Corrosion-resistant and weather-resistant power battery cell lead terminal insulating glue and preparation method thereof

Abstract

The application discloses a corrosion-resistant and weather-resistant power battery cell lead terminal insulating glue and a preparation method thereof, and relates to the technical field of insulating glue.The corrosion-resistant and weather-resistant power battery cell lead terminal insulating glue is prepared by mixing component A and component B at a mass ratio of 95-105:10-30; the component A comprises the following raw materials in parts by weight: modified epoxy resin 40-60 parts; organic silicon toughening modifier 10-25 parts; active diluent 5-15 parts; corrosion-resistant functional filler 15-30 parts; coupling agent 1-3 parts; and weather-resistant additive 0.5-2 parts. The silane modified imidazole-epoxy adduct curing agent with a core-shell structure is constructed, the active center of imidazole is physically isolated at normal temperature, and the problems of short latent period and easy pre-curing of the traditional imidazole curing agent are effectively solved. This makes the insulating glue keep a low viscosity growth rate during long-term storage, and greatly prolongs the shelf life.

Description

Technical Field

[0001] This invention relates to the field of insulating adhesive technology, specifically to an insulating adhesive for the lead terminals of a power battery cell that is corrosion-resistant and weather-resistant, and its preparation method. Background Technology

[0002] With the rapid development of new energy vehicles, energy storage equipment, and other fields, the safety and lifespan of power batteries have become a core focus of the industry. As a key interface for energy transmission in power batteries, the insulation protection of the cell lead terminals directly affects the overall reliability of the battery pack. They need to withstand long-term temperature and humidity fluctuations, chemical corrosion, and ultraviolet radiation under complex operating conditions, which places stringent requirements on the corrosion resistance, weather resistance, and curing stability of the insulating adhesive.

[0003] As a core component of insulating adhesives, the performance of the curing agent directly determines the storage stability, curing efficiency, and final performance of the adhesive. Latent curing agents, due to their stability with the resin system at room temperature and rapid curing at high temperatures, have become the preferred type for power battery insulating adhesives. Imidazole-based curing agents have been widely studied due to their high curing activity and excellent mechanical properties of the cured products. However, traditional imidazole-based curing agents suffer from short latency periods and are prone to pre-reaction with epoxy resins at room temperature, leading to a shortened shelf life of the insulating adhesive and limiting their application in industrial production.

[0004] While existing amine-based latent curing agents can improve storage stability, the cured products lack sufficient corrosion resistance and weather resistance, making them prone to aging and cracking during long-term use of power batteries, potentially leading to insulation failure. Silane modification technology, which can introduce weather-resistant and corrosion-resistant siloxane structures, has been used to optimize curing agent performance. However, existing silane-modified curing agents generally suffer from poor compatibility with epoxy resins, easy aggregation during addition reactions, and insufficient interfacial bonding after curing, making it difficult to achieve a balance between latency, compatibility, and final protective performance.

[0005] To address the specific application requirements of insulating adhesives for power battery cell lead terminals, the development of a curing agent that combines long latency, excellent compatibility, and superior corrosion and weather resistance has become an urgent industry need. Silane-modified imidazole-epoxy adduct latent curing agents, through molecular structure design, combine the weather-resistant properties of silane, the high reactivity of imidazole, and the latency of epoxy adducts, potentially solving the technical pain points of existing curing agents. However, current curing agents still have shortcomings in terms of synthesis process optimization and precise performance control, and their application in power battery insulating adhesives has not yet achieved ideal results, requiring further improvement to meet industry development requirements. Summary of the Invention

[0006] The purpose of this invention is to address the problems of short curing time, poor storage stability, and insufficient corrosion and weather resistance of existing insulating adhesives for power battery cell lead terminals, which easily lead to insulation failure. This invention provides a corrosion- and weather-resistant insulating adhesive for power battery cell lead terminals and its preparation method. The adhesive uses a dedicated silane-modified imidazole-epoxy adduct latent curing agent to balance long storage time, high curing efficiency, and excellent protective performance, meeting the requirements of complex operating conditions in power batteries.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect protected by this application: a silane-modified imidazole-epoxy adduct latent curing agent, comprising the following steps:

[0009] A1. Synthesis of the binuclear imidazole intermediate: 2-Ethyl-4-methylimidazolium was dissolved in anhydrous ethanol or acetonitrile solvent, and an inorganic base was added as an acid-binding agent. 1,3-Dibromo-2-propanol was added dropwise under stirring, wherein the molar ratio of 2-ethyl-4-methylimidazolium to 1,3-dibromo-2-propanol was 2.0-2.2:1. After the addition was complete, the temperature was raised to 75-85℃ and refluxed for 10-12 hours. After the reaction was completed, the solvent was recovered by vacuum distillation, and the generated inorganic salt was removed by washing with water. After filtration, drying and recrystallization, 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol was obtained.

[0010] A2. Preparation of imidazole-epoxy adduct microcapsule core: 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol and bisphenol A type epoxy resin are mixed at a mass ratio of 1:3-5, heated to 90-110℃ and stirred at high speed until phase separation occurs in the reaction system and adduct solid particles precipitate out to form microcapsule core;

[0011] A3. In-situ silane surface grafting and shell construction: Cool the reaction system to 60-75℃, add γ-glycidoxypropyltrimethoxysilane to the suspended S2 product, the amount of which is 2wt%-6wt% of the total mass of the A2 system, and continue to keep warm and stir for 1-2 hours.

[0012] A4. Post-treatment and powdering: After the reaction in A3 is completed, the mixture is rapidly cooled to room temperature to terminate the reaction. A non-polar solvent is added to wash away unreacted liquid epoxy resin. The solid product is separated by filtration and then vacuum dried at 50°C and classified by air jet milling to obtain a silane-modified imidazole-epoxy adduct latent curing agent with an average particle size of 3-10 μm.

[0013] The nonpolar solvent is xylene or n-heptane.

[0014] Furthermore, by adopting the above technical solution, the reaction that occurs in A1 is an N-alkylation reaction.

[0015] By adopting the above technical solution, the inorganic base in A1 is any one of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0016] By adopting the above technical solution, the reaction process of A1 is further as follows:

[0017] ;

[0018] Compound 1 is 2-ethyl-4-methylimidazole;

[0019] Compound 2 is 1,3-dibromo-2-propanol;

[0020] Compound 3 is 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol, wherein compound 3 is a novel substance as of the date of filing of this application.

[0021] By adopting the above technical solution, the 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol is a binuclear imidazolium derivative. The active hydrogen is blocked by alkylation modification at the N1 position, achieving chemical inertness at room temperature. During use, heating causes the curing agent to transform from a crystalline state to a liquid state, releasing a high concentration of the tertiary amine active center at the N3 position. The hydroxyl group (-OH) introduced into the molecular backbone not only acts as an intramolecular proton donor, promoting the ring-opening reaction of the epoxy group and synergistically reducing the curing temperature, but also provides chemical grafting sites for subsequent silane surface coating.

[0022] The second aspect of this application is protected: a corrosion- and weather-resistant insulating adhesive for the lead terminals of a power battery cell, wherein the insulating adhesive is composed of component A and component B mixed in a mass ratio of 95-105:10-30;

[0023] Component A, by weight, comprises the following raw materials: 40-60 parts modified epoxy resin; 10-25 parts organosilicon toughening modifier; 5-15 parts reactive diluent; 15-30 parts corrosion-resistant functional filler; 1-3 parts coupling agent; and 0.5-2 parts weather-resistant additive.

[0024] Component B is a modified amine latent curing agent;

[0025] The modified amine latent curing agent is a silane-modified imidazole-epoxy adduct latent curing agent.

[0026] Furthermore, by adopting the above technical solution, the modified epoxy resin is a mixture of hydrogenated bisphenol A type epoxy resin and bisphenol F type epoxy resin, with a mass ratio of 1:(0.5-1.5).

[0027] By adopting the above technical solution, the epoxy equivalent of the hydrogenated bisphenol A type epoxy resin is further 180-220 g / eq.

[0028] Furthermore, by adopting the above technical solution, the organosilicon toughening modifier is any one of cyclodimethylsiloxane and polyether-modified silicone oil.

[0029] By adopting the above technical solution, the corrosion-resistant functional filler further includes one or more combinations of nano-silica, flake glass flakes, and nano-alumina that have undergone hydrophobic modification.

[0030] Furthermore, by adopting the above technical solution, the weather-resistant agent is further composed of hindered amine light stabilizer and benzotriazole ultraviolet absorber in a mass ratio of 1:1.

[0031] By adopting the above technical solution, the coupling agent is further selected from γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and vinyltriethoxysilane.

[0032] The third aspect protected by this application: a method for preparing a corrosion-resistant and weather-resistant insulating adhesive for the lead terminals of a power battery cell, comprising the following steps:

[0033] S1 packing pretreatment: The corrosion-resistant functional packing is dried at 100-120℃ for 2-4 hours, and the coupling agent is added and stirred for 2-3 hours to obtain the modified corrosion-resistant functional packing.

[0034] S2 resin blending: The modified epoxy resin and reactive diluent are added to a reaction vessel and mixed evenly at 40-60℃;

[0035] S3 Toughening and Dispersion: Add the organosilicon toughening modifier, modified corrosion-resistant functional filler and weather-resistant additive to the mixture in step S2, and perform high-speed shear dispersion at a speed of 1500-3000 rpm for 30-60 minutes.

[0036] S4 Grinding and Degassing: The mixed slurry obtained in step S3 is ground to a fineness of less than 20 μm using a three-roll mill, and then degassed under vacuum at a pressure of -0.09 MPa to -0.1 MPa to obtain component A;

[0037] S5 adhesive preparation: Mix component A and component B in the specified ratio before use, and apply after vacuum degassing.

[0038] By adopting the above technical solution, further, in S3, when adding the modified corrosion-resistant functional filler, a step-by-step feeding method is adopted, adding 1 / 3 of its total amount each time, and stirring for 10-15 minutes after each addition.

[0039] By adopting the above technical solution, further, in S4, the roller temperature of the three-roll mill is controlled at 25-35℃ to prevent the material from pre-curing due to frictional heat generation.

[0040] By adopting the above technical solution, the insulating adhesive is further applied to the junction of the tab metal strip and the aluminum-plastic film or tab adhesive, and the curing conditions are: pre-curing at 80°C for 30 minutes, followed by post-curing at 120-150°C for 60-90 minutes.

[0041] This invention achieves a high degree of synergy between latency, corrosion resistance and weather resistance by adjusting the mass ratio of component A to component B to 95-105:10-30 and utilizing the specific proportions of each mass part of raw materials. Component B serves as the core, employing a novel binuclear imidazole derivative to construct the microcapsule core. A shell is formed through in-situ surface grafting of 2%-6% silane. This unique core-shell structure physically isolates the imidazole active sites at room temperature, solving the problem of short latency in traditional imidazoles. Simultaneously, the binuclear structure released during high-temperature unsealing provides a high density of cross-linking points. When this curing agent undergoes a cross-linking reaction with the modified epoxy resin in component A, the organosilicon toughening modifier is interspersed within the network to reduce internal stress and prevent coating cracking. Combined with the corrosion-resistant functional filler and its excellent dispersibility after coupling agent treatment, a dense "maze effect" is constructed within the coating to block the penetration of corrosive media. Furthermore, weather-resistant additives specifically protect against ultraviolet radiation. Combined with weather-resistant siloxane segments introduced by silane bonds on the curing agent surface, this effectively compensates for the poor weather resistance of amine curing agents. Thus, while ensuring long-term storage stability, the insulating adhesive ultimately possesses excellent resistance to high-temperature and high-humidity aging and ultraviolet radiation, meeting the stringent operating requirements of power batteries.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. By constructing a silane-modified imidazole-epoxy adduct curing agent with a "core-shell structure," the active center of imidazole is physically isolated at room temperature, effectively solving the problems of short latency and easy pre-curing of traditional imidazole curing agents. This allows the insulating adhesive to maintain a low viscosity growth rate during long-term storage, greatly extending its pot life.

[0044] 2. A dense protective network is constructed by utilizing the "labyrinth effect" formed by corrosion-resistant fillers (such as glass flakes) and the UV resistance introduced by silane bonds and weather-resistant additives. Compared with existing technologies, this insulating adhesive exhibits superior resistance to corrosion and aging under harsh conditions such as high-temperature electrolyte immersion and UV irradiation.

[0045] 3. By introducing an organosilicon toughening modifier interspersed within the crosslinking network, the internal stress during epoxy resin curing is effectively reduced, preventing coating cracking. This results in the cured adhesive layer not only possessing higher initial shear bond strength but also maintaining a high strength retention rate after long-term aging tests, overcoming the defects of traditional amine-cured products being brittle and prone to cracking. Attached Figure Description

[0046] Figure 1 The above is the 1H NMR spectrum of 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol of this invention.

[0047] Figure 2 The infrared spectrum of the silane-modified imidazole-epoxy adduct latent curing agent of the present invention is shown. Detailed Implementation

[0048] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Preparation Example 1

[0050] Preparation of silane-modified imidazole-epoxy adduct latent curing agent:

[0051] A1: Synthesis of binuclear imidazole intermediates:

[0052] ;

[0053] In a three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a thermometer, add 5.0 g of 2-ethyl-4-methylimidazole and dissolve it in 40 mL of acetonitrile solvent. Subsequently, 6.9 g of anhydrous potassium carbonate was added as an acid-binding agent, and stirring was started. 4.7 g of 1,3-dibromo-2-propanol (the molar ratio of 2-ethyl-4-methylimidazolium to 1,3-dibromo-2-propanol was approximately 2.1:1) was weighed and dissolved in 10 mL of acetonitrile. The solution was placed in a constant pressure dropping funnel and slowly added dropwise to the reaction flask at room temperature over a period of 30 minutes. After the addition was complete, the temperature was slowly raised to 80 °C and refluxed for 12 hours. After the reaction was completed, the acetonitrile solvent was removed by rotary evaporation. 50 mL of deionized water was added to the residue, and the mixture was stirred and washed to remove the generated potassium bromide inorganic salt. The residue was filtered, and the filter cake was recrystallized in an ethyl acetate / n-hexane system (ethyl acetate:n-hexane = 1:1.5). After vacuum drying at 60 °C, 5.8 g of the intermediate product 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol was obtained.

[0054] The 1H NMR spectrum of 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol is shown below. Figure 1 As shown;

[0055] A2: Preparation of imidazole-epoxy adduct microcapsule core: 5.0 g of the intermediate prepared in step 1 and 20.0 g of bisphenol A type epoxy resin (epoxy equivalent 190 g / eq, mass ratio 1:4) were added together into the reactor and heated to 105℃. High-speed shear stirring (2000 rpm) was started. After reacting for 45 minutes, the system was observed to gradually become turbid from a transparent liquid, and phase separation occurred. A large number of fine adduct solid particles were precipitated, indicating that the microcapsule core had been formed.

[0056] A3: In-situ silane surface grafting and shell construction: The reaction system was cooled to 70°C and kept in suspension with stirring. 1.0 g (4% of the total mass of the S2 system) of γ-glycidoxypropyltrimethoxysilane (KH-560) was slowly added dropwise to the system. The system was then kept at 70°C with stirring for 1.5 hours. The epoxy groups of the silane react with the residual active groups on the core surface. At the same time, the siloxane hydrolyzes and condenses to form a dense shell on the surface.

[0057] A4: Post-processing and powdering: After the reaction was completed, the mixture was quickly poured into a container cooled by an ice-water bath to terminate the reaction. After cooling to room temperature, 100 mL of xylene was added for dispersion and washing. The mixture was then filtered, and the filter cake was washed with xylene three times to completely remove unreacted liquid epoxy resin. The resulting solid product was vacuum dried at 50 °C for 12 hours, and then pulverized and classified by an air jet mill to obtain 21.5 g of silane-modified imidazole-epoxy adduct latent curing agent powder.

[0058] The infrared spectrum of the silane-modified imidazole-epoxy adduct latent curing agent is shown below. Figure 2 The silane shell is 1000-1100 cm. -1 A strong and broad absorption band appears at 1540-1640 cm⁻¹. -1 The C=N double bond stretching vibration of the imidazole ring exhibits a moderate-intensity spike at 3300-3500 cm⁻¹. -1 The region is characterized by a broad and blunt absorption valley where hydroxyl groups are visible, at a depth of 2900-3000 cm⁻¹. -1 The region has sharp small peaks, corresponding to CH bonds.

[0059] Examples 1-4, Comparative Examples 1-6

[0060] Preparation of a corrosion-resistant and weather-resistant insulating adhesive for the lead terminals of a power battery cell: Examples 1-4 and Comparative Examples 1-6 were prepared according to the following general preparation process, and their specific formulations (by mass parts) are shown in Table 1 below.

[0061] Table 1

[0062]

[0063] The modified epoxy resin is a mixture of hydrogenated bisphenol A and bisphenol F, with a mass ratio of 1:1.

[0064] The organosilicon toughening agent is a polyether-modified silicone oil;

[0065] The reactive diluent is butyl glycidyl ether;

[0066] The corrosion-resistant functional filler is a mixture of hydrophobically modified nano-silica and glass flakes, with a mass ratio of 1:1.

[0067] The coupling agent is γ-glycidoxypropyltrimethoxysilane;

[0068] The weather-resistant additive is a mixture of hindered amine light stabilizer (2,2,6,6-tetramethylpiperidine) and benzotriazole, with a mass ratio of 1:1.

[0069] Curing agent type I is the latent curing agent prepared using Preparation Example 1;

[0070] Curing agent type II is prepared according to the preparation method of preparation example 1, except that 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol is replaced with an equimolar amount of 2-ethyl-4-methylimidazolium;

[0071] Curing agent type III was prepared by referring to the preparation method of preparation example 1, and 2-ethyl-4-methylimidazol was directly blended with the resin (without microencapsulation treatment).

[0072] Curing agent type IV is a composition of dicyandiamide and 3-phenyl-1,1-dimethylurea (curing accelerator) in a mass ratio of 10:1;

[0073] Curing agent type V is 2-ethyl-4-methylimidazolium;

[0074] Curing agent type VI is a binuclear imidazole-epoxy adduct prepared by the preparation method of Preparation Example 1, but step A3 (silane surface grafting was not performed) was omitted.

[0075] Examples 1-4 and Comparative Examples 1-6 were all prepared using the following general process steps:

[0076] S1 packing pretreatment: The corrosion-resistant functional packing is dried in an oven at 110℃ for 3 hours. After taking it out, the speed is set to 500 rpm, and the coupling agent of the formula is added through a nozzle atomization. The mixture is stirred in a high-speed mixer at 1200 rpm for 2.5 hours, keeping the material temperature at 100℃. After cooling to room temperature, the modified corrosion-resistant functional packing is obtained.

[0077] S2 Resin Blending: Modified epoxy resin (hydrogenated bisphenol A type epoxy resin and bisphenol F type epoxy resin are mixed at a mass ratio of 1:1, wherein the epoxy value of hydrogenated bisphenol A type epoxy resin is 0.43-0.48 / eq / 100g) and reactive diluent are added to the reactor and stirred at a low speed of 50 rpm for 30 min at 50℃ until the mixture is uniform.

[0078] S3 Toughening and Dispersion: Add organosilicon toughening agent and weather-resistant agent to the S2 mixture, stir at 20 rpm for 10 minutes, and add modified corrosion-resistant functional filler in batches: First addition: Add 1 / 3 of the modified corrosion-resistant functional filler, stir at 30 rpm for 12 minutes; Second addition: Add 1 / 3 of the modified corrosion-resistant functional filler, stir at the same speed for 12 minutes; Third addition: Add the remaining 1 / 3 of the modified corrosion-resistant functional filler, stir at the same speed for 12 minutes. Turn on the high-speed dispersion disc (serrated impeller), set the speed to 2000 rpm, and at the same time, keep the planetary propeller rotating at 30 rpm to scrape the wall. Turn on the cooling water circulation, strictly control the material temperature to 60℃, and disperse for 45 minutes.

[0079] S4 Grinding and Degassing (Preparation of Component A): The mixed slurry obtained in S3 is ground by a three-roll mill. Temperature control: The roller temperature is strictly controlled at around 30℃ to prevent local overheating. Grind until the fineness detected by the scraper fineness gauge is less than 20μm. Then, degas it for 30 minutes under a vacuum of -0.095MPa to obtain a uniform component A.

[0080] S5 Mixing and Curing: When using, mix component A and component B (curing agent) evenly according to the proportions in Table 1, degas under vacuum, and apply and cure: Apply to the junction of the tab metal strip and perform a segmented curing procedure: pre-cur at 80℃ for 30 minutes, then heat to 135℃ and cure for 75 minutes.

[0081] Performance testing:

[0082] 1. Storage Stability Test: The mixed insulating adhesive (component A + component B) was sealed in a brown glass bottle and stored statically in a constant temperature and humidity chamber at 25℃±2℃ and 50%±5% relative humidity, avoiding light exposure. Samples were taken at 0 days and 360 days of storage. Following GB / T2794-2013, an NDJ-5S rotational viscometer was used with a No. 4 rotor at a speed of 60 rpm to read the stable values ​​at 25℃. The data are shown in Table 2.

[0083] 2. Shear bond strength test: The test was conducted in accordance with the test method of GB / T7124-2008, and the data are shown in Table 2.

[0084] 3. Power battery electrolyte immersion test: The electrolyte formula is 1 mol / L LiPF6-EC / DEC / DMC (volume ratio 1:1:1), simulating the commonly used electrolyte of power batteries. The cured sample is completely immersed in the electrolyte and placed in a 60℃ constant temperature oven for 300 hours. The shear bond strength is retested, and the data are shown in Table 2.

[0085] Table 2

[0086]

[0087] Table 2 data confirms the synergistic effect mechanism of the "core-shell structure" curing agent and the compound system. First, regarding storage stability, Examples 1-4 exhibited extremely low viscosity growth rates (only 10.4%-16.2%) and extremely high strength retention rates (>96%), thanks to the chemically inert design of the physically isolating shell constructed by silane modification and the dinuclear imidazole intermediate: the active hydrogen of imidazole was blocked by N-alkylation modification, and the silane shell physically blocked the initiator from the epoxy resin at room temperature, thus avoiding premature pre-curing reactions such as those in Comparative Example 4 (pure imidazole, direct gelation) and Comparative Example 5 (no shell adduct, viscosity surge of 278.9%). Second, regarding mechanical strength and corrosion resistance, the examples maintained extremely high shear strength (>21.6 MPa) after immersion in electrolyte for 300 hours, significantly better than Comparative Example 1 (mononuclear imidazole derivative) and Comparative Example 3 (traditional dicyandiamide system). This is because the dinuclear imidazole derivatives released after high-temperature desealing provide a higher density of cross-linking points, which, together with the organosilicon toughening agent, reduces internal stress. At the same time, the glass flake filler treated with coupling agent constructs a dense "maze effect" in the coating, which, together with the weather-resistant siloxane segments introduced by silane bonds, effectively blocks the penetration and erosion of electrolyte molecules, thus solving the defects of traditional amine-cured products that are prone to brittleness and have poor chemical resistance.

[0088] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A corrosion and weather resistant insulating glue for power battery cell lead terminals, characterized in that, This insulating adhesive is composed of component A and component B mixed in a mass ratio of 95-105:10-30; Component A, by weight, comprises the following raw materials: 40-60 parts modified epoxy resin; 10-25 parts organosilicon toughening modifier; 5-15 parts reactive diluent; 15-30 parts corrosion-resistant functional filler; 1-3 parts coupling agent; and 0.5-2 parts weather-resistant additive. Component B is a modified amine latent curing agent; The modified amine latent curing agent is a silane-modified imidazole-epoxy adduct latent curing agent; The corrosion-resistant functional filler is a composition formed by one or more combinations of flaky glass flakes and hydrophobically modified nano-silica or nano-alumina. The preparation method of the modified amine latent curing agent, which is a silane-modified imidazole-epoxy adduct latent curing agent, includes the following steps: A1. Synthesis of the binuclear imidazole intermediate: 2-Ethyl-4-methylimidazolium was dissolved in anhydrous ethanol or acetonitrile solvent, and an inorganic base was added as an acid-binding agent. 1,3-Dibromo-2-propanol was added dropwise under stirring, wherein the molar ratio of 2-ethyl-4-methylimidazolium to 1,3-dibromo-2-propanol was 2.0-2.2:

1. After the addition was complete, the temperature was raised to 75-85℃ and refluxed for 10-12 hours. After the reaction was completed, the solvent was recovered by vacuum distillation, and the generated inorganic salt was removed by washing with water. After filtration, drying and recrystallization, 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol was obtained. A2. Preparation of imidazole-epoxy adduct microcapsule core: 1,3-bis(2-ethyl-4-methylimidazol-1-yl)-2-propanol and bisphenol A type epoxy resin are mixed at a mass ratio of 1:3-5, heated to 90-110℃ and stirred at high speed until phase separation occurs in the reaction system and adduct solid particles precipitate out to form microcapsule core; A3. In-situ silane surface grafting and shell construction: Cool the reaction system to 60-75℃, add γ-glycidoxypropyltrimethoxysilane to the suspended A2 product, the amount added is 2%-6% of the total mass of the A2 system, and continue to keep warm and stir for 1-2 hours. A4. Post-treatment and powdering: After the reaction in A3 is completed, the mixture is rapidly cooled to room temperature to terminate the reaction. Non-polar solvent is added to wash away unreacted liquid epoxy resin. The solid product is separated by filtration and then vacuum dried at 50°C and classified by air jet milling to obtain a silane-modified imidazole-epoxy adduct latent curing agent with an average particle size of 3-10 μm. The nonpolar solvent is xylene or n-heptane; The modified epoxy resin is a mixture of hydrogenated bisphenol A type epoxy resin and bisphenol F type epoxy resin, with a mass ratio of 1:(0.5-1.5). The epoxy equivalent of the hydrogenated bisphenol A type epoxy resin is 180-220 g / eq.

2. The corrosion and weather resistant insulating glue for the lead terminal of the power battery cell according to claim 1, characterized in that, The organosilicon toughening modifier is any one of cyclodimethylsiloxane or polyether-modified silicone oil.

3. The corrosion and weather resistant insulating glue for the lead terminal of the power battery cell according to claim 1, characterized in that, The weather-resistant additive is a mixture of hindered amine light stabilizer and benzotriazole ultraviolet absorber in a mass ratio of 1:

1.

4. The corrosion and weather resistant insulating glue for the lead terminal of the power battery cell according to claim 1, characterized in that, The coupling agent is one of γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and vinyltriethoxysilane.

5. A method for preparing a corrosion-resistant and weather-resistant insulating glue for a lead terminal of a power battery cell according to any one of claims 1-4, characterized in that, The process includes the following steps: S1 packing pretreatment: The corrosion-resistant functional packing is dried at 100-120℃ for 2-4 hours, and the coupling agent is added and stirred for 2-3 hours to obtain the modified corrosion-resistant functional packing. S2 resin blending: The modified epoxy resin and reactive diluent are added to a reaction vessel and mixed evenly at 40-60℃; S3 Toughening and Dispersion: Add the organosilicon toughening modifier, modified corrosion-resistant functional filler and weather-resistant additive to the mixture in step S2, and perform high-speed shear dispersion at a speed of 1500-3000 rpm for 30-60 minutes. S4 Grinding and Degassing: The mixed slurry obtained in step S3 is ground to a fineness of less than 20 μm using a three-roll mill, and then degassed under vacuum at a pressure of -0.09 MPa to -0.1 MPa to obtain component A; S5 adhesive preparation: Mix component A and component B in the specified ratio before use, and apply after vacuum degassing.

6. The preparation method of the corrosion-resistant and weather-resistant power battery cell lead terminal insulation glue according to claim 5, characterized in that, In S3, when adding the modified corrosion-resistant functional filler, a step-by-step feeding method is adopted, adding 1 / 3 of the total amount each time, and stirring for 10-15 minutes after each addition.

7. The preparation method of the corrosion-resistant and weather-resistant power battery cell lead terminal insulation glue according to claim 5, characterized in that, In step S4, the roller temperature of the three-roll mill is controlled at 25-35℃ to prevent the material from pre-curing due to frictional heat.

8. The preparation method of the corrosion-resistant and weather-resistant power battery cell lead terminal insulation glue according to claim 5, characterized in that, The insulating adhesive is applied to the junction of the tab metal strip and the aluminum-plastic film or tab adhesive, and the curing conditions are: pre-curing at 80°C for 30 minutes, followed by post-curing at 120-150°C for 60-90 minutes.

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