Study of Energy Harvesting Performance of Wet-Stretched PVDF Nanofibers

2016 ◽  
Author(s):  
Raghid Najjar ◽  
Yi Luo ◽  
Xiao Hu ◽  
Vince Beachley ◽  
Wei Xue
Keyword(s):  
Energy Harvesting ◽  
Polyvinylidene Fluoride ◽  
Low Cost ◽  
Mechanical Energy ◽  
Body Movement ◽  
Electrical Energy ◽  
Electrospinning Process ◽  
Energy Harvesters ◽  
Portable Electronics ◽  
Wearable Systems

An average human body produces a large amount of energy throughout the day. A significant portion of this energy is utilized as mechanical energy. Body movement such as footfalls and arm swings can produce enough energy to power portable electronics using mechanical-to-electrical energy harvesters. These devices should be small, light, portable, and flexible. Polyvinylidene fluoride (PVDF) has shown a high biocompatibility and is a suitable candidate for energy harvesting applications. Moreover, PVDF can be produced in large quantities while still maintaining a low cost. Electrospinning is a common process used to prepare PVDF nanofibers. Here we introduce a novel technique called wet-stretched electrospinning to further increase the amount of energy generated by the PVDF devices. Our initial results show that the wet-stretched nanofibers outperform the regular PVDF nanofibers by up to 12 times under similar conditions. These promising results suggest that the proposed method has great potential to be utilized as a major improvement from the traditional electrospinning process of PVDF. These findings are significant and are especially pertinent to the field of energy harvesters designed for powering medical devices or wearable systems.

Comparative Studies of Wet-Stretched and Non-Stretched Electrospun PVDF-HFP Nanofibers

2017 ◽  
Author(s):  
Alexander Wildgoose ◽  
Raghid Najjar ◽  
Jason Dittman ◽  
Harrison Hones ◽  
Emily Umbach ◽  
...  
Keyword(s):  
Alternative Energy ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Body Movement ◽  
Electrospun Nanofibers ◽  
Electrospinning Technique ◽  
Fiber Network ◽  
Energy Harvesters ◽  
Portable Electronics ◽  
Alternative Energy Sources

The recent growth in portable electronics has sparked a demand for alternative energy sources. Energy harvesters that utilize piezoelectric materials are promising in capturing the mechanical energy from body movement to power portable electronics. This study investigated the characteristics of PVDF-HFP nanofibers created from traditional electrospinning and a novel technique called wet-stretching electrospinning. The solution was initially processed using the traditional method, flat-plate electrospinning, which resulted in a fiber network with random orientations. When performing electrical testing the fibers produced minimal voltage. The solution was then processed utilizing a novel wet-stretching electrospinning technique that allowed for fiber alignment and dynamic stretch ratios. Fibers that underwent this method produced higher voltages than fibers from the traditional electrospinning method. It was observed that fibers processed using the wet-stretching technique with different draw ratios (DR) such as 1 (DR 1) and 2.5 (DR 2.5) showed enhanced piezoelectric properties. This research suggests that the wet-stretched PVDF-HFP nanofibers are better suited for piezoelectric applications than traditionally electrospun nanofibers.

Modeling and analysis of the effect of substrate on the flexible piezoelectric films for kinetic energy harvesting from textiles

2018 ◽  
Vol 53 (24) ◽  
pp. 3349-3361 ◽  
Author(s):  
Nabil Chakhchaoui ◽  
H Jaouani ◽  
H Ennamiri ◽  
A Eddiai ◽  
A Hajjaji ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Piezoelectric Material ◽  
Polyvinylidene Fluoride ◽  
Mechanical Energy ◽  
Excitation Frequency ◽  
Electrical Energy ◽  
Structure Type ◽  
Smart Structure ◽  
Resistive Load ◽  
Woven Textile

In the last few years, a lot of research focused on increasing of smart textiles products such as woven and knitted structures, which are able to show significant change in their mechanical properties (such as shape and stiffness), in a practical way in response to the stimuli. In this paper, we investigate the potential of a flexible piezoelectric film stuck onto three woven textile matrices: cotton, polyester/cotton, and Kermel, for harvesting mechanical energy from the textile and converting it into electrical energy. At first, a brief introduction of energy harvesting using the piezoelectric material and smart textile is presented. Furthermore, a basic model showing the operation of polyvinylidene fluoride with 33 mode is established. The second part is focused on standard approach model of energy harvesting based on resistive load and freestanding piezo-polymer for the examination of the performance of 33-mode polyvinylidene fluoride energy harvester and the prediction of harvested energy quantity. A power analytical model generated by a smart structure type polyvinylidene fluoride that can be stuck onto fabrics and flexible substrates is investigated. On the other hand, the effects of various substrates and the sticking of these substrates on the piezoelectric material are reported. Additionally, the output power density of this theoretical model of woven textile matrices could reach a value that was seven times higher than freestanding piezo-polymer. Three types of the substrates have been compared as function of excitation frequency and the compressive applied force.

Preparation of Polyvinylidene Fluoride (PVDF) Triboelectric Nanogenerators with Different Polymer

2015 ◽  
Vol 814 ◽  
pp. 91-95
Author(s):  
Cheng Wang ◽  
Hao Yu ◽  
Tao Huang ◽  
Chao Tan
Keyword(s):  
Polymer Films ◽  
Polyvinylidene Fluoride ◽  
Low Cost ◽  
Mechanical Energy ◽  
Flexible Polymer ◽  
Surrounding Environment ◽  
Nanofiber Membranes ◽  
External Consistency ◽  
Low Wear ◽  
Triboelectric Nanogenerators

Triboelectric nanogenerators have recently been used to harvest mechanical energy from surrounding environment which is of great significance in the field of energy conversion. Electrospinning provides a simple, low cost and versatile method for the generation of 1D nanostrucutures. Nanofiber membranes have many advantages over the commonly used dense film for designing the riboelectric nanogenerators, such as the low wear resistance caused from the internal and excellent external consistency of the electrospinning membranes. In this paper, we produce a variety of polymer films by electro-spinning, and fabricate Polyvinylidene Fluoride (PVDF) triboelectric nanogenerators with different polymer films afterwards. We except to explore the TEG power generation effect, and influencing factors, and then determine the best combination of the results of TEG (PVDF-PHBV). Such a flexible polymer TEG generates output voltage of up to 112 V at a power of 0.045W.

Energy harvesting from quasi-static deformations via bilaterally constrained strips

2018 ◽  
Vol 29 (18) ◽  
pp. 3572-3581
Author(s):  
Suihan Liu ◽  
Ali Imani Azad ◽  
Rigoberto Burgueño
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Energy Resource ◽  
Electrical Energy ◽  
Piezoelectric Energy Harvesting ◽  
Power Budget ◽  
Piezoelectric Energy ◽  
Static Conditions

Piezoelectric energy harvesting from ambient vibrations is well studied, but harvesting from quasi-static responses is not yet fully explored. The lack of attention is because quasi-static actions are much slower than the resonance frequency of piezoelectric oscillators to achieve optimal outputs; however, they can be a common mechanical energy resource: from large civil structure deformations to biomechanical motions. The recent advances in bio-micro-electro-mechanical systems and wireless sensor technologies are motivating the study of piezoelectric energy harvesting from quasi-static conditions for low-power budget devices. This article presents a new approach of using quasi-static deformations to generate electrical power through an axially compressed bilaterally constrained strip with an attached piezoelectric layer. A theoretical model was developed to predict the strain distribution of the strip’s buckled configuration for calculating the electrical energy generation. Results from an experimental investigation and finite element simulations are in good agreement with the theoretical study. Test results from a prototyped device showed that a peak output power of 1.33 μW/cm2 was generated, which can adequately provide power supply for low-power budget devices. And a parametric study was also conducted to provide design guidance on selecting the dimensions of a device based on the external embedding structure.

scholarly journals Hollow Piezoelectric Ceramic Fibers for Energy Harvesting Fabrics

2013 ◽  
Vol 8 (1) ◽  
pp. 155892501300800
Author(s):  
François M. Guillot ◽  
Haskell W. Beckham ◽  
Johannes Leisen
Keyword(s):  
Energy Harvesting ◽  
Lead Zirconate Titanate ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Lead Zirconate ◽  
Ceramic Fibers ◽  
Power Sources ◽  
Electromechanical Performance ◽  
Alternative Power

In the past few years, the growing need for alternative power sources has generated considerable interest in the field of energy harvesting. A particularly exciting possibility within that field is the development of fabrics capable of harnessing mechanical energy and delivering electrical power to sensors and wearable devices. This study presents an evaluation of the electromechanical performance of hollow lead zirconate titanate (PZT) fibers as the basis for the construction of such fabrics. The fibers feature individual polymer claddings surrounding electrodes directly deposited onto both inside and outside ceramic surfaces. This configuration optimizes the amount of electrical energy available by placing the electrodes in direct contact with the surface of the material and by maximizing the active piezoelectric volume. Hollow fibers were electroded, encapsulated in a polymer cladding, poled and characterized in terms of their electromechanical properties. They were then glued to a vibrating cantilever beam equipped with a strain gauge, and their energy harvesting performance was measured. It was found that the fibers generated twice as much energy density as commercial state-of-the-art flexible composite sensors. Finally, the influence of the polymer cladding on the strain transmission to the fiber was evaluated. These fibers have the potential to be woven into fabrics that could harvest mechanical energy from the environment and could eventually be integrated into clothing.

Dielectric Elastomer Energy Harvesting and its Application to Human Walking

2011 ◽  
Author(s):  
Heather Lai ◽  
Chin An Tan ◽  
Yong Xu
Keyword(s):  
Energy Harvesting ◽  
Knee Joint ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
High Energy ◽  
Dielectric Elastomer ◽  
Metabolic Energy ◽  
High Energy Density ◽  
Human Walking ◽  
Wide Range

Human walking requires sophisticated coordination of muscles, tendons, and ligaments working together to provide a constantly changing combination of force, stiffness and damping. In particular, the human knee joint acts as a variable damper, dissipating greater amounts of energy when the knee undergoes large rotational displacements during walking, running or hopping. Typically, this damping results from the dissipation, or loss, of metabolic energy. It has been proven to be possible however; to collect this otherwise wasted energy through the use of electromechanical transducers of several different types which convert mechanical energy to electrical energy. When properly controlled, this type of device not only provides desirable structural damping effects, but the energy generated can be stored for use in a wide range of applications. A novel approach to an energy harvesting knee joint damper is presented using a dielectric elastomer (DE) smart material based electromechanical transducer. Dielectric elastomers are extremely elastic materials with high electrical permittivity which operate based on electrostatic effects. By placing compliant electrodes on either side of a dielectric elastomer film, a specialized capacitor is created, which couples mechanical and electrical energy using induced electrostatic stresses. Dielectric elastomer energy harvesting devices not only have a high energy density, but the material properties are similar to that of human tissue, making it highly suitable for wearable applications. A theoretical framework for dielectric elastomer energy harvesting is presented along with a mapping of the active phases of the energy harvesting to the appropriate phases of the walking stride. Experimental results demonstrating the energy harvesting capability of a DE generator undergoing strains similar to those experienced during walking are provided for the purpose of verifying the theoretical results. The work presented here can be applied to devices for use in rehabilitation of patients with muscular dysfunction and transfemoral prosthesis as well as energy generation for able-bodied wearers.

Resonant Frequency Tuning Strategies for Vibration-Based Energy Harvesters

2017 ◽  
Author(s):  
Lin Dong ◽  
Frank T. Fisher
Keyword(s):  
Energy Harvesting ◽  
Resonant Frequency ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Electrical Energy ◽  
Mechanical Stretch ◽  
Applied Bias Voltage ◽  
Energy Harvesters ◽  
Frequency Matching ◽  
Low Levels

Vibration-based energy harvesting has been widely investigated to as a means to generate low levels of electrical energy for applications such as wireless sensor networks. However, due to the fact that vibration from the environment is typically random and varies with different magnitudes and frequencies, it is a challenge to implement frequency matching in order to maximize the power output of the energy harvester with a wider frequency bandwidth for applications where there is a time-dependent, varying source frequency. Possible solutions of frequency matching include widening the bandwidth of the energy harvesters themselves in order to implement frequency matching and to perform resonance-based tuning approach, the latter of which shows the most promise to implement a frequency matching design. Here three tuning strategies are discussed. First a two-dimensional resonant frequency tuning technique for the cantilever-geometry energy harvesting device which extended previous 1D tuning approaches was developed. This 2D approach could be used in applications where space constraints impact the available design space of the energy harvester. In addition, two novel resonant frequency tuning approaches (tuning via mechanical stretch and tuning via applied bias voltage, respectively) for electroactive polymer (EAP) membrane-based geometry energy harvesters was proposed, such that the resulting changes in membrane tension were used to tune the device for applications targeting variable ambient frequency environments.

Stress Analysis of Smart Beam Energy Harvesters

2016 ◽  
Author(s):  
Nathan S. Hosking ◽  
Zahra Sotoudeh
Keyword(s):  
Smart Materials ◽  
Mechanical Energy ◽  
Strain Analysis ◽  
Electrical Energy ◽  
Structural Dynamic ◽  
Energy Harvesters ◽  
Beam Equations ◽  
Variational Asymptotic ◽  
Strain Components ◽  
Smart Beam

In this paper, we study fully coupled electromagnetic-elastic behaviors present in the structures of smart beams using variational asymptotic beam sections and geometrically exact fully intrinsic beam equations combined in a consistent theory. We present results for smart beams under various oscillatory loads in both the axial and transverse directions and calculate the corresponding deformations. Recovery equations are employed to construct the full 3D stress and strain components in order to complete a full stress / strain analysis. Smart materials change mechanical energy to electrical energy; therefore, changing the structural dynamic behavior of the structure and its stiffness matrix.

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