DOCSLIB.ORG

Electricity on Demand

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electricity on Demand Photovoltaics energy storage t takes neither a science fiction fan nor a clairvoy- ant to launch the theory that electricity will be the Ideterminant energy form of the future. It is simply the most logical development. Electricity can be used safely and efficiently in all manner of applications, and – when generated from a renewable source – is also clean energy. But electricity does have one decisive disadvan- tage: it must be consumed immediately – storage has to date remained both complex and subject to expen- sive losses. The limited capacity of storage batteries, for example, is the chief obstacle to the widespread breakthrough of electric cars, a path of development with the potential to solve a massive share of the glo- bal CO2 problem. When oil tanks or coal bunkers are taken as the yardsticks for the energy density, cost ef- fectiveness and useful lifetime of electricity storage technologies, it becomes painfully evident: the stor- age problem is yet to be solved for electricity. This fact naturally has direct repercussions for the photovoltaics sector with its dependence on sun- light as a primary energy source. When the European PV industry claims that it is prepared to cover half of the continent’s power demand with solar electricity by 2050, then this must necessarily be described as ambitious. It will require not only reliable supplies of materials, sufficient investment capital and adequate manufacturing capacities, but also a solution to the storage problem – and that well before 2050. Many circumstances can be covered by the power supply systems in the industrialised countries, but one op- tion is very definitely unacceptable, namely that half of the generating capacity simply goes off-grid when darkness falls. If electricity is to be generated from re- newable sources on a larger scale, then it must also be possible to store it. Of the renewable energies cur- rently under discussion, only biogas seems suitable as a baseload source. Wind and solar energy, by con- trast, are subject to marked fluctuation: you may get the full nominal output, or nothing at all – depending Decentralised and fluctuating power generation from the sun and wind is becoming on the momentary irradiation or wind intensity. more and more widespread. The expansion of power grids is thus important – but still not sufficient. Storage capacities are imperative. Photos (2): E.on Netz Diverse approaches Various, in some cases quite exotic projects are aimed at overcoming today’s expensive and cumber- some battery concepts. In 2007, there were press re- Electricity on ports that Sony is working on a bio-battery which functions on the principle of photosynthesis. A year ago, news spread concerning experiments aimed at developing a bio-battery at the University of Colora- do. The idea: cells pump ions through a membrane demand and produce a potential difference which can be ex- ploited. It is similarly two years since the scientific There are certain technology challenges which have waited journal “Technology Review” reported on a battery prototype devised at the Japanese elite university in vain over several decades for a satisfactory solution. The Waseda. It is less than a millimetre thick, can be fully economical storage of electricity is one of them. But charged in just one minute and is said to handle 1,000 charging cycles. The positive electrode of the intensive work in the meantime is driving advances along battery is made not from a metallic compound, but in- stead from polymers. The cathode film forms only af- various avenues . ter the precursor material is subjected to UV radia- 108 Sun & Wind Energy 4/2009 tion. According to “Technology Review”, the perfor- The first commercial availability is expected for 2009, mance data of the battery are satisfactory: 0.84 volts but there are only two manufacturers worldwide. and a specific capacity of 106 mAh. The journal has also described a flexible battery in connection with Vanadium redox flow battery: This battery type func- the European solar polymer battery project: this bat- tions with salts dissolved in a liquid electrolyte. The tery comprises further-developed lithium ion batte- electrolyte is held in separate tanks and is only ries which are charged via an integrated dye solar pumped to the electrodes and the membrane in the cell. The battery is extremely thin and light, and with- central reaction cell when necessary. The vanadium stands also high temperatures. But several more redox flow battery is just one of a number of material years can be expected to pass before these new con- variants, but “is still the only one which functions”, cepts are ready for practical applications. says Dirk Uwe Sauer, Professor and storage expert at the RWTH University in Aachen, Germany. This points Common battery concepts to interesting cost-reducing potential, because vana- dium, after all, is expensive. The batteries impress by For the time being, we must continue to make do with way of a long lifetime and their insensitivity to deep the familiar electrochemical storage media which discharging. There are presently three commercial function according to the principle: Electrode materi- suppliers, one of whom – VRB Power, headquartered al reacts with electrolyte. The lithium battery is the in Richmond, Canada – covers the wider spectrum only chemistry-free alternative: The ions are here from 5 to 10,000 kW. European Sales Manager Hugh pumped from one electrode to the other. Sharman estimates the 2008 turnover to have been Only a few of the battery concepts can be deemed one million dollars and sees an annual “doubling, if promising, as an overview reveals: not more”. According to Sharman, the concept has al- ready begun to steal business from the lead battery Lead battery: This is still the workhorse option. The in the field of telecommunications. lead battery is an inexpensive, technically mature system with a high level of efficiency, but also one Sodium-nickel chloride battery: This “high-tempera- significant drawback: the limited lifetime. The high ture” battery – also known as the “ZEBRA battery” – weight is generally not a problem for fixed-location requires an operating temperature of around 350°C applications. Lead batteries are thus the measure for to be maintained, though this can be guaranteed any new storage technology. It is difficult to imagine through its own heat generation while kept on charge. any kind of further “research breakthrough” for this The lifetime of the sodium-nickel chloride battery fur- battery type. The massive demand for standardised ther exceeds that of the vanadium redox flow battery, batteries for fixed installations, however, could force its efficiency ratio is better, and it is also a little the price down still further: whereas the cheapest cheaper in daily operation. Vital development re- The tasks for grid control lead batteries with slow discharge rates for non- search is still ongoing, as there are safety issues con- centres – like that of the E.on mobile use are priced at around 100 €/kWh, car start- cerning the molten sodium, which causes sealing Netz in Lehrte/Germany – er batteries cost barely 25 €/kWh. problems. The battery is currently undergoing testing would be made much simpler in electric vehicles. The only two fixed installations to in future if solar electricity Zinc-bromine battery: This type of battery is in the date are to be found in Canada and Great Britain. could be stored at the place of meantime no more expensive than a lead battery, but generation. achieves twice the lifetime. Even so, it has so far not Sodium-sulphur battery: This battery has a lot in advanced beyond demonstration projects with stor- common with the sodium-nickel chloride battery, in- age capacities of up to 500 kWh in the USA and Japan. cluding the high temperature, and is already in quite Sun & Wind Energy 4/2009 109 Photovoltaics energy storage widespread use in Japan – albeit for grid stabilisation water which is required for an open lead battery. This rather than for off-grid energy storage. Again as with is no doubt in part why nickel-cadmium batteries are the sodium-nickel chloride battery, there is only one still the only non-lead systems in use for 840 instal- manufacturer of such batteries. lations with off-grid photovoltaic generation in China, for example. One important disadvantage is the re- Lithium-ion battery: The market share of this battery duced capacity after a partial discharge. Moreover, type is increasing constantly. To date, however, the the batteries contain more than 0.002 % of the high- extremely high efficiency and low weight – a decisive ly toxic heavy metal cadmium, which means that they factor for laptops, mobile phones and vehicles – have been banned in the EU since 2008 – with the ex- must be traded off again high costs and inferior safe- ception of batteries for cordless electric tools. ty. Dirk Uwe Sauer nevertheless expects “a signifi- cant reduction in the costs to around 300 €/kWh for Nickel-metal hydride battery: These batteries incor- non-mobile batteries without peripherals in the com- porate a cathode with nickel hydroxide and an anode ing years”, and believes that the technology could of a metal hydride – a metal alloy capable of revers- play “a key role in many areas of electrical energy ible hydrogen storage. The electrolyte is an alkali of storage” in the medium term. This assessment is potassium. Nickel-metal hydride batteries have es- backed by the fact that there are many manufactur- sentially replaced their NiCd counterparts. The ener- ers and variants of the technology. On the other gy density is twice that of a nickel-cadmium battery, hand, the availability of lithium is as limited as that but they react sensitively to overcharging and over- of many other resources.
Load more

Recommended publications
  • Electrical Properties of Thin-Film Capacitors Fabricated Using High Temperature Sputtered Modified Barium Titanate
    Materials 2012, 5, 644-660; doi:10.3390/ma5040644 OPEN ACCESS materials ISSN 1996-1944 www.mdpi.com/journal/materials Article Electrical Properties of Thin-Film Capacitors Fabricated Using High Temperature Sputtered Modified Barium Titanate Glyn J. Reynolds 1,*, Martin Kratzer 2, Martin Dubs 2, Heinz Felzer 2 and Robert Mamazza 2 1 Oerlikon USA, Inc., Business Unit Systems, 970 Lake Carillon Dr, Suite 300, St. Petersburg, FL 33716, USA 2 OC Oerlikon Balzers AG, Business Unit Systems, Iramali 18, P.O. Box 1000, Balzers LI-9496, Liechtenstein; E-Mails: [email protected] (M.K.); [email protected] (M.D.); [email protected] (H.F.); [email protected] (R.M.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-727-290-2625; Fax: +1-727-290-2626. Received: 5 January 2012; in revised form: 27 March 2012 / Accepted: 29 March 2012 / Published: 13 April 2012 Abstract: Simple thin-film capacitor stacks were fabricated from sputter-deposited doped barium titanate dielectric films with sputtered Pt and/or Ni electrodes and characterized electrically. Here, we report small signal, low frequency capacitance and parallel resistance data measured as a function of applied DC bias, polarization versus applied electric field strength and DC load/unload experiments. These capacitors exhibited significant leakage (in the range 8–210 μA/cm2) and dielectric loss. Measured breakdown strength for the sputtered doped barium titanate films was in the range 200 kV/cm −2 MV/cm. For all devices tested, we observed clear evidence for dielectric saturation at applied electric field strengths above 100 kV/cm: saturated polarization was in the range 8–15 μC/cm2.
    [Show full text]
  • Super-Capacitor Integration Into Hybrid Vehicle Power Source
    Super-capacitor Integration into Hybrid Vehicle Power Source V. Bršlica Department of Electrical Engineering University of Defence in Brno Kounicova 65, 612 00 Brno (Czech republic) Phone/Fax number:+ 420 973 442319/ 443773, e-mail: [email protected] vehicle (BEV) that is driven by energy from house plug Abstract. The plug-in hybrid vehicle based on the concept stored during the night for short commute. Only in the of battery operated vehicle with strong electrical motor(s) and case of occasional longer trip the drive is supplied electrochemical battery is for thermal comfort of crew and for simultaneously from onboard generator, but this occasional elongated travel range completed by generator, operational range extension is paid by much higher fuel which is designed on average traction power only and during of consumption. Internal combustion engine (ICE) driving journey is mainly used in co-generative run for cabin heating. the generator delivers in cogeneration the thermal energy Such vehicle efficiency can be improved by the third power for cabin heating, with minimal fuel consumption in idle source, specifically used only for acceleration and regenerative run [6], [7]. The operating range 60 km does not need too braking purposes. That role is optimal for super-capacitor, big battery but no only the battery mass is reduced, also which has very good charging efficiency and can store the the battery power. energy from braking to the next acceleration. Both these actions are usually very fast with high power in very short time. Its sizing and voltage control is investigated in this paper. DC bus BATTERY Key words M MC Fuel save, hybrid vehicle, super-capacitor, power control, multi source supply G GC ABC 1.
    [Show full text]
  • Hybrid Electrochemical Capacitors
    Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 1-11-2018 Hybrid Electrochemical Capacitors: Materials, Optimization, and Miniaturization Richa Agrawal Department of Mechanical and Materials Engineering, Florida International University, [email protected] DOI: 10.25148/etd.FIDC006581 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Materials Chemistry Commons, Materials Science and Engineering Commons, Nanoscience and Nanotechnology Commons, and the Physical Chemistry Commons Recommended Citation Agrawal, Richa, "Hybrid Electrochemical Capacitors: Materials, Optimization, and Miniaturization" (2018). FIU Electronic Theses and Dissertations. 3680. https://digitalcommons.fiu.edu/etd/3680 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida HYBRID ELECTROCHEMICAL CAPACITORS: MATERIALS, OPTIMIZATION, AND MINIATURIZATION A dissertation submitted in partial fulfillment of the requirement for the degree of DOCTOR OF PHILOSOPHY in MATERIALS SCIENCE AND ENGINEERING by Richa Agrawal 2018 To: Dean John L. Volakis College of Engineering and Computing This dissertation entitled Hybrid Electrochemical Capacitors: Materials, Optimization, and Miniaturization, written
    [Show full text]
  • Prospects for the Development of High Energy Density Dielectric Capacitors
    applied sciences Review Prospects for the Development of High Energy Density Dielectric Capacitors Andrew Burke Institute of Transportation Studies, University of California, Davis, CA 95616, USA; [email protected] Abstract: In this paper, the design of high energy density dielectric capacitors for energy storage in vehicle, industrial, and electric utility applications have been considered in detail. The performance of these devices depends primarily on the dielectric constant and breakdown strength characteristics of the dielectric material used. A review of the literature on composite polymer materials to assess their present dielectric constants and the various approaches being pursued to increase energy density found that there are many papers in which materials having dielectric constants of 20–50 were reported, but only a few showing materials with very high dielectric constants of 500 and greater. The very high dielectric constants were usually achieved with nanoscale metallic or carbon particles embedded in a host polymer and the maximum dielectric constant occurred near the percolation threshold particle loading. In this study, an analytical method to calculate the dielectric constant of composite dielectric polymers with various types of nanoparticles embedded is presented. The method was applied using an Excel spreadsheet to calculate the characteristics of spiral wound battery cells using various composite polymers with embedded particles. The calculated energy densities were strong functions of the size of the particles and thickness of the dielectric layer in the cell. For a 1000 V cell, an energy density of 100–200 Wh/kg was calculated for 3–5 nm particles and µ 3–5 thick dielectric layers.
    [Show full text]
  • MASTER's THESIS Automotive Hybrid Technology
    2008:217 CIV MASTER'S THESIS Automotive Hybrid Technology Status, Function and Development Tools Gustaf Lagunoff Luleå University of Technology MSc Programmes in Engineering Mechanical Engineering Department of Applied Physics and Mechanical Engineering Division of Machine Elements 2008:217 CIV - ISSN: 1402-1617 - ISRN: LTU-EX--08/217--SE Abstract A diminishing oil reserve and increased environmental concern puts new demands on our vehicles. This thesis aims to identify the strengths and weaknesses of a conventional vehicle and explain the technology behind. Alternative energy sources are introduced and together with the knowledge learnt, their potentials are discussed. Unfortunately, none of them can be found to fulfil all future demands. Instead, hybrid vehicles are identified as a solution with high potential. Hybrid vehicles are consequently defined and the additional components are explained. The multiple energy sources of a hybrid vehicle bring increased drivetrain flexibility but also increased control complexity. With the goal to enhance the fuel economy and reduce emissions, optimum operating conditions are discussed for each drivetrain component and concrete control targets are extracted. Due to the complexity, computer modelling and simulation are expected to be an essential tool when it comes to hybrid vehicle development and optimization. As a result, cost efficient component models are suggested and finally a number of control optimization procedures are compared. The result of this thesis is a summary of relevant knowledge needed to reduce the development effort of hybrid vehicles. The key aspect is to understand the synergy effect of a hybrid drive train which enables the designer to approach the full potential of each component.
    [Show full text]
  • Proposal to Build Supercapacitors Using Solid Dielectrics
    Proposal to Build Supercapacitors Using Solid Dielectrics Frank Barnes (University of Colorado) — Boulder, Colorado, USA — [email protected] Animesh Banerjee (Indian Institute of Technology, Kharagpur, INDIA) Introduction With the ever increasing need for portability in electronic devices and the need for renewable energy storage, means of storing electrical energy is valuable. Batteries are generally used for such purposes, but for applications requiring high power for automobile start-ups, industrial applications, telecommunications, renewable energy storage and consumer electronics, supercapacitors would provide several advantages over the conventional Li-ion batteries and other electrochemical double layer ultracapacitors already commercialized [1,2]. They would also be suitable for power back-up functions in a wide range of consumer products, for solar panels and motor starts. Having supercapacitors which can pack up to 100 times the energy of conventional capacitors and deliver ten times the power of ordinary batteries would change the power equations for these and similar applications. Some of the advantages of employing supercapacitors would be: • They can be designed for the whole life of a consumer product (10 – 12 years) • Designing for life provides design engineers with the extra flexibility to locate the supercapacitors anywhere within the product. • They would be light weight, solid and rugged—apart from having higher energy density compared to the electrochemical double layer ultracapacitors which are being used widely. • In automobiles, they are the correct choices for electrical system stabilization, regenerative braking, power assist, starter generator, start/stop automatism and several other features. • In industries, they are required for peak power supply/ storage for robots and machines, crane recuperation, fork lifts, UPS & power quality, induction power transmission and space and medical equipment.
    [Show full text]
  • NAI Eestor Corp Presentation June 2019
    Investor Update June 2019 DISCLAIMER Certain statements and documents referred to in this presentation, other than statements of historical fact, may include forward-looking information that involves various risks and uncertainties that face the Company; such statements may contain such words as "may", "would", "could", "will", "intend", "plan", "anticipate", "believe", "estimate", "expect" and similar expressions, and may be based on manaGement's current assumptions and expectations related to all aspects of the automotive and capacitor industries, consumer demand for zero emission transportation solutions and the Global economy. Risks and uncertainties that may face the Company include, but are not restricted to: EEStor may not be able to replicate test results in mass produced commercial products; the EEStor capacitor and enerGy storaGe technoloGy may not be successfully commercialized at all, in a manner providinG the features and benefits expected while under development, or on a timely basis or the Company may not be able to successfully incorporate this technoloGy into its current or proposed products or the products of others; steps taken by the Company to protect its proprietary riGhts may not be adequate or third parties may infringe or misappropriate the Company's proprietary riGhts; the Company has a history of losses from operations and may not be able to obtain financing, if and when required or on acceptable terms due to market conditions or other factors, to fund future expenditures for General administrative activities,
    [Show full text]
  • Report to ZENN Board 22 October 2012 John Galvagni DRAFT
    Report to ZENN Motor Company 23 October 2012 John Galvagni Introduction Engagement: On 29 August, 2012, I was retained as a consultant to assist ZENN Motor Company Inc. (“ZENN”) in reviewing the technological developments at EEStor,Inc. of Cedar Park, Texas. (“EEStor”) and to provide a technical interpretation of EEStor’s products, manufacturing process, and technology. I understand that ZENN is both a shareholder of EEStor and has a technology agreement with EEStor that provides it certain rights to utilize the technology. I understand EEStor has been developing a capacitor technology which they expect will have Energy Storage Capability well in excess of today’s capacitors, and meeting or exceeding the Energy Density of current capacitors or batteries. Independence: I do not own any shares in ZENN and I confirm I have no arrangements or understandings with ZENN other than this consulting engagement. I am fully independent of ZENN for the purposes of providing the consulting services described herein. Qualifications I have been employed in the capacitor industry for over 40 years, and have more than 50 patents in the field. I retired in the spring of 2010 from AVX Corporation, a leading manufacturer of capacitors, as a Fellow in the Firm, the third of only five such positions at AVX since its founding in the 1930’s. Review of Visits to EEStor September 10 visit to EEStor: On September 10, 2012 I visited the EEStor facility in Cedar Park, Texas with representatives of ZENN. We met with Richard Weir, CEO of EEStor and Tom Weir, Vice President. We were given a tour of their manufacturing facility which has more than sufficient area for EEStor’s pre-production line, which line has been fully equipped with first level automation as well as necessary testing and metrology equipment.
    [Show full text]
  • Eestor Corp. Company Background
    EEStor Corp. (ESU:TSXV) Company Background: With an impressive portfolio of intellectual property and several key Joint Venture discussions in China, Europe and North America at advanced stages of completion, EEStor is on the verge of becoming a leading solutions provider in the vast global markets of passive electronics and solid- state energy storage. EEStor is developing new types of ceramic and polymer-based solid-state capacitor materials with the ultimate goal of replacing conventional battery technologies (lead acid and lithium-ion) with capacitors built with EEStor’s materials. This new generation of high energy density, low cost capacitor material is based on EEStor’s CMBT (Composition Modified Barium Titanate) ceramic dielectric powder. The Company is focused on licensing opportunities for its technology across a broad spectrum of industries and applications. Company Highlights: 1. Highly Experienced Management & Board of Directors • See below 2. Large & Growing Markets High Voltage High Dielectric Constant Capacitive Applications (De-coupling, Filters, Defibrillators, Inverters) • EEStor’s performance advantages: high voltage per layer/small footprint, high power, flexible, temperature stable, long life of over 1 million cycles, low amortized cost, non-toxic • According to a study from Global Market Insights, Inc. the market was $8 billion in 2016 and expected to grow to $19.8 billion by 2025 Electrochemical Capacitor Market (Grid Storage, Automotive, UPS, Railway Wayside, Pulse Power) • Electrochemical Capacitor Market to reach USD $2.18 Billion by 2022, CAGR of 20.7% (per MarketsandMarkets Supercapacitor Market - Global Forecast to 2022) High Voltage Power Factor Correction Capacitors (Grid Support and Stabilization) • Market of $1.9 billion with estimated growth of 5.0% per year (per – Paumanok Publications) 3.
    [Show full text]
  • Eesu Phev140
    Technology Assessment and Market Analysis of Solid State Ultracapacitors By Zibo Jiang B.Eng., the University of Birmingham, United Kingdom, 2006 Submitted to the Department of Materials Science and Engineering in Partial Fulfillment of the Requirements for the Degree of Master of Engineering in Materials Science and Engineering at the Massachusetts Institute of Technology September 2007 ©2007 Massachusetts Institute of Technology All rights reserved. Signature of A uthor ............. r.............. ... ..... .................................. ......... Department of Materials Science and Engineering August 15, 2007 C ertified by................................... ... ........................ .................. Yet-Ming Chiang Kyocera Professor of Ceramics Thesis Supervisor /7 Accepted by .................................. ............ .......... ........ ... Samuel M. Allen MASSACHUSTS INSTITUE OF T.CcZ+LOGY POSCO Professor of Physical Metallurgy ARCHIVES SEP 2 4 2W07 Chair, Departmental Committee on Graduate Students LIBRARIES TECHNOLOGY ASSESSMENT AND MARKET ANAYSIS OF SOLID STATE ULTRACAPACITORS By ZIBO JIANG Submitted to the Department of Materials Science and Engineering on August 15, 2007 in partial fulfillment of the requirements for the Degree of Master of Engineering in Materials Science and Engineering ABSTRACT This report provides quantitative analysis of Solid State Ultracapacitors (SSUs) from technological and financial perspectives. SSUs are Ultracapacitors with solid electrolytes predicted to have huge application potential
    [Show full text]
  • SUPERCAPACITORS FUNDA}Fientals of ELECTROCHEMTCAL CAPACTTOR DESTGN AI{D OPERATTON 7 Fv John R
    SUPERCAPACITORS FUNDA}fiENTALS OF ELECTROCHEMTCAL CAPACTTOR DESTGN AI{D OPERATTON 7 fV John R. MifLer and Patrice Simon /-r apacitors store electrical charge. UBecause the charge is stored physically, with no chemical or phase changes taking place, the process is highly reversible and the discharge-charge rycle can be repeated over and over again, virtually without limit. Electrochemical capacitors (ECs), variously referred to by manufacturers in promotional literature as "supercapacitors" or "ultracapacitors," store electrical charge in an electric double layer at the interface between a high-surface-area carbon electrode and a liquid electrolyte.l,2 Consequently, they are also quite properly referred to as electric double layer capacitors. A simple EC canbe constructed by inserting two conductors in a beaker containing an electrolyte, for examplg two carbon rods in salt water (Fig. 1). Initially there is no measurable voltage between the two rods, but when the switch is closed Frc. 2. Iclealistic representation of an electrolyte-filled right-cylindrical , nanopore in a carbon electrode of an electrochemical capacitor showing e the distributed resistance from the electrolyte and distributeil charge storage down the interior surface of the nanopore. pore, electrolyte conductivity being much less than carbon 'v conductivity. Charge stored near the pore mouth is accessible t. #*1- through a short path with small electrolyte resistance. In -[ +]- contrast/ charge stored deeper within the pore must traverse -T J_ a longer electrolyte path with a significantly higher series resistance. Thus, the overall response can be represented by a multiple-time-constant equivalent circuit mode1.4-6 lrrespective of this behavior, the-response time of an eLectrochemical capacitor in both charge aird discharge operation is extremely EI.ECTR{}Ll'TF] DLE{TROLITI short, about 1 second, as compared to batteries (minutes to tens of minutes).
    [Show full text]
  • Invented More Than 250 Years Ago – in 1745 to Be
    Cover frt.qxp:CVR FEATURE TEMP 8/5/08 15:06 Page 14 electrodes and some electrolyte, making it something of a hybrid between a capacitor and a battery. The most popular is the double layer capacitor, which stores the energy in the double layer formed near the carbon electrode surface. The amount of energy a conventional capacitor can hold is measured in microfarads – even nano or picofarads. In contrast, supercapacitors typically store farads, thousands of times more. Large commercial ones can store as much as 5000F. The energy density of today’s supercapacitors ranges from around 1 to 10Wh/kg, much higher than a standard capacitor but still only about a tenth of an NiMH battery. But as we shall see, this could change radically. One of the main benefits of supercapacitors is that they can be charged extremely quickly, in about 10s. This means large devices can be used for regenerative braking on vehicles. Hundreds of supercapacitors can be connected in series to provide the energy storage needed. Several transportation systems worldwide are now using them in such a way, for example in Shanghai and Mannheim. Charging ahead Will supercapacitors nvented more than 250 years ago – in 1745 to be Another of the supercapacitor’s advantages over Iexact – the humble capacitor has been a batteries is that it can be recharged and discharged enable an energy mainstay of electrical and electronic effectively an unlimited number of times. There is engineering, almost wherever energy needs to be little wear and tear induced by cycling and age does storage revolution? stored.
    [Show full text]