Composite material, preparation method thereof and battery upper cover plate

Abstract

The invention discloses a composite material, a preparation method thereof and a battery upper cover plate, the composite material comprises continuous fiber reinforced nylon, or the composite material comprises continuous fiber reinforced nylon and long fiber reinforced nylon. The composite material disclosed by the invention not only can have high strength, high rigidity and excellent corrosion resistance and environmental influence resistance, but also can have light weight, high toughness and good forming performance.

Description

Technical Field

[0001] The invention belongs to the field of composite materials, and in particular relates to a composite material and a preparation method thereof, and a battery upper cover plate. Background Art

[0002] New energy vehicle power batteries and energy storage batteries are widely used. Battery assembly packaging is mostly made of aluminum alloy materials, including the upper cover of the battery pack. In the prior art, most of the upper covers of battery packs are made of aluminum alloy materials, with many processes and complex assembly. A small number of them are made of fiberglass materials, which have problems with environmental protection and recycling. For lightweight considerations, a type of battery upper cover made of thermosetting composite materials has appeared on the market. However, this type of material is a thermosetting material and has the problem of being non-recyclable. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a composite material, a preparation method thereof and a battery upper cover plate.

[0004] The invention provides a composite material, which comprises: continuous fiber reinforced nylon, or the composite material comprises: continuous fiber reinforced nylon and long fiber reinforced nylon.

[0005] The composite material of the present invention includes continuous fiber reinforced nylon, which can significantly improve the strength and stiffness of the composite material and show good mechanical properties; furthermore, the continuous fiber reinforced nylon has the characteristics of light weight and high rigidity; in addition, the continuous fiber reinforced nylon can significantly improve the corrosion resistance and environmental resistance of the composite material.

[0006] The composite material of the present invention includes continuous fiber reinforced nylon and long fiber reinforced nylon. On the one hand, continuous fiber reinforced nylon can significantly improve the strength and stiffness of the composite material, showing good mechanical properties; furthermore, continuous fiber reinforced nylon has the characteristics of light weight and high rigidity; in addition, continuous fiber reinforced nylon can significantly improve the corrosion resistance and environmental resistance of the composite material. On the other hand, the unique non-oriented fiber network structure of the long fiber can maintain high mechanical properties under high and low temperature conditions and in high and low temperature high frequency alternating environments, and the long fiber length distribution is better, which can significantly improve the mechanical properties of the composite material, and can significantly improve the strength and toughness of the composite material; furthermore, long fiber reinforced nylon has good fatigue performance, can effectively delay the fatigue damage of the composite material, and improve the reliability and durability of the composite material; furthermore, long fiber reinforced nylon also has good molding performance. In the manufacturing process, the material often needs to be molded. Due to its good molding performance, long fiber reinforced nylon can realize the manufacturing of complex shapes and meet the needs of different engineering structures. The synergistic effect of the above-mentioned continuous fiber reinforced nylon and long fiber reinforced nylon can not only significantly improve the strength, stiffness, corrosion resistance and environmental resistance of the composite material, but also enable the composite material to have the technical effects of lightweight, high toughness and good molding performance.

[0007] Preferably, the composite material comprises: continuous fiber reinforced nylon and long fiber reinforced nylon, and the mass ratio of the continuous fiber reinforced nylon to the long fiber reinforced nylon is (2:8) to (8:2).

[0008] The composite material described in this scheme includes: continuous fiber reinforced nylon and long fiber reinforced nylon, and the mass ratio of the continuous fiber reinforced nylon to the long fiber reinforced nylon is (2:8) to (8:2). The mass ratio of the continuous fiber reinforced nylon to the long fiber reinforced nylon is within this range, which can further improve the mechanical properties of the composite material and further improve the corrosion resistance of the composite material.

[0009] Preferably, the continuous fibers in the continuous fiber reinforced nylon include at least one of continuous glass fibers, continuous carbon fibers, and continuous basalt fibers; and the long fibers in the long fiber reinforced nylon include at least one of long glass fibers, long carbon fibers, and long basalt fibers.

[0010] Preferably, the length of the long glass fiber is 10-15 mm, the length of the long carbon fiber is 8-10 mm, and the length of the long basalt fiber is 10-12 mm.

[0011] Preferably, the mass ratio of continuous fibers to nylon in the continuous fiber reinforced nylon is (50:50) to (80:20); and the mass ratio of long fibers to nylon in the long fiber reinforced nylon is (20:80) to (50:50).

[0012] Preferably, the mass ratio of continuous fibers to nylon in the continuous fiber reinforced nylon is 50:50; and the mass ratio of long fibers to nylon in the long fiber reinforced nylon is 30:70.

[0013] Preferably, the nylon in the continuous fiber reinforced nylon comprises polycaprolactam.

[0014] The nylon in the continuous fiber reinforced nylon described in this solution includes polycaprolactam. The continuous fiber reinforced polycaprolactam has good comprehensive properties, and its heat deformation temperature, strength and modulus are significantly improved.

[0015] Preferably, the continuous fibers include surface-treated continuous fibers, and the surface treatment agent used for the surface treatment includes at least one of a film-forming agent, a lubricant, and a coupling agent.

[0016] The continuous fiber described in this scheme includes a continuous fiber after surface treatment, and the surface treatment agent used for the surface treatment includes at least one of a film-forming agent, a lubricant, and a coupling agent, wherein the film-forming agent is a resin film of a polymer material formed on the surface of the continuous glass fiber monofilament to coat the continuous glass fiber yarn, facilitate the bundling of the continuous glass fiber, enhance the bundling of the synthetic fiber, and thus improve its fineness and strength; the lubricant provides a lubricating effect, reduces friction and reduces hairiness in the early and late processing; the coupling agent modifies the fiber surface, connects the inorganic fiber surface to the organic material, improves the interface performance of the fiber surface, and then improves its tensile, bending, and impact comprehensive performance. The surface-treated continuous fiber can be beneficial to the processing and preparation of continuous fiber reinforced nylon to form high-strength continuous fiber reinforced nylon.

[0017] Preferably, in terms of mass fraction, the surface treatment agent comprises 3%-5% of film-forming agent, 0.5%-1.0% of lubricant, and 0.1%-0.8% of coupling agent.

[0018] Preferably, the film-forming agent includes a polyurethane film-forming agent, and the polyurethane film-forming agent includes a polyurethane with a number average molecular weight of 400-1000 and a polyurethane with a number average molecular weight of 2000-3000, and the mass ratio of the polyurethane with a number average molecular weight of 400-1000 and the polyurethane with a number average molecular weight of 2000-3000 is (3:7) to (7:3).

[0019] The mass ratio of the polyurethane with a number average molecular weight of 400 to 1000 and the polyurethane with a number average molecular weight of 2000 to 3000 described in this scheme is (3:7) to (7:3). The mass ratio of these two high and low molecular weight polyurethane film-forming agents is within this range, which can make the continuous glass fiber have a suitable degree of softness and hardness, which is beneficial to bundling, weaving, and fabric preforming.

[0020] Preferably, the lubricant is a non-ionic lubricant.

[0021] Preferably, the lubricant is at least one of a mineral oil lubricant and a silicone lubricant.

[0022] Preferably, the thermal decomposition temperature of the coupling agent is ≥300° C., and the coupling agent is a silane coupling agent containing terminal amino groups.

[0023] The thermal decomposition temperature of the coupling agent described in this scheme is ≥300°C, which is beneficial to reducing the thermal degradation of the coupling agent during the subsequent processing and heating process; the coupling agent is a silane coupling agent containing terminal amino groups, which can reduce the temperature sensitivity of the coupling agent, improve thermal stability, and facilitate subsequent reaction molding.

[0024] Preferably, the composite material further comprises a flame retardant.

[0025] The present invention provides a method for preparing the composite material, the method comprising the following steps:

[0026] S1. Place the continuous fiber into a mold, add nylon 1 monomer, a catalyst and an activator, and heat the reaction to obtain continuous fiber reinforced nylon;

[0027] S2. Compounding nylon 2 and long fibers to obtain long fiber reinforced nylon;

[0028] S3. Compounding the continuous fiber reinforced nylon in step S1 and the long fiber reinforced nylon in step S2 to obtain the composite material.

[0029] The present invention adopts an in-situ polymerization method when preparing continuous fiber reinforced nylon, which is equivalent to completing the production of continuous fiber reinforced nylon in one step, can reduce the process and cost, and at the same time ensure the strength and quality stability of the continuous fiber reinforced nylon.

[0030] Preferably, in step S1, placing the continuous fiber into the mold includes preheating the continuous fiber and then placing it into the mold, and the preheating temperature is 120-200°C.

[0031] Preferably, in step S1, the heating is heating to 160-200°C.

[0032] Preferably, the nylon 1 monomer includes caprolactam, and the nylon 2 includes at least one of PA6YH800 and PA66EPR27.

[0033] The present invention also provides a battery upper cover plate, wherein the battery upper cover plate comprises the composite material. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only embodiments of a part of the present invention, rather than all embodiments.

[0035] The following continuous glass fibers are all surface treated as follows:

[0036] Calculated by mass fraction, the surface treatment liquid components are: 3.5% polyurethane film-forming agent, wherein the mass ratio of the polyurethane film-forming agent with a number average molecular weight of 800 to the polyurethane film-forming agent with a number average molecular weight of 2500 is 1:1; 0.56% lubricant paraffin, 0.2% silane coupling agent KH550, 0.2% acetic acid, and the rest is an aqueous solution adjusted with acetic acid to pH = 5-6.

[0037] Preparation of surface treatment liquid: prepare deionized water, add acetic acid, adjust the pH to 5-6, obtain 95.54kg aqueous solution, add 0.2kg silane coupling agent KH550, stir, heat to 50°C, after the coupling agent is completely hydrolyzed, add 0.56kg lubricant paraffin, 3.5kg polyurethane film-forming agent and 0.2kg acetic acid, stir evenly, adjust the pH to 6-7, and set aside.

[0038] Continuous glass fiber cloth processing method: Place the surface treatment liquid in a square container, immerse the continuous glass fiber directly in the treatment liquid, take out the immersed continuous glass fiber, and then dry the excess water for standby use.

[0039] The following continuous carbon fibers are all surface treated as follows:

[0040] Calculated by mass fraction, the surface treatment liquid components are: 4% polyurethane film-forming agent, wherein the mass ratio of the polyurethane film-forming agent with a number average molecular weight of 800 to the polyurethane film-forming agent with a number average molecular weight of 2500 is 1:1; 0.56% lubricant paraffin, 0.3% silane coupling agent KH550, 0.2% acetic acid, and the rest is an aqueous solution adjusted with acetic acid to pH = 5-6.

[0041] Preparation of surface treatment liquid: prepare deionized water, add acetic acid, adjust the pH to 5-6, obtain 94.94kg aqueous solution, add 0.3kg silane coupling agent KH550, stir, heat to 50°C, after the coupling agent is completely hydrolyzed, add 0.56kg lubricant paraffin, 4kg polyurethane film and 0.2kg acetic acid, stir evenly, adjust the pH to 6-7, and set aside.

[0042] Continuous carbon fiber treatment method: place the surface treatment liquid in a square container, immerse the continuous carbon fiber directly in the treatment liquid, take out the immersed continuous carbon fiber, and then dry the excess water for standby use.

[0043] The following continuous basalt fibers are all surface treated as follows:

[0044] Treatment liquid components: 3.5% polyurethane film-forming agent, wherein the mass ratio of the polyurethane film-forming agent with a number average molecular weight of 800 to the polyurethane film-forming agent with a number average molecular weight of 2500 is 1:1; 0.56% lubricant paraffin, 0.2% silane coupling agent KH550, 0.2% acetic acid, and the rest is an aqueous solution adjusted to pH = 5-6 with acetic acid, 95.54% of which is deionized water.

[0045] Preparation of surface treatment liquid: prepare deionized water, add acetic acid, adjust the pH to 5-6, obtain 95.54kg aqueous solution, add 0.2kg silane coupling agent KH550, stir, heat to 50°C, after the coupling agent is completely hydrolyzed, add 0.56kg lubricant paraffin, 3.5kg polyurethane film and 0.2kg acetic acid, stir evenly, adjust the pH to 6-7, and set aside.

[0046] Continuous basalt fiber treatment method: place the surface treatment liquid in a square container, immerse the continuous basalt fiber directly in the treatment liquid, take out the immersed continuous basalt fiber, and then dry the excess water for standby use.

[0047] Example 1

[0048] S1. Preheat 1200g of continuous glass fiber after surface treatment by the above method, the preheating temperature is 160°C, and a preheated continuous fiber preform is obtained. Then the preheated continuous fiber preform is placed in an in-situ polymerization mold, the mold temperature is 160°C, and the mold is closed. By injecting 600g of a mixture of caprolactam and diisocyanate (wherein caprolactam is 595g and diisocyanate is 5g), 600g of a mixture of caprolactam and sodium caprolactam (wherein caprolactam is 599.4g and sodium caprolactam is 0.6g), and 200g of phosphorus nitrogen flame retardant into the mold, mixed and injected, the reaction is completed in the mold for 0.1h, and continuous glass fiber reinforced nylon is obtained.

[0049] S2.1750g nylon resin PA6YH800 and 480g phosphorus nitrogen flame retardant are extruded into the second-stage extruder through the first-stage extruder, and the second-stage extruder is compounded with 750g long glass fiber T435R, and the long glass fiber reinforced nylon is extruded through the second-stage die.

[0050] S3. The 1000g continuous glass fiber reinforced nylon prepared in the above step S1 is heated to 260°C by baking and then transferred to the battery cover mold, and then the 1000g long glass fiber reinforced nylon prepared in step S2 is simultaneously transferred to the mold, the mold is closed, and compression molding is performed to obtain the battery cover.

[0051] Example 2

[0052] S1. Preheat 1200g of continuous carbon fiber after surface treatment by the above method, preheating temperature 160°C, to obtain a preheated continuous fiber preform. Then place the preheated continuous fiber preform in an in-situ polymerization mold, the mold temperature is 160°C, and the mold is closed. By injecting 600g of a mixture of caprolactam and diisocyanate (wherein caprolactam is 595g and diisocyanate is 5g), 600g of a mixture of caprolactam and sodium caprolactam (wherein caprolactam is 599.4g and sodium caprolactam is 0.6g), 200g of phosphorus nitrogen flame retardant into the mold, mixed injection, complete the reaction in the mold for 0.1h, to obtain continuous carbon fiber reinforced nylon.

[0053] S2.1750g nylon resin PA66EPR27 and 480g phosphorus nitrogen flame retardant are extruded into the second-stage extruder through the first-stage extruder, and the second-stage extruder is compounded with 750g long carbon fiber, which is extruded through the second-stage die to obtain long carbon fiber reinforced nylon.

[0054] S3. The 500g continuous carbon fiber reinforced nylon prepared in the above step S1 is transferred to the battery cover mold after being heated to 250°C by baking, and then the 2000g long carbon fiber reinforced nylon prepared in step S2 is simultaneously transferred to the mold, the mold is closed, and compression molding is performed to obtain the battery cover.

[0055] Example 3

[0056] S1. 1200g of continuous basalt fiber is surface treated by the above method and then preheated at 160°C to obtain a preheated continuous fiber preform. The preheated continuous fiber preform is then placed in an in-situ polymerization mold at a mold temperature of 160°C and the mold is closed. A mixture of 600g of caprolactam and diisocyanate (595g of caprolactam and 5g of diisocyanate), 600g of caprolactam and sodium caprolactam (599.4g of caprolactam and 0.6g of sodium caprolactam) and 200g of phosphorus-nitrogen flame retardant are injected into the mold, mixed and injected, and the reaction is completed in the mold for 0.1h to obtain continuous basalt fiber reinforced nylon.

[0057] S2.1750g nylon resin PA6YH800 and 480g phosphorus-nitrogen flame retardant are extruded into the second-stage extruder through the first-stage extruder, and the second-stage extruder is compounded with 750g long basalt fiber, and the long basalt fiber reinforced nylon is obtained by extruding through the second-stage die.

[0058] S3. The 1000 g continuous basalt fiber reinforced nylon prepared in the above step S1 is transferred to the battery cover mold after being heated to 260°C by baking, and then the 250 g long basalt fiber reinforced nylon prepared in step S2 is simultaneously transferred to the mold, the mold is closed, and compression molding is performed to obtain the battery cover.

[0059] Example 4

[0060] S1. Inject 600g of a mixture of caprolactam and diisocyanate (595g of caprolactam and 5g of diisocyanate), 600g of a mixture of caprolactam and sodium caprolactam (599.4g of caprolactam and 0.6g of sodium caprolactam), and 200g of a phosphorus-nitrogen flame retardant into a mold, mix and inject, and complete the reaction in the mold for 0.1h to obtain polycaprolactam.

[0061] S2. The polycaprolactam prepared in step S1 is extruded into a second-stage extruder through a first-stage extruder, and the second-stage extruder is compounded with 1200 g of continuous glass fiber surface-treated by the above method, and extruded through a second-stage die to obtain continuous glass fiber reinforced nylon.

[0062] S2.1750g nylon resin PA6YH800 and 480g phosphorus nitrogen flame retardant are extruded into the second-stage extruder through the first-stage extruder, and the second-stage extruder is compounded with 750g long glass fiber T435R, and the long glass fiber reinforced nylon is extruded through the second-stage die.

[0063] S3. The 1000g continuous glass fiber reinforced nylon prepared in the above step S1 is heated to 260°C by baking and then transferred to the battery cover mold, and then the 1000g long glass fiber reinforced nylon prepared in step S2 is simultaneously transferred to the mold, the mold is closed, and compression molding is performed to obtain the battery cover.

[0064] Example 5

[0065] In this embodiment, step S1 uses continuous glass fibers that have not been surface treated by the above method. The rest is the same as in embodiment 1.

[0066] Example 6

[0067] S1. Preheat 1200g of continuous glass fiber after surface treatment by the above method, the preheating temperature is 160°C, and a preheated continuous fiber preform is obtained. Then the preheated continuous fiber preform is placed in an in-situ polymerization mold, the mold temperature is 160°C, and the mold is closed. By injecting 600g of a mixture of caprolactam and diisocyanate (wherein caprolactam is 595g and diisocyanate is 5g), 600g of a mixture of caprolactam and sodium caprolactam (wherein caprolactam is 599.4g and sodium caprolactam is 0.6g), and 200g of phosphorus nitrogen flame retardant into the mold, mixed injection, the reaction is completed in the mold for 0.1h, and continuous glass fiber reinforced nylon is obtained. The continuous fiber reinforced nylon is transferred to a pressing mold to press out the battery cover.

[0068] Example 7

[0069] In step S3 of this comparative example, the mass of the continuous fiber reinforced nylon used is 200 g, and the mass of the long fiber reinforced nylon used is 1600 g. The rest is the same as in Example 1.

[0070] Example 8

[0071] In step S3 of this comparative example, the mass of the continuous fiber reinforced nylon used is 1600 g, and the mass of the long fiber reinforced nylon used is 200 g. The rest is the same as in Example 1.

[0072] Comparative Example 1

[0073] S2. 1750g nylon resin PA6YH800 and 480g phosphorus nitrogen flame retardant are extruded through the first-stage extruder to the second-stage extruder, and the second-stage extruder is compounded with 750g long glass fiber T435R, and extruded through the second-stage die to obtain long glass fiber reinforced nylon. The long glass fiber reinforced nylon is transferred to the pressing mold to press out the battery cover.

[0074] Performance Testing

[0075] The performance of the battery top covers prepared in the above embodiments and comparative examples are tested and compared.

[0076] Corrosion resistance: The test sample was placed in a sealed container with an ambient temperature of 80°C and a hydrochloric acid solution concentration of 10% vol and immersed for 30 days, and then the tensile strength was tested.

[0077] After testing, the test performance parameters of the battery top covers prepared in the above embodiments and comparative examples are obtained, as shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] It can be seen from Table 1 that the battery covers prepared in Examples 1 to 8 have good performance in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days, while in Comparative Example 1, only long glass fiber reinforced nylon was used to prepare the battery cover, which was inferior to the above Examples 1 to 8 in the above performances. This fully illustrates that the continuous fiber reinforced nylon, or continuous fiber reinforced nylon and long fiber reinforced nylon prepared by the technical solution of the present invention can not only significantly improve the strength, stiffness, corrosion resistance and environmental resistance of the composite material, but also enable the composite material to have the technical effects of lightweight, high toughness and good molding performance.

[0082] Compared with Example 1, Example 4 first prepares polycaprolactam, and then prepares continuous glass fiber reinforced nylon by extrusion compounding, that is, polycaprolactam is not synthesized in situ in the continuous glass fiber to form continuous glass fiber reinforced nylon as in Example 1. It can be seen from the performance data of Examples 1 and 4 that compared with Example 1, Example 4 is slightly inferior in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength, and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days, especially in the interlaminar shear strength of continuous fiber reinforced nylon. This is because Example 4 separately extrudes and mixes polycaprolactam and continuous glass fiber, and compared with the in-situ synthesis in Example 1, the interlaminar shear strength of the continuous fiber reinforced nylon for the battery cover prepared in Example 4 is poor.

[0083] Compared with Example 1, Example 5 does not use the continuous glass fiber surface treated by the above method. It can be seen from the performance data of Example 1 and Example 5 that compared with Example 1, Example 5 is slightly inferior in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength, and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days. This shows that the above-mentioned surface treatment of the continuous glass fiber can further improve the mechanical properties and corrosion resistance of the battery cover.

[0084] Compared with Example 1, Example 6 does not use continuous fiber reinforced nylon alone to prepare the battery cover, and does not use composite long glass fiber reinforced nylon. It can be seen from the performance data of Examples 1 and 6 that, compared with Example 1, Example 6 is slightly inferior in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days, but can also achieve good mechanical properties and corrosion resistance. This fully demonstrates that the battery cover prepared with the continuous fiber reinforced nylon prepared by the present invention also has good mechanical properties and corrosion resistance.

[0085] Compared with Example 1, Example 7 uses more long fiber reinforced nylon in the raw materials for preparing the battery cover. It can be seen from the performance data of Example 1 and Example 7 that although Example 7 has slightly better performance in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days, the tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days decreases significantly. This shows that when long fiber reinforced nylon is more, the corrosion resistance of the prepared battery cover is poor.

[0086] Compared with Example 1, Example 8 uses more continuous fiber reinforced nylon in the raw materials for preparing the battery cover. From the performance data of Example 1 and Example 8, it can be seen that Example 8 is slightly inferior in tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength of continuous fiber reinforced nylon, simply supported beam impact strength and tensile strength after immersion in 10% vol hydrochloric acid at 80°C for 30 days. This indicates that when there is more continuous fiber reinforced nylon, the mechanical properties of the prepared battery cover are poor.

[0087] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A composite material, characterized in that: The composite material comprises: continuous fiber reinforced nylon, or, the composite material comprises: continuous fiber reinforced nylon and long fiber reinforced nylon.

2. The composite material according to claim 1, characterized in that: The composite material comprises: continuous fiber reinforced nylon and long fiber reinforced nylon, and the mass ratio of the continuous fiber reinforced nylon to the long fiber reinforced nylon is (2:8) to (8:2).

3. The composite material according to claim 1, characterized in that: The continuous fibers in the continuous fiber reinforced nylon include at least one of continuous glass fibers, continuous carbon fibers, and continuous basalt fibers; the long fibers in the long fiber reinforced nylon include at least one of long glass fibers, long carbon fibers, and long basalt fibers.

4. The composite material according to claim 1, characterized in that: The mass ratio of continuous fiber to nylon in the continuous fiber reinforced nylon is (50:50) to (80:20); the mass ratio of long fiber to nylon in the long fiber reinforced nylon is (20:80) to (50:50).

5. The composite material according to claim 1, characterized in that: The nylon in the continuous fiber reinforced nylon includes polycaprolactam.

6. The composite material according to claim 1, characterized in that: The continuous fibers include surface-treated continuous fibers, and the surface treatment agent used in the surface treatment includes at least one of a film-forming agent, a lubricant, and a coupling agent.

7. The composite material according to claim 6, characterized in that: The film-forming agent includes a polyurethane film-forming agent, and the polyurethane film-forming agent includes a polyurethane with a number average molecular weight of 400-1000 and a polyurethane with a number average molecular weight of 2000-3000, and the mass ratio of the polyurethane with a number average molecular weight of 400-1000 and the polyurethane with a number average molecular weight of 2000-3000 is (3:7) to (7:3).

8. A method for preparing the composite material according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: S1. Place the continuous fiber into a mold, add nylon 1 monomer, a catalyst and an activator, and heat the reaction to obtain continuous fiber reinforced nylon; S2. Compounding nylon 2 and long fibers to obtain long fiber reinforced nylon; S3. Compounding the continuous fiber reinforced nylon in step S1 and the long fiber reinforced nylon in step S2 to obtain the composite material.

9. The method for preparing the composite material according to claim 8, characterized in that: The nylon 1 monomer includes caprolactam, and the nylon 2 includes at least one of PA6YH800 and PA66EPR27.

10. A battery upper cover, characterized in that: The battery upper cover plate comprises the composite material according to any one of claims 1 to 7.

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