A heat and fire insulation material for a battery pack and a preparation method thereof

Abstract

The application provides a heat insulation and fireproof material for a battery pack and a preparation method, which comprises mica tape, double-sided adhesive tape and modified aerogel; the modified aerogel is prepared by cross-linking reaction of chitosan as a monomer and polyethylene glycol with vermiculite as an additive; compared with the existing heat insulation and fireproof material containing aerogel, the mechanical strength is obviously improved; meanwhile, the mica tape is subjected to surface treatment of epoxy resin, and the epoxy groups are bridged on the surface layer of the mica tape, so that the high-temperature resistance and the peeling strength are enhanced; the mechanical strength and the high-temperature resistance of the heat insulation and fireproof material are improved by the combination of the two; the preparation process of the heat insulation and fireproof material is simple, the cost is low, mass production is possible, and the heat insulation and fireproof material has a good application prospect in the field of new energy batteries.

Description

Technical Field

[0001] The present invention relates to the field of new energy electric vehicle parts, and in particular to a heat-insulating and fire-proof material for a battery pack and a preparation method thereof. Background Art

[0002] The core component of new energy electric vehicles currently under development is the lithium battery pack. Lithium batteries generate significant heat during operation and, under extreme conditions, can reach high temperatures, posing a safety hazard to both the vehicle and personnel. Therefore, mica sheets are often assembled on the surface of these batteries. The key features of these mica sheets are their exceptional heat resistance and excellent insulation properties. Electric vehicles can generate high temperatures during abnormal operation, and this property of the mica sheets effectively prevents these temperatures from directly impacting the cab and rear seats, allowing occupants sufficient time to escape. Currently, mica sheet manufacturing rarely combines mica sheets with other materials to enhance their heat resistance, thermal insulation, and lightweight properties. Therefore, combining these sheets with new materials could lead to the development of mica sheets with high-temperature resistance, high insulation, improved thermal insulation, and a lighter weight, potentially expanding their application.

[0003] The patent with publication number CN218215584U discloses a hard thermal protection composite mica part between battery cells, with a stress release layer provided between the first mica plate and the second mica plate, and including an aerogel layer; the patent with publication number CN114193851A discloses a thermal protection composite part between battery cells and a molding process, including a first mica plate, a second mica plate, and a ceramic fiber layer and an aerogel layer; however, the existing aerogel layer used as a flame retardant and heat-insulating material also has many limitations. Organic aerogels are flammable, while inorganic aerogels have poor mechanical properties, which greatly limits the actual application scope and application effect. How to make the aerogel layer have good thermal insulation and fire resistance while also having good mechanical properties has become a technical problem that needs to be solved urgently. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a thermal insulation and fireproof material for battery packs and a preparation method, which solves the problems of single function and low mechanical strength of the aerogel layer in the existing materials.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A heat-insulating and fire-proof material for a battery pack, comprising the following components: mica tape, double-sided tape, and modified aerogel;

[0007] The double-sided tape is provided with two layers, and is respectively arranged on both sides of the modified aerogel;

[0008] The mica tape is provided with two layers, and is respectively arranged on the side away from the modified aerogel of the double-sided adhesive;

[0009] To improve the mechanical properties of the aerogel, further preferably, the modified aerogel is prepared by cross-linking reaction of chitosan as a monomer and polyethylene glycol as an additive.

[0010] Further preferably, the specific preparation method of the modified aerogel comprises the following steps:

[0011] S1, weigh the acetic acid, dilute with water to prepare an acetic acid solution, then weigh the chitosan and add it to the acetic acid solution, ultrasonic for 5-10 min, and stir until no air bubbles are generated in the solution;

[0012] S2, weigh the polyethylene glycol, add it to the chitosan-acetic acid solution in step S1, then add the vermiculite, stir at 20-25℃ for 2-4h, and store the mixture at-18 to-25℃ for 10-14h;

[0013] S3, take out and dry in a drying machine to obtain the modified aerogel.

[0014] Further preferably, the thickness of the aerogel is 0-100mm.

[0015] In order to promote the cross-linking reaction of chitosan and polyethylene glycol, further preferably, the mass concentration of the acetic acid solution in step S1 is 2.5-4%.

[0016] Further preferably, the mass ratio of chitosan to acetic acid solution in step S1 is 1:(3-5).

[0017] Further preferably, the ultrasonic power in step S1 is 300-500W.

[0018] Further preferably, the mass ratio of polyethylene glycol to chitosan in step S2 is (0.3-0.4):1.

[0019] At the same time, in order to control the porosity of the aerogel, further preferably, the mass concentration of vermiculite in the mixture in step S2 is 8-30g / L.

[0020] Further preferably, the mica tape is modified by epoxy resin.

[0021] Further preferably, the preparation method of the mica tape comprises the following steps:

[0022] The epoxy resin is coated on the surface of the mica paper, dried, and molded to obtain the mica tape.

[0023] Further preferably, the epoxy resin is ethylene oxide, propylene oxide and epichlorohydrin.

[0024] More preferably, the molar ratio of ethylene oxide, propylene oxide and epichlorohydrin is (0.25-0.75):(1.5-1.75):1.

[0025] Further preferably, the mica tape has a thickness of 0 to 100 mm.

[0026] On the other hand, the present invention also provides a method for preparing a thermal insulation and fireproof material for a battery pack, comprising the following steps:

[0027] A1. Press both sides of the mica tape with double-sided tape, then cut it into adhesive-backed mica tapes, attach and press the aerogel to obtain a rough sample.

[0028] A2. Punch and shape the rough sample obtained in step A1, cut off the blank edges, and obtain the thermal insulation and fireproof material for the battery pack after processing.

[0029] The heat-insulating and fire-proofing material and preparation method for battery packs of the present invention have the following advantages over the prior art:

[0030] Beneficial effects:

[0031] (1) Among the existing mica tape thermal insulation and fireproof materials using aerogel, organic aerogel is flammable, while inorganic aerogel has poor mechanical properties. The modified aerogel of the present invention is prepared by using chitosan as a monomer, adding vermiculite, and reacting with polyethylene glycol through a cross-linking reaction. It has a three-dimensional network structure, a large specific surface area, and improved mechanical strength. At the same time, new crystals are gathered on the surface, which effectively prevents heat from being transferred inside the material, thereby enhancing the thermal insulation and fireproofing effects.

[0032] (2) Compared with the conventional epoxy resin emulsified and modified and then compounded with mica, the present invention forms a comonomer by ternary polymerization of ethylene oxide, propylene oxide and epichlorohydrin, and then coats the surface of the mica tape to increase the tensile strength and improve the thermal conductivity;

[0033] (3) The flame retardant performance of the thermal insulation and fireproof material for the battery pack of the present invention can reach UL 94V~0; in terms of high temperature resistance, it can be burned by flame at 1200°C without cracking; in terms of thermal insulation performance, the hot surface can be burned by flame at 1200°C, and the cold surface temperature is below 300°C; in terms of lightweight, the density of this thermal insulation and fireproof material for the battery pack is below 1g / cm3; in terms of insulation performance, the electrical strength is greater than 20KV / mm. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Example 1

[0036] A heat-insulating and fire-proof material for a battery pack, comprising the following components: mica tape, double-sided tape, and modified aerogel;

[0037] The specific preparation method of mica tape includes the following steps:

[0038] Ethylene oxide, propylene oxide and epichlorohydrin are polymerized at a molar ratio of 0.25:1.5:1 at 90° C. The obtained epoxy resin is coated on the surface of mica paper, dried, and molded to obtain the mica tape.

[0039] The specific preparation method of the modified aerogel comprises the following steps:

[0040] S1. Weigh 2.5 g of acetic acid and dilute it with 97.5 g of water to make an acetic acid solution with a mass concentration of 2.5%. Then, according to the mass ratio of chitosan to acetic acid solution = 1:3, weigh 33.3 g of chitosan and add it to the acetic acid solution. Ultrasonicate at 300 W for 10 min and stir until the solution is free of bubbles.

[0041] S2, according to the mass ratio of polyethylene glycol to chitosan = 0.3:1, weigh 9.9g of polyethylene glycol, add the chitosan-acetic acid solution in step S1, and then add vermiculite to make the mixture mass concentration 8g / L, stir at 20°C for 4h, and store the mixture at -18°C for 14h after mixing;

[0042] S3. Take out and place in a dryer to dry, thereby obtaining the modified aerogel.

[0043] The method for preparing the thermal insulation and fireproof material for the battery pack comprises the following steps:

[0044] A1. Press both sides of the mica tape with double-sided tape, then cut it into adhesive-backed mica tapes with a width of 1000 mm and a thickness of 100 mm. Then, laminate and press the aerogel to obtain a rough sample.

[0045] A2. The rough sample obtained in step A1 is internally punched and shaped, and the edges of the rough sample are cut off. After processing is completed, the finished product of the thermal insulation and fireproof material for the battery pack is obtained.

[0046] Example 2

[0047] A heat-insulating and fire-proof material for a battery pack, comprising the following components: mica tape, double-sided tape, and modified aerogel;

[0048] The specific preparation method of mica tape includes the following steps:

[0049] Ethylene oxide, propylene oxide and epichlorohydrin are polymerized at a molar ratio of 0.25:1.5:1 at 90° C. The obtained epoxy resin is coated on the surface of mica paper, dried, and molded to obtain the mica tape.

[0050] The specific preparation method of the modified aerogel comprises the following steps:

[0051] S1. Weigh 4 g of acetic acid and dilute it with 96 g of water to make an acetic acid solution. Then, according to the mass ratio of chitosan to acetic acid solution = 1:5, weigh 20 g of chitosan and add it to the acetic acid solution. Ultrasonicate at 500 W for 5 min and stir until the solution is free of bubbles.

[0052] S2, according to the mass ratio of polyethylene glycol to chitosan = 0.4:1, weigh 8g of polyethylene glycol, add the chitosan-acetic acid solution in step S1, and then add vermiculite to make the mixture mass concentration be 30g / L, stir at 25°C for 2h, and store the mixture at -25°C for 10h after mixing;

[0053] S3. Take out and place in a dryer to dry, thereby obtaining the modified aerogel.

[0054] The method for preparing the thermal insulation and fireproof material for the battery pack comprises the following steps:

[0055] A1. Press both sides of the mica tape with double-sided tape, then cut it into adhesive-backed mica tapes with a width of 1000 mm and a thickness of 100 mm. Lay it on the aerogel and press it tightly to obtain a rough sample.

[0056] A2. The rough sample obtained in step A1 is internally punched and shaped, and the edges of the rough sample are cut off. After processing is completed, the finished product of the thermal insulation and fireproof material for the battery pack is obtained.

[0057] Example 3

[0058] A heat-insulating and fire-proof material for a battery pack, comprising the following components: mica tape, double-sided tape, and modified aerogel;

[0059] The specific preparation method of mica tape includes the following steps:

[0060] Ethylene oxide, propylene oxide and epichlorohydrin are polymerized at a molar ratio of 0.25:1.5:1 at 90° C. The obtained epoxy resin is coated on the surface of mica paper, dried, and molded to obtain the mica tape.

[0061] The specific preparation method of the modified aerogel comprises the following steps:

[0062] S1. Weigh 3 g of acetic acid and dilute it with 97 g of water to make an acetic acid solution. Then, weigh 25 g of chitosan and add it to the acetic acid solution in a mass ratio of 1:4. Ultrasonicate at 400 W for 8 min and stir until the solution is free of bubbles.

[0063] S2, according to the mass ratio of polyethylene glycol to chitosan = 0.36:1, weigh 9 g of polyethylene glycol, add the chitosan-acetic acid solution in step S1, and then add vermiculite to make the mixture mass concentration be 15 g / L, stir at 22 ° C for 3 h, and store the mixture at -20 ° C for 12 h after mixing;

[0064] S3. Take out and place in a dryer to dry, thereby obtaining the modified aerogel.

[0065] The method for preparing the thermal insulation and fireproof material for the battery pack comprises the following steps:

[0066] A1. Press both sides of the mica tape with double-sided tape, then cut it into adhesive-backed mica tapes with a width of 1000 mm and a thickness of 100 mm. Lay it on the aerogel and press it tightly to obtain a rough sample.

[0067] A2. The rough sample obtained in step A1 is internally punched and shaped, and the edges of the rough sample are cut off. After processing is completed, the finished product of the thermal insulation and fireproof material for the battery pack is obtained.

[0068] Example 4

[0069] A thermal insulation and fireproof material for a battery pack, which differs from Example 1 in that, during the preparation of the mica tape, ethylene oxide, propylene oxide, and epichlorohydrin are polymerized at a molar ratio of 0.75:1.75:1 at 90°C.

[0070] Example 5

[0071] A thermal insulation and fireproof material for a battery pack, which differs from Example 1 in that, during the preparation of the mica tape, ethylene oxide, propylene oxide, and epichlorohydrin are polymerized at a molar ratio of 0.5:1.5:1 at 90°C.

[0072] Comparative Example 1

[0073] A thermal insulation and fireproof material for a battery pack, which differs from Example 1 in that the aerogel used is conventional silica aerogel and has not been modified.

[0074] Comparative Example 2

[0075] A heat-insulating and fire-proof material for a battery pack, which differs from Example 1 in that the surface of the mica tape used is not modified with epoxy resin.

[0076] Comparative Example 3

[0077] A heat and fire insulation material for battery pack, which is different from example 1 in that the used modified aerogel additive is attapulgite.

[0078] Comparative example 4

[0079] A heat and fire insulation material for battery pack, which is different from example 1 in that the mass ratio of chitosan to acetic acid solution in the step S1 of the modified aerogel is 1:7.

[0080] Comparative example 5

[0081] A heat and fire insulation material for battery pack, which is different from example 1 in that the mica tape is replaced by glass cloth.

[0082] The mica tape heat and fire insulation materials obtained from the above examples 1-3 and comparative examples 1-5 are tested for performance, including flame retardant performance, high temperature resistance, electrical strength and peel strength test,

[0083] Flame retardant grade UL94 determination: according to the national standard GB / T2048-1996 "plastic combustion performance test method horizontal and vertical method", CZF-3 type vertical combustion tester is used; electrical strength test: according to the relevant test standards of national standard GB / T5019.2-2009, Φ25mm / Φ75mm cylindrical electrode, 1.0kV / s fast voltage rise, electrical strength test is carried out; peel strength test: according to the test standards of national standard GB / T7122, test is carried out;

[0084] Table 1 flame retardant and high temperature resistance performance test of mica tape heat and fire insulation material

[0085]

[0086] Table 2 peel strength and electrical strength test of mica tape heat and fire insulation material

[0087]

[0088]

[0089] As can be seen from the above, compared with comparative example 1, the peel strength, flame retardant grade and thermal conductivity of examples 1-5 are obviously improved, and compared with comparative example 2, the high temperature resistance of examples 1-5 is better.

[0090] The above only describes the preferred embodiments of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal insulation and fireproof material for a battery pack, characterized in that: Including mica tape, double-sided tape and modified aerogel, among which, The double-sided tape is provided with two layers, and is respectively arranged on both sides of the modified aerogel; The mica tape is provided with two layers, and is respectively arranged on the side of the double-sided tape away from the modified aerogel; The modified aerogel is prepared by cross-linking chitosan with polyethylene glycol using chitosan as a monomer and vermiculite as an additive; The steps include: S1. Weigh acetic acid, dilute with water to prepare acetic acid solution, then weigh chitosan and add it to the acetic acid solution, sonicate for 5-10 minutes, and stir until no bubbles are generated in the solution; the mass ratio of chitosan to acetic acid solution in step S1 is 1:(3-5) S2. Weigh polyethylene glycol, add the chitosan-acetic acid solution in step S1, and then add vermiculite. Stir at 20-25° C. for 2-4 h. Mix the mixture and store at -18- -25° C. for 10-14 h. S3, taking out and placing in a dryer to dry, thereby obtaining a modified aerogel; The mica tape is modified with epoxy resin, comprising the following steps: coating epoxy resin on the surface of mica paper, drying, and molding to obtain the mica tape; The epoxy resins are ethylene oxide, propylene oxide and epichlorohydrin.

2. The thermal insulation and fireproof material for battery pack according to claim 1, characterized in that: The mass concentration of the acetic acid solution in step S1 is 2.5-4%.

3. The thermal insulation and fireproof material for battery pack according to claim 1, characterized in that: The mass ratio of polyethylene glycol to chitosan in step S2 is (0.3-0.4):

1.

4. The thermal insulation and fireproof material for battery pack according to claim 1, characterized in that: The mass concentration of vermiculite in the mixture in step S2 is 8-30 g / L.

5. The thermal insulation and fireproof material for battery pack according to claim 1, characterized in that: The molar ratio of ethylene oxide, propylene oxide and epichlorohydrin is (0.25~0.75): (1.5~1.75):

1.

6. A method for preparing a thermal insulation and fireproof material for a battery pack, characterized in that: The thermal insulation and fireproofing material for battery packs according to claims 1 to 5 is used, comprising the following steps: A1. Press both sides of the mica tape with double-sided tape, then cut it into adhesive-backed mica tapes, attach and press the aerogel to obtain a rough sample. A2. Punch and shape the rough sample obtained in step A1, cut off the blank edges, and obtain the thermal insulation and fireproof material for the battery pack after processing.

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