Powder coating for battery liquid cooling plate and preparation method thereof

Abstract

The present invention discloses a powder coating for a battery liquid cooling plate and a preparation method thereof. The powder coating for a battery liquid cooling plate of the present invention comprises the following components in parts by mass: 200 to 350 parts of epoxy resin filled and modified with a thermal conductive material; 30 to 80 parts of a curing agent; 100 to 300 parts of a filler; 3 to 8 parts of an accelerator; 1 to 3 parts of a leveling agent; 1 to 2.5 parts of a degassing agent; 6 to 12 parts of a pigment; and 15 to 20 parts of a flame retardant. The powder coating for a battery liquid cooling plate of the present invention can be rapidly cured at low temperatures, and the coating prepared therefrom has the advantages of high thermal conductivity, excellent acid and alkali resistance, excellent impact resistance, high dielectric strength, excellent insulation performance, excellent flame retardancy, good resistance to double 85 moisture and heat, and good high temperature resistance. It can fully meet the coating requirements of battery liquid cooling plates and is suitable for large-scale industrial applications.

Description

Technical Field

[0001] The present invention relates to the technical field of powder coatings, and in particular to a powder coating for a battery liquid cooling plate and a preparation method thereof. Background Art

[0002] With the increasing scarcity of traditional energy and environmental concerns, new energy vehicles (NEVs) have become a hot topic, poised to completely replace traditional fuel vehicles in the future. Compared to traditional fuel vehicles, NEVs incorporate three additional systems (electric motor, power battery, and electronic control), making thermal management systems more complex and costly. The power battery is the most heat-sensitive component in NEVs, with the most significant cost increases. As the heart of NEVs, the operating state of the power battery directly impacts vehicle performance, necessitating industry-wide attention to its safety, service life, and performance. Battery cooling is undoubtedly a crucial component of the entire battery thermal management process. The liquid cooling plate in the battery cooling system of NEVs is in direct contact with the power battery. To ensure safe and continuous operation of the battery cooling system, a protective coating is typically required on the outer surface of the liquid cooling plate. However, due to the long-term exposure to high temperature, high humidity, and high voltage, the liquid cooling plate is susceptible to corrosion caused by penetration of the battery electrolyte, making conventional coatings inadequate. Summary of the Invention

[0003] The present invention is directed to a powder coating for a battery liquid cooling plate and a preparation method thereof.

[0004] The technical solution adopted by the present invention is:

[0005] A powder coating for a battery liquid cooling plate, comprising the following components in parts by mass:

[0006] Thermally conductive material-filled modified epoxy resin: 200 to 350 parts;

[0007] Curing agent: 30 to 80 parts;

[0008] Filler: 100 to 300 parts;

[0009] Accelerator: 3 to 8 parts;

[0010] Leveling agent: 1 to 3 parts;

[0011] Degassing agent: 1 to 2.5 parts;

[0012] Pigment: 6 to 12 parts;

[0013] Flame retardant: 15 to 20 parts.

[0014] Preferably, a powder coating for a battery liquid cooling plate comprises the following components in parts by mass:

[0015] Thermally conductive material-filled modified epoxy resin: 270 to 320 parts;

[0016] Curing agent: 35 to 55 parts;

[0017] Filler: 100 to 150 parts;

[0018] Accelerator: 5 to 7 parts;

[0019] Leveling agent: 2 to 3 parts;

[0020] Degassing agent: 1.5 to 2 parts;

[0021] Pigment: 7 to 10 parts;

[0022] Flame retardant: 15 to 20 parts.

[0023] Preferably, the mass ratio of the epoxy resin filled with the thermally conductive material and the curing agent is 1:0.08-0.25.

[0024] Further preferably, the mass ratio of the epoxy resin filled with the thermally conductive material and the curing agent is 1:0.10-0.20.

[0025] Preferably, the epoxy resin modified with thermally conductive material is prepared by mixing epoxy resin, thermally conductive material, and silane coupling agent, stirring the mixture at a constant temperature of 110°C to 130°C, and then cooling and crushing the mixture into tablets to obtain the epoxy resin modified with thermally conductive material. Modifying the epoxy resin with thermally conductive material can ensure that the thermal conductivity of the coating film made from powder coating for battery liquid cooling plates exceeds 1.5 W / mK.

[0026] Further preferably, the epoxy resin modified by filling thermal conductive material is made by the following method: epoxy resin, thermal conductive material and silane coupling agent are mixed, and then stirred at a constant temperature of 115°C to 120°C, and then tableted and crushed after cooling to obtain the epoxy resin modified by filling thermal conductive material.

[0027] Preferably, the mass ratio of the epoxy resin, the thermal conductive material, and the silane coupling agent is 1:0.04-0.50:0.02-0.20.

[0028] Further preferably, the mass ratio of the epoxy resin, the thermal conductive material, and the silane coupling agent is 1:0.13-0.34:0.04-0.09.

[0029] Preferably, the epoxy resin is a multifunctional phenolic epoxy resin with an epoxy equivalent weight of 170 g / eq to 250 g / eq and a softening point of 70°C to 100°C. The multifunctional phenolic epoxy resin, when combined with a dicyandiamide curing agent and / or a phenolic curing agent, can cure the powder coating for battery liquid cooling plates into a film at 160°C / 10 min. The resulting coating exhibits no significant change in appearance or performance after immersion in a 5% HCl solution or a 5% NaOH solution for 240 hours, no cracking under an 80 kg·cm impact, a dielectric strength greater than 65 kV / mm, an insulation resistance greater than 900 MΩ, a flame retardancy rating reaching UL94-V0, and no significant change in appearance or performance after 1000 hours of wet heat and humidity resistance or exposure to 150°C for 1000 hours.

[0030] More preferably, the epoxy resin is tetraphenol ethane epoxy resin, with an epoxy equivalent of 180 g / eq to 230 g / eq and a softening point of 75° C. to 90° C.

[0031] Preferably, the thermally conductive material is at least one of aluminum nitride micropowder and boron nitride micropowder.

[0032] Further preferably, the thermally conductive material is boron nitride powder.

[0033] More preferably, the thermally conductive material is cubic boron nitride powder.

[0034] Preferably, the silane coupling agent is at least one of 3-aminopropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, and γ-aminopropylmethyldimethoxysilane.

[0035] Preferably, the constant temperature stirring is carried out at a stirring speed of 300 r / min to 500 r / min, and the stirring time is 10 min to 30 min.

[0036] More preferably, the constant temperature stirring is carried out at a stirring speed of 350 r / min to 400 r / min, and the stirring time is 15 min to 20 min.

[0037] Preferably, the target temperature of the cooling is 30°C to 50°C.

[0038] More preferably, the target temperature of the cooling is 35°C to 45°C.

[0039] Preferably, the curing agent is at least one of a dicyandiamide curing agent and a phenol curing agent.

[0040] More preferably, the curing agent is compounded by a dicyandiamide curing agent and a phenolic curing agent in a mass ratio of 1:0.5 to 1.0.

[0041] Preferably, the dicyandiamide curing agent is at least one of Shell Chemical's Epikure 108FF, Ciba's HT 2831, and Dow Chemical's DEH40.

[0042] Preferably, the phenolic curing agent is at least one of Dow Chemical's curing agent DEH 84, Dow Chemical's curing agent DEH 87, and Kuodu Chemical (Kunshan) Co., Ltd.'s curing agent KD 406.

[0043] Preferably, the filler is at least one of barium sulfate powder, silicon powder, mica powder and titanium dioxide.

[0044] More preferably, the filler is at least one of silicon micropowder and mica powder.

[0045] Preferably, the accelerator is an imidazole accelerator.

[0046] More preferably, the accelerator is at least one of 2-phenylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2-methylimidazole, imidazole epoxy adduct, and imidazole isocyanate adduct.

[0047] More preferably, the accelerator is at least one of 2-phenylimidazole, 2-ethylimidazole, and 2-methylimidazole.

[0048] Preferably, the leveling agent is an acrylic leveling agent.

[0049] More preferably, the leveling agent is at least one of polyethyl acrylate, polybutyl acrylate, poly-2-ethylhexyl acrylate, and butyl acrylate-ethyl acrylate copolymer.

[0050] More preferably, the leveling agent is at least one of polyethyl acrylate and polybutyl acrylate.

[0051] Preferably, the degassing agent is benzoin.

[0052] Preferably, the pigment is at least one of iron oxide red, iron oxide yellow, carbon black, ultramarine, iron yellow, phthalocyanine blue, and phthalocyanine green.

[0053] Preferably, the flame retardant is an organophosphorus flame retardant.

[0054] More preferably, the flame retardant is hexaphenoxycyclotriphosphazene.

[0055] Preferably, the battery liquid cooling plate is coated with powder coating. 50The particle size (median particle size) is 25 μm to 45 μm.

[0056] Further preferably, the battery liquid cooling plate is coated with powder coating D 50 The particle size is 30μm~40μm.

[0057] A method for preparing the powder coating for battery liquid cooling plates as described above comprises the following steps: mixing all components, then extruding, tableting, cooling, crushing and screening to obtain the powder coating for battery liquid cooling plates.

[0058] Preferably, the extrusion equipment is a twin-screw extruder.

[0059] Preferably, the heating temperature of the first zone of the twin-screw extruder is 85°C to 100°C, and the heating temperature of the second zone is 95°C to 110°C.

[0060] Further preferably, the heating temperature of the first zone of the twin-screw extruder is 90°C to 95°C, and the heating temperature of the second zone is 100°C to 105°C.

[0061] A battery liquid cooling plate, the surface of which is covered with a coating made of the above-mentioned powder coating for the battery liquid cooling plate.

[0062] The beneficial effects of the present invention are as follows: the powder coating for the battery liquid cooling plate of the present invention can be rapidly cured at low temperature, and the coating made thereof has the advantages of high thermal conductivity, excellent acid and alkali resistance, excellent impact resistance, high dielectric strength, excellent insulation performance, excellent flame retardancy, good resistance to double 85 moisture and heat, and good high temperature resistance. It can fully meet the coating requirements of the battery liquid cooling plate and is suitable for large-scale industrial applications. DETAILED DESCRIPTION

[0063] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0064] It should be noted that the following embodiments do not limit the scope of protection claimed in the present invention.

[0065] Unless otherwise specified, the raw materials, reagents and devices used in Examples 1 to 3 and Comparative Examples 1 to 4 can be purchased through conventional commercial channels or prepared by existing known methods.

[0066] The powder coating refers to a powder coating composition, and the coating film refers to a film layer made of the powder coating composition.

[0067] The raw materials and equipment used in Examples 1 to 3 and Comparative Examples 1 to 4 are as follows:

[0068] Twin-screw extruder: JFY-30 crawler-type twin-screw extruder.

[0069] Tetraphenol ethane epoxy resin: brand EPON 1031, American HEXION EPON, epoxy equivalent weight is 198g / eq, softening point is 83℃.

[0070] Bisphenol A epoxy resin: brand GESR903, Zhuhai Hongchang Electronic Materials Co., Ltd., epoxy equivalent weight is 730g / eq, softening point is 90℃.

[0071] Cubic boron nitride powder: brand CBN-M800, Funaike Superhard Materials Co., Ltd.

[0072] Curing agent Epikure 108FF: Shell Chemical.

[0073] Curing agent DEH 84: Dow Chemical.

[0074] Silica powder: Fengyang Rongju Mineral Products Co., Ltd.

[0075] 2-Methylimidazole: Hubei Changyao Biotechnology Co., Ltd.

[0076] Leveling agent BYK 360P: BYK Chemical.

[0077] Benzoin: MIWON BENZOIN.

[0078] Hexaphenoxycyclotriphosphazene: Tianjin CITIC Kaitai Chemical Co., Ltd.

[0079] Example 1:

[0080] A powder coating for battery liquid cooling plate, the composition of which is shown in the following table:

[0081] Table 1 Composition of powder coating for battery liquid cooling plate

[0082] Components parts by mass Thermally conductive material filled modified epoxy resin 250 Curing agent Epikure 108FF 25 Curing agent DEH 84 15 Silica powder 150 2-Methylimidazole 5 Leveling agent BYK 360P 2.5 Benzoin 1.5 carbon black 8 Hexaphenoxycyclotriphosphazene 15

[0083] Note:

[0084] The epoxy resin modified by thermal conductive material filling is prepared by the following method: 135 parts by mass of tetraphenol ethane epoxy resin EPON 1031 and 25 parts by mass of cubic boron nitride micropowder CBN-M800 are mixed, and then 7 parts by mass of 3-aminopropyltrimethoxysilane are added. The mixture is then stirred at a constant temperature of 115° C. and a stirrer speed of 400 r / min for 20 minutes. The mixture is then cooled to 35° C. and crushed into tablets to obtain the epoxy resin modified by thermal conductive material filling.

[0085] The preparation method of the powder coating for the battery liquid cooling plate is as follows:

[0086] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95 ° C, and the heating temperature of the second zone was 105 ° C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating for battery liquid cooling plate (D 50 Particle size is 37 μm).

[0087] Example 2:

[0088] A powder coating for battery liquid cooling plate, the composition of which is shown in the following table:

[0089] Table 2 Composition of powder coating for battery liquid cooling plate

[0090]

[0091] The preparation method of the powder coating for the battery liquid cooling plate is as follows:

[0092] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95 ° C, and the heating temperature of the second zone was 105 ° C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating for battery liquid cooling plate (D 50 Particle size is 38 μm).

[0093] Example 3:

[0094] A powder coating for battery liquid cooling plate, the composition of which is shown in the following table:

[0095] Table 3 Composition of a powder coating for battery liquid cooling plate

[0096]

[0097]

[0098] The preparation method of the powder coating for the battery liquid cooling plate is as follows:

[0099] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95 ° C, and the heating temperature of the second zone was 105 ° C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating for battery liquid cooling plate (D 50 Particle size is 36 μm).

[0100] Comparative Example 1:

[0101] A powder coating, the composition of which is shown in the following table:

[0102] Table 4 Composition of a powder coating

[0103] Components parts by mass Tetraphenol ethylene epoxy resin EPON 1031 250 Curing agent Epikure 108FF 25 Curing agent DEH 84 15 Silica powder 150 2-Methylimidazole 5 Leveling agent BYK 360P 2.5 Benzoin 1.5 carbon black 8 Hexaphenoxycyclotriphosphazene 20

[0104] The preparation method of the above powder coating is as follows:

[0105] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95°C and the heating temperature of the second zone was 105°C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating (D 50 Particle size is 37 μm). Comparative Example 2:

[0106] A powder coating, the composition of which is shown in the following table:

[0107] Table 5 Composition of a powder coating

[0108] Components parts by mass Bisphenol A epoxy resin GESR903 250 Curing agent Epikure 108FF 25 Silica powder 150 2-Methylimidazole 5 Leveling agent BYK 360P 2.5 Benzoin 1.5 carbon black 8 Hexaphenoxycyclotriphosphazene 20

[0109] The preparation method of the above powder coating is as follows:

[0110] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95°C and the heating temperature of the second zone was 105°C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating (D 50 Particle size is 37 μm). Comparative Example 3:

[0111] A powder coating, the composition of which is shown in the following table:

[0112] Table 6 Composition of a powder coating

[0113]

[0114] Note:

[0115] The thermally conductive material-filled modified bisphenol A epoxy resin is prepared by the following method: 135 parts by mass of bisphenol A epoxy resin GESR903 and 25 parts by mass of cubic boron nitride powder CBN-M800 are mixed, and then 7 parts by mass of 3-aminopropyltrimethoxysilane are added. The mixture is then stirred at a constant temperature of 115° C. and a stirrer speed of 400 r / min for 20 minutes. The mixture is then cooled to 35° C. and crushed into tablets to obtain the thermally conductive material-filled modified bisphenol A epoxy resin.

[0116] The preparation method of the above powder coating is as follows:

[0117] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95°C and the heating temperature of the second zone was 105°C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating (D 50 Particle size is 37 μm). Comparative Example 4:

[0118] A powder coating, the composition of which is shown in the following table:

[0119] Table 7 Composition of a powder coating

[0120] Components parts by mass Tetraphenol ethylene epoxy resin EPON 1031 205 Cubic Boron Nitride Powder CBN-M800 45 Curing agent Epikure 108FF 25 Curing agent DEH 84 15 Silica powder 150 2-Methylimidazole 5 Leveling agent BYK 360P 2.5 Benzoin 1.5 carbon black 8 Hexaphenoxycyclotriphosphazene 20

[0121] The preparation method of the above powder coating is as follows:

[0122] All components were added into the mixing tank according to the proportion, fully mixed and crushed for 8 minutes, and then the obtained mixture was sent to the twin-screw extruder for extrusion. The heating temperature of the first zone of the twin-screw extruder was 95°C and the heating temperature of the second zone was 105°C. The extruded material was then sent to the tablet press for tableting, and then cooled, crushed, sieved and packaged to obtain the powder coating (D 50 Particle size is 37μm). Performance test:

[0123] The surface of the battery liquid cooling plate was pretreated with a zinc phosphate solution, and then the powder coatings for battery liquid cooling plates of Examples 1 to 3 and the powder coatings of Comparative Examples 1 to 4 were applied to the pretreated surface of the battery liquid cooling plate using a high-voltage electrostatic spray gun. The coating thickness was 100 μm. The coating was then cured in a curing oven at 160° C. for 10 minutes to form a coating film. The performance test results of the coating films are shown in Tables 8 and 9:

[0124] Table 8 Performance test results of the coating films made of powder coatings for battery liquid cooling plates of Examples 1 to 3

[0125]

[0126] Table 9 Performance test results of coating films made from powder coatings of Comparative Examples 1 to 4

[0127]

[0128]

[0129] From Table 8 and Table 9, we can see that:

[0130] 1) The powder coatings for battery liquid cooling plates of Examples 1 to 3 can be rapidly cured at low temperatures. The resulting coating films have excellent acid and alkali resistance, impact resistance, dielectric strength, insulation, flame retardancy, resistance to double 85 humidity and heat, and high temperature resistance, meeting various coating requirements for battery liquid cooling plates.

[0131] 2) The powder coating of Comparative Example 1 (incorporating tetraphenol ethylene epoxy resin EPON 1031 without modification with cubic boron nitride powder) had a coating film that met most of the coating requirements for battery liquid cooling plates, but had a significantly low thermal conductivity.

[0132] 3) The powder coating of Comparative Example 2 (added with bisphenol A epoxy resin) was difficult to achieve low-temperature rapid curing (160°C / 10 min), resulting in poor performance of the coating film under the curing condition of 160°C / 10 min;

[0133] 4) The powder coating of Comparative Example 3 (containing a bisphenol A epoxy resin modified with a thermally conductive material and no flame retardant) partially met the coating requirements for battery liquid cooling plates, but its chemical resistance, flame retardancy, and high-temperature resistance were significantly low.

[0134] 5) The thermal conductivity of the powder coating of Comparative Example 4 (in which tetraphenol ethylene epoxy resin EPON 1031 and cubic boron nitride powder were directly added without pre-modifying the tetraphenol ethylene epoxy resin EPON 1031 with cubic boron nitride powder) was improved compared to the coatings made from the powder coatings of Comparative Examples 1 and 2, but the improvement was small.

[0135] In summary, the present invention significantly improves the thermal conductivity of the coating film made of powder coating by filling and modifying the multifunctional phenolic epoxy resin with a thermally conductive material, and significantly improves the flame retardant efficiency while ensuring environmental protection and pollution-free by adding hexaphenoxycyclotriphosphazene (phosphorus-nitrogen synergistic flame retardant). At the same time, the combination of dicyandiamide curing agent and phenol curing agent enables the powder coating to achieve low-temperature rapid curing. The final coating film has excellent acid and alkali resistance, impact resistance, dielectric strength, insulation performance, resistance to double 85 humidity and heat, high temperature resistance, etc., which can better meet the coating requirements of battery liquid cooling plates.

[0136] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A powder coating for a battery liquid cooling plate, characterized in that: The composition comprises the following components in parts by weight: Thermally conductive material-filled modified epoxy resin: 200 to 350 parts; Curing agent: 30 to 80 parts; Filler: 100 to 300 parts; Accelerator: 3 to 8 parts; Leveling agent: 1 to 3 parts; Degassing agent: 1 to 2.5 parts; Pigment: 6 to 12 parts; Flame retardant: 15 to 20 parts; The epoxy resin modified by thermal conductive material filling is prepared by the following method: epoxy resin, thermal conductive material and silane coupling agent are mixed, and then the mixture is stirred at a constant temperature of 110° C. to 130° C., and then the mixture is pressed and crushed after cooling to obtain the epoxy resin modified by thermal conductive material filling; The mass ratio of the epoxy resin, the thermal conductive material, and the silane coupling agent is 1:0.04-0.50:0.02-0.20; The epoxy resin is a multifunctional phenolic epoxy resin with an epoxy equivalent weight of 170 g / eq to 250 g / eq and a softening point of 70° C. to 100° C. The thermal conductive material is at least one of aluminum nitride micropowder and boron nitride micropowder.

2. The powder coating for battery liquid cooling plate according to claim 1, characterized in that: The constant temperature stirring is carried out under the condition that the stirring speed of the stirrer is 300r / min to 500r / min, and the stirring time is 10min to 30min; the target temperature of the cooling is 30℃ to 50℃.

3. The powder coating for battery liquid cooling plate according to claim 1 or 2, characterized in that: The curing agent is at least one of a dicyandiamide curing agent and a phenol curing agent; the filler is at least one of barium sulfate powder, silicon micropowder, mica powder, and titanium dioxide; the accelerator is an imidazole accelerator; the leveling agent is an acrylate leveling agent; the degassing agent is benzoin; and the flame retardant is an organophosphorus flame retardant.

4. The powder coating for battery liquid cooling plate according to claim 1 or 2, characterized in that: The battery liquid cooling plate is coated with powder coating 50 The particle size is 25μm~45μm.

5. A method for preparing a powder coating for a battery liquid cooling plate according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: mixing all components, and then performing extrusion, tableting, cooling, crushing and screening to obtain powder coating for battery liquid cooling plate.

6. A battery liquid cooling plate, characterized in that: The surface is covered with a coating made of the powder coating for battery liquid cooling plate according to any one of claims 1 to 4.

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