Japan's electronics giant Sony unveils the new bio battery, four cubic cells that generate enough electricity to drive a Walkman digital music player, at the company's headquarters in Tokyo. Sony developed a passive type bio battery system of breaking down sugar to generate the world's highest level electric power of 50mW from a cell as an ecologically-friendly energy.(AFP/Yoshikazu Tsuno)AFP - Bread and potatoes are sources of human energy, and now a carbohydrate diet is also powering up a Walkman.