Articoli con tag veicoli elettrici
Electric drive concepts for the cars of the future
Scritto da Giovanni Boldrini in Green technologies il 20 aprile 2010
Fonte: www.fraunhofer.de
The prospects look good that wheel hub motors will successfully become the accepted drive concept for electric vehicles. Fraunhofer researchers are engineering these motors, which are integrated into the car’s wheels. Scientists are testing these and several other components on the »Frecc0«, their demonstration vehicle. Working jointly in a multidisciplinary cooperation of 33 Fraunhofer institutes, they are paving the way for future technologies in all areas of electromobility. The »Fraunhofer System Research for Electromobility« makes its debut appearance at this year’s Hannover Messe (April 19 – 23, Hall 2, Booth D22).
The Fraunhofer wheel hub motor on the "Frecc0" demo vehicle.
In order to make electric cars a part of everyday life, new vehicle designs and parts are needed. Take wheel hub motors, for instance. One of the advantages of wheel hub motors is that manufacturers can dispense with the conventional engine bay – the space under the »hood« or »bonnet« – since the motors are attached directly to the wheels of the vehicle. This opens up a wealth of opportunities for car designers when drafting the layout of the vehicle. Additional advantages: By dispensing with the transmission and differential, the mechanical transmission elements suffer no losses or wear and tear. Moreover, the direct drive on each individual wheel may improve the drive dynamic and drive safety.
Cheaper, Stronger Lithium-Ion Batteries for Electric Vehicles
Scritto da Michele Frascaroli in Meccanica il 7 gennaio 2010
Fonte: www.technologyreview.com
A British company is testing new chemistry that could boost the performance of batteries.
By Duncan Graham-Rowe
A British defense technology company, Qinetiq, is testing a new type of lithium-ion battery for hybrids and electric vehicles that could be substantially cheaper and more powerful than existing batteries.
Packing power: The new battery pack, designed for a prototype hybrid diesel vehicle, is made with a novel lithium-ion chemistry that could boost the battery’s performance while bringing down the cost. Credit: Qinetiq
The battery is based on lithium-ion iron-sulfide chemistry, which has a number of advantages over the chemistry of existing batteries, says Gary Mepsted, technical manager for Qinetiq’s power sources group. The new battery would cost half as much as existing vehicle batteries and could last longer and recharge more quickly that other lithium batteries. Mepsted says that compared to standard lithium-ion batteries, the new battery has demonstrated about 1.6 times the energy density (which would extend a plug-in electric’s range) and a 50 percent higher power density (which would let hybrids charge and discharge more rapidly).
Researchers have long viewed lithium-ion batteries as an attractive alternative to the expensive metal-based batteries now used in hybrids. But although standard lithium-ion batteries are relatively cheap and can store about twice as much energy as standard nickel metal hydride cells, developers have had to overcome a number of technological challenges to make them practical for vehicles.
Plug-in electric vehicles need batteries with higher energy densities to extend their range between charges, says Mepsted. And for hybrids, the power density of standard lithium-ion batteries is less than ideal for coping with the rapid charging and discharging that comes with the regenerative braking systems used in hybrids. Continua a leggere…
High-Energy Batteries Coming to Market
Scritto da Michele Frascaroli in Meccanica il 28 ottobre 2009
Fonte: Technology Review
Rechargeable zinc-air batteries can store three times the energy of a lithium-ion battery.
By Kevin Bullis (Technology Review)
A Swiss company says it has developed rechargeable zinc-air batteries that can store three times the energy of lithium ion batteries, by volume, while costing only half as much. ReVolt, of Staefa, Switzerland, plans to sell small “button cell” batteries for hearing aids starting next year and to incorporate its technology into ever larger batteries, introducing cell-phone and electric bicycle batteries in the next few years. It is also starting to develop large-format batteries for electric vehicles.
Battery unpacked: This graphic illustrates the multilayered structure of a ReVolt rechargeable zinc-air battery. From top to bottom: the battery cover, which lets in air; a porous air electrode; the interface between electrodes; the zinc electrode; the casing. Credit: ReVolt
The battery design is based on technology developed at SINTEF, a research institute in Trondheim, Norway. ReVolt was founded to bring it to market and so far has raised 24 million euros in investment. James McDougal, the company’s CEO, says that the technology overcomes the main problem with zinc-air rechargeable batteries–that they typically stop working after relatively few charges. If the technology can be scaled up, zinc-air batteries could make electric vehicles more practical by lowering their costs and increasing their range.
Unlike conventional batteries, which contain all the reactants needed to generate electricity, zinc-air batteries rely on oxygen from the atmosphere to generate current. In the late 1980s they were considered one of the most promising battery technologies because of their high theoretical energy-storage capacity, says Gary Henriksen, manager of the electrochemical energy storage department at Argonne National Laboratory in Illinois. The battery chemistry is also relatively safe because it doesn’t require volatile materials, so zinc-air batteries are not prone to catching fire like lithium-ion batteries. continua a leggere…
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