Comprehensive Study on Dynamic Parameters of Symmetric and Asymmetric Ultracapacitors

Electrical storage components such as ultracapacitors (UC) have received significant attention from various industrial sectors, from electric vehicles to renewable power plants. This article presents the investigations on dynamic properties of asymmetric Li-ion hybrid (CPQ2300S: 2300 F, 2.2–3.8 V, JSR Co., Tokyo, Japan) and symmetric double-layer (BCAP3400: 3400 F, 2.85 V, Maxwell Technologies Co., San Diego, CA, USA) ultracapacitors. The internal resistance and capacitance of both UCs were slightly changed with respect to current and voltage alterations, but these changes were more prominent for the Li-ion UC. The internal resistance of the Li-ion UC became five times larger and its capacitance decreased significantly when the temperature decreased from +25 °C to −20 °C. More importantly, the double-layer UC exhibited nearly constant capacitance for a wide range of temperature changes (0 °C to −40 °C), although internal resistance increased somewhat. Electrochemical impedance spectroscopy analysis of both UCs was performed for the frequency range of 1 Hz–1 kHz and in the temperature range from −15 °C to +30 °C. It was observed that the temperature effects were much more pronounced for the asymmetric Li-ion UC than that of the symmetric double-layer UC. This work also proposes an improved equivalent circuit model based on an infinite number of resistance-capacitance (r–C) chains. The characteristic behavior of symmetric UCs can be explained precisely by the proposed model. This model is also applicable to asymmetric UCs, but with less precision.

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Studies on Dynamic Properties of Ultracapacitors Using Infinite r–C Chain Equivalent Circuit and Reverse Fourier Transform

Energies ◽

10.3390/en13184583 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4583

Author(s):

Shailendra Rajput ◽

Alon Kuperman ◽

Asher Yahalom ◽

Moshe Averbukh

Keyword(s):

Mathematical Model ◽

Fourier Transform ◽

Equivalent Circuit ◽

Dynamic Behavior ◽

Double Layer ◽

Electrochemical Impedance ◽

Dynamic Properties ◽

Internal Resistance ◽

Simulation Software ◽

Specific Power

The specific power storage capabilities of double-layer ultracapacitors are receiving significant attention from engineers and scientific researchers. Nevertheless, their dynamic behavior should be studied to improve the performance and for efficient applications in electrical devices. This article presents an infinite resistor–capacitor (r–C) chain-based mathematical model for the analysis of double layer ultracapacitors. The internal resistance and capacitance were measured for repetitive charging and discharging cycles. The magnitudes of internal resistance and capacitance showed approximately ±10% changes for charge-discharge processes. Electrochemical impedance spectroscopy investigations revealed that the impedance of a double-layer ultracapacitor does not change significantly in the temperature range of (−30 °C to +30 °C) and voltage range of (0.3376–2.736 V). The analysis of impedance data using the proposed mathematical model showed good agreement between the experimental and theoretical data. The dynamic behavior of the ultracapacitor was successfully represented by utilizing the proposed infinite r–C chains equivalent circuit, and the reverse Fourier transform analysis. The r–C electrical equivalent circuit was also analyzed using the PSIM simulation software to study the dynamic behavior of ultracapacitor parameters. The simulation study yields an excellent agreement between the experimental and calculated voltage characteristics for repetitive charging-discharging processes.

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Unification of Internal Resistance Estimation Methods for Li-Ion Batteries Using Hysteresis-Free Equivalent Circuit Models

Batteries ◽

10.3390/batteries6020032 ◽

2020 ◽

Vol 6 (2) ◽

pp. 32

Author(s):

S M Rakiul Islam ◽

Sung-Yeul Park ◽

Balakumar Balasingam

Keyword(s):

Parameter Estimation ◽

Equivalent Circuit ◽

Electrochemical Impedance ◽

Estimation Method ◽

Equivalent Circuit Model ◽

Parameter Extraction ◽

Internal Resistance ◽

Least Square ◽

Estimation Methods ◽

Li Ion

Internal resistance is one of the important parameters in the Li-Ion battery. This paper identifies it using two different methods: electrochemical impedance spectroscopy (EIS) and parameter estimation based on equivalent circuit model (ECM). Comparing internal resistance, the conventional parameter estimation method yields a different value than EIS. Therefore, a hysteresis-free parameter identification method based on ECM is proposed. The proposed technique separates hysteresis resistance from the effective resistance. It precisely estimated actual internal resistance, which matches the internal resistance obtained from EIS. In addition, state of charge, open circuit voltage, and different internal equivalent circuit components were identified. The least square method was used to identify the parameters based on ECM. A parameter extraction algorithm to interpret impedance spectrum obtained from the EIS. The algorithm is based on the properties of Nyquist plot, phasor algebra, and resonances. Experiments were conducted using a cellphone pouch battery and a cylindrical 18650 battery.

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Operational and financial performance of fossil fuel power plants within a high renewable energy mix

10.22261/2bioto ◽

2017 ◽

Vol 1 ◽

pp. 2BIOTO ◽

Cited By ~ 7

Author(s):

Patrick Eser ◽

Ndaona Chokani ◽

Reza S. Abhari

Keyword(s):

Renewable Energy ◽

Financial Performance ◽

Electricity Markets ◽

Power Plants ◽

Energy System ◽

Renewable Power ◽

High Penetration ◽

Demand Models ◽

Wide Range ◽

Coal Power Plants

AbstractThe operation of conventional power plants in the 2030 high-renewable energy system of central Europe with high penetration of renewables is simulated in this work. Novel insights are gained in this work, since the generation, transmission and demand models have high geographic resolution, down to scale of individual units, with hourly temporal resolution. It is shown that the increases in the partload efficiency that optimize gas power plants’ financial performance in 2030 are highly dependent on the variability in power production of renewable power plants that are in close proximity to the gas power plants. While coal power plants are also cycled more, an increased baseload efficiency is more beneficial for their financial viability. Thus, there is a need for OEMs to offer a wide range of technology solutions to cover all customers’ needs in electricity markets with high penetrations of renewables. Therefore there is an increased investment risk for OEMs as they strive to match their customers’ future needs.

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Broadband Impedance Measurement of Lithium-Ion Battery in the Presence of Nonlinear Distortions

Energies ◽

10.3390/en13102493 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2493

Author(s):

Jussi Sihvo ◽

Tomi Roinila ◽

Daniel-Ioan Stroe

Keyword(s):

Electrochemical Impedance ◽

Equivalent Circuit Model ◽

Impedance Measurement ◽

Lithium Ion ◽

Li Ion Battery ◽

Third Order ◽

Impedance Measurements ◽

Nonlinear Distortions ◽

Measured Impedance ◽

Li Ion

The impedance of a Lithium-ion (Li-ion) battery has been shown to be a valuable tool in evaluating the battery characteristics such as the state-of-charge (SOC) and state-of-health (SOH). Recent studies have shown impedance-measurement methods based on broadband pseudo-random sequences (PRS) and Fourier techniques. The methods can be efficiently applied in real-time applications where the conventional electrochemical-impedance spectroscopy (EIS) is not well suited to measure the impedance. The techniques based on the PRS are, however, strongly affected by the battery nonlinearities. This paper presents the use of a direct-synthesis ternary (DST) signal to minimize the effect caused by the nonlinearities. In such a signal, the second- and third-order harmonics are suppressed from the signal energy spectrum. As a result, the effect of the second- and third-order nonlinearities are suppressed from the impedance measurements. The impedance measurements are carried out for a nickel manganese cobalt Li-ion battery cell. The performance of the method is compared to the conventional EIS, as well as to other PRS signals which are more prone to battery nonlinearities. The Kronig–Kramers (K–K) transformation test is used to validate the uniqueness of the measured impedance spectra. It is shown that the measurement method based on the DST produces highly accurate impedance measurements under nonlinear distortions of the battery. The method shows a good K–K test behavior indicating that the measured impedance complies well to a linearized equivalent circuit model that can be used for the SOC and SOH estimation of the battery. Due to the good performance, low measurement time, and simplicity of the DST, the method is well suited for practical battery applications.

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Geothermal energy in Germany

Energy Safety and Energy Economy ◽

10.18635/2071-2219-2020-6-18-23 ◽

2020 ◽

Vol 6 ◽

pp. 18-23

Author(s):

Vitaly Butuzov

Keyword(s):

Heat Exchanger ◽

Electric Power ◽

Geothermal Energy ◽

Power Plants ◽

Geothermal Systems ◽

Paper Briefly ◽

Renewable Power ◽

Binary Cycle ◽

Wide Range ◽

Double Wells

Geothermal energy is a significant source of renewable power. In Germany, geothermal technology incorporates a wide range of solutions as shown in this paper. Briefly, this technology is generally based on geothermal loop systems with double wells. There are also five well heat exchanger geothermal systems and two shaft water geothermal systems operating in Germany. Eleven geothermal power plants of 21.8 MW in sum are binary cycle operated and using coolants. Four of them generate electric power while seven cogenerate electric power and heat.

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BENDING DETECTION OF LI-ION POUCH CELLS USING IMPEDANCE SPECTRA

ASME Letters in Dynamic Systems and Control ◽

10.1115/1.4049527 ◽

2021 ◽

pp. 1-6

Author(s):

Mohsen Derakhshan ◽

Mehdi Gilaki ◽

Andrew Stacy ◽

Elham Sahraei ◽

Damoon Soudbakhsh

Keyword(s):

Electrochemical Impedance ◽

Equivalent Circuit Model ◽

Mechanical Damage ◽

Form Factors ◽

Control Group ◽

Model Parameters ◽

Impedance Spectra ◽

Bending Load ◽

Li Ion ◽

Constant Phase Elements

Abstract Li-ion batteries are the preferred choice of energy storage in many applications. However, the potential for fire and explosion due to mechanical damage remains a safety concern. Currently, there are no criteria for the extent of the mechanical damage under which the batteries are safe to use. Here, we investigate the effects of bending damage to Li-ion cells on their impedance spectra. After the initial characterization of four Li-ion pouch cells, one of the cells underwent a three-point bending load. We measured the impedance spectra of this cell after each increment of loading. The impedance data of the control group cells were collected at the same intervals as the damaged cell. A distributed equivalent circuit model (dECM) was developed using the data from the electrochemical impedance spectroscopy (EIS) procedure. We observed that several model parameters such as the magnitude of constant phase elements had similar trends in the control cells and the bent cell. However, some model parameters such as resistances in parallel with constant phase elements, and the inductor showed dependency on the extent of the damage. These results suggest the potential for use of such parameters as an indicator of mechanical damage when visual inspection of cells is not possible in a battery pack setup. Future steps include investigation of similar trends for other commercial batteries,chemistries, and form factors to verify the applicability of the current findings in a broader context.

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Combustion of Biomass Based Pellets With Pyrolysis Bio-Oils

Volume 6: Energy ◽

10.1115/imece2019-11593 ◽

2019 ◽

Author(s):

Diogo Manuel Couto ◽

Maria Margarida Gonçalves ◽

Joana Carvalho ◽

Manuel Eduardo Ferreira ◽

Jorge Araújo ◽

...

Keyword(s):

Power Plants ◽

Raw Materials ◽

Organic Liquid ◽

Primary Source ◽

Industrial Wastes ◽

Wood Pellets ◽

Saw Dust ◽

Industrial Sectors ◽

Wide Range ◽

Bio Oil

Abstract Due to increased energy demands and environmental concerns, biomass has become an increasingly attractive primary source in the energy mix. It can be used as heat supply to both domestic and industrial sectors, but also as fuel in dedicated or co-generation-based power plants and it is also considered CO2 neutral. Amongst the most widely used formats, wood pellets are very attractive because of their standardized properties which makes them efficient over a wide range of applications. In Portugal alone, over 1 million tons a year are produced. However, due to their attractiveness, the pressure on traditional raw materials for their fabrication (saw dust) has driven the cost upwards and induced bottlenecks upstream in the supply chain. One way to expand the range of raw materials is to combine a biomass based matrix with alien materials into the same pellet format. In this way one can also find alternative uses for other materials which, some of them wastes, are often dumped into landfills. Such an approach has been pursued into combining industrial wastes with biomass in pellets. This project concerns the evaluation of the combustion behavior of saw dust based pellets fortified with pyrolysis bio-oils produced from waste vegetable oils. The bio-oil is an organic liquid obtained by pyrolysis of used vegetable sunflower oil, at 420 °C and 10 min. The pellets were manufactured with pine saw dust with bio-oil incorporation up to 5% in mass. The resulting pellets were fully characterized for their properties, including the heating value, which increased when compared with standard saw dust pellets. These pellets were afterward tested in a fully instrumented 20 kW fixed grate combustion facility. The flue gases were analyzed and the resulting ashes were tested for their chemical composition in order to assess their ability to melt during combustion. The results show that this route can be beneficial in terms of exhaust emissions, including promoting the reduction of NOx during combustion. However, the physical characteristics of the pellets have some restrictions, since they do not meet minimum requirements for its certification ENplus level of density, mechanical durability and fines content.

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Concepts of Emission Reduction in Fluidized Bed Combustion of Biomass

Acta Polytechnica ◽

10.14311/1610 ◽

2012 ◽

Vol 52 (4) ◽

Author(s):

Amon Purgar ◽

Franz Winter

Keyword(s):

Fluidized Bed ◽

Emission Reduction ◽

Power Plants ◽

International Energy Agency ◽

Waste To Energy ◽

Status Report ◽

Low Grade ◽

Fluidized Bed Combustion ◽

Industrial Sectors ◽

Wide Range

A status report on fluidized bed technology in Austria is under preparation, in response to the Fluidized Bed Conversion multi-lateral technology initiative of the International Energy Agency. This status report focuses on the current operation of fluidized bed combustors. Combustors have been installed in the following industrial sectors: pulp and paper, biomass heat and power plants, waste-to-energy plants, and communal sewage sludge treatment plants. There are also some small demonstration plants. These plants all have in common that they treat renewable fuel types. In many cases, only bio-fuels are treated. Besides the ability to burn a wide range of low-grade and difficult fuels, fluidized bed combustors have the advantages of low NOX emissions and the possibility of in-process capture of SO2. Various emission reduction concepts for fluidized bed combustors that are typical for their industrial sector are discussed. The discussion of these concepts focuses on NOX, SO2 and dust.

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Guidelines for the Characterization of the Internal Impedance of Lithium-Ion Batteries in PHM Algorithms

International Journal of Prognostics and Health Management ◽

10.36001/ijphm.2018.v9i3.2746 ◽

2020 ◽

Vol 9 (3) ◽

Author(s):

Aramis Pérez ◽

Matias Benavides ◽

Heraldo Rozas ◽

Sebastián Seria ◽

Marcos Orchard

Keyword(s):

Electrochemical Impedance ◽

Equivalent Circuit Model ◽

Lithium Ion ◽

Dynamic Parameter ◽

Li Ion Batteries ◽

Li Ion Battery ◽

Internal Impedance ◽

Battery Degradation ◽

Li Ion

This article aims to describe the most important aspects to consider when using the concept of internal impedance in algorithms that focus on characterizing the degradation of lithium-ion (Li-ion) batteries. The first part of the article provides a literature review that will help the reader understand the concept of electrochemical impedance spectroscopy (EIS) and how Li-ion batteries can be represented through electrochemical or empirical models, in order to interpret the outcome of typical discharge and/or degradation tests on Li-ion batteries. The second part of the manuscript shows the obtained results of an accelerated degradation experiment performed under controlled conditions on a Li-ion cell. Results show that changes observed on the EIS test can be linked to battery degradation. This knowledge may be of great value when implementing algorithms aimed to predict the End-of-Life (EoL) of the battery in terms of temperature, voltage, and discharge current measurements. The purpose of this article is to introduce the reader to several types of Li-ion battery models, and show how the internal impedance of a Li-ion battery is a dynamic parameter that depends on different factors; and then, illustrate how the EIS can be used to obtain an equivalent circuit model and how the different electronic components vary with the use given to the battery.

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Development and Experimental Validation of a Supercapacitor Frequency Domain Model for Industrial Energy Applications Considering Dynamic Behaviour at High Frequencies

Energies ◽

10.3390/en13051156 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1156 ◽

Cited By ~ 2

Author(s):

Gustavo Navarro ◽

Jorge Nájera ◽

Jorge Torres ◽

Marcos Blanco ◽

Miguel Santos ◽

...

Keyword(s):

Energy Storage ◽

High Frequency ◽

Electrochemical Impedance ◽

Storage System ◽

Electric Circuit ◽

Experimental Tests ◽

Internal Resistance ◽

Industrial Applications ◽

Domain Model ◽

Wide Range

Supercapacitors, one of the most promising energy storage technologies for high power density industrial applications, exchange the energy mostly through power electronic converters, operating under high frequency components due to the commutation. The high frequency produces important effects on the performance of the supercapacitors in relation to their capacitance, inductance and internal resistance (ESR). These parameters are fundamental to evaluate the efficiency of this energy storage system. The aim of the paper is to obtain an accurate model of two supercapacitors connected in series (functional and extrapolated unit) to represent the frequency effects for a wide range of frequencies. The methodology is based on the definition of an appropriate equivalent electric circuit with voltage dependance, obtaining their parameters from experimental tests, carried out by means of electrochemical impedance spectroscopy (EIS) and the use of specific software tools such as EC-Lab® and Statgraphics Centurion®. The paper concludes with a model which reproduces with accuracy both the frequency response of the model BCAP3000 supercapacitors, provided by the manufacturer, and the experimental results obtained by the authors.

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