Polyacrylate coating, preparation method thereof, battery and electric device

Abstract

The invention relates to a polyacrylate coating, a preparation method thereof, a battery and an electric device. The polyacrylate coating is prepared from the following raw material components in parts by weight: 40 to 70 parts of acrylate copolymer emulsion, 10 to 25 parts of flame-retardant filler, 0.5 to 5 parts of adhesion promoter and 10 to 45 parts of water, the acrylate copolymer emulsion is prepared by emulsion copolymerization of an acrylate monomer, an alkyl ester monomer, a nitrogen-containing monomer and a phosphorus-containing monomer in the presence of an initiator, and an emulsifier adopted in emulsion copolymerization comprises a phosphorus-containing anionic emulsifier and a nitrogen-containing nonionic emulsifier; the chain length of alkyl in the alkyl ester monomer is C10-C18. The polyacrylate coating has good damping and flame retardant properties.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to a polyacrylate coating and its preparation method, a battery, and an electrical device. Background Technology

[0002] New energy vehicle power battery packs face the dual challenges of mechanical vibration and thermal runaway risks during operation. On the one hand, wide-frequency vibrations (10Hz~200Hz) caused by road excitation can accelerate the loosening of battery module connectors, leading to increased contact resistance or even open circuits. On the other hand, the high temperatures released during battery thermal runaway (e.g., >800℃) may ignite the casing material.

[0003] To address these issues, traditional methods involve applying damping sheets or coatings to the inner wall of the battery casing and adding flame retardants. However, while commercially available butyl rubber / asphalt-based damping materials are effective from -20°C to 80°C, battery packs exceed their effective temperature range in cold environments (e.g., -40°C) or during fast charging (e.g., >100°C), leading to a significant decrease in the loss factor (tanδ) (e.g., from a peak of 0.8 to below 0.1). Furthermore, while adding flame retardants improves flame retardancy, it degrades damping and mechanical properties.

[0004] Therefore, it is necessary to provide a battery casing coating that can effectively balance good damping and flame retardant properties. Summary of the Invention

[0005] Based on this, this application provides a polyacrylate coating and its preparation method, a battery, and an electrical device. This polyacrylate coating can achieve both good damping and flame-retardant properties.

[0006] A first aspect of this application provides a polyacrylate coating, comprising, by weight, the following raw material components:

[0007] 40-70 parts of acrylate copolymer emulsion

[0008] 10 to 25 parts of flame retardant filler

[0009] Adhesion promoter 0.5 to 5 parts, and

[0010] 10 to 45 parts water;

[0011] The acrylate copolymer emulsion is prepared by emulsion copolymerization of acrylate monomers, alkyl ester monomers, nitrogen-containing monomers and phosphorus-containing monomers in the presence of an initiator. The emulsifiers used in the emulsion copolymerization include phosphorus-containing anionic emulsifiers and nitrogen-containing nonionic emulsifiers.

[0012] The alkyl chain length in the alkyl ester monomer is C10~C18.

[0013] In one embodiment, the phosphorus-containing anionic emulsifier includes one or more of alkyl phosphates, polyoxyethylene phosphates, and fatty alcohol polyoxyethylene phosphates.

[0014] In one embodiment, the nitrogen-containing nonionic emulsifier includes one or more of alkyl isopropanol amide and amino oleate.

[0015] In one embodiment, the nitrogen-containing monomer includes one or more of acrylamide monomers and acrylonitrile monomers;

[0016] Optionally, the nitrogen-containing monomer includes one or more of acrylamide, methacrylamide, N-hydroxymethylacrylamide, acrylonitrile, and diacetone acrylamide.

[0017] In one embodiment, the phosphorus-containing monomer includes one or more organophosphate monomers;

[0018] Optionally, the phosphorus-containing monomer includes one or more of styrene phosphate, diethyl vinyl phosphate, and 2-acrylamidoethyl phosphate.

[0019] In one embodiment, the acrylate monomer includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and isooctyl methacrylate; and / or,

[0020] The alkyl chain in the alkyl ester monomer has a C12-C18 length and optionally includes unsaturated double bonds. Further optionally, the alkyl ester monomer includes one or more of lauryl acrylate, lauryl methacrylate, and octadecyl acrylate; and / or,

[0021] The flame-retardant filler includes one or more of aluminum hydroxide, zinc borate, and aluminum hypophosphite. Optionally, the particle size D50 of the flame-retardant filler is 1 μm to 10 μm, and the surface is treated with a silane coupling agent; and / or,

[0022] The adhesion promoter includes one or more of silanes, phosphates, and titanates; and / or,

[0023] The initiator includes one or more of ammonium persulfate, sodium persulfate, and potassium persulfate;

[0024] Optionally, the amount of the initiator is 0.3% to 1% of the total weight of the acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer.

[0025] In one embodiment, the acrylate copolymer emulsion comprises, by weight, the following raw material components:

[0026] The acrylate monomer is 30 to 90 parts.

[0027] The alkyl ester monomer is 5 to 35 parts.

[0028] The nitrogen-containing monomer is 2 to 20 parts.

[0029] The phosphorus-containing monomer is 0.1 to 20 parts.

[0030] The phosphorus-containing anionic emulsifier is 0.1 to 20 parts, and,

[0031] The nitrogen-containing nonionic emulsifier is 0.1 to 20 parts.

[0032] A second aspect of this application provides a method for preparing the aforementioned polyacrylate coating, comprising the following steps:

[0033] The phosphorus-containing anionic emulsifier was mixed with water to prepare an aqueous phase;

[0034] The acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer are mixed to prepare an oil phase;

[0035] The oil phase is added to the aqueous phase for pre-emulsification to prepare a pre-emulsion.

[0036] The nitrogen-containing nonionic emulsifier is mixed with water to prepare a mixture;

[0037] A portion of the pre-emulsion, the mixture, and a portion of the initiator are mixed and emulsified to prepare a seed emulsion.

[0038] The seed emulsion is mixed with the remaining pre-emulsion and the remaining initiator, and then matured to prepare the acrylate copolymer emulsion.

[0039] The acrylic copolymer emulsion is mixed with the flame retardant filler, the adhesion promoter and the water to prepare the polyacrylate coating.

[0040] A third aspect of this application provides a battery, including a battery pack and a housing, the battery pack being housed within the housing, and the inner surface of the housing being provided with a coating, the coating being formed by curing the polyacrylate coating described in the first aspect;

[0041] Optionally, the thickness of the coating is 0.2 mm to 1 mm;

[0042] Optionally, the curing conditions include: a temperature of 80℃~120℃ and a time of 10min~30min;

[0043] Optionally, the housing may be made of aluminum alloy, galvanized steel, or engineering plastic.

[0044] A fourth aspect of this application provides an electrical device, including the battery described in the third aspect;

[0045] Optionally, the electrical device includes a vehicle.

[0046] The aforementioned polyacrylate coating is formulated with acrylate copolymer emulsion, flame-retardant filler, and adhesion promoter. The acrylate copolymer emulsion, based primarily on acrylate monomers, incorporates C10-C18 long-chain alkyl ester monomers, which utilize internal plasticizing effects to broaden the damping temperature range. Simultaneously, nitrogen-containing and phosphorus-containing monomers are added, which, during combustion, generate a phosphorus-nitrogen synergistic flame-retardant effect, forming a dense, expanded char layer for excellent flame retardancy. Furthermore, in addition to the aforementioned multifunctional monomers, phosphorus-containing anionic emulsifiers and nitrogen-containing nonionic emulsifiers are used for surface activation, improving the compatibility between these multifunctional monomers and thus fully leveraging the wide-temperature-range damping and flame-retardant effects. The resulting polyacrylate coating achieves both good damping and flame-retardant properties and can be directly coated onto battery casings to provide vibration suppression and fire safety functions.

[0047] In addition, the above-mentioned polyacrylate coatings, through the compatibility of their components, not only have good damping and flame retardant properties, but also good mechanical properties and substrate adhesion properties. Detailed Implementation

[0048] The following detailed description, in conjunction with specific embodiments, illustrates the polyacrylate coating, its preparation method, battery, and electrical device of this application. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0050] As used herein, the terms “and / or,” “or / and,” and “and / or” may include any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all the related listed items.

[0051] In this article, "one or more" refers to any one, two or more of the listed items.

[0052] In this application, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0053] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0054] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0055] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0056] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0057] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0058] In this application, room temperature generally refers to 4℃~30℃, and preferably 20±5℃.

[0059] Some embodiments of this application provide polyacrylate coatings, comprising, by weight, the following raw material components:

[0060] 40-70 parts of acrylate copolymer emulsion

[0061] 10 to 25 parts of flame retardant filler

[0062] Adhesion promoter 0.5 to 5 parts, and

[0063] 10 to 45 parts water;

[0064] The acrylate copolymer emulsion is prepared by emulsion copolymerization of acrylate monomers, alkyl ester monomers, nitrogen-containing monomers and phosphorus-containing monomers in the presence of an initiator. The emulsifiers used in the emulsion copolymerization include phosphorus-containing anionic emulsifiers and nitrogen-containing nonionic emulsifiers.

[0065] The alkyl chain length in the alkyl ester monomer is C10~C18.

[0066] Specifically, the acrylate copolymer emulsion may be present in parts by weight including but not limited to: 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or any combination thereof.

[0067] Specifically, the flame-retardant filler may be expressed in parts by weight including but not limited to: 10 parts, 13 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, or any combination thereof.

[0068] Specifically, the adhesion promoter is present in parts by weight including but not limited to: 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, or any combination thereof.

[0069] Specifically, the weight parts of the water include, but are not limited to: 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, or any two of the foregoing.

[0070] In some embodiments, the phosphorus-containing anionic emulsifier includes one or more of alkyl phosphates, polyoxyethylene phosphates, and fatty alcohol polyoxyethylene phosphates.

[0071] In some embodiments, the nitrogen-containing nonionic emulsifier includes one or more of alkyl isopropanolamide and amino oleate.

[0072] In some embodiments, the nitrogen-containing monomer includes one or more of acrylamide monomers and acrylonitrile monomers. Further, the nitrogen-containing monomer includes one or more of acrylamide, methacrylamide, N-hydroxymethylacrylamide, acrylonitrile, and diacetone acrylamide.

[0073] In some embodiments, the phosphorus-containing monomer comprises one or more organophosphate monomers. Further, the phosphorus-containing monomer comprises one or more of styrene phosphate, diethyl vinyl phosphate, and 2-acrylamidoethyl phosphate.

[0074] Without limitation, both the phosphorus-containing anionic emulsifier and the phosphorus-containing monomer contain carbon-phosphorus bonds (CP) in their molecular structure, and the phosphorus content is ≥6% by mass. Specifically, the phosphorus content by mass includes, but is not limited to: 6%, 8.5%, 10%, 12%, 14.8%, 18%, 20%, 25%, or any range between the foregoing.

[0075] Without limitation, both the nitrogen-containing nonionic emulsifier and the nitrogen-containing monomer contain carbon-nitrogen bonds (CN) in their molecular structure, and the nitrogen content is ≥0.75% by mass. Specifically, the nitrogen content includes, but is not limited to: 0.75%, 1%, 3%, 5.1%, 8.3%, 10%, 13%, 15%, 19.7%, 20%, 25%, or any range between the foregoing.

[0076] Without limitation, the ratio of the sum of the molar amounts of phosphorus in the phosphorus-containing anionic emulsifier and the phosphorus-containing monomer to the sum of the molar amounts of nitrogen in the nitrogen-containing nonionic emulsifier and the nitrogen-containing monomer is 1:(0.2~1), so that the phosphorus-nitrogen molar ratio released during combustion can reach 1:(0.5~2).

[0077] In some embodiments, the acrylate monomer includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and isooctyl methacrylate. Without limitation, to reduce coating costs, in addition to the acrylate monomer, other monomers, such as styrene monomer, may be added to the main monomer of the coating.

[0078] In some embodiments, the alkyl chain in the alkyl ester monomer has a length of C12 to C18, optionally including unsaturated double bonds, and further optionally including one or more of lauryl acrylate, lauryl methacrylate, and octadecyl acrylate.

[0079] In some embodiments, the flame-retardant filler comprises one or more of aluminum hydroxide, zinc borate, and aluminum hypophosphite. Optionally, the particle size D50 of the flame-retardant filler is 1 μm to 10 μm, and the surface is treated with a silane coupling agent. Specifically, the particle size D50 of the flame-retardant filler includes, but is not limited to: 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or any range between the foregoing.

[0080] In some embodiments, the adhesion promoter includes one or more of silanes, phosphates, and titanates.

[0081] In some embodiments, the initiator includes one or more of ammonium persulfate, sodium persulfate, and potassium persulfate. Further, optionally, the amount of the initiator is 0.3% to 1% of the total weight of the acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer.

[0082] In some embodiments, the acrylate copolymer emulsion comprises, by weight, the following raw material components:

[0083] The acrylate monomer is 30 to 90 parts.

[0084] The alkyl ester monomer is 5 to 35 parts.

[0085] The nitrogen-containing monomer is 2 to 20 parts.

[0086] The phosphorus-containing monomer is 0.1 to 20 parts.

[0087] The phosphorus-containing anionic emulsifier is 0.1 to 20 parts, and,

[0088] The nitrogen-containing nonionic emulsifier is 0.1 to 20 parts.

[0089] Specifically, the weight parts of the acrylate monomer include, but are not limited to: 30 parts, 35 parts, 40 parts, 45 parts, 46 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, or any range between the two mentioned above.

[0090] Specifically, the weight parts of the alkyl ester monomer include, but are not limited to: 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, or any two of the foregoing.

[0091] Specifically, the weight parts of the nitrogen-containing monomers include, but are not limited to: 2 parts, 5 parts, 7 parts, 10 parts, 12 parts, 13 parts, 15 parts, 17 parts, 20 parts, or any two of the foregoing.

[0092] Specifically, the weight parts of the phosphorus-containing monomer include, but are not limited to: 0.1 parts, 1 part, 3 parts, 6 parts, 8 parts, 10 parts, 13 parts, 15 parts, 17 parts, 20 parts, or any range between the two mentioned above.

[0093] Specifically, the phosphorus-containing anionic emulsifier may be present in parts by weight, including but not limited to: 0.1 parts, 1 part, 3 parts, 6 parts, 8 parts, 10 parts, 13 parts, 15 parts, 17 parts, 20 parts, or any combination thereof.

[0094] Specifically, the nitrogen-containing nonionic emulsifier is present in parts by weight, including but not limited to: 0.1 parts, 0.3 parts, 3 parts, 6 parts, 8 parts, 10 parts, 13 parts, 15 parts, 17 parts, 20 parts, or any combination thereof.

[0095] In some embodiments, the polyacrylate coating has the following characteristics:

[0096] (1) The loss factor (tanδ) is ≥0.2 in the temperature range of -30℃ to 110℃, and can be selected as ≥0.3;

[0097] (2) Limiting oxygen index (LOI) ≥22%, can be selected as ≥32%;

[0098] (3) If the UL94 vertical flammability rating is below V-2, it can be selected as below V-1.

[0099] Other embodiments of this application provide a method for preparing the polyacrylate coating, comprising the following steps:

[0100] The phosphorus-containing anionic emulsifier was mixed with water to prepare an aqueous phase;

[0101] The acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer are mixed to prepare an oil phase;

[0102] The oil phase is added to the aqueous phase for pre-emulsification to prepare a pre-emulsion.

[0103] The nitrogen-containing nonionic emulsifier is mixed with water to prepare a mixture;

[0104] A portion of the pre-emulsion, the mixture, and a portion of the initiator are mixed and emulsified to prepare a seed emulsion.

[0105] The seed emulsion is mixed with the remaining pre-emulsion and the remaining initiator, and then matured to prepare the acrylate copolymer emulsion.

[0106] The acrylic copolymer emulsion is mixed with the flame retardant filler, the adhesion promoter and the water to prepare the polyacrylate coating.

[0107] Without limitation, the amount of water added during the preparation of the aqueous phase and the preparation of the mixture can be adjusted according to the state of the aqueous phase and the mixture, with the aim of dispersing the phosphorus-containing anionic emulsifier and the nitrogen-containing nonionic emulsifier.

[0108] Furthermore, during the emulsification process:

[0109] The term "pre-emulsion" refers to 2% to 10% of the total mass of the pre-emulsion.

[0110] The term "initiator" in this context refers to 30% to 50% of the total mass of the initiator.

[0111] The emulsification conditions include a temperature of 75°C to 90°C and a time of 10 min to 30 min. Specifically, the temperature includes, but is not limited to, 75°C, 80°C, 85°C, 90°C or any two of the above; the time includes, but is not limited to, 10 min, 15 min, 20 min, 25 min, 30 min or any two of the above.

[0112] Furthermore, during the ripening process: maintain the temperature at 75℃~90℃, add the remaining pre-emulsion and the remaining initiator to the seed emulsion in batches over 2h~4h, and continue to keep warm for 2h~3h.

[0113] Furthermore, after aging, the reaction system is cooled to below 40°C, and then the flame-retardant filler and the adhesion promoter are added and mixed.

[0114] In other embodiments of this application, a battery is provided, including a battery pack and a housing, the battery pack being housed within the housing, the inner surface of the housing being provided with a coating formed by curing a polyacrylate coating as described above.

[0115] Furthermore, the thickness of the coating is 0.2 mm to 1 mm.

[0116] Furthermore, the curing conditions include: a temperature of 80℃~120℃ and a time of 10min~30min;

[0117] Without limitation, the housing is made of aluminum alloy, galvanized steel or engineering plastic.

[0118] Other embodiments of this application provide an electrical device, including a battery as described above.

[0119] Without limitation, the electrical device includes a vehicle.

[0120] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0121] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0122] The raw materials or reagents used in the embodiments and comparative examples of this application are shown in Table 1. Unless otherwise specified, other raw materials or reagents are commercially available products.

[0123] Table 1

[0124]

[0125] Examples 1-6 and Comparative Examples 1-4

[0126] (1) Prepare the acrylate copolymer emulsion according to the ingredients in Table 2 (parts by weight):

[0127] Table 2

[0128]

[0129] Note: Comparative Example 3 uses an equal amount of sodium dodecyl sulfate (SDS) instead of RS910, and adds 10 parts of ammonium polyphosphate (APP) as a flame retardant.

[0130] (2) Mix RS910 with an appropriate amount of water to prepare an aqueous phase;

[0131] (3) Mix LA, SA, AM, DAAM, PAEP and MMA to prepare the oil phase;

[0132] (4) The oil phase is slowly added to the aqueous phase and pre-emulsified under stirring to prepare a pre-emulsion;

[0133] (5) Mix SF-561 with an appropriate amount of water to prepare a mixture;

[0134] (6) Mix 5% of the total mass of the pre-emulsion with the mixture, heat to 85°C under nitrogen protection, then add 40% of the total mass of APS (in solution form, with water as solvent and a concentration of 5wt%) and mix. React and emulsify for 15 minutes to form a seed emulsion.

[0135] (7) The remaining pre-emulsion and the remaining initiator were added dropwise to the seed emulsion simultaneously within 3 hours, and the mixture was kept at 85°C for 2 hours to prepare the acrylate copolymer emulsion.

[0136] (8) Cool the acrylic copolymer emulsion to 40°C, add 15 parts of modified aluminum hydroxide, 3 parts of KH560 and 42 parts of water to 40 parts of acrylic copolymer emulsion, disperse evenly and discharge to obtain the coating.

[0137] The coating preparation methods of Examples 7 and 8 are the same as those of Example 1, the main difference being that the weight parts of the acrylate copolymer emulsion, flame retardant filler and adhesion promoter are different, as shown in Table 3 (parts by weight) below.

[0138] Table 3

[0139]

[0140] Test example:

[0141] The coating was sprayed onto an aluminum plate (150×70×1 mm) and baked at 120℃ for 20 minutes, resulting in a dry film thickness of 0.5 mm.

[0142] Test method:

[0143] (1) Damping performance: Refer to GB / T 18258-2000 "Test method for damping performance of damping materials", which is equivalent to ASTM E756 standard and is applicable to the determination of vibration damping characteristics.

[0144] (2) Flame retardant performance: Refer to GB 8624-2012 "Classification of Combustion Performance of Building Materials and Products", B1 level flame retardant requirement, which is compatible with the safety standards for flammable base materials in automobiles.

[0145] (3) Mechanical properties: The elongation at break is in accordance with GB / T 16777-2023 "Test Methods for Waterproof Coatings for Buildings".

[0146] (5) Adhesion test refers to GB / T 9286-2021 "Paints and Varnishes Cross-cut Test".

[0147] The test results are shown in Table 4 below:

[0148] Table 4

[0149]

[0150] In addition, the coating of Example 1 was sprayed onto the casing (aluminum alloy) of a certain type of ternary lithium battery pack and baked at 120°C for 20 minutes, with a dry film thickness of 0.5 mm.

[0151] Tests show that:

[0152] Vibration attenuation rate: The vibration transmissibility in the Y direction (main vibration direction) of the battery pack decreases by 15 dB at 100 Hz;

[0153] Thermal runaway protection: When needle penetration triggers thermal runaway of a single unit, the coating expands and foams to form a 2.3 mm carbon layer, preventing the flame from spreading to adjacent modules;

[0154] Salt spray aging: After 1000 hours of salt spray testing, the coating showed no blistering or peeling, and the adhesion remained at level 0.

[0155] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A polyacrylate coating, characterized in that, By weight, it comprises the following raw material components: 30-70 parts of acrylate copolymer emulsion 10 to 25 parts of flame retardant filler Adhesion promoter 0.5 to 5 parts, and 10 to 45 parts water; The acrylate copolymer emulsion is prepared by emulsion copolymerization of acrylate monomers, alkyl ester monomers, nitrogen-containing monomers and phosphorus-containing monomers in the presence of an initiator. The emulsifiers used in the emulsion copolymerization include phosphorus-containing anionic emulsifiers and nitrogen-containing nonionic emulsifiers. The alkyl chain length in the alkyl ester monomer is C10~C18.

2. The polyacrylate coating according to claim 1, characterized in that, The phosphorus-containing anionic emulsifier includes one or more of alkyl phosphates, polyoxyethylene phosphates, and fatty alcohol polyoxyethylene phosphates.

3. The polyacrylate coating according to claim 1, characterized in that, The nitrogen-containing nonionic emulsifier includes one or more of alkyl isopropanol amide and amino oleate.

4. The polyacrylate coating according to claim 1, characterized in that, The nitrogen-containing monomers include one or more of acrylamide monomers and acrylonitrile monomers; Optionally, the nitrogen-containing monomer includes one or more of acrylamide, methacrylamide, N-hydroxymethylacrylamide, acrylonitrile, and diacetone acrylamide.

5. The polyacrylate coating according to claim 1, characterized in that, The phosphorus-containing monomer includes one or more of the organic phosphate ester monomers; Optionally, the phosphorus-containing monomer includes one or more of styrene phosphate, diethyl vinyl phosphate, and 2-acrylamidoethyl phosphate.

6. The polyacrylate coating according to claim 1, characterized in that, The acrylate monomers include one or more selected from methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and isooctyl methacrylate; and / or, The alkyl chain in the alkyl ester monomer has a C12-C18 length and optionally includes unsaturated double bonds. Further optionally, the alkyl ester monomer includes one or more of lauryl acrylate, lauryl methacrylate, and octadecyl acrylate; and / or, The flame-retardant filler includes one or more of aluminum hydroxide, zinc borate, and aluminum hypophosphite. Optionally, the particle size D50 of the flame-retardant filler is 1 μm to 10 μm, and the surface is treated with a silane coupling agent; and / or, The adhesion promoter includes one or more of silanes, phosphates, and titanates; and / or, The initiator includes one or more of ammonium persulfate, sodium persulfate, and potassium persulfate; Optionally, the amount of the initiator is 0.3% to 1% of the total weight of the acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer.

7. The polyacrylate coating according to any one of claims 1 to 6, characterized in that, The acrylate copolymer emulsion comprises the following raw material components in parts by weight: The acrylate monomer is 30 to 90 parts. The alkyl ester monomer is 5 to 35 parts. The nitrogen-containing monomer is 2 to 20 parts. The phosphorus-containing monomer is 0.1 to 20 parts. The phosphorus-containing anionic emulsifier is 0.1 to 20 parts, and, The nitrogen-containing nonionic emulsifier is 0.1 to 20 parts.

8. The method for preparing the polyacrylate coating according to any one of claims 1 to 7, characterized in that, Includes the following steps: The phosphorus-containing anionic emulsifier was mixed with water to prepare an aqueous phase; The acrylate monomer, the alkyl ester monomer, the nitrogen-containing monomer, and the phosphorus-containing monomer are mixed to prepare an oil phase; The oil phase is added to the aqueous phase for pre-emulsification to prepare a pre-emulsion. The nitrogen-containing nonionic emulsifier is mixed with water to prepare a mixture; A portion of the pre-emulsion, the mixture, and a portion of the initiator are mixed and emulsified to prepare a seed emulsion. The seed emulsion is mixed with the remaining pre-emulsion and the remaining initiator, and then matured to prepare the acrylate copolymer emulsion. The acrylic copolymer emulsion is mixed with the flame retardant filler, the adhesion promoter and the water to prepare the polyacrylate coating.

9. A battery, characterized in that, The device includes a battery pack and a housing, the battery pack being housed within the housing, and the inner surface of the housing being provided with a coating, the coating being formed by curing a polyacrylate coating according to any one of claims 1 to 7; Optionally, the thickness of the coating is 0.2 mm to 1 mm; Optionally, the curing conditions include: a temperature of 80℃~120℃ and a time of 10min~30min; Optionally, the housing may be made of aluminum alloy, galvanized steel, or engineering plastic.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 9; Optionally, the electrical device includes a vehicle.

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