Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

More safety for cell phone batteries

14.04.2008
Lithium-ion batteries supply the power for cell phones and PDAs, and larger devices such as laptops, cordless screwdrivers and lawnmowers are becoming increasingly dependent on this power source.

The advantage of these power storage devices lies in their high energy density and voltage (up to four volts). In terms of safety, however, they have one disadvantage – the organic electrolytes are inflammable and can easily catch fire. This has already resulted in several fires and subsequent recall campaigns. Researchers at the Fraunhofer Institute for Silicate Research ISC in Würzburg have optimized the safety of these batteries.

“We have succeeded in replacing the inflammable organic electrolytes with a non-flammable polymer that retains its shape,” says ISC team leader Dr. Kai-Christian Möller. “This considerably enhances the safety of lithium-ion batteries. What’s more, because it is a solid substance, the electrolyte cannot leak out of the battery.” The polymer used by the researchers is derived from the Ormocer® group of substances – a compound with silicon-oxygen chains that form an inorganic structure to which organic side chains become attached. The big challenge is to ensure that the polymers will efficiently conduct the lithium ions that supply the power for the cell phone and the PDA. “Normally, the more solid a polymer is, the less conductive it becomes. But we had numerous parameters that we could adjust – for example, we can use coupling elements with two, three or four arms. As a result, we have more possibilities with Ormocer®s than with a single type of plastic,” says Möller.

A prototype of the new lithium-ion batteries already exists, and the researchers will be presenting it at Hannover Messe (Hall 13, Stand E20). However, between three and five years are likely to elapse before the battery will cross shop counters in laptop computers, PDAs and cordless screwdrivers, the expert believes. The conductivity of the polymer needs further improvement to enable the battery to deliver or store as much power as possible in as short a time as possible. Once this happens, though, it is quite realistic to expect this type of battery – in conjunction with a capacitor – to be able to compete with the lead batteries in cars.

Redox flow batteries store solar energy Solar cells can be seen on the roofs of more and more houses today. The energy supplied by the sun and the wind is also increasingly being used on a large scale – in wind turbines and solar parks. But the energy supplied by the sun and the wind does not usually correspond to power requirements: On sunny days the solar cells often deliver more electricity than is needed, while solar energy may be in short supply when the sky is overcast. The amount of energy harvested from wind turbines fluctuates in a similar way.

In private solar energy plants, the surplus energy is stored in lead batteries until it is needed. The drawback of these storage systems is that they can only survive a limited number of cycles and normally have to be replaced after three to five years. In wind and solar parks, the energy is conserved by pumped storage plants. These, too, have a disadvantage: They have a relatively low rate of efficiency, which means that a lot of energy is lost. What is more, they take up a great deal of space. Redox flow batteries offer an alternative to lead batteries and pumped storage plants: They have a comparable energy density, but their service life is nearly ten times as long as that of lead batteries. So far, however, they are quite expensive in relation to their performance and energy density.

Researchers at the Fraunhofer Institute for Chemical Technology ICT in Pfinztal intend to change that situation in the years ahead: “We have developed the prototype of a redox flow battery that enables us to test various electrode materials, membranes and electrolytes as flexibly as possible,” reports ICT group leader Dr. Jens Tübke. “In this way, we can compare different redox systems in the same test set-up. This allows us to work out precisely what are the pros and cons of each system. It is not possible to compare the systems on the basis of existing documentation, as of course everyone measures them in a different test set-up.” The researchers will be presenting the test cell for the first time ever at the Hannover-Messe (Hall 13, Stand E20).

Monika Weiner | alfa
Further information:
http://www.fraunhofer.de/EN/press/pi/2008/april08.jsp

More articles from Power and Electrical Engineering:

nachricht Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz

nachricht Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>