Insulating paint for automobile battery shell as well as preparation method and spraying method of insulating paint

Abstract

The invention relates to an insulating coating for an automobile battery shell as well as a preparation method and a spraying method of the insulating coating. The insulating coating comprises base resin, a curing agent and a diluent in a weight ratio of 6: 1: (1-1.5). A polyhydrocarbon substituted amine ion compound is introduced into the base resin, so that the antistatic property of the coating is effectively improved, and the insulation resistance is improved; by compounding two bisphenol A type liquid epoxy resins, the toughness of the coating is effectively enhanced, and the adhesive force and drawing force of the coating to a base material are improved; and the composite corrosion inhibitor is added to generate a synergistic effect with zinc phosphate and aluminum triphosphate, so that the corrosion resistance of the coating is greatly improved. According to the preparation method, the stability of the insulating paint is ensured through step-by-step feeding and process parameter control; the spraying method ensures that the coating is uniform and compact through accurate proportioning and viscosity control. The problem that an existing insulating layer is insufficient in electrolyte resistance and flame retardance is solved, short-circuit fire can be effectively prevented when the battery leaks, and the safe escape time is remarkably prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile battery safety protection, and particularly relates to an automobile battery shell insulating coating, a preparation method and a spraying method thereof. BACKGROUND

[0002] The power battery pack of a new energy vehicle is usually located at the bottom of the vehicle. The metal shell thereof not only needs to cope with a complex and harsh corrosion environment, but also must have high electrical insulation to prevent the risk of electric leakage and short circuit.

[0003] The prior art usually insulates the automobile battery shell by, for example, spraying a common insulating coating or pasting an insulating film. These existing insulating layers often focus on single insulation performance, and have insufficient electrolyte resistance and generally lack effective active flame retardant function. When the vehicle is involved in a collision and electrolyte leakage occurs, the electrolyte is prone to penetrate or corrode the original insulating layer, causing the electrolyte to directly contact the metal shell of the battery, resulting in shell corrosion and triggering short circuit and thermal runaway, which in turn leads to battery fire or even explosion, and cannot provide sufficient safe escape time for the people in the vehicle, which poses a major safety hazard. SUMMARY

[0004] The present application provides an automobile battery shell insulating coating, a preparation method and a spraying method thereof to solve the technical problem that the insulating coating in the prior art only forms an insulating layer on the battery shell, cannot completely prevent electrolyte from contacting the metal shell of the battery, is prone to cause short circuit and fire, and cannot provide sufficient safe escape time.

[0005] The present application provides an automobile battery shell insulating coating, a preparation method and a spraying method thereof to solve the technical problem that the insulating coating in the prior art only forms an insulating layer on the battery shell, cannot completely prevent electrolyte from contacting the metal shell of the battery, is prone to cause short circuit and fire, and cannot provide sufficient safe escape time. The base resin comprises at least the following components in the following weight percentages: 27-35% of bisphenol A type liquid epoxy resin, 0.5-0.8% of dispersant, 0.8-1% of polyamide wax, 13-20% of dimethylbenzene, 2-3% of n-butanol, 2-3% of ethylene glycol monobutyl ether, 0.5-0.8% of carbon black, 10-15% of zinc phosphate, 8-12% of aluminum tripolyphosphate, 4-6% of barium sulfate, 2-3% of insulating polymer, 10-15% of flame retardant, 0.8-1.2% of bentonite, 0.1-0.2% of defoaming agent, and 1-5% of adhesion promoter.

[0006] In one of the embodiments, the base resin comprises the following weight percentages of each component: liquid bisphenol A type epoxy resin 30-35%, dispersing agent 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 0.5-1%, polysiloxane compound adhesion promoter 0.5-1%; or The base resin comprises the following weight percentages of each component: liquid bisphenol A type epoxy resin 30-35%, dispersing agent 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, polyhydrocarbon-substituted amine ion complex 1-2%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 1.5-2.5%, polysiloxane compound adhesion promoter 1.5-2.5%; or The base resin comprises the following weight percentages of each component: first liquid bisphenol A type epoxy resin 12-15%, second liquid bisphenol A type epoxy resin 15-20%, dispersing agent 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, polyhydrocarbon-substituted amine ion complex 1-2%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 1.5-2.5%, polysiloxane compound adhesion promoter 1.5-2.5%; or The base resin comprises the following weight percentages of each component: 12-15% of a first bisphenol A type liquid epoxy resin, 15-20% of a second bisphenol A type liquid epoxy resin, 0.5-0.8% of a dispersing agent, 0.8-1% of a polyamide wax, 13-20% of dimethylbenzene, 2-3% of n-butanol, 2-3% of ethylene glycol monobutyl ether, 0.5-0.8% of carbon black, 10-15% of zinc phosphate, 8-12% of aluminum tripolyphosphate, 4-6% of barium sulfate, 2-3% of an insulating polymer, 1-2% of a polyhydrocarbon-substituted amine ionic complex, 10-15% of a flame retardant, 0.8-1.2% of bentonite, 0.1-0.2% of a defoaming agent, 0.1-0.2% of a composite corrosion inhibitor, 1.5-2.5% of an epoxy phosphate adhesion promoter, and 1.5-2.5% of a polysiloxane compound adhesion promoter.

[0007] In one of the embodiments, the curing agent comprises the following weight percentages of each component: 15-22% of trimethylbenzene, 10-16% of n-butanol, 60-70% of a polyamide curing agent, 0.5-0.8% of a reaction promoter, and 2-4% of a silane coupling agent.

[0008] In one of the embodiments, the diluent comprises the following weight percentages of each component: 15-20% of dimethylbenzene, 45-50% of trimethylbenzene, 10-15% of ethylene glycol monobutyl ether, and 20-25% of n-butanol.

[0009] The application also discloses a method for preparing the automobile battery shell insulating coating. S1, mixing, stirring and heating a bisphenol A type liquid epoxy resin, a dispersing agent and a polyamide wax to obtain a first slurry; S2, adding uniformly mixed n-butanol and part of dimethylbenzene into the first slurry and fully stirring to obtain a second slurry; S3, adding ethylene glycol monobutyl ether, carbon black, zinc phosphate, aluminum tripolyphosphate, barium sulfate, an insulating polymer, a flame retardant, bentonite and the rest of dimethylbenzene into the second slurry, uniformly mixing and stirring to obtain a mixed slurry, and then grinding the mixed slurry to obtain a third slurry; S4, adding a defoaming agent and an adhesion promoter into the third slurry and uniformly stirring to obtain a base resin; S5, mixing the base resin, a curing agent and a diluent according to a preset ratio to obtain the insulating coating.

[0010] In one of the embodiments, after step S4, the method further comprises: S41, inspecting the base resin, and packaging the base resin after passing the inspection.

[0011] In one of the embodiments, the viscosity of the mixed slurry is 110-130 Ku / 50-55℃ in step S3; and / or In step S4, the viscosity of the base resin is 113-120 Ku / 25℃, and the filtration fineness is 80-120 um.

[0012] In one of the embodiments, a polyhydrocarbon-substituted amine ionic complex is further added in step S3; or In step S3, a polyhydrocarbon-substituted amine ionic complex and a complex corrosion inhibitor are further added.

[0013] In one of the embodiments, the adhesion promoter is a mixture of an epoxy phosphate adhesion promoter and a polysiloxane compound adhesion promoter.

[0014] The application also discloses a method for spraying the automobile battery shell insulating coating. Coating preparation: adjust the insulating coating to a preset spraying viscosity; Substrate pretreatment: polish the substrate and clean the surface with a solvent; Spraying: spray the coating on the pretreated substrate surface to form a coating; Leveling and curing: level the sprayed workpiece, and then perform curing treatment to obtain a dry insulating coating.

[0015] The automobile battery shell insulating coating, the preparation method and the spraying method have the following beneficial effects: 1. The automobile battery shell insulating coating provided by the application significantly improves the adhesion, insulating performance and corrosion resistance of the insulating coating by introducing key raw material components such as a polyhydrocarbon-substituted amine ionic complex, a complex corrosion inhibitor and two kinds of bisphenol A type liquid epoxy resins, and has excellent flame retardant properties, thereby effectively preventing the contact between electrolyte and the metal shell when the battery is damaged, preventing thermal runaway, and prolonging the safety time for emergency escape.

[0016] 2. The preparation method provided by the application ensures the sufficient wetting and dispersion of each component and avoids powder agglomeration by a specific order of mixing the bisphenol A type liquid epoxy resin, the dispersant and the polyamide wax, heat preservation, then adding the solvent, and finally adding the powder and the additive; the viscosity is accurately adjusted to 113-120 Ku / 25℃, and the fineness is controlled to ≤60 um by controlling the rotation speed and time of high-speed and medium-speed dispersion, thereby ensuring that the prepared coating has excellent storage stability and construction applicability, and providing a fundamental guarantee for the consistency and reliability of the final coating performance.

[0017] 3、The spraying method provided by the present application, by setting the base resin, the curing agent and the diluent to be mixed in the accurate weight ratio of 6:1:(1~1.5), and controlling the construction viscosity at 40~42 seconds (4# cup, 20℃), ensures that the paint has good atomization effect and leveling property in the airless spraying or air spraying process, so as to form a wet film with uniform thickness and no defects; in combination with the set leveling time and curing conditions, the coating can finally reach the required performance indicators, and successfully realizes complete, dense and consistent performance insulation and corrosion prevention coating on the surface of the battery shell. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which:

[0019] Figure 1 is a flow chart of the preparation method of the automobile battery shell insulation paint of the present application; Figure 2 is a flow chart of the spraying method of the automobile battery shell insulation paint of the present application. DETAILED DESCRIPTION

[0020] In order to make the above objects, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0021] The present application discloses an automobile battery shell insulation paint, which is used for spraying on the surface of an automobile battery shell to form a corrosion-resistant insulation coating. The battery shell is a metal shell of a battery. When the battery is accidentally damaged and the electrolyte leaks, the insulation coating can act as a physical barrier to prevent the electrolyte from directly contacting the metal shell of the battery and causing short circuit and fire, thereby effectively preventing fire and prolonging the safe escape time.

[0022] Specifically, the insulation paint comprises base resin, curing agent and diluent in a weight ratio of 6:1:(1~1.5).

[0023] The base resin comprises at least the following components by weight percentage: 27-35% bisphenol A type liquid epoxy resin, 0.5-0.8% dispersant, 0.8-1% polyamide wax, 13-20% xylene, 2-3% n-butanol, 2-3% ethylene glycol monobutyl ether, 0.5-0.8% carbon black, 10-15% zinc phosphate, 8-12% aluminum tripolyphosphate, 4-6% barium sulfate, 2-3% insulating polymer, 10-15% flame retardant, 0.8-1.2% bentonite, 0.1-0.2% defoamer, and 1-5% adhesion promoter.

[0024] It should be noted that bisphenol A type liquid epoxy resin, as the main film-forming substance, provides the coating with basic adhesion, mechanical strength, and salt spray resistance. Dispersants are used to grind and disperse various powders in the resin system to form a uniform slurry. Polyamide wax and bentonite are used together to form an anti-settling system, preventing pigment and filler sedimentation during storage and ensuring product storage stability. Solvents such as xylene, n-butanol, and ethylene glycol monobutyl ether are used to adjust the viscosity of the base resin, ensuring good leveling properties and application adaptability. Carbon black provides the coating's hiding power. Zinc phosphate and aluminum tripolyphosphate, as active anti-rust pigments, can form a dense passivation protective layer on the metal substrate surface, thereby ensuring the coating's long-term salt spray resistance and effectively improving its corrosion resistance. Barium sulfate, as a functional filler, provides filling performance, effectively improving the coating's density and abrasion resistance. Insulating polymers provide high temperature resistance, heat resistance, and a high dielectric constant, effectively improving the coating's breakdown voltage resistance and insulation reliability. Flame retardants provide the coating with excellent flame retardant properties. Defoamers are used to suppress and eliminate air bubbles during production and application, preventing coating defects. Adhesion promoters are used to improve the adhesion between the coating and the substrate, and to enhance the coating's water resistance and salt spray resistance.

[0025] Furthermore, the curing agent comprises the following components in weight percentages: 15-22% trimethylbenzene, 10-16% n-butanol, 60-70% polyamide curing agent, 0.5-0.8% reaction accelerator, and 2-4% silane coupling agent.

[0026] It should be noted that the polyamide curing agent is used to crosslink with the epoxy groups in the base resin to form a three-dimensional network structure. By adjusting the ratio to increase the crosslinking density, the salt spray resistance and mechanical strength of the coating are directly enhanced. The reaction accelerator is used to improve curing efficiency and ensure that the coating can be fully cured under various application conditions. The silane coupling agent is used to further enhance the interfacial adhesion between the cured coating and the substrate. The reaction accelerator can be either Huntsman's Accelerator 2950 or Accelerator 960-1.

[0027] Further, the diluent includes the following weight percentages of each component: xylene 15-20%, trimethylbenzene 45-50%, ethylene glycol monobutyl ether 10-15%, n-butanol 20-25%.

[0028] It should be noted that the solvents such as xylene, trimethylbenzene, ethylene glycol monobutyl ether and n-butanol are used to precisely adjust the paint to the best spraying viscosity before construction.

[0029] The composition of the automobile battery shell insulating paint of the present application is described below in combination with specific examples.

[0030] Example 1 In this example, the base resin includes the following weight percentages of each component: bisphenol A type liquid epoxy resin 30-35%, dispersant 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 0.5-1%, polysiloxane compound adhesion promoter 0.5-1%; the curing agent includes the following weight percentages of each component: trimethylbenzene 18-22%, n-butanol 12-16%, polyamide curing agent 60-65%, reaction promoter 0.5-0.8%, silane coupling agent 2-4%; the diluent includes the following weight percentages of each component: xylene 15-20%, trimethylbenzene 45-50%, ethylene glycol monobutyl ether 10-15%, n-butanol 20-25%.

[0031] It should be noted that the epoxy phosphate adhesion promoter and the polysiloxane compound adhesion promoter are both used to improve the adhesion of the coating to the substrate, and simultaneously improve the water resistance and salt spray resistance of the coating.

[0032] Example 2 The base resin in this embodiment includes the following weight percentages of each component: liquid bisphenol A epoxy resin 30-35%, dispersant 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, polyhydrocarbon-substituted amine ionic complex 1-2%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 1.5-2.5%, polysiloxane compound adhesion promoter 1.5-2.5%; the curing agent includes the following weight percentages of each component: trimethylbenzene 15-18%, n-butanol 10-13%, polyamide curing agent 65-70%, reaction promoter 0.5-0.8%, silane coupling agent 2-4%; the diluent includes the following weight percentages of each component: xylene 15-20%, trimethylbenzene 45-50%, ethylene glycol monobutyl ether 10-15%, n-butanol 20-25%.

[0033] It should be noted that the polyhydrocarbon-substituted amine ionic complex is used to improve the antistatic properties of the coating, preventing the accumulation of electric charge, thereby increasing the insulation resistance.

[0034] Example 3 The base resin in this embodiment includes the following weight percentages of each component: first liquid bisphenol A epoxy resin 12-15%, second liquid bisphenol A epoxy resin 15-20%, dispersant 0.5-0.8%, polyamide wax 0.8-1%, xylene 13-20%, n-butanol 2-3%, ethylene glycol monobutyl ether 2-3%, carbon black 0.5-0.8%, zinc phosphate 10-15%, aluminum tripolyphosphate 8-12%, barium sulfate 4-6%, insulating polymer 2-3%, polyhydrocarbon-substituted amine ionic complex 1-2%, flame retardant 10-15%, bentonite 0.8-1.2%, defoaming agent 0.1-0.2%, epoxy phosphate adhesion promoter 1.5-2.5%, polysiloxane compound adhesion promoter 1.5-2.5%; the curing agent includes the following weight percentages of each component: trimethylbenzene 15-18%, n-butanol 10-13%, polyamide curing agent 65-70%, reaction promoter 0.5-0.8%, silane coupling agent 2-4%; the diluent includes the following weight percentages of each component: xylene 15-20%, trimethylbenzene 45-50%, ethylene glycol monobutyl ether 10-15%, n-butanol 20-25%.

[0035] It should be noted that the first type of bisphenol A liquid epoxy resin has a low molecular weight and viscosity, and is mainly responsible for ensuring good wettability and leveling of the coating on the substrate; the second type of bisphenol A liquid epoxy resin has a higher molecular weight, for example, E-20 type epoxy resin, which is mainly used to enhance the cohesive strength, toughness and crosslinking density of the cured coating. By compounding the second type of bisphenol A liquid epoxy resin with the first type of bisphenol A liquid epoxy resin, the difference in molecular weight or functionality is utilized to optimize the crosslinking network structure of the cured coating, thereby improving the toughness of the coating, and through the synergistic effect of the molecular chain, the adhesion and pull force of the coating on the substrate are improved, and the mechanical strength of the coating is further improved.

[0036] Example 4 In this embodiment, the base resin includes the following weight percentages of each component: the base resin is composed of the following weight percentages of each component: the first type of bisphenol A liquid epoxy resin 12-15%, the second type of bisphenol A liquid epoxy resin 15-20%, the dispersing agent 0.5-0.8%, the polyamide wax 0.8-1%, the xylene 13-20%, the n-butanol 2-3%, the ethylene glycol monobutyl ether 2-3%, the carbon black 0.5-0.8%, the zinc phosphate 10-15%, the aluminum tripolyphosphate 8-12%, the barium sulfate 4-6%, the insulating polymer 2-3%, the polyhydrocarbon-substituted amine ion complex 1-2%, the flame retardant 10-15%, the bentonite 0.8-1.2%, the defoaming agent 0.1-0.2%, the composite corrosion inhibitor 0.1-0.2%, the epoxy phosphate adhesion promoter 1.5-2.5%, the polysiloxane compound adhesion promoter 1.5-2.5%; the curing agent includes the following weight percentages of each component: the trimethylbenzene 15-18%, the n-butanol 10-13%, the polyamide curing agent 65-70%, the reaction promoter 0.5-0.8%, the silane coupling agent 2-4%; based on the total weight of the diluent, the diluent includes the following weight percentages of each component: the xylene 15-20%, the trimethylbenzene 45-50%, the ethylene glycol monobutyl ether 10-15%, the n-butanol 20-25%.

[0037] It should be noted that the composite corrosion inhibitor is used to produce a synergistic effect with zinc phosphate and aluminum tripolyphosphate, further enhancing the coating's ability to inhibit corrosion media and significantly improving the coating's corrosion resistance and salt spray resistance.

[0038] It has been found through testing that the insulating coating prepared from the raw material components of Example 1 has a pull force of 6.77 MPa, an insulating pressure resistance (leakage current) <2.5 mA, an insulating resistance of 1635 MΩ, a flame retardant level of V0, a dielectric strength of 35 KV / mm, and a neutral salt spray of 850 h. Among them, the pull force is not up to standard.

[0039] The insulation coating prepared from the raw material components of Example 2 has a pulling force of 7.02 MPa, an insulation withstand voltage (leakage current) <0.5 mA, an insulation resistance >4000 MΩ, a flame retardant level of V0, a dielectric strength of 37 KV / mm, and a neutral salt spray of 880 h. Compared with the raw material components of Example 1, when Example 2 is used: a multi-hydrocarbon substituted amine ion complex is added, which plays a synergistic catalytic role in the crosslinking and curing process of the bisphenol A type liquid epoxy resin and the curing agent, effectively enhances the insulation performance of the coating, greatly increases the insulation resistance from 1635 MΩ to >4000 MΩ, reduces the insulation withstand voltage (leakage current) from <2.5 mA to <0.5 mA, and increases the dielectric strength from 35 KV / mm to 37 KV / mm, forming a more solid electrical insulation barrier, thereby improving the antistatic property of the coating; by increasing the weight percentage of the epoxy phosphate adhesion promoter and the polysiloxane compound adhesion promoter, the adhesion of the coating to the substrate is effectively improved, the pulling force is increased from 6.77 MPa in Example 1 to 7.02 MPa, meeting the technical requirement of pulling force ≥7 MPa, ensuring the reliability of the coating combined with the battery shell; and by adjusting the proportion of each component of the curing agent, the crosslinking density is effectively improved, and the salt spray resistance is improved, with a neutral salt spray of 880 h from 850 h.

[0040] The insulation coating prepared from the raw material components of Example 3 has a pulling force of 8.89 MPa, an insulation withstand voltage (leakage current) <0.5 mA, an insulation resistance >4000 MΩ, a flame retardant level of V0, a dielectric strength of 48 KV / mm, and a neutral salt spray of 1100 h. Compared with the raw material components of Example 2, when Example 3 is used: the first bisphenol A type liquid epoxy resin and the second bisphenol A type liquid epoxy resin are compounded, the network crosslinking structure of the coating is optimized by the synergistic effect of two different molecular weights or functional epoxy resins, which has good wettability, cohesive strength and flexibility, the pulling force is further increased from 7.02 MPa in Example 2 to 8.89 MPa, showing better adhesion performance, the dielectric strength is greatly increased from 37 KV / mm to 48 KV / mm, and the insulation performance is more outstanding; the neutral salt spray test time reaches 1100 hours, which is about 30% higher than that of Example 1 and Example 2, effectively improving the long-term corrosion resistance of the coating.

[0041] The insulation coating prepared from the raw material components in Example 4 has a pulling force of 9.05 Mpa, an insulation withstand voltage (leakage current) <0.5 mA, an insulation resistance >4000 MΩ, a flame retardant level of V0, a dielectric strength of 51 KV / mm, and a neutral salt spray of 1440 h. Compared with the raw material components of Example 3, when Example 4 is used: a composite corrosion inhibitor is added, which can produce a synergistic effect with zinc phosphate and aluminum tripolyphosphate in the raw material components to form a more dense and stable passivation protective layer on the base surface of the metal shell, effectively delaying the penetration of corrosion medium and improving the corrosion resistance of the coating; the pulling force of 9.05 Mpa and the dielectric strength of 51 KV / mm both reach the highest values in all examples, providing the most reliable mechanical fixation and electrical insulation protection; the neutral salt spray test time reaches 1440 hours, which is nearly 70% higher than that of Example 1, and can maximize the long-term corrosion protection of the battery shell, fundamentally improving the safety and reliability of the battery.

[0042] For reference Figure 1 The application further discloses a method for preparing the insulation coating of the battery shell of the automobile. S1, mixing, stirring and heating a bisphenol A type liquid epoxy resin, a dispersing agent and a polyamide wax to obtain a first slurry; Specifically, first, 30-35% of the bisphenol A type liquid epoxy resin, 0.5-0.8% of the dispersing agent and 0.8-1% of the polyamide wax are added to a reaction kettle, mixed, stirred and dispersed at a rotation speed of 900-1500 r / min, heated and warmed to 60 DEG C, and then stirred and kept warm at a rotation speed of 600-900 r / min for 20-30 min to obtain the first slurry. Further preferably, first, 12-15% of the first bisphenol A type liquid epoxy resin, 15-20% of the second bisphenol A type liquid epoxy resin, 0.5-0.8% of the dispersing agent and 0.8-1% of the polyamide wax are added to a reaction kettle, mixed, stirred and dispersed at a rotation speed of 900-1500 r / min, heated and warmed to 60 DEG C, and then stirred and kept warm at a rotation speed of 600-900 r / min for 20-30 min to obtain the first slurry.

[0043] S2, adding uniformly mixed n-butanol and part of dimethylbenzene to the first slurry and fully stirring to obtain a second slurry; Specifically, 2-3% of the uniformly mixed n-butanol and 5-8% of the dimethylbenzene are added to the first slurry in the reaction kettle and fully stirred to obtain the second slurry.

[0044] S3, adding ethylene glycol monobutyl ether, carbon black, zinc phosphate, aluminum tripolyphosphate, barium sulfate, insulating polymer, flame retardant and bentonite and the rest of the xylene in the second slurry, mixing and stirring to disperse to obtain a mixed slurry, then grinding the mixed slurry to obtain a third slurry; Preferably, 2~3% ethylene glycol monobutyl ether, 0.5~0.8% carbon black, 10~15% zinc phosphate, 8~12% aluminum tripolyphosphate, 4~6% barium sulfate, 2~3% insulating polymer, 10~15% flame retardant, 0.8~1.2% bentonite are added to the second slurry in the reaction kettle, mixed uniformly and stirred to disperse at a speed of 600~900r / min, and the scraper is opened at the same time to stir and scrape, and after the above powders are added, the paint gauge is used to scrape the powders on the wall of the reaction kettle, then 8~12% xylene is added to clean the wall of the reaction kettle, finally stirring and dispersing at a speed of 900~1500r / min for about 20~30min to obtain a mixed slurry, then the mixed slurry is put into a sand mill for grinding until the grinding fineness is ≤60um to obtain a third slurry.

[0045] Further preferably, 2~3% ethylene glycol monobutyl ether, 0.5~0.8% carbon black, 10~15% zinc phosphate, 8~12% aluminum tripolyphosphate, 4~6% barium sulfate, 2~3% insulating polymer, 1~2% polyhydrocarbon-substituted amine ion complex, 10~15% flame retardant, 0.8~1.2% bentonite are added to the second slurry in the reaction kettle, mixed uniformly and stirred to disperse at a speed of 600~900r / min, and the scraper is opened at the same time to stir and scrape, and after the above powders are added, the paint gauge is used to scrape the powders on the wall of the reaction kettle, then 8~12% xylene is added to clean the wall of the reaction kettle, finally stirring and dispersing at a speed of 900~1500r / min for about 20~30min to obtain a mixed slurry, then the mixed slurry is put into a sand mill for grinding until the grinding fineness is ≤60um to obtain a third slurry.

[0046] Still further preferably, 2~3% ethylene glycol monobutyl ether, 0.5~0.8% carbon black, 10~15% zinc phosphate, 8~12% aluminum tripolyphosphate, 4~6% barium sulfate, 2~3% insulating polymer, 1~2% polyhydrocarbon-substituted amine ion complex, 10~15% flame retardant, 0.8~1.2% bentonite, 0.1~0.2% composite corrosion inhibitor are added to the second slurry in the reaction kettle, mixed uniformly and stirred to disperse at a speed of 600~900r / min, and the scraper is opened at the same time to stir and scrape, and after the above powders are added, the paint gauge is used to scrape the powders on the wall of the reaction kettle, then 8~12% xylene is added to clean the wall of the reaction kettle, finally stirring and dispersing at a speed of 900~1500r / min for about 20~30min to obtain a mixed slurry, then the mixed slurry is put into a sand mill for grinding until the grinding fineness is ≤60um to obtain a third slurry.

[0047] It should be noted that xylene is added twice in S2 and S3 as a solvent to more accurately control the viscosity of the second slurry and the third slurry, thereby optimizing the grinding dispersion efficiency and ensuring the stability of the final product. In this embodiment, the barium sulfate can be 3000 mesh barium sulfate; the insulating polymer is selected from at least one of polytetrafluoroethylene, polyamide-imide, and silazane polymer; the polyhydrocarbon-substituted amine ion complex includes but is not limited to quaternary ammonium salt antistatic agent; the flame retardant is selected from at least one of organic flame retardants such as phosphate ester, nitrogen system, or inorganic flame retardants such as magnesium hydroxide and zinc borate; the composite corrosion inhibitor is selected from at least one of Halox 550WF, Halox 515, Raybo-75, or Raybo-55.

[0048] Specifically, the viscosity of the mixed slurry is 110-130 Ku / 50-55℃. When the viscosity of the mixed slurry is less than 110 Ku / 50-55℃, after technical confirmation, 0.5-1.0% thickening agent is added for adjustment until the viscosity of the mixed slurry reaches a grindable state; when the viscosity of the mixed slurry is higher than 130 Ku / 50-55℃, the stirring time is extended by about 20-30 min until the viscosity of the mixed slurry reaches a grindable state; then the mixed slurry with a viscosity of a grindable state is put into a sand mill for grinding until the grinding fineness is ≤60 um.

[0049] S4, adding a defoaming agent and an adhesion promoter to the third slurry and stirring uniformly to obtain a base resin; Specifically, the adhesion promoter is a mixture of an epoxy phosphate adhesion promoter and a polysiloxane compound adhesion promoter. A defoaming agent 0.1-0.2%, an epoxy phosphate adhesion promoter 1.5-2.5%, and a polysiloxane compound adhesion promoter 1.5-2.5% are added to the third slurry in the reaction kettle and stirred uniformly to obtain the base resin.

[0050] S41, the base resin is inspected, and after passing the inspection, it is filtered and packaged.

[0051] Specifically, the viscosity of the base resin is 113-120 Ku / 25℃, and the filtering fineness is 80-120 um. When the viscosity of the base resin does not meet the standard, the viscosity can be adjusted by adding an appropriate amount of xylene, and after passing the inspection, it is filtered and packaged with a 80-120 um filter screen.

[0052] S5, mixing the base resin, the curing agent, and the diluent according to a preset ratio to obtain an insulating coating.

[0053] Specifically, the base resin, the curing agent, and the diluent are completely mixed in a ratio of 6:1:(1-1.5) by weight to obtain the insulating coating.

[0054] Please refer to Figure 2 The application further discloses a method for spraying an automobile battery shell with insulating paint. Paint preparation: adjust the insulating paint to a preset spraying viscosity.

[0055] Specifically, the insulating paint is obtained by completely mixing a base resin, a curing agent and a diluent at a weight ratio of 6:1:(1-1.5), and adjusting the viscosity of the insulating paint to 40-42s (cup-4# / 20 DEG C) by adding dimethylbenzene, so as to avoid high viscosity and facilitate spraying with a spray gun. The paint viscosity can be adjusted according to the actual coating effect; the diluent needs to be adjusted appropriately according to the change of the climate to ensure the coating quality.

[0056] Substrate pretreatment: polish the substrate and clean the surface with a solvent.

[0057] Specifically, the pretreatment includes polishing, dust removal and oil removal of the surface of the substrate to be sprayed. Specifically, the oil removal step can use a dust-free cloth to wipe, can use isopropyl alcohol to clean and remove oil, or can use other solvents with oil removal effect to remove oil, which is not limited here.

[0058] Spraying: spray the paint on the pretreated substrate surface to form a coating.

[0059] Specifically, the paint is sprayed using a spray gun to uniformly spray the paint on the pretreated substrate surface, and the spraying amount is controlled to form a coating with a thickness of 120-300μm. The spray gun mode can be selected from airless spraying and air spraying. The parameters of the airless spraying are set as follows: spraying air pressure 4-7kg / cm 2 , spray gun caliber 3.0mm; the parameters of the air spraying are set as follows: spraying air pressure 0.4-0.7MPa, spray gun caliber 3.0mm.

[0060] Leveling and curing: level the sprayed workpiece, and then perform curing treatment to obtain a dry insulating coating.

[0061] Specifically, the sprayed workpiece is leveled at room temperature for 10-15min, and then the workpiece is baked using an oven, the baking temperature is 80±5 DEG C, and the baking time is 40-60min, so that the paint is fixed on the surface of the sprayed workpiece and deposited on the surface of the workpiece, the adhesion between the paint and the product is improved, and finally the workpiece is cured at room temperature for more than 24h to obtain a dry insulating coating with a thickness of 120-300μm.

[0062] The automobile battery shell insulating coating and the preparation method and the spraying method thereof are prepared by using the preparation method, and the automobile battery shell insulating coating is prepared according to the raw material components of the examples 1 to 4.

[0063] The automobile battery shell insulating coating and the preparation method and the spraying method thereof are prepared by using the preparation method, and the automobile battery shell insulating coating is prepared according to the raw material components of the examples 1 to 4.

[0064] The technical features of the above-mentioned examples can be combined arbitrarily, and for the sake of brevity, all possible combinations of the technical features in the above-mentioned examples are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0065] The above-mentioned examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. An insulating coating for automotive battery casings, characterized in that, It includes a base resin, a curing agent, and a diluent in a weight ratio of 6:1:(1~1.5); wherein: The base resin comprises at least the following components by weight percentage: 27-35% bisphenol A type liquid epoxy resin, 0.5-0.8% dispersant, 0.8-1% polyamide wax, 13-20% xylene, 2-3% n-butanol, 2-3% ethylene glycol monobutyl ether, 0.5-0.8% carbon black, 10-15% zinc phosphate, 8-12% aluminum tripolyphosphate, 4-6% barium sulfate, 2-3% insulating polymer, 10-15% flame retardant, 0.8-1.2% bentonite, 0.1-0.2% defoamer, and 1-5% adhesion promoter.

2. The automotive battery casing insulating coating according to claim 1, characterized in that, The base resin comprises the following components in weight percentages: 30-35% bisphenol A type liquid epoxy resin, 0.5-0.8% dispersant, 0.8-1% polyamide wax, 13-20% xylene, 2-3% n-butanol, 2-3% ethylene glycol monobutyl ether, 0.5-0.8% carbon black, 10-15% zinc phosphate, 8-12% aluminum tripolyphosphate, 4-6% barium sulfate, 2-3% insulating polymer, 10-15% flame retardant, 0.8-1.2% bentonite, 0.1-0.2% defoamer, 0.5-1% epoxy phosphate adhesion promoter, and 0.5-1% polysiloxane compound adhesion promoter; or The base resin comprises the following components in weight percentages: 30-35% bisphenol A type liquid epoxy resin, 0.5-0.8% dispersant, 0.8-1% polyamide wax, 13-20% xylene, 2-3% n-butanol, 2-3% ethylene glycol monobutyl ether, 0.5-0.8% carbon black, 10-15% zinc phosphate, 8-12% aluminum tripolyphosphate, 4-6% barium sulfate, 2-3% insulating polymer, 1-2% polyhydrocarbon-substituted amine ion complex, 10-15% flame retardant, 0.8-1.2% bentonite, 0.1-0.2% defoamer, 1.5-2.5% epoxy phosphate adhesion promoter, and 1.5-2.5% polysiloxane compound adhesion promoter; or The base resin comprises the following components in weight percentages: 12-15% of a first type of bisphenol A liquid epoxy resin, 15-20% of a second type of bisphenol A liquid epoxy resin, 0.5-0.8% of a dispersant, 0.8-1% of a polyamide wax, 13-20% of xylene, 2-3% of n-butanol, 2-3% of ethylene glycol monobutyl ether, 0.5-0.8% of carbon black, 10-15% of zinc phosphate, 8-12% of aluminum tripolyphosphate, 4-6% of barium sulfate, 2-3% of an insulating polymer, 1-2% of a polyhydrocarbon-substituted amine ion complex, 10-15% of a flame retardant, 0.8-1.2% of bentonite, 0.1-0.2% of a defoamer, 1.5-2.5% of an epoxy phosphate adhesion promoter, and 1.5-2.5% of a polysiloxane compound adhesion promoter; or The base resin comprises the following components in weight percentages: 12-15% of a first type of bisphenol A liquid epoxy resin, 15-20% of a second type of bisphenol A liquid epoxy resin, 0.5-0.8% of a dispersant, 0.8-1% of a polyamide wax, 13-20% of xylene, 2-3% of n-butanol, 2-3% of ethylene glycol monobutyl ether, 0.5-0.8% of carbon black, 10-15% of zinc phosphate, 8-12% of aluminum tripolyphosphate, 4-6% of barium sulfate, 2-3% of an insulating polymer, 1-2% of a polyhydrocarbon-substituted amine ion complex, 10-15% of a flame retardant, 0.8-1.2% of bentonite, 0.1-0.2% of a defoamer, 0.1-0.2% of a composite corrosion inhibitor, 1.5-2.5% of an epoxy phosphate adhesion promoter, and 1.5-2.5% of a polysiloxane compound adhesion promoter.

3. The automotive battery casing insulating coating according to claim 1, characterized in that, The curing agent comprises the following components in weight percentages: 15-22% trimethylbenzene, 10-16% n-butanol, 60-70% polyamide curing agent, 0.5-0.8% reaction accelerator, and 2-4% silane coupling agent.

4. The automotive battery casing insulating coating according to claim 1, characterized in that, The diluent comprises the following components in weight percentages: xylene 15-20%, trimethylbenzene 45-50%, ethylene glycol monobutyl ether 10-15%, and n-butanol 20-25%.

5. A method for preparing the insulating coating for an automotive battery casing according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix and stir bisphenol A type liquid epoxy resin, dispersant and polyamide wax and heat and keep warm to obtain the first slurry; S2. Add the well-mixed n-butanol and part of xylene to the first slurry and stir thoroughly to obtain the second slurry; S3. Add ethylene glycol monobutyl ether, carbon black, zinc phosphate, aluminum tripolyphosphate, barium sulfate, insulating polymer, flame retardant, bentonite and the balance xylene to the second slurry, mix evenly and stir to disperse to obtain a mixed slurry, then grind the mixed slurry to obtain the third slurry; S4. Add defoamer and adhesion promoter to the third slurry and stir evenly to obtain the base resin; S5. Mix the base resin, curing agent and diluent according to the preset ratio to obtain the insulating coating.

6. The method according to claim 5, characterized in that, Step S4 is followed by: S41. The base resin is sent for testing, and after passing the test, it is filtered and packaged.

7. The method according to claim 5, characterized in that, In step S3, the sampling test viscosity of the mixed slurry is 110–130 Ku / 50–55 °C; and / or In step S4, the tested viscosity of the base resin is 113-120 Ku / 25℃, and the filtration fineness is 80-120 μm.

8. The method according to claim 5, characterized in that, In step S3, a polyhydrocarbon-substituted amine ion complex is also added; or In step S3, a polyhydrocarbon-substituted amine ion complex and a composite corrosion inhibitor are also added.

9. The method according to claim 5, characterized in that, The adhesion promoter is a mixture of epoxy phosphate adhesion promoter and polysiloxane compound adhesion promoter.

10. A method for spraying an insulating coating for an automotive battery casing according to any one of claims 1-4, characterized in that, Includes the following steps: Coating preparation: Adjust the insulating coating to the preset spraying viscosity; Substrate pretreatment: The substrate is sanded and the surface is cleaned by wiping with solvent; Spraying: Applying paint to the surface of a pretreated substrate to form a coating; Leveling and curing: The sprayed workpiece is leveled and then cured to obtain a dry insulating coating.

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