Polyurethane foam pouring sealant for battery unit and preparation method of polyurethane foam pouring sealant

Abstract

The invention provides a polyurethane foam pouring sealant for a battery unit and a preparation method of the polyurethane foam pouring sealant, and belongs to the technical field of pouring sealants. The polyurethane foam pouring sealant for the battery unit comprises a component A and a component B, the component A comprises first polyether polyol, second polyether polyol, vegetable oil modified polyol, a foam stabilizer, a heat-conducting filler, a foaming agent and a flame retardant; wherein the first polyether polyol takes polyamine as an initiator, the second polyether polyol takes second polyol as an initiator, the functionality of the second polyol is 4-6, the third polyether polyol takes third polyol as an initiator, and the functionality of the third polyol is 3; and the component B comprises isocyanate, third polyether polyol and an amino silane coupling agent. According to the invention, a plurality of different polyether polyols are used as raw materials, and the components are combined and interact with one another, so that the polyurethane foam pouring sealant with low viscosity, good fluidity, high thermal conductivity, high strength and high flexibility is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of potting adhesives, and particularly relates to a polyurethane foam potting adhesive for battery cells and a preparation method thereof. Background Art

[0002] To ensure the stability, heat conduction, shock absorption, flame retardancy, and safety of the battery cells inside a whole pack of power batteries, potting treatment must be carried out on the whole pack of batteries. Polyurethane and silicone rubber meet the above performance requirements with their excellent properties. However, the densities of the polyurethane and silicone potting adhesives currently used on the market are both greater than 1.05 g / cm 3 Above, and some even add a large amount of thermal conductive fillers to the potting adhesive system in order to increase the thermal conductivity, resulting in a significant increase in the weight of the battery pack, affecting the weight of the new energy vehicle body and increasing the battery energy consumption. With the national lightweight requirement and the reduction of the vehicle body self-weight, the weight requirement for the adhesive will inevitably become higher and higher. Polyurethane foam potting adhesive has a low density and excellent comprehensive performance, and is bound to meet the needs of new energy batteries. Patent 202111075273.9 prepared a polyurethane foam potting adhesive for the field of power batteries, and this patent does not involve the thermal conductivity. Patents such as 202180095371.0 and 202411281925.8 provide a polyurethane foam potting adhesive, and the volume thermal conductivity of the polyurethane foam potting adhesive is <0.05 W / (M·K), which cannot achieve a good heat dissipation effect and cannot meet the requirements of power batteries for thermal management. Power battery thermal management is a very important part of electric vehicle engineering. 202311011127.9 provides a highly thermally conductive silicone block polyurethane foaming potting adhesive, which does not involve the viscosity of the potting adhesive, and this potting adhesive cannot fully level the fine gaps inside the power battery, resulting in a poor potting effect.

[0003] In view of this, it is urgent to determine a low-viscosity polyurethane foam thermally conductive potting adhesive at present, so that it has the effects of low viscosity, easy potting, stabilizing the battery cells, low density, high thermal conductivity, and high flame retardancy. Summary of the Invention

[0004] The purpose of the present disclosure is to overcome the deficiencies of the prior art and provide a polyurethane foam potting adhesive for battery cells and a preparation method thereof.

[0005] To achieve the above purpose, the technical solutions adopted by the present disclosure are as follows:

[0006] On the one hand, a polyurethane foam potting adhesive for battery cells is provided, which includes component A and component B;

[0007] The A component comprises the following components in parts by weight: The A component comprises the following components in parts by weight: 10-30 parts of a first polyether polyol, 20-40 parts of a second polyether polyol, 10-30 parts of a vegetable oil-modified polyol, 2-10 parts of a foam stabilizer, 80-120 parts of a heat-conducting filler, 0.1-1 part of a foaming agent, and 30-60 parts of a flame retardant;

[0008] The B component comprises the following components in parts by weight: 50-70 parts of an isocyanate, 20-40 parts of a third polyether polyol, and 1-5 parts of an amino-silane coupling agent;

[0009] The first polyether polyol uses a polyamine as an initiator;

[0010] The second polyether polyol uses a second polyol as an initiator, and the functionality of the second polyol is 4-6;

[0011] The third polyether polyol uses a third polyol as an initiator, and the functionality of the third polyol is 3.

[0012] On the other hand, a preparation method of the polyurethane foam potting adhesive for the battery cell is provided, comprising the following steps:

[0013] Preparing the A component: After uniformly mixing the first polyether polyol, the second polyether polyol, the vegetable oil-modified polyol, the flame retardant, and the heat-conducting filler, adding the foam stabilizer and the foaming agent, and stirring evenly to obtain the A component;

[0014] Preparing the B component: Adding the third polyether polyol into a reaction kettle, evacuating for 1-2 h at a temperature of 100-110 °C, cooling to 65-75 °C, introducing nitrogen, adding the isocyanate, then reacting at a temperature of 55-65 °C for 3-5 h, then cooling to room temperature, and adding the amino-silane coupling agent to react for 1-2 h to obtain the B component;

[0015] Preparing the polyurethane foam potting adhesive for the battery cell: During use, uniformly mixing the A component and the B component in proportion to obtain the polyurethane foam potting adhesive for the battery cell.

[0016] Compared with the prior art, the beneficial effects of the present disclosure are as follows: The present invention uses a variety of different polyether polyols as raw materials, combines each component, and interacts with each other to obtain a polyurethane foam potting adhesive with low viscosity, good fluidity, high thermal conductivity, high strength and high flexibility. The first polyether polyol with polyamine as the initiator acts as a catalyst to achieve slow initiation, enabling the polyurethane foam potting adhesive to have sufficient time to level, thereby achieving a good potting effect. In addition, on the one hand, heat-conducting fillers are added to make the polyurethane foam potting adhesive have good heat-conducting effect. On the other hand, flame retardants are added to improve the flame retardancy of the polyurethane foam potting adhesive. At the same time, the flame retardants interact with other components to reduce the viscosity of the polyurethane foam potting adhesive and improve its fluidity, making it easy to achieve potting and coating. In component B, through the reaction of the third polyether polyol and isocyanate, the flexibility of the polyurethane foam potting adhesive is improved. On this basis, an amino-silane coupling agent is added to improve the tensile strength, hardness and adhesion of the polyurethane foam potting adhesive. Detailed Embodiments

[0017] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosed content of the present disclosure more thorough and comprehensive.

[0018] As used herein, the terms:

[0019] "Prepared from..." is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or device.

[0020] The connecting phrase "consisting of..." excludes any unstated element, step or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of..." appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0021] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed individually. For example, when the range "1 - 5" is disclosed, the described range should be interpreted to include ranges such as "1 - 4", "1 - 3", "1 - 2", "1 - 2 and 4 - 5", "1 - 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0022] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0023] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass of component A is a parts by mass and the mass of component B is b parts by mass, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0024] "And / or" is used to indicate that either one or both of the described situations may occur. For example, A and / or B includes (A and B) and (A or B).

[0025] In a first aspect of the present invention, there is provided a polyurethane foam potting adhesive for battery cells, comprising component A and component B;

[0026] Component A comprises the following components in parts by weight: Component A comprises the following components in parts by weight: the first polyether polyol 10 - 30 parts, the second polyether polyol 20 - 40 parts, the vegetable oil-modified polyol 10 - 30 parts, the foam stabilizer 2 - 10 parts, the thermal conductive filler 80 - 120 parts, the blowing agent 0.1 - 1 part, the flame retardant 30 - 60 parts;

[0027] Component B comprises the following components in parts by weight: isocyanate 50 - 70 parts, the third polyether polyol 20 - 40 parts, the amino silane coupling agent 1 - 5 parts;

[0028] The first polyether polyol uses polyamine as the initiator;

[0029] The second polyether polyol uses the second polyol as the initiator, and the functionality of the second polyol is 4 - 6;

[0030] The third polyether polyol uses a third polyol as the initiator, and the functionality of the third polyol is 3.

[0031] The present invention uses a variety of different polyether polyols as raw materials, combines each component, and interacts with each other to obtain a polyurethane foam potting adhesive with low viscosity, good fluidity, high thermal conductivity, high strength and high flexibility. The first polyether polyol with polyamine as the initiator acts as a catalyst to achieve slow initiation, enabling the polyurethane foam potting adhesive to have enough time to level, thus achieving a good potting effect; in addition, on the one hand, a thermal conductive filler is added to make the polyurethane foam potting adhesive have good thermal conductivity, and on the other hand, a flame retardant is added to improve the flame retardancy of the polyurethane foam potting adhesive. At the same time, the flame retardant interacts with other components to reduce the viscosity of the polyurethane foam potting adhesive and improve the fluidity of the polyurethane foam potting adhesive, making it easy to achieve potting and coating; in component B, through the reaction of the third polyether polyol and isocyanate, the flexibility of the polyurethane foam potting adhesive is improved. On this basis, an amino silane coupling agent is added to improve the tensile strength, hardness and adhesion of the polyurethane foam potting adhesive.

[0032] In different embodiments, the weight parts of the first polyether polyol can be, but are not limited to, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts;

[0033] In different embodiments, the weight parts of the second polyether polyol can be, but are not limited to, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts;

[0034] In different embodiments, the weight parts of the vegetable oil-modified polyol can be, but are not limited to, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts;

[0035] In different embodiments, the weight parts of the foam stabilizer can be, but are not limited to, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts;

[0036] In different embodiments, the weight parts of the thermal conductive filler can be, but are not limited to, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts;

[0037] In different embodiments, the weight parts of the blowing agent can be, but are not limited to, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part;

[0038] In different embodiments, the weight parts of the flame retardant can be, but are not limited to, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts;

[0039] In different embodiments, the weight parts of the isocyanate can be, but are not limited to, 50 parts, 52 parts, 55 parts, 57 parts, 60 parts, 63 parts, 65 parts, 68 parts, 70 parts;

[0040] In different embodiments, the weight parts of the third polyether polyol can be, but are not limited to, 20 parts, 22 parts, 25 parts, 27 parts, 30 parts, 33 parts, 35 parts, 38 parts, 40 parts;

[0041] In different embodiments, the weight parts of the aminosilane coupling agent can be, but are not limited to, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts.

[0042] In some embodiments, the mass ratio of component A to component B is 1:1.

[0043] In some embodiments, the mass of the first polyether polyol is 5-15% of the total mass of component A, and can be, for example, but not limited to, 5%, 7%, 9%, 11%, 13%, 15%; preferably 7-13%. Based on the mass of component A being 100%, when the mass percentage of the first polyether polyol is 5-15%, the overall performance of the obtained polyurethane foam potting adhesive is better.

[0044] In some embodiments, the hydroxyl value of the third polyether polyol is 30-80 mgKOH / g, and can be, for example, but not limited to, 30 mgKOH / g, 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g; preferably, the hydroxyl value of the third polyether polyol is 30-60 mgKOH / g.

[0045] When the hydroxyl value of the third polyether polyol is 30-60 mgKOH / g, the hardness and flexibility of the polyurethane foam potting adhesive are better.

[0046] In some embodiments, the ratio of the isocyanate group in the isocyanate to the hydroxyl value in the third polyether polyol is 14.5-18.5:1, and can be, for example, but not limited to, 14.5:1, 15.5:1, 16.5:1, 17.5:1, 18.5:1.

[0047] Within the above NCO / OH ratio range, the strength and hardness properties of the polyurethane foam potting adhesive are better.

[0048] In the present invention, the test standard for the hydroxyl value of the third polyether polyol is JB / T12008.3-2009.

[0049] In some embodiments, the polyamine is at least one of ethylenediamine, diethylenetriamine, and toluenediamine.

[0050] In some embodiments, the second polyol is at least one of pentaerythritol, xylitol, and sorbitol.

[0051] In some embodiments, the third polyol is at least one of glycerol, trimethylolethane, and trimethylolpropane.

[0052] Specifically, the hydroxyl value of the first polyether polyol is 300-500 mg / KOH, and its test method is JB / T12008.3-2009.

[0053] Specifically, the hydroxyl value of the second polyether polyol is 300-600 mg / KOH, and its test method is JB / T12008.3-2009.

[0054] In some embodiments, the vegetable oil-modified polyol is a vegetable oil-modified polyether polyol and / or polyester polyol prepared from vegetable oil, and the vegetable oil is at least one of rapeseed oil, castor oil, soybean oil, palm oil, and cashew shell oil.

[0055] As a specific example of the vegetable oil-modified polyol, those of BASF can be cited. series products.

[0056] In some embodiments, the amino-silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, phenylaminomethyltriethoxysilane, phenylaminomethyltrimethoxysilane, bis(trimethoxysilylpropyl)amine, and bis(triethoxysilylpropyl)amine.

[0057] In some embodiments, the isocyanate is at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and polyphenyl polymethylene polyisocyanate (PAPI).

[0058] In some embodiments, the thermal conductive filler is at least one of aluminum hydroxide, magnesium hydroxide, alumina, magnesia, boron nitride, and silicon nitride.

[0059] Specifically, the average particle size of the thermal conductive filler is 10 - 50 μm, for example, it can be but not limited to 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm.

[0060] The thermal conductive filler with the above average particle size is beneficial to improving the thermal conductivity of the polyurethane foam potting adhesive.

[0061] In the present invention, the test standard for the average particle size of the thermal conductive filler is YS / T 738.5 - 2020 Analytical methods for aluminium hydroxide for fillers - Part 5: Determination of particle size.

[0062] In some embodiments, the foam stabilizer is a silane stabilizer. As a specific example of the foam stabilizer, Dow Corning DC - 193 can be cited.

[0063] In some embodiments, the blowing agent is water.

[0064] In some embodiments, the flame retardant is a halogen - free phosphate flame retardant. As specific examples of the flame retardant, triethyl phosphate and triphenyl phosphate isopropyl can be cited.

[0065] In the first aspect of the present invention, a preparation method of the polyurethane foam potting adhesive for the battery unit is provided, including the following steps:

[0066] Prepare component A: Mix the first polyether polyol, the second polyether polyol, the vegetable oil - modified polyol, the flame retardant and the thermal conductive filler evenly, then add the foam stabilizer and the blowing agent, and stir evenly to obtain component A;

[0067] Prepare component B: Add the third polyether polyol into the reaction kettle, evacuate for 1 - 2 h at a temperature of 100 - 110 °C, then cool down to 65 - 75 °C, introduce nitrogen, add isocyanate, then react at a temperature of 55 - 65 °C for 3 - 5 h, then cool down to room temperature, and add an amino - silane coupling agent to react for 1 - 2 h to obtain component B;

[0068] Prepare the polyurethane foam potting adhesive for the battery unit: When in use, mix component A and component B evenly to obtain the polyurethane foam potting adhesive for the battery unit.

[0069] Now, the raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0070] The first polyether polyol: The initiator is toluene diamine, the hydroxyl value is 420 - 470 mg / KOH, purchased from Shanghai Jiahua Chemical, brand PURANOL RF TD430;

[0071] The second polyether polyol A: The initiator is pentaerythritol, the hydroxyl value is 535 - 585 mg / KOH, purchased from Shanghai Jiahua Chemical Co., Ltd., brand PURANOL PN560;

[0072] The second polyether polyol B: The initiator is sorbitol, the hydroxyl value is 480 - 520 mg / KOH, purchased from Shanghai Jiahua Chemical Co., Ltd., brand PURANOL RF 635;

[0073] The second polyether polyol C: The initiator is sucrose, the hydroxyl value is 430 - 470 mg / KOH, purchased from Shanghai Jiahua Chemical Co., Ltd., brand PURANOL RF 3450;

[0074] The second polyether polyol D: The initiator is glycerol, the hydroxyl value is 455 - 495 mg / KOH, purchased from Shanghai Jiahua Chemical Co., Ltd., brand PURANOL G303F;

[0075] Castor oil modified polyol: Sovermol 805, BASF;

[0076] Foam stabilizer: Polyether modified silicone compound, DC - 193, Dow Corning;

[0077] Thermal conductivity filler A: Aluminum hydroxide, commercially available;

[0078] Thermal conductivity filler B: Alumina, commercially available;

[0079] Thermal conductivity filler C: Boron nitride, commercially available;

[0080] Flame retardant A: Triethyl phosphate, commercially available;

[0081] Flame retardant B: Isopropyltriphenyl phosphate, commercially available;

[0082] Blowing agent: Purified water, commercially available;

[0083] The third polyether polyol A: The initiator is glycerol, the hydroxyl value is 54.5 - 57.5 mgKOH / g, MN - 3050D, Bluestar Dongda;

[0084] The third polyether polyol B: The initiator is glycerol, the hydroxyl value is 32.5 - 35.5 mgKOH / g, 10LD76EK, Bluestar Dongda;

[0085] The third polyether polyol C: The initiator is glycerol, the hydroxyl value is 26.5 - 29.5 mgKOH / g, EP - 3600, Bluestar Dongda;

[0086] The third polyether polyol D: The initiator is glycerol, the hydroxyl value is 163 - 173 mgKOH / g, MN - 1000, Bluestar Dongda;

[0087] Isocyanate A: MDI: Diphenylmethane diisocyanate, commercially available;

[0088] Isocyanate B: PAPI: Polyphenyl polymethylene polyisocyanate, commercially available;

[0089] Silane coupling agent A: 1124: Bis-(3-trimethoxysilylpropyl)amine, commercially available;

[0090] Silane coupling agent B: γ-Aminopropyltriethoxysilane, commercially available;

[0091] Silane coupling agent C: Vinyltriethoxysilane, commercially available.

[0092] Examples and comparative examples

[0093] The compositions of the polyurethane foam potting adhesives for batteries in the examples and comparative examples are shown in Tables 1 and 2. Among them, NCO:OH refers to the ratio of the isocyanate group in the isocyanate to the hydroxyl value in the third polyether polyol. The preparation methods of the polyurethane foam potting adhesives for batteries in the examples and comparative examples include the following steps:

[0094] Prepare Component A: Mix the first polyether polyol, the second polyether polyol, the vegetable oil-modified polyol, the flame retardant, and the thermal conductive filler evenly, then add the foam stabilizer and the blowing agent, and stir evenly to obtain Component A;

[0095] Prepare Component B: Add the third polyether polyol into the reaction kettle, evacuate for 1 h at a temperature of 105 °C, then cool down to 70 °C, introduce nitrogen, add the isocyanate, then react at a temperature of 60 °C for 4 h, then cool down to room temperature, and add the amino silane coupling agent to react for 1 h to obtain Component B;

[0096] Prepare the polyurethane foam potting adhesive for battery cells: During use, mix Component A and Component B evenly according to a mass ratio of 1:1 to obtain the polyurethane foam potting adhesive for battery cells.

[0097] Table 1

[0098]

[0099]

[0100] Table 2

[0101]

[0102]

[0103] Performance test

[0104] Perform performance tests on the polyurethane foam potting adhesives for battery cells obtained in the examples and comparative examples. The test methods are as follows:

[0105] (1) Creaming time: Refer to the test method for the foaming reaction characteristics of polyurethane raw materials in HG / T 4574-2014;

[0106] (2) Gel time: Refer to the test method for the foaming reaction characteristics of polyurethane raw materials in HG / T 4574-2014;

[0107] (3) Viscosity: Refer to the determination of the viscosity of adhesives in GB / T2794-2002;

[0108] (3) Thermal conductivity: Test according to the standard ASTM C 518;

[0109] (4) Tensile strength: Refer to the determination of the tensile properties of plastics in GB / T 1040-2006;

[0110] (5) Hardness: Determine according to the standard GB / T 531.1-2008;

[0111] (6) Adhesion: Refer to the test method for tensile shear strength in GB / T7124-2008;

[0112] (7) Specific gravity: Refer to the determination of the apparent density of foamed plastics and rubbers in GB / T 6343-2009;

[0113] (8) Flame retardancy: Refer to the flame retardant grade UL-94 standard.

[0114] The test results are shown in Table 3.

[0115] Table 3

[0116]

[0117]

[0118] From the experimental data in Table 3, it can be seen that the creaming time of the polyurethane foam potting adhesive of the present invention is 150 - 500 s, the gel time is 350 - 700 s, the viscosity is 700 - 2200 mPa·s, the thermal conductivity ≥ 0.35 W / (m·K), the adhesive failure form is cohesive failure, the tensile strength is 50 - 70 Shore A, and the specific gravity ≤ 0.4 g / cm 3 , and the flame retardancy grade is V0; it shows that the polyurethane foam potting adhesive of the present invention has the advantages of low viscosity, good fluidity, low specific gravity, high thermal conductivity, high strength and high flexibility.

[0119] As can be seen from Example 3 and Comparative Examples 1-3, in the absence of the first polyether polyol, the rise time of the polyurethane foam potting adhesive becomes slower or even fails to rise, the specific gravity is large, and the hardness is high, which cannot play a better role in weight reduction and buffering protection during the encapsulation process and does not meet the requirements for battery cell encapsulation; in the absence of the thermal conductive filler, the thermal conductivity is low, unable to reach the thermal conductivity of the potting adhesive, and unable to achieve a good heat dissipation effect, thus not meeting the requirements for thermal management of power batteries.

[0120] As can be seen from Examples 3-4 and Comparative Examples 4-5, the functionality of the initiator of the second polyether polyol will affect the tensile strength and hardness of the product. If the functionality of the initiator of the second polyether polyol is too low or too high, the hardness and / or tensile strength of the polyurethane foam potting adhesive will not meet the requirements for battery cell encapsulation.

[0121] As can be seen from Example 3, Example 5 and Comparative Examples 6-7, the hydroxyl value of the third polyether polyol will affect the thermal conductivity, tensile strength and hardness of the product. If the hydroxyl value of the third polyether polyol is too low or too high, it will lead to a decrease in the thermal conductivity of the polyurethane foam potting adhesive, and the hardness and / or tensile strength of the polyurethane foam potting adhesive will not meet the requirements for battery cell encapsulation.

[0122] As can be seen from Example 3, Example 10 and Comparative Examples 8-9, the type and dosage of the silane coupling agent will affect the adhesiveness, tensile strength and hardness of the product. The absence of the silane coupling agent or the use of other types of silane coupling agents to replace the amino silane coupling agent will lead to a decrease in the adhesiveness, tensile strength and hardness of the polyurethane foam potting adhesive.

[0123] Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A polyurethane foam potting adhesive for battery cells, characterized in that: It includes component A and component B; The component A comprises the following components in parts by weight: 10-30 parts of a first polyether polyol, 20-40 parts of a second polyether polyol, 10-30 parts of a vegetable oil-modified polyol, 2-10 parts of a foam stabilizer, 80-120 parts of a thermal conductive filler, 0.1-1 parts of a foaming agent, and 30-60 parts of a flame retardant; The B component includes the following components in parts by weight: 50-70 parts of isocyanate, 20-40 parts of the third polyether polyol, and 1-5 parts of an aminosilane coupling agent; The first polyether polyol uses a polyamine as an initiator; The second polyether polyol uses a second polyol as an initiator, and the functionality of the second polyol is 4-6; The third polyether polyol uses the third polyol as an initiator, and the functionality of the third polyol is 3.

2. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The mass of the first polyether polyol is 5-15% of the total mass of the A component.

3. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The hydroxyl value of the third polyether polyol is 30-80 mgKOH / g.

4. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The ratio of the isocyanate in the isocyanate to the hydroxyl value in the third polyether polyol is 14.5-18.5:

1.

5. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The polyamine is at least one of ethylenediamine, diethylenetriamine and toluenediamine; and / or, the second polyol is at least one of pentaerythritol, xylitol, and sorbitol; And / or, the third polyol is at least one of glycerol, trimethylolethane, and trimethylolpropane.

6. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The vegetable oil-modified polyol is a vegetable oil-modified polyether polyol and / or polyester polyol prepared using vegetable oil as a raw material, and the vegetable oil is at least one of rapeseed oil, castor oil, soybean oil, palm oil, and cashew nut shell oil.

7. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The aminosilane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, anilinomethyltriethoxysilane, anilinomethyltrimethoxysilane, bis(trimethoxysilylpropyl)amine, and bis(triethoxysilylpropyl)amine.

8. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The isocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, and polyphenyl polymethylene polyisocyanate.

9. The polyurethane foam potting adhesive for battery cells according to claim 1, characterized in that: The thermally conductive filler is at least one of aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, boron nitride, and silicon nitride; And / or, the foam stabilizer is a polyether-modified organosilicon compound; And / or, the foaming agent is water; And / or, the flame retardant is a halogen-free phosphate flame retardant.

10. A method for preparing the polyurethane foam potting adhesive for battery cells according to any one of claims 1 to 9, characterized in that: The following steps are involved: Preparation of component A: after uniformly mixing the first polyether polyol, the second polyether polyol, the vegetable oil modified polyol, the flame retardant and the thermal conductive filler, adding the foam stabilizer and the foaming agent, stirring uniformly, to obtain component A; Preparation of component B: adding the third polyether polyol into a reaction kettle, evacuating at a temperature of 100-110° C. for 1-2 hours, cooling to 65-75° C., introducing nitrogen, adding isocyanate, and then reacting at a temperature of 55-65° C. for 3-5 hours, then cooling to room temperature, adding an aminosilane coupling agent and reacting for 1-2 hours to obtain component B; Preparation of polyurethane foam potting glue for battery cells: When in use, component A and component B are evenly mixed to obtain polyurethane foam potting glue for battery cells.

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