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 Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>