Composite elastic gusset and methods of making and using same

Abstract

This invention provides a composite elastic sandwich panel, its preparation method, and its application. The method includes: preparing a nanofiber membrane loaded with nanofillers from a thermoplastic polymer and performing surface modification; preparing a rubber compound sheet and performing surface modification; performing surface modification on a prepreg; laying the surface-modified rubber compound sheet and prepreg according to a predetermined layering structure, and laying the surface-modified nanofiber membrane between adjacent prepregs; and then performing hot-press co-curing, which cures the resin in the prepreg while simultaneously vulcanizing the rubber in the rubber compound sheet, resulting in a composite elastic sandwich panel. This invention, through multiple surface modifications of the nanofiber membrane, prepreg, and rubber compound sheet, combined with a hot-press co-curing process, enables chemical bonding or interpenetrating cross-linking at the interface between the two phases, significantly improving the interfacial bonding strength and flexibility of the sandwich panel, making it suitable for suppressing volume expansion during the charging and discharging process of ultra-high energy density lithium battery packs.

Description

Technical Field

[0001] This invention belongs to the field of composite material structural design and functional application, specifically involving composite elastic plates with both high toughness and high elasticity, their preparation methods, and applications. Background Technology

[0002] With the rapid development of cutting-edge fields such as unmanned equipment and electric vehicles, the demand for high-energy-density storage batteries is becoming increasingly urgent. High-energy-density storage batteries refer to batteries that store a high amount of energy per unit mass or unit volume. High-energy-density lithium metal battery packs are an important way to achieve high-energy-density energy storage systems. However, during cyclic charging and discharging, the deposition and dissolution of lithium metal in the battery pack causes continuous changes in the electrode structure, leading to significant volume expansion and deformation of the battery as a whole, which in turn affects its electrochemical stability, cycle life, and safety.

[0003] Fiber-reinforced resin matrix composite laminates, with their high specific strength and high specific modulus, are being explored for use in constraining battery deformation and maintaining the spatial stability of internal components. This helps avoid problems such as poor contact and broken ion transport paths caused by excessive displacement, and also suppresses lattice distortion and grain breakage of electrode materials, which is of positive significance for extending battery life.

[0004] However, existing fiber-reinforced resin-based composite laminates face significant technical bottlenecks in meeting the long-term, dynamic deformation constraints required by high-energy-density lithium metal batteries. Due to insufficient interfacial bonding strength between the fiber-reinforced phase and the matrix resin phase, uneven stress transmission occurs under actual stress, easily leading to delamination. This not only directly weakens the overall mechanical properties of the laminate, reducing its tensile, compressive, and flexural strengths, making it difficult to adapt to the complex alternating stress environment during battery charging and discharging; but also, during long-term battery operation, delamination leads to a decline in constraint effectiveness, failing to effectively resist internal stress impacts, thereby accelerating battery structural deformation, disrupting the stability of its internal electrochemical system, and ultimately jeopardizing the battery's cycle life and safety reliability.

[0005] Therefore, there is an urgent need to develop a new composite sandwich structure that combines high toughness, high elasticity and excellent interfacial bonding performance to solve the problem of easy delamination in existing fiber-reinforced composite laminates and meet the dual requirements of ultra-high energy density lithium battery packs for effective deformation suppression and long-term structural stability. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, the present invention aims to provide a composite elastic clamping plate, its preparation method, and its applications. This method significantly improves the interfacial bonding performance and toughness of the clamping plate, as well as its overall flexibility, thereby effectively suppressing volume expansion during battery charging and discharging, ensuring the structural stability of the battery pack, extending battery cycle life, and improving its safety in use.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a composite elastic clamping plate, comprising the following steps: S1. Add thermoplastic polymer and nanofiller to solvent, disperse by ultrasonication to prepare nanofiber membrane loaded with nanofiller, and then perform surface modification treatment on nanofiber membrane loaded with nanofiller. S2. Mix rubber with additives and fillers to form a compound, hot press the compound into a sheet, and perform surface modification treatment on the compound sheet. S3. Surface modification treatment of the prepreg; S4. The surface-modified compound rubber sheet obtained in step S2 and the surface-modified prepreg obtained in step S3 are combined and laid according to a preset layup structure, and the surface-modified nanofiber membrane loaded with nanofillers obtained in step S1 is laid between adjacent surface-modified prepregs; the laid-up system is placed in a mold and co-cured by hot pressing. During the co-curing process, the resin in the prepreg is cured, and the rubber in the compound rubber sheet is vulcanized to obtain the composite elastic sandwich panel.

[0008] This invention introduces a surface-modified nanofiber membrane loaded with nanofillers between adjacent prepregs. The surface-modified nanofibers possess a micro-nano-scale uneven structure, significantly improving the surface roughness and surface energy of the fibers. Furthermore, the high specific surface area and active groups of the nanofillers enhance the adhesion between the fibers and the prepreg resin, and combined with the pull-out and bridging energy dissipation mechanism of thermoplastic fibers, multi-scale toughening is achieved. Simultaneously, surface modification treatments (such as plasma, ozone, or ultraviolet light) are applied to both the prepreg and the compounded rubber sheet, promoting chemical bonding between the prepreg resin and the rubber during co-curing. These synergistic effects significantly improve the interlaminar shear strength and interfacial bonding quality of the composite layer, effectively suppressing the defects of traditional fiber-reinforced laminates, such as easy delamination and uneven stress transmission.

[0009] This invention constructs a rigid-flexible composite system by combining surface-modified rubber sheets (rubber layer) with prepreg and nanofiber membranes (composite material layer) in a pre-defined layup structure. The composite material layer provides rigid support with high specific strength and high modulus, effectively constraining volume expansion during battery charging and discharging. The rubber layer endows the sandwich panel with excellent elastic recovery and deformation buffering capabilities, enabling it to adapt to the periodic volume changes of the electrodes and absorb dynamic stress. Compared to purely rigid laminates, the sandwich panel of this invention maintains high flexural strength and modulus while significantly improving maximum flexural displacement (flexibility). Furthermore, by adjusting the layup ratio, fiber type, and rubber material, stiffness and elasticity can be controlled within a wide range to meet the differentiated needs of various application scenarios. This invention employs a hot-press co-curing process, simultaneously completing the curing of the resin in the surface-modified prepreg and the vulcanization of the rubber in the surface-modified rubber sheet within a single thermal cycle. This allows the two phases to interpenetrate and cross-link at the interface, forming a dense and defect-free integral structure. This process avoids the weak bonding interface problem caused by traditional step-by-step molding (curing / vulcanization before bonding), significantly enhancing the interfacial bonding strength between the rubber layer and the composite material layer and suppressing interlayer delamination. The surface modification treatment of the compound rubber sheet in step S2 and the surface modification treatment of the prepreg in step S3 constitute a "dual modification" strategy. These two processes work synergistically with the hot-pressing co-curing process in step S4: during co-curing, the active functional groups in the surface-modified prepreg chemically bond with the active groups on the surface of the surface-modified compound rubber sheet or form an interpenetrating network structure, thereby establishing a strong chemical bonding interface between the composite material layer and the rubber layer, avoiding problems such as adhesive aging and interfacial delamination in traditional step-by-step bonding processes. This "dual modification + co-curing" combination is the key technical feature of this invention for achieving high interfacial bonding strength, excellent flexibility, and long-term structural stability. Simultaneously, the process flow is simple and controllable, which helps to shorten the production cycle, reduce costs, and meet the stability requirements of industrial-scale production.

[0010] Furthermore, in step S1, the thermoplastic polymer is selected from at least one of the following: polyarylether polymers containing a diazonaphthone structure, polysulfone, polyethersulfone, polyetherketone, polycaprolactone, polyvinyl alcohol, polyacrylonitrile, polyurethane, polyamide, polyimide, polyvinyl chloride, polystyrene, and polymethyl methacrylate.

[0011] Furthermore, in step S1, the polyarylether polymer containing a diazanaphthone structure is selected from at least one of polyarylether ketone containing a diazanaphthone structure, polyarylether sulfone containing a diazanaphthone structure, polyarylether nitrile containing a diazanaphthone structure, polyarylether nitrile ketone containing a diazanaphthone structure, polyarylether nitrile sulfone containing a diazanaphthone structure, polyarylether sulfone ketone containing a diazanaphthone structure, and polyarylether nitrile sulfone ketone containing a diazanaphthone structure.

[0012] Furthermore, in step S1, the number-average molecular weight of the thermoplastic polymer is 1.0 × 10⁻⁶. 4 ~2.0×10 5 g / mol.

[0013] Furthermore, in step S1, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, tetrahydrofuran, acetone, trimethyl sulfoxide, and dimethylpyrrolidone.

[0014] Furthermore, in step S1, the nanofiller is selected from at least one of carbon nanotubes, functionalized modified carbon nanotubes, nano-silica, graphene, boron nitride, nano-metals, and nano-metal oxides.

[0015] Furthermore, in step S1, the concentration of the thermoplastic polymer in the solvent is 20-30 wt%.

[0016] Furthermore, in step S1, the mass ratio of the nanofiller to the thermoplastic polymer is (0.005~0.04):1.0.

[0017] Furthermore, in step S1, the method for preparing the nanofiber membrane loaded with nanofillers includes electrospinning, air-jet spinning, and centrifugal spinning.

[0018] Furthermore, in step S1, the diameter of the nanofiber membrane loaded with nanofiller is 0.3-2.0 μm.

[0019] Furthermore, in step S1, the thickness of the nanofiber membrane loaded with nanofiller is 5-30 μm.

[0020] Furthermore, in step S1, the surface modification treatment of the nanofiber membrane loaded with nanofiller is plasma treatment, and the treatment parameters are: time 30~150s, power 50~100W.

[0021] Furthermore, in step S2, the raw rubber is selected from at least one of EPDM rubber, natural rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, silicone rubber, and fluororubber.

[0022] Furthermore, in step S2, the additives include at least one of sulfur, dicumyl peroxide, benzoyl peroxide, phenolic resin, zinc oxide, magnesium oxide, and stearic acid.

[0023] Furthermore, in step S2, the filler includes at least one of carbon black, calcium carbonate, paraffin oil, and antioxidant.

[0024] Furthermore, in step S2, the mass ratio of the raw rubber, additives and fillers is 100:(4-15):(40-150).

[0025] Furthermore, in step S2, the thickness of the compounded rubber sheet is 0.03-0.30 mm.

[0026] Furthermore, in step S2, the surface modification methods of the compound include plasma modification, ozone modification, and ultraviolet light modification.

[0027] Furthermore, in step S3, the prepreg is selected from at least one of carbon fiber prepreg, aramid fiber prepreg, basalt fiber prepreg, glass fiber prepreg, and ultra-high molecular weight polyethylene fiber prepreg.

[0028] Furthermore, in step S3, the surface modification treatment of the prepreg is plasma treatment, with the following parameters: time 50~600s, power 100~500W.

[0029] Furthermore, in step S4, the layer ratio of the surface-modified prepreg, the surface-modified compound sheet, and the nanofiber membrane loaded with nanofillers is (4-40):(1-8):(2-39).

[0030] Furthermore, in step S4, the mass ratio of the surface-modified prepreg to the nanofiber membrane loaded with nanofiller is 1:(0.05-0.80).

[0031] Furthermore, in step S4, the preset layup structure is an alternating layup structure, a sandwich-type layup structure, or a double-layer structure.

[0032] Furthermore, in step S4, the parameters for hot-press co-curing are: temperature 170~190℃, pressure 1~20 MPa, and holding time 90~120 min.

[0033] In a second aspect, the present invention provides a composite elastic splint, which is prepared by the preparation method described in the first aspect. The composite elastic splint includes a composite material layer and a rubber layer bonded by co-curing. The composite material layer is formed by co-curing a surface-modified prepreg and a surface-modified nanofiber membrane loaded with nanofillers, and the surface-modified nanofiber membrane loaded with nanofillers is disposed between adjacent surface-modified prepregs.

[0034] This invention constructs a rigid-flexible composite system by designing a layup structure consisting of a composite material layer and a rubber layer formed by the co-curing of a surface-modified prepreg and a surface-modified nanofiber membrane loaded with nanofillers. The rubber layer provides elastic recovery and cushioning, while the composite material layer provides high-stiffness support. A surface-modified nanofiber membrane loaded with nanofillers is positioned between adjacent surface-modified prepreg layers. This composite system allows for flexible adjustment of the layup ratio and structure according to the battery's deformation characteristics, achieving a precise match between constraint strength and elastic adaptability.

[0035] Furthermore, the thickness of the composite elastic clamp is 0.5-8.0 mm.

[0036] Thirdly, the present invention provides an application of the composite elastic clamp as described in the second aspect in suppressing volume expansion during the charging and discharging of ultra-high energy density lithium battery packs.

[0037] Compared with the prior art, the beneficial effects of the present invention include at least one of the following: 1) Effectively solves the problem of easy delamination in laminated boards, improving interface bonding and toughening effect. This invention introduces a surface-modified nanofiber membrane loaded with nanofillers between adjacent prepregs. The surface-modified nanofibers possess a micro-nano-scale uneven structure, significantly improving the surface roughness and surface energy of the fibers. Furthermore, the high specific surface area and active groups of the nanofillers enhance the adhesion between the fibers and the prepreg resin, and combined with the pull-out and bridging energy dissipation mechanism of thermoplastic fibers, multi-scale toughening is achieved. Simultaneously, surface modification treatments (such as plasma, ozone, or ultraviolet light) are applied to both the prepreg and the compounded rubber sheet, promoting chemical bonding between the prepreg resin and the rubber during co-curing. These synergistic effects significantly improve the interlaminar shear strength and interfacial bonding quality of the composite layer, effectively suppressing the defects of traditional fiber-reinforced laminates, such as easy delamination and uneven stress transmission.

[0038] 2) Achieve a rigid-flexible integrated structural design to meet the constraints and buffering requirements of battery dynamic deformation. This invention constructs a rigid-flexible composite system by combining surface-modified compounded rubber sheets (rubber layer) with prepreg and nanofiber membranes (composite material layer) in a predetermined layup structure. The composite material layer provides rigid support with high specific strength and high modulus, effectively constraining the volume expansion during battery charging and discharging; the rubber layer endows the sandwich panel with excellent elastic recovery and deformation buffering capabilities, enabling it to adapt to the periodic volume changes of the electrodes and absorb dynamic stress. Compared with purely rigid laminates, the sandwich panel of this invention significantly improves the maximum bending displacement (flexibility) while maintaining high flexural strength and modulus. Furthermore, by adjusting the layup ratio, fiber type, and rubber material, the stiffness and elasticity can be controlled within a wide range to meet the differentiated needs of different application scenarios.

[0039] 3) The co-curing integrated molding process is adopted to ensure overall performance and manufacturing efficiency. This invention employs a hot-press co-curing process, simultaneously curing the resin in the surface-modified prepreg and vulcanizing the rubber in the surface-modified compound sheet within a single thermal cycle. This allows the two phases to interpenetrate and cross-link at the interface, forming a dense, defect-free integral structure. This process avoids the weak bonding interface problem caused by traditional step-by-step molding (curing / vulcanizing before bonding), significantly enhancing the interfacial bond strength between the rubber layer and the composite material layer, and suppressing interlayer delamination. Simultaneously, the process flow is simple and controllable, which helps to shorten the production cycle, reduce costs, and meet the stability requirements of industrial-scale production.

[0040] 4) The materials are highly versatile and their performance can be customized. The technical solution of this invention has broad applicability to various types of thermoplastic polymers, nanofillers, rubber matrices, and fiber prepregs. Different material combinations (such as carbon fiber / EPDM rubber, glass fiber / natural rubber, etc.) can all obtain composite plywood with high mechanical strength, good toughness, and elastic deformation capability through the same preparation process. Users can flexibly select material systems, layup structures, and process parameters according to the deformation characteristics, spatial constraints, and mechanical requirements of specific application scenarios to achieve a continuous performance spectrum customization from "high strength and high toughness" to "high elasticity and cushioning".

[0041] 5) "Dual modification + co-curing" synergistically enhances interfacial chemical bonding and long-term structural stability This invention employs a "dual modification" strategy, involving surface modification treatments of both the prepreg and the compound rubber sheet, combined with a hot-press co-curing process. This allows the active groups in the prepreg to chemically bond with or form an interpenetrating network structure on the surface of the compound rubber sheet during curing / vulcanization. Compared to modifying only a single phase or using a step-by-step bonding process, this "dual modification + co-curing" significantly improves the interfacial bonding strength. In step-by-step processes, adhesive aging or interfacial debonding are common failure modes, while the integrated interface formed by co-curing in this invention has no adhesive layer and maintains structural integrity under long-term dynamic stress. The dual modification enables the nanofiber membrane, resin, and rubber three-phase interfaces to achieve good chemical affinity, further amplifying the interlayer toughening effect and preventing delamination or peeling of the plywood under repeated alternating stress.

[0042] 6) Comprehensively improves battery confinement performance and safety, with wide applicability. The composite elastic clamp of this invention can tightly fit the surface of an ultra-high energy density lithium battery pack. During charging and discharging, the rigid composite material layer provides continuous and effective circumferential constraint force, suppressing lattice distortion and volume expansion of the lithium metal electrode; the elastic rubber layer buffers dynamic stress, preventing gaps or relative slippage between the clamp and the battery; the strong interlayer bonding ensures that the clamp does not experience fatigue failure under long-term cyclic stress. Thus, the structural stability of the battery pack is guaranteed, cycle life is significantly extended, and safety is greatly improved, meeting the stringent requirements of high-energy-density energy storage systems in cutting-edge fields such as unmanned equipment and electric vehicles. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0044] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0045] In a first aspect, the present invention provides a method for preparing a composite elastic clamping plate, comprising the following steps: S1. Add thermoplastic polymer and nanofiller to solvent, disperse by ultrasonication to prepare nanofiber membrane loaded with nanofiller, and then perform surface modification treatment on nanofiber membrane loaded with nanofiller. S2. Mix rubber with additives and fillers to form a compound, hot press the compound into a sheet, and perform surface modification treatment on the compound sheet. S3. Surface modification treatment of the prepreg; S4. The surface-modified compound rubber sheet obtained in step S2 and the surface-modified prepreg obtained in step S3 are combined and laid according to a preset layup structure, and the surface-modified nanofiber membrane loaded with nanofillers obtained in step S1 is laid between adjacent surface-modified prepregs; the laid-up system is placed in a mold and co-cured by hot pressing. During the co-curing process, the resin in the prepreg is cured, and the rubber in the compound rubber sheet is vulcanized to obtain the composite elastic sandwich panel.

[0046] This invention introduces a surface-modified nanofiber membrane loaded with nanofillers between adjacent prepregs. The surface-modified nanofibers possess a micro-nano-scale uneven structure, significantly improving the surface roughness and surface energy of the fibers. Furthermore, the high specific surface area and active groups of the nanofillers enhance the adhesion between the fibers and the prepreg resin, and combined with the pull-out and bridging energy dissipation mechanism of thermoplastic fibers, multi-scale toughening is achieved. Simultaneously, surface modification treatments (such as plasma, ozone, or ultraviolet light) are applied to both the prepreg and the compounded rubber sheet, promoting chemical bonding between the prepreg resin and the rubber during co-curing. These synergistic effects significantly improve the interlaminar shear strength and interfacial bonding quality of the composite layer, effectively suppressing the defects of traditional fiber-reinforced laminates, such as easy delamination and uneven stress transmission.

[0047] This invention constructs a rigid-flexible composite system by combining surface-modified rubber sheets (rubber layer) with prepreg and nanofiber membranes (composite material layer) in a pre-defined layup structure. The composite material layer provides rigid support with high specific strength and high modulus, effectively constraining volume expansion during battery charging and discharging. The rubber layer endows the sandwich panel with excellent elastic recovery and deformation buffering capabilities, enabling it to adapt to the periodic volume changes of the electrodes and absorb dynamic stress. Compared to purely rigid laminates, the sandwich panel of this invention maintains high flexural strength and modulus while significantly improving maximum flexural displacement (flexibility). Furthermore, by adjusting the layup ratio, fiber type, and rubber material, stiffness and elasticity can be controlled within a wide range to meet the differentiated needs of various application scenarios. This invention employs a hot-press co-curing process, simultaneously completing the curing of the resin in the surface-modified prepreg and the vulcanization of the rubber in the surface-modified rubber sheet within a single thermal cycle. This allows the two phases to interpenetrate and cross-link at the interface, forming a dense and defect-free integral structure. This process avoids the weak bonding interface problem caused by traditional step-by-step molding (curing / vulcanization before bonding), significantly enhancing the interfacial bonding strength between the rubber layer and the composite material layer and suppressing interlayer delamination. The surface modification treatment of the compound rubber sheet in step S2 and the surface modification treatment of the prepreg in step S3 constitute a "dual modification" strategy. These two processes work synergistically with the hot-pressing co-curing process in step S4: during co-curing, the active functional groups in the surface-modified prepreg chemically bond with the active groups on the surface of the surface-modified compound rubber sheet or form an interpenetrating network structure, thereby establishing a strong chemical bonding interface between the composite material layer and the rubber layer, avoiding problems such as adhesive aging and interfacial delamination in traditional step-by-step bonding processes. This "dual modification + co-curing" combination is the key technical feature of this invention for achieving high interfacial bonding strength, excellent flexibility, and long-term structural stability. Simultaneously, the process flow is simple and controllable, which helps to shorten the production cycle, reduce costs, and meet the stability requirements of industrial-scale production.

[0048] As an optional implementation, in step S1, the thermoplastic polymer is selected from at least one of the following: polyarylether polymers containing diazonaphthone structures, polysulfone, polyethersulfone, polyetherketone, polycaprolactone, polyvinyl alcohol, polyacrylonitrile, polyurethane, polyamide, polyimide, polyvinyl chloride, polystyrene, and polymethyl methacrylate.

[0049] As an optional implementation, in step S1, the number-average molecular weight of the thermoplastic polymer is 1.0 × 10⁻⁶. 4 ~2.0×10 5 g / mol, for example, can be 1.0 × 10⁻⁶ g / mol. 4 g / mol, 1.5×10 4 g / mol, 2.2×10 4 g / mol, 3×10 4 g / mol, 5.0×10 4 g / mol, 8×10 4 g / mol, 1.5×10 5 g / mol or 2.0 × 10 5 g / mol.

[0050] As an optional implementation, in step S1, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, tetrahydrofuran, acetone, trimethyl sulfoxide, and dimethylpyrrolidone.

[0051] As an optional implementation, in step S1, the nanofiller is selected from at least one of carbon nanotubes, functionalized modified carbon nanotubes, nano-silica, graphene, boron nitride, nano-metals, and nano-metal oxides.

[0052] This invention further limits the types of thermoplastic polymers, solvents, and nanofillers, which can ensure the compatibility and dispersibility of nanofillers with thermoplastic polymers, thereby improving the interfacial bonding performance and toughness of the prepared composite material layer.

[0053] As an optional implementation, in step S1, the polyarylether polymer containing a diazanaphthone structure is selected from at least one of polyarylether ketone containing a diazanaphthone structure, polyarylether sulfone containing a diazanaphthone structure, polyarylether nitrile containing a diazanaphthone structure, polyarylether nitrile ketone containing a diazanaphthone structure, polyarylether nitrile sulfone containing a diazanaphthone structure, polyarylether sulfone ketone containing a diazanaphthone structure, and polyarylether nitrile sulfone ketone containing a diazanaphthone structure.

[0054] As an optional implementation, in step S1, the concentration of the thermoplastic polymer in the solvent is 20-30 wt%, for example, it can be 20 wt%, 25 wt%, or 30 wt%.

[0055] As an optional implementation, in step S1, the mass ratio of the nanofiller to the thermoplastic polymer is (0.005~0.04):1.0, for example, it can be 0.005:1.0, 0.01:1.0, 0.015:1.0, 0.02:1.0, 0.025:1.0, 0.03:1.0, 0.035:1.0 or 0.04:1.0.

[0056] This invention controls the concentration of thermoplastic polymer in the solvent to 20-30 wt%, giving the spinning solution suitable viscosity and conductivity, thereby enabling the stable formation of continuous and uniform nanofibers during the spinning process. Simultaneously, the mass ratio of nanofiller to thermoplastic polymer is limited to (0.005-0.04):1.0, which is a verified optimal range. If the ratio is too low, the reinforcing and toughening effect of the nanofiller is not significant, and its high specific surface area and the interfacial strengthening effect of active groups cannot be fully utilized; if the ratio is too high, it easily leads to filler agglomeration, which in turn damages the uniformity of the fibers and deteriorates the mechanical properties of the composite material. This limitation ensures that the nanofiller is uniformly dispersed and maximizes its reinforcing and toughening effect.

[0057] As an optional implementation, in step S1, the method for preparing the nanofiber membrane loaded with nanofillers includes electrospinning, air-jet spinning, and centrifugal spinning.

[0058] This invention employs multiple spinning processes to prepare nanofiber toughening phases, breaking the structural limitations of single spinning methods. It allows for flexible selection of appropriate spinning pathways based on the actual needs of interlayer toughening in composite materials. Diverse spinning methods can endow nanofibers with different microstructures, orientations, and film structures, providing multiple technical pathways for differentiated design of interlayer toughening phases and meeting the personalized requirements for the morphology and distribution of toughening phases in different systems. By rationally selecting spinning preparation methods, the overlapping state and function of nanofibers between layers can be stably controlled, fully leveraging the crack-resistant, bridging, and energy-dissipating effects of nanofibers with different structures. This further enhances the controllability and applicability of interlayer toughening effects, providing more comprehensive and flexible process support for optimizing the interlayer toughness and overall mechanical properties of composite materials.

[0059] As an optional implementation, in step S1, the diameter of the nanofiber membrane loaded with nanofiller is 0.3-2.0 μm, for example, it can be 0.3 μm, 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.5 μm or 2.0 μm.

[0060] As an optional implementation, in step S1, the thickness of the nanofiber membrane loaded with nanofiller is 5-30 μm, for example, it can be 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 28 μm or 30 μm.

[0061] As an optional implementation, in step S1, the surface modification treatment of the nanofiber membrane loaded with nanofillers is plasma treatment, and the treatment parameters are: time 30~150s, for example 30s, 50s, 70s, 90s, 110s, 130s or 150s, power 50~100W, for example 50W, 60W, 70W, 80W, 90W or 100W.

[0062] As an optional implementation, in step S2, the raw rubber is selected from at least one of EPDM rubber, natural rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, silicone rubber, and fluororubber.

[0063] As an optional implementation, in step S2, the additive includes at least one of sulfur, dicumyl peroxide, benzoyl peroxide, phenolic resin, zinc oxide, magnesium oxide, and stearic acid.

[0064] As an optional implementation, in step S2, the filler includes at least one of carbon black (carbon black N550, carbon black N330, white carbon black), calcium carbonate, paraffin oil, and antioxidants (antioxidant A, antioxidant D, antioxidant 4020, antioxidant RD).

[0065] As an optional implementation, in step S2, the mass ratio of the raw rubber, additives and fillers is 100:(4-15):(40-150), for example, it can be 100:12:132, 100:12:82, 100:4.5:40.5 or 100:8:51.

[0066] This invention specifically defines the base material of the "mixed rubber" in step S2, ensuring that the resulting rubber layer possesses the required elasticity, durability, and process compatibility with the composite material during co-curing. The listed rubbers (EPDM, natural rubber, styrene-butadiene rubber, etc.) cover a wide range from general-purpose to special high-performance types, with varying elastic moduli, temperature resistance, and chemical resistance. This allows for the selection of the most suitable rubber based on the specific operating environment of the battery (such as temperature and electrolyte type), and the selection of appropriate additives and fillers based on the chosen rubber, thereby achieving customization of the interlayer's elastic properties.

[0067] As an optional implementation, in step S2, the thickness of the compounded rubber sheet is 0.03-0.30 mm, for example, it can be 0.03 mm, 0.05 mm, 0.08 mm, 0.10 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.20 mm, 0.24 mm, 0.25 mm or 0.30 mm.

[0068] As an optional implementation, in step S2, the surface modification method of the compound includes plasma modification, ozone modification, and ultraviolet light modification.

[0069] This invention significantly improves the interfacial wettability and bonding strength between the rubber phase and the resin matrix by employing multiple surface activation methods on the rubber compound. The flexible selection of various modification methods allows for precise optimization of the interfacial bonding state according to the needs of the composite material system, reducing defects such as interfacial debonding and porosity, enhancing interfacial stress transfer efficiency, and providing a stable and reliable interfacial control scheme for further improving key mechanical properties of the composite material, such as interlaminar toughness and interfacial shear strength.

[0070] As an optional implementation, in step S3, the prepreg is selected from at least one of carbon fiber prepreg, aramid fiber prepreg, basalt fiber prepreg, glass fiber prepreg, and ultra-high molecular weight polyethylene fiber prepreg.

[0071] In step S3 of an optional implementation, the surface modification treatment of the prepreg is plasma treatment, and the treatment parameters are: time 50~600s, for example 50s, 100s, 200s, 300s, 400s, 500s or 600s, and treatment power 100~600W, for example 100W, 200W, 230W, 300W, 350W, 400W, 500W or 600W.

[0072] As an optional implementation, in step S4, the layer ratio of the surface-modified prepreg, the surface-modified compound sheet, and the nanofiber membrane loaded with nanofillers is (4-40):(1-8):(2-39), for example, it can be 12:1:11, 4:1:2, 40:1:39, 12:4:8, 8:4:4, or 12:1:10.

[0073] As an optional implementation, in step S4, the mass ratio of the surface-modified prepreg to the nanofiber membrane loaded with nanofillers is 1:(0.05-0.80), for example, it can be 1:0.05, 1:0.175, 1:0.20, 1:0.40, 1:0.60 or 1:0.80.

[0074] As an optional implementation, in step S4, the preset layup structure is an alternating layup structure, a sandwich-type layup structure, or a double-layer structure.

[0075] As an optional implementation, in step S4, the parameters for hot-press co-curing are: temperature of 170~190℃, for example, 170℃, 180℃ or 190℃; pressure of 1~20 MPa, for example, 1MPa, 5MPa, 8MPa, 10MPa, 15MPa or 20MPa; and holding time of 90~120 min, for example, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min or 120 min.

[0076] The temperature range (170~190℃) and holding time (90~120 min) for hot-press co-curing set in this invention are optimized process windows that can simultaneously meet the thermal history required for the curing reaction of commonly used prepregs and the vulcanization reaction of the selected rubber (such as EPDM), which is key to achieving high-quality co-curing. The set pressure range (1~20 MPa) can effectively expel interlayer gas during the curing process, compact each layup, ensure that there are no pores inside the plywood and no gaps between layers, and obtain accurate product dimensions.

[0077] In a second aspect, the present invention provides a composite elastic splint, which is prepared by the preparation method described in the first aspect. The composite elastic splint includes a composite material layer and a rubber layer bonded by co-curing. The composite material layer is formed by co-curing a surface-modified prepreg and a surface-modified nanofiber membrane loaded with nanofillers, and the surface-modified nanofiber membrane loaded with nanofillers is disposed between adjacent surface-modified prepregs.

[0078] This invention constructs a rigid-flexible composite system by designing a layup structure consisting of a composite material layer and a rubber layer formed by the co-curing of a surface-modified prepreg and a surface-modified nanofiber membrane loaded with nanofillers. The rubber layer provides elastic recovery and cushioning, while the composite material layer provides high-stiffness support. A surface-modified nanofiber membrane loaded with nanofillers is positioned between adjacent surface-modified prepreg layers. This composite system allows for flexible adjustment of the layup ratio and structure according to the battery's deformation characteristics, achieving a precise match between constraint strength and elastic adaptability.

[0079] As an optional implementation, the thickness of the composite elastic clamp is 0.5-8.0 mm, for example, it can be 0.5 mm, 1.0 mm, 1.5 mm, 1.9 mm, 2.0 mm, 2.5 mm, 3.0 mm, 4.0 mm, 4.2 mm, 5.0 mm, 6.0 mm or 8.0 mm.

[0080] Thirdly, the present invention provides an application of the composite elastic clamp as described in the second aspect in suppressing volume expansion during the charging and discharging of ultra-high energy density lithium battery packs.

[0081] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0082] Example 1 This embodiment provides a method for preparing a composite elastic clamp, the specific steps of which are as follows: S1. Prepare nanofiber membranes loaded with nanofillers and perform surface modification treatment: Weigh 2 g of material with a number-average molecular weight of 2.2 × 10⁻⁶. 4 0.02 g of aminated carbon nanotubes (the mass ratio of nanofiller to thermoplastic polymer was 0.01:1.0) were added to 6 g of N,N-dimethylacetamide and ultrasonically dispersed to obtain a spinning solution with a concentration of 25 wt%. Aminated carbon nanotube-loaded nanofiber membranes (nanofibers with a diameter of 0.5 μm and a membrane thickness of approximately 10 μm) were prepared using electrospinning (voltage 25 kV, injection rate 0.008 ml / min, collecting roller speed 200 rpm, spinning time 60 min, receiving distance 20 cm). The obtained nanofiber membranes were then surface-modified using a plasma treatment system with a power of 80 W and a treatment time of 90 s. The structural expression of the repeating unit of the polyarylene ether ketone containing the diazanaphthone structure is as follows: .

[0083] S2. Prepare compound rubber sheets and perform surface modification treatment: EPDM rubber, dicumyl peroxide, zinc oxide, stearic acid, carbon black N550, paraffin oil, and antioxidant RD were mixed evenly to prepare an EPDM rubber compound. The mass ratio of EPDM rubber, additives, and fillers was 100:12:132 (additives included 5g dicumyl peroxide, 5g zinc oxide, and 2g stearic acid; fillers included 80g carbon black N550, 50g paraffin oil, and 2g antioxidant RD). 1.0g of the compound was hot-pressed into a 0.13mm thick sheet. The resulting compound sheet was then surface-modified using a plasma treatment system at 360 W for 6 minutes.

[0084] S3 involves surface modification of the prepreg: Approximately 12.1g of carbon fiber prepreg (purchased from Yixing Fuyou Composite Materials Co., Ltd.) was selected and its surface was modified using a plasma treatment system with a treatment time of 300s and a power of 350W.

[0085] S4 layup and hot pressing co-curing: The surface-modified EPDM rubber compound sheet obtained in step S2 and the surface-modified carbon fiber prepreg obtained in step S3 are combined and laid according to a preset layering structure. The surface-modified nanofiber membrane loaded with aminated carbon nanotubes obtained in step S1 is then laid between adjacent layers of surface-modified carbon fiber prepreg. This embodiment employs a double-layer layering structure. The specific layering sequence is as follows: one layer of surface-modified EPDM rubber compound sheet and twelve layers of surface-modified carbon fiber prepreg are laid sequentially from bottom to top in the mold. A layer of surface-modified nanofiber membrane loaded with aminated carbon nanotubes obtained in step S1 is laid between every two adjacent layers of carbon fiber prepreg, for a total of 11 nanofiber membrane layers. The total amount of nanofiber membrane used is approximately 4.84 g, and the mass ratio of prepreg to nanofiber membrane is 1:0.40.

[0086] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 180℃, pressure 15 MPa, and holding time 120 min. During this process, the resin curing in the prepreg and the rubber vulcanization in the compounded rubber sheet were completed simultaneously, resulting in a composite elastic plywood (2.0 mm thick).

[0087] Example 2 This embodiment provides a method for preparing a composite elastic clamp, which differs from Embodiment 1 in steps S2, S3, and S4, as follows: S2. Prepare compound rubber sheets and perform surface modification treatment: Take 0.3 g of EPDM rubber compound (formula same as in Example 1) and hot press it into a compound sheet with a thickness of 0.03 mm. Perform surface modification treatment on the obtained compound sheet using a plasma treatment system (treatment power 360 W, treatment time 6 min).

[0088] S3 involves surface modification of the prepreg: Approximately 14.0g of carbon fiber prepreg (purchased from Jiangsu Hengshen Co., Ltd.) was selected and its surface was modified using a plasma treatment system. The treatment time was 300 s and the power was 350 W (the same as in Example 1).

[0089] S4 layup and hot pressing co-curing: The surface-modified EPDM rubber compound sheet obtained in step S2 and the surface-modified carbon fiber prepreg obtained in step S3 are combined and laid according to a preset layup structure. The surface-modified nanofiber membrane loaded with aminated carbon nanotubes obtained in step S1 is then laid between adjacent layers of surface-modified carbon fiber prepreg. This embodiment uses a sandwich-type layup structure, with the following sequence: two layers of surface-modified carbon fiber prepreg, one layer of surface-modified EPDM rubber compound sheet, and two layers of surface-modified carbon fiber prepreg are laid sequentially from bottom to top in the mold. A layer of surface-modified nanofiber membrane loaded with aminated carbon nanotubes obtained in step S1 is laid between each pair of adjacent carbon fiber prepreg layers (i.e., between the first and second layers, and between the fourth and fifth layers), for a total of two nanofiber membrane layers. The total amount of nanofiber membrane used is approximately 2.80 g, and the mass ratio of prepreg to nanofiber membrane is 1:0.20.

[0090] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 180℃, pressure 10MPa, and holding time 90min. During this process, the resin curing in the prepreg and the rubber vulcanization in the compounded rubber sheet were completed simultaneously, resulting in a composite elastic plywood (0.5mm thick).

[0091] Example 3 This embodiment provides a method for preparing a composite elastic clamp, the specific steps of which are as follows: S1. Preparation of nanofiber membranes loaded with nanofillers and surface modification treatment: Weigh 3 g of a product with a number average molecular weight of 3 × 10⁻⁶. 4 0.06 g of polyethersulfone and 0.06 g of nano-silica (the mass ratio of nanofiller to thermoplastic polymer is 0.02:1.0) were added to 7 g of dimethylpyrrolidone and ultrasonically dispersed to obtain a spinning solution with a concentration of approximately 30 wt%. Nanofiber membranes loaded with nano-silica (nanofiber diameter 2.0 μm, membrane thickness approximately 30 μm) were prepared by air-jet spinning (air pressure 0.15 MPa, solution flow rate 5 mL / h, receiving distance 20 cm, spinning time 60 min). The obtained nanofiber membranes loaded with nano-silica were then surface-modified using a plasma treatment system with a power of 50 W and a treatment time of 150 s. The structural formula of the polyethersulfone is as follows: , where n is a positive integer.

[0092] S2. Prepare compound rubber sheets and perform surface modification treatment: 2.5 g of EPDM rubber compound (formula same as in Example 1) was hot-pressed into a compound sheet with a thickness of 0.30 mm. The obtained compound sheet was then subjected to surface modification treatment using a plasma treatment system (treatment power 360 W, treatment time 6 min, same as in Example 1).

[0093] S3 involves surface modification of the prepreg: Approximately 27.2g of aramid fiber prepreg (purchased from Taihe New Materials Co., Ltd.) and approximately 35.2g of carbon fiber prepreg (purchased from Beijing Composite Materials Technology Co., Ltd.) were selected and surface modified using a plasma surface treatment system with a treatment time of 600s and a power of 100W.

[0094] S4 layup and hot pressing co-curing: The surface-modified EPDM rubber compound sheet obtained in step S2 is combined and laid with the surface-modified aramid fiber prepreg and carbon fiber prepreg obtained in step S3 according to a preset layup structure. The surface-modified nanofiber membrane loaded with nano-silica obtained in step S1 is then laid between adjacent surface-modified prepregs. This embodiment employs a double-layer layup structure, with the following sequence: from bottom to top, one layer of surface-modified EPDM rubber compound sheet, twenty layers of surface-modified aramid fiber prepreg, and twenty layers of surface-modified carbon fiber prepreg are laid in the mold. A layer of surface-modified nanofiber membrane loaded with nano-silica obtained in step S1 is laid between every two adjacent prepreg layers (a total of 39 interfaces), for a total of 39 nanofiber membrane layers. The total amount of nanofiber membrane used is approximately 3.12 g, and the mass ratio of prepreg (aramid + carbon fiber) to nanofiber membrane is 1:0.05.

[0095] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 180℃, pressure 20MPa, and holding time 90min. During this process, the resin curing in the prepreg and the rubber vulcanization in the compounded rubber sheet were completed simultaneously, resulting in a composite elastic plywood (thickness 8.0mm).

[0096] Example 4 This embodiment provides a method for preparing a composite elastic clamp, the specific steps of which are as follows: S1. Preparation of nanofiber membranes loaded with nanofillers and surface modification treatment: Weigh 2 g of material with a number average molecular weight of 2.0 × 10⁻⁶. 50.06 g of graphene and 0.06 g of polyacrylonitrile (mass ratio of nanofiller to thermoplastic polymer is 0.03:1.0) were added to 8 g of N,N-dimethylformamide and ultrasonically dispersed to obtain a spinning solution with a concentration of approximately 20 wt%. A graphene-loaded nanofiber membrane (nanofiber diameter 0.3 μm, membrane thickness approximately 18 μm) was prepared using a centrifugal spinning process (8000 rpm, receiving distance 20 cm, spinneret diameter 0.4 mm, solution flow rate 10 mL / h, spinning time 25 min, collecting roller speed 200 rpm). The obtained graphene-loaded nanofiber membrane was then surface-modified using a plasma treatment system with a power of 100 W and a treatment time of 30 s. The structural formula of the polyacrylonitrile is: , where n is a positive integer.

[0097] S2. Prepare compound rubber sheets and perform surface modification treatment: Natural rubber, sulfur, dicumyl peroxide, magnesium oxide, stearic acid, carbon black N330, and antioxidant A were mixed evenly to prepare a natural rubber compound. The mass ratio of natural rubber, additives, and fillers was 100:12:82 (additives included 0.5g sulfur, 4.5g dicumyl peroxide, 5g magnesium oxide, and 2g stearic acid; fillers included 80g carbon black N330 and 2g antioxidant A). 2.0g of the compound was hot-pressed into a 0.25mm thick sheet. The surface of the compound sheet was then modified using an ozone modification system with an ozone concentration of 50g / m³. 3 The gas flow rate was 1 L / mL, the treatment temperature was 30℃, and the treatment time was 10 min.

[0098] S3 involves surface modification of the prepreg: Approximately 20.5g of glass fiber prepreg (purchased from Taishan Glass Fiber Co., Ltd.) was selected and surface modified using a plasma surface treatment system with a treatment time of 50s and a power of 500W.

[0099] S4 layup and hot pressing co-curing: The surface-modified natural rubber compound sheet obtained in step S2 and the surface-modified glass fiber prepreg obtained in step S3 are combined and laid according to a preset layup structure. The surface-modified graphene-loaded nanofiber membrane obtained in step S1 is laid between adjacent surface-modified glass fiber prepregs. In this embodiment, an alternating layup structure is adopted, and the layup sequence is as follows: three layers of surface-modified glass fiber prepreg, one layer of surface-modified natural rubber compound sheet, three layers of surface-modified glass fiber prepreg, one layer of surface-modified natural rubber compound sheet, and so on, from bottom to top in the mold, for a total of 12 layers of glass fiber prepreg and 4 layers of compound sheet. A layer of surface-modified graphene-loaded nanofiber membrane obtained in step S1 is laid between every two adjacent layers of glass fiber prepreg (a total of 8 adjacent interfaces), for a total of 8 nanofiber membranes. The total amount of nanofiber membrane used is approximately 12.30 g, and the mass ratio of prepreg to nanofiber membrane is 1:0.60.

[0100] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 190℃, pressure 15MPa, and holding time 100min. During this process, the resin curing in the prepreg and the vulcanization of the rubber in the compound were completed simultaneously, resulting in a composite elastic plywood (2.5mm thick).

[0101] Example 5 This embodiment provides a method for preparing a composite elastic clamp, the specific steps of which are as follows: S1. Preparation of nanofiber membranes loaded with nanofillers and surface modification treatment: Weigh 2 g of a number-average molecular weight of 8 × 10⁻⁶. 4 0.01 g of boron nitride (nanofiller to thermoplastic polymer mass ratio of 0.005:1.0) and 0.1 g of polyurethane (polyurethane / mol) were added to 6 g of N,N-dimethylformamide and ultrasonically dispersed to obtain a spinning solution with a concentration of approximately 25 wt%. A boron nitride-loaded nanofiber membrane (nanofiber diameter 0.3 μm, membrane thickness approximately 5 μm) was prepared using a centrifugal spinning process (6000 rpm, receiving distance 25 cm, spinneret diameter 0.4 mm, solution flow rate 8 mL / h, spinning time 30 min, collecting roller speed 200 rpm). The obtained boron nitride-loaded nanofiber membrane was then surface-modified using a plasma treatment system with a power of 70 W and a treatment time of 110 s. The structural formula of the polyurethane is as follows: l, m, and n are all positive integers.

[0102] S2. Prepare compound rubber sheets and perform surface modification treatment: Chloroprene rubber, sulfur, zinc oxide, stearic acid, silica, and antioxidant D were mixed evenly to prepare a chloroprene rubber compound. The mass ratio of chloroprene rubber, additives, and fillers was 100:4.5:40.5 (additives included 0.5g sulfur, 3g zinc oxide, and 1g stearic acid; fillers included 40g silica and 0.5g antioxidant D). 1.6g of the compound was used to prepare a 0.18mm thick sheet. The surface of the compound sheet was treated with a UV modification system at a wavelength of 360nm and an intensity of 40mW / cm². 2 The processing time was 12 minutes, and the sample distance was 15 cm.

[0103] S3 involves surface modification of the prepreg: Approximately 15.2g of basalt fiber prepreg (purchased from Shixin Basalt Technology Co., Ltd.) was selected and surface-modified using a plasma surface treatment system with a treatment time of 400s and a power of 200W.

[0104] S4 layup and hot pressing co-curing: The surface-modified chloroprene rubber compound sheet obtained in step S2 and the surface-modified basalt fiber prepreg obtained in step S3 are combined and laid according to a preset layup structure, and the surface-modified boron nitride loaded nanofiber membrane obtained in step S1 is laid between adjacent surface-modified basalt fiber prepregs. This embodiment employs an alternating layer structure. The specific layering sequence is as follows: In the mold, from bottom to top, a layer of surface-modified chloroprene rubber compound sheet, two layers of surface-modified basalt fiber prepreg, another layer of surface-modified chloroprene rubber compound sheet, two layers of surface-modified basalt fiber prepreg, another layer of surface-modified chloroprene rubber compound sheet, two layers of surface-modified basalt fiber prepreg, another layer of surface-modified chloroprene rubber compound sheet, and two layers of surface-modified basalt fiber prepreg are laid. Between each pair of adjacent basalt fiber prepreg layers, a layer of surface-modified boron nitride-loaded nanofiber membrane prepared in step S1 is laid. A total of 4 layers of compound sheet, 8 layers of basalt fiber prepreg, and 4 layers of nanofiber membrane are laid. The total amount of nanofiber membrane used is approximately 12.16 g, and the mass ratio of prepreg to nanofiber membrane is 1:0.80.

[0105] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 180℃, pressure 8MPa, and holding time 105min. During this process, the resin curing in the prepreg and the rubber vulcanization in the compounded rubber sheet were completed simultaneously, resulting in a composite elastic plywood (1.9mm thick).

[0106] Example 6 This embodiment provides a method for preparing a composite elastic clamp, the specific steps of which are as follows: S1. Preparation of nanofiber membranes loaded with nanofillers and surface modification treatment: Weigh 2 g of material with a number average molecular weight of 1.5 × 10⁻⁶. 4 0.08 g of polyamide 6 and 0.08 g of nano-titanium dioxide (the mass ratio of nanofiller to thermoplastic polymer is 0.04:1.0) were added to 8 g of N,N-dimethylformamide and ultrasonically dispersed to obtain a spinning solution with a concentration of approximately 20 wt%. A nanofiber membrane loaded with nano-titanium dioxide (nanofiber diameter 1.2 μm, membrane thickness 12 μm) was prepared using electrospinning (voltage 30 kV, injection rate 0.012 ml / min, collecting roller speed 200 rpm, spinning time 45 min, receiving distance 15 cm). The obtained nanofiber membrane loaded with nano-titanium dioxide was then surface-modified using a plasma treatment system with a power of 90 W and a treatment time of 70 s. The structural formula of the polyamide 6 is as follows: , where n is a positive integer.

[0107] S2. Prepare compound rubber sheets and perform surface modification treatment: Styrene-butadiene rubber (SBR), phenolic resin, zinc oxide, stearic acid, calcium carbonate, and antioxidant 4020 were mixed evenly to prepare a SBR compound. The mass ratio of SBR, additives, and fillers was 100:8:51 (additives included 3g phenolic resin, 4g zinc oxide, and 1g stearic acid; fillers included 50g calcium carbonate and 1g antioxidant 4020). 2.1g of the compound was hot-pressed into a 0.24mm thick sheet. The compound sheet was then surface-treated using an ultraviolet (UV) light modification system with a wavelength of 360 nm and an intensity of 50mW / cm². 2 The processing time was 8 minutes, and the sample distance was 18 cm.

[0108] S3 involves surface modification of the prepreg: Aramid fiber prepreg (approximately 16.0g in weight, purchased from Inner Mongolia Aerospace New Materials Technology Co., Ltd.) was selected and subjected to plasma surface treatment for 500 seconds at a power of 230W.

[0109] S4. Lamination and hot pressing co-curing: The surface-modified styrene-butadiene rubber compound sheet obtained in step S2 and the surface-modified aramid fiber prepreg obtained in step S3 are combined and laid according to a preset layering structure. The surface-modified nanofiber membrane loaded with nano-titanium dioxide obtained in step S1 is then laid between adjacent surface-modified aramid fiber prepregs. This embodiment uses a sandwich-type layering structure, with the following layering sequence: six layers of surface-modified aramid fiber prepreg, one layer of surface-modified styrene-butadiene rubber compound sheet, and six layers of surface-modified aramid fiber prepreg are laid sequentially from bottom to top in the mold. A layer of surface-modified nanofiber membrane loaded with nano-titanium dioxide obtained in step S1 is laid between every two adjacent layers of aramid fiber prepreg (a total of 10 adjacent interfaces), for a total of 10 nanofiber membrane layers. The total amount of nanofiber membrane used is approximately 2.8g, and the mass ratio of prepreg to nanofiber membrane is 1:0.175.

[0110] The above-mentioned layup system was placed in a mold and subjected to a hot-press co-curing process. The co-curing parameters were: temperature 180℃, pressure 10MPa, and holding time 90min. During this process, the resin curing in the prepreg and the rubber vulcanization in the compounded rubber sheet were completed simultaneously, resulting in a composite elastic plywood (2.0mm thick).

[0111] Comparative Example 1 This comparative example provides a method for preparing a composite elastic clamping plate, for comparison with the embodiments of the present invention. The difference from Example 1 is that no nanofiber membrane with surface-modified loaded nanofillers is prepared or introduced as an interlayer toughening agent; all other steps and conditions remain consistent with Example 1. Specific differences are as follows: S1 No nanofiber membrane is prepared (step S1 of Example 1 is omitted).

[0112] S2 is the same as S2 in Example 1.

[0113] S3 is the same as S3 in Example 1.

[0114] S4 layup and hot pressing co-curing: The surface-modified EPDM rubber compound sheet obtained in step S2 and the surface-modified carbon fiber prepreg obtained in step S3 are combined and laid according to a preset layup structure. No nanofiber membrane is laid in this comparative example. The specific layup sequence is as follows: one layer of surface-modified EPDM rubber compound sheet and twelve layers of surface-modified carbon fiber prepreg are laid sequentially from bottom to top in the mold. The key difference from Example 1 is that no interlayer toughening material is laid between adjacent layers of carbon fiber prepreg. The hot-pressing co-curing parameters are the same as in S4 of Example 1.

[0115] Comparative Example 2 This comparative example provides a method for preparing a composite elastic clamping plate, for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that no nanofiller is added during the preparation of the nanofiber membrane; that is, a pure thermoplastic polymer nanofiber membrane without any filler loading but with surface modification is used as the interlayer toughening agent. All other steps and conditions remain consistent with Example 1. Specific differences are as follows: S1 Preparation of nanofiber membranes (without filler loading but with surface modification): In this step, the preparation process is basically the same as S1 in Example 1, but no aminated carbon nanotubes or any other nanofillers are added to the solution, and a pure polyarylether nitrile ketone nanofiber membrane is finally obtained.

[0116] S4 layup and hot pressing co-curing: In this step, the pure nanofiber membrane without filler prepared in step S1 of this comparative example is laid between adjacent surface-modified carbon fiber prepregs. The remaining layup structure, materials and co-curing process parameters are exactly the same as S4 of Example 1.

[0117] Comparative Example 3 This comparative example provides a method for preparing a composite elastic clamping plate, for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that nanofillers are added during the preparation of the nanofiber membrane, but no surface modification treatment is performed; that is, a thermoplastic polymer nanofiber membrane loaded with nanofillers but without surface modification is used as the interlayer toughening agent. All other steps and conditions remain consistent with Example 1. Specific differences are as follows: S1 Preparation of nanofiber membranes (loaded with filler but without surface modification): In this step, the preparation process is basically the same as S1 in Example 1, but the surface modification treatment of the obtained nanofiber membrane loaded with aminated carbon nanotubes is not performed using a plasma treatment system.

[0118] S4 layup and hot pressing co-curing: In this step, the nanofiber membrane loaded with aminated carbon nanotubes prepared in step S1 of this comparative example is laid between adjacent surface-modified carbon fiber prepregs. The remaining layup structure, materials and co-curing process parameters are exactly the same as those in S4 of Example 1.

[0119] Comparative Example 4 This comparative example provides a method for preparing a composite elastic plywood, for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that no surface modification treatment is performed on the prepreg and the compounded rubber sheet; all other steps and conditions remain the same as in Example 1. Specific differences are as follows: S2 Preparation of Compound Rubber Sheets (without surface modification): In this step, the preparation process of the compound rubber sheet is the same as S2 in Example 1, but after hot pressing, no plasma modification, ozone modification or ultraviolet light modification treatment is performed. The compound rubber sheet without surface modification is directly used for subsequent lay-up.

[0120] S3 prepreg (without surface modification): In this step, the selection of prepreg is the same as in S3 of Example 1, but without plasma surface treatment, the unmodified carbon fiber prepreg is used directly for subsequent lay-up.

[0121] S4 layup and hot pressing co-curing: In this step, the layup uses unmodified compound rubber sheets and unmodified carbon fiber prepreg. The remaining layup structure (one layer of EPDM rubber compound sheet, twelve layers of carbon fiber prepreg, and a layer of surface-modified nanofiber membrane loaded with aminated carbon nanotubes laid between adjacent prepregs), material usage, and hot-press co-curing process parameters are exactly the same as S4 in Example 1.

[0122] Comparative Example 5 This comparative example provides a method for preparing a composite elastic splint for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that a step-by-step curing process is used instead of a co-curing process; that is, the composite material layer and the vulcanized rubber layer are prepared separately first, and then bonded together with an adhesive. All other materials and basic processes remain consistent with Example 1. Specific differences are as follows: S2 prepares compounded rubber sheets, performs surface modification treatment, and then vulcanizes: In this step, the preparation process of the rubber compound sheet is the same as S2 in Example 1 (hot pressing the EPDM rubber compound into a sheet with a thickness of 0.13 mm). Then, the obtained rubber compound sheet is surface modified using a plasma treatment system with a treatment power of 360 W and a treatment time of 6 min (the same as S2 in Example 1). After the surface modification treatment, the rubber compound sheet is fully vulcanized to obtain a surface-modified and vulcanized rubber sheet.

[0123] S3 is the same as S3 in Example 1.

[0124] S4 Preparation of composite elastic splint (stepwise bonding): In this step, co-curing is not performed. The specific steps are as follows: 1) Twelve layers of surface-modified carbon fiber prepreg and eleven layers of surface-modified nanofiber membrane loaded with aminated carbon nanotubes laid between adjacent prepregs were sequentially laid and placed in a mold. The composite laminate was then hot-pressed and cured at 180°C and 15 MPa for 120 min to obtain the composite laminate. 2) After cleaning the surface of the surface-modified and vulcanized rubber sheet obtained in step S2, a layer of epoxy structural adhesive 3M DP420 (purchased from Kang Sheng Chemical Co., Ltd.) is uniformly coated on the bonding surface of the composite laminate and the rubber sheet. 3) Bond the two together and cure under pressure of 1.5 MPa at room temperature for 24 hours to obtain the final composite splice.

[0125] Comparative Example 6 This comparative example provides a method for preparing a composite elastic splint, for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that no rubber layer is introduced; only a composite laminate is used. All other materials and basic processes remain the same as in Example 1. Specific differences are as follows: S1 is the same as S1 in Example 1.

[0126] S2. Prepare compound rubber sheets and perform surface modification treatment: This step is omitted entirely. No rubber layer is prepared.

[0127] S3 is the same as S3 in Example 1.

[0128] S4 layup and hot-press curing (without rubber layer): In this step, the layup structure consists only of prepreg and interlayer nanofibers, without any rubber layer. The specific layup sequence is as follows: twelve layers of surface-modified carbon fiber prepreg are laid sequentially from bottom to top in the mold, and a layer of surface-modified nanofiber membrane loaded with aminated carbon nanotubes, obtained in step S1, is laid between each pair of adjacent carbon fiber prepreg layers, for a total of 11 nanofiber membrane layers. The total amount of nanofiber membrane and the mass ratio of prepreg to nanofiber membrane are consistent with S4 of Example 1.

[0129] The above-described layup system was placed in a mold and cured using a hot-pressing process (non-co-curing). The curing parameters were: temperature 180°C, pressure 15 MPa, and holding time 120 min. During this process, only the resin in the prepreg was cured, resulting in a pure composite laminate (without a rubber layer), with a thickness similar to the total thickness of the composite elastic sandwich panel in Example 1.

[0130] Comparative Example 7 This comparative example provides a method for preparing a composite elastic plywood, for comparison with the embodiments of the present invention. The difference between this method and Example 1 is that the prepreg is not surface-modified (i.e., the surface modification step of the prepreg is omitted), while the remaining steps and conditions are consistent with Example 1. Specific differences are as follows: S3 prepreg (without surface modification): In this step, the selection of prepreg is the same as in S3 of Example 1, but without plasma surface treatment, the unmodified carbon fiber prepreg is used directly for subsequent lay-up.

[0131] S4 layup and hot pressing co-curing: In this step, the layup uses plasma-modified compound rubber sheet and unmodified carbon fiber prepreg. The remaining layup structure (one layer of EPDM rubber compound sheet, twelve layers of carbon fiber prepreg, and a layer of surface-modified nanofiber membrane loaded with aminated carbon nanotubes laid between adjacent prepregs), material usage, and hot-press co-curing process parameters are exactly the same as S4 in Example 1.

[0132] Performance testing To verify the comprehensive performance of the composite elastic splint provided by this invention, key mechanical and interfacial performance tests were conducted on the composite elastic splints prepared in Examples 1-6 and Comparative Examples 1-6, according to relevant industry standards (referring to ASTM D790 test standard for testing the bending performance of the composite elastic splint; and referring to ISO 14130 test standard for testing the interlaminar shear performance of the composite elastic splint). The test results are shown in Table 1 below.

[0133] Table 1

[0134] As can be clearly seen from the test data in Table 1, the composite elastic plates prepared using the technical solutions of this invention in Examples 1-6 exhibit diverse performance characteristics in key indicators such as bending strength, bending modulus, maximum bending displacement (reflecting flexibility), and interlaminar shear strength, fully demonstrating the technical advantages and designability of this invention. A detailed analysis follows: 1. Synergistic effect of interlayer toughening system (nanofiber + nanofiller) The flexural strength (2415 MPa) and interlaminar shear strength (99 MPa) of Example 1 were significantly higher than those of Comparative Example 1 (1962 MPa, 83 MPa), and the maximum flexural displacement was also greater (6.94 mm), which was superior to that of Comparative Example 1 (6.21 mm). This directly demonstrates that the nanofiber membrane with loaded nanofillers introduced between adjacent prepregs can effectively bridge cracks, transfer stress, significantly improve the interfacial bonding performance, toughness, and overall load-bearing capacity of the composite layer, while maintaining good deformability.

[0135] Example 1 outperformed Comparative Example 2 (2022 MPa, 6.40 mm, 86 MPa) in flexural strength, maximum flexural displacement, and interlaminar shear strength. Comparative Example 2 also introduced a nanofiber membrane but did not add nanofillers. This indicates a synergistic toughening and reinforcing effect between nanofillers (such as aminated carbon nanotubes) and thermoplastic polymer nanofibers. The high specific surface area and active groups of the nanofillers further strengthened the interfacial bonding between the fibers and the resin matrix and participated in chemical reactions during co-curing, achieving "nanoscale reinforcement."

[0136] In Comparative Example 3, nanofiber membranes were prepared with added nanofillers (aminated carbon nanotubes), but no surface modification treatment was performed (i.e., the plasma treatment step was omitted). Its flexural strength was 2095 MPa, flexural modulus was 91 GPa, maximum flexural displacement was 6.34 mm, and interlaminar shear strength was 85 MPa. Compared to Example 1, all performance indicators of Comparative Example 3 decreased significantly: flexural strength decreased by approximately 13.2%, flexural modulus decreased by approximately 33.1%, maximum flexural displacement decreased by approximately 8.6%, and interlaminar shear strength decreased by approximately 14.1%. This comparative result indicates that even with nanofillers loaded in the nanofiber membrane, the toughening and strengthening effect will be significantly weakened without surface modification treatment. Compared to Comparative Example 2 (using pure thermoplastic polymer nanofiber membrane, without filler, and after surface modification), Comparative Example 3 showed only a limited increase in flexural strength (2095 vs 2022 MPa), with similar interlaminar shear strength (85 vs 86 MPa), and even slightly decreased flexural modulus (91 vs 94 GPa) and maximum flexural displacement (6.34 vs 6.40 mm). This indicates that without surface modification, the nanofiber membrane loaded with nanofillers cannot effectively expose the nanofillers or form a strong chemical bond with the resin matrix. Instead, the nanofillers may partially offset the toughening effect of the nanofibers themselves due to agglomeration or poor interfacial compatibility. From the perspective of interfacial chemistry and mechanical mechanisms, surface modification treatment (such as plasma treatment) can introduce active functional groups such as hydroxyl, carboxyl, and amino groups onto the nanofiber surface, while increasing surface roughness, thereby significantly improving the wettability and chemical bonding ability between the nanofibers and the prepreg resin. If this treatment is omitted, even if the nanofiller is present, its high specific surface area and active sites will not be able to effectively perform the functions of "bridging" and "stress transfer", which will lead to easy propagation of interlayer cracks, decrease in interfacial shear strength, and ultimately reflect a comprehensive deterioration in flexural strength, modulus and flexibility.

[0137] 2. The necessity of the synergistic effect of "dual modification + co-curing" The properties of Example 1, especially the interlaminar shear strength (99 MPa) and maximum flexural displacement (6.94 mm), are significantly higher than those of Comparative Example 4 (80 MPa, 5.93 mm) and Comparative Example 5 (61 MPa, 5.24 mm). In-depth analysis of these two comparative examples clearly reveals the indispensable synergistic relationship between "dual modification" (i.e., simultaneous surface modification of both the prepreg and the compound film) and "hot-press co-curing."

[0138] Comparative Example 4 omitted the surface modification treatment of the prepreg and compound rubber sheets, but still retained the nanofiber membrane and co-curing process. Its interlaminar shear strength (80 MPa) and maximum flexural displacement (5.93 mm) were significantly lower than those of Example 1 (99 MPa, 6.94 mm). This comparison demonstrates that even with the introduction of nanofiber membrane toughening and co-curing processes, without modification of both phases, the chemical affinity between the prepreg and compound rubber sheets is insufficient, preventing the formation of strong chemical bonds or interpenetrating networks at the interface, thus severely limiting the interfacial bonding strength and the overall flexibility of the plywood.

[0139] Comparative Example 7 only underwent plasma surface modification of the rubber compound sheet, while the prepreg was not subjected to any surface modification (i.e., "single modification"), but still retained the nanofiber membrane and hot-press co-curing process. The interlaminar shear strength of Comparative Example 6 was 87 MPa, the maximum flexural displacement was 6.13 mm, and the flexural modulus was 105 GPa, all significantly lower than that of Example 1 (99 MPa, 6.94 mm, 136 GPa). This comparative result further verifies the necessity of the "dual modification" strategy of this invention: if only the rubber phase is surface activated, while the surface of the prepreg (composite phase) remains inert, even with a co-curing process, it is difficult to form a sufficiently dense and strong chemical bond or interpenetrating network between the two phases. The lack of active functional groups on the prepreg surface limits its effective reaction with the modified rubber compound sheet and nanofiber membrane, leading to decreased interfacial bonding strength, reduced stress transfer efficiency, and impaired overall flexibility and rigidity of the plywood. Compared to Comparative Example 4 (both unmodified, interlaminar shear strength 80 MPa), Comparative Example 7 showed improved performance (87 MPa), but was still significantly lower than Example 1. This indicates that "dual modification" can better leverage the advantages of the co-curing process than "single modification," achieving a robust integrated interface between the composite material layer and the rubber layer, thereby obtaining optimal mechanical properties and long-term structural stability.

[0140] Comparative Example 5 involved surface modification of the prepreg and rubber compound sheets, but employed a step-by-step conventional process of "curing / vulcanizing separately first, then bonding," instead of co-curing. Its interlaminar shear strength (61 MPa) and maximum flexural displacement (5.24 mm) were the lowest among all samples, and its flexural strength (1852 MPa) was also significantly lower than that of Example 1 (2415 MPa). This comparison demonstrates that even with modification of the prepreg and rubber layer, if step-by-step bonding is used instead of co-curing, the modified active surface cannot undergo synchronous cross-linking with the resin during the curing / vulcanization process. The adhesive layer instead becomes a weak interfacial area, leading to a significant deterioration in mechanical properties.

[0141] Only when Example 1 simultaneously met the triple conditions of "prepreg modification, compound rubber sheet modification, and hot-press co-curing" did it achieve the highest interlaminar shear strength (99 MPa) and excellent maximum flexural displacement (6.94 mm). This fully demonstrates that the "dual modification + co-curing" of the present invention is not a simple superposition of features, but rather produces a significant synergistic effect: during the co-curing process, the surface-modified prepreg and the surface-modified compound rubber sheet undergo chemical bonding or form an interpenetrating network structure on their surfaces, thereby establishing an integrated, adhesive-free, and robust interface between the composite material layer and the rubber layer. This interface avoids the risks of adhesive aging and debonding in traditional step-by-step processes and significantly improves stress transfer efficiency, enabling the plywood to maintain structural integrity under long-term dynamic alternating stress.

[0142] If only the surface of the prepreg is modified without modifying the compound film (i.e., single modification), the chemical bonding or interpenetrating network at the interface of the two phases during co-curing is difficult to establish completely and effectively, and its interfacial bonding strength and plywood flexibility will be inferior to Example 1, which involves simultaneous dual modification.

[0143] 3. The rationality of rigid-flexible composite structure design Although Comparative Example 5 (without rubber layer) has a higher flexural modulus (114 GPa), its maximum flexural displacement (3.6 mm) is much lower than all examples containing rubber layers (the maximum flexural displacement of Examples 1-6 is 6.94–11.26 mm), indicating that it has the worst flexibility. This directly verifies the necessity of introducing a rubber layer to construct a "rigid-flexible" composite system. The rubber layer provides crucial elastic recovery and deformation buffering capabilities, enabling the sandwich panel to adapt to the periodic volume changes during battery charging and discharging, absorb dynamic stress impacts, and avoid battery damage or constraint failure that may occur due to insufficient deformation capacity of purely rigid laminates.

[0144] 4. Wide range of adjustable flexural modulus The flexural modulus reflects the stiffness characteristics of a material within its elastic deformation range. As can be seen from the data in Table 1: High-modulus systems: Examples 1 (136 GPa) and 3 (124 GPa) exhibit the highest flexural modulus. Both are reinforced with carbon fiber or carbon fiber / aramid fiber hybrids and have a low proportion of rubber layer (both are single-layer rubber). These high-modulus plates are suitable for applications requiring high constraint stiffness and can effectively suppress excessive battery expansion.

[0145] Medium modulus system: Example 6 (59 GPa) exhibits a medium modulus level. It is noteworthy that although Example 2 (63 GPa) uses carbon fiber reinforcement, its flexural modulus is significantly lower than other carbon fiber systems. This is closely related to its layup structure: the total thickness of Example 2 is only 0.5 mm, which has a significant impact on the overall flexural modulus. This phenomenon precisely illustrates that the present invention can achieve precise control of stiffness by adjusting the layup thickness.

[0146] Low-modulus systems: Examples 4 (43 GPa) and 5 (48 GPa) are reinforced with glass fiber and basalt fiber, exhibiting lower modulus but the highest maximum bending displacements (11.26 mm and 10.59 mm) among all samples, demonstrating excellent flexibility. These types of clamps are suitable for applications requiring high deformation compliance and the absorption of greater dynamic stress.

[0147] The above modulus gradient indicates that the present invention can achieve a wide range of adjustable stiffness (43-136 GPa) of the clamp by selecting different reinforcing fibers, adjusting the rubber layer ratio and the layup structure, and accurately matching the constraint requirements of different battery systems.

[0148] 5. The universality and customizability of the technical solution Examples 2 to 6 systematically varied the fiber reinforcement materials (such as aramid, glass fiber, basalt fiber), rubber matrix (such as natural rubber, neoprene rubber, styrene-butadiene rubber), nanofillers (such as nano-silica, graphene, boron nitride, nano-titanium dioxide), and layup structures (such as sandwich type, alternating type, bilayer structure). Test results show that the preparation method of this invention has high material versatility and performance designability.

[0149] The performance data from these examples form a continuous spectrum from "high strength and high toughness" to "high elasticity and cushioning". For example, Example 1 (carbon fiber prepreg + EPDM rubber) achieved the highest flexural strength (2415 MPa) and flexural modulus (136 GPa), while maintaining a maximum flexural displacement of 6.94 mm, demonstrating excellent overall mechanical properties. Example 3 (aramid / carbon fiber blended prepreg and EPDM rubber) maintained high flexural strength (2018 MPa) and flexural modulus (124 GPa), while its maximum flexural displacement (7.35 mm) was more than twice that of the pure rigid plate in Example 5, demonstrating excellent rigidity-flexibility balance. Example 4 (glass fiber prepreg and natural rubber) exhibited another extreme performance orientation: its flexural strength (963 MPa) and flexural modulus (43 GPa) were relatively low, but it achieved the highest maximum flexural displacement (11.26 mm) of all samples, indicating that this combination is particularly suitable for applications requiring extremely high deformation cushioning capabilities.

[0150] Crucially, all Examples 1-6, which included rubber layers, exhibited significantly higher maximum flexural displacements (6.94-11.26 mm) than Comparative Example 5 (3.60 mm), a pure rigid composite material, representing increases of 93%-213%. This consistently and powerfully demonstrates that the "rigid-flexible" composite system constructed using this invention can fundamentally improve the elastic deformation and energy absorption capacity of the interlayer under load, thus better adapting to the periodic volume changes during battery charging and discharging. Simultaneously, the interlaminar shear strengths (65-99 MPa) of these examples remained at a high level and were generally superior to Comparative Example 4 (61 MPa), which employed a step-by-step bonding process, further validating the versatility of the co-curing process in ensuring interface reliability across different material systems.

[0151] Therefore, this invention not only provides a series of high-performance specific composite clamp formulations (such as Examples 1-6), but also provides a flexible and adjustable preparation strategy. Users can precisely customize the balance between stiffness, strength and elasticity of the clamp by selecting different fibers, rubbers, nanofillers and layup structures according to the deformation characteristics, spatial constraints and mechanical requirements of a specific battery system, thereby achieving the optimal configuration of constraint effectiveness and deformation adaptability.

[0152] In summary, this invention successfully fabricates a composite elastic clamping plate with high mechanical strength, excellent interlayer toughness, good elastic deformation capability, and strong interfacial bonding through the synergistic effect of three key technologies: introducing nanofiber membranes loaded with nanofillers into the interlayer, surface modification treatment of prepreg and compounded rubber sheets, and hot-press co-curing process. This clamping plate effectively meets the dual requirements of ultra-high energy density lithium battery packs for dynamic suppression of volume expansion and long-term structural stability. Furthermore, this technical solution offers a wide range of material selection options and customizable performance capabilities, flexibly adapting to the differentiated requirements of various application scenarios.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite elastic clamping plate, characterized in that, Includes the following steps: S1. Add thermoplastic polymer and nanofiller to a solvent, disperse by ultrasonication to prepare a nanofiber membrane loaded with nanofiller, and then perform surface modification treatment on the nanofiber membrane loaded with nanofiller. S2. Mix rubber with additives and fillers to form a compound, hot press the compound into a sheet, and perform surface modification treatment on the compound sheet. S3. Surface modification treatment of the prepreg; S4. The surface-modified compound rubber sheet obtained in step S2 and the surface-modified prepreg obtained in step S3 are combined and laid according to a preset layup structure, and the surface-modified nanofiber membrane loaded with nanofillers obtained in step S1 is laid between adjacent surface-modified prepregs; the laid-up system is placed in a mold and co-cured by hot pressing. During the co-curing process, the resin in the prepreg is cured, and the rubber in the compound rubber sheet is vulcanized to obtain the composite elastic sandwich panel.

2. The preparation method according to claim 1, characterized in that, In step S1, the thermoplastic polymer is selected from at least one of the following: polyarylether polymers containing a diazonaphthone structure, polysulfone, polyethersulfone, polyetherketone, polycaprolactone, polyvinyl alcohol, polyacrylonitrile, polyurethane, polyamide, polyimide, polyvinyl chloride, polystyrene, and polymethyl methacrylate; and / or, The thermoplastic polymer has a number-average molecular weight of 1.0 × 10⁻⁶. 4 ~2.0×10 5 g / mol; and / or, The solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, tetrahydrofuran, acetone, trimethyl sulfoxide, and dimethylpyrrolidone; and / or, The nanofiller is selected from at least one of carbon nanotubes, functionalized modified carbon nanotubes, nano-silica, graphene, boron nitride, nano-metals, and nano-metal oxides.

3. The preparation method according to claim 1, characterized in that, In step S1, the polyarylether polymer containing a diazanaphthone structure is selected from at least one of the following: polyarylether ketone containing a diazanaphthone structure, polyarylether sulfone containing a diazanaphthone structure, polyarylether nitrile containing a diazanaphthone structure, polyarylether nitrile ketone containing a diazanaphthone structure, polyarylether nitrile sulfone containing a diazanaphthone structure, polyarylether sulfone ketone containing a diazanaphthone structure, and polyarylether nitrile sulfone ketone containing a diazanaphthone structure; and / or, The concentration of the thermoplastic polymer in the solvent is 20-30 wt%; and / or, The mass ratio of the nanofiller to the thermoplastic polymer is (0.005~0.04):1.

0.

4. The composite elastic clamping plate according to claim 1, characterized in that, In step S1, the method for preparing the nanofiber membrane loaded with nanofillers includes electrospinning, air-jet spinning, and centrifugal spinning; and / or, The diameter of the nanofiber membrane loaded with nanofiller is 0.3-2.0 μm; and / or, The thickness of the nanofiber membrane loaded with nanofillers is 5-30 μm; and / or, The surface modification treatment of the nanofiber membrane loaded with nanofiller is plasma treatment, with the following parameters: time 30~150s, power 50~100W.

5. The preparation method according to claim 1, characterized in that, In step S2, the raw rubber is selected from at least one of EPDM rubber, natural rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, silicone rubber, and fluororubber; and / or, The additives include at least one selected from sulfur, dicumyl peroxide, benzoyl peroxide, phenolic resin, zinc oxide, magnesium oxide, and stearic acid; and / or, The filler includes at least one of carbon black, calcium carbonate, paraffin oil, and antioxidant; and / or, The mass ratio of the raw rubber, additives, and fillers is 100:(4-15):(40-150); and / or, The thickness of the compounded rubber sheet is 0.03-0.30 mm; and / or, The surface modification methods of the compound include plasma modification, ozone modification, and ultraviolet light modification.

6. The preparation method according to claim 1, characterized in that, In step S3, the prepreg is selected from at least one of carbon fiber prepreg, aramid fiber prepreg, basalt fiber prepreg, glass fiber prepreg, and ultra-high molecular weight polyethylene fiber prepreg; and / or, The surface modification treatment of the prepreg is plasma treatment, with the following parameters: time 50~600s, power 100~500W.

7. The preparation method according to claim 1, characterized in that, In step S4, the layer ratio of the surface-modified prepreg, the surface-modified compound sheet, and the nanofiber membrane loaded with nanofillers is (4-40):(1-8):(2-39); and / or, The mass ratio of the surface-modified prepreg to the nanofiber membrane loaded with nanofillers is 1:(0.05-0.80); and / or, The preset layer structure is an alternating layer structure, a sandwich layer structure, or a double-layer structure.

8. The preparation method according to claim 1, characterized in that, In step S4, the parameters for hot-press co-curing are: temperature 170~190℃, pressure 1~20 MPa, and holding time 90~120 min.

9. A composite elastic clamp, characterized in that, The composite elastic sandwich panel is prepared by any one of claims 1 to 8, comprising a composite material layer and a rubber layer bonded by co-curing; wherein the composite material layer is formed by co-curing a surface-modified prepreg and a surface-modified nanofiber membrane loaded with nanofillers, and the surface-modified nanofiber membrane loaded with nanofillers is disposed between adjacent surface-modified prepregs. Preferably, the thickness of the composite elastic clamp is 0.5-8.0 mm.

10. The application of the composite elastic clamp as described in claim 9 in suppressing volume expansion during the charging and discharging process of ultra-high energy density lithium battery packs.

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