Flexible Batteries That Never Need to Be Recharged

European researchers have built prototypes that combine plastic solar cells with ultrathin, flexible batteries. But don’t throw away your battery recharger just yet.

Solar battery: European researchers have integrated thin-film organic solar cells with a flexible polymer battery to produce a lightweight and ultrathin solar battery for low-wattage electronic devices, such as smart cards and mobile phones. The battery can recharge itself when exposed to natural or indoor sunlight, meaning that some electronic gadgets would never need a separate charger. Researchers predict that such a device could be commercially available in some products next year.  (2008)
Credit: G. Dennler, Solar Energy

Prototypes of the solar battery weigh as little as two grams and are less than one millimeter thick. “The device is meant to ensure that the battery is always charged with optimum voltage, independently of the light intensity seen by the solar cell,” according to the paper. Dennler says that a single cell delivers about 0.6 volts. By shaping a module with strips connected in series, “one can add on voltages to fit the requirements of the device.”