Your solar powered mobile phone love a Sun Bath.

For the researchers, employing micro fuel cells as chemical power converters represents a focal area in supplying power for mobile devices. For example, the flat micro fuel cells from the Fraunhofer Institute for Reliability and Microintegration IZM are made of polymer and metallic films and based on wafer level- and film technologies. Three individual cells connected in series achieve an aggregate voltage of around 1.5 V, which is sufficient to replace conventional button cells, for instance.

The ISE, too, has already presented several micro fuel cell systems with power ratings ranging from a few mW up to several hundred watts. The researchers are exploring various ways of producing hydrogen: one method utilizes chemical hydrides such as sodium borohydride or borazan to produce hydrogen by introducing heat or water, or by employing catalysts. Another involves converting liquid methanol to hydrogen in direct methanol fuel cells (DMFC). A further possibility is offered by the use of micro-reformers, where hydrogen is produced from hydrocarbons such as ethanol, diesel fuel or liquefied petroleum gas.

Future efforts to optimize power supply systems for mobile devices will increasingly involve the use of multiple power generation technologies with an electric buffer store. In order to achieve maximum power utilization with the highest degree of efficiency, a system of intelligent power management is needed. The goal is to link the energy delivered by batteries, solar cells, thermoelectrics or fuel cells in a device. With this kind of system, a laptop could switch to fuel cells when the battery is depleted, and this in turn would be continuously recharged by the solar cells whenever light conditions were favorable. Power management ensures that MP3 players, mobile phones and notebooks always have an optimal power supply.