.5).

4. The insulating paint for new energy vehicle battery pack according to claim 3, characterized in that: The defoaming agent is one or more of tributyl phosphate, defoaming agent Deqian 3100, and defoaming agent BYK088; the leveling agent is at least one of German BYK leveling agent BYK-333 and silicone leveling agent HY-5030; the dispersant is at least one of polycarboxylate dispersant 5040 and sodium hexametaphosphate.

5. The insulating paint for new energy vehicle battery pack according to claim 1, characterized in that: The photoinitiator is at least one of benzoin ethyl ether, 2,4-dihydroxybenzophenone and benzoin.

6. The insulating paint for new energy vehicle battery pack according to claim 1, characterized in that: The filler is at least one of silicon micropowder, mica powder, double fly ash, and titanium dioxide; and the particle size of the filler is 800-1200 meshes.

7. The insulating paint for new energy vehicle battery pack according to claim 1, characterized in that: The preparation method of the functional film-forming copolymer comprises the following steps: adding allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsilane and azobisisobutyronitrile to a high-boiling-point solvent, stirring and reacting at 60-70° C. in a nitrogen atmosphere for 4-6 hours, cooling to room temperature after the reaction, precipitating in water, washing the precipitated polymer with ethanol for 3-6 times, and finally drying in a vacuum drying oven at 85-95° C. to constant weight.

8. The insulating varnish for new energy vehicle battery pack according to claim 7, characterized in that: The mass ratio of the allyl succinimidyl carbonate, glycidyl methacrylate, 3-(1,1-difluoro-2-propylene-1-yl)-2(1H)-quinoxalinone, methylvinylsilane, azobisisobutyronitrile, and high-boiling-point solvent is 1:(0.8-1.2):(0.1-0.3):0.2:(0.02-0.04):(8-15); the high-boiling-point solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

9. A method for preparing the insulating varnish for new energy vehicle battery pack according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: uniformly mixing the raw materials according to parts by weight to obtain insulating paint for new energy vehicle battery packs.

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