Call for safer batteries answered
Mobile electrical devices such as phones, PDAs or laptops are part of everyday life. We carry these gadgets everywhere and rely on them to make our lives that little bit easier. However, concerns over the safety of these devices were recently raised after laptops were recalled because of faulty, potentially flammable batteries. A team of European researchers have now created a new battery that promises to be safer and non-flammable. Almost everything these days seems to be portable, from phones to computers, which is made possible thanks to advances in battery technology. The most commonly used type of battery in electronic devices is lithium-ion batteries. Every year, these batteries seem to get smaller and smaller. At the same time, they are capable of supplying more and more power. However, these advances are not without their technological snags. Recently, several computer manufacturers had to recall the lithium-ion batteries used in their laptops, after complaints that the batteries were overheating and burning the user's laptop. Several incidents of these batteries spontaneously combusting were also reported. This is why a team of European researchers based in Würzburg, Germany, have developed the latest in battery technology to ensure the safety of its users. The new lithium-ion battery is based on a polymer electrolyte instead of the liquid electrolyte used in conventional lithium-ion batteries. The difference means that unlike the old style batteries, this new type is non-flammable. The reason why lithium-ion batteries have become so popular is their high-energy density and voltage output of up to four volts. In terms of safety, however, they have one disadvantage; the organic electrolytes used in their construction are inflammable. Researchers at the Fraunhofer Institute for Silicate Research (ISC) in Würzburg therefore looked at optimising the safety of these batteries. 'We have succeeded in replacing the inflammable organic electrolytes with a non-flammable polymer that retains its shape,' says Dr Kai-Christian Möller, ISC team leader. '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 biggest hurdle faced by the researchers in creating this new battery was to ensure that the polymers would efficiently conduct the lithium ions that supply the power. '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 [the special polymers used] than with a single type of plastic,' says Dr Möller. While a prototype already exists, the team predicts that it may take up to three to five years before it will be readily available for average consumers. Further improvement is still required to enhance the conductivity of the polymer so as to allow the battery to deliver as much power as possible in as short a time as possible. Research is also being conducted into its application for solar energy battery packs. As solar energy is reliant on the sun, there are times when peak energy periods may not correspond to peak energy use. This means that there is a need for a place to store the energy for when it is required. These batteries offer an alternative to lead batteries and pumped storage plants thanks to their energy density.
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Germany