Uhmwpe fiber reinforced epoxy composite battery protection plate and preparation method and application thereof

Abstract

The application discloses a kind of UHMWPE fiber reinforced epoxy composite battery protection plate and preparation method and application, belong to high polymer composite material and battery safety protection technical field.The application is through "plasma surface activation-GA / PEI and its derivative synergistic co-deposition-metal ion secondary coordination crosslinking-epoxy resin impregnation pre-curing-composite layer / metal layer laminating molding" multistage interface enhancement route, solve the problem that UHMWPE fiber surface inertness is big, and weak with epoxy matrix bonding, and easy interlayer peeling under impact.Experimental results show that:O2 plasma treatment 320 s can significantly improve fiber interface reactivity;After continuous modification by GA / PEI and its derivatives and metal ions, the peel strength and bending strength of the composite material are significantly improved;Under the working condition of 300 J drop hammer, the protection plate can remain without penetration failure and improve the energy absorption capacity.The application has clear process window, raw materials are easy to obtain, and has good repeatability, and is suitable for the manufacture of lightweight high-safety protection structure of new energy vehicles and energy storage systems.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle battery safety protection and polymer composite materials technology, specifically to a UHMWPE fiber-reinforced epoxy composite battery protection plate and its preparation method and application. Background Technology

[0002] The power battery pack is usually located at the bottom of the vehicle and is exposed to complex conditions such as gravel impact, bottom scraping and road debris impact for a long time, which poses a risk of local penetration and structural instability.

[0003] UHMWPE fibers possess advantages such as high specific strength, high toughness, and resistance to chemical corrosion, making them an important candidate reinforcing material for battery protection and lightweighting. However, UHMWPE fibers have few polar functional groups and low surface free energy, resulting in insufficient wetting and interfacial bonding with epoxy resin, making them prone to interlaminar delamination under impact or bending loads.

[0004] Existing single-step modification methods typically only improve one aspect of wettability or roughness, making it difficult to simultaneously achieve high adhesion, high toughness, and stable repeatability. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a UHMWPE fiber-reinforced epoxy composite battery protective plate, which solves the problems of weak interfacial bonding, poor impact resistance, and easy delamination after impact.

[0006] To achieve the above objectives, the present invention provides a method for preparing a UHMWPE fiber-reinforced epoxy composite battery protective plate, characterized by comprising the following steps: S1. The UHMWPE fiber fabric is pre-cleaned and dried, and then subjected to plasma surface activation treatment. S2. Placing the plasma-activated fiber in a mixed modified solution prepared by gallic acid (GA) or its derivatives and polyethyleneimine (PEI) or its derivatives in a mass ratio of 1:0.5~1:4, and co-depositing under alkaline conditions, a one-time coated fiber is obtained. S3. Prepare an aqueous solution containing metal ions using water-soluble metal salts, immerse the primary coated fiber in the aqueous solution for secondary coordination crosslinking, and obtain a secondary modified fiber with multi-level interface reinforcement. S4. Impregnate and lay up the secondary modified fiber with the epoxy resin system, pre-cur and hot-press curing within the gel window to obtain the UHMWPE fiber-reinforced epoxy composite battery protective plate.

[0007] As a further preferred technical solution of the present invention, the UHMWPE fiber fabric has a molecular weight of 1 million to 5 million and an areal density of 100 to 300 g / m². And / or, the pre-cleaning and drying steps are specifically as follows: ultrasonically clean the UHMWPE fiber fabric in anhydrous ethanol for 20-40 min, then ultrasonically clean it 2-4 times with deionized water, and dry it at 50-70℃ for 30-120 min. And / or, the plasma surface activation treatment specifically includes: the plasma atmosphere being O2, N2, or a combination thereof; the treatment power being 300-600 W; and the treatment time being 160-640 s, preferably 500 W and 320 s; preferably, step S3 is performed within 10 minutes after step S2 to ensure the timeliness of the plasma treatment.

[0008] As a further preferred embodiment of the present invention, the pH of the co-deposition reaction is 8.5-9.5, the reaction temperature is 25-65 ℃, and the reaction time is 30-120 min; And / or, the mass ratio of gallic acid or its derivatives to polyethyleneimine or its derivatives is 1:0.5 to 1:4; And / or, the gallic acid derivative is selected from one or more of tannic acid or methylated gallic acid, and the polyethyleneimine derivative is selected from one or more of branched polyethyleneimine, linear polyethyleneimine or hydroxyethylated polyethyleneimine.

[0009] As a further preferred embodiment of the present invention, the concentration of the metal ions is 2-8 g / L, and the soaking time for the secondary coordination crosslinking is 6-24 h; And / or, the metal ion is Zn 2+ Fe 3+ Cu 2+ Ca 2+ At least one of them.

[0010] As a further preferred technical solution of the present invention, the epoxy resin system is a blend of bisphenol A type epoxy resins E51 and E20 in a mass ratio of 2:1 to 4:1.

[0011] As a further preferred technical solution of the present invention, a gel point control process is adopted, and pre-curing is performed 25-35 min after blending bisphenol A type epoxy resins E51 and E20. The hot-pressing conditions are 60-130℃, 8-30 MPa, and 40-80 min. The total thickness of the UHMWPE fiber-reinforced epoxy composite battery protective plate is 4-10 mm, preferably 6-8 mm. More preferably, the hot-pressing curing adopts a gradient temperature and pressure curing method.

[0012] As a further preferred embodiment of the present invention, a curing agent, such as m-phenylenediamine, is also added to the epoxy resin system.

[0013] As a further preferred technical solution of the present invention, the mixed modified solution is obtained by mixing gallic acid (GA) or its derivatives with polyethyleneimine (PEI) or its derivatives, and adding NaOH solution and Tris buffer to adjust the pH to 8.5-9.5.

[0014] According to a second aspect of the present invention, the present invention also provides a UHMWPE fiber-reinforced epoxy composite battery protective plate, which is prepared by the above-described preparation method.

[0015] According to a third aspect of the present invention, the present invention also provides an application of UHMWPE fiber-reinforced epoxy composite battery protection plate in the structure related to power batteries and energy storage battery systems, such as in the bottom protection of new energy vehicles, the bottom protection of energy storage battery boxes, and the structure for resisting foreign object impact.

[0016] The beneficial effects of this invention are as follows: This invention addresses the problems of poor interfacial compatibility, weak interlayer bonding, and easy delamination or even failure after impact in existing UHMWPE fibers and epoxy resins. It constructs a multi-stage interfacial reinforcement preparation route: "plasma activation—GA / PEI synergistic co-deposition—metal ion secondary coordination crosslinking—gel window pre-curing / hot pressing curing." Compared with existing methods that only increase surface roughness or perform single-step chemical modification, this invention not only simultaneously improves fiber surface polarity, interfacial wettability, and chemical bonding ability, but also further forms a stable interfacial crosslinking network through metal ion coordination. This significantly improves interfacial load transfer efficiency, resulting in higher peel strength, interlaminar shear strength, flexural strength, and impact energy absorption performance, exhibiting a superior synergistic effect of strength and toughness.

[0017] Meanwhile, the plasma treatment, GA / PEI modification and metal salt coordination processes used in this invention are mild, the raw materials are widely available and relatively low in cost, the process window is clear, and it is easy to implement continuously and control stably, with good repeatability and industrialization feasibility.

[0018] In terms of application effects, the composite battery protection plate prepared by this invention has the advantages of lightweight, high strength and high impact resistance. In the bottom protection of new energy vehicles, the bottom protection of energy storage battery boxes and the structure against foreign object impact, it can effectively reduce the risk of local penetration, cracking and interlayer failure caused by stone impact, bottom scraping and sudden foreign object impact. It is conducive to improving the service safety, structural reliability and service life of battery system. Therefore, it has good engineering application value and promotion prospects. Detailed Implementation

[0019] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0020] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0021] The main raw materials include: UHMWPE fiber fabric (molecular weight of 3 million, areal density of 200). g / m²), epoxy resin E51, epoxy resin E20, curing agent (m-phenylenediamine), gallic acid (GA), tannic acid, methyl gallate, branched PEI (Mw≈10000, CAS:9002-98-6, item number: E107079-500g, brand: Aladdin), linear PEI (Mw≈25000, CAS:26913-06-4, item number: 31217398-250mg, brand: Zunlijia), ethoxylated polyethyleneimine PEI (Mw≈5000, CAS:26658-46-8, item number: P916878-50g, brand: Macklin), ZnSO4·7H2O, FeCl3·6H2O, CuSO4·5H2O, CaCl2·2H2O, ethanol, deionized water.

[0022] The main equipment includes: plasma treatment machine, constant temperature stirring device, vacuum degassing device, flat plate hot press, electronic universal testing machine and drop hammer impact testing machine.

[0023] Example 1 This embodiment provides a method for preparing a multi-level interface-reinforced UHMWPE fiber-reinforced epoxy composite battery protective plate, the specific steps of which are as follows: S1. Fiber Pretreatment and Plasma Activation: The UHMWPE fiber fabric was ultrasonically cleaned with anhydrous ethanol for 30 min, rinsed three times with deionized water, and then activated at 60°C. o Dry at C for 60 min; then perform plasma surface activation treatment on the dried fiber fabric in an O2 atmosphere at a power of 500 W for 320 s.

[0024] S2, First-stage interface co-deposition: Gallic acid (GA) and branched PEI were mixed at a mass ratio of 1:2. The pH of the system was adjusted to 9.0 using NaOH and Tris buffer solution to prepare a mixed modification solution. Then, the temperature of the modification solution was controlled at 45℃, and the activated fiber fabric was immersed in the mixed modification solution for an interface deposition reaction of 60 min to obtain a first-stage coated fiber.

[0025] S3, Second-level interfacial coordination crosslinking: Zinc chloride is used to prepare Zn containing metal ions. 2+The metal salt aqueous solution was prepared, and the metal ion concentration was controlled at 6.0 g / L. The first-coated fiber was immersed in the metal salt aqueous solution for 24 h to allow the metal ions to coordinate with the functional groups on the fiber surface, thereby constructing a second-level interfacial cross-linking structure and obtaining a multi-level interfacial reinforced modified UHMWPE fiber.

[0026] S4. Epoxy System Preparation, Impregnation, Laying, Pre-curing, and Hot-press Curing: The epoxy resin system is prepared by blending bisphenol A type epoxy resins E51 and E20 with the addition of m-phenylenediamine as a curing agent, wherein E51:E20:curing agent = 8:2:3 (mass ratio). After the resin is mixed, it is vacuum degassed for 8-12 minutes, and the gel window is controlled at around 30 minutes. The above-mentioned secondary modified fiber fabric is immersed in the epoxy system and fully impregnated for 30 minutes to ensure that the resin uniformly coats the fiber. The impregnated fiber fabric is laid out according to the designed layup method, and pre-curing is completed within 25-35 minutes after the epoxy resin is mixed. A segmented curing process is adopted: the first stage is 75℃, 10 MPa, 60 minutes, and the second stage is 120℃, 20 MPa, 60 minutes. After cooling and demolding, a multi-level interface-reinforced UHMWPE fiber-reinforced epoxy composite battery protective plate is obtained.

[0027] Examples 2-4 This embodiment sets up three parallel experiments to investigate the effect of different mixed modified liquid preparation ratios. The only difference between this embodiment and Example 1 is that the ratio of GA / branched PEI in step S2 (see Table 1) is different; the other process steps and parameters are completely consistent with Example 1.

[0028] Examples 5-7 Based on the preparation method of Example 1, three sets of parallel experiments were set up to investigate the effects of different metal ions Zn 2+ The effect of concentration. The only difference between this and Example 1 is that in step S3, the metal ion Zn... 2+ The concentrations (see Table 2) are different; the remaining process steps and parameters are completely consistent with those in Example 1.

[0029] Examples 8-10 Based on the preparation method of Example 1, three sets of parallel experiments were set up to investigate the effects of different types of metal ions. The only difference between them and Example 1 is that the types of metal ions in step S3 (see Table 3) are different; the other process steps and parameters are completely consistent with Example 1.

[0030] Examples 11-14 Based on the preparation method of Example 1, three sets of parallel experiments were set up to investigate the effect of mixed modified liquids of different GA / PEI derivative systems. The only difference between them and Example 1 is that the solute components of the mixed modified liquid in step S3 (see Table 4) are different; the other process steps and parameters are completely consistent with Example 1.

[0031] Comparative Example 1: Plasma-free activation As a control experiment for Example 1, the only difference between it and Example 1 is that the plasma surface activation treatment in step S1 is not performed; the remaining process steps (S2~S4) and parameters are completely consistent with those of Example 1.

[0032] Comparative Example 2: Co-deposition of unmodified liquid As a control experiment for Example 1, the only difference between it and Example 1 is that the co-deposition treatment of the mixed modified liquid in step S2 is not performed; the remaining process steps (S1, S3, S4) and parameters are completely consistent with those of Example 1.

[0033] Comparative Example 3: Unbranched PEI As a control experiment for Example 1, the only difference between it and Example 1 is that the branched PEI is omitted in the mixed modified liquid in step S2, and only GA is used; the remaining process steps (S1, S3, S4) and parameters are completely consistent with those of Example 1.

[0034] Comparative Example 4: Metal Ion-Free Coordination Crosslinking As a control experiment for Example 1, the only difference between it and Example 1 is that the metal ion coordination crosslinking treatment in step S3 is not performed; the remaining process steps (S1, S2, S4) and parameters are completely consistent with those of Example 1.

[0035] The performance test results of the UHMWPE fiber-reinforced epoxy composite battery protective panels of Examples 1-14 and Comparative Examples 1-4 are summarized in Tables 1 to 4. Table 1. Effects of different GA / branched PEI content ratios on the properties of modified fibers Table 2 Different Zn 2+ Effect of concentration on the properties of modified fibers Table 3. Effects of different metal ion types on the properties of modified fibers Table 4. Effects of different GA / PEI derivative systems on the properties of modified fibers Note: The data in Tables 1-4 are the average values ​​of samples with n≥5; except for the variable under investigation, the other process parameters remain consistent.

[0036] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a UHMWPE fiber-reinforced epoxy composite battery protective plate, characterized in that, Includes the following steps: S1. The UHMWPE fiber fabric is pre-cleaned and dried, and then subjected to plasma surface activation treatment. S2. Placing the plasma-activated fiber in a mixed modified solution prepared by gallic acid or its derivative and polyethyleneimine or its derivative in a mass ratio of 1:0.5~1:4, and co-depositing under alkaline conditions, a one-time coated fiber is obtained. S3. Prepare an aqueous solution containing metal ions using water-soluble metal salts, immerse the primary coated fiber in the aqueous solution for secondary coordination crosslinking, and obtain a secondary modified fiber with multi-level interface reinforcement. S4. Impregnate and lay up the secondary modified fiber with the epoxy resin system, pre-cur and hot-press curing within the gel window to obtain the UHMWPE fiber-reinforced epoxy composite battery protective plate.

2. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The UHMWPE fiber fabric has a molecular weight of 1 million to 5 million and an areal density of 100 to 300 g / m². And / or, the pre-cleaning and drying steps are specifically as follows: ultrasonically clean the UHMWPE fiber fabric in anhydrous ethanol for 20-40 minutes, then ultrasonically clean it 2-4 times with deionized water, and dry it at 50-70℃ for 30-120 minutes. And / or, the plasma surface activation treatment specifically includes: a plasma atmosphere of at least one of O2 and N2, a treatment power of 300-600 W, and a treatment time of 160-640 s.

3. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The co-deposition reaction was carried out at a pH of 8.5-9.5, a reaction temperature of 25-65℃, and a reaction time of 30-120 min. And / or, the mass ratio of gallic acid or its derivatives to polyethyleneimine or its derivatives is 1:0.5 to 1:4; And / or, the gallic acid derivative is selected from one or more of tannic acid or methylated gallic acid, and the polyethyleneimine derivative is selected from one or more of branched polyethyleneimine, linear polyethyleneimine or hydroxyethylated polyethyleneimine.

4. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The concentration of the metal ions is 2-8 g / L, and the soaking time for the secondary coordination crosslinking is 6-24 h. And / or, the metal ion is Zn 2+ Fe 3+ Cu 2+ Ca 2+ At least one of them.

5. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The epoxy resin system is a blend of bisphenol A type epoxy resin E51 and bisphenol A type epoxy resin E20 in a mass ratio of 2:1 to 4:

1.

6. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 5, characterized in that, After blending bisphenol A type epoxy resin E51 and bisphenol A type epoxy resin E20, pre-curing molding is performed for 25-35 minutes, and the hot pressing conditions are 60-130℃, 8-30 MPa, and 40-80 minutes; the total thickness of the UHMWPE fiber-reinforced epoxy composite battery protective plate is 4-10 mm.

7. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The epoxy resin system also contains a curing agent.

8. The method for preparing the UHMWPE fiber-reinforced epoxy composite battery protective plate according to claim 1, characterized in that, The hot-press curing process employs a gradient temperature and pressure increase curing method.

9. A UHMWPE fiber-reinforced epoxy composite battery protective plate, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the UHMWPE fiber-reinforced epoxy composite battery protective plate as described in claim 9 in power battery systems and energy storage battery systems.

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