A heat-insulating and ablation-resistant composite material, its preparation method and application

Abstract

This invention discloses a heat-insulating and ablation-resistant composite material, comprising a matrix plate and a silicon carbide fiber-reinforced resin composite material pressed onto the matrix plate. The silicon carbide fiber-reinforced resin composite material is obtained by coating both sides of a silicon carbide fiber cloth / felt with a heat-insulating and ablation-resistant modified resin and then impregnating and curing it. The heat-insulating and ablation-resistant modified resin is prepared by reacting 20%-60% by weight of epoxy resin, 2%-10% by weight of curing agent, 5%-15% by weight of catalyst, 10%-15% by weight of nucleating agent, 3%-5% by weight of foaming agent, 15%-20% by weight of flame retardant, and 5%-15% by weight of additives. The heat-insulating and ablation-resistant composite material provided by this invention achieves integrated heat insulation and ablation resistance, can meet the requirements for ablation resistance and heat insulation at a high temperature of 1300℃, and can maintain the back plate temperature below 300℃ after continuous ablation at 1300℃ for 30 minutes.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and particularly relates to a heat-insulating and ablation-resistant composite material, its preparation method, and its application. Background Technology

[0002] The power battery system (battery pack) is the power source of a new energy vehicle and one of its most critical components. A battery pack generally consists of battery modules, an electrical system, a thermal management system, a battery management system, and structural components. The main function of the power battery pack casing is to support the battery modules, electrical modules, cooling modules, and other components of the power battery system, while protecting the battery and electrical system from damage by external impacts and compression. It plays a crucial role in the safety protection of the battery pack. To ensure the safety of the power battery, the power battery pack casing needs to withstand various complex operating conditions and meet requirements for strength and rigidity.

[0003] Currently, the battery pack casing generally uses mica sheets as the ablation-resistant layer, and the cover plate and the fireproof and heat-insulating layer are separate. This solution has the following shortcomings: (1) The fire resistance temperature of the battery pack protective material made of mica sheets is generally 800℃. In the future, as the energy density of the battery increases, the fire resistance temperature requirement of the battery will reach 1300℃, and the existing mica sheets will be difficult to meet the requirements of high-temperature use; (2) The thickness of the traditional battery pack casing is 5-8mm, and with the addition of 1mm of mica sheets, the total thickness will reach 6-9mm. The battery pack will be heavy, the power consumption will increase, the range will be reduced, which is not conducive to the energy-saving, environmental protection and lightweight development of electric vehicles.

[0004] With the development of new energy vehicles, people's requirements for the driving range of new energy vehicles are constantly increasing, and the requirements for the heat insulation and high temperature resistance of power batteries as well as their lightweighting are constantly increasing. However, the existing battery pack shell materials generally only have heat insulation properties or only have ablation resistance properties, which are difficult to achieve both heat insulation and ablation resistance properties at 1300℃, and cannot meet the requirements for ablation resistance and heat insulation at 1300℃. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a heat insulation and ablation resistant integrated composite material that can not only meet the ablation resistance and heat insulation problems under high temperature conditions, but also achieve lightweight composite material, and can meet the requirement that the back plate temperature is below 300°C after ablation at 1300°C for 30 minutes.

[0006] One objective of this invention is to provide a heat-insulating and ablation-resistant composite material to address the current need for higher fire temperatures and ablation resistance. Another objective of this invention is to provide a method for preparing the heat-insulating and ablation-resistant composite material.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A heat-insulating and ablation-resistant composite material includes a matrix plate and a silicon carbide fiber-reinforced resin composite material pressed onto the matrix plate. The silicon carbide fiber-reinforced resin composite material is obtained by coating both sides of a silicon carbide fiber cloth / felt with a heat-insulating and ablation-resistant modified resin and impregnating it with the modified resin, followed by curing.

[0009] The heat-insulating and ablation-resistant modified resin is prepared by mixing 20%-60% by weight of epoxy resin, 2%-10% by weight of curing agent, 5%-15% by weight of catalyst, 10%-15% by weight of charring agent, 3%-5% by weight of foaming agent, 15%-20% by weight of flame retardant, and 5%-15% by weight of additives.

[0010] The ablation-resistant modified resin used in this invention can simultaneously foam and carbonize at temperatures above 300℃ to form an inorganic foam matrix, effectively isolating heat conduction and blocking flame erosion. Silicon carbide fiber cloth / felt possesses excellent high-temperature oxidation resistance and good mechanical properties at high temperatures. This invention combines the ablation-resistant modified resin and silicon carbide fiber cloth / felt. On one hand, the ablation-resistant modified resin can simultaneously foam and carbonize at temperatures above 300℃ to form an inorganic foam matrix, increasing the thickness of the composite material and thus improving the thermal insulation effect. Simultaneously, the silicon carbide fiber cloth / felt provides good strength support for the foam structure, increasing cell strength and improving the structural strength of the ablation-resistant modified resin after foaming. On the other hand, the silicon carbide fiber cloth / felt can solidify the ablation-resistant modified resin foamed under high-temperature conditions, controlling its foaming ratio. Simultaneously, the foamed structure can prolong the oxidation time of the silicon carbide fiber cloth / felt under high-temperature conditions, thereby improving the overall ablation resistance of the composite material. The heat-insulating and ablation-resistant composite material prepared by this invention is a battery pack shell material that integrates heat insulation and ablation resistance. It uses a heat-insulating and ablation-resistant modified resin as an ablation-resistant matrix and silicon carbide fiber cloth / felt as a supporting skeleton. The two work together to achieve integrated heat insulation and ablation resistance. It can not only meet the ablation resistance and heat insulation problems under high temperature conditions, but also achieve the composite material to be lightweight and meet the mechanical performance requirements under high temperature conditions.

[0011] In a further preferred embodiment, the silicon carbide fiber cloth / felt is silicon carbide fiber cloth or silicon carbide fiber felt, or a combination of silicon carbide fiber cloth and silicon carbide fiber felt.

[0012] In a further preferred embodiment, the volume ratio of silicon carbide fiber cloth to silicon carbide fiber felt in the silicon carbide fiber cloth / felt is 1:5 to 5:1. When the volume ratio of silicon carbide fiber cloth to silicon carbide fiber felt is within this range, the prepared battery pack shell material, after being ablated for 30 minutes, shows no delamination, cracking, or burn-through. After ablation at 1300℃ for 30 minutes, the backplate temperature of the composite material is below 250℃, demonstrating better heat insulation and ablation resistance.

[0013] In a further preferred embodiment, the silicon carbide fiber cloth is a second-generation silicon carbide fiber cloth; the silicon carbide fiber felt is a second-generation silicon carbide fiber felt.

[0014] In a further preferred embodiment, the epoxy etching resin is one or more of, but not limited to, bisphenol A type epoxy resin, bisphenol F type epoxy resin, organosilicon modified epoxy resin, and hydrogenated bisphenol A type epoxy resin.

[0015] In a further preferred embodiment, the curing agent is not limited to one of tetraethylenepentamine, diethylenetriamine, polyethyleneimine, or polyamide.

[0016] In a further preferred embodiment, the catalyst is not limited to one of ammonium dihydrogen phosphate, borate, or organophosphate.

[0017] In a further preferred embodiment, the carbonizing agent is one or more of epoxy resin, phenolic resin, aldehyde-ketone resin, starch, and cellulose, not limited to.

[0018] In a further preferred embodiment, the foaming agent is not limited to one of melamine, urea, or azodicarbonamide.

[0019] In a further preferred embodiment, the flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, aluminum oxide, antimony trioxide, and zinc oxide, not limited to these.

[0020] In a further preferred embodiment, the additive is one or more of the following, but not limited to, silicone oil, polydimethylsiloxane, alkyl-modified organosiloxane, and polyether polyester-modified organosiloxane.

[0021] In a further preferred embodiment, the substrate is not limited to one of aluminum plate, steel plate, or fiber-reinforced resin-based composite board.

[0022] This invention also provides a method for preparing a heat-insulating and ablation-resistant battery pack, the preparation steps of which are as follows:

[0023] (a) Prepare the components according to the formula of the heat-insulating and ablation-resistant modified resin, stir and mix them evenly, and set aside for later use;

[0024] (b) The heat-insulating and ablation-resistant modified resin obtained in step (a) is evenly sprayed onto the upper and lower surfaces of the silicon carbide fiber cloth / felt, so that the silicon carbide fiber cloth / felt is completely impregnated with the heat-insulating and ablation-resistant modified resin. Then, the impregnated silicon carbide fiber cloth / felt is placed in an oven and pre-cured at 60-200℃ to obtain a prepreg.

[0025] (c) After cutting the prepreg obtained in step (b) to the size of the mold, place it on the substrate and lay it in the mold layer by layer for molding. The molding temperature is 120-300℃ and the pressure is 0.5-10Mpa, thus obtaining the heat-insulating and ablation-resistant battery pack shell material.

[0026] In a further preferred embodiment, the stirring rate in step (a) is 150-200 rpm and the stirring time is 1-5 h.

[0027] Beneficial effects

[0028] (1) The heat-insulating and ablation-resistant composite material provided by the present invention combines heat-insulating and ablation-resistant modified resin with silicon carbide fiber cloth / felt to achieve integrated heat insulation and ablation resistance. The heat-insulating and ablation-resistant modified resin can foam and expand and inorganically form a foam layer under flame ablation at 1300℃, which can block the flame ablation. The foam layer formed by foaming has high strength and the pores do not collapse after continuous ablation for 30 minutes. At the same time, the present invention uses silicon carbide fiber cloth / felt as a reinforcing material, which can reduce the expansion ratio of the modified resin and enhance the strength of the foam matrix. After the overall ablation for 30 minutes, the sample does not exhibit delamination, cracking, or burn-through. The temperature of the shell back plate is below 300℃, and it has good heat insulation and ablation resistance effects.

[0029] (2) The battery pack shell prepared using the battery pack shell material prepared by the present invention is thin and lightweight, which can effectively reduce the overall weight of electric vehicles and increase their range.

[0030] (3) The preparation process of this invention is short, the equipment requirements are low, the preparation process is simple and easy to achieve mass production, and the lightweight heat-insulating and ablation-resistant battery pack shell prepared meets the needs of new energy batteries. Attached Figure Description

[0031] The accompanying drawings are provided to enhance further understanding of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0032] Figure 1 This is a photograph of the composite material of silicon carbide-free fiber cloth / felt from Comparative Example 1 after ablation at 1300℃ for 30 minutes.

[0033] Figure 2 This is a photograph of the heat-insulating and ablation-resistant composite material of Example 2 after ablation at 1300℃ for 30 minutes.

[0034] Figure 3 This is a photograph of the composite material prepared without foaming agent in the preparation of the heat-insulating and ablation-resistant modified resin of Comparative Example 3 after 30 minutes of ablation. Detailed Implementation

[0035] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0038] Example 1:

[0039] This embodiment provides a heat-insulating and ablation-resistant composite material, including a matrix plate and a silicon carbide fiber-reinforced resin composite material pressed on the matrix plate. The silicon carbide fiber-reinforced resin composite material is obtained by coating both sides of the silicon carbide fiber cloth / felt with heat-insulating and ablation-resistant modified resin and impregnating and curing it with the heat-insulating and ablation-resistant modified resin. The heat-insulating and ablation-resistant modified resin is composed of the following components by weight percentage: 50% bisphenol A type epoxy resin, 7% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 10% phenolic resin, 3% melamine, 15% aluminum hydroxide, and 5% polydimethylsiloxane.

[0040] The method for preparing the heat-insulating and ablation-resistant composite material provided in this embodiment is as follows:

[0041] The above materials are processed through the following steps:

[0042] Step 1:

[0043] Weigh 100g of bisphenol A epoxy resin according to the ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials according to the above ratio, and continue stirring for 1 hour to obtain the modified resin.

[0044] Step Two:

[0045] The prepared modified resin was sprayed evenly on both the upper and lower surfaces of the silicon carbide fiber cloth / felt using a spraying machine, so that the silicon carbide fiber cloth / felt was completely impregnated with the heat-insulating and ablation-resistant modified resin. Then, it was placed in an oven and pre-cured at 100°C to obtain silicon carbide fiber cloth / felt prepreg.

[0046] Step 3:

[0047] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required product size, placed on a base plate and laid in a mold. It was then molded at 180°C and 0.5 MPa using a flatbed press to obtain a 1.5 mm thick heat-insulating and ablation-resistant composite material.

[0048] The prepared heat-insulating and ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the heat-insulating and ablation-resistant composite material was 1300℃. After 30 minutes of ablation, the back temperature of the heat-insulating and ablation-resistant composite material was 218℃. The overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 2.2, and the final ablation state was basically intact.

[0049] Example 2:

[0050] This embodiment provides a heat-insulating and ablation-resistant composite material, which is basically the same as that in Embodiment 1, except that the composition ratio of the heat-insulating and ablation-resistant modified resin is different:

[0051] In this embodiment, the heat-insulating and ablation-resistant modified resin is composed of the following components by weight percentage: 40% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 5% melamine, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0052] The above materials are processed through the following steps:

[0053] Step 1:

[0054] Weigh 80g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0055] The prepared modified resin was sprayed evenly on both the upper and lower surfaces of the silicon carbide fiber cloth / felt using a spraying machine, so that the silicon carbide fiber cloth / felt was completely impregnated with the heat-insulating and ablation-resistant modified resin. Then, it was placed in an oven and pre-cured at 100°C to obtain the prepreg.

[0056] Step 3:

[0057] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required product size, placed on a base plate and layered into a mold. It was then molded using a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a 1.5 mm thick heat-insulating and ablation-resistant composite material.

[0058] The prepared heat-insulating and ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The surface temperature of the heat-insulating and ablation-resistant composite material was 1300℃. After 30 minutes of ablation, as follows... Figure 2 As shown, the backplate temperature of the heat-insulating and ablation-resistant composite material was 156℃, the overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 3.5, and the final ablation state was basically intact.

[0059] The foam structure reinforced with fiber matrix has high strength. After ablation at 1300℃, the ablated surface remains intact, the pores do not rupture, and the shape is well preserved, thus achieving a good heat insulation effect.

[0060] Example 3:

[0061] This embodiment provides a heat-insulating and ablation-resistant composite material, which is basically the same as that in Embodiment 1, except that the composition ratio of the heat-insulating and ablation-resistant modified resin is different:

[0062] In this embodiment, the heat-insulating and ablation-resistant modified resin is composed of the following components by weight percentage: 35% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 10% phenolic resin, 5% melamine, 20% aluminum hydroxide, and 15% polydimethylsiloxane.

[0063] The above materials are processed through the following steps:

[0064] Step 1:

[0065] Weigh 75g of epoxy resin according to the ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials mentioned above, and continue stirring for 1 hour to obtain the modified resin.

[0066] Step Two:

[0067] The prepared modified resin was sprayed evenly onto silicon carbide fiber felt using a spraying machine, and then placed in an oven for pre-curing at 100°C to obtain prepreg.

[0068] Step 3:

[0069] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required product size, placed on a base plate and layered into a mold. It was then molded using a flatbed press at 150°C and a pressure of not less than 0.5 MPa to obtain a 1.5 mm thick heat-insulating and ablation-resistant composite material.

[0070] The prepared heat-insulating and ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the heat-insulating and ablation-resistant composite material was 1300℃. After 30 minutes of ablation, the back temperature of the heat-insulating and ablation-resistant composite material was 232℃. The overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 4.5. In the end, only 2 / 5 of the foamed structure was burned through.

[0071] Example 4:

[0072] This embodiment provides a heat-insulating and ablation-resistant composite material, which is basically the same as that in Embodiment 2, except that the reinforcement is silicon carbide fiber cloth.

[0073] The heat-insulating and ablation-resistant modified resin is composed of the following components by weight percentage: 40% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 5% melamine, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0074] The above materials are processed through the following steps:

[0075] Step 1:

[0076] Weigh 80g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, start stirring at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0077] The prepared modified resin was sprayed evenly onto silicon carbide fiber cloth using a spraying machine, and then placed in an oven for pre-curing at 100°C to obtain prepreg.

[0078] Step 3:

[0079] Silicon carbide fiber cloth prepreg is cut to the required size of the product, placed on a base plate and laid in a mold. It is then molded using a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a 1.5 mm thick heat-insulating and ablation-resistant composite material.

[0080] The prepared heat-insulating and ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the heat-insulating and ablation-resistant composite material was 1300℃. After 30 minutes of ablation, the back temperature of the heat-insulating and ablation-resistant composite material was 282℃. The overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 1.5, and the final ablation state was basically intact.

[0081] Example 5:

[0082] This embodiment provides a heat-insulating and ablation-resistant composite material, which is basically the same as that in Embodiment 2, except that the reinforcement is silicon carbide fiber felt.

[0083] The heat-insulating and ablation-resistant modified resin is composed of the following components by weight percentage: 40% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 5% melamine, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0084] The above materials are processed through the following steps:

[0085] Step 1:

[0086] Weigh 80g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, start stirring at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0087] The prepared modified resin was sprayed onto silicon carbide fiber felt using a spraying machine, and then placed in an oven for pre-curing at 100°C to obtain prepreg.

[0088] Step 3:

[0089] Silicon carbide fiber felt prepreg is cut to the required size of the product, placed on a base plate and laid in a mold. It is then molded using a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a 1.5 mm thick heat-insulating and ablation-resistant composite material.

[0090] The prepared heat-insulating and ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the heat-insulating and ablation-resistant composite material was 1300℃. After 30 minutes of ablation, the back plate temperature of the heat-insulating and ablation-resistant composite material was 274℃. The overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 4.8. Finally, 3 / 5 of the foamed structure was burned through, and the fiber felt skeleton was exposed in many places, but the matrix of the heat-insulating and ablation-resistant composite material was intact.

[0091] Comparative Example 1:

[0092] This comparative example provides a composite material that is basically the same as that in Example 2, except that the heat-insulating and ablation-resistant modified resin is directly sprayed onto the substrate in this comparative example, and the composite material prepared in this comparative example does not contain silicon carbide fiber cloth / felt.

[0093] In this comparative example, the composition of the heat-insulating and ablation-resistant modified resin is the same as in Example 2, consisting of the following components by weight percentage: 40% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 5% melamine, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0094] The above materials are processed through the following steps:

[0095] Step 1:

[0096] Weigh 80g of epoxy resin according to the ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the ratio, and continue stirring for 1 hour to obtain the modified resin.

[0097] Step Two:

[0098] The prepared modified resin was sprayed onto the substrate using a sprayer, and then molded on a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a composite material with a thickness of 1.5 mm.

[0099] The prepared composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The temperature of the front side of the shell was 1300℃. After 30 minutes of ablation, if... Figure 1 As shown, the backing temperature of the tested composite material was 358℃, and the overall foaming ratio of the heat-insulating and ablation-resistant modified resin was 6.2. The foamed structure was burned through, and the sample had no strength after ablation. This comparative example did not have silicon carbide fiber cloth / felt reinforcement, and the foamed structure was fragile. After ablation at 1300℃ for 1 minute, the pores were gradually burned through, resulting in poor heat insulation performance.

[0100] Comparative Example 2:

[0101] This comparative example provides a composite material whose structure is basically the same as that of Example 1. The difference is that the composition of the modified resin is not within the scope of protection. The modified resin in this comparative example is composed of the following components by weight percentage: 15% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 5% melamine, 30% aluminum hydroxide, and 20% polydimethylsiloxane.

[0102] The above materials are processed through the following steps:

[0103] Step 1:

[0104] Weigh 30g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, start stirring at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0105] The prepared modified resin was sprayed evenly onto silicon carbide fiber cloth / felt using a spraying machine, and then placed in an oven for pre-curing at 100°C to obtain prepreg.

[0106] Step 3:

[0107] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required size of the product, placed on a substrate and laid in a mold. It was then molded using a flatbed press at 150°C and a pressure of not less than 0.5 MPa to obtain a composite material with a thickness of 1.5 mm.

[0108] The prepared composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the composite material was 1300℃. After 30 minutes of ablation, the back temperature of the composite material was 308℃. The overall foaming ratio of the heat insulation and ablation resistant modified resin was 5.5. Finally, 2 / 3 of the foamed structure was burned through.

[0109] Comparative Example 3:

[0110] This embodiment provides a composite material that is basically the same as that in Embodiment 2, except that the heat-insulating and ablation-resistant modified resin of the present invention is not used.

[0111] In this comparative example, the modified resin is composed of the following components by weight percentage (excluding foaming agent): 40% bisphenol A epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 15% phenolic resin, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0112] The above materials are processed through the following steps:

[0113] Step 1:

[0114] Weigh 80g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0115] The prepared modified resin was sprayed evenly on both the upper and lower surfaces of the silicon carbide fiber cloth / felt using a spraying machine, so that the silicon carbide fiber cloth / felt was completely impregnated with the modified resin. Then, it was placed in an oven and pre-cured at 100°C to obtain the prepreg.

[0116] Step 3:

[0117] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required product size, placed on a substrate and layered into a mold. It was then molded using a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a composite material with a thickness of 1.5 mm.

[0118] The prepared composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The surface temperature of the composite material was 1300℃. After 30 minutes of ablation, as follows... Figure 3As shown; the backplate temperature of the composite material was 370℃, which is higher than 300℃, resulting in poor thermal insulation. This comparative example failed to generate a thermally insulating and ablation-resistant modified resin and failed to form a foamed matrix. In this comparative example, the system without foaming agent failed to foam during the ablation test. Although the matrix also exhibited good ablation resistance, the thermal insulation effect was poor, and the backplate temperature was high. Comparative Example 4:

[0119] This comparative example provides an ablation-resistant composite material, which is basically the same as Example 2, except that the heat-insulating and ablation-resistant modified resin of the present invention is not used.

[0120] In this embodiment, the modified resin is composed of the following components by weight percentage (excluding carbon-forming agents): 40% bisphenol A type epoxy resin, 5% tetraethylenepentamine, 10% ammonium dihydrogen phosphate, 5% melamine, 20% aluminum hydroxide, and 5% polydimethylsiloxane.

[0121] The above materials are processed through the following steps:

[0122] Step 1:

[0123] Weigh 80g of bisphenol A epoxy resin according to the specified ratio, pour it into a mixing container, turn on the stirrer at a speed of 150-200 rpm, gradually add the other materials mentioned above according to the specified ratio, and continue stirring for 1 hour to obtain the modified resin; Step 2:

[0124] The prepared modified resin was sprayed evenly on both the upper and lower surfaces of the silicon carbide fiber cloth / felt using a spraying machine, so that the silicon carbide fiber cloth / felt was completely impregnated with the modified resin. Then, it was placed in an oven and pre-cured at 100°C to obtain the prepreg.

[0125] Step 3:

[0126] Silicon carbide fiber cloth / felt prepreg with a volume ratio of 2 / 3 to 2 / 3 was cut into the required size of the product, placed on a base plate and laid in a mold. It was then molded using a flatbed press at 200°C and a pressure of not less than 0.5 MPa to obtain a 1.5 mm thick ablation-resistant composite material.

[0127] The prepared ablation-resistant composite material was tested by continuous ablation with a handheld spray gun for 30 minutes. The front temperature of the ablation-resistant composite material was 1300℃. After 30 minutes of ablation, the back temperature of the ablation-resistant composite material was 382℃. The foaming ratio of the modified resin was 3.8, the strength of the foam matrix was low, and 4 / 5 of the structure was burned through. The back temperature of the comparative example was higher than 300℃, and the heat insulation effect was poor. This comparative example failed to generate a heat-insulating and ablation-resistant modified resin and could not achieve the inorganicization of the foam.

[0128]

Claims

1. A heat-insulating and ablation-resistant composite material, characterized in that, The invention comprises a matrix plate and a silicon carbide fiber reinforced resin composite material pressed onto the matrix plate. The silicon carbide fiber reinforced resin composite material is obtained by coating both sides of a silicon carbide fiber cloth / felt with a heat-insulating and ablation-resistant modified resin, and then completely impregnating and curing it with the heat-insulating and ablation-resistant modified resin. The heat-insulating and ablation-resistant modified resin is prepared by mixing 20%-60% by weight of epoxy resin, 2%-10% by weight of curing agent, 5%-15% by weight of catalyst, 10%-15% by weight of charring agent, 3%-5% by weight of foaming agent, 15%-20% by weight of flame retardant, and 5%-15% by weight of additives. The volume ratio of silicon carbide fiber cloth to silicon carbide fiber felt in the silicon carbide fiber cloth / felt is 1:5 to 5:

1.

2. The heat-insulating and ablation-resistant composite material according to claim 1, characterized in that, The silicon carbide fiber cloth is a second-generation silicon carbide fiber cloth; the silicon carbide fiber felt is a second-generation silicon carbide fiber felt.

3. The heat-insulating and ablation-resistant composite material according to claim 1, characterized in that, The epoxy resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, organosilicon modified epoxy resin, and hydrogenated bisphenol A type epoxy resin. The curing agent is one of tetraethylenepentamine, diethylenetriamine, polyethyleneimine, and polyamide; The catalyst is one of ammonium dihydrogen phosphate, borate, and organic phosphate ester; The carbon-forming agent is one or more of epoxy resin, phenolic resin, aldehyde-ketone resin, starch, and cellulose; The foaming agent is one of melamine, urea, and azodicarbonamide; The flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, aluminum oxide, antimony trioxide, and zinc oxide; The additive is one or more of silicone oil, alkyl-modified organosiloxane, and polyether polyester-modified organosiloxane.

4. The heat-insulating and ablation-resistant composite material according to claim 1, characterized in that, The substrate is one of aluminum plate, steel plate, or fiber-reinforced resin-based composite board.

5. A method for preparing a heat-insulating and ablation-resistant composite material as described in any one of claims 1-4, comprising the following steps: (a) Prepare the components according to the formula of the heat-insulating and ablation-resistant modified resin, stir and mix them evenly, and set aside for later use; (b) The heat-insulating and ablation-resistant modified resin obtained in step (a) is evenly sprayed onto the upper and lower surfaces of the silicon carbide fiber cloth / felt, so that the silicon carbide fiber cloth / felt is completely impregnated with the heat-insulating and ablation-resistant modified resin. Then, the impregnated silicon carbide fiber cloth / felt is placed in an oven and pre-cured at 60-200℃ to obtain a prepreg. (c) After cutting the prepreg obtained in step (b) to the size of the mold, place it on the substrate and lay it together in the mold for molding. The molding temperature is 120-300℃ and the pressure is 0.5-10Mpa, thus obtaining the heat-insulating and ablation-resistant composite material.

6. The method for preparing a heat-insulating and ablation-resistant composite material according to claim 5, characterized in that, The stirring rate in step (a) is 150-200 rpm, and the stirring time is 1-5 h.

7. The application of a heat-insulating and ablation-resistant composite material as described in any one of claims 1-4, or a heat-insulating and ablation-resistant composite material prepared by the preparation method of a heat-insulating and ablation-resistant composite material as described in any one of claims 5-6, in the manufacture of a battery pack casing.

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