High-temperature-resistant and damp-heat-aging-resistant two-component polyurethane structural adhesive for power battery and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant and damp-heat-aging-resistant two-component polyurethane structural adhesive for a power battery and a preparation method thereof, and belongs to the field of adhesive preparation. The structural adhesive comprises a component A and a component B which are combined for use according to the volume ratio of 1: 1, wherein the component A is prepared from bifunctional polyether polyol, trifunctional polyether polyol, aromatic ring modified polyol, polyol containing a cyclic structure, a micromolecular polyol chain extender, a coupling agent, a catalyst, a flame retardant, a water removal agent, an antioxidant and a thixotropic agent; and the component B is prepared from the following components: an isocyanate-terminated polyurethane prepolymer, a flame retardant, a thixotropic agent, a water removal agent and a hydrolysis-resistant agent. The structural adhesive has excellent bonding performance on various base materials, is high in strength and excellent in high temperature resistance and damp-heat aging resistance, can meet the performance requirements of a power battery PACK adhesive, effectively ensures that the performance of a power battery is stable when the power battery is used for a long time in complex environments such as high-frequency vibration, damp heat, severe cold, intense summer heat and heat accumulation, and improves the reliability and the safety.

Description

Technical Field

[0001] This invention relates to the field of adhesive preparation technology, and in particular to a two-component polyurethane structural adhesive for power batteries that is resistant to high temperature and damp heat aging, and its preparation method. Background Technology

[0003] Currently, the power batteries used in new energy vehicles are composed of multiple cells connected in series or parallel. With the innovation of power battery assembly processes, increasing energy density and the growing emphasis on modularization technologies, more and more metal structural components are being replaced by adhesives, leading to a continuous increase in adhesive usage. Furthermore, as the sales volume and installed capacity of power batteries continue to rise, adhesives have become one of the key factors in ensuring the stable, safe, efficient, and long-lasting operation of power battery-powered drive systems.

[0004] Two-component polyurethane adhesives have become the preferred choice due to their excellent elasticity and cushioning capabilities, superior electrical insulation, easily adjustable modulus, and high safety, environmental friendliness, and reliability. During vehicle operation, the structural bonding of two-component polyurethane adhesives must possess the ability to absorb and disperse high-frequency vibrations and impact energy, which is highly beneficial in reducing the risk of cell damage caused by mechanical stress. The strong polarity of urethane and isocyanate groups provides excellent bonding capabilities to materials such as Al, steel, PET, PC, and alloys. However, the reactive groups in the macromolecules can undergo hydrolysis and oxidation at high temperatures or with reactive molecules such as water, leading to decreased bond strength and poor resistance to aging and hydrolysis. This affects the excellent performance of polyurethane adhesives. Therefore, providing a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, extending its service life, and ensuring the safety and stability of the power battery during operation is a problem that needs to be solved.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a two-component polyurethane structural adhesive for power batteries that is resistant to high temperature and aging, and its preparation method. It has excellent adhesion to substrates such as aluminum, steel, PC, and PET, and has high strength, excellent resistance to high temperature and humid heat aging, and can meet the performance requirements of power battery PACK adhesives, thereby solving the problems of existing structural adhesives being not resistant to high temperature and having poor humid heat aging performance.

[0007] The objective of this invention is achieved through the following technical solution: A two-component polyurethane structural adhesive for power batteries, resistant to high temperature and damp heat aging, comprises: component A and component B used in a 1:1 volume ratio, with a functional group molar ratio of NCO:OH = 1.05:1 to 2.0:1; wherein, Component A is composed of the following raw materials in parts by mass: 10-40 parts of difunctional polyether polyol, 1-15 parts of trifunctional polyether polyol, 2-30 parts of aromatic ring modified polyol, 5-20 parts of polyol containing cyclic structure, 0.1-10 parts of small molecule polyol chain extender, 0.5-1.5 parts of coupling agent, 0.01-0.5 parts of catalyst, 10-40 parts of flame retardant, 2-10 parts of dehydrating agent, 0.1-0.5 parts of antioxidant and 0.5-5 parts of thixotropic agent; Component B is composed of the following raw materials in parts by mass: 60-85 parts of isocyanate-terminated polyurethane prepolymer, 10-40 parts of flame retardant, 0.5-5 parts of thixotropic agent, 0.1-0.5 parts of dehydrating agent, and 0.1-1 parts of anti-hydrolysis agent.

[0008] A method for preparing a two-component polyurethane structural adhesive for power batteries that is resistant to high temperature and damp heat aging, as described in this invention, includes the following steps: According to the formulation of component A and component B described in this invention, each component of component A and component B is taken and mixed evenly to obtain component A and component B. The obtained component A and component B are combined and used in a volume ratio of 1:1 to obtain a two-component polyurethane structural adhesive for power batteries that is resistant to high temperature and humid heat aging.

[0009] Compared with the prior art, the two-component polyurethane structural adhesive for power batteries with high temperature and aging resistance and its preparation method provided by the present invention have the following advantages: The addition of aromatic ring-modified polyols and cyclic polyols in component A increases the rigidity of the molecular chains, hinders chain movement, raises the glass transition temperature, and improves heat resistance. It also effectively enhances the adhesion strength to PET and metal substrates. The introduction of trifunctional polyols into component A increases the degree of crosslinking and improves heat resistance. The addition of difunctional polyether polyols in component A and dimer acid-based polyester polyols in component B improves the hydrophobicity of the molecular chains, enhances resistance to damp heat aging, increases chain flexibility, maintains high elongation, and promotes the formation of microphase separation structures after polyurethane curing, thus contributing to high mechanical properties. The addition of hydroxyl-terminated polyester polyols in component B increases the cohesive energy of the molecular chains, forms a barrier against water molecules, restricts molecular movement, slows down the hydrolysis reaction rate, and simultaneously improves heat resistance and aging resistance. The polyurethane structural adhesive of the present invention has the following characteristics: (1) High strength, with a tensile strength ≥15MPa and a shear strength ≥12MPa for substrates such as PET, PC, aluminum alloy, and steel, ensuring safety and reliability during operation. (2) Excellent resistance to damp heat aging; after aging with double 85 for 1000h, the tensile strength and shear strength decrease by <10%. (3) Good high temperature resistance; at 80℃, the shear strength is ≥3MPa and the tensile strength is ≥5MPa. Detailed Implementation

[0010] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, which do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0011] First, the following explanations are provided for the terms that may be used in this article: The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0012] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0013] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0014] The term "parts by mass" indicates the mass ratio between multiple components. For example, if component X is described as x parts by mass and component Y as y parts by mass, then the mass ratio of component X to component Y is x:y. One part by mass can represent any mass; for example, one part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts; it can be greater than 100 parts, less than 100 parts, or equal to 100 parts. Unless otherwise stated, parts, proportions, and percentages mentioned herein are all measured by mass.

[0015] When concentration, temperature, pressure, size, or other parameters are expressed as numerical ranges, such ranges should be understood to specifically disclose all ranges formed by any pairing of upper limits, lower limits, or preferred values ​​within that range, regardless of whether the range is explicitly stated; for example, if the numerical range "2 to 8" is stated, then that range should be interpreted to include ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise stated, the numerical ranges described herein include both their endpoints and all integers and fractions within that range.

[0016] The solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0017] This invention provides a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, comprising: component A and component B used in a 1:1 volume ratio, with a functional group molar ratio of NCO:OH = 1.05:1 to 2.0:1; wherein, Component A is composed of the following raw materials in parts by mass: 10-40 parts of difunctional polyether polyol, 1-15 parts of trifunctional polyether polyol, 2-30 parts of aromatic ring modified polyol, 5-20 parts of polyol containing cyclic structure, 0.1-10 parts of small molecule polyol chain extender, 0.5-1.5 parts of coupling agent, 0.01-0.5 parts of catalyst, 10-40 parts of flame retardant, 2-10 parts of dehydrating agent, 0.1-0.5 parts of antioxidant and 0.5-5 parts of thixotropic agent; Component B is composed of the following raw materials in parts by mass: 60-85 parts of isocyanate-terminated polyurethane prepolymer, 10-40 parts of flame retardant, 0.5-5 parts of thixotropic agent, 0.1-0.5 parts of dehydrating agent, and 0.1-1 parts of anti-hydrolysis agent.

[0018] Preferably, in component A of the above-mentioned polyurethane structural adhesive, the difunctional polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polybutanediol, and the hydroxyl value of the difunctional polyether polyol is 20 mg KOH / g to 300 mg KOH / g. The hydroxyl value of the trifunctional polyether polyol is 50 mg KOH / g to 450 mg KOH / g; The aromatic ring modified polyol is one or more of bisphenol A or bisphenol F modified polyether diols and phthalic anhydride polyester diols with a molecular weight of 400 to 3000.

[0019] Preferably, in component A of the above-mentioned polyurethane structural adhesive, the polyol containing a cyclic structure is one or more of polyether polyol containing an aromatic ring structure and dicyclopentadiene type polyol, and the hydroxyl value of the polyether polyol containing an aromatic ring structure is 150mg KOH / g to 450mg KOH / g. The small molecule polyol chain extender is one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, dipropylene glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentanediol, glycerol, and pentaerythritol. The coupling agent is one or more of the following silane coupling agents: KH550, KH560, KH570, KH580, and KH792. The catalyst is one or more of N,N-dimethylcyclohexylamine, triethylenediamine, 1,2-dimethylimidazolium, N-ethylmorpholine, N-methylmorpholine, bismuth isooctanoate, bismuth laurylate, bismuth neodecanoate, bismuth naphthenate, zinc isooctanoate, zinc neodecanoate, dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, and chelated tin. The antioxidant is one or more of 1076, 1010, 1135 and 245; The dehydrating agent is one or more of molecular sieves, calcium chloride, and aluminum sulfate.

[0020] Preferably, in components A and B of the above-mentioned polyurethane structural adhesive, the flame retardant is a solid flame retardant or a liquid flame retardant; wherein, the solid flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, and aluminum diethylphosphite; and the liquid flame retardant is one or more of tricresyl phosphate, triethyl phosphate, and tri(chloroisopropyl) phosphate.

[0021] Preferably, in the above-mentioned polyurethane structural adhesive, the thixotropic agent in components A and B is one or more of fumed silica and bentonite.

[0022] Preferably, in component B of the above-mentioned polyurethane structural adhesive, the isocyanate-terminated polyurethane prepolymer is a prepolymer prepared from isocyanate and polyol, and the mass fraction of NCO is controlled to be 5-20%. The anti-hydrolysis agent is polycarbodiimide; The dehydrating agent is p-toluenesulfonyl isocyanate.

[0023] Preferably, in the above-mentioned polyurethane structural adhesive, in the isocyanate-terminated polyurethane prepolymer, the polyol is a polyether polyol and a polyester polyol, wherein the polyether polyol is one or more of polyethylene glycol, polypropylene glycol, and polybutanediol; the polyester polyol is a polyester polyol synthesized from diacid or anhydride monomers and polyol monomers, and the molar ratio of hydroxyl to carboxyl groups of the polyester polyol is 1.2 to 1.5; The isocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate, and liquefied MDI.

[0024] Preferably, in the above-mentioned polyurethane structural adhesive, the diacid or anhydride monomer is one or more of hydrogenated dimer acid, dimer acid, succinic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, and phthalic anhydride. The polyol monomer is one or more of the following: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 1,10-decanediol, diethylene glycol, glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0025] The present invention also provides a method for preparing the above-mentioned high-temperature and humid heat aging resistant two-component polyurethane structural adhesive for power batteries, characterized by comprising the following steps: According to the above formulations for components A and B, take the raw materials of components A and B respectively, mix them evenly to obtain components A and B, and use the obtained components A and B in a volume ratio of 1:1 to obtain a two-component polyurethane structural adhesive for power batteries that is resistant to high temperature and humid heat aging.

[0026] Preferably, in the above method, if the polyol in the isocyanate-terminated prepolymer of component B is a polyester polyol, the polyester polyol is prepared in the following manner, including: Diosmic acid or anhydride monomers and polyol monomers are fed in a ratio of 1.2 to 1.5 molar ratios of hydroxyl and carboxyl groups. Tetrabutyl titanate and triphenyl phosphite are added simultaneously. Under the protection of an inert gas, the temperature is gradually increased from 180°C to 240°C for esterification for 6 hours. After the esterification reaction is completed, the vacuum degree is maintained at 3 kPa and the pre-condensation is carried out at 240°C for 2 hours. Then, the vacuum degree is increased to below 300 Pa and the polycondensation is carried out at 240°C for 2 hours. After reaching the endpoint, the vacuum is broken with nitrogen, and the hydroxyl value is titrated. If the error is less than 5% compared with the theoretical value, the polyester polyol is obtained. The isocyanate-terminated prepolymer is prepared in the following manner, including: The polyester polyol obtained above is heated to 110-120°C, stirred and vacuumed, and dehydrated for 1-3 hours. Then, it is cooled to below 50°C, nitrogen is introduced, and isocyanate is added according to the theoretical NCO content of 5-20%. The temperature is raised to 65-85°C, and the reaction is stirred continuously for 1-5 hours until the NCO content no longer changes when titrated. The reaction is then stopped and cooled to room temperature to obtain the terminal isocyanate prepolymer.

[0027] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of the solution provided by the embodiments of the present invention is provided with reference to specific examples.

[0028] Example 1 This embodiment provides a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, and its preparation method includes: Polyester polyol is prepared in advance, and then isocyanate-terminated prepolymer is prepared, wherein the isocyanate-terminated prepolymer and each raw material are in parts by mass. (1) To prepare polyester polyol, take 24 parts of 1,6-hexanediol and 76 parts of dimer acid, add 200 ppm of tetrabutyl titanate and triphenyl phosphite to the total system, and gradually increase the temperature from 180℃ to 240℃ under nitrogen protection for 6 hours of esterification. After the esterification reaction is completed, maintain a vacuum of 3 kPa and pre-condense at 240℃ for 2 hours. Then increase the vacuum to below 300 Pa and polycondense at 240℃ for 2 hours. Use nitrogen to break the vacuum, take a sample and titrate the hydroxyl value. If the error is less than 5% compared with the theoretical error, the polyester polyol is obtained.

[0029] (2) To prepare the terminal isocyanate prepolymer, take 45 parts of polydimeric hexanediol with a molecular weight of 2000-3000, stir and heat to 120°C, keep vacuum to remove water for 2 hours, cool down to 40°C, fill with nitrogen, add 55 parts of liquefied MDI, slowly heat to 80°C, stir and react for 2 hours, cool to room temperature to obtain the terminal isocyanate prepolymer.

[0030] Component A and component B are then prepared separately, wherein each raw material in component A and component B is expressed in parts by mass. (3) Preparation of component A: Take 30 parts PTMG-1000, 5 parts Mn400, 10 parts bisphenol A modified polyol, 10 parts aromatic polyether polyol, 2 parts triethylene glycol, 1.0 part KH560, 0.2 parts dibutyltin dilaurate, 30 parts aluminum hydroxide, 5 parts molecular sieve, 1.5 parts fumed silica, and 0.5 parts 1010, disperse and stir evenly, and obtain component A after stirring for 2 hours; (4) Preparation of component B: Take 70 parts of the prepolymer with terminal isocyanate group prepared above, 30 parts of aluminum hydroxide, 0.5 parts of p-toluenesulfonyl isocyanate, 1.5 parts of fumed silica, and 0.5 parts of polycarbodiimide, and stir for 2 hours to obtain component B.

[0031] Example 2 This embodiment provides a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, and its preparation method includes: A pre-prepared terminal polyester polyol was prepared, followed by the preparation of a terminal isocyanate-based prepolymer, wherein the terminal isocyanate-based prepolymer and each raw material were prepared in parts by mass. (1) To prepare polyester polyol, take 24 parts of 1,6-hexanediol and 76 parts of hydrogenated dimer acid, add 200 ppm of tetrabutyl titanate and triphenyl phosphite to the total system, and gradually increase the temperature from 180℃ to 240℃ under nitrogen protection for 6 hours of esterification. After the esterification reaction is completed, maintain a vacuum of 3 kPa and pre-condense at 240℃ for 2 hours. Then increase the vacuum to below 300 Pa and condense at 240℃ for 2 hours. Use nitrogen to break the vacuum, take a sample and titrate the hydroxyl value. If the error is less than 5% compared with the theoretical error, the polyester polyol is obtained.

[0032] (2) To prepare the terminal isocyanate prepolymer, take 58 parts of polyhydrogenated dimer glycol ester with a molecular weight of 2000-3000, stir and heat to 120°C, keep vacuum to remove water for 2 hours, cool down to 40°C, fill with nitrogen, add 42 parts of NDI, slowly heat to 80°C, stir and react for 4 hours, cool to room temperature to obtain the terminal isocyanate prepolymer.

[0033] Component A and component B are then prepared separately, wherein each raw material in component A and component B is expressed in parts by mass. (3) Preparation of component A: Take 30 parts PTMG-2000, 10 parts Mn400, 5 parts bisphenol A modified polyol, 10 parts aromatic polyether polyol, 2 parts triethylene glycol, 1.0 part KH560, 0.2 parts dibutyltin dilaurate, 30 parts aluminum hydroxide, 5 parts molecular sieve, 1.5 parts fumed silica, and 0.5 parts 1135, disperse and stir evenly, and obtain component A after stirring for 2 hours; (4) Preparation of component B: Take 70 parts of the prepolymer with terminal isocyanate group, 30 parts of aluminum hydroxide, 0.5 parts of p-toluenesulfonyl isocyanate, 1.5 parts of fumed silica, and 0.5 parts of polycarbodiimide obtained above, and stir for 2 hours to obtain component B.

[0034] Example 3 This embodiment provides a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, and its preparation method includes: A pre-prepared terminal polyester polyol was prepared, followed by the preparation of a terminal isocyanate-based prepolymer, wherein the terminal isocyanate-based prepolymer and each raw material were prepared in parts by mass. (1) To prepare polyester polyol, take 14 parts of 1,6-hexanediol, 54 parts of dimer acid, 13 parts of neopentyl glycol, 19 parts of sebacic acid, add 200 ppm of tetrabutyl titanate and triphenyl phosphite to the total system, and under the protection of nitrogen, gradually increase the temperature from 180℃ to 240℃ and esterify for 6 hours. After the esterification reaction is completed, maintain a vacuum of 3 kPa and pre-condense at 240℃ for 2 hours. Then increase the vacuum to below 300 Pa and polycondense at 240℃ for 2 hours. Use nitrogen to break the vacuum, take a sample and titrate the hydroxyl value. If the error is less than 5% compared with the theoretical error, the polyester polyol is obtained.

[0035] (2) To prepare isocyanate-terminated polyurethane prepolymer, take 65 parts of poly(dimeric hexanediol-polydecanoic acid neopentyl glycol) ester with a molecular weight of 2000-3000, stir and heat to 120°C, keep vacuum to remove water for 2 hours, cool down to 40°C, purge with nitrogen, add 35 parts of TDI, slowly heat to 85°C, stir and react for 5 hours, cool to room temperature to obtain isocyanate-terminated prepolymer.

[0036] Component A and component B are then prepared separately, wherein each raw material in component A and component B is expressed in parts by mass. (3) Preparation of component A: Take 35 parts PPG-1000, 6 parts Mn700, 5 parts bisphenol F modified polyol, 10 parts aromatic polyether polyol, 1.0 part KH560, 0.1 part 1,2-dimethylimidazole, 30 parts aluminum hypophosphite, 5 parts molecular sieve, 1.5 parts fumed silica, and 0.5 parts 1076, disperse and stir evenly, and obtain component A after stirring for 3 hours; (4) Preparation of component B: Take 60 parts of the prepolymer with terminal isocyanate group, 40 parts of aluminum hypophosphite, 0.5 parts of p-toluenesulfonyl isocyanate, 1.5 parts of fumed silica, and 0.5 parts of polycarbodiimide obtained above, and stir for 3 hours to obtain component B.

[0037] Example 4 This embodiment provides a two-component polyurethane structural adhesive for power batteries that is resistant to high temperatures and damp heat aging, and its preparation method includes: A pre-prepared terminal polyester polyol was prepared, followed by the preparation of a terminal isocyanate-based prepolymer, wherein the terminal isocyanate-based prepolymer and each raw material were prepared in parts by mass. (1) To prepare polyester polyol, take 15 parts of 1,6-hexanediol, 57 parts of dimer acid, 13 parts of diethylene glycol, 15 parts of phthalic anhydride, add 200 ppm of tetrabutyl titanate and triphenyl phosphite to the total system, and under the protection of nitrogen, gradually increase the temperature from 180℃ to 240℃ and esterify for 6 hours. After the esterification reaction is completed, maintain the vacuum degree of 3KPa and pre-condense at 240℃ for 2 hours. Then increase the vacuum degree to below 300Pa and condense at 240℃ for 2 hours. Use nitrogen to break the vacuum, take a sample and titrate the hydroxyl value. If the error is less than 5% compared with the theoretical error, the polyester polyol is obtained.

[0038] (1) To prepare the terminal isocyanate prepolymer, take 58 parts of poly(diethylene glycol dimer acid-poly(diethylene glycol phthalate)) with a molecular weight of 2000-3000, stir and heat to 120°C, keep vacuum to remove water for 2 hours, cool down to 40°C, purge with nitrogen, add 42 parts of NDI, slowly heat up to 80°C, stir and react for 4 hours, cool to room temperature to obtain the terminal isocyanate prepolymer.

[0039] Component A and component B are then prepared separately, wherein each raw material in component A and component B is expressed in parts by mass. (2) Preparation of component A: Take 35 parts of DCPD-1000, 6 parts of Mn700, 5 parts of bisphenol F modified polyol, 10 parts of aromatic polyether polyol, 1.0 part of KH560, 0.1 part of bismuth neodecanoate, 30 parts of aluminum hypophosphite, 5 parts of molecular sieve, 1.5 parts of fumed silica, and 0.5 parts of 1010. Disperse and stir evenly. After stirring for 3 hours, component A is obtained. (3) Preparation of component B: Take 70 parts of the prepolymer with terminal isocyanate group, 30 parts of aluminum hypophosphite, 0.5 parts of p-toluenesulfonyl isocyanate, 1.5 parts of fumed silica, and 0.5 parts of polycarbodiimide obtained above, and stir for 3 hours to obtain component B. The two-component polyurethane structural adhesive for power batteries prepared in the above embodiments, which is resistant to high temperature and damp heat aging, is used with component A and component B in a volume ratio of 1:1. The tensile strength and shear strength at 25°C, at 80°C, and after aging at double 85 for 1000 hours are tested. The substrates are untreated aluminum alloy and PET. The test data are shown in Table 1 below.

[0040] Table 1 shows the performance test data of the polyurethane structural adhesives in each embodiment. .

[0041] As can be seen from the test data in Table 1 above, the two-component polyurethane structural adhesive for power batteries of the present invention, which is resistant to high temperature and damp heat aging, has excellent high temperature resistance, with a shear strength ≥3MPa at 80℃ and a bulk tensile strength ≥5MPa. At the same time, it has excellent shear strength for untreated Al and PET at room temperature. After 1000 hours of aging at double 85, the attenuation is less than 10%. It can effectively ensure the performance stability of power batteries during long-term use in complex environments such as high-frequency vibration, damp heat, severe cold, extreme heat, and heat accumulation, as well as their stability during transportation and storage, thereby improving reliability and safety.

[0042] The structural adhesive of this invention has excellent adhesion to substrates such as aluminum, steel, PC, and PET, and has high strength, excellent resistance to high temperature and humid heat aging. It can meet the performance requirements of power battery PACK adhesives, effectively ensuring the stable performance of power batteries under complex environments such as high-frequency vibration, humid heat, severe cold, extreme heat, and heat accumulation, thereby improving reliability and safety.

[0043] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A high-temperature and moisture-heat aging resistant two-component polyurethane structural adhesive for power batteries, characterized in that, Comprising: A component and a B component used in combination at a volume ratio of 1:1, a functional group molar ratio of: NCO:OH = 1.05:1~2.0:1; wherein, The A component is composed of the following raw materials in mass fraction: difunctional polyether polyol 10~40 parts, trifunctional polyether polyol 1~15 parts, aromatic ring modified polyol 2~30 parts, cyclic structure containing polyol 5~20 parts, small molecule polyol chain extender 0.1~10 parts, coupling agent 0.5~1.5 parts, catalyst 0.01~0.5 parts, flame retardant 10~40 parts, water removal agent 2~10 parts, antioxidant 0.1~0.5 parts and thixotropic agent 0.5~5 parts; The B component is composed of the following raw materials in mass fraction: isocyanate-terminated polyurethane prepolymer 60~85 parts, flame retardant 10~40 parts, thixotropic agent 0.5~5 parts, water removal agent 0.1~0.5 parts and hydrolysis inhibitor 0.1~1 parts. 2.The high-temperature and damp-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 1, characterized in that, In the A component, the difunctional polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polybutylene glycol, and the hydroxyl value of the difunctional polyether polyol is 20mg KOH / g~300mg KOH / g; The hydroxyl value of the trifunctional polyether polyol is 50mg KOH / g~450mg KOH / g; The aromatic ring modified polyol is one or more of bisphenol A or bisphenol F modified polyether diol with a molecular weight of 400~3000, and phthalic anhydride polyester diol. 3.The high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 1, characterized in that, In the A component, the cyclic structure containing polyol is one or more of aromatic ring structure containing polyether polyol and dicyclopentadiene type polyol, and the hydroxyl value of the aromatic ring structure containing polyether polyol is 150mg KOH / g~450mg KOH / g; The small molecule polyol chain extender is one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, dipropylene glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, glycerol and pentaerythritol; The coupling agent is one or more of silane coupling agents KH550, KH560, KH570, KH580 and KH792; The catalyst is one or more of N,N-dimethylcyclohexylamine, triethylenediamine, 1,2-dimethylimidazole, N-ethylmorpholine, N-methylmorpholine, bismuth isooctoate, bismuth laurate, bismuth neodecanoate, bismuth naphthenate, zinc isooctoate, zinc neodecanoate, dibutyl tin dilaurate, dibutyl tin diacetate, stannous octoate and chelated tin; The antioxidant is one or more of 1076, 1010, 1135 and 245; The water removal agent is one or more of molecular sieves, calcium chloride and aluminum sulfate. 4.The high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 1, characterized in that, In the A component and the B component, the flame retardant is a solid flame retardant or a liquid flame retardant; The thixotropic agent is one or more of fumed silica and bentonite. 5.The high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 4, characterized in that, The solid flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite and aluminum diethyl hypophosphite; The liquid flame retardant is one or more of tricresyl phosphate, triethyl phosphate, tris(chloroisopropyl) phosphate. 6.The high-temperature and damp-heat aging resistant two-component polyurethane structural adhesive for power batteries according to any one of claims 1-5, characterized in that, In the B component, the terminal isocyanate group polyurethane prepolymer is a prepolymer prepared from isocyanate and polyol, and the mass fraction of NCO is controlled to be 5-20%; The anti-hydrolysis agent is polycarbodiimide; The water removal agent is p-toluenesulfonyl isocyanate. 7.The high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 6, characterized in that, In the terminal isocyanate group polyurethane prepolymer, the polyol is polyether polyol and polyester polyol, wherein the polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polybutylene glycol; the polyester polyol is a polyester polyol synthesized from diacid monomer and polyol monomer, and the molar ratio of hydroxyl group to carboxyl group of the polyester polyol is 1.2-1.5; The isocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate and liquefied MDI. 8.The high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 7, characterized in that, The diacid monomer is one or more of hydrogenated dimer acid, dimer acid, succinic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid and phthalic anhydride; The polyol monomer is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, diethylene glycol, glycerol, trimethylol ethane, trimethylol propane and pentaerythritol.

9. A method for preparing the high-temperature-resistant and hydrothermal-aging-resistant two-component polyurethane structural adhesive for power batteries according to any one of claims 1-8, characterized in that, The method comprises the following steps: The A component and the B component are prepared by mixing the raw materials of the A component and the B component respectively according to any one of claims 1-8, and the A component and the B component are mixed uniformly, and then the A component and the B component prepared are combined in a volume ratio of 1:1 to obtain the two-component polyurethane structural adhesive for high-temperature and damp-heat aging-resistant power batteries.

10. The preparation method of the high-temperature and wet-heat aging resistant two-component polyurethane structural adhesive for power batteries according to claim 9, characterized in that, If the polyol in the terminal isocyanate group prepolymer in the B component is a polyester polyol, the polyester polyol is prepared in the following manner, which comprises: The diacid or anhydride monomer and the polyol monomer are fed in a molar ratio of hydroxyl group to carboxyl group of 1.2-1.5, and tetrabutyl titanate and triphenyl phosphite are added at the same time, and then the temperature is gradually increased from 180°C to 240°C under the protection of inert gas, and esterification is performed for 6 hours; after the esterification reaction is completed, the vacuum degree is maintained at 3 KPa, and pre-condensation is performed at 240°C for 2 hours; then the vacuum degree is increased to below 300 Pa, and polycondensation is performed at 240°C for 2 hours; after the end point is reached, the vacuum is broken by using nitrogen, and the hydroxyl value of the sample is titrated; compared with the theoretical error, the error is less than 5%, and thus the polyester polyol is obtained; The terminal isocyanate group prepolymer is prepared in the following manner, which comprises: The polyester polyol prepared above is heated to 110-120°C, and then dehydrated for 1-3 hours under vacuum stirring; then the temperature is decreased to below 50°C, nitrogen is filled, and isocyanate is added in a ratio of 5-20% of the theoretical NCO content; the temperature is increased to 65-85°C, and then stirring reaction is continuously performed for 1-5 hours until the NCO content no longer changes, and then the reaction is completed; and then the temperature is cooled to room temperature, and thus the terminal isocyanate group prepolymer is obtained.