Adhesive sealing organic silica gel for battery pack and preparation method thereof

Abstract

The present application relates to the field of sealants and discloses a bonding and sealing organic silicone for battery packs and its preparation method. The bonding and sealing organic silicone consists of components AB. Component A is made from the following raw materials in parts by weight: 80-100 parts of bis-hydroxy-terminated polydimethylsiloxane, 35-45 parts of filler, 1-3 parts of antioxidant, and 0.2-0.4 parts of catalyst; component B is made from the following raw materials in parts by weight: 30-40 parts of bis-hydroxy-terminated polydimethylsiloxane, 5-10 parts of cross-linking agent, 4-8 parts of tackifier, and 20-30 parts of flame retardant; the cross-linking agent is composed of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine; the tackifier is composed of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether, and cyclohexane-1,2-dicarboxylic acid diglycidyl ester. Advantages: When used for battery pack shells, the battery pack has good bonding stability when facing long-term high and low temperature environments.

Description

Technical Field

[0001] The present application relates to the field of sealants, and more specifically, to an adhesive sealing organic silica gel for battery packs and a preparation method thereof. Background Art

[0002] As the power source for new energy vehicles, the stability and safety of battery pack performance are crucial to their quality. During battery pack assembly, sealant is required to bond the battery pack housing. The adhesive used to bond and seal the battery pack housing must possess a range of key properties, including excellent adhesion, temperature resistance, and sealing properties, to ensure the battery pack's operational stability in high-intensity and complex environments.

[0003] At present, the adhesives used in battery pack shells are generally room-temperature curing organic silicone adhesives, which are generally made of components such as polysiloxane containing active groups, cross-linking agents, fillers, additives and curing agents. They can achieve surface curing within a few to ten minutes and can be fully cured at room temperature within 24 to 48 hours. After full curing, they have good bonding and sealing properties.

[0004] However, during the long-term operation of new energy vehicles, battery packs often face extreme high or low temperature environments, which makes the battery pack shell prone to unstable fitting, reducing the service life and safety of the battery pack. Summary of the Invention

[0005] In order to solve the problem that organic silicone adhesives used for bonding battery pack shells are prone to unstable bonding when the battery pack faces extreme high or low temperature environments, the present application provides a bonding and sealing organic silicone for battery packs and a preparation method thereof.

[0006] In a first aspect, the present application provides an adhesive sealing organic silicone for a battery pack, which adopts the following technical solution:

[0007] A bonding and sealing organic silica gel for battery packs, consisting of component A and component B, wherein component A is prepared from the following raw materials in parts by weight: 80-100 parts of bishydroxy-terminated polydimethylsiloxane, 35-45 parts of filler, 1-3 parts of antioxidant, and 0.2-0.4 parts of catalyst; component B is prepared from the following raw materials in parts by weight: 30-40 parts of bishydroxy-terminated polydimethylsiloxane, 5-10 parts of cross-linking agent, 4-8 parts of tackifier, and 20-30 parts of flame retardant; the cross-linking agent is composed of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine; and the tackifier is composed of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether, and cyclohexane-1,2-dicarboxylic acid diglycidyl ester.

[0008] By adopting the above technical solution, the adhesive sealing organic silicone for battery packs prepared in this application is a two-component room temperature vulcanized organic silicone with excellent bonding performance and temperature resistance, which can effectively improve the stability and safety of battery packs in extreme environments such as high and low temperatures. This application uses dihydroxy-terminated polydimethylsiloxane as a matrix. The dihydroxy-terminated polydimethylsiloxane gives the organic silicone good bonding performance, and is then compounded with a cross-linking agent and a thickener. Under the action of a catalyst, the cross-linking agent and the dihydroxy-terminated polydimethylsiloxane can react stably at room temperature. Under the synergistic action of the thickener, a macromolecular substance with an interwoven network structure is formed. The organic silicone prepared in this way has good bonding stability; the filler can be evenly dispersed in the interwoven network structure, further improving the structural density of the cured organic silicone; the flame retardant can give the organic silicone good flame retardancy, which is suitable for battery packs; the antioxidant can improve the aging resistance of the organic silicone and increase its service life; the two-component formula system has good storage and production stability.

[0009] Preferably, the cross-linking agent is composed of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine in a weight ratio of (2-3):1.

[0010] By adopting the above technical solution, pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine in a relatively optimal weight ratio are used as cross-linking agents. The two have a good synergistic effect and can react with bis-hydroxy-terminated polydimethylsiloxane under the action of a catalyst to increase the cross-linking density of the organic silicone, thereby improving the adhesion performance and temperature aging resistance of the organic silicone, improving the adhesion stability and sealing reliability of the battery pack shell in high or low temperature environments, and thereby extending the overall service life and safety of the battery pack.

[0011] Preferably, the tackifier is composed of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether and cyclohexane-1,2-dicarboxylic acid diglycidyl ester in a weight ratio of 1:(1-2):(0.5-1).

[0012] By adopting the above technical solution, polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether and cyclohexane-1,2-dicarboxylic acid diglycidyl ester in an optimal weight ratio are used as thickeners, which can produce a good synergistic effect with the cross-linker and dihydroxy-terminated polydimethylsiloxane, giving the silicone rubber better softness, bonding strength and durability, ensuring good bonding stability under extreme conditions.

[0013] Preferably, the molecular weight of the bishydroxy-terminated polydimethylsiloxane in component A is 5000-6000 and the viscosity is 10000-20000 mPa·s.

[0014] Preferably, the molecular weight of the bishydroxy-terminated polydimethylsiloxane in component B is 400-800, and the viscosity is 1000-3000 mPa·s.

[0015] By adopting the above technical solution, the molecular weight of the dihydroxy-terminated polydimethylsiloxane of component A is optimized to 5000-6000 and the viscosity is 10000-20000 mPa·s. The molecular weight of the dihydroxy-terminated polydimethylsiloxane of component B is optimized to 400-800 and the viscosity is 1000-3000 mPa·s. When components A and B are mixed and cured, under the action of the catalyst, the organic silicone system has good cross-linking uniformity, and can further improve the dispersion uniformity of the filler, further improve the structural density of the cross-linked organic silicone, and then improve the bonding stability of the organic silicone in high or low temperature environments, thereby improving the stability and safety of the battery pack shell.

[0016] Preferably, the filler is nano calcium carbonate and / or fumed silica.

[0017] By adopting the above technical solution, the above filler can improve the mechanical strength of the organic silica gel, enhance its temperature resistance and anti-aging properties, thereby improving the stability and safety of the battery pack shell.

[0018] Preferably, the catalyst is dibutyltin dilaurate and / or stannous octoate.

[0019] By adopting the above technical solution, the above catalyst can effectively promote the reaction between the dihydroxy-terminated polydimethylsiloxane and the cross-linking agent, thereby improving the curing efficiency of the organic silicone.

[0020] Preferably, the flame retardant is one or a combination of aluminum hydroxide, magnesium hydroxide, magnesium oxide and zinc borate.

[0021] By adopting the above technical solution, the flame retardant has good thermal stability and decomposition heat absorption characteristics. It can quickly absorb heat and release water vapor at high temperatures, lower the temperature, inhibit the occurrence and development of combustion reactions, and significantly improve the overall fire resistance of the battery pack.

[0022] Preferably, the volume ratio of the component A to the component B during use is 10:(2-3).

[0023] By adopting the above technical solution, the volume ratio of component A and component B during use is optimized, the mixing uniformity and reaction stability of the adhesive are improved, and the bonding strength and sealing of the silicone gel to the battery pack shell are enhanced.

[0024] In a second aspect, the present application provides a method for preparing an adhesive sealing organic silicone for a battery pack, which adopts the following technical solution:

[0025] A method for preparing an adhesive sealing organic silica gel for a battery pack comprises the following steps:

[0026] Preparation of component A: Mix the dihydroxy-terminated polydimethylsiloxane, filler, antioxidant and catalyst evenly, and perform vacuum degassing to obtain component A;

[0027] Preparation of component B: Dihydroxy-terminated polydimethylsiloxane, a cross-linking agent, a tackifier and a flame retardant are uniformly mixed and vacuum degassed to obtain component B.

[0028] By adopting this technical solution, during the preparation of component A, the bishydroxy-terminated polydimethylsiloxane is uniformly mixed with the filler, antioxidant, and catalyst and then subjected to a vacuum degassing treatment. During the preparation of component B, the bishydroxy-terminated polydimethylsiloxane is uniformly mixed with the crosslinker, tackifier, and flame retardant and then subjected to a vacuum degassing treatment. This effectively improves the mixing uniformity of the components, reduces bubble generation, and ensures the flatness and density of the bonding surface. The resulting silicone rubber exhibits excellent storage stability and ease of use.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. The bonding and sealing organic silicone used for battery packs in the present application is a two-component room temperature vulcanizing adhesive. Component A consists of dihydroxy-terminated polydimethylsiloxane, filler, antioxidant and catalyst, and component B consists of dihydroxy-terminated polydimethylsiloxane, cross-linker, tackifier and flame retardant. When used, components A and B are mixed in proportion. Under the action of the catalyst, the dihydroxy-terminated polydimethylsiloxane and the cross-linker react. Under the synergistic action of the tackifier, an interwoven network molecular structure is formed. The filler and flame retardant are evenly dispersed in the interwoven network molecular structure system. After curing, an organic silicone layer with good bonding performance and impact resistance is formed. When used in battery packs, the battery packs have good bonding stability when facing high and low temperatures and subjected to long-term vibration and shock.

[0031] 2. By using a preferred weight ratio of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine as a crosslinker, and using a preferred weight ratio of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether and cyclohexane-1,2-dicarboxylic acid diglycidyl ester as a tackifier, it has a good synergistic effect with bis-hydroxy-terminated polydimethylsiloxane, thereby improving the bonding performance and impact resistance of the prepared silicone rubber.

[0032] 3. By further optimizing the viscosity and molecular weight parameters of the dihydroxy-terminated polydimethylsiloxane in components A and B, the density of the network molecular structure formed by the organic silicone cured at room temperature is further improved, and the bonding performance and impact resistance of the organic silicone are further improved. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the embodiments.

[0034] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and examples of this application can be obtained from commercial sources, including but not limited to the following models and manufacturers. Raw materials with equivalent performance can be used:

[0035] 1. Pentaerythritol triallyl ether: CAS No. 1471-17-6, content 99%;

[0036] 2. Bis[3-(triethoxysilyl)propyl]amine: CAS No. 13497-18-2, content 99%;

[0037] 3. Polyisobutylene succinic anhydride: PIBS, molecular weight 1000, Chenghua New Materials;

[0038] 4. 3-Aminopropanol vinyl ether: CAS No. 66415-55-2, content 99%;

[0039] 5. Cyclohexane-1,2-dicarboxylic acid diglycidyl ester: CAS No. 5493-45-8, content 99%;

[0040] 6. Nano calcium carbonate: 50-100nm;

[0041] 7. Fumed silica: 50-100nm;

[0042] 8. Bis-hydroxy terminated polydimethylsiloxane: The molecular structure is as follows:

[0043]

[0044] Example

[0045] Example 1

[0046] Example 1 discloses an adhesive sealing organic silica gel for a battery pack, comprising the following steps:

[0047] Preparation of component A: 8 kg of dihydroxy-terminated polydimethylsiloxane, 3.5 kg of fumed silica as filler, 0.1 kg of antioxidant (composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1), and 0.02 kg of dibutyltin dilaurate as a catalyst were mixed at a mixing rate of 800 r / min for 60 min, and then vacuum degassed at a vacuum degree of -0.08 MPa for 20 min to prepare component A;

[0048] Preparation of component B: 3 kg of bis-hydroxy-terminated polydimethylsiloxane, 0.5 kg of a crosslinker (composed of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine in a weight ratio of 2:1), 0.8 kg of a tackifier (composed of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether, and cyclohexane-1,2-dicarboxylic acid diglycidyl ester in a weight ratio of 1:1:0.5), and 1 kg of a flame retardant (composed of magnesium hydroxide and aluminum hydroxide in a weight ratio of 1:1) were mixed at a mixing rate of 600 r / min for 40 min, and then vacuum degassed at a vacuum degree of -0.08 MPa for 20 min to prepare component B;

[0049] The molecular weight of the dihydroxy-terminated polydimethylsiloxane in component A is 10,000 and the viscosity is 40,000 mPa·s;

[0050] The molecular weight of the bishydroxy-terminated polydimethylsiloxane in component B is 400 and the viscosity is 1000 mPa·s.

[0051] Example 2-3

[0052] The difference between Example 2-3 and Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0053] Table 1 Parameters of Examples 1-3

[0054]

[0055]

[0056] Example 4

[0057] The difference between Example 4 and Example 1 is that the molecular weight of the bis-hydroxy-terminated polydimethylsiloxane in component A of Example 4 is 5000 and the viscosity is 10000 mPa·s. Other components are the same as those in Example 1.

[0058] Example 5

[0059] The difference between Example 5 and Example 1 is that the molecular weight of the bis-hydroxy-terminated polydimethylsiloxane in component A of Example 4 is 6000 and the viscosity is 20000 mPa·s. Other components are the same as those in Example 1.

[0060] Example 6

[0061] The difference between Example 6 and Example 2 is that the molecular weight of the bis-hydroxy-terminated polydimethylsiloxane in component B in Example 6 is 800 and the viscosity is 3000 mPa·s. Other components are the same as those in Example 1.

[0062] Example 7

[0063] The difference between Example 7 and Example 1 is that the weight ratio of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine is 0.5:1, and the other steps are the same as those of Example 1.

[0064] Example 8

[0065] The difference between Example 8 and Example 1 is that the weight ratio of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether and cyclohexane-1,2-dicarboxylic acid diglycidyl ester is 3:1:2, and the rest is the same as Example 1.

[0066] Comparative Example

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that an equal amount of pentaerythritol triallyl ether is replaced by methyl tributylanoxime silane, and the other ingredients are the same as those in Example 1.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Example 1 is that an equal amount of bis[3-(triethoxysilyl)propyl]amine is replaced by ethyl orthosilicate, and the other components are the same as those in Example 1.

[0071] Comparative Example 3

[0072] The difference between Comparative Example 3 and Example 1 is that an equal amount of 3-aminopropanol vinyl ether is replaced by vinyltrimethoxysilane, and the rest is the same as Example 1.

[0073] Comparative Example 4

[0074] The difference between Comparative Example 4 and Example 1 is that an equal amount of cyclohexane-1,2-dicarboxylic acid diglycidyl ester is replaced by 3-aminopropanol vinyl ether, and the rest is the same as Example 1.

[0075] Comparative Example 5

[0076] The difference between Comparative Example 5 and Example 1 is that an equal amount of cyclohexane-1,2-dicarboxylic acid diglycidyl ester is used, and the rest is the same as Example 1.

[0077] Performance testing

[0078] The following performance tests were conducted on the adhesive sealing silicone rubber for battery packs prepared in Examples 1-8 and Comparative Examples 1-5: 1. Tensile shear strength test:

[0079] Referring to the test method in GB / T 7124-2008 "Determination of tensile shear strength of adhesives", mix components A and B in a volume ratio of 10:3, apply and test the fully cured tensile shear strength (unit: MPa) at a curing temperature of 25°C and a curing time of 48 hours. Test and record the test results.

[0080] 2. Reliability test:

[0081] Mix component A and component B in a volume ratio of 10:3 and add 40g / m 2 The coating amount was applied to the stainless steel battery pack shell. After curing for 48 hours at a temperature of 25°C, the following properties were tested:

[0082] (1) Thermal shock test:

[0083] Refer to the test method in GB / T 2423.22-2012, test at -40°C and 125°C, switch for 30 seconds, and test for 500 hours. Afterwards, observe whether the battery pack shell shows any signs of whitening, debonding, or warping, and test and record the test results.

[0084] (2) High temperature and high humidity test:

[0085] Refer to the test method in GB / T 2423.50-2012 and test at 85°C and 85% humidity for 1008 hours. Observe the battery pack shell for any debonding or warping, and record the test results.

[0086] (3) Low temperature test:

[0087] Refer to the test method in GB / T 2423.2-2008 and test at -40°C for 1008h. Then observe whether the battery pack shell has cracks or whitening, and test and record the test results.

[0088] The following are performance test data of the adhesive sealing organic silica gel for battery packs prepared in Examples 1-8 and Comparative Examples 1-5. See Table 2 below for details.

[0089] Table 2 Performance test data of Examples 1-8 and Comparative Examples 1-5

[0090]

[0091]

[0092] Combining Examples 1-3 and 7, Comparative Examples 1-2, and Table 2, it can be concluded that using the preferred weight ratio of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine as crosslinkers can improve the adhesive stability of the resulting silicone rubber in high and low temperature environments. Compared to Example 7, Example 1 optimizes the ratio of the two, resulting in improved tensile shear strength of the resulting silicone rubber. Comparative Examples 1-2, however, change the type and ratio of the crosslinkers compared to Example 1, resulting in reduced tensile shear strength of the resulting silicone rubber, and both samples failed reliability testing.

[0093] Combining Examples 1-3 with Example 8, Comparative Examples 3-5, and Table 2, it can be concluded that using the preferred weight ratio of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether, and cyclohexane-1,2-dicarboxylic acid diglycidyl ester as tackifiers can improve the bonding stability of the resulting silicone rubber in high and low temperature environments. Compared to Example 8, Example 1 optimizes the ratio of the three, resulting in improved tensile shear strength of the resulting silicone rubber. However, compared to Example 1, Comparative Examples 3-5 change the type and ratio of the tackifiers, resulting in reduced tensile shear strength of the resulting silicone rubber, and all failed reliability tests.

[0094] Combining Examples 1-3 and Examples 4-6 with Table 2, it can be concluded that further optimizing the viscosity and molecular weight of the bis-hydroxy-terminated polydimethylsiloxane of component A and the bis-hydroxy-terminated polydimethylsiloxane of component B of the present application can further improve the adhesive properties of the prepared silicone rubber.

[0095] In summary, the specific dihydroxy-terminated polydimethylsiloxane of the present application is compounded with the cross-linker and thickener of the present application to produce an organic silicone with good bonding properties. When used in a battery pack, it has good bonding stability, can operate stably in high and low temperature environments, and improves the safety and life of the battery pack.

[0096] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An adhesive sealing organic silica gel for battery pack, characterized in that: The invention comprises component A and component B, wherein the component A is prepared from the following raw materials in parts by weight: 80-100 parts of bishydroxy-terminated polydimethylsiloxane, 35-45 parts of filler, 1-3 parts of antioxidant, and 0.2-0.4 parts of catalyst; the component B is prepared from the following raw materials in parts by weight: 30-40 parts of bishydroxy-terminated polydimethylsiloxane, 5-10 parts of cross-linking agent, 4-8 parts of tackifier, and 20-30 parts of flame retardant; the cross-linking agent is composed of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine; and the tackifier is composed of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether, and cyclohexane-1,2-dicarboxylic acid diglycidyl ester.

2. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The crosslinking agent consists of pentaerythritol triallyl ether and bis[3-(triethoxysilyl)propyl]amine in a weight ratio of (2-3):

1.

3. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The tackifier consists of polyisobutylene succinic anhydride, 3-aminopropanol vinyl ether and cyclohexane-1,2-dicarboxylic acid diglycidyl ester in a weight ratio of 1:(1-2):(0.5-1).

4. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The molecular weight of the bishydroxy-terminated polydimethylsiloxane in component A is 5000-6000, and the viscosity is 10000-20000 mPa·s.

5. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The molecular weight of the bishydroxy-terminated polydimethylsiloxane in the component B is 400-800, and the viscosity is 1000-3000 mPa·s.

6. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The filler is nano calcium carbonate and / or fumed silica.

7. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate and / or stannous octoate.

8. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The flame retardant is one or a combination of aluminum hydroxide, magnesium hydroxide, magnesium oxide and zinc borate.

9. The adhesive sealing organic silica gel for battery pack according to claim 1, characterized in that: The volume ratio of the component A to the component B during use is 10:(2-3).

10. A method for preparing an adhesive sealing organic silica gel for a battery pack according to any one of claims 1 to 9, characterized in that: The following steps are involved: Preparation of component A: Mix the dihydroxy-terminated polydimethylsiloxane, filler, antioxidant and catalyst evenly, and perform vacuum degassing to obtain component A; Preparation of component B: Dihydroxy-terminated polydimethylsiloxane, a cross-linking agent, a tackifier and a flame retardant are uniformly mixed and vacuum degassed to obtain component B.

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