Method of embedding an electronic device in a filament-wound composite structure

Abstract

A method of embedding an electronic device in a filament-wound composite structure comprises: a) printing a conductive ink trace onto a surface of a first barrier film; b) positioning the electronic device onto the surface of the first barrier film; c) positioning a second barrier film onto the first barrier film to form a dual-layer sandwiched barrier structure, such that the conductive ink trace and the electronic device are encapsulated between the first barrier film and the second barrier film; and d) positioning the dual-layer sandwiched barrier structure between two or more filament-wound composite layers to form the filament-wound composite structure, such that the dual-layer sandwiched barrier structure is encapsulated between said two or more filament-wound composite layers, wherein each of said two or more filament-wound composite layers comprises a plurality of resin-soaked fibers.

Description

[0001] METHOD OF EMBEDDING AN ELECTRONIC DEVICE IN A FILAMENT-WOUND COMPOSITE STRUCTURE

[0002] Field of the Invention

[0003] The present invention relates to the field of advanced composite materials and manufacturing processes, particularly to methods for embedding electronics in fiber-reinforced polymer (FRP) composite structures.

[0004] Background of the Invention

[0005] Fiber-reinforced polymer (FRP) composite materials are widely used in various industries due to their exceptional specific strength and lightweight properties. These advantages make them ideal for applications requiring high performance, such as aerospace, automotive, and civil infrastructure. However, composite structures are typically designed to carry mechanical loads alone, limiting their functionality.

[0006] A growing interest has emerged in transforming composite structures into multifunctional entities, embedding additional capabilities such as sensing, communication, and actuation directly within the structure. By integrating these functionalities, the composite structure evolves beyond its traditional mechanical role, offering enhanced utility and performance.

[0007] Embedded electronic devices within the composite structure are essential for enabling this multifunctionality. Consequently, developing efficient methods for conducting electrical charge within the composite structure is crucial. One promising approach involves using printed electronics to embed conductive lines within or between composite layers during manufacturing.

[0008] This method employs printable conductive inks containing metal particles and chemical agents. These inks can withstand the harsh conditions of the composite manufacturingprocess while maintaining the desired electrical properties in the final product. Initially, the ink is applied in a non-conductive state onto a substrate. It undergoes a sintering process using energy delivery methods such as high-temperature exposure or laser radiation to transform into a conductive state. However, these sintering processes present challenges, including limitations on substrate materials and compatibility with various stages of FRP composite manufacturing.

[0009] While prior work has successfully applied this technology in composite structures manufactured using prepregs (pre-impregnated fibers), challenges remain in extending its applicability to other FRP manufacturing methods, such as filament winding. Filament winding presents unique difficulties due to the state of the resin matrix, which remains liquefied during the manufacturing process, making it unsuitable for direct ink printing.

[0010] Another significant challenge arises when using conducting reinforcement fibers, such as carbon fibers, which are commonly employed in FRP materials. Combined with embedded conductive lines, these fibers can create electrical shorts, complicating the integration of printed electronics into the composite structure.

[0011] Given the challenges mentioned above, an innovative method is needed in the art that enables the seamless integration of printed electronics into FRP composite structures manufactured using filament winding techniques.

[0012] Other objects and advantages of the invention will become apparent as the description proceeds.

[0013] Summary of the Invention

[0014] The present invention provides a method of embedding an electronic device in a filamentwound composite structure.Advantageously, the method accommodates the liquefied resin matrix in filament winding, enabling the embedding of conductive lines and electronic devices without disrupting the resin's state during the process. This ensures that printed electronics can be seamlessly integrated without compromising the manufacturing workflow.

[0015] The method effectively prevents electrical shorts that often occur when conductive reinforcement fibers, such as carbon fibers, are used in conjunction with embedded conductive lines. By mitigating the risk of unintended electrical connections, the method ensures reliable and safe operation of the integrated electronic devices.

[0016] The method increases the flexibility of FRP manufacturing by addressing the specific challenges associated with filament winding and conductive fibers. This allows for printed electronics to be integrated into a wider range of FRP manufacturing processes, offering manufacturers greater versatility in choosing the most suitable method for their applications.

[0017] In conclusion, the method addresses key challenges in filament winding and the integration of conductive reinforcement fibers, enabling the seamless embedding of printed electronics and enhancing both the functionality and versatility of FRP composite structures.

[0018] Brief Description of the Drawings

[0019] In the drawings:

[0020] FIG. 1 is a flowchart of a method of embedding an electronic device in a filament-wound composite structure, according to some embodiments of the invention;

[0021] FIG. 2A is a side-view illustration of a dual-layer sandwiched barrier structure encapsulating a conductive ink trace and an electronic device, according to some embodiments of the invention;FIG. 2B is a side-view illustration of a dual-layer sandwiched barrier structure encapsulated within a filament-wound composite structure, according to some embodiments of the invention;

[0022] FIG. 3A illustrates a dual-layer sandwiched barrier structure enclosing a conductive ink trace and a sensor, according to some embodiments of the invention;

[0023] FIG. 3B illustrates a dual-layer sandwiched barrier structure being placed on a first filamentwound composite layer, according to some embodiments of the invention; and

[0024] FIG. 3C illustrates the application of a second filament-wound composite layer onto the duallayer sandwiched barrier structure and the first filament-wound composite layer using filament winding to form a filament-wound composite structure, according to some embodiments of the invention.

[0025] Detailed Description of the Invention

[0026] The present invention provides a method of embedding an electronic device in a filamentwound composite structure. According to some embodiments, the method involves printing a conductive ink trace onto the surface of a first barrier film using precision printing techniques such as inkjet, aerosol jet, or screen printing. The conductive ink may contain metallic nanoparticles, carbon-based materials, or other conductive compounds. An electronic device is then positioned onto the surface of the first barrier film using additive manufacturing or automated placement techniques, such as inkjet printing or robotic pick-and-place systems. The electronic device may include a sensor, antenna, Light-Emitting Diode (LED), actuator, microchip, battery, wireless communication module, or other suitable electronic components.A second barrier film is positioned over the first barrier film to form a dual-layer sandwiched barrier structure, securely encapsulating the conductive ink trace and the electronic device. These barrier films may be made of polyimide, polyester, polyethylene terephthalate (PET), or fluoropolymers, with thicknesses ranging from 25 pm to 200 pm.

[0027] The dual-layer sandwiched barrier structure is placed between two or more filament-wound composite layers, forming the filament-wound composite structure. The composite layers are made by filament winding resin-soaked fibers onto a winding support structure, such as a mandrel. The dual-layer barrier structure is encapsulated between the composite layers, which may include first and second filament-wound layers. The winding process may involve helical or circumferential patterns, with fibers tensioned to ensure uniformity and minimize voids.

[0028] The filament-wound composite structure is then cured by applying controlled heat and pressure conditions to achieve complete polymerization of the resin. Curing conditions may include temperatures ranging from 120°C to 180°C and pressures from 2 to 15 bars. The curing process also sinters the conductive ink trace, establishing an electrical connection between the trace and the embedded electronic device.

[0029] Advantageously, the method accommodates the liquefied resin matrix in filament winding, enabling the embedding of conductive lines and electronic devices without disrupting the resin's state during the process. This ensures that printed electronics can be seamlessly integrated without compromising the manufacturing workflow.

[0030] The method effectively prevents electrical shorts, which often occur when conductive reinforcement fibers, such as carbon fibers, are used with embedded conductive lines. Bymitigating the risk of unintended electrical connections, the method ensures the reliable and safe operation of the integrated electronic devices.

[0031] The method increases the flexibility of FRP manufacturing by addressing the specific challenges associated with filament winding and conductive fibers. This allows printed electronics to be integrated into a wider range of FRP manufacturing processes, offering manufacturers greater versatility in choosing the most suitable method for their applications.

[0032] Referring to FIGS. 1 and FIGS. 2A-B. FIG. 1 is a flowchart of a method 100 of embedding an electronic device in a filament-wound composite structure, according to some embodiments of the invention. FIG. 2A is a side-view illustration of a dual-layer sandwiched barrier structure 210 encapsulating a conductive ink trace 212 and an electronic device 213, according to some embodiments of the invention. FIG. 2B is a side-view illustration of a dual-layer sandwiched barrier structure 210 encapsulated within a filament-wound composite structure 200, according to some embodiments of the invention.

[0033] At step 110, a conductive ink trace 212 may be printed onto a surface of a first barrier film 211a. Conductive ink trace 212 may be printed onto the surface of first barrier film 211a using a precision printing technique, e.g., inkjet printing, aerosol jet printing, screen printing, gravure printing, flexographic printing, or any suitable precision printing technique. The conductive ink used for conductive ink trace 212 may include metallic nanoparticles, carbonbased materials, or other suitable conductive compounds.

[0034] At step 120, electronic device 213 may be positioned onto the surface of first barrier film 211a. Electronic device 213 may be positioned onto the surface of first barrier film 211a by forming electronic device 213 directly on the surface of first barrier film 211a using an additive manufacturing process, such as inkjet printing, aerosol jet printing, screen printing, or anysuitable additive manufacturing process. Electronic device 213 may be positioned onto the surface of first barrier film 211a using an automated placement system, such as a Robotic Pick-and-Place System or any suitable automated placement system. Electronic device 213 may be a sensor, an antenna, a flexible circuit, a light-emitting diode (LED), an energy harvesting device, an actuator, a conductive component, a microchip, an integrated circuit (IC), a battery, a wireless communication module, a capacitor, a heating element or any electronic device that can be embedded in filament wound composite structures.

[0035] At step 130, a second barrier film 211b may be positioned onto first barrier film 211a to form dual-layer sandwiched barrier structure 210. Second barrier film 211b may be aligned with first barrier film 211a to ensure that conductive ink trace 212 and electronic device 213 are securely encapsulated between first barrier film 211a and second barrier film 211b.

[0036] First barrier film 211a and second barrier film 211b may include films from polyimide (e.g., Kapton), polyester (e.g., mylar), polyethylene terephthalate (pet), fluoropolymer (e.g., PTFE, Teflon), a cured epoxy-based resin, polyvinylidene fluoride (PVDF), silicone-based films, or any suitable film. First barrier film 211a and second barrier film 211b may have thicknesses ranging from 25 pm to 200 pm.

[0037] At step 140, dual-layer sandwiched barrier structure 210 may be positioned between two or more filament-wound composite layers to form filament-wound composite structure 200, such that dual-layer sandwiched barrier structure 210 is encapsulated between the two or more filament-wound composite layers. Each of the two or more filament-wound composite layers may include a plurality of resin-soaked fibers.

[0038] Two or more filament-wound composite layers may include one or more first filament-wound composite layers 220a and one or more second filament-wound composite layers 220b. Dual-layer sandwiched barrier structure 210 may be positioned onto one or more first filamentwound composite layers 220a. One or more first filament-wound composite layers 220a may be disposed on a winding support structure. One or more first filament-wound composite layers 220a may be formed by filament winding a first plurality of resin-soaked fibers onto the winding support structure. The winding support structure may be a mandrel or any suitable support structure for filament winding.

[0039] One or more second filament-wound composite layers 220b may be applied over dual-layer sandwiched barrier structure 210 and one or more first filament-wound composite layers 220a disposed on the winding support structure using filament winding to form filamentwound composite structure 200, such that dual-layer sandwiched barrier structure 210 is encapsulated between one or more first filament-wound composite layers 220a and one or more second filament-wound composite layers 220b. One or more second filament-wound composite layers 220b may include a second plurality of resin-soaked fibers. The second plurality of resin-soaked fibers may be wound over dual-layer sandwiched barrier structure 210 and one or more first filament-wound composite layers 220a disposed on the winding support structure to form filament-wound composite structure 200.

[0040] The filament winding process may involve the continuous or discrete placement of resin-soaked fibers onto the winding support structure (e.g., a mandrel) in a predetermined pattern. The winding support structure may rotate during the filament winding process. The fibers may be tensioned appropriately to ensure uniformity and minimize voids within the composite layers. The winding pattern may include helical, circumferential, cross-winding, or any suitable winding pattern.

[0041] Filament-wound composite structure 200 may be cured to obtain a cured filament-wound composite structure. Filament-wound composite structure 200 may be cured by subjectingfilament-wound composite structure 200 to controlled heat and pressure conditions, ensuring complete polymerization of the resin in filament-wound composite structure 200. For example, subjecting filament-wound composite structure 200 to controlled heat with temperatures ranging from 120 to 180 degrees Celsius and pressure ranging from 2 to 15 bars may ensure complete polymerization of the resin in filament-wound composite structure 200.

[0042] Curing filament-wound composite structure 200 may include simultaneously curing one or more first filament-wound composite layers 220a, one or more second filament-wound composite layers 220b, and dual-layer sandwiched barrier structure 210, such that electronic device 213 is encapsulated and integrated within the cured filament-wound composite structure.

[0043] Curing dual-layer sandwiched barrier structure 210 may sinter conductive ink trace 212 to form a sintered conductive ink trace that establishes an electrical connection between the sintered conductive ink trace and electronic device 213.

[0044] Referring to FIGS. 3A-C. FIG. 3A illustrates a dual-layer sandwiched barrier structure 310 enclosing a conductive ink trace 312 and a sensor 312, according to some embodiments of the invention. FIG. 3B illustrates dual-layer sandwiched barrier structure 310 being placed on a first filament-wound composite layer 320a, according to some embodiments of the invention. FIG. 3C illustrates the application of a second filament-wound composite layer 320b onto duallayer sandwiched barrier structure 310 and first filament-wound composite layer 320 a using filament winding to form a filament-wound composite structure, according to some embodiments of the invention.

[0045] Dual-layer sandwiched barrier structure 310 may be formed using steps 110 to 130 of method 100, as previously described for dual-layer sandwiched barrier structure 210. Dual-layersandwiched barrier structure 310 may be positioned onto first filament-wound composite layer 320a. First filament-wound composite layer 320a may be disposed on a winding support structure 80. First filament-wound composite layer 320a may be formed by filament winding a first plurality of resin-soaked fibers onto winding support structure 80.

[0046] Second filament-wound composite layer 320b may be applied over dual-layer sandwiched barrier structure 310 and first filament-wound composite layer 320a disposed on winding support structure 80 using filament winding to form the filament-wound composite structure, such that dual-layer sandwiched barrier structure 310 is encapsulated between first filamentwound composite layer 320a and second filament-wound composite layer 320b. Second filament-wound composite layer 320b may include a second plurality of resin-soaked fibers. The second plurality of resin-soaked fibers may be wound over dual-layer sandwiched barrier structure 310 and first filament-wound composite layers 320a disposed on winding support structure 80 to form the filament-wound composite structure.

[0047] All the above descriptions and examples have been given for the purpose of illustration and are not intended to limit the invention in any way.

Claims

Claims1) A method of embedding an electronic device in a filament-wound composite structure comprising:a) printing a conductive ink trace onto a surface of a first barrier film;b) positioning the electronic device onto the surface of the first barrier film;c) positioning a second barrier film onto the first barrier film to form a dual-layer sandwiched barrier structure, such that the conductive ink trace and the electronic device are encapsulated between the first barrier film and the second barrier film; andd) positioning the dual-layer sandwiched barrier structure between two or more filament-wound composite layers to form the filament-wound composite structure, such that the dual-layer sandwiched barrier structure is encapsulated between said two or more filament-wound composite layers, wherein each of said two or more filament-wound composite layers comprises a plurality of resin-soaked fibers.2) The method of claim 1, wherein positioning the electronic device onto the surface of the first barrier film comprises forming the electronic device directly on the surface of the first barrier film using an additive manufacturing process.3) The method of claim 1, wherein said two or more filament-wound composite layers comprise one or more first filament-wound composite layers and one or more second filament-wound composite layers.4) The method of claim 3, comprising positioning the dual-layer sandwiched barrier structure onto the one or more first filament-wound composite layers, wherein the one or more first filament-wound composite layers are disposed on a winding support structure and formed by filament winding a first plurality of resin-soaked fibers onto the winding support structure.5) The method of claim 4, comprising applying the one or more second filament-wound composite layers over the dual-layer sandwiched barrier structure and the one or more first filament-wound composite layers using filament winding to form the filamentwound composite structure, such that the dual-layer sandwiched barrier structure is encapsulated between the one or more first filament-wound composite layers and the one or more second filament-wound composite layers.6) The method of claim 5, wherein applying the one or more second filament-wound composite layers over the dual-layer sandwiched barrier structure and the one or morefirst filament-wound composite layers using filament winding comprises winding a second plurality of resin-soaked fibers over the dual-layer sandwiched barrier structure and the one or more first filament-wound composite layers disposed on the winding support structure.7) The method of claim 5, comprising curing the filament-wound composite structure to obtain a cured filament-wound composite structure, wherein curing the filament-wound composite structure comprises simultaneously curing the one or more first filamentwound composite layers, the one or more second filament-wound composite layers, and the dual-layer sandwiched barrier structure, such that the electronic device is encapsulated and integrated within the cured filament-wound composite structure. 8) The method of claim 6, wherein curing the dual-layer sandwiched barrier structure comprises sintering the conductive ink trace to form a sintered conductive ink trace that establishes an electrical connection between the sintered conductive ink trace and the electronic device.9) The method of claim 1, wherein said two or more filament-wound composite layers comprise one or more conductive reinforcement fibers.10) An electronic device embedded in a filament-wound composite structure comprising: a) a first barrier film having a conductive ink trace on a surface thereof;b) an electronic device positioned onto the surface of said first barrier film;c) a second barrier film positioned onto the first barrier film to form a dual-layer sandwiched barrier structure, such that the conductive ink trace and the electronic device are encapsulated between the first barrier film and the second barrier film, said dual-layer sandwiched barrier structure positioned between two or more filament-wound composite layers forming the filament-wound composite structure, such that the dual-layer sandwiched barrier structure is encapsulated between said two or more filament-wound composite layers, wherein each of said two or more filament-wound composite layers comprises a plurality of resin-soaked fibers.11) The device of claim 10, wherein the electronic device is formed directly on the surface of the first barrier film using an additive manufacturing process.12) The device of claim 10, wherein said two or more filament-wound composite layers comprise one or more first filament-wound composite layers and one or more second filament-wound composite layers.13) The device of claim 10, wherein the electronic device is encapsulated and integrated within a cured filament-wound composite structure.14) The device of claim 10, wherein the conductive ink trace is sintered and is in an electrical connection with the electronic device.15) The device of claim 10, wherein said two or more filament-wound composite layers comprise one or more conductive reinforcement fibers.16) The device of claim 10, wherein said two or more filament-wound composite layers are arranged in a helical and / or circumferential winding pattern.

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