Ideal Power Source Research Articles

Influence Mechanism of Electromechanical Parameters on Transient Dynamics of FWD-EVs: Part I: Co-Modeling of IWM and Vehicle System

In-wheel motor (IWM), as an ideal power source of independent four-wheel drive electric vehicles, has been paid more and more attention due to its high-power density, low starting current, wide speed adjustment range, simple control system and robustness. However, the electromechanical issue is enlarged in both longitudinal and vertical because of in-wheel driven scheme. In this paper, the electromagnetic multi-field characteristic of IWM is investigated based on Fourier series method. The negative vibration coupling on vehicle dynamics is discussed by proposing a conjoint electromechanical FWD-EV model. Results shows that the motor incentive coupled with the vehicle system in multi-degree of freedom, caused the body and wheel resonance in the low speed, meanwhile deteriorated the anti-rollover capability of the IWM-EV in the high speed.

A polymer based self-powered ethanol gas sensor to eliminate the interference of ultraviolet light

As a kind of gas sensors, self-powered gas sensor shows significant advantages in large-scale applications such as the internet of things. On the other hand, triboelectric nanogenerator is an ideal power source to fabricate self-powered gas sensor for its high power output and wide variety of driving source. More importantly, it is indispensable to eliminate the influence of environmental factors considering the practical application of gas sensors. In this work, by utilizing the polymer materials with wide bandgap, a polymer based self-powered ethanol gas sensor (PB-SPES) is designed to eliminate the influence of ultraviolet (UV) light in the environment and detect the ethanol gas reliably. Compared with a zinc oxide (ZnO) based self-powered ethanol gas sensor, the PB-SPES shows good stability under UV light illumination.

Fuzzy Logic Controller Application for Automatic Charging System Design of a Solar Powered Mobile Manipulator

Agriculture is a vital industry that affects the livelihoods of many people. Given the reduction in agricultural employees and the increasing strain on farmers, this sector requires convenience, which the automation system may provide. One of the automations is mobile manipulator implementation to substitute farmers. This study investigates the automatic battery charging system supported by the Fuzzy Logic Controller (FLC) to power a mobile manipulator. The application of solar charging is an ideal power source for the robot applied in the open field with high irradiance all year long. This charging system is equipped with IoT monitoring online to monitor the available power produced by solar panel and the battery capacity condition. The effectiveness of the proposed method is proven by experiments conducted for ten times charging in ten days, where the highest power produced by the panel is 1.080 W with 0.563 W charged to the battery. The highest irradiance comes with the highest surface panel temperature of 58.9OC at the irradiance rate of 1021 W/m2. The experimental results show the possibility of the solar-powered robot, which is ideal for agriculture implementation.

Promising Electrode and Electrolyte Materials for High‐Energy‐Density Thin‐Film Lithium Batteries

All‐solid‐state thin‐film lithium batteries (TFLBs) are the ideal wireless power sources for on‐chip micro/nanodevices due to the significant advantages of safety, portability, and integration. As the bottleneck for increasing the energy density of TFLBs, the key components of cathode, electrolyte, and anode are still underway to be improved. In this review, a brief history of TFLBs is first outlined by presenting several TFLB configurations. Based on the state‐of‐the‐art materials developed for lithium‐ion batteries (LIBs), the challenges and related strategies for the application of those potential electrode and electrolyte materials in TFLBs are discussed. Given the advanced manufacture and characterization techniques, the recent advances of TFLBs are reviewed for pursuing the high‐energy‐density and long‐term‐durability demands, which could guide the development of future TFLBs and analogous all‐solid‐state lithium batteries.

Dynamic load distribution of planetary gear sets subject to both internal and external excitations

Planetary gearsets are widely used in several mechanical systems and have numerous advantages over counter-shaft gears. Despite this, the complex arrangement of components in a planetary gear system makes them susceptible to noise and vibration issues. An exhaustive and rich literature is available on the topic of planetary gear dynamics, but most of these studies consider only the parametric excitation of gear mesh contacts while assuming an ideal power source. But contrary to this popular assumption, realistic power sources (IC Engine, electric motor, wind turbine, etc.) could be subjected to torque fluctuations based on the operating conditions. The current study presents a theoretical investigation on the load distribution and dynamic behavior of planetary gear sets subjected to both internal and external excitations. A three-dimensional dynamic planetary load distribution model that inherently captures the internal excitation due to the elastic gear mesh contacts is employed in this study. The influence of operating conditions on both system-level response and local gear mesh contact stress distribution are explored. Discussed results not only illustrate the potential of the dynamic model but also reinforce the need for such computationally efficient models for design and analysis purposes.

Integrating Flexible Ultralight 3D Ni Micromesh Current Collector with NiCo Bimetallic Hydroxide for Smart Hybrid Supercapacitors

AbstractFlexible and lightweight supercapacitors with superior mechanical flexibility and outstanding capacity are regarded as an ideal power source for wearable electronic devices. Meanwhile, incorporating additional novel characters such as transparency and electrochromism can further benefit the development of smart supercapacitors. Nevertheless, the application of the commonly used planar‐structural current collectors is seriously restricted by their intrinsic properties such as poor rigidity, large thickness, and limited loading surface area. Flexible and ultralight current collectors with 3D architecture, high conductivity, and easy integration are believed to be the most appropriate alternatives to build high‐performance supercapacitors. In this study, a novel and scalable manufacturing technique is developed to produce a flexible and ultralight 3D Ni micromesh (3D NM) current collector for supercapacitor. Flexible smart supercapacitor integrated by 3D NM and high active Ni–Co bimetallic hydroxide (3D NM@NiCo BH) delivers a considerable rate performance (60.6% capacity retention from 1 to 50 mA cm−2). Furthermore, the fabricated hybrid supercapacitor device integrated with electrochromic functionality can visually indicate the energy level by a color display. This flexible electrochromic supercapacitor based on ultralight 3D Ni micromesh provides a novel insight into multifunctional energy storage systems for smart wearable electronic devices.

Modeling and Optimal Tuning of Hybrid ESS Supporting Fast Active Power Regulation of Fully Decoupled Wind Power Generators

The frequency stability of the power system is challenged by the high penetration of power electronic interfaced renewable energy sources (RES). This paper investigates the improvements of the frequency response of fully decoupled wind power generators (FDWG) by proposing a novel generic model implementation of ultracapacitors (UC) within a hybrid scheme in real-time simulations of wind power plants. UCs are selected as ideal power sources in fast active power-frequency control due to their high power density and fast-reacting speed. Batteries and UCs combined hybrid energy storage systems (HESS) are formed to complement their characteristics. Droop-based and frequency derivative-based control and virtual synchronous power (VSP) are the selected control strategies to support power system frequency stability. The best trade-off between frequency performance and HESS cost is found by solving a proposed optimization problem formulation. The proposed optimization problem is used to define the HESS size and the controller parameters. The optimization results show how the fast active power-frequency response is enhanced by the fast UC power injection. It also shown that VSP leads to faster frequency support than the droop-based control and the frequency derivative control.

Tunnel Intergrowth Lix MnO2 Nanosheet Arrays as 3D Cathode for High-Performance All-Solid-State Thin Film Lithium Microbatteries.

All-solid-state thin film lithium batteries (TFBs) are proposed as the ideal power sources for microelectronic devices. However, the high-temperature (>500 °C) annealing process of cathode films, such as LiCoO2 and LiMn2 O4, restricts the on-chip integration and potential applications of TFBs. Herein, tunnel structured Lix MnO2 nanosheet arrays are fabricated as 3D cathode for TFBs by a facile electrolyte Li+ ion infusion method at very low temperature of 180 °C. Featuring an interesting tunnel intergrowth structure consisting of alternating 1 × 3 and 1 × 2 tunnels, the Lix MnO2 cathode shows high specific capacity with good structural stability between 2.0 and 4.3 V (vs. Li+ /Li). By utilizing the 3D Lix MnO2 cathode, all-solid-state Lix MnO2 /LiPON/Li TFB (3DLMO-TFB) has been successfully constructed with prominent advantages of greatly enriched cathode/electrolyte interface and shortened Li+ diffusion length in the 3D structure. Consequently, the 3DLMO-TFB device exhibits large specific capacity (185 mAh g-1 at 50 mA g-1 ), good rate performance, and excellent cycle performance (81.3% capacity retention after 1000 cycles), outperforming the TFBs using spinel LiMn2 O4 thin film cathodes fabricated at high temperature. Importantly, the low-temperature preparation of high-performance cathode film enables the fabrication of TFBs on various rigid and flexible substrates, which could greatly expand their potential applications in microelectronics.

Numerical simulation on lean-burn characteristics of a naturally aspirated opposed rotary piston engine fuelled with hydrogen at wide open throttle conditions

Opposed rotary piston engines are characterized by high power density, which makes them as an ideal power source for hybrid vehicles and range extended electric vehicles. Hydrogen applications can fully exhibit the merits of opposed rotary piston engines, and achieve zero carbon dioxide emissions; however, the applications seriously worsen the nitrogen oxides emissions. In this investigation, lean-burn was adopted to achieve low nitrogen oxides emissions using a three dimensional numerical simulation approach. The results indicated that engine speed of 3000 r/min presented the highest in-cylinder pressure during combustion among the given scenarios, and the pressure over 3000 r/min depended more on the equivalence ratio than that of 1000 r/min and 2000 r/min. Heat release rates were very sensitive to low equivalence ratio. Combustion duration over the equivalence ratio of 0.8 was the shortest among 1000 r/min cases; however, it decreased with equivalence ratio for 2000 r/min and 3000 r/min. Heat loss rates through cylinder walls increased significantly with engine speed, meanwhile they were more dependent on the equivalence ratio over higher engine speed. Maximum nitrogen monoxide formation rates over 3000 r/min occurred slightly earlier than those of 1000 r/min and 2000 r/min. Equivalence ratio of 0.8 showed the highest indicated thermal efficiency over corresponding engine speed, and nitrogen dioxide emission factors were quite low over the equivalence ratio of 0.7 for the given engine speed.

Active cyano groups to coordinate AlCl2+ cation for rechargeable aluminum batteries

Rechargeable aluminum batteries, owing to the abundant Al resources and high safety guarantee, have been exploited as the ideal power sources for large-scale energy storage. However, the application of aluminum batteries is still restricted by the unsatisfactory positive electrodes due to low capacity, electrode variation or poor cycle stability of inorganic materials. As an alternative route for addressing the critical issues, multi-cyano organic molecules are proposed as the positive electrode materials for stable rechargeable aluminum batteries. With the first-principle calculation of the electron distribution, molecular energy levels and theoretical specific capacity, the results suggest that the electron-deficient cyano groups in organic molecules can reversibly coordinate/dissociate with positively charged Al-complex ions (i.e. AlCl2+). According to the molecule design and experiment results, tetracyanoquinodimethane (TCNQ) with high conductivity is identified as the optimized cyano-organic positive electrode material. The as-assembled cell delivers a high specific capacity of 180 mAh g−1 at first cycle and a discharge plateau ~1.6 V, along with long-term operation beyond 2000 cycles and coulombic efficiency of ~100%. The design principle here opens a new platform to utilize stable cyano-organic molecules as positive electrode materials for high-energy-density aluminum batteries, offering opportunities to design and exploit high-performance rechargeable Al-organic batteries.

Numerical investigations of combustion and emissions characteristics of a novel small scale opposed rotary piston engine fuelled with hydrogen at wide open throttle and stoichiometric conditions

Popularisations of hybrid vehicles and range extender electric vehicles promote the development of high power density and small scale internal combustion engines. Opposed rotary piston (ORP) engines characterised by compact designs, few moving parts and high power density are an ideal power source for the above mentioned vehicles. Due to the short cyclic period of the ORP engine, hydrogen fuel was applied to decrease the combustion duration. This paper investigated the in-cylinder combustion and emissions characteristics of the hydrogen fuelled ORP engine using 3D numerical simulation method at various engine speeds and full load conditions. In-cylinder pressure evolutions, heat release rates, nitrogen monoxide (NO) formations, and power density were analysed to evaluate the engine performance. The results indicated that volumetric efficiency of this ORP engine was higher than 88.3% for all the given scenarios, being benefited from large area of intake ports. Peak in-cylinder pressure decreased significantly with engine speeds, which was mainly resulted from low fuel mass burn fraction before top dead centre (TDC) for high engine speed conditions. As long as the combustion chambers passed TDC, combustion flame propagated from the bowls into the gaps between end faces of adjacent pistons rapidly. In the exhaust stroke, free discharge process of this ORP engine lasted longer duration than reciprocating engines, which would lead to more energy losses. NO was mainly formed after TDC, with the accumulated NO mass being in the range of 0.07 mg–0.5 mg per cycle per cylinder in the engine speed range of 1000–5000 r/min. Maximum power density and NO emissions factor of this engine fuelled with hydrogen was approximately 69.2 kW·L−1 and 10.60 g·(kW·h)−1, respectively. Indicated thermal efficiency dropped from 36.2% to 26.5% when the engine speed increased from 1000 to 5000 r/min.

Evaluation of the role of nitrogen atoms in cobalt oxynitride electrodes for flexible asymmetric supercapacitors

The use of transition metal oxynitrides as electrode has low cost and high energy density, providing asymmetric supercapacitor devices with an ideal power source. However, the mechanism of inducting foreign nitrogen atoms into transition metal oxides to improve electrochemical performance is unclear. In this work, a transition metal oxynitride layer on flexible carbon cloth (CoON-CC) is presented for the structural design of electrode, which creatively develops an excellent conductivity, numerous active sites and outstanding stability comprising Co3O4 nanorods on flexible carbon cloth electrode (Co3O4-CC). For the first time, a flexible asymmetric supercapacitor (FAS) is prepared with CoON-CC and active carbon electrode (AC-CC) as the positive and negative electrodes, respectively, delivers a high aeral capacitor of and 2.12 F cm−2 (651.5 F g−1) and energy density of 1.17 Wh cm−2 as well as excellent flexibility and cycle performance, outperforming previously reported Co-based asymmetric supercapacitor. Experimental research results and density functional theory calculations reveal that the foreign nitrogen atoms can improve the energetic for redox reaction by modulating the free energy for adsorbed intermediates (OH−, O∗, OOH∗) and also enhance the conductivity, further improving the electrochemical performances of the FAS.

Stamp-assisted flexible graphene-based micro-supercapacitors

The rapid growth of portable and wearable electronics have greatly stimulated simplified fabrication of energy storage devices, from which micro-supercapacitors (MSCs) are an ideal power source, due to high power density and long lifetime. However, the development of a simple and cost-effective procedure towards the fabrication of high-performance MSCs is still a challenge. To this end, here we report a self-patterned stamping process through pre-designed patterns (Fractal & Interdigital) on parafilm® coated polyethylene terephthalate (PET) substrate for the fabrication of a flexible and planar MSC. The imprinted patterns on parafilm® are filled by graphene oxide (GO)/carbon aerogel/MnO2 hybrid paste as a binder and additive-free active material, followed by GO reduction through a safe, low cost, and effective procedure using nascent hydrogen. In contrast to the hydrazine based reduction method, nascent hydrogen affords the integrity and stability to the active material without any peeling off from the substrate, with low ohmic resistance. The prepared MSCs display large capacitance and energy density of 8.7 mF cm−2 (43.66 F cm−3) and 6 mWh cm−3 for Interdigital electrode and 14.2 mF cm−2 (71.34 F cm−3) and 9.9 mWh cm−3 for Fractal electrode, respectively. Furthermore, the MSC displays capacitance retention of 85% after 25,000 cycles. The presented procedure is a simple and cost-effective strategy towards the fabrication of flexible MSCs with state-of-the-art performance.

Hierarchical Mesoporous Iron Fluoride and Reduced Graphene Oxide Nanocomposite as Cathode Materials for High-Performance Sodium-Ion Batteries.

Sodium-ion batteries have been considered as one of ideal power sources for energy storage system. However, the choice of cathode material with good cycling stability and high capacity is limited. Herein, a nanocomposite of hierarchical mesoporous iron fluoride and reduced graphene oxide is prepared by an in situ approach. The as-prepared nanocomposite exhibits remarkably high discharge specific capacity of 227.5 mAh/g at 0.1C. Specifically, the discharge specific capacity of the sample still remains 87.5 mAh/g at a high rate of 15C after the 100th cycle. The electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) measurements show that the addition of reduced graphene oxide can effectively reduce the charge transfer resistance and enhance the Na+ diffusion rate in the FeF3·0.33H2O nanoparticles. The structural changes of FeF3·0.33H2O is further investigated by ex-situ XRD, XPS, and ex situ high-resolution transmission electron microscopy.

On-chip 3D interdigital micro-supercapacitors with ultrahigh areal energy density

The great development of lightweight and portable smart electronic devices has significantly stimulated the interests in exploring and developing miniaturized energy storage systems. High-performance micro-supercapacitors (MSCs) with three-dimensional (3D) nanostructures show a great potential to improve energy storage capability, and these types of MSCs are regarded as ideal stand-alone power sources for smart microelectronics. Here, Cu0.56Co2.44O4@MnO2 core–shell nanoflowers and carbon nanotubes are integrated into a 3D hybrid asymmetric MSC with a fast, convenient, and scalable production fashion. Due to the hierarchical structure of the 3D electrodes and active materials, the hybrid MSC exhibits an improved specific areal capacitance of 665.3 ​mF ​cm−2 at 3.2 ​mA ​cm−2 and an excellent cycling performance of 89.8% retention after 8000 cycles. The MSC also shows an ultrahigh energy density of 182.3 ​μW ​h ​cm−2, which is higher than almost all the previously reported energy density values of on-chip interdigital-electrode MSCs. The efficient fabrication methodology of both the materials and the device demonstrated in this work show great potential in developing high-performance 3D MSCs.

On the possiblity of direct electrical power extraction from scrape-off layer currents in tokamaks

Currents flowing in the scrape-off layer (SOL) are routinely observed in a number of tokamaks. They are usually closed through the divertor plates, either between the inner and outer target or between different poloidal sections of each target. The most common driving mechanisms of SOL currents are the thermoelectric effect (due to electron temperature difference between the two targets) and Pfirsch–Schlüter flows caused by radial pressure gradient. The SOL currents are commonly used for diagnostic purposes—e.g. as ELM monitors or for real-time estimation the divertor electron temperature. In this paper, we report on attempts to extract the SOL currents and related electrical power from the tokamak COMPASS using a dedicated insulated divertor tile and electronics setup, which allows for fast switching between grounded and floating state. It is observed that plasma acts as an ideal power source and that the magnitude of SOL currents scales with upstream separatrix temperature Te,sep.

Analysis of armature inter‐turn fault in the multiphase synchronous generator‐rectifier system

The multiphase synchronous generator-rectifier system could provide an ideal DC power source for more electric aircraft (MEA). When the inter-turn short-circuit fault occurs in phase windings of the generator, a large short-circuit current would be introduced inside the armature windings, which could cause severe damages to the system for overheat in the windings and irons as well as huge electromagnetic forces on the end coils. To improve the reliability of the MEA, this study researches on the inter-turn fault of the multiphase generator-rectifier system including the theoretical analysis, numerical simulation and experiment verification. A 12-phase system is taken, for example, and a multi-loop mathematical model is built up to calculate all voltages and currents in the multiphase synchronous generator-rectifier system with armature inter-turn fault. Many factors are thoroughly considered in the model including the location and short turns of fault, space harmonics of the air-gap magnetic field and the changing circuit topology of the system. Moreover, the mathematical model is verified by fault experiment results. Moreover, the electric characteristics of the fault are summarised, which could provide a quantitative basis for early detection of the inter-turn faults in the multiphase generator-rectifier system.

Polyoxometalate on rice paper derived 3D mesoporous carbon paper: An electrocatalyst as cathode for asymmetric Zn-air battery

Asymmetric Zn-air battery is an ideal power source because of its high voltage and powder density. Acidic active bifunctional oxygen reduction reaction and oxygen evolution reaction electrocatalyst determines the performance of asymmetric Zn-air battery greatly. Here, an efficient bifunctional electrocatalyst is synthesized through the loading of coordination compound modified polyoxometalate on rice paper derived nitrogen doped carbon paper. This elctrocatalyst exhibits three-dimensional network with bulky appearance, which can be employed as air cathode in asymmetric Zn-air battery directly. In acidic electrolyte, it oxygen reduction reaction completes through a typical four-electron process. In oxygen evolution reaction, its overpotential is only 359 mV. With this electrocatalyst as air cathode and Zn plate as anode, an asymmetric Zn-air battery is assembled. The open circuit voltage of this battery is 2.09 V. Its peak power density achieves 349 mW cm−2. When discharge at 20 mA cm−2, its specific energy density reaches 1009 Wh·kg−1. Furthermore, this battery keeps stable in long time charge-discharge experiments. This asymmetric Zn-air battery is superior to traditional Zn-air battery in both charge and discharge process. This work describes an efficient acidic active bifunctional electrocatalyst to construct asymmetric Zn-air battery with high voltage and powder density.

Hydrogen decompression analysis by multi-stage Tesla valves for hydrogen fuel cell

Abstract Hydrogen fuel cell is an ideal power source for electric vehicles. For a hydrogen fuel cell electric vehicle, the hydrogen is reserved in a high pressure level to promote the recharge mileage while relatively low-pressure hydrogen is demanded for proper functioning of the fuel cell stack, so that decompression of hydrogen is needed before hydrogen flowing into the fuel cell. With a reverse flow through Tesla valves, there appears a large pressure drop between the inlet and outlet, which can be used for hydrogen decompression nicely. However, a single-stage Tesla valve cannot meet the pressure drop requirement, so multi-stage Tesla valves are utilized. In this paper, numerical simulations of reversed hydrogen flow through multi-stage Tesla valves are carried out. The stage number of multi-stage Tesla valves and the inlet/outlet pressure ratio are both studied, and the distributions of temperature, pressure, and velocity inside multi-stage Tesla valves are all investigated. Results show that as the stage number increases or the inlet/outlet pressure ratio decreases, the pressure and the velocity inside multi-stage Tesla valves decrease, and the less the stage number, the more possibility for the velocity higher than local acoustic speed. Besides, a power-law relationship between the flow rate, the stage number and pressure ratio is summarized.

Hierarchical Co3O4 Nano-Micro Arrays Featuring Superior Activity as Cathode in a Flexible and Rechargeable Zinc-Air Battery.

All‐solid‐state zinc–air batteries are characterized as low cost and have high energy density, providing wearable devices with an ideal power source. However, the sluggish oxygen reduction and evolution reactions in air cathodes are obstacles to its flexible and rechargeable application. Herein, a strategy called MOF‐on‐MOF (MOF, metal‐organic framework) is presented for the structural design of air cathodes, which creatively develops an efficient oxygen catalyst comprising hierarchical Co3O4 nanoparticles anchored in nitrogen‐doped carbon nano‐micro arrays on flexible carbon cloth (Co3O4@N‐CNMAs/CC). This hierarchical and free‐standing structure design guarantees high catalyst loading on air cathodes with multiple electrocatalytic activity sites, undoubtedly boosting reaction kinetics, and energy density of an all‐solid‐state zinc–air battery. The integrated Co3O4@N‐CNMAs/CC cathode in an all‐solid‐state zinc–air battery exhibits a high open circuit potential of 1.461 V, a high capacity of 815 mAh g−1 Zn at 1 mA cm−2, a high energy density of 1010 Wh kg−1 Zn, excellent cycling stability as well as outstanding mechanical flexibility, significantly outperforming the Pt/C‐based cathode. This work opens a new door for the practical applications of rechargeable zinc–air batteries in wearable electronic devices.